Apparatus for controlling negative pressure in internal combustion engine

摘要

An apparatus for controlling brake force of a vehicle is disclosed. Each cylinders of a vehicle engine has a combustion chamber that receives fuel from a fuel injector and air from an air intake passage. The engine selectively performs a stratified charge combustion and a uniform charge combustion. The stratified charge combustion mode is selected to increase the amount of the air and the fuel supplied to the engine and improve a combusting state of the engine. The apparatus further includes a brake booster for increasing the brake force according to the negative pressure applied thereto. The brake booster is actuated by the negative pressure an amount of which is greater than a predetermined amount. Airflow in the air intake passage is restricted to generate the negative pressure. A fuel injector directly injects the fuel into the cylinder to set the engine to perform the stratified charge combustion. An electronic control unit (ECU) measures the an amount relating to the pressure applied to the brake booster. The ECU actuates the motor means to apply the negative pressure to the brake booster when the amount is smaller than the predetermined value and converts the driving condition of the engine from the stratified charge combustion to the uniform charge combustion.