Engine rotation information detection device

• US 20050120782A1
• Filed: 12/07/2004
• Published: 06/09/2005
• Est. Priority Date: 12/08/2003
• Status: Active Grant

• Current Assignee: Mahle International GmbH (MAHLE-STIFTUNG GmbH)
• Original Assignee: Kokusan Denki Company Limited (MAHLE-STIFTUNG GmbH)
• Inventors: Sato, Hiroyasu, Kishibata, Kazuyoshi, Kitagawa, Yuichi
• Granted Patent: US 7,032,440 B2
• Time in Patent Office: Days
• US Class Current: 73/114.260
• CPC Class Codes: F02D 41/009 using means for generating position or synchronisation signals
• CPC Class Codes: G01D 5/2013 by a movable ferromagnetic element, e.g. a core G01D5/2033 takes precedence
• CPC Class Codes: G01D 5/2457 Incremental encoders having reference marks
• CPC Class Codes: G01P 3/488 delivered by variable reluctance detectors
• CPC Class Codes: G01P 3/489 Digital circuits therefor

Abstract

An engine rotation information detection device including: a generator that rotates in synchronization with an engine to output an AC voltage; a pulse signal generator that detects reluctors of a rotor having many reluctors and one reluctor missing portion to generate a pulse; counting means that counts the number of detections of a zero point of a waveform of the AC voltage in each detection section, the detection section being a section between a crank angle position where the pulse signal generator detects an edge of each reluctor and a crank angle position where the pulse signal generator detects a next reluctor; and reference crank angle position identification means that specifies a detection section including the reluctor missing portion from a count value counted by the counting means and identifies a pulse generated at a reference crank angle position based on the specified detection section.

Claims

1. An engine rotation information detection device that detects rotation information including information on a reference crank angle position of an engine comprising:

signal generating device including a rotor in which one of n reluctors (n is an integer equal to or more than three) arranged at regular intervals in a rotational direction of a crankshaft of said engine is missed, a total of n-1 reluctors are arranged in said rotational direction, and a portion from which said one reluctor is missed is a reluctor missing portion, and a pulse signal generator that detects an edge of each of the n-1 reluctors provided on said rotor to generate a pulse, said pulse signal generator detecting an edge of any reluctor of said rotor to generate a pulse when a crank angle position of said engine matches said reference crank angle position;

a generator that rotates in synchronization with said crankshaft to output an n×

m-cycle AC voltage (m is an integer equal to or more than one);

counting means that counts the number of detections of a singular point of a waveform of said AC voltage in each detection section, said detection section being a section between a crank angle position where said pulse signal generator detects the edge of each reluctor to generate a pulse and a crank angle position where said pulse signal generator detects a next reluctor to generate a pulse; and

reference crank angle position identification means that uses a difference between a count value counted by said counting means in a detection section including said reluctor missing portion and a count value counted by said counting means in other detection sections to specify the detection section including the reluctor missing portion and identify a pulse generated at said reference crank angle position based on the specified detection section.

2. The engine rotation information detection device according to claim 1, wherein the singular point of the waveform of said AC voltage is a point at which said AC voltage reaches a predetermined threshold value level.

3. The engine rotation information detection device according to claim 1, wherein the singular point of the waveform of said AC voltage is a zero point of the waveform of said AC voltage.

4. The engine rotation information detection device according to claim 1, wherein the singular point of the waveform of said AC voltage is a peak point of the waveform of said AC voltage.

5. An engine rotation information detection device that detects rotation information including information on a reference crank angle position of an engine comprising:

a signal generating device including a rotor in which one of n reluctors (n is an integer equal to or more than three) arranged at regular intervals in a rotational direction of a crankshaft of said engine is missed, a total of n-1 reluctors are arranged in said rotational direction, and a portion from which said one reluctor is missed is a reluctor missing portion, and a pulse signal generator that detects a leading edge and a trailing edge in the rotational direction of each of said reluctors to generate a leading edge pulse and a trailing edge pulse paired with each other, said pulse signal generator detecting a leading edge or a trailing edge of any reluctor of said rotor to generate a pulse when a crank angle position of said engine matches said reference crank angle position;

a generator that rotates in synchronization with rotation of said crankshaft to output an n×

m-cycle AC voltage (m is an integer equal to or more than one);

a phase signal generating circuit that shapes a waveform of said AC voltage, and generates a phase signal that shows a first level during a period when a voltage of a half wave of one polarity of said AC voltage is a threshold value or more, and a second level during other periods;

a waveform shaping circuit that generates a crank angle pulse that keeps a predetermined level between when said pulse signal generator generates each leading edge pulse and when said pulse signal generator generates each trailing edge pulse paired with said leading edge pulse;

counting means that counts the number of detections of a phase to be detected in a detection section, said detection section being a section between a crank angle position corresponding to any edge of each crank angle pulse generated by said waveform shaping circuit and a crank angle position corresponding to any edge of a next crank angle pulse, and said phase to be detected being at least one of a phase in which a level of said phase signal changes from the first level to the second level and a phase in which the level of said phase signal changes from the second level to the first level; and

reference crank angle position identification means that uses a difference between a count value counted by said counting means in a detection section including said reluctor missing portion and a count value counted by said counting means in other detection sections to specify the detection section including the reluctor missing portion and identify a pulse generated at said reference crank angle position based on the specified detection section,

wherein a phase relationship between the phase signal and the series of pulses generated by the pulse signal generator is set so that said phase signal shows the first level when said waveform shaping circuit generates each crank angle pulse.

6. The engine rotation information detection device according to claim 5, further comprising rotational direction determination means that determines that said engine rotates forward when the level of said phase signal is the first level at the time of generation of the leading edge pulse and/or the trailing edge pulse by said pulse signal generator, and determines that said engine rotates in reverse when the level of said phase signal is the second level at the time of generation of the leading edge pulse and/or the trailing edge pulse by said pulse signal generator.

7. The engine rotation information detection device according to claim 5, further comprising:

abnormality detection means that detects whether an abnormality occurs in a signal system that obtains said phase signal; and

abnormal time reference crank angle position identification means that compares lengths of said detection sections successively appearing with rotation of said rotor to specify the detection section including said reluctor missing portion and identify a pulse generated at said reference crank angle position based on the specified detection section, when said abnormality detection means detects the abnormality in the signal system that obtains said phase signal.

8. The engine rotation information detection device according to claim 7, wherein said abnormality detection means is comprised so as to determine that there is an abnormality in the signal system that obtains said phase signal when no level change of said phase signal is detected across the plurality of detection sections successively appearing with rotation of said rotor.

9. An engine rotation information detection device that detects rotation information including information on a reference crank angle position of an engine comprising:

a signal generating device including a rotor in which one of n reluctors (n is an integer equal to or more than three) arranged at regular intervals in a rotational direction of a crankshaft of said engine is missed, a total of n-1 reluctors are arranged in said rotational direction, and a portion from which said one reluctor is missed is a reluctor missing portion, and a pulse signal generator that detects a leading edge and a trailing edge in the rotational direction of each of said reluctors to generate a leading edge pulse and a trailing edge pulse paired with each other, said pulse signal generator detecting a leading edge or a trailing edge of any reluctor of said rotor to generate a pulse when a crank angle position of said engine matches said reference crank angle position;

a generator that rotates in synchronization with rotation of said crankshaft to output an n×

m-cycle AC voltage (m is an integer equal to or more than one);

a phase signal generating circuit that shapes a waveform of said AC voltage, and generates a phase signal that shows a first level during a period when a voltage of a half wave of one polarity of said AC voltage is a threshold value or more, and a second level during other periods;

a waveform shaping circuit that generates a crank angle pulse that keeps a predetermined level between when said pulse signal generator generates each leading edge pulse and when said pulse signal generator generates a trailing edge pulse paired with said leading edge pulse;

counting means that counts the number of detections of a phase to be detected in a detection section, said detection section being a section between a crank angle position corresponding to any edge of each crank angle pulse generated by said waveform shaping circuit and a crank angle position corresponding to any edge of a next crank angle pulse, and said phase to be detected being at least one of a phase in which a level of said phase signal changes from the first level to the second level and a phase in which the level of said phase signal changes from the second level to the first level;

first reference crank angle position identification means that uses a difference between a count value counted by said counting means in a detection section including said reluctor missing portion and a count value counted by said counting means in other detection sections to specify the detection section including said reluctor missing portion and identify a pulse generated at said reference crank angle position based on the specified detection section, before a start of said engine is completed; and

second reference crank angle position identification means that compares lengths of said detection sections successively appearing with rotation of said rotor to specify the detection section including said reluctor missing portion and identify a pulse generated at said reference crank angle position based on the specified detection section, after the start of the engine is completed,

wherein a phase relationship between said phase signal and the series of pulses generated by said pulse signal generator is set so that said phase signal shows said first level when said waveform shaping circuit generates each crank angle pulse.

10. The engine rotation information detection device according to claim 9, wherein said second reference crank angle position identification means includes:

specific detection section prediction means that assigns pulse numbers to the series of crank angle pulses obtained from said waveform shaping circuit and predicts the detection section including said reluctor missing portion from said pulse numbers as the specific detection section; and

reluctor missing portion checking means that compares lengths of the specific detection section predicted by said specific detection section prediction means and a preceding detection section to check whether said specific detection section includes said reluctor missing portion.

11. The engine rotation information detection device according to claim 9, further comprising rotational direction determination means that determines that said engine rotates forward when the level of said phase signal is the first level at the time of generation of the leading edge pulse and/or the trailing edge pulse by said pulse signal generator, and determines that said engine rotates in reverse when the level of said phase signal is the second level at the time of generation of the leading edge pulse and/or the trailing edge pulse by said pulse signal generator.