Abstract: Backward movement of a heavy motorcycle is assisted by a starter motor for cranking an engine of the motorcycle. A backward drive control system includes a pulse width modulation circuit for supplying operating current to the starter motor in a controlled manner and a device for estimating operating temperature of the starter motor based on the current supplied to the starter motor. When the estimated temperature reaches a predetermined maximum temperature, the operation of the starter motor is compulsorily stopped and prohibited for a certain period or until the starter motor is cooled down to a certain temperature level. Overheating of the starter motor is effectively prevented without using a temperature sensor for measuring the operating temperature.Moreover, chattering of the starter motor does not occur because its operation is prohibited for a certain period after the starter motor is once compulsorily stopped.

Abstract: A signal transmission system for transmitting, in particular, an ignition timing correction signal in an ignition timing control system for an internal combustion engine includes an ignitor for producing an ignition timing signal in response to an ignition signal from a distributor, and the ignition timing signal is further corrected by the ignition timing correction signal calculated in a computer based on engine operating conditions sensed by sensors. The computer includes a voltage-current converting circuit which converts the ignition timing correction signal in the form of a voltage signal into a current signal corresponding thereto and supplies the current signal to the ignitor through a signal line connecting between the computer and the ignitor. The ignitor includes a current-voltage converting circuit to convert the current signal from the computer into a voltage signal corresponding to the current signal which indicates the correction of the ignition timing.

Abstract: An ignition control system for controlling an ignition timing of an internal combustion engine when the CPU is failed or the engine is started, includes a charging and discharging circuit in which a predetermined crank angle range is converted into a voltage to be charged in which the charged voltage is discharged so as to form a charge and discharge voltage wave, a charge and discharge voltage wave comparison circuit for comparing the charge and discharge voltage wave with a battery voltage wave, and a back-up circuit for control the ignition timing in accordance with the signal from the charge and discharge voltage wave comparison circuit.

Abstract: A rotational position detecting apparatus for an internal combustion engine comprises a first and a second signal generator each thereof having a signal rotor rotating in synchronism with the rotation of the engine, a first and a second waveform reshaping circuit and a signal processing circuit. Engine rotational angle signals produced by the first signal generator and engine cylinder reference angular position signals and a specified cylinder angular position signal produced by the second signal generator are reshaped through the first and second waveform reshaping circuits, respectively, and both output signals from the first and second waveform reshaping circuits are supplied to the signal processing circuit. The signal processing circuit separates the reference signals and the cylinder discrimination signal from the output signals of the second waveform reshaping circuit and outputs the separated signals along with the angle signals produced by the first waveform reshaping circuit.

Abstract: A knocking detecting apparatus for an internal combustion engine with a knocking detector for detecting a factor of knocking in the engine and a circuit for generating a knocking discrimination level in response to the output signal of the knocking detector, for detecting knocking by comparing the output signal of the knocking detector and the knocking discrimination level. The knocking detecting apparatus comprises a circuit for clamping the output of the knocking discrimination level generator circuit such that the knocking discrimination level does not exceed a predetermined voltage.

Abstract: An ignition timing control apparatus for an internal combustion engine comprises a pick-up incorporated in a distributor for detecting a crank angle, a circuit for producing a basic ignition timing indicating signal on the basis of the output signal from the pick-up, a knocking detection circuit for generating a knocking detection signal, a circuit responding to the knocking detection signal and the basic ignition timing indicating signal to generate an actual ignition command signal delayed by a predetermined crank angle from the basic ignition timing, and the control apparatus further includes a circuit responding to these three signals to inhibit the operation of the knocking detection circuit during a period beginning at a time point which precedes to the operation of an inlet valve and an exhaust valve of a cylinder another than the cylinder in concern and terminating at a time point at which a predetermined time has elapsed since the ignition of the cylinder in concern.

Abstract: An ignition timing control system for an internal combustion engine includes a knocking reference level generator having an operational amplifier. The operational amplifier receives at its inverting terminal a filtered knock signal and produces a half-wave signal through a diode. The half-wave output signal of the diode is fed back to the inverting terminal of the operational amplifier through a feedback parallel circuit of a resistor and a capacitor.