Air Consumption Measurement Device


The AVL FLOWSONIX™ Air determines the intake air mass flow with high accuracy, large turndown ratio and fast response time.

AVL Approach

Along with the fuel consumption, the air consumption is another important parameter when developing combustion engines. In emission certification, the air consumption is taken as reference value. Thus, the air consumption is an integral part of AVL testbed solutions.

The AVL FLOWSONIX™ Air consists of the components of measuring head, evaluation unit and two very short inlet- and outlet pipes (<5* DN each). Due to the large measuring span of 1:70, only two different pipe diameters are needed (DN 100, DN 150) to cover the full application range of up to ± 2,600 kg/h.

Benefits at a Glance

  • The unique AVL FLOWSONIX™ Air is not sensitive to contamination, which enables long maintenance intervals
  • Marginal influence on the combustion engine due to small pressure drop in the measurement head
  • Quick and easy installation for any engine type
  • High availability of the measurement device due to extended calibration interval of one year
  • One size fits all. Due to the wide measurement range only 2 different instrument versions are required:
    Light Duty or Heavy Duty
  • Little space required - just < 5 × DN up-stream and down-stream tubing

Technical Data

Measurement principle

Ultrasonic transit time

Measurement ranges

0 (± 20) … ± 1,400 kg/h (LD Version)

0 (± 40) … ± 2,600 kg/h (HD Version)

Response time

T90 = < 10 ms


± 0,25 % of reading

Measurement uncertainty

< ± 1 % of reading

Temperature of air

- 20 … + 80 °C

Operating pressure max.

250 kPa abs.

Pressure drop of Measuring Head

0.25 kPa

Ambient temperature of Measuring Head

- 20 … + 60 °C

Ambient temperature of the Evolution Unit

- 20 … + 60 °C


AK interface Ethernet (TCP/IP)

AK Interface RS232

CAN Bus Interface

Analog 0 … 10 V, 4 … 20 mA

Digital I/O

Power consumption

25 W

Power supply

110 / 230 VAC ± 15 %

50 / 60 Hz ± 5 %

Normal size DN

LD Version 100 mm

HD Version 150 mm

Measuring Principle


The measuring principle is based on the ultrasonic transit-time differential method. Two ultrasonic pulses are sent simultaneously through the flowing medium from Transmitter 1 (T1) and Transmitter 2 (T2). One pulse is propagating into the flow and the other one against it. The interaction between the speed of sound c and the velocity of flow v accelerates the pulse on one of the paths and decelerates the pulse on the other path. This effective propagation velocity results in different transit times through the medium: The signal at Receiver 1 (R1) arrives faster than the signal arriving at Receiver 2 (R2). The device measures the speed of sound traveling either way, corresponding to t1 and t2.