The Function of Valve Mechanism in Car Engines and Its Types

Understanding the function of valve mechanisms and their types in cars can enhance your automotive knowledge. This can serve as additional reference when you intend to buy a car.

Below, a complete explanation of the types of valves along with their functional mechanisms will be provided. For more details, see below.

Function of Valve Mechanisms in Cars and Their Types

The main function of the valve mechanism in cars is to regulate and optimize the flow of fuel and air in the combustion chamber so that engine performance is optimal. Generally, the function of the valve mechanism is determined by the type of valve.

Based on the Type of Valve

According to their type, car engine valves are divided into two types as follows.

1. Intake Valve (In)

As the name suggests, the function of theintake valve (In) controls the flow of air and fuel in the combustion chamber. This valve adjusts the fuel and air mixture to meet the engine combustion process standards. The intake valve has a larger diameter design compared to the exhaust valve. This is done to optimize the fuel flow to the combustion chamber.

2. Exhaust Valve (Ex)

Meanwhile, the exhaust valve has the function opposite to that of the intake valve, which is to control the emission of exhaust gases from the residual combustion process in the combustion chamber. The diameter of this valve is intentionally made smaller than that of the intake valve. This is done to increase the exhaust gas pressure so that the piston is easily pushed and expels the exhaust gases.

Based on the Working Mechanism

In addition to the types above, valves in car engines are also classified based on their working mechanisms. The types are as follows.

1. OHV (Overhead Valve) Type

In this type, the valves are located above. Meanwhile, the camshaft is located below. To transmit the camshaft's motion to the valves, this valve mechanism requires the assistance of push rods. The OHV valve mechanism has several advantages, namely that the power produced is much greater and more efficient compared to other types. This occurs because the valve position is close to the spark plug and combustion chamber. Thus, the flow of air and fuel can be controlled easily and accurately.

2. SOHC (Single Overhead Camshaft) Type

In the SOHC type, there is only one camshaft, and the valve mechanism is located above the cylinder head. The SOHC type has its own advantages compared to the OHV type. It can increase engine revolutions and performance significantly. This happens because the camshaft is located above the cylinder head, making the distance between them closer. Thus, the movement of the valves becomes more responsive and easier to control. This advantage also applies to the DOHC type.

3. DOHC (Double Overhead Camshaft) Type

The DOHC type is actually an evolution of the SOHC type. In the DOHC type, there are two camshafts located above the cylinder head. These two camshafts have different roles. The first camshaft controls the intake of fuel and air, while the other camshaft controls the emission of exhaust gases. The DOHC type can be said to have a better working mechanism compared to the OHV and SOHC types. This is because DOHC can produce higher engine power and torque.

Thus, here are some functions of the car engine valve mechanism that you need to know. Considering its vital function, make sure you always pay attention to the condition of each engine valve component. Visit the nearest Daihatsu workshop when your car's engine valve has problems.

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