Study of the electric-booster and turbo-generator system and its influence on a 1.5 L gasoline engine

Abstract

To effectively recovery the energy in exhausts and improve the transient performance of internal combustion engine. In this paper, a new electric turbo-compounding layout called electric-booster and turbo-generator system (EBTG) was established and studied in a 1.5 L gasoline engine. In the EBTG system, the turbo and compressor operate independently. Its impact on a gasoline engine was analyzed from the perspective of fuel economy, power output, availability distribution and transient performance. Results show that the proposed EBTG system is effective to improve the thermal efficiency of engine at high-speed and wide-open throttle conditions. Simultaneously, it is also valuable to solve the turbo-lag of engine. By applying EBTG system, the maximum reduction of specific fuel consumption was 2.6%. Exergy analysis showed that the EBTG system can reduce the irreversibility in turbine and recovery more exergy from exhausts. There was a 0.8 percentage point exergy efficiency increment at 4400 rpm and full-load operation. The step response time of boost pressure in EBTG engine decreased to about half of it in baseline at 2000 rpm and full-load condition.