There’s standard ways to save fuel, and then there’s a switch to a mild hybrid system with 48 V electricals. That’s what the premium brands are doing with their flagship cars, most notably the Audi A8 and the Mercedes S-Class. The latter is also more interesting because it will switch to a straight-six engine from the current crop of V6 motors. The key here is an electrical motor attached to the crankshaft of the engine that can double up as both starter motor and alternator. It will also be able to offer assistance and and harvest energy under braking. Those figures stand at 19 bhp for the assistance and 20 bhp during regenerative braking. The immediate fuel efficiency gains from these are 10 per cent and 15 per cent respectively.
The electric motor cannot be disconnected from the crankshaft, so the next-gen S-Class will not be able to run on electric power alone, but what this system does is reduce complexity and weight (no need for both a starter motor and an alternator), offer extra torque when required, and regain electric energy under braking – all things that contribute to better fuel economy and fewer emissions. There’s also a four-cylinder petrol engine under development with a similar starter/alternator, but that will be a more conventional belt-driven one. What will make Indian-market customers happy is that this tech will be available on the diesels as well, so we can expect it across the range.
Source: Autocar UK
