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Disc and Drum Brake Dynamometer Squeal Noise Test Procedure
- Ground Vehicle Standard
- J2521_201304
- Revised
Downloadable datasets available
Annotation ability available
Sector:
Issuing Committee:
Language:
English
Scope
The SAE J2521 procedure is applicable to high frequency squeal noise occurrences for on-road passenger car and light trucks below 4,540 kg of GVWR. The procedure incorporates high temperature and low temperature test matrixes, but does not fully account for the effects of the environment on brake squeal. Much research is currently underway in this area and can potentially be incorporated in future revisions.
For the purposes of this test procedure, squeal is defined as peak noise levels equal to or above 70 dB(A) between 1.25 kHz and 16 kHz for tests using a full suspension corners or full axle assemblies, or between 2 kHz and 16 kHz for brakes not using a full suspension corner.
Before using this Recommended Practice for chassis dynamometer testing, review in detail the specifics related to at least (a) instrumentation including in-cabin microphones, (b) threshold levels for noise detection, (c) temperature control priority between front and rear axles, (d) vehicle loading and load distribution, (e) cooling air and environmental conditioning, and (f) detailed nomenclature and labeling of channels and sensors.
Rationale
The current revision of the SAE J2521 includes updates and changes to (a) accommodate for modern testing technologies, (b) improve the squeal noise evaluation matrixes for disc and drum brakes, (c) bring the document into the new SAE format standard, (d) revise its formatting for clearer test sequences, and (e) improve and harmonize definitions, noise evaluation, test setup and conditions, test inertia calculations, and data analysis with other SAE dynamometer test procedures and recent standards and developments from the EKB/VDA working groups in Europe. Lastly, this revision uses lower final temperatures during the fade sections to better represent vehicle-level testing while offering a more severe fade schedule as optional.
Recommended Content
Ground Vehicle Standard | Inertia-dynamometer Disc Brake Drag Measurement Test Procedure for Vehicles Less Than 4540 kg GVWR |
Ground Vehicle Standard | FMVSS Inertia Dynamometer Test Procedure for Vehicles Below 4540 kg GVWR |
Ground Vehicle Standard | Inertia Dynamometer Brake Squeal Noise Test Procedure for Vehicles without Regenerative Systems |
Topic
Data Sets - Support Documents
Title | Description | Download |
---|---|---|
Unnamed Dataset 1 | ||
Unnamed Dataset 2 | ||
TABLE 1 | FIXTURE LEVELS AND COMPONENTS REQUIRED | |
TABLE 2 | INITIAL BRAKE TEMPERATURES DURING FADE MODULES | |
TABLE 3 | NUMBER OF BRAKE APPLICATIONS FOR DISC BRAKES | |
TABLE 4 | TOTAL BRAKE APPLICATIONS PER TYPE OF SECTION WHEN USING COMBINATIONS OF SPEED, TEMPERATURE, AND PRESSURE LEVELS FOR DISC BRAKE MATRIX | |
TABLE 5 | DISC BRAKE SQUEAL MATRIX | |
TABLE 6 | NUMBER OF BRAKE APPLICATIONS FOR DRUM BRAKES | |
TABLE 7 | TOTAL BRAKE APPLICATIONS PER TYPE OF SECTION WHEN USING COMBINATIONS OF SPEED, TEMPERATURE, AND PRESSURE LEVELS FOR DRUM BRAKE MATRIX | |
TABLE 8 | DRUM BRAKE NOISE MATRIX | |
TABLE 9 | TABULAR SUMMARY OF NOISY STOPS PER TYPE OF SECTION AND FREQUENCY CLASS | |
TABLE A.1 | CUMMULATIVE NOISE OCCURRENCE AT GIVEN SPL AND RATING LINES AAA–F | |
TABLE A.1 | CUMMULATIVE NOISE OCCURRENCE AT GIVEN SPL AND RATING LINES AAA–F | |
Unnamed Dataset 14 |
Issuing Committee
The Brake NVH Standards Committee of the Foundaiton Brake Steering Committee develops and reviews information reports, recommended practices and standards related to brake NVH testing in the laboratory and in vehicles. Included are passenger car and light truck transportation.
Reference
Number | Title |
---|---|
IEC61672-1 | This document is not part of the subscrption. |
IEC61672-2 | This document is not part of the subscrption. |
IEC61672-3 | This document is not part of the subscrption. |
J2598_202012 | Automotive Disc Brake Pad Natural Frequency and Damping Test |
J2625_201707 | Automotive Vehicle Brake Squeal Test Recommend Practice |
J2786_201712 | Automotive Brake Noise and Vibration Standard Nomenclature |
J2789_201809 | Inertia Calculation for Single-Ended Inertia-Dynamometer Testing |
J2933_202209 | Verification of Brake Rotor and Drum Modal Frequencies |
J3001_201604 | Brake Insulator Damping Measurement Procedure |
VDA300 | This document is not part of the subscrption. |
VDA303 | This document is not part of the subscrption. |
VDA305 | This document is not part of the subscrption. |
VDA306 | This document is not part of the subscrption. |
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