GB/T 45147-2024Road vehicles - Test of vehicle air braking systems with a permissible mass of over 3.5t - Acquisition and use of reference values using a roller brake tester (English PDF)

Foreword

This document was drafted in accordance with the rules given in GB/T 1.1-2020

"Directives for standardization - Part 1.Rules for the structure and drafting of

standardizing documents".

The modification of this document adopts ISO 21995.2008 "Road vehicles -- Test of

vehicle air braking systems with a permissible mass of over 3.5 t -- Acquisition and use

of reference values using a roller brake".

Compared with ISO 21995.2008, this document has more structural adjustments. See

Annex A for a comparison of the structural number changes between the two documents.

The technical differences between this document and ISO 21995.2008 and their reasons

are as follows.

- The terms "brake system", "brake", "braking force", "total braking force", "braking

force distribution ratio", "brake start pressure", "maximum chamber working

pressure" and their definitions have been deleted. The normative reference GB/T

5620 (see Chapter 3) has been added to adapt to Chinese technical requirements;

- ECER13 has been replaced with the normative reference GB 12676-2014 (see 5.2,

Chapter 7) to adapt to Chinese technical requirements;

- The requirement for the minimum braking deceleration of road vehicles has been

changed (see 5.3) to adapt to Chinese regulatory requirements;

- The content of formula (3) has been changed (see 5.5) because the original formula

is ambiguous.

The following editorial changes were made to this document.

- Changed the pressure unit bar in ISO 21995.2008 to kPa throughout the document;

- Added Annex A (informative) "Comparison on structure numbers between this

document and ISO 21995.2008".

Attention is drawn to the possibility that some of the elements of this document may be

the subject of patent rights. The issuing authority shall not be held responsible for

identifying any or all such patent rights.

This document was proposed by Ministry of Industry and Information Technology of

the People's Republic of China.

This document shall be under the jurisdiction of National Technical Committee on

Automobiles of Standardization Administration of China (SAC/TC 114).

Road vehicles -- Test of vehicle air braking systems with a

permissible mass of over3.5 t -- Acquisition and use of

reference values using a roller brake tester

1 Scope

This document describes a method that uses a roller brake tester to acquire and use

vehicle reference values.

This document applies to the testing of air brake systems for road vehicles with a total

mass greater than 3.5 t and equipped with air brake systems.

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 5620, Road vehicles -- Vocabulary and definition for braking of automotive

vehicles and their trailers

GB 12676-2014, Road vehicle -- Braking systems -- Structure, performance and test

methods

3 Terms and definitions

For the purposes of this document, the terms and definitions defined in GB/T 5620 as

well as the followings apply.

4 Symbols

The following symbols apply to this document.

Ff. Total braking force at maximum total mass.

Ff, min. Total braking force required to achieve the required minimum braking intensity.

FNi. Braking force of the i-th axle at brake chamber pressure p N and at the required

minimum braking intensity.

FRi. Braking force of the i-th axle at brake chamber pressure p Ri.

sumFRi. Sum of the braking forces of all axles.

FRiPTI. Reference braking force of the i-th axle (at the corresponding brake chamber

pressure) when the reference braking force meets the requirements of the periodic

technical inspection of motor vehicles (hereinafter referred to as "PTI").

FRiPTI,front. Reference braking force of the i-th front axle when the reference braking

force meets the PTI requirement (at the corresponding brake chamber pressure).

FRiPTI,rear. Reference braking force of the i-th rear axle when the reference braking force

meets the PTI requirement (at the corresponding brake chamber pressure).

Gs. Total normal force corresponding to the maximum total mass of the vehicle.

pRi. Brake chamber pressure of the i-th axle.

pRiPTI. Brake chamber pressure of the i-th axle when the PTI requirement is met.

z. Braking intensity.

zmin. Minimum braking intensity to be achieved under the corresponding total normal

force when performing a PTI check.

FR1.Braking force provided by the vehicle manufacturer for the first point used to

calculate the reference braking force, corresponding to the brake chamber pressure pR1.

pR1.Brake chamber pressure provided by the vehicle manufacturer for the first point

used to calculate the reference braking force, corresponding to the braking force FR1.

FR2.Braking force at the second point provided by the vehicle manufacturer for

calculating the reference braking force, corresponding to the brake chamber pressure

PR2.

PR2.Brake chamber pressure at the second point provided by the vehicle manufacturer

for calculating the reference braking force, corresponding to the braking force FR2.

xRi. Braking start pressure of the i-th axis calculated based on the reference braking

force provided by the vehicle manufacturer.

5 Acquisition methods for reference values