Direct injection natural gas engine system and its control method based on ammonia pyrolysis device

Abstract

The invention discloses a direct injection natural gas engine system based on an ammonia pyrolysis device and a control method thereof. The engine system includes an LNG supercharging pressure regulating device, an ammonia pyrolysis device and an electronic control unit of the ammonia pyrolysis device. The control method includes the control of the gas supply process and the control of the ammonia pyrolysis device. The ammonia pyrolysis device realizes catalytic pyrolysis of ammonia, converts liquid ammonia into ammonia pyrolysis gas, feeds it into the intake system of high-pressure direct injection natural gas engine, and supplies an appropriate amount of ammonia pyrolysis gas to the engine cylinder during the engine intake process, optimizing Ammonia pyrolysis gas improves in-cylinder combustion, reduces HC emissions, and meets high emission standards. The LNG supercharging and supercharging pressure regulating device improves the original plunger pump supercharging method to the combined application of the internal gear pump and the LNG supercharging pressure regulating device, making the high-pressure direct-injection natural gas engine work at its best according to the pressure and flow Under the working conditions of LNG boost pressure and LNG flow rate.

Description

technical field [0001] The invention belongs to the field of in-cylinder high-pressure direct-injection natural gas engines, in particular to a direct-injection natural gas engine system based on an ammonia pyrolysis device and a control method thereof. Background technique [0002] The main component of natural gas is methane, which is a clean vehicle fuel. In-cylinder high-pressure direct-injection natural gas engine pressurizes and vaporizes LNG to obtain high-pressure natural gas. The high-pressure natural gas is directly injected into the cylinder to realize diffusion combustion, which has the advantages of high thermal efficiency and low emission. In order to reduce the soot emission of high-pressure direct-injection natural gas engines, the latest high-pressure direct-injection natural gas engines adopt a partial premixed combustion mode, through the pre-injection of natural gas, to improve the mixing degree of natural gas / air. After the partial premixed combustion m...

AI Technical Summary

Problems solved by technology

After the partial premixed combustion mode is adopted, although the thermal efficiency and soot emission of the high-pressure direct injection natural gas engine can be improved, the emission of HC (hydrocarbons) has increased, and the main component of HC emission is methane, which is difficult to eliminate through the post-treatment system

[0003] The literature "Li Menghan, Zhang Qiang, Li Guoxiang, Shao Sidong. Research on the combustion parameters of the external characteristics of the high-pressure direct injection natural gas engine in the cylinder [J]. Natural gas pressure fluctuations will affect the measurement and control accuracy of its consumption rate

Literature "Li, Menghan, Zheng, Xuelong, Liu, Xiaori, et al(2130). The effects of partially premixed combustion mode on the performance and emissions of a direct injection natural gas engine, Fuel, 2130, 260:228-245." The combustion and emission characteristics of the partial premixed combustion mode are disclosed in the high-pressure direct injection natural gas engine. The main defect of the partial premixed combustion mode is that the HC emission is too high

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