Ignition control apparatus for internal combustion engine and control system for internal combustion engine

A control system comprising:

• an alternating current generator that generates an alternating current output voltage when a rotor of the alternating current generator is driven to rotate;
• a regulator that receives the alternating current output voltage generated by the alternating current generator and converts the alternating current output voltage into a direct current output voltage;
• a pulser provided at a predetermined rotational position where the rotation of the rotor can be identified;
• and
• an ignition control apparatus, the ignition control apparatus including:
• a rotational speed calculator that calculates a rotational speed of the rotor of the alternating current generator, the rotor of the alternating current generator being driven to rotate in synchronization with reciprocating motion of a piston of an internal combustion engine;
• an ignition timing determiner that determines an ignition timing of the internal combustion engine based on the rotational speed calculated by the rotational speed calculator;
• an ignition controller that supplies electric power to an ignition coil such that the internal combustion engine is ignited at the timing determined by the ignition timing determiner,
• wherein the rotational speed calculator calculates the rotational speed of the rotor based on a polarity signal provided by the regulator representing a polarity of an alternating current output voltage corresponding to at least one phase of the alternating current generator and a rotation signal provided by the pulser indicating that the rotor of the alternating current generator has passed through a predetermined rotational position when the internal combustion engine is started up;
• wherein the polarity signal includes a predetermined number of binary continuous pulses generated per rotation of the rotor based on a change in polarity of the alternating current output voltage, a period of which varies depending on the rotational speed of the rotor, and the rotation signal includes a set of positive and negative single pulses to be generated when the rotor passes through a predetermined rotational position;
• wherein the rotational speed calculator calculates a time period obtained by subtracting from a detection time of the single pulse first identifiable in the rotation signal a detection time of the continuous pulse identified in the polarity signal immediately before the single pulse has been identified, and calculates a rotational speed of the internal combustion engine using the time period and a predetermined rotation phase;
• and
• wherein the regulator includes a polarity signal generator that generates the polarity signal including a binary continuous pulse having values each corresponding to the polarity of the alternating current output voltage corresponding to at least one of phases of the alternating current generator.

An internal combustion engine, comprising:

• an alternating current generator that generates an alternating current output voltage when a rotor of the alternating current generator is driven to rotate;
• an ignition control apparatus, the ignition control apparatus including:
• a rotational speed calculator that calculates a rotational speed of the rotor of the alternating current generator, the rotor of the alternating current generator being driven to rotate in synchronization with reciprocating motion of a piston of the internal combustion engine;
• an ignition timing determiner that determines an ignition timing of the internal combustion engine based on the rotational speed calculated by the rotational speed calculator;
• and
• an ignition controller that supplies electric power to an ignition coil such that the internal combustion engine is ignited at the timing determined by the ignition timing determiner;
• wherein the rotational speed calculator calculates the rotational speed of the rotor based on a polarity signal representing a polarity of an alternating current output voltage corresponding to at least one phase of the alternating current generator and a rotation signal indicating that the rotor of the alternating current generator has passed through a predetermined rotational position when the internal combustion engine is started up;
• wherein the polarity signal includes a predetermined number of binary continuous pulses generated per rotation of the rotor based on a change in polarity of the alternating current output voltage, a period of which varies depending on the rotational speed of the rotor, and the rotation signal includes a set of positive and negative single pulses to be generated when the rotor passes through a predetermined rotational position;
• wherein the rotational speed calculator calculates a time period obtained by subtracting from a detection time of the single pulse first identifiable in the rotation signal a detection time of the continuous pulse identified in the polarity signal immediately before the single pulse has been identified, and calculates a rotational speed of the internal combustion engine using the time period and a predetermined rotation phase;
• and
• wherein the rotational speed calculator calculates the rotational speed of the rotor based on the rotation signal only after the internal combustion engine is started up.