Abstract: An evaporation system leak diagnostic apparatus that purges fuel vapor from a fuel tank into an intake system of an internal combustion engine via a canister, includes: a first closed system leak diagnostic unit that executes a leak diagnostic on a first closed system based on a tank internal pressure detected by a tank internal pressure detecting device while the first closed system is formed with a first closed system forming device; and a second closed system leak diagnostic unit that introduces pressure in the first closed system into a second closed system by forming a second closed system with a second closed system forming device, and executes a leak diagnostic on the second closed system based on the tank internal pressure detected by the tank internal pressure detecting device, after the leak diagnostic by the first closed system leak diagnostic unit.

Abstract: An evaporation system leak diagnostic apparatus that purges fuel vapor from a fuel tank into an intake system of an internal combustion engine via a canister, includes: a first closed system leak diagnostic unit that executes a leak diagnostic on a first closed system based on a tank internal pressure detected by a tank internal pressure detecting device while the first closed system is formed with a first closed system forming device; and a second closed system leak diagnostic unit that introduces pressure in the first closed system into a second closed system by forming a second closed system with a second closed system forming device, and executes a leak diagnostic on the second closed system based on the tank internal pressure detected by the tank internal pressure detecting device, after the leak diagnostic by the first closed system leak diagnostic unit.

Abstract: A throttle control apparatus comprises a throttle valve placed in an intake passage, a motor for driving the throttle valve, an electronic control unit (ECU) for controlling the motor, and a throttle sensor for detecting an actual opening degree of the throttle valve. The ECU determines that the throttle valve is frozen when the actual opening degree does not reach a target opening degree even after a driving time for driving the motor has exceeded a predetermined time, and then stores the actual opening degree at the time as an icing opening degree. The ECU supplies a driving duty to cause the motor to produce required driving torque for removal of icing and reverses the driving duty by open control, and controls the motor to bring an accumulated value of a deviation between the target opening degree and the icing opening degree to zero, thereby repeatedly swinging the throttle valve.

Abstract: A throttle control apparatus comprises a throttle valve placed in an intake passage, a motor for driving the throttle valve, an electronic control unit (ECU) for controlling the motor, and a throttle sensor for detecting an actual opening degree of the throttle valve. The ECU determines that the throttle valve is frozen when the actual opening degree does not reach a target opening degree even after a driving time for driving the motor has exceeded a predetermined time, and then stores the actual opening degree at the time as an icing opening degree. The ECU supplies a driving duty to cause the motor to produce required driving torque for removal of icing and reverses the driving duty by open control, and controls the motor to bring an accumulated value of a deviation between the target opening degree and the icing opening degree to zero, thereby repeatedly swinging the throttle valve.

Abstract: A low-pressure fuel filter is disposed in a fuel-return pipe from the fuel pressure regulator. In a portion of the fuel-return pipe between the fuel pressure regulator and a fuel element of the low-pressure fuel filter, a bypass device which includes, for example, a jet pump or an aperture may be provided so that fuel can flow back to the fuel tank, bypassing the fuel filter when the fuel filter is blocked.