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

摘要： 市场上主流的天然气发动机全部为预混合进气、火花塞点燃式技术，目前一种车用高 压直喷天然气发动机已在开发研究中，可提升现有天然气发动机动力性。高压直喷天然气发 动机需喷入 30 MPa 高压天然气用于燃烧做功，常规车用液化天然气（LNG）供给系统压力较 低，需增加加压装置以满足高压燃气进气需求。文章通过研究 LNG 气瓶内部加压方式，设计 使用液压驱动的低温泵将 LNG 液体加压抽出，汽化后形成高压燃气供发动机使用，同时监控 燃气进气压力、进气温度，以更加精确的控制燃气供给。通过试验验证，该高压 LNG 供给系 统各项指标满足设计要求，系统能够稳定、精确的进行高压燃气供给。

关键词: 高压直喷天然气发动机；高压 LNG 供给系统；高压燃气