GB/T 25982-2024 Limits and measurement methods for bus interior noise
1 Scope
This document specifies the limits, measurement instruments, measurement conditions, vehicle conditions, measurement methods, and test reports for the bus interior noise.
This document is applicable to vehicles of Categories M2 and M3.
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 of the referenced document (including any amendments) applies.
GB/T 3241-2010 Electroacoustics - Octave-band and fractional-octave-band filters
GB/T 3730.1 Terms and definitions of motor vehicles, trailers and combination vehicle - Part 1: Types
GB/T 3785.1-2023 Electroacoustics - Sound level meters - Part 1: Specifications
GB/T 3947 Acoustical terminology
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 15089 Classification of power-driven vehicles and trailers
GB/T 15173-2010 Electroacoustics - Sound calibrators
GB/T 19596 Terminology of electric vehicles
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 3730.1, GB/T 3947, GB/T 15089 and GB/T 19596 as well as the following apply.
3.1
steady noise
continuous noise that is generated when the vehicle operates in a stable working state, consisting of a mixture of tire noise, airflow noise, body vibration noise, powertrain, transmission system, or part and component operating noise
3.2
background noise
noise emitted by all noise sources other than the noise source being measured
Note: Background noise includes sound from airborne sources, noise from structural vibrations, and electrical noise within the instruments.
3.3
loudness
attribute of auditory perception that judges the intensity of sound
Note: Loudness primarily depends on the sound pressure that stimulates the auditory perception, but it is also related to the frequency and waveform of the sound, with the unit being sone.
[Source: GB/T 3947-1996, 9.7, modified]
3.4
sharpness
auditory sensation that describes the degree to which the timbre of a sound is sharp or harsh
Note: Sharpness is a psychological metric that measures the amount of high-frequency components in a sound, reflecting the ratio of high-frequency energy to the total energy in the sound, with the unit being acum. 1 acum is the sharpness produced by a 60 dB narrowband noise with a center frequency of 1 kHz and a bandwidth of 160 Hz.
3.5
stage of charge; SOC
percentage of the capacity that can be released from the current battery according to the specified discharge conditions in the available capacity
[Source: GB/T 19596-2017, 3.3.3.2.5]
4 Noise limits
4.1 The sound pressure level and loudness of the interior noise in internal combustion engine buses and hybrid buses shall not exceed the limits specified in Table 1.
5 Measurement instruments
6 Measurement conditions
7 Vehicle conditions
8 Measurement method
9 Test report
Contents
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Noise limits
5 Measurement instruments
6 Measurement conditions
7 Vehicle conditions
8 Measurement method
9 Test report
Annex A (Informative) Measurement points and microphone positions
Annex B (Informative) Measurement record of bus interior noise
Annex C (Informative) Calculation method for loudness and sharpness evaluation indexes
Bibliography
