Controller and control method for a hybrid electric vehicle powertrain

• US 7,210,546 B2
• Filed: 12/02/2005
• Issued: 05/01/2007
• Est. Priority Date: 09/22/2003
• Status: Expired due to Fees

• 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.
• Primary Examiner(s): VANAMAN, FRANK BENNETT
• Application Number:
  US11/293,750
• Publication Number:
  US 20060081405A1
• Time in Patent Office: 515 Days
• Field of Search: 180/65.1, 180/65.2, 180/65.3, 180/65.4, 903/925, 903/943
• US Class Current: 180/65.265
• 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 to define separate power flow paths through the gearing to vehicle traction wheels;

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 less than the target value; and

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

operating the powertrain 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, the battery and the motor 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, the battery and the motor as a power source.

2. 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 to define separate power flow paths through the gearing to vehicle traction wheels;

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 less than the target value; and

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

wherein, during operation using both the engine and the electrical power source, a desired engine torque is a function of at least in part, of driver torque demand, and a desired engine speed is a function, at least in part, of vehicle speed and battery charging power.

3. 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 to define separate power flow paths through the gearing to vehicle traction wheels;

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 less than the target value; and

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

wherein, during operation of the powertrain using the engine, the battery and the motor as a sole power source, a desired engine torque is a function, at least in part, of driver torque demand, and a desired engine speed is a function, at least in part, of vehicle speed.

4. 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 to define separate power flow paths through the gearing to vehicle traction wheels;

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 less than the target value; and

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

wherein, during operation of the powertrain using the engine, the battery and the motor as a power source, a desired generator torque is a function, at least in part, of driver torque demand.

5. 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 to define separate power flow paths through the gearing to vehicle traction wheels;

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 less than the target value;

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

operating the powertrain in a parallel drive mode using solely the engine, the battery and the motor.