GB 12676-2014 English PDF

Delivery: 2 working-hours manually (Sales@ChineseStandard.net)
Need delivered in 3-second? USA-Site: GB 12676-2014
Get Quotation: Click GB 12676-2014 (Self-service in 1-minute)
Historical versions (Master-website): GB 12676-2014
Preview True-PDF (Reload/Scroll-down if blank)

GB 12676-2014: Road vehicle -- Braking systems -- Structure, performance and test methods
GB 12676-2014
NATIONAL STANDARD OF THE
PEOPLE?€?S REPUBLIC OF CHINA
ICS 43.040.40
T 24
GB/T 12676-2014
Replacing GB/T 12676-1999
Technical Requirements and Testing Methods for
Commercial Vehicle and Trailer Braking Systems
ISSUED ON: OCTOBER 10, 2014
IMPLEMENTED ON: JULY 01, 2015
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of PRC;
Standardization Administration of PRC.
Table of Contents
Foreword ... 4??
1?? Scope ... 9??
2?? Normative References ... 9??
3 ?? Terms and Definitions ... 10??
4?? Specifications ... 16??
5?? Tests and Performance Requirements ... 43??
6?? Approval of Vehicle Type and Extension of Approval ... 61??
7?? Conformity of production (COP) ... 63??
Annex A (Normative) Procedure for Monitoring the State of Battery Charge ... 64??
Annex B (Normative) Method of measuring the response time on vehicles equipped
with compressed-air braking systems ... 65??
Annex C (Normative) Provisions relating to energy sources and energy storage devices
(energy accumulators) ... 71??
Annex D (Normative) Provisions relating to specific conditions for spring braking
systems ... 79??
Annex E (Normative) Distribution of braking among the axles of vehicles and
requirements for compatibility between towing vehicles and trailers ... 82??
Annex F (Normative) Test procedure to assess the functional compatibility of vehicles
equipped with electric control lines ... 96??
Annex G (Normative) Inertia dynamometer test method for brake linings ... 103??
Annex H (Normative) Special requirements to be applied to the safety aspects of
complex electronic vehicle control systems ... 107??
Annex I (Normative) Test conditions for trailers with electrical braking systems ... 112??
Annex J (Normative) Cases in which Type- I and/or Type-II (or Type-IIA) or Type-III
tests do not have to be carried out ... 115??
Annex K (Normative) Alternative procedures for Type-I and Type-III tests for trailer
brakes ... 117??
Annex L (Normative) Conditions governing the testing of vehicles equipped with inertia
(overrun) braking systems ... 124??
Foreword
All specifications of this standard are compulsory.
This standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB 12676-1999, Road vehicle-Braking systems-Structure, performance and
test methods. Compared with GB 12676-1999, the following significant changes have been made:
?€? Deleted the content of the vehicles of Category M1;
?€? Added the following terms and definitions: Braking system, Control, Transmission, Brake,
Different types of braking systems, Component of a braking system, Continuous braking,
Semi-continuous braking, Automatic braking, Inertia (or overrun) braking, Progressive and
graduated braking, Phased braking, Endurance braking system, Laden, Unladen, The
distribution of mass among the axles, Wheel/axle load, Maximum stationary wheel/axle load,
Electric regenerative braking, Simultaneous lockup of the front and rear wheels, Electric
control line, Data communication, Point-to-point, Coupling force control, Nominal value,
Automatically commanded braking, Selective braking and Reference braking forces, etc.;
?€? Deleted the following terms: Approval of a vehicle, braking of the same type, spring braking
system, pressure defined by the manufacturer and controllable braking, etc.;
?€? Added the requirements for electric control line in the connections, for compressed-air braking
systems, between power-driven vehicles and trailers (See 4.1.3, or 4.1.5 in GB 12676-1999);
?€? Added the provisions for the periodic technical inspection of braking systems (See 4.1.4);
?€? Added the provisions on safety of complex electronic control system (See 4.1.5);
?€? Added the requirements for distribution of the action of service braking system between the
wheels of one and the same axle (See 4.2.1.8 and 4.2.2.5);
?€? Added the scope of vehicle categories that shall be equipped with an anti-lock braking system
(See 4.2.1.22 and 4.2.2.13);
?€? Added the additional requirements for vehicles of categories M2, N1 and category N2 ?€? 5,000
kg equipped with an electric regenerative braking system (See 4.2.1.24);
?€? Added the special additional requirements for the electric transmission of the parking braking
system (See 4.2.1.25);
?€? Added the special additional requirements for service braking systems with electric control
transmission (See 4.2.1.26 and 4.2.2.15);
?€? Added the special requirements for coupling force control system (See 4.2.1.27);
?€? Added the Free running test (See 5.1.5.4);
?€? Added the Type-III test (See 5.1.7);
?€? Added the scope of vehicle categories that shall be subject to the Type-II A test: (See 5.1.8.1);
?€? Added the minimum braking performance requirements for the power-driven vehicles that are
allowed to be coupled with the unbraked trailer (See 5.2.1.2);
?€? Added the additional failure check and performance requirements for vehicles employing
electric regenerative braking systems in emergency brake test (See 5.2.2.6);
?€? Modified the evaluation indicators for the laden stopping distance of Category M2 and the
unladen stopping distance of Category N1 (See 5.2.4.1, or 5.2.2 in GB 12676-1999);
?€? Incorporated the Clause 6 ?€?braking system test method?€? into the Clause 5, and cancelled the
optional test (See Clause 5, or Clause 6 in GB 12676-1999);
?€? Added the approval of vehicle type and extension of approval (See Clause 6);
?€? Added the conformity of production (See Clause 7);
?€? Added the procedure for monitoring the state of battery charge (See Annex A);
?€? Added the method of measuring the response time on vehicles equipped with compressed-air
braking systems (See Annex B);
?€? Added the provisions relating to energy sources and energy storage devices (energy
accumulators) (See Annex C);
?€? Added the provisions relating to specific conditions for spring braking systems (See Annex D);
?€? Added the test procedure to assess the functional compatibility of vehicles equipped with
electric control lines (See Annex F);
?€? Added the special requirements to be applied to the safety aspects of complex electronic
vehicle control systems (See Annex H);
?€? Added the test conditions for trailers with electrical braking systems (See Annex I);
Technical Requirements and Testing Methods for
Commercial Vehicle and Trailer Braking Systems
1 Scope
This Standard specifies the technical requirements and testing methods for commercial vehicle and
trailer braking systems.
This Standard applies to power-driven vehicles of categories M2, M3 and N AND trailers of category
O, as specified in GB/T 15089.
This Standard does not cover:
?€? Vehicles with a design speed not exceeding 25 km/h;
?€? Trailers which may not be coupled to power-driven vehicles with a design speed exceeding
25 km/h.
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 3730.1 Motor vehicles and trailers-Types-Terms and definitions
GB/T 3730.2 Road vehicle-Masses-Vocabulary and codes
GB/T 5620 Road vehicles - Braking of automotive vehicles and their trailers - Vocabulary
GB/T 5922 Motor vehicles and towed vehicles - Pressure test connection for compressed-air
pneumatic braking equipment
GB/T 13594-2003 Antilock braking performance and test procedure for motor vehicles and their
trailers
GB/T 15089 Classification of power-driven vehicles and trailers
?€? The number and ratios of gears;
?€? The final drive ratios;
?€? The tyre dimensions;
3.1.1.2 Trailer
With regard to braking system, the vehicles which do not differ in such essential respects as:
?€? The vehicle category;
?€? The maximum design total mass;
?€? The distribution of mass among the axles;
?€? A different type of braking equipment;
?€? The number and arrangement of the axles;
?€? The tyre dimensions;
3.1.2 "Braking system" means the combination of parts whose function is progressively to reduce
the speed of a moving vehicle or bring it to a halt, or to keep it stationary if it is already halted. The
system consists of the control, the transmission, and the brake proper;
3.1.3 "Actuation" means both application and release of the control.
3.1.4 "Transmission device" means the combination of components comprised between the control
and the brake and linking them functionally. The transmission may be mechanical, hydraulic,
pneumatic, electric or mixed. Where the braking power is derived from or assisted by a source of
energy independent of the driver, the reserve of energy in the system is likewise part of the
transmission.
The transmission is divided into two independent functions: the control transmission and the energy
transmission. Whenever the term "transmission" is used alone in this Standard, it means both the
"control transmission" and the "energy transmission". The control and supply lines between towing
vehicles and trailers shall not be considered as parts of the transmission.
3.1.4.1 "Control transmission device" means the combination of the components of the transmission
which control the operation of the brakes, including the control function and the necessary reserve(s)
of energy.
3.1.4.2 "Energy transmission device" means the combination of the components which supply to the
?€? The braking installation ensures simultaneous or suitably-phased braking of each of the
constituent vehicles of the combination, whatever their relative positions;
3.1.10 "Automatic braking" means braking of the trailer or trailers occurring automatically in the
event of separation of components of the combination of coupled vehicles, including such
separation through the breakage of a coupling, the effectiveness of the braking of the remainder of
the combination not being thereby destroyed;
3.1.11 "Inertia (or overrun) braking" means braking by utilizing the forces generated by the trailer's
moving up on the towing vehicle;
3.1.12 "Progressive and graduated braking/modulatable braking" means braking during which,
within the normal operating range of the equipment and during actuation of the brakes, the driver
can at any moment increase or decrease the braking force by acting on the control and the braking
force varies proportionally as the action on the control (monotonic function), which can be easily
regulated with sufficient precision;
3.1.13 "Phased braking" is a means which may be used where two or more sources of braking are
operated from a common control, whereby one source may be given priority by phasing back the
other source(s) so as to make increased control movement necessary before they begin to be
brought into operation.
3.1.14 "Endurance braking system" means an additional braking system having the capability to
provide and to maintain a braking effect over a long period of time without a significant reduction in
performance. The term "endurance braking system" covers the complete system including the
control device. This definition doesn?€?t cover the vehicles equipped with electric regenerative braking
system.
The endurance braking system may comprise a single device or a combination of several devices.
Each device may have its own control.
3.1.14.1 "Independent endurance braking system" means an endurance braking system whose
control device is separated from that of the service and other braking systems;
3.1.14.2 "Integrated endurance braking system" means an endurance braking system whose
control device is integrated with that of the service braking system in such a way that both
endurance and service braking systems are applied simultaneously or suitably phased by operation
of the combined control device;
3.1.14.3 "Combined endurance braking system" means an integrated endurance braking system,
which in addition has a cut-out device, which allows the combined control to apply the service
braking system alone.
3.1.15 ?€?Unladen condition?€? means the complete vehicle kerb mass adding 110 kg.
3.1.24 "Data communication" means the transfer of digital data under the rules of a protocol.
3.1.25 "Point-to-point" means a topology of a communication network with only two units. Each unit
has an integrated termination resistor for the communication line.
3.1.26 "Coupling force control system" means a system/function to automatically balance the
braking rate of towing vehicle and trailer.
3.1.27 "Nominal value" definitions for braking reference performance are required to put a value on
the transfer function of the braking system, relating output to input for vehicles individually and when
used in combination.
"Nominal value" is defined, for a power-driven vehicle, as the characteristic which relates the
braking rate of the vehicle on its own to the level of the braking input variable.
"Nominal value" is defined, for a trailer, as the characteristic which relates the braking rate to the
coupling head signal.
"Nominal demand value" is defined, for coupling force control, as the characteristic which relates the
coupling head signal to the braking rate.
3.1.28 "Automatically commanded braking" means a function within a complex electronic control
system where actuation of the braking system(s) or brakes of certain axles is made for the purpose
of generating vehicle retardation with or without a direct action of the driver, resulting from the
automatic evaluation of on-board initiated information.
3.1.29 "Selective braking" means a function within a complex electronic control system where
actuation of individual brakes is made by automatic means in which vehicle retardation is secondary
to vehicle behavior modification.
3.1.30 "Reference braking forces" means the braking forces of one axle generated at the
circumference of the tyre on a roller brake tester.
3.2 Terms and definitions of complex electronic vehicle control system
3.2.1 "Safety concept" is a description of the measures designed into the system, for example within
the electronic units, so as...