Controlling a clutch between an engine and a motor during a shift event in a hybrid vehicle

Patent metadata

Field	Value
Publication number	US-2016137190-A1
Application number	US-201414547210-A
Country	US
Kind code	A1
Filing date	Nov 19, 2014
Priority date	Nov 19, 2014
Publication date	May 19, 2016
Grant date	—

Abstract

A hybrid electric vehicle includes an engine, an electric motor, a transmission gearbox, and a clutch selectively coupling the engine to the electric motor. Engine speed can drop dramatically when operating at high speeds during a scheduled shift event in the gearbox. To reduce the effects felt by the engine speed change, at least one controller is provided and programmed to slip the clutch when locked in response to a drive torque, estimated to be present upon completion of an anticipated shift event, exceeding available negative torque, such as regenerative torque and engine braking torque.

First claim

What is claimed is:

1 . A vehicle comprising:
a clutch to selectively couple an engine and electric machine; and at least one controller programmed to slip the clutch when locked in response to a drive torque, estimated to be present upon completion of an anticipated shift event, exceeding available regenerative torque and engine braking torque to reduce engine torque transmitted downstream of the clutch during the anticipated shift event.

2 . The vehicle of claim 1 , wherein the available regenerative torque includes a minimum available negative torque from the electric machine.

3 . The vehicle of claim 1 , wherein the torque estimated to be present includes a difference between (i) an engine torque estimated to be available upon completion of the anticipated shift event and (ii) an engine torque prior to the shift event.

4 . The vehicle of claim 3 , wherein the engine torque estimated to be available after the anticipated shift event is an estimated engine torque when the clutch is locked.

5 . The vehicle of claim 1 , further comprising a gearbox with an input, wherein the available regenerative torque is a function of a speed of the input such that the at least one controller is programmed to slip the clutch based on the speed of the input.

6 . The vehicle of claim 5 , further comprising a torque converter having an impeller coupled to the input.

7 . The vehicle of claim 1 , wherein the at least one controller is further programmed to lock the clutch in response to a completion of the shift event.

8 . A vehicle comprising:
a clutch to selectively couple an engine and electric machine; and at least one controller programmed to modulate an amount of slip in the clutch based on an amount of drive torque, estimated to be present upon completion of an anticipated shift event, exceeding available regenerative torque and engine braking torque to reduce engine torque transmitted downstream of the clutch during the anticipated shift event.

9 . The vehicle of claim 8 , wherein the available regenerative torque includes a minimum available negative torque from the electric machine.

10 . The vehicle of claim 8 , wherein the torque estimated to be present includes a difference between (i) an engine torque estimated to be available upon completion of the anticipated shift event and (ii) an engine torque prior to the shift event.

11 . The vehicle of claim 10 , wherein the engine torque estimated to be available after the anticipated shift event is an estimated engine torque when the clutch is locked.

12 . The vehicle of claim 8 , further comprising a gearbox with an input, wherein the available regenerative torque is a function of a speed of the input such that the at least one controller is programmed to slip the clutch based on the speed of the input.

13 . The vehicle of claim 12 , further comprising a torque converter having an impeller coupled to the input.

14 . The vehicle of claim 8 , wherein the at least one controller is further programmed to lock the clutch in response to a completion of the shift event.

15 . A method of reducing shift shock in a vehicle comprising:
locking a clutch that selectively couples an electric machine to an engine; scheduling an anticipated shift event in a gearbox; and slipping the clutch in response to a torque, estimated to be present after the anticipated shift event, exceeding an available negative torque in the engine and electric machine.

16 . The method of claim 15 , wherein the available negative torque includes available engine braking torque and a minimum available negative torque from the electric machine.

17 . The method of claim 15 , wherein the torque estimated to be present includes a difference between (i) an engine torque estimated to be available after the anticipated shift event and (ii) an engine torque prior to the anticipated shift event.

18 . The method of claim 17 , wherein the clutch is locked when the slipping begins.

19 . The method of claim 15 , wherein the available negative torque in the electric machine varies as a function of a speed of an input to the gearbox such that the slipping is based on the speed of the input to the gearbox.

20 . The method of claim 15 , further comprising locking the clutch upon a completion of the shift event.

Assignees

• Ford Global Tech Llc

Inventors

• Nedorezov Felix
• Jahr Kenneth
• Gibson Alexander O'Connor
• Mccullough Todd
• Banker Adam Nathan

Classifications

• F16D48/06

  Control by electric or electronic means, e.g. of fluid pressure · CPC title

• B60W10/11

  Stepped gearings · CPC title

• B60W10/115

  with planetary gears · CPC title

• F16D2500/3027

  Torque · CPC title

• F16D2500/1066

  Hybrid · CPC title