GB/T 44123-2024 PDF English
US$410.00 · In stock · Download in 9 secondsGB/T 44123-2024: Test methods of hydraulic braking systems for motor vehicles Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedureStatus: Valid
| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivery | Name of Chinese Standard | Status |
| GB/T 44123-2024 | English | 410 |
Add to Cart
|
0-9 seconds. Auto-delivery
|
Test methods of hydraulic braking systems for motor vehicles
| Valid |
Excerpted PDFs (Download full copy in 9 seconds upon purchase)PDF Preview: GB/T 44123-2024
GB/T 44123-2024: Test methods of hydraulic braking systems for motor vehicles---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT44123-2024
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 43.040.40
CCS T 24
Test Methods of Hydraulic Braking Systems for Motor
Vehicles
Issued on: MAY 28, 2024
Implemented on: SEPTEMBER 1, 2024
Issued by. State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword... 4
1 Scope... 5
2 Normative References... 5
3 Terms and Definitions... 5
4 Test Conditions... 5
4.1 Road Conditions... 5
4.2 Environmental Conditions... 6
4.3 Test Vehicle... 6
4.4 Test Equipment... 6
5 Test Methods... 7
5.1 General Requirements... 7
5.2 Preliminary Test and Static Inspection... 10
5.3 No-load Basic Performance Test... 10
5.4 Failure Performance Test... 10
5.5 Full-load Basic Performance Test... 10
5.6 Braking and Running Deviation Tests of Vehicles Equipped with Temporary Spare
wheel / tire... 10
5.7 Additional Test for Braking Systems with Auxiliary Energy... 11
5.8 Test Data Processing... 11
Appendix A (normative) Preliminary Test and Static Inspection... 12
A.1 Component Inspection... 12
A.2 Braking System Operation Inspection... 12
A.3 Alarm Signal Inspection... 12
A.4 Pipeline Pressure Relation Inspection... 13
A.5 Additional Inspection of Service Braking System with Electronic Control
Transmission Device... 13
Appendix B (normative) No-load Basic Performance Test... 15
B.1 Cold State Performance (O-type) Test of Service Brakes with Power Disengaged.. 15
B.2 Cold State Performance (O-type) Test of Service Brakes with Power Engaged... 15
Appendix C (normative) Failure Performance Test... 17
C.1 General Requirements... 17
C.2 Circuit Failure Test... 17
C.3 Assistance Failure Test... 18
Test Methods of Hydraulic Braking Systems for Motor
Vehicles
1 Scope
This document specifies the test conditions and test methods of hydraulic braking systems for
motor vehicles.
This document is applicable to Category-M and Category-N vehicles with hydraulic braking
systems as specified in GB/T 15089.
2 Normative References
The contents of the following documents constitute indispensable clauses of this document
through the normative references in the text. In terms of references with a specified date, only
versions with a specified date are applicable to this document. In terms of references without a
specified date, the latest version (including all the modifications) is applicable to this document.
GB/T 5620 Road Vehicles - Braking of Automotive Vehicles and Their Trailers - Vocabulary
GB/T 8170 Rules of Rounding off for Numerical Values & Expression and Judgement of
Limiting Values
GB 12676 Technical Requirements and Testing Methods for Commercial Vehicle and Trailer
Braking Systems
GB/T 15089 Classification of Power-driven Vehicles and Trailers
GB 21670 Technical Requirements and Testing Methods for Passenger Car Braking Systems
3 Terms and Definitions
The terms and definitions defined in GB 12676, GB 21670, GB/T 5620 and GB/T 15089 are
applicable to this document.
4 Test Conditions
4.1 Road Conditions
4.1.1 Road surface
The test road surface shall be a straight, solid asphalt road surface or concrete road surface or
charged to the state of charge or first charged to above the state, and then, discharged
to a fixed load at a roughly constant power, until the corresponding state of charge is
reached. For vehicles powered only by power batteries, the state of charge can be
adjusted by driving the vehicle. For tests conducted with the power battery partially
charged, it is advisable to conduct them as soon as possible after the required state of
charge is reached.
5.1.10 For vehicles equipped with an electric regenerative braking system, the state
requirements for the electric regenerative braking system during the O-type test depend on the
type of the electric regenerative braking system. If the A-type electric regenerative braking
system has a separate control device, during the O-type test, the A-type electric regenerative
braking system shall not be enabled. The braking force generated by the B-type electric
regenerative braking system shall not exceed the minimum level guaranteed by the system
design, or the test shall be conducted without using the regenerative braking components. If the
power battery is in one of the following states of charge, then, it is considered to meet the
conditions.
a) The maximum state of charge recommended by the manufacturer in the vehicle
instruction manual;
b) If the manufacturer does not provide specific recommendations, the state of charge
shall not be less than 95%;
c) The highest level of state of charge that can be achieved by the vehicle’s automatic
control charging.
5.2 Preliminary Test and Static Inspection
Preliminary test and static inspection shall be carried out in accordance with Appendix A.
5.3 No-load Basic Performance Test
No-load basic performance test shall be carried out in accordance with Appendix B.
5.4 Failure Performance Test
The failure performance test shall be carried out in accordance with Appendix C.
5.5 Full-load Basic Performance Test
The full-load basic performance test shall be carried out in accordance with Appendix D.
5.6 Braking and Running Deviation Tests of Vehicles Equipped with Temporary
Spare wheel / tire
The braking and running deviation tests of Category-M1 and Category-N1 vehicles equipped
with temporary spare wheel / tire shall be carried out in accordance with Appendix E.
Appendix A
(normative)
Preliminary Test and Static Inspection
A.1 Component Inspection
A.1.1 Check the appearance of the braking system to confirm whether the braking system and
its components are correctly connected and reliably installed, and whether there is no leakage
or component interference that may affect safety.
A.1.2 Perform static operation of the service brake to check whether the service brake acts on
all wheels. By disassembling the pipeline, lifting and observing, etc., check and record the
layout of the hydraulic circuit.
A.2 Braking System Operation Inspection
A.2.1 Service braking system inspection
When the vehicle is stationary, and the driver wears a fixed seat belt and holds the steering
wheel with both hands, check whether the service brake control device can be actuated from
the driving position, and check whether the service brake and parking brake control devices are
independent of each other.
A.2.2 Parking brake system inspection
When the vehicle is stationary, and the driver wears a fixed seat belt, check whether the parking
brake control device can be actuated from the driving position.
A.2.3 Emergency braking system inspection
When the vehicle is stationary, and the driver wears a fixed seat belt and holds the steering
wheel with at least one hand (for Category-M1 vehicles, two hands are required), check whether
the emergency brake control device can be actuated at full stroke from the driving position.
A.3 Alarm Signal Inspection
A.3.1 For vehicles equipped with an anti-lock braking system (ABS), when the vehicle is
stationary and the anti-lock braking system is powered on after the vehicle is powered on, check
whether the yellow alarm signal is on and the system self-checks. If there is no fault, check
whether the alarm signal is off. Check whether the alarm signal is clearly visible during the day.
A.3.2 When the vehicle is stationary, by disconnecting the power supply line of the sensor,
disconnecting the external line of the controller and disconnecting the regulator circuit, etc.,
simulate different ABS electrical faults, and check whether an optical alarm signal is issued to
the driver and whether the alarm signal is clearly visible during the day.
A.4 Pipeline Pressure Relation Inspection
A.4.1 Relations between pipeline pressure and control force
When the vehicle is stationary, install a control force measuring device and a pipeline pressure
sensor on the vehicle and release the parking brake. Then, actuate the service brake control
device, and slowly increase the control force from 0 to the maximum allowable value (500 N
for Category-M1 vehicles and 700 N for other categories), and record the control force and
pipeline pressure curve. Check in the following two states.
a) Normal assistance state.
1) For vehicles that rely on the engine to provide vacuum assistance (intake
manifold or mechanical vacuum pump), increase the engine speed from idle to
above 50% of the rated speed, run 4 ~ 5 times, and then, carry out the test while
the engine is at idle speed;
2) For vehicles with vacuum assistance or hydraulic assistance of energy storage
devices, the energy level of the energy storage device shall be 90% of the
manufacturer’s recommended value;
3) For vehicles with electronic assistance, the power supply voltage shall be at the
manufacturer’s recommended value.
b) No assistance state.
A.4.2 Relations between pipeline pressure and time
A.4.2.1 The initial energy level is set in accordance with A.4.1 a).
A.4.2.2 When vehicle is stationary, quickly press the brake pedal. The service brake control
force increases rapidly from 0 to the maximum allowable value (500 N for Category-M1
vehicles and 700 N for other categories). The pedaling process is as fast as possible, but it
cannot significantly exceed the maximum allowable control force. Record the pressure growth
curve of each axle / wheel. The triggering moment of the service brake control device is used
as the starting point for evaluating the response time, and the pressure growth curve of the most
unfavorable axle / wheel is used to determine the static response time.
A.5 Additional Inspection of Service Braking System with Electronic Control
Transmission Device
A.5.1 When the vehicle is stationary, perform the following additional inspections on the
service braking system.
a) Release the parking brake, set the power device on/off control to the “ON” (“RUN”)
position, actuate the service brake, and record the pipeline pressure. The control force
for Category-M1 vehicles shall not exceed 500 N, and the control force for other
categories shall not exceed 700 N;
D.4 Type II Test
D.4.1 General requirements
D.4.1.1 This test is applicable to Category-M3 vehicles equipped with hydraulic (excluding air-
over-hydraulic) braking systems.
D.4.1.2 When the vehicle is fully loaded, the test is carried out using the method specified in
D.4.2.1 or D.4.2.2.The average speed deviation shall not exceed 5 km/h.
D.4.1.3 If the auxiliary braking system of the vehicle is a retarder and it cannot generate
sufficient braking force due to the influence of the driving distance during the test, the acting
force of the retarder can be gradually increased to maintain the specified speed.
D.4.1.4 If the auxiliary braking system of the vehicle is engine braking and it cannot generate
sufficient braking force, the driver of the test vehicle can assist in maintaining the specified
vehicle speed by adjusting the control force of the service braking system. If the service braking
system is used as assistance, after completing the ramp test / simulated ramp traction test, within
60 seconds and in accordance with the test conditions specified in Table B.1, the O-type test
with power disengaged shall be carried out.
D.4.2 Test methods
D.4.2.1 Ramp test
Only use the auxiliary braking system to brake, and continuously drive downhill at an average
vehicle speed of 30 km/h on a 6% ramp for 6 km. The selected gear shall ensure that the power
unit revolution speed does not exceed the maximum revolution speed specified by the vehicle
manufacturer.
D.4.2.2 Simulated ramp traction test
Use a tractor equipped with a tension gauge and traction device to tow the vehicle for 6 km at
an average vehicle speed of 30 km/h and only use the auxiliary braking system to balance the
tensile force of the tractor.
The braking force of the auxiliary braking system and the traction force of the tractor shall be
coordinated to keep the vehicle moving at a uniform speed of 30 km/h, and the traction force
shall be equivalent to 6% of the total mass of the test vehicle. In order to ensure the effectiveness
of the test, the traction force shall not be less than 4% of the total mass of the test vehicle at any
time. During the test, record the vehicle speed and traction force.
D.5 Parking Brake System Test
D.5.1 Static test
D.5.1.1 Through the service brake, put a fully loaded vehicle in a stationary state on an 18%
ramp (20% ramp for Category-M1 vehicles) and keep it in a downhill state. Put the transmission
in neutral or N gear, apply the parking brake, record the maximum control force during the test,
release the service brake, and keep it stationary for at least 5 minutes. The maximum control
force applied during the test shall not exceed 600 N (for hand control device) or 700 N (for foot
control device) [for Category-M1 vehicles, the control force shall not exceed 400 N (for hand
control device) or 500 N (for foot control device)]. This test allows the parking brake to be
operated multiple times to achieve the required parking brake holding force, but the control
force of each operation shall be within the specified range.
D.5.1.2 Maintain the uphill state on the ramp and test in accordance with D.5.1.1.
D.5.1.3 For vehicles that are allowed to be coupled to unbraked trailers, additional tests shall
be conducted using one of the following methods.
a) Actual vehicle method (recommended method). the train reaches the maximum
design total mass by coupling a suitable trailer, and the test is conducted on a 12%
ramp in accordance with D.5.1.1 and D.5.1.2;
b) Simulation method. the ramp required for the simulation test is the slope
corresponding to the ratio of the maximum design total mass of the train to the main
vehicle multiplied by 12%. If there is no suitable ramp, a steeper ramp close to the
slope shall be selected, and the test shall be conducted in accordance with D.5.1.1 and
D.5.1.2.
D.5.1.4 If there is no suitable ramp to conduct the tests described in D.5.1.1 ~ D.5.1.3, the
parking brake performance can be checked by traction test on a horizontal road surface to
simulate the ramp parking brake. connect the front end of the vehicle to the tractor, apply the
parking brake, then, start the tractor and slowly apply traction force, until the vehicle shows a
tendency to move, and record the traction force. Then, connect the rear end of the vehicle to the
tractor, drag the vehicle in the reverse direction for testing, and record the traction force.
D.5.2 Dynamic test
When the vehicle is fully loaded, at an initial test vehicle speed of 30 km/h in neutral or N gear,
use the parking brake to brake once. The control force shall not exceed the limit required for
the corresponding vehicle model in D.5.1.1.Record the control force, vehicle speed and braking
deceleration.
D.5.3 Additional test for vehicles equipped with electronic control transmission parking
brake system
D.5.3.1 Simulate an electrical failure of the control device, or a damage of the internal wiring
(excluding the power supply line) of the electronic control transmission connecting the control
device and the electronic control unit (ECU), and on an 8% up and down ramp, in accordance
with D.5.1.1 and D.5.1.2, carry out the test. For vehicles with automatic parking function in
stationary state, the following inspections shall also be carried out.
---When the ignition (start) switch is turned off, check whether the parking brake is still
separate control device, the device shall not be used during the test.
D.6.2.3 For vehicles equipped with a B-type electric regenerative braking system, if the
specified vehicle speed cannot be reached within the cycle, a thermal state performance test
shall be performed at the highest vehicle speed that can be achieved after the heating cycle. For
comparison, Category-M1 vehicles shall also be subject to an O-type test with power disengaged
at full load at the same vehicle speed after completing the recovery performance test.
D.6.3 Recovery performance test
D.6.3.1 Recovery process
For Category-M1 vehicles, after the thermal state performance test is completely, immediately
accelerate to 50 km/h in the shortest possible time, use the highest gear that is suitable for the
vehicle speed, and at an average deceleration of 3 m/s2, perform service braking. After the
braking, immediately accelerate to 50 km/h in the shortest possible time and maintain the
vehicle speed; at a position of 1.5 km away from the starting point of the last braking, at a
deceleration of 3 m/s2, brake again. Repeat this process, until the total number of braking times
reaches 4 times.
D.6.3.2 Recovery performance
After the last braking in the recovery process is completely, immediately accelerate to the test
vehicle speed specified in Table B.1 in the shortest possible time and perform the O-type test
with power disengaged. The average control force used shall not exceed the control force
actually used in the O-type test at full load.
D.6.4 Cold state inspection
Let the brakes cool to ambient temperature and check whether the brakes are binding. For
vehicles equipped with automatic wear compensation devices, the hottest brakes shall be cooled
down to below 100 °C, and the wheels shall be checked to see if they can freely rotate. For
vehicles other than Category-M1, if any wheels cannot be manually turned due to brake
resistance, measure the temperature of the brakes, then, drive the vehicle at a constant speed of
60 km/h for 1 km ~ 2 km, measure the temperature of the brakes again, and record the
temperature rise of the brakes.
Appendix F
(normative)
Additional Test for Braking Systems with Auxiliary Energy
F.1 General Requirements
F.1.1 In accordance with the information provided by the manufacturer, confirm the type of
vehicle assistance / powered braking system. For vehicles that must use auxiliary energy to
achieve emergency braking performance, in accordance with the methods in this Appendix,
perform additional energy storage inspection tests.
F.1.2 During the test, the parking brake must be released, and confirm that the brake clearance
of all wheels is adjusted to the smallest possible size, while ensuring that the wheels can be
manually turned.
F.2 Vacuum Assistance System
F.2.1 Vacuum extraction capability
F.2.1.1 Test conditions
If the vacuum source is the vacuum generated by the engine, the test shall be performed at the
engine idle speed defined by the vehicle manufacturer.
If the vacuum source is a vacuum pump driven by the engine, the test shall be performed at 65%
of the maximum power speed of the engine. If the revolution speed of the engine is limited
when the vehicle is stationary, then, the test shall be performed at 65% of the manufacturer’s
limited speed.
If the vacuum source is an electric vacuum pump, the test shall be performed at the rated power
supply voltage specified by the vehicle manufacturer.
F.2.1.2 Test method
The vehicle is stationary, and the transmission is in neutral or N gear. Before starting the power
unit, repeatedly step on the brake pedal, until the vacuum is zero. Then, start the power unit,
and under the conditions specified in F.2.1.1, measure the time to reach the vacuum pressure
specified by the manufacturer that can satisfy the vehicle’s service braking performance under
full load.
F.2.2 Capacity of energy storage device
F.2.2.1 Test conditions
The initial vacuum in the energy storage device shall comply with the vehicle manufacturer’s
provisions, but it shall not exceed 90% of the maximum vacuum.
The energy storage device shall not be replenished during the test, and all additional devices
and associated accumulators shall be disconnected.
F.2.2.2 Test method
The vehicle is stationary, the transmission is in neutral or N gear, and the ignition / start switch
is turned off. If an additional accumulator is installed, disconnect the connection between the
additional accumulator and its energy supply equipment.
If the vacuum source is a vacuum pump, fully actuate the service brake for 8 times, then, with
the vacuum source disconnected, perform an emergency braking test at the initial test vehicle
speed and control force specified in Table C.1, and record the initial braking speed, control
force, deceleration, braking distance and vehicle stability.
If the vacuum source is an engine, fully actuate the service brake for 4 times, then, with the
vacuum source disconnected, perform an emergency braking test at the initial test vehicle speed
and control force specified in Table C.1, and record the initial braking speed, control force,
deceleration, braking distance and vehicle stability.
F.2.3 Low vacuum alarm test
Release system energy to the alarm vacuum threshold and check whether the alarm device emits
an optical or acoustic alarm signal when the vacuum is significantly reduced. With the vacuum
source disconnected, carry out 4 full braking operations. Then, in accordance with the initial
test vehicle speed and control force specified in Table C.1, carry out an emergency braking test,
and record the initial braking speed, control force, deceleration, braking distance and vehicle
stability.
F.3 Hydraulic Assistance System
F.3.1 Energy supply capacity
F.3.1.1 Test conditions
During the test, the energy storage device of the auxiliary equipment shall not be disconnected
(except for automatic disconnection).
If the energy comes from the engine, the energy shall be supplied at the maximum power speed
of the engine or at the speed allowed by the speed limiter (if equipped).
If the energy comes from a motor-driven hydraulic pump, the test shall be carried out at the
rated supply voltage specified by the vehicle manufacturer.
F.3.1.2 Test method
The vehicle is stationary, and the transmission is in neutral or N gear. Without replenishing
shall not exceed the energy supply cut-in pressure.
The energy storage device shall not be replenished during the test, and any additional devices
and associated accumulators shall be disconnected.
The frequency of fully actuated braking operations shall ensure that there is a time interval of
at least 60 seconds between each operation, and each actuation shall be maintained for 20 s ~
30 s.
F.4.2.2 Test method
The vehicle is stationary, the transmission is in neutral or N gear, and the energy supply device
is disconnected. Starting from the accumulator pressure level specified by the manufacturer that
does not exceed the energy supply cut-in pressure, fully actuate the service brake for 8 times.
Then, at the initial speed specified in Table C.1, perform an emergency braking test, and record
the initial braking speed, control force, deceleration, braking distance and vehicle stability.
F.4.3 Hydraulic transmission failure
F.4.3.1 General
If the hydraulic braking system has only one hydraulic pump to supply energy to two
accumulators, a hydraulic transmission failure test is required. If the system has two hydraulic
pumps driving two completely independent circuits, when one circuit fails, the other circuit can
normally work, then, this test is not required.
F.4.3.2 Test method
Before the test, it shall first be checked through the information provided by the manufacturer
whether a leakage fault in one transmission circuit will prevent the shared hydraulic pump from
supplying energy to the other circuit.
At the most unfavorable position of a hydraulic transmission circuit, simulate a failure.
Disconnect the auxiliary equipment and the associated accumulator and adjust the accumulator
pressure to the level specified by the manufacturer, but it shall not exceed the hydraulic pump
cut-in pressure. When the hydraulic pump is not in operation or the engine is idling, the
following tests shall be conducted.
a) If a leakage fault in one transmission circuit will prevent the shared hydraulic pump
from supplying energy to the other circuit, then, fully actuate the service brake for 8
times and record the pipeline pressure at the 9th actuation;
b) If a leakage fault in one transmission circuit will not prevent the shared hydraulic
pump from supplying energy to the other circuit, then, fully actuate the service brake
for 4 times and record the pipeline pressure at the 5th actuation.
If there are multiple positions for the selection of the most unfavorable position of the simulated
failure and it is impossible to accurately judge, then, each position is tested.
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
Tips & Frequently Asked QuestionsQuestion 1: How long will the true-PDF of English version of GB/T 44123-2024 be delivered?Answer: The full copy PDF of English version of GB/T 44123-2024 can be downloaded in 9 seconds, and it will also be emailed to you in 9 seconds (double mechanisms to ensure the delivery reliably), with PDF-invoice. Question 2: Can I share the purchased PDF of GB/T 44123-2024_English with my colleagues?Answer: Yes. The purchased PDF of GB/T 44123-2024_English will be deemed to be sold to your employer/organization who actually paid for it, including your colleagues and your employer's intranet. Question 3: Does the price include tax/VAT?Answer: Yes. Our tax invoice, downloaded/delivered in 9 seconds, includes all tax/VAT and complies with 100+ countries' tax regulations (tax exempted in 100+ countries) -- See Avoidance of Double Taxation Agreements (DTAs): List of DTAs signed between Singapore and 100+ countriesQuestion 4: Do you accept my currency other than USD?Answer: Yes. www.ChineseStandard.us -- GB/T 44123-2024 -- Click this link and select your country/currency to pay, the exact amount in your currency will be printed on the invoice. Full PDF will also be downloaded/emailed in 9 seconds. How to buy and download a true PDF of English version of GB/T 44123-2024?A step-by-step guide to download PDF of GB/T 44123-2024_EnglishStep 1: Visit website https://www.ChineseStandard.net (Pay in USD), or https://www.ChineseStandard.us (Pay in any currencies such as Euro, KRW, JPY, AUD).
Step 2: Search keyword "GB/T 44123-2024".
Step 3: Click "Add to Cart". If multiple PDFs are required, repeat steps 2 and 3 to add up to 12 PDFs to cart.
Step 4: Select payment option (Via payment agents Stripe or PayPal).
Step 5: Customize Tax Invoice -- Fill up your email etc.
Step 6: Click "Checkout".
Step 7: Make payment by credit card, PayPal, Google Pay etc. After the payment is completed and in 9 seconds, you will receive 2 emails attached with the purchased PDFs and PDF-invoice, respectively.
Step 8: Optional -- Go to download PDF.
Step 9: Optional -- Click Open/Download PDF to download PDFs and invoice.
See screenshots for above steps: Steps 1~3 Steps 4~6 Step 7 Step 8 Step 9
|