Engine variable valve lift system having integrated hydraulic fluid retention

Patent metadata

Field	Value
Publication number	US-9631526-B2
Application number	US-201514848437-A
Country	US
Kind code	B2
Filing date	Sep 9, 2015
Priority date	Sep 17, 2014
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

An electro-hydraulic variable valve lift system includes a medium pressure chamber, a high pressure circuit, a valve, a pump and an actuator. The chamber is formed in a cylinder head assembly and is in fluid communication with a hydraulic fluid source. The high pressure circuit is positioned in the cylinder head assembly and is in selective fluid communication with the chamber. The valve is in fluid communication with the chamber and the high pressure circuit, and the pump is configured to pump hydraulic fluid in the high pressure circuit. The actuator is in fluid communication with the pump, control valve and high pressure circuit, and is in engagement with an intake valve. The chamber and the actuator are each positioned in the cylinder head assembly at a location above the valve such that during an engine shutdown event, hydraulic fluid is retained in the chamber and the valve.

First claim

What is claimed is:

1. An electro-hydraulic actuator system for a variable valve lift system of an engine, the electro-hydraulic actuator system comprising:
a medium pressure chamber formed in a cylinder head assembly and adapted to be in fluid communication with a source of hydraulic fluid;
a high pressure fluid circuit positioned in the cylinder head assembly and in selective fluid communication with and receiving hydraulic fluid from the medium pressure chamber;
a control valve positioned in the cylinder head assembly and in fluid communication with the medium pressure chamber and the high pressure fluid circuit;
a pump configured to pump hydraulic fluid in the high pressure fluid circuit; and
an actuator in fluid communication with the pump, control valve and high pressure fluid circuit, the actuator in engagement with an intake valve of the engine;
wherein the high pressure fluid circuit includes a first fluid passage fluidly coupled between the pump and the control valve, and a second fluid passage fluidly coupled between the control valve and the actuator, the second fluid passage having a valve end coupled to the valve and an opposite actuator end coupled to the actuator, the second fluid passage inclined such that the hydraulic fluid flows upwardly in the second fluid passage from the valve end toward the actuator end when the engine is in a level operating position;
wherein the control valve is configured to be controlled to selectively block fluid communication between the high pressure fluid circuit and the medium pressure chamber thereby providing for the hydraulic fluid pumped by the pump to displace the actuator to open the intake valve; and
wherein the medium pressure chamber and the actuator are each positioned in the cylinder head assembly at a location higher than the control valve such that during an engine shutdown event, hydraulic fluid is retained in the medium pressure chamber and the control valve.

2. The actuator system of claim 1 , wherein the medium pressure chamber includes an upper end and an opposed lower end fluidly coupled to the control valve such that fluid flows from the medium pressure chamber downwardly to the control valve when the engine is in a level operating position.

3. The actuator system of claim 2 , wherein the upper end of the medium pressure chamber and the actuator end of the second fluid passage are both positioned higher in the cylinder head assembly than the control valve, thereby retaining fluid in at least a portion of the medium pressure chamber, the control valve and the second fluid passage during extended periods of engine non-use.

4. The actuator system of claim 3 , wherein the actuator system is configured to retain fluid in the second fluid passage such that fluid is retained in all of the second fluid passage from the valve end to the actuator end.

5. The actuator system of claim 3 , wherein the medium pressure chamber includes a vertically extending stacked-pipe portion extending from an upper portion of the medium pressure chamber defining the upper end to and defining the lower end of the medium pressure chamber, the vertically extending stacked-pipe portion retaining fluid during the extended periods of non-use.

6. The actuator system of claim 5 , wherein the stacked-pipe portion extends vertically from the control valve to a position above the actuator end of the second fluid passage and to the upper portion of the medium pressure chamber.

7. The actuator system of claim 1 , wherein the pump is in engagement with a camshaft of the cylinder head assembly and is actuated by the same.

8. The actuator system of claim 1 , wherein the medium pressure chamber includes an accumulator.

9. The actuator system of claim 1 , wherein the actuator is a brake guide actuator operably associated with an intake valve.

10. The actuator system of claim 1 , wherein the first fluid passage is separate from the second fluid passage.

11. An electro-hydraulic actuator system for a variable valve lift system of an engine, the electro-hydraulic actuator system comprising:
a housing;
a pump configured to pump hydraulic fluid;
a hydraulic brake guide actuator configured to engage an intake valve of the engine;
a control valve configured to selectively supply the hydraulic fluid to the hydraulic brake guide actuator;
a medium pressure chamber formed in the housing and configured to receive a supply of the hydraulic fluid;
a first fluid passage formed in the housing and fluidly coupled between the pump and the control valve;
a second fluid passage formed in the housing and fluidly coupled between the control valve and the hydraulic brake guide actuator, the second fluid passage being separate from the first fluid passage and inclined such that hydraulic fluid must travel upwardly from the control valve to the hydraulic brake guide actuator; and
a third fluid passage formed in the housing and fluidly coupled between the medium pressure chamber and the control valve;
wherein a lowest point of the control valve is disposed below a lowest point of the medium pressure chamber and a lowest point of the second fluid passage; and
wherein a highest point and the lowest point of the second fluid passage are disposed above the lowest point of the medium pressure chamber.

Assignees

• Nowak Peter E
• Fca Us Llc

Inventors

• Nowak Peter E

Classifications

• F01L9/023

  Mechanical Engineering · mapped topic

• F01L9/021

  Mechanical Engineering · mapped topic

• F01L9/02

  Mechanical Engineering · mapped topic

• F01L9/025 Primary

  Mechanical Engineering · mapped topic

• F01L9/14 Primary

  the volume of the chamber being variable, e.g. for varying the lift or the timing of a valve · CPC title