Intake valve closure control for dual-fuel engines

Patent metadata

Field	Value
Publication number	US-9279350-B2
Application number	US-201414287909-A
Country	US
Kind code	B2
Filing date	May 27, 2014
Priority date	May 27, 2014
Publication date	Mar 8, 2016
Grant date	Mar 8, 2016

Abstract

A system and a method for actuating intake valves of an internal combustion engine. The system includes a hydraulic circuit including a master cylinder, a control valve, an accumulator, a first one-way valve and a slave cylinder. The slave cylinder accommodates a slave piston, which is coupled to the intake valves. The control valve is disposed upstream of the accumulator for controlling flow from the hydraulic circuit to the accumulator. The first one-way valve is disposed downstream of the accumulator for permitting flow from the accumulator to the hydraulic circuit and for preventing flow from the hydraulic circuit to the accumulator without first passing through the control valve. The control valve has an open position that provides communication between the hydraulic circuit and the accumulator for a Miller cycle or Miller-like cycle operation. The control valve also has a closed position that prevents communication between the hydraulic circuit and the accumulator during Otto cycle operation.

First claim

What is claimed:

1. An actuation system for a valve of an internal combustion engine, the system comprising:
a hydraulic circuit including
a master cylinder and a slave cylinder, the slave cylinder accommodating a slave piston,
a first passageway in fluid communication with the master cylinder and the slave cylinder,
a control valve configured to direct fluid flow between the master cylinder and an accumulator by way of a second passageway in fluid communication with the first passageway and the control valve, and a third passageway, isolated from the first passageway and in fluid communication with the control valve and the accumulator,
a first one way valve positioned in a fourth passageway, the fourth passageway in fluid communication with the accumulator and the first passageway and configured to permit fluid flow only in a direction from the accumulator to the first passageway;

wherein the slave piston is coupled to an intake valve and
wherein the control valve is configured to have an open position providing fluid communication between the master cylinder and the accumulator and a closed position preventing fluid communication between the master cylinder and the accumulator.

2. The actuation system of claim 1 wherein the control valve is a normally closed control valve.

3. The actuation system of claim 1 wherein the control valve is a normally closed control valve that is linked to a controller, the controller configured to send signals to move the control valve between the open and closed positions.

4. The actuation system of claim 1 wherein the engine operates as an Otto cycle engine having a first compression ratio when the control valve is closed.

5. The actuation system of claim 4 wherein the engine operates with a second compression ratio that is less than the first compression ratio when the control valve is open.

6. The actuation system of claim 1 wherein the first one-way valve is a check valve.

7. The actuation system of claim 1 wherein the hydraulic circuit further includes a fluid supply and a second one-way valve positioned in a fifth passageway, the second one way valve being configured to permit fluid flow only in a direction from the fluid supply to the first passageway.

8. The actuation system of claim 1 wherein the slave cylinder accommodates a snub plate that attenuates flow from the slave cylinder to the hydraulic circuit.

9. The actuation system of claim 1 wherein when the control valve is in the open position, fluid flows from the master cylinder to the slave cylinder thereby enabling the slave piston to actuate the intake valve.

10. The actuation system of claim 1 further including a hydraulic lash adjuster disposed between the slave piston and the intake valve.

11. The actuation system of claim 1 wherein the slave piston is coupled to a plurality of intake valves.

12. The actuation system of claim 1 wherein the accumulator includes an accumulator cylinder having a closed distal end and an open end that is in fluid communication with the first passageway and the fourth passageway, the accumulator further including an accumulator piston slidably received in the accumulator cylinder and a biasing element disposed between the piston and the closed end of the accumulator cylinder for biasing the accumulator piston towards the open end,
the accumulator piston including a first bleed orifice that provides communication between the open end and the closed end of the accumulator cylinder, the closed end of the accumulator cylinder including a second bleed orifice that provides communication between the closed end of the accumulator cylinder and a reservoir.

13. An internal combustion engine, comprising:
a hydraulic circuit including
a master cylinder, the master cylinder accommodating a master piston, and a slave cylinder, the slave cylinder accommodating a slave piston, wherein the master piston engages a rotating cam synchronized with the engine and wherein the slave piston is coupled to an intake valve,
a first passageway in fluid communication with the master cylinder and the slave cylinder,
a control valve configured to direct fluid flow between the master cylinder and an accumulator by way of a second passageway in fluid communication with the first passageway and the control valve, and a third passageway, isolated from the first passageway and in fluid communication with the control valve and the accumulator,
a first one-way valve positioned in a fourth passageway, the fourth passageway in fluid communication with the accumulator and the first passageway, the first one way valve configured to permit fluid flow only in a direction from the accumulator to the first passageway;

wherein the control valve is configured to have an open position providing fluid communication between the master cylinder and the accumulator and a closed position preventing fluid communication between the master cylinder and the accumulator; and
wherein the engine operates as an Otto cycle engine with a first compression ratio when the control valve is closed and wherein the engine operates with a second effective compression ratio that is less than the first compression ratio when the control valve is open.

14. The engine of claim 13 wherein the control valve is a normally closed control valve.

15. The engine of claim 13 wherein the control valve is a normally closed control valve that is linked to a controller, the controller programmed to send signals to move the control valve between the open and closed positions.

16. The engine of claim 13 wherein the first one-way valve is a check valve.

17. The engine of claim 13 wherein the hydraulic circuit further includes a fluid supply and a second one-way valve positioned in a fifth passageway, the second one way valve being configured to permit fluid flow only in a direction from the fluid supply to the first passageway.

18. The engine of claim 17 wherein the second one-way valve is a check valve.

19. The engine of claim 13 wherein the slave cylinder accommodates a snub plate that attenuates flow from the slave cylinder to the first passageway.

20. A method for changing the compression ratio of a dual-fuel internal combustion engine that includes a valve actuator having a hydraulic circuit including a master cylinder and a slave cylinder, the slave cylinder accommodating a slave piston, a first passageway in fluid communication with the master cylinder and the slave cylinder, a control valve configured to direct fluid flow between the master cylinder and an accumulator by way of a second passageway in fluid communication with the first passageway and the control valve, and a third passageway, isolated from the first passageway and in fluid communication with the control valve and the accumulator, a first one way valve positioned in a fourth passageway, the fourth passageway in fluid communication with the accumulator and the first passageway and configured to permit fluid flow only in a direction from the accumulator to the first passageway; wherein the slave piston is coupled to an intake valve and wherein the control valve is configured to have an open position providing fluid communication between the master cylinder and the accumulator and a closed position preventing fluid communication between the master cylinder and the accumulator, the method comprising:
closing the control valve to prevent communication between the first passageway and the accumulator and to operate the engine with a first compression ratio; and
opening the control va

Assignees

• Caterpillar Inc

Inventors

• Yeager Kendall D
• Schreader Kevin J
• Yacoub Victor I
• Langewisch Edwin Henry

Classifications

• F01L1/34

  characterised by the provision of means for changing the timing of the valves without changing the duration of opening {and without affecting the magnitude of the valve lift} · CPC title

• F01L1/24 Primary

  by fluid means, e.g. hydraulically · CPC title

• F01L9/02 Primary

  Mechanical Engineering · mapped topic

• F01L9/10 Primary

  by fluid means, e.g. hydraulic · CPC title

• Y02T10/12

  Improving ICE efficiencies · CPC title