What are the Functions of Piston Rings and Piston Pins in a Diesel Generator

In a diesel generator, the piston ring groove is surrounded by a certain elastic metal open ring. This metal ring is called the piston ring. Piston ring is one of the key components of the diesel generator, its performance directly affects the quality and reliability of the diesel generator.

According to the different uses of piston rings, piston rings are categorized into gas rings and oil rings.

The main role of the gas rings is to form a sealed combustion chamber space with the piston, cylinder head and cylinder liner to prevent the high temperature and high pressure gases in the combustion chamber from flowing into the crankcase from the piston gap, as well as the cylinder wall.

The main role of the oil ring is to ensure that the oil is evenly distributed on the inner wall of the cylinder liner, preventing the oil from entering the combustion chamber. If the oil enters the combustion chamber, the diesel generator will burn the oil, and blue smoke will come out of the exhaust pipe, and it will also increase the carbon deposits in the exhaust valve and combustion chamber and increase the amount of oil.

Piston rings are prone to severe wear, diminished elasticity, internal gumming and damage during long-term use.

The structure of a piston ring is mainly based on the shape and cross-section of the opening. The shapes of the openings are usually straight, slanted and trapezoidal. These three kinds of opening piston rings have their own advantages and disadvantages, but currently the most commonly used are straight and oblique piston rings. According to the cross-section state of the rings, they are generally categorized into rectangular, twisted, conical, barrel-faced and trapezoidal rings. Rectangular rings are easy to process, have good thermal conductivity, and are widely used in various piston rings.

According to the different structure of the oil ring, it can be generally divided into ordinary oil ring, spring expansion ring and combined steel plate oil ring. Spring-expanded oil rings and ordinary oil rings are widely used among these three types of oil rings.

Piston pins are usually made of low carbon steel or low carbon alloy steel. The surface is carburized and quenched for high hardness and improved wear resistance. Maintaining internal toughness is favorable to withstand and impact loads.

Piston pins are generally made into hollow short round tubes. The outer circle has high machining accuracy and finish, and grooves and gaps are not allowed. The inner hole is usually cylindrical. According to the bearing capacity of the piston pin, part of the bore is formed into a conical structure.

The main function of the piston pin is to connect the piston and the connecting rod, and transfer the gas pressure at the top of the piston and the inertia force of the reciprocating motion of the piston group to the connecting rod.

At present, there are two combinations of piston pins, piston pin seats, and connecting rod small end bushing holes. One is a semi floating piston pin, and the other is a fully floating piston pin, which is the piston pin and pin. The seat hole is a transition (or gap), and there is a gap with the small end bushing hole of the connecting rod. At present, high-speed diesel engines mostly use fully floating piston pins, as this type of matching piston pin rotates slowly, which can ensure uniform wear along the circumference.

We hope the above content is helpful to you. If you are interested in diesel generator sets, please feel free to contact us via email at: dingbo@dieselgeneratortech.com .