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: An electric control apparatus for a transfer device in a part-time four-wheel drive vehicle is arranged to permit switchover of the transfer device from the two-wheel drive mode to the four-wheel drive mode when a difference in rotational speed between front and rear propeller shafts is smaller than a predetermined value and to prohibit switchover of the transfer device from the two-wheel drive mode to the four-wheel drive mode when the difference in rotational speed between the front and rear propeller shafts is larger than the predetermined value.

Abstract: In electronically controlling the amount of fuel passing through an electromagnetic valve into an intake system of an engine, the period during which fuel is injected is advanced at low engine temperatures as compared with the fuel injection period at high temperatures. As a result, a sufficiently long duration of time is created from fuel injection until burning, so that the fuel will be more completely atomized even at low engine temperatures, resulting in good fuel combustion.

Abstract: Disclosed is an apparatus for controlling secondary air for purifying exhaust gas discharged from an internal combustion engine. The apparatus comprises a pair of catalytic converters disposed in series within an exhaust system, a secondary air switching device communicated with two positions each of which is located respectively upstream of each of the catalytic converters, an actuating device for selectively communicating the secondary air switching device with each of the above-mentioned two positions, and a detecting device for detecting the temperature of the first catalytic converter located upstream of the second converter.If the detecting device detects a condition wherein the temperature of the first catalytic converter is lower than a predetermined level, secondary air is supplied to the position upstream of the first catalytic converter.