System and Method for Controlling an Engine Speed Limit of a Work Vehicle During a Transmission Ratio Change

• US 20130166171A1
• Filed: 12/21/2011
• Published: 06/27/2013
• Est. Priority Date: 12/21/2011
• Status: Abandoned Application

• Current Assignee: CNH Industrial America LLC (CNH Industrial N.V.)
• Original Assignee: CNH Industrial America LLC (CNH Industrial N.V.)
• Inventors: Hartman, Brian A., Kuros, Pawel
• Application Number:
  US13/332,645
• Publication Number:
  US 20130166171A1
• Time in Patent Office: Days
• US Class Current: 701/102
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 2510/1015 Input shaft speed, e.g. turbine speed
• CPC Class Codes: B60W 2510/104 Output speed
• CPC Class Codes: B60W 2710/0644 Engine speed
• CPC Class Codes: B60W 30/19 Improvement of gear change, e.g. by synchronisation or smoothing gear shift
• CPC Class Codes: F16H 2059/702 Rate of change of gear ratio, e.g. for triggering clutch engagement
• CPC Class Codes: F16H 2306/54 Synchronizing engine speed to transmission input speed
• CPC Class Codes: F16H 61/0403 Synchronisation before shifting
• CPC Class Codes: F16H 63/502 for smoothing gear shifts

Abstract

A method for controlling the speed limit of an engine of a work vehicle during a transmission ratio change is disclosed. The method may generally include receiving with a controller signals associated with an input speed and an output speed of a transmission of the work vehicle, determining a percent ratio change between a first gear ratio and a second gear ratio of the transmission as a function of the input and output speeds as the transmission is shifted from the first gear ratio to the second gear ratio, determining a target engine speed limit for the engine based on the percent ratio change and adjusting an actual engine speed limit of the engine based on the target engine speed limit as the transmission is shifted from the first gear ratio to the second gear ratio.

Claims

1. A method for controlling the speed limit of an engine of a work vehicle during a transmission ratio change, the method comprising:

receiving with a controller signals associated with an input speed and an output speed of a transmission of the work vehicle;

determining a percent ratio change between a first gear ratio and a second gear ratio of the transmission as a function of the input and output speeds as the transmission is shifted from the first gear ratio to the second gear ratio;

determining a target engine speed limit for the engine based on the percent ratio change; and

adjusting an actual engine speed limit of the engine based on the target engine speed limit as the transmission is shifted from the first gear ratio to the second gear ratio.

2. The method of claim 1, wherein adjusting an actual engine speed limit of the engine based on the target engine speed limit as the transmission is shifted from the first gear ratio to the second gear ratio comprises incrementally adjusting the actual engine speed limit towards the target engine speed limit at a predetermined rate as the transmission is shifted from the first gear ratio to the second gear ratio.

3. The method of claim 2, wherein the predetermined rate ranges from about 20 RPM/second to about 200 RPM/second.

4. The method of claim 3, wherein the predetermined rate ranges from about 20 RPM/second to about 60 RPM/second when the actual engine speed limit is being increased.

5. The method of claim 3, wherein the predetermined rate ranges from about 130 RPM/second to about 170 RPM/second when the actual engine speed limit is being decreased.

6. The method of claim 1, wherein receiving with a controller signals associated with an input speed and an output speed of a transmission of the work vehicle comprises receiving at least one signal from a first sensor configured to monitor the input speed of the transmission and receiving at least one signal from a second sensor configured to monitor the output speed of the transmission.

7. The method of claim 1, wherein determining a percent ratio change between a first gear ratio and a second gear ratio of the transmission as a function of the input and output speeds as the transmission is shifted from the first gear ratio to the second gear ratio comprises determining the percent ratio change according to the equation:

8. The method of claim 1, wherein determining a target engine speed limit for the engine based on the percent ratio change comprises determining the target engine speed limit according to the equation:

TESL=ESL1−

% RC*(ESL1−

ESL2)

wherein TESL corresponds to the target engine speed limit, % RC corresponds to the percent ratio change, ESL1 corresponds to a predetermined engine speed limit for the first gear ratio and ESL2 corresponds to a predetermined engine speed limit for the second gear ratio.

9. The method of claim 1, further comprising adjusting the actual engine speed limit based on a predetermined engine speed limit for the second gear ratio after the transmission is shifted to the second gear ratio.

10. The method of claim 9, wherein adjusting the actual engine speed limit based on a predetermined engine speed limit for the second gear ratio after the transmission is shifted to the second gear ratio comprises incrementally adjusting the actual engine speed limit towards the predetermined engine speed limit at a predetermined rate after the transmission is shifted to the second gear ratio.

11. A work vehicle having a control system for controlling engine speed limits during transmission ratio changes, the work vehicle comprising:

an engine;

a transmission coupled to the engine, the transmission having a first gear ratio and a second gear ratio;

a first sensor configured to detect an input speed of the transmission;

a second sensor configured to detect an output speed of the transmission; and

at least one controller communicatively coupled to the first and second sensors, the at least one controller being configured to determine a percent ratio change between the first and second gear ratios as a function of the input and output speeds as the transmission is shifted from the first gear ratio to the second gear ratio, determine a target engine speed limit for the engine based on the percent ratio change and adjust an actual engine speed limit of the engine based on the target engine speed limit as the transmission is shifted from the first gear ratio to the second gear ratio.

12. The vehicle of claim 11, wherein the first sensor comprises an engine governor of the engine.

13. The vehicle of claim 11, wherein the first sensor is coupled to an input shaft of the transmission.

14. The vehicle of claim 11, wherein the second sensor is coupled to an output shaft of the transmission.

15. The vehicle of claim 11, wherein the at least one controller is further configured to incrementally adjust the actual engine speed limit towards the target engine speed limit at a predetermined rate as the transmission is shifted from the first gear ratio to the second gear ratio.

16. The vehicle of claim 15, wherein the predetermined rate ranges from about 20 RPM/second to about 200 RPM/second.

17. The vehicle of claim 11, wherein the at least one controller is configured to determine the percent ratio change according to the equation:

18. The vehicle of claim 11, wherein the at least one controller is configured to determine the target engine speed limit according to the equation:

TESL=ESL1−

% RC*(ESL1−

ESL2)

wherein TESL corresponds to the target engine speed limit, % RC corresponds to the percent ratio change, ESL1 corresponds to a predetermined engine speed limit for the first gear ratio and ESL2 corresponds to a predetermined engine speed limit for the second gear ratio.

19. The vehicle of claim 11, wherein the at least one controller is further configured to adjust the actual engine speed limit based on a predetermined engine speed limit for the second gear ratio after the transmission is shifted to the second gear ratio.

20. The vehicle of claim 19, wherein the at least one controller is configured to incrementally adjust the actual engine speed limit towards the predetermined engine speed limit at a predetermined rate after the transmission is shifted to the second gear ratio.