QC/T 1167-2022: Download Full-PDF & Invoice in 9 seconds.
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Excerpt from above true-PDF:
QC/T 1167-2022
QC
AUTOMOBILE INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 43.040.40
CCS T 24
Service brake dynamometer squeal noise test methods for
passenger cars
ISSUED ON: APRIL 08, 2022
IMPLEMENTED ON: OCTOBER 01, 2022
Issued by: Ministry of Industry and Information Technology of PRC
Table of Contents
Foreword ... 6
1 Scope ... 7
2 Normative references ... 7
3 Terms and definitions ... 7
4 Test equipment ... 9
5 Test fixture ... 11
6 Test requirements and instructions ... 13
7 Test preparation ... 15
8 Test method ... 17
9 Data processing ... 26
Appendix A (Normative) Description of each parameter in the braking test process . 29
Appendix B (Informative) Example of test result processing ... 33
Service brake dynamometer squeal noise test methods for
passenger cars
1 Scope
This document specifies the terms and definitions, test equipment, test fixtures, test-
related requirements and instructions, test preparation, test methods, test data
processing for the service brake dynamometer squeal noise test methods for passenger
cars.
This document is applicable to passenger cars, which are specified in GB/T 3730.1-
2001. The commercial vehicles, whose maximum design gross mass does not exceed 3
500 kg, can make reference to this standard.
2 Normative references
The contents of the following documents constitute the essential provisions of this
document through normative references in the text. Among them, for dated references,
only the version corresponding to the date is applicable to this document; for undated
references, the latest version (including all amendments) is applicable to this document.
GB/T 3730.1-2001 Motor vehicles and trailers - Types - Terms and definitions
GB/T 3785.1-2010 Electroacoustics - Sound level meters - Part 1: Specifications
GB/T 5620 Road vehicles - Vocabulary and definition for braking of automotive
vehicles and their trailers
GB/T 15173 Electroacoustics - Sound calibrators
3 Terms and definitions
The terms and definitions as defined in GB/T 5620, as well as the following terms and
definitions, apply to this document.
3.1
Unladen condition
The state of vehicle at which its curb weight is loaded with 110 kg.
Invariable input mode
During a braking process, the control method which keeps the pressure of the input
pipeline constant.
3.10
Invariable output mode
During a braking process, the control method where the braking torque output by
the tested brake is always kept constant.
3.11
Pressure profile mode
In the drag test, the input control method where the brake pressure is changed with
time as specified.
4 Test equipment
4.1 General requirements
The test bench shall have the test capabilities of invariable input mode, invariable output
mode, deceleration brake, parking brake, as well as the drag test capacity of invariable
input mode and pressure profile mode; meanwhile the drive motor shall have the ability
of forward and reverse rotation.
4.2 Control system
The control system shall be able to realize invariable input mode, pressure profile mode
or invariable output mode, etc. Its control shall meet the following requirements:
- The rate of increase and decrease of brake pressure shall not be less than 10 MPa/s;
the maximum brake pressure shall not be less than 16 MPa;
- When controlled by pressure profile mode, the deviation -- between the average
brake pressure control value and the target value (set value) -- shall not exceed
±0.025 MPa;
- Except for control by pressure profile mode, the brake pressure overshoot of other
tests is less than 0.1 MPa;
- When controlled by invariable output mode, the deviation -- between the braking
deceleration and the target value (set value) -- shall not exceed 0.5 m/s;
- During the drag test, the speed of the vehicle shall not be lower than 90% of the
specified speed.
4.3 Brake cooling system
The inner diameter of the cooling air pipe shall be Φ200 mm ~ 320 mm; the outlet shall
be 300 mm ~ 400 mm away from the outer diameter of the brake disc (or brake drum);
the cooling air flow rate at the outlet shall be 10 m/s. If necessary, the cooling air speed
shall be adjusted, to meet the background noise requirements, which are specified in
4.7. When the above requirements cannot be met, it can be implemented, according to
the negotiation between the supplier and the buyer; meanwhile the background noise
measurement value shall be recorded in the test report.
4.4 Environmental control system
4.4.1 During the standard test and fading test, the cooling air temperature shall be
controlled at 25 °C ± 5 °C. During the cold state test, the cooling air temperature shall
be controlled below 10 °C below the initial braking temperature.
4.4.2 When the cooling air temperature is above 0 °C, the relative humidity of the
cooling air shall be controlled within the range of 50% ± 10%. When the cooling air
temperature is 0 °C or below, only the cooling air temperature shall be controlled.
4.5 Data acquisition system
4.5.1 The data acquisition system shall have the functions of continuous recording and
real-time display.
4.5.2 The sampling frequency of the following parameters shall not be lower than 50
Hz:
- The spindle speed of the test bench;
- The brake pressure;
- The brake output torque.
4.5.3 The sampling frequency of the following parameters shall not be lower than 10
Hz:
- The temperature of the brake disc (or drum);
- Cooling air temperature, relative humidity (or absolute humidity), wind speed (or
flow rate).
4.6 Brake noise measurement system
4.6.1 The microphone, which is used for noise measurement, shall comply with the
requirements of level 2 and above, as specified in GB/T 3785.1-2010.
5.5 According to the type of test fixture, the following driving methods can be selected:
a) Drive through the flange;
b) Drive by wheel hub;
c) Drive directly by the main shaft.
5.6 The type and driving mode of the test fixture shall be recorded in the test report.
6 Test requirements and instructions
6.1 Brake initial temperature control
6.1.1 Brake temperature rise
6.1.1.1 Except for the fading test, when the brake temperature is lower than the required
initial braking temperature before the next braking, the temperature shall be raised by
dragging, according to the following conditions, until the brake temperature is more
than 5 °C higher than that of the next braking:
- When the difference -- between the actual temperature of the brake and the required
initial temperature of the brake -- is greater than 30 °C, the drag speed is the speed
corresponding to the vehicle speed of 50 km/h; the braking pressure is 2 MPa (disc
brake) or 3 MPa (drum brake);
- When the actual temperature of the brake is below 30 °C less than or equal to the
required initial brake temperature, the drag speed is the speed corresponding to the
vehicle speed of 25 km/h; the brake pressure is 1 MPa (disc brake) or 1.5 MPa
(drum brake).
6.1.1.2 For the fading test, when the brake temperature does not meet the requirements
of the initial brake temperature, it shall increase the temperature, by dragging at a speed
of 80 km/h and a brake pressure equivalent to a brake deceleration of 1.96 m/s2; the
drag time shall not exceed 20 s each time.
6.1.2 Brake cooling
When the brake temperature is 5 °C or higher than the initial braking temperature
required for the next braking, rotate the brake disc/brake drum, at a speed of 20 km/h,
until the difference -- between the brake temperature and the initial braking temperature
is less than 5 °C.
6.2 Fading test temperature
See Table 2 for the initial braking temperature of the fading test. Special circumstances
shall be determined, through negotiation between the supplier and the buyer, OR
µ - Friction coefficient;
M - Braking torque, in Newton meter (N • m);
p - Brake pressure, in megapascals (MPa);
p0 - The braking pressure required when the braking torque reaches 5 N • m, in
megapascals (MPa), which usually takes zero unless otherwise specified;
Ap - The area of the piston on one side of the caliper, in square millimeters (mm2);
r - The effective friction radius of the brake disc, in meters (m)
η - The braking efficiency, which takes 1, unless otherwise specified.
6.4 Efficiency factor of drum brake
The efficiency factor of the drum brake is calculated according to formula (3):
Where:
C* - Efficiency factor of drum brake;
p0 - The braking pressure required when the braking torque reaches 5 N • m, in
megapascal (MPa), which usually takes 0.5 MPa unless otherwise specified;
Ag - Piston area of brake wheel cylinder, in square millimeter (mm2);
d - Inner diameter of the brake drum, in meters (m).
7 Test preparation
7.1 Determination of test inertia
The test inertia is calculated according to formula (4) OR stipulated through negotiation
between the supplier and the buyer:
Where:
I - Brake test inertia, in grams square meters (kg • m2);
k - Mass distribution coefficient;
......