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Physical Science Laboratory, Delphi Automotive Systems combine efforts to develop test facility for automotive sensors

Shawn Worrell of Delphi Automotive Systems, left, and Thomas Greenling of NMSU's Physical Science Laboratory position antennae within a shielded chamber that is used in electromagnetic compatibility testing.

NMSU photo by Michael Kiernan

The Physical Science Laboratory (PSL) at New Mexico State University has teamed up with Delphi Automotive Systems to test automotive sensors that are critical to the safe and efficient operation of cars and trucks.

The new Electromagnetic Compatibility (EMC) Test Facility at PSL was custom-designed to test Delphi sensors to make sure they are immune to interference from electromagnetic fields a vehicle may encounter -- whether the signals are coming from an airport's radar or from a cellular telephone in a passing car.

The rigorous testing also assures that the sensors do not emit unacceptable electromagnetic fields of their own.

"As the radio frequency spectrum has become more populated, the need for EMC testing has accelerated," said Shawn Worrell, who is responsible for EMC testing at Delphi's Mexico Technical Center in Juarez. "In the automotive industry, this kind of testing must be performed in order to ensure that the vehicle will operate properly in an EMI (electromagnetic interference) environment."

Today's vehicles rely on electronic systems to perform a multitude of tasks, and these systems in turn depend on sensors to feed them critical information. "How fast is each of the wheels turning?" The vehicle's antilock brake system (ABS) wants to know that, and wheel speed sensors provide constant feedback.

"What are the exact positions of the engine's crankshaft and camshafts?" Electronic ignition and fuel injection systems need to know this for efficient performance. Improper timing can cause poor performance, increased fuel consumption and pollution, so it's important that crank and cam position sensors do their jobs well.

In a 12-by-16-foot galvanized steel box, known as a reverberation chamber, Delphi sensors are subjected to electromagnetic fields at frequencies and power levels that simulate the worst conditions a vehicle might encounter, to make sure the sensors continue to function properly under those conditions. Because most electrical devices emit an electromagnetic field, the sensors also are tested for radiated emissions to assure that their emissions are within acceptable levels and do not interfere with the vehicle's other electronic systems.

The chamber, located in PSL's Anderson Hall on the NMSU main campus, is shielded to keep any signals from entering or leaving the box during a test. The controlled environment is crucial for the stringent testing required for components that are essential to a vehicle's performance and function.

The EMC Test Facility is the result of a joint effort started more than 18 months ago by Delphi Automotive Systems, represented by Worrell, and Russell Jedlicka, manager of PSL's Electromagnetic Systems branch. Hardware integration was overseen by PSL Senior Engineer Thomas Greenling and supported by personnel from the Delphi EMC Test Facility in Anderson, Ind.

"Our engineering organization at Delphi decided it wanted to establish local testing capability, either at our technical center in Juarez or somewhere close," Worrell said. When Delphi engineers checked on existing capabilities in the area, he said, they found that PSL had extensive experience in electromagnetic systems work with the U.S. Department of Defense.

Delphi has invested about $400,000 in the testing laboratory, and Worrell now divides his time between the NMSU campus and Delphi's Juarez facility.

"It has been a joint effort," Jedlicka said. "We hope to have student involvement in the day-to-day operation of the test facility."

With 200,000 employees, Delphi is the world's largest automotive supplier. Worrell said the company makes components for most of the major auto manufacturers, including General Motors, Ford, BMW, Volkswagen, Fiat and Isuzu. Delphi is owned by GM, but a portion of the company's stock was sold in an initial public offering (IPO) in February and there are plans to complete the spinoff by the end of this year.

Karl Hill