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GB/T 1859.2-2015 English PDF (GBT1859.2-2015)

GB/T 1859.2-2015 English PDF (GBT1859.2-2015)

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GB/T 1859.2-2015: Reciprocating internal combustion engines -- Measurement of sound power level using sound pressure -- Part 2: Survey method

This Part of GB/T 1859 specifies the measurement method for sound power level of reciprocating internal combustion engines - survey method. This Part is applicable to reciprocating internal combustion engines (unless otherwise specified, hereafter known as engines for short) in the scope of application of GB/T 6072.1, and other internal combustion engines to which no suitable standards apply.
GB/T 1859.2-2015
GB
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 27.020
J 93
Partially replacing GB/T 1859-2000
Reciprocating internal combustion engines -
Measurement of sound power level using sound
pressure - Part 2. Survey method
ISSUED ON. DECEMBER 10, 2015
IMPLEMENTED ON. JULY 1, 2016
Issued by. General Administration of Quality Supervision, Inspection and Quarantine of the PRC;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 4
Introduction ... 6
1 Scope ... 9
2 Normative references ... 9
3 Terms and definitions ... 9
4 Acoustic environment ... 12
4.1 General ... 12
4.2 Background noise criteria ... 13
4.3 Acoustic suitability criteria for test environment ... 13
5 Measuring instruments ... 13
5.1 General ... 13
5.2 Calibration ... 13
5.3 Use ... 14
6 Installation and working conditions ... 14
6.1 General ... 14
6.2 Installation conditions ... 14
6.3 Working conditions ... 15
7 Measurement ... 15
7.1 General ... 15
7.2 Measurement uncertainty ... 16
7.3 Reference box ... 16
7.4 Measurement distance ... 16
7.5 Measurement surface and area ... 16
7.6 Microphone position ... 17
7.7 Suitability criteria for microphone position ... 21
8 Calculation ... 21
8.1 General ... 21
8.2 Calculation of the standard deviation of average sound pressure level measured ... 21
8.3 Calculation of sound power level ... 22
9 Recording content ... 24
10 Report ... 25
Appendix A (Normative) Methods for appraisal of acoustic environment ... 26 Appendix B (Normative) Sound power level of reference meteorological
conditions ... 31
References ... 33
Foreword
GB/T 1859 ?€?Reciprocating internal combustion engines - Measurement of
sound power level using sound pressure?€? is divided into 4 parts.
- Part 1. Engineering method;
- Part 2. Survey method;
- Part 3. Precision methods for hemi-anechoic rooms;
- Part 4. Survey method using a reference sound source.
This Part is Part 2 of GB/T 1859.
This Part is drafted in accordance with the rules given in GB/T 1.1-2009. This Part replaces the survey method in GB/T 1859-2000 ?€?Reciprocating
internal combustion engines - Measurement of emitted airborne noise -
Engineering method and survey method?€?.
As compared with GB/T 1859-2000, the main technical changes of this Part are as follows.
- DELETE relevant content of ?€?engineering method?€?;
- ADD the clause of ?€?Terms and definitions?€?;
- MODIFY the provisions on ?€?Acoustic environment?€?;
- ADD provisions on ?€?Measuring instruments?€?;
- MODIFY and ADD the provisions on ?€?Installation and working conditions?€?; - MODIFY and ADD the provisions on ?€?Measurement?€?;
- ADD the provisions on ?€?Calculation?€?;
- ADD the clause of ?€?Recording content?€?;
- MODIFY the provisions on ?€?Report?€?;
- DELETE Appendix A and Appendix B in GB/T 1859-2000;
- ADD Appendix A (Normative) ?€?Methods for appraisal of acoustic
environment?€? and Appendix B ?€?Sound power level of standard reference
conditions?€?.
Introduction
This Part of GB/T 1859 is one of a series of standards for the measurement of sound power level of reciprocating internal combustion engines using sound pressure. This series of standards gives a method for measuring the sound pressure level on the measurement surface enveloping sound source to
calculate the sound power level.
The measurement result of sound power level is basically irrelevant to the test environment and the installation conditions of sound source. This is an important reason for the use of sound power level to characterize the noise radiation of various types of machines and equipment.
The sound power level has the following uses.
- Marking of machine radiation noise under specified conditions;
- Verification of noise marking values;
- Comparison of radiation noise of machines of various models and
dimensions;
- Comparison with the noise limits specified in the purchase contract or specification;
- Development of engineering measures to reduce machine radiation noise (Generally, the band sound power level shall also be provided);
- Prediction of noise sound pressure level at specified position.
Table 1 shows the measurement methods of sound power level of three
accuracy classes to which the envelope surface method of this series of standards applies. The measurement results are accurate to 0.1 dB. The
methods given in this Part allow the determination of A-weighted sound power level; the accuracy class is Class 3.
Reciprocating internal combustion engines -
Measurement of sound power level using sound
pressure - Part 2. Survey method
1 Scope
This Part of GB/T 1859 specifies the measurement method for sound power level of reciprocating internal combustion engines - survey method.
This Part is applicable to reciprocating internal combustion engines (unless otherwise specified, hereafter known as engines for short) in the scope of application of GB/T 6072.1, and other internal combustion engines to which no suitable standards apply.
2 Normative references
The following documents are indispensable for the application of this document. For the dated references, only the versions with the dates indicated are applicable to this document. For the undated references, the latest version (including all the amendments) are applicable to this document.
GB/T 3785.1 Electroacoustics - Sound level meters - Part 1. Specifications GB/T 4129 Acoustics - Requirements for the performance and calibration o reference sound sources used for determination of sound power levels
GB/T 6072.1 Reciprocating internal combustion engines - Performance -
Part 1. Declarations of power, fuel and lubricating oil consumptions and test methods - Additional requirements for engines for general use
GB/T 6072.3 Reciprocating internal combustion engines - Performance -
Part 3. Test measurements
GB/T 15173 Electroacoustics - Sound calibrators
3 Terms and definitions
What defined in GB/T 3785.1, GB/T 6072.1 and the following terms and
One or more operating period or operating cycle of the sound source being measured used to determine the time-averaged sound pressure level, in
seconds (s).
3.6 Acoustic free field
An acoustic field where edge effect is negligible in homogeneous, isotropic media.
Note. The actual acoustic free field is an acoustic field where the reflection of edge or other objects within the frequency range of interest is negligible.
3.7 Reflecting plane
A flat surface for sound reflection on which the sound source being measured is located.
3.8 Acoustic free field over a reflecting plane
The acoustic free field in the half space over an infinitely large reflecting plane, without any other obstacles.
3.9 Frequency range of interest
The frequency range covered by the octave-band with a center frequency of 63 Hz~8000 Hz (1/3 octave-band of 50 Hz~10000 Hz).
3.10 Reference box
The smallest hypothetical rectangular hexahedron which envelops the sound source exactly and terminates on a reflecting plane (ground).
3.11 Measurement distance; d
The vertical distance between reference box and measurement surface of
hypothetical rectangular hexahedron.
3.12 Measurement surface
An external surface of a hypothetical rectangular hexahedron for measuring the sound pressure level with an area of S, which envelopes sound source and on which measurement point is located. The measurement surface ends at the reflecting plane (ground).
3.13 Background noise
All noises except the sound source being measured.
environmental conditions. Also, it shall take measures to ensure that any reflecting plane does not cause significant sound radiation due to vibration. 4.2 Background noise criteria
The time-averaged sound pressure level of background noise after averaging at microphone position shall be at least 3 dB lower than the uncorrected time- averaged sound pressure level of sound source being measured (unless
otherwise specified, hereafter known as sound pressure level for short), and preferably at least 10 dB lower.
4.3 Acoustic suitability criteria for test environment
Appendix A specifies the method of measuring the environmental correction K2. If K2A???7 dB, the acoustic suitability criteria for test environment in this Part are met; otherwise, the measurement is invalid.
5 Measuring instruments
5.1 General
Measurement systems including microphone, cable, and fan cover (if any) shall at least meet the requirements for Class 2 instruments specified in GB/T 3785.1. 5.2 Calibration
Before and after each series of measurements, each microphone shall, at one or more frequencies in the frequency range of interest, use sound calibrator to calibrate the entire measurement system. The sound calibrator shall at least meet the requirements for Class 1 instruments specified in GB/T 15173. The difference between unadjusted calibration readings of the measurement system before and after each series of measurements shall be less than or equal to 0.5 dB; otherwise, the series of measurements will be invalid.
Measurement systems and sound calibrators which meet the requirements and standard sound sources which meet the requirements of GB/T 4129, at regular intervals, shall be verified according to the corresponding standards.
Unless otherwise specified by national regulations, the interval between the verification of sound calibrators shall not exceed 1 year; and the interval between the verification of measurement systems and standard sound sources shall not exceed 2 years.
6.3 Working conditions
6.3.1 Working status
Noise radiation is related to the auxiliary devices installed in the engine. Whether air filter, exhaust silencer, and cooling fan, etc. are installed shall be recorded and described in the report. Gearbox or any driven machinery which loads the engine shall be explained in the report. The noise emitted by gearbox or the driven machinery shall be treated as additional noise.
Note. For the measurement of sound power level of exhaust noise of exhaust silencer, SEE ISO 15619.
For certain special-purpose (such as motorcycle) engines, if equipment or non- basic auxiliary devices (such as cooling with blower) are required to carry out bench test, the noise of the equipment or non-basic auxiliary devices shall be treated as additional noise. Or temporarily TURN off the equipment or non-basic auxiliary devices, but it shall ensure that the engine works properly.
Additional noise is part of background noise. Appropriate measures shall be taken to reduce its effect, to comply with the provisions of 4.2. For example, in the frequency range of additional noise, USE high-density material with a low transmission capability to shield or cover the structure surface; USE a silencer to reduce aerodynamic noise.
6.3.2 Operating conditions
When measuring noise, the engine shall operate stably at the ISO standard power and the corresponding rotational speed specified in GB/T 6072.1 under the reference conditions of ISO standard. At this time, the engine oil
temperature and cooling medium temperature are stable, and the ambient and intake air temperatures shall not be higher than 45 ??C.
If necessary, noise measurements can also be made in speeding up/down
working conditions or other working conditions and shall be explained in the report.
The measurement of engine power and corresponding rotational speed shall be conducted in accordance with the provisions of GB/T 6072.3.
7 Measurement
7.1 General
This section specifies a method - survey method (accuracy class 3) for the meteorological conditions, and explained in the report.
9 Recording content
The following content, if applicable, shall be collected and recorded to measure as required by this Part.
a) Engine.
1) Description of the engine, including model, specifications (e.g., type, number of strokes, number of cylinders, cylinder bore, stroke, boundary dimensions, cooling mode; ISO standard power and corresponding
rotational speed, etc.), number, manufacturer;
2) The type of fuel used and its octane or cetane number;
3) Diesel fuel injection timing (static and dynamic) or gasoline engine ignition timing (static and dynamic);
4) Base characteristics and the way in which the engine is connected to it (elastic or rigid);
5) The way in which the engine is connected to dynamometer equipment
(elastic or rigid);
6) Installation conditions, including the height of the crankshaft center of the engine and the bottom of oil pan from the reflecting plane;
7) Description of auxiliary devices, including air filter, exhaust silencer (if any), cooling fan (if any), and acoustic enclosure (if any);
8) Engine power and corresponding rotational speed during noise
measurements.
b) Acoustic environment.
1) Description of test environment (including physical descriptions of
ground, wall, and ceiling, and sketches of the locations of sound source being measured and other objects);
2) Description of acoustic environmental appraisal in accordance with the requirements of Appendix A;
3) Meteorological conditions (including atmospheric pressure,
temperature, relative humidity, and wind speed) near the sound source
during the noise test.
Appendix A
(Normative)
Methods for appraisal of acoustic environment
A.1 General
This appendix specifies the method for measuring environmental correction K2 and can be used to evaluate the effectiveness of a given measurement surface of the sound source being measured.
The first appraisal test (absolute comparison method, SEE A.2) is performed using a standard sound source. This method is suitable for indoor or outdoor use; and is a preferred method for appraisal of test environment, especially when the frequency band data is required, and the sound source being
measured can be removed from the test site.
The second appraisal test (according to room sound absorption method, SEE A.3) requires measuring the room sound absorption amount A. This test method is based on the following premises. The room shape is similar to a cube, is basically empty; and the room boundary has a sound absorption effect. The following four methods, reverberation time method, double-surface method, standard sound source method, and approximation method, can calculate the room sound absorption amount A. If the sound source being measured cannot be removed or has a large size, one of the methods may be preferred.
A.2 Absolute comparison method
The standard sound source whose characteristics meet the requirements of GB/T 4129 is placed on the ground of test environment. The center of the bottom surface coincides with the center of projection of bottom plane of reference box on the ground. The measurement surface, microphone position and its number are the same as those of the sound source being measured. According to the provisions of Chapter 7, MEASURE the sound power level of standard sound source, without environmental correction (ASSUME K2=0).
Environmental correction K2 shall be calculated according to the formula (A.1). Where.
LW* - Test environment sound power level of standard sound source, without

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