What are the components of the valve train?
2 Answers
The valve train consists of a camshaft, tappet, pushrod, rocker arm, valve spring, valve, and valve guide. Its function is to open and close the intake and exhaust valves in a timely manner according to the working process and sequence of each cylinder of the diesel engine, ensuring the timely supply of sufficient fresh air and exhaust gas. When the piston is in the compression and expansion strokes, it ensures the sealing of the valves. There are two types of valve trains: overhead and side-mounted. Overhead diesel engines are widely used in small tractors. The overhead valve train includes a drive group composed of timing gears and camshafts, a valve transmission group composed of tappets, pushrods, rocker arms, and rocker arm shafts, and a valve group composed of valves, valve springs, guides, spring seats, and locking plates.
I find the valve train quite fascinating—it's like the respiratory system of an engine, mainly consisting of valves, valve springs, valve guides, and valve seats, along with components like rocker arms, pushrods, and the camshaft. The camshaft drives the rocker arms back and forth, pushing the valves to open and close, controlling the airflow in and out. The valve springs ensure the valves snap back quickly, while the guides and seats help with precise positioning. Back when I drove an older car, I experienced unstable idling due to worn-out springs, so regular inspection of these parts is crucial to avoid affecting overall performance. Valve train designs vary—modern cars often use dual overhead camshafts (DOHC) for better efficiency—but fundamentally, the components remain similar.
