Engine valve actuation system and method

• US 7,063,055 B2
• Filed: 10/22/2004
• Issued: 06/20/2006
• Est. Priority Date: 05/14/2002
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Pierpont, David Andrew, Leman, Scott Alan, Bloms, Jason Kenneth, Faletti, James J., Holtman, Richard Herman
• Primary Examiner(s): Denion, Thomas
• Assistant Examiner(s): Chang, Ching
• Application Number:
  US10/969,957
• Publication Number:
  US 20050051119A1
• Time in Patent Office: 606 Days
• Field of Search: 123 9011- 9018, 123320-322, 123/90.39, 123/90.44, 123/347, 123/348, 123/350, 123/406.12, 123/406.13
• US Class Current: 123/90.12
• CPC Class Codes: F01L 1/267 with means for varying the timing or the lift of the valves
• CPC Class Codes: F01L 13/06 for braking
• CPC Class Codes: F01L 2001/34446 Fluid accumulators for the feeding circuit
• CPC Class Codes: F01L 9/11 in which the action of a cam is being transmitted to a valve by a liquid column
• CPC Class Codes: F02B 2275/32 Miller cycle
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

An engine valve actuation system is provided. The system includes an engine valve moveable between a closed position and an open position. A spring is operatively connected to the engine valve to bias the engine valve towards the closed position. An actuator is operatively connected to the engine valve and is operable to selectively engage the engine valve to prevent the engine valve from returning to the closed position and to release the engine valve to allow the engine valve to return to the closed position. A sensor is configured to provide information related to the operation of the actuator. A controller is configured to transmit a signal to the actuator to engage the engine valve to prevent the engine valve from returning to the closed position and to release the engine valve to the allow the engine valve to return to the closed position. The controller is further configured to receive a signal from said sensor and to identify when the actuator fails to engage the engine valve in response to the transmitted signal or when the actuator fails to release the engine valve.

Claims

1. An engine valve actuation system, comprising:

an engine valve moveable between a closed position and an open position;

a cam configured to move the engine valve between the closed position and the open position;

a spring operatively connected to the engine valve to bias the engine valve towards the closed position;

an actuator operatively connected to the engine valve, the actuator operable to selectively engage the engine valve to prevent the engine valve from returning to the closed position and to release the engine valve to allow the engine valve to return to the closed position;

a sensor configured to provide information related to the operation of the actuator; and

a controller configured to transmit a signal to the actuator to engage the engine valve to prevent the engine valve from returning to the closed position and to release the engine valve to allow the engine valve to return to the closed position, the controller further configured to receive a signal from said sensor and to identify when the actuator fails to engage the engine valve in response to the transmitted signal or when the actuator fails to release the engine valve.

2. The system of claim 1, wherein the sensor provides information related to at least one of a current applied to a directional control valve, a voltage applied to the directional control valve, the resistance of the signal transmitted to the directional control valve, the inductance of the signal transmitted to the directional control valve, the continuity of the signal transmitted to the directional control valve, an engine speed, an engine torque, a motion of the actuator, a pressure in a cylinder, an actuator fluid pressure, an intake air pressure, an intake air flow rate, and a turbocharger speed.

3. The system of claim 1, wherein the information relates to a operating condition of the engine.

4. The system of claim 1, wherein the information relates to a status of the actuator.

5. The system of claim 1, further including:

a source of hydraulic fluid in fluid communication with the actuator; and

a directional control valve disposed between the source of hydraulic fluid and the actuator and moveable between an open position to allow a flow of hydraulic fluid from the source of hydraulic fluid to the actuator and a closed position to prevent the flow of fluid between the source of hydraulic fluid and the actuator.

6. The system of claim 5, wherein the actuator engages the engine valve to prevent the engine valve from returning to the closed position in response to the controller moving the directional control valve to the closed position.

7. The system of claim 6, wherein the sensor is disposed in operative connection with the source of hydraulic fluid.

8. A method of controlling an engine valve, comprising:

operating a cam assembly to move an engine valve between a closed position and an open position;

transmitting a signal to engage an actuator with the engine valve when the engine valve is at least partially open to prevent the engine valve from returning to the closed position and to release the engine valve to allow the engine valve to return to the closed position; and

identifying when the actuator fails to engage the engine valve in response to the transmitted signal or when the actuator fails to release the engine valve.

9. The method of claim 8, wherein the engine valve is an intake valve and the actuator prevents the intake valve from closing until a piston completes at least a portion of a compression stroke.

10. The method of claim 8, wherein the signal is transmitted to a directional control valve that controls a flow of fluid to and from the actuator.

11. The method of claim 10, wherein the signal is a current and the current is monitored to identify an inflection in the current.

12. The method of claim 10, further including closing the directional control valve to engage the actuator with the engine valve and opening the directional control valve to allow the engine valve to close.

13. The method of claim 8, further including sensing at least one operating condition indicative of the condition where the engine valve fails to respond to the transmitted signal.

14. The method of claim 13, further including sensing at least one of an engine speed, an engine torque, a motion of the actuator, a pressure in a cylinder, an actuator fluid pressure, an intake air pressure, an intake air flow rate, and a turbocharger speed.

15. The method of claim 13, further including terminating fueling to a cylinder when the actuator fails to engage or release the engine valve.

16. An engine, comprising,

an engine block defining at least one cylinder;

at least one piston slidably disposed within the at least one cylinder;

at least one intake valve operatively associated with the at least one cylinder;

a cam assembly operatively connected to the at least one intake valve to move the intake valve between a closed position and an open position;

an actuator operatively connected to the engine valve, the actuator configured to selectively engage the engine valve to prevent the engine valve from returning to the closed position and to release the engine valve to allow the engine valve to return to the closed position; and

a controller configured to transmit a signal to the actuator to engage the engine valve to prevent the engine valve from returning to the closed position and to release the engine valve to the allow the engine valve to return to the closed position, the controller further configured to identify when the actuator fails to engage the engine valve in response to the transmitted signal or when the actuator fails to release the engine valve.

17. The engine of claim 16, further including at least one sensor configured to sense at least one of an engine speed, a motion of the actuator, a pressure in a cylinder, an actuator fluid pressure, an intake air pressure, an intake air flow rate, and a turbocharger speed.

18. The engine of claim 17, further including:

a source of hydraulic fluid in fluid communication with the fluid actuator; and

a directional control valve disposed between the source of hydraulic fluid and the actuator and moveable between an open position to allow a flow of hydraulic fluid from the source of hydraulic fluid to the actuator and a closed position to prevent the flow of fluid between the source of hydraulic fluid and the actuator.

19. The engine of claim 18, wherein the directional control valve is moveable between an open position to allow a flow of hydraulic fluid to or from the actuator and a closed position to prevent a flow of fluid to or from the actuator.

20. The engine of claim 19, wherein the actuator engages the engine valve to prevent the engine valve from returning to the closed position in response to the controller moving the directional control valve to the closed position.

21. The engine of claim 16, further including a turbocharger configured to provide charged air to the at least one cylinder.

22. The engine of claim 16, further including a cooler configured to reduce the temperature of the charged air provided by the turbocharger.

23. A method of controlling an engine valve, comprising:

operating a cam assembly to move an engine valve between a closed position and an open position;

transmitting a signal to engage an actuator with the engine valve to alter movement of the valve with respect to said cam assembly;

monitoring a parameter that is affected by the operation of the actuator; and

generating a warning signal when the monitored parameter is indicative of a failure of the actuator to engage the engine valve.

24. The method of claim 23, further including monitoring an operating condition of the engine.

25. The method of claim 23, further including monitoring a status of the actuator.

26. The method of claim 23, wherein the monitored parameter is at least one of an engine speed, an engine torque, a motion of the actuator, a pressure in a cylinder, an actuator fluid pressure, an intake air pressure, an intake air flow rate, and a turbocharger speed.