1、 SURFACE VEHICLE RECOMMENDED PRACTICE J549 MAR2015 Issued 1947-12 Revised 2015-03 Superseding J549 MAR2013 (R) Preignition Rating of Spark Plugs RATIONALE Information updated to reflect current industry practice related to the heat range testing of spark plugs. Key changes are noted below: Deleted r
2、eferences to obsolete U.S Government publications related to lubricating oil and oil for fuel and added applicable SAE document references. Updated section on operating conditions to include engine warm-up procedure. 1. SCOPE This SAE Recommended Practice describes the equipment and procedures used
3、in obtaining preignition ratings of spark plugs. 1.1 The spark plug preignition ratings obtained with the equipment and procedure specified herein are useful for comparative purposes and are not to be considered as absolute values since different numerical values may be obtained in different laborat
4、ories. 2. REFERENCES 2.1 Applicable Documents The following 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 Publication Available from SAE International, 400 Commonwealth Drive, War
5、rendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. SAE HS840 Manual for the SAE 17.6 Cubic Inch Spark Plug Rating Engine, including Maintenance and Overhaul SAE J1899 Lubricating Oil, Aircraft Piston Engine (Ashless Dispersant) SAE J1966 Lub
6、ricating Oil, Aircraft Piston Engine (Non-dispersant Mineral Oil) SAE J2203 SAE 17.6 Cubic Inch Spark Plug Rating Engine _ 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
7、 voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, 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. S
8、AE invites your written comments and suggestions. Copyright 2015 SAE International All rights reserved. No part of this publication 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
9、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) 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 visi
10、t http:/www.sae.org/technical/standards/J549_201503 SAE INTERNATIONAL J549 Revised MAR2015 Page 2 of 6 3. EQUIPMENT SAE 17.6 engine with the cylinder barrel either knurled or honed, with or without chemically treated surface, and compression piston rings which may or may not be chrome plated. 4. SPE
11、ED The nominal speed is to be 2700 rpm, but is not to be over 2765 rpm when firing, nor below 2670 rpm when motoring. 5. COMPRESSION RATIO 5.6:1. 6. IGNITION SOURCE Magneto or approved alternate. 7. SPARK PLUG INSTALLATION Threads in the spark plug hole opening should conform in size and length to t
12、he standards established by SAE for the rating engine. 7.1 SAE recommended torque values should be used when installing plugs in the engine/bushing. 7.1.1 Reducer bushings or adaptors should not be used. 8. FUEL Although 98% - one degree Benzene, 2% - Specification SAE J1966 SAE 60 NONADDITIVE aviat
13、ion oil, with 0.8 mL/L (3 cc/gal) T.E.L. added has been used as the standard for many years, availability of benzene is becoming highly restricted by virtue of it being a known carcinogen. In lieu of this fact, a number of substitute or alternate fuels are being tested as replacements. Such fuels ar
14、e Toluene or a suitable leaded racing gasoline, which has sufficient octane rating to insure proper operation without a propensity towards spark knock or detonation. It still must be noted that additives such as aviation oil and T.E.L. must be used in those fuels to underwrite cylinder wear and valv
15、e seat longevity. Even with those safeguards in place, the amount of boost required to preignite a plug may be limited by the octane rating of those alternate fuels, which are obtainable. 9. FUEL INJECTION TIMING The fuel injector or injector pump port shall begin to close 60 degrees 5 degrees of cr
16、ankshaft angle After Top Dead Center (ATDC) on the intake stroke. 10. FUEL CIRCULATION RATE 2 L/min 1 L/min (1/2 gal/min 1/4 gal/min). 11. FUEL INJECTION PUMP Using a mechanical fuel injection system, gallery pressure of the fuel injection pump is to be 100 kPa 10 kPa (15 psi 2 psi). However, feed s
17、ystem pressures to an approved alternate electronic fuel injection system could vary widely with type being used. The main requirement is to insure that an adequate pressure is maintained for proper operation. 12. FUEL PRESSURES-INJECTION With a mechanical system, pressure should be 5170 kPa (750 ps
18、i) minimum. When using an approved alternate electronic fuel injection system, the minimum pressure required should be adequate to guarantee sufficient fuel delivery and atomization for engine operation. SAE INTERNATIONAL J549 Revised MAR2015 Page 3 of 6 13. MIXTURE STRENGTH (FUEL TO AIR RATIO) The
19、mixture strength is that which gives maximum thermal plug temperature. 14. COOLANT The coolant should be water plus .26 g/1 L (1 g/gal) of an inhibitor. The total dissolved and suspended solids should not exceed 120 ppm. 15. JACKET INLET TEMPERATURE a. With pressure cooling control - 107 C 3 C (225
20、F 5 F) b. With insert head engine - 88 C 1 C (190 F 2 F) 16. COOLANT FLOW 20 L/min 2 L/min (5 gal/min 1/2 gal/min). 17. CRANKCASE OIL If main and/or rod bearings are silver or suspected of being silver alloy, oil is to be nonadditive SAE J1966, SAE viscosity grade 60 aviation oil. If it is determine
21、d that bearings are not of a silver composition, then either the nonadditive SAE 60 viscosity aviation oil or an additive oil, which complies with SAE J1899 may be used. Included in this are multiviscosity lubricants approved for replacing the SAE viscosity grade 60 aviation oil. 18. OIL PRESSURE a.
22、 In main bearings, 650 kPa 40 kPa (95 psi 5 psi) b. In valve gear, 100 kPa (15 psi) minimum at operating temperature 19. OIL TEMPERATURE 88 C 5 C (190 F 10 F). 20. OIL QUANTITY Oil level is maintained at the center of the oil level sight glass if so equipped without the engine rotating. If a needle
23、valve assembly is used in place of a sight glass, oil must be released when opened. 21. OPERATING CONDITIONS These operating instructions are for use with the 17.6 Spark Plug Rating Engine. It is recognized that individual laboratories will have slightly different operation requirements; however, th
24、e fundamental operations should follow these instructions as closely as possible so that the rating results will be comparable. Only those conditions that affect the rating of the spark plug or the safety of personnel and equipment are specified as required, but recommended procedures or conditions
25、are indicated for information and guidance purposes. SAE INTERNATIONAL J549 Revised MAR2015 Page 4 of 6 21.1 Required Operating Conditions Speed: 2700 + 65/ - 30 rpm Ignition Timing: 30 degree btc (automotive types), 40 degree btc (aviation or others not rateable at 30 degrees) Fuel Injection Pressu
26、re: 5.17 Mpa (750 psi) minimum. Fuel-Air Ratio: That which produces the maximum thermal plug temperature. Air Inlet Temperature: 107.2 C 2.8 C (225 F 5 F). Air Inlet Humidity: 75 + grains of water per pound of dry air. Bushing Outlet Coolant Temperature: 87.8 C 1.0 C (190 F 2 F). Engine Oil Temperat
27、ure: 87.8 C 5 C (190 F 10 F). 21.2 Step-by-Step Engine Warm-up Procedure 21.2.1 Select the proper spark plug insert (see SAE J2203 Appendix B). 21.2.2 After being sure that the cylinder head insert seat, as well as the spark plug insert itself, is clean, install the insert carefully into the cylinde
28、r head, using new O-rings. The O-rings should be assembled onto the insert and may be held in place with a small amount of petroleum jelly or light grease. 21.2.3 The hold-down nuts are to be alternately tightened so that the insert will seat evenly in the cylinder head. The nuts are to be tightened
29、 finally to a uniform 6.78 N-m (60 lb-in) torque. 21.2.4 Install a warmup spark plug similar to the type to be rated, using the specified installation torque (SAE J2203 Appendix C). A new gasket is recommended for each installation, except conical seating types. 21.2.5 Before starting the engine, be
30、 certain that it has the proper type and amount of lubricating oil in the crankcase, oil in the fuel injection pump base, cylinder jacket and spark plug insert cooling system filled, air pressure supply system filled to the proper water level, and the fuel supply tank filled with fuel. Be certain th
31、at the cylinder air pressure supply throttle valves are tightly closed and that the atmospheric air throttle valve is fully open. Turn on the electrical power to all units and set the switch on “high” for the base oil heaters. Turn on the water to the fuel cooler, the crankcase aspirator if used, an
32、d all temperature control valves. Turn on the control air supply. 21.2.6 Because there are many installations that use dynamometers other than the frequency changer synchronous type now furnished as part of the standard assembly in the United States, only typical directions will be given here for th
33、e starting of the dynamometer. However, most installations include certain safety interlocks that must be bypassed during the initial starting of the engine. This is normally accomplished by holding the “start” button depressed until the oil pressure increases to above the safety setting. As long as
34、 the fuel injection pump control is in the closed position, no fuel will be delivered to the injection valve and the engine will not fire. Under no conditions should a cold engine be motored or run at speeds above 900 rpm. 21.2.7 After any required motoring is completed, the engine can be fired by g
35、radually increasing the displacement of the fuel injection control by means of the micrometer screw until firing takes place. The displacement should continue until the thermal plug temperature reaches a maximum. By this time, the dynamometer will have changed from motoring to absorbing. The dynamom
36、eter can now be unlocked for power and friction readings. No ratings are to be attempted until the oil temperature has been stabilized at 88 C (190 F). Much warmup time may be saved by leaving the crankcase oil heaters turned on - even overnight. CAUTION: Always be certain that the dynamometer shell
37、 is locked and that the atmospheric inlet air throttle valve is fully open and the cylinder air pressure throttle valves are completely closed before the engine is started or stopped. SAE INTERNATIONAL J549 Revised MAR2015 Page 5 of 6 21.2.8 When the engine is ready for testing, it is stopped by dis
38、engaging the fuel injection pump control from the micrometer screw and then disconnecting the electrical power from the dynamometer. As soon as the engine comes to a complete stop, disconnect the ignition cable from the warmup spark plug and remove it. Install the spark plug to be rated and connect
39、the ignition cable. Bring the engine up to speed with the dynamometer and connect the fuel injection pump control to the micrometer screw. The engine will start firing immediately. Unlock the dynamometer shell. With the speed maintained at 2700 rpm, slowly open the main cylinder air pressure throttl
40、e valve while slowly closing the atmospheric air throttle valve, constantly watching the intake boost gauge. During the transfer of air supplies, the intake boost should remain at about atmospheric pressure. 21.2.9 After the transfer to pressurized air is complete, the engine can be operated with in
41、creasing boost pressure in regular steps until preignition of the spark plug takes place. This is evidenced by a rapid rise in the thermal plug temperature. CAUTION As soon as preignition occurs, the fuel should be cut off by disconnecting the linkage between the fuel injector pump control and the m
42、icrometer screw. Failure to act promptly can cause damage to the engine and especially to the spark plug on test. As soon as the fuel is cut off, the thermal plug temperature will decrease. 21.3 Preignition Point The plug rating is that IMEP value obtained on the engine at a point where the supercha
43、rge pressure is 3.37 kPa (1 in Hg) below the preignition point. The following steps are recommended to attain the preignition point. 21.3.1 The supercharge pressure is increased in 13.5 kPa (4 in Hg) increments until preignition occurs as indicated by a rapid rise in thermal plug temperature or as i
44、ndicated by an approved ionization detection system. At each setting, the mixture strength is adjusted such that a maximum thermal plug temperature is obtained and held for 3 minutes. 21.3.2 When preignition occurs, the fuel supply and ignition are instantly cut off and the supercharge pressure is d
45、ecreased 6.7 kPa (2 in Hg) and the plug allowed a cool down time of 10 s, at which point the fuel and ignition are turned back on. Fuel is once again adjusted for maximum thermal plug temperature until stable engine operation for 3 minutes is obtained or preignition occurs. 21.3.3 If preignition occ
46、urs after Step 21.3.2 the supercharge pressure should be reduced by 3.37 kPa (1 in Hg) again adjusting for peak thermal temperature until stable engine operation for 3 min is obtained or preignition occurs. If preignition occurs, refer to Step 21.3.5. 21.3.4 If, after Step 21.3.2 stable engine opera
47、tion is obtained, the supercharge pressure should be increased by 3.37 kPa (1 in Hg), again adjusting for highest thermal plug temperature until stable engine operation for 3 min is obtained or preignition occurs. If preignition occurs, refer to Step 21.3.5. 21.3.5 Friction torque should be measured
48、 at supercharge pressure 3.37 kPa (1 in Hg) below the preignition point (or previous stabilized setting prior to preignition), and within 30 s after the engine ceases to fire. 21.3.6 Rating data may be verified using a plug that has a rating point at least 50 IMEP above the plugs that have been rated. SAE INTERNATIONAL J549 Revised MAR2015 Page 6 of 6 22. CALCULATION OF IMEP Indicated HP = Friction HP + Brake HPIHP = (2700 / 5252) x TF)+ ( 2700/5252) x TB)(Eq. 1) IHP = 0.51 (TF + TB) = Plan/33,000 0.51(TF + TB) (0.04) (0.01) P = IMEP IMEP = 8.65 (TF + TB) TF - Friction Torque TB - Bra
