GB/T 20787-2023 English PDFUS$349.00 · In stock
Delivery: <= 4 days. True-PDF full-copy in English will be manually translated and delivered via email. GB/T 20787-2023: Reciprocating internal combustion engines - Measurement method for structure-borne noise Status: Valid GB/T 20787: Historical versions
Basic dataStandard ID: GB/T 20787-2023 (GB/T20787-2023)Description (Translated English): Reciprocating internal combustion engines - Measurement method for structure-borne noise Sector / Industry: National Standard (Recommended) Classification of Chinese Standard: J90 Classification of International Standard: 27.020 Word Count Estimation: 18,146 Date of Issue: 2023-09-07 Date of Implementation: 2024-04-01 Older Standard (superseded by this standard): GB/T 20787-2006 Issuing agency(ies): State Administration for Market Regulation, China National Standardization Administration GB/T 20787-2023: Reciprocating internal combustion engines - Measurement method for structure-borne noise---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order. ICS 27.020 CCSJ90 National Standards of People's Republic of China Replace GB/T 20787-2006 Measurement method of structure-borne noise of reciprocating internal combustion engines Published on 2023-09-07 2024-04-01 Implementation State Administration for Market Regulation Released by the National Standardization Administration Committee Table of contentsPrefaceⅠ Introduction II 1 Scope 1 2 Normative reference documents 1 3 Terms and Definitions 1 4 Measurement environment 3 5 Measuring instruments 3 6 Installation and working conditions3 7 Acceleration measurement 4 8 Calculate 8 9 Record content 9 10 Report 9 Appendix A (Normative) Other connections between engine and test environment 10 Appendix B (Normative) Sensor contact plane height correction 11 Appendix C (normative) Determination of test frequency range 12 Appendix D (informative) Measurement records 14 Reference 15ForewordThis document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1.Structure and Drafting Rules of Standardization Documents" Drafting. This document replaces GB/T 20787-2006 "Reciprocating Internal Combustion Engine Medium and High Speed Reciprocating Internal Combustion Engine Foot Structure Noise Test Regulations" Standard", compared with GB/T 20787-2006, in addition to structural adjustments and editorial changes, the main technical changes are as follows. a) Changed the “scope” (see Chapter 1, Chapter 1 of the.2006 edition); b) Changed “Terms and Definitions” (see Chapter 3, Chapter 3 of the.2006 edition); c) “Symbol” is deleted (see Chapter 4 of the.2006 edition); d) Added “measurement environment” requirements (see Chapter 4); e) Added provisions for "measuring instruments" (see Chapter 5); f) The provisions of "Installation and Working Conditions" have been changed (see Chapter 6, Chapter 6 of the.2006 edition); g) Changes to the provisions of "acceleration measurement" (see Chapter 7, Chapter 8 ~ Chapter 11 of the.2006 edition); h) Added provisions for “calculation” (see Chapter 8); i) Added provisions for “record content” (see Chapter 9); j) Added “reporting” requirements (see Chapter 10); k) Added “other connections between the engine and the test environment” (see Appendix A); l) Added "sensor contact plane height correction" (see Appendix B); m) The determination of the upper limit frequency in "Determination of Test Frequency Range" has been changed (see Appendix C, Chapter 7 of the.2006 edition). Please note that some content in this document may be subject to patents. The publisher of this document assumes no responsibility for identifying patents. This document is proposed by China Machinery Industry Federation. This document is under the jurisdiction of the National Internal Combustion Engine Standardization Technical Committee (SAC/TC177). This document was drafted by. Shanghai Internal Combustion Engine Research Institute Co., Ltd., Shanghai Automotive Group Co., Ltd. Commercial Vehicle Technology Center, Guangxi Yuchai Machinery Co., Ltd., Shanghai Institute of Electrical Engineering, Shanghai Motor Vehicle Inspection and Certification Technology Research Center Co., Ltd., Tongji University, Tianjin University Tianjin Internal Combustion Engine Research Institute (Tianjin Motorcycle Technology Center), Shanghai Automotive Group Co., Ltd., Pan Asia Automotive Technology Center Co., Ltd., Wei Diesel Power Co., Ltd., Hunan Liyu Gas Power Co., Ltd. The main drafters of this document. Zhang Hongbo, Song Xiangtai, Luo Miao, Yuan Weiping, Hu Aihua, Jiang Changlong, Yuan Ziyao, Li Songlin, Zhou Yi, Jia Bin, Jing Yabing, Liu Tao, Wang Xiaohu, Xu Chao, Lu Zhongdong, Wang Decheng, Song Endong, Yang Kai, Sun Ming, Ye Huaihan, Liu Ying, Qiao Liangliang, Wang Hongjian. This document was first published in.2006 and this is the first revision.IntroductionNoise from buildings, structures, ships, aircraft and land vehicles is often caused by the reciprocating internal combustion engines used and can be a major source of noise. Sound sources, even if they are not the main noise source, can produce background noise. These noises propagate in at least the following two ways. ---Directly entering the surrounding air, that is, air noise. GB/T 1859 specifies the measurement method for airborne noise radiated by internal combustion engines. ---Through excitation or vibration on supporting structures, pipes and shafts, that is, structure-borne noise. These vibrations form structural vibrations as they pass through the structure. Movement, which in turn excites the surface of the structure, producing so-called secondary sound waves or radiation of structural noise. The ability of the vibration source (engine) to generate vibration in the supporting structure depends on the amount of movement of the engine at its support, the engine support system and characteristics of load-bearing structures. The vibration of the engine foot may occur in the vertical direction, which is most easily noticeable, or in the longitudinal or transverse direction of the crankshaft; Vibration sources may also produce rotational inputs to the structure that are resolved along three orthogonal axes. Once any vibration is generated in a structure, it is difficult to control its propagation in the structure, especially in the low frequency region. Structural vibrations may occur at very Multiple vibration modes (such as compression, torsion or bending) propagate. Only by cutting off the continuity of the structure can the propagation of vibration be completely and effectively controlled. It is usually difficult to achieve. Structural damping may be effective for certain propagation modes, especially in the high frequency/shortwave region, but not specifically in the low frequency region. Don't be effective. Although it is difficult to control the propagation of vibration in a structure, it is still necessary to understand the vibration characteristics of the engine as a vibration source. It is helpful to select a competitive support, or to design the support according to the vibration characteristics of the selected engine. Measurement method of structure-borne noise of reciprocating internal combustion engines1 ScopeThis document describes methods for measuring structure-borne noise in reciprocating internal combustion engines. This document applies to reciprocating internal combustion engines defined in GB/T 21404 (hereinafter referred to as "engine" unless otherwise specified).2 Normative reference documentsThe contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, the dated quotations For undated referenced documents, only the version corresponding to that date applies to this document; for undated referenced documents, the latest version (including all amendments) applies to this document. GB/T 1859.1 Determination of sound power level of reciprocating internal combustion engines by sound pressure method - Part 1.Engineering method GB/T 1859.3 Determination of sound power level of reciprocating internal combustion engines by sound pressure method - Part 3.Semi-anechoic chamber precision method GB/T 6072.1 Reciprocating internal combustion engine performance Part 1.Calibration and test methods for power, fuel consumption and oil consumption Additional requirements for general purpose engines GB/T 6072.3 Reciprocating internal combustion engine performance Part 3.Test measurements GB/T 13824 Requirements for vibration intensity measuring instruments due to mechanical vibration of rotating and reciprocating machines GB/T 14777 Geometric orientation and direction of motion3 Terms and definitionsThe following terms and definitions as defined in GB/T 6072.1, GB/T 13824 and GB/T 14777 apply to this document. 3.1 structure-borne noise Vibrations that propagate in solid structures in the audible frequency range. Note. Structure-borne noise in this document refers to vibrations propagated at the engine feet. 3.2 contact areacontactarea The engine side support area where the engine is in contact with surrounding components, especially with vibration isolators (such as rubber). 3.3 Lv The base 10 logarithm of the ratio of the square of the velocity (v) to the square of the base velocity (v0) multiplied by 10. Note 1.The speed level can be calculated by formula (1). Lv=10lg v2 v20 (1) In the formula. v ---The velocity of the measured position along a certain axis, in meters per second (m/s); v0---base speed, is 5×10-8, the unit is meters per second (m/s). Note 2.The unit is decibel (dB). ......Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of GB/T 20787-2023_English be delivered?Answer: Upon your order, we will start to translate GB/T 20787-2023_English as soon as possible, and keep you informed of the progress. The lead time is typically 2 ~ 4 working days. 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Otherwise, follow the normal steps: Add to Cart -- Checkout -- Select your currency to pay.Question 5: Should I purchase the latest version GB/T 20787-2023?Answer: Yes. Unless special scenarios such as technical constraints or academic study, you should always prioritize to purchase the latest version GB/T 20787-2023 even if the enforcement date is in future. Complying with the latest version means that, by default, it also complies with all the earlier versions, technically. |
