1、_ 6$(7HFKQLFDO6WDQGDUGV%RDUG5XOHVSURYLGHWKDW7KLVUHSRUWLVpublished by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the
2、 sole responVLELOLWRIWKHXVHU SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2014 SAE International All rights reserved. No part of this publication may be
3、reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970 (outside USA) Fa
4、x: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J2973_201402 SURFACE VEHICLE RECOMMENDED PRACTICE J2973 FEB2014 Issued 2014-02 Fuel Components and
5、Systems Leak Tightness Specifications and Test Practices (or Methods) RATIONALE Fuel components and systems must have no Hydrocarbon (HC) leakage, to support compliance with certain HC emission regulatory requirements. This practice recommends use of a standard geometry leak channel (Equivalent Chan
6、nel) to set the leak threshold for fuel components and systems. The method enables usage of multiple leak test technologies and test conditions, as long as they comply with the specified test practices and requirements. TABLE OF CONTENTS 1. SCOPE 2 1.1 Purpose . 2 2. REFERENCES 2 2.1 Applicable Docu
7、ments 2 2.2 Related Publications . 3 3. DEFINITIONS . 3 4. SYMBOLS . 4 5. MEASUREMENT UNITS DEFINITIONS . 4 6. TERMINOLOGY 5 7. BACKGROUND 6 8. LEAK TIGHTNESS REQUIREMENTS . 6 9. LEAK TEST METHODS AND TECHNOLOGIES . 7 9.1 Leak Test Process Set Up and Method Validation Requirements 8 9.2 Measurement
8、System Capability 9 9.3 Leak Test Requirements (PV and IP tests). 10 10. NOTES 10 10.1 Marginal Indicia . 10 SAE INTERNATIONAL J2973 Issued FEB2014 Page 2 of 15 APPENDIX A FLOW CURVES OF COMMON EQUIVALENT CHANNELS . 11 APPENDIX B GUIDELINE FOR TEST METHODS/EQUIPMENT THAT USES THE EC FOR CALIBRATION
9、13 APPENDIX C LEAK TEST RECOMMENDED PRACTICE . 14 TABLE A MAXIMUM ALLOWED EC FOR FUEL COMPONENTS AND ASSEMBLIES: . 7 1. SCOPE This SAE recommended practice specifies a standard geometry leak channel to set the leak threshold and compare results from a variety of leak test technologies and test condi
10、tions. This practice applies to fuel system assemblies and components which have a risk of allowing regulated fuel or fuel vapors to continuously escape to atmosphere. A component or assembly tested to this standard has a zero HC leakage threshold because the selected leak channel (Equivalent Channe
11、l) will self-plug and will not emit measurable hydrocarbon liquid or vapors. Therefore this standard eliminates leaks as a source of evaporative emission. This practice was primarily developed for pressurized and non-pressurized fuel systems and components containing liquid hydrocarbon based fuels.
12、1.1 Purpose 1.1.1 Provide generic leak tightness specifications based on an Equivalent Channel (or maximum allowed micro-channel type of defect). 1.1.2 Define specific Equivalent Channel sizes for fuel line assemblies, vapor management components and fuel tank assemblies that will result in no hydro
13、carbon SHED detectable emission due to leaks 1.1.3 6SHFLI/HDN7HVW0HWKRGV5HTXLUHPHQWVDQG3UDFWLFHVWRVHWXSDQGTXDOLIDOHDNWHVWPHWKRGVDQGFRPSDUHdissimilar test conditions. NOTE: It should be noted that fuel components and systems normally exposed to fuel fluids (liquid and vapor) are tested to meet HC emi
14、ssion requirements with test methods utilizing compressible, non-hazardous gases such as air, nitrogen, and helium. 2. REFERENCES 2.1 Applicable Documents The following publications are for reference only. Unless otherwise indicated, the latest issue of SAE publications shall apply. 2.1.1 SAE Public
15、ations Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. SAE J2587 Appendix C- Fuel System Components Leak Test Specifications issued 2005 SAE J2045 Appendix A- Fuel System Compon
16、ents Leak Test Specifications issued 2012 2.1.2 ASTM and ISO Publications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org Available from International Organization for Standardization, ISO Central Secretariat,
17、 1, ch. de la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, Tel: +41 22 749 01 11, www.iso.org. ASTM E1316-07 Standard Terminology for Nondestructive Examinations-Section E ISO/IEC 17025-2005 General requirements for the competence of testing and calibration laboratories SAE INTERNATIONAL J297
18、3 Issued FEB2014 Page 3 of 15 2.2 Related Publications The following publications are provided for information purposes only. M.J. Harrigan )XHO 6VWHP and measurement non-linearity. B.3 A master part (as defined in 9.1.5) must be used to set up the test system. The master part must be independently
19、qualified to have less than 10% of EC leak flow rate at steady state condition when connected to the test fixture. The calibration will be performed at the actual test condition (pressure, gas type and mixture). B.4 The master part and set up (timing for pressurizing, evacuation, stability, etc.) Mu
20、st be recorded and locked. Any change in timing parameters or test volume will require recalibration and system qualification. B.5 7KHPDVWHUSDUWZLOOEHXVHGWRVHWXSWKHRIDFFHSWDQFHUDQJHSRLQWRIWKHWHVWVHWXSZLWKDOOWHVWVHWXS(including time parameters) as used during normal production. B.6 The master part wi
21、th the EC connected to it, using the same set up and pressure as during normal production, will be used to set up the 100% of acceptance range (measurement units are dependent on the specific instrument). B.6.1 EC and master part must share the same gas supply, especially in the cases of tracer gase
22、s (helium or helium mixtures). B.6.2 When using tracer gases, the EC must be fully vented to air (inlet and outlet) before applying the test sequence. Helium has higher viscosity compared to air and nitrogen, so air will leak out first, causing lower helium concentration. B.7 The master part raw rea
23、dings must be recorded when performing frequent calibration, and increasing master part UHDGLQJV QRPRUHWKDQ PXVWWULJJHUFRUUHFWLYHDFWLRQWRUHSDLUWKHVRXUFHRIOHDNDJHUDWKHUWKDQDXWR-HURWKHtest system. B.8 The frequency of this calibration process varies and is dependent on instrument, measurement technolo
24、gies and environmental constrains; and should be established based on the robustness of the measurement system. The calibration frequency will be established by the user. Some pressure decay systems and helium mass spectrometry systems are calibrated as frequently as once per shift. For frequent cal
25、ibration, it is recommended that the process will be automated with minimal operator involvement. SAE INTERNATIONAL J2973 Issued FEB2014 Page 14 of 15 APPENDIX C - LEAK TEST RECOMMENDED PRACTICE It should be emphasized that the leak test Methods per this standard are only a tool to ensure that the U
26、UT does not leak at the time of test. Leak testing cannot predict the long term performance of a component. Part condition and presentation for leak testing as well as fixture design and test set-up parameters are critical to ensure a reliable leak test process. The following sections are to be used
27、 as guidelines and reference only. C.1 PART HANDLING AND PRESENTING FOR LEAK TEST 1. The part must be dry and clean. Excessive lubricants on joints can mask leaks by plugging the leak path during testing. Lubrication is typically gasoline soluble and can open up once exposed to gasoline. 2. If shop
28、air is used as the test media, the air must be free from oil and water. 3. The part must be allowed enough curing/stability time so it can be presented to the leak test system in a stable condition. UUT test temperature should be similar to the condition shipped to the customer. 4. Virtual leaks mus
29、t be allowed to fully vent so the part is presented at barometric conditions. 5. When retesting a UUT shortly after the first test, provide enough time between tests to allow the UUT (and its virtual OHDNV WRIXOOUHWXUQWREDURPHWULFFRQGLWLRQVDQGEHSUHVHQWHGDVDIUHVKSDUW6RPHSDUWPDWHULDOGHVLJQVHKLELWVKRUW
30、WHUPPHPRUDIWHUHSRVXUHWRSUHVVXUH,WLVFRPPRQWKDWDVHFRQGDLUOHDNWHVWZLOOUHVXOWLQDORZHUOHDNlevel if there is not enough time between tests. This can result in passing a marginal part if rejection limits are established using untested components. When performing a repeat test, the user must verify during i
31、nitial set up that the master part with EC attached is still rejected and master part by itself is accepted. 6. Rejected parts must be clearly segregated and means shall be in place to ensure that rejected parts are disposed of and not shipped to the final customer. C.2 FIXTURING, EQUIPMENT AND PROD
32、UCT SEAL DURING LEAK TEST 1. The Fixture must ensure that the UUT will not get damaged and be properly supported during leak testing. 2. Components should be tested, when applicable, in the same orientation that they will be installed. 3. The leak test equipment must comply with local safety and env
33、ironmental standards. Operators and the environment must be protected for high gas pressure when catastrophic failures occur. 4. The UUT must be sealed on the same sealing surfaces as it is during assembly in the vehicle. 5. When possible use mating connectors with minimal tolerance to reduce UUT se
34、al compression, which enhances the ability to detect defects at the sealing area. (e.g., SAE J2044 requirements) 6. The fixture design must ensure minimum virtual leaks, which can bias the leak test results. 7. Helium test fixtures (especially hard vacuum applications) must be constructed from stain
35、less steel, or similar material to minimize out-gassing. Hard vacuum practices must be used. 8. Connections and tubing cannot be standard automation pneumatic connections, but rather connections applicable to low level leak test and high vacuum systems. SAE INTERNATIONAL J2973 Issued FEB2014 Page 15
36、 of 15 C.3 LEAK TEST SET UP Test Pressure: 1. Increasing test pressure and UUT expansion under pressure should be optimized for the highest throughput and shortest test time. 2. Higher pressure increases EC flow rate (Appendix A), which can improve test system capability and improve production throu
37、ghput. 3. As the UUT and joints can be deformed under high pressure, care must be taken to ensure that by pressurizing the UUT operating pressure leaks are not masked. 4. Set up shall follow the guidelines in section 9.1. Test Process and test time: 1. Leak test time (throughput) should be designed
38、for the most efficient throughput without compromising the ability to detect unique leaks possible for a given part design. 2. When using helium as a tracer gas, it should be recognized that helium has a higher viscosity than air. Therefore, at higher pressures (viscous flow conditions) EC and longe
39、r defects must be properly evacuated from air before helium flow will be fully developed. If process Failure Mode Effect Analysis indicates the probability of such long micro-channel defects longer than the EC per section 8 (table A), proper set up time must be included to ensure the leak test syste
40、mV ability to detect this failure mode. 3. When using tracer gas (e.g., Helium), care must be taken to allow for tracer gas concentration not to build up in the test area after test and/or due to leakage. Tracer gas (e.g., Helium) must be removed from the test area and tracer gas concentration in the test stand must be monitored.
