Electronic control device for motor vehicle use

Claim 1

An electronic control device for motor vehicle comprising: a plurality of sensors for detecting the operation conditions of a motor vehicle; control means for calculating control data for said motor vehicle in view of output signals of said sensors, and for outputting control signals according to said control data; solenoid valve controlled in view of said control signals outputted by said control means; and failure detecting means for monitoring the state of said solenoid valve every predetermined period of time to determine that said solenoid valve and a drive circuit thereof are out of order, when said solenoid valve is held in the same state for a predetermined period of time.

Claim 6

A method of detecting failure of an electronic control device for motor vehicle in which said device comprises a plurality of sensors for detecting the operation conditions of a motor vehicle; control means for calculating control data for said motor vehicle in view of output signals of said sensors, and for outputting control signals according to said control data; solenoid valve controlled in view of said control signals outputted by said control means; and failure detecting means for monitoring the state of said solenoid valve every predetermined period of time to determine that said solenoid valve and a drive circuit thereof are out of order, when said solenoid valve is held in the same state for a predetermined period of time, said method comprising the steps of: reading an output signal of a port provided with said failure detecting means; determining whether o not said output signal applied to said solenoid valve is changed; if said output level of said port is different from the preceding one; (a) determining that the control of solenoid valve is normal; (b) setting a failure determining time "T" in a failure determining timer provided with said failure detecting means; if said output level of said port is the same as the previous one; (a) decreasing the value of a timer "T"; (b) determining whether or not the valve of said timer "T" is zero; if the value of said timer T is not zero; (a) determining that the control of said solenoid valve is normal: if the value of said timer is zero: (a) determining that the state of said solenoid valve is held unchanged for a period of time than a duty period; and (b) determining that one of said solenoid valve and its drive circuit is out of order.

Claim 7

A method of detecting failure of an electronic control device for motor vehicle in which said device comprises a plurality of sensors for detecting the operation conditions of a motor vehicle; control means for calculating control data for said motor vehicle in view of output signals of said sensors, and for outputting control signals according to said control data; solenoid valve controlled in view of said control signals outputted by said control means; and failure detecting means for monitoring the state of said solenoid valve every predetermined period of time to determine that said solenoid valve and a drive circuit thereof are out of order, when said solenoid valve is held in the same state for a predetermined period of time, said method comprising the steps of: reading an output signal of a port provided with said failure detecting means; determining whether o not said output signal applied to said solenoid valve is changed; if said output level of said port is different from the preceding one; (a) determining that the control of solenoid valve is normal; (b) setting a failure determining time "T" in a failure determining timer provided with said failure detecting means; if said output level of said port is the same as the previous one; (a) decreasing the value of a timer "T"; (b) determining whether or not the valve of said timer "T" is zero; if the value of said timer T is not zero; (a) determining that the control of said solenoid valve is normal: if the value of said timer is zero: (a) determining that the state of said solenoid valve is held unchanged for a period of time than a duty period; and (b) determining that one of said solenoid valve and its drive circuit is out of order.