Abstract
The coefficients of heat transfer on combustion chamber walls of internal combustion engines differ according to individual locations, but no actual experimental results have been reported. This study determined the coefficients of local heat transfer at each location on the wall surfaces of a combustion chamber. The coefficients were obtained by the instantaneous temperature, the instantaneous heat flux at each location measured by highly accurate thin-film thermocouples developed by the authors, and the instantaneous gas temperature in the combustion chamber determined by the gas pressure in the combustion chamber, which is the only source of information on gas in the chamber. As a result. It was found that the engine speed, gas flow, ignition timing, distance from the plug, shape of the combustion chamber, and temperature significantly affect the local heat transfer coefficient. It was also found that Eichelbeg's formula or Woschni's formula, in which the gas flow is taken into account, yield substantial differences from the measured values at high engine speeds.
