METHOD FOR MONITORING A MOTOR SPEED SENSOR

• US 20090105898A1
• Filed: 10/08/2008
• Published: 04/23/2009
• Est. Priority Date: 10/23/2007
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG, Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Original Assignee: BMW AG (Bayerische Motoren Werke AG), Daimler AG (Mercedes-Benz Group AG), GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust), Chrysler LLC (Stellantis NV)
• Inventors: Naqi, Syed, Van Horn, Charles J., Wu, Peter E., Wang, Wei D.
• Granted Patent: US 7,555,374 B2
• Time in Patent Office: Days
• US Class Current: 701/29
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/40 characterised by the assembly or relative disposition of components
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/50 Control strategies for responding to system failures, e.g. for fault diagnosis, failsafe operation or limp mode
• CPC Class Codes: B60W 2050/0006 Digital architecture hierarchy
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/0657 Engine torque
• CPC Class Codes: B60W 2510/081 Speed
• CPC Class Codes: B60W 2510/1015 Input shaft speed, e.g. turbine speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 50/02 Ensuring safety in case of control system failures, e.g. by diagnosing, circumventing or fixing failures
• CPC Class Codes: F16H 2037/0873 with switching, e.g. to change ranges
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility

Abstract

A method for detecting speed faults in a hybrid powertrain having engine and electric machine speed inputs includes directly sensing the engine and machine speeds and performing comparisons of sensed engine speed with engine speed determined based upon the machine speeds.

Claims

1. Method to monitor a powertrain system including a transmission device including an input member and a first sensor operative to monitor rotation of the input member, a plurality of torque machines and a corresponding plurality of rotational speed sensing devices, an output member, and first and second control modules, the method comprising:

signally connecting the first sensor directly to the first control module and directly to the second control module;

signally connecting the rotational speed sensing devices directly to the second control module;

monitoring signal inputs from the first sensor in the first and second control modules;

monitoring signal inputs from the rotational speed sensing devices in the second control module;

determining a first rotational speed of the input member based upon the signal inputs from the first sensor;

determining a second rotational speed of the input member based upon the signal inputs from the first sensor;

determining rotational speeds of the torque machines based upon the signal inputs from the rotational speed sensing devices;

calculating a third rotational speed of the input member based upon the rotational speeds of the torque machines;

comparing the first rotational speed to the third rotational speed and comparing the second rotational speed to the third rotational speed; and

detecting an input speed fault when the third rotational speed differs from the first rotational speed by an amount greater than a first threshold and the third rotational speed differs from the second rotational speed by an amount greater than a second threshold.

2. The method of claim 1, further comprising:

determining the signal inputs from the plurality of rotational speed sensing devices are valid when at least one of

the third rotational speed differs from the first rotational speed by an amount less than the first threshold and

the third rotational speed differs from the second rotational speed by an amount less than the second threshold.

3. The method of claim 1, further comprising:

disabling operation of the torque machines when a sensor fault is detected based upon multiple input speed faults.

4. The method of claim 3, further comprising coupling an engine to the input member to transfer torque to the transmission.

5. The method of claim 4, further comprising:

monitoring a signal input from a camshaft sensor of the engine; and

determining the first rotational speed of the input member using the signal input from the camshaft sensor when a speed sensor fault is detected.

6. The method of claim 4, further comprising:

monitoring signal inputs from the first sensor to determine an engine input speed; and

detecting the input speed fault based upon the engine input speed.

7. The method of claim 6, wherein the input speed fault is detected when the engine input speed is substantially static for a predetermined elapsed time period.

8. The method of claim 6, wherein the input speed fault is detected when a change in the engine input speed over a predetermined elapsed time period exceeds a predetermined threshold.

9. The method of claim 1, wherein the first and second thresholds are between about 700 and 1200 rpm during an engine idle condition.

10. The method of claim 1 wherein the first and second thresholds are about 100 rpm when the first rotational speed is greater than an engine idle speed.

11. The method of claim 1, further comprising:

using a fault counter to track detected input speed faults; and

determining a sensor fault when the fault counter reaches a predetermined number of input speed faults over a predetermined number of observations.

12. The method of claim 11, further comprising

disabling torque generation in the torque machines when a sensor fault is determined.

13. Method for monitoring a powertrain system including a transmission device operative to transmit torque between an input member, a plurality of torque generative devices, and an output member, the transmission device including a first sensor operative to monitor rotation of the input member, a second sensor operative to monitor rotation of the input member, and a plurality of sensing devices operative to monitor rotations of the torque generative devices, the first and second control modules operative to communicate therebetween, the method comprising:

signally connecting the first sensor directly to the first control module;

signally connecting the second sensor directly to the second control module;

signally connecting the plurality of sensing devices directly to the second control module;

monitoring signal inputs from the first sensor, the second sensor and the plurality of sensing devices into respectively connected ones of the first and second control modules;

determining a first rotational speed of the input member based upon the signal input from the first sensor to the first control module;

determining a second rotational speed of the input member based upon the signal input from the second sensor to the second control module;

determining rotational speeds of the torque generative devices based upon signal inputs from the plurality of sensing devices to the second control module;

calculating a third rotational speed of the input member based upon the rotational speeds of the torque generative devices;

comparing the first rotational speed to the third rotational speed and comparing the second rotational speed to the third rotational speed; and

detecting an input speed fault in one of the signal inputs from the sensing devices when the third rotational speed differs from the first rotational speed by an amount greater than a first threshold and the third rotational speed differs from the second rotational speed by an amount greater than a second threshold.

14. The method of claim 13, further comprising:

determining the signal inputs from the plurality of sensing devices are valid when one of the third rotational speed differs from the first rotational speed by an amount less than the first threshold and the third rotational speed differs from the second rotational speed by an amount less than the second threshold.

15. The method of claim 13, further comprising:

disabling torque output from the plurality of electric machines when a sensor fault is detected based upon multiple input speed faults.

16. The method of claim 15, further comprising coupling an engine to the input member to transfer torque to the transmission.

17. The method of claim 16, further comprising:

monitoring a signal input from a camshaft sensor of the engine; and

determining the first rotational speed of the input member using the signal input from the camshaft sensor when a speed sensor fault is detected.

18. The method of claim 17, further comprising:

monitoring engine input speed; and

detecting the input speed fault based upon the monitored engine input speed.

19. The method of claim 13, further comprising:

using a fault counter to track the detected input speed faults; and

determining a sensor fault when the fault counter reaches a predetermined number of input speed faults in a predetermined number of observations.

20. The method of claim 19, further comprising:

controlling torque output from the torque generative devices when a sensor fault is determined.