ABNORMALITY DETERMINATION APPARATUS AND ABNORMALITY DETERMINATION METHOD FOR VALVE CHARACTERISTICS CHANGE MECHANISM

• US 20090288480A1
• Filed: 05/26/2009
• Published: 11/26/2009
• Est. Priority Date: 05/23/2008
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Noda, Minoru
• Granted Patent: US 7,921,711 B2
• Time in Patent Office: Days
• US Class Current: 73/114.790
• CPC Class Codes: F01L 1/344 changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
• CPC Class Codes: F01L 2001/186 Split rocking arms, e.g. rocker arms having two articulated parts and means for varying the relative position of these parts or for selectively connecting the parts to move in unison
• CPC Class Codes: F01L 2800/00 Methods of operation using a variable valve timing mechanism
• CPC Class Codes: F01L 2800/11 Fault detection, diagnosis
• CPC Class Codes: F02D 13/02 during engine operation
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 41/221 relating to the failure of actuators or electrically driven elements
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

To an electronic control unit is connected a shaft position detection sensor that outputs, as a shaft position detection value, a signal whose magnitude changes stepwise by a predetermined amount in correspondence with the position of a control shaft of a valve characteristics change mechanism. The electronic control unit stores in advance, as a determination reference value, the drive amount of an actuator at the time when the magnitude of the shaft position detection value changes. The electronic control unit performs normality determination to indicate that the valve characteristics change mechanism is operating normally when the drive amount at the time when the shaft position detection value changes along with driving of the actuator and the determination reference value correspond to each other, and performs abnormality determination to indicate that an abnormality is occurring in the valve characteristics change mechanism when the drive amount and the determination reference value do not correspond to each other.

Claims

1. An abnormality determination apparatus that determines whether or not a valve characteristics change mechanism is operating normally, in an internal combustion engine that includes the valve characteristics change mechanism that changes a maximum lift amount and a lift duration of an engine valve continuously in correspondence with a position of a control shaft, an actuator that drives the control shaft, and a drive amount detector that detects a drive amount of the actuator, and that the valve characteristics change mechanism is configured to change the maximum lift amount and the lift duration of the engine valve by controlling the actuator such that the drive amount approaches a target drive amount, the abnormality determination apparatus comprising:

a shaft position detection sensor that outputs, as a shaft position detection value, a signal whose magnitude changes stepwise by a predetermined amount in correspondence with the position of the control shaft; and

an abnormality determiner that stores in advance, as a determination reference value, the drive amount at the time when a magnitude of the shaft position detection value detected by the shaft position detection sensor changes,

the abnormality determiner performing normality determination to indicate that the valve characteristics change mechanism is operating normally when the drive amount detected when the shaft position detection value changes along with driving of the actuator and the determination reference value correspond to each other, and

the abnormality determiner performing abnormality determination to indicate that an abnormality is occurring in the valve characteristics change mechanism when the drive amount and the determination reference value do not correspond to each other.

2. The abnormality determination apparatus according to claim 1, wherein

the abnormality determiner performs normality determination to indicate that the valve characteristics change mechanism is operating normally if the shaft position detection value changes when the drive amount changes across the determination reference value along with driving of the actuator, and performs abnormality determination to indicate that an abnormality is occurring in the valve characteristics change mechanism if the shaft position detection value does not change when the drive amount changes across the determination reference value.

3. The abnormality determination apparatus according to claim 2, wherein

the abnormality determiner performs normality determination to indicate that the valve characteristics change mechanism is operating normally if the shaft position detection value changes by a predetermined amount or more when the drive amount changes across the determination reference value along with driving of the actuator, and performs abnormality determination to indicate that an abnormality is occurring in the valve characteristics change mechanism if the shaft position detection value changes by an amount less than the predetermined amount when the drive amount changes across the determination reference value.

4. The abnormality determination apparatus according to claim 1, wherein

the abnormality determiner performs abnormality determination to indicate that an abnormality is occurring in the valve characteristics change mechanism if the shaft position detection value changes when the drive amount does not change across the determination reference value along with driving of the actuator, and performs normality determination to indicate that the valve characteristics change mechanism is operating normally if the shaft position detection value does not change when the drive amount does not change across the determination reference value.

5. The abnormality determination apparatus according to claim 4, wherein

the abnormality determiner performs abnormality determination to indicate that an abnormality is occurring in the valve characteristics change mechanism if the shaft position detection value changes by a predetermined amount or more when the drive amount does not change across the determination reference value along with driving of the actuator, and performs normality determination to indicate that the valve characteristics change mechanism is operating normally if the shaft position detection value changes by an amount less than the predetermined amount when the drive amount does not change across the determination reference value.

6. The abnormality determination apparatus according to claim 1, wherein

the abnormality determiner performs normality determination to indicate that the valve characteristics change mechanism is operating normally if the drive amount at the time when the shaft position detection value changes along with driving of the actuator is equal to the determination reference value, and performs abnormality determination to indicate that an abnormality is occurring in the valve characteristics change mechanism if the drive amount at the time when the shaft position detection value changes is not equal to the determination reference value.

7. The abnormality determination apparatus according to claim 1, wherein

the abnormality determiner drives the control shaft in one direction to actually detect the drive amount at the time when the shaft position detection value changes, and stores the detected drive amount as the determination reference value.

8. The abnormality determination apparatus according to claim 7, wherein

the abnormality determiner displaces the control shaft in one direction to actually detect at least one said drive amount at the time when the shaft position detection value changes, stores the detected drive amount as the determination reference value, and calculates other determination reference values based on the determination reference value obtained from the actually detected drive amount.

9. The abnormality determination apparatus according to claim 7, wherein

after displacing the control shaft in one direction to store the determination reference value, the abnormality determiner performs a reference position learning process to correct the drive amount based on a drive amount detected when the control shaft is driven to and stopped at a mechanical limit movable position, and corrects the determination reference value based on a correction amount used in the reference position learning process.

10. An abnormality determination method that determines whether or not a valve characteristics change mechanism is operating normally, in an internal combustion engine that includes the valve characteristics change mechanism that changes a maximum lift amount and a lift duration of an engine valve continuously in correspondence with a position of a control shaft, an actuator that drives the control shaft, and a drive amount detector that detects a drive amount of the actuator, and that the valve characteristics change mechanism is configured to change the maximum lift amount and the lift duration of the engine valve by controlling the actuator such that the drive amount approaches a target drive amount, the abnormality determination method comprising:

outputting, as a shaft position detection value, a signal whose magnitude changes stepwise by a predetermined amount in correspondence with the position of the control shaft;

storing in advance, as a determination reference value, the drive amount at the time when a magnitude of the detected shaft position detection value changes;

performing normality determination to indicate that the valve characteristics change mechanism is operating normally when the drive amount detected when the shaft position detection value changes along with driving of the actuator and the determination reference value correspond to each other; and

performing abnormality determination to indicate that an abnormality is occurring in the valve characteristics change mechanism when the drive amount and the determination reference value do not correspond to each other.

11. The abnormality determination method according to claim 10, wherein

normality determination is performed to indicate that the valve characteristics change mechanism is operating normally if the shaft position detection value changes when the drive amount changes across the determination reference value along with driving of the actuator, and abnormality determination is performed to indicate that an abnormality is occurring in the valve characteristics change mechanism if the shaft position detection value does not change when the drive amount changes across the determination reference value.

12. The abnormality determination method according to claim 11, wherein

normality determination is performed to indicate that the valve characteristics change mechanism is operating normally if the shaft position detection value changes by a predetermined amount or more when the drive amount changes across the determination reference value along with driving of the actuator, and abnormality determination is performed to indicate that an abnormality is occurring in the valve characteristics change mechanism if the shaft position detection value changes by an amount less than the predetermined amount when the drive amount changes across the determination reference value.

13. The abnormality determination method according to claim 10, wherein

abnormality determination is performed to indicate that an abnormality is occurring in the valve characteristics change mechanism if the shaft position detection value changes when the drive amount does not change across the determination reference value along with driving of the actuator, and normality determination is performed to indicate that the valve characteristics change mechanism is operating normally if the shaft position detection value does not change when the drive amount does not change across the determination reference value.

14. The abnormality determination method according to claim 13, wherein

abnormality determination is performed to indicate that an abnormality is occurring in the valve characteristics change mechanism if the shaft position detection value changes by a predetermined amount or more when the drive amount does not change across the determination reference value along with driving of the actuator, and normality determination is performed to indicate that the valve characteristics change mechanism is operating normally if the shaft position detection value changes by an amount less than the predetermined amount when the drive amount does not change across the determination reference value.

15. The abnormality determination method according to claim 10, wherein

normality determination is performed to indicate that the valve characteristics change mechanism is operating normally if the drive amount at the time when the shaft position detection value changes along with driving of the actuator is equal to the determination reference value, and abnormality determination is performed to indicate that an abnormality is occurring in the valve characteristics change mechanism if the drive amount at the time when the shaft position detection value changes is not equal to the determination reference value.

16. The abnormality determination method according to claim 10, wherein

the control shaft is driven in one direction to actually detect the drive amount at the time when the shaft position detection value changes, and the detected drive amount is stored as the determination reference value.

17. The abnormality determination method according to claim 16, wherein

the control shaft is displaced in one direction to actually detect at least one said drive amount at the time when the shaft position detection value changes, stores the detected drive amount as the determination reference value, and other determination reference values are calculated based on the determination reference value obtained from the actually detected drive amount.

18. The abnormality determination method according to claim 16, wherein

after displacing the control shaft in one direction to store the determination reference value, a reference position learning process is performed to correct the drive amount based on a drive amount detected when the control shaft is driven to and stopped at a mechanical limit movable position, and the determination reference value is corrected based on a correction amount used in the reference position learning process.