Abstract: An electronic control apparatus for a vehicle includes first and second controllers between which the transmission of information is performed. A processor in the form of a microcomputer processes information transmitted from the first controller to the second controller and controls an actuator such as a brake actuator based on the information thus processed. An abnormality detecting circuit detects an interruption of signal transmission between the first and second controllers for a predetermined period of time, and it stops the control of the second controller on the actuator when it detects such an interruption. A transmission inhibitor is provided for inhibiting signal transmission from the second controller to the first controller when the abnormality detector detects an interruption.

Abstract: A cruise control apparatus for a vehicle which is highly reliable and safe in operation. The cruise control apparatus includes a cruise control setting switch for setting cruise control; a first switch operatively connected with the brake system in such a manner that it turns on and off the power supply to a throttle actuator, which acts to control the opening degree of a throttle valve, in response to brake release and application, respectively; and a second switch for cancelling the setting of cruise control. The cruise control apparatus determines whether there is a fault in either one of the first and second switches which continues for more than a predetermined time when the vehicle is travelling at a speed higher than a predetermined level, and it inhibits the cruise control setting switch from setting cruise control when there is such a fault.

Abstract: An improved fail-safe device for a motor vehicle speed governor of the type having a control system to switch a supply of power to an actuator ON and OFF for the control of the traveling speed of a motor vehicle to keep a constant speed. A latch is connected to power supply control circuit which controls the power supply to an actuator. The actuator actuates a throttle valve in an intake manifold of an engine for providing constant speed travel by turning the throttle valve ON and OFF in accordance with an output of the latch. The latch is set with a command signal and reset with a cancel signal or a reset signal. The resetting of the latch is executed if an absence of a watch dog signal is detected or a change of output generating status of the latch is detected under certain conditions. The state of the latch can be maintained if the conduction of a switching circuit for the actuator is detected regardless of a command signal to start up the constant speed traveling.

Abstract: A cruise control apparatus for a vehicle is disclosed which is highly reliable in operation and in which a target speed stored can be checked, and if there is any error in the stored target speed, cruise control is automatically inhibited or cancelled. In one embodiment, the vehicle speed sensed by a speed sensor is stored in a first area of a RAM as a first target speed and in a second area as a second target speed. A comparator compares the first target speed and the second target speed and outputs either one of the target speeds as a final target speed if the target speeds are equal to each other but outputs the lower one of the target speeds as the final target speed if there is disagreement therebetween. A cruise controller connected to receive the output of the comparator is adapted to be externally set into operation for controlling a throttle actuator in such a manner that a throttle valve is moved to a target degree of opening which corresponds to the final target speed.

Abstract: A constant speed control apparatus for a motor vehicle includes a setting section for setting a target vehicle speed, a first detection section for detecting a vehicle speed of a traveling vehicle, a shift-down signal output section for, when the detected vehicle speed is decreased from the target vehicle speed to fall outside a predetermined range in a constant speed travel state, outputting a signal to cause an automatic transmission to perform a shift-down operation, a second detection section for detecting that the detected vehicle speed is essentially recovered to the target vehicle speed after the shift-down signal is output, an estimation section for estimating a road surface inclination on the basis of an engine load and the detected vehicle speed, and a shift-up signal output section for, when the detection result by the second detection section and an estimation result of essentially not an uphill by the estimation section are established, outputting a shift-up signal to the automatic transmission.