System and method for increasing regenerative braking in a rear-wheel-drive-based platform with four-wheel-drive capability

Patent metadata

Field	Value
Publication number	US-2016339779-A1
Application number	US-201514714687-A
Country	US
Kind code	A1
Filing date	May 18, 2015
Priority date	May 18, 2015
Publication date	Nov 24, 2016
Grant date	—

Abstract

A vehicle includes a power source configured to provide drive torque, a front axle, a rear axle, and a transfer case configured to distribute drive torque from the power source between the front axle and the rear axle. The vehicle additionally includes a clutch arranged between the front axle and the transfer case. The clutch has a disengaged state and an engaged state drivingly coupling the transfer case and the front axle. The vehicle also includes a regenerative braking system configured to, in response to a braking request, provide regenerative braking torque to the rear axle. The vehicle further includes a controller. The controller is configured to, in response to a braking request and the clutch being in the disengaged state, control the clutch to shift into the engaged state to couple the regenerative braking system to the front axle and provide regenerative braking torque to the front axle.

First claim

What is claimed is:

1 . A vehicle comprising:
a power source configured to provide drive torque; a front axle; a rear axle; a transfer case configured to distribute drive torque from the power source between the front axle and the rear axle; a clutch arranged between the front axle and the transfer case, the clutch having an engaged state and a disengaged state, wherein in the engaged state the clutch drivingly couples the transfer case and the front axle; a regenerative braking system configured to, in response to a braking request, provide regenerative braking torque to the rear axle; and a controller configured to, in response to a braking request and the clutch being in the disengaged state, control the clutch to shift into the engaged state to couple the regenerative braking system to the front axle and provide regenerative braking torque to the front axle.

2 . The vehicle of claim 1 , further comprising first and second front wheels arranged on the front axle, a front differential drivingly coupling the transfer case and the front axle, a first disconnect arranged between the front differential and the first wheel and configured to, when engaged, drivingly couple the front differential and the first wheel, and a second disconnect arranged between the front differential and the second wheel and configured to, when engaged, drivingly couple the front differential and the second wheel, wherein the controller is further configured to, in response to the braking request and the first and second disconnects being disengaged, control the first and second disconnects to engage.

3 . The vehicle of claim 1 , further comprising a battery electrically coupled to the regenerative brake and having a state of charge, wherein the controller is configured to control the clutch to engage in further response to the state of charge being below an associated threshold.

4 . The vehicle of claim 1 , wherein the regenerative brake comprises an electric machine.

5 . A method of controlling a vehicle having a power source configured to supply drive torque to a rear axle, regenerative brakes configured to apply regenerative braking torque to the rear axle, and a shiftable member configured to selectively drivingly couple the power source to a front axle, the method comprising:
in response to a braking request and the shiftable member being disengaged, engaging the shiftable member to apply regenerative braking torque to the front axle.

6 . The method of claim 5 , wherein the shiftable member includes a clutch arranged between a transfer case and a front differential drivingly coupled to the front axle, and wherein engaging the shiftable member includes controlling the clutch to engage to drivingly couple the transfer case and the front differential.

7 . The method of claim 5 , wherein the shiftable member includes a clutch arranged between a front wheel and a front differential drivingly coupled to the front axle, and wherein engaging the shiftable member includes controlling the clutch to engage to drivingly couple the front differential and the front wheel.

8 . The method of claim 5 , wherein the engaging the shiftable member is in response to the braking request exceeding an associated threshold.

9 . The method of claim 8 , further comprising, in response to the braking request falling below the associated threshold, disengaging the shiftable member.

10 . A vehicle comprising:
a front wheel; a rear wheel; regenerative brakes configured to, in response to a braking request, apply regenerative braking torque to the rear wheel; a shiftable member configured to selectively couple the regenerative brake to the front wheel to apply regenerative braking torque to the front wheel; and a controller configured to, in response to a braking request and the shiftable member being disengaged, control the shiftable member to engage.

11 . The vehicle of claim 10 , further comprising a transfer case arranged between the front wheel and the rear wheel and configured to distribute torque among the front wheel and rear wheel, wherein the shiftable member includes a clutch configured to, when engaged, drivingly couple the transfer case and the front wheel.

12 . The vehicle of claim 11 , further comprising a front differential configured to drive the front wheel and a drive shaft drivingly coupled to the front differential, wherein the clutch is arranged between the transfer case and the drive shaft and configured to, when engaged, drivingly couple the transfer case and the drive shaft.

13 . The vehicle of claim 11 , further comprising a front differential configured to drive the front wheel and a drive shaft drivingly coupling the front differential and the transfer case, wherein the clutch is arranged between the front differential and the wheel and configured to, when engaged, drivingly couple the front differential and the wheel.

14 . The vehicle of claim 10 , wherein the braking request exceeds an associated threshold.

15 . The vehicle of claim 10 , wherein the controller is configured to control the shiftable member to engage in further response to a battery state of charge being below an associated threshold.

16 . The vehicle of claim 10 , wherein the regenerative brake comprises an electric machine.

Assignees

• Ford Global Tech Llc

Inventors

• Lauffer Scott J
• Rodrigues Ashok E
• Crombez Dale Scott
• Perakes Andreas E
• Tomik Filip
• Kootsillas Kevin
• Lindlbauer Michael Paul

Classifications

• B60W2720/30

  Wheel torque · CPC title

• B60W2710/18

  Braking system · CPC title

• B60K17/3465 Primary

  self-actuated means, e.g. differential locked automatically by difference of speed · CPC title

• B60Y2200/92

  Hybrid vehicles · CPC title

• B60W2710/021

  Clutch engagement state · CPC title