A firefighter involved in the rescue told reporters that after they arrived at the scene, the exploded off-road vehicle was burning and there was a pool of blood near the vehicle. "According to the surrounding citizens, the man who was injured after the incident was taken to the hospital, and the injury was not light. There was a lot of blood. "
On the morning of August 3rd 10: 40, Weibo, the official of Suzhou Dongguan Police Station, announced that an explosion accident caused by suspected vehicle spontaneous combustion occurred at the east gate of Ke Tong City Garden Community in Dongguan at about 9: 50 on August 3rd17. At present, the person involved has been sent to the hospital for treatment by 120, and the incident is under further investigation.
The so-called deflagration is because the pressure and temperature of the gas are too high, the combustible mixture burns itself without ignition, and the flame spreads outward at a speed several times higher than that of normal combustion, producing a sharp knocking sound. This will overheat the engine, reduce power, increase fuel consumption and damage parts. Slight deflagration is allowed, but strong deflagration is very harmful to the engine.
cause
Once the engine explodes, it will do great harm, which will cause the deformation and damage of the moving parts of the engine, such as cylinder wall, piston, piston ring, valve, connecting rod and connecting rod bearing. The specific reasons are usually as follows:
1) Too much carbon deposit.
Excessive carbon deposition in the engine combustion chamber makes its volume relatively smaller, which leads to a corresponding increase in compression ratio. The heat storage and thermal conductivity of carbon deposits make the combustible mixture burn ahead of time due to intense heat, at the same time, it will reduce the vortex intensity of the mixture at the end of compression, prolong the combustion time and increase the tendency of spontaneous combustion, so it is easy to induce deflagration.
2) The engine is overheated.
When the engine is in a state of high power, overload or low-grade and high-speed continuous driving for a long time, especially in hot summer, the external temperature is high and the heat dissipation of parts is poor, which is easy to cause the engine to overheat. When the overheating fault is serious and cannot be improved in time, the combustible mixture will be preheated when it enters the combustion chamber, causing the local mixture temperature to be too high, reaching the ignition point ahead of time, and burning itself before the fuel can not be ignited normally, thus causing deflagration;
3) Improper use of fuel.
The lower the brand of gasoline, the worse the antiknock performance. If the gasoline is stored for too long or poorly sealed, the octane number will naturally decrease and the antiknock performance will become worse. If misused, it is easy to make the mixture burn incompletely, and the mixture burned first will partially expand, compressing the remaining unburned mixture, making it reach the spontaneous combustion temperature, and suddenly all of it will catch fire, leading to high-pressure explosive combustion;
4) Engine crank chamber leaks air.
The self-tightening spring of crankshaft oil seal lip of two-stroke engine falls off or fails; The aging of oil seal rubber becomes stiff, which makes the spring self-tightening force unable to seal; During engine maintenance, the oil seal is scratched or bruised; The carburetor adapter (intake pipe or intermediate gasket) is not tightened, etc. The air leakage caused by these components will dilute the mixture, thus destroying normal combustion and easily causing premature combustion and deflagration.
5) Early ignition angle:
In order to make the piston get power immediately after the compression top dead center, it is usually ignited before the piston reaches the top dead center (because it takes some time from ignition to complete combustion). But premature ignition will make most of the oil and gas burn while the piston is still in the compression stroke. At this time, the unburned oil and gas will bear great pressure and spontaneously ignite, resulting in deflagration.