Throttle

2006-08-07T01:07:58Z

72.151.20.162:

In an [[engine]], the '''throttle''' is the mechanism by which the engine's power is increased or decreased. Throttle may refer to both the part inside the engine which directly regulates the fuel flow, or the human controls (pedal, lever, electronic) that the operator uses to indirectly control an engine's power.

== Internal combustion engines ==

[[Image:USPatent6518683.png|right|150px]]

In an [[internal combustion engine]], the throttle is a valve that directly regulates the amount of air entering the engine, and indirectly controls the amount of fuel, and thus regulates the engine speed. In a vehicle, the control that human operators use may be referred to as a 'gas pedal' or 'accelerator'.

The throttle is typically a [[butterfly valve]]. In a [[fuel injection|fuel-injected]] engine, the throttle valve is housed in the [[throttle body]]. In a carbureted engine, it is found in the [[carburetor]]. The butterfly valve in a fuel-injected throttle body has one or more holes in it to allow the engine air when idling.

When a throttle is [[wide open throttle|wide open]], the intake manifold is usually at ambient atmospheric pressure. When the throttle is partially closed, a [[manifold vacuum]] develops as the intake drops below ambient pressure.

Usually the throttle valve is mechanically linked with the throttle pedal or lever. In vehicles with [[electronic throttle control]], the throttle valve is electronically controlled, which allows the [[Engine Control Unit|ECU]] greater possibilties in reducing air emissions.

[[Category:Engine technology]]
[[Category:Auto parts]]

Traction Control

2006-08-07T00:58:21Z

72.151.20.162:

'''Traction Control''' (TC) systems, 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 the [[Electronic Stability Control]] systems, the Traction Control systems don't have the same goal as them.

On road cars, TC is often packaged with Anti-lock Brakes (ABS), because the same sensors that detect wheels stopped or decelerating faster than other wheels also detects them spinning faster than other wheels or accelerating faster than a preprogramed amount.

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|drive by wire]] throttle.

The brake actuator, and the wheel speed sensors, are the same as that used for [[Anti-Lock Brakes ABS|anti-lock braking systems]].

==Use of Traction Control==
* ''In road cars:'' Traction Control is used mainly as 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. It is also used in off-road vehicles to enhance traction on loose surfaces.
* ''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 tyres at the optimum slip angle.

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. In Formula One, an effort to ban TC has lead to the change of rules for 2008: every car must have a standard ECU, issued by FIA, which is relatively basic and does not have TC capabilities.

==See Also==
* [[Electronic Stability Control]]
* [[Anti-Lock Brakes ABS|Anti-Lock Brakes]]

==External Links==
* [http://www.thatsracin.com/mld/thatsracin/archives/3617715.htm Motorsport officials deny the use of traction control is common]
* [http://www.circletrack.com/techarticles/general/139_0211_traction_control/index.html Motorsport site claiming its use is rife].

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Throttle

Traction Control