Smart "micro hybrid drive" car
Daimler's Smart introduced the smart fortwo mhd in October 2007 to vehicle showrooms, that added a new technology called "micro hybrid drive" (mhd) to the car. The key to this technology is that the smart car mhd shuts its engine off at idle, using what Daimler refers to as start/stop technology. Whenever the smart car mhd car brakes, and the speed drops to below 8 kph (5 mph), the engine will switch off and it will re-start whenever the brake pedal is released.
The efficiency benefit derived from micro hybrid drive is that at idle (like at a red light), the engine remains switched off. This reduces fuel consumption by as much as 19% in comparison to the conventional smart car if the majority of the vehicle's driving is done in the city. For the overall city/highway New European Driving Cycle, the smart car mhd benefits with an 8% reduction in fuel consumption, and the fuel economy goes from 4.7 to 4.3 L per 100 km (NEDC). CO2 emissions are also reduced from 112 to 103 grams per kilometre because of mhd.
The technology breakthrough in mhd is that the starter motor has a belt drive that also acts as generator when the smart car's 3 cylinder engine is running; it provides electricity for the car's power system and battery. This starter-drive starts the engine quietly and in fractions of a second.
The smart car fortwo mhd has a 3-cylinder inline gasoline (petrol) engine rated at 52 kW (71 hp) and 92 Nm of maximum torque The new technology belt-driven starter-generator produces a maximum torque of 42 Nm.