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Engine Emissions

Engine Emissions

Regulators and researchers use TSI particle instruments for engine emissions research around the world. Our products help quantify and analyze particle emissions from light-duty and heavy-duty engines, for both on-road and stationary applications.

You’ll find TSI products used in the research and development of advanced internal combustion engines and after-treatment systems, like Diesel Particulate Filters (DPF) or Gasoline Particulate Filters (GPF). Our particle counters quantify the number concentration of aerosol particles. TSI particle sizers measure the size distribution of exhaust particles. 

Our instruments allow measurements at the tailpipe, from the Constant Volume Sampler (CVS), or from other partial flow samplers. TSI’s fast sizer spectrometers may also enable high time resolution mass measurements of engine exhaust particles.

meeting engine emissions Standards AND Regulations

TSI’s condensation particle counter was the standard reference instrument during the development of the UNECE PMP, the United Nations Economic Commission for Europe Particle Measurement Programme. Its successor, the Engine Exhaust Condensation Particle Counter 3790A, detects nanoparticles larger than 23nm per Euro 5b / Euro 6 regulations. When combined with a diluter and a volatile particle remover, the EECPC measures solid exhaust particles to PMP requirements.

The European Union and other countries such as China and India have regulations (e.g. Euro 6/VI, China 6) for measuring solid particles larger than 23nm. Studies have shown that some newer engine technologies, such as Gasoline Direct Ignition engines, emit solid particles in the 10 to 23nm range. The next phase of particle number regulations (post-Euro 6/VI) will lower the particle size from 23nm to 10nm. TSI’s EECPC 3790A-10 detects particles larger than 10nm.

Other TSI instruments include the Engine Exhaust Particle Sizer (EEPS) 3090 and the new Porous Tube Thermodiluter (PTT) 3098. These provide integrated solutions for accurate measurement of time-resolved particle size distributions. After-treatment filters have particle retention performance that varies by particle size and filter condition or regime. Insight into the details of particle size distribution allows researchers to optimize engine conditions and injection technologies. More comprehensive measurement data helps our customers comply with stringent emission regulations.

Particle count and particle size data is crucial for designing low-emission vehicles. Whether you’re an engine application developer, a DPF or GPF manufacturer, or other automotive engineer, TSI instruments provide data you need to meet your research and compliance goals.


TSI’s Nanoparticle Emission Tester 3795 (NPET) measures nanoparticles in combustion emissions. It is particularly useful for construction machinery, buses, and other vehicles under realistic use conditions. Free-measurement mode allows continuous measurements. Its test cycle is compliant with SR 941.242 and SR 747.201.3. These Swiss regulations apply to non-road mobile machinery and marine engines equipped with particulate filters, respectively.

The High-Concentration NPET 3795-HC measures upstream and downstream of Diesel or Gasoline Particle Filters, cold start emissions, or biomass combustion emissions. Its measurement capabilities go beyond the requirements of the Swiss regulations.

Customers use NPETs for driving tests, but they are also quick and effective tools to test after-treatment systems. As after-treatment systems age, small leaks from internal defects caused by thermal stress may occur well before warranty expiration. The NPET is sensitive enough to measure particle number as opposed to opacity. This means that it is capable of detecting elevated particle number concentrations caused by those small leaks. Enforcement agencies and shops using the NPET can easily identify high-polluting engines with defective after-treatment systems.


Since 2016, TSI has been working with a group of scientists and policy makers from Switzerland, Germany, Belgium and Netherlands to develop a new tester for upcoming PTI programs. The motivation for this new instrument was to have a tool for rapidly verifying if DPFs are performing adequately during the life cycle
of the vehicle and, additionally, to identify high-polluting vehicles with defective DPFs.

In addition to testing specific vehicles, agencies and researchers use TSI instruments for air quality studies in communities. By driving and deploying our counters and engine fast sizers, they can quantify particle concentrations and size distributions from emissions near streets, freeways, ports, and airports.


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