Torque converter clutch lockup during skip-fire operation

Patent metadata

Field	Value
Publication number	US-2015232103-A1
Application number	US-201514704630-A
Country	US
Kind code	A1
Filing date	May 5, 2015
Priority date	Aug 13, 2012
Publication date	Aug 20, 2015
Grant date	—

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.

First claim

What is claimed is:

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.

Assignees

• Tula Technology Inc

Inventors

• Phillips Andrew W
• Carlson Steven E

Classifications

• F02D29/02

  peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers · CPC title

• B60W30/20 Primary

  Reducing vibrations in the driveline · CPC title

• B60W10/06

  including control of combustion engines · CPC title

• F16H2061/145

  for controlling slip, e.g. approaching target slip value · CPC title

• F02D41/0087 Primary

  Selective cylinder activation, i.e. partial cylinder operation (deceleration cut-off F02D41/123) · CPC title