Engine valve actuation system

• US 7,258,088 B2
• Filed: 12/12/2005
• Issued: 08/21/2007
• Est. Priority Date: 05/14/2002
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Cornell, Sean O., Leman, Scott Alan
• Primary Examiner(s): Chang; Ching
• Application Number:
  US11/298,517
• Publication Number:
  US 20060086329A1
• Time in Patent Office: 617 Days
• Field of Search: 123/90.12, 123/90.13, 123/90.39, 123/90.44
• 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 13/065 Compression release engine retarders of the "Jacobs Manufacturing" type
• 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 2305/00 Valve arrangements comprising rollers
• 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: F02D 13/0269 Controlling the valves to perform a Miller-Atkinson cycle
• CPC Class Codes: F02D 15/04 by alteration of volume of compression space without changing piston stroke
• 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 fluid passageway connects the directional control valve with the fluid actuator. An accumulator is in fluid communication with the fluid passageway. A restricted orifice is disposed between the accumulator and the fluid passageway to restrict a flow of fluid between the accumulator and the fluid passageway.

Claims

1. A fluid actuator for selectively preventing an engine valve from closing, comprising:

a housing having an inlet, a snubbing valve chamber, an actuator chamber, a first fluid passageway connecting the inlet with the snubbing valve chamber, a second fluid passageway connecting the inlet with the snubbing valve chamber, and a third fluid passageway connecting the snubbing valve chamber with the actuator chamber;

a snubbing valve disposed in the snubbing valve chamber and adapted to control a flow rate of fluid through the third fluid passageway;

a check valve disposed in the first fluid passageway and adapted to allow a flow of fluid from the inlet through the first fluid passageway to the snubbing valve chamber and to prevent a flow of fluid from the snubbing valve chamber through the first fluid passageway to the inlet;

an accumulator in fluid communication with the first and second fluid passageways;

a restricted orifice disposed between the first and second fluid passageways and the accumulator; and

a piston having an actuator rod and being disposed in the actuator chamber, the piston adapted to move the actuator rod into an engine valve actuation position in response to an introduction of fluid to the actuator chamber.

2. The actuator of claim 1, wherein the inlet includes a first opening for the first fluid passageway and a second opening for the second fluid passageway.

3. The actuator of claim 1, further including a spring acting on the piston to move the actuator rod away from the engine valve actuation position.

4. The actuator of claim 1, wherein the accumulator includes a chamber, a piston moveable between a first position where the volume of the chamber is minimized and a second position where the volume of the chamber is maximized, and a spring acting on the piston to bias the piston towards the first position.

5. The actuator of claim 1, wherein the check valve includes a seat, a poppet, and a spring acting on the poppet to engage the poppet with the seat.

6. The actuator of claim 1, further including a piston stop adapted to stop the piston when the actuator rod reaches the engine valve actuation position.