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GB 1495-2002: Limits and measurement methods for noise emitted by accelerating motor vehicles
GB 1495-2002
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 13.140
Z 32
Replacing GB 1495, partially replacing GB 1496-79
Limits and measurement methods for noise
emitted by accelerating motor vehicles
ISSUED ON. JANUARY 04, 2002
IMPLEMENTED ON. OCTOBER 01, 2002
Issued by. State Environmental Protection Administration;
General Administration of Quality Supervision, Inspection and
Quarantine.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Definitions ... 5 
4 Noise limit ... 6 
5 Measurement methods ... 7 
Annex A (standard) Measurement methods for noise emitted by accelerating
motor vehicles ... 8 
Annex AA Requirements for noise measurement test road ... 15 
Annex AB Record of measurement for noise emitted by accelerating motor
vehicles ... 23 
Limits and measurement methods for noise
emitted by accelerating motor vehicles
1 Scope
This Standard specifies the limits for noise emitted by accelerating new
produced motor vehicles.
This Standard specifies the measurement methods for noise emitted by
accelerating new produced motor vehicles.
This Standard is applicable to Category-M and Category-N1 motor vehicles.
2 Normative references
The following standards contain the provisions which, through reference in this
Standard, constitute the provisions of this Standard. For dated references,
subsequent amendments (excluding corrections) or revisions do not apply to
this Standard. However, the parties who enter into agreement based on this
Standard are encouraged to investigate whether the latest versions of these
documents are applicable.
GB 3785-83, Electroacoustics - Sound level meters
GB/T 15173-94, Sound calibrators
GB/T 12534-90, Motor vehicles - General rules of road test method
ISO 10844-1994, Acoustics - Specification of test tracks for the purpose of
measuring noise emitted by road vehicles 2
ISO 10534 1996, Acoustics - Determination of sound absorption coefficient
and impedance in impedance tubes - Part 1. Method using standing wave
ratio 3
GB/T 17692-1999, Measurement methods of net power for automotive
engines
1 The classification for motor vehicles is in accordance with GB/T 15089-1994 “Classification of power-
driven vehicles and trailers”.
2 This Standard is under the jurisdiction of National Technical Committee on Acoustics of Standardization
Administration of China.
3 This Standard is under the jurisdiction of National Technical Committee on Acoustics of Standardization
Administration of China.
3 Definitions
For the purposes of this document, the following definitions apply.
3.1 Motor vehicle’s category
In terms of noise outside the motor vehicle, a category of motor vehicle refers
to a category of motor vehicles that have no difference in the following main
aspects.
3.1.1 Body shape or structural material (especially the engine compartment and
its sound insulation material).
3.1.2 Length and width of motor vehicle.
3.1.3 Engine type (ignition or compression ignition, two-stroke or four-stroke,
reciprocating or rotary piston), number of cylinders and displacement, number
of carburetor and type or fuel injection system type, valve arrangement, rated
power and corresponding speed; or the category of drive motor (for electric
vehicles).
3.1.4 Drive train, gear number and its speed ratio.
3.1.5 Noise reduction system or components as defined in 3.2 and 3.3 below.
3.1.6 For vehicles other than Category-M1 and Category-N1, if the difference
between 3.1.2 and 3.1.4 does not result in a change in the noise measurement
method (such as gear selection), the engine of the same type and (or) when
the total transmission ratio is different, it can be regarded as the same category.
3.2 Noise reduction system
Noise reduction system refers to the complete set of components necessary to
limit the motor vehicle and its exhaust noise. When the noise reduction
component’s designations or trademarks in the system are different, or the size
and shape of the components, material properties, assembly, working principle
are different, or the number of intake/exhaust mufflers is different, the system
shall be regarded as different types of noise reduction systems.
3.3 Noise reduction system components
The noise reduction system component refers to one of the individual
components that constitute the noise reduction system, such as the exhaust
pipe, the expansion chamber, the muffler, etc. It is considered a component of
the noise reduction system when the presence of the air filter is essential to
ensure that the specified noise limits are met. The exhaust manifold shall not
be considered as a component of the noise reduction system.
Annex A
(Normative)
Measurement methods for noise emitted by accelerating motor vehicles
A.1 Measuring instruments
A.1.1 Acoustic measurement
A.1.1.1 The sound level meter for measurement or other equivalent
measurement system shall not be lower than the requirements of the Type 1
sound level meter specified in GB 3785. “A” frequency weighting characteristics
and “F” time weighting characteristics shall be used for measurement. When
using a system that automatically samples and measures the A-weighted sound
level, the reading interval shall not exceed 30 ms.
A.1.1.2 Before and after measurement, the sound level meter must be
calibrated according to the manufacturer's specifications with a Level 1 acoustic
calibrator in accordance with GB/T 15173. If no adjustment is made, if the
difference between the previous calibration reading and the previous calibration
reading exceeds 0.5 dB, the measurement result after the previous calibration
is considered invalid. The readings during calibration shall be recorded in the
form in Annex AB.
A.1.2 Measurements of rotating speed, vehicle speed
An engine tachometer or vehicle speed measuring instrument with an accuracy
better than ±2% must be used to monitor the rotating speed or vehicle speed.
Do not use the same type of instrument on the vehicle.
A.1.3 Meteorological parameter measurement
The accuracy of the thermometer shall be within ±1°C. The accuracy of the
anemometer shall be within ±1.0 m/s.
A.1.4 All measuring instruments shall be periodically inspected in accordance
with the relevant national standards for measuring instruments.
A.2 Measuring conditions
A.2.1 Measuring site
A.2.1.1 The sound field conditions that shall be achieved at the measuring site
(see Figure 1) are. when placing a non-directional small sound source at the
center of the site (point O), the sound level deviation in all directions on the
hemisphere does not exceed ±1dB. If the following conditions are met, the
venue can be considered to have reached this sound field condition.
a) there are no large acoustic reflectors, such as fences, rocks, bridges or
buildings, within a radius of 50m based on the center of the measurement
site (point O);
b) the surface of the test road and the rest of the site are dry, and there is no
sound absorbing material such as snow, tall grass, loose soil or slag;
c) there are no obstacles affecting the sound field near the microphone, and
no one is standing between the sound source and the microphone; the
observer conducting the measurement shall also be in a position that does
not affect the measured value of the instrument.
A.2.1.2 The measurement site shall be substantially horizontal, so...