ABNORMALITY DIAGNOSIS APPARATUS FOR EXHAUST GAS RECIRCULATION APPARATUS AND ABNORMALITY DIAGNOSIS METHOD FOR EXHAUST GAS RECIRCULATION APPARATUS

• US 20110011378A1
• Filed: 03/19/2009
• Published: 01/20/2011
• Est. Priority Date: 03/28/2008
• Status: Abandoned Application

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Nakamura, Takashi
• Application Number:
  US12/935,142
• Publication Number:
  US 20110011378A1
• Time in Patent Office: Days
• US Class Current: 123/568.16
• CPC Class Codes: F02D 41/0055 Special engine operating conditions, e.g. for regeneration of exhaust gas treatment apparatus
• CPC Class Codes: F02D 41/123 the fuel injection being cut-off
• CPC Class Codes: F02D 41/1495 Detection of abnormalities in the air/fuel ratio feedback system
• CPC Class Codes: F02M 26/49 Detecting, diagnosing or indicating an abnormal function of the EGR system

Abstract

An EGR apparatus includes an EGR passage that connects an intake passage and an exhaust passage of an internal combustion engine in order to introduce a part of an exhaust gas into the intake passage, and an EGR valve for adjusting the amount of exhaust gas flowing through the passage. An oxygen concentration sensor that outputs a continuous value corresponding to the oxygen concentration of the exhaust gas flowing through the exhaust passage is provided in the exhaust passage. Valve-opening driving is performed on the EGR valve during fuel cut processing for halting the fuel supply of the internal combustion engine, and when a variation range of the output value of the oxygen concentration sensor accompanying the valve-opening driving is smaller than a predetermined value, it is determined that an abnormality is present in the EGR apparatus.

Claims

1. An abnormality diagnosis apparatus applied to an exhaust gas recirculation apparatus having an exhaust gas recirculation passage that connects an intake passage and an exhaust passage of an internal combustion engine in order to introduce a part of an exhaust gas into the intake passage and an exhaust gas amount control valve that adjusts an amount of the exhaust gas flowing through the exhaust gas recirculation passage, comprising:

an oxygen concentration sensor that is provided in the exhaust passage and outputs a continuous value corresponding to an oxygen concentration of the exhaust gas flowing through the exhaust passage; and

an EGR abnormality diagnosis unit that performs valve-opening driving on the exhaust gas amount control valve during fuel cut processing for halting a fuel supply of the internal combustion engine wherein at the start of the fuel cut processing, the valve is closed, and when the valve-opening driving is executed on the valve at a predetermined timing, executes abnormality diagnosis processing for determining that an abnormality is present in the exhaust gas recirculation apparatus when a variation range of an output value of the oxygen concentration sensor accompanying the valve-opening driving is smaller than a predetermined value.

3. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 1, wherein the EGR abnormality diagnosis unit performs the valve-opening driving on the exhaust gas amount control valve on condition that respective interiors of a combustion chamber and the exhaust passage of the internal combustion engine have been filled with air.

4. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 3, wherein the abnormality diagnosis unit determines that the respective interiors of the combustion chamber and the exhaust passage have been filled with air in accordance with an operating condition of the internal combustion engine.

5. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 4, wherein the abnormality diagnosis unit uses an engine rotation speed as the operating condition of the internal combustion engine.

6. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 1, wherein the EGR abnormality diagnosis unit determines that an abnormality is present in the exhaust gas recirculation apparatus on the basis of the output value of the oxygen concentration sensor following the elapse of a predetermined time period from the start of the valve-opening driving performed on the exhaust gas amount control valve.

7. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 1, wherein the EGR abnormality diagnosis unit determines that an operation defect has occurred in the exhaust gas amount control valve as the abnormality in the exhaust gas recirculation apparatus.

8. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 1, further comprising:

a sensor abnormality diagnosis unit that executes abnormality diagnosis processing for determining that an abnormality is present in the oxygen concentration sensor on the basis of the output value of the oxygen concentration sensor during the fuel cut processing; and

an abnormality diagnosis selection unit that selects one of the abnormality diagnosis processing performed by the EGR abnormality diagnosis unit and the abnormality diagnosis processing performed by the sensor abnormality diagnosis unit.

9. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 8, wherein the abnormality diagnosis selection unit sets an order of precedence in relation to the abnormality diagnosis processing performed by the EGR abnormality diagnosis unit and the abnormality diagnosis processing performed by the sensor abnormality diagnosis unit, determines establishment of an execution condition of the abnormality diagnosis processing in accordance with the order of precedence, and permits execution of the abnormality diagnosis processing for which the execution condition is established.

10. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 9, wherein, when the execution condition of the abnormality diagnosis processing having a higher order of precedence is established while the other abnormality diagnosis processing is underway, the abnormality diagnosis selection unit stops the abnormality diagnosis processing.

11. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 9, wherein the abnormality diagnosis selection unit sets the order of precedence of the abnormality diagnosis processing performed by the sensor abnormality diagnosis unit to be higher than the order of precedence of the abnormality diagnosis processing performed by the EGR abnormality diagnosis unit.

12. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 8, wherein, when the abnormality diagnosis processing performed by the EGR abnormality diagnosis unit is executed first during a period extending from the start to the completion of the fuel cut processing, the abnormality diagnosis selection unit permits the abnormality diagnosis processing performed by the sensor abnormality diagnosis unit after a predetermined time period has elapsed following stoppage of the abnormality diagnosis.

2. An abnormality diagnosis apparatus applied to an exhaust gas recirculation apparatus having an exhaust gas recirculation passage that connects an intake passage and an exhaust passage of an internal combustion engine in order to introduce a part of an exhaust gas into the intake passage and an exhaust gas amount control valve that adjusts an amount of the exhaust gas flowing through the exhaust gas recirculation passage, comprising:

an oxygen concentration sensor that is provided in the exhaust passage and outputs a continuous value corresponding to an oxygen concentration of the exhaust gas flowing through the exhaust passage; and

an EGR abnormality diagnosis unit that performs valve-opening driving on the exhaust gas amount control valve during fuel cut processing for halting a fuel supply of the internal combustion engine, and executes abnormality diagnosis processing for determining that an abnormality is present in the exhaust gas recirculation apparatus when a deviation between an output value of the oxygen concentration sensor following the valve-opening driving and a determination value equals or exceeds a predetermined value.

15. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 2, wherein the EGR abnormality diagnosis unit performs the valve-opening driving on the exhaust gas amount control valve on condition that respective interiors of a combustion chamber and the exhaust passage of the internal combustion engine have been filled with air.

16. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 15, wherein the abnormality diagnosis unit determines that the respective interiors of the combustion chamber and the exhaust passage have been filled with air in accordance with an operating condition of the internal combustion engine.

17. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 16, wherein the abnormality diagnosis unit uses an engine rotation speed as the operating condition of the internal combustion engine.

18. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 2, wherein the EGR abnormality diagnosis unit determines that an abnormality is present in the exhaust gas recirculation apparatus on the basis of the output value of the oxygen concentration sensor following the elapse of a predetermined time period from the start of the valve-opening driving performed on the exhaust gas amount control valve.

19. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 2, wherein the EGR abnormality diagnosis unit determines that an operation defect has occurred in the exhaust gas amount control valve as the abnormality in the exhaust gas recirculation apparatus.

20. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 2, further comprising:

a sensor abnormality diagnosis unit that executes abnormality diagnosis processing for determining that an abnormality is present in the oxygen concentration sensor on the basis of the output value of the oxygen concentration sensor during the fuel cut processing; and

an abnormality diagnosis selection unit that selects one of the abnormality diagnosis processing performed by the EGR abnormality diagnosis unit and the abnormality diagnosis processing performed by the sensor abnormality diagnosis unit.

21. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 20, wherein the abnormality diagnosis selection unit sets an order of precedence in relation to the abnormality diagnosis processing performed by the EGR abnormality diagnosis unit and the abnormality diagnosis processing performed by the sensor abnormality diagnosis unit, determines establishment of an execution condition of the abnormality diagnosis processing in accordance with the order of precedence, and permits execution of the abnormality diagnosis processing for which the execution condition is established.

22. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 21, wherein, when the execution condition of the abnormality diagnosis processing having a higher order of precedence is established while the other abnormality diagnosis processing is underway, the abnormality diagnosis selection unit stops the abnormality diagnosis processing.

23. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 21, wherein the abnormality diagnosis selection unit sets the order of precedence of the abnormality diagnosis processing performed by the sensor abnormality diagnosis unit to be higher than the order of precedence of the abnormality diagnosis processing performed by the EGR abnormality diagnosis unit.

24. The abnormality diagnosis apparatus for an exhaust gas recirculation apparatus according to claim 20, wherein, when the abnormality diagnosis processing performed by the EGR abnormality diagnosis unit is executed first during a period extending from the start to the completion of the fuel cut processing, the abnormality diagnosis selection unit permits the abnormality diagnosis processing performed by the sensor abnormality diagnosis unit after a predetermined time period has elapsed following stoppage of the abnormality diagnosis.

13. An abnormality diagnosis method for an exhaust gas recirculation apparatus having an exhaust gas recirculation passage that connects an intake passage and an exhaust passage of an internal combustion engine in order to introduce a part of an exhaust gas into the intake passage and an exhaust gas amount control valve that adjusts an amount of the exhaust gas flowing through the exhaust gas recirculation passage, comprising:

outputting a continuous value corresponding to an oxygen concentration of the exhaust gas flowing through the exhaust passage; and

performing valve-opening driving on the exhaust gas amount control valve during fuel cut processing for halting a fuel supply of the internal combustion engine wherein at the start of the fuel cut processing, the valve is closed, and, when the valve-opening driving is executed on the valve at a predetermined timing, determining that an abnormality is present in the exhaust gas recirculation apparatus when a variation range of an output value corresponding to the oxygen concentration of the exhaust gas flowing through the exhaust passage during the valve-opening driving is smaller than a predetermined value.

14. An abnormality diagnosis method for an exhaust gas recirculation apparatus having an exhaust gas recirculation passage that connects an intake passage and an exhaust passage of an internal combustion engine in order to introduce a part of an exhaust gas into the intake passage and an exhaust gas amount control valve that adjusts an amount of the exhaust gas flowing through the exhaust gas recirculation passage, comprising:

outputting a continuous value corresponding to an oxygen concentration of the exhaust gas flowing through the exhaust passage; and

performing valve-opening driving on the exhaust gas amount control valve during fuel cut processing for halting a fuel supply of the internal combustion engine, and determining that an abnormality is present in the exhaust gas recirculation apparatus when a deviation between an output value corresponding to the oxygen concentration of the exhaust gas flowing through the exhaust passage following the valve-opening driving and an expected value corresponding to an expected oxygen concentration following the elapse of a predetermined time period from the start of the fuel cut processing equals or exceeds a predetermined value.