Abstract
The amount of air into IC engine’s cylinders is affected by the heat transfer at the intake system, which is changed by the development of thermal boundary layer, the opening and closing of intake valve, and so forth. Our previous study developed the empirical equation for the intake manifold model assuming as the cycle-averaged quasi-steady state heat transfer. On the other hand, the present study also improved the newly empirical equation with the quasi-steady state heat transfer for the intake manifold of the actual IC engine. Consequently, the Nusselt number used in the newly empirical equation was expressed by using the Reynolds number, the Gratez number and the Strouhal number, which represents the effects of the intake air gas flow rate, the development of thermal boundary layer and the engine speed, respectively. In addition, the outlet air temperature at the intake port was estimated with the accuracy of maximum error of 5.6%, which was improved in comparison with the results obtained from the Colburn equation.
