The Fuel Injection System Research Of 240/275E Diesel Engine

The failure rate of national diesel locomotive apparently increased after speeding. Fuel injection system has the following main problems: the weak system reliability, shorter maintenance period, high cost of repairing, etc. In order to meet the requirements of fuel injection system on reliability and performance, and also to follow the national railway's rapid development, the physical design of 240/275E diesel engine fuel injection system has been studied in this paper.This paper provides a physical design for 240/275E diesel engine fuel injection system, which includes four parts: fuel injection pump body, fuel injector, fuel injection pump base, fuel injection pipe. The design used the advanced international physical design, and checked this design by theoretically calculation. The oil injection pump is constant plunger pump. The constant delivery valve combination contains delivery valve and return valve. This system can clearly change the pressure wave character of the oil injection. It also can slow up the internal cavitation of high-pressure system and the second injection propensity of fuel injection. Thus, it can improve the coupling's service life, and keep the stabilization of fuel injection pipe's residual pressure. Plunger piston is four-class ex-circle structure, which efficiently improved intensity, and ensured the stabilization of the fuel injection pump. Fuel injectors use the T-series injector nozzles: porous closed type, low-inertia structure of non-cooling type, body-type of fuel injection with supporting panel, adjusting the injection pressure by inside washer. Fuel injection pump base used the guide pin and sliding pin for positioning, this can improve the wear problem and weak intension of set pins, which may cause the following situation of roller wheel units: the fuel feeding cam is affected by losing positioning. The fuel injection pipe unit is a structure of thrust ring, which solved the following problem: oil leakage caused by crack on section of fuel pipe base. This solution apparently guaranteed the safety and reliability operation of locomotives.This thesis developed 240/275E diesel fuel injection system and it past factory's internal tests, e.g. diesel engine performance test, 50h reliability test. It efficiently improved the reliability and economy of 240/275E diesel fuel injection system. This will be welcomed by the locomotive repairing departments, for it can bring apparent economic and social benefits.