Controller and control method for a hybrid electric vehicle powertrain

• US 20060081405A1
• Filed: 12/02/2005
• Published: 04/20/2006
• Est. Priority Date: 09/22/2003
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Mack, David, Kuang, Ming Lang, Anthony, Joseph W., Ochocinski, Christopher A.
• Granted Patent: US 7,210,546 B2
• Time in Patent Office: Days
• US Class Current: 180/65.235
• 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: B60L 2240/441 Speed
• 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 10/115 with planetary gears
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• 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 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 30/1884 Avoiding stall or overspeed of the engine
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/91 Orbital, e.g. planetary gears
• CPC Class Codes: Y10S 903/93 Conjoint control of different elements

Abstract

A parallel hybrid electric vehicle powertrain and control method wherein an internal combustion engine and an electric motor system define a split power operating mode, a generator drive mode and a parallel power mode. Provision is made, when the motor is inoperable, for preventing discharge of a battery in the electric motor system when the battery state-of-charge is low and for delivering power from the battery when the battery state-of-charge is greater than a predetermined value.

Claims

1. A method for controlling a hybrid electric vehicle powertrain having an internal combustion engine, a battery, an electric generator, an electric motor and transmission gearing, the battery, the motor and the generator being electrically coupled to define an electrical driving power source, the engine defining a mechanical power source, the generator being drivably connected to a first element of the gearing and the engine being drivably connected to a second element of the gearing;

the method comprising the steps of;

determining desired input torque, vehicle speed and the state-of-charge of the battery;

determining whether the state-of-charge is less than a predetermined high value above which charging of the battery is not allowable;

determining whether the state-of-charge is greater than a predetermined target value;

operating the powertrain using both the engine and the electrical power source when the state-of-charge is less than the high value and greater than the target value; and

operating the powertrain using solely the generator and the battery as a power source with the engine off when the state-of-charge is greater than the high value.

2. The method set forth in claim 1, wherein the powertrain is operated using both the engine and the electrical power source when the vehicle speed is less than a predetermined value and the state-of-charge is less than the target value.

3. The method set forth in claim 2, wherein the powertrain is operated using solely the generator and the battery as a power source when the state-of-charge is higher than the high value.

4. The method set forth in claim 1, wherein the powertrain is operated using both the engine and the electrical power source when the vehicle speed is greater than a maximum value and the state-of-charge is less than the target value and using solely the engine as a power source when the state-of-charge is greater than the target value;

the generator being braked to condition the powertrain for operation with the engine as a sole power source.

5. The method set forth in claim 1, wherein the powertrain is operated using both the engine and the electrical power source when the vehicle speed is less than the maximum value and greater than the minimum value and the state-of-charge is less than the target value.

6. The method set forth in claim 4, wherein the powertrain is operated using the engine as a sole power source when the state-of-charge is greater than the target value.

7. The method set forth in claim 6, wherein the powertrain is operated using solely the generator and the battery as a power source when the state-of-charge is greater than the high value.

8. The method set forth in claim 5 wherein, during operation using both the engine and the electrical power source, the desired engine torque is a function, at least in part, of driver torque demand and battery charging power.

9. The method set forth in claim 6 wherein, during operation using the engine as a sole power source, the desired engine torque is a function, at least in part, of driver torque demand.

10. The method set forth in claim 7 wherein, during operation using solely the generator and the battery as a power source, the desired generator torque is a function, at least in part, of driver torque demand.