Types of valve mechanism in car engines
The valve mechanism on a car engine is a series of engine components that function to adjust the valve opening/closing to suit the needs of the engine in each cylinder.
This valve mechanism has various components such as camshaft, rocker arm, rocker shaft, valve lifter, pushrod, intake and exhaust valves, valve spring, etc. The components used in this valve mechanism are very dependent on the type of valve mechanism used in the engine.
So what are the types of valve mechanisms that exist in car engines today? Here are three types of valve mechanisms in car engines that we know.
1. Over Head valve (OHV)
The first type of valve mechanism is the Over Head Valve (OHV). Over Head Valve is a valve mechanism where the valve is mounted on the cylinder head while the camshaft is placed inside the engine cylinder block.
A push rod equipped with a valve lifter is installed to move the valve to open and close in part between the camshaft and the rocker-arm. Thus, when the camshaft lube rotates and pushes the valve lifter along with the push rod, the rocker arm will push the valve so that the valve will open.
The Over Head Valve type valve mechanism has construction and components that are quite complicated. Because of the impact of the valve opening and closing process, which is less responsive. Also, the engine performance is not good at high rpm. As a result, this OHV model engine is not suitable for use in cars that require high acceleration and speed.
2. Single Over Head Camshaft (SOHC)
The second type of valve mechanism is the Single Over Head Camshaft (SOHC). Single Over Head Camshaft is a valve mechanism with one camshaft, which is installed together with the intake and exhaust valves on the cylinder head.
So, in the engine cylinder head with a Single Over Head Camshaft mechanism, we will find one (1) camshaft with a series of intake and exhaust valves.
All cylinders in the engine with a SOHC valve mechanism are served only by one (1) camshaft. Each cylinder has two valves, namely the intake valve, which functions to suck the air and fuel mixture into the combustion chamber. The exhaust valves serve as a place to release the exhaust gases from combustion to the exhaust manifold.
The engine with a Single Over Head Camshaft valve mechanism has better acceleration and power performance than the OHV type.
Read Also3. Double Over Head Camshaft (DOHC)
The last type of valve mechanism is the Double Over Head Camshaft (DOHC). Double Over Head Camshaft is a valve mechanism with two camshafts installed to serve the valve opening and closing in each valve system.
One camshaft is used to service the intake valve only, and the other camshaft is used to service the exhaust valve only.
That way, the number of valves in each cylinder can increase engine power and performance. Therefore, in DOHC engines, we often find one cylinder engine using four valves (two intake valves and two exhaust valves). So, if the engine is four cylinders, then we will find 16 valves on the engine.
The engine with a Double Over Head Camshaft valve mechanism has better acceleration and power performance than the two previous types (OHV and SOHC).