Valve feedback control having redundant valve opening sensors

A throttle control apparatus for internal combustion engines for controlling a throttle valve by a direct current motor in accordance with the depression of an accelerator pedal, the apparatus comprising:

• two throttle angle sensors operatively coupled with the throttle valve to detect its degree of opening;
• abnormality determination means for determining that one of the two sensors is abnormal when a difference between outputs of the two sensors is greater than a predetermined value;
• and
• abnormal sensor determination means responsive to an abnormality determination by said abnormality determination means for determining which of the two sensors is abnormal when a valve control parameter generated in response to an output of one of said sensors exceeds a threshold for a predetermined period of time.

A valve control system comprising:

• a plurality of valve angle sensors, each sensor disposed to detect the degree of valve opening;
• and
• a feedback control circuit connected to receive inputs from each of said sensors and to provide a control output connected to drive a valve-controlling motor;
• said control circuit including means to detect which, if any, of said sensors is abnormal by monitoring said control output.

A valve control method comprising:

• detecting the degree of valve opening using a plurality of valve angle sensors, each sensor disposed to detect the degree of valve opening;
• processing outputs from one of said sensors to provide a control output connected to drive a valve-controlling motor;
• monitoring the outputs of all sensors to determine when a sensor abnormality has occurred;
• and
• detecting which of said sensors is abnormal by monitoring said control output.