What is the function of valves?
3 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.
The valve in the engine acts like a gate, controlling the airflow in and out of the cylinder. After driving my car for several years, I've realized that the valve's most critical function is to allow fresh air to mix with fuel for combustion, generating power to push the piston, and then expelling the exhaust gases. If the valve gets stuck or doesn't close properly, the engine will shake, lose power, fuel consumption will skyrocket, or it may even stall—especially frustrating in traffic jams. Regular maintenance shouldn't be overlooked; periodic carbon deposit cleaning can extend its lifespan. Simply put, it controls the engine's breathing. Without it, the car won't move, just like a person struggling without oxygen. I once had a valve issue that cost me hundreds to fix, so now I pay more attention to abnormal engine sounds and get them checked promptly.
The valves in the engine are essentially intake and exhaust gates, controlling the air-fuel mixture intake and exhaust processes. After years of repairing cars, common issues I've seen are excessive carbon buildup on valves or weak springs, leading to poor sealing—resulting in the engine struggling, with reduced power and increased fuel consumption. Their core functions are twofold: opening the intake passage to let the air-fuel mixture in and opening the exhaust passage to clear out the waste gases. This cycle is essential for generating power, and neither can be neglected. I recommend car owners check their valve condition every 10,000 kilometers—don't wait for a major failure to fix it, as costs will double and compromise driving safety. The inspection is simple: listen for unusual noises or test drive at low speeds. Proper maintenance keeps your car running stronger.
