Throttle

throttle

Valve for regulating the supply of a fluid (as steam) to an engine, especially the valve controlling the volume of vaporized fuel delivered to the cylinders of an internal-combustion engine. In an automobile engine, gasoline is held in a chamber above the carburetor. Air flows down through the throat of the carburetor, past the throttle valve, and into the intake manifold. A throat is formed by the reduced diameter, and acceleration of the air through this smaller passage causes a decrease in pressure related to the amount of air flowing. This decrease in throat pressure results in fuel flow from the jet into the airstream. Any increase in airflow caused by change in engine speed or throttle position increases the pressure differential acting on the fuel and causes more fuel to flow. See also venturi tube.

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throttle

To cause something to slow down or speed up. See CPU throttling and throttled transfer.

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throttle

1. any device that controls the quantity of fuel or fuel and air mixture entering an engine

2. an informal or dialect word for throat

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throttle [′thräd·əl]

(mechanical engineering)

throttle valve

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Throttle 

a device whose cross section is considerably smaller than that of the pipeline leading to it. A throttle regulates the flow rate and changes other parameters (temperature, humidity, and superheating) of a working body flowing in a closed channel.

Throttles are mounted in front of a steam turbine to control loading by throttling the steam; in high-pressure steam lines they are used to reduce pressure at the point where the steam enters a low-pressure steam line (for example, in heating systems). They are also used in compressors and blowers to decrease the pressure of the gas at the intake and in refrigerators to expand the compressed gas in order to cool it. One type of throttle is an accelerator, which controls the supply of the fuel mixture to the cylinders of internal-combustion engines.