Method for controlling limp-home of vehicular electronic throttle system

A system for controlling a limp-home function in a vehicular electronic throttle system, comprising an accelerator position sensor, a throttle valve driven by a throttle valve driver, a throttle position sensor, and a limp-home valve, each communicating with an electronic control unit, wherein:

• the electronic control unit is programmed to determine the presence of at least one of the following conditions based on said communication:
• whether the throttle valve has a problem of complete closure;
• whether a difference between a first output value set up as target by a throttle position sensor and a second output value measured by the throttle position sensor is greater than a first critical value and whether coolant temperature is larger than a reference value;
• whether an idle switch is turned on and whether engine revolution is less than a reference value;
• and
• whether a reference period of time has lapsed and whether a third output value of the throttle position sensor has dropped below a second critical value and whether coolant temperature is higher than a reference value while the idle switch is turned on;
• the electronic control unit turns on the limp-home valve if at least one of the conditions is met;
• the electronic control unit is programmed to determine whether a difference between a fourth output value set up as target by the throttle position sensor and a fifth output value measured by the throttle position sensor is less than a third critical value and whether a sixth output value established by the throttle position sensor is smaller than a fourth critical value while the idle switch is turned off;
• and
• to turn off the limp-home valve if said further programmed conditions are met.

A system for controlling a limp-home function in a vehicular electronic throttle system, comprising an accelerator position sensor, a throttle valve driven by a throttle valve driver, a throttle position sensor, and a limp-home valve, each communicating with an electronic control unit, wherein:

• the electronic control unit is programmed to determine the presence of at least one of the following conditions based on said communication:
• whether a difference between a first output value set up as target by a throttle position sensor and a second output value measured by the throttle position sensor is greater than a first critical value and whether coolant temperature is larger than a reference value;
• whether an idle switch is turned on and whether engine revolution is less than a reference value;
• and
• whether a reference period of time has lapsed and whether a third output value of the throttle position sensor has dropped below a second critical value and whether coolant temperature is higher than a reference value while the idle switch is turned on;
• and
• the electronic control unit turns on the limp-home valve if at least one of the conditions is met.