Patent ID: 6751544
Filing Date: 2004-06-15
Classification: F02D

Abstract:
A vehicle engine control device comprising a transmission in which at least a forward position, a reverse position, a neutral position, and a parking position can be selected by an operation of a selector lever, whereinthe control device includes a microprocessor, is constructed to receive electric supply from an on-vehicle battery through a power source switch, and includes engine rotational speed detection means for detecting a rotational speed of an engine, fuel injection means for supplying a fuel to the engine, a pair of accelerator position sensors for detecting a depression degree of an accelerator pedal, a pair of throttle position sensors for detecting a throttle valve opening degree of an intake throttle valve of the engine, a driving motor for carrying out an opening and closing control of the intake throttle valve in accordance with outputs of the pair of accelerator position sensors and the pair of throttle position sensors, a motor power source switching element for controlling electric supply to the driving motor, a default position return mechanism for returning the throttle valve opening degree to a default position for escape driving when the motor power source switching element breaks electric supply, and drive control means for the driving motor, and further includes abnormality detection means, an abnormality storage element, lower limit rotation threshold setting means, automatic shift escape running means, and selective shift escape running means, the abnormality detection means is means for always monitoring operations of a sensor system, a control system, and an actuator system relating to control of the intake throttle valve, detecting whether the intake throttle valve can be controlled, and generating a severe abnormality detection output when the intake throttle valve can not be controlled, when the abnormality detection means generates the severe abnormality detection output, the abnormality storage element stores this, breaks the motor power source switching element to stop electric supply to the driving motor, and is constructed such that its storage state is reset in at least one of closing and breaking of the power source switch, the lower limit rotation threshold setting means is means for setting a lower limit rotational speed at which the engine can continue to rotate, the automatic shift escape running means is means for controlling an engine rotational speed by the fuel injection control means in such a way that when electric supply to the driving motor is stopped, the engine rotational speed detected by the rotational speed detection means of the engine becomes a rotational speed less than a predetermined limiting rotational speed, and becomes a rotational speed greater than a minimum engine rotational speed set by the lower limit rotation threshold setting means, and the selective shift escape running means is means for controlling the engine rotational speed by the fuel injection control means in such a way that when there is an accelerator position sensor regarded as being normal after electric supply to the driving motor is stopped and the transmission is once selected to be put in the parking position, the engine rotational speed detected by the engine rotational speed detection means becomes a rotational speed less than a variable threshold rotational speed of a value substantially in proportion to the depression degree of the accelerator pedal set by variable threshold rotation setting means, and becomes a rotational speed greater than a minimum engine rotational speed set by the lower limit rotation threshold setting means.