System and method for selecting a driveline gear ratio

• US 9,657,833 B2
• Filed: 08/15/2013
• Issued: 05/23/2017
• Est. Priority Date: 08/16/2012
• Status: Active Grant

• Current Assignee: Jaguar Land Rover Limited (TATA Motors Limited)
• Original Assignee: Jaguar Land Rover Limited (TATA Motors Limited)
• Inventors: Fairgrieve, Andrew, Woolliscroft, Daniel, Kelly, James
• Primary Examiner(s): Wright, Dirk
• Application Number:
  US14/421,918
• Publication Number:
  US 20150219210A1
• Time in Patent Office: 1,377 Days
• Field of Search: None
• CPC Class Codes: B60K 28/16 responsive to, or preventing, skidding of wheels brake control systems for vehicle drive stability B60T8/1755; arrangements responsive to a speed condition for adjusting wheel braking force B60T8/32; control of vehicle driving stability otherwise than by controlling the propulsion unit only B60W30/02; preventing wheel slippage by reducing power in rail vehicles B61C15/00
• CPC Class Codes: B60K 31/02 including electrically actuated servomechanism including an electric control system or a servomechanism in which the vehicle velocity affecting element is actuated electrically
• CPC Class Codes: B60K 31/04 and means for comparing one electrical quantity, e.g. voltage, pulse, waveform, flux, or the like, with another quantity of a like kind, which comparison means is involved in the development of an electrical signal which is fed into the controlling means
• CPC Class Codes: B60T 2201/04 Hill descent control
• CPC Class Codes: B60T 2210/14 Rough roads, bad roads, gravel roads
• CPC Class Codes: B60T 2210/16 Off-road driving conditions
• CPC Class Codes: B60T 2220/04 Pedal travel sensor, stroke sensor; Sensing brake request
• CPC Class Codes: B60T 2260/06 Active Suspension System
• CPC Class Codes: B60T 8/175 Brake regulation specially adapted to prevent excessive wheel spin during vehicle acceleration, e.g. for traction control safety devices for propulsion unit control responsive to, or preventing, skidding of wheels B60K28/16
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 10/111 with separate change-speed gear trains arranged in series
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/26 Wheel slip
• CPC Class Codes: B60W 2552/05 Type of road, e.g. motorways, local streets, paved or unpaved roads
• CPC Class Codes: B60W 2710/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2720/30 Wheel torque
• CPC Class Codes: B60W 30/14 Adaptive cruise control
• CPC Class Codes: B60W 30/143 Speed control B60W30/16 takes precedence
• CPC Class Codes: B60W 30/146 Speed limiting
• CPC Class Codes: B60Y 2200/20 Off-Road Vehicles
• CPC Class Codes: F16H 2061/0216 : Calculation or estimation of post shift values for different gear ratios, e.g. by using engine performance tables
• CPC Class Codes: F16H 2061/0234 : Adapting the ratios to special vehicle conditions
• CPC Class Codes: F16H 59/44 : dependent on machine speed of the machine, e.g. the vehicle
• CPC Class Codes: F16H 59/66 : Road conditions, e.g. slope, slippery
• CPC Class Codes: F16H 61/0213 : characterised by the method for generating shift signals
• CPC Class Codes: F16H 61/0437 : by using electrical signals F16H61/0403 and F16H61/061 take precedence
• CPC Class Codes: F16H 61/16 : Inhibiting or initiating shift during unfavourable conditions, e.g. preventing forward reverse shift at high vehicle speed, preventing engine over speed unintentional control input F16H61/18

Abstract

A method for selecting a gear ratio for a driveline of vehicle is provided. The method comprises gathering information relating to one or more parameters associated with the vehicle and anticipating, based on the gathered information, an occurrence of an event relating to the vehicle for which a change in driveline gear ratio is needed. The method further comprises identifying a suitable driveline gear ratio for the anticipated event, generating a command signal representative of a request to change the gear ratio of the driveline to the identified gear ratio, and communicating the command signal to a driveline subsystem of the vehicle. A system comprising an electronic control unit configured to perform the method is also provided.

Claims

1. A method for selecting a gear ratio of a vehicle driveline, comprising:

gathering information relating to one or more parameters associated with the vehicle, the information comprising information relating to the nature of a terrain over which the vehicle is traveling;

anticipating, based on the gathered information, an occurrence of an event relating to the vehicle for which a change in driveline gear ratio is needed;

identifying a suitable driveline gear ratio for the anticipated event;

generating a command signal representative of a request to change the gear ratio of the driveline to the identified gear ratio; and

communicating the command signal to a driveline subsystem of the vehicle,

the method further comprising ignoring or suspending generation of the command signal representative of a request to change the gear ratio in dependence on the current or expected amount of load on the driveline and a roughness of a ground surface of the terrain over which the vehicle is travelling.

2. The method of claim 1, wherein the information gathered in the gathering step comprises information related to one of the actual speed of the vehicle and a desired vehicle speed.

3. The method of claim 1, wherein the driveline gear ratio comprises one of a transmission gear ratio and a transfer case gear ratio.

4. The method of claim 1, further comprising, when the command signal is ignored or suspended, relieving the driveline of existing torque therein prior to changing the driveline gear ratio, and then changing the driveline gear ratio to the identified gear ratio.

5. The method of claim 4, wherein the relieving step comprises matching the speeds of an input shaft and an output shaft of the driveline.

6. The method of claim 5, wherein the matching of the speeds of the input and output shafts comprises adding one or both of positive and negative torque to the driveline.

18. The method of claim 1, further comprising determining the nature of the terrain has changed after the ignoring or suspending generation of the command signal, and initiating the requested gear ratio change in response to the determination that the nature of the terrain has changed.

19. The method of claim 1, further comprising determining the request to change the gear ratio was unintentional, based upon at least the nature of the terrain.

20. The method of claim 19, wherein the determination that the request to change the gear ratio was unintentional is based at least upon the roughness of the terrain.

21. The method of claim 1, wherein the roughness of the ground surface of the terrain includes at least an indication whether the ground surface is on-road or off-road.

7. A method for selecting a gear ratio for a driveline of a vehicle, comprising:

gathering information relating to one or more parameters associated with the vehicle, the information comprising information relating to the nature of a terrain over which the vehicle is traveling;

predicting, based on the gathered information, a need for a change in the gear ratio of the driveline from a current first gear ratio to a second gear ratio; and

effecting the change to the driveline gear ratio to the second gear ratio in response to the predicted need to do so;

the method further comprising not effecting the change to the driveline gear ratio in dependence on the current or expected amount of load on the driveline and a roughness of a ground surface of the terrain over which the vehicle is travelling.

8. The method of claim 7, wherein the information gathered in the gathering step comprises one of the actual speed of the vehicle and a desired vehicle speed.

9. The method of claim 7, further comprising, when the change to the driveline gear ratio is not effected due to the current or expected amount of load on the driveline, relieving the driveline of existing torque therein prior to changing the driveline gear ratio.

10. The method of claim 7, wherein the driveline gear ratio comprises one of a transmission gear ratio and a transfer case gear ratio.

11. A system for selecting a gear ratio for a driveline of a vehicle, comprising:

an electronic control unit, configured to;

receive information relating to one or more parameters associated with the vehicle, the information comprising information relating to a terrain over which the vehicle is traveling;

predict, based on the gathered information, a need for a change in the gear ratio of the driveline from a current first gear ratio to a second gear ratio; and

effect the change in the driveline gear ratio to the second gear ratio in response to the predicted need to do so;

the electronic control unit being further configured not to effect the change in the driveline gear ratio in dependence on the current or expected amount of load on the driveline and a roughness of a ground surface of the terrain over which the vehicle is travelling.

12. The system of claim 11, wherein the electronic control unit is configured to effect the change in the driveline gear ratio by:

generating a command signal representative of a request to change the gear ratio of the driveline to the second gear ratio; and

communicating the command signal to a driveline subsystem of the vehicle.

13. The system of claim 11, wherein the electronic control unit is configured to predict the need for a change in the driveline gear ratio by anticipating, based on the received information, an occurrence of an event relating to the vehicle for which a change in the driveline gear ratio is needed.

14. The system of claim 11, wherein the electronic control unit comprises an electronic control unit of a speed control system of the vehicle.

15. The system of claim 11, wherein the information received by the electronic control unit comprises information relating to one of the actual speed of the vehicle and a desired vehicle speed.

16. The system of claim 11, wherein the electronic control unit is further configured to cause, when the change in the driveline gear ratio is not effected in dependence on the current or expected amount of load on the driveline, the driveline to be relieved of existing torque therein prior to the changing of the driveline gear ratio to the second gear ratio.

17. A vehicle comprising the system recited in claim 11.