Signal generator for multi-cylinder internal combustion engine and rotation information detector using signal generator

A signal generator for a multi-cylinder internal combustion engine, used for detecting rotation information of the multi-cylinder internal combustion engine having a first cylinder and a second cylinder, comprising:

• a rotor in the form of an inductor having a first series of two reluctors that are placed at a substantially 180° interval in a rotational direction of a crankshaft of said internal combustion engine correspondingly to two cylinders of said internal combustion engine and are rotated together with said crankshaft around a central axis of said crankshaft, and a second series of at least one reluctor that is provided in a position shifted axially along said crankshaft relative to said first series of reluctors and is rotated together with said first series of reluctors;
• a first sensor that detects a leading edge and a trailing edge in each rotational direction of the first series of two reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• and
• a second sensor that detects a leading edge and a trailing edge in a rotational direction of the second series of reluctor of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities,
• wherein polar arc angles of said first and said second series of reluctors, a positional relationship between said first and said second sensors, and a positional relationship between said first and said second series of reluctors are set so that said second sensor detects the leading edge or the trailing edge of the second series of one reluctor to generate either of the leading edge detection pulse or the trailing edge detection pulse while said first sensor sequentially detects the leading edge and the trailing edge of one of the first series of two reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, and so that said second sensor generates no pulse while said first sensor sequentially detects the leading edge and the trailing edge of the other of the first series of two reluctors to generate the leading edge detection pulse and the trailing edge detection pulse.

A signal generator for a multi-cylinder internal combustion engine, used for detecting rotation information including information on a rotational direction of the multi-cylinder internal combustion engine having first to third cylinders, comprising:

• a rotor in the form of an inductor having a first series of three reluctors that are placed at substantially 120° intervals in a rotational direction of a crankshaft of said internal combustion engine correspondingly to three cylinders of said internal combustion engine and are rotated together with said crankshaft around a central axis of said crankshaft, and a second series of at least one reluctor that is provided in a position shifted axially along said crankshaft relative to said first series of reluctors and is rotated together with said first series of reluctors;
• a first sensor that detects a leading edge and a trailing edge in a rotational direction of each of the first series of three reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• and
• a second sensor that detects a leading edge and a trailing edge in a rotational direction of each of the second series of two reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities,
• wherein polar arc angles of said first and said second series of reluctors, a positional relationship between said first and said second sensors, and a positional relationship between said first and said second series of reluctors are set so that said second sensor detects the leading edge or the trailing edge of the second series of one reluctor to generate the leading edge detection pulse or the trailing edge detection pulse while said first sensor sequentially detects the leading edge and the trailing edge of one of the first series of three reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, so that said second sensor detects the leading edge and the trailing edge of the second series of another reluctor to generate the leading edge detection pulse or the trailing edge detection pulse while said first sensor sequentially detects the leading edge and the trailing edge of another of the first series of three reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, and so that said second sensor detects no pulse while said first sensor sequentially detects the leading edge and the trailing edge of further one of said first series of three reluctors to generate the leading edge detection pulse and the trailing edge detection pulse.

A rotation information detector for detecting rotation information of a multi-cylinder internal combustion engine having two or more cylinders, comprising:

• a rotor in the form of an inductor having a first series of reluctors as many as cylinders of said internal combustion engine, that are provided correspondingly to each cylinder of said internal combustion engine and are rotated together with a crankshaft around a central axis of said crankshaft of said internal combustion engine, and a second series of at least one reluctor that is provided in a position shifted axially along said crankshaft relative to said first series of reluctors and is rotated together with said first series of reluctors;
• a first sensor that detects a leading edge and a trailing edge in a rotational direction of said first series of reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• a second sensor that detects a leading edge and a trailing edge in a rotational direction of the second series of reluctor of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• rotational direction discrimination means for discriminating the rotational direction of said internal combustion engine based on a phase relationship between the leading edge detection pulse and the trailing edge detection pulse generated by said first sensor and the leading edge detection pulse and the trailing edge detection pulse generated by said second sensor;
• and
• cylinder discrimination means for discriminating that, when said second sensor generates one pulse while said first sensor sequentially generates the leading edge detection pulse and the trailing edge detection pulse, the leading edge detection pulse and the trailing edge detection pulse sequentially generated by said first sensor correspond to a particular cylinder of said internal combustion engine,
• wherein polar arc angles of said first and said second series of reluctors, a positional relationship between said first and said second sensors, and a positional relationship between said first and said second series of reluctors are set so that said second sensor detects the leading edge or the trailing edge of the second series of one reluctor to generate one pulse while said first sensor sequentially detects at least one leading edge and at least one trailing edge of said first series of reluctors to generate the leading edge detection pulse and the trailing edge detection pulse.

A rotation information detector for detecting rotation information including information on a rotational direction of a multi-cylinder internal combustion engine having a first cylinder and a second cylinder, comprising:

• a rotor in the form of an inductor having a first series of two reluctors that are placed at a substantially 180° interval in a rotational direction of a crankshaft of said internal combustion engine correspondingly to two cylinders of said internal combustion engine and are rotated together with said crankshaft around a central axis of said crankshaft, and a second series of at least one reluctor that is provided in a position shifted axially along said crankshaft relative to said first series of reluctors and is rotated together with said first series of reluctors;
• a first sensor that detects a leading edge and a trailing edge in each rotational direction of the first series of two reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• a second sensor that detects a leading edge and a trailing edge in a rotational direction of the second series of reluctor of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• rotational direction discrimination means for discriminating the rotational direction of said internal combustion engine based on a phase relationship between the leading edge detection pulse and the trailing edge detection pulse generated by said first sensor and the leading edge detection pulse and the trailing edge detection pulse generated by said second sensor;
• and
• cylinder discrimination means for discriminating that, when said second sensor generates the leading edge detection pulse or the trailing edge detection pulse while the first sensor of said signal generator sequentially detects the leading edge and the trailing edge of one of said first series of two reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, the leading edge detection pulse and the trailing edge detection pulse generated when said first sensor detects the leading edge and the trailing edge of one of said first series of reluctors correspond to one cylinder of said internal combustion engine, and for discriminating that, when the second sensor generates no pulse while said first sensor sequentially detects the leading edge and the trailing edge of the other of said first series of reluctors to sequentially generate the leading edge detection pulse and the trailing edge detection pulse, the leading edge detection pulse and the trailing edge detection pulse generated when the first sensor detects the leading edge and the trailing edge of the other of the first series of reluctors correspond to the other cylinder of the internal combustion engine,
• wherein polar arc angles of said first and said second series of reluctors, a positional relationship between said first and said second sensors, and a positional relationship between said first and said second series of reluctors are set so that said second sensor detects the leading edge or the trailing edge of the second series of one reluctor to generate either of the leading edge detection pulse or the trailing edge detection pulse while said first sensor sequentially detects the leading edge and the trailing edge of one of the first series of two reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, and so that said second sensor generates no pulse while said first sensor sequentially detects the leading edge and the trailing edge of the other of the first series of two reluctors to generate the leading edge detection pulse and the trailing edge detection pulse.

A rotation information detector for detecting rotation information including information on a rotational direction of a multi-cylinder internal combustion engine having first to third cylinders, comprising:

• a rotor in the form of an inductor having a first series of three reluctors that are placed at substantially 120° intervals in a rotational direction of a crankshaft of said internal combustion engine correspondingly to three cylinders of said internal combustion engine and are rotated together with said crankshaft around a central axis of said crankshaft, and a second series of at least one reluctor that is provided in a position shifted axially along said crankshaft relative to said first series of reluctors and is rotated together with said first series of reluctors;
• a first sensor that detects a leading edge and a trailing edge in a rotational direction of each of the first series of three reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• a second sensor that detects a leading edge and a trailing edge in a rotational direction of each of the second series of two reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• rotational direction discrimination means for discriminating the rotational direction of said internal combustion engine based on a phase relationship between the leading edge detection pulse and the trailing edge detection pulse generated by said first sensor and the leading edge detection pulse and the trailing edge detection pulse generated by said second sensor;
• and
• cylinder discrimination means for discriminating that, when said second sensor generates the leading edge detection pulse or the trailing edge detection pulse while said first sensor of said signal generator sequentially detects the leading edge and the trailing edge of one of said first series of three reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, the leading edge detection pulse and the trailing edge detection pulse generated when said first sensor detects the leading edge and the trailing edge of one of said first series of three reluctors correspond to one cylinder of the internal combustion engine, for discriminating that, when said second sensor generates the leading edge detection pulse and the trailing edge detection pulse while said first sensor sequentially detects the leading edge and the trailing edge of another of the first series of three reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, the leading edge detection pulse and the trailing edge detection pulse generated when said first sensor detects the leading edge and the trailing edge of another of said first series of three reluctors correspond to another cylinder of said internal combustion engine, and for discriminating that, when said second sensor generates no pulse while said first sensor sequentially detects the leading edge and the trailing edge of further one of said first series of reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, the leading edge detection pulse and the trailing edge detection pulse generated when said first sensor detects the leading edge and the trailing edge of further one of said first series of three reluctors correspond to a further cylinder of said internal combustion engine,
• wherein polar arc angles of said first and said second series of reluctors, a positional relationship between said first and said second sensors, and a positional relationship between said first and said second series of reluctors are set so that said second sensor detects the leading edge or the trailing edge of the second series of one reluctor to generate the leading edge detection pulse or the trailing edge detection pulse while said first sensor sequentially detects the leading edge and the trailing edge of one of the first series of three reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, so that said second sensor detects the leading edge and the trailing edge of the second series of another reluctor to generate the leading edge detection pulse or the trailing edge detection pulse while said first sensor sequentially detects the leading edge and the trailing edge of another of the first series of three reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, and so that said second sensor detects no pulse while said first sensor sequentially detects the leading edge and the trailing edge of further one of said first series of three reluctors to generate the leading edge detection pulse and the trailing edge detection pulse.

A rotation information detector for detecting rotation information of a multi-cylinder internal combustion engine having two or more cylinders, comprising:

• a rotor in the form of an inductor having a first series of reluctors as many as cylinders of said internal combustion engine, that are provided correspondingly to each cylinder of said internal combustion engine and are rotated together with a crankshaft around a central axis of said crankshaft of said internal combustion engine, and a second series of at least one reluctor that is provided in a position shifted axially along said crankshaft relative to said first series of reluctors and is rotated together with said first series of reluctors;
• a first sensor that detects a leading edge and a trailing edge in a rotational direction of said first series of reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• a second sensor that detects a leading edge and a trailing edge in a rotational direction of the second series of reluctor of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• rotational direction discrimination means for discriminating the rotational direction of said internal combustion engine based on a phase relationship between a pulse with one polarity generated by said first sensor and the leading edge detection pulse and the trailing edge detection pulse generated by said second sensor;
• and
• cylinder discrimination means for discriminating which cylinder of the internal combustion engine the pulse generated by said first sensor corresponds to, from a polarity or the number of pulses generated by said second sensor between when said first sensor generates said pulse with one polarity and when said first sensor generates a pulse with the same polarity again,
• wherein polar arc angles of said first and said second series of reluctors, a positional relationship between said first and said second sensors, and a positional relationship between said first and said second series of reluctors are set so that said second sensor detects the leading edge or the trailing edge of the second series of one reluctor to generate one pulse while said first sensor sequentially detects at least one leading edge and at least one trailing edge of said first series of reluctors to generate the leading edge detection pulse and the trailing edge detection pulse.

A rotation information detector for detecting rotation information of a multi-cylinder internal combustion engine having two or more cylinders, comprising:

• a rotor in the form of an inductor having a first series of reluctors as many as cylinders of said internal combustion engine, that are provided correspondingly to each cylinder of said internal combustion engine and are rotated together with a crankshaft around a central axis of said crankshaft of said internal combustion engine, and a second series of at least one reluctor that is provided in a position shifted axially along said crankshaft relative to said first series of reluctors and is rotated together with said first series of reluctors;
• a first sensor that detects a leading edge and a trailing edge in a rotational direction of said first series of reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• a second sensor that detects a leading edge and a trailing edge in a rotational direction of the second series of reluctor of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• rotational direction discrimination means for discriminating the rotational direction of said internal combustion engine based on a phase relationship between the leading edge detection pulse generated by said first sensor and the leading edge detection pulse and the trailing edge detection pulse generated by said second sensor;
• and
• cylinder discrimination means for discriminating which cylinder of the internal combustion engine the pulse generated by said first sensor corresponds to, from a polarity or the number of pulses generated by said second sensor between when said first sensor generates one leading edge detection pulse and when said first sensor generates a next leading edge detection pulse,
• wherein polar arc angles of said first and said second series of reluctors, a positional relationship between said first and said second sensors, and a positional relationship between said first and said second series of reluctors are set so that said second sensor detects the leading edge or the trailing edge of the second series of one reluctor to generate one pulse while said first sensor sequentially detects at least one leading edge and at least one trailing edge of said first series of reluctors to generate the leading edge detection pulse and the trailing edge detection pulse.

A rotation information detector for detecting rotation information of a multi-cylinder internal combustion engine having two or more cylinders, comprising:

• a rotor in the form of an inductor having a first series of reluctors as many as cylinders of said internal combustion engine, that are provided correspondingly to each cylinder of said internal combustion engine and are rotated together with a crankshaft around a central axis of said crankshaft of said internal combustion engine, and a second series of at least one reluctor that is provided in a position shifted axially along said crankshaft relative to said first series of reluctors and is rotated together with said first series of reluctors;
• a first sensor that detects a leading edge and a trailing edge in a rotational direction of said first series of reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• a second sensor that detects a leading edge and a trailing edge in a rotational direction of the second series of reluctor of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• rotational direction discrimination means for discriminating the rotational direction of said internal combustion engine based on a phase relationship between the trailing edge detection pulse generated by said first sensor and the leading edge detection pulse and the trailing edge detection pulse generated by said second sensor;
• and
• cylinder discrimination means for discriminating which cylinder of the internal combustion engine the pulse generated by said first sensor corresponds to, from a polarity or the number of pulses generated by said second sensor between when said first sensor generates one trailing edge detection pulse and when said first sensor generates a next trailing edge detection pulse,
• wherein polar arc angles of said first and said second series of reluctors, a positional relationship between said first and said second sensors, and a positional relationship between said first and said second series of reluctors are set so that said second sensor detects the leading edge or the trailing edge of the second series of one reluctor to generate one pulse while said first sensor sequentially detects at least one leading edge and at least one trailing edge of said first series of reluctors to generate the leading edge detection pulse and the trailing edge detection pulse.

A rotation information detector for detecting rotation information including information on a rotational direction of a multi-cylinder internal combustion engine having a first cylinder and a second cylinder, comprising:

• a rotor in the form of an inductor having a first series of two reluctors that are placed at a substantially 180° interval in a rotational direction of a crankshaft of said internal combustion engine correspondingly to two cylinders of said internal combustion engine and are rotated together with said crankshaft around a central axis of said crankshaft, and a second series of at least one reluctor that is provided in a position shifted axially along said crankshaft relative to said first series of reluctors and is rotated together with said first series of reluctors;
• a first sensor that detects a leading edge and a trailing edge in each rotational direction of the first series of two reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• a second sensor that detects a leading edge and a trailing edge in a rotational direction of the second series of reluctor of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• rotational direction discrimination means for discriminating the rotational direction of said internal combustion engine based on a phase relationship between the leading edge detection pulse generated by said first sensor and the leading edge detection pulse and the trailing edge detection pulse generated by said second sensor;
• and
• cylinder discrimination means for discriminating which cylinder of said internal combustion engine the pulse generated by said first sensor corresponds to, using a feature that a polarity or the number of pulses generated by said second sensor between when said first sensor detects the leading edge of the first series of reluctor corresponding to the first cylinder of said internal combustion engine to generate the leading edge detection pulse and when said first sensor detects the leading edge of the first series of reluctor corresponding to the second cylinder of said internal combustion engine to generate the leading edge detection pulse is different from a polarity or the number of pulses generated by said second sensor between when said first sensor detects the leading edge of the first series of reluctor corresponding to the second cylinder of said internal combustion engine to generate the leading edge detection pulse and when said first sensor detects the leading edge of the first series of reluctor corresponding to the first cylinder of said internal combustion engine to generate the leading edge detection pulse,
• wherein polar arc angles of said first and said second series of reluctors, a positional relationship between said first and said second sensors, and a positional relationship between said first and said second series of reluctors are set so that said second sensor detects the leading edge or the trailing edge of the second series of one reluctor to generate either of the leading edge detection pulse or the trailing edge detection pulse while said first sensor sequentially detects the leading edge and the trailing edge of one of the first series of two reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, and so that said second sensor generates no pulse while said first sensor sequentially detects the leading edge and the trailing edge of the other of the first series of two reluctors to generate the leading edge detection pulse and the trailing edge detection pulse.

A rotation information detector for detecting rotation information including information on a rotational direction of a multi-cylinder internal combustion engine having a first cylinder and a second cylinder, comprising:

• a rotor in the form of an inductor having a first series of two reluctors that are placed at a substantially 180° interval in a rotational direction of a crankshaft of said internal combustion engine correspondingly to two cylinders of said internal combustion engine and are rotated together with said crankshaft around a central axis of said crankshaft, and a second series of at least one reluctor that is provided in a position shifted axially along said crankshaft relative to said first series of reluctors and is rotated together with said first series of reluctors;
• a first sensor that detects a leading edge and a trailing edge in each rotational direction of the first series of two reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• a second sensor that detects a leading edge and a trailing edge in a rotational direction of the second series of reluctor of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• rotational direction discrimination means for discriminating the rotational direction of said internal combustion engine based on a phase relationship between the trailing edge detection pulse generated by said first sensor and the leading edge detection pulse and the trailing edge detection pulse generated by said second sensor;
• and
• cylinder discrimination means for discriminating which cylinder of said internal combustion engine the pulse generated by said first sensor corresponds to, using a feature that a polarity or the number of pulses generated by said second sensor between when said first sensor of said signal generator detects the trailing edge of the first series of reluctor corresponding to the first cylinder of said internal combustion engine to generate the trailing edge detection pulse and when said first sensor detects the trailing edge of the first series of reluctor corresponding to the second cylinder of said internal combustion engine to generate the trailing edge detection pulse is different from a polarity or the number of pulses generated by said second sensor between when said first sensor detects the trailing edge of the first series of reluctor corresponding to the second cylinder of said internal combustion engine to generate the trailing edge detection pulse and when said first sensor detects the trailing edge of the first series of reluctor corresponding to the first cylinder of said internal combustion engine to generate the trailing edge detection pulse,
• wherein polar arc angles of said first and said second series of reluctors, a positional relationship between said first and said second sensors, and a positional relationship between said first and said second series of reluctors are set so that said second sensor detects the leading edge or the trailing edge of the second series of one reluctor to generate either of the leading edge detection pulse or the trailing edge detection pulse while said first sensor sequentially detects the leading edge and the trailing edge of one of the first series of two reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, and so that said second sensor generates no pulse while said first sensor sequentially detects the leading edge and the trailing edge of the other of the first series of two reluctors to generate the leading edge detection pulse and the trailing edge detection pulse.

A rotation information detector for detecting rotation information including information on a rotational direction of a multi-cylinder internal combustion engine having first to third cylinders, comprising:

• a rotor in the form of an inductor having a first series of three reluctors that are placed at substantially 120° intervals in a rotational direction of a crankshaft of said internal combustion engine correspondingly to three cylinders of said internal combustion engine and are rotated together with said crankshaft around a central axis of said crankshaft, and a second series of at least one reluctor that is provided in a position shifted axially along said crankshaft relative to said first series of reluctors and is rotated together with said first series of reluctors;
• a first sensor that detects a leading edge and a trailing edge in a rotational direction of each of the first series of three reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• a second sensor that detects a leading edge and a trailing edge in a rotational direction of each of the second series of two reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• rotational direction discrimination means for discriminating the rotational direction of said internal combustion engine based on a phase relationship between the leading edge detection pulse generated by said first sensor and the leading edge detection pulse and the trailing edge detection pulse generated by said second sensor;
• and
• cylinder discrimination means for discriminating which cylinder of said internal combustion engine the pulse generated by said first sensor corresponds to, using a feature that the number of pulses generated by said second sensor between when said first sensor detects the leading edge of the first series of reluctor corresponding to the first cylinder of said internal combustion engine to generate the leading edge detection pulse and when said first sensor detects the leading edge of the first series of reluctor corresponding to the second cylinder of said internal combustion engine to generate the leading edge detection pulse is different from the number of pulses generated by said second sensor between when said first sensor detects the leading edge of the first series of reluctor corresponding to the second cylinder of said internal combustion engine to generate the leading edge detection pulse and when said first sensor detects the leading edge of the first series of reluctor corresponding to the third cylinder of said internal combustion engine to generate the leading edge detection pulse, and different from the number of pulses generated by said second sensor between when said first sensor detects the leading edge of the first series of reluctor corresponding to the third cylinder of said internal combustion engine to generate the leading edge detection pulse and when said first sensor detects the leading edge of the first series of reluctor corresponding to the first cylinder of said internal combustion engine to generate the leading edge detection pulse,
• wherein polar arc angles of said first and said second series of reluctors, a positional relationship between said first and said second sensors, and a positional relationship between said first and said second series of reluctors are set so that said second sensor detects the leading edge or the trailing edge of the second series of one reluctor to generate the leading edge detection pulse or the trailing edge detection pulse while said first sensor sequentially detects the leading edge and the trailing edge of one of the first series of three reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, so that said second sensor detects the leading edge and the trailing edge of the second series of another reluctor to generate the leading edge detection pulse or the trailing edge detection pulse while said first sensor sequentially detects the leading edge and the trailing edge of another of the first series of three reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, and so that said second sensor detects no pulse while said first sensor sequentially detects the leading edge and the trailing edge of further one of said first series of three reluctors to generate the leading edge detection pulse and the trailing edge detection pulse.

A rotation information detector for detecting rotation information including information on a rotational direction of a multi-cylinder internal combustion engine having first to third cylinders, comprising:

• a rotor in the form of an inductor having a first series of three reluctors that are placed at substantially 120° intervals in a rotational direction of a crankshaft of said internal combustion engine correspondingly to three cylinders of said internal combustion engine and are rotated together with said crankshaft around a central axis of said crankshaft, and a second series of at least one reluctor that is provided in a position shifted axially along said crankshaft relative to said first series of reluctors and is rotated together with said first series of reluctors;
• a first sensor that detects a leading edge and a trailing edge in a rotational direction of each of the first series of three reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• a second sensor that detects a leading edge and a trailing edge in a rotational direction of each of the second series of two reluctors of said rotor to generate a leading edge detection pulse and a trailing edge detection pulse having different polarities;
• rotational direction discrimination means for discriminating the rotational direction of said internal combustion engine based on a phase relationship between the trailing edge detection pulse generated by said first sensor and the leading edge detection pulse and the trailing edge detection pulse generated by said second sensor;
• and
• cylinder discrimination means for discriminating which cylinder of said internal combustion engine the pulse generated by said first sensor corresponds to, using a feature that the number of pulses generated by said second sensor between when said first sensor of said signal generator detects the trailing edge of the first series of reluctor corresponding to the first cylinder of said internal combustion engine to generate the trailing edge detection pulse and when said first sensor detects the trailing edge of the first series of reluctor corresponding to the second cylinder of said internal combustion engine to generate the trailing edge detection pulse is different from the number of pulses generated by said second sensor between when said first sensor detects the trailing edge of the first series of reluctor corresponding to the second cylinder of said internal combustion engine to generate the trailing edge detection pulse and when said first sensor detects the trailing edge of the first series of reluctor corresponding to the third cylinder of said internal combustion engine to generate the trailing edge detection pulse, and different from the number of pulses generated by said second sensor between when said first sensor detects the trailing edge of the first series of reluctor corresponding to the third cylinder of said internal combustion engine to generate the trailing edge detection pulse and when said first sensor detects the trailing edge of the first series of reluctor corresponding to the first cylinder of said internal combustion engine to generate the trailing edge detection pulse,
• wherein polar arc angles of said first and said second series of reluctors, a positional relationship between said first and said second sensors, and a positional relationship between said first and said second series of reluctors are set so that said second sensor detects the leading edge or the trailing edge of the second series of one reluctor to generate the leading edge detection pulse or the trailing edge detection pulse while said first sensor sequentially detects the leading edge and the trailing edge of one of the first series of three reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, so that said second sensor detects the leading edge and the trailing edge of the second series of another reluctor to generate the leading edge detection pulse or the trailing edge detection pulse while said first sensor sequentially detects the leading edge and the trailing edge of another of the first series of three reluctors to generate the leading edge detection pulse and the trailing edge detection pulse, and so that said second sensor detects no pulse while said first sensor sequentially detects the leading edge and the trailing edge of further one of said first series of three reluctors to generate the leading edge detection pulse and the trailing edge detection pulse.