An Experimental Study on the Effect of Electric Supercharger on the Performance of a Turbocharged Miller Cycle Gasoline Engine

To improve the brake thermal efficiency (BTE) and power response performance of gasoline engines, an experimental study is conducted on a 3-cylinder turbocharged Miller cycle gasoline engine with electrical supercharger (e-SC) to investigate the effects of e-SC on the fuel economy and power response performance of engine. Results show that e-SC can significantly enhance the capability of engine in introducing low-pressure exhaust gas recirculation (EGR) at low-speed high-load conditions. Under a condition of a rotational speed of 2 000 r/min and a BMET of 1.4 MPa, the maximum low-pressure ERG rate can increase from 15% to 25% and the engine achieves a BTE of 39.5%, due to the reductions of heat transfer loss, exhaust heat loss and unburned HC loss. At a rotational speed of 1 500 r/min, the switching-on of e-SC markedly increases the pressure rise rate of engine, with the transient response time shortened by 58%. In addition, e-SC gains a 12 kW engine power pay-off by consuming 3 kW of electric power, playing a role of amplifying engine power. © 2019, Society of Automotive Engineers of China. All right reserved.