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 there
2、from, is the sole responsibility of the user.” 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 2012 SAE International All rights reserved. No part of this p
3、ublication may 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: +1 724-776-497
4、0 (outside USA) Fax: 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/J335_201210SURFACE VEHICLE RECOMMENDED PRACTICE J335 OCT2012 Issued 1968-04 Revis
5、ed 2012-10 Superseding J335 JUN1995 Multiposition Small Engine Exhaust System Fire Ignition Suppression RATIONALE Revision of SAE J335 has become necessary in order to address new exhaust system technologies present on environmentally compliant small engines. 1. SCOPE This SAE Recommended Practice e
6、stablishes equipment and test procedures for determining the performance of spark arrester exhaust systems of multiposition small engines (19 kW) used in portable applications, including hand-held, hand-guided, and backpack mounted devices. It is not applicable to spark arresters used in vehicles or
7、 stationary equipment. 1.1 Purpose This document provides a method of evaluating the potential of multiposition small engine exhaust systems to ignite vegetative fuels. 1.2 Performance Recommended performance criteria are given in Appendix A. These requirements are adequate for the severe fire hazar
8、d condition posed by heavy vegetative fuels. However, during periods of extreme fire danger, exhaust systems meeting this document may not give absolute protection against fires. Additional operational restrictions may be necessary during such periods. 2. REFERENCES 2.1 Applicable Documents The foll
9、owing publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest issue of SAE publications shall apply. 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA
10、 and Canada) or 724-776-4970 (outside USA), www.sae.org. SAE J1349 Engine Power Test Code - Spark Ignition and Compression Ignition - As Installed Net Power Rating SAE J335 Revised OCT2012 Page 2 of 14 2.1.2 USDA Forest Service Publications Available from USDA Forest Service, Technology and Developm
11、ent Center, 444 East Bonita Avenue, San Dimas, CA 91773-3198. USDA Forest Service Standard 5100-1 Standard for Spark Arresters for Internal Combustion Engines D.S. Stocksted, “Spontaneous and Piloted Ignition of Pine Needles,” Research Note INT 194, USDA Forest Service, Northern Forest Fire Laborato
12、ry (1975) D.S. Stocksted, “Spontaneous and Piloted Ignition of Cheatgrass,” Prepublication Research Note, USDA Forest Service, Northern Forest Fire Laboratory (1976) R.T. Harrison, “Danger of Ignition of Ground Cover Fuels by Vehicle Exhaust Systems,” ED&T Report 5100-15, USDA Forest Service, San Di
13、mas Equipment Development Center (1970) 2.1.3 International Standards Organization (ISO) Publications ISO 7293 Forestry machinery - Portable chain saws - Engine performance and fuel consumption ISO 8178 Reciprocating internal combustion engines Exhaust emission measurement Part 1-8 2.1.4 United Nati
14、ons Economic Commission for Europe UN ECE-R120 “Uniform provisions concerning the approval of internal combustion engines to be installed in agricultural and forestry tractors and in non-road mobile machinery, with regard to the measurement of the net power, net torque and specific fuel consumption”
15、 3. DEFINITIONS 3.1 BEST POWER Power at maximum torque or rated speed achievable by a given test MSE at the maximum continuous corrected net brake power speed. (See SAE J1349 or equivalent standards, e.g. ISO 8178, ISO 7293 or UN ECE-R120). 3.2 CERTIFYING AGENCY The authority granting approval or di
16、sapproval of equipment tested per this standard per applicable laws or established performance standards. 3.3 CONTACT PLANE An imaginary flat surface defined by at least three points of contact on the surface of MSE power unit extremities. 3.4 EXHAUST GAS TEMPERATURE TEST A test to determine exhaust
17、 gas temperature at the points where the hottest gases impinge a contact plane. 3.5 EXPOSED SURFACES TEMPERATURE TEST A test to determine exhaust system temperatures at the points where the engine exhaust system comes in contact with or intersects the contact plane surfaces established by the extrem
18、ities of the MSE. 3.6 MAY A permissive condition. SAE J335 Revised OCT2012 Page 3 of 14 3.7 MULTIPOSITION SMALL ENGINE (MSE) A hand-held, hand-guided, or back-pack mounted unit having an internal combustion engine operable in more than one position. MSE configurations include, but are not limited to
19、, chain saws, weed trimmers, brush cutters, blowers, hedge trimmers, hand-held and backpack blowers, multi-task tools, and cut-off machines. 3.8 POWER UNIT A MSE product exclusive of extensions which are not integral to the operation of the engine, or which can be removed without tools. 3.9 SHALL In
20、dicate a mandatory requirement exclusive of all other methods. 3.10 SHOULD An advisory condition. 3.11 SPARK ARRESTER An exhaust system having the ability to control the amount and size of particulate debris emitted into the atmosphere by the exhaust flow (excluding cooling air of the engine). For t
21、he purposes of this document, the spark arrester consists of a heat and corrosion resistant metal screen with an opening size of 0.023 inches (0.58 mm) or less through which 100% of exhaust gases flow. 4. INSTRUMENTATION The following instrumentation is required: 4.1 Calibrated Loading Device An app
22、aratus designed to test MSEs at given loads and speeds which display torque or power and is compatible with a multipoint recorder or data logger. A calibrated loading device is required in chain saw temperature testing and is optional in temperature testing of MSEs other than chain saws. 4.2 Tachome
23、ter A device for determining the rotational speed (with a measurement accuracy 5% of tachometer reading) of a MSE. It may be separate or integrated with the calibrated loading device or multipoint recorder or data logging device. 4.3 Exhaust Gas and Surface Temperature Thermocouples Temperature ther
24、mocouple composed of Standard J or K type thermocouple wire with a grounded junction and a probe sheath diameter of 3.2 mm (1/8 in) or smaller. 4.4 Graduated Cylinders Calibrated containers for measuring amounts of fuel and lubricant for the fuel mix with an accuracy of 2% of the amount actually con
25、tained. 4.5 Wire Plug Gage A round wire gage of 0.610 mm (0.024 in) diameter with precision ground squared ends. Replace if any rounding is noted. SAE J335 Revised OCT2012 Page 4 of 14 5. SCREEN TEST The following screen test shall be made on all MSEs with removable (serviceable) screen-type spark a
26、rresters. Products using non-servicable (sealed) mufflers shall be subject to endurance testing per Appendix A. 5.1 Screen Housing Seal With the screen installed, probe the entire periphery for any gaps in the mounting structure. Any penetration using the wire plug test gage fails the test. When gag
27、ing, do not exceed 2 oz (0.56 N) of force. 5.2 Test With Screen Removed Remove the screen from the exhaust system and randomly probe the screen at least 20 times. Especially pay attention to any bends, molding, or edges. Any penetration using the wire plug gage fails the test. When gaging, do not ex
28、ceed 2 oz (0.56 N) of force. 5.3 Screen Housing Seal After Reassembly Install the screen in the exhaust system and repeat 5.1. 5.4 Screen Material Verify that the screen is constructed of a metal alloy which is heat and corrosion resistant. Verification may be performed through review of supplier ma
29、terial certifications or appropriate metallurgical analysis. 6. CONTACT PLANE DETERMINATION The contact planes are determined by the following method: 6.1 General 6.1.1 Determine the configuration of the MSE to be tested in accordance with 6.2 through 6.7. 6.1.2 Place the MSE power unit on a horizon
30、tal plane in the position which places the exhaust system nearest to that plane. In this position, identify three points where the power unit contacts the horizontal surface. This is the first contact plane. Using two existing contact points in the first plane, rotate the power unit until a third co
31、ntact point has been identified. This is the second contact plane. Repeat this process until a total of three contact planes have been established. Additional planes may be tested using good engineering practice. The contact plane closest to the exhaust flow direction shall be used for determination
32、 of the hot spot for the exhaust gas temperature. If any test plane contacts the exhaust system surface, the exhaust surface temperature shall be measured at this contact point. Mark the contact point accordingly. (Refer to Figure 1 for chain saws, Figure 2 for brush cutters, Figure 3 for hand held
33、blowers and Figure 4 for backpack blowers, Figure 5 for hedge trimmers, Figure 6 for Multi-Task tool, and Figure 7 for Cut-off machines) 6.1.3 Use narrow drafting-style tape and/or stiff, straight metal rods (3.0 mm or less in diameter) to connect the contact points in each plane, as shown in Figure
34、 1. These shall be used to provide more accurate thermocouple probe alignment during the test. SAE J335 Revised OCT2012 Page 5 of 14 6.2 Chain Saws 6.2.1 Assemble per manufacturers specification, without guide bar and chain, fuel, and oil. 6.2.1.1 If spikes or bumper bars are supplied and required b
35、y the manufacturer, test the saw with spikes in place. Locate the test planes from the root(s) of the uppermost bumper spike(s). 6.2.2 Fit a spacer, the same thickness as the bar, between the clutch cover and body and reinstall the clutch cover. The spacer shall not protrude beyond the body of the s
36、aw. 6.2.3 Secure the hand guard in the position specified by the minimum handle clearance of 35 mm (1.38 in) as required in ISO 7914. 6.2.4 Determine the planes per 6.1. 6.3 String Trimmers and Brush Cutters Use the power head and lower end shaft to determine the planes per 6.1. 6.4 Blower Test plan
37、es shall be identified per 6.1, excluding all blower tubes that can be removed without the use of tools. Where the exhaust port is vented within the blower duct, thermocouples should be attached to the outlet surface of the exhaust outlet duct. Thermocouples should be attached to the outlet surface
38、of the exhaust outlet. 6.5 Hedge Trimmers Contact planes for trimmers shall be determined per 6.1, with the cutting attachment installed. FIGURE 1 - CHAINSAW WITH CONTACT PLANES IDENTIFIED SAE J335 Revised OCT2012 Page 6 of 14 a)b)FIGURE 2 - (A) STRING TRIMMER IN DESIGN CONFIGURATION, (B) WITH CONTA
39、CT PLANES IDENTIFIED c)b)a)FIGURE 3 - (A) BLOWER IN DESIGN CONFIGURATION, (B) IN TEST CONFIGURATION (FIRST BLOWER TUBE REQUIRES TOOLS FOR REMOVAL), (C) TEST PLANES IDENTIFIED FIGURE 4 - BACK PACK BLOWER WITH TEST PLANES IDENTIFIED SAE J335 Revised OCT2012 Page 7 of 14 FIGURE 5 - (A) HEDGE TRIMMER IN
40、 DESIGN CONFIGURATION, (B) TEST PLANES IDENTIFIED FIGURE 6 - (A) MULTI-TASK TOOL IN DESIGN CONFIGURATION, (B) TEST PLANES IDENTIFIED SAE J335 Revised OCT2012 Page 8 of 14 FIGURE 6 - (A) CUT-OFF MACHINE IN DESIGN CONFIGURATION (LESS BLADE), (B), (C) TEST PLANES IDENTIFIED 6.6 Cut-Off Machines Remove
41、blade guard and blade (if design allows). If design allows re-install blade guard towards outside. Establish contact plane as the closest possible plane to the muffler and exhaust outlet. 6.7 Other MSE Configurations Determine planes for other configurations (that is, power drills, impact devices, a
42、nd compactors) without attachments or detachable accessories. 7. TEMPERATURE TEST Perform the following temperature tests on all MSEs: 7.1 Exposed Surface and Accumulation Area Temperature Test Measure exhaust system temperatures at the points where the engine exhaust system comes in contact with th
43、e plane surfaces established per 6.1. If the surface of the exhaust system contains pockets, recessions, or cavities which would preclude the removal of debris by gravity and/or normal operating motions of the device, the temperature in these accumulation areas must be measured. 7.1.1 Test Apparatus
44、 Use thermocouples welded or brazed to the exhaust system to determine temperatures. For chain saws, a calibrated loading device is required (Section 8). NOTE: During all tests, a thermocouple should be mounted to the cylinder head or spark plug gasket to monitor the head temperature. SAE J335 Revis
45、ed OCT2012 Page 9 of 14 7.2 Exhaust Gas Temperature Test Measure exhaust gas temperature at the points where the hottest gases impinge a plane established per 6.1. 7.2.1 Test Apparatus Use thermocouples to measure the exhaust gas temperature. For chain saws, a calibrated loading device is required.
46、For other MSE devices, excluding blowers, use of a calibrated loading device is optional. NOTE: During all tests, a thermocouple should be mounted to cylinder head or spark plug gasket to monitor head temperature. 7.3 Test Data The test data to be recorded for MSE temperature testing shall include t
47、he time, exhaust gas temperature, head and ambient temperatures, engine speed, torque and the exhaust surface temperature, if required. Recorded test data for MSEs other than chain saws may omit the torque data, if a calibrated loading device was not used. Recorded test data for MSEs other than chai
48、n saws shall include the method of loading, including the approximate percentage of the intake and/or discharge area blocked for blowers. 8. DETAILED TEMPERATURE TEST METHODS Use the following temperature test methods to test MSE exhaust systems. The ambient temperature during test runs shall be not
49、 less than 15 C (59 F). 8.1 Chain Saws 8.1.1 Preparation 8.1.1.1 Mount the test unit to the calibrated loading device as recommended by the manufacturer, without interference of the test plane. The width of the guide bar shall be simulated by an adapted guide bar or spacer of equivalent thickness. 8.1.1.2 Weld or braze surface temperature probes to all points found by the methods described in 6.1 and 6.2 where the test plane touches
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