GB/T 12542-2020Thermal balance capacity on-road test method for motor vehicles (English PDF)

Foreword

This Standard was drafted as per the rules specified in GB/T 1.1-2009. This Standard replaced GB/T 12542-2009 Thermal Balance Capacity on-Road Test Method for Motor Vehicles. Compared with GB/T 12542-2009, this Standard has the major technical changes as follows besides the editorial modifications:

--- Add the provisions for indoor tests, and revise the provisions for applicable vehicle models (see Clause 1 of this Edition);

--- Modify the definitions of environment temperature and motor vehicle thermal balance (see 3.1,

3.3 of this Edition; 3.1,

3.4 of 2009 Edition);

--- Replace the cooling constant by the temperature difference constant; replace the maximum approved temperature of the cooling medium by the temperature limit; replace the approved environment temperature for limit use and approved environment temperature for normal use by the approved environment temperature (see 3.4, 3.6,

3.7 of this Edition; 3.5, 3.6, 3.9,

3.10 of 2009 Edition);

--- Add the terms and definitions of temperature difference, resistance apply device, the maximum torque speed, rated power speed, and no obvious upward trend (see 3.2, 3.5, 3.8, 3.9,

3.10 of this Edition);

--- Delete the terms and definitions of cooling medium, thermal balance, limit use conditions, and normal use conditions (see 3.2, 3.3, 3.7,

3.8 of 2009 Edition);

--- Modify the relevant requirements for climatic conditions and measurement parameters (see 4.1,

4.3 of this Edition;

1 Scope

GB/T 12542-2020 is the Chinese national standard on thermal balance capacity on-road test method for motor vehicles, in the field of road vehicles engineering. The /T suffix marks it as a recommended standard: it is not compulsory by itself, but it becomes binding as soon as a contract, a tender or a customer specification calls it up - which in practice is how most foreign buyers meet it. It was issued on 29 September 2020 by the State Administration for Market Regulation; Standardization Administration of China, and has been in force since 1 April 2021. Classification: ICS 43.020, CCS T04. This page is published from the official record of the standard held by the Chinese standards administration: the identification, the dates, the classification and the issuing body are taken from there. The clause text, the tables and the numeric limits are in the document itself, which is delivered complete in English translation.

This Standard specifies the test conditions, test preparation, test methods, data processing and test reports for the thermal balance capacity on-road test method of for motor vehicles. This Standard is applicable to the thermal balance capacity on-road test of Type-M and Type-N vehicles with forced circulation liquid-cooled engines, which can be implemented by reference when testing indoors; other Type-M and Type-N vehicles can also be implemented by reference.

2 Normative References

The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) is applicable to this document.

GB/T 3730.2 Road Vehicle - Masses - Vocabulary and Codes

GB/T 12534 Motor VehiclesGeneral Rules of Road Test Method

GB/T 15089 Classification of Power-Driven Vehicles and Trailers

3 Terms and Definitions

For the purpose of this document, the terms and definitions given in GB/T 3730.2, GB/T 15089 and the following apply.

3.1 Environment temperature The temperature of the environment where the vehicle is located. NOTE: During the measurement, the sensor for measuring the environment temperature is installed on the outside of the sample vehicle in an appropriate manner, 1.5m from the ground. Avoid direct sunlight, reflections and interference from other heat sources.

3.2 Temperature difference; DeltaT The difference between the temperature of each system, assembly, and parts of the automobile and the environment temperature.

3.3 Motor vehicles thermal balance The temperature difference between the temperature of each system, assembly and parts of the automobile and the environment temperature becomes stable.

3.4 Temperature difference constants; DeltaTc The temperature difference of each system, assembly and parts of the automobile during the thermal balance.

3.5 Resistance apply device The device that provides the driving resistance (such as load trailer, chassis dynamometer, etc.), which may be measured.

3.6 Temperature limits; Tlim The maximum approved operating temperature of each system, assembly, and parts of the automobile that is given by the automobile manufacturer.

3.7 Approved environment temperature; Tapr Due to the limitation of temperature limit, the highest environment temperature at which the automobile can work normally.

3.8 The maximum torque speed; nt The speed at the maximum torque of the automobile engine; if the engine obtains the maximum torque at different speeds, it is the highest speed corresponding to the maximum torque of the engine.

3.9 Rated power speed; np The speed at maximum power of the automobile engine; if the engine obtains the maximum power at different speeds, it is the highest speed corresponding to the maximum power of the engine.

3.10 No obvious upward trend The temperature rise is less than 2°C within 4min, and the temperature rise rate of the latter is less than that of the former between the two adjacent time periods.

5.1.4 Fire extinguishers shall be prepared to ensure the safety of the test.

5.1.5 Before the test, the automobile shall be technically inspected and maintained in accordance with the provisions and requirements of the automobile's instruction manual and related technical conditions; especially the thermostat, cooling fan, radiator expansion valve, etc.

5.1.6 If necessary, the engine coolant, engine lubricating oil, gearbox lubricating oil and transaxle lubricating oil shall be replaced in accordance with the model and quantity specified in the automobile's instruction manual.

6 Test Methods

6.1 Automobile preheating The automobile preheating shall be carried out according to GB/T 12534.