Oil pressure diagnostic strategy for a hybrid electric vehicle

• US 6,571,157 B1
• Filed: 05/17/2002
• Issued: 05/27/2003
• Est. Priority Date: 05/17/2002
• Status: Expired due to Term

• Current Assignee: Michigan Motor Technologies LLC (Equitable IP Corporation)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company), Visteon Global Technologies Incorporated (Visteon Corporation)
• Inventors: Valascho, Joseph Francis, Dahlin, Greg
• Primary Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US10/063,848
• Time in Patent Office: 375 Days
• Field of Search: 701/22, 701/84, 701/86, 701/101, 701/102, 701/104, 701/105, 701/114, 731/172, 731/173
• US Class Current: 701/22
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 2050/0006 Digital architecture hierarchy
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/1075 fluid pressure, e.g. oil pressure
• CPC Class Codes: B60W 50/04 Monitoring the functioning of the control system
• CPC Class Codes: F01M 11/10 Indicating devices; Other safety devices
• CPC Class Codes: F01M 11/12 concerning lubricant level
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A diagnostic system for controlling an engine low oil pressure indicator in a hybrid electric vehicle includes a powertrain having an engine and an electric traction motor, an oil pressure sensor/sending unit mechanically connected to the engine, an engine speed sensor/sending unit mechanically connected to the engine, a controller having connections to the oil pressure sensor and engine speed sensor, a low oil pressure indicator electrically connected to the controller, a mode selector having modes for “off” and “run/start”, the controller being configured to prevent activation of the low oil pressure indicator when the mode selector is in the “run/start” mode and the engine is not running.

Claims

1. A diagnostic system for controlling an engine low oil pressure indicator in a hybrid electric vehicle, comprising:

a powertrain having an engine and an electric traction motor;

an oil pressure sensor/sending unit mechanically connected to the engine;

an engine speed sensor/sending unit mechanically connected to the engine;

a controller having connections to the oil pressure sensor and engine speed sensor;

a low oil pressure indicator electrically connected to the controller;

a mode selector having modes for “

off” and

“

run/start”

; and

the controller configured to prevent activation of the low oil pressure indicator when the mode selector is in the “

run/start”

mode and the engine is not running.

2. The diagnostic system of claim 1, wherein the controller comprises:

an engine enabled flag;

a first delay timer;

a determination of mode selector position;

a system to set the engine enabled flag to DISABLED or ENABLED;

a system to reset, decrement, and monitor the first delay timer;

a determination of whether the engine enabled flag is ENABLED or DISABLED;

a comparison of engine oil pressure to a first predetermined threshold value;

a determination of whether data from the engine speed sensor/sending unit is missing or invalid;

a comparison of engine speed to a second predetermined threshold value;

a system to activate the low oil pressure indicator when engine oil pressure is below the first predetermined threshold value, the engine enabled flag is set to ENABLED, the engine speed data is missing or invalid and the first delay timer has expired; and

a system to activate the low oil pressure indicator when engine oil pressure is below the first predetermined threshold value, the engine enabled flag is set to ENABLED, the engine speed data is not missing or invalid, engine speed is above the second predetermined threshold value and the first delay timer has expired.

3. The diagnostic system of claim 2, further comprising a system to deactivate the low oil pressure indicator when:

engine oil pressure is above the first predetermined threshold value;

engine oil pressure is below the first predetermined threshold value, the engine enabled flag is set to ENABLED, the engine speed data is not missing or invalid and engine speed is not above the second predetermined threshold value; and

engine oil pressure is below the first predetermined threshold value, the engine enabled flag is set to ENABLED, the engine speed data is not missing or invalid and engine speed is above the second predetermined threshold value and the first delay timer has not expired.

4. The controller of claim 2, wherein the first delay timer duration is about 1 second.

5. The controller of claim 2, wherein the first predetermined threshold value for engine oil pressure is in the range of about 4.5 to about 7 pounds per square inch.

6. The controller of claim 2, wherein the second predetermined threshold value for engine speed is about 500 revolutions per minute.

7. The diagnostic system of claim 1, wherein the controller comprises:

an oil indicator test timer;

an engine speed above a second threshold delay timer;

a system to reset and monitor the oil indicator test timer;

a system to reset and monitor the engine speed above the second threshold delay timer;

a determination of mode selector position;

a determination of whether the oil pressure sensor is functioning properly;

a comparison of engine oil pressure to a first predetermined threshold value;

a determination of whether the engine speed sensor is functioning properly;

a comparison of engine speed to a second predetermined threshold value;

a system to activate the low oil pressure indicator when

the mode selector transitions from the off mode to the run/start mode,

the mode selector is in the run/start mode and the oil pressure sensor is not functioning properly,

the mode selector is in the run/start mode and the engine speed sensor is not functioning properly,

the oil pressure sensor is functioning properly, engine oil pressure is below the first predetermined threshold value, the engine speed sensor is functioning properly, engine speed is above the second predetermined threshold value and the engine speed above second threshold delay timer has expired; and

a system to deactivate the oil pressure indicator when

the mode selector is in run/start mode and the oil pressure sensor unit is functioning properly, engine oil pressure is above the first predetermined threshold value, and the oil indicator test timer has expired,

the mode selector is in the run/start mode, the oil pressure sensor/sending unit is functioning properly, engine oil pressure is below the first predetermined threshold value, the engine speed sensor is functioning properly, engine speed is below the second predetermined threshold value and the oil indicator test timer has expired.

8. The diagnostic system of claim 7, further comprising a system to send an error message to a vehicle system controller when the oil pressure sensor is not functioning properly.

9. The diagnostic system of claim 7, further comprising a system to send an error message to a vehicle system controller when the engine speed sensor is not functioning properly.

10. The diagnostic system of claim 7, wherein the oil indicator test timer has a duration of about 3 seconds.

11. The diagnostic system of claim 7, wherein the engine speed above second threshold delay timer has a duration of about 1 second.

12. The diagnostic system of claim 7, wherein the first predetermined threshold value for engine oil pressure is in a range of about 4.5 to about 7 pounds per square inch.

13. The diagnostic system of claim 7, wherein the second predetermined threshold value for engine speed is about 500 revolutions per minute.

14. The diagnostic system of claim 1, wherein the low oil pressure indicator comprises a lamp.

15. The diagnostic system of claim 1, wherein the low oil pressure indicator comprises a tone.

16. The diagnostic system of claim 1, wherein the low oil pressure indicator comprises a lamp and a tone.

17. A diagnostic method for controlling an engine low oil pressure indicator in a hybrid electric vehicle having an engine and an electric traction motor powertrain, comprising the steps of:

sensing engine oil pressure;

sensing engine speed;

inputting oil pressure sensor and engine speed sensor to a controller;

connecting a low oil pressure indicator to the controller;

indicating vehicle mode for “

off” and

“

run/start”

; and

preventing activation of the low oil pressure indicator when the mode selector is in the “

run/start”

mode and the engine is not running.

18. The diagnostic method of claim 17, further comprising the step of activating the low oil pressure indicator when engine oil pressure is below a first predetermined threshold value, an engine enabled flag is set to ENABLED, engine speed data is not missing or invalid, engine speed is above a second predetermined threshold value and a first delay timer has expired.

19. The diagnostic method of claim 18, further comprising the step of:

deactivating the low oil pressure indicator when engine oil pressure is above the first predetermined threshold value;

deactivating the low oil pressure indicator when engine oil pressure is below the first predetermined threshold value, the engine enabled flag is set to ENABLED, the engine speed data is not missing or invalid and engine speed is not above the second predetermined threshold value; and

deactivating the low oil pressure indicator when engine oil pressure is below the first predetermined threshold value, the engine enabled flag is set to ENABLED, the engine speed data is not missing or invalid and engine speed is above the second predetermined threshold value and the first delay timer has not expired.

20. An article of manufacture for operating an engine low oil pressure indicator in a hybrid electric vehicle comprising:

a low oil pressure indicator electronically connected to a controller;

a mode selector electronically connected to the controller; and

a control strategy embodied in the controller comprising an engine enabled flag,

a determination of mode selector position,

a system to set the engine enabled flag to DISABLED or ENABLED,

a determination of whether the engine enabled flag is ENABLED or DISABLED,

a comparison of engine oil pressure to a first predetermined threshold value,

a comparison of engine speed to a second predetermined threshold value,

a system to activate the low oil pressure indicator, and

a system to deactivate the low oil pressure indicator.

21. An automotive vehicle comprising:

a low oil pressure indicator electronically connected to a controller;

a mode selector electronically connected to the controller; and

a control strategy embodied in the controller comprising an engine enabled flag,

a determination of mode selector position,

a system to set the engine enabled flag to DISABLED or ENABLED,

a determination of whether the engine enabled flag is ENABLED or DISABLED,

a comparison of engine oil pressure to a first predetermined threshold value,

a comparison of engine speed to a second predetermined threshold value,

a system to activate the low oil pressure indicator, and

a system to deactivate the low oil pressure indicator.