No abstract

In this work, an in situ multispecies portable emission measurement system (PEMS) is presented. The system is based on tunable diode laser absorption spectroscopy (TDLAS) and is capable of measuring tailpipe emissions without the necessity of online calibration. It is intended for application on passenger cars within the real drive emission (RDE) procedure of the Worldwide Harmonized Light Duty Test Procedure (WLTP).In contrast to the extractive measurement principles of commercially available PEMS, the introduced measurement system does not require gas sampling or preconditioning and thus does not su er from the same low-pass fi lter e ects on the measurements. These di erences are suspected to have an impact on certifi cation-relevant measurement data. Measurements have been conducted on a 3-cylinder 1 liter EURO 6b gasoline engine test bench to investigate the di erences between the presented measurement system and a commercially available PEMS.For the WLTP relevant investigation, water (H 2 O), carbon dioxide (CO 2 ), carbon monoxide (CO), nitrogen oxide (NO), ammonia (NH 3 ), and methane (CH 4 ) were detected with an e ective temporal resolution of 10 Hz by the introduced PEMS. The comparison of CO and NO concentration curves between the two systems show a distinct low-pass fi lter behavior of the commercially available PEMS. It is shown that the low-pass fi lter infl uences the calculation of the certifi cation-relevant cumulative emissions, leading to deviations between both systems. As a result, deviations of up to 12% (CO) and 17% (NO) have been measured within the fi rst 800 s of the Worldwide Harmonized Light Duty Test Cycle (WLTC). Increasing vehicle dynamics (e.g., in RDE application) are expected to lead to even higher deviations.

No abstract

The fulfillment of quality and regulation requirements for thermo-chemical industrial processes rely on new measurement technologies based on laser-optical methods. Here we present a robust multi-channel, multi species measurements system for the quantification of exhaust gas species direct at the tail pipe end of a driving car. The application of the TDLAS-spectrometer as well as results of a syn-fuel test drive are presented and discussed in detail regarding optical system robustness and uncertainties.