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 entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefro
2、m, 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.TO PLACE A DOCUMENT ORDER; (724) 776-4970 FAX: (724) 776-0790SAE WEB ADDRESS http:/www.s
3、ae.orgCopyright 2000 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.SURFACEVEHICLE400 Commonwealth Drive, Warrendale, PA 15096-0001RECOMMENDEDPRACTICESubmitted for recognition as an American National StandardJ1489REV.MAY2000Issued 1987-06Revised 2000-05Superseding J1489 J
4、UN1987(R) Heavy Truck and Bus Retarder Downhill Performance Mapping Procedure1. ScopeThe procedure covers the estimation of the total retardation capability available to a specific vehiclefrom:a. Natural retardation (rolling resistance, aerodynamic drag, etc).b. Engine dragc. Engine, integral automa
5、tic transmission, driveline or trailer-axle retardersIt assumes that foundation brakes are not used for maintaining speed on long mountain descents.Retardation is rated in terms of the maximum grades on which stable control speeds can be maintained foreach gear over the range of highway speeds appro
6、priate to that gear. For each gear, the calculationprocedure determines maximum grades for at least four values of control speed ranging from the vehiclevelocity corresponding to full load governed engine rpm, to the vehicle velocity corresponding to the enginerpm at minimum (idle) speed. In additio
7、n, the calculation procedure provides information on the total retardingpower available for each gear.1.1 PurposeThis procedure provides a uniform method for calculating and reporting the steady-state controlspeed maintainable by either engine, integral automatic transmission, driveline, or trailer-
8、axle retardersemployed by heavy trucks and buses operating on downgrades. It provides a practical method of predictingretarder performance in a specified vehicle installation using data describing retarder performancecharacteristics and other vehicle design variables. It is intended to assist in the
9、 proper selection of a retarderby matching stated retarder performance capabilities with particular vehicle functional requirements.2. References2.1 Applicable PublicationsThe following publication forms a part of the specification to the extent specifiedherein. Unless otherwise indicated, the lates
10、t revision of SAE publications shall apply.2.1.1 SAE PUBLICATIONAvailable from SAE, 400 Commonwealth Drive, Warrendale, Pa 15096-0001.SAE J1252SAE Wind Tunnel Test Procedure for Trucks and BusesCOPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1489 Revised
11、MAY2000-2-3. Definitions3.1 Weight FactorsW total vehicle weights kg (lb)3.2 Vehicle DimensionsA Vehicle frontal area m2 (ft2) (see Table 1 for listing of typical values.) (Product of vehiclesmaximum height and width.)RM Number of power unit tire revolutions per kilometer (mile) (see Table 2 for a l
12、isting of typicalvalues.)Number of trailer tire revolutions per kilometer (mile).TABLE 1TYPICAL VALUES FOR VEHICLE FRONTAL AREAS (A) (REF. SAE J1252)Vehicle Type Frontal AreaVans (Both conventional and cab-over engine power units) 10.0 m2 (108 ft2)Tankers see Table 6 for a listing of typical values.
13、)385/65R 22.5 305 8.2520 542425/65R 22.5 291 9.0020 520445/65R 22.5 285 9.0022.5 542275/80R 24.5 311 10.0020 504285/75R 24.5 309 10.0022 482305/75R 24.5 304 10.0022.5 52011.0020 49211.0022 47011.0024 45711.0022.5 50411.0024.5 48212.0020 48212.0024 44312.0022.5 49212.0024.5 47013.0020 45714.7517.5 58
14、114.0020 43914.0024 40315.0019.5 52115.0022.5 48116.519.5 50416.522.5 46718.0019.5 49118.0022.5 45619.5019.5 467TABLE 3TYPICAL VALUES FOR VEHICLE AERODYNAMIC WINDAVERAGED DRAG COEFFICIENTS (Cd)Trucks Coaches/Buses0.80 for a vehicle not equipped with aerodynamic aids on its roof. 0.45 for an intercit
15、y coach or suburban bus0.64 for a vehicle equipped with aerodynamic aids. 0.55 for a motor home or school busTABLE 2SOME TYPICAL VALUES FOR TIRE REVOLUTIONSPER KILOMETER, RK(REVOLUTIONS PER MILE RM) BY TIRE SIZE (CONTINUED)Size Rev/kilometer Size Rev/MileCOPYRIGHT Society of Automotive Engineers, In
16、c.Licensed by Information Handling ServicesSAE J1489 Revised MAY2000-4-3.4 Subscriptsi Subscript used to denote each gear with i=1 corresponding to the highest numerical transmissiongear ratio (that is, the lowest gear).j Subscript used to denote the combined ratio of drive axle(s) and auxiliary tra
17、nsmissions, if present,with j=1 corresponding to the highest numerical combined ratio (that is, the lowest axle/transmission range).TABLE 4TYPICAL VALUES FOR HIGHWAY SURFACE COEFFICIENTSON CLEAN DRY PAVEMENT (CR)Road Type CRSmooth concrete 0.000Worn Concrete, Brick, Cold Blacktop 0.002Hot Blacktop 0
18、.005TABLE 5TYPICAL VALUES FOR ROLLING RESISTANCE COEFFICIENT (CT)Tire Type CT (km/h) CT (mph)Bias Ply (6.6 + 0.029 V) x 103 (6.6 + 0.046 V) x 103Radial Ply (4.1 + 0.026 V) x 103 (4.1 + 0.041 V) x 103TABLE 6TYPICAL VALUES FOR ALTITUDECORRECTION COEFFICIENTS (CAL)Altitude - m (ft) CAL 0 (0) 1.0500 (16
19、39) 0.961000 (3279) 0.921500 (4918) 0.882000 (6557) 0.842500 (8197) 0.803000 (9836) 0.76 3500 (11 475) 0.724000 (13 115) 0.684500 (14 754) 0.645000 (16 393) 0.60COPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1489 Revised MAY2000-5-3.5 SpeedsEngine speed
20、in revolutions per minute (rpm) with transmission in gear i and the rear axle/auxiliarytransmission in ratio j.Full load governed engine speed (rpm)Engine idle speed (rpm)V Vehicle velocity in kilometers per hour - km/h (miles per hour - mph)Vehicle velocity, km/h (mph) corresponding to the full loa
21、d governed engine speed (Negov) with thetransmission in gear i and the rear axle/auxiliary transmission in ratio j.Vehicle velocity, km/h (mph) corresponding to the engine idle speed (Nemin) with the transmissionin gear i and the rear axle/auxiliary transmission in ratio j.Driveline speed (rpm)NTR T
22、railer-axle retarder speed (rpm)VC Control speed (equilibrium speed on a downgrade), km/h (mph)3.6 Gear RatiosTransmission gear ratio for the ith gearCombined drive axle and, if appropriate, auxiliary transmission gear ratioRTR Trailer axle ratio (gear ratio determining the rotational speed of a ret
23、arder installed on a trailer axle)3.7 Efficiencies(See Table 7 for a listing of typical values.)ED Power-unit drive axle efficiencyETR Trailer axle efficiencyEO Overall drive system efficiency3.8 PowerPN Natural retardation power, kW (hp)PE Engine retarding power, kW (hp) (see Figures 1 and 2)PRE Re
24、tarder power from an engine-speed retarder, kW (hp)PRD Retarder power from a driveline-speed retarder, kW (hp)PTR Retarder power from a trailer axle retarder, kW (hp)PS Total retarding power available, kW (hp)PG Grade power demand, kW (hp)TABLE 7TYPICAL VALUES FOR DRIVETRAIN EFFICIENCIES (ED, EO, ET
25、R) EFFICIENCY COEFFICIENTVehicleConfigurationsED EOTransmissionManualEOTransmissionAutomaticETR4x2 Tractor 0.94 0.92 0.90 6x4 Trailer 0.90 0.88 0.86Retarder equipped trailer axle 0.95NeijNegovNeminVgovijVminijNDjRtiRajCOPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling Se
26、rvicesSAE J1489 Revised MAY2000-6-TYPICAL VALUES FOR ENGINE FRICTION POWER (Figures 6 and 7)(Does not include radiator fans,alternators, power steering pumps, etc.)In lieu of specific engine friction data, the attached typical graphs may be used for obtaining friction levels as afunction of displace
27、ment for typical 2- and 4-cycle diesel engines.FIGURE 1ESTIMATES OF 4 CYCLE DIESEL ENGINE FRICTION POWERCOPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1489 Revised MAY2000-7-FIGURE 2ESTIMATES OF 2 CYCLE DIESEL ENGINE FRICTION POWER3.9 Retardation Numeric
28、sG Grade of the hill (tangent of the angle of the hill).GM Maximum grade allowable for a given set of values for PS, W, and VC.COPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1489 Revised MAY2000-8-4. Description of ApproachThe calculation procedure provi
29、des the user with the ability to map an individualretarders performance in a specific vehicle equipped to the users specifications for a specific mission orfunction. Multiple performance maps can be developed and compared until the user is satisfied that a suitablematch is achieved for the operation
30、 intended for the vehicle.Since the calculation procedure is vehicle specific, a significant amount of detailed information about variouscharacteristics of the vehicle is required. An additional amount of more generic information is also required. Atthe option of the user, these data may be either s
31、upplied by the user or extracted from the accompanyingtables and figures of typical values. Figure 3 is a suggested worksheet for listing and entering data forsubsequent use in the calculation procedure. The first section of input data (entitled, Vehicle Description)serves to document the type of ve
32、hicle for which the calculation procedure is being applied, as well as definingvalues for key variables in the equations. The value for vehicle weight is the weight at which the vehicle willroutinely be operated and for which retarder performance is to be matched.The second section of input data (en
33、titled, Powertrain Specifications) contains both descriptive and numericdata about the vehicles powertrain. Gear ratios are those of the transmission and drive axle(s) in use in thevehicle. For vehicles equipped with retarders integral to trailer axles, the gear ratio and efficiency of thiscomponent
34、 must be determined.The third section of input data (entitled, Operating Conditions) contains descriptive and numeric data relative tothe roadway and operating conditions in which the vehicle will routinely be operated. Typical values for threeof the variables of interest are available in Tables 4,
35、5, and 6, however, user supplied data may also be usedfor these variables, if desired.The fourth section of input data (entitled, Vehicle Power Input Parameters) contains user supplied data relativeto the particular vehicles engine friction and retarder(s) power outputs at four designated vehicle an
36、d enginespeed conditions. Methods for determining values for these variables are described in 5.1.1, 5.1.2, 5.1.3, and5.1.4.5. Calculation Procedures5.1 Total Retardation AvailableThe total amount of retarding power capable of being generated by the vehicleis the sum of all the individual retarding
37、powers as shown in Equation 1:(Eq. 1)Equation 1 applies to vehicles equipped with either a mechanical transmission or an automatic converter typetransmission when it is in the lockup mode of operation. When retarders are used with automatic convertertype transmissions in the non-lockup mode, it is n
38、ecessary to compensate for the feedback (slip)characteristics of the converter. Under these conditions, if specific feedback (slip) characteristics for thetransmission in question are not available, the PS calculation should be modified as follows in Table 8:TABLE 8APPROXIMATE TORQUE CONVERTER SLIP
39、LOSS FACTORRetarding Device InstalledIntegral with ConverterTransmissionConversion Factor for OperationIn the Non-Lockup ModeNone (PE/E0) x 0.80Transmission Input Retarder (PE/E0 + PRE/E0) x 0.80Transmission Output or Driveline Retarder 0.80 (PE/E0) + PRD/EDPS PEEO- PREEO- PRDED- PTRETR- PN+=COPYRIG
40、HT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1489 Revised MAY2000-9-FIGURE 3TRUCK RETARDER PERFORMANCE MAPPINGCOPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J1489 Revised MAY2000-10-5.1.1 BASIC ENGINE RETARDING POW
41、ERValues for basic engine friction or rotating power are inserted at four ormore engine speeds (Ne) which include the full load governed engine speed and engine idle speed and atleast two intermediate values. (User supplied values for these variables are preferred, but absent availabledata, typical
42、values chosen from Figures 1 or 2 may be used.) For the purposes of this calculation, thesevalues shall not include parasitic losses associated with engine accessories such as air compressors,radiator fans, power steering pumps, or other auxiliary power devices.5.1.2 ENGINE SPEED RETARDER POWERValue
43、s for the engine speed retarders power shall be listed, permanufacturer supplied data, at the same engine and vehicle speeds which were derived in 5.1.1. Forretarders which have driver controls available to select incremental levels of retarding power, multiple listingsof power for each engine speed
44、 may be shown for each of the settings available.5.1.3 DRIVELINE RETARDER POWERValues for the driveline retarders power shall be listed, per manufacturersupplied data, at the four driveline speeds which correspond to the range of vehicle and engine speedsderived in 5.1.1. For retarders which have dr
45、iver controls available to select incremental levels of retardingpower, multiple listings of power may be shown for each of the settings available. In those cases wheresubstantial downhill operation is envisioned with a driveline retarder known to exhibit time-dependent powerdecay characteristics, m
46、ultiple sets of power data may be included at time increments corresponding to 5,10, and 20 minutes of continuous retarder operation. In turn, multiple calculations may be made anddisplayed to show the time history power absorption, and thus vehicle control speed characteristics of thistype of retar
47、der.5.1.4 TRAILER AXLE RETARDER POWERValues for the trailer-axle retarders power shall be listed, permanufacturer supplied data, at trailer-axle speeds which correspond to the range of vehicle speeds derivedin 5.1.1. For retarders which have driver controls available to select incremental levels of
48、retarding power,multiple listings of power may be shown for each of the settings available. In those cases where substantialdownhill operation is envisioned with a trailer-axle retarder known to exhibit time-dependent power decaycharacteristics, multiple sets of power data may be included at time in
49、crements corresponding to 5, 10, and20 min of continuous retarder operation. In turn, multiple calculations may be made and displayed to showthe time history power absorption, and thus vehicle control speed characteristics of this type of retarder.5.1.5 VEHICLE NATURAL RETARDATIONThe vehicles inherent retarding power is a function of its speed, the roadsurface on which it is operated, its weight, properties of its tires, its frontal area, aerodynamic drag, ambient
