Contact Mass Air Flow Measurement System

Increasing demands to the protection of the environment require more and more complex measures to lower the fuel consumption and emissions of internal combustion engines. Even small changes to an engine have to be validated in thorough tests on engine test benches. In this process the accurate measurement of the combustion air mass flow is extremly important. For this purpose FEV has developed the FEV-AirRate, which meets all current demands concerning a state of the art measuring system for combustion air mass flow. The FEV-AirRate measuring principle is based upon contactless measurement of gas velocity, pressure and temperature and provides the actual combustion air mass flow in kg/s.

The ultrasonic gas flow meter with 4 measuring paths enables a high accuracy air mass flow metering over the whole measuring range. The very fast response time of the system assures reproducible test results, even during high dynamic engine test cycles. The low pressure drop of the system does not influence the engine behavior. Due to the wide measuring range, the complete range from single cylinder engines up to heavy duty engines can be covered by only two measuring systems: FEV-AirRate 100 and FEV-AirRate 150.

The FEV-AirRate is easy to install because of the very compact size of the unit. The steadying lenghts at in- and outlet ot the FEV-AirRate are only 5 x the inner diameter.
Due to the integrated flow rectifier, the FEV-AirRate can also be mounted directly behind a pipe bend without increasing the steadying length. FEV-AirRate ist suitable for test cells with or without air conditioning systems.


  • High measuring accuracy due to direct 4-path layout without reflection of signals
  • Bi-directional measurement without pressure loss
  • Fast response time, suitable for high dynamic test cycles
  • Suitable for air mass flow measurement of single cylinder engines
  • Low pressure drop, no influence on engine behavior
  • Wide measuring range up to 1:140
  • No mechanical wear
  • Long-term stability and reliability
  • Low maintenance requirements due to ultrasonic transducers made of titanium
  • Easy to install 


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