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Industry News

EMI by the Dashboard Light

July 9, 2011
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As the automobile industry bounces back from the great recession, manufacturers are designing their next generation of cars with an eye on fuel economy and telematics (information and communication technologies). Increasingly, the cars being designed today represent the latest frontier in the wireless revolution. While luxury cars have been integrating RF/microwave sensors, navigation and communication systems for several years now, delivering enhanced safety, traffic management and in-car entertainment through car-to-car and car-to-network communication is on the rise in cars of all prices.

At Mobile World Congress last February, chip maker Qualcomm announced a partnership with Audi to develop capability that would provide a “bubble of connectivity” for travelers, allowing them to access web-based services at high speeds of travel. The Audi A8 will feature the Mobile Media Interface Plus in-car navigation system, which will act as a mobile “hotspot,” enabling passengers to connect Wi-Fi enabled devices to the Internet.

The satellite navigation system will have Google Earth built-in, providing drivers with high resolution, three-dimensional satellite imagery. Audi has stated that the system, when combined with a street atlas and other online content, can provide real-time route planning, location-specific points of interest or local restaurant reviews, as well as up-to-the-minute traffic information. The system utilizes Qualcomm’s UMTS technology to provide the high speed data network that will make it possible for Internet-enabled devices to connect to the web while moving at highway speeds. Audi said the first UMTS-enabled A8s would go on sale later this year.

Ford has also been at the forefront of developing market leading telematics and infotainment services for its vehicles. This wireless connectivity is being driven in part by the challenges of introducing a fleet of electric cars to a market that has evolved around petroleum-fueled vehicles.  In March, Ford Motor Co. and AT&T announced their collaboration to wirelessly connect Ford’s first all-electric passenger car. Using an embedded AT&T wireless connection and the “MyFord” mobile smartphone app, vehicle owners will be able to send and receive data about their electric car, providing command and control of vehicle settings remotely. This will enable owners to plan trips, monitor the vehicle’s state of charge, receive various alerts for vehicle charging, as well as other features designed to support electric vehicle ownership.

Ford also unveiled a new range of specialized car-to-car WiFi networks intended to allow cars to automatically negotiate following distances and lane changes in an effort to avoid potential traffic hazards. According to the automaker, the technology works over a short-range WiFi system on a secure channel allocated by the FCC and allows 360 degree traffic coverage even without direct line of sight. This latest implementation of “collision avoidance radar” includes predicting collision courses with unseen vehicles, seeing sudden stops, and spotting traffic pattern changes.

With the introduction of wireless systems and the increase in the vehicle electronics, electromagnetic interference (EMI) problems understandably are on the rise. EMI issues range from on-board AM and FM radio interference to catastrophic failure of an engine control module due to power transients. EMI has been considered a potential cause of the recent inexplicable acceleration of certain Toyota models. The problems are expected to get worse as system clock speeds and logic edge rates increase, due to increased EMI emissions and decreased EMI immunity.

Vehicle electrical systems are a rich source of power transients. Seven of the most severe have been characterized and have become a suite of standard EMI test pulses, as described in SAE J1113, “Electromagnetic Susceptibility Procedures for Vehicle Components.’’ These transients include pulses that simulate both normal and abnormal conditions, including inductive load switching, ignition interruption or turnoff, voltage sag during engine starting, and the alternator “load dump’’ transient.

With vehicles acting as a platform for land mobile radio transmitters, the onboard electronics systems also may be exposed to very high radio frequency (RF) electromagnetic field levels and can even be exposed to high levels from external threats, such as high powered radio stations or airport radar systems that can easily reach 50 ±100 Volts/meter. Since typical failure levels for unprotected electronic systems are in the 1 ±10 Volt/meter range, substantial RF protection must be provided for electronic systems operating in the automotive environment.

Designing the next generation of automotive telematics in such a hostile electrical environment requires engineering tools and techniques that can help identify and mitigate EMI problems. This month’s cover feature includes three invited papers from a few leaders in the area of automotive EMI simulation and test systems – ANSYS, CST and ETS-Lindgren. Each author was asked to provide an update on the challenges for integrated wireless systems into the next generation of automobiles and recent changes to their tools that will help address EMI by the dashboard light.

Recent Articles by David Vye, Microwave Journal Editor

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