Apparatus for controlling negative pressure in internal combustion engine

摘要

An improved apparatus for controlling brake force is disclosed. An engine selectively performs a stratified charge combustion and a uniform charge combustion. A brake booster (71) is actuated by negative pressure an absolute value of which is greater than a predetermined magnitude. An electronic control unit (30) actuates the throttle valve (23) to apply the negative pressure to the brake booster when the magnitude relating to the pressure in the brake booster is smaller than the predetermined value. Engine condition is converted from the stratified charge combustion to the uniform charge combustion. A fuel injector directly injects the fuel into the cylinder to set the engine to perform the stratified charge combustion. A basic injection timing of the fuel injector is computed based on the operation state of the engine. The basic timing is advanced when the stratified charge combustion is performed and the negative pressure is applied to the brake booster.