What is the cause of piston breakage?

Causes of piston fracture roughly the following points:

1. The top of the piston coke serious. Coking at the top of the piston causes the top of the piston to overheat and generate high temperatures. When the local high temperature exceeds the melting point of the material, the top of the piston will be fused to form a melting hole.

2. Piston ring cemented or broken. Piston ring cementation or fracture will lead to the piston ring can not be close fit with the cylinder wall, the top of the piston heat can not be passed in time, but also guide the high-temperature gas channeling, the result of the piston top and piston ring groove parts due to overheating and ablation.

3. Uneven oil supply. Diesel engine cylinder fuel supply and fuel supply time and if uneven, will make some of the cylinder combustion process deteriorates, the formation of coke or serious afterburner, diesel combustion heat can not be used for work, leaving part of the cylinder piston top temperature Too high, resulting in thermal fatigue and burning materials.

4. Nozzle working bad. When the nozzle appears drip, secondary injection, poor atomization, etc., the piston top oil at the local temperature is too high, thermal stress increases, resulting in ablation.

5. Engine knocking. Engine work, the top of the piston to withstand explosive combustion cycle of mechanical shock, the instantaneous impact force up to 7MPa, the direct impact on the piston above the impact of up to 100kN. If the engine knock, the impact will be doubled. Piston top in the thermal stress and periodic combustion explosive force, resulting in thermal fatigue and mechanical fatigue, and ultimately lead to burning and cracking. The main reason for the engine detonation is the fuel supply time or ignition time too early, too much coke in the cylinder, the compression ratio is too high, the hot piston on the top of the formation of hot spots caused by premature combustion, the octane number of gasoline used is too low.

6. Oil cooling nozzle is clogged. Some high-power engine body is equipped with oil cooling nozzle, by injecting oil to the piston cavity to help cool the heat. If the oil cooling nozzle is blocked, the piston will accumulate heat, but also easily lead to burning the top of the piston.

7. Long engine overloaded speeding operation, or poor engine cooling. Long-term piston subjected to thermal stress and mechanical stress, easy to fatigue ablation.

8. Piston quality failed. If the piston casting porosity, porosity, micro-cracks, slag and other defects, under the action of high temperature and pressure, these pores, loose, microcracks will become a source of fatigue and lead to fatigue damage; slag in the piston first melt, causing the piston Burn.

9. Often thunderstorms, high-speed engine running at high speed, the temperature is too high.