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 2017 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:/standards.sae.org/J1342_201706 SURFACE VEHICLE RECOMMENDED PRACTICE J1342 JUN2017 Issued 1981-07 Revised 2017-06
5、Superseding J1342 JUN2012 Test Method for Determining Power Consumption of Engine Cooling Fan Drive Systems RATIONALE This document has been revised to show an additional method for determining power consumption of engine driven fan drive systems by looking at an alternative method for measuring in
6、vehicle fan power. 1. SCOPE The techniques outlined in this SAE Recommended Practice were developed as part of an overall program for determining and evaluating fuel consumption of heavy-duty trucks and buses, but it is applicable to off highway vehicles as well. It is recommended that the specific
7、operating conditions be carefully reviewed on the basis of actual installation data. Cooling requirements are affected by all heat exchangers that are cooled by the fan drive system. These may include radiators, condensers, charge air coolers, oil coolers, and others. Because of the variation in siz
8、e, shape, configuration, and mountings available in cooling fans and fan drive systems, specific test devices have not been included. Using known power/speed relationships for a given fan, this procedure can be used to calculate the fan drive systems power consumption for engine cooling systems usin
9、g fixed ratio, viscous or speed modulating, and mechanical on/off fan drives including electronically activated fan drives. This power consumption may then be used in determining engine net power per SAE J1349. For fan power/speed relationships, refer to SAE J1339. 1.1 Purpose The purpose of this do
10、cument is to provide a recommended method for determining and comparing the power consumption of fan drives over a variety of operating conditions. The resulting power consumption data is useful in predicting the fuel consumption of engines using these fan drives and in comparing one fan drive to an
11、other on the basis of power consumption. There is no known comparable ISO specification. SAE INTERNATIONAL J1342 JUN2017 Page 2 of 6 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the lat
12、est 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 and Canada) or +1 724-776-4970 (outside USA), www.sae.org. SAE J1339 Test Method for Measuring Performance of Engine Co
13、oling Fans SAE J1349 Engine Power Test Code - Spark Ignition and Compression Ignition - As Installed Net Power Rating 3. METHOD OF PRESENTING TEST DATA To evaluate the power requirement differential between the fixed ratio fan drive and a speed modulating or on/off drive the following formula will b
14、e utilized for all duty cycle conditions. Typical curves are shown in Figure 1. It should be noted that the curves shown in Figure 1, of the fan power and fan drive power, should be measured in the actual application. Since this is very difficult to do, an alternative method will be discussed in Sec
15、tion 5. If an approximation is all that is desired, the fan power can be measured, using a dynamometer during a laboratory airflow test, with the fan in the same shroud as the application and an engine silhouette positioned behind the fan at an appropriate distance. To evaluate the power, use the eq
16、uation: Total Power = (Ni No)(No2)(K) + (No3)(K) + Pl (Eq. 1) where: (Ni No)(No2)(K) = Slip/drag power (kW) (No3)(K) = Fan power (kW) Ni = Fan drive input speed (r/min) No = Fan drive output speed or fan speed (r/min) K = Fan constant Pl = Power loss associated with the fan drive system minus the fa
17、n and clutch but including belts, pulleys, and pulley bearings (kW) “K” fan constant is obtained by dividing fan power by the (fan speed)3 required to consume that power. SAE INTERNATIONAL J1342 JUN2017 Page 3 of 6 Figure 1 - Power versus fan speed Fan output speed (No) can be determined from curves
18、 such as those presented in Figures 2 and 3. Curves as shown in Figure 2 can be provided by the fan drive manufacturer. Curves as shown in Figure 3 would normally be derived by the fan drive user. Figure 2 - Fan speed versus fan-drive input speed F I G U R E 1 - P O W E R V E R S U S F A N S P E E D
19、M i n i m u m F a n S p e e d N o M a x i m u mMinimumPowerMaximumI n p u t S p e e d C o n s t a n tF a n P o w e rS l i p / D r a g P o w e rT o t a l F a n D r i v e I n p u t P o w e rM i n i m u m F a n D r i v e I n p u t S p e e d ( N i ) M a x i m u mMinimumFanSpeed(No)MaximumACBDEFG HF I G
20、U R E 2 - F A N S P E E D V E R S U S F A N - D R I V E I N P U T S P E E DO n - O f f D i s e n g a g e dV i s c o u s D i s e n g a g e dV i s c o u s E n g a g e dO n - O f f E n g a g e dPl SAE INTERNATIONAL J1342 JUN2017 Page 4 of 6 Figure 3 - Fan speed versus cooling air required 4. PROCEDURE
21、FOR ANALYZING VARIOUS TYPES OF FAN DRIVE SYSTEMS 4.1 The Section 3 method applied to the on/off drive is as follows: When operating conditions do not require fan drive actuation, fan speed (No) will fall on line G H (Figure 2), or may be zero (0) rpm (No = 0), depending on the particular fan clutch
22、being analyzed. When operating conditions require fan drive actuation, fan output speed (No) will fall along line A B of Figure 2. Given a specific input speed (Ni), the output speed (No) can be determined from line A B of Figure 3. 4.2 The Section 3 method applied to on/off and modulating viscous f
23、an drives is as follows: When operating conditions do not require fan drive actuation, fan speed (No) will fall on line E F of Figure 2. When operating conditions require fan drive actuation, fan speed (No) will fall on line C D of Figure 3. 4.3 The Section 3 method applied to speed modulating visco
24、us and hydraulic fan drives is as follows: When operating conditions do not require fan drive actuation the hydraulic fan drive output speed (No) will be at minimum and the viscous fan drive speed (No) will fall in the area EFHG of Figure 2. When operating conditions require fan drive actuation, fan
25、 speed (No) will fall within the boundaries of ABHG, Figure 2. Given the amount of cooling air required from the fan at a specific input speed (Ni), the output speed (No) can be determined from line E F of Figure 3. Note that the maximum fan speed will increase at lower air density. 5. ALTERNATIVE F
26、AN POWER CALCULATION METHOD 5.1 The alternative method requires a determination of the system restriction of the heat exchangers and engine cavity of the vehicle or fan application. 5.2 The vehicle must be positioned against a wind tunnel and sealed off such that the tunnel can blow air through it i
27、n a similar manner as if the fan were actually in use. The pressure and flow are measured and recorded for this test which yields a curve of system restriction. This curve can be plotted against a known flow curve of the fan at any rpm. The intersection of the two curves will yield the correct fan p
28、ower for the application. See Figure 4. 5.3 Once the intersection point is known, the power at all operating speeds can be determined using fan laws and the calculations shown in Step 3. Hydraulic Fan Drive SAE INTERNATIONAL J1342 JUN2017 Page 5 of 6 Figure 4 - System Restriction Method for Power Ca
29、lculation 3/21/2016 AIRFLOW - CFM/1000 0 0.8 1.6 2.4 3.2 4 4.8 5.6 6.4 7.2 8 8.8 9.6 10.4 11.2 12 12.8 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 0 4 8 12 16 20 24 28 32 36 40 Static Pressure - in H2O Efficiency 26283032343638Horsepower 15485 / 5.51 / 28.25 / 47.27% Fan Power Curve Fan
30、 Flow Curve System Restriction Curve System Operating Point Power at Operating Point Pressure Air Flow SAE INTERNATIONAL J1342 JUN2017 Page 6 of 6 6. SUMMARY After the total power requirement of any fan drive system has been determined, it can then be compared to the power requirement of the fixed r
31、atio fan drive system to determine the power difference at any operating point. Total power difference can be estimated by summing the various operating point differences in proportion to the respective time at each point in the duty cycle of the vehicle. 7. NOTES 7.1 Revision Indicator A change bar
32、 (l) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only. PREPARED BY THE SAE COOLING SYSTEMS STANDARDS COMMITTEE
