smart set to roll out a full complement of Alternative Drive Systems

All new components have been integrated in the existing smart cable harness and databus architecture. The electric motor is connected to the axle drive. The battery is housed under the driver's seat and is charged via the motor and by recuperation of the braking energy. This means that the hybrid drive is a fully independent system.

The smart fortwo micro hybrid drive (mhd)

From 15 October 2007 a particularly economical 52 kW variant of the smart fortwo with a start/stop function will roll off the production line in Hambach, France: the smart fortwo micro hybrid drive. From the end of the year it will be available as a coupé and a cabrio in all three lines – "pure", "pulse" and "passion". In addition, a limited special series that will offer an attractive price saving is planned to mark the market launch. The micro-hybrid variant will be available as a left-hand-drive ECE version in Germany along with other markets.

The smart fortwo micro hybrid drive uses idling phases to switch off the engine and temporarily completely avoid fuel consumption, exhaust gas and noise emissions. In combination with the automated manual transmission already fitted in the production vehicle, customers can comfortably use this function with maximum start/stop availability. Studies have shown that in everyday traffic vehicles come to a stop every 1.3 kilometres on average.

At the heart of the system is a special belt-driven starter generator that supplies the vehicle's electrical system with voltage and has a secondary function as a starter. It is able to smoothly start up the combustion engine in a fraction of a second as soon as the driver releases the brake pedal. This dispenses with the need for a conventional starter motor that works on the flywheel of the crank assembly.

In conjunction with slightly modified gear ratios, this strategy leads to a fuel saving of approximately 8 percent in the New European Driving Cycle (NEDC). The standard consumption is reduced by approximately 0.4 litres per 100 kilometres – from 4.7 litres to around 4.3 litres. Depending on the traffic situation (heavy slow traffic), this can lead to a fuel saving of approximately 13 percent.

There is also a corresponding reduction in CO2 emissions from 112 grams to approximately 103 grams per kilometre.

The system was developed by smart in cooperation with Valeo GmbH and the Gates Corporation. The mechanical assembly comprises the starter generator STARS 137 from Valeo. This generator delivers torque of 42 Newton metres or current of maximum 120 ampere at 14 volts – enough to guarantee a reliable engine start, even at a temperature of minus 25 degrees Celsius. To ensure a low-slip and durable connection of the crank assembly and the starter generator, both components were given wider belt pulleys, as was the water pump that is also driven. A six-rib poly-V-belt from Gates transmits the power.

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