Control system for engine

A control device for an engine provided in a vehicle including an accelerator pedal, the control device comprising:

• memory and a processor that calculate a basic fuel amount based on an accelerator opening degree detected by an accelerator sensor to control an injector so that a fuel amount to be supplied to a combustion chamber of the engine equals the basic fuel amount, the control device being configured to:
• estimate a catalyst temperature that is a temperature of a catalyst device;
• implement a fuel cut to stop fuel supply by the injector when the accelerator opening degree detected by the accelerator sensor is lower than a predetermined accelerator determination opening degree;
• in implementation of the fuel cut, implement an intake air amount increase control when the catalyst temperature is high to control an intake air amount adjustment device, which adjusts an intake air amount that is an amount of air drawn into the combustion chamber, so that the intake air amount is larger than when the catalyst temperature is low;
• when the fuel cut has ended and fuel supply by the injector is resumed, implement a fuel amount increase control to control the injector so that the fuel amount to be supplied to the combustion chamber is larger than the basic fuel amount;
• and
• prohibit the intake air amount increase control for a predetermined period after the control device ends the fuel amount increase control.

A control method for an engine provided in a vehicle including an accelerator pedal, an engine body including a combustion chamber, an exhaust passage and an intake passage each connected to the engine body, an injector that supplies fuel to the combustion chamber, an intake air amount adjustment device that adjusts an intake air amount that is an amount of air drawn into the combustion chamber, a catalyst device including a three-way catalyst, an accelerator sensor that detects an accelerator opening degree, the accelerator opening degree being an opening degree of the accelerator pedal, and a control device that calculates a basic fuel amount based on the accelerator opening degree detected by the accelerator sensor to control the injector so that a fuel amount to be supplied to the combustion chamber equals the basic fuel amount, the control method comprising:

• estimating a catalyst temperature that is a temperature of the catalyst device;
• implementing a fuel cut to stop fuel supply by the injector when the accelerator opening degree detected by the accelerator sensor is lower than a predetermined accelerator determination opening degree;
• in implementation of the fuel cut, implementing an intake air amount increase control when the catalyst temperature is high to control the intake air amount adjustment device so that the intake air amount is larger than when the catalyst temperature is low;
• when the fuel cut has ended and fuel supply by the injector is resumed, implementing a fuel amount increase control to control the injector so that the fuel amount to be supplied to the combustion chamber is larger than the basic fuel amount;
• and
• prohibiting the intake air amount increase control for a predetermined period after the control device ends the fuel amount increase control.