SYSTEMS AND METHODS FOR ENGINE CONTROL BASED ON ENGINE OIL VISCOSITY

• US 20150066332A1
• Filed: 08/27/2013
• Published: 03/05/2015
• Est. Priority Date: 08/27/2013
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Leone, Thomas G.
• Granted Patent: US 9,624,858 B2
• Time in Patent Office: Days
• US Class Current: 701/102
• CPC Class Codes: F01M 11/10 Indicating devices; Other safety devices
• CPC Class Codes: F02D 2200/023 Temperature of lubricating oil or working fluid
• CPC Class Codes: F02D 2200/1006 Engine torque losses, e.g. friction or pumping losses or losses caused by external loads of accessories
• CPC Class Codes: F02D 31/003 for idle speed control
• CPC Class Codes: F02D 41/04 Introducing corrections for particular operating conditions F02D41/14 takes precedence
• CPC Class Codes: F16N 2200/12 Viscosity

Abstract

A method, comprising: setting an engine intake airflow parameter based on an engine oil viscosity index. In this way, engine operating conditions that depend on engine friction and engine intake airflow, such as engine idling speed and engine friction torque, may be determined and implemented with an increased consistency. This in turn may decrease the possibility of engine stalls and improve engine performance, particularly at low temperatures.

Claims

1. A method, comprising:

setting an engine intake airflow parameter based on an engine oil viscosity index.

2. The method of claim 1, further comprising:

determining an engine oil viscosity based on the engine oil viscosity index and an engine oil temperature.

3. The method of claim 2, wherein:

during an engine idling condition, the engine intake airflow parameter is further based on the engine oil viscosity and the desired engine idle speed.

4. The method of claim 2, further comprising:

during an actively engaged engine condition;

determining a desired and/or actual engine RPM;

determining an engine friction torque based on the desired and/or actual engine RPM and the engine oil viscosity.

5. The method of claim 4, further comprising:

determining a desired indicated torque based on the engine friction torque, a desired brake torque and one or more accessory torques.

6. The method of claim 5, wherein the engine intake airflow parameter is further based on the desired indicated torque.

7. The method of claim 1, where the engine intake airflow parameter is an air intake throttle angle.

8. An engine system comprising:

at least one cylinder;

at least one piston positioned in the at least one cylinder;

an air intake passage coupled to the at least one cylinder; and

a controller including instructions to;

determine a viscosity of an engine oil in the engine oil system based on a viscosity index of the engine oil and a temperature of the engine oil; and

adjust airflow through the air intake passage based on the viscosity of the engine oil.

9. The engine system of claim 8, wherein the controller further includes instructions to:

during an engine idling condition, determine a desired engine idle speed, and wherein adjusting airflow through the air intake passage is further based on the desired engine idle speed.

10. The engine system of claim 8, wherein the controller further includes instructions to:

during an actively engaged engine condition;

determine a desired and/or actual engine RPM;

determine an engine friction torque based on the desired and/or actual engine RPM and the viscosity of the engine oil.

11. The engine system of claim 10, wherein the controller further includes instructions to:

determine a desired indicated torque based on the engine friction torque, a desired brake torque and one or more accessory torques.

12. The engine system of claim 11, wherein adjusting airflow through the air intake passage is further based on the desired indicated torque.

13. The engine system of claim 8, where adjusting airflow through the air intake passage includes one or more of adjusting an angle of an air intake throttle disposed in the air intake passage, increasing intake valve lift or duration of an intake valve via a variable valve lift system, advancing intake valve opening timing via a variable valve timing system, and combinations thereof.

14. A method for an engine, comprising:

during a first condition;

increasing engine intake airflow responsive to a first engine oil viscosity and a desired engine idling speed; and

during a second condition;

decreasing engine intake airflow responsive to a second engine oil viscosity and a desired engine idling speed, the second engine oil viscosity lower than the first engine oil viscosity.

15. The method of claim 14, wherein:

prior to the first or second condition, the engine intake airflow is determined based on a standard engine oil viscosity, the standard engine oil viscosity being lower than the first engine oil viscosity and greater than the second engine oil viscosity.

16. The method of claim 14, where the first engine oil viscosity is based on a first engine oil temperature and a first engine oil viscosity index.

17. The method of claim 14, where increasing engine intake airflow includes increasing an angle of an air intake throttle and where decreasing engine intake airflow includes decreasing the angle of the air intake throttle.

18. The method of claim 14, where the second engine oil viscosity is based on a second engine oil temperature and a second engine oil viscosity index.

19. The method of claim 17, further comprising:

during a third condition;

increasing the angle of the air intake throttle if an actual idle speed is less than the desired engine idling speed.

20. The method of claim 19, further comprising:

during a fourth condition;

decreasing the angle of the air intake throttle if the actual idle speed is greater than the desired engine idling speed.