Going to wide open throttle is a failure mode that is identified in failure analysis. The failure can be detected in software and there would be different layers to it he says. With the system recognizing the wide open throttle condition and the actuator not responding to a command to go back to closed throttle, different steps can be taken. First of all, the power to the device can be turned off through the software. Then mechanically the unit would return to a predetermined position. However, if the unit is jammed and can’t move, the next step is to cut the fuel to the engine -- also through the software. This will definitely cause the vehicle to stop. “It’s better to stop than going wide open throttle until you hit something,” says Bogden. Beside a strategy for the control system, the driver should also almost instinctively know what to do to stop his/her vehicle. Unfortunately, most drivers are not prepared for this situation.

The Impact of EMI on Sensors, Microcontrollers and Other Circuitry

The car companies do a lot of work to characterize their environment. Component level, module level and system level tests are done at a higher level than a vehicle would experience and those tests overlap.  “The component and system level tests are made for developmental tests,” says Muccioli. “The vehicle test is just to validate.” Multiple tests covering the same fields and overlapping environments produce a high confidence level in low EMC at the vehicle level.

Muccioli has performed testing to establish the correlation of EMC problems and solutions. “We got correlation from an emission standpoint from the chip level, to the module level and ultimately when you put the module into the vehicle showing that if you have a noisy microprocessor you can see it all the way to the vehicle level,” he says.  “Also, if you quiet it down, you see the quiet down to the vehicle level.”

EMC testing bombards components with rather strong direct radiation across the spectrum – stronger than what the component would experience when it is mounted in a vehicle says Bogden. “When the semiconductor guys test their parts they can get them to misbehave but they are applying such a strong field directly to the part, it’s probably not what I would consider realistic in the real world,” he says. This level of testing discovers the device’s level of immunity and ensures that it is sufficiently robust.

Changes are occurring in advanced semiconductor technology that impact EMC. The IEEE EMC Society cites a number of hardware trends that can cause increased EMC problems at the device level including:

• The ongoing miniaturization of devices, resulting in smaller gaps in their geometries;
• Lower power consumption, with smaller voltage swings or quieter signals inside the chips;
• Higher clock speeds that are well above 3GHz; and
• Wider bandwidth ports, including WiFi and microwave.

At the same time the society has indentified electromagnetic compatibility trends that include:

• An increasing number of radiators,
• An increasing number of receptors,
• Increasing susceptibility of those receptors,
• Increasing demand for communications, particularly wireless

These trends have increased the need for EMC and those engineers who specialize in this field.

Establishing Expertise

Williams has a recommendation for companies without an internal background for EMI/EMC that have recently identified a need for this expertise. “As in any organization, the number one thing they want to do is hire good people to start with and then support them to be active in participating in their relevant professional community and working with the relevant standards community. If they do that, they are probably going to be well guided in their work,” he says.

Engaging an experienced consulting service such as Jastech EMC Consulting is another way to get expertise immediately and on a periodic basis. The fulltime experts can get a design started so that subsequent EMC problems are minimal. “EMC is not a black magic,” concludes Muccioli.  “You have got to follow a process and if you follow a process, you should be able to catch a majority, if not all of the anomalies.”

Relating National and International Standards

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The process for establishing national and international standards is very straightforward according to Kimball Williams, past president IEEE EMC Society and currently on the board of directors.  “Unfortunately, most people don’t even know it exists,” he laments. Companies frequently develop internal standards for their products because they need to confirm that the product will survive in the real world. Subsequently, the company will contribute to standards at the national committee level. In the automotive industry, that means joining one of the committees under the SAE, since the SAE is the arm of the American National Standards Institute (ANSI) which has been chartered for following and documenting automotive standards for the U.S.

The national committees worldwide join together and contribute to the international standards – all meet together at either the International Electrotechnical Commission (IEC) or the International Standards Organization (ISO). “Right now, for EMC work, the IEC is handling all of the emissions and ISO is handling all of the immunity,” says Williams. The national committees contribute and provide the experts for the international standards development organization and achieve consensus at the international level. Any company that wants to use a national or international standard simply obtains the standard -- some are free, others have a nominal fee and some are a bit more expensive. A company can chose to implement either the national or international standard. “Most contemporary companies that have products that cross borders are tending to move toward the international standards,” says Williams.