125 years of innovation - PART III


Stuttgart, Germany, Dec 14, 2010

125 years of technological leadership: Innovative powertrain engineering for efficient, environmentally compatible driving enjoyment

Development of fundamental technologies for particularly efficient, environmentally compatible vehicles has been a recurring theme in the history of the company and brand right from the early years. Mercedes-Benz has been the first to bring numerous relevant technologies to production and market maturity, and continues to develop them further: from the fast-running petrol engine – the fundamental basis for the invention of the motor car – to the automotive diesel engine and direct petrol injection, and right up to alternative technologies such as the fuel cell drive system. And the brand will also continue to ensure individual mobility in the future.

In the early 1920s, Daimler-Motoren-Gesellschaft adapted mechanical supercharging of the internal combustion engine, which it had brought to production maturity for aviation engines, for use in motor cars. Thanks to supercharging, the Mercedes models 6/25 hp and 10/40 hp offered more output and greater efficiency than comparable engines without supercharging. This principle remains valid to the present day and brings even more advantages in the form of turbocharging, as the current BlueDIRECT engines from Mercedes-Benz demonstrate.

One of the outstanding innovations in powertrain engineering came in 1936, with the introduction of the 260 D as the world's first diesel passenger car in series production. In 1954 Mercedes-Benz presented the legendary 300 SL as the first series production passenger car equipped with a four-stroke engine featuring direct petrol injection. Further milestones in the development of more efficient, more environmentally compatible internal combustion engines include the first series production passenger car with a turbocharged diesel engine in 1977, common-rail direct injection (CDI) in 1997 and the BlueTEC emission control system in 2005 - initially in trucks, and in passenger cars in 2006. This technology makes the economical diesel as clean as petrol engines.

The company has also taken a pioneering role from the start when it comes to alternative drive systems. From 1906, Mercedes passenger cars, trucks, buses and fire service vehicles became available with battery-electric or hybrid drive. In the late 1960s development work on electric and hybrid drive systems recommenced. This was accompanied by intensive development and testing of internal combustion engines powered with natural gas, alcohol-based fuels and hydrogen.

In 1994 Mercedes-Benz caused a sensation with the NECAR 1, the first car with a fuel cell drive system. Since then the development of this technology has made enormous strides, and locally emission-free fuel cell and electric vehicles now impress with their high torque and agility. And in 2010 the first electric cars built with the very latest technologies under series production conditions were launched: the fuel cell powered B-Class F-CELL and the A-Class E-CELL with battery-electric drive.

Optimum solutions for every requirement

The subject of emissions control has also been topical for decades. Mercedes-Benz accepts no compromises in this field either, and already began offering the then unrivalled lambda-controlled 3-way catalytic converter for all petrol engines in 1985. An oxidising catalytic converter for diesel engine models became available in 1990. After its debut in trucks in 2005, BlueTEC, the technology for the world's cleanest diesels, was first brought to market in passenger cars with the E 320 BlueTEC one year later.

The key to environmentally compatible and at the same time need-related automobility is an intelligent mix of different drive technologies: for long-distance operations, optimised internal combustion engines with and without a hybrid module are the most efficient solutions for the foreseeable future, while electric vehicles are ideally suited to operations in urban areas.
These findings are the basis of the BlueEFFICIENCY strategy adopted by Mercedes-Benz, which has three areas of emphasis:

- Optimisation of vehicles with internal combustion engines by the use of efficiency-enhancing technologies, as in the new-generation four-cylinder diesel engines or the BlueDIRECT direct petrol injection engines,

- Further efficiency improvement using tailor-made hybrid drive systems such as in the S 400 HYBRID, the first series-production vehicle with a lithium-ion battery, the diesel-hybrid E 300 BlueTEC HYBRID and the S 500 Plug-in HYBRID, and

- Locally emission-free driving with electric vehicles with fuel cell or battery-electric drive, initially in the models B-Class F-CELL and A-Class E-CELL.

This three-pronged Mercedes-Benz powertrain strategy not only offers an impressively wide range of available technologies, but also the greatest possible flexibility in their use. Even within all the conceivable transitional scenarios, it optimally meets the varied requirements of different customers and markets.

Mercedes-Benz: the driving force for sustainable mobility

Mercedes-Benz will therefore continue to be the driving force for sustainable mobility in the future, and is working intensively on its further development in every area, ‑ from individual mobility and public bus transport to goods transport with commercial vehicles and special segments that are covered by e.g. the Unimog. The powertrain technology is tailored to the relevant customer needs and type of operation.

But for Mercedes-Benz, sustainability does not only mean researching

environmentally friendly, efficient drive systems, making them a practical proposition for day-to-day use and continuously improving them. The development of environmentally compatible cars also involves continuous improvement in the areas of weight reduction, aerodynamics, rolling resistance and energy management.

Mercedes-Benz even goes one step further than this, however: one principle enshrined in the corporate environmental guidelines is that the environmental effects of the company's products and activities are to be considered over the entire lifecycle, and constantly reduced. This comprehensive approach by Mercedes-Benz therefore encompasses the entire research and development process, includes the suppliers and logistics, takes production and sales/distribution into consideration, and takes equal account of each model's use and eventual recycling.

Around 18,800 personnel work in the company's research and development departments around the world. One of the major focuses of their work is the minimisation of emissions and energy consumption during product production, operation and recycling.

The aim of all these efforts is also to safeguard mobility for generations to come, despite ever-increasing requirements. Mercedes-Benz engineers have been working intensively on this for several decades, and demonstrate on a daily basis that as the inventor of the motor car, Mercedes-Benz is also shaping its future with passion and responsibility.

Pioneer in alternative powertrain technologies

A look back at the history of Mercedes-Benz is positive proof that even more than 100 years ago, the brand was intensively concerning itself with many innovations that are nowadays very topical in the automotive industry. A Mercedes model with a hybrid drive system was produced as early as 1902, for example. In this now decidedly modern drive configuration based on the Mercedes-Simplex 28 hp, the petrol engine powers a generator to drive electric wheel hub motors in the front wheels.

This drive configuration entered series production at the end of 1906, at the Austrian subsidiary of Daimler-Motoren-Gesellschaft which marketed passenger cars and buses under the name "Mercedes Mixte". The model range also included "Mercedes Electrique" models, whose electric wheel hub motors were fed by a battery. They were available in various versions as passenger cars, trucks, buses, ambulances and fire service vehicles.

Even though these alternative drive configurations were not able to establish themselves firmly at the time, the development of fundamental technologies for particularly efficient, environmentally compatible vehicles has been a recurring theme in the history of the company and brand right from the early years. Many of these technologies were first brought to production and market maturity by Mercedes-Benz, and further development continues: from the fast-running petrol engine – the fundamental basis for the invention of the motor car – to the automotive diesel engine and direct petrol injection, and right up to alternative technologies such as the fuel cell drive system. And the brand will also continue to ensure individual mobility in the future.

In the early 1920s, Daimler-Motoren-Gesellschaft adapted mechanical supercharging of the internal combustion engine, which it had brought to production maturity for aviation engines, for use in motor cars. Thanks to supercharging, the Mercedes models 6/25 hp and 10/40 hp offered more output and greater efficiency than comparable engines without supercharging. This principle remains valid to the present day and brings even more advantages in the form of turbocharging, as the current BlueDIRECT V8 engines from Mercedes-Benz demonstrate.

First series-production car with diesel engine and direct petrol injection

In 1936 an even more important milestone in automotive history was reached with the first series-production passenger car powered by a diesel engine, with a consequent and major reduction in fuel consumption. The Mercedes-Benz 260 D consumed around 30 percent less fuel than its opposite number with a petrol engine, and at the time diesel fuel was also half the price of petrol. It was a trendsetter, and well ahead of its time. The same applies to the 300 SL of 1954. The legendary "Gullwing" was not only voted "Sports Car of the Century", but was also the first series production car to feature direct petrol injection in a four-stroke engine. The benefits in terms of performance and efficiency are considerable, as the modern CGI and BlueDIRECT engines from Mercedes-Benz impressively demonstrate.

1975: First trials with hydrogen drive systems

The company's experimental work on alternative drive systems also has a long history, as far back as 1975 in the case of hydrogen power, for example. The first fuel cell powered NECAR (New Electric Car) based on the MB 100 van was already on the road in 1994.

The subject of emissions control has also been topical for decades. Mercedes-Benz accepts no compromises in this field either, and already began offering the then unrivalled lambda-controlled 3-way catalytic converter for all petrol engines in 1985. An oxidising catalytic converter for diesel engine models became available in 1990. After its debut in trucks in 2005, BlueTEC, the technology for the world's cleanest diesels, was first brought to market in passenger cars with the E 320 BlueTEC one year later.

In 2010 the first series-production electric cars featuring the very latest technology were launched: the B-Class F-CELL with fuel cell drive and the A-Class E-CELL with battery-electric drive. The key to environmentally compatible and at the same time need-related automobility is an intelligent mix of different drive technologies: for long-distance operations, optimised internal combustion engines with and without a hybrid module are the most efficient solutions for the foreseeable future, while electric vehicles are ideally suited to operations in urban areas. These findings are the basis of the BlueEFFICIENCY strategy adopted by Mercedes-Benz, which has three areas of emphasis:

- Optimisation of vehicles with internal combustion engines by the use of efficiency-enhancing technologies, as in the new-generation four-cylinder diesel engines or the BlueDIRECT direct petrol injection engines,

- Further efficiency improvement using tailor-made hybrid drive systems such as in the S 400 HYBRID, the first series-production vehicle with a lithium-ion battery, the diesel-hybrid E 300 BlueTEC HYBRID and the S 500 Plug-in HYBRID, and

- Locally emission-free driving with electric vehicles with fuel cell or battery-electric drive, initially in the models B-Class F-CELL and A-Class E-CELL.

Depending on the model series, the tailor-made BlueEFFICIENCY packages for series-production cars encompass various in-engine measures and a combination of different technologies to save weight in the bodyshell, ‑ among them a weight-optimised, laminated windscreen and lightweight wheels. From series to series, other measures include low-friction tyres with reduced rolling resistance and aerodynamic improvements designed to reduce drag, for example a lowered suspension, modified engine compartment and underbody panels, partial masking of the radiator grille, redesigned exterior mirror housings and smooth underbody panelling.

ECO start/stop function: preliminary stage of hybridisation

BlueEFFICIENCY measures also include the ECO start/stop function as a preliminary stage of hybridisation. This makes for further fuel savings, and is gradually being introduced in all Mercedes-Benz model series. Energy-saving demand control of the air conditioning compressor, power steering, generator and fuel pump is another efficiency measure.

Displays in the speedometer inform the driver how much fuel is currently being consumed, and when he should shift to the next higher gear in the interests of an economical and environmentally conscious style of driving.

With expertise built up over 125 years and a wide range of ultra-modern powertrain technologies that is unrivalled by any other automotive brand, Mercedes-Benz is ideally equipped to safeguard mobility for future generations despite ever-increasing requirements.

Daimler and Maybach develop the first car engine

As the "heart of the motor car" the engine is the most important component, and one whose development made the invention of the motor car possible in the first place. It must be compact and light enough to be accommodated in a vehicle, and powerful enough to drive it. Such an engine did not exist until Gottlieb Daimler and Wilhelm Maybach built the world's first high-speed petrol engine in 1883.

The gas-operated four-stroke engine invented by Nikolaus Otto in 1876 was unsuitable for vehicles owing to its size and weight. With an output of 1 hp (0.7 kW), which it developed at an engine speed of 180 rpm, it weighed over 500 kilograms. With painstaking efforts, Daimler and Maybach developed the first vehicle engine on the basis of Otto's four-stroke principle. One major precondition for successful 'downsizing' was an increase in engine speed, and this was achieved with the help of hot-tube ignition and speed regulation.

1883: The first experimental engine gets up to speed

The first experimental engine of 1883, which was equipped with both new features, still operated on gas and achieved a then unbelievable cycle speed of 600 rpm. The hot-tube ignition system, which appears more than crude by today's standards, ignited the fuel/air mixture by means of a red-hot tube heated by a petrol-fed flame that projected into the combustion chamber.
To provide a reliable fuel supply when on the move, Daimler and Maybach developed a carburettor. In 1885 they used this in the first high-speed engine that was petrol-operated and could be installed in a vehicle. Owing to its shape, it was given the name "grandfather clock". In the same year Daimler and Maybach first tested it in a wood-framed two-wheeler, which became the world's very first motorcycle, and in 1886, as part of these initial trials, they also installed it in a coach and a boat.

Low weight, high output: the "grandfather clock"

The "grandfather clock" weighed only 92 kilograms, and developed an output of 1.1 hp (0.8 kW) from a cubic capacity of 462 cc. These figures amply illustrate the great achievement of Daimler and Maybach. A conventional Otto gas engine with a comparable output weighed more than five times as much, and had more than five times the cubic capacity. In contrast to Daimler's motor coach, Carl Benz used a distinctive, purpose-built design for the three-wheeled motor wagon for which he registered a patent on 29 January 1886.

Independently of Daimler, Benz was also able to develop a high-speed petrol engine, though with a speed of 400 rpm it was not quite as efficient as Daimler's "grandfather clock": the Benz engine developed an output of 0.75 hp (0.55 kW) from a cubic capacity of 954 cc. In contrast to Daimler, Benz already used an electric spark-plug ignition system and was therefore ahead of his time. In the early years of the motor car, the ignition system was one of the greatest challenges for reliable day-to-day operation.

Mercedes 35 hp: the progenitor of the modern-day motor car

The Mercedes 35 hp of 1901 is regarded as the progenitor of the modern-day motor car - above all because of its innovative overall design, which for the first time established a distinctive shape for the motor car and marked a departure from the coach-based design prevalent in the industry. Its engine also had numerous seminal features. The powerful four-cylinder in-line engine with its thin-walled light-alloy crankcase was rigorously designed to save weight, and also installed low down in the vehicle frame. It weighed only 210 kilograms – an enormous advance over the 300 kilograms of the preceding model. The intake valves - previously taking the form of a pressure-relief valve that opened automatically by vacuum pressure on the intake stroke - were now controlled by a camshaft, like the exhaust valves. This improved smoothness, idling and acceleration, providing engine characteristics that were previously thought hardly possible.

The honeycomb radiator: opening the way for more powerful engines

One of the most sensational and still basically unchanged inventions incorporated into this first Mercedes was the honeycomb radiator, a considerably improved variation on the tubular radiator invented by Wilhelm Maybach, which first made an enclosed cooling system possible in 1897 and marked a milestone in engine cooling technology.

The larger cross-section of the square tubes, and the smaller gap between them, allowed a significant improvement in cooling performance. Moreover, the volume of coolant was reduced by half compared to the tubular radiator. A small ventilator assisted the cooling action when driving at slow speed. This finally made cooling problems, which were then a major obstacle to the development of more powerful engines, a thing of the past.

The major progress brought by the introduction of the closed cooling system is illustrated by the example of an early long-distance journey: in July 1894 the Bohemian industrialist Theodor von Liebieg and his Benz Victoria undertook a 939 kilometre long drive from Reichenberg in Bohemia via Mannheim to Gondorf on the Moselle River. His Benz motor car consumed around 20 litres of petrol per 100 kilometres during the journey, but also 150 litres or so of water, which had to be constantly replenished. This high coolant consumption was due to the high rate of evaporation from the open cooling system.

Closed systems, on the other hand, inherently have no water consumption. The Daimler Phoenix of 1898, which was equipped with a tubular radiator, had a coolant capacity of 18 litres, while the much more efficient honeycomb radiator made do with only 9 litres – with a consequent weight-saving of 9 kilograms.

Downsizing: already a recipe for success in 1911

In parallel with the growing industrialisation of the motor car, Mercedes-Benz continued to develop its engine technology further. An internal design competition at Benz produced the model 8/18 hp, which the company presented in 1911. This was an early example of what is now known as "downsizing" for improved efficiency: compared to the equally powerful Benz 18 hp of 1905, the new four-cylinder had an almost 40 percent smaller cubic capacity. This not only made the model 8/18 hp more economical, but also placed it in a much more favourable tax category – the luxury tax imposed on cars in 1906 was based on cubic capacity.

At the time, a motor car's tax category was prominently shown by its model designation. In the early years of the twentieth century, passenger cars were quite straightforwardly named according to their output. From 1909 the output figure was preceded by a second figure, the so-called "tax-horsepower" indicating the displacement-based tax category. One tax-horsepower corresponded to 262 cc of cubic capacity. Accordingly the Benz 8/18 hp had an output of 18 hp and 8 tax-horsepower - corresponding to a displacement of around 2100 cc.

The Benz Special Touring Car designed for the 1910 "Prince Heinrich Rally" employed four-valve technology as a means of increasing output and efficiency. Two intake and two exhaust valves per cylinder increased the gas throughput. The greater volumetric efficiency made an increased output and more efficient use of fuel possible.

1921: improved charging and more output thanks to the supercharger

As early as 1921, Mercedes presented the first regular production cars whose output and efficiency were noticeably improved by supercharging. A compressor driven by the engine forced the petrol/air mixture into the cylinders under pressure, so that these were more effectively charged and delivered considerably more power. Originally introduced in the smaller models, supercharging became a key technology at Mercedes-Benz in the 1920s and 1930s - especially in racing, sports and luxury cars. From 1995 onwards, supercharged engines were once again used by Mercedes-Benz: in the quest for the desired performance potential, supercharging allows smaller engines with lower fuel consumption and emission figures. Today Mercedes-Benz is increasingly opting for the use of turbocharging, which allows even higher efficiency in combination with direct petrol injection.

Petrol injection is another output and efficiency-enhancing technology that was developed and brought to series-production maturity by Mercedes-Benz. Like the supercharger, petrol injection has its roots in the development of aero-engines. In this case, as with supercharging, the primary concern is to increase engine output to compensate loss of power at higher altitudes.
In 1936 the DB 601 V12 aero engine developed by Mercedes-Benz became the world's first series-production engine with petrol injection, the fuel being injected directly into the cylinder. In the early 1950s Mercedes-Benz also successfully brought this innovative technology to production maturity for car engines. It was employed in the 300 SL high-performance sports car of 1954, and also in the new W 196 Formula 1 racing car. In both cases the primary aim was to increase engine output, but the accompanying improvement in efficiency was a welcome side benefit.

300 SL of 1954: first regular production car with direct petrol injection

In 1954 the legendary Mercedes-Benz 300 SL "Gullwing" was the world's first regular production car with a four-stroke petrol engine to feature direct petrol injection. This produced a high output for a low fuel consumption, despite the comparatively small cubic capacity. Nowadays Mercedes-Benz concertedly uses direct petrol injection in combination with downsizing, turbocharging and start/stop technology to achieve new peak values for output, torque, fuel consumption and emissions.

From 1957 Mercedes-Benz moved from direct injection to manifold injection, where the petrol is not injected directly into the cylinder, but into the intake manifold. At the time this variation was better suited to large-scale production, and following its introduction in the model 300 (W 189) of 1957, it was gradually adopted for all the model series. Initially reserved for the luxury and SL models, it was introduced into the model 250 CE (W 114), the top model in the new "Stroke/8" Coupé series, in 1968. Another new feature was the electronic control system, which ensured lower fuel consumption and lower emissions, and replaced the previous, mechanically controlled variant until 1972.

In 1980 Mercedes-Benz introduced its first four-cylinder engine with petrol injection, a completely new 2.3 litre engine development which replaced the previous carburettor engines in the saloon, coupé and estate models of the 123-series. Despite developing 25 percent more output, the new models were around ten percent more economical than their predecessors.

Reduced fuel consumption and lower emissions

In addition to a further lowering of fuel consumption, a continuous reduction in exhaust emissions has already been one of the most important environmental goals of Mercedes-Benz since the mid-1960s. At the same time the company has always placed its main emphasis on the avoidance of emissions by ensuring the cleanest, most residue-free fuel combustion possible within the engine.

For the greatest possible reduction in emissions, the in-engine measures designed to achieve this are best combined with aftertreatment of the exhaust gases. Above all, the use of catalytic converters to control the emissions of petrol engines has been intensively researched since the end of the 1960s. In 1985 this research led to the presentation of a model range in which all petrol-engined Mercedes-Benz passenger cars were also available with a closed-loop, three-way catalytic converter. From 1986, this then unrivalled emissions control process became standard equipment for all Mercedes-Benz passenger cars with a petrol engine.

From 1990: petrol injection for all Mercedes models

Catalytic emissions control, which was subsequently the subject of continuous further development to comply with increasingly stringent emission limits, eventually led Mercedes-Benz to phase out models with a carburettor engine. In 1985 the carburettor models in the compact class and medium class were equipped with an electronically controlled carburettor that was compatible with closed-loop emissions control, but five years later production of these models was discontinued. This means that since the mid-1990s, the range of Mercedes-Benz passenger cars with petrol engines only has models with petrol injection.

In mid-2002 Mercedes-Benz introduced a new generation of four-cylinder engines which combined a number of different, efficiency-enhancing technologies under the name TWINPULSE system: supercharging, four-valve technology, microprocessor controlled petrol injection and variably adjustable camshafts. The technologically most sophisticated variant of the TWINPULSE engine was not equipped with the usual manifold or duct injection, but rather used a direct petrol injection principle known as CGI (charged stratified gasoline injection). This combination allows particularly good fuel economy together with reduced exhaust emissions.

Significant fuel saving despite more power

In 2006 Mercedes-Benz presented the world's first piezoelectric direct injection with a spray-guided combustion process: despite 20 hp more output, the V6 of the CLS 350 CGI consumes ten percent less petrol.

Mercedes-Benz also followed the principle of downsizing to improve efficiency: this uses smaller engines with a lower cubic capacity or fewer cylinders - plus turbocharging - to achieve the same output levels as a larger engine while consuming less fuel. The reason: engines with a smaller displacement have lower friction losses, leading to greater volumetric efficiency. For the same output, fuel consumption and therefore the volume of emissions fall by 15 to 20 percent.
In autumn 2009 the new four-cylinder turbocharged direct petrol injection engines in the E-Class achieved significant fuel savings for the same output versus the six-cylinder engines of the preceding models.

BlueDIRECT: new standard in efficiency

In May 2010 Mercedes-Benz reached a new milestone with regard to efficiency: thanks to further innovations such as latest-generation direct injection, fully variable valve timing, new combustion processes and multi-spark ignition, the new BlueDIRECT V6 and V8 engines consume up to 24 percent less petrol than their predecessors while delivering more output and torque. In the future, more economy potentials will be realised with fuel-efficient stratified combustion, reductions in in-engine friction losses and lower power consumption by the peripheral units.
The modular Mercedes-Benz engine concept allows maximum flexibility with a variety of cylinder numbers, cubic capacities and output levels, configuration as a naturally aspirated or turbocharged unit, and scope for need-related combination with all-wheel drive and hybrid systems.

Mercedes-Benz diesel engines: economical and ever-cleaner

Mercedes-Benz is the pioneer in automotive diesel engines – both for commercial vehicles and passenger cars. From its early years right up to the 1970s, the diesel was seen as the epitome of efficiency, durability and reliability – though also of sluggish performance. In subsequent years, trailblazing innovations turned the diesel engine into an outstanding torque generator. The milestones on this road include turbocharging, four-valve technology, electronic engine management and common-rail direct injection.

Mercedes-Benz has made a major contribution to the development of all these technical features and their introduction into large-scale production, thereby also making the diesel engine respectable for luxurious, elegant and sporty car models.

In every vehicle class, the Mercedes-Benz diesel range offers powerful, high-torque alternatives for lovers of dynamic driving who also want low fuel consumption and low emissions. Making the diesel engine usable for road-going vehicles was one of the most important milestones in automotive development. Once the diesel engine had overcome its prototype stage and entered production in the early years of the 20th Century, it was for many years used only as an industrial engine or to power ships and railway vehicles.

It was only in 1920 that its use in road vehicles became possible, when the Benz & Cie. engineer Prosper L'Orange developed the technical basics with the pre-chamber injection principle. The first use of the automotive diesel engine was in 1923, in a Benz-Sendling motorised plough.

Following successful trials of this two-cylinder diesel engine, the Benz Executive Board sanctioned the series production of a four-cylinder engine with pre-chamber injection in April 1923. The first test using a Benz 5-tonne truck equipped with this engine took place in September 1923. In February 1924 this very first diesel truck was presented at the Amsterdam Motor Show, and the first example was delivered to a customer in September 1924: Robert Bosch GmbH, the company which developed the injection pump.

Mercedes Benz 260 D: also the first "open" diesel car

From the early 1930s Mercedes-Benz worked on the development and refinement of a smaller diesel engine for use in a passenger car. The result appeared in 1936: the Mercedes-Benz 260 D was the world's first series-production car with a diesel engine. It had its debut in February 1936, the "50 years of automotive engineering" anniversary year, at the International Motor Vehicle and Motorcycle Exhibition in Berlin.

In its convertible version, which was added to the model range in autumn 1936, the Mercedes-Benz 260 D was also the world's first "open-top" diesel car, and therefore a trendsetter that was decades ahead of its time. Today the quiet, powerful and at the same time highly efficient CDI engines in the E-Class Cabriolet are an indispensable part of the product portfolio.

In the ensuing years Mercedes-Benz achieved further milestones in diesel engine development. Numerous technological innovations allowed more output and torque accompanied by lower fuel consumption and emissions. In 1936 the 260 D already consumed around four litres less fuel per 100 km than its petrol-powered equivalent, the model 230. In relation to output, a diesel car nowadays consumes up to ten times less fuel than in 1936.

In 1949 Mercedes-Benz continued the success story of the diesel passenger car with the 170 D, the first diesel model of the post-war period, which finally achieved the breakthrough for this relatively recent technology. In 1963 Mercedes-Benz also offered an automatic transmission for the first time in a diesel car - the 190 D - once again underlining its claim to give customers only the best in meeting their constantly growing expectations and wishes.

Diesel engine: half a million units by 1965

Sales figures increased rapidly thanks to the growing range of available features and the engine's legendary indestructibility: the 500,000th Mercedes-Benz diesel car left the production line in 1965. In 1971 the one millionth Mercedes-Benz diesel car since the resumption of car production after the Second World War was produced.

In the 1970s the diesel became something of an athlete, at least in relative terms: in 1974 Mercedes-Benz presented the 240 D 3.0, the first five-cylinder passenger car and the world's most powerful series-production diesel car to date: a cubic capacity of three litres, 59 kW (80 hp) and 175 Newton metres of torque set a new standard. This power unit motivated the well-known German motoring journalist Fritz B. Busch to a top sporting achievement in 1975, when he reached a world-record speed of 253.705 km/h in his "Dieselstar". The record-breaking car was powered by a turbocharged version of the Mercedes-Benz five-cylinder diesel, which developed an output of 138 kW (187 hp) and 360 Newton metres of maximum torque.

These achievements spurred the company on: combined with a turbocharger and thereby up-rated to 140 kW (190 hp), the five-cylinder was installed in the legendary C 111 experimental vehicle and used for a record-breaking attempt on the high-speed circuit in Nardo, southern Italy, in June 1976. During this 64-hour run the C 111 II-D established a total of 16 international records over different distances and times. The records over 5000 miles, 10,000 km and 10,000 miles were also world records for any cubic capacity. Average speeds over the various distances all exceeded 250 km/h.

But the full potential of the turbodiesel had not yet been realised: just under two years later the engine was capable of 169 kW (230 hp), and in combination with a completely newly designed, aerodynamically optimised bodyshell it was used for another record-breaking run in Nardo in April 1978. In a twelve-hour period the C 111-III achieved average speeds of more than 320 km/h – with a fuel consumption of only 16 litres per 100 km.

1978: the turbocharger gives the diesel pace

This new record-breaking run was perfectly timed for the market launch of the Mercedes-Benz 300 SD Turbodiesel in May 1978. As the world's first series-production passenger car with a turbocharged diesel engine, this was also the first diesel-powered luxury car, and a further milestone in automotive development. The 300 SD Turbodiesel developed an output of 85 kW (115 hp) and was only sold in the USA.

In this especially important market for Mercedes-Benz - particularly in the luxury segment - the task of this model was to lower the so-called fleet consumption, i.e. the average fuel consumption of all the vehicles offered in the USA by a manufacturer, to avoid a punitive tax.
With a top speed of 165 km/h, the car's performance was more than adequate for US speed limits. The fuel consumption of 10.6 litres per 100 kilometres was around 30 percent lower than for the alternatively available petrol models, demonstrating the great advantages of the turbodiesel over the naturally aspirated engine: it developed a roughly 40 percent higher output with no fuel penalty. For the same reasons as the 300 SD Turbodiesel, Mercedes-Benz already began to offer the 300 CD in the USA from 1977, a diesel variant of the upper medium-class coupé. Both models met with great sales success in the USA. In Germany, an S-Class saloon or a coupé with a diesel engine were still unimaginable at the time.

1983: full encapsulation makes the 190D "whisper-quiet"

Another innovation celebrated its world premiere in the Mercedes-Benz compact class (201 series) in 1983, when the two-litre, four-cylinder 72 hp diesel in the 190 D entered the annals of the brand as the "whisper-quiet" diesel - it was fully encapsulated. Engine-generated noise was reduced by half, benefitting both the passengers and the environment. In any event the quiet diesel was easier on the nerves. In the 124 series introduced as the "medium Mercedes class" at the end of 1984, the new diesel engine generation was used in four, five and six-cylinder versions with and without turbocharging. The most powerful variant, the turbocharged six-cylinder of the 300 D Turbodiesel, generated a very respectable 105 kW (143 hp).

1984: first production car with a diesel particulate filter

In 1984 Mercedes-Benz also brought the first series-production cars with a particulate filter to market in the form of the turbodiesel models 300 D, 300 TD, 300 CD and 300 SD. These clean diesels with the first generation of the diesel particulate filter were initially marketed in California and ten other western US states – many years before the general discussion about the health hazards of particulates arose.

In Europe too, Mercedes-Benz cleaned up the diesel before legislation required it: oblique injection led to an increase in output in 1989, and particulate emissions fell by 40 percent. This was even below the stringent US limit. In the following year all Mercedes-Benz diesel passenger cars became available with exhaust gas recirculation and a diesel catalytic converter – at first as an option, and as standard from 1993.

In 1993, four-valve technology for passenger car diesel engines celebrated its world premiere in the Mercedes-Benz C and E-Class. In 1995 the first Mercedes-Benz diesel car with direct injection was launched as the E 290 Turbodiesel. Both technologies helped to lower fuel consumption and emissions, while output and torque increased - a trend that the brand was determined to continue.

Common-rail raises torque to new heights

In 1997 Mercedes-Benz opened a new, groundbreaking chapter in the history of passenger car diesel engines with trailblazing CDI technology. A combination of the newly developed high-pressure common-rail direct injection – CDI for short – and four-valve technology made 30 percent more output and 100 percent more torque possible while reducing fuel consumption and exhaust emissions. Other benefits included significantly less obtrusive combustion noise and therefore an exemplary, previously unknown level of refinement. This new injection principle became the new standard throughout the industry. There was simply nothing better.

CDI technology makes the diesel respectable in the luxury class

CDI technology also made the diesel respectable in the luxury class, for new markets and very demanding customer groups. With 184 kW (250 hp) and 560 Newton metres of torque, the S 400 CDI with its V8 engine was one of the world's most powerful diesel cars when it appeared in 2000.
Particulates were the next subject of attack: from 2003 Mercedes-Benz was the first automotive brand to offer a combination of a diesel particulate filter and the EU-4 exhaust emission standard. From 2005 Mercedes-Benz equipped all its diesel passenger cars with the maintenance-free filter, which reduces particulate emissions by up to 95 percent, as standard. And in April/May 2005 Mercedes-Benz impressively demonstrated the durability and reliability of the diesel particulate filter, as well as the performance potential and efficiency of CDI technology, even under extreme conditions: on the high-speed circuit in Laredo, Texas, three model E 320 CDI from standard production absolved a 30-day record-breaking run covering 100,000 miles (160,000 kilometres) with no problems whatsoever. Equally spectacular was the average speed of 224.8 km/h over the entire distance.

2004: BlueTEC technology makes the diesel as clean as a petrol engine

In 2004 Mercedes-Benz had already presented a further milestone achievement at the International Commercial Vehicle Show (IAA) in Hanover: the new BlueTEC technology, which enabled trucks and buses to comply with the European Union's Euro-4 and Euro-5 standards ahead of time. In 2006 the clean diesel also became available for passenger cars. The first model in series production was the E 320 BlueTEC, which made its debut on the US market in October 2006. In 2007 it was followed by the E 300 BlueTEC as the first European diesel car able to match the best petrol models in terms of emissions quality. In 2008, with the launch of the R 320 BlueTEC, the ML 320 BlueTEC and the GL 320 BlueTEC in the USA, Mercedes-Benz presented the three first SUVs in the world that were clean enough to be registered in all 50 US states.

As a modular concept for the effective reduction of fuel consumption and emissions in diesel vehicles, the BlueTEC technology developed by Mercedes-Benz comprises various coordinated technical measures that minimise untreated in-engine emissions and also ensure effective exhaust gas aftertreatment. These in-engine features include electronic control, four-valve technology, third-generation common-rail direct injection with piezoelectric injectors, turbochargers with variable geometry and exhaust gas recirculation.

Nitrogen oxide emissions drastically reduced

Oxidising catalytic converters are used to minimise emissions of carbon monoxide (CO) and unburned hydrocarbons (HC). The particulate filter, which has been standard equipment for all Mercedes-Benz diesel cars in many countries since the summer of 2005, lowers the particulate emissions to a hardly measurable level. The final goal is to achieve a drastic reduction in nitrogen oxide emissions – the only diesel exhaust gas component whose level is inherently above that of petrol engines. In the first generation of BlueTEC, which entered series production with the E 320 BlueTEC in October 2006, the nitrogen oxides were reduced by a durable NOX storage-type catalytic converter in conjunction with an SCR catalytic converter (Selective Catalytic Reduction).

For the SUV models GL 320 BlueTEC, ML 320 BlueTEC and R 320 BlueTEC, which were launched in 2008, Mercedes-Benz adapted the variant of the BlueTEC technology familiar from the commercial vehicle sector for use in passenger cars. AdBlue®, an aqueous, non-toxic urea solution is injected into the exhaust gases. This releases ammonia, which reduces up to 80 percent of the nitrogen oxides to harmless nitrogen and water in the downstream SCR catalytic converter.

OM 651: new dimension in diesel power and consumption

At the end of 2008 Mercedes-Benz presented the completely newly designed OM 651 four-cylinder diesel generation. The new engines bettered all previous figures in their segment in terms of output, torque, exhaust emissions and fuel economy. In the most powerful of three versions, the 2.2-litre four-cylinder delivers around 20 percent more output and 25 percent more torque than a comparable six-cylinder diesel engine with a cubic capacity of three litres. Nonetheless, on its debut the C 250 CDI BlueEFFICIENCY consumed only 5.2 litres of diesel per 100 kilometres, with CO2 emissions reduced to 138 g/km.

The new four-cylinder diesel engine is used in various Mercedes-Benz model series in different output classes, and achieves excellent fuel consumption figures. It can be installed either longitudinally or transversely, and is also suitable for all-wheel drive. Naturally it can also be supplemented with the innovative BlueTEC technology developed by Mercedes-Benz, and will be used as an economical internal combustion engine in BlueTEC HYBRID models.

DIESOTTO: the best of two worlds

The best attributes of the diesel and spark-ignition engine are combined in a new Mercedes-Benz concept known as DIESOTTO, the future of the internal combustion engine. As powerful and responsive as a V6 petrol engine, with the high torque and economy of a modern diesel, and extremely clean to boot. Mercedes-Benz has united these specific advantages of the two different engine types in the trailblazing DIESOTTO engine, providing an important basis for the internal combustion engine of the future. Presented in the spectacular F 700 research vehicle at the 2007 International Motor Show (IAA), this technological quantum leap has already been awarded the internationally renowned "Environment Grand Prize". The innovative technology package of the DIESOTTO engine includes direct injection, turbocharging and variable compression. The core feature of this innovation is homogeneous charge compression ignition (HCCI), a highly efficient combustion process similar to that in a diesel engine. The result is a four-cylinder with a cubic capacity of only 1.8 litres that combines the strengths of the low-emission petrol engine with the fuel economy of the diesel.

In the F 700 research vehicle, the output of 175 kW (238 hp), which is augmented by a hybrid module developing 15 kW (20 hp), and the maximum torque of 400 Nm stand in relation to a combined fuel consumption of only 5.3 litres of petrol per 100 kilometres. This corresponds to CO2 emissions of 127 grams per kilometre. These figures are achieved by a superbly equipped luxury car of the same order of size as the present S-Class. Another advantage is the very low level of nitrogen oxide emissions, thanks to homogeneous combustion at reduced reaction temperatures. Further emissions control in the DIESOTTO is by a three-way catalytic converter. Mercedes-Benz already uses features such as direct petrol injection in its current models. Until an overall solution is realised, other features will also gradually be incorporated into regular production engines.

Alternative fuels: long career with highs and lows

Before the liquid-fuelled internal combustion engine established itself firmly in the motor car at the end of the 19th century, its inventors also experimented with a number of alternative fuels in liquid, gaseous or solid form.

For example, alcohol obtained from plant material was an alternative fuel that was certainly taken seriously at the time. Around the turn of the century Daimler e.g. offered an internal combustion engine in two versions to power boats, ‑ operating on either petrol or denatured alcohol. The second variant also started off under petrol power, and was switched over to alcohol when the engine was warm. In 1905 the German army ordered a truck from Daimler-Motoren-Gesellschaft whose engine could be operated on a mixture of petrol and alcohol.

Fuels based on crude oil finally became the norm for practically all vehicles in daily use. Engineers remained open to the use of other fuels, however, as dependence on finite or not always available crude oil supplies was recognised early on. Before and during the Second World War, Germany was for example forced to resort to alternative fuels owing to lack of resources and trade restrictions. These were the glory times of the wood gasifier.

Developed by Frenchman Georges Imbert, the gasifier was fuelled with wood. Under high temperatures this formed charcoal, to which steam was added to generate a combustible gas. This was the fuel actually burned in the engine, in a similar way to petrol or diesel. Depending on the system, these gas generators could also be fired with peat, coal or coke. The range of vehicles fitted with a wood gasifier was limited to 50 to 150 kilometres per generator filling.

Engine output was also lower, and such vehicles were awkward to operate: the driver had to drain away the combustion residues every 20 to 30 kilometres. Despite these disadvantages the wood gasifier was in widespread use, as there was often no alternative during the war and in the post-war period.

Natural gas as an environmentally friendly alternative

In the 1960s public awareness of pollutant emissions and their control became a hot topic, especially in the USA. This shifted the focus of researchers and developers back to fuels, as the chosen fuel has a decisive effect on the emission characteristics of an engine. Accordingly, in the early 1970s, Mercedes-Benz began to develop and test experimental vehicles whose internal combustion engines were modified to use alternative fuels such as natural gas, alcohols and hydrogen.

1971: first natural gas powered test bus from Mercedes-Benz

In 1971 Mercedes-Benz presented OG 305 experimental bus, whose horizontally installed six-cylinder engine did not operate on diesel, but on low-cost natural gas. Both in economic and ecological terms, natural gas drive proved to be an alternative to conventional drive systems. Compared to petrol or diesel fuel, the advantages include a lower hydrocarbon content and cleaner combustion. A natural gas engine is also very quiet, and produces less CO2 compared to a diesel engine.

In 1994 the Mercedes-Benz O 405 GNG had its debut as Europe's first low-floor, natural gas powered city bus. Vans and passenger cars with natural gas drive also became available two years later: as an option, Mercedes-Benz offered the car models C 230 (202 series) and E 230 (210 series) with Natural Gas Technology (NGT) for bivalent operation with petrol and natural gas. At the 2003 International Motor Show (IAA) Mercedes-Benz presented the E 200 NGT on the basis of the E 200 KOMPRESSOR, which was the most powerful series-production saloon powered by environmentally friendly natural gas. This was likewise configured for bivalent operation with natural gas and petrol. And 2008 saw the debut of the B 170 NGT BlueEFFICIENCY as a compact car equipped with bivalent natural gas drive.

Renaissance of fuels from renewable resources since 1970

Intensive research on the use of alcohol-based fuels also recommenced at Mercedes-Benz in the 1970s – seven decades after the "spirit engine" had played a temporary role. In 1974 the company presented an experimental car with methanol drive based on the model 450 SL. The high evaporation heat of methanol cools the intake mixture and therefore leads to more efficient cylinder charging. The lower combustion chamber temperatures also considerably reduce the formation of nitrogen oxides: all in all the emission characteristics are very positive, and a 20-percent increase in output can also be expected with methanol operation. As the calorific value of methanol is only half that of petrol, twice the supply of fuel is however necessary. A car needs a tank twice the size for the same operating range. Despite these disadvantages, Mercedes-Benz systematically continued its research on alcohol-based fuels.

In 1979 large-scale trials began in Berlin as part of the "Alternative Drive Systems" project supported by the Federal Ministry of Research and Technology, and 80 alcohol-powered Mercedes-Benz research vehicles also took part. That autumn, testing began on model 208 vans which were fuelled with "M 15" (85 % premium petrol, 15 % methanol). Research cars configured for operation with pure methanol or pure ethanol were tested in the following year.

In 1990 Mercedes-Benz presented a model 300 E-24 at the Geneva Motor Show which was designed for a variable mix of methanol and petrol, and whose engine management system automatically adjusted to the mixture ratio of the two fuel components. One year later the same venue saw the debut of a "Flexible Fuel" research vehicle based on the 300 SE (140 series), whose engine management system was configured for variable, mixed methanol/petrol operation with a methanol content of 85 %.

Pioneering work on hydrogen power

Mercedes-Benz also conducted pioneering research work on hydrogen drive systems at an early stage. In 1975 the company presented its first hydrogen-powered experimental vehicle based on the L 307 minibus. The hydrogen powering a modified internal combustion engine was stored in a metal hydride tank, producing only water vapour when burned. Storing this gaseous fuel proved to be a major challenge. As a world first the researchers at Daimler-Benz opted in favour of a metal hydride reservoir, which may be regarded as the key technology for such a vehicle: it not only stores the hydrogen on board, but also optimises the system. This is because it absorbs a major part of the engine heat as the hydrogen is delivered, and this can be recovered for use elsewhere when the reservoir is refilled at a hydrogen filling-station.

In 1984 a test series with hydrogen-powered vehicles commenced in Berlin. These practical trials involved five Mercedes-Benz 280 TE cars with mixed petrol/hydrogen operation and five model 310 vans operating on hydrogen alone. Two years later Mercedes-Benz began practical trials of an experimental car powered purely by hydrogen. This vehicle was based on the model 230 E, whose 2.3-litre four-cylinder engine had been converted from petrol injection to hydrogen drive.

1994: Mercedes-Benz starts the development of fuel cell drive systems

Mercedes-Benz has carried out intensive research and testing on a fuel cell drive system for the more efficient use of hydrogen since 1994. Instead of burning this energy-rich fuel in a modified petrol engine, the fuel cell uses it to generate electrical energy. Biofuels are another field of research for alternative fuels. These are substantially carbon-neutral, as the carbon dioxide generated when they are burned was previously obtained from the atmosphere.

As early as 1992 Mercedes-Benz supported large-scale trials by taxi operators in Freiburg, who fuelled their vehicles with biodiesel (rapeseed oil methyl ester, RME) instead of diesel for a period of one year. First-generation biofuels, which include biodiesel, are a suitable short to medium-term option as admixtures to conventional fuels if negative effects on the production of foodstuffs are avoided.

In 2002 Mercedes-Benz participated in a research project with the Freiberg-based company Choren Industries GmbH for the production of high-grade fuels from biomass. These so-called BTL (Biomass-to-Liquid) fuels will gain in importance as soon as they become available from large-scale production. They make optimum use of the biomass, are free from sulphur and aromatics and are not in direct competition with the production of human and animal foods. They can also be very easily formulated for the requirements of the internal combustion engine.

Hybrid drive systems from as early as 1902

Combined or hybrid drive systems, especially the combination of an electric motor and an internal combustion engine, are a further option for the individual mobility of the future. The company already realised the first hybrid drive systems in 1902, with a special design based on the Mercedes Simplex 28 hp in which the petrol engine drove electric hub motors at the front wheels via a generator.

This pioneering powertrain system was developed by the then hardly known designer Ferdinand Porsche at "Jacob Lohmer & Co." in Vienna. He used this sporty vehicle to win the Exelberg Race in Vienna in the "Passenger Car" category, thereby impressively demonstrating the competitive potential of the world's first serial hybrid system. In 1906 Porsche moved to the Austrian Daimler-Motoren-Gesellschaft in Vienna Neustadt as technical manager, where he rapidly brought the hybrid drive system to market maturity. Under the name "Mercedes Mixte", passenger cars and buses equipped with a petrol engine and electric hub motors were offered from 1907.

The advances achieved in the field of internal combustion engine and powertrain development meant that vehicles with electric or hybrid drive remained restricted to just a few market niches. For many years to come, the future would belong to the petrol-powered car.

In 1969 the OE 302 hybrid bus marked the resumption of research and development work on electric drive systems at Mercedes-Benz. It was followed by more than 20 different concept and research vehicles with hybrid drive systems, which were produced by the in-house research function in all vehicle types right up to trucks. This produced the finding that hybrid drive saves up to 20 percent of fuel. In-depth tests particularly focused on the potential savings in urban traffic, where frequent braking/moving off and low speeds are typical.

Today's hybrids use the strengths of both drive systems to best effect

Under these conditions, modern hybrids use the synergies of the different power units particularly effectively. While the electric motor with its high torque powers the vehicle from standstill and at low speeds, the internal combustion engine drives it in its most efficient operating band. Both power units work together when peak power is required, for example when accelerating on the motorway.

Together with optimised internal combustion engines, hybrid modules are able to reduce fuel consumption even further and thereby improve environmental compatibility. To this end Mercedes-Benz has developed a modular hybrid system that allows scope for many configurations: hybrid modules in various output classes and batteries with appropriate capacities can be combined with 4 and 6-cylinder petrol and diesel engines.

The three dedicated hybrid modules develop outputs between 15 kW (20 hp) and 65 kW (88 hp). All the variants of a hybrid drive system can be realised on this basis, from the so-called mild-hybrid, which supports the internal combustion engine during acceleration and recuperates braking energy, right up to the full-hybrid which can operate under electric power alone. Another option is the plug-in hybrid, where the battery can also be recharged at a power socket to increase the "electric" operating range. The compact, disc-shaped electric motors can be accommodated in the housing of the 7G-TRONIC automatic transmission. The overall system, which also includes the new, particularly powerful lithium-ion battery, is extremely light in weight and compact.

S 400 HYBRID: first series-production hybrid from a European manufacturer

In mid-2009 Mercedes-Benz launched its first hybrid-drive passenger car in Europe - the S 400 HYBRID. This was the first hybrid vehicle by a European manufacturer, and also the world's first hybrid model with lithium-ion technology. The combined output of the V6 petrol engine and the electric motor is 220 kW (299 hp), with a combined maximum torque of 385 Newton metres. The S 400 HYBRID accelerates from zero to 100 km/h in 7.2 seconds, and reaches an electronically limited top speed of 250 km/h.

Despite this outstanding performance, the combined NEDC petrol consumption is just 7.9 litres per 100 kilometres. This means CO2 emissions of only 186 grams per kilometre, an extremely low level for this vehicle and output class. Accordingly the S 400 HYBRID achieves emission figures well below the world's most stringent limits. All the hybrid components in the S 400 HYBRID together weigh only 75 kilograms. As a result the generous interior spaciousness and the boot capacity of the S-Class are fully retained.

Compact electric motor combines several functions

The compact electric motor combines several functions: it performs the conventional duties of a starter and alternator, and also provides the ECO start/stop function. When on the move, the hybrid module supports the internal combustion engine with its "boost" effect during the fuel-intensive acceleration phase. During deceleration the electric motor acts as a generator and recovers kinetic energy by a process known as recuperation. This energy is stored in the battery and used during the next acceleration process.

Further possibilities of the modular hybrid concept from Mercedes-Benz are shown by the diesel hybrid drive of the Vision E 300 BlueTEC HYBRID. Its 15 kW electric motor supports the 150 kW (204 hp) four-cylinder diesel engine during acceleration (boost effect), and also allows driving under electric power alone. With a combined output of 165 kW (224 hp) and maximum torque of almost 600 Newton metres, the E 300 BlueTEC HYBRID consumes only 4.1 l/100 km. This corresponds to CO2 emissions of only 109 g/km. Accordingly, this extremely comfortable and effortlessly powerful premium saloon not only outstrips its direct competitors, but also smaller cars with considerably less output.

S 500 plug-in hybrid: range of 30 kilometres in electric operation

At the 2009 International Motor Show (IAA) Mercedes-Benz already showed the Vision S 500 Plug-in HYBRID as the first "three litres per 100 kilometres" car in the luxury class. Introduction of this innovative plug-in hybrid drive system, which allows purely electric driving with a range of up to 30 kilometres, is already planned for the next generation of the S-Class. The drive system consists of three main components: a powerful V6 petrol engine with next-generation direct petrol injection, a hybrid module delivering around 44 kW (60 hp) and a lithium-ion battery with a capacity of more than 10 kWh.

Thanks to its efficient drive system and the CO2 bonus for battery-electric operation, the S 500 Plug-in HYBRID achieves a certificated fuel consumption of just 3.2 litres of petrol per 100 kilometres, corresponding to CO2 emissions of only 74 grams per kilometre. In this way the near-series technology platform demonstrates the future potentials of coming S-Class generations. Because the S 500 Plug-in HYBRID stands for all the strengths for which the S-Class is well-known: first-class comfort, outstanding safety and superior performance.

F 800 Style with variable vehicle architecture

The Mercedes-Benz F 800 Style research vehicle provides a further outlook on the luxury saloon car of the future. This has the world's first variable vehicle architecture for large saloons, allowing various alternative drive systems to be installed: the F 800 Style Plug-in HYBRID version is equipped with a modified drive system from the S 500 Plug-in HYBRID, and even more efficient in operation. Indeed, this research vehicle achieves a provisionally certificated petrol consumption of only 2.9 litres per 100 kilometres. That corresponds to CO2 emissions of just 68 grams per kilometre.

Battery-electric drive: "Mercedes Mixte" shows new possibilities

In the early years of the motor car, the later predominance of the internal combustion engine, which is now taken for granted, was not a certainty. Alternatives included electric drive, and in some segments even steam power. This variety of systems was also taken into account by Daimler-Motoren-Gesellschaft, when it equipped a Mercedes-Simplex 28 hp with a hybrid drive system in 1902. The petrol engine powered electric hub motors at the front wheels via a generator. This drive concept entered regular production with the Austrian Daimler-Motoren-Gesellschaft at the end of 1906, which marketed passenger cars and buses under the name "Mercedes Mixte".

The model range also included "Mercedes Electrique" vehicles, which were purely electrically powered. Instead of the petrol engine, a powerful battery fed the electric hub motors which were installed at the front or rear wheels, depending on the vehicle model. The "German Mercedes Sales Company" was fulsome in its advertising for the Mercedes Electrique: "The safest, quietest and most modern electric town car", an early reference to the urban operating environment. Sure enough, these electric vehicles with wheel hub motors were mainly purchased by grateful town-dwellers.

Passenger cars and commercial vehicles with electric drive

In addition to passenger cars, the product range included trucks, buses, ambulances and above all fire service vehicles. In 1908, the Berlin fire service took Germany's very first electrically powered automotive fire tenders into service with four vehicles based on "Mercedes Electrique" chassis. The advantages of the electric vehicles were their constant readiness to start and relatively inexpensive operation and maintenance. This is because the use of wheel hub motors made mechanical power transmission components such as a gearbox, clutch and drive chains unnecessary.

The energy of the heavy lead/acid accumulators was however soon exhausted, which limited the range of the vehicles. In these early years of the motor car, the long recharging times also prevented them from competing effectively with vehicles powered by an internal combustion engine in the longer term.

Since 1960: more than 600 electric drive patents

It was not until the end of the 1960s that the electric car was given renewed attention. This was when Mercedes-Benz began intensive research on new solutions for locally emission-free driving, which is why the company now has enormous experience in the field of electric drive systems. Its employees have registered more than 600 patents covering battery-electric vehicles since then.

In 1972 the electrically powered LE 306 van followed an innovative approach in a bid to overcome the limitations on operating range: accessible via a side flap between the axles, the battery pack located under the load platform could be quickly and easily pulled out on one side while a freshly charged pack was inserted on the other. Depending on driving style, a battery charge was sufficient for around 50 kilometres. The electric motor delivered an output of 35 to 56 kilowatts, and maximum speed was 80 km/h. In subsequent years 89 electric vans taking part in practical trials covered a total of around 2.9 million kilometres. In November 1975 a summary assessment recommended the system for urban distribution vehicles covering less than 100 kilometres each day.

The battery-exchange system was developed further for the succeeding model 307 E in 1980: a lifting mechanism incorporated into the battery holder enabled the battery to be removed downwards with the help of conventional jacking tools. As another progressive feature, the braking energy could be fed back to the battery. The main development aim was to reduce production and operating costs.

Battery-electric vans in day-to-day trials

The control technology was simplified, and operating the vehicle on a day-to-day basis was no different from a van with an internal combustion engine. The load compartment was exactly the same size as that of the standard van with a conventional engine, and the payload was 1.5 tonnes. In 1983 the German postal service took 22 vehicles of this type into operation for practical trials. Energy costs were however almost twice as high as for comparable diesel vehicles.

Electric drive: car testing resumed at Mercedes-Benz since 1982

In early 1982 Mercedes-Benz began testing electric drive systems in passenger cars. The research vehicle was based on a 123-series Estate model. The DC motor installed in place of the conventional engine had a continuous output of 25 kW (34 hp) and drove the rear wheels via an automatic transmission and propeller shaft. Also integrated into the drive unit was a 10 kW (14 hp) two-cylinder internal combustion engine with noise encapsulation, which recharged the battery as a backup system when required.

The modified load compartment housed a newly designed nickel/iron battery weighing 600 kilograms, which the researchers expected to deliver twice the energy by weight compared to a lead/acid battery. In terms of ride comfort and equipment the vehicle corresponded to the standard specification for this series, however the load compartment space was restricted owing to the battery. The operating range was around 100 kilometres.

The Mercedes-Benz 190 (201 series) provided the basis for the next generation of electrically powered test vehicles, which was presented to the public in 1990. These cars were used to test various electric drive configurations, and above all different battery systems. By virtue of their high energy density, it was particularly the sodium/sulphur battery and the sodium/nickel chloride battery, also known as the ZEBRA battery, that appeared to have future potential.

Unfortunately the electrochemical reaction only took place from a temperature of 260 to 350 degrees Celsius, which meant that the hermetically sealed and thermally insulated battery cells had to be electrically heated.

ZEBRA battery with good longevity but a high space requirement

The ZEBRA battery had around four times the performance of a conventional lead/acid accumulator, and also a longer operating life. In practical driving tests some of these Mercedes-Benz research vehicles achieved mileages of more than 100,000 kilometres with one battery, demonstrating the practical suitability of the concept. One disadvantage was the still very considerable space required for the battery, which filled the entire boot and projected onto the rear seat unit, which meant that the first generation of the electric 190 could only seat three occupants. In 1991 Mercedes-Benz presented a new drive concept with an electric research car based on the model 190, in which two electric motors each delivering a peak output of 16 kW (22 hp) directly drove the rear wheels. Thanks to the high torque over the entire rpm range, no transmission was necessary, eliminating the powertrain and the associated power losses. The compact and lightweight construction created space and saved weight. Energy was supplied by two smaller batteries located under the bonnet and in the boot, leaving the rear seat available for use.
1992: major project with electric vehicles in Rügen

In 1992 a four-year demonstration project commenced on the island of Rügen

to test electric vehicles and obtain findings on their behaviour under practical conditions. Mercedes-Benz provided ten test vehicles based on the model 190 and ten MB 100 vans with various electric motor and battery combinations. The vehicles were recharged at normal power sockets, and also at special recharging stations which obtained part of their energy from solar power.

Over the next few years more than 60 research vehicles with ZEBRA high-energy batteries were built. In 1998 an A-Class (range 160 to 200 kilometres with an electronically limited top speed of 130 km/h) was presented, which was specifically chosen for this application. Its sandwich-floor design provided the ideal installation space for alternative drive systems, and showed that these could also be accommodated in such a compact vehicle. The interior remained unrestricted, and the luggage capacity remained fully usable. This principle is also highly successful in the present A-Class E-CELL, small-series production of which commenced in autumn 2010.

Battery technology: key to the success of the electric car

The history of electric vehicle research at Mercedes-Benz has shown clearly that the performance of the entire electrical system depends on the battery, starting with its storage capacity. In addition it must have a long operating life and show a high level of crash safety, as well as being recyclable. All these conditions are met by the new lithium-ion battery specifically developed for use in vehicles.

In 2008 Mercedes-Benz became the world's first manufacturer to render lithium-ion technology, which was previously mainly used for consumer electronics, suitable for the requirements of a passenger car, commencing series production in the S 400 HYBRID in 2009. The Stuttgart-based company holds a total of 25 patents which have made this important technological breakthrough possible.

The major advantages over conventional batteries are the higher storage capacity and efficiency, together with more compact dimensions and lower weight. Compared to a nickel/ metal hybrid battery, this innovative lithium-ion technology allows more than three times the operating range for half the weight. The innovative lithium-ion flat cell has great potential for further advances in efficiency. Other advantages of this technology include a higher energy density with an even more compact construction. In parallel with this, the company is creating the conditions for industrialised production of lithium-ion batteries, the goal being to commence production in Germany in 2012. This will ensure that these previously very expensive batteries can be produced at lower cost and in adequate quantities.

2010: A-Class E-CELL achieves a range of over 200 km

All this provided the basis for the next step: in autumn 2010 Mercedes-Benz is putting its first battery-electric car assembled under series-production conditions onto the roads - the A-Class E-CELL. This family five-seater based on the five-door version of the A-Class (169 series) is fully suitable for day-to-day motoring, and provides the same generous and flexibly usable interior and luggage space. No compromises are necessary with respect to spaciousness and flexibility, as the batteries are neatly and safely accommodated within the sandwich floor, where they also lower the centre of gravity.

The two highly-efficient lithium-ion batteries allow an operating range of more than 200 km (NEDC), which means that the A-Class E-CELL sets the benchmark in this segment. Adequate performance is assured by a quiet, locally emission-free electric motor with a peak output of 70 kW (95 hp) and a high torque of 290 Nm. The A-Class E-CELL is produced at the home plant of the A-Class in Rastatt. The initial production run will be a small series of around 500 units, which will be rented to selected customers for a period or four years (or 60,000 kilometres).

Electric drive with the fuel cell: Mercedes leads the field

The alternative to battery-electric drive is the electric drive system using energy obtained from fuel cells. As early as 1994, Mercedes-Benz presented its first fuel cell powered car - the NECAR (New Electric Car) - and demonstrated that this technology can be used to power vehicles. This innovative technology for emission-free mobility completely filled the load compartment of the model MB 100 van used as a research vehicle. Mercedes-Benz went on to develop further, more compact variations on fuel cell technology in subsequent NECAR vehicles based on the V-Class and A-Class.

In 1999 - in the NECAR 4 - the researchers successfully managed to accommodate a 70 kW (95 hp) electric fuel cell drive system including its fuelling system entirely within the sandwich floor of the A-Class. Accordingly this Zero Emission Vehicle had adequate space for five occupants and their luggage. The research vehicle initially generated its onboard power using liquid hydrogen, and in a later development stage with compressed hydrogen, achieving an operating range of 200 kilometres. This technology later established itself for the first fuel cell vehicle built under series production conditions.

Thanks to a newly developed coolant based on ethylene glycol, the drive system was now also suitable for frosty conditions, with reliable starting even in icy winter weather. As in earlier diesel engines, only a short heating-up time is required before the operating temperature is reached.

On this basis a small series of 60 A-Class F-CELL cars was produced in 2003/2004 and supplied to selected customers for trials under practical conditions. Here too, the complete fuel cell system was accommodated within the sandwich floor.

2004: world's largest fuel cell test fleet

In 2004, with these 60 A-Class F-CELL passenger cars and 36 Citaro F-CELL city buses, Mercedes-Benz had the world's largest test fleet of fuel cell powered vehicles. Meanwhile around 100 cars, buses and vans have performed successfully in customer hands, covering a total of more than 4.5 million kilometres by the end of 2008. 180 registered patents in the field of fuel cell technology are impressive proof of the company's pioneering achievement.

The experience gained with the A-Class F-CELL was put to use when production of the B-Class F-CELL commenced in autumn 2009, the first hydrogen-fuelled fuel cell vehicle built under series production conditions. The B-Class F-CELL is equipped with the latest-generation fuel cell drive system, with compressed hydrogen and 700-bar technology. The electric motor develops a peak output of 100 kW (136 hp) and maximum torque of 320 Newton metres. Accordingly the B‑Class F-CELL matches the performance of the B 200, its equivalent with a two-litre petrol engine.

Fuel cell: long range and short refuelling time

Mercedes-Benz considers the fuel cell to be one of the key technologies for the emission-free motoring of the future. In the longer term it provides the best conditions for sustainable, uncompromisingly environmentally friendly mobility, also over long distances. Thanks to their longer range and short refuelling times, fuel cell cars are also suitable for long journeys, as they generate their own electric power onboard using a chemical reaction between hydrogen and oxygen. There are no harmful emissions, only pure water vapour. Moreover, a fuel cell drive system is inherently twice as efficient as an internal combustion engine.

E-Drive modular system allows a wide range of applications

As for hybrid drive configurations, Mercedes-Benz has developed a modular system for electric drive. This allows the efficient use of common parts in all electric vehicles.

With the near-series Concept BlueZERO in 2009, Mercedes-Benz showed the way towards environmentally compatible electro-mobility with no limitations to interior space and payload. The intelligent, modular concept based on a single vehicle architecture allows scope for three models with different drive configurations. These take the different requirements of users into account. Depending on the intended type of operation, there are different technologies that allow different operating ranges:

- The BlueZERO E-CELL with purely battery-electric drive and a range of up to 200 kilometres,
- The BlueZERO F-CELL (fuel cell), which generates its own onboard electric power and has a range of well over 400 kilometres using electric drive, and
- The BlueZERO E-CELL PLUS with electric drive and an additional internal combustion engine as a power generator (range extender). This version has an overall range of up to 600 kilometres and can cover a distance of up to 100 kilometres using electric drive alone.

The three BlueZERO variants were realised on the basis of the sandwich-floor

architecture that Mercedes-Benz already introduced in the A-Class in 1997 and later adopted for the B-Class. The major drive components can be installed in the vehicle's underbody. This means that Mercedes-Benz already possesses all the key technologies for electric cars that are fully suitable for day-to-day motoring. All three BlueZERO variants share major technical components, while design and vehicle dimensions are identical. The only 4.22-metre long BlueZERO models combine compact exterior dimensions with a generous and flexible interior and luggage space. Five seats, a payload of around 450 kg and more than 500 litres of luggage capacity make these cars fully suitable for everyday driving.

Sandwich floor has major advantages for electric vehicles

The BlueZERO concept has decisive advantages over electric cars based on conventional vehicle platforms: thanks to integration of the batteries or energy generators within the spacious sandwich floor, interior spaciousness and good all-round visibility are fully retained. Installing the powertrain technology within the sandwich floor ensures a low centre of gravity and extremely safe, agile handling. Crash safety is also at the high level to be expected of a Mercedes, thanks to the sandwich concept and accommodation of most major drive components between the axles.

All the major components of battery and fuel cell drive systems are suitable for modularisation, from the electric motor and transmission to the battery and the high-voltage safety concept, and right up to high-voltage wiring and software modules.

In the case of fuel cell vehicles, specific components such as stacks and hydrogen tanks can be standardised for very different vehicles - simply by varying their number as required. For example, the Citaro FuelCELL Hybrid urban bus is equipped with two fuel cell systems of the same type that is used in the B-Class F-CELL.

F 800 Style: highly efficient drive system for premium cars

With the F 800 Style research vehicle presented at the beginning of 2010, Mercedes-Benz provided a further outlook on the future of the premium car. This five-seater luxury saloon combines highly efficient drive technologies with innovative comfort and safety features. Its newly developed, variable drive architecture is a world first for large saloons. It is suitable for both electric operation with a fuel cell, which allows an operating range of around 600 kilometres, and for use as a plug-in hybrid with a total operating range of around 700 kilometres which can cover up to 30 kilometres under electric power alone. Both variants of the F 800 Style therefore provide locally emission-free mobility at a premium level combined with full day-to-day suitability.

In the hybrid version, Mercedes-Benz engineers gave particular attention to further development of purely electric driving in the urban environment. The drive unit consists of an approx. 220 kW (300 hp) V6 petrol engine with next-generation direct injection and an approx. 80 kW (109 hp) hybrid module. The lithium-ion battery with a capacity of around 10 kWh is located beneath the rear seat unit to save space and provide the best possible protection. It can be recharged at charging stations or household sockets, and allows a purely electric operating range of up to 30 kilometres.

Hybrid module fully integrated into 7G-TRONIC

The high-output, high-torque hybrid module is fully integrated into the housing of the seven-speed 7G-TRONIC automatic transmission. Its high power reserves make a top speed of 120 km/h possible in electric mode – enough even for the requirements of inter-urban traffic. The total output of the hybrid drive system is around 300 kW (409 hp), guaranteeing performance at sports car level (0–100 km/h in 4.8 s, top speed 250 km/h). Thanks to the efficient drive system and a CO2 bonus for battery-electric operation, the F 800 Style nonetheless achieves a certificated petrol consumption of only 2.9 litres per 100 kilometres. This results in extremely low CO2 emissions of just 68 grams per kilometre. With its highly efficient drive system, the F 800 Style is another major step towards the market maturity of the plug-in hybrid that Mercedes-Benz will already be taking into series production with the next generation of the S-Class.

F 800 Style with fuel cell drive as an alternative

The F 800 Style with electric drive based on fuel cell technology also offers environmentally clean driving enjoyment. The approx. 100 kW (136 hp) electric motor develops a powerful torque of around 290 Nm. The F 800 Style characteristically features innovations that have already reached a near-series stage of development maturity.

The flexibly usable components of the fuel-cell drive are taken from the E-Drive modular system which Mercedes-Benz has developed for a variety of different electric vehicles, and they are already being installed in a small series of the B-Class F-CELL. They are suitable for a variety of drive configurations, including the F 800 Style, which has rear-wheel drive in contrast to the B-Class F-CELL. The new Mercedes-Benz research vehicle has the fuel cell located in the front, while the compact electric motor is installed near the rear axle. The lithium-ion battery is positioned behind the rear seats where, like the four hydrogen tanks, it has the maximum possible protection against the effects of accidents. Two of the tanks are located in the transmission tunnel, while the other two are beneath the rear seat.

Comprehensive sustainability has been the focus at Mercedes-Benz for decades

One of the principles enshrined in the corporate environmental guidelines is that the environmental effects of the products and activities are to be considered over the entire lifecycle, and continuously reduced. The comprehensive approach taken by Mercedes-Benz therefore includes the entire research and development process, includes suppliers and logistics, encompasses production and sales/distribution, and takes both the operation and eventual recycling of all models into account. It is also a tradition in the company to continuously develop progressive, effective and reliable environmental technologies. These include all-embracing improvements with respect to weight, aerodynamics, rolling resistance, energy management and powertrain engineering. Around 18,800 personnel work in the company's research and development departments around the world. One of the major focuses of their work is the minimisation of emissions and energy consumption during product production, operation and recycling.

Environmentally compatible product development

The ecological effects of a product are substantially considered in the early development phase. The earlier environmentally compatible product development is integrated into the development process, the more effectively the environmental effects can be minimised. Later corrections can only be made at great expense.

Continuous improvements to the environmental compatibility of Mercedes-Benz vehicles are therefore defined in the respective specifications during development as a so-called "Design for Environment" process. Special "DfE" teams with engineers from various disciplines ensure that the defined environmental goals are met, for example in the areas of eco-balance, dismantling and recycling, materials and process engineering, design and production.

Lowering emissions and reducing the consumption of resources over the entire lifecycle is the decisive factor when it comes to improving the environmental compatibility of a vehicle. Environmentally compatible product development therefore starts with the selection of suitable raw and processed materials, and ends with recycling-friendly design and production that allows subsequent reuse. Intelligently conceived dismantling and recycling concepts mean that nowadays, fewer and fewer old parts need to be disposed of.

Cooperation with suppliers is based on clear mutual expectations and obligations. These are aimed at meeting ecological goals, and are defined in the "Sustainability guidelines for suppliers".

Environmental protection through intelligent logistics

Delivery traffic between, to and from the production locations also has environmental effects. Harmful emissions from transport activities are reduced by using rail and shipping connections. Supplier parks are also increasingly located in the immediate vicinity of the production plants. In 2004, for example, the Untertürkheim plant took a logistics centre into operation from which almost 69,000 tonnes of assemblies and parts are transported by environmentally friendly rail and shipping routes each year. As a result around 4000 tonnes of CO2 emissions were avoided in 2009.

Environmental protection in production

Intelligent production and process engineering also drive innovation in environmental protection. The most important areas of action are climate protection, clean air and the conservation of resources. This specifically means lowering direct and indirect CO2 emissions, reducing the use of solvents, avoiding waste and using resources more efficiently. All the plants are certificated according to the currently most stringent international environmental standard, ISO 14001. This means that environmental protection is systematically enshrined in the management processes, and environmental aspects are given equal weight in all day-to-day activities and corporate policy decisions.

The International Standards Organisation (ISO) only grants its ISO 14001 seal of approval to businesses and facilities that are able to continuously reduce the effects of their activities on the environment. The certificate is granted after an intensive examination by recognised organisations, which is then regularly repeated.

Over and above the certification of environmental management systems according to ISO 14001, all the German production locations voluntarily participate in the European eco-audit system EMAS. Validated by independent experts, the environmental reports issued by each location cover all the important environmental data, targets, measures and implementation statuses.

Climate protection has the highest priority

Climate protection has the highest priority within the production-related environmental protection measures. Improved use of waste heat, more efficient air compression and ventilation techniques, and demand-controlled heating, lighting and machine operation achieve considerable energy savings. The energy mix is also changing dramatically towards natural gas and renewable alternatives. In 2009 alone, the total CO2 emissions of all the plants fell by almost 16 percent.
The successes achieved over the decades are impressive: for example, the engine plant in Bad Cannstatt with its closed-circuit processes is now almost entirely free from waste water and materials, and its air pollution figures fall well below the legally prescribed limits.

Ultra-modern photovoltaic facility in Bad Cannstatt

In combination with an ultra-modern photovoltaic facility, waste heat reutilisation and recycling installations were already setting new standards in Bad Cannstatt in the 1990s. The solar cell complex with a total area of 5000 sq. m. generates 350,000 kWh of power each year. This would cover the energy needs of more than 120 households. The generated power is fed directly into the plants power network. In 2009 the photovoltaic surface areas on the roofs of every plant building increased to a total of 35,000 sq. m., raising the generated energy to 4.18 million kWh.

In its engine production the plant uses the award-winning principle of micro-lubrication. In this process, minute quantities of lubricant are mixed with cooled air and used in place of the usual cooling lubricants. Thanks to this new process, only a tiny fraction of the cooling lubricant quantities formerly used is needed. As these substances are produced from crude oil, and must undergo energy-intensive, costly reprocessing, innovative micro-lubrication makes a major contribution to environmental protection. In addition, a true eco-paradise has come into being on the periphery of the production site. The concept of creating the "Neckarkiesbank" came about in cooperation with environmental and nature conservation associations.

In this artificially created wetland covering an area of 4000 sq. m., with its characteristic heat sinks and a warm microclimate, 40 recognised species of wild bees have now found a new home.
Painting technology in car production has also reached such a high standard that only very small further reductions in emissions are possible. Since the introduction of water-based paints in the 1990s, solvent emissions in the passenger car plants have been reduced by around 70 percent.

Reprocessing and reusing raw and auxiliary materials as well as service fluids has also been a matter of course in the plants for many years. The company relies on innovative technical processes and environmentally oriented production planning to try and ensure that waste is not generated in the first place. At the Untertürkheim location, for example, a process has been developed which separates the machining oil from the waste water after parts are cleaned, and reprocesses this so that it can be directly reused.

Environmental protection in the dealership

The corporate environmental guidelines also provide the strategic framework for environmental protection in the worldwide sales organisations. In Germany the Mercedes-Benz sales organisation (MBVD) operates an active environmental management system on this basis that includes dealers and the company-owned sales & service outlets. Recycling according to the Mercedes Recycling System (MeRSy) has been well-established in these outlets for almost 15 years. It ensures that materials are professionally collected, reused or reprocessed according to the requirements. Each year MBVD collects and reuses more than 30,000 tonnes of waste segregated into 35 types. These programmes are producing results: since 2003, for example, water consumption has fallen by around 12,000 cubic metres or 9.4 percent thanks to greater use of vehicle washing facilities that use a closed water circuit. Considerable savings have also been made in the energy sector for many years, and for widespread implementation a concept for the "energy-efficient dealership" is currently
being developed.

Specific measures for environmentally compatible vehicle operation

Over the entire lifecycle of a passenger car, around 80 percent of the primary energy consumption and also the CO2 emissions occur during the operating phase – the purpose for which the car was built in the first place. Since 2009, Mercedes-Benz has consolidated extensive measures designed to save fuel in petrol and diesel models, and therefore reduce environmental effects during a vehicle's operation, into BlueEFFICIENCY packages which are included as standard in numerous Mercedes-Benz cars. This environmental label enables the customer to see at first glance which model currently offers the best environmental standard. In addition, BlueEFFICIENCY describes all the other environment-related technological developments that contribute to sustainable, emission-free mobility, for example hybrid or electric drive systems. Depending on the model series, the tailor-made packages for series-production models feature various in-engine measures and a combination of different technologies used to save body weight, including a weight-optimised windscreen of laminated glass and lightweight wheels.

The BlueEFFICIENCY package also includes low-friction tyres with reduced rolling resistance and aerodynamic improvements designed to reduce drag, for example a lowered suspension, modified engine compartment and underbody panels, partial masking of the radiator grille, redesigned exterior mirror housings and smooth underbody panelling.

BlueEFFICIENCY measures also include the ECO start/stop function as a preliminary stage to hybridisation. This makes further fuel savings of up to nine percent possible in city traffic. The system is already available in numerous models, and is gradually being introduced in all Mercedes-Benz model series. Demand-related control of the peripheral units and the air conditioning compressor also helps to lower fuel consumption, as does reducing friction losses. In the BlueEFFICIENCY models of the C-Class and E-Class, the power steering is controlled according to demand to save energy. The engine needs to devote less energy to driving the steering servo pump.

40-percent lower fleet CO2 emissions since 1995

All in all, and depending on the model series, BlueEFFICIENCY measures reduce CO2 emissions by up to 30 percent. By the end of 2010, 95 Mercedes-Benz passenger and van models will feature BlueEFFICIENCY technologies. In Europe, Mercedes-Benz Cars has already been able to reduce fleet CO2 emissions by around 30 percent between 1995 and the end of 2009. The goal is to reduce the CO2 emissions of the new car fleet in Europe to below 140 grams per kilometre by 2012 – corresponding to a reduction of almost 40 percent since 1995.

Quite apart from the vehicle-related improvements, the driver himself has a decisive influence over fuel consumption. Studies have shown that over the longer term, a driver is able to make up to 10 percent fuel savings if he obeys the rules of economical, anticipatory driving. Making drivers aware of these potential savings is the aim of the Mercedes-Benz Eco driver training scheme.

The driver is assisted by a newly developed gearshift display in the cockpit, which tells him when he should change gear. As a further new feature in addition to the shift recommendation function, this "onboard efficiency trainer" indicates the current fuel consumption. This directly enables the driver to monitor the efficiency of his driving style. The fuel consumption display is gradually being introduced in all Mercedes-Benz models.

End of life: high recycling rate conserves the environment

Environmentally compatible and recycling-friendly design has a high level of importance in the development process. One example is the use of segregated materials for the bumpers and underbody panels of all Mercedes-Benz models. This allows easy dismantling and efficient materials recycling.

The requirements for the recycling of end-of-life vehicles are extensive: since 1993 the authorised workshops have been required to collect packaging materials, workshop waste materials, used vehicle and warranty parts and service fluids for reuse. The system is now established in Belgium, Germany, Luxembourg, the Netherlands, Austria, Switzerland and Spain. In 2009 a total of 31,064 tonnes of used parts were collected for further use. Around 1.1 million litres of coolant and 807,000 litres of brake fluid were reprocessed.

Since 1996 the Mercedes-Benz Used Parts Centre has made an important contribution to the recycling concept by the resale of tested and certificated used components. To date it has dismantled more than 15,000 vehicles bearing the Mercedes star, selling their parts for further use and properly disposing of residual materials. The warehouse has a regular stock of around 370,000 parts.

- Efficient take-back and recycling network with more than 200 return points in Germany alone since 2002
- Free take-back of all end-of-life vehicles since January 2007
- Prohibition of the heavy metals lead, hexavalent chromium, mercury and cadmium
- Detailed dismantling information is electronically available to all ELV recyclers via the International Dismantling Information System (IDIS).
- Environmental certificate to the ISO standard for Mercedes-Benz cars

Mercedes-Benz is the world's only car brand to have been awarded an environmental certificate according to ISO 14062 by the independent experts of TÜV Süd. This environmental certificate is based on a complete Life Cycle Assessment. It takes around 40,000 individual processes into consideration, and covers the entire vehicle lifecycle over a total mileage of up to 250,000 kilometres, ‑ depending on model.

In 2005 the S-Class was the world's first car to be awarded this demanding environmental certification, confirming compliance with all the requirements. With the C-Class Saloon (2007), the C-Class Estate (2008), the new-generation A‑Class and B-Class (both 2008), the GLK and the E-Class (both 2009), as well as the S 400 HYBRID (2010), no less than eight Mercedes-Benz car model series have now been examined and verified by independent specialists at TÜV Süd Management Service GmbH. "Many of the solutions examined can be regarded as exemplary", the TÜV experts stated in their audit report. The certificates also illustrate the great advances that have been achieved versus the relevant preceding or comparable models.

Environmental balance using the example of the Mercedes-Benz E-Class

Considering the entire lifecycle of the E-Class, the new 212-series model produces 14 percent fewer CO2 emissions than its predecessor at the time of market launch in 2002. With respect to total nitrogen oxide emissions the E-Class is even more advantageous, as the reduction compared to the preceding model is no less than 20 percent. This is primarily due to the new engines. The overall energy balance is also positive, for over the entire lifecycle is has been possible to make 13% primary energy savings versus the preceding model launched in 2002. This corresponds to the energy contained in 3200 litres of petrol.

The E-Class already meets the recycling quota of 95 percent by weight according to the ISO 22628 calculation model, which will only become mandatory from 1 January 2015.

Even during the development phase, great attention was already paid to materials segregation and ease of disassembly for certain thermoplastic components such as the bumpers, wheel arches and the side member, underbody and engine compartment claddings. All in all, 43 components with a total weight of 41.5 kilograms are made from recycled, high-quality plastics. This is an increase of 80 percent in the weight of approved recycled components compared to the preceding model.

Components made from recycled and renewable raw materials

Another aim was to obtain recycled materials from vehicle-related waste flows as far as possible, so as to create closed loops. Example: the recycled material used for the front wheel arches consists of reprocessed vehicle components such as the housings of starter batteries and bumper claddings from the Mercedes-Benz Recycling System, as well as waste material from cockpit production.

44 components in the E-Class with a total weight of around 21 kilograms are produced using natural materials. The boot flooring is made from a cellular cardboard structure, for example, and for fuel tank ventilation the engineers at Mercedes have also opted for a natural material. Coke obtained from olives is used as an activated charcoal filter. This open-pored material absorbs hydrocarbon emissions, and the filter regenerates itself automatically during vehicle operation.

Renewable materials also play an important part in the production of the fabric seat upholstery, which contains 15 percent pure sheep's wool. Wool has significant comfort advantages over synthetic fibres: it not only has very good electrostatic properties, but is also better at absorbing moisture and has a positive effect on climatic seating comfort in high temperatures.

E-Class: in the lead for efficiency and environmental compatibility

Three completely newly developed four-cylinder diesel engines secure a leading position for the E-Class where environmental compatibility in day-to-day operations is concerned. These engines feature latest-generation common-rail direct injection, fast piezoelectric injectors and efficient exhaust gas recirculation.

Mercedes-Benz equips the BlueEFFICIENCY petrol models E 200 CGI and E 250 CGI with the newly developed four-cylinder direct-injection engine with a displacement of 1.8 litres, turbocharging and variable intake and exhaust camshafts.

The low Cd value of 0.25 – which makes the E-Class the world's most aerodynamically efficient luxury saloon – also helps to lower fuel consumption. This value is four percent lower than that of the preceding model, which in practical terms means that at a motorway speed of 130 km/h, there is a fuel saving of around 0.25 litres per 100 kilometres. The aerodynamics have e.g. been improved by an automatically controlled radiator shutter, which regulates the airflow into the engine compartment as required.

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