Review of Improvement Methods of Internal Combustion Engine Efficiency

Internal combustion (IC) engines are the most preferred option for automotive powertrain. Two commonly used engine types are spark ignition and compression ignition engines. The stringent emission regulations motivate researchers to improve IC engine performance to increase efficiency and reduce emission levels. There are many factors that limit IC engines efficiency, for example heat losses, losses due to incomplete and imperfect combustion, heat losses during cooling, imperfect valve timing, etc. In this paper, a comprehensive review of the most common and compromising methods and technologies that can be used to optimize the IC engines efficiency is represented.