Thermal Effect upon Air Capacity of the Four-Stroke Engine : 1st Report, Thermodynamical Analysis Method

The temperature changes of the mixture gas in the induction process are given using the following notation : ΔT1 : Vaporization of fuel, ΔT2 : Ram effect, ΔT3 : Preheating for intake mixture, ΔT4 : Heat transfer from high temperature parts, ΔT5 : Mixing with residual gas. The change ΔT5 has almost no effect on air capacity, but ΔT2, ΔT3 and ΔT4 change with engine types, operation and atmospheric conditions. Report No. 1 has expressed the sum of ΔT2, ΔT3, and ΔT4 (called ΔT2, 3, 4) as a function of the directly measurable intake mixture gas weight and the cylinder pressures. The suction end temperature T1 is a function of ΔT2, 3, 4 and pressures needed for thermodynamical analysis. It has become possible to determine each of the changes ΔT1 to ΔT5 analytically. Finally the relationship between the air capacity and various temperature rises of the mixture gas is expressed theoretically.