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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 therefr
2、om, 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) 776-0243 TO PLACE A DOCU
3、MENT ORDER; (412) 776-4970 FAX: (412) 776-0790 Copyright 1978 Society of Automotive Engineers, Inc. All rights reserved.Printed in U.S.A. SURFACE VEHICLE 400 Commonwealth Drive, Warrendale, PA 15096-0001 RECOMMENDED PRACTICE Submitted for recognition as an American National Standard J1211 REV. NOV78
4、 Issued1978-06 Revised1978-11 Superseding J1211 JUN78 RECOMMENDED ENVIRONMENTAL PRACTICES FOR ELECTRONIC EQUIPMENT DESIGN ForewordThis Document has not changed other than to put it into the new SAE Technical Standards Board Format. 1.PurposeThis guideline is intended to aid the designer of automotiv
5、e electronic systems and components by providing material that may be used to develop environmental design goals. 1.1ScopeThe climatic, dynamic, and electrical environments from natural and vehicle-induced sources that influence the performance and reliability of automotive electronic equipment are
6、included. Test methods that can 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: 1.1.1Front engine rear wheel drive vehicles. 1.1.2Vehicles with recipr
7、ocating gasoline engines. 1.1.3Coupe, sedan, and hard top vehicles. Part of the information contained herein is not affected by the above conditions and has more universal application. Careful analysis is necessary in these cases to determine applicability. 2.References 2.1Applicable PublicationsThe
8、 following publications form a part of the specification to the extent specified herein. Unless otherwise indicated the latest revision of SAE publications shall apply. 2.1.1SAE PUBLICATIONSAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001. SAE J400 JUL68Recommended Practice Test
9、 for Chip Resistance of Surface Coatings SAE J726bAir Cleaner Test Code SAE J1113aElectromagnetic Susceptibility Procedures for Vehicle Components (Except Aircraft) (June, 1978) Paper 740017O. T. McCarter, “Environmental Guidelines for the Designer of Automotive Electronic Components” (Presented at
10、SAE Automotive Engineering Congress, Detroit, March 1974) Paper 730045G. B. Andrews, “Control of the Automotive Electrical Environment” (Presented at the SAE Automotive Engineering Congress, Detroit, January 1973) SAE J1211 Revised NOV78 -2- 2.1.2OTHER PUBLICATION Motorola CER-114O. T. McCarter, “En
11、vironmental Guidelines for the Designer of Automotive Electronic Components” (1973) 3.Application 3.1Environmental Data and Test Method ValidityThe information included in the following sections is based upon test results achieved by major North American automobile manufacturers and automobile origi
12、nal equipment suppliers. Operating extremes were measured at test installations normally used by manufacturers to simulate environmental extremes for vehicles and original equipment components. They are offered as a design starting point. Generally, they cannot be used directly as a set of operating
13、 specifications because some environmental conditions may change significantly with relatively minor physical location changes. This is particularly true of vibration, engine compartment temperature, and electromagnetic compatibility. Actual measurements should be made as early as practical to verif
14、y these preliminary design baselines. The proposed test methods are either currently used for laboratory simulation or are considered to be a realistic approach to environmental design validation. They are not intended to replace actual operational tests under adverse conditions. The recommended met
15、hods, however, describe standard cycles for each type of test. The designer must specify the number of cycles over which the equipment should be tested. The number of cycles will vary depending upon equipment, location, and function. While the standard test cycle is representative of an actual short
16、 term environmental cycle, no attempt has been made to equate this cycle to an acceleration factor for reliability or durability. These considerations are beyond the scope of this guideline. 3.2Organization of Test Methods and Environmental Extremes InformationThe data presented in this document is
17、contained in Sections 4 and 5. Section 4, Environmental Factors and Test Methods, describes the 11 major characteristics of the expected environment that have an impact on the performance and reliability of automotive electronic systems. These descriptions are titled: 3.2.1Temperature. 3.2.2Humidity
18、. 3.2.3Salt Spray Atmosphere. 3.2.4Immersion and Splash (Water, Chemicals, and Oils). 3.2.5Dust, Sand, and Gravel Bombardment. 3.2.6Altitude. 3.2.7Mechanical Vibration. 3.2.8Mechanical Shock. 3.2.9Factors Affecting the Automotive Electrical Environment. 3.2.10 Steady State Electrical Characteristics
19、. SAE J1211 Revised NOV78 -3- 3.2.11 Transient, Noise, and Electrostatic 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 simul
20、ating environmental stress. Section 5, Environmental Extremes by Location, summarizes the anticipated limit conditions at five general control sites: a.Underhood 1.Engine 2.Bulkhead - dash panel b.Chassis c.Exterior d.Interior 1.Instrument Panel 2.Floor 3.Rear Deck e.Trunk 3.3Combined EnvironmentsTh
21、e automotive environment consists of many natural and induced factors. Combinations of these factors are present simultaneously. In some cases, the effect of a combination of these factors is much more serious than the effect of exposing samples to each environmental factor in series. For example, t
22、he suggested test method for humidity includes both high and low temperature exposure. This combined environmental test is very important to components whose proper operation is dependent on seal integrity. Temperature and vibration is a second combined environmental test that can be significant to
23、some components. During design analysis, a careful study should be made to determine the possibility of design susceptibility to a combination of environmental factors that could occur at the planned mounting location. If the possibility of susceptibility exists, a combined environmental test should
24、 be considered. 3.4Test SequenceThe optimum test sequence is a compromise between two considerations: 3.4.1The order in which the environmental exposures will occur in operational use. 3.4.2A sequence that will create a total stress on the sample that is representative of operation stress. The first
25、 consideration is impossible to implement in the automotive case, since exposures occur in a random order. 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 c
26、ycle is placed first in order to condition the sample mechanically. SAE J1211 Revised NOV78 -4- 4.Environmental Factors And Test Methods 4.1Temperature 4.1.1DEFINITIONThermal factors are probably the most pervasive environmental hazard to automotive electronic equipment. Sources for temperature extr
27、emes and variations include: 4.1.1.1The vehicles climatic environment, including the diurnal and seasonal cycles. Additionally, variations in climate by geographical location must be considered. In the most adverse case, the vehicle that spends the winter in Canada may be driven in the summer in the
28、 Arizona desert. Temperature variations due to this source range from 40 80 C (40 185 F). 4.1.1.2Heat sources and sinks generated by the vehicles operation. The major sources are the engine and drive train components, including the brake system. Very wide variations are to be found during operation.
29、 For instance, temperatures on the surface of the engine can range from the cooling 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. 4.1.1.3Self-heating of the equi
30、pment due to its own internal dissipation. A design review of the worst case combination of peak ambient temperature (due to 4.1.1.1 and 4.1.1.2 above) minimized heat flow away from the equipment and peak applied steady state voltage should be conducted. 4.1.1.4Vehicle operational mode and actual mo
31、unting location. Measurements should be made at the actual mounting site during the following vehicular conditions while subjected to the maximum heat generated by adjacent 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
32、.1.4.4Engine Turn OffPrior history important. 4.1.1.4.5 Various engine/road load conditions. 4.1.1.5Ambient conditions before installation due to storage and transportation extremes. Shipment in unheated aircraft cargo compartments may lower the minimum storage (non-operating) temperature to 50C (58
33、F). The thermal environmental conditions that are a result of these conditions can be divided into three categories: 4.1.1.5.1ExtremesThe ultimate upper and lower temperatures the equipment is expected to experience. 4.1.1.5.2CyclingThe cumulative effects of temperatures cycling within the limits of
34、 the extremes. SAE J1211 Revised NOV78 -5- 4.1.1.5.3ShockRapid change of temperature. Figure 1 illustrates one form of vehicle operation which induces thermal shock. Thermal shock is also induced when equipment at elevated temperature is exposed to sudden rain or road splash. The automotive electron
35、ic equipment designer is urged to develop a systematic, analytic method for dealing with steady state and transient thermal analysis. The application of many devices containing semi-conductors will be temperature limited. For this reason, the potential extreme operating conditions for each applicati
36、on must be scrutinized to avoid later field failure. FIGURE 1VEHICLE COLD WEATHER WARM-UP CHARACTERISTICS 4.1.2EFFECT ON PERFORMANCEThe damaging effects of thermal shock and thermal cycling include: 4.1.2.1Cracking of printed circuit board or ceramic substrates. 4.1.2.2Thermal stress or fatigue fail
37、ures of solder joints. 4.1.2.3Delamination of printed circuit board and other interconnect system substrates. 4.1.2.4Seal failures, including the breathing action of some assemblies, due to temperature-induced dimensional variation which permit intrusion of liquid or vapor borne contaminants. 4.1.2.
38、5Failure of circuit components due to direct mechanical stress caused by differential thermal expansion. 4.1.2.6The acceleration of chemical attack on interconnects, due to temperature rise, can result in progressive degradation of circuit components, printed circuit board conductors, and solder joi
39、nts. In addition to this, high temperature extremes can cause a malfunction by: SAE J1211 Revised NOV78 -6- 4.1.2.7Exceeding the dissociation temperature of surrounding polymer or other packaging components. 4.1.2.8Carbonization of packaging materials with eventual progressive failure of the associa
40、ted passive or active components. This is possible in cases of extreme overtemperature. In addition, non-catastrophic failure is possible due to electrical leakage in the resultant carbon paths. 4.1.2.9Changes in active device characteristics with increased heat including changes in gain, impedance,
41、 collector-base leakage, peak blocking voltage, collector-base junction second breakdown voltage, etc., with temperature. 4.1.2.10Changes in passive device characteristics such as permanent or temporary drift in resistor value and capacitor dielectric constants with increased temperature. 4.1.2.11Ch
42、anges in interconnect and relay coil performance due to the conductivity temperature coefficient of copper. 4.1.2.12Changes in the properties of magnetic materials with increasing temperature, including Curie point effects and loss of permanent magnetism. 4.1.2.13Dimensional changes in packages and
43、components leading to separation or subassemblies. 4.1.2.14Changes in the strength of soldered joints due to changes in mechanical characteristics of the solder. Further, low temperature extremes can cause failure due to: 4.1.2.15The severe mechanical stress caused by ice formation in moisture beari
44、ng voids or cracks. 4.1.2.16The very rapid and extreme internal thermal stress caused by applying maximum power to semi-conductor or other components after extended cold soak under aberrant operating conditions such as 24-V battery jumper starts. 4.1.3RECOMMENDED TEST METHODS 4.1.3.1Temperature Cycl
45、e TestA recommended thermal cycle profile is shown in Figure 2 and recommended extreme temperatures in Table 1. The test method of Figure 2A, a 24-h cycle, offers longer stabilization time and permits a convenient room ambient test period. Figure 2B, an 8-h cycle, provides more temperature cycles fo
46、r a given test duration. It is applicable only to modules whose temperatures will reach stabilization in a shorter cycle time. Stabilization should be verified by actual measurements. Thermocouples, etc. Separate or single test chambers may be used to generate the temperature environment described b
47、y the thermal cycles. By means of circulation, the air temperature should be held to within 2.8 C (5 F) at each of the extreme temperatures. The test specimens should be placed in such a position, with respect to the air stream, that there is substantially no obstruction to the flow of air across th
48、e specimen. If two test specimens are used, care must be exercised to assure that the test samples are not subjected to temperature transition rates greater than that defined in Figure 2. Direct heat conduction from the temperature chamber heating element to the specimen should be minimized. Electri
49、cal performance should be measured under the expected operational minimum and maximum extremes of excitation, input and output voltage 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 of change shown on the recommended thermal cycle profile shown in Figure 2. The proper thermal shock cycle should be determined by analysis of component