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Technical Paper

In-Vehicle Engine Coolant Void Fraction and De-aeration Monitoring Using a Computerized Electrical Conductivity Method

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.
Technical Paper

A Sampling System for the Measurement of PreCatalyst Emissions from Vehicles Operating Under Transient Conditions

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.
Technical Paper

Near Infrared Absorption Sensor for In-Vehicle Determination of Automotive Fuel Composition

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.
Technical Paper

An Advanced Instrument for the Real Time Measurement of Engine Oil Economy

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.