Blow by emissions







Blow-by gas has become a large contributor to the total PM emitted by engines as the tailpipe emissions from modern engines have been reduced significantly over the recent years. Blow-by gas is formed in an internal combustion engine when a mixture of gases and oil mist leak from several sources, mainly the combustion chamber. This emitted blow-by gas consists mainly of oil droplets that not only increase the total vehicle PM emissions to the environment but also contribute to the loss of lubricating oil and fouling of surfaces and engine components.

Dekati® Solutions for blow-by gas measurements include:

  • Real-time particle size distribution and concentration 6 nm – 10 µm
  • Sample conditioning and dilution solutions



ELPI®+ is a real-time particle size distribution measurement instrument for both tailpipe and blow-by gas emission measurements from different types of engines. The wide particle size range of 6 nm – 10 µm and fast time response of 10 Hz make the ELPI®+ an excellent choice for real-time determination of PM levels from different conditions. The ELPI®+ features include real-time stand-alone operation, wide sample concentration range, wide particle size range and robust structure for operation even in harsh conditions such as blow by gas measurements. The ELPI®+ can be connected to the particle source either directly using the High Temperature ELPI®+ or with a well designed sample conditioning system such as the Dekati® Diluter.

ELPI®+ features:

  • Real-time particle size distribution and concentration 6 nm – 10 μm
  • 10 Hz sampling rate for detecting small timescale changes in the sample
  • Up to 500 particle size classes with Dekati® High Resolution ELPI®+
  • Independent stand-alone operation or control via laptop using ELPI+VI software
  • Analogue inputs and outputs for data integration
  • Wide operational concentration range suitable for direct blow by gas sampling or sampling via a dilution system
  • High Temperature ELPI®+ for direct sampling of hot sample up to 200 °C
  • Suitable also for tailpipe emission measurements


ELPI®+ setup options for blow-by gas measurements: