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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard supersedes GB/T 12536-1990 Motor Vehicles—Coastdown—Test Method. This standard technically differs from GB/T 12536-1990 mainly in:
——The "Term and Definition" is added;
——Requirements, e.g. "Road", "Environment", "Measurement parameters and their units and accuracy", "Vehicle conditions" are added to the test conditions;
——The test method is further described and the test requirements for automatic transmission vehicles are added;
——The former Chapter 5 "Data Correction Method" is changed into Annex B;
——Some contents of test record are added to Annex A.
This Standard was proposed by the Ministry of Industry and Information Technology of the People's Republic of China.
This standard is under the jurisdiction of the National Technical Committee on Automobiles of Standardization Administration of China (SAC/TC 114).
The previous editions of the standard superseded by this standard are as follows:
——GB/T 1334-1977;
——GB/T 12536-1990.
Coastdown Test Method of Motor Vehicles
1 Scope
This standard specifies coastdown test conditions and methods for various motor vehicles.
This standard is applicable to various motor vehicles.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 12428 Laden Mass Calculating Method for Buses
GB/T 12534 Motor Vehicles—General Rules of Road Test Method
GB/T 15089 Classification of Power—Driven Vehicles and Trailers
3 Term and Definition
For the purposes of this document, the following term and definition apply.
3.1
coast down
the transmission is disengaged from the actuating unit so that the motor vehicle, under straight running, goes forward inertially
4 Test Conditions
4.1 Road
4.1.1 General
The testing road surface shall be hard, straight and even, clean and dry, and provide long enough asphalt pavement or concrete pavement.
4.1.2 Longitudinal slope
The longitudinal slope of testing surface shall not exceed 0.1%.
4.1.3 Transverse slope
The transverse slope of testing surface shall not exceed 3%.
4.2 Environment
4.2.1 Wind velocity
The wind speed during the test shall not be greater than 3.0 m/s. For motor vehicles with a maximum design total mass larger than 3 500 kg, the wind speed shall be measured at 1.6 m higher than the surface; for other motor vehicles, the wind speed shall be measured at 0.7 m higher than the surface.
4.2.2 Humidity
The relative humidity during the test shall be less than 95%.
4.2.3 Temperature
The atmospheric temperature during the test shall range from 0℃ to 40℃.
4.3 Measurement parameters and their units and accuracy
See Table 1 for the requirements of measurement parameters and their units and accuracy.
Table 1 Measurement Parameters, Units and Accuracy
Parameter Unit Accuracy
Time s ±0.1 s
Length m ±0.1%
Atmospheric temperature ℃ ±1℃
Atmospheric pressure kPa ±1 kPa
Tyre pressure kPa ±10 kPa
Speed km/h ±1% or ±0.1 km/h
(whichever is larger)
Mass (≤3 500 kg) kg ±5 kg
Mass (>3 500 kg) kg ±10 kg
4.4 Vehicle conditions
4.4.1 Vehicle running-in
The testing vehicle shall be subjected to running-in as specified by the manufacturer. if there is no such requirement available, at least 3 000 km running-in shall be carried out, after which the vehicle shall be in normal operating condition and the tested tyre pattern depth shall be more than 50% of the original one.
4.4.2 Test mass and load distribution of vehicle
4.4.2.1 Category M1 vehicle and Category N1 vehicle with maximum design total mass less than 2t
4.4.2.1.1 Where 50% of the maximum allowable loading mass of vehicle is less than or equal to 180kg, the test mass is the complete vehicle kerb mass plus 180kg; where 50% of the maximum allowable loading mass of vehicle is greater than 180kg, the test mass of vehicle is the complete vehicle kerb mass plus 50% of the maximum allowable loading mass.
4.4.2.1.2 Load distribution shall be as uniform as possible.
4.4.2.2 Categories M2 and M3 vehicles and Category N vehicles with maximum design total mass not less than 2t
4.4.2.2.1 Unless otherwise specified, the city buses of Categories M2 and M3 are subject to 65% of the loading mass, and other vehicles are subject to full load.
4.4.2.2.2 The load of Categories M2 and M3 motor vehicles is uniformly distributed according to GB/T 12428 while that of Category N vehicles is uniformly distributed according to GB/T 12534.
4.4.3 Vehicle preparation
4.4.3.1 Unless otherwise required, the vehicle shall be clean with the windows and the ventilation devices in passenger cabin shut down.
4.4.3.2 Lighting devices, if may impact the test result as turned on, shall be turned off.
4.4.3.3 The cold inflation pressure of tyre shall meet the technical specification of the vehicle.
4.4.3.4 Prior to testing, the vehicle shall be appropriately made to normal operation temperature.
4.4.3.5 For testing vehicles with energy recovery device, the energy recovery device shall not introduce any force driving the vehicle to coast down or preventing the coastdown when the transmission gear is placed at N position.
Foreword i 1 Scope 2 Normative References 3 Term and Definition 4 Test Conditions 5 Test Method 6 Test Results Annex A (Normative) Data Correction Method Annex B (Normative) Motor Vehicle Coastdown Test Record Sheet
ICS 43.020 T 41 中华人民共和国国家标准 GB/T 12536—2017 代替GB/T 12536—1990 汽车滑行试验方法 Coastdown test method of motor vehicles 2017-10-14发布 2018-05-01实施 中华人民共和国国家质量监督检验检疫总局 中国国家标准化管理委员会 发布 前言 本标准按照GB/T 1.1—2009给出的规则起草。 本标准代替GB/T 12536—1990《汽车滑行试验方法》。与GB/T 12536—1990相比，主要技术变化如下： ——增加了术语和定义； ——试验条件中增加“道路要求”“环境要求”“测量参数及其单位、精确度”“车辆条件”等要求； ——对试验方法进行了细化描述，并增加了对于自动挡汽车的试验要求； ——原第5章“数据校正方法”转为附录B； ——附录A中增加部分试验记录内容。 本标准由中华人民共和国工业和信息化部提出。 本标准由全国汽车标准化技术委员会(SAC/TC 114)归口。 本标准起草单位：中国汽车技术研究中心、广州汽车集团股份有限公司汽车工程研究院、上海机动车检测中心、安徽江淮汽车股份有限公司、中国汽车工程研究院股份有限公司、中国重汽集团济南动力有限公司、海南热带汽车试验有限公司、襄阳达安汽车检测中心、上海汽车集团股份有限公司、泛亚汽车技术中心有限公司、上汽通用五菱汽车股份有限公司、东风汽车有限公司东风日产乘用车公司、一汽丰田技术开发有限公司、广汽丰田汽车有限公司、北汽福田汽车股份有限公司、郑州宇通客车股份有限公司、华晨汽车集团控股有限公司、神龙汽车有限公司、一汽-大众汽车有限公司、戴姆勒大中华区投资有限公司、宝马(中国)服务有限公司、丰田汽车研发中心(中国)有限公司北京分公司。 本标准主要起草人：高岳、王学平、刘桂彬、梁荣亮、张进、苏青瑞、李玉刚、韦小华、石建华、王建业、王国思、朱鑫、叶枫、王晖、冯威、刘钢、尹丽华、王建军、刘磊、周慧慈、张聪、胡浩、王董超、刘丹、李爱国、孙洁。 本标准所代替标准的历次版本发布情况为： ——GB/T 1334—1977； ——GB/T 12536—1990。 汽车滑行试验方法 1 范围 本标准规定了各类汽车进行道路滑行试验的试验条件及试验方法。 本标准适用于各类汽车。 2规范性引用文件 下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本文件。凡是不注日期的引用文件，其最新版本(包括所有的修改单)适用于本文件。 GB/T 12428客车装载质量计算方法 GB/T 12534汽车道路试验方法通则 GB/T 15089机动车辆及挂车分类 3术语和定义 下列术语和定义适用于本文件。 3.1 滑行 coast down 汽车直线行驶时，使传动装置脱离动力机构，靠惯性前进。 4试验条件 4.1道路要求 4.1.1总体要求 试验路面应为坚硬、平直、干净、干燥且足够长的沥青路面或混凝土路面。 4.1.2纵向坡度 试验路面的纵向坡度应不超过0.1％。 4.1.3横向坡度 试验路面的横向坡度应不超过3％。 4.2环境要求 4.2.1 风速 试验时风速应不大于3.0 m/s。对于最大设计总质量大于3 500 kg的汽车，风速应在高出路面1.6 m处测量；对于其他汽车，风速应在高出路面0.7 m处测量。 4.2.2 湿度 试验时相对湿度应小于95％。 4.2.3温度 试验时大气温度应在0℃～40℃之间。 4.3测量参数及其单位、精确度 测量参数及其单位、精确度要求见表1。 表1 测量参数、单位及精确度 参数 单位 精确度 时间 s ±0.1 s 长度 m ±0.1％ 大气温度 ℃ ±1℃ 大气压力 kPa ±1 kPa 轮胎气压 kPa ±10 kPa 速度 km/h ±1％或±0.1 km/h (选取较大值) 质量(≤3 500 kg) kg ±5 kg 质量(>3 500 kg) kg ±10 kg
