Experimental study of heat transfer coefficient in a spark ignition engine (2nd Report, Examination of arrangement of heat transfer coefficient under motored conditions)

Many studies have been conducted on heat flux or the heat transfer coefficient in an engine in order to increase thermal efficiency and to solve thermal loading problems. The authors showed the relation between Re number and Nu number at near TDC under the motored condition and it was found to be subjected to the equation Nu = a+b·Reⁿ. To examine whether the formula could be adapted to compression and expansion strokes, the formula was compared to the experimental data during compression and expansion strokes. Also, the value of the authors' formula was compared to that of usual formula. The authors' formula is found to agree well with the experimental data, and it was confirmed to predict approximate the heat transfer coefficient in an engine.