Low-viscosity fuel injector of diesel engine

Abstract

The invention relates to a low-viscosity fuel injector of a diesel engine. The fuel injector mainly comprises a fuel injector body, a needle valve, a needle valve body and a low-pressure-difference control valve. The fuel injector is characterized in that an annular decompression groove on a sliding fit surface of the needle valve and the needle valve body separates a fit clearance into a throttling depressurization clearance and a low-pressure-difference lubricating clearance; the annular decompression groove is communicated with a pressure storage chamber on a low-pressure-difference valve through an oil duct; the middle part of the low-pressure-difference lubricating clearance is communicated with the low-pressure-difference control valve through an annular low-pressure-difference lubricating oil groove and the oil duct; and the low-pressure-difference control valve is communicated with a high-pressure lubricating oil interface through a lubricating oil duct. The seal and lubricating of the sliding fit surface of the needle valve and a guide round hole are ensured by adopting a micro clearance throttling depressurization structure with the pressure storage chamber and a low-pressure-difference liquid seal and lubricating structure, the problem of the wear failure between the needle valve and the guide hole in injecting low-viscosity fuel is overcome, thus the diesel engine can reliably combust low-viscosity replaced fuels, such as dimethy ether, methyl alcohol.

Description

technical field [0001] The invention belongs to the technical field of internal combustion engines, and in particular relates to a fuel injector capable of burning multiple low-viscosity fuels such as dimethyl ether, methanol, and ethanol. technical background [0002] Diesel engines have high thermal efficiency and have become widely used engines in automobiles, tractors, construction machinery, ships, and trains. Diesel engines use diesel oil as fuel. Since the petroleum resources for refining diesel oil have been decreasing year by year in recent years, countries all over the world are looking for and promoting alternative fuels for diesel oil. The emission of dimethyl ether from mechanical injectors for diesel engines is better than Euro III standards, and can reach Euro IV and Euro V emission standards after exhaust gas recirculation is added. Countries all over the world have conducted research and tests, and recognized that coal-based dimethyl ether is a clean fuel t...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to overcome the problem of wear and leakage failure of the needle valve of the fuel injector when the above-mentioned diesel engine is fueled with low-viscosity alternative fuels such as dimethyl ether, and to provide a needle valve that does not rely on fuel oil lubrication and sealing. The low-viscosity fuel injector for diesel engines adopts a micro-gap throttling and pressure-reducing structure with a pressure accumulator and a low-pressure differential liquid lubrication structure.

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