Focus on Electronics
September 2002
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Mitsubishi Electric develops GMR sensors
 Mitsubishi Electric's GMR cam and crank sensors will be manufactured in Japan for OEMs worldwide, with production beginning for the 2003 model year. |
To properly time the ignition sequence in a car and keep it running smoothly, the engine control unit (ECU) needs to know where the cam and crankshaft are in the revolution cycle. Metal targets are incorporated in the cam and crankshaft design that provide variances in the magnetic field for the sensor to read. The sensor reads and digitizes these changes and sends the information to the car's ECU, which uses these data to make timing adjustments to the next ignition spark.
Mitsubishi Electric Corp. has perfected technology for use on cam and crank sensors that improves ignition sequence timing and engine operation efficiency. Available only from Mitsubishi Electric, the company says its giant magnetoresistance (GMR) sensors are more accurate and less sensitive to installation variations compared to conventional cam and crank sensor technologies offered by competitors: Hall effect, magnetoresistance (MR), and anisotropic MR (AMR). Hall effect is the most common technology employed; MR is more precise in its data collection, but less commonly used than Hall effect; and AMR is an even more precise, but less frequently used, technology.
"Mitsubishi Electric's GMR technology provides the quickest and most accurate data collection option now available to OEMs," said Dave McLenaghan, Mitsubishi Electric Automotive America's Account Manager to General Motors Corp. "The characteristics of the GMR element produce a sensor that is more accurate and much less susceptible to errors caused by engine system build variation compared to current technologies."
Mitsubishi Electric, which claims to be the first company to develop the technology for automotive applications, has seen an increase in GMR sensor orders from several OEMs, including some for near-future General Motors vehicle applications. In the late 1990s, while competitors were doubtful of the technology's suitability for cam and crank sensor use, Mitsubishi Electric continued to develop GMR sensors, which its says are more resistant to external factors such as temperature, mounting misalignment, and metal filings. Micromachining has been instrumental in their development, with the sensors being more accurate, thanks to the GMR characteristics, and they exhibit reduced part-to-part variation.
- Kevin Jost
AMI-C, OSGi align specifications
The Automotive Multimedia Interface Collaboration (AMI-C) announced that it is incorporating the Open Services Gateway Initiative (OSGi) technology specification as the underlying framework for its software platform for mobile information and entertainment systems. The AMI-C/OSGi framework will provide one common software platform and open the marketplace for companies wanting to develop wireless automotive applications, benefiting consumers with a wider selection of software applications.
According to AMI-C Chief Software Architect Edward Nelson, the OSGi framework meets AMI-C's requirements and will allow for the remote management of software inside the vehicle, allowing service providers to assist vehicle owners with the configuration and upgrade of software remotely. "This capability (remote management) will allow vehicle owners to easily add common software applications for navigation, traffic information, diagnostics and other services to their vehicles without needing to be computer experts,"said Nelson.
Within the AMI-C software architecture, the OSGi framework provides core capabilities that applications can make use of. The AMI-C layer, which allows developers to write software applications specifically for in-vehicle use, is being built on top of the OSGi framework.
Since OSGi and AMI-C are the leading standards for the wireless automotive services market, this collaboration will now provide service developers a single target for this market, resulting in a much larger pool of applications and services, according to Staffan Truve, VP of Marketing for OSGi, and CEO of Gatespace. "Use of the OSGi framework is also attractive to automakers because it is common to other industries," added AMI-C Program Manager Pom Malhotra.
- Kevin Jost
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