The optimization of combustion processes and exhaust gas aftertreatment of modern combustion engines becomes more and more important. The highest potential of improvement can be achieved during dynamic engine behavior and cold start conditions. The analysis of exhaust gas composition during these engine conditions with a high time resolution is therefore a necessity and an important tool in engine development.
Measurement systems for this task have to meet many challenges resulting from a very complex gas mixture, rapidly changing temperature and pressure conditions as well as particulate matter at the sampling position in the exhaust pipe. MS and FTIR are often used in engine exhaust gas analysis, but each system on its own has some disadvantages regarding measurable gas components, time resolution, calibration effort and long term system stability respectively.
A hybrid spectrometer system, called IRMA, combines FTIR and EI-MS using real-time data fusion of status and measurement signals of both analyzers. Continuous monitoring of status signals, such as temperature and pressure, allow to compensate for some influences on concentration measurements. The real-time comparison of concentration measurements of both analyzers yield information about the system sensitivity or base line drift and can be used to significantly reduce the calibration effort for the MS.
Different applications of the IRMA system at engine test stands demonstrate some possibilities and advantages of the data fusion. Influences of pressure and temperature variations at the sample position on concentration measurements can be compensated. For some exhaust gas components the parallel measurement supersedes the need to calibrate the MS and results in a maximum time resolution. Understanding of complex development tasks involving many different gas components (e.g. catalytic converters) can be advanced by simultaneous measurement of many different concentrations.
Project Executing Organisation: Bundesministerium für Wirtschaft und Industrie (BMWI)
Term: Jan. 2007 - July 2010
