Valve Train System

The engine valve train opens and closes the intake and exhaust valves of each cylinder on time according to the requirements of the working cycle and ignition sequence of each cylinder of the engine, sucks the fresh charge into the cylinder, and discharges the exhaust gas after combustion from the cylinder device. The valve train is very important to the engine. If the valve train is properly designed, the efficiency of the engine will be higher and the fuel economy will be good. This article mainly introduces the parts and maintenance directions of the internal combustion forklift engine valve train.

Parts of the valve train

The internal combustion forklift engine mainly adopts the overhead valve type air distribution system. Parts of the valve train include the valve, valve guide, valve spring, spring seat, lock plate, rocker arm, push rod, tappet, and camshaft. This article mainly introduces the functions of the camshaft, valve, and rocker arm.

What is a camshaft?

A camshaft is a component of a piston engine. The function of an engine camshaft is to control the opening and closing of the valve. The camshaft has high requirements in terms of strength and support, and its material is generally high-quality alloy steel or alloy steel. Since the law of valve motion is related to the power and running characteristics of an engine, the design of the camshaft occupies a very important position in the design process of the engine.

What is a valve?

The valve is the component in the compressor used to control the flow of gas into and out of the cylinder. It is mainly composed of a valve seat, valve plate, spring, and lift limiter. The lift or closure between the valve plate and the valve seat determines the size and tightness of the gas passage. The spring is mainly used to push the valve plate to close, and it can also reduce the impact of the valve plate and the lift limiter when it is opened. The lift limiter can limit the lift of the valve plate and can support the spring.

What is a rocker arm?

The function of the rocker arm is to change the direction of the reciprocating motion of the ejector rod to the air valve. The rocker arm shaft is installed in the rocker arm seat, and the rocker arm seat is fixed on the cylinder head. In order to reduce weight and maintain sufficient rigidity, its section is often made into an "I" shape. There are various rocker arm types, for example, stamped steel rocker arm, roller tipped rocker arm, full roller rocker arm, and so on.

Valve train repair options

As an important part of the internal combustion engine, the valve train controls the intake and exhaust process of the engine. The rationality of its design is directly related to the power performance, economic performance, emission performance, reliability, and durability of the internal combustion engine. As the mileage of the gas truck increases, the working performance will gradually decrease until it affects the working condition of the whole vehicle. The detection and maintenance of common faults in the valve train become more and more important.

When the engine is working, the common damage to the valve set parts are groove and widening of the working surface of the valve and valve seat; spots and depressions after burning; wear and bending of valve stem; loose fit between the valve stem and valve guide; free length of valve spring Shortening, loss of elasticity and deformation, or even breaking, etc.