Crank angle detecting system for internal combustion engines
First Claim
1. A system for detecting a maximum pressure crank angle at which the pressure within a firing cylinder of an internal combustion engine is maximum and whereby detecting offset of said maximum pressure crank angle from a predetermined target angle, comprising:
- first means for monitoring engine crank angle to produce first signals indicative of first, second and third crank angles within a range defined in the vicinity of said target angle;
second means for monitoring engine crank angle to produce a second signal indicative of a fourth crank angle outside of said range;
third means for monitoring pressure in said firing cylinder, said third means being responsive to said first and second signals, for producing a pressure value indicative of pressure within said firing cylinder at said first, second, third, and fourth crank angles;
fourth means, for comparing said pressure values at said first, second, and third crank angles, for projecting said maximum pressure crank angle when said maximum pressure crank angle is included within said range; and
fifth means for deriving direction and magnitude of offset of said maximum pressure crank angle to said target angle based on said pressure values at said first, second, third, and forth angles when said maximum pressure crank angle is not included within said range.
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Accused Products
Abstract
A crank angle detecting system for an internal combustion engine is provided which comprises a pressure sensor, a crank angle sensor, and crank angle judging device. The pressure sensor is adaptable for sensing pressure within the cylinder and provides pressure signals to the crank angle judging device which are representative of cylinder pressure within the cylinder at three predetermined crank angles in a range defined in the vicinity of a crank angle at which maximum torque is generated. The crank angle judging device determines the crank angle at which the maximum pressure within the cylinder occurs according to a quadratic equation employing the sensed cylinder pressures. The crank angle judging device then judges whether the crank angle at which maximum pressure is presumed to occur is advanced or retarded relative to the best crank angle. The ignition timing is corrected so as to be advanced or retarded according to the resulting judgments.
25 Citations
27 Claims
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1. A system for detecting a maximum pressure crank angle at which the pressure within a firing cylinder of an internal combustion engine is maximum and whereby detecting offset of said maximum pressure crank angle from a predetermined target angle, comprising:
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first means for monitoring engine crank angle to produce first signals indicative of first, second and third crank angles within a range defined in the vicinity of said target angle; second means for monitoring engine crank angle to produce a second signal indicative of a fourth crank angle outside of said range; third means for monitoring pressure in said firing cylinder, said third means being responsive to said first and second signals, for producing a pressure value indicative of pressure within said firing cylinder at said first, second, third, and fourth crank angles; fourth means, for comparing said pressure values at said first, second, and third crank angles, for projecting said maximum pressure crank angle when said maximum pressure crank angle is included within said range; and fifth means for deriving direction and magnitude of offset of said maximum pressure crank angle to said target angle based on said pressure values at said first, second, third, and forth angles when said maximum pressure crank angle is not included within said range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A system for detecting a maximum pressure crank angle at which the pressure within a firing cylinder of an internal combustion engine is maximum and whereby detecting offset of said maximum pressure angle from a predetermined target angle, comprising:
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first means for monitoring engine crank angle to produce first signals indicative of first, second, and third crank angles within a range defined in the vicinity of said target angle; second means for monitoring pressure in said firing cylinder, said second means being responsive to said first signals, for producing a pressure value indicative of the pressure within said firing cylinder at said first, second, and third angles within said range; third means, for comparing said pressure values at said first, second, and third angles, for projecting said maximum pressure angle when said maximum pressure angle is included within said range; fourth means for deriving direction and magnitude of offset of said maximum pressure angle to said target angle based on said pressure value at said first and third angles when said maximum pressure angle is not included within said range; and fifth means for discriminating whether said maximum pressure angle is advanced relative to said target angle missfire, by comparing said pressure value at said first angle with a reference pressure value when said maximum pressure angle is not included within said range. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A crank angle detecting system for an internal combustion engine having a plurality of cylinders and a crankshaft comprising:
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first means for detecting the angular position of a crankshaft; second means for sensing pressure within the cylinder at each of three or more predetermined crank angular positions in a range defined in the vicinity of a target crankshaft angular position for maximum pressure to occur and at a predetermined crankshaft angular position outside of said range; third means for judging whether a crankshaft angular position θ
pmax at which pressure within the cylinder is maximum can be calculated or not according to variations of the pressure within said range;fourth means for determining whether said θ
pmax is advanced or retarded relative to said target angle according to variations of the pressure within said range and at said position outside of said range when said calculation is impossible; andfifth means for calculating said crankshaft angular position θ
pmax when said position θ
pmax is within said range. - View Dependent Claims (23, 24, 25)
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26. A crank angle detecting system for an internal combustion engine having a plurality of cylinders and a crankshaft comprising:
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first means for detecting the angular position of a crankshaft; second means for sensing pressure within a cylinder at each of three or more predetermined crank angular positions in a range defined in the vicinity of a predetermined target crankshaft angular position for the maximum pressure to occur and at a predetermined crankshaft angular position outside of the range; third means for judging whether a crankshaft angular position θ
pmax at which pressure within the cylinder is maximum can be calculated or not according to variations of pressure within said range; andfourth means for adjusting an ignition timing so as to enable said θ
pmax to be calculated by comparing magnitude of the pressure within said range with that at said position outside of said range.
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27. An ignition timing control system for detecting a crank angle at which maximum pressure occurs within a firing cylinder of an internal combustion engine and detecting offset of said maximum pressure angle from a predetermined target angle, comprising:
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first means for monitoring engine crank angle to produce first signals indicative of first, second and third crank angle within a range defined in the vicinity of said target point; second means for monitoring engine crank angle to produce a second signal indicative of a fourth crank angle outside of said range; third means for monitoring pressure in said firing cylinder, said third means being responsive to said first and second signals, for producing a pressure value indicative of the pressure within said firing cylinder at said first, second, third, and fourth angle; fourth means, for comprising said pressure values at said first, second, and third angles, for projecting said maximum pressure angle when said maximum pressure angle is included within said range; fifth means for deriving direction and magnitude of offset of maximum pressure angle to said target angle based on said pressure values at said first, second, third, and forth angles when said maximum pressure angle is not included within said range; sixth means for adjusting an ignition timing so as to enable said maximum pressure to be projected according said direction and magnitude of offset derived by fifth means; and seventh means for controlling the ignition timing by calculating the angle between said maximum pressure angle projected by fourth means and said target angle.
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Specification