Engine lubrication systems, lubrication fluid circulation systems, and methods for regulating fluid pressure

Patent metadata

Field	Value
Publication number	US-12188386-B2
Application number	US-202318497175-A
Country	US
Kind code	B2
Filing date	Oct 30, 2023
Priority date	May 4, 2021
Publication date	Jan 7, 2025
Grant date	Jan 7, 2025

Abstract

A lubrication system for an internal combustion engine includes a fluid flow control device at an outlet side of the pump that regulates pressure conditions at the outlet side of the pump upstream of the lubrication circuit in the engine. The fluid flow control device is located in a recirculation path, and opens in response to a fluid pressure at the outlet of the pump exceeding a first threshold to allow the fluid to pass from the outlet side of the pump back to an inlet side of the pump. The recirculation path includes a tuning device that maintains the fluid pressure at engine speeds above the first threshold. In response to engine speeds above a second threshold, the tuning device restricts fluid flow in the recirculation path so that the fluid pressure in the fluid flow path increases.

First claim

What is claimed is:

1. A lubrication system for an internal combustion engine, the system comprising:
a fluid flow path and a reservoir from which fluid is fed by a pump for circulation through the lubrication system via the fluid flow path;
a pressure regulator downstream of an outlet side of the pump, the pressure regulator configured to allow a flow of the fluid through a recirculation path in response to an engine speed exceeding a first threshold, the recirculation path connecting the outlet side of the pump to an inlet side of the pump; and
a tuning device in the recirculation path so that fluid flowing in the recirculation path from the outlet side of the pump to the inlet side of the pump flows through the tuning device, the tuning device being configured to:
not restrict flow of the fluid in the recirculation path passing through the tuning device in response to the engine speed exceeding the first threshold; and
restrict the flow of the fluid in the recirculation path passing through the tuning device in response to the engine speed exceeding a second threshold that is greater than the first threshold.

2. The system of claim 1 , wherein the fluid flow path is pressurized at a fluid pressure that is substantially constant between the first and second thresholds.

3. The system of claim 2 , wherein the fluid flow path is pressurized at a fluid pressure that progressively increases as the engine speed increases above the second threshold.

4. The system of claim 1 , wherein the tuning device is an orifice in the recirculation path between the outlet side of the pump and the pressure regulator.

5. The system of claim 1 , wherein the tuning device is an orifice in the recirculation path between the inlet side of the pump and the pressure regulator.

6. The system of claim 5 , wherein the orifice is located at an outlet of the pressure regulator.

7. The system of claim 5 , wherein the orifice is located at an inlet of the pump.

8. The system of claim 1 , wherein the tuning device is a spool valve in the pressure regulator.

9. The system of claim 1 , wherein the tuning device is a plunger stroke limiter in the pressure regulator.

10. The system of claim 1 , wherein the pressure regulator is closed during engine speeds less than the first threshold.

11. A method of regulating fluid pressure in an internal combustion engine, the method comprising:
circulating fluid through a lubrication system of the internal combustion engine via a fluid flow path, the lubrication system including a pump from which the fluid is fed into the fluid flow path and a recirculation path connecting an outlet side of the pump to an inlet side of the pump, the fluid in the recirculation path flowing through a fluid flow control device and a tuning device;
controlling, with the fluid flow control device, fluid flow through the recirculation path in response to an engine speed exceeding a first threshold, the fluid flow control device in the recirculation path downstream of the outlet side of the pump;
maintaining a substantially constant pressure in the fluid flow path with the fluid flow in the recirculation path in response to the engine speed exceeding the first threshold; and
restricting the fluid flow through the tuning device in the recirculation path in response to the engine speed exceeding a second threshold that is greater than the first threshold.

12. The method of claim 11 , wherein maintaining the substantially constant pressure in the fluid flow path includes maintaining the substantially constant pressure between the first and second thresholds.

13. The method of claim 12 , wherein restricting the fluid flow includes increasing a fluid pressure in the fluid flow path at engine speeds above the second threshold.

14. The method of claim 11 , wherein restricting the fluid flow includes restricting the fluid flow through an orifice located between the outlet side of the pump and the fluid flow control device.

15. The method of claim 11 , wherein restricting the fluid flow includes restricting the fluid flow through an orifice located between the inlet side of the pump and the fluid flow control device.

16. The method of claim 11 , wherein the tuning device is configured to only restrict the fluid flow in the recirculation path in response to the engine speed exceeding an engine overspeed condition that corresponds to the second threshold.

17. The method of claim 11 , wherein restricting the fluid flow in the recirculation path includes restricting the fluid flow with a pressure regulator that restricts the fluid flow in the recirculation path in response to the engine speed exceeding the second threshold.

18. The method of claim 11 , further comprising closing the fluid flow control device at engine speeds less than the first threshold to prevent fluid flow through the recirculation path.

19. A lubrication fluid circulation system for an internal combustion engine, the system comprising:
a pump for circulating fluid through the lubrication system via a fluid flow path;
a recirculation path having an inlet at a first end, an outlet at a second end opposite the first end, and a passage extending from the first end to the second end to allow the fluid to flow from the inlet to the outlet; and
a tuning device in the recirculation path so that fluid flowing in the recirculation path from the outlet side of the pump to the inlet side of the pump flows through the tuning device, the tuning device being configured to control an amount of the fluid flowing through the tuning device in the recirculation path and maintain a fluid pressure in the fluid flow path up to a predetermined speed of the engine, wherein the tuning device increases the fluid pressure in the fluid flow path by restricting the amount of the fluid passing through the tuning device that flows through the recirculation path in response to the predetermined speed of the engine being exceeded.

20. The lubrication fluid circulation system of claim 19 , wherein the recirculation path includes a pressure regulator that prevents fluid flow through the recirculation path at engine speeds below a first threshold, the pressure regulator being configured to open at engine speeds above the first threshold to permit fluid flow through the recirculation path.

Assignees

• Cummins Inc

Inventors

• Welch Nicholas James
• Flessner Matthew D

Classifications

• F01M2250/60

  Operating parameters · CPC title

• F01M11/02

  Arrangements of lubricant conduits · CPC title

• F01M1/02 Primary

  using lubricating pumps (pumps in general F04; lubricating pumps per se F16N) · CPC title

• F16N2270/60

  Pressure · CPC title

• F16N2250/16

  Number of revolutions, RPM · CPC title