PDF GB/T 36986-2018 English
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Dynamic testing methods of brake performance for automobiles
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GB/T 36986-2018: PDF in English (GBT 36986-2018) GB/T 36986-2018
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 43.180
R 86
Dynamic testing methods of
brake performance for automobiles
ISSUED ON. DECEMBER 28, 2018
IMPLEMENTED ON. JULY 01, 2019
Issued by. State Administration for Market Regulation;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 4
4 Technical conditions for dynamic testing methods of brake performance for
automobiles... 5
5 Dynamic testing methods of brake performance for automobiles ... 7
Annex A (informative) Record sheet of testing on the road ... 13
Annex B (informative) Record sheet of testing by platform ... 15
Bibliography ... 17
Dynamic testing methods of
brake performance for automobiles
1 Scope
This Standard specifies the technical conditions and methods for the
automobile inspection agency to perform dynamic detection of the brake
performance of the automobiles in use.
This Standard is applicable to the dynamic testing and verification of brake
performance for automobiles.
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 7258, Safety specifications for power-driven vehicles operating on roads
GB/T 18314, Specifications for global positioning system (GPS) surveys
GB 21861-2014, Items and methods of motor vehicles safety technology
inspection
GB/T 28529, Platform brake tester
GB/T 28945, Portable braking performance tester for vehicles
JJF 1168, Calibration Specification for Portable Braking Performance Tester
for Motor Vehicle
JJF 1193, Calibration Specification for Non-contact Automotive
Speedometer
JJG 1020, Platform Brake Testers
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
pressure gauge shall be no more than 750kPa;
e) Brake pedal force for hydraulic braking. passenger vehicle with a seat
number of not more than 9 seats shall be no more than 400N; other
vehicles shall be no more than 450N.
4.2 Technical conditions for testing on the road are as follows.
a) The test pavement shall be hard, clean, dry, flat cement or asphalt
pavement; the pavement adhesion coefficient shall not be less than 0.7;
the longitudinal slope of the pavement shall be no more than 1%; and the
pavement shall not have obvious damage, protrusions and depressions;
b) The test pavement length shall be no less than 100m and the width shall
be no less than 6m;
c) Test lane edge shall be drawn;
d) The wind speed shall not exceed 5m/s when testing;
e) Portable braking performance tester for dynamic testing of brake
performance for automobiles shall comply with the provisions of GB/T
28945; its main metrological performance indicators shall meet the
requirements of JJF 1168;
f) The main metrological performance of the non-contact speedometer for
dynamic testing of brake performance for automobiles shall meet the
requirements of JJF 1193;
g) The main technical performance of the GPS detection system for dynamic
testing of brake performance for automobiles shall meet the requirements
of GB/T 18314;
h) The test results in both directions of the test road shall meet the
requirements.
4.3 Technical conditions for testing by platform are as follows.
a) The flat brake test bench shall be selected according to the axle load of
the vehicle to be tested;
b) The surface of the flat brake inspection table shall be clean and free of
foreign matter and oil. The adhesion coefficient of the surface of the
platform shall not be less than 0.75;
c) The flat brake inspection station shall comply with the provisions of GB/T
28529, and its main measurement performance indicators shall meet the
requirements of JJG 1020;
a) Install the speed sensor in the proper position of the vehicle under test to
meet the working requirements and connect with the host.
b) Install the non-contact speedometer speed indicator in a position that is
easy for the driver to observe.
c) Install the pedal force gauge on the brake pedal and connect to the main
unit.
d) Operate the instrument, select the brake test mode and enter the test state.
e) The vehicle under test starts, accelerates along the midline of the test lane
to a slightly higher than the initial brake speed, and then sets the
transmission to neutral. Step on the brake pedal when taxiing to the
specified initial speed to stop the vehicle. Read the fully deduced average
deceleration, braking initial speed, braking distance, speed, pedal force
measured by the non-contact speedometer. And check if the vehicle has
exited the test lane edge.
f) If the difference between the detected initial braking speed and the
specified initial braking speed exceeds ±2km/h, the test result is invalid.
Or correct the measured braking distance according to formula (1).
Where,
S0 - Braking distance at the specified initial braking speed, in meters (m);
v0 - Specified initial braking speed, in kilometers per hour (km/h);
ve - Measured initial braking speed, in kilometers per hour (km/h);
Se - Measured braking distance, in meters (m).
5.1.2.3 The method of testing by using GPS technology is.
a) Install the pedal force gauge on the brake pedal and connect to the main
unit.
b) Select a base station GPS receiving subsystem for an open, undisturbed
location.
c) Set up a mobile station GPS receiving subsystem on the car under test.
d) Turn on the base station GPS receiving subsystem and the mobile station
GPS receiving subsystem to enter the test state.
5km/h~10km/h. After the transmission is in neutral (for the automatic
transmission, the vehicle can be in the "D" position), and it shall be straight
on the platform.
b) When the wheels being tested are all on the plate, the brakes are urgently
pressed to stop the vehicle. The wheel load of each wheel is measured
(the passenger vehicle and other vehicles with a total mass less than or
equal to 3500kg shall be dynamic wheel load, and the left and right sides
of the two-axle and three-axle vehicles can be counted according to one
wheel), the maximum wheel braking force, the value of the whole process
of the wheel braking force increase, etc. Calculate the braking rate,
unbalance rate, vehicle braking rate and other indicators of each axle.
c) Restart the vehicle and operate the parking brake operating device when
the parking brake axle of the vehicle is on the plate. Measure the parking
brake force value and calculate the parking brake rate.
d) When the vehicle brake stops, if the detected wheel has left the plate, the
brake test is invalid and shall be retested.
e) For vehicles with slow braking response, if necessary, connect the pedal
switch signal to check whether the brake coordination time meets the
requirements.
f) The vehicle shall be squared during the test and the steering wheel must
not be turned.
g) The inspector urgently steps on the brake pedal, and the action of stepping
on the brake pedal shall be as uniform as possible.
h) When the vehicle being inspected has been questioned by the flatbed test
and its test results are questioned, the road test shall be used to decide.
5.2.3 Testing parameter calculation and result processing
The relevant braking performance parameters are calculated as follows.
a) Shaft braking rate. for the measured sum of the maximum braking force
of the left and right wheels of the axle and the percentage of the shaft axle
load, for passenger vehicle and other axle loads of less than or equal to
3500kg, take the sum of the left and right wheel loads corresponding to
the maximum moments of the left and right wheel braking forces, take the
axis static axle load for other vehicles.
b) Brake imbalance rate. the end point of the value is obtained when the left
and right wheels of the coaxial axis are locked. If the left and right wheels
cannot reach the lock slip, the moment when the maximum braking force
Annex B
(informative)
Record sheet of testing by platform
Table B.1 gives the data sheet for testing methods by platform.
Table B.1 -- Data record of testing methods by platform
Testing
station
name
Pilot
Testing
No. Testing time Tester
Vehicle
type
Brand
model Recorder
Date of
initial
register
License plate No. Supervisor
Engine
No. Fuel type Reviewer
Driving
type Parking axle
Curb mass
(kg)
Testing data
Testing item One axis Two axes Vehicle Parking Remark
Wheel
load
(kg)
Left wheel
Right
wheel
Maximum
driving
force
(10N)
Left wheel
Right
wheel
Dynamic
wheel
load
(kg)
Left wheel
Right
wheel
Maximum difference of
braking force process
(10N)
No-load
brake
Driving
brake rate
(%)
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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