Technical Paper
Fast Emissions Analyzers for In-Vehicle and Roadside Measurements
2021-09-05
2021-24-0084
The use of fast response emissions analyzers to correlate spikes of emissions with engine parameters such as lambda and EGR is well known for engine test cell and chassis dynamometer work. However, the adaption of these analyzers for in-vehicle use allows engineers to identify real world situations where significant tailpipe emissions occur over short durations which may not be visible with standard PEMS equipment and to correlate these events with other engine parameters. Sampling raw exhaust gas pre muffler eliminates the extra gas mixing due to these sound deadening devices and allows high fidelity identification of emission breakthroughs during transients. Through such identification, engine calibrators can adjust ECU parameters enabling such transient emissions problems to be cured. Accurate and adequate urea dosing and EGR transients are of particular interest in diesel vehicles.