While most consumers are now carefully looking at the fuel economy of their next car, legislators are still focusing their efforts on reducing vehicle emissions. While emission standards vary around the world, it is becoming increasingly difficult to meet the existing and future standards with incremental changes to conventional gasoline and diesel engines. Full hybrids, like the Toyota Prius and Ford Escape, offer fuel economy improvements, and as a direct result, produce lower CO2 emissions. But not every customer wants to buy one of the few hybrid models currently available. A mild hybrid system like the one proposed by Ricardo, an automotive consultant, allows downsizing of the engine by using a relatively low capacity battery in conjunction with an electric motor to boost torque when required. The system offers a no-compromise answer to improved fuel economy and reduced emissions, and is more cost effective. The system Ricardo developed with Valeo, known as Imogen, was demonstrated on an Opel Astra model originally propelled by a 2.0l diesel engine. The Imogen equipped prototype matches the power and torque of the original vehicle by using a 1.2 liter diesel engine combined with an electric starter/alternator mounted on the flywheel. Combined with electrification of the accessories and engine shut down, the car achieved a fuel economy of 3.98litres/100km in the NEDC cycle, a 28% improvement of the baseline vehicle and tailpipe emissions reduced to half of the Euro 4 standards.
[Source: Engineer Live!]