SYSTEM AND METHOD TO PREVENT DRIVELINE FLOAT IN LASH REGION

• US 20180326969A1
• Filed: 07/20/2018
• Published: 11/15/2018
• Est. Priority Date: 11/08/2016
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: JOHRI, Rajit, KUANG, Ming Lang, CONNOLLY, Francis Thomas, NEFCY, Bernard D., ZHAO, Yanan, SYED, Fazal Urrahman
• Granted Patent: US 10,640,102 B2
• Time in Patent Office: Days
• CPC Class Codes: B60K 2006/4825 Electric machine connected or connectable to gearbox input shaft
• CPC Class Codes: B60K 2006/4833 Step up or reduction gearing driving generator, e.g. to operate generator in most efficient speed range
• CPC Class Codes: B60K 6/387 Actuated clutches, i.e. clutches engaged or disengaged by electric, hydraulic or mechanical actuating means
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60W 10/023 Fluid clutches
• 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 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 20/11 using model predictive control [MPC] strategies, i.e. control methods based on models predicting performance utilising navigation and traffic information in the control strategy B60W20/12
• CPC Class Codes: B60W 2030/18081 With torque flow from driveshaft to engine, i.e. engine being driven by vehicle
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/106 Rate of change
• CPC Class Codes: B60W 2710/027 Clutch torque
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 2710/1011 Input shaft speed, e.g. turbine speed
• CPC Class Codes: B60W 2710/1022 Input torque
• CPC Class Codes: F16H 2057/128 using axial positioning of gear wheel with addendum modification on gear width, i.e. backlash is compensated by axial positioning of a slightly conical gear wheel
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/93 Conjoint control of different elements

Abstract

A vehicle includes an engine and an electric machine coupled to a gearbox through a torque converter. The vehicle includes a controller programmed to command an engine torque and an electric machine torque to achieve a predetermined positive torque at the input of the torque converter when a driver demand torque at the torque converter input decreases to fall within a range between the predetermined positive torque and a predetermined negative torque.

Claims

1. A vehicle comprising:

an engine and an electric machine coupled to a gearbox through a torque converter; and

a controller programmed to, in response to a driver demand torque at an input of the torque converter decreasing to fall within a range between a predetermined positive torque and a predetermined negative torque, command an engine torque and an electric machine torque to achieve the predetermined positive torque at the input of the torque converter.

2. The vehicle of claim 1, wherein the controller is further programmed to, in response to the driver demand torque at the input decreasing below the predetermined negative torque, command the engine torque and the electric machine torque to achieve the driver demand torque.

3. The vehicle of claim 1, wherein the controller is further programmed to, in response to the driver demand torque at the input increasing to fall within the range between the predetermined positive torque and the predetermined negative torque, command the engine torque and the electric machine torque to achieve the predetermined negative torque.

4. The vehicle of claim 1, wherein the controller is further programmed to, in response to the driver demand torque at the input increasing to exceed the predetermined positive torque, command the engine torque and the electric machine torque to achieve the driver demand torque.

5. The vehicle of claim 1, wherein the predetermined positive torque is an impeller stall torque of the torque converter.

6. The vehicle of claim 5, wherein the controller is further programmed to estimate the impeller stall torque based on a model of the torque converter.

7. The vehicle of claim 1, wherein the predetermined positive torque is a predetermined value that is equal to an impeller stall torque when a turbine speed of the torque converter is greater than a minimum impeller stall speed.

8. The vehicle of claim 7, wherein predetermined positive torque is a maximum of the impeller stall torque and a predetermined positive torque value.

9. A method comprising:

operating, by a controller, an engine and an electric machine that are coupled to a gearbox through a torque converter to cause a torque of the torque converter to achieve a predetermined positive torque at an input of the torque converter in response to a driver demand torque at the torque converter decreasing to fall within a range between the predetermined positive torque and a predetermined negative torque.

10. The method of claim 9 further comprising operating, by the controller, the engine and the electric machine to cause the torque to achieve the driver demand torque in response to the driver demand torque being less than the predetermined negative torque.

11. The method of claim 9 further comprising operating, by the controller, the engine and the electric machine to cause the electric machine to achieve the predetermined negative torque in response to the driver demand torque increasing to fall within the range between the predetermined positive torque and the predetermined negative torque.

12. The method of claim 9 further comprising operating, by the controller, the engine and the electric machine to cause the torque to achieve the driver demand torque in response to the driver demand torque being greater than the predetermined positive torque.

13. The method of claim 9 further comprising estimating, by the controller, the predetermined positive torque as an impeller stall torque during a drive cycle based on a model of the torque converter.

14. A powertrain control system comprising:

an engine and an electric machine coupled to a gearbox through a torque converter; and

a controller programmed to, responsive to a driver demand torque at the torque converter decreasing to fall within a range between an impeller stall torque of the torque converter and a predetermined negative torque, command the engine and the electric machine to cause a torque at the torque converter to be the impeller stall torque.

15. The powertrain control system of claim 14, wherein the controller is further programmed to, responsive to the driver demand torque falling below the predetermined negative torque, command the engine and the electric machine to cause the torque to achieve the driver demand torque.

16. The powertrain control system of claim 14, wherein the controller is further programmed to, responsive to the driver demand torque increasing to fall between the impeller stall torque and the predetermined negative torque, command the engine and the electric machine to cause the torque to achieve the predetermined negative torque.

17. The powertrain control system of claim 14, wherein the controller is further programmed to, responsive to the driver demand torque increasing to exceed the impeller stall torque, command the engine and the electric machine to cause the torque to achieve the driver demand torque.

18. The powertrain control system of claim 14, wherein the controller is further programmed to estimate the impeller stall torque during a drive cycle based on a model of the torque converter.

19. The powertrain control system of claim 14, wherein the controller is further programmed to, responsive to a turbine speed of the torque converter being greater than a minimum impeller stall speed, limit the impeller stall torque to be greater than a predetermined positive torque threshold.