LINK Unites with CARB and ERG to Conduct Brake Emissions Campaign

Automotive emissions regulations inspire technological advancements, more efficient vehicles, and safer and cleaner communities. While particulate matter emissions in exhaust have significantly lessened due to strict controls, non-exhaust emissions remain unregulated and lack commonly accepted test methods. Link Engineering Company is dedicated to providing customized solutions and extensive thought leadership to the testing industry. Through our partnerships, we are leading the testing and research efforts of brake emissions from our very own testing laboratories.

As a customized testing resource, LINK recently joined the California Air Resource Board (CARB) to conduct an extensive brake emissions test campaign and engineering study at our technical center in Dearborn, Michigan. The focus of the campaign was to update CARB's emission factors model for non-exhaust emissions of on-road light-duty vehicles while selecting a sequence that is representative of vehicle usage in the state of California. A significant and unique aspect of the study was also to obtain the ability to differentiate the effects of vehicle type and loading conditions during driving.

The project involved testing brake corners from six vehicles, relying upon approved testing protocols, test system validation, adjustment of cooling airspeeds, and interlaboratory evaluation for filter weighing methods. After conducting market analysis, all selected vehicles underwent rigorous proving ground testing to measure brake and wheel well temperatures, brake pressure, and speed, on top of various garage tests. The final phase consisted of laboratory validation and brake component testing, utilizing LINK's enclosed full-size brake dynamometer and particulate matter sampling systems.

By employing innovative speed control systems, LINK's inertia dynamometer was able to recreate driving representative of usage in California. During each test, LINK's instrument cluster measured the emitted particle count, mass, and size. The regular checks on the test parameters, including the ability of the dynamometer to provide repeatable brake temperatures, produces confidence in the values measured. One aspect unique to this project was the ability to integrate the knowledge obtained from Computational Fluid Dynamics simulation with the University of Michigan. The setup also incorporated recommendations and guidelines from several EPA, U.S. CFRs, and ISO standards, including proper isokinetic sampling.

Lastly, the integration of real-time data from over 100 channels of the instrument cluster helped in creating a new standard for LINK’s ProLINK control and data acquisition software. This new method stores and synchronizes all the data retrieved from the emissions measurement systems, allows data visualization using RevDATA, and enables the automation of the test report without additional manual data processing.

In close collaboration with CARB and the Eastern Research Group (ERG), LINK is coauthoring an SAE technical paper based on this project. The findings from more than 80 tests show the effects of axle position, friction couple formulation, as well as vehicle size, type, and speed. This collection of comprehensive data and reporting will be used to further understand the area of brake emissions. The paper will provide significant insight into the newly developed California Brake Dynamometer Cycle (CDBC) - derived from an extensive database of customer usage on hundreds of vehicles, driving for several thousand miles each - as well as the particulate matter laboratory results tied to running the test cycle. Despite the challenges faced due to the absence of acceptable widespread testing methods, the results obtained in this project will assist in modernizing emission factors globally.

LINK's expertise in researching, executing, and accurately analyzing the mostly unexplored area of brake emissions proves the innovative and technical capabilities we possess for advancing the testing industry. We are dedicated to the growth and evolution of the testing industry, providing innovative solutions that our customers rely on for testing and developing the next generation of equipment and products.

Read more about our brake emissions testing efforts, including our Model 6300 Brake Emissions Test System, on our website.

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