Diesel generator set in high load operation, exhaust smoke, black smoke generation process generally thought that when the diesel engine load, sprayed into the combustion chamber of the fuel increased, the combustion chamber temperature and higher, coupled with the uneven formation of diesel engine mixture characteristics, which will cause the combustion chamber in local areas of air shortage of combustion, fuel decomposition in the absence of oxygen at high temperatures, the polymerization of carbon smoke (carbon black). Carbon soot is not pure carbon, but a polymer, the main component is carbon (85% or more), but also contains a small amount of oxygen, hydrogen and ash, and its composition varies with the load of the diesel engine. The black smoke through the filter to collect the carbon smoke under the electron microscope observation, you can see the large carbon smoke particles in the diameter of 0.05mm or so. Diesel engine combustion of high-temperature cracking reaction is inevitable, especially in the space of mixed combustion of diesel engines, high-temperature gas surrounded by liquid oil droplets, resulting in the most favorable conditions for cracking reaction, the combustion process of high-speed photography confirmed, in the upper stop point around will appear a large amount of black smoke, but in general, soot can be found in the subsequent combustion of air and complete combustion, so that the exhaust without black smoke. But if the cylinder air is not enough, the mixing process is slow, then due to expansion and negative cylinder temperature drop, the carbon can not be burned and aggregated into soot. The formation of carbon soot so that incomplete combustion, diesel engine economy decline, the exhaust temperature rise, black smoke, combustion chamber surface carbon, and the load can no longer progress. Carbon will also cause the piston ring or piston stuck, valve bite and other failures, so do not promise that the diesel engine in a long time under the state of overload work.