How Efficient are Engines: Thermodynamics and Combustion Efficiency

How efficient are engines? Combustion engines are stupefyingly inefficient. Most diesel engines do not even have a thermal efficiency of 50%. And, gasoline-powered vehicles are even more inefficient, considerably.

What is the current thermal efficiency or total efficiency for the current gasoline engines? - Quora

Maximum efficiencies for internal combustion engines: Thermodynamic limitations - Jerald A Caton, 2018

Nissan claims 50% thermal efficiency, from engine for e-Power hybrid system

Engine Efficiency and Thermodynamic Cycles

Explanation of the Brayton Cycle inside a Jet Engine

Heat Engine - Definition, Heat Engine Efficiency, Carnot Engine

Carnot efficiency - Energy Education

Thermo-chemistry of Fuel Air Mixtures

3.7 Brayton Cycle

Heat engine - Wikipedia

Heat Engines and Thermal Efficiency: H E A T, PDF, Internal Combustion Engine

Technical research on improving engine thermal efficiency - Hongyu Mu, Yinyan Wang, Chuanlei Yang, Hong Teng, Xingtian Zhao, Hongquan Lu, Dechun Wang, Shiyang Hao, Xiaolong Zhang, Yan Jin, 2022