Hybrid vehicle including a prevent powertrain gear hunting strategy

Patent metadata

Field	Value
Publication number	US-9475483-B2
Application number	US-201414547566-A
Country	US
Kind code	B2
Filing date	Nov 19, 2014
Priority date	Nov 19, 2014
Publication date	Oct 25, 2016
Grant date	Oct 25, 2016

Abstract

A vehicle is provided. The vehicle includes an engine, a motor, and a controller. The controller is programmed to inhibit a scheduled transmission downshift and increase a torque of the motor for a specified period of time in response to a torque demand being greater than a maximum torque capability of the engine but less than a maximum combined torque capability of the engine and motor. Upon expiration of the specified period of time, the controller may permit the downshift to occur. The specified period of time may be based on a state of charge of a battery at a time when the torque demand exceeds the maximum torque capability of the engine.

First claim

What is claimed is:

1. A vehicle comprising:
an engine;
a motor; and
a controller programmed to, in response to a torque demand being greater than a maximum torque capability of the engine but less than a maximum combined torque capability of the engine and motor, inhibit a scheduled transmission downshift and increase a torque of the motor for a specified period of time and, and upon expiration of the specified period of time, permit the downshift to occur.

2. The vehicle of claim 1 , wherein the controller is further programmed to, in response to the torque demand falling below the maximum torque capability of the engine prior to the expiration of the specified period of time, maintain a current transmission gear selection.

3. The vehicle of claim 1 , wherein the controller is further programmed to, in response to the torque demand being greater than the maximum combined torque capability of the engine and motor, permit the scheduled transmission downshift.

4. The vehicle of claim 1 , wherein the vehicle further comprises a torque converter having a lock-up clutch and wherein the controller is further programmed to inhibit a transition of the lock-up clutch from a locked condition to an unlocked condition for the specified period of time and, upon expiration of the specified period of time, permit the transition of the lock-up clutch from the locked condition to the unlocked condition.

5. The vehicle of claim 4 , wherein the controller is further programmed to, in response to the torque demand falling below the maximum torque capability of the engine prior to the expiration of the specified period of time, maintain the locked condition of the lock-up clutch.

6. The vehicle of claim 4 , wherein the controller is further programmed to, in response to the torque demand being greater than the maximum combined torque capability of the engine and motor, permit the transition of the lock-up clutch from a locked condition to an unlocked condition.

7. The vehicle of claim 1 , wherein the specified period of time is based on a state of charge of a battery at a time when the torque demand exceeds the maximum torque capability of the engine.

8. A vehicle comprising:
an engine;
an electric-machine;
a battery; and
a controller programmed to, in response to a torque demand exceeding a torque limit of the engine but not a combined torque limit of the engine and electric-machine,
prevent, for a specified period of time based on a state of charge of the battery, a downshift,
increase, for the specified period of time, a torque output by the electric-machine, and
upon expiration of the specified period of time, permit the downshift and decrease the torque output on the electric-machine.

9. The vehicle of claim 8 , wherein the controller is further programmed to, in response to the torque demand falling below the torque limit of the engine prior to the expiration of the specified period of time, maintain a current transmission gear selection.

10. The vehicle of claim 8 , wherein the controller is further programmed to, in response to the torque demand being greater than the combined torque limit of the engine and electric-machine, permit the downshift.

11. The vehicle of claim 8 , wherein the vehicle further comprises a torque converter having a lock-up clutch and wherein the controller is further programmed to inhibit a transition of the lock-up clutch from a locked condition to an unlocked condition for the specified period of time and, upon expiration of the specified period of time, permit the transition of the lock-up clutch from the locked condition to the unlocked condition.

12. The vehicle of claim 11 , wherein the controller is further programmed to, in response to the torque demand falling below the torque limit of the engine prior to the expiration of the specified period of time, maintain the locked condition of the lock-up clutch.

13. The vehicle of claim 11 , wherein the controller is further programmed to, in response to the torque demand being greater than the combined torque limit of the engine and electric-machine, permit the transition of the lock-up clutch from a locked condition to an unlocked condition.

14. A method of controlling a hybrid vehicle having an engine and an electric-machine comprising:
in response to a torque demand greater than a maximum engine torque capacity but less than a maximum combined engine and electric-machine torque capacity,
increasing an electric-machine torque,
inhibiting a scheduled transmission downshift for a specified period of time, and
permitting the scheduled downshift to occur after the specified period of time has expired.

15. The method of claim 14 , further comprising:
in response to the torque demand falling below the maximum engine torque capacity prior to expiration of the specified period of time,
maintaining a current transmission gear selection.

16. The method of claim 14 , further comprising:
in response to the torque demand being greater than the maximum combined engine and electric-machine torque capacity,
permitting the scheduled transmission downshift.

17. The method of claim 14 , wherein the hybrid vehicle further comprises a torque converter having a lock-up clutch, further comprising:
in response to the torque demand being greater than the maximum engine torque capacity but less than the maximum combined engine and electric-machine torque capacity,
inhibiting a transition of the lock-up clutch from a locked condition to an unlocked condition during the specified period of time.

18. The method of claim 17 , further comprising:
in response to the torque demand falling below the maximum engine torque capacity prior to expiration of the specified period of time,
maintaining the locked condition of the lock-up clutch.

19. The method of claim 18 , further comprising:
in response to the torque demand being greater than the maximum combined engine and electric-machine torque capacity,
permitting the transition of the lock-up clutch from the locked condition to the unlocked condition.

20. The method of claim 14 , wherein the specified period of time is based on a state of charge of a battery at a time when the torque demand exceeds maximum engine torque capacity.

Assignees

• Ford Global Tech Llc

Inventors

• Johri Rajit
• Kuang Ming Lang
• Yamazaki Mark Steven
• Wang Xiaoyong
• Liang Wei
• Doering Jeffrey Allen

Classifications

• F16H2059/147

  Transmission input torque, e.g. measured or estimated engine torque · CPC title

• F16H59/14

  Inputs being a function of torque or torque demand · CPC title

• B60Y2200/92

  Hybrid vehicles · CPC title

• F16H61/16

  Inhibiting  {or initiating}  shift during unfavourable conditions  {, e.g. preventing forward-reverse shift at high vehicle speed, preventing engine overspeed}   (F16H61/18 takes precedence) · CPC title

• F16H2061/022

  Calculation or estimation of optimal gear ratio, e.g. best ratio for economy drive or performance according driver preference, or to optimise exhaust emissions · CPC title