The AVL BLOW BY METER measures the leaked gas that builds up between the gaps around pistons, piston rings and valve guides. These gases enter the crankcase and leak via the crankcase ventilation system. The volume of blow by gas has proven to be a sensitive indicator of the state of the piston rings, pistons, and cylinder walls. It is a valuable tool in both engines under development and engines out of production and already in use.
The need for continuous measurement of the blow by flow to monitor the engine condition makes the AVL BLOW BY METER an indispensable instrument for engine testing.

The AVL BLOW BY METER 442H has been designed specifically for safe operation in testing environments with potentially explosive gas mixtures within media-carrying components. The device delivers reliable performance, even when the H2 concentration in the blow by gas exceeds the lower explosive limit. Furthermore, the whole setup has been optimized to meet the requirements of the directive for explosion prevention. In addition, the instrument can also be used on conventional engines powered by diesel, gasoline, or CNG.
The AVL BLOW BY METER 442S is used for continuous measurement and monitoring of blow by gases that escape via gaps around the pistons, piston rings, and valve guides (as well as from the bearing and bearing gaskets in turbo charged engines) in conventional engines powered by diesel, gasoline, or CNG only. This innovative and flexible device has the widest measurement range on the market and fits seamlessly into various engine applications.
The user interface is fully embedded into our PUMA automation system and delivers intuitive operation along with quick and easy parametrization. Our blow by meters also impress with a rapid testbed setup and easy integration into any automation system via a CAN bus, analog, or Ethernet interface.
Technical Data | Unit |
Measurement range |
442S: 0.2 … 2,400 l/min (with different sensors) |
Measurement uncertainty |
<= 1.5 % FSO |
Maximum permissible temperature of blow by gas |
80°C |
Operating altitude | Up to 3,000 m |
MASTER THE LEAK – next level blow by measurement.
High Accuracy
The accuracy of 1.0 % FSO with fine linearization (standard 1.5 % FSO) complies with the stringent legislative requirements.
Safe Operation
Safe and accurate steady-state, transient, and dynamic blow by measurement even with elevated H2 concentrations in the blow by gas with AVL BLOW BY METER 442H.
Flexibility in daily operation
AVL BLOW BY METER is the perfect solution for your measurement task in conventional engines as well as H2 ICE and CNG engines.
Outstanding Data Quality
Exceptional data quality thanks to outstanding data rate of up to 500 Hz and state-of-the-art interfaces and interface performance.
Reduced Setup Time
Rapid testbed setup and easy integration into any automation system via a CAN bus, analog, or Ethernet interface.
Easy Operation and Parametrization
The AVL Device Center software with uniform design allows the measuring device to be operated and parameterized with ease.
Setup Compliant with Operation in H2 ICE
The AVL BLOW BY METER 442H meets the requirements of the directive for explosion prevention and has been designed specifically for safe operation in testing environments with potentially explosive gas mixtures within media-carrying components.
Temperature Compensation
If the media temperature differs sharply from the calibration requirements, the recommendation is to use temperature compensation. Standardized adapters with temperature measurement are available for this purpose. After installation, the measuring system performs the compensation automatically.
Pressure Compensation
To compensate significant pressure deviations between media pressure and ambient pressure it is possible to use an absolute pressure sensor for compensation. The measuring system compensates the deviation automatically.
Standardized Solution for Condensate Separation
With the standardized condensate separator for AVL BLOW BY METERs, a solution can be offered that reduces maintenance effort while also increasing the stability of the measurement results.
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