GB/T 20787-2023 in English

《GB/T 20787-2023往复式内燃机 结构噪声测量方法》由TC177（全国内燃机标准化技术委员会）归口，主管部门为中国机械工业联合会。

GB/T 20787-2023 Reciprocating internal combustion engines - Measurement method for structure-borne noise

1 Scope

This document describes the measurement methods for structure-borne noise emitted by reciprocating internal combustion engine.

This document is applicable to reciprocating internal combustion engines defined in GB/T 21404 (hereinafter referred to as "engines" unless otherwise specified).

2 Normative references

The following documents contain requirements which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.

GB/T 1859.1 Reciprocating internal combustion engines - Measurement of sound power level using sound pressure - Part 1: Engineering method
GB/T 1859.3 Reciprocating internal combustion engines - Measurement of sound power level using sound pressure - Part 3: Precision methods for hemi-anechoic rooms
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 13824 Mechanical vibration of rotating and reciprocating machinery - Requirements for instruments for measuring vibration severity
GB/T 14777 Geometrical orientation and directions of movements

3 Terms and definitions

For the purposes of this document, the terms and definitions given in GB/T 6072.1, GB/T 13824 and GB/T 14777 as well as the following apply.

3.1
structure-borne noise
vibration propagating in a solid structure in the range of audible audio frequencies
Note: The structure-borne noise in this document refers to the vibration propagating at the foot of the engine.

3.2
contact area
supporting area on the engine side where the engine is in contact with surrounding components, especially vibration isolators (e.g. rubber)

3.3
translational velocity level

Foreword i
Introduction iii
1 Scope
2 Normative references
3 Terms and definitions
4 Measurement environment
5 Measuring instruments
6 Installation and working conditions
7 Acceleration measurement
8 Calculation
9 Information to be recorded
10 Report
Annex A (Normative) Other connections between engine and test environment
Annex B (Normative) Height correction of sensor contact plane
Annex C (Normative) Determination of test frequency range
Annex D (Informative) Measurement records
Bibliography