Controller for four-stroke cycle internal-combustion engine

In a controller for an internal combustion engine having an odd number of cylinders and including a cylinder number counter and a rotational sensing apparatus comprising a disc directly connected to a crankshaft of said engine and a sensor opposing the disc, said disc having:

• a plurality of position identifying projections equal to a multiple N of the odd number of cylinders and arranged at equal angular spacing around the circumference of the disc, each of said projections having the same circumferential length;
• and
• a cylinder identifying projection positioned between two of the position identifying projections and having a circumferential length different from that of the position identifying projections;
• wherein said sensor generates a pulse signal whenever one of the position identifying projections or the cylinder identifying projection passes in front of the sensor;
• a microprocessor responsive to the pulses generated by the sensor, for:
• a. calculating the width t of each pulse;
• b. calculating the period T of each pulse, wherein the period is defined as the time from the rise of a given pulse to the time of the rise of an immediately succeeding pulse;
• c. calculating the pulse time ratio defined as t/T;
• d. calculating a difference quotient value .alpha. corresponding to the pulse time ratio of the current pulse and the pulse time ratio of an immediately preceding pulse;
• and
• e. when .alpha. is less than a predetermined reference value, incrementing the cylinder number counter, and otherwise resetting the cylinder number counter.

A controller for a four-stroke cycle internal combustion engine having an even number of cylinders, said controller comprising:

• position signal generating means mounted on a crankshaft of said internal-combustion engine for generating a position signal in synchronization with the revolution of said crankshaft, said position signal including a plurality of reference position pulses generated during each revolution of said crankshaft and a cylinder identifying pulse which is generated for a particular cylinder, the number of the reference position pulses generated during each crankshaft revolution being a multiple of N/2 (N is a natural number) of the number of cylinders;
• a reference position signal generating section for identifying the reference position of each cylinder from said position signal and for generating a reference position signal;
• a cylinder identifying section for identifying said each cylinder from said position signal and for generating a cylinder identifying signal;
• and
• a timing control section for generating a control signal for said each cylinder in accordance with said reference position signal and said cylinder identifying signal.

A controller for a four-stroke cycle internal-combustion engine having an odd number of cylinders, said controller comprising:

• position signal generating means mounted on a crankshaft of said internal-combustion engine for generating a position signal in synchronization with the revolution of said crankshaft, said position signal including a plurality of reference position pulses generated during each revolution of said crankshaft, and a cylinder identifying pulse which is generated for a particular cylinder, the number of the reference position pulses generated during each crankshaft revolution being a multiple of N (N is a natural number) of the odd number of cylinders;
• a reference position signal generating section for identifying a reference position for each cylinder from said position signal and generating a reference position signal;
• a cylinder identifying section for identifying said cylinders from said position signal and for generating a cylinder identifying signal;
• and
• a timing control section for generating a control signal for each cylinder in accordance with said reference position signal and said cylinder identifying signal.