Lubricating system for internal combustion engine

• US 20020003063A1
• Filed: 05/09/2001
• Published: 01/10/2002
• Est. Priority Date: 05/09/2000
• Status: Active Grant

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Yoshida, Yoshihiro, Yasuda, Kazuhiro, Tawara, Hideyuki, Ito, Katsuhiko
• Granted Patent: US 6,598,705 B2
• Time in Patent Office: Days
• US Class Current: 184/6.5
• CPC Class Codes: F01M 1/12 Closed-circuit lubricating systems not provided for in groups F01M1/02 - F01M1/10
• 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 2001/123 using two or more pumps
• CPC Class Codes: F01M 2001/126 Dry-sumps
• CPC Class Codes: Y10T 137/2605 Pressure responsive

Abstract

An oil passage extending from an oil pump to a discharge port in an internal combustion engine is, at its halfway point, branched into at least two oil passages, for example, a first oil passage and a second oil passage. One of the at least two branched oil passages, for example, the second oil passage is provided with a restricting portion configured as a first orifice for restricting a flow amount of oil by reducing a diameter of the first orifice. A bypass valve is provided which acts, when a hydraulic pressure in the second oil passage exceeds a specific value, to bypass the first orifice so as to increase the flow rate of oil. It is possible to increase the hydraulic pressure at the time of low speed rotation up to a necessary pressure only by providing the restricting portion, without enhancing the performance of the oil pump. Accordingly, it is possible to suppress the increase in weight and cost of the lubricating system as compared with the prior art lubricating system in which the performance of the oil pump is enhanced, and since it is not required to increase the rotational speed of the oil pump, it is possible to prevent the loss in output of the internal combustion engine due to the increased friction of the oil pump. Further, it is possible to prevent an excessive increase in pressure of the oil passage by the effect of the bypass valve.

Claims

1. A lubricating system for an internal combustion engine, comprising:

an oil passage extending from an oil pump to a discharge port in an internal combustion engine is, at its halfway point, branched into at least two oil passages; and

one of said at least two branched oil passages is provided with a restricting portion for restricting a flow amount of oil by reducing a diameter of said restricting portion, and a bypass valve which acts, when a hydraulic pressure in said oil passage exceeds a specific value to bypass said restricting portion so as to increase the flow rate of oil.

2. The lubricating system for an internal combustion engine according to claim 1, wherein said one of said at least two branched oil passages includes a first section and a second section, said second section including said bypass valve being movably mounted therein for selectively permitting oil to flow into said second section when the hydraulic pressure in the oil passage exceeds a specified value.

3. The lubricating system for an internal combustion engine according to claim 2, wherein said first section includes said restricting portion for enabling a predetermined quantity of oil to flow from said one of said at least two branched oil passages prior to actuation of said bypass valve.

4. The lubricating system for an internal combustion engine according to claim 3, wherein said restricting portion is an orifice of a predetermined size for restricting the flow of oil from said one of said at least two branched oil passages prior to actuation of said bypass valve.

5. The lubricating system for an internal combustion engine according to claim 1, wherein said bypass valve is normally biased to a first position for preventing the flow of oil to a second passage and is moved to permit a flow of oil to said second passage when the hydraulic pressure in the oil passage exceeds the specific value.

6. The lubricating system for an internal combustion engine according to claim 5, wherein the second passage is an orifice for providing a flow of oil for lubricating a portion of said internal combustion engine.

7. A lubricating system for an internal combustion engine, comprising:

an oil passage extending from an oil pump to a discharge port in an internal combustion engine;

at least one branched oil passages for provided a restricting portion for restricting a flow of oil by reducing a diameter of said restricting portion; and

a bypass valve actuated to open when a hydraulic pressure in said oil passage exceeds a specific value, to bypass said restricting portion so as to increase the flow rate of oil through the oil passage.

8. The lubricating system for an internal combustion engine according to claim 7, wherein said at least one branched oil passage includes a first section and a second section, said second section including said bypass valve being movably mounted therein for selectively permitting oil to flow into said second section when the hydraulic pressure in the oil passage exceeds a specified value.

9. The lubricating system for an internal combustion engine according to claim 8, wherein said first section includes said restricting portion for enabling a predetermined quantity of oil to flow from said at least one branched oil passage prior to actuation of said bypass valve.

10. The lubricating system for an internal combustion engine according to claim 9, wherein said restricting portion is an orifice of a predetermined size for restricting the flow of oil from said one of said at least one branched oil passage prior to actuation of said bypass valve.

11. The lubricating system for an internal combustion engine according to claim 7, wherein said bypass valve is normally biased to a first position for preventing the flow of oil to a second passage and is moved to permit a flow of oil to said second passage when the hydraulic pressure in the oil passage exceeds the specific value.

12. The lubricating system for an internal combustion engine according to claim 11, wherein the second passage is an orifice for providing a flow of oil for lubricating a portion of said internal combustion engine.