前言:这是CSA/ANSI NGV 3.1《压缩天然气动力汽车的燃料系统部件》的第四版。它取代了之前在2014年、2012年和1995年发布的ANSI NGV 3.1•CSA 12.3版本。本版本的主要变化包括:a）参考文献已更新。b） 为了提高可读性，对编辑/符号进行了修改。c） 已添加注释以供参考。d） 对以下条款进行了技术更改:5.3.3、5.4、5.5、5.7.3.3、5.11、7.3、7.4、10.4.2、14.4.4、14.4.6和16.4.4.2。e） 增加了以下新条款:5.16、6.5、9.4.3.1、9.4.4、10.4.4、11.3、11.4.4、11.4.5、15.4.4.3、19.4.6、19.4.8和21.4.2。CSA集团承认，该标准的制定部分是由于加拿大自然资源部的财政支持。本标准的制定符合加拿大标准委员会对加拿大国家标准的要求。 CSA集团已将其作为加拿大国家标准发布。本标准已被美国国家标准协会（ANSI）批准为美国国家标准。范围:1.1本标准规定了拟用于天然气动力车辆的新生产压缩天然气燃料系统部件的要求，如下表1所示。止回阀手动阀手动容器阀自动阀喷油器压力指示灯压力调节器气体流量调节器气体/空气混合器减压阀减压装置溢流阀气密壳和通风软管刚性燃油管路柔性燃油管路、软管和组件滤清器配件排放管路关闭1。2本标准适用于工作压力（SP）为16500千帕（2400磅/平方英寸）、20700千帕（3000磅/平方英寸）或24800千帕（3600磅/平方英寸）的装置，以下在本标准中称为: a） “P24”——16547千帕（2400磅平方英寸）；b） “P30”——20684千帕（3000磅/平方英寸）；orc）“P36”——24 821千帕（3600磅平方英寸）。本标准也适用于第一阶段减压的下游部件。1.3无论本标准的各项规定是否具体涵盖，所述部件的构造应符合安全、性能和耐久性的合理概念。1.4本协议规定的所有施工规范应通过实际规定的施工或至少提供同等性能的其他施工来满足。1.5本标准强调了表1.1.6中所列部件的压力控制、性能和安全特性。我们认识到，本标准中未具体涵盖的其他部件可以进行检查，以满足本标准的标准，并根据适当的功能需求进行测试。 1.7本标准不适用于以下情况:a）最初根据联邦机动车安全标准（FMVSS）和加拿大机动车安全标准（CMVSS）制造的机动车制造过程中使用的天然气燃料系统部件；b） 燃料容器；c） 固定式燃气发动机；d） 集装箱安装硬件；e） 电子燃料管理；f） 燃料容器；org）三通阀。1.8如果本标准与联邦、省、州或地方要求存在冲突，应以政府要求为准。1.9除非另有规定，本标准中所有提及的“kPa（psi）”均应视为表压。1.10本标准包含与码/磅数量相对应的SI（公制）单位，目的是允许使用SI（公制）单位。 IEEE/ASTM SI 10，美国国家公制实践标准，或ISO 80000-1:2009数量和单位-第1部分:概述，用作从码/磅数量进行公制转换的指南。如果规定了测量值和其他单位的相应值，则应将第一个规定值视为要求。给定的相应值可能是近似值。如果测量值和其他单位的相应值都被规定为引用标记要求，则应提供第一个或两个规定的单位。1.11在本标准中，“应”用于表示要求，即用户为遵守本标准而有义务满足的规定；“应该”用于表示建议或建议但不需要的建议；“可”用于表示一个选项或在标准范围内允许的选项。 注释随附条款不包括要求或替代要求；随附条款的注释的目的是将解释性或信息性材料与文本分开。表和图的注释被视为表或图的一部分，可以作为要求编写。附件被指定为规范性（强制性）或信息性（非强制性）以定义其应用。1.12国际单位制给出的数值为本标准中的记录单位。括号中给出的值仅供参考和比较。

Preface:This is the fourth edition of CSA/ANSI NGV 3.1,Fuel system components for compressed natural gas powered vehicles. It supersedes the previous editions published in 2014, 2012, and 1995 as ANSI NGV 3.1 • CSA 12.3.The major changes to this edition include the following:a) References have been updated.b) Editorial/notation changes have been made to improve readability.c) Notes have been added for guidance.d) Technical changes have been made to the following Clauses: 5.3.3, 5.4, 5.5, 5.7.3.3, 5.11, 7.3, 7.4, 10.4.2, 14.4.4, 14.4.6, and 16.4.4.2.e) The following new Clauses have been added: 5.16, 6.5, 9.4.3.1, 9.4.4, 10.4.4, 11.3, 11.4.4, 11.4.5, 15.4.4.3, 19.4.6, 19.4.8, and 21.4.2.CSA Group acknowledges that the development of this Standard was made possible, in part, by the financial support of Natural Resources Canada.This Standard has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group.This Standard has been approved by the American National Standards Institute (ANSI) as an American National Standard.Scope:1.1This Standard establishes requirements for newly produced compressed natural gas fuel system components, intended for use on natural gas powered vehicles, as listed in Table 1 below.Check valvesManual valvesManual container valvesAutomatic valvesGas injectorsPressure indicatorsPressure regulatorsGas flow adjustersGas/air mixersPressure relief valvesPressure relief devicesExcess flow valvesGas-tight housing and ventilation hosesRigid fuel linesFlexible fuel line, hoses, and assembliesFiltersFittingsDischarge line closures1.2This Standard applies to devices that have a service pressure (SP) of either 16 500 kPa (2400 psi), 20 700 kPa (3000 psi), or 24 800 kPa (3600 psi), hereinafter referred to in this Standard as the following:a) "P24" – 16 547 kPa (2400 psi);b) "P30" – 20 684 kPa (3000 psi); orc) "P36" – 24 821 kPa (3600 psi).The Standard also applies to components downstream of the first stage of pressure reduction.1.3The construction of the noted components, whether specifically covered by the various provisions of this Standard or not, should be in accordance with reasonable concepts of safety, performance, and durability.1.4All specifications as to construction set forth herein should be satisfied by the construction actually prescribed or such other construction as will provide at least equivalent performance.1.5This Standard emphasizes the pressure containment, performance, and safety characteristics of components listed in Table 1.1.6It is recognized that other components not specifically covered herein can be examined to meet the criteria of this Standard and tested according to the appropriate functional needs.1.7This Standard does not apply to the following:a) natural gas fuel system components incorporated during the manufacture of motor vehicles originally manufactured in compliance with theFederal Motor Vehicle Safety Standards (FMVSS) for Compressed Natural Gas Fueled Vehicles and the Canadian Motor Vehicle Safety Standard (CMVSS);b) fuel containers;c) stationary gas engines;d) container mounting hardware;e) electronic fuel management;f) fuelling receptacles; org) three-way valves.1.8In the case of conflict between this Standard and federal, provincial, state, or local requirements, the government requirements should take precedence.1.9All references to "kPa (psi)" throughout this Standard should be considered gauge pressures, unless otherwise specified.1.10This Standard contains SI (metric) units corresponding to the yard/pound quantities, the purpose being to allow the Standard to be used in SI (metric) units. IEEE/ASTM SI 10,American National Standard for Metric Practice, or ISO 80000-1:2009Quantities and units — Part 1: General, is used as a guide in making metric conversion from yard/pound quantities. If a value for a measurement and a corresponding value in other units are stated, the first stated value should be regarded as the requirement. The given corresponding value may be approximate. If a value for a measurement and a corresponding value in other units, are both specified as a quoted marking requirement, the first stated unit, or both, are to be provided.1.11In this Standard, "shall" is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the Standard; "should" is used to express a recommendation or that which is advised but not required; and "may" is used to express an option or that which is permissible within the limits of the Standard. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.1.12The values given in SI units are the units of record for the purposes of this Standard. The values given in parentheses are for information and comparison only.