Measuring success

Fast and bidirectional measurement of air mass flow


AVL FLOWSONIX™ Air is the innovative measurement system for the measurement of air consumption that is fast, accurate and robust. 
The measurement system uses an ultrasonic transit-time differential technique to accurately measure air mass flow in the intake. It measures the acceleration of the sound pulse travelling with the air flow, as well as the deceleration of the sound pulse travelling against the airflow. By comparing the two results, the mass of air flowing through the intake can be accurately assessed, delivering measurement uncertainty of less than 1 % of the reading. 

Air consumption is an important reference value in emissions certification; hence OEMs must ensure an accurate measurement process to meet increasingly stringent regulations.
AVL FLOWSONIX Air features highly dynamic and precise bidirectional air flow measurement with a data rate up to 1 kHz. These unique capabilities enable AVL FLOWSONIX Air to measure highly dynamic engine behavior and even flow pulsations in the engine intake path can be resolved and measured bidirectionally. Thus, correct measurement of applications with possible reverse flows are guaranteed. 

Flowsonix Testbed

AVL FLOWSONIX™ Air – The industry standard in intake air measurement

AVL FLOWSONIX Air measures intake air mass flow with high accuracy, a large downturn ratio and fast response time. It consists of the components measuring head, evaluation unit and short inlet and outlet pipes. These are designed to have as little influence on the engine as possible. Only a small pressure drop occurs in the measurement system, which results in a negligible influence on the engine.
Its flexible design allows for a quick and easy installation on any engine type. With a wide measurement range of 1:70 only two pipe diameters are required to cover light duty and heavy-duty applications. 

Technical Data Unit

Measurement ranges 

0 (± 20) … 1,400 (LD version) kg/h
0 (± 40) … 2,600 (HD version) kg/h
0 (± 40) … 3,000 (HD version) kg/h

Measurement uncertainty < ± 1 % of reading
Reproducibility 0,25 % of reading
Temperature air – 20 … + 80 °C non-condensing air
Humidity Max. 85 % relative humidity
Operating pressure max 60 kPa … 160 kPa


Unique Sensor Technology

AVL ultrasonic transducers offer a powerful and constant signal quality with a unique time resolution of more than 1 kHz 20W

Long-Term Stability 

AVL FLOWSONIX offers a proven long-term stable calibration and enlarged maintenance intervals thanks to its robustness and insensitivity against contamination 

Local Calibration Services

Significant reduction of test bed downtime during recalibrations by AVL approved local calibration laboratories directly at your doorstep 

Only 2 Sizes for All Applications

Application independence thanks to the large measuring span and the associated advantage of only 2 measuring tube sizes 

Negligible Influence on Application

Marginal influence on the combustion engine thanks to optimized mechanical design resulting in minimized pressure drop through the measuring system 

Ease of Use

Optimized space requirement supported by smart mechanical design resulting in maximum 5D length of inlet and outlet tubing 

One Device for All Applications

Thanks to the design of the AVL FLOWSONIX Air, it is possible to cover a wide range of applications. From R&D testbeds to endurance testbeds, dilution air measurement, turbocharger characterization and even Break Emission with only 2 measuring tube sizes. 

Direct Output of Mass Flow

AVL FLOWSONIX Air offers the opportunity of direct output of the mass flow rate. A conversion of the also available (standard) volume flow is not necessary and reduces the errors in the data post-processing enormously.

No Influence on Unit Under Test

The mechanical design of the AVL FLOWSONIX Air is focused on providing the highest quality measurement results with the lowest pressure drop. This very low pressure drop allows measurement without noticeably affecting the test unit.

Deep Insight View into Engine Behavior

The ability of AVL FLOWSONIX Air to perform flow measurement with a high time resolution of 1 kHz, even bi-directionally, provides deep insight into engine behavior even in highly pulsating flow conditions.


Fast and bidirectional measurement of intake air mass flow.


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