Drive system of a utility vehicle

In a utility vehicle having a drive system including a main drive engine connected so as to drive a hydraulic pump having an outlet and an inlet respectively coupled to an inlet and an outlet of a hydraulic motor so as to conduct hydraulic fluid to and from said hydraulic motor, with said hydraulic motor being connected so as to drive at least one wheel that is in engagement with the ground and whose fluid displacement can be varied by an actuator connected with a control arrangement, where said control arrangement is connected with a rotational speed sensor arranged to detect the rotational speed of the wheel and can be operated so as to control the actuator as a function of the signals of the rotational speed sensor, the improvement comprising:

• a pressure sensor coupled to said hydraulic motor for generating a pressure signal that contains information about the difference between pressures respectively existing at said inlet and the outlet of said hydraulic motor;
• said pressure sensor being connected to said control arrangement, with said pressure signal acting to effect operation of said control arrangement such that said control arrangement causes said actuator to be controlled as a function of the pressure signal received from said pressure sensor said actuator being an electronic actuator;
• an operating arrangement for selectively sending a target velocity signal to said control arrangement;
• and said control arrangement acting in response to said target velocity signal to control said electronic actuator so that said vehicle does not operate at a velocity in excess of the target velocity.