A throttle control method for an internal combustion engine to be executed by an electronic control unit included in a throttle control device for an internal combustion engine,
- the throttle control device comprising:
- a supercharger comprising a throttle valve provided in an intake path for the internal combustion engine, a turbine provided in an exhaust path, and a compressor provided upstream of the throttle valve so as to rotate integrally with the turbine;
- a throttle motor for driving the throttle valve to change a flow-path sectional area of the bypass passage;
- a wastegate valve provided in a bypass passage which bypasses the turbine;
- a wastegate valve actuator for driving the wastegate valve to change a flow-path sectional area of the bypass passage;
- a throttle-valve upstream pressure detecting section for detecting, as a throttle-valve upstream pressure, a pressure in the intake path between a portion located downstream of the supercharger and a portion at which the throttle valve is provided;
- an accelerator position sensor for detecting an accelerator opening amount;
- and
- the electronic control unit for controlling the wastegate valve and the throttle valve in accordance with a current operating state,
- the throttle control method comprising:
- determining, by the electronic control unit, whether the current operating state is a high-load operation by comparing the throttle-valve upstream pressure detected by the throttle-valve upstream pressure detecting section with a predefined threshold pressure and by comparing the accelerator opening amount detected by the accelerator position sensor with a predefined first threshold opening amount;
- determining, by the electronic control unit, when the throttle-valve upstream pressure detected by the throttle-valve upstream pressure detecting section is equal to or larger than the predefined threshold pressure and the accelerator opening amount detected by the accelerator position sensor is equal to or larger than the predefined first threshold opening amount, that the current operating state is the high-load operation;
- determining, by the electronic control unit, in response to the determination that the current operating state is the high-load operation, whether the throttle valve is closed during the high-load operation and whether the current operating state enters a deceleration operation region by comparing the accelerator opening amount detected by the accelerator position senor with a predefined second threshold opening amount this is a value smaller than the first threshold opening amount;
- determining, by the electronic control unit, when the accelerator opening amount detected by the accelerator position sensor is equal to or smaller than the predefined second threshold opening amount, that the current operating state enters the deceleration operation region during the high-load operation;
- controlling, by the electronic control unit, in response to the determination that the current operating state enters the deceleration operation region during the high-load operation, the wastegate valve actuator to fully open the wastegate valve and controlling, by the electronic control unit, the throttle motor to fully open the throttle valve;
- comparing, by the electronic control unit, in response to the wastegate valve actuator fully opening the wastegate valve and the throttle motor fully opening the throttle valve, the throttle-valve upstream pressure detected by the throttle-valve upstream pressure detecting section with the predefined threshold pressure;
- and
- controlling, by the electronic control unit, when the throttle-valve upstream pressure detected by the throttle-valve upstream pressure detecting section becomes lower than the predefined threshold pressure, the throttle motor to fully close the throttle valve.