On the Coefficient of Heat Transfer between Gases and Cylinder Walls of the Spark-Ignition Engine

Abstract

This investigation is concerned with the rates of heat transfer from the working gases to the combustion chamber walls of the internal combustion engines. The test engine used is a four stroke spark-ignition engine with a water cooled single cylinder, bore×stroke being 114.3×140 mm. On the basis of author's experimental results, it was ascertained that the coefficients of heat transfer in this engine agreed well with those which were calculated by Eichelberg's formula [numerical formula] in the expansion stroke, but did not so well in the compression stroke. Law of similarity has been rarely applied to the problems of periodic heat transfer in the internal combustion engines, but recently Karl Elser developed this research. In the present report, improving Elser's method, the relation between the dimensionless groups was found as follows, [numerical formula] where Δs : entropy change Cp : specific heat under constant pressure change θ : crank angle