Mercedes Benz

Daimler AG is the first manufacturer to have tested plug-in vehicles since as early as December 2005, in Los Angeles (California/USA).

More economical, light and powerful - the second-generation Sprinter Plug-In Hybrid represents a major step forward to a low-emissions future that conserves natural resources. Four years after presentation of the first hybrid Sprinter, and just under two years after the Sprinter Plug-In Hybrid with a diesel engine entered its customer trials, the imminent large-scale customer trials will bring series production another step closer.

From summer this year eleven vehicles will enter customer trials in Los Angeles, Chicago, Detroit and Washington DC. In parallel with this, two further Sprinter Plug-In Hybrids will undergo trials in Germany. This fleet consists of panel vans and crewbuses, will be used in delivery, service and shuttle operations and therefore covers a variety of operating profiles. It is also the world's largest test fleet of hybrid-drive vans.

The new Sprinter Plug-In Hybrid represents a great technical advance compared to the the first hybrid vehicles based on the preceding generation of the Sprinter. It is powered by a parallel hybrid system with an electric motor between the internal combustion engine and the automatic transmission.

The architecture retains an unmodified petrol tank with a capacity of 100 l between the axles. A pack of lithium-ion batteries is installed immediately behind the rear axle. While providing a comparable capacity, this battery technology weighs only 175 kg, i.e. half as much as the nickel/metal hydride batteries used in the first hybrid generation.

Thanks to this innovative battery technology, the kerb weight of the Sprinter Plug-In Hybrid panel van with the standard 3665 mm wheelbase is just under 2.2 t. Given a permissible gross vehicle weight of 3.88 t, and including the driver, this leaves a highly respectable payload of around 1.6 t, which is only slightly less than that of the Sprinter with a conventional diesel engine.

At the same time this battery technology occupies considerably less space: in contrast to the first-generation hybrid vans, the load compartment of the new Sprinter Plug-In Hybrid can now be used to the full. The battery pack is cooled. Other special features of the new Sprinter Plug-In Hybrid include electrically powered ancillary units such as the steering servo pump, brake servo unit and air conditioning compressor. This is a precondition for vehicle operation under electric power alone.

The batteries are recharged in three ways: by the internal combustion engine when on the move, by energy recuperation when braking and via a cable connected to the mains ("plug-in") overnight or during breaks. For this purpose the Sprinter has a power socket on the front right-hand side, above the wheel arch.

The Sprinter Plug-In Hybrid also delivers an outstanding combination of environmental compatibility and performance. Depending on the type of operation, it is able to cover 30 km at a stretch on electric power alone, which means that the Sprinter Plug-In Hybrid can operate entirely without emissions in environmentally sensitive areas such as inner cities and pedestrian precincts. And this not only means without exhaust emissions, as the Sprinter operates practically silently under electric power. Without being recharged from the mains, it is e.g. able to cross the entire metropolitan area of Hamburg or operate around the inner city under electric power alone for around one hour – not even counting delivery stops.

The potential fuel savings are no less astonishing. During a practical operational test conducted with the courier service FedEx over a very demanding inner-city route in Paris, fuel consumption fell by 40 percent to just 10.1 l per 100 km compared to diesel operation alone. 62 percent of the journey was absolved under electric power only. The developers expect a similar reduction in fuel consumption during the latest trials in the USA. Their realistic assumptions are in part based on earlier trials of the first-generation Sprinter Plug-In Hybrid in New York: in that case fuel consumption fell by 36 percent compared to conventional operation when one third of the route was covered under electric power alone.

The Sprinter Plug-In Hybrid achieves these outstanding results thanks to an intelligent operating strategy. When waiting at traffic lights, for example, the van is completely silent because both power units are switched off. It then moves off with barely a whisper under electric power. When powerful acceleration is required, both the electric motor and the internal combustion engine are in operation. At constant speeds the power units operate according to the power requirements. The internal combustion engine is switched off during braking, while the electric motor acts as a generator and charges the batteries.

With this strategy the electric power unit fulfils two functions: on the one hand it allows emissions-free operation in especially environmentally sensitive areas, and on the other it assists the internal combustion engine when high performance is required, enabling it to remain in a fuel-efficient operating range.

The drive package delivers an impressive performance. The electric motor develops a sustained output of 42 kW and 182 Nm of torque. The maximum output for short bursts is 71 kW, with a maximum torque of 280 Nm - which means that the electric motor alone is able to cover most operational requirements completely. This is further enhanced by an inherent advantage of electric motors compared to internal combustion engines: the maximum torque is already available immediately on starting off, and does not need to be built up by an increasing engine speed. The underfloor lithium-ion batteries have a capacity of 14 kWh.

The particularly smooth-running and responsive six-cylinder petrol engine of the Sprinter Plug-In Hybrid develops an output of 190 kW (258 hp) from a displacement of 3.5 litres. Maximum torque is 340 Nm over a wide engine speed range of 2500 to 5000 rpm. As in the standard model, power transfer in the Sprinter Plug-In Hybrid is via a comfortable five-speed torque converter transmission.

The electric motor is not just able to get the Sprinter up to speed in particularly environmentally friendly fashion, however: it can also be used as a mobile generator and energy source for machinery - for example to power a pump or other electrical equipment used by tradesmen.