Combined Mechanical Injection-Boost Piezojet Mixed Fuel Injection Device

Abstract

The invention aims at providing a combined mechanical fuel oil injection and pressurizing piezoelectric fuel gas injection mixed fuel injection device. The mixed fuel injection device comprises a fuel gas pressurizing part, a pressure adjusting spring, a piezoelectric control part, a mechanical nozzle, a fuel gas nozzle, a fuel gas inlet channel, a fuel oil inlet channel and the like. A pressurizing electromagnetic valve is adopted by the fuel gas pressurizing part to control motion of a pressurizing piston to achieve fuel gas pressurization, fuel gas pressurizing timing is controllable, switching of fuel gas pressurizing injection and fuel gas non-pressurizing injection can be rapidly achieved, and the different requirements of different powers of a dual-fuel engine on fuel gas injection pressure are met; the mechanical nozzle is used for achieving fuel oil injection, a piezoelectric element is adopted by the piezoelectric control part to control the fuel gas nozzle to achieve fuel gas injection, the flexibility of fuel injection is high, and switching of pure fuel oil injection and fuel oil and fuel gas dual-fuel injection can be achieved; fuel oil in a needle valve cavity of the fuel gas nozzle and fuel oil at needle valve matching parts of the fuel gas nozzle are the same oil, the oil pressures are equal, and static leakage of the fuel oil at the needle valve matching parts is avoided.

Description

technical field [0001] The invention relates to a fuel injection device, in particular to a dual-fuel engine fuel injection device. Background technique [0002] The development of alternative fuels for engines is one of the very effective means to solve the problems of energy shortage and environmental pollution. Due to the advantages of abundant reserves, low price and low pollution emissions, gaseous fuel has become an alternative fuel for engines with good development prospects. Although the gas engine using only one gas fuel has clean emissions, the gas fuel used has low energy density, high fuel consumption, and limited use direction; while the dual-fuel engine using diesel as the pilot fuel and gas fuel as the main fuel can be used in Flexible switching between the two fuels, high fuel substitution rate, good power, economy and emissions. [0003] The existing in-cylinder direct-injection dual-fuel engines mostly use electromagnetic gas nozzles and mechanical nozzle...

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Problems solved by technology

[0003] The existing in-cylinder direct-injection dual-fuel engines mostly use electromagnetic gas nozzles and mechanical nozzles to achieve dual-fuel injection, and gas boosters mostly use high-pressure pumps to compress the gas to the specified pressure. The shortcomings include: gas nozzles and mechanical nozzles The nozzle is independently installed on the cylinder head, and the size and installation position are limited by the cylinder head; the high-pressure pump has a complex structure, the transmission pipe from the pump end to the gas nozzle is long, and there is a certain leakage of the pressurized gas; the gas nozzle uses the pressure gas to lift the needle valve , but due to the strong compressibility of the gas, it is not conducive to the precise control of the needle valve movement, and the gas injection is unstable; in addition, during the gas injection process, the gas passes through the gap between the needle valve and the valve body to the electromagnetic Leakage at the valve end increases, resulting in a decrease in gas injection pressure and injection rate, which has a negative impact on the stability of gas injection and affects engine power and fuel economy

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