Piston group: equipment and device
The piston group is a piston and a group of sealing rings. It also includes a piston pin and fasteners. It is worth considering the purpose of this mechanism.
Due to it, the gas pressure is sensed andis transmitted through the connecting rod to the crankshaft. Also thanks to such a mechanism as the piston group, the piston cylinder cavity is compacted. Thus, it will be protected from excessive contact with oil and gas in the crankcase. This function is of great importance for good engine performance. About that, in what technical condition it is, judge by sealing ability. For example, engine engines do not allow oil consumption to be more than three percent of fuel consumption.
The piston group carries out its work also insevere climatic conditions. That is why the details of this mechanism have a high thermal tension, and this is taken into account when the material and construction are selected for them. Their elements are usually developed by manufacturers, considering the type of engines and purpose (transport, stationary, diesel, shaped, etc.). However, the overall device still remains the same. So, we should consider what the piston group is made from.
The trunk portion (guide) is also calledpiston skirt. It has tides on the inside, holes for the piston pin are drilled in them. The lower edge of the skirt is often used as a technological base for the processing of the piston. It is equipped with a bead for this purpose. In addition, the walls of the skirt still perceive the forces of lateral pressure, and this increases their friction against the cylinder walls and increases the heating of the cylinder and the piston.
The piston head carries piston rings and hasbottom. The lower groove has drainage holes, through which the lubricating oil flows so that it does not accidentally enter the combustion chamber. Its bottom is one of the chamber walls. It perceives a significant pressure of gases. The bottom itself can be flat, concave, convex, or figured. Again, its shape is chosen when considering the type of engine, as well as the combustion chamber.
It is impossible not to mention such a mechanism ascylinder-piston group. The main defects of the cylinder blocks are cracks, chips and wear. These faults are installed after a thorough inspection, crimping and measurement of the cylinder. In this process, the unit needs to be fitted with a head or a cast-iron plate (a rubber gasket is mandatory). In general, this group is characterized by heat-resistant steel and oil cooling, which is carried out due to the circulating general lubrication system of the main diesel engine. If you provide a good care mechanism and quality oil, you can easily extend the life of the pistons and cylinders.
And one more mechanism is the crank-piston group. The piston is cast and aluminum. The outer surface has a very complex shape. The piston pin is hollow and steel, it rotates freely in the connecting rod bushing and piston bosses. And the piston rings are made of cast iron. And, of course, the connecting rod is forged and steel. In its upper head there is a bushing made of a mixture of steel and bronze, which positively affects the work of the whole group.