All About China's New Record-Setting Diesel Engine

Diesel engines differ from gasoline engines in several key ways regarding design and operation.  Diesel engines waste less energy than their gas counterparts because they combust air using compression and don't require fuel to be ignited by a spark plug. A diesel engine produces more torque than gasoline engines, making them better for heavy-duty applications. Diesel engines are also built stronger than gas engines to handle the greater internal compression. 

All engines lose some of the fuel's potential energy in the form of dissipated heat. The ratio of a fuel's energy that an engine can turn into kinetic energy is called thermal efficiency, and is higher for diesel engines than their gasoline counterparts. Gas engines generally use about 20-35% of the potential energy of fuel burned and lose the rest as ambient heat or exhaust, while a typical diesel engine operates at a thermal efficiency of about 46%.

One company has been steadily raising the bar for thermal efficiency in diesel engines over the past few years. In September 2020, Weichai Power in Weifang, China produced an engine that set a new standard with a thermal efficiency of just over 50%. Weichai broke the 51% barrier in January 2022 and hit 52.28% that November, an accomplishment that meant a 12% reduction in emissions and the amount of fuel burned. Weichai wasn't done pushing the thermal efficiency envelope, though. At the World Congress on Internal Combustion Engines in Tianjin just a few days ago, Weichai demonstrated an engine with a remarkable thermal efficiency of 53.09%.