Typical uses of fast NDIR system

The Cambustion NDIR500 fast CO&CO2 analyzer has a T10-90% response time of 8 milliseconds which allows for measurement of very fast transient exhaust or intake gas.  The robust sampling system can be configured to cope with positive or negative fluctuating pressures which provides stable EGR measurement without pressure interference during transient turbocharged or throttled operation.  This yields significant additional information about transient EGR delivery compared with conventional EGR measurement which tends to be one of the slower components to be measured in a standard bench analyzer.

Fast measurements of CO2 in the engine inlet

The ability to measure cycle-by-cycle exhaust port CO&CO2 can provide fast fuel : air ratio information for burning cycles during cold start which aids transient fuelling calibration and generally, the measurement of transient exhaust gas streams (both pre- and post catalyst) can provide after-treatment dynamic information which is otherwise obscured by slow response instruments.


The NDIR500 is frequently used to calibrate and develop Exhaust Gas Recirculation (EGR) systems for NOx control. Through measurement of the CO2 concentrations in the exhaust, and at various points through the EGR system, the system behavior can be measured and models verified.

The NDIR500 can make measurements of the CO2 concentration in pre-combustion gas sampled from the cylinder. This allows the total residual gas fraction to be measured (i.e. internal and external EGR) and is particularly useful in revealing features such as poor EGR distribution on multi-cylinder engines, or the effects of variable valve timing on trapped residuals.

During cold start of a spark ignition engine, significant fuel puddling can occur in both port- and direct-injection engine types. This fuel is not available for combustion at the spark, and subsequently exits the cylinder through the exhaust valve. The situation may arise where combustion is lean (low availability of vaporized fuel at spark) but the engine out hydrocarbon concentration is very high.

This high HC concentration can cause sensors such as UEGOs to incorrectly indicate the AFR. By simultaneously measuring the CO & CO2 concentration in the burnt gas, the NDIR500 can be used to calculate the AFR (or lambda) for the gas which took part in combustion. This calculation can be performed for each firing cycle during and after engine start. Such data is particularly useful when looking at GDI engine start (where the time available for vaporization is less) or when using alternative fuels such as ethanol, which vaporizes less readily.

The NDIR500 is available with support for AK protocol, allowing easy integration with the test bench for improved test reliability and reduced workload.

To read more on fast gas analyzer applications such as residuals measurement, AFR calculation etc please visit our page on Spark Ignition Engines.

See Applications and sample data for more information on these and other applications.

Download a brochure.

Contact Cambustion for more information and prices.

Key Application Notes 
Title Data type Download File Size Last updated
Flame Traverse Sampling Application note PDF icon CLD06v01 Fast gas analysis traversing a methane flame.pdf 607.88 KB 22-Sep-2015
Measurement of burned gas back-flow in the intake port Application note PDF icon NDIR01v02 Spit-back.pdf 370.83 KB 24-Feb-2015
Fast response CO and CO2 sampling of a diesel engine Application note PDF icon NDIR02v02 Diesel Sampling.pdf 465.43 KB 24-Feb-2015
Cycle-by-cycle AFR measurement of a cold start using an NDIR500 and HFR500 Application note PDF icon NDIR03v02 AFR measurement.pdf 442.5 KB 24-Feb-2015
Fast Analysis of Fluidised-Bed Combustion Application note PDF icon NDIR04v02 fluidised bed.pdf 133.69 KB 24-Feb-2015
Measurement of EGR delay and its effects on NOx emissions using the NDIR500 and CLD500 Application note PDF icon NDIR05v02 EGR delay.pdf 117.45 KB 24-Feb-2015
Observing EGR valve leakage using the NDIR500 Application note PDF icon NDIR06v02 EGR valve leakage.pdf 188.92 KB 24-Feb-2015
Using the NDIR500 in a turbo-charged exhaust Application note PDF icon NDIR08v01 turbo-charged exhaust.pdf 89.97 KB 24-Feb-2015
GDI blow-through during scavenging at high load PDF icon NDIR09v01 GDI blow through.pdf 214.37 KB 02-Feb-2015
Mobile CO&CO2 measurement on-board a gasoline vehicle PDF icon NDIR10v01 Mobile CO&CO2 gasoline.pdf 275.97 KB 14-May-2015
Mobile CO&CO2 measurement on-board a diesel vehicle PDF icon NDIR11v01 Mobile CO&CO2 diesel.pdf 450.64 KB 14-May-2015