Device for determining malfunction of an engine cylinder
First Claim
1. A device for determining a malfunction of a cylinder of an internal combustion engine including a plurality of cylinders, the device comprising:
- first detection means for detecting a first engine speed at a predetermined first crank angle, wherein the first crank angle is within a portion of a power stroke of a first cylinder, and a second engine speed at a predetermined second crank angle, wherein said second predetermined crank angle is within a corresponding portion of a power stroke of a second engine cylinder;
difference calculating means for calculating a difference between said first and second engine speeds;
misfire determining means for determining that a misfire has occurred in the engine cylinder in which the engine speed is smaller when said difference is larger than a predetermined limit;
malfunction determining means for determining that a malfunction has occurred in an engine cylinder when a frequency at which said misfire determining means determines that a misfire has occurred in the particular cylinder is larger than a predetermined frequency;
second detection means for detecting a current engine load; and
first changing means for changing at least one of said predetermined limit and said predetermined frequency in accordance with the current engine load.
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Accused Products
Abstract
A device for determining a malfunction of an engine cylinder of an internal combustion engine, comprising a first detection unit for detecting a first engine speed at a predetermined first crank angle, and a detecting second engine speed at a predetermined second crank angle, during a power stroke of two engine cylinders under a continuous combustion cycle, a difference calculating unit for calculating a difference between the first and second engine speeds, a misfire determining unit for determining that a misfire has occurred in a corresponding engine cylinder when the difference is outside a predetermined limit, a malfunction determining unit for determining that a malfunction has occurred in the corresponding engine cylinders when a frequency at which the misfire determining unit determines that a misfire has occurred is larger than a predetermined frequency, a second detection unit for detecting a current engine load, and a first changing unit for changing at least one of the predetermined limit and the predetermined frequency in accordance with the current engine load.
47 Citations
26 Claims
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1. A device for determining a malfunction of a cylinder of an internal combustion engine including a plurality of cylinders, the device comprising:
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first detection means for detecting a first engine speed at a predetermined first crank angle, wherein the first crank angle is within a portion of a power stroke of a first cylinder, and a second engine speed at a predetermined second crank angle, wherein said second predetermined crank angle is within a corresponding portion of a power stroke of a second engine cylinder; difference calculating means for calculating a difference between said first and second engine speeds; misfire determining means for determining that a misfire has occurred in the engine cylinder in which the engine speed is smaller when said difference is larger than a predetermined limit; malfunction determining means for determining that a malfunction has occurred in an engine cylinder when a frequency at which said misfire determining means determines that a misfire has occurred in the particular cylinder is larger than a predetermined frequency; second detection means for detecting a current engine load; and first changing means for changing at least one of said predetermined limit and said predetermined frequency in accordance with the current engine load. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A device for determining a malfunction of a cylinder of an internal combustion engine including a plurality of cylinders, the device comprising:
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first detection means for detecting a first engine speed at a predetermined first crank angle, wherein the first crank angle is within an initial portion of a power stroke of a cylinder, and a second engine speed at a predetermined second crank angle, wherein said second predetermined crank angle is within a latter portion of the power stroke of the same engine cylinder; difference calculating means for calculating a difference between said first and second engine speeds; misfire determining means for determining that a misfire has occurred in the engine cylinder in which the difference is smaller than a predetermined limit; malfunction determining means for determining that a malfunction has occurred in an engine cylinder when a frequency at which said misfire determining means determines that a misfire has occurred in the particular cylinder is larger than a predetermined frequency; second detection means for detecting a current engine driving condition; and stop means for stopping a determination by said misfire determining means, wherein said stop means stops a determination by said misfire determining means when the engine driving condition is a transient condition. - View Dependent Claims (24, 25, 26)
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Specification