| 摘要 |
An electronically controlled throttle device, eg in a motorcycle, comprises a throttle valve 21 which is opened or closed by a motor 23 via a gear 22 and is urged in the closing direction by a return spring 24. To diagnose a defect in the throttle device, a diagnosis unit 83a in the ECU 8 sets a target diagnosis opening degree of the throttle valve, drives the motor 23 and discriminates whether the sensed opening degree matches the diagnosis opening degree after a first predetermined time has passed. The diagnosis unit 83a then interrupts driving of the motor 23 to close the throttle valve fully by the force of the return spring 24 and discriminates whether the opening degree of the throttle valve matches a second diagnosis opening degree after a second predetermined time has passed, thereby enabling diagnosis of a defect in the return spring. The diagnosis unit calculates and sets the first and second predetermined times based on a state of the electronically controlled throttle device, eg ambient temperature, engine water and oil temperatures and (for the first predetermined time) the driving voltage of the motor 23.
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