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VW_82469_Englisch

Accessory Devices

Acoustic Requirements

Previous issues

VW 82469: 2005-10, 2006-03

Changes

The following changes have been made as compared to VW 82469: 2006-03:

–Evaluation of brief noises expanded

Scope

This Standard defines the acoustic requirements and testing conditions that must be fulfilled by the accessory device to be developed, e.g., window lift, control motor, relay, pump, valve.

For the time being, the specifications apply to accessory devices that are used in motor vehicles with a conventional combustion engine. For motor vehicles with an electric drive or hybrid vehicles with the combustion engine switched off and the electric drive running, all specifications and limit curves specified below for conventional vehicles with the combustion engine switched off apply.Acoustic evaluation of the accessory device in the laboratory Measuring room The evaluation parameter for the airborne noise is the A-weighted sound level measured according to DIN EN 61672-1, Class 1, or the one-third octave spectrum determined under the same conditions.The measurement must be performed in a free field above a reflective plane. Apart from the reflective plane, all walls of the measuring room must be fitted with sound-absorbing material, such that this does not influence the sound field in the frequency range that is of interest. An example of this is shown in DIN 45635-1 (1984-04, Section 3.5).

1 2 2.1 Group Standard VW 82469

Issue 2010-03

Class. No.:

8BG00Descriptors:accessory devices, acoustics, noise

Check standard for current issue prior to usage.

This electronically generated standard is authentic and valid without signature.

The English translation is believed to be accurate. In case of discrepancies the German version shall govern.Numerical notation acc. to ISO practice.Page 1 of 15

Technical responsibility

Standards Department EGNA/3Dr. Friedrich Bielert Tel.: +49 5361 9 31580EKDV/4 Wolfgang Tiefenbach EKDV Tel.: +49 5361 9 75357Manfred Terlinden Confidential. All rights reserved. No part of this document may be transmitted or reproduced without prior permission of a Standards Department of the Volkswagen Group.Parties to a contract can only obtain this standard via the B2B supplier platform https://www.wendangku.net/doc/3915602707.html,.

? Volkswagen Aktiengesellschaft VWNORM-2008-12m

The quiescent noise level in the measuring room must be evaluated using a one-third octave spectrum in the frequency range 20 Hz to 16 000 Hz. The individual one-third octave bands of the quiescent noise level must be at least 10 dB below the corresponding one-third octave levels of the accessory device to be measured.

Measuring setup

The measuring setup is based on DIN 45635-1. In accordance with this standard, measurements are performed at different points on a spherical surface at a distance of 1 m from the center of the noise source. The radius vector from the center of the noise source to the spherical surface is the normal of the face surface of the microphone.

The number of microphones must first be chosen to be ≥ 9, in accordance with accuracy class 2. The number must be increased as long as the difference in dB between the highest and the lowest mea‐sured total level is numerically greater than the previous number of microphones (in accordance with DIN 45635-1, Section 5.4.4.2). The orientation of the device under test (DUT) with respect to the microphones must be selected in such a way that the maximum sound level is recorded and functional capability of the equipment is assured.

If the radiated sound field changes by a sufficiently small amount during the entire period of operation,measurements may be made using fewer than 9 microphones, provided this has been approved by the purchaser.

Operation of the accessory device

Operation of the accessory device for three complete operation cycles (run-in procedure). From the fourth cycle onwards, measuring of every complete operation action (e.g., open, close) of the acces‐sory device five times.

Load conditions for the accessory device

Corresponding to the load conditions that occur during vehicle operation.

Measurements under deviating load conditions must be approved by the purchaser.

Operating voltage of the accessory device

Operation of the accessory device at a voltage of 13,5 V, measured at the electrical connectors on the accessory device, except where other operating voltages have been specified.

Settings for the measuring systems

The sound pressure must be recorded over time and represented as A-weighted decibels. The inte‐gration constant (time over which each individual signal level is averaged during the measurement period) must be 125 ms. When a sound level meter is used, this value corresponds to the "fast"setting. The dynamic range must be adjusted to an optimized signal/noise ratio.

One-third octave spectrum of the accessory device The maximum A-weighted total sound level that occurs at a spherical surface must be determined according to Section 2.2. If fluctuations occur in the amount of sound emitted over the running time of the accessory device, then the maximum value that occurs temporally and spatially must always be used as the evaluation criterion. The position of the maximum total sound level determined in this manner is used to determine the one-third octave spectrum.

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The one-third octave bands must be determined using the arithmetic average method over the whole running time that is relevant to each application, with use of one-third octave filters in accordance with DIN EN 61260.

If significant fluctuations in the one-third octave levels occur during the running time (deviations greater than 3 dB, as compared to the average one-third octave level over the running time), then

these must be documented separately.The process described must be carried out for at least 3 identical devices. Serial numbers and the point of maximum noise emission must be documented.

Figure 1 – One-third octave limit curves for airborne sound from accessory devices during a laboratory

measurement

Legend

Occupant-operated accessory device with combustion engine running 2

Occupant-operated accessory device with combustion engine switched off and accessory device starting automatically with combustion engine running 3

Accessory device starting automatically with combustion engine switched off Total sound pressure level

The following total sound pressure level values must not be exceeded:

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–

65 dB(A)Occupant-operated accessory device with combustion engine running –

60 dB(A)Occupant-operated accessory device with combustion engine switched off and accessory device starting automatically with combustion engine running –55 dB(A)Accessory device starting automatically with combustion engine switched off

Modulation level

To ensure a high-quality sound impression, the noise emitted by the accessory device must vary only to a limited extent. For adjusting drives, for example, periodic variations of the rotational speed must be avoided (running out of true, "wobbling").

Frequency variations over time can be evaluated by plotting the frequency spectrum over time (spec‐trogram) or by plotting the multiples of the rotational speed (orders) over time.

The relative frequency change Δf/f of the operating noise must not exceed a value of 1% in one second.

Amplitude variations over time can be evaluated, for example, by plotting the sound level over time.The integration constant of the sound level must be selected to be sufficiently small, and must be agreed upon with the purchaser.The relative level change ΔL/L must not exceed a value of 0,5 dB. Changes over time during starting operation or stopping operation (see Figure 2) are excluded from these requirements.

Figure 2 shows the starting operation and stopping operation of an accessory device. The course of the operating frequency or the course of the sound level is schematically plotted in any unit as a function of time t.

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Figure 2 – Starting and stopping operation of an accessory device

Legend

Duration of the starting operation 2

Duration of the stopping operation 3

Mean value 4

Instantaneous value Tonality

Within a one-third octave spectrum, an individual one-third octave band must not deviate from both neighboring one-third octave bands by more than 3 dB. A deviation of more than 3 dB from only one of the two neighboring one-third octave bands is permissible.

Evaluation of the noise of briefly operating accessory devices

Briefly operating accessory devices are accessory devices for which the sound pressure exceeds 25% of the maximum value for the first time and/or falls below 25% of the maximum value for the last time within a time period T 1 of at most 1 s (Figure 3).

The sound pressure used for this criterion must be measured with a minimum sampling rate of 22 kHz.The evaluation described here applies to noises occurring once (e.g., relay clicking) and successions of brief noises (see Figure 4) at a time interval T 2 greater than 0,05 s. For shorter times T 2, the noise is considered to be continuous.

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Figure 3 – Pressure curve over time of a brief noise Figure 4 – Pressure curve over time of a succession of brief noises Section 2.1 through Section 2.5 also apply. The maximum A-weighted sound pressure level occurring in the observed time period applies as the evaluation criterion (time constant "fast", see for example DIN EN 61672-1). The A-weighted sound pressure level of the brief noise according to Figure 3 is given in Figure 5 as an example. The maximum sound pressure level used for the evaluation is marked by an arrow.

A one-third octave band evaluation is not performed.

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Figure 5 – A-weighted sound pressure level of the signal from Figure 3The limits specified in Section 2.8 apply to the maximum level. However, the measured A-weighted sound pressure level receives a pulse increase of 6 dB for the brief noises or successions of brief noises defined above.

Subjective evaluation

The noise characteristic of the accessory device must not exhibit any unpleasant noise components,across the entire operating range.

The development goal is to ensure that neither the interior nor exterior noise of the accessory device can be perceived as being disturbing. This evaluation represents a prerequisite for release approval.Where necessary, psychoacoustic measurement techniques must be used for objective substantia‐tion.

Structure-borne sound from accessory devices Measuring room

The accessory devices must be evaluated in a low-vibration room.

Measuring setup

All connection points that are provided for attaching the accessory device to the vehicle must be fitted with triaxial force sensors. The accessory device must be attached via the force measurement sen‐sors to a rigid support structure (e.g., a solid mounting plate), orientated as it would be when installed (in the vehicle).

Operating conditions of the accessory device According to Section 2.3.

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Load conditions of the accessory device According to Section 2.4.

Operating voltage of the accessory device According to Section 2.5.

Determination of one-third octave spectra for forces

The dynamic forces in the three spatial directions (X, Y, Z) must be recorded for all connection points on the accessory device. These must be interpreted in the form of averaged one-third octave bands,making use of one-third octave filters as described in DIN EN 61260 according to the arithmetic average method.

It must be ensured that a sufficiently high sampling rate is used.

If significant fluctuations in the one-third octave level occur during the running time (deviations greater than 3 dB, as compared to the average one-third octave level over the running time), then these must be documented separately.

The one-third octave spectra for all forces measured at the connection points must be added ac‐cording to the formula:

(1)

(addition of the rated values).

The one-third octave spectrum that results from this equation must be represented as a step diagram below the limit curve, using one-third octave center frequencies in the frequency range 16 Hz to 1000 Hz. The level axis must show a spreading of 40 dB.

Limit curves for the one-third octave spectra for forces

The sum of internal forces that are transmitted at all connection points to the subframe must not exceed the one-third octave limit curve shown below (Figure 6).

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Figure 6 – Limit curves for the one-third octave spectra for forces

Legend

Occupant-operated accessory device with combustion engine running 2

Occupant-operated accessory device with combustion engine switched off and accessory device starting automatically with combustion engine running 3Accessory device starting automatically with combustion engine switched off

Figure 6 shows the limit curves for the total of the forces applied to the connection points by the accessory device in newtons (N) as a function of frequency (Hz).

Acoustic evaluation of accessory devices installed in the vehicle Measuring room

Except for the reflective plane, all walls of the measuring room must be fitted with sound-absorbing material, such that they do not influence the sound field in the frequency range of interest. An example of this is shown in DIN 45635-1, Issue 1984, Section 3.5.

The quiescent noise level in the vehicle must be evaluated using a one-third octave spectrum in the frequency range 20 Hz to 16 000 Hz. The individual one-third octave bands of the quiescent noise level must be at least 10 dB below the corresponding one-third octave levels of the accessory device to be measured.

All other sources of acoustic interference in the vehicle must be switched off during the measurement.The measurement takes place with the combustion engine switched off.

Operation of the accessory device

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Load conditions for the accessory device

Corresponding to the maximum load conditions that occur during vehicle operation.

Measurements under deviating load conditions must be approved by the purchaser.

Operating voltage of the accessory device

Operation of the accessory device at a voltage of 13,5 V, measured at the electrical connectors on the accessory device, except where other operating voltages have been specified. If necessary, the vehicle battery must be buffered using an external power supply that can provide sufficient power.The voltage of the power supply must correspond to the voltage of the charge controller with the combustion engine running, i.e., usually ≥ 14,1 V.

Interior noise Measuring setup for evaluation of interior noise

The interior noise must be measured at the positions of the driver's ears and at the positions of the ears of a passenger on the right rear seat. The measurement can be performed with individual mi‐crophones, headband microphones, or an artificial head.

Settings for the measuring systems According to Section 2.6.

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One-third octave spectrum of the accessory device

A step diagram with the respective one-third octave limit curve is used to represent the A-weighted one-third octave spectrum against the one-third octave center frequencies, in the frequency range 20 Hz to 16 000 Hz (see Figure 7 and Figure 8). The one-third octave bands must be determined using the arithmetic average method over the whole running time that is relevant to each application,with use of one-third octave filters in accordance with DIN EN 61260.

be documented separately.

The process described must be carried out for at least 3 devices. The serial numbers must be doc‐umented.

Figure 7 – One-third octave limit curves for airborne sound from occupant-operated accessory de‐

vices

Legend

With combustion engine running 2With combustion engine switched off

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Figure 8 – One-third octave limit curves for airborne sound from accessory devices starting auto‐

matically

Legend

Start with combustion engine running 2

Start with combustion engine switched off Total sound pressure level

The following total sound pressure level values must not be exceeded:

–

45 dB(A)Occupant-operated accessory device with combustion engine running –

40 dB(A)Occupant-operated accessory device with combustion engine switched off –

40 dB(A)Accessory device starting automatically with combustion engine running –35 dB(A)Accessory device starting automatically with combustion engine switched off

Modulation level According to Section 2.9.

Tonality According to Section 2.10.

Evaluation of the noise of briefly operating accessory devices According to Section 2.11.

Subjective evaluation According to Section 2.12.

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Exterior noise Measuring room The vehicle must be placed in a measuring room according to Section 2.1. A distance between the vehicle body and the walls of at least 2 m must be observed.

Measuring setup for evaluation of exterior noise

Record the exterior noise using a microphone. This microphone must be positioned at the same height as the accessory device, at a distance of 1 m from the vehicle body. The normal of the diaphragm surface of the microphone must be at right angles to the vehicle body.

Operation of the accessory device According to Section 2.3.

Load conditions for the accessory device According to Section 2.4.

Operating voltage of the accessory device According to Section 2.5.

Setting of the measuring system Set integration constant and dynamic range according to Section 2.6.

One-third octave spectra of the accessory device

A step diagram with the limit curve is used to represent the A-weighted one-third octave spectrum against the one-third octave center frequencies, in the frequency range 20 Hz to 16 000 Hz (see Figure 9). The one-third octave bands must be determined using the arithmetic average method over the whole running time that is relevant to each application, with use of one-third octave filters in accordance with DIN EN 61260.

The process described must be carried out for at least 3 devices. The serial numbers must be doc‐umented.

4.6

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Figure 9 – One-third octave limit curves for exterior noise from accessory devices

Legend

With combustion engine running 2

With combustion engine switched off Total sound pressure level

The following total sound pressure level values must not be exceeded:

–

40 dB(A)With combustion engine running –35 dB(A)With combustion engine switched off

Modulation level According to Section 2.9.

Tonality According to Section 2.10.

Evaluation of the noise of briefly operating accessory devices According to Section 2.11.

Subjective evaluation According to Section 2.12.

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Referenced documents

The following documents cited in this standard are necessary for application.

In this Section terminological inconsistencies may occur as the original titles are used.

Standards with the titles given in German are either only available in German or may be procured in other languages from the institution issuing the standard.

DIN 45635-1

Measurement of noise emitted by machines; airborne noise emission; en‐veloping surface method; basic method, divided into 3 grades of accuracy DIN EN 61260

Electroacoustics - Octave-band and fractional-octave-band filters DIN EN 61672-1Electroacoustics - Sound level meters - Part 1: Specifications 5 Page 15

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