Combined Dual Piezo Hybrid Fuel Injection Device

Abstract

The invention aims at providing a combined dual piezoelectric mixed fuel injection device. The device comprises a dual piezoelectric control part, a nozzle part, a fuel gas inlet channel, a fuel oil inlet channel and the like. A fuel gas nozzle and a fuel oil nozzle are combined in an injection device shell, the two nozzles each adopts a piezoelectric element to control motion of a corresponding needle valve, the needle valve lift is adjustable, and the control accuracy of the fuel oil injection amount and fuel injection rate is high; two needle valves are adopted by the nozzles to control fuel oil injection and fuel gas injection respectively, the fuel injection flexibility is high, and a pure fuel working mode and a dual-fuel working mode 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; fuel gas of the fuel gas nozzle is sealed with the fuel oil, the situation that the fuel gas is leaked through the needle valve matching parts is avoided, the fuel gas injection pressure and injection speed are increased, and the power property of an engine and the fuel economical efficiency are improved.

Description

technical field [0001] The invention relates to a fuel injection device, in particular to an engine mixed 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 electromagnetically controlled gas nozzles and fuel ...

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Problems solved by technology

[0003] The existing in-cylinder direct-injection dual-fuel engines mostly use electromagnetically controlled gas nozzles and fuel nozzles. The disadvantages are: the solenoid valve control device is affected by the hysteresis loop and the inductance of the electromagnetic coil, and the response of the needle valve is relative to the control. The signal is delayed, which affects the control accuracy; the gas nozzle and the fuel nozzle are independently installed on the cylinder head, and the size and installation position are limited by the cylinder head; 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 realize Accurate control of needle valve movement, unstable gas injection; fuel injection control is achieved by controlling the pressure difference between the top of the piston and the cone surface of the needle valve in the fuel nozzle, the movement mass is large, the response speed is slow, and the high pressure in the control chamber and oil tank Fuel will leak to the low-pressure end where the return spring of the needle valve is located; in addition, during the gas injection process, with the movement of the needle valve, the gas leaks to the electromagnetic valve end through the gap between the needle valve and the valve body intensified, resulting in gas injection pressure and The injection rate is reduced, which has a negative impact on the stability of gas injection, affecting engine power and fuel economy

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