Engine valve actuation system

• US 6,907,851 B2
• Filed: 12/04/2002
• Issued: 06/21/2005
• Est. Priority Date: 05/14/2002
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Wu, Di, Milam, David M., Handly, Douglas E., Cornell, Sean O., Robel, Wade J., Leman, Scott A., Barnes, Travis E., Bruce, Judson R.
• Primary Examiner(s): Denion, Thomas
• Assistant Examiner(s): Riddle, Kyle M.
• Application Number:
  US10/309,801
• Publication Number:
  US 20030221644A1
• Time in Patent Office: 930 Days
• Field of Search: 123/90.12, 123/90.13, 123/90.15, 123/90.16, 123/90.31, 123/198.F, 123/90.27, 137/14
• US Class Current: 123/90.12
• CPC Class Codes: F01L 1/146 Push-rods
• CPC Class Codes: F01L 1/26 characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder with coaxial valves F01L1/28
• CPC Class Codes: F01L 13/0015 for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
• CPC Class Codes: F01L 13/06 for braking
• CPC Class Codes: F01L 2001/34446 Fluid accumulators for the feeding circuit
• CPC Class Codes: F01L 2013/0089 with means for delaying valve closing
• CPC Class Codes: F01L 2800/00 Methods of operation using a variable valve timing mechanism
• CPC Class Codes: F01L 9/10 by fluid means, e.g. hydraulic
• CPC Class Codes: F01L 9/12 with a liquid chamber between a piston actuated by a cam and a piston acting on a valve stem
• 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 engine valve actuation system includes an intake valve that is moveable between a first position to prevent a flow of fluid and a second position to allow a flow of fluid. A cam assembly is configured to move the intake valve between the first position and the second position. A fluid actuator is configured to selectively prevent the intake valve from moving to the first position. A source of fluid is in fluid communication with the fluid actuator. A directional control valve is configured to control a flow of fluid between the source of fluid and the fluid actuator. A check valve is disposed between the directional control valve and the source of fluid, only allowing fluid flow from the fluid source to the directional control valve. A bleed orifice may be disposed between the directional control valve and the source of fluid, in parallel with the check valve.

Claims

1. An engine valve actuation system comprising:

an intake valve moveable between a first position to prevent a flow of fluid and a second position to allow a flow of fluid;

a cam assembly connected to move said intake valve between said first position and said second position;

a fluid actuator configured to selectively prevent said intake valve from moving to said first position;

a source of fluid in fluid communication with said fluid actuator;

a directional control valve configured to control a flow of fluid between said source of fluid and said fluid actuator;

a fluid line check valve disposed between said source of fluid and said directional control valve and only allowing said flow of fluid therethrough to travel from said source of fluid to said directional control valve; and

a bleed orifice, wherein said bleed orifice and said fluid line check valve are disposed in parallel between said source of fluid and said directional control valve.

2. The engine valve actuation system of claim 1 further including:

a main gallery positioned between said source of fluid and said check valve;

a fluid rail positioned between said fluid line check valve and said directional control valve said fluid rail having a first end and a second end, wherein said first end is in fluid communication with said fluid line check valve; and

a fluid line disposed between said main gallery and said fluid rail.

3. The engine valve actuation system of claim 2 wherein said fluid line check valve is disposed in said fluid line.

4. The engine valve actuation system of claim 2 wherein said fluid line check valve is positioned closer to said main gallery than said fluid rail.

5. The engine valve actuation system of claim 2 wherein said fluid line check valve is integral with said main gallery.

6. The engine valve actuation system of claim 2 wherein said fluid line check valve is integral with said fluid line.

7. The engine valve actuation system of claim 2 further including a control valve in fluid communication with said second end of said fluid rail and being moveable between a first position to prevent said flow of fluid from said fluid rail and a second position to allow said flow of fluid from said fluid rail.

8. The engine valve actuation system of claim 7 further including a controller configured to move said control valve between said first position and said second position.

9. The engine valve actuation system of claim 7 further including a tank in fluid communication with said source of fluid and said control valve.

10. The engine valve actuation system of claim 2 further including a restrictive orifice disposed between said fluid line check valve and said first end of said fluid rail.

11. A method of controlling fluid pressure in a fluid rail comprising:

delivering fluid to a fluid rail from a fluid source;

moving a cam to actuate an engine valve;

delivering said fluid from said fluid rail through a control valve to an actuator chamber of a fluid actuator;

moving an actuator rod of said fluid actuator from a first position to a second position in response to said delivering said fluid from said fluid rail to said actuator chamber;

reversing fluid flow from said actuator chamber back through said control valve to said fluid rail in response to said actuator rod moving towards said first position; and

limiting a fluid flow from said fluid rail to said fluid source in response to said delivering fluid from said actuator chamber back to said fluid rail step.

12. The method of claim 11 wherein said limiting step further includes:

preventing said fluid flow from said fluid rail to said fluid source in response to said delivering fluid from said actuator chamber back to said fluid rail.

13. The method of claim 11 further including:

bleeding fluid through a bleed orifice from said fluid rail when said fluid rail is not in use.

14. The method of claim 11 further including:

increasing an effective volume of said fluid rail.