Hybrid electric vehicle control strategy while traveling in reverse

• US 6,603,215 B2
• Filed: 05/24/2001
• Issued: 08/05/2003
• Est. Priority Date: 05/24/2001
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Patil, Prabhakar B, Kuang, Ming Lang, McCarthy, James Paul
• Primary Examiner(s): Waks, Joseph
• Application Number:
  US09/865,100
• Publication Number:
  US 20030001391A1
• Time in Patent Office: 803 Days
• Field of Search: 290/40.C, 290/40.B, 290/45, 180/65.2, 475/5
• US Class Current: 290/40.00C
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 15/2063 for creeping
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• 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 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• 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 2510/081 Speed
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 30/18036 Reversing
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility
• CPC Class Codes: Y10S 903/903 : having energy storing means, e.g. battery, capacitor

Abstract

A method for reverse drive mode operation of a hybrid electric vehicle includes determining an output power of the internal combustion engine, determining a power circulation loss between a generator and a motor, determining a benefit power based on the difference between the output power of the internal combustion engine and the power circulation loss, and stopping operation of the internal combustion engine during the reverse drive mode operation of the vehicle if the benefit power is less than a predetermined threshold power value.

Claims

1. A method for reverse drive mode operation of a hybrid electric vehicle, the hybrid electric vehicle having a traction motor and an operating internal combustion engine and operating generator mechanically coupled via a power transmission device, the method comprising:

determining an output power of the internal combustion engine;

determining a power circulation loss between the generator and the motor;

determining a benefit power based on the difference between the output power of the internal combustion engine and the power circulation loss; and

stopping operation of the internal combustion engine during the reverse drive mode operation of the vehicle if the benefit power is less than a predetermined threshold power value.

2. The method according to claim 1, wherein if the benefit power is greater than or equal to the predetermined threshold power value, the method further comprises:

determining a driver torque request at the motor;

determining a generator torque reflected at the motor;

summing the driver torque request and the generator torque reflected at the motor;

comparing the sum of the driver torque request and the generator torque reflected at the motor to a maximum motor torque;

determining a new generator torque request if the sum of the driver torque request and the generator torque reflected at the motor is greater than the maximum motor torque, the new generator torque request being based at least in part on a difference between a maximum motor torque and the driver torque request at the motor; and

determining a new motor torque request if the sum of the driver torque request and the generator torque reflected at the motor is less than or equal to the maximum motor torque, the new motor torque request being based at least in part on a sum of the driver torque request at the motor and a requested generator torque reflected at the motor.

3. The method according to claim 2, further comprising:

comparing the new generator torque request to a generator torque request minimum; and

stopping operation of the internal combustion engine if the new generator torque request is less than the generator torque request minimum.

4. The method according to claim 2, further comprising:

comparing the new generator torque request to a generator torque request minimum;

calculating a generator speed based at least on a speed of the internal combustion engine and a speed of the vehicle;

comparing the calculated generator speed to a maximum generator speed; and

stopping operation of the internal combustion engine if the calculated generator speed is greater than the maximum generator speed.

5. The method according to claim 4, further comprising the step of determining the new traction motor torque request if the calculated generator speed is less than or equal to the maximum generator speed.