关键词: 高压直喷天然气发动机；高压 LNG 供给系统；高压燃气

Abstract: All mainstream natural gas engines on the market adopt the technology of pre-mixed intake and spark ignition. At present, a high-pressure direct-injection natural gas engine for vehicles is under research and development, which can improve the power performance of existing natural gas engines. High-pressure direct-injection natural gas engines require high-pressure natural gas at 30 MPa to be injected for combustion and power output. Conventional vehicle liquefied natural gas (LNG) supply systems operate at relatively low pressure, so a pressurization device must be added to meet the high-pressure gas intake requirement. This paper studies the internal pressurization method inside the LNG cylinder, and designs a hydraulically driven cryogenic pump to pressurize and extract LNG liquid. After vaporization, high-pressure gas is formed for engine use. Meanwhile, the gas intake pressure and intake temperature are monitored to achieve more precise control of gas supply. Experimental verification shows that all indicators of the high-pressure LNG supply system meet the design requirements, and the system can provide stable and accurate high-pressure gas supply.

Key words: high-pressure direct injection natural gas engine; high-pressure LNG supply system;high-pressure fuel gas