Oil pressure switch failure detection system for outboard motor

• US 6,778,076 B2
• Filed: 12/28/2001
• Issued: 08/17/2004
• Est. Priority Date: 12/28/2000
• Status: Expired due to Term

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Keihin Corporation (Hitachi, Ltd.), Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Shidara, Sadafumi, Takahashi, Nobuhiro
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): Previl, Daniel
• Application Number:
  US10/028,360
• Publication Number:
  US 20020084897A1
• Time in Patent Office: 963 Days
• Field of Search: 340/451, 340/449, 340/450, 340/450.2, 340/450.3, 340/438, 340/439, 123/179.7, 123/179.5, 123/179.16, 123/179.17, 123/198.D, 123/196.S, 73/530.4, 73/541.6, 73/541.7, 731/521.8, 732/90.R, 737/08
• US Class Current: 340/451
• 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 1/20 concerning lubricant pressure

Abstract

An oil pressure switch failure detection system for an outboard motor, having a first oil pressure switch which generates an ON signal indicating that the oil pressure is less than or equal to a first predetermined oil pressure and a second oil pressure switch which generates an ON signal indicating that the oil pressure is less than or equal to a second predetermined oil pressure which is set higher than the first predetermined oil pressure. In the system, by discriminating whether the generated signals of the first and second oil pressure switches are equal to be expected signals expected under operating conditions of the engine, it is determined whether at least one of the first and second oil pressure switches fails. With this, it become possible to detect failure of the first and second oil pressure switches, accurately.

Claims

1. A system for detecting failure of oil pressure switches which generate signals in response to a pressure of oil to be supplied to an internal combustion engine for an outboard motor for small boats, comprising:

a first oil pressure switch which generates a signal indicating that the oil pressure is less than or equal to a first predetermined oil pressure;

a second oil pressure switch which generates a signal indicating that the oil pressure is less than or equal to a second predetermined oil pressure which is set higher than the first predetermined oil pressure;

switch signal discriminating means for discriminating whether the generated signals of the first and second oil pressure switches are equal to expected signals expected under operating conditions of the engine;

and switch failure determining means for conducting a determination as to whether at least one of the first and second oil pressure switches has failed based on a result of discrimination of the switch signal determining means.

2. A system according to claim 1, wherein the switch failure determining means conducts the determination after a predetermined period of time has passed since starting of the engine.

3. A system according to claim 2, wherein the switch failure determining means conducts the determination as to whether the second oil pressure switch fails after the predetermined period of time has passed since starting of the engine.

4. A system according to claim 3, further including:

engine speed detecting means for detecting a speed of the engine; and

wherein the switch failure determining means conducts the determination when the detected engine speed is greater than or equal to a predetermined engine speed.

5. A system according to claim 3, wherein the switch failure determining means determines that the second oil pressure switch fails when it is discriminated that the second oil pressure switch does not generate the signal equal to the expected signal consecutively during a predetermined number of determination.

6. A system according to claim 5, wherein the switch failure determining means determines that the second oil pressure switch fails when it is discriminated that the second oil pressure switch does not generate the signal equal to the expected signal consecutively during a predetermined number of determination conducted at each starting of the engine.

7. A system according to claim 2, wherein the switch failure determining means determines that the first and second oil pressure switches fail when it is discriminated that the first and second oil pressure switches do not generate the signals equal to the expected signals consecutively during a predetermined number of determination.

8. A system according to claim 7, wherein the switch failure determining means determines that the first and second oil pressure switches fail when it is discriminated that the first and second oil pressure switches do not generate the signals equal to the expected signals consecutively during a predetermined number of determination conducted at each starting of the engine.

9. A system according to claim 1, wherein the predetermined period of time is set with respect to a temperature indicative of the engine.

10. A system according to claim 9, wherein the temperature is at least one of a coolant temperature of the engine and a temperature of intake air to be supplied to the engine.

11. A system according to claim 9, wherein the predetermined period of time is set to be decreased with increasing temperature.

12. A system according to claim 1, wherein the first and second predetermined oil pressures are set to be oil pressures at a time after the engine has been warmed up.

13. A system according to claim 12, wherein the first predetermined oil pressure is set to be an oil pressure at a load when the engine is idling.

14. A system according to claim 12, wherein the second predetermined oil pressure is set to be an oil pressure at a which is greater than the load when the engine is idling.

15. A system according claim 1, further including:

alarm operating means for operating an alarm; and

wherein the alarm operating means effects the alarm when the switch failure determining means determines that at least one of the first and second oil pressure switches fails.

16. A method of detecting failure of oil pressure switches which generate signals in response to a pressure of oil to be supplied to an internal combustion engine for an outboard motor for small boats, having a first oil pressure switch which generates a signal indicating that the oil pressure is less than or equal to a first predetermined oil pressure and a second oil pressure switch which generates a signal indicating that the oil pressure is less than or equal to a second predetermined oil pressure which is set higher than the first predetermined oil pressure, comprising the steps of:

(a) discriminating whether the generated signals of the first and second oil pressure switches are equal to be expected signals expected under operating conditions of the engine; and

(b) conducting a determination as to whether at least one of the first and second oil pressure switches fails based on a result of the discrimination.

17. A method according to claim 16, wherein the step (b) conducts the determination after a predetermined period of time has passed since starting of the engine.

18. A method according to claim 17, wherein the step (b) conducts the determination as to whether the second oil pressure switch fails after the predetermined period of time has passed since starting of the engine.

19. A method according to claims 18, further including the step of:

detecting a speed of the engine; and

wherein the step (b) conducts the determination when the detected engine speed is greater than or equal to a predetermined engine speed.

20. A method according to claim 18, wherein the step (b) determines that the second oil pressure switch fails when it is discriminated that the second oil pressure switch does not generate the signal equal to the expected signal consecutively during a predetermined number of determination.

21. A method according to claim 20, wherein the step (b) determines that the second oil pressure switch fails when it is discriminated that the second oil pressure switch does not generate the signal equal to the expected signal consecutively during a predetermined number of determination conducted at each starting of the engine.

22. A method according to claim 17, wherein the step (b) determines that the first and second oil pressure switches fail when it is discriminated that the first and second oil pressure switches do not generate the signals equal to the expected signals consecutively during a predetermined number of determination.

23. A method according to claims 22, wherein the step (b) determines that the first and second oil pressure switches fail when it is discriminated that the first and second oil pressure switches do not generate the signals equal to the expected signals consecutively during a predetermined number of determination conducted at each starting of the engine.

24. A method according to claim 16, wherein the predetermined period of time is set with respect to a temperature indicative of the engine.

25. A method according to claim 24, wherein the temperature is at least one of a coolant temperature of the engine and a temperature of intake air to be supplied to the engine.

26. A method according to claim 24, wherein the predetermined period of time is set to be decreased with increasing temperature.

27. A method according to claim 16, wherein the first and second predetermined oil pressures are set to be oil pressures at a time after the engine has been warmed up.

28. A method according to claim 27, wherein the first predetermined oil pressure is set to be an oil pressure at a load when the engine is idling.

29. A method according to claim 27, wherein the second predetermined oil pressure is set to be an oil pressure at a which is greater than the load when the engine is idling.

30. A method according claim 16, further including the step of:

(c) operating an alarm; and

operates the alarm when the step (b)determines that at least one of the first and second oil pressure switches fails.