Method and system for automated control of transmission ratio change

• US 8,965,645 B2
• Filed: 06/25/2009
• Issued: 02/24/2015
• Est. Priority Date: 06/25/2009
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation)
• Inventors: Ahn, Samuel S.
• Primary Examiner(s): MARC-COLEMAN, MARTHE Y
• Application Number:
  US12/492,066
• Publication Number:
  US 20100332090A1
• Time in Patent Office: 2,070 Days
• Field of Search: 701/65, 701/59, 701/53, 701/58, 477/98, 477/45, 477/108, 477/97, 477/144
• US Class Current: 701/58
• CPC Class Codes: F16H 2061/0227 Shift map selection, i.e. methods for controlling selection between different shift maps, e.g. to initiate switch to a map for up-hill driving
• CPC Class Codes: F16H 59/60 Inputs being a function of ambient conditions
• CPC Class Codes: F16H 61/0213 characterised by the method for generating shift signals

Abstract

The present invention relates to a method and system for automated control of transmission ratio change which balances the requirements for power with energy efficiency. A plurality of sensors detect environmental conditions of a vehicle. An environmental conditions analysis unit analyzes the environmental conditions to determine whether the detected environmental conditions indicate a likelihood of a transmission ratio increase. When the detected environmental conditions indicate the likelihood of the transmission ratio increase, an automatic transmission changes in operation from a normal state to a prepared state. However, after a predetermined amount of time, the automatic transmission changes from the prepared state back to the normal state when there is no user indication that the transmission ratio should be increased.

Claims

1. A method for automated control of transmission ratio change of a transmission for a first vehicle, the method comprising:

detecting environmental conditions of the first vehicle;

determining whether the detected environmental conditions indicate a likelihood of a transmission ratio increase based on whether a longitudinal acceleration of the first vehicle is sufficient to pass a second vehicle;

maintaining the operation of the transmission in a normal state when the detected environmental conditions indicate no likelihood of the transmission ratio increase;

changing the operation of the transmission from the normal state to a prepared state when the detected environmental conditions indicate the likelihood of the transmission ratio increases;

detecting, using an acceleration pedal sensor, an acceleration input by a user of the first vehicle;

changing the operation of the transmission from the prepared state to the normal state for preserving energy efficiency when the acceleration input is greater than an acceleration input threshold value for a downshift or a transmission ratio increase, the acceleration input threshold value for the downshift or the transmission ratio increase being stored in a shift map of the first vehicle;

maintaining a time count to determine whether a user indication that the transmission ratio should be increased is received within a predetermined period of time; and

automatically changing the operation of the transmission from the prepared state to the normal state after the predetermined amount of time has lapsed even when the acceleration input is not greater than the acceleration input threshold value for the downshift or the transmission ratio increase.

2. The method of claim 1 wherein the user indication that the transmission ratio should be increased includes rotating a steering wheel beyond a predetermined rotational threshold.

3. The method of claim 1 wherein the environmental conditions further include at least one of a distance to the second vehicle, an engine input speed, an engine output speed, a longitudinal speed, a steering wheel rotation, or a turn signal activation data.

4. The method of claim 1 further comprising maintaining an operation of the transmission in the normal state with no likelihood of the transmission ratio increase when an alternate transmission control mode is active, wherein the alternate transmission control mode is at least one of a cruise control mode, a snow mode, or an electric power only mode.

5. The method of claim 1 wherein the prepared state includes increasing a hydraulic pressure in the transmission.

6. The method of claim 1 wherein the prepared state includes increasing the transmission ratio.

7. A method for automated control of transmission ratio change of a transmission, the method comprising:

maintaining an operation of the transmission in a normal state with no likelihood of a transmission ratio increase when an alternate transmission control mode is active;

detecting environmental conditions of a first vehicle, the environmental conditions including a longitudinal acceleration of the first vehicle, a longitudinal acceleration of a second vehicle, and at least one of a distance to the second vehicle, an engine input speed, an engine output speed, a longitudinal speed, a steering wheel rotation, or turn signal activation data;

determining whether the detected environmental conditions indicate a likelihood of a transmission ratio increase based on whether the longitudinal acceleration of the first vehicle is sufficient as compared with the longitudinal acceleration of the second vehicle in order for the first vehicle to pass the second vehicle;

changing the operation of the transmission from the normal state to a prepared state when the detected environmental conditions indicate the likelihood of the transmission ratio increase and the alternate transmission mode is not active;

detecting, using an acceleration pedal sensor, an acceleration input by a user of the first vehicle;

changing the operation of the transmission from the prepared state to the normal state for preserving energy efficiency when the acceleration input is greater than an acceleration input threshold value for a downshift or a transmission ratio increase, the acceleration input threshold value for the downshift or the transmission ratio increase being stored in a shift map of the first vehicle;

changing the operation of the transmission from the prepared state to the normal state when the steering wheel rotation indicates no likelihood of the transmission ratio increase;

maintaining, using a timer, a time count to determine whether a user indication that the transmission ratio should be increased is received within a predetermined period of time; and

automatically changing the operation of the transmission from the prepared state to the normal state after the predetermined amount of time has lapsed even when the acceleration input is not greater than the acceleration input threshold value for the downshift or the transmission ratio increase and even when the steering wheel rotation does not indicate that there is no likelihood of the transmission ratio increase.

8. The method of claim 7 wherein the prepared state includes increasing a hydraulic pressure in the transmission.

9. The method of claim 7 wherein the prepared state includes increasing the transmission ratio.

10. The method of claim 7 wherein the alternate transmission control mode is at least one of a cruise control mode, a snow mode, or an electric power only mode.

11. A system for automated control of transmission ratio change comprising:

a power train control module configured to maintain an operation of a transmission in a normal state with no likelihood of a transmission ratio increase when an alternate transmission control mode is active;

a sensor detecting environmental conditions of a first vehicle that include a longitudinal acceleration of the first vehicle and a longitudinal acceleration of a second vehicle;

an engine sensor configured to detect an engine input speed and an engine output speed;

an acceleration pedal sensor configured to detect an acceleration input by a user of the first vehicle; and

an environmental conditions analysis unit configured to;

determine whether a ratio of the engine input speed over the engine output speed is greater than an engine input speed over engine output speed ratio threshold value stored in a look-up table of the environmental conditions analysis unit, and

determine whether the detected environmental conditions indicate a likelihood of a transmission ratio increase based on whether the longitudinal acceleration of the first vehicle is sufficient as compared with the longitudinal acceleration of the second vehicle in order for the first vehicle to pass the second vehicle, the step of determining whether the detected environmental conditions indicate the likelihood of the transmission ratio increase being performed when or after the ratio of the engine input speed over the engine output speed is determined to be greater than the engine input speed over engine output speed ratio threshold value,

wherein the power train control module is further configured to;

maintain the operation of the transmission in the normal state when the detected environmental conditions indicate no likelihood of the transmission increase,

change the operation of the transmission from the normal state to a prepared state when the detected environmental conditions indicate the likelihood of the transmission ratio increase and the alternate transmission mode is not active, and

change the operation of the transmission from the prepared state to the normal state for preserving energy efficiency when the acceleration input is greater than an acceleration input threshold value for a downshift or a transmission ratio increase, the acceleration input threshold value for the downshift or the transmission ratio increase being stored in a shift map of the first vehicle.

12. The system of claim 11 wherein the environmental conditions analysis unit is further configured to maintain a time count to determine whether a user indication that the transmission ratio should be increased is received within a predetermined period of time, and

wherein the power train control module is configured to change the operation of the transmission from the prepared state to the normal state after the predetermined amount of time has lapsed even when the ratio of the engine input speed over the engine output speed is not greater than the engine input speed over engine output speed ratio threshold value and even when the acceleration input is not greater than the acceleration input threshold value for the downshift or the transmission ratio increase.

13. The system of claim 11 wherein the environmental conditions include at least one of a distance to the second vehicle, a longitudinal speed, a steering wheel rotation, or a turn signal activation data.

14. The system of claim 11 wherein the alternate transmission control mode is at least one of a cruise control mode or a snow mode.

15. The system of claim 11 wherein the prepared state includes increasing a hydraulic pressure in the transmission.

16. The system of claim 11 wherein the prepared state includes increasing the transmission ratio.