高压低温密封技术在氢减压阀中的创新性应用与性能优化研究

Innovative Application and Performance Optimization of High-Pressure Low-Temperature Sealing Technology in Hydrogen Pressure Reducing Valves

摘要: 氢减压阀在车载70 MPa储氢系统中承担降压、稳压与隔离功能，其密封可靠性受高压氢渗透、低温弹性衰减及循环磨损的共同制约。针对传统O形圈密封在高压低温工况下易挤出、易磨损且压力补偿能力不足的问题，本研究提出楔形效应–自润滑协同密封模型，将锥形环自锁阀杆密封、球面–锥面双重密封及PTFE导向环保护结构组合应用于氢减压阀设计。主要材料选取316L不锈钢、6061铝合金、FKM LT橡胶和PEEK工程塑料，通过耐久试验、气密性试验、氢气相容性试验及整车路试进行系统验证。结果表明：在3 MPa~70 MPa结构筛选试验中，本研究阀杆密封结构的泄漏率较传统结构降低90.0%~92.0%；经100,000次耐久循环后，常温氦检平均泄漏率由2.29 × 10⁻⁷ Pa·m³/s降至2.03 × 10⁻⁸ Pa·m³/s，低温(−40℃)平均泄漏率由31 ppm降至0.33 ppm；FKM LT橡胶在70 MPa氢气浸泡试验后平均体积变化率为4.76%，平均质量变化率为0.65%；整车路试100,000 km后平均泄漏率为2.3 ppm。上述结果表明，结构自增压补偿与材料低摩擦耐氢特性的协同设计显著提升了氢减压阀在高压低温工况下的密封可靠性，为车载储氢系统密封方案的工程应用提供了参考。

Abstract: The hydrogen pressure-reducing valve in an onboard 70 MPa hydrogen storage system performs pressure reduction, pressure regulation, and isolation functions, and its sealing reliability is jointly constrained by high-pressure hydrogen permeation, low-temperature elastic degradation, and cyclic wear. To address the limitations of conventional O-ring seals under high-pressure and low-temperature conditions—including susceptibility to extrusion, accelerated wear, and insufficient pressure compensation—this study proposes a wedge-effect/self-lubricating cooperative sealing model. The model integrates a conical-ring self-locking stem seal, a spherical-conical dual seal, and a PTFE guide-ring protection structure into a unified hydrogen pressure-reducing valve design. The primary materials selected were 316L stainless steel, 6061 aluminum alloy, FKM LT rubber, and PEEK engineering plastic. Systematic validation was conducted through endurance testing, leak-tightness testing, hydrogen compatibility testing, and full-vehicle road trials. The results demonstrate that: (1) in structural screening tests across 3~70 MPa, the proposed stem seal reduced leakage rate by 90.0%~92.0% compared with conventional designs; (2) after 100,000 endurance cycles, the room-temperature helium-detection average leakage rate decreased from 2.29 × 10⁻⁷ Pa·m³/s to 2.03 × 10⁻⁸ Pa·m³/s, and the low-temperature (−40˚C) average leakage rate fell from 31 ppm to 0.33 ppm; (3) FKM LT rubber exhibited an average volumetric change of 4.76% and an average mass change of 0.65% after immersion in 70 MPa hydrogen; and (4) the average leakage rate remained 2.3 ppm following 100,000 km of full-vehicle road trials. These findings confirm that the synergistic design combining structural self-pressurization compensation with low-friction, hydrogen-resistant material properties substantially enhances the sealing reliability of hydrogen pressure-reducing valves under high-pressure, low-temperature operating conditions, providing a practical engineering reference for sealing solutions in onboard hydrogen storage systems.