TRACTION CONTROL FOR A HYBRID ELECTRIC POWERTRAIN

• US 20150298678A1
• Filed: 04/22/2014
• Published: 10/22/2015
• Est. Priority Date: 04/22/2014
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: YU, HAI, FODOR, MICHAEL G.
• Granted Patent: US 11,097,711 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• 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 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 2050/0049 Signal offset
• CPC Class Codes: B60W 2050/0056 Low-pass filters
• CPC Class Codes: B60W 2510/083 Torque
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2510/246 Temperature
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2520/26 Wheel slip
• CPC Class Codes: B60W 2552/40 Coefficient of friction
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 2710/248 Current for loading or unloading
• CPC Class Codes: B60W 2720/30 Wheel torque
• CPC Class Codes: B60W 30/18172 Preventing, or responsive to skidding of wheels
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

An electric machine and internal combustion engine are coordinated to provide traction control for an automotive vehicle. A propulsive torque limit is set by a controller during a loss of traction. When the machine torque limit is greater than the propulsive torque limit, the engine is pulled down. When the machine torque is less than the propulsive torque limit, the engine is pulled up. The controller coordinates the pulled up engine with the machine such that the engine is subordinated to the machine.

Claims

1. A method of controlling an automotive powertrain comprising:

controlling an engine and electric machine based on a propulsive torque limit that is a function of a loss of traction;

stopping the engine when a machine torque limit exceeds the propulsive limit;

restarting the engine when the propulsive limit exceeds a future machine torque limit.

2. The method of claim 1 wherein the future machine torque limit is a function of a future battery discharge power limit and a predicted vehicle speed.

3. The method of claim 2 wherein the future discharge power limit is a function of a present battery state of charge, a present battery temperature, an average variance rate of the battery state of charge, and an average variance rate of the battery temperature.

4. The method of claim 2 wherein the predicted vehicle speed is a function of a present vehicle speed and a present vehicle acceleration rate.

5. The method of claim 1 wherein the step of controlling the engine and electric machine based on the propulsive torque limit is conditioned upon a vehicle speed being less than a speed threshold and an estimated road friction condition being less than a road friction threshold.

6. The method of claim 1 wherein the machine torque limit is a positive torque limit reduced by a positive torque offset.

7. A method of controlling an automotive powertrain comprising:

controlling an engine and electric machine based on a propulsive torque limit that is a function of a loss of traction;

limiting an engine torque while using the engine to supplement the machine when the propulsive limit exceeds a machine torque limit.

8. The method of claim 7 wherein the engine torque is limited to the propulsive torque limit filtered through a low pass filter, reduced by a positive torque limit of the machine, and increased by an engine torque offset margin.

9. The method of claim 7 wherein the machine torque limit is limited to the propulsive torque limit reduced by the propulsive torque limit filtered through a low pass filter, increased by a positive torque limit of the machine, and reduced by an engine torque offset margin.

10. The method of claim 7 wherein the step of controlling the engine and electric machine based on the propulsive torque limit is conditioned upon a vehicle speed being less than a speed threshold and an estimated road friction condition being less than a road friction threshold.

11. A method of controlling an automotive powertrain comprising:

controlling an engine and electric machine based on a propulsive torque limit that is a function of a loss of traction;

commanding the machine to operate as a generator while increasing an engine torque limit by an engine torque offset margin.

12. The method of claim 11 wherein a machine torque limit is limited to the propulsive torque limit reduced by the propulsive torque limit filtered through a low pass filter, increased by a positive torque limit of the machine, and reduced by an engine torque offset margin.

13. The method of claim 11 wherein the step of controlling the engine and electric machine based on the propulsive torque limit is conditioned upon a vehicle speed being less than a speed threshold and an estimated road friction condition being less than a road friction threshold.