LENS partner TU Graz recently published the deliverable D3.3 Optimised on-board measurement system including PN2.5 sensor, which summarises the development of an advanced on-board measurement system designed to detect ultra-fine particle emissions. This system, combines Condensation Particle Counter (CPC) and Diffusion Charging (DC) technologies, improving upon existing commercial sensors that struggle with either detecting small particles or managing high concentrations. The study highlights the limitations of current sensors and the necessity of a more efficient and portable solution for on-road applications.
The deliverable discusses the theoretical modelling and laboratory validation of the PN 2.5 nm sensor, focusing on the selection of an appropriate working fluid. Diethylene Glycol was identified as a suitable fluid due to its low vapour pressure and ability to enhance particle detection without excessive droplet growth. Simulations and experiments confirmed the effectiveness of this approach, demonstrating accurate particle detection even at high concentrations.
Laboratory experiments validated the sensor’s performance against reference instruments, proving its capability to measure high particle concentrations. The integration of a diffusion charger enhanced detection limits, while modifications to the working fluid and condensation chamber improved accuracy. Tests conducted on a chassis dynamometer further confirmed the system’s feasibility for real-world applications, though challenges such as response time and concentration limits require further refinement.
The report concludes that while the developed PN2.5nm sensor represents a significant advancement in emission measurement, further improvements are necessary. Future efforts will focus on refining calibration techniques, enhancing the sensor’s robustness for on-road use, and integrating a dilution system to extend its measurement range. The findings contribute to the ongoing effort to improve air quality monitoring and regulatory compliance for vehicle emissions.