AVL Opacimeter

The AVL Opacimeter is a highly dynamic partial-flow measuring instrument for continuous measurement of exhaust gas opacity. It is used in particular for R&D, certification purposes and to ensure production conformity.

AVL Approach

As a partial-flow system for online measurement of exhaust gas opacity in diesel engines, the AVL Opacimeter complies with a number of existing legal requirements such as ECE R24 or the ELR test cycle.

Its high accuracy, excellent dynamic, outstanding reliability and the user-friendly design combined with the ability to use the device upstream and downstream of a DPF (diesel particulate filter) make the AVL Opacimeter a unique product.

Technical Data


Measuring value output Opacity N [%] or absorption k [m-1]
Measuring range N = 0 ... 100% or k = 0 ... 10 m-1
Resolution of displayed measuring values 0.01 % opacity or 0.001 m-1
Limit of detection 0.02 % opacity or 0.0025 m-1
Zero stability {0.1 % or 0.0025 m-1}/30 min.
(drift with zero gas)
Rise time 0.1 s
Data transmission speed 50 Hz with analog output
1 ... 10 Hz with RS 232 serial interfaces
Ambient temperature +5 °C … +50 °C
Exhaust gas temperature 0 ... 600 °C (800°C with high pressure option)
Exhaust gas pressure -100 mbar ... + 400 mbar
(including pulsation peaks)
0 mbar ... +3000 mbar with high pressure
option (including pulsation peaks)
Dimensions basic unit 680 x 440 x 460 mm (W x H x D)
Weight basic unit Approx. 47 kg



Measuring Principle

AVL Opacimeter
The AVL Opacimeter measures the opacity of contaminated air in particular of diesel exhaust emissions.
A measuring chamber of a defined measuring length and non-reflective surface is filled homogeneously with exhaust gas.

The light attenuation caused by the exhaust gas particles trapped between a light source and a receiver (“opacity” in %) is measured. The specific absorption of the exhaust gas (“k”, in m-1) is calculated based on the opacity. The calculation is based on the Beer-Lambert law.