What is a valve on a car?

Answer 1

A valve is exactly what it means its a passageway that opens and closes at a certain time. With this it is what opens and lets air in to give the spark oxygen to ignite the fuel therefore pushing the piston down to make your engine run. There is another valve that opens at the opposite time, when the piston is returning into its up cycle, to allow the spent gases to escape and go out the exhaust. It is all timed by either a timing chain or a timing belt. They have to be installed at a specific spot on the crankshaft and the cam gear so that this timing is obtained. The cam which is attached to the cam gear which is what spins to open the valves at the right time. Your car has to have at least 2 valves per each cylinder so it has the intake side and exhaust side but can have even more. Audi/VW has some engines with 5 per cylinder. The only type of engine that doesnt require valves to operate would be a Wankel or rotary engine which is what they use in the Mazda RX-7/RX-8.