We all know that the engine is by inhaling the mixture of air and fuel into the combustion within the engine cylinder explosion to generate power, and then discharge the combustion exhaust gas,
while in charge of the agency is the valve four-stroke engine intake and exhaust.
Valve is one of the very important parts of the interior of the engine, a valve is divided into an intake valve (intake valve) and the exhaust valve (exhaust valve), it looks like the shape of the horn. The intake valve is responsible for air entering the intake manifold and the fuel mixture (direct injection supply) within the cylinder into the cylinder within the control, while the exhaust valve is responsible within the cylinder after the combustion exhaust gas cylinder additional control. The previous engine each cylinder has only one intake valve and one exhaust valve, so the design is relatively simple and low cost, the low-speed response of the vehicle is good, but less efficient at high speed, and later in order to enhance the intake and exhaust efficiency, improve vehicle performance, today most of the engines are multi-valve design, the most common is a 4-valve per cylinder design, four-cylinder engine, for example, 4-valve per cylinder 16-valve four cylinder is, is often in see in magazines or on the network "16V".
The operation of the valve is through the belt of the crankshaft to the camshaft or metal chain driven camshaft, and then driven by the camshaft and protruding parts valve open Next, the operation of the intake and exhaust, As regards the operation of closing are handed The valve spring is responsible. The nowadays mostly valve spring is mostly cylindrical spiral-type spring, and its role is to rely on the spring tension to open steam valve quickly returned to the closed position, and to prevent the valve in the gap during the movement of the engine due to the inertial forces to ensure valve in the closed state close fit, but also to prevent the destruction valve in the beating and vibration sealing.
Since the valve and the valve spring must work in adverse and harsh environments, especially the valve is directly in contact with the high-temperature gas, so on the material must have sufficient rigidity and heat resistance. Most of today's valve using a special heat-resistant alloy the JIS SUH3 burned into hardened Advanced heat-resistant alloy steel JIS SUH36 (21-4N), STELLITE cobalt-chromium-tungsten alloy steel material made. Valve springs are mostly made of Central carbon chrome vanadium wire or silicon-chromium wire, so that the spring has sufficient rigidity and fatigue strength, and to withstand the frequent compression load and maintain a suitable elastic force.