Development of an Instantaneous Heat Flux Measurement Technique for Very High In-Cylinder Pressure Diesel Engines

Abstract

Cooling loss reduction during combustion period could be an essential measure for further improvement in thermal efficiency of diesel engines. Direct measurement of local and instantaneous heat flux at various points of the in-cylinder surface will play an important role to reveal detailed mechanism of the cooling loss phenomena. However, there have been very limited number of studies with state-of-the-art engines. This paper reports the outline of a newly-developed thin-film-thermocouple type heat flux sensor, which can be fitted anywhere and is durable under very high in-cylinder pressure (up to 35MPa) aiming higher thermal efficiency, and achieved results by the sensor.