Researchers have created new techniques for measuring emissions from category-L vehicles under real-world conditions and determining appropriate limit values.
As part of an international project consortium, TU Graz has developed new measurement techniques and methods to measure emissions from category-L vehicles in realistic operation and to determine corresponding limit values.
The automotive emissions scandal that emerged in 2015 triggered significant changes within the industry. One of the key discussions has been about the necessity of conducting realistic emissions tests on vehicles, as opposed to relying solely on tests performed in controlled environments. While such tests and emission limits have become mandatory for cars, they still do not apply to category-L vehicles, which include mopeds, motorcycles, tricycles, and quads. Through the “LENS” project (L-vehicles Emissions and Noise mitigation Solutions), funded by the European Commission, Graz University of Technology (TU Graz) and its international partners have developed appropriate testing procedures and equipment. The outcomes of this project will inform lawmakers for future regulations, equip enforcement authorities to identify emissions violators and tampered vehicles, and allow manufacturers to adjust their fleets accordingly.
Unique global methodology and technology
“The measurement techniques developed for cars over recent years are not suitable for the more dynamic category-L vehicles,” explains Stephan Schmidt from the Institute of Thermodynamics and Sustainable Propulsion Systems at TU Graz. “This necessitated the creation of new measuring methods and further refinement of compact, lightweight measurement devices appropriate for motorcycles and mopeds. The developed measurement techniques and the emissions data gathered are unparalleled worldwide.” The project includes 15 partners, consisting of nine research organizations, four two-wheeler manufacturers, and producers of measurement technologies.
During the “LENS” initiative, the project team tested a total of 150 vehicles, both on the road and in laboratories, with 40 of those tests conducted at TU Graz. The measurement methodology and certain measurement technologies for all project participants were collaboratively developed by the Institute of Thermodynamics and Sustainable Propulsion Systems and the Institute of Electrical Measurement and Sensor Systems. Crafting suitable route profiles for testing various category-L vehicles posed a significant challenge, especially since an easy-to-handle scooter differs greatly from a powerful motorcycle. Ultimately, a balanced selection of route types, including both challenging and gentle areas, was established, accounting for diverse classes of vehicles and driving styles. The diversity in drive systems, outputs, and vehicle weights demanded an adaptive measurement approach for different subclasses. Accurate measurement of exhaust gas mass flow is vital for emissions calculation, but conventional methods struggle with small-volume single-cylinder engines. The solution came from TU Graz’s model-based mass flow measurement method, which allows for estimating mass flow from test bench data and applies these models to real-world journeys, yielding valuable emission data from the compact measuring devices.
“The various engine designs and performance levels in the category-L vehicle sector pose challenges in establishing standardized testing methods for accurately assessing noise and emissions,” remarks Stephan Schmidt. “Nonetheless, through the LENS project, we have accomplished this, enabling our consortium to provide manufacturers, regulators, and enforcement agencies the technical foundation to evaluate vehicles based on realistic data in the future. This will significantly help reduce pollutant emissions from the category-L vehicle population.”