Abnormality diagnosis system and control system for internal combustion engine

• US 20080306648A1
• Filed: 02/29/2008
• Published: 12/11/2008
• Est. Priority Date: 04/23/2007
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Takahashi, Tomohiro
• Granted Patent: US 8,280,575 B2
• Time in Patent Office: Days
• US Class Current: 701/29
• CPC Class Codes: F02D 2041/224 Diagnosis of the fuel system
• CPC Class Codes: F02D 2250/31 Control of the fuel pressure
• CPC Class Codes: F02D 41/0007 for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02D 41/0047 Controlling exhaust gas recirculation [EGR] temperature control with cooler in recirculation circuit F02M26/33
• CPC Class Codes: F02D 41/221 relating to the failure of actuators or electrically driven elements
• CPC Class Codes: F02D 41/3845 by controlling the flow into the common rail, e.g. the amount of fuel pumped
• CPC Class Codes: G01M 15/09 by monitoring pressure in fluid ducts, e.g. in lubrication or cooling parts

Abstract

An ECU (60) for an engine (10, 70) monitors a change of an actual fuel pressure (NPC), when a target fuel pressure (PFIN) is changed stepwise. In one abnormality, the time required for the actual fuel pressure to reach the target fuel pressure is equal to that when an actuator (34) operates normally. However, the maximum value of a differential value (dNPC/dt) with respect to time of the actual fuel pressure is different from that when the actuator operates normally. For this reason, a normal range is set in advance for the maximum value of the differential value with respect to time of the actual fuel pressure and when the maximum value of the differential value with respect to time of the actual fuel pressure is out of the normal range, it is determined that the actuator operates abnormally.

Claims

1. An abnormality diagnosis system for an internal combustion engine having an actuator operable to control a controlled variable of an object to be controlled when fuel is converted to rotational energy, the abnormality diagnosis system comprising:

monitoring means for monitoring a change of an operating quantity or the controlled variable of the actuator in a process changing to a target value of the operating quantity or the controlled variable under condition in which the target value is changed; and

determination means for determining presence or absence of an abnormality in a response characteristic of the actuator based on the monitored change.

2. The abnormality diagnosis system as claimed in claim 1, wherein:

the monitoring means includes means for quantifying a change with respect to time of the operating quantity or the controlled variable of the actuator based on a detection value of the operating quantity or the controlled variable of the actuator before reaching the target value; and

the determination means determines the presence or absence of an abnormality in response characteristic of the actuator based on the quantified value.

3. The abnormality diagnosis system as claimed in claim 2, wherein:

the quantified quantity is a quantity corresponding to a differential value with respect to time of the operating quantity or the controlled variable of the actuator in a specified period.

4. The abnormality diagnosis system as claimed in claim 1, further comprising:

means for changing the target value forcibly.

5. The abnormality diagnosis system as claimed in claim 1, wherein:

the actuator controls a state quantity of fluid to be supplied to combustion in the internal combustion engine.

6. The abnormality diagnosis system as claimed in claim 1, wherein:

the internal combustion engine includes a fuel injection valve for injecting fuel accumulated in an accumulator chamber in a state of high pressure;

the actuator is a fuel pump for pressure-feeding the fuel accumulated in the accumulator chamber; and

the operating quantity or the controlled variable of the actuator is pressure of the fuel in the accumulator chamber as the controlled variable of the object to be controlled.

7. The abnormality diagnosis system as claimed in claim 1, wherein:

the internal combustion engine includes an exhaust recirculation passage for recirculating exhaust gas of an exhaust system to an intake system and a valve for controlling a cross-sectional area of the exhaust recirculation passage; and

the actuator is the valve.

8. The abnormality diagnosis system as claimed in claim 1, wherein:

the internal combustion engine includes a turbocharger capable of controlling flow characteristic of exhaust gas upstream of a turbine wheel disposed in an exhaust system;

the actuator is the turbocharger; and

the operating quantity or the controlled variable of the actuator is a boost pressure as a controlled variable of an object to be controlled.

9. The abnormality diagnosis system as claimed in claim 2, wherein:

the monitoring means changes the target value in stepwise to monitor the change of the operating quantity or the controlled variable of the actuator; and

the determination means determines the presence or absence of an abnormality based on whether the quantified value exceeds a predetermined normal range in response to a stepwise change of the target value.

10. A control system of an internal combustion engine comprising:

the diagnosis system as claimed in claim 1; and

the actuator as claimed in claim 1.

11. An abnormality diagnosis system for an internal combustion engine having and actuator operable to control a controlled variable of an objected to be controlled when fuel is converted to rotational energy, the abnormality diagnosis system comprising:

means for quantifying a change with respect to time of an operating quantity or the controlled variable of the actuator based on a plurality of detection values of the operating quantity or the controlled variable under condition in which a target value of the operating quantity or the controlled variable is changed; and

determination means for determining presence or absence of an abnormality in response characteristic of the actuator based on the quantified quantity.

12. The abnormality diagnosis system as claimed in claim 11, wherein:

the quantified quantity is a quantity corresponding to a differential value with respect to time of the operating quantity or the controlled variable of the actuator in a specified period.

13. The abnormality diagnosis system as claimed in claim 11, further comprising:

means for changing the target value forcibly.

14. The abnormality diagnosis system as claimed in claim 11, wherein:

the actuator controls a state quantity of fluid to be supplied to combustion in the internal combustion engine.

15. The abnormality diagnosis system as claimed in claim 11, wherein:

the internal combustion engine includes a fuel injection valve for injecting fuel accumulated in an accumulator chamber in a state of high pressure;

the actuator is a fuel pump for pressure-feeding the fuel accumulated in the accumulator chamber; and

the operating quantity or the controlled variable of the actuator is pressure of the fuel in the accumulator chamber as the controlled variable of the object to be controlled.

16. The abnormality diagnosis system as claimed in claim 11, wherein:

the internal combustion engine includes an exhaust recirculation passage for recirculating exhaust gas of an exhaust system to an intake system and a valve for controlling a cross-sectional area of the exhaust recirculation passage; and

the actuator is the valve.

17. The abnormality diagnosis system as claimed in claim 11, wherein:

the internal combustion engine includes a turbocharger capable of controlling flow characteristic of exhaust gas upstream of a turbine wheel disposed in an exhaust system;

the actuator is the turbocharger; and

the operating quantity or the controlled variable of the actuator is a boost pressure as a controlled variable of an object to be controlled.

18. The abnormality diagnosis system as claimed in claim 11, wherein:

the monitoring means changes the target value in stepwise to monitor the change of the operating quantity or the controlled variable of the actuator; and

the determination means determines the presence or absence of an abnormality based on whether the quantified value exceeds a predetermined normal range in response to a stepwise change of the target value.

19. A control system of an internal combustion engine comprising:

the diagnosis system as claimed in claim 11; and

the actuator as claimed in claim 11.