Abstract: In a drive control apparatus for an electric actuator to be activated under control of a changeover switch, the drive control apparatus including a power transistor arranged to supply therethrough the power to the electric actuator from an electric power source in response to operation of the changeover switch, a presumptive temperature of the power transistor is previously memorized and renewed in consideration with an increment of temperature change caused by consumption of the power when the electric actuator has been activated. The presumptive temperature is further renewed in consideration with a decrement of temperature change caused by lapse of time after the electric actuator has been deactivated. The power supply to the electric actuator is permitted only when the presumptive temperature is lower than a predetermined value. When the presumptive temperature becomes higher than the predetermined value, the power supply to the electric actuator is prohibited.

Abstract: In an electric control apparatus for a clutch mechanism provided therein with a reversible electric motor which is activated under control of a changeover switch to engage the clutch mechanism in its forward rotation and to disengage the clutch mechanism in its reverse rotation, a first period of time is set when the changeover switch has been operated to engage the clutch mechanism, and a second period of time is set when the changeover switch has been operated to disengage the clutch mechanism. The first period of time represents a power supply time during which the electric motor is activated to cause full engagement of the clutch mechanism. The second period of time is defined to be longer than the first period of time and represents a power supply time during which the electric motor is activated to cause full disengagement of the clutch mechanism.

Abstract: In a part-time four-wheel drive vehicle, and electric control apparatus for a transfer device in drive connection to a front or rear differential is arranged to permit selection of the four-wheel drive mode at the transfer device during travel of the vehicle in the two-wheel drive mode only in a condition where travel speed of the vehicle and temperature of lubricating oil in the differential are in a predetermined allowable region. The allowable region is defined to permit engagement of a clutch mechanism in the transfer drive mode without causing any heavy load acting thereon.

Abstract: A cooling system for a radiator in an internal combustion engine is provided with a pair of fans connected to a first motor for a small electric current and a second motor for a large electric current, respectively. Relays are provided for operating the first and/or second motor sequentially in accordance with the degree of cooling requirement of the engine. A delay device is provided for delaying the operation of the relay(s) for attaining a stronger cooling requirement for a predetermined short period just after the engine is started. A generation of rush current in the relay contacts is prevented.

Abstract: In a diagnosis apparatus for an electronic control system adapted to vehicles and including a speed sensor for producing speed pulses responsive to the actual vehicle speed, a switch produces a diagnosis signal when actuated upon request for self-diagnosis in operation of the control system. A computer is responsive to the diagnosis signal to discriminate change of the level of each speed pulse during movement of the vehicle and to produce a first signal in dependence upon discrimination of change of the level of each speed pulse and a second signal in dependence upon discrimination of unchangeable state of the level of each speed pulse, and an indicator indicates an error in operation of the speed sensor in response to the second signal and normal operation of the speed sensor in response to the first signal.

Abstract: An engine automatic control system for vehicles is adapted to automatically stop the engine when the vehicle motion is arrested, to automatically start the engine in response to operation of a starting mechanism for effecting start of the vehicle, and to maintain the engine rotation after start of the vehicle in dependence upon change of the level of speed pulses from a speed sensor assembly. The control system is arranged to be ineffective in its function for automatic stop of the engine when the speed sensor assembly is inoperative to maintain the engine rotation under the operative condition of the control system.

Abstract: An engine is automatically stopped under predetermined conditions, thereafter, restarted under other predetermined conditions. The conditions of automatically stopping the engine includes at least a stopped state of a wiper which is driven by two-speed typed motor. Operating condition of the motor for driving the wiper is detected by a signal from either a low terminal or a high terminal of the motor.

Abstract: In a system wherein the operating conditions of various portions of a vehicle are detected and an engine is automatically stopped and started in accordance with the operating conditions thus detected, a fuel supply system is cut to prevent the run-on of the engine in addition to the cut-off of current passage to an ignition system as in the prior art. There controls are effected when both any one or more of predetermined operating conditions and any one or more of conditions of precluding the automatic stop are present.

Abstract: An automatic engine stop and start apparatus for automatically stopping and starting an engine is disclosed. When a car starts to move while the engine has been automatically stopped and the car is to be braked, and a car velocity exceeds a predetermined speed and a booster pressure of a brake falls below a predetermined level, the apparatus issues an alarm. To this end, the apparatus includes a car velocity sensor for detecting the car velocity, a slope sensor for detecting the necessity of the brake for the car, a negative pressure switch fordetecting the booster pressure of the brake and alarm means responsive to detection outputs of those sensors.