Abstract: A method of controlling a vehicle drive system is provided for a vehicle having an internal combustion engine, free-wheeling steerable front wheels, driven rear wheels, an infinitely variable transmission (IVT) transmitting torque from the engine to the rear wheels, and a control unit for controlling the IVT as a function of sensed parameters and supplying a speed command to the IVT for commanding a speed of the rear wheels. The method includes sensing a steering angle of the front wheels, sensing a front wheel speed, sensing a rear wheel speed, generating a corrected estimated vehicle speed as a function of the front wheel speed and the sensed steering angle, and increasing the speed command in response to a comparison between the corrected estimated vehicle speed and the rear wheel speed. The infinitely variable transmission is preferably embodied by a hybrid electric drive system.

Abstract: A vehicle electric drive system has an internal combustion engine which drives an electric generator. The generator powers a motor which drives the wheels. The system has operator controls including a speed control member movable from a zero speed position to a high speed position, an FNR direction control member having forward, neutral and reverse positions. The system also includes a wheel speed sensor and an electronic control unit. Upon startup, the control unit senses the position of the direction control member, senses wheel speed, and senses position of the speed control member. The controller prevents vehicle operation if the direction control member is not in its neutral position, or the sensed wheel speed is not close to zero, or the speed control member is not near its zero speed position. The controller permits vehicle operation if the direction control member is in its neutral position, and the sensed wheel speed is close to zero, and the speed control member is near its zero speed position.