What is the function of valves?
1 Answers
The function of valves is specifically responsible for introducing air into the engine and expelling exhaust gases after combustion. In terms of engine structure, they are divided into intake valves and exhaust valves. The intake valve's role is to draw air into the engine to mix with fuel for combustion; the exhaust valve's role is to expel the burned exhaust gases and dissipate heat. Here is additional information: 1. Composition: A valve consists of a valve head and a stem. The shape of the valve head can be flat, spherical, or trumpet-shaped, among others. Flat valve heads are simple in structure, easy to manufacture, have a small heat absorption area, and are lightweight, making them suitable for both intake and exhaust valves. The valve stem is cylindrical and continuously moves back and forth in the valve guide, requiring its surface to be heat-treated and polished. The shape of the valve stem end depends on the method of fixing the valve spring, with the common structure using two half-lock pieces to secure the spring seat. The valve stem end has a groove for installing the lock pieces, while some use a lock pin for fixation, with a hole at the end for installing the lock pin. 2. Current Status: To improve intake and exhaust efficiency, multi-valve technology is now widely used, commonly featuring four valves per cylinder (though some designs have three or five valves per cylinder, following the same principle, such as the Audi A6's engine). For a four-cylinder engine, this totals 16 valves, often indicated as "16V" in automotive specifications. This multi-valve structure easily forms a compact combustion chamber, with the fuel injector positioned centrally, allowing the air-fuel mixture to burn more quickly and uniformly. The weight and opening of each valve are appropriately reduced, enabling faster opening and closing speeds.
