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A commercially available Portable Emissions Measurement System (PEMS), the SEMTECH-G® (Sensors Inc., Saline, MI), was evaluated under laboratory conditions at a chassis dynamometer test facility at Ford Motor Company's Research and Innovation Center. Cumulative Mass Emissions (CMEs) for carbon monoxide (CO), total hydrocarbons (THC), oxides of nitrogen (NOx), and carbon dioxide (CO2) were measured for three different gasoline powered vehicles. A total of twenty three test cycles were conducted. Results from the conventional laboratory bag analyzer system (Horiba MEXA®7200-TR), the conventional laboratory modal analyzer system (Horiba MEXA® 7100-DEGR), and SEMTECH-G® were compared. CMEs for CO, THC, NOx, and CO2 measured using the SEMTECH-G® were found to be in good agreement (within 10% in all cases) with the results from the conventional modal analyzers.

A commercial PEMS, the SemtechD, was evaluated for its suitability to measure transient emissions from light-duty, oxidation catalyst equipped, diesel passenger cars. The PEMS was evaluated for its analytical capabilities in a state-of-the-art chassis dynamometer test facility. The system, manufactured by Sensors, Inc of Saline, MI, proved to be both accurate and precise. The SemtechD proved capable of measuring THC concentrations (FID-based measurement) as low as 2 ppmC with measurements on average within 4.5% of those reported by modal test cell instrumentation. Similarly, both CO and NOx measurements fell within 9% and 3% of the values reported (respectively) by modal test cell analyzers. Finally, modal CO2 agreed within 2.6% of the two measurement systems across eleven vehicle tests and with more than 6000 data points compared.

A coulometric SO2 monitor has been developed to measure SO2 generated from combustion of S in oil to determine engine oil consumption. Sulfur-free fuel (<2 ppm S) is used to eliminate background levels of SO2. Addition of an SO2 standard gas to the engine during tests insures accurate normalization of sampling system flows and quantitative measurement of engine oil economy. Precision of the SO2 microcoulometer technique was better than ±8%. The SO2 microcoulometer is used during steady state engine operation, and may be used in determining oil consumption from individual cylinders. Existence of engine oil consumption via an aerosol mechanism is investigated and measured. Effects of engine operating temperature and positive crankcase ventilation (PCV) on engine oil economy are given.

An analysis system is described which is composed of a Fourier transform infrared spectrometer, a quadrupole mass spectrometer, a total hydrocarbon analyzer, and a PDP 11/23 microcomputer as a data logger. This analysis system allows on line, simultaneous measurement of a multitude of engine operating parameters, regulated emissions, and non-regulated emissions. The measured engine operating parameters include: air/fuel ratio, exhaust volume flow, hydrogen/carbon ratio of the fuel, and instantaneous fuel economy. Data are presented demonstrating the system’s ability to reveal correlations among engine operating parameters and emissions, for both catalyzed and non-catalyzed exhaust emissions from methanol fueled engines. Data are also given comparing the analysis system with conventional instrumentation. The system provides exhaust composition, engine operating parameter data, and mass per mile emission rates with a 3 second time resolution without the use of a CVS unit.

A fast-response zirconia sensor-based instrument has been developed to measure the air/fuel ratio (A/F) of combustion exhaust. This instrument uses a reduced-pressure sampling system which improves instrument response time (due to faster diffusion at lower pressures) and eliminates the need for a heated sample line. The measured response time of the described instrument is 170 ms (0-90%) for a step-change in O2 concentration. The prototype instrument is easily calibrated in less than 2 min, requiring only nitrogen and room air for calibration. A complete description of the instrument is given. Results of tests comparing the instrument accuracy to a chemical balance technique are given. Also, a comparison study was conducted with the prototype instrument and a conventional zirconia sensor-based A/F monitor (Lamdascan, Sensors, Inc., Ann Arbor, Mich.) with respect to accuracy and response time.

A gas analysis system is described which is composed of a Fourier transform infrared spectrometer, a quadrupole mass spectrometer, and a total hydrocarbon analyzer. This combination of instrumentation along with a unique sampling system allows on-line analysis of regulated and non-regulated emissions. Data are presented demonstrating the system's capability for analysis of regulated and non-regulated emissions from catalyzed and non-calatyzed exhaust. To demonstrate the accuracy of the analysis system, both oxygen and carbon mass balance data are given for an experiment involving the three/way catalysis of a steady-state gas stream synthesized to resemble the exhaust from a gasohol fueled engine. The use of these techniques for the analysis of vehicle emissions is also demonstrated.