Camshaft is a tool used in the machine to run the poppet valve. He consists of a cylindrical rod. Cam opens the valve by pressing it, or the mechanism, as they rotate.
The relationship between the rotation of the camshaft with the crankshaft rotation is very important. Since the valves control the flow of fuel intake and expenditure, they must be opened and closed at the right time during the step piston. For this reason, the camshaft is connected to the crankshaft either directly (via the gear mechanism) or indirectly through a chain called "a chain".
In a two-cycle engine that uses a camshaft, each valve is opened once for each rotation of the crankshaft in this engine, the camshaft rotates at the same speed as the crankshaft.
In a four-stroke engine the valves are opened only half as often, thus, two full rotations of the crankshaft occur for each rotation of the camshaft.
Sliding friction between the front of the cam follower depending on the amount of friction. To reduce wear, the cam and the follower has a hard surface, and modern lubricant oil contains ingredients that specifically reduce sliding friction. Lobe (ears) of the camshaft usually tapered, resulting follower or valve lifter rotates slightly in each pressure, and make the wear components. Usually the front of the cam and follower are designed to wear together, so when one is worn out then they should be replaced to prevent excessive wear.
