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A laser mass spectrometer (LAMS) for simultaneous detection of NO, NO2, NH3 and other components (N2O, CO, O2, H2O, aromatics) in the exhaust of combustion engines is presented. Its temporal resolution is in the 10 ms range. Comparison with non-dispersive IR, flame ionisation detection and chemical luminescence detection have been performed. Emissions of Otto and Diesel engines have been studied at different velocities, load and three sampling positions: in front of a catalytic pre-converter, in front and after the main catalytic converter. Finally, NO, CO, H2O, toluene and O2 were detected within the cylinder in dependence on the crank angle with a time resolution in the 10 ms range.

Time-resolved concentrations of formaldehyde and acetaldehyde in the exhaust gas have been investigated during transient motor operation, such as sudden change of speed and load, misfiring and switching off the fuel mixture control. To this purpose, a new laser mass spectrometer has been applied which is capable of measuring the concentrations of individual exhaust compounds with 1 ppm sensitivity at a sampling rate of 50 Hz corresponding to a sampling period of 20 ms. At sudden speed changes, high concentrations of aldehydes are observed, in particular during the phase of decreasing speed, i.e. after closing the throttle valve.

A sensitive laser mass spectrometer is being developed for fast multicomponent engine exhaust analyses. The features of the system meet the requirements of the analysis problems at dynamic motor test stands: detection of all organic and inorganic exhaust constituents of concentrations higher than 1 ppm simultaneous detection of up to 12 selectable exhaust compounds with 100 Hz repetition rate 2 millisecond time precision relative to the motor phase. precise sampling location everywhere in the exhaust pipe system, e.g. single valve or cylinder exhaust gas analysis ruggedness for operation at engine test facilities The time and space resolution allows the tracking of the different exhaust components during one and more motor cycle in static and transient engine operations. This information is essential for an understanding of the combustion processes, which is necessary for the development of the engine and engine control and other efforts to reduce emission of pollutants.

A new analytical method for the automobile industry has been developed using a pulsed tunable laser system and a Reflectron time-of-flight mass spectrometer. The goal was to achieve the following conditions: High time resolution (〈100ms), high sensitivity (down to 1 ppm), high accuracy (10%) and applicability to most exhaust emission components. The main problem is the large number of components with very different and fast varying concentrations. For a preliminary list of 25 exhaust emission components, all necessary parameters have been determined. First results obtained from a real exhaust gas sample will be presented.