traction control

A traction control system (TCS), on current production vehicles, are typically (but not necessarily) electro-hydraulic systems designed to prevent loss of traction (and therefore the control of the vehicle) when excessive throttle or steering is applied by the driver. Although similar to Electronic Stability Control systems, Traction Control systems do not have the same goal.

The intervention can consist of any, or all, of the following:
  • Retard or suppress the spark to one or more cylinders
  • Reduce fuel supply to one or more cylinders
  • Brake one or more wheels
  • Close the throttle, if the vehicle is fitted with drive by wire throttle.
  • In turbo-charged vehicles, the boost control solenoid can be actuated to reduce boost and therefore engine power.
Typically, the Traction Control system shares the brake actuator and the wheel speed sensors with the anti-lock braking system.

History of Traction Control

The predecessor of modern electronic traction control systems can be found in high-torque, high-power rear-wheel drive cars as a limited slip differential, known as Positraction. As this system worked mechanically to transfer power to the individual rear wheel slipping the least, it still allowed some wheel spin to occur.

Mercedes-Benz pioneered and introduced electronic traction control to market. In 1971, the Buick division of GM introduced MaxTrac, which used an early computer system to detect rear wheel spin and modulate engine power to those wheels to provide the most traction. A Buick-exclusive at the time, it was an option on all fullsize models, including the Riviera, Estate Wagon, Electra 225, Centurion, and popular LeSabre family sedan.

Use of traction control

  • In road cars: Traction Control has traditionally been a safety feature in high-performance cars, which would otherwise need very sensitive throttle input to keep them from spinning when accelerating, especially in wet or snowy conditions. In recent years, Traction Control systems have become widely available in non-performance cars, minivans, and light trucks.
  • In race cars: Traction Control is used as a performance enhancement, allowing maximum traction under acceleration without wheel spin. When accelerating out of turn, it keeps the tires at the optimum slip angle.
  • In off road vehicles: Traction Control is used instead or in addition to the mechanical limited slip or locking differential. It is often implemented with an electronic limited slip differential, as well as other computerized controls of the engine and transmission. The spinning wheel is slowed down with short applications of brakes, diverting more torque to the non-spinning wheel. This form of traction control has an advantage over a locking differential as steering and control of a vehicle is easier, so the system can be continuously enabled. It also creates less stress on the drivetrain, which is particularly important to the vehicles with an independent suspension that is generally weaker compared to solid axles. On the other hand, only half of the available torque will be applied to a wheel with traction, compared to a locked differential, and handling is less predictable.
It is widely thought that TC removes some skill and control from the driver. As such it is unpopular with many motorsports fans. Some motorsports series have given up trying to outlaw TC. With current state of technology, it is possible to implement TC as a part of software in ECU, and as such it is very hard to detect by scrutineers. Very effective yet small units are also available through a company in the US, Davis Technologies [1], that allow the driver to remove the traction control system after an event if desired. In Formula One, an effort to ban TC has led to the change of rules for 2008: every car must have a standard (but custom mappable) ECU, issued by FIA, which is relatively basic and does not have TC capabilities.

Traction control in cornering

Traction control is not just used for moving a vehicle from stationary without slippage. During hard maneuvers in a front wheel drive car there is a point where the wheels cannot both steer and drive the car at the same time without losing traction. With traction control, it's less likely for this loss of control to occur. There is a limit though, when the tires lose grip. The car will not corner as sharply as indicated by the front wheels, this is Understeer. In some front wheel drive cars, Traction Control can induce Lift-off oversteer due to its throttle retarding capabilities. This can keep some cars stable in long maneuvers. In rear wheel drive cars, traction control can prevent Oversteer

All car manufacturers strongly point out in vehicle manuals that the Traction Control system is not to be taken for granted and that its presence should not encourage dangerous driving or situations beyond the driver's control.

See also

External links

Vehicles are non-living means of transport. They are most often man-made (e.g. bicycles, cars, motorcycles, trains, ships, and aircraft), although some other means of transport which are not made by man can also be called vehicles; examples include icebergs and floating tree trunks.
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Traction refers to the friction between a drive member and the surface it moves upon, where the friction is used to provide motion.

For the purposes of driving a wheeled vehicle, high friction is generally desired, as it provides a more positive connection between the
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Electronic Stability Control (ESC) is the generic term for systems designed to improve a vehicle's handling, particularly at the limits where the driver might lose control of the vehicle.
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A cylinder is the central working part of a reciprocating engine, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block
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An anti-lock braking system (ABS) (translated from German, Antiblockiersystem) is a system on motor vehicles which prevents the wheels from locking while braking. The purpose of this is to allow the driver to maintain steering control under heavy braking and, in some
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A limited slip differential (LSD) is a modified or derived type of differential gear arrangement that allows for some difference in rotational velocity of the output shafts, but does not allow the difference in speed to increase beyond a preset amount.
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A limited slip differential (LSD) is a modified or derived type of differential gear arrangement that allows for some difference in rotational velocity of the output shafts, but does not allow the difference in speed to increase beyond a preset amount.
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Buick Motor Division

Division of GM
Founded 1903
Headquarters Detroit, Michigan, USA

Industry Automotive
Products Entry-level luxury vehicles
Parent General Motors
Slogan Drive Beautiful
Website www.buick.
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slip angle is the angle between a rolling wheel's actual direction of travel and the direction towards which it is pointing (i.e., the angle of the vector sum of wheel translational velocity and sideslip velocity ).
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Off Roading is a term for driving a specialized vehicle on unpaved roads, such as sand, gravel, riverbeds, mud, snow, rocks and other natural terrain.

Off-road vehicle


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A locking differential or locker is a variation on the standard automotive differential. A locking differential provides increased traction compared to a standard, or "open" differential by disallowing wheel speed differentiation between two wheels on the same axle under
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Independent suspension is a broad term for any automobile suspension system that allows each wheel on the same axle to move vertically (i.e. reacting to a bump in the road) independently of each other.
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beam axle is a suspension system, also called a solid axle, in which one set of wheels is connected laterally by a single beam or shaft. A live axle is a type of beam axle in which the shaft (or shafts, since live axles, while connected to move as a single unit, are seldom
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Automobile racing (also known as auto racing, motor racing, or car racing) is a sport involving racing automobiles. Auto racing began in 1895,[1] and is now one of the world's most popular sports.
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Computer software is a general term used to describe a collection of computer programs, procedures and documentation that perform some task on a computer system. [1]
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An engine control unit (ECU) is an electronic control unit which controls various aspects of an internal combustion engine's operation. The simplest ECUs control only the quantity of fuel injected into each cylinder each engine cycle.
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Category Single seaters
Country or region International
Inaugural season 1950[1]
Drivers 22
Teams 11
Engine suppliers 6
Drivers' champion Fernando Alonso
Official website formula1.
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This article or section contains information about scheduled or expected future events.
It may contain tentative information; the content may change as the event approaches and more information becomes available.
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Understeer is a term for a car handling condition during cornering in which the circular path of the vehicle's motion is of a markedly greater diameter than the circle indicated by the direction its wheels are pointed.
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Lift-off oversteer (also known as snap-oversteer, trailing-throttle oversteer, throttle off oversteer, or lift-throttle oversteer) is a form of oversteer in an automobile that occurs when the vertical load on the tires shifts from the rear to the front
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Oversteer is a phenomenon that can occur in an automobile which is attempting to turn. The car is said to oversteer when the rear wheels do not track behind the front wheels but instead slide out toward the outside of the turn. Oversteer can throw the car into a spin.
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Automobile safety is the avoidance of automobile accidents or the minimization of harmful effects of accidents, in particular as pertaining to human life and health. Numerous safety features have been built into cars for years, some for the safety of car's occupants only, some for
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