Advanced wireless micro-sensors to prevent jet, spacecraft and car engine failures

Researchers at Purdue University are teaming with the US Air Force to develop tiny wireless sensors tough enough to survive the harsh conditions inside jet engines to detect when critical bearings are close to failing, shut them down and prevent breakdowns or crashes.

The researchers have shown that the new sensors can detect impending temperature-induced bearing failure significantly earlier than conventional sensors. Jet engine bearings must function amid temperatures of about 300 degrees Celsius, or 572 degrees Fahrenheit, researchers said.  Current sensor technology can withstand temperatures of up to about 210 degrees Celsius, researchers said.  

The sensors could be in use in a few years in military aircraft such as fighter jets and helicopters but the technology also has potential applications in commercial products, including aircraft and cars – anything with an engine. In addition, the sensors could be used in aerospace applications to monitor bearings in satellite attitude control wheels to keep the satellites in position.  The wheels are supported by two bearings. If mission controllers knew the bearings were going bad on a specific unit, they could turn it off and switch to a backup. "What happens, however, is that you don't get any indication of a bearing's imminent failure, and all of a sudden the gyro stops, causing the satellite to shoot out of orbit," said Farshid Sadeghi, a professor of mechanical engineering at Purdue.

Researchers said the new sensors make use of technology known as micro electromechanical systems, or MEMS, which are machines that combine electronic and mechanical components on a microscopic scale.  The new MEMS sensors provide early detection of impending failure by directly monitoring the temperature of engine bearings, whereas conventional sensors work indirectly by monitoring the temperature of engine oil, yielding less specific data, researchers said.

The MEMS devices will not require batteries because power will be provided using a technique called inductive coupling, which uses coils of wire to generate current.  The sensors will transmit temperature data wirelessly."The MEMS technology is critical because it needs to be small enough that it doesn't interfere with the performance of the bearing itself," Sadeghi said.

A research paper from Purdue was presented on the MEMs project at this week’s IEEE Sensors 2007 conference in Atlanta, sponsored by the Institute of Electrical and Electronics Engineers.   

Copyright © 2007 IDG Communications, Inc.

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