1、_SAE Technical Standards Board Rules provide that: “This report is published 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 theref
2、rom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2008 SAE International All rights reserved. No part of this publication ma
3、y be 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: 724-776-4970 (outside USA)
4、Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgJ2744 AUG2008 SURFACEVEHICLERECOMMENDEDPRACTICEIssued 2008-08Requirements for Built-In Service Port for On Board Diagnostics RATIONALEThis document was originated by the USCAR/LEP Evaporative Emission Testing Group to
5、provide service access to automotive evaporative emission systems in a manner that would not damage those systems. To be effective it is essential that this service port be standardized. TABLE OF CONTENTS 1. SCOPE 21.1 Mission/Theme 21.2 Classification. 22. REFERENCES 22.1 Applicable Publication. 22
6、.1.1 SAE Publication 22.2 Related Publications . 23. DEFINITIONS . 34. DESCRIPTION 34.1 Applications. 34.1.1 Features 35. REQUIREMENTS . 35.1 Overall. 35.2 Evaporative System Flow Restriction . 35.3 Pressure Relief 35.4 Serviceability. 35.5 Labeling. 35.6 Mounting . 35.7 Location. 45.8 Ancillary Com
7、ponents Used to Incorporate the Service Port . 45.9 Durability . 45.10 Fuel Resistance 45.11 Sealing and Leaking . 45.12 Physical Attributes (Refer to Figures 1, 2 and 3) 45.13 Mechanical Requirements 5SAE J2744 Issued AUG2008 - 2 -1. SCOPE This document presents the requirements for a built-in serv
8、ice port to be used in vehicles intended to comply with Enhanced Evaporative Emissions Requirements. The primary function of the Service Port (Valve Assembly-EvaporativeEmission Canister Purge Harness Service) is to provide non-destructive access to the evaporative emissions system to enable testing
9、 of the integrity of the system. The Service Port is used to introduce air pressure or fuel vapors into, or evacuates them out of, the system. This access may be used for the following evaluations: Evaporative System Certifications Canister Loading and Purging End-of-line Testing System Integrity Se
10、rvice (e.g. OBD MIL on) Leak Location and Repair Verification In-Use Compliance Testing Canister Loading and Purging Inspection/Maintenance Testing System Integrity and Purge Check 1.1 Mission/Theme The Service Port is a component of the Evaporative Emissions Subsystem. It shall be an integral part
11、of the Enhanced Evaporative Emission Subsystem and therefore all requirements of that system must be met. 1.2 Classification The primary application of this service port will be passenger cars, and light, medium and heavy duty trucks that are required to have OBD II systems and meet Enhanced Evapora
12、tive Emissions Standards. This includes gasoline vehicles, and bi-fuel (gasoline/CNG) vehicles intended for sale in the United States and Canada or other marketplaces that adopt Enhanced Evaporative Emission Regulations similar to those in the United States and Canada. 2. REFERENCES 2.1 Applicable P
13、ublication The following publication forms a part of this specification to the extent specified herein. Unless otherwise specified, the latest issue of SAE publications shall apply. 2.1.1 SAE Publication Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-60
14、6-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.SAE J1681 Gasoline, Alcohol and Diesel Surrogates for Material Testing 2.2 Related Publications The following publications are provided for information purposes and are not a required part of this document. Federal Register fo
15、r OBD2: 40 CFR Part 86 Federal Register for Enhanced Evaporative Systems Federal Register for Inspection/Maintenance Programs Federal Register for ORVR California Documents OBD2 Final Rules: CARB Mail Out 93-40 SAE J2744 Issued AUG2008 - 3 -3. DEFINITIONS See SAE J1113/1 or SAE J551/1. 4. DESCRIPTIO
16、N The Service Port is a two-way, normally closed valve, which is integral to the evaporative emission system. The Service Port has a special universal fitting which mates to a regulated pressure source. The pressure source is capable of providing a limited amount of air pressure (or some other mediu
17、m, depending on specific usage of the Service Port, e.g. certification, service, etc.) into the system. The Service Port has design features to reduce the risk of inadvertently applying system pressure levels, which could violate the integrity of the evaporative system. The Maximum desired pressure
18、for testing the integrity of the evaporative system is 3.5 kPa (14.0 inches of water). 4.1 Applications The primary function of this service port will be passenger cars and light, medium and heavy duty trucks that are required to have OBD II systems and meet Enhanced Evaporative Emissions Standards.
19、 This includes gasoline vehicles and bi-fuel (gasoline/CNG) vehicles intended for sale in the United States and Canada or other marketplaces that adopt Enhanced Evaporative Emission Regulations similar to those in the United States and Canada. 4.1.1 Features The Service Port is designed to prevent a
20、 technician from directly applying unregulated air pressure when performing a test. 5. REQUIREMENTS 5.1 Overall The Service Port is an integral part of the enhanced evaporative emission system and therefore all requirements of that system must be met. In addition, the following requirements are adde
21、d: 5.2 Evaporative System Flow Restriction The addition of the Service Port to the system must not restrict purge flow. 5.3 Pressure Relief The Device is NOT expected to provide protection from pressure introduced into the system through any other source. 5.4 Serviceability The Service Port assembly
22、 shall be replaced if it becomes inoperable for any reason. No repair is possible. In the case of a design, that incorporates a serviceable valve core assembly, the assembly must meet the physical attributes and all other applicable requirements as stated in this document. 5.5 Labeling The cap/secon
23、dary seal or the tether shall be clearly labeled as described in the Physical Attributes section. 5.6 Mounting The Service Port shall be located within the engine compartment so that it is accessible and visible to service technician. The location should also provide protection for the Service Port
24、from damage due to usage, which is considered “normal” for the application in which it is utilized. SAE J2744 Issued AUG2008 - 4 -5.7 Location Under hood is the preferred and suggested location. (This will drive the specifications around temperature, materials, safety, etc.) In the event the under h
25、ood requirements can not be fulfilled, the location selected must be accessible without requiring any facilities or tools to gain access to the Service Port (i.e. vehicle hoists, dollies, hydraulic lifts, etc.). 5.8 Ancillary Components Used to Incorporate the Service PortAll materials utilized shal
26、l meet the minimum performance requirements imposed upon the evaporative emission system components for items including, but not limited to: permeation, durability, reliability, vibration, fuels exposure, temperatureand chemical exposure. 5.9 Durability The Service Port is an emission component and
27、is subject to the Useful Life provisions of the applicable regulations. For example, Enhanced Evaporative Emission regulations require such components to perform their intended function for a minimum of 10/11 year, 160 000/190 000 km (100 000/120 000 mile) durability. The Service Port must retain al
28、l performance requirements when accessed up to 3 times per year over the required useful life. 5.10 Fuel Resistance The Service Port assembly must be capable of withstanding exposure to various fuel vapors and/or liquid fuels per SAE J1681 to the extent of the performance requirements imposed upon a
29、ll of the evaporative emissions system components. 5.11 Sealing and Leaking 5.11.1 The Service Port must provide sealing (i.e. positive shutoff and a secondary seal/cap). 5.11.2 The Service Port must be capable of withstanding 860 kPa (125 psi) air pressure applied to either side of the valve. Under
30、 these conditions, the Service Port must maintain the sealing characteristics as described within these requirements (i.e. the valve must not open).5.11.3 At exposure to 6.221 kPa (25 inches of water) of air pressure, the leak rate for the Service Port (without the cap/secondary seal) shall not exce
31、ed 1 cc/min. 5.11.4 At exposure to 6.221 kPa (25 inches of water) of air pressure, the leak rate for the Service Port cap/secondary seal interface (the cap alone) shall not exceed 1 cc/min. with a maximum of 0.68 Nm (6 in-lbs) of torque on the cap/secondary seal. 5.12 Physical Attributes (Refer to F
32、igures 1, 2 and 3) 5.12.1 The top of the valve stem must be recessed inside of the valve stem housing to prevent inadvertent opening of the valve such as with a fingernail. The distance from the top of he Service Port (cap/secondary seal seat) to the top of the valve stem shall be a minimum of 3.94
33、mm (0.155 inches) to a maximum of 4.57 mm (0.190 inches) for the valve stem in the closed position. 5.12.2 100% flow through the Service Port shall be achieved by depressing the valve stem a distance no greater than 0.76 mm (0.030 inches) from the closed position. 5.12.3 The total valve stem travel
34、from the completely closed position to the fully open position shall be a minimum of 1.5 mm (0.060 inches). 5.12.4 The valve core assembly retaining thread shall have the following characteristics: 5.12.4.1 M6x0.75-6H THD “left hand” thread 5.12.4.2 Shall withstand 0.45 Nm (4 in-lbs) of tightening t
35、orque. SAE J2744 Issued AUG2008 - 5 -5.12.4.3 The valve core bridge (shoulder) shall withstand 3.4 Nm (30 in-lbs) of loosening torque. 5.12.5 The head of the valve core pin shall withstand a compression spring force consistent with what is needed to seal the valve at 860 kPa (125 psi). 5.12.6 The ca
36、p/secondary seal shall have the following characteristics: 5.12.6.1 A retaining thread of M12x1.5G THD with a “right hand” thread. 5.12.6.2 There shall be a minimum of 11 mm (0.430 inches) of length of thread available for engagement. 5.12.6.3 The threads shall withstand 1.6 Nm (14 in-lbs) of torque
37、. 5.12.7 As an option the cap/secondary seal may be “tethered” to the Service Port. 5.12.8 The cap color shall be green, specified with a P.M.S. # 349C, 357C, 355U, 356U, 363U, 364U or equivalent (Pantone Matching System, Pantone Professional Color System are trademarks of Pantone Inc., 55 Knickerbo
38、cker Rd., Moonachie, NJ 07074-9988, Tel: 201-935-5500. 5.12.9 The tether shall have the following wording, using white letters on black background: EVAP.SERVICE PORT. 1 PSI MAXIMUM. REGULATEDPRESSUREONLY.5.12.10 The words “HAND TIGHTEN ONLY” shall be printed on the cap. 5.12.11 Under no circumstance
39、s shall any silicone based lubricants be used on any component of the Service Port. 5.13 Mechanical Requirements 5.13.1 The service body shall withstand 4.5 Nm (40 in-lb) of torque. 5.13.2 The service port shall withstand a 89 N (20 lb) side load applied to the cap, in the plane of the assembly. 5.1
40、3.3 The service port shall withstand a 178 N (40 lb) normal (compressive) load on the cap. PREPARED BY THE SAE FUEL SYSTEMS TECHNICAL STANDARDS COMMITTEE SAE J2744 Issued AUG2008 - 6 -FIGURE 1 - SERVICE PORT CONFIGURATION SCHEMATIC DIAGRAM SAE J2744 Issued AUG2008 - 7 -FIGURE 2 - VALVE ASSEMBLY - BUILT-IN SERVICE PORT FOR ON BOARD DIAGNOSTICS SAE J2744 Issued AUG2008 - 8 -FIGURE 3 - VALVE STEM ASSEMBLY - BUILT-IN SERVICE PORT FOR ON BOARD DIAGNOSTICS
