Abstract: The apparatus comprises two accelerator position sensors and two throttle position sensors, and when one out of said two accelerator position sensors or said two throttle position sensors fails to operate, a limitation is added to the increase in accelerator position for the output characteristics of the accelerator position sensor. Thereby, the vehicle is enabled to travel at a minimum speed necessary without excessively increasing the engine output. When one of the two throttle position sensors fails to operate, the fuel injection quantity may be set based on the detection value of the accelerator position, which enables the vehicle to be driven by approximately the desired speed without excessively increasing the engine output.

Abstract: The apparatus comprises two accelerator position sensors and two throttle position sensors, and when one out of said two accelerator position sensors or said two throttle position sensors fails to operate, a limitation is added to the increase in accelerator position for the output characteristics of the accelerator position sensor. Thereby, the vehicle is enabled to travel at a minimum speed necessary without excessively increasing the engine output. When one of the two throttle position sensors fails to operate, the fuel injection quantity may be set based on the detection value of the accelerator position, which enables the vehicle to be driven by approximately the desired speed without excessively increasing the engine output.

Abstract: In a method and apparatus for fail-safe controlling an electronically-controlled throttle-type internal combustion engine, provision is made of two accelerator position sensors and two throttle position sensors. When either one of the two accelerator position sensors or either one of the two throttle position sensors fails to operate, a low-speed fail-safe operation of a minimum compensation, that is, an operation for maintaining a minimum output required for limp-home control operation of the engine, is executed and, then, a first fail-safe control operation is executed for controlling the position of the throttle valve using a value detected by the remaining sensor. Therefore, the throttle valve is not unintentionally opened, and the operation can be smoothly shifted to the first fail-safe control operation.

Abstract: In a computer-controlled internal combustion engine with an electronically-controlled throttle system, a duplex throttle-position sensor system, a duplex accelerator-position sensor system, and other engine/vehicle sensors/switches, a sensor-failure detection and fail-safe system is configured to be electronically connected to the two throttle position sensors, the two accelerator position sensors and a vehicle-deceleration sensor for responding to a failure in at least one of the two throttle position sensors and the two accelerator position sensors for failsafe purposes. The sensor-failure detection and fail-safe system comprises a duplex failsafe system for the throttle-position sensor system and a duplex failsafe system for the accelerator-position sensor system, to provide superior fail-safe functions despite the presence of a throttle-position sensor failure and/or an accelerator-position sensor failure.