First and second law analysis of low heat rejection diesel engine

Abstract

In this study, a comparative first and second law analysis of a turbocharged diesel engine was performed. The main aim was to investigate the impact of thermal insulation on energy, and exergy balances of the engine. For this reason, both standard (STD) and low heat rejection (LHR) engines were thermodynamically analysed. Over the range of operating conditions investigated, the second law efficiencies of the STD and the LHR engines were found to vary from 30.70 to 44%, and 32 to 45.75% respectively. The second law efficiency of LHR diesel engine was 2.85% higher than that of STD diesel engine. The available exhaust energy of the LHR engine was also up to 12% higher. It is concluded that an additional exhaust recovery system, such as turbocompound and/or Rankine bottoming cycle should be used to improve a LHR engine performance.