Apparatus and method for providing protection to electric traction motor of vehicle

• US 7,102,313 B2
• Filed: 01/10/2003
• Issued: 09/05/2006
• Est. Priority Date: 01/11/2002
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Kadota, Keiji, Shimizu, Kouichi
• Primary Examiner(s): Duda, Rina
• Assistant Examiner(s): Smith, Tyrone
• Application Number:
  US10/339,676
• Publication Number:
  US 20030151381A1
• Time in Patent Office: 1,334 Days
• Field of Search: 318461-465, 318/138, 318/254, 318/439, 318/700, 318432-434, 318/445, 180 651- 654, 701 22- 70, 477/143
• US Class Current: 318/465
• CPC Class Codes: B60K 6/448 Electrical distribution type
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60K 6/52 Driving a plurality of drive axles, e.g. four-wheel drive
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• 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 10/10 including control of change-speed gearings
• 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 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 2510/0604 Throttle position
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2710/081 Speed
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 2720/10 Longitudinal speed
• CPC Class Codes: B60W 30/146 : Speed limiting
• CPC Class Codes: B60W 30/18172 : Preventing, or responsive to skidding of wheels
• CPC Class Codes: B60W 30/184 : Preventing damage resulting from overload or excessive wear of the driveline
• CPC Class Codes: B60W 30/188 : Controlling power parameters of the driveline, e.g. determining the required power
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

An apparatus provides protection to an electric traction motor of a vehicle. The vehicle has a first powertrain and a second powertrain. The first powertrain includes an engine and it is coupled with a first set of road wheels. The second powertrain includes the electric traction motor and it is coupled with a second set of road wheels. The apparatus comprises a revolution speed sensor operatively associated with the electric traction motor. The apparatus also comprises at least one controller. The controller includes control logic for modifying operation of the vehicle in response to monitoring the revolution speed sensor to restrain the vehicle speed from increasing in such a manner as to limit revolution speed of the electric traction motor to revolution speed values below an allowable upper revolution speed limit.

Claims

1. An apparatus for providing protection to an electric traction motor of a motor vehicle having a first set of road wheels and a second set of road wheels, the apparatus comprising:

a first powertrain including an engine and being coupled with the first set of road wheels;

a second powertrain including the electric traction motor and being coupled with the second set of road wheels;

a revolution speed sensor operatively associated with the electric traction motor of the second powertrain; and

at least one controller, the controller including control logic for modifying operation of the first powertrain of the vehicle in response to monitoring the revolution speed sensor to restrain the vehicle speed from increasing in such a manner as to limit revolution speed of the electric traction motor to revolution speed values below an allowable upper revolution speed limit.

2. The apparatus as claimed in claim 1, wherein the control logic modifies operation of the vehicle to restrain the vehicle speed from increasing when revolution speed of the electric traction motor exceeds a predetermined value that is lower than the allowable upper revolution speed limit.

3. The apparatus as claimed in claim 1, wherein the control logic for modifying operation of the vehicle to restrain the vehicle speed from increasing includes:

limit criteria wherein a desired value of motor torque of the electric traction motor is limited by an upper limit of motor torque that approaches to zero as revolution speed of the electric traction motor approaches to the allowable upper revolution speed limit.

4. The apparatus as claimed in claim 1, wherein the control logic for modifying operation of the vehicle to restrain the vehicle speed from increasing includes:

determination of a torque down in output torque of the engine independently of the vehicle operator torque demand.

5. The apparatus as claimed in claim 1, wherein the first powertrain includes a transmission in a torque path between the engine and the first set of road wheels, and wherein the control logic for modifying operation of the vehicle to restrain the vehicle speed from increasing includes:

neglecting a shift up request in determining a shift command to be applied to the transmission.

6. The apparatus as claimed in claim 5, wherein the control logic for modifying operation of the vehicle to restrain the vehicle speed from increasing includes:

selecting a shift down request in determining a shift command to be applied to the transmission.

7. An electric traction motor protecting apparatus for a vehicle having a first set of road wheels and a second set of road wheels, the apparatus comprising:

a first powertrain including an engine and being coupled with the first set of road wheels;

a second powertrain coupled with the second set of road wheels and including an electric traction motor and at least one of a reduction gearing and a clutch;

a revolution speed sensor operatively associated with the electric traction motor of the second powertrain; and

at least one controller, the controller including control logic for modifying operation of the first powertrain of the vehicle in response to monitoring the revolution speed sensor to restrain the vehicle speed from increasing in such a manner as to limit revolution speed of the electric traction motor to revolution speed values below an allowable upper revolution speed limit.

8. The apparatus as claimed in claim 7, wherein the clutch of the second powertrain selectively disengages the electric traction motor from the second set of road wheels.

9. The apparatus as claimed in claim 7, wherein the reduction gearing of the second powertrain is arranged to drivingly interconnect the electric traction motor and the second set of road wheels.

10. A method for providing protection to an electric traction motor of a motor vehicle having a first powertrain and a second powertrain, the first powertrain including an engine and being coupled with a first set of road wheels, the second powertrain including the electric traction motor and being coupled with a second set of road wheels, the method comprising:

establishing a threshold revolution speed accounting for an allowable upper revolution speed limit;

monitoring a revolution speed sensor operatively associated with the electric traction motor of the second powertrain;

comparing the monitored revolution speed to the threshold revolution speed; and

modifying operation of the first powertrain of the motor vehicle in response to the comparing the monitored revolution speed to the threshold revolution speed to restrain the vehicle speed from increasing in such a manner as to limit the revolution speed of the electric traction motor to revolution speed values below the allowable upper revolution speed limit.

11. A method for providing protection to an electric traction motor of a motor vehicle having a first powertrain and a second powertrain, the first powertrain including an engine and being coupled with a first set of road wheels, the second powertrain including the electric traction motor and an electromagnetic clutch operable in response to supply of electric current to engage the motor to a second set of road wheels, the method comprising:

monitoring a revolution speed sensor operatively associated with the electric traction motor;

counting time when the monitored revolution speed stays above a predetermined revolution speed value after the supply of the electric current through the clutch has been stopped;

comparing the time counted to a predetermined time value; and

modifying operation of the motor vehicle when the time counted exceeds the predetermined time value to restrain the vehicle speed from increasing in such a manner as to limit the revolution speed of the electric traction motor to revolution speed values below the allowable upper revolution speed limit.

12. A method for providing protection to an electric traction motor of a motor vehicle having a first powertrain and a second powertrain, the first powertrain including an engine and being coupled with a first set of road wheels, the second powertrain including the electric traction motor and a clutch operable to engage the motor to a second set of road wheels for operation in 4WD mode, the method comprising:

determining whether or not the 4WD mode operation is completed;

monitoring a revolution speed sensor operatively associated with the electric traction motor;

counting time when the monitored revolution speed stays above a predetermined revolution speed value after determining that the 4WD mode has been completed;

comparing the time counted to a predetermined time value; and

modifying operation of the motor vehicle when the time counted exceeds the predetermined time value to restrain the vehicle speed from increasing in such a manner as to limit the revolution speed of the electric traction motor to revolution speed values below the allowable upper revolution speed limit.

13. An apparatus for providing protection to an electric traction motor of a motor vehicle having a first set of road wheels, and a second set of road wheels, the apparatus comprising:

a first powertrain including an engine and being coupled with the first set of road wheels;

a second powertrain including the electric traction motor and being coupled with the second set of road wheels;

means for sensing a revolution speed operatively associated with the electric traction motor of the second powertrain; and

means for modifying operation of the first powertrain of the vehicle in response to monitoring the revolution speed sensor to restrain the vehicle speed from increasing in such a manner as to limit revolution speed of the electric traction motor to revolution speed values below an allowable upper revolution speed limit.