Improvements of vehicle fuel economy using mechanical regenerative braking

The paper presents a mixed theoretical and experimental evaluation of the improvements in fuel economy that follow the introduction of a mechanical Kinetic Energy Recovery System (KERS) on a full size passenger car. This system, made up of a high speed storage flywheel and a Constant Variable Transmission (CVT), has a full regenerative cycle overall efficiency about twice the efficiency of battery-based hybrids. With reference to the baseline configuration having a 4L gasoline engine, adoption of a KERS may reduce the fuel consumption covering the NEDC by 25% without downsizing, and by 33% downsizing the engine to 3.3L.