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.QUESTIONS REGARDING THIS DOCUMENT: (412) 772-8512 FAX: (412) 776-0243TO PLACE A DOCUMENT
3、 ORDER; (412) 776-4970 FAX: (412) 776-0790Copyright 1978 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 StandardJ1211REV.NOV78Issued 1978-06
4、Revised 1978-11Superseding J1211 JUN78RECOMMENDED ENVIRONMENTAL PRACTICES FOR ELECTRONIC EQUIPMENT DESIGNForewordThis Document has not changed other than to put it into the new SAE Technical Standards BoardFormat.1. PurposeThis guideline is intended to aid the designer of automotive electronic syste
5、ms and components byproviding material that may be used to develop environmental design goals.1.1 ScopeThe climatic, dynamic, and electrical environments from natural and vehicle-induced sources thatinfluence the performance and reliability of automotive electronic equipment are included. Test metho
6、ds thatcan be used to simulate these environmental conditions are also included in this document.The information is applicable to vehicles that meet all the following conditions and are operated on roadways:1.1.1 Front engine rear wheel drive vehicles.1.1.2 Vehicles with reciprocating gasoline engin
7、es.1.1.3 Coupe, sedan, and hard top vehicles.Part of the information contained herein is not affected by the above conditions and has more universalapplication. Careful analysis is necessary in these cases to determine applicability.2. References2.1 Applicable PublicationsThe following publications
8、form a part of the specification to the extent specifiedherein. Unless otherwise indicated the latest revision of SAE publications shall apply.2.1.1 SAE PUBLICATIONSAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE J400 JUL68Recommended Practice Test for Chip Resistance of Su
9、rface CoatingsSAE J726bAir Cleaner Test CodeSAEJ1113aElectromagnetic Susceptibility Procedures for Vehicle Components (Except Aircraft) (June,1978)Paper740017O. T. McCarter, “Environmental Guidelines for the Designer of Automotive ElectronicComponents” (Presented at SAE Automotive Engineering Congre
10、ss, Detroit, March 1974)Paper730045G. B. Andrews, “Control of the Automotive Electrical Environment” (Presented at the SAEAutomotive Engineering Congress, Detroit, January 1973)SAE J1211 Revised NOV78-2-2.1.2 OTHER PUBLICATIONMotorola CER-114O. T. McCarter, “Environmental Guidelines for the Designer
11、 of Automotive ElectronicComponents” (1973)3. Application3.1 Environmental Data and Test Method ValidityThe information included in the following sections is basedupon test results achieved by major North American automobile manufacturers and automobile originalequipment suppliers. Operating extreme
12、s were measured at test installations normally used by manufacturersto simulate environmental extremes for vehicles and original equipment components. They are offered as adesign starting point. Generally, they cannot be used directly as a set of operating specifications becausesome environmental co
13、nditions may change significantly with relatively minor physical location changes. Thisis particularly true of vibration, engine compartment temperature, and electromagnetic compatibility. Actualmeasurements should be made as early as practical to verify these preliminary design baselines.The propos
14、ed test methods are either currently used for laboratory simulation or are considered to be arealistic approach to environmental design validation. They are not intended to replace actual operational testsunder adverse conditions. The recommended methods, however, describe standard cycles for each t
15、ype oftest. The designer must specify the number of cycles over which the equipment should be tested. The numberof cycles will vary depending upon equipment, location, and function. While the standard test cycle isrepresentative of an actual short term environmental cycle, no attempt has been made t
16、o equate this cycle toan acceleration factor for reliability or durability. These considerations are beyond the scope of this guideline.3.2 Organization of Test Methods and Environmental Extremes InformationThe data presented in thisdocument is contained in Sections 4 and 5. Section 4, Environmental
17、 Factors and Test Methods, describes the11 major characteristics of the expected environment that have an impact on the performance and reliability ofautomotive electronic systems. These descriptions are titled:3.2.1 Temperature.3.2.2 Humidity.3.2.3 Salt Spray Atmosphere.3.2.4 Immersion and Splash (
18、Water, Chemicals, and Oils).3.2.5 Dust, Sand, and Gravel Bombardment.3.2.6 Altitude.3.2.7 Mechanical Vibration.3.2.8 Mechanical Shock.3.2.9 Factors Affecting the Automotive Electrical Environment.3.2.10 Steady State Electrical Characteristics.SAE J1211 Revised NOV78-3-3.2.11 Transient, Noise, and El
19、ectrostatic Characteristics.They are organized to cover three facets of each factor:a. Definition of the factor.b. Description of its effect on control, performance, and long term reliability.c. A review of proposed test methods for simulating environmental stress.Section 5, Environmental Extremes b
20、y Location, summarizes the anticipated limit conditions at five generalcontrol sites:a. Underhood1. Engine2. Bulkhead - dash panelb. Chassisc. Exteriord. Interior1. Instrument Panel2. Floor3. Rear Decke. Trunk3.3 Combined EnvironmentsThe automotive environment consists of many natural and induced fa
21、ctors.Combinations of these factors are present simultaneously. In some cases, the effect of a combination of thesefactors is much more serious than the effect of exposing samples to each environmental factor in series. Forexample, the suggested test method for humidity includes both high and low te
22、mperature exposure. Thiscombined environmental test is very important to components whose proper operation is dependent on sealintegrity. Temperature and vibration is a second combined environmental test that can be significant to somecomponents. During design analysis, a careful study should be mad
23、e to determine the possibility of designsusceptibility to a combination of environmental factors that could occur at the planned mounting location. Ifthe possibility of susceptibility exists, a combined environmental test should be considered.3.4 Test SequenceThe optimum test sequence is a compromis
24、e between two considerations:3.4.1 The order in which the environmental exposures will occur in operational use.3.4.2 A sequence that will create a total stress on the sample that is representative of operation stress.The first consideration is impossible to implement in the automotive case, since e
25、xposures occur in a randomorder. The second consideration prompts the test designer to place the more severe environments last.Many sequences that have been successful follow this general philosophy, except that temperature cycle isplaced first in order to condition the sample mechanically.SAE J1211
26、 Revised NOV78-4-4. Environmental Factors And Test Methods4.1 Temperature4.1.1 DEFINITIONThermal factors are probably the most pervasive environmental hazard to automotive electronicequipment. Sources for temperature extremes and variations include:4.1.1.1 The vehicles climatic environment, includin
27、g the diurnal and seasonal cycles. Additionally, variations inclimate by geographical location must be considered. In the most adverse case, the vehicle that spendsthe winter in Canada may be driven in the summer in the Arizona desert. Temperature variations due tothis source range from 40 80 C (40
28、185 F).4.1.1.2 Heat sources and sinks generated by the vehicles operation. The major sources are the engine and drivetrain components, including the brake system. Very wide variations are to be found during operation. Forinstance, temperatures on the surface of the engine can range from the cooling
29、systems 88 650 C(190 1200 F) on the surface of the exhaust system. This category also includes conduction, convection,and radiation of heat due to various modes of vehicle operation.4.1.1.3 Self-heating of the equipment due to its own internal dissipation. A design review of the worst casecombinatio
30、n of peak ambient temperature (due to 4.1.1.1 and 4.1.1.2 above) minimized heat flow awayfrom the equipment and peak applied steady state voltage should be conducted.4.1.1.4 Vehicle operational mode and actual mounting location. Measurements should be made at the actualmounting site during the follo
31、wing vehicular conditions while subjected to the maximum heat generated byadjacent equipment and at a maximum ambient environment:4.1.1.4.1 Engine start.4.1.1.4.2 Engine idle.4.1.1.4.3 Engine high speed.4.1.1.4.4 Engine Turn OffPrior history important.4.1.1.4.5 Various engine/road load conditions.4.
32、1.1.5 Ambient conditions before installation due to storage and transportation extremes. Shipment in unheatedaircraft cargo compartments may lower the minimum storage (non-operating) temperature to 50C (58F).The thermal environmental conditions that are a result of these conditions can be divided in
33、to threecategories:4.1.1.5.1 ExtremesThe ultimate upper and lower temperatures the equipment is expected to experience.4.1.1.5.2 CyclingThe cumulative effects of temperatures cycling within the limits of the extremes.SAE J1211 Revised NOV78-5-4.1.1.5.3 ShockRapid change of temperature. Figure 1 illu
34、strates one form of vehicle operation which inducesthermal shock. Thermal shock is also induced when equipment at elevated temperature is exposed tosudden rain or road splash.The automotive electronic equipment designer is urged to develop a systematic, analytic method fordealing with steady state a
35、nd transient thermal analysis. The application of many devices containingsemi-conductors will be temperature limited. For this reason, the potential extreme operating conditionsfor each application must be scrutinized to avoid later field failure.FIGURE 1VEHICLE COLD WEATHER WARM-UP CHARACTERISTICS4
36、.1.2 EFFECT ON PERFORMANCEThe damaging effects of thermal shock and thermal cycling include:4.1.2.1 Cracking of printed circuit board or ceramic substrates.4.1.2.2 Thermal stress or fatigue failures of solder joints.4.1.2.3 Delamination of printed circuit board and other interconnect system substrat
37、es.4.1.2.4 Seal failures, including the breathing action of some assemblies, due to temperature-induced dimensionalvariation which permit intrusion of liquid or vapor borne contaminants.4.1.2.5 Failure of circuit components due to direct mechanical stress caused by differential thermal expansion.4.1
38、.2.6 The acceleration of chemical attack on interconnects, due to temperature rise, can result in progressivedegradation of circuit components, printed circuit board conductors, and solder joints.In addition to this, high temperature extremes can cause a malfunction by:SAE J1211 Revised NOV78-6-4.1.
39、2.7 Exceeding the dissociation temperature of surrounding polymer or other packaging components.4.1.2.8 Carbonization of packaging materials with eventual progressive failure of the associated passive or activecomponents. This is possible in cases of extreme overtemperature. In addition, non-catastr
40、ophic failure ispossible due to electrical leakage in the resultant carbon paths.4.1.2.9 Changes in active device characteristics with increased heat including changes in gain, impedance,collector-base leakage, peak blocking voltage, collector-base junction second breakdown voltage, etc.,with temper
41、ature.4.1.2.10 Changes in passive device characteristics such as permanent or temporary drift in resistor value andcapacitor dielectric constants with increased temperature.4.1.2.11 Changes in interconnect and relay coil performance due to the conductivity temperature coefficient ofcopper.4.1.2.12 C
42、hanges in the properties of magnetic materials with increasing temperature, including Curie point effectsand loss of permanent magnetism.4.1.2.13 Dimensional changes in packages and components leading to separation or subassemblies.4.1.2.14 Changes in the strength of soldered joints due to changes i
43、n mechanical characteristics of the solder.Further, low temperature extremes can cause failure due to:4.1.2.15 The severe mechanical stress caused by ice formation in moisture bearing voids or cracks.4.1.2.16 The very rapid and extreme internal thermal stress caused by applying maximum power to semi
44、-conductoror other components after extended cold soak under aberrant operating conditions such as 24-V batteryjumper starts.4.1.3 RECOMMENDED TEST METHODS4.1.3.1 Temperature Cycle TestA recommended thermal cycle profile is shown in Figure 2 and recommendedextreme temperatures in Table 1. The test m
45、ethod of Figure 2A, a 24-h cycle, offers longer stabilizationtime and permits a convenient room ambient test period. Figure 2B, an 8-h cycle, provides moretemperature cycles for a given test duration. It is applicable only to modules whose temperatures willreach stabilization in a shorter cycle time
46、. Stabilization should be verified by actual measurements.Thermocouples, etc.Separate or single test chambers may be used to generate the temperature environment described by thethermal cycles. By means of circulation, the air temperature should be held to within 2.8 C (5 F) ateach of the extreme te
47、mperatures. The test specimens should be placed in such a position, with respect tothe air stream, that there is substantially no obstruction to the flow of air across the specimen. If two testspecimens are used, care must be exercised to assure that the test samples are not subjected totemperature
48、transition rates greater than that defined in Figure 2. Direct heat conduction from thetemperature chamber heating element to the specimen should be minimized.Electrical performance should be measured under the expected operational minimum and maximumextremes of excitation, input and output voltage
49、and load at both the cold and hot temperature extremes.These measurements will provide insight into electrical variations with temperature.SAE J1211 Revised NOV78-7-Thermal shock normally expected in the automotive environment is simulated by the maximum rates ofchange shown on the recommended thermal cycle profile shown in Figure 2. The proper thermal shockcycle should be determined by analysis of component power dissipation, expected rate of temperaturechange at its location in the system and the overall ambient operating temperature. In general
