Temperature matched the ambient temperature ( C) when the test began. It must be noted that due to a technical difficulty, the PEMS-LAB was not applied during the laboratory test performed at 23 C. VELA7 can be a climatic test cell that comprises a 2-axis roller dynamometer (72″ inches) devoted to heavy-duty vehicle testing. The Polmacoxib cox exhaust gas was connected for the complete dilution tunnel, using a 9 m transferline feeding a complete dilution tunnel with constant volume sampler (CVS). Criteria pollutants NOx, CO, HC and CH4 have been measured employing AVL AMA i60 analyzers (each the raw exhaust and also the dilution tunnel). VELA7 can also be equipped having a laboratory grade FTIR spectrometer (Nicolet Antaris IGS Analyzer–Thermo Electron Scientific Instruments LLC, Madison, WI, USA)–SESAM–that makes it possible for for the measurement of NH3 and N2 O. The SESAM was connected along the OBS-ONE-XL plus the PEMS-LAB to the vehicle’s tailpipe. It makes use of a heated PTFE FAUC 365 MedChemExpress sampling line (191 C). This FTIR was equipped having a multipath gas cell with two m of optical path as well as a downstream sampling pump (6.five L min-1 flowrate), and had the acquisition frequency of 1 Hz using a workingAppl. Sci. 2021, 11,6 ofpressure of 860 hPa. The FTIR was created up using a Michelson interferometer (spectral resolution: 0.5 cm-1 , spectral range: 600500 cm-1 ) and also a liquid-nitrogen-cooled mercury cadmium telluride detector. To be capable to evaluate the OBS-ONE-XL with another method getting an acquisition frequency of ten Hz (see Section three), a laboratory-grade QCL-IR (MEXA-ONE-QL-NX) was also made use of for the duration of two committed tests performed in the VELA7. The MEXA-ONE-QL-NX measures 4 nitrogen compounds (NO, NO2 , N2 O, NH3 ) simultaneously by using a QCL light supply and Infrared Absorption Spectroscopy (IR spectroscopy) as the measuring principle. The analyzer utilizes a high resolution spectrum plus a high vacuum optical cell in an effort to reduce the interference offered by the co-existing gases. In addition, the ammonia response has been enhanced by using a vacuum sample transfer line maintained at a temperature of 113 C. The program consists of three principal components–a Most important Handle Unit, an analyzer unit as well as a heated filter (F-01HN). The F-01HN consists of a quartz filter element specifically developed to decrease the adsorption with the ammonia molecules present within the exhaust gas. The heated filter is connected to the analyzer unit by way of a heated line. The sampling from the exhaust is conducted making use of an insulated stainless steel sampling probe placed in front with the system’s pre-filter, in addition to a 10 m heated line connecting the pre-filter along with the QCL. For the chassis dyno tests performed within this study, the concentrations of N2 O and NH3 measured by the OBS-ONE-XL plus the PEMS-LAB were in comparison to those measured by the laboratory-grade FTIR. The laboratory-grade FTIR (and the QCL-IR in two devoted tests) was chosen because the reference approach because FTIR and QCL-IR are two from the tactics prescribed in the EU Regulation 582/2011 [26] and UNECE GTR-15 [27] to measure NH3 emissions from heavy-duty exhaust and light-duty exhaust, respectively. Furthermore, the UNECE GTR-15 also indicates that N2 O emissions could be measured from light-duty car exhaust using FTIR and QCL-IR, among other procedures (e.g., GC-ECD and NDIR). The regression lines presented inside the study had been fitted to zero. three. Benefits and Discussion The exhaust emissions of N2 O and NH3 from the HD-CNG, an interurban bus meeting the Euro VI Step D common, were measured dur.