Study on combustion irreversibility in turbocharged spark-ignition engines

The direct-injection (DI) and turbocharging strategies are recently adopted for spark-ignition (SI) engines in order to achieve better fuel economy and lower pollutant emissions. A comprehensive analysis is required in order to evaluate the effects of aforementioned strategies on in-cylinder combustion processes. The second law analysis is a proficient thermodynamic tool which is used for identifying irreversibilities and exploring the possibilities of thermal systems optimisation. The present work aims at carrying out an exergetic analysis of a downsized turbocharged DI SI engine. The engine is fuelled with E10 (gasoline with 10% of ethanol content) while experimental data is acquired for different engine operating conditions. The exergetic analysis identified the combustion irreversibilities. Moreover, a comparison between second law analyses of a previously analysed port fuel injection (PFI) naturally aspirated SI engine and turbocharged DI SI engine is also presented. The study concluded with the potential benefits and drawbacks of newly adopted strategies for SI engines.