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Thursday, February 25, 2010

is EMI to blame for recent Toyota problems?

News outlets and internet blogs abound this week with stories speculating that the problems with some reported out of control vehicles may be related to EMI.

Anyone involved with Electromagnetic Compatibility will recognize that given the proliferation of technology in today’s automobiles, the conditions do exist for catastrophic failure of sensitive systems, and the potential is high for injury or death if such systems fail.

In traditional “analog” systems, these failures would tend to manifest in the form of glitches, or other minor system anomalies. Problems have been reported in the past with CB radio systems causing the electronic fuel injection to fail, causing the car to stall. More recently, and as systems are becoming more advanced, problems have been reported that cell phone calls have interfered with sensors causing the inadvertent operation of breaking systems.

In some of today’s vehicles however, with technology so advanced and systems so integrated into every aspect of the vehicles operation, it is virtually complete “fly-by-wire”. One can imagine the potential for disaster. Several groups exist that contain engineers devoted to such “imagination”, such as the SAE International, the IEEE and the ISO/IEC to name a few. Today, all major automakers have internal production controls and standards focused on Electromagnetic Compatibility, and most have been testing vehicles and systems for a couple of decades.

With many consumer electronic devices finding their way into the automobile, as well as cell phones and wireless headsets, the potential for interference is ever increasing. Automakers will need to address an ever changing EM environment.

With cost cutting measures driving the market, component suppliers are faced with tough decisions as to the extent of testing for product off the assembly. EMC testing is expensive, and testing everything that rolls off the line is impracticable. Some find, that one sample tested, is suitable to represent hundreds of thousands of units. Others may find that outsourcing testing can save thousands of dollars, but the tradeoff here is that these labs may not operate under the same tight controls as local accredited test labs, so the uncertainty in the results may be too high.

It is in fact not possible to know if EMI is the cause of a particular incident without extensive research and testing, it would seem that the phenomenon would be on the short list of suspects for now, however.

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