Fuel injection pump is the "heart" of a diesel engine. Its purpose is to establish a high pressure for the diesel fuel. The diesel engine is regularly and quantitatively supplied to the fuel injection pump and injected into the combustion chamber according to the working sequence of the engine and load changes. Once the injection pump internal leakage, and even high-pressure oil and low-carbine road connected, will cause the diesel engine start difficult, weak work until it can not be normal operation. At the same time leaked diesel into the lubricant, the lubricant diluted. Deterioration, thereby increasing the wear and tear of the parts. 1 injection pump leak diagnosis method Injection pump leak occurred, the general use of the naked eye is difficult to detect. If the engine start difficulties, the power down, there are endless lines of oil air, and sometimes automatic flameout, while the fuel injection pump housing or the bottom of the oil plane abnormal increase, you can diagnose the fuel pump internal leaks. 2 The main part of the leakage pump injection ⑴ plunger sleeve installed at the shoulder of the piston plunger pump leak Large cylinder shoulder and the upper oil pump without gasket between the two rely on the combination of fine processing to achieve seal. This is a circular, small area of ​​the sealing surface. Such as obvious signs of extrusion here, will cause a large number of diesel leaks, so that diesel engines can not work properly, and sometimes there will be low-speed rotation can barely operate, and the speed will be increased after the inhalation of air. The main reason for the extrusion marks on the shoulder of the plunger sleeve installation is that the torsional force of tightening the outlet valve seat is too large. In addition, the fluctuating stress caused by the change of the high-pressured diesel oil during work also accelerates the fatigue damage here. ⑵ Leakage between the plunger and plunger Plunger and plunger sleeve with the original very precise, the gap is only 0.002 ~ 0.003mm, both after matching and grinding, the surface roughness is particularly high precision. In use, if the diesel oil contains impurities and water, causing the plunger coupling wear or corrosion, the gap increases, the diesel leaks, and therefore can not build high pressure diesel. ⑶ plunger sleeve set screw at the location of the oil spill sleeve set a 1mm thick copper washers, which mainly from the sealing effect. If this small gasket is missing, or if it fuzz or rupture, the diesel fuel in the plunger sleeve will leak from the set screw. ⑷ leakage valve out when the oil valve seat seat and the valve seat between the large end of the copper (or nylon) gaskets. Rupture, deformation, or the end of the valve tight tighten the seat, the valve above the high-pressure oil chamber will communicate with the low pressure below, resulting in fuel injection pump can not produce high-pressure diesel. ⑸ back to the valve leakage multi-cylinder fuel pump set back to the purpose of the oil valve is to make the fuel injection pump upper body level of diesel oil to maintain about 100kPa pressure. If the oil return valve and seat wear, rust 鉵, the valve was sundries pad, or back to the phenomenon of oil, so that the plunger sleeve into the mouth of the diesel pressure drop, or the air into the fuel pump, resulting in poor or even auto-shut down the diesel engine . ⑹ Oil Leakage between Lever and Bushing When the plunger pump and bushing wear too much, or the plunger is damaged, the amount of oil drastically increases. If the drain hole is blocked, this part of the diesel fuel will flow into the fuel pump oil sump. 3 to prevent leakage of injection pump bone technical measures ⑴ strengthen the fuel supply system maintenance, the use of fully precipitated and filtered diesel, regular release fuel tank, sedimentation cup and the thickness of the filter impurities and water, and to be cleaned, To reduce the wear of precision parts.
