Moottoriventtiileitä

Moottoriventtiileitä are essential components in internal combustion engines, controlling the flow of air-fuel mixture into the cylinder and exhaust gases out of it. There are typically two main types of valves in each cylinder: intake valves and exhaust valves.

Intake valves are responsible for opening to allow the compressed air-fuel mixture into the combustion chamber during the intake stroke. They then close and remain shut during the compression and power strokes. Exhaust valves, on the other hand, open to release the burnt gases from the cylinder after the power stroke, during the exhaust stroke. They then close to seal the combustion chamber for the next cycle.

The operation of these valves is precisely timed by the engine's camshaft, which is driven by the crankshaft, usually via a timing belt or chain. The camshaft has lobes that push on valve lifters or rocker arms, which in turn open the valves against spring pressure. When the lobe rotates away, the spring closes the valve.

The materials used for moottoriventtiileitä are critical due to the high temperatures and pressures they experience. Intake valves are typically made of steel alloys, while exhaust valves, facing even more extreme conditions, are often made of more robust materials like Nimonic alloys or are coated to resist heat and corrosion. Valve seats, the surfaces against which the valves seal, are also hardened to ensure a tight seal and longevity. Wear and proper sealing of the valves are crucial for engine performance, efficiency, and emissions control.