Demonstration of particulate matter characterization from HVO-blended diesel using an integrated multi-instrument approach.

We demonstrate the methodology to investigate particulate matter (PM) emissions from a 7 V/V% hydrotreated vegetable oil-diesel fuel blend (HVO7) compared to conventional diesel (B0) using a state-of-the-art integrated real-time measurement system. The methodology combines photoacoustic spectroscopy (using our custom photoacoustic (PA) instrument incorporating deep UV wavelengths, which is crucial for characterizing the organic matter content of exhaust PM), particle sizing, and thermal treatment to provide comprehensive, in situ characterization of PM across different engine loads and temperatures. We present size distribution and spectral measurements coupled with a thermodenuder that enables volatility-based classification of PM, allowing evaluation of spectral responses with respect to particle size variations and the dynamic black carbon (BC) to organic matter (OM) ratio in exhaust emissions. Our results show that HVO7 reduces particle number concentrations compared to B0, particularly under low-load conditions; however, these reductions gradually diminish at higher engine loads. Spectral measurements show that the HVO-blended fuel produces less black carbon than B0 at all engine loads and lower TD temperatures, with HVO7 exhibiting higher sensitivity to engine operating conditions than B0. The proposed integrated methodology offers a robust framework for real-time PM analysis of fuel emission, and the results demonstrate the potential of HVO blends to mitigate PM emissions, contributing to sustainable fuel development and emission control strategies.