Traction Control System: Outline

The traction control system (TCS) is a system that controls engine output in accordance with road surface and vehicle travel conditions, so that the driving force stays within the friction limits. By doing this, it improves start/acceleration performance and safety.
In general, the tire's driving force reaches its maximum at a certain slip ratio, and then decreases as the slip ratio increases. To determine the slip ratio, the TCS takes the driven wheel speed as the vehicle speed, and compares this speed with the drive wheel speed.
During straight travel, the TCS controls engine output so that the slip ratio is near the value where maximum driving force is obtained. And during turning, the TCS deduces the turn radius from driven wheel inner/outer speed difference, and controls the slip ratio to a value lower than that during straight travel, to provide sufficient lateral force. In this way, TCS improves driving stability.