Vehicle idle and launch control

• US 9,944,288 B1
• Filed: 03/27/2017
• Issued: 04/17/2018
• Est. Priority Date: 03/27/2017
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Hu, Guopeng, Dai, Zhengyu, Henel, Christoph, Atluri, Sathish, Xu, Yang
• Primary Examiner(s): Young, Edwin A
• Application Number:
  US15/469,991
• Time in Patent Office: 386 Days
• CPC Class Codes: B60T 2201/06 Hill holder; Start aid systems on inclined road
• CPC Class Codes: B60T 2260/04 Automatic transmission
• CPC Class Codes: B60T 2260/09 Complex systems; Conjoint control of two or more vehicle active control systems
• CPC Class Codes: B60T 7/122 for locking of reverse movement
• CPC Class Codes: B60T 8/17 Using electrical or electronic regulation means to control braking detecting or indicating faulty operation B60T8/885
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 10/115 with planetary gears
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 2510/0275 Clutch torque
• CPC Class Codes: B60W 2510/106 Output power
• CPC Class Codes: B60W 2520/04 Vehicle stop
• CPC Class Codes: B60W 2520/30 Wheel torque
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2710/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2710/18 Braking system
• CPC Class Codes: B60W 30/18054 at stand still, e.g. engine in idling state hill holding B60W30/18118
• CPC Class Codes: B60W 30/18118 : Hill holding

Abstract

A transmission controller implements a neutral idle feature to reduce fuel consumption. A brake controller implements a Hill Start Assist feature to prevent roll-back when a vehicle is launching on an uphill grade. The transmission controller and the brake controller communicate to implement these features in a synergistic manner. Within certain road grade ranges, the transmission requests Hill Start Assist before activating neutral idle and does not activate neutral idle until it receives confirmation that Hill Start Assist is active. The transmission controller provides a powertrain torque estimate to the brake controller which the brake controller uses to determine when to release the brakes during an assisted start.

Claims

1. A vehicle comprising:

a braking system configured to respond to a Hill Start Assist (HSA) request by maintaining wheel brake torque to hold the vehicle on a grade until an estimated powertrain torque is sufficient to prevent roll back; and

a transmission configured to respond to brake pedal application with the vehicle stationary by requesting HSA and to respond to confirmation of activation of HSA by releasing a clutch to enter a neutral idle mode.

2. The vehicle of claim 1 wherein the transmission comprises:

a torque converter having an impeller and a turbine; and

a gearbox configured to selectively establish each of a plurality of power flow paths by engaging subsets of a plurality of clutches, the plurality of clutches including the clutch that is released to enter the neutral idle mode.

3. The vehicle of claim 1 wherein:

the transmission comprises a transmission controller; and

the brake system comprises a brake controller in communication with the transmission controller.

4. The vehicle of claim 3 further comprising a controller area network providing communication between the brake controller and the transmission controller.

5. A vehicle control system comprising:

a brake controller programmed to respond to a Hill Start Assist (HSA) request by maintaining wheel brake torque to hold a vehicle on a grade and sending an HSA confirmation; and

a transmission controller programmed to respond to brake pedal application with the vehicle stationary by sending the HSA request and to respond to receiving the HSA confirmation by releasing a clutch to enter a Neutral Idle mode.

6. The vehicle control system of claim 5 wherein the brake controller is programmed to release wheel brake torque in response to an estimated powertrain torque exceeding a torque required to hold the vehicle on a present grade.

7. The vehicle control system of claim 6 wherein the estimated powertrain torque is communicated to the brake controller by the transmission controller.

8. The vehicle control system of claim 7 wherein the estimated powertrain torque is proportional to a torque capacity of the clutch.

9. The vehicle control system of claim 7 wherein the estimated powertrain torque is based on measured speeds of a torque converter impeller and a torque converter turbine.

10. A transmission comprising:

a torque converter;

a gearbox configured to selectively establish a power flow path from the torque converter to an output shaft; and

a controller programmed to respond to brake pedal application with the output shaft stationary by

sending a Hill Start Assist (HSA) request to a braking system, and

after receiving confirmation that the braking system will maintain wheel brake torque to hold a vehicle on a grade, releasing a clutch to disengage the power flow path.

11. The transmission of claim 10 wherein the controller is further programmed to send an estimated powertrain torque to a brake controller.

12. The transmission of claim 11 wherein the controller is further programmed to calculate the estimated powertrain torque based on a torque capacity of the clutch.

13. The transmission of claim 11 wherein the controller is further programmed to calculate the estimated powertrain torque based on measured speeds of a torque converter impeller and a torque converter turbine.