1 Scope
This standard specifies the structure, performance and test methods for road-vehicle braking systems.
This standard is applicable to the braking systems of Class M and Class N road vehicles as well as Class O trailers.
This standard is not applicable to those road vehicles with their highest design speed less than 25 km/h and their trailers; in addition, it is not applicable to those vehicles driven by the disabled neither.
2 Normative References
The following standards contain provisions which, through reference in this text, constitute provisions of this standard. At time of publication, the editions indicated are valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below.
GB 13594--1992 Vehicles Anti-lock Braking Systems Performance Requirements and Test Procedures
GB/T 14168--1993 Motor Vehicles - Graphical Symbols to Designate Brake Fluid Types
GB/T 5922--1986 Motor Vehicles and Towed Vehicles; Pressure Test Connection for Compressed-air Pneumatic Braking Equipment
3 Terms
3.1 Vehicle type certification
The vehicle type certification which is based on braking device
3.2 vehicle type
The vehicle type which is not different in the following main aspects:
3.2.1 road vehicle
a) Vehicle type;
b) The maximum total mass;
c) Mass distribution between axles;
d) The highest design speed;
e) Braking device (whether trailer is equipped with braking device shall especially be considered);
f) The number and arrangement of axles;
g) Engine type;
h) The gear and speed ratio of transmission;
i) Speed ratio of driving axle;
j) Tire size
3.2.2 Trailer
a) Vehicle type;
b) The maximum total mass;
c) Mass distribution between axles;
d) Driving device;
e) The number and arrangement of axles;
f) Tire size
3.3 Braking device of the same type
The braking devices which are the same in the following main aspects:
a) Characteristic parameter of spares;
b) The type and dimension of spares;
c) The assembling mode of spares
3.4 Hydraulic braking system with energy storage device
The braking system whose energy is supplied by the pressure oil stored in one or several energy storage devices; this kind of pressure oil is supplied by one or several hydraulic pumps with pressure limiting device whose pressure limit is specified by manufacturer.
3.5 Spring braking system
The braking system whose energy for braking is supplied by the one or more than one energy storage springs
3.6 Spring compression chamber
The pressure chamber which generates the pressure change needed by spring compression
3.7 Manufacturer pressure
The pressure specified by manufacturer. Under such pressure, a vehicle shall be able to achieve the specified braking performance and the requirements of energy storage device as well as energy supply device shall be satisfied simultaneously.
3.8 Controllable braking
In this condition, a driver may increase or reduce brake force via control device; the relation between brake force and controlling force is a univalent function and the brake force control is accurate enough.
3.9 Mid-axle trailer
It refers to the coupling device which can not move vertically versus a trailer, the towed vehicle whose axle (single axle or several axles) is close to the gravity center (during uniform loading) of a trailer. The determination of axle position shall ensure small vertical load, i.e. only not greater than 10% trailer maximum total mass or 10 000N (whichever is smaller) can be transmitted to a towing vehicle.
Contents
Foreword
Contents
1 Scope
2 Normative References
3 Terms
4 Structural Requirements on Braking System
4.1 General Provisions
4.2 The Braking Systems of Class M and Class N Road Vehicles
4.3 Braking Device of Class O Trailer
4.4 Spring Braking System
5 Performance Requirements of a Braking System
5.1 General Provisions
5.2 The Braking Performances of Class M and Class N Vehicles
5.3 The Braking Performance of Class O Trailer
5.4 Reaction Time for Service Braking
5.5 Energy Storage Device and Energy Supply Device
5.6 The Conditions not Requiring Type I and Type II (or II A) Tests
6 Test Methods for Braking System
6.1 Test Site
6.2 Climatic Conditions
6.3 Load of Test Vehicle
6.4 Vehicle Preparation
6.5 Test Description
6.6 Type O Service Braking System Test of Class M and Class N Vehicles
6.7 Type-O test of the Class-O trailer service braking system
6.8 Class M and Class N vehicles shall be carried out the urgent braking system test and the service braking partial failure test
6.9 Type I service braking system test of Class M and Class N vehicles
6.10 O-type test of the O-class trailer service braking system
6.11 Type II braking system test of Class M and Class N vehicles
6.12 Type A braking system test of Class M and Class N vehicles
Annex A (Normative) Distribution of Brake Force on Axles, and Harmony Requirements on Braking Between Tow Truck and Trailer
Annex B (Normative) Test Method for Inertia-Type Dynamometer of Brake Lining
Annex C (Normative) Substitution Inspection Specifications for Type I and Type II Tests of Trailer Brake
