A comprehensive evaluation method for instantaneous emission measurements

he effects of variable gas transport times are well known to be a challenge for generating high quality test results from emission measurements. This is especially valid for correct allocation of modal emission mass signals to the operating points of internal combustion engine and exhaust aftertreatment
system. These time shift effects occur both at test benches and at portable emission measurement systems.
At the ICE(Institute for Internal Combustion Engines and Thermodynamics) of the TU Graz (University of Technology Graz) an algorithm was developed, which allows for consideration of variable gas transport times based on measured exhaust mass flow and volumes and temperatures in the measurement system. This algorithm was implemented into the software “ERMES tool” which is capable to perform evaluations of measurement data from any kind of emission test systems (diluted from CVS, undiluted from engine dyno or PEMS measurement). The tool now provides methods to
correct emission test results for effects of analyser response behaviour and transport times in diluted and undiluted parts of the measurement equipment.