本文件规定了关于液化石油气燃料止回阀组件的一般信息，该组件拟用于ISO 3833中定义的机动车类型。它提供了一般设计原则，并规定了说明和标记的要求。它还规定了止回阀的试验要求。 本文件适用于根据ISO 9162使用气体燃料的车辆（单燃料、双燃料或双燃料应用）。它不适用于以下情况: a） 燃料容器； b） 固定式燃气发动机； c） 集装箱安装硬件； d） 电子燃料管理； e） 加油容器。 注1:本文件中未明确说明的其他部件可根据ISO 20766任何适用部分的标准进行检查，包括进行适当的功能测试。 注2:除非另有规定，否则本文件中提及的所有压力均视为表压。 注3:本文件适用于工作压力在110 kPa（20°C时富含丁烷）和840 kPa（20°C时为丙烷）范围内的装置，以下简称本文件。 通过适当的系数（比率）调整压力，可以调节其他工作压力。

This document specifies general information regarding the non-return valve component of liquefied petroleum gas fuel, intended for use on the types of motor vehicles as defined in ISO 3833. It provides general design principles and specifies requirements for instructions and marking. It also specifies test requirements for the non-return valve. This document is applicable to vehicles (mono-fuel, bi-fuel or dual-fuel applications) using gaseous fuels in accordance with ISO 9162. It is not applicable to the following: a) fuel containers; b) stationary gas engines; c) container mounting hardware; d) electronic fuel management; e) refuelling receptacles. NOTE 1 It is recognized that miscellaneous components not specifically addressed herein can be examined for compliance with the criteria of any applicable part of ISO 20766, including testing to the appropriate functional tests. NOTE 2 All references to pressure in this document are considered gauge pressures unless otherwise specified. NOTE 3 This document applies to devices which have a service pressure in the range of 110 kPa (Butane rich at 20 °C) and 840 kPa (Propane at 20 °C), hereinafter referred to in this document. Other service pressures can be accommodated by adjusting the pressure by the appropriate factor (ratio).