GB/T 12536-2017 in English

《GB/T 12536-2017汽车滑行试验方法》由TC114（全国汽车标准化技术委员会）归口，TC114SC19（全国汽车标准化技术委员会整车分会）执行，主管部门为工业和信息化部。

ChinaStandards.net is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.

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The previous editions of the standard superseded by this standard are as follows: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