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

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;
• and
• at least one controller, the controller including 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.

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;
• comparing the monitored revolution speed to the threshold revolution speed;
• and
• modifying operation 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.

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.

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.