Count on it

The AVL Particle Counter (APC) product family measures the concentration of solid particles even under severe conditions. The “x” in the name “xApp” refers to the multiple number of extreme applications the product can handle.

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The continuous reduction of emission limits for particle number (PN) and the global focus on real driving emissions (RDE) has led to complex engine aftertreatment systems and increased development and calibration effort. 
The AVL Particle Counter xApp™ is our state-of-the-art PN product that combines all our particle counting and device application expertise into a single product.
It is a compact and flexible device for the reliable and accurate measurement of solid particle number concentrations. We have designed it to help you calibrate and test your systems under the most severe conditions.

Measuring PN is a requirement for the certification of EURO 6 passenger cars and light commercial vehicles (diesel and gasoline), for EURO VI heavy duty engines, as well as for Real Driving Emission (RDE) legislation.
Research and Development:
PN testing is essential, not only for certification purposes but also at an early stage within the development process to ensure efficient engine and aftertreatment calibration. An up- and downstream measurement of the particle filter provides valuable PN insights for the calculation of the filtration efficiency and parameter optimization. These tests need to be performed under different ambient conditions - low/high temperature and high altitude - in altitude simulation chambers and on altitude testbeds. This is the key to successful RDE tests on the road.

APC Testbed

Versatile PN Emission Measurement

The APC xApp is available in four different configurations and suited to different applications. 
The APC xCert is used for diluted exhaust gas sampling and supports the certification of Euro 6 standards for passenger cars according to UNECE-R83 or heavy-duty engine certification of EURO VI according to UNECE-R49 standards. 
During engine development, you can use the APC xApp family to measure undiluted exhaust gases. It also has R&D applications in anticipation of the EU7 draft specifications with its 10nm PN size limit. 

Technical Data  

Measurement principle

Laser scattering condensation particle counting (CPC)
Measuring components Particle number concentration of solid particle number concentration (#/cm³)
Signal processing Enhanced single peak detection
Ambient altitude conditions    - 30 °C … + 45 °C


Application Flexibility 

Versatile applicability beyond the actual and future RDE ambient conditions for temperature and pressure.

Dual Measurement for 10nm and 23nm

Parallel measurement of 10nm and 23nm provide valuable data for actual and future PN specifications.

ISO 17025 Quality Standard

Calibration of the devices, following the highest quality standards acc. to ISO17025.

Accurate in Extremes of Altitude and Temperature

The xApp stands for multiple and extreme environmental conditions such as an operation range from –30 °C up to 45 °C and RDE altitude specifications up to 3,000 m (700 mbar). 

Available in 4 Versions for Different Applications

  • APC xApp for comprehensive coverage of all for 23 nm measurement tasks with diluted and raw exhaust. 
  • APC xCert for 23 nm measurements with CVS tunnels or partial flow dilution systems (PFDS). 
  • APC xApp 10 for draft EU7 R&D purposes for 10 nm measurements.
  • APC xApp Dual for the PN measurement of 10nm and 23nm in parallel.   

Serviceable Primary Diluter

The primary diluter is a patented “Chopper Diluter” allowing a wide dilution range under fluctuating inlet pressures and temperatures. Based on its compact and innovative design it can be serviced on-site in the R&D application.

SPCplus background
AVL Smart SamplerPLUS

Partial flow dilution system for regulatory particulate matter (PM) measurement of internal combustion- and H2-ICE engines. 


The in-vehicle measurement platform supporting all global Real Driving Emission (RDE) test requirements. It is a single platform for every on-road application worldwide.

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To appropriately manage the test equipment in a test lab or in a test vehicle, is one of the most underrated tasks within the propulsion development process.

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