1 Scope
This standard specifies the structure, performance and test methods for braking system of passenger cars (vehicle).
This standard is applicable to vehicles of categories M1 specified by GB/T 15089.
2 Normative References
The following standards contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent amendments (excluding amending error in the text) to, or revisions of, any of these publications do not be applied. However, the parties whose enter into agreement according to these specifications are encouraged to research whether the latest editions of these references are applied or not. For undated references, the latest edition of the normative document is applicable to these specifications.
GB 4094 Motor Vehicles-Symbols for Controls, Indicators and Tell-tales [GB 4094-1999, eqv 93/91/EEC (78/316/EEC)]
GB/T 5620 Road vehicles -- Braking of automotive vehicles and their trailers -- Vocabulary (GB/T 5620-2002, idt ISO 611: 1994)
GB 12981 Motor vehicle brake fluids (GB 12981-2003, ISO 4925: 1978, MOD)
GB/T 14168 Motor vehicles -- Graphical symbols to designate brake fluid types (GB/T 14168-1993, eqv ISO 9128: 1987)
GB/T 15089 Classification of Power-driven Vehicles and Trailers
GB/T 17619 Limits and methods of testing for immunity of electrical / electronic sub-assemblies in vehicles to electromagnetic radiation
GB 18655 Vehicles boats and internal combustion engines -- Radio disturbance characteristics -- Limits and methods of measurement for the protection of on-board receivers (GB 18655-2002, idt IEC/CISPR 25: 1995)
3 Terms and Definitions
For the purposes of this document, the terms and definitions in GB/T 5620 together with the follows apply.
3.1 Basic Terms and Definitions
3.1.1
Vehicle type
A category of vehicles which do not differ in such essential respects as:
——the maximum total design mass;
——the distribution of mass among the axles;
——The highest design speed;
——The type of braking equipment, with more particular reference to the presence or otherwise of equipment for braking a trailer or any presence of electric braking system;
——The number of and layout of axles;
——The type of engine;
——The gear and speed ratio of transmission;
——The final drive ratios;
——The tyre dimensions.
3.1.2
Braking equipment
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 equipment consists of the control device, the transmission device, and the brake proper.
3.1.3
Control device
The part actuated directly by the driver to furnish to the transmission the energy required for braking or controlling it. This energy may be the muscular energy of the driver, or energy from another source controlled by the driver, or a combination of these various kinds of energy.
3.1.4
Transmission device
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 storage of energy (energy accumulator) in the system is likewise part of the transmission.
The transmission device 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'.
3.1.4.1
Control transmission device
The combination of the components of the transmission device which control the operation of the brakes, including the control function and the necessary storage(s) of energy.
3.1.4.2
Energy transmission device
The combination of the components which supply to the brakes the necessary energy for their function, including the storage(s) of energy necessary for the operation of the brakes.
3.1.5
Brake
The part in which the forces opposing the movement of the vehicle develop. It may be a friction brake (when the forces are generated by friction between two parts of the vehicle moving relatively to one another); an electrical brake (when the forces are generated by electro-magnetic action between two parts of the vehicle moving relatively to, but not in contact with one another); a fluid brake (when the forces are generated by the action of a fluid situated between two parts of the vehicle moving relatively to one another); or an engine brake (when the forces are derived from an artificial increase in the braking action, transmitted to the wheels, of the engine).
3.1.6
Different types of braking equipment
Equipment which differ in such essential respects as:
——Components having different characteristics;
——A component made of materials having different characteristics, or a component differing in shape or size;
——A different assembly of the components.
3.1.7
Component of the braking equipment
One of the individual parts which, when assembled, constitutes the braking equipment.
3.1.8
Progressive and graduated braking / modulatable braking
Braking during which, within the normal operating range of the device, and during actuation of the brakes, whose the braking force varies proportionally as the action on the control (monotonic function) and can be easily regulated with sufficient precision;
3.1.9
Unladen condition
The mass of a complete vehicle, adding with 110 kg.
3.1.10
Laden condition
Except where otherwise stated, a vehicle so laden as to attain its ‘maximum design total mass’.
3.1.11
The distribution of mass among the axles
The distribution of the effect of the gravity on the mass of the vehicle and/or its contents among the axles.
3.1.12
Wheel/axle load
The vertical static reactive (force) of the road surface in the contact area on the wheel/wheels of the axle.
3.1.13
Maximum stationary wheel/axle load
The stationary wheel/axle load achieved under the condition of the laden vehicle.
3.1.14
Hydraulic braking equipment with stored energy
A braking equipment where energy is supplied by a hydraulic fluid under pressure, stored in one or more accumulator(s) fed from one or more pressure pump(s), each fitted with a means of limiting the pressure to a maximum value. This value shall be specified by the manufacturer.
3.1.15
Actuation
Application and release of the control.
3.1.16
Electric regenerative braking, EBS
A braking system which, during deceleration, provides for the conversion of vehicle kinetic energy into electrical energy.
3.1.16.1
Electric regenerative braking control
A device which modulates the action of the electric regenerative braking system.
3.1.16.2
Electric regenerative braking of category A
An electric regenerative braking system which is not part of the service braking system.
3.1.16.3
Electric regenerative braking of category B
An electric regenerative braking system which is part of the service braking system.
3.1.17
Traction battery; power battery
An assembly of accumulators (batteries) constituting the storage of energy used for powering the traction motor(s) of the vehicle.
3.1.18
Electric state of charge, SOC
The instantaneous ratio of electric quantity of energy stored in the traction battery relative to the maximum quantity of electric energy which could be stored in this battery.
3.1.19
Phased braking
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.
3.1.20
Automatically commanded braking
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.
3.1.21
selective braking
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.
3.1.22
Nominal value
The reference braking performance gained by assigning the values to the input and output transfer functions of the braking system, which can be demonstrated the relation of the braking strength generated by the vehicle self and the braking input variable level.
3.1.23
Wheel locking
The duration time is larger than or equal to 100ms where a vehicle runs at a speed of over 15 km/h and the rotational speed of wheels is zero or the slip rate is 100%; such time, for ABS test conducted on pavement with low coefficient of adhesion, is 500 ms.
3.1.24
Yaw angle
Included angle formed by the central line and the running reference line when a vehicle stops running.
3.1.25
Antilock braking system, ABS
A system, in braking process, that control sliding degrees of wheel(s) at its rotation direction by automatic means.
3.1.26
Sensor
A component that is used to identify motion state of vehicle or rotation state of wheel(s), and transfer to this information to the controller.
3.1.27
Controller
A component that is used to treat the information provided by the sensor and send the command to the modulator.
3.1.28
Modulator
A component that is used to adjust brake pressure (generating brake force) as commanded by the command.
3.1.29
Directly controlled wheel )
Wheels whose brake force is adjusted by at least the data provided by the sensor of itself.
3.1.30
Indirectly controlled wheel 1)
Wheels whose brake force is adjusted by at least the data provided by the sensor of other wheel(s).
3.1.31
Full cycling
Anti-lock system repeats adjusting brake force to prevent locking directly controlled wheel. The case that only one adjustment is carried out from braking to stopping does not conform to this definition.
3.1.32
Cut-in pressure
The working pressure of the system where the energy storage device is connected with the energy source to supply energy.
3.1.33
Cut-out pressure
Working pressure of the system where the energy storage device is disconnected with the energy source cut off supply energy.
3.2 Terms and Definitions for Complex Electronic Vehicle Control System
3.2.1
Safety concept
The measures designed into the system, for example within the electronic units, so as to address system integrity and thereby ensure safe operation even in the event of an electrical failure.
3.2.2
Electronic control system
Unit assembly to realize preset vehicle control functions by electronic data processing and cooperation. This system generally consists of software control, and other independent functional devices including sensor, electronic control unit (ECU) and actuating apparatus. Such system may include mechanical, electronic-pneumatic, and electronic-hydraulic elements.
3.2.3
Complex electronic vehicle control system
Electronic control systems which are subject to a hierarchy of control in which a controlled function may be over-ridden by a higher level electronic control system/ function.
3.2.4
Higher-level control
Systems/functions are those which employ additional processing and/or sensing provisions to modify vehicle behavior by commanding variations in the normal function(s) of the vehicle control system.
