All new vehicles sold in Europe are fitted with European onboard diagnostics (EOBD) devices, which monitor engine emissions and compare them with predefined fault thresholds. These devices report faults using dashboard indicators or diagnostic codes relayed to service technicians. Developing the calibration for the diagnostics systems requires extensive access to prototype vehicles to measure their performance characteristics. Engineers analyze these characteristics and use the results to program the diagnostic system to recognize emissions errors while ignoring other unrelated fluctuations in engine performance.
"The ease of use and statistical analysis within the Model-Based Calibration Toolbox gives the user the opportunity to accurately evaluate many model inputs quickly," said Nick Wright, engineer at Ford. "Working with The MathWorks tools has made a big difference to the engineers working in EOBD calibration. The tools developed have made many of the standard calibration tasks quicker and easier for the engineer to complete with no compromise on the quality of the output."
The MathWorks tools enabled Ford engineers to streamline the process of EOBD calibration. Ford's previous calibration methods required precise measured data at all operating points to fill calibration maps. Using the Model-Based Calibration Toolbox and design of experiments (DOE) tools they developed test plans that take the most critical test points, substantially reducing testing requirements. They then used the statistical modeling capabilities of the toolbox to create accurate and robust multidimensional models of the system throughout the operating range.
Engineers generated and optimized calibration maps and populated calibration tables. Rather than evaluate and refine the calibration with physical testing, Ford imported the calibration and test data into a Simulink model and then simulated the model using input signals acquired while collecting the original test data. Engineers can optimize and re-evaluate calibrations on the desktop, comparing results from different simulations to see the effect of calibration changes.
Ford is currently extending the use of MathWorks tools to other aspects of engine calibration, including exhaust and cooling systems. As a result of the EOBD project, Ford now has reusable models of engine control-unit behavior, which can eliminate the need for new test data for some future developments.
"The MathWorks tools were created to make engineers' jobs more efficient," said Paul Barnard, marketing director for Control Design Automation, The MathWorks. "By using these tools and Model-Based Design, Ford engineers have been able to achieve their primary goal of streamlining a very time-consuming, costly process, while at the same time producing the same high-quality products they are known for."
About The MathWorks
The MathWorks is the world's leading developer of technical computing software for engineers and scientists in industry, government, and education. With an extensive product set based on MATLAB and Simulink, The MathWorks provides software and services to solve challenging problems and accelerate innovation in automotive, aerospace, communications, financial services, biotechnology, electronics, instrumentation, process, and other industries.
The MathWorks was founded in 1984 and employs more than 1,000 people worldwide, with headquarters in Natick, Massachusetts. For additional information, visit www.mathworks.com.
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