Oliff & Berridge, P.L.C.
Air-fuel ratio control apparatus and method for internal combustion engine
 An air-fuel ratio control apparatus performs an intake air-increasing process based on a region of an air-fuel ratio feedback adjustment coefficient FAF in which the adjustment coefficient decreases the fuel concentration in an air-fuel mixture. The apparatus calculates a fuel injection valve open duration TAU by using a newly calculated air-fuel ratio feedback adjustment coefficient FAFx, instead of using an adjustment coefficient FAF. An air-fuel ratio-increasing feedback adjustment coefficient FVLV in the adjustment coefficient FAFx has a value that cancels an increase in the amount of intake air. Therefore, the fuel injection amount is increased only when the fuel concentration in the mixture is an intake air-increasing process. Hence, torque difference between fuel concentration-increasing and concentration-decreasing control becomes smaller. 
Toyota Jidosha Kabushiki Kaisha
F F
F02D F02D
inventional inventional
Harufumi Makoto Naoto
Muto Fujita Kushi