Vehicle transmission brake launch system and method

Patent metadata

Field	Value
Publication number	US-9873431-B2
Application number	US-201715409909-A
Country	US
Kind code	B2
Filing date	Jan 19, 2017
Priority date	Jan 20, 2016
Publication date	Jan 23, 2018
Grant date	Jan 23, 2018

Abstract

A transmission launch system includes a control system and a transmission having a plurality of clutches, where actuation of combinations of a predetermined number of clutches provides powerflow for different transmission drive gears. The control system is configured to initiate a performance launch of the vehicle where the transmission is commanded to engage a combination of the predetermined number of clutches corresponding to a forward drive gear. The transmission is then commanded to engage an additional clutch to lock its output shaft such that engine torque is prevented from being transferred to vehicle drive wheels. The engine generates drive torque greater than a capacity of a vehicle brake system and the control system then commands release of the additional clutch thereby unlocking the output shaft and allowing powerflow in the forward drive gear such that the generated engine drive torque is transferred to the drive wheels to propel the vehicle.

First claim

What is claimed is:

1. A vehicle transmission brake launch system, comprising:
a transmission having a plurality of clutches and an output shaft, wherein actuation of different combinations of a predetermined number of clutches of the plurality of clutches provides powerflow for corresponding different transmission forward drive gears;
a control system configured to:
receive a command to initiate a performance launch of the vehicle;
command the transmission to engage a combination of the predetermined number of clutches corresponding to a predetermined forward gear;
command the transmission to engage an additional clutch of the plurality of clutches, thereby resulting in the transmission being in a state where the output shaft is bound and torque from an engine is prevented, by the transmission, from being transferred to drive wheels of the vehicle;
command the engine to generate drive torque, the generated drive torque being greater than a predetermined torque capacity of a foundation brake system of the vehicle; and
upon receipt of a command to launch the vehicle, command release of the additional clutch thereby unbinding the output shaft of the transmission and allowing powerflow in the predetermined forward gear such that the generated drive torque is transferred to the drive wheels to propel the vehicle.

2. The system of claim 1 , wherein the control system is further configured to:
confirm the foundation brakes are applied and vehicle brake torque is above a predetermined brake threshold;
after commanding the transmission to engage the combination of the predetermined number of clutches corresponding to the predetermined forward gear and before commanding the transmission to engage the additional clutch, command the engine to generate a predetermined amount of torque that is less than the generated drive torque and less than the torque capacity of the foundation brake system; and
transfer the predetermined amount of torque to the drive wheels through a driveline of the vehicle with the vehicle foundation brake system preventing movement of the drive wheels to thereby capture the predetermined amount of torque in the driveline to i) remove lash from the driveline, ii) preload bushings and one or more shafts of the driveline, and iii) torque an axle of the driveline against associated travel limiters.

3. The system of claim 2 , wherein the control system is further configured to:
maintain the brake torque above the predetermined brake threshold to keep driveline torque captured until the transmission is commanded to release the addition clutch, upon which an electronic stability control system of the vehicle is commanded to release the brake torque.

4. The system of claim 3 , wherein the control system is further configured to:
cause a message to be displayed via a user interface associated with an interior of the vehicle, the message instructing a brake pedal of the vehicle to be released; and
maintain the brake torque above the predetermined brake threshold independent of application of the brake pedal so as to keep driveline torque captured until the transmission is commanded to release the addition clutch.

5. The system of claim 1 , wherein the predetermined forward gear is first gear.

6. The system of claim 1 , wherein the predetermined forward gear is one of first gear and second gear; and wherein the control system is further configured to determine whether the launch will be initiated with the transmission in first gear or second gear before commanding the transmission to engage the combination of the predetermined number of clutches corresponding to the predetermined forward gear.

7. The system of claim 1 , wherein the plurality of clutches includes only five clutches, the transmission being free of any additional clutches utilized to make forward drive gears of the transmission.

8. The system of claim 7 , wherein the combination of the predetermined number of clutches corresponding to the predetermined forward gear and the additional clutch are utilized in providing powerflow for first and second gears of the transmission.

9. The system of claim 7 , wherein the combination of the predetermined number of clutches corresponding to the predetermined forward gear are utilized in providing powerflow for first gear of the transmission, and the additional clutch is utilized in providing powerflow for second gear and not for first gear.

10. The system of claim 7 , wherein the combination of the predetermined number of clutches corresponding to the predetermined forward gear are utilized in providing powerflow for second gear of the transmission, and the additional clutch is utilized in providing powerflow for first gear and not for second gear.

11. The system of claim 1 , wherein:
the predetermined forward gear is first gear;
the combination of the predetermined number of clutches corresponding to the predetermined forward gear includes two brake clutches and one rotating clutch; and
the additional clutch is a rotating clutch that, when utilized in the different combinations of the predetermined number of clutches of the plurality of clutches to provide powerflow for different forward drive gears of the transmission, provides powerflow for second through fourth and sixth gears of the transmission.

12. The system of claim 1 , wherein:
the predetermined forward gear is second gear;
the combination of predetermined number of clutches corresponding to the predetermined forward gear includes two brake clutches and one rotating clutch; and
the additional clutch is a rotating clutch that, when utilized in the different combinations of the predetermined number of clutches of the plurality of clutches to provide powerflow for different forward drive gears of the transmission, provides powerflow for first, third and fifth through seventh gears of the transmission.

13. The system of claim 1 , wherein the control system is further configured to determine a tractive effort threshold where greater torque applied to the wheels would result in wheel slip and, based on this determined tractive effort threshold, command the predetermined forward gear to be first gear or second gear.

14. The system of claim 1 , wherein the predetermined number of clutches of the plurality of clutches is three clutches such that when the additional clutch is commanded to be engaged, four clutches are engaged.

Assignees

• Sowards Michael D
• Wilder James M
• Johnson Joseph M
• Fca Us Llc

Inventors

• Sowards Michael D
• Wilder James M
• Johnson Joseph M

Classifications

• F16H2200/2012

  with four sets of orbital gears · CPC title

• F16H3/66

  composed of a number of gear trains without drive passing from one train to another · CPC title

• B60W2050/146

  Display means · CPC title

• B60W10/115

  with planetary gears · CPC title

• F16H2200/006

  the gear ratios comprising eight forward speeds · CPC title