SHIFT RAIL TRANSMISSION POSITION SENSING WITH TOLERANCE FOR SENSOR LOSS

• US 20110035123A1
• Filed: 08/03/2010
• Published: 02/10/2011
• Est. Priority Date: 08/04/2009
• Status: Active Grant

• Current Assignee: Eaton Cummins Automated Transmission Technologies, LLC
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Manyala, John, Kodela, Naresh K., Anderson, Ken R., Katrak, Kerfegar K., McKenzie, Ian D., Pollack, Christopher, Fritz, Todd W., Zuppann, Richard E.
• Granted Patent: US 8,521,380 B2
• Time in Patent Office: Days
• US Class Current: 701/55
• CPC Class Codes: F16H 59/70 dependent on the ratio established
• CPC Class Codes: F16H 61/68 specially adapted for stepped gearings
• CPC Class Codes: G01B 7/30 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: Y10T 74/19251 Control mechanism

Abstract

A number N of position sensors, each associated with one of N shift rails in a shift rail transmission system, wherein the set of N sensors is divided into subsets and each subset is provided a common reference from a control module; and a processing component that determines from data from each sensor whether the shift rail associated with that sensor is in a position of engagement of a first gear, a position of engagement of a second gear, or in a neutral position.

Further, providing a first common reference to a first set of shift rail position sensors; providing a second common reference to a second set of shift rail position sensors; receiving sensor data from each position sensor; determining that the data from the first set of position sensors is unreliable; and operating a transmission using only the gears related to the position sensors in the second set.

Claims

1. A system, comprising:

a number N of position sensors, each sensor associated with one of N shift rails in a shift rail transmission system, wherein each sensor is electrically coupled to a control module that provides an electrical reference to the sensor and receives data in the form of an electrical signal from the sensor; and

wherein the set of N sensors is divided into subsets and each subset is provided a common reference from the control module; and

a processing component that determines from data from each sensor whether the shift rail associated with that sensor is in a position of engagement of a first gear, a position of engagement of a second gear, or in a neutral position.

2. The system of claim 1, further comprising a second source of position information for at least one of the N shift rails.

3. The system of claim 2, wherein the second source of position information for a rail M is a second position sensor on rail M.

4. The system of claim 1, wherein each of the N shift rails moves in one direction to engage the first gear and moves in another direction to engage the second gear, such that the N shift rails operate to engage two times N gears.

5. The system of claim 4, wherein the two times N gears are divided into subsets of gears such that the group of gears allocated to a subset is sufficient to enable operation of the transmission in forward and reverse and over a predefined range of transmission shaft speeds.

6. The system of claim 5, wherein the sensors allocated to a subset of the N sensors are associated with the gears allocated to a subset of the two times N gears.

7. The system of claim 6, wherein if the common reference to one of the subsets of N sensors becomes unavailable, the associated subset of gears is disabled.

8. The system of claim 4, wherein there is a second source of position information for at least one of the N shift rails, and the second source of position information is inferred gear from transmission shaft speeds.

9. The system of claim 8, wherein the processing component determines from the position of engagement of the shift rail an expected range of shaft speeds, and verifies that the shaft speed received as the second source of position information is within the expected range.

10. The system of claim 6, wherein the N shift rails are four shift rails, configured as follows:

a first rail with Reverse, Neutral and First/Second gear engagement positions;

a second rail with Third gear, Neutral, and Fifth gear engagement positions;

a third rail with Fourth gear, Neutral, and Sixth gear engagement positions; and

a fourth rail with Unlock and Lock engagement positions and a transition position between Unlock and Lock.

11. The system of claim 10, further comprising a second position sensor on the first rail, wherein

one subset of gears includes Reverse gear, First or Second gear, Third gear, and Fifth gear;

one subset of gears includes Reverse gear, First or Second gear, Fourth gear, and Sixth gear; and

one subset of sensors includes a sensor on the first rail, a sensor on the third rail, and a sensor on the fourth rail; and

one subset of sensors includes a sensor on the first rail and a sensor on the second rail.

12. The system of claim 4, wherein the N shift rails are four shift rails, configured as follows:

a first rail with Reverse, Neutral and First/Second gear engagement positions;

a second rail with Third gear, Neutral, and Fifth gear engagement positions;

a third rail with Fourth gear, Neutral, and Sixth gear engagement positions; and

a fourth rail with Unlock and Lock engagement positions and a transition position between Unlock and Lock.

13. The system of claim 12, further comprising a second position sensor on each of the first rail, the second rail, and the third rail, wherein the processing component cross-checks the information from one sensor on a rail with the information from the other sensor on the rail.

14. The system of claim 13, wherein

one subset of sensors includes a sensor on the first rail, a sensor on the second rail, a sensor on the third rail, and a sensor on the fourth rail;

and

one subset of sensors includes a sensor on the first rail, a sensor on the second rail, and a sensor on the third rail; and

wherein if the common reference to one of the subsets of sensors becomes unavailable, the processing component relies on the position information from the other subset of sensors.

15. The system of claim 13, wherein the processing component includes two processors, each of which receives sensor data from one of the subsets of sensors.

16. The system of claim 15, wherein one of the two processors provides position information determined from the received sensor data to the other processor.

17. The system of claim 1, wherein the processing component includes two processors, and either each processor receives the sensor data from each sensor or one of the two processors provides position information determined from the received sensor data to the other processor.

18. The system of claim 1, wherein the processing component compares position information determined from sensor data from all of the sensors to determine a trusted position.

19. The system of claim 1, in a dual-clutch shift rail transmission, wherein the processor determines the position of two shift rails to monitor the engagement of one gear concurrent with the disengagement of another during an upshift or downshift of the transmission.

20. A method, comprising:

providing a first common reference to a first set of position sensors, each position sensor attached to a shift rail of a transmission;

providing a second common reference to a second set of position sensors, each position sensor attached to a shift rail of a transmission;

receiving sensor data from each position sensor in the first set and in the second set;

determining, in a computing device, from data from each sensor whether the shift rail associated with that sensor is in a position of engagement of a first gear, a position of engagement of a second gear, or in a neutral position;

determining that the data from the first set of position sensors is unreliable; and

operating the transmission using only the gears related to the position sensors in the second set.