Traction control system for vehicle

Claim 1

A traction control system for a vehicle, comprising: a driven wheel speed calculating means for calculating a driven wheel speed of the vehicle; a vehicle speed calculating means for calculating a vehicle speed; a slip reference value calculating means for calculating a slip reference value of a driven wheel based on said vehicle speed; a comparing means for comparing said driven wheel speed and said slip reference value with each other; and an engine torque reducing means for feed-back control of the engine torque to prevent an excessive slipping of the driven wheel, when said driven wheel speed exceeds said slip reference value, wherein said traction control system further includes, a required-engine torque calculating means for calculating a required engine torque based on the driving state of the vehicle; a hunting determining means for determining a hunting of the driven wheel speed based on the number of times when said driven wheel speed has become lower than a predetermined threshold value after becoming higher than the predetermined threshold value; and an initial engine torque selecting means, which outputs said required engine torque, as an initial engine torque at the start of the feed-back control to said engine torque reducing means, when the hunting is not determined by said hunting determining means, and which outputs an engine torque smaller than said required engine torque, as the initial engine torque at the start of the feed-back control to said engine torque reducing means, when the hunting is determined by said hunting determining means.