Particulate Emission Characterization in Diesel Engines
Summary
The comprehensive study of particulate emissions from diesel engines encompasses the identification, quantification and characterisation of microscopic soot and ash particles formed during combustion and aftertreatment. Researchers employ both mass-based metrics and particle number measurements to capture the full spectrum of emissions, ranging from nanometre-scale ultrafine particles to accumulation-mode soot. Characterisation methods include laboratory-based engine dynamometer tests, portable on-road measurement systems, remote sensing and advanced aerosol instrumentation such as scanning mobility particle sizers and condensation particle counters. Key engineering controls—exhaust gas recirculation, optimised injection strategies and wall-flow diesel particulate filters—have driven mass emission reductions of over 90 per cent in modern fleets. However, the influence of semivolatile organics, sub-23 nm particles and transient driving conditions presents ongoing challenges. Accurate measurement under real-world conditions, coupled with evolving regulatory frameworks targeting particle number and mass, has become critical to assess public health impacts, compliance verification and the development of next-generation diesel technologies.
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Particulate Emission Characterization in Diesel Engines publication trend
The graph below shows the total number of articles in particulate emission characterization in diesel engines across all publications each year (not limited to Nature Index journals).
Technical terms
Particulate Matter (PM): mass-based metric reflecting the total mass of solid and liquid particles suspended in exhaust gases.
Particle Number (PN): count-based metric indicating the number of particles emitted per unit volume or distance.
Diesel Particulate Filter (DPF): wall-flow aftertreatment device designed to trap and oxidise soot particulates from diesel exhaust.
Portable Emission Measurement System (PEMS): mobile instrumentation for on-road, real-time monitoring of exhaust pollutants during normal vehicle operation.
Exhaust Gas Recirculation (EGR): engine control strategy that reintroduces a portion of exhaust gas into the combustion chamber to reduce peak temperatures and nitrogen oxide formation.
Condensation Particle Counter (CPC): analytical instrument that enlarges ultrafine particles via vapour condensation to enable counting and sizing.
References
- Sub-23 nm Particles Dominate Non-Volatile Particle Number Emissions of Road Traffic. Environmental Science and Technology (2023).
- Evaluation of the point sampling method and inter-comparison of remote emission sensing systems for screening real-world car emissions. The Science of The Total Environment (2024).
- Particulate emissions from diesel engines: correlation between engine technology and emissions. Journal of Occupational Medicine and Toxicology (2014).
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