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In a continuing effort to include real-world emissions in regulatory testing, the USEPA has included air conditioning operation as part of the Supplemental Federal Test Procedure (SFTP). Known as the SC03, these tests require automobile manufacturers to construct and maintain expensive environmental chambers. However, the regulations make allowances for a simulation test, if one can be shown to demonstrate correlation with the SFTP results. We present the results from an experiment on a 1998 Ford sedan, which simulates the heat load of a full environmental chamber. Moreover, the test procedure is simpler and more cost effective. The process essentially involves heating the condenser of the air conditioning system by using the heat of the engine, rather than heating the entire vehicle. The results indicate that if the head pressure is used as a feedback signal to the radiator fan, the load generated by a full environmental chamber can be duplicated.

Instruments and analytical techniques are described for in-vehicle monitoring of amounts of air (void fraction) in engine coolant systems and for evaluating the performance of degas reservoirs. This method, based on electrical conductivity measurements of flowing air / coolant mixture, provides measurement, acquisition and display of coolant system temperature, pressure, flow rate, instantaneous void fraction and rate of air removal by degas bottle. Embedded temperature compensation equations are used for essentially real time display of the void fraction.

A proportional sampler for vehicle feedgas and tailpipe emissions has been developed that extracts a small, constant fraction of the total exhaust flow during rapid transient changes in engine speed. Heated sampling lines are used to extract samples either before or after the catalytic converter. Instantaneous exhaust mass flow is measured by subtracting the CVS dilution air volume from the total CVS volume. This parameter is used to maintain a constant dilution ratio and proportional sample. The exhaust sample is diluted with high-purity air or nitrogen and is delivered into Tedlar sample bags. These transient test cycle weighted feedgas samples can be collected for subsequent analysis of hydrocarbons and oxygenated hydrocarbon species. This “mini-diluter” offers significant advantages over the conventional CVS system. The concentration of the samples are higher than those collected from the current CVS system because the dilution ratio can be optimized depending on the fuel.

A number of advancements have been made in the coulometric sulfur trace instrumental technique for the real-time measurement of engine oil economy. These advancements include modification of the coulometric cell to improve reliability and reproducibility. The instrument has been interfaced with a microcomputer for instrument control as well as data acquisition, storage, and analysis. Studies were undertaken which demonstrate sufficient sensitivity and linearity for determination of engine oil economy at levels better than 10,000 miles/quart. Applications to steady-state engine oil consumption mapping and to instantaneous oil consumption during transient engine cycling are described. These instruments are being produced by an outside supplier for use in various company locations in both the engine production and engine research environments.

The use of methanol as an automotive fuel can be expected to become significant in North America during the 1990's. Methanol fuel will be sold as 85%/15% MeOH/gasoline mixture. Limited availability of methanol fuel in some parts of North America will require methanol vehicles to be dynamically adaptable to fuel compositions ranging from 85% methanol to 100% gasoline. One approach to meeting such a requirement is a sensor that is mounted somewhere in the vehicle's fuel handling system that determines the concentration of methanol in the fuel flowing to the engine. The output of the sensor is supplied to the computer controlled engine management system that sets engine operating parameters. A sensor based on near infrared absorbance is the subject of this paper.

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.