what ia a valve?

Answer 1

what car?
what year?

Answer 2

generally an intake valve opens to allow air or an air fuel mixture to enter a cylinder of an engine, it then seals closed to allow compression, followed by ignition, and a power stroke, then an exhaust valve opens to allow the burnt gases to escape the cylinder and into the exhaust system. The exhaust valve will then seal and The process then starts over again

for performance reasons, racers like to use larger valves so air and exhaust can move more freely. Also advertised is how many valves a car has, as using multiple intake and sometimes exhaust valves implies higher performance.

Answer 3

It all depends in which concept you are using it.

There is a valve in your tyre to stop air escaping but allowing air to be put in.

There are valves in your engine which allow the gasses to enter the cylinder and power the engine, then remove the waste gas.

There are valves in the windscreen washer system that allow water to run one way.

The thermostat, controlling the temperature of water around the engine is a valve.

There are many so you need to be a little more specific.

Good luck hope this helps.

Answer 4

A device that regulates gas or liquid flow by opening, closing or obstructing its passage.

Answer 5

http://auto.howstuffworks.com/engine4.htm
see if this helps.