Control device for internal combustion engine and method for determining misfire in internal combustion engine

• US 7,210,456 B2
• Filed: 07/08/2004
• Issued: 05/01/2007
• Est. Priority Date: 08/06/2003
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Moriya, Hidenori, Miwa, Kouhei
• Primary Examiner(s): HUYNH, HAI H
• Application Number:
  US10/566,604
• Publication Number:
  US 20060217872A1
• Time in Patent Office: 1,027 Days
• Field of Search: 123435-436, 731/181, 731/182
• US Class Current: 123/435
• CPC Class Codes: F02D 2200/1015 Engines misfires
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 41/1497 With detection of the mechanical response of the engine
• CPC Class Codes: G01M 15/08 by monitoring pressure in cylinders
• CPC Class Codes: G01M 15/11 by detecting misfire

Abstract

An internal combustion engine (1) generates power by burning an air-fuel mixture in a combustion chamber (3). The internal combustion engine (1) is provided with an in-cylinder pressure sensor (15) and an ECU (20). The ECU 20 calculates at two predetermined points control parameters each of which is a product of an in-cylinder pressure detected by the in-cylinder pressure sensor (15) and a value obtained by exponentiating an in-cylinder volume at the time of detecting the in-cylinder pressure by a predetermined index number, as well as determines a misfire condition in the combustion chamber (3) based on the difference component in the control parameters between the two predetermined points.

Claims

1. A control device for an internal combustion engine that generates power by burning an air-fuel mixture in a cylinder, comprising:

in-cylinder pressure detecting means;

calculating means that calculates a control parameter based on an in-cylinder pressure detected by the in-cylinder pressure detecting means and an in-cylinder volume at the time of detecting the in-cylinder pressure; and

misfire determining means that determines a misfire condition in the cylinder based upon the control parameter calculated by the calculating means, wherein;

the control parameter is a product of the in-cylinder pressure detected by the in-cylinder pressure detecting means and a value obtained by exponentiating the in-cylinder volume at the time of detecting the in-cylinder pressure by a predetermined index number;

the calculating means calculates the control parameters in two predetermined points; and

the misfire determining means determines that an inside of the cylinder is in a misfire condition by comparing a difference component in the control parameters between the two predetermined points with a predetermined threshold value.

2. The control device for the internal combustion engine according to claim 1, wherein:

the misfire determining means determines that the inside of the cylinder is in a half-misfire condition when the difference component in the control parameters between the two predetermined points is below a first threshold value.

3. The control device for the internal combustion engine according to claim 2, wherein:

when the misfire determining means determines that the inside of the cylinder is in the half-misfire condition, at least one of a throttle opening, a fuel injection quantity, an opened/closed timing of an intake valve or an exhaust valve, and an exhaust gas recirculating rate is corrected in such a way as to restrain a subsequent misfire.

4. The control device for the internal combustion engine according to claim 3, wherein:

the misfire determining means that the inside of the cylinder is in a complete-misfire condition in a case where after the correction is made for a predetermined time, the difference component in the control parameters between the two predetermined points is below the first threshold value and also below a second threshold value, which is smaller than the first threshold value.

5. The control device for the internal combustion engine according to claim 1, wherein:

one of the two predetermined points is set at a point after an intake valve opens and also before combustion starts, and the other is set at a point after the combustion starts and also before an exhaust valve opens.

6. A method for determining a misfire in an internal combustion engine that generates power by burning an air-fuel mixture in a cylinder comprising:

(a) a step of detecting an in-cylinder pressure;

(b) a step of calculating a control parameter based on the in-cylinder pressure detected in the step (a) and an in-cylinder volume at the time of detecting the in-cylinder pressure; and

(c) a step of determining a misfire condition in the cylinder based on the control parameter calculated in the step (b), wherein;

the control parameter to be calculated in the step (b) is a product of the in-cylinder pressure detected in the step (a) and a value obtained by exponentiating the in-cylinder volume at the time of detecting the in-cylinder pressure by a predetermined index number,

in the step (b), the control parameters are calculated in two predetermined points; and

in the step (c), it is determined that an inside of the cylinder is in a misfire condition by comparing a difference component in the control parameters between the two predetermined points with a predetermined threshold value.

7. The method for determining the misfire in the internal combustion engine according to claim 6, wherein:

in the step (c), it is determined that the inside of the cylinder is in a half-misfire condition when the difference component in the control parameters between the two predetermined points is below a first threshold value.

8. The method for determining the misfire for the internal combustion engine according to claim 7, further comprising:

(d) a step of correcting at least one of a throttle opening, a fuel injection quantity, an opened/closed timing of an intake valve or an exhaust valve, and an exhaust gas recirculating rate in such a way as to restrain a subsequent misfire when it is determined in the step (c) that the inside of the cylinder is in the half-misfire condition.

9. The method for determining the misfire for the internal combustion engine according to claim 8, further comprising:

(e) a step of determining that the inside of the cylinder is in a complete-misfire condition in a case where after the correction in the step (d) is made for a predetermined time, the difference component in the control parameters between the two predetermined points is below the first threshold value and also below a second threshold value, which is smaller than the first threshold value.

10. The method for determining the misfire for the internal combustion engine according to claim 6, wherein:

one of the two predetermined points is set at a point after an intake valve opens and also before combustion starts, and the other is set at a point after the combustion starts and also before an exhaust valve opens.