The piston works under high temperature, high pressure, high speed and poor lubrication. The piston directly contacts with high-temperature gas, and the instantaneous temperature can reach more than 2500K. Therefore, the piston is seriously heated and the heat dissipation condition is very poor, so the temperature of the piston is very high when it is working, and the top is up to 600-700K, and the temperature distribution is very uneven; The top of the piston bears great gas pressure, especially the pressure of the work stroke, which is as high as 3~5MPa for gasoline engines and as high as 6~9MPa for diesel engines. This makes the piston impact and bear the effect of side pressure; The piston moves back and forth at a high speed (8~12m/s) in the cylinder, and the speed is constantly changing, which generates a large inertial force and makes the piston subject to a large additional load. When the piston works under such harsh conditions, it will deform and accelerate wear, generate additional load and thermal stress, and be subject to chemical corrosion of gas.

The main points for assembling the piston connecting rod set of diesel generator are as follows:

1, Press the connecting rod copper sleeve. When installing the connecting rod copper sleeve, it is better to use a press or vice instead of a hammer; The oil hole or oil groove on the copper sleeve shall be aligned with the oil hole on the connecting rod to ensure its lubrication

2, Assemble the piston and connecting rod. When assembling pistons and connecting rods, pay attention to their relative positions and directions.

3, Install the piston pin skillfully. The piston pin and pin hole are interference fit. During installation, the piston shall be evenly heated to 90 ℃~100 ℃ by placing it in water or engine oil. After taking it out, the pull rod shall be placed at an appropriate position between the piston pin seat holes, and then the piston pin coated with engine oil shall be installed into the piston pin hole and the connecting rod copper sleeve in the given direction

4, Installation of piston rings. When installing the piston ring, pay attention to the position and order of each ring.