TORQUE CONVERTER CLUTCH LOCKUP DURING SKIP-FIRE OPERATION

• US 20150232103A1
• Filed: 05/05/2015
• Published: 08/20/2015
• Est. Priority Date: 08/13/2012
• Status: Active Grant

• Current Assignee: Tula Technology, Incorporated
• Original Assignee: Tula Technology, Incorporated
• Inventors: CARLSON, Steven E., PHILLIPS, Andrew W.
• Granted Patent: US 9,422,880 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/026 of lock-up clutches
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 30/20 Reducing vibrations in the driveline
• CPC Class Codes: F02D 11/105 characterised by the function converting demand to actuation, e.g. a map indicating relations between an accelerator pedal position and throttle valve opening or target engine torque
• CPC Class Codes: F02D 13/06 Cutting-out cylinders
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 29/02 peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/022 in relation with the clutch status
• CPC Class Codes: F02D 41/123 the fuel injection being cut-off
• CPC Class Codes: F02D 41/18 by measuring intake air flow
• CPC Class Codes: F02P 5/1512 with particular means concerning an individual cylinder
• CPC Class Codes: F16H 2061/145 for controlling slip, e.g. approaching target slip value
• CPC Class Codes: F16H 61/143 using electric control means

Abstract

A variety of methods and arrangements for determining conditions when an engine-decoupling friction interface may be locked-up during skip-fire operation of an internal combustion engine are described. In some embodiments, the engine-decoupling friction interface is the lockup clutch of a torque converter situated in a powertrain that transmits motive power from the engine to a wheel. Rotation of the wheel causes vehicle motion.

Claims

1. A method of operating a vehicle having an internal combustion engine and a powertrain, wherein the powertrain includes an engine-decoupling friction interface, the method comprising:

operating the engine in a skip-fire manner to supply motive power to move the vehicle;

transferring the engine motive power through the friction interface;

locking-up the friction interface under certain engine skip-fire operating conditions.

2. The method of claim 1 wherein the engine-decoupling friction interface is selected from the group consisting of:

a lockup clutch of a torque converter;

an input clutch of an automated manual transmission;

an input clutch of a dual-clutch transmission.

3. A method as recited in claim 1 wherein the certain engine skip-fire operation conditions produce little or no vibration at the first and second powertrain resonances.

4. A method as recited in claim 1 wherein the certain engine skip-fire operation conditions correspond to a predetermined set of engine skip-fire operation conditions.

5. A method as recited in claim 1 wherein the powertrain includes a multi-speed transmission.

6. A method as recited in claim 1 wherein the certain engine skip-fire operation condition varies depending on the current transmission gear setting.

7. A method as recited in claim 1 wherein the certain engine skip-fire operation condition predominately produces frequencies in the vicinity of the tuned absorber mode frequency of the powertrain.

8. A method as recited in claim 1 wherein the certain engine skip-fire operation condition predominately produces frequencies in the vicinity of the low response above the second powertrain resonance.

9. A method as recited in claim 2 where there is no slip in the torque converter clutch.

10. A method as recited in claim 2 where the slip in the torque converter clutch is less than a value selected from the group consisting of 5, 10, and 20 revolutions per minute.

11. A method as recited in claim 1 where the certain engine skip-fire operation condition is determined from a library of known acceptable conditions.

12. A method as recited in claim 1 where the certain engine skip-fire operation condition is determined algorithmically based at least in part on the engine speed.

13. A method as recited in claim 1 where operating the engine in a skip-fire manner includes selecting a firing sequence which delivers substantially the required average torque and avoids generating frequencies at powertrain resonances.

14. A method as recited in claim 1 wherein the certain engine skip-fire operation condition varies depending on the current engine speed.

15. A method as recited in claim 1 wherein the certain engine skip-fire operation condition varies depending on the current per cylinder torque.

16. A method as recited in claim 1 wherein the certain engine skip-fire operation condition varies depending on the current firing fraction.

17. A method as recited in claim 1 wherein the powertrain includes a continuously variable transmission.

18. A method of operating a vehicle having an internal combustion engine and a powertrain, wherein the powertrain includes an engine-decoupling friction interface, the method comprising:

operating the engine in a skip-fire manner at sub-optimal fuel efficiency conditions to supply motive power to move the vehicle;

transferring the engine motive power through the friction interface;

locking-up the friction interface so that losses in the engine-decoupling friction interface are minimized so as to provide overall optimum vehicle fuel efficiency.