Supercharged common rail fuel injection system of marine low-speed diesel engine

Abstract

A supercharged common rail fuel injection system of a marine low-speed diesel engine comprises a servo fuel supplying part, a common rail fuel injector and a fuel supplying part, wherein the servo fuel supplying part and the fuel supplying part respectively supply servo fuel and fuel to the common rail fuel injector; in the common rail fuel injector, an upper supercharged piston chamber and a lower supercharged piston chamber are formed between a supercharging piston and a supercharging piston body; a supercharging piston control valve controls whether the servo fuel supplying part and the upper supercharged piston chamber are communicated or cut off, so that the supercharging or suction of the fuel is realized; supercharged high-pressure fuel in the lower supercharged piston chamber is divided into two paths: one enters a control chamber and the other enters a fuel holding tank; a fuel injection control electromagnetic valve performs precise and flexible control under all working conditions to the fuel injection timing and the cyclic fuel injection quantity of the common rail fuel injector. According to the supercharged common rail fuel injection system of the marine low-speed diesel engine, the fuel supercharging process and the fuel injection process are completely separated; multiple injections in one circulation is allowed, and the fuel economy and the emission performance of the diesel engine are improved.

Description

technical field [0001] The invention relates to an engine fuel injector, in particular to a pressurized common rail fuel injection system for a high-power marine low-speed diesel engine, and belongs to the technical field of diesel engines. Background technique [0002] Mechanical fuel injectors cannot achieve precise and flexible control of fuel injection timing, fuel injection regularity and cycle fuel injection volume, and due to the existence of pulsating fuel supply, the fuel injection pressure is low and the fuel atomization quality is poor under low-speed and small-load conditions. Poor, which reduces the fuel economy of diesel engines and deteriorates the emissions of diesel engines, so mechanical injectors can no longer meet the requirements of increasingly stringent emission regulations. [0003] The common rail fuel injection system for diesel engines can realize precise and flexible control of fuel injection timing and cycle fuel injection volume, and is an effec...

AI Technical Summary

Problems solved by technology

The disadvantage is that this patent uses a flat valve with poor sealing performance under high pressure conditions to seal the oil orifice on the control chamber, especially when the fuel pressure in the control chamber is relatively high or super high pressure , the sealing performance of the flat valve deteriorates sharply, and the fuel leakage increases rapidly, which seriously affects the working characteristics of the common rail injector

[0006] Chinese patent CN 102392771A uses a two-position three-way solenoid valve to replace the two-position two-way electromagnetic control flat valve on the Chinese patent CN 102022241A that controls the movement of the booster piston, which solves the problem of poor high-pressure sealing caused by the use of flat valves

But its shortcoming is that this patent is the same as patents CN 102022241A and CN 102705121A. It realizes the control of the movement of the booster piston through the control of fuel drain and oil filling in the control chamber under the small head of the booster piston, thereby Complete the fuel pressurization process and the oil suction process, however, this control method for the movement of the booster piston requires precise matching of the oil inlet orifice and the oil discharge orifice on the control chamber, which will inevitably lead to increased processing costs and difficulty in manufacturing increase, and because the upper part of the booster piston always has high-pressure fuel, when the booster piston resets upward, due to the downward force generated by the high-pressure fuel, the booster piston is difficult to reset quickly, which will significantly reduce the effective filling time , which limits the coverage of diesel engine power

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