Throttles, chokes, dampers, and valves all restrict fluid flow. Aside from specific terminology/usage in internal combustion engines, are these really interchangeable terms, or do they have some specific meaning? Perhaps choke and throttle only apply to internal combustion engines and have no standard meaning outside that context? Damper might then be a special case of valve that applies to gases?

Dictionary definitions are not tremendously helpful. From Wiktionary:

Choke: 1. A control on a carburetor to adjust the air/fuel mixture when the engine is cold.

Throttle: 1. A valve that regulates the supply of fuel-air mixture to an internal combustion engine and thus controls its speed; a similar valve that controls the air supply to an engine.

Damper: 1. Something that damps or checks: A valve or movable plate in the flue or other part of a stove, furnace, etc., used to check or regulate the draught of air.

Valve: 1. A device that controls the flow of a gas or fluid through a pipe. 2. A device that admits fuel and air into the cylinder of an internal combustion engine, or one that allows combustion gases to exit.

  • $\begingroup$ Add nozzle to your list with convergent or divergent... $\endgroup$
    – Solar Mike
    Sep 4, 2020 at 17:27
  • $\begingroup$ And "snubber" to restrict flow. $\endgroup$ Sep 4, 2020 at 20:20

1 Answer 1


Choke is usually just applied to starting fuel/air mix regulation for ICE engines, as far as I'm aware.

Throttle is used to actively manage fluid flow while a device is operating.

Dampers typically only refer to means of controlling air/exhaust flow in non-ICE, like power plants or HVAC systems. As in your definition a damper is usually just a movable plate or plates (ie louver).

Valve is just a general term for any sort of flow control device that is usually comprised of an inlet, outlet and means of limiting or preventing flow. Myriad configurations available.

  • $\begingroup$ So if there is an exhaust fan fixed with a semi-permanent non-movable obstruction to restrict flow, is it still appropriate to call it a damper or there a better term? $\endgroup$
    – PProteus
    Sep 4, 2020 at 16:15
  • $\begingroup$ Your definitions imply a dynamic feature. A non-movable obstruction is just an obstruction to me. Probably a proper HVAC term for it. But a non-permanent semi-movable obstruction on the other hand... $\endgroup$
    – jko
    Sep 4, 2020 at 16:53
  • $\begingroup$ @PProteus In my brief history of reviewing HVAC drawings for manufacturing facilities, "dampers" are adjustable flow restrictions while "louvers" are static devices. "Damper" tends to get used as a catch all term in my experience. $\endgroup$
    – J. Ari
    Sep 5, 2020 at 13:49
  • $\begingroup$ @ J. Ari What about a "baffle"? $\endgroup$
    – PProteus
    Sep 8, 2020 at 11:05

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