OIL PRESSURE CONTROL IN AN ENGINE

• US 20100284823A1
• Filed: 05/05/2009
• Published: 11/11/2010
• Est. Priority Date: 05/05/2009
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Pryor, Bryan K., Albertson, William C., Mc Donald, Mike M., Reynolds, Michael G.
• Granted Patent: US 8,245,684 B2
• Time in Patent Office: Days
• US Class Current: 417/13
• CPC Class Codes: F01M 1/16 Controlling lubricant pressure or quantity rendering machines or engines inoperative or idling on lubricant pressure failure F01M1/22
• CPC Class Codes: F01M 5/025 by prelubricating, e.g. using an accumulator

Abstract

An engine having a fluid lubrication and control system is provided. The engine also includes a pump configured to maintain fluid pressure in the lubrication and control system when the engine is running. The engine additionally includes an accumulator in fluid communication with the lubrication and control system. The accumulator is configured to accumulate and retain fluid when the engine is running, and to discharge the fluid when the engine is not running in order to maintain fluid pressure in the lubrication and control system. A method for controlling oil pressure in the engine is also provided.

Claims

1. An internal combustion engine comprising:

a fluid lubrication and control system;

a pump configured to maintain fluid pressure in the lubrication and control system when the engine is running; and

an accumulator in fluid communication with the lubrication and control system, the accumulator configured to accumulate and retain fluid when the engine is running, and to discharge the fluid when the engine is not running, thereby maintaining fluid pressure in the lubrication and control system.

2. The engine of claim 1, wherein the lubrication and control system includes:

a check-valve configured to allow filling of the accumulator with fluid when the engine is running, and retain the fluid inside the accumulator when the engine is not running; and

a first control valve configured to selectively close to retain fluid in the accumulator when the engine is running and open to discharge the fluid from the accumulator when the engine is not running.

3. The engine of claim 2, further comprising an electronic controller arranged relative to the engine and configured to selectively open and close the first control valve.

4. The engine of claim 3, further comprising a second control valve configured to selectively open to permit filling of the accumulator and close to prevent filling of the accumulator, wherein the electronic controller is configured to selectively open and close the second control valve.

5. The engine of claim 1, further comprising a filter in fluid communication with the lubrication and control system and with the pump, wherein the lubrication and control system includes a check-valve configured to prevent fluid retained in the accumulator from flowing back into the filter and the pump when the engine is not running.

6. The engine of claim 1, wherein the fluid lubrication and control system includes a camshaft phaser operable by fluid pressure.

7. The engine of claim 6, wherein the accumulator is configured to maintain fluid pressure to the camshaft phaser when the engine is not running.

8. The engine of claim 1, wherein the accumulator is configured to discharge the fluid to the fluid lubrication and control system when the engine is being restarted.

9. A method for controlling oil pressure in a vehicle powertrain having an internal combustion engine with a start-stop function, the engine including a fluid lubrication and control system, an oil filter, and an oil pump driven by the engine to maintain fluid pressure to the lubrication and control system when the engine is running, the method comprising:

accumulating engine oil via an accumulator when the engine is running;

retaining the oil in the accumulator when the engine is shut-off,

determining whether the engine is shut-off due to a start-stop event;

determining whether engine shut-off time is greater than a minimum shut-off time;

determining a temperature of the engine oil if the engine shut-off time is greater than the minimum shut-off time;

determining an accumulator discharge time based on the determined temperature of the engine oil; and

discharging the engine oil via the accumulator for the determined discharge time when the engine is not running to maintain engine oil pressure.

10. The method for controlling oil pressure of claim 9, wherein the fluid lubrication and control system includes a camshaft phaser operable by fluid pressure.

11. The method for controlling oil pressure of claim 9, further comprising limiting a rate of oil accumulation via an orifice.

12. The method for controlling oil pressure of claim 9, further comprising preventing oil from flowing back into the oil pump and into the oil filter when the engine is not running and the accumulator is discharging.

13. The method for controlling oil pressure of claim 9, wherein said determining whether the engine is shut-off due to a start-stop event, said determining whether engine shut-off time is greater than a minimum shut-off time, said determining accumulator discharge time based on the determined temperature of engine oil, and said discharging engine oil for the determined discharge time are accomplished via a controller.

14. The method for controlling oil pressure of claim 13, wherein said determining accumulator discharge time based on the determined temperature of engine oil is accomplished using a look up table programmed into the controller.

15. A fluid lubrication and control system for an internal combustion engine having a camshaft phaser operable by fluid pressure, the system comprising:

a pump configured to maintain fluid pressure in the system when the engine is running; and

an accumulator configured to accumulate and retain fluid when the engine is running, and to discharge the fluid when the engine is restarted after being shut-off, wherein the accumulator is in fluid communication with the camshaft phaser such that fluid pressure to the camshaft phaser is maintained by the discharged fluid.

16. The fluid lubrication and control system of claim 15, wherein the accumulator includes:

a check-valve configured to fill the accumulator with fluid when the engine is running, and retain the fluid inside the accumulator when the engine is shut-off, and

a first control valve configured to selectively close to retain fluid in the accumulator when the engine is running and open to discharge the fluid from the accumulator when the engine is restarted.

17. The fluid lubrication and control system of claim 16, further comprising an electronic controller configured to selectively open and close the first control valve.

19. The fluid lubrication and control system of claim 17, further comprising a second control valve configured to selectively open to permit filling of the accumulator and close to prevent filling of the accumulator, wherein the electronic controller is configured to selectively open and close the second control valve.

20. The fluid lubrication and control system of claim 15, further comprising a filter in fluid communication with the pump, and a check-valve configured to prevent fluid retained in the accumulator from flowing back into the filter and the pump when the engine is shut-off.