Investigations of energy, exergy distribution characteristics of overall working conditions and effect of key boundary parameters on residual energy availability in an automotive turbocharged diesel engine

Abstract

In this paper, an automotive turbocharged diesel engine was employed to explore energy, exergy distribution characteristics at overall working conditions and key boundary parameters influence on residual energy availability based on test, simulation and theoretical calculation means. The results show that first, low efficiency regions coincide basically with low load regions, while higher efficiency regions are mostly concentrated in higher load regions at medium speed. Secondly, exhaust energy power and exhaust exergy power are positively correlated with load and speed, speed has a greater impact on exhaust energy percentage than load, but a less influence on exhaust exergy percentage. Third, heat transfer energy power and exergy power are positively correlated with load and speed in medium-low output power working conditions, but remain basically unchanged in high output power working conditions. Fourth, high exergy destruction regions are all located in low load regions, exergy destruction degree increases gradually from inside to outside in combustion chamber, EDR (exergy destruction rate) peak value is acquired around theoretical ER (fuel-air equivalent ratio), EDR increases with ER raising in dilute mixing zone. Finally, REAC (residual energy availability coefficient) of exhaust and heat transfer are almost positively correlated with load, measures to decrease REAC are basically parallel with enhancing efficiency by key boundary parameters adjustment.