Abstract: A method for controlling activation of a power source of a hybrid electric vehicle. A hybrid electric vehicle has first and second power sources connected to a motor. The motor is connected to a transmission adapted to drive a vehicle wheel. The method includes comparing a vehicle speed value to first and second threshold values. If the vehicle speed value is less than the first threshold value, then the method determines whether a vehicle brake is released. If the vehicle speed value is greater than the first threshold value and less than the second threshold value, the method determines whether additional acceleration is demanded. The power source is activated if additional power is demanded or if the vehicle brake has been released. The power source is deactivated if the brake is engaged or if additional power is not demanded.

Abstract: A method for controlling activation of a power source of a hybrid electric vehicle. A hybrid electric vehicle has first and second power sources connected to a motor. The motor is connected to a transmission adapted to drive a vehicle wheel. The method includes comparing a vehicle speed value to first and second threshold values. If the vehicle speed value is less than the first threshold value, then the method determines whether a vehicle brake is released. If the vehicle speed value is greater than the first threshold value and less than the second threshold value, the method determines whether additional acceleration is demanded. The power source is activated if additional power is demanded or if the vehicle brake has been released. The power source is deactivated if the brake is engaged or if additional power is not demanded.

Abstract: A method for operating a hybrid vehicle when starting a power source. The method includes initiating a start sequence that includes driving the power source at a target speed, determining a speed adjustment value based on an amount of vehicle acceleration requested by the driver, adjusting the target speed, and modifying output of the electrical machine to maintain the target speed.

Abstract: A method for controlling a wheel drive system of a hybrid electric vehicle when starting a power source. The hybrid electric vehicle includes first and second power sources, a motor, and a power transfer unit adapted to drive a vehicle wheel. The method includes determining whether the first power source is to be started, determining whether a level of torque requested by a vehicle operator is greater than a threshold value, maintaining a current gear ratio if the threshold value is exceeded, and providing a target level of torque to the power transfer unit.