Speed controlling an electric machine of a hybrid electric vehicle

Patent metadata

Field	Value
Publication number	US-2018050687-A1
Application number	US-201615241995-A
Country	US
Kind code	A1
Filing date	Aug 19, 2016
Priority date	Aug 19, 2016
Publication date	Feb 22, 2018
Grant date	—

Abstract

A hybrid powertrain includes an engine having a crankshaft, and an electric motor having a rotor selectively coupled to the crankshaft via a disconnect clutch. The powertrain further includes a transmission having a torque converter that has an impeller fixed to the rotor. A controller is configured to, in response to the engine starting, generate a torque command for the motor that defines a magnitude that is based on a difference between a target impeller speed and a measured impeller speed.

First claim

What is claimed is:

1 . A hybrid powertrain comprising:
an engine having a crankshaft; an electric motor including a rotor selectively coupled to the crankshaft via a disconnect clutch; a transmission including a torque converter having an impeller fixed to the rotor; and a controller configured to, in response to the engine starting, generate a torque command for the motor that defines a magnitude that is based on a difference between a target impeller speed and a measured impeller speed.

2 . The hybrid powertrain of claim 1 , wherein the torque converter further includes a bypass clutch configured to selectively lock the impeller and turbine relative to each other.

3 . The hybrid powertrain of claim 2 , wherein the controller is further configured to generate the torque command in response to the bypass clutch being open or slipping.

4 . The hybrid powertrain of claim 1 , wherein the torque command further includes a feedforward component, and a feedback component that is based on the difference between the target impeller speed and the measured impeller speed.

5 . The hybrid powertrain of claim 4 , wherein the feedforward component is based on a capacity of a torque converter bypass clutch.

6 . The hybrid powertrain of claim 1 , wherein the magnitude increases in response to the difference between the target impeller speed and the measured impeller speed increasing.

7 . The hybrid powertrain of claim 6 , wherein the magnitude decreases in response to the difference between the commanded impeller speed and the measured impeller speed decreasing.

8 . The hybrid powertrain of claim 1 , wherein the controller is further configured to command starting of the engine.

9 . The hybrid powertrain of claim 1 further comprising a speed sensor disposed within the electric motor and configured to output a speed signal indicating a measured impeller speed.

10 . A vehicle comprising:
an engine including a crankshaft; a transmission including a torque converter having an impeller, and a turbine fixed to a turbine shaft that is driveably connected to driven wheels of the vehicle, wherein the torque converter further includes a bypass clutch configured to selectively lock the impeller and turbine relative to each other; an electric machine including a rotor selectively coupled to the crankshaft via a disconnect clutch and fixed to the impeller; a speed sensor disposed within the transmission and configured to output a speed signal indicating a measured impeller speed; and at least one controller configured to, in response to a change in torque split between the engine and the electric machine, and the bypass clutch being open or slipping, generate a torque command for the electric machine that includes a feedforward component, and a feedback component that is based on an error between a target impeller speed and the measured impeller speed.

11 . The vehicle of claim 10 , wherein the change in torque split includes starting of the engine.

12 . The vehicle of claim 10 , wherein the feedforward component is based on a capacity of the bypass clutch.

13 . The vehicle of claim 10 , wherein the feedforward component is based on a capacity of the disconnect clutch.

14 . The vehicle of claim 12 , wherein the feedforward component is based on a pedal position of an accelerator pedal of the vehicle.

15 . The vehicle of claim 11 , wherein the controller is further programmed to command closing of the disconnect clutch in response to a request to start the engine.

16 . The vehicle of claim 10 , wherein a magnitude of the feedback component increases in response to the error increasing.

17 . The vehicle of claim 10 , wherein the target impeller speed is based on a measured speed of the turbine.

18 . A method of controlling an electric machine of a hybrid powertrain that includes an engine, a transmission, and a torque converter having a turbine, an impeller fixed to the electric machine, and a bypass clutch, the method comprising:
generating a command to start the engine; and in response to the command to start the engine and the bypass clutch being open or slipping, generating a speed-control torque command for the electric machine that defines a magnitude that is based on a difference between a target impeller speed and a measured impeller speed.

19 . The method of claim 18 further comprising, in response to completion of the engine starting, generating a torque-control torque command for the electric machine that defines a magnitude that is based on driver-demanded torque.

20 . The method of claim 18 further comprising, in response to the bypass clutch being closed, generating a torque-control torque command for the electric machine that defines a magnitude that is based on driver-demanded torque.

Assignees

• Ford Global Tech Llc

Inventors

• Meyer Jason
• Johri Rajit
• Doering Jeffrey Allen
• Thompson Scott James

Classifications

• B60W2050/0012

  Feedforward or open loop systems · CPC title

• B60W2050/0008

  Feedback, closed loop systems or details of feedback error signal · CPC title

• Y02T10/72

  Electric energy management in electromobility · CPC title

• B60W10/026

  of lock-up clutches · CPC title

• B60W2710/021

  Clutch engagement state · CPC title