Oliff & Berridge, PLC
Apparatus and method for controlling combustion in stratified charge combustion engine
 An apparatus and method for controlling combustion of an engine. The engine has a throttle valve located in an intake duct connected to combustion chambers, and a brake booster actuated by vacuum supplied by the intake duct. During stratified charge combustion, if vacuum supplied to the brake booster is insufficient, an ECU decreases the opening of the throttle valve thereby increasing the vacuum. The ECU switches the combustion mode to stratified charge combustion if a target injection amount, which corresponds to load applied to the engine, is equal to or smaller than a predetermined value. When the target injection amount is greater than the value, the ECU switches the combustion mode to homogeneous charge combustion. During stratified charge combustion, the ECU sets the determination value to a smaller value when an operation for producing vacuum is performed than when the operation is not performed. This procedure improves fuel economy. 
Toyota Jidosha Kabushiki Kaisha
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Jun Hiroyuki
Takahashi Mizuno