Skip to main content

Blow-by separator testing

Oil-bearing blow-by gas from the crankcase is one of the factors that significantly influence the emission behaviour of vehicles (EURO standard). Excessive oil loss also damages the engine. Since the separation efficiency of oil mist separators depends on the operating point of the engine, this results in a correspondingly complex characteristic map. The established gravimetric approach to characterizing oil mist emissions provides only a very low resolution of this map due the long measurement times necessary. Consequently, this leads to high costs for the use of engine test benches.

With the robust optical inline measurement technology developed by Topas, complete maps of crankcase emissions can be measured in less than one day with significantly improved resolution by cleverly combining the optical inline measurement with an application-optimized gravimetric approach.


Meet the high requirements of oil mist separators with an optimum solution using our blow-by-separator test system

With the selection of a suitable separator for a particular engine, your goal is to minimize the blow-by oil content and thus to reduce emissions and protect many essential parts of the crankcase and engine. As a manufacturer of oil mist separators, or as an engine or passenger car manufacturer, you know that while engine development is stagnating, at least in the passenger car sector, exhaust emission standards are becoming more stringent. This is why a high degree of separation is demanded of oil mist separators today, which can often only be achieved with active separators. Our test systems make valid statements about the content in crankcase gases. This means that separators can be selected and optimized to suit the application. Our technology also contributes to the improvement of all filters in the engine air stream (intake, blow-by and exhaust filters).


We confirm the quality of your products.

Testing under laboratory conditions with the SPT 140 oil mist separator test system

The SPT 140 is used to validate oil mist separators in the laboratory under simulated operating conditions prior to installation. To do this, the SPT 140 simulates the engine as a reference system and enables the following test procedures:

  • Total separation efficiency (gravimetric)
  • Flow curve (pressure drop versus volume flow)
  • Pressure control curve
  • Leakage volume flow
  • Oil mass flow rate (g/h)
  • Oil concentration (g/m³)

The LDG 244 oil droplet generator for large oil droplets is implemented in the test system to simulate wall film and surge oil effects. The core of the test rig is the ATM 243 aerosol generator, which was specifically developed for testing oil mist separators.




Three innovative Topas technologies combined in one measuring system

Testing on the engine test bench with the BBT 143 blow-by test system

The BBT 143 transportable measuring system is used to validate oil mist separators directly on the running engine under realistic conditions. The test method records the oil mass flow and can be fully integrated into the engine test bench in terms of control and measurement data acquisition. The following evaluations can be performed:

  • Determination of the oil content in the blow-by on the engine test bench
  • Blow-by volume flow measurement (l/min)
  • Oil mass flow determination (g/h)
  • Oil concentration (g/m³)
  • Evaluation of oil mist separators on the engine test bench
  • In-line detection of wall films and surge oil
Good to know

We are going with the trend!

  • Our blow-by test stand BBT 143 is the result of a joint project with a world-leading automotive manufacturer and a global filter manufacturer. It is now in use at almost all major international automotive and oil mist separator manufacturers.
  • For fractional efficiency measurement in the laboratory and on the engine test bench, the FMS 375 fractional efficiency measuring system can be used as an accessory and provides valuable additional information on the particle size-specific separation efficiency of the test specimen.

Our technical solution

ATM 243

Atomizer Aerosol Generator ATM 243 for aerosol generation from liquids, compressed air operated, heatable, ideal for motor oils and oil mist separator testing

Atomizer Aerosol Generator ATM 243, front view
detail view

BBT 143

BBT 143 test system for the characterisation of the oil content in blow-by gases at engine test systems

Blow-By Test System BBT 143, front view
detail view

GMS 141

GMS 141 gravimetric sampling system of oil concentrations at Blow-By oil mist separators

Gravimetric Measurement System GMS 141, front view
detail view

LDG 244

Large Droplet Generator LDG 244 for coarse droplet generation from liquids, best for wand film formation from motor oils

Large Droplet Generator LDG 244, front view
detail view

PAP 610

Process Aerosol Photometer PAP 610 for analysis of particle mass concentration in aerosols, best for oil mist characterisation during blow by testing

Process Aerosol Photometer PAP 610, front view
detail view

PAP 612

Process Aerosol Photometer PAP 612 for analysis of particle concentration in aerosols, extinction/scattering light for twi wavelength, best for blow by testing

Process Aerosol Photometer PAP 612, front view
detail view

SPT 140

Test System SPT for testing of separator, especially for blow-by oil mist separators

Oil Mist Separator Test System SPT 140, front view
detail view