Fuel evaporation rate control system for a direct fuel injection type internal combustion engine

摘要

In a direct fuel injection type spark-ignition internal combustion engine in which a fuel is injected from a fuel injection nozzle into a cylinder onto the surface of the combustion chamber wall and then the fuel adhering to the wall is evaporated so as to generate a combustible mixture gas, the temperature of the combustion chamber wall is controlled so as not to rise excessively in a high engine load range by controlling the flow rate of an oil jet sprayed onto the back surface of the combustion chamber wall in accordance with engine operating parameters. The temperature of the combustion chamber wall in a low engine load range is maintained comparatively high by constructing the wall from a heat insulating structure. Through this control, the maximum combustion pressure at high engine loads can be held small and the cycle-by-cycle variation in rate of combustion at low engine loads can be kept small.