What is the function of the engine valve train?

[CarlosMarie]

The function of the engine valve train is to open and close the intake and exhaust valves of each cylinder in a timely manner according to the working cycle and firing order requirements of each cylinder in the engine. This allows fresh charge to enter the cylinder promptly and exhaust gases to be expelled from the cylinder in time, while ensuring the sealing of the combustion chamber during the compression and expansion strokes. For gasoline engines, the fresh charge refers to the mixture of gasoline and air, while for diesel engines, it is pure air. The requirements for the valve train are that its structural parameters and configuration should help reduce intake and exhaust resistance. Additionally, the timing and duration of valve opening should be appropriate to ensure that both intake and exhaust processes are as complete as possible, thereby achieving greater power, torque, and emission performance.

[OAnderson]

I've been driving for almost twenty years, and the valve train is a pretty core component. It manages the opening and closing of the engine's intake and exhaust valves—when the engine runs, the valves must open on time to let fresh air and fuel into the cylinders, then close for combustion and exhaust. Without it, the engine wouldn't start at all, and idle would be rough with sluggish acceleration. The most common valve train issues I've encountered are stuck valves or worn-out springs, leading to unstable idle, doubled fuel consumption, and even stalling or breakdowns in severe cases. Maintenance is straightforward, though—just regularly check valve clearance and camshaft wear. Using high-quality oil can protect the parts and extend their lifespan. Modern cars often feature smart adjustment tech to optimize this system. Still, it's best to pay attention to unusual noises or power changes while driving to catch issues early and save big on repairs.

[RuthFitz]

As a car enthusiast, I believe the valve train directly impacts engine performance. It precisely controls the valve opening/closing timing and lift, determining the intake volume and airflow efficiency—more intake means more complete combustion and increased power output. Performance cars often feature dual overhead camshaft designs or variable valve timing systems that adjust valve operation at different RPMs to optimize torque and horsepower, resulting in smoother acceleration and reduced fuel consumption. If valve train issues occur, such as camshaft wear preventing valves from opening fully, engine response becomes sluggish with weak power output, and emissions exceed standards harming the environment. During modifications, tuning valve timing can significantly enhance overall performance—never overlook regular maintenance to ensure efficient operation.

[EdwardRose]

During my time as a mechanic, I've dealt with numerous valve train malfunctions. Its core function is to control the opening and closing timing of intake and exhaust valves to ensure proper gas exchange operation. Common issues include excessive valve clearance or broken springs causing improper valve closure—resulting in engine shaking at idle, abnormal noises, power loss, and increased fuel consumption. Another problem is camshaft wear altering valve lift and affecting efficiency. Car owners can perform self-checks by listening for knocking sounds during cold starts or checking trouble codes. For maintenance, replacing aged components and engine oil is key—low-cost upkeep prevents major issues. Don't wait until the engine is ruined to regret neglecting it.