Internal combustion engine technologies concerning thermal efficiency are discussed here. These technologies have tight relationship with thermodynamic efficiency, combustion, and heat transfer in the engine.

Especially heat release rate phasing/shaping and heat loss have to be focused to understand the thermal efficiency of the engine. This review article consists of following chapters: 1) Fundamental Concept of Thermal Efficiency, 2) Heat Release Rate and Effective Work, 3) Heat Transfer, 4) Thermal Efficiency Improvement, 5) Heat Transfer in IC Engine, 6) Flame and Heat Transfer, 7) Fuel and Engine Performance, 8) Synthesis Fuel and Engine Performance, and 9) SummariesFirst three chapters are concerning fundamental concepts for engine efficiency.

Especially in chapter 3, heat transfer physics that has to be understood by engine researches are explained. In Chapter 4, various improvement pathways of the efficiency are discussed.

Chapters 5 and 6 are concerning heat transfer problems that become the main improvement targets of advanced engine. In Chapters 7 and 8, advanced or new fuel problems are discussed.

In Chapter 9, new direction of engine development is pointed out. .