Traction control system

摘要

A brake system for a vehicle having a traction control or anti-spin function for controlling wheel slip on differentially driven wheels of a vehicle. The system includes left and right fluid pressure operated brake mechanisms associated with left and right driven wheels of the vehicle. First and second brake valves control the communication of fluid pressure to the left and right brake mechanisms. In normal operation, an operator actuatable treadle concurrently operates both valves to simultaneously apply fluid pressure to the brake mechanisms as a function of treadle depression. Each brake valve includes a pilot pressure operated section for actuating a main fluid control section. Wheel speed sensors associated with the left and right driven wheels continuously monitor the rotational speed of the wheels. When a slip condition is detected, a control unit connected to the wheel sensors activates one of two pulse width modulated valves to produce a pilot pressure in a pilot pressure chamber of the brake valve associated with the faster rotating wheel. The communication of pilot pressure to the brake valve causes actuation of the brake mechanism thereby applying braking torque to the faster rotating wheel to reduce its wheel speed. Engine torque is thus transferred via the differential to the other wheel.