This study deals with the basic theoretical and experimental study on the transient convective heat transfer at the inside flat walls of internal combustion engines with gas-side static heat conduction model.
The model is such that, laminar boundary layers are shaped on the inside flat surface of piston and cylinder head, and, when piston moves or combustion takes place, every gas particles in the cylinder moves only vertically to the walls like accordion bags.
So, the convective heat transfer on the surface, can be replaced, by one dimensional heat conduction in the gas side, where, the propagation of combustion flame is replaced by moving heat generation zone.
When, heat generation takes place just on the bottom of boundary layer, the surface heat flux becomes maximum.
First, these theoretical models, and theoretical calculations of transient heat flux were checked by basic combustion experiments in two small closed vessels, and the theories have shown very good agreement to the experimental results.
Then, the theories were applied to a suppositional Diesel engine, and the calculated heat flux are compared to the values calculated by the Eicherbergs predictional equations. The both results have shown fairly good agreement to each other.
Then, a predictional equation of the mean heat flux of combustion chamber is developed through this theory, and some examples of calculation of the mean heat flux are shown. The results are generally in good agreement to the data of actual engines measured by many methods by many peoples.
Moreover, it is shown that, influences of various engine factors as engine speed, air-fuel ratio, etc, are easily analysed by using this theory, and their tendencies are in good agreements to the experiences.
Generally speaking, this study is hoped to have projected new light in the theoretical analysis of inside heat transfer of internal combustion engines, which were treated only experimentally until to-day.

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