Method for monitoring an auxiliary pump for a hybrid powertrain

• US 8,068,966 B2
• Filed: 10/10/2008
• Issued: 11/29/2011
• Est. Priority Date: 11/03/2007
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG, Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Original Assignee: Bayerische Motoren Werke AG, GM Global Technology Operations LLC (General Motors Company), Daimler AG (Mercedes-Benz Group AG), Chrysler LLC (Stellantis NV)
• Inventors: Naqvi, Ali K, Trierweiler, Rebecca, Naqi, Syed, Martini, Ryan D, Wu, Peter E.
• Primary Examiner(s): Elchanti; Hussein A
• Application Number:
  US12/249,563
• Publication Number:
  US 20090118954A1
• Time in Patent Office: 1,145 Days
• Field of Search: 701/51, 701 60- 61
• US Class Current: 701/60
• 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 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/485 Temperature
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• 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 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 2050/0006 Digital architecture hierarchy
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/0671 Engine manifold pressure
• CPC Class Codes: B60W 2510/107 Temperature
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2510/246 Temperature
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2555/20 : Ambient conditions, e.g. wind or rain
• CPC Class Codes: B60W 50/029 : Adapting to failures or work around with other constraints, e.g. circumvention by avoiding use of failed parts
• CPC Class Codes: B60W 50/04 : Monitoring the functioning of the control system
• CPC Class Codes: F16H 2037/0873 : with switching, e.g. to change ranges
• CPC Class Codes: F16H 2061/1208 : with diagnostic check cycles; Monitoring of failures
• CPC Class Codes: F16H 2061/122 : Avoiding failures by using redundant parts
• CPC Class Codes: F16H 2061/1244 : Keeping the current state
• CPC Class Codes: F16H 2061/1264 : Hydraulic parts of the controller, e.g. a sticking valve or clogged channel
• CPC Class Codes: F16H 61/0031 : using auxiliary pumps, e.g. pump driven by a different power source than the engine
• CPC Class Codes: F16H 61/12 : Detecting malfunction or potential malfunction, e.g. fail safe in control of hydrostatic gearing F16H61/4192; Circumventing or fixing failures
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles

Abstract

A powertrain system includes a hybrid transmission coupled to an engine and an auxiliary hydraulic pump. The auxiliary hydraulic pump is commanded to operate at a predetermined speed only when enable criteria are met. An engine-off state is inhibited based upon a difference between a commanded speed and a monitored operating speed of the auxiliary hydraulic pump.

Claims

1. A method for monitoring a powertrain system including a hybrid transmission coupled to an engine selectively operative in engine-on and engine-off states during ongoing operation of the powertrain system and including an auxiliary hydraulic pump selectively operative to pump hydraulic fluid in a hydraulic circuit of the hybrid transmission, the method comprising:

monitoring a plurality of enable criteria;

commanding the auxiliary hydraulic pump to operate at a predetermined speed only when all the enable criteria are met;

monitoring an operating speed of the auxiliary hydraulic pump;

comparing the commanded speed and the monitored operating speed of the auxiliary hydraulic pump; and

inhibiting the engine-off state based upon a difference between the commanded speed and the monitored operating speed of the auxiliary hydraulic pump.

2. The method of claim 1, wherein the enable criteria comprise the engine in an engine-off state, the powertrain system in a key-on state, the auxiliary hydraulic pump in an enabled state, the auxiliary hydraulic pump in an available state, and a temperature of the hydraulic fluid within a predetermined range.

3. The method of claim 2, wherein the enable criteria comprising the temperature of the hydraulic fluid within a predetermined range includes a minimum temperature threshold and a maximum temperature threshold.

4. The method of claim 3, wherein the minimum temperature threshold and the maximum temperature threshold each include temperature hysteresis.

5. The method of claim 1, comprising inhibiting the engine-off state when the difference between the commanded speed and the monitored operating speed of the auxiliary hydraulic pump exceeds a predetermined threshold.

6. The method of claim 5, further comprising identifying a speed performance fault when the difference between the commanded speed and the monitored operating speed of the auxiliary hydraulic pump exceeds the predetermined threshold.

7. The method of claim 6, monitoring the speed performance faults, and detecting an auxiliary pump fault when a predetermined number of speed performance faults have occurred.

8. The method of claim 7, further comprising inhibiting engine operation in the engine-off state when an auxiliary pump fault has been detected.

9. The method of claim 1, further comprising permitting the engine-off state after a predetermined elapsed time subsequent to inhibiting the engine-off state.

10. The method of claim 9, further comprising inhibiting the engine-off state until a key-on event after a predetermined number of cycles of permitting and inhibiting the engine-off state.

11. A method for monitoring a powertrain system including a hybrid transmission connected to an engine selectively operative in engine-on and engine-off states during ongoing operation of the powertrain system and including an auxiliary hydraulic pump selectively operative to pump hydraulic fluid in the hybrid transmission, the method comprising:

monitoring the engine state;

commanding the auxiliary hydraulic pump to operate at a predetermined speed when the engine is operated at the engine-off state;

monitoring hydraulic pressure in the hybrid transmission;

determining an operating speed of the auxiliary hydraulic pump based upon the monitored hydraulic pressure;

comparing the commanded speed and the determined operating speed of the auxiliary hydraulic pump; and

inhibiting the engine-off state when the a difference between the commanded speed and the determined operating speed of the auxiliary hydraulic pump exceeds a predetermined threshold.

12. The method of claim 11, comprising determining the predetermined threshold based upon a temperature of the hydraulic fluid.

13. The method of claim 11, further comprising permitting the engine-off state after an elapsed time period.