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Using actual parts from a typical jet engine, a test rig was designed and constructed. Operating under typical jet engine conditions, the rig was capable of differentiating between oils on the basis of seal deposits and used oil data. The possibility also existed that differences in carbon seal wear rate could be determined. Final correlation of the results with field information will determine if the differences noted are significant.

The high temperature permanent and temporary viscosities of oils run in a diesel injector shear stability test were compared with similar data for two European laboratory engine tests. Low shear rate permanent viscosity losses for oils run in selected European cars were compared with laboratory data. Shear stability as commonly determined by the diesel injector test and low shear rate viscosity measurements does not permit adequate assessment of the shear stability of engine oils. The viscosities measured at high shear rates and high temperatures appear to provide a more useful dimension in the characterization of oils than do standard viscosity measurements. Temporary viscosity losses tend to be larger than permanent viscosity losses.

Piston ring wear studies using an automotive engine and a radioactive wear measurement technique are presented to show the effects of compression ring face metallurgy and general lubricant composition on corrosive wear control. These results are correlated with those obtained in a single-cylinder laboratory engine. Results show that lubricant com-position is not critical respecting corrosion when chromium plated and molybdenum-filled compression rings are used, but is critical when plain cast iron rings are used. Although wear for the molybdenum rings may be slightly higher than that for chromium rings, no service problems are anticipated.

Studies of several options available for future vehicular transportation powerplants have strongly indicated that it is necessary to optimize the vehicle, its fuel, and the refinery as a total system. It is the purpose of this paper to report the relative miles of transportation that can be obtained from a barrel of crude oil by using different types of engines and fuels. This concept is not new. The energy required to manufacture fuels has always been supplied by using part of the energy in the crude oil. However, the importance of the concept is compounded when one considers that large quantities of gasoline are lost due to processing requirements for producing unleaded gasoline octane numbers while concurrently, automotive emission controls and safety regulations increase gasoline consumption. Both of these effects cause a reduced efficiency in the use of crude oil.

High boiling point components of gasoline have been shown to have an adverse effect on engine-out hydrocarbon emissions for port fuel injected (PFI) engines. Fuel charge inhomogeneity and wall wetting contributes to the abnormally high hydrocarbon emissions associated with cold and warm engine starting. In this work, a series of aldehydes with varying molecular weight and boiling points were used as fluorescent tracers to study the effect of fuel volatility and engine operating conditions on the in-cylinder charge distribution. The tests were conducted in an optically accessible engine consisting of a production GM Quad-4 cylinder head and intake manifold, with an FEV systemmotor crankcase and “Bowditch” transparent piston. Planar laser induced fluorescence was used to study the in-cylinder fuel vapor distribution and to determine the presence of liquid droplets.

This study investigated the relationship between the average molecular structures of combustion chamber deposits (CCD), the quantity of deposit formed and the aromatic content of the fuel. Solid-state 13C nuclear magnetic resonance (NMR) techniques developed for the study of coal were applied to CCDs generated in spark ignition engines on dynamometer test stands. Using these techniques, the molecular structures were identified and related to fuel chemistry, cylinder deposit thickness and cylinder deposit weight. With a better understanding of the structure of the deposits formed during combustion, fuel formulations and CCD control-additive development can be greatly improved.

Planar laser induced fluorescence (PLIF) imaging of hydroxyl (OH) radicals is applied to a single cylinder spark ignited internal combustion engine (ICE) to study the development of turbulent flames. A single laser pulse from an excimer laser is formed into a two-dimensional (2-D) light sheet which intersects the flame in the combustion chamber at different delay times after the spark ignition, and 1 mm below the spark plug. The PLIF images are then captured with an intensified charge coupled device (CCD) camera, which is time gated with the laser pulse. The single-laser pulse PLIF images are then stored with a video cassette recorder (VCR) for further analysis. Real-time PLIF images were observed at different delay times after the spark ignition from consecutive engine cycles and at different engine speeds running on propane. Cycle-to-cycle variations were observed.

Technological advances in fast multi-element detectors now permit single-shot temporally and spatially resolved chemiluminescence spectra to be observed from an optically accessible four-stroke single cylinder spark-ignition engine. We demonstrate three techniques using multi-element detectors. First, with a wavelength coverage of 300 - 700 nm, we have observed the chemiluminescence spectra from individual combustion events with a time-gated intensified linear photodiode array. The broad wavelength coverage allows discrete spectral peaks of multiple species (OH, CH, C2, CN, NH) to be observed simultaneously and be distinguished from the continuum luminosity of the spectra. Second, by using a digital streak camera equipped with UV optics, the continuous time evolution of the chemiluminescence spectra was obtained from the spark gap of the engine. The temporal evolution of the plasma spectra from the spark-gap region was observed on short time scales (nanoseconds through microseconds).

In this investigation, recently developed techniques to locate knock origins were applied to study fuel and deposit effects as they interact with charge motion. Particularly, the individual and interactive effects of swirl, fuel composition, localized heating, and deposits on in-cylinder knock origin were studied. A Waukesha Split Head CFR engine was modified to accept four pressure transducers for calculating by triangulation the cycle resolved in-cylinder origin of engine knock. Location of the origin of knock within the combustion chamber was based on the difference in time for each pressure transducer to register the onset of knock during the combustion cycle. Computer software was developed and optimized to maximize the success rate in locating knock within 1 cm. In order to explore the difference in location of knock due to fluid dynamics within the cylinder, the shrouded intake valve of the engine was modified to create different swirl conditions within the combustion chamber.

The influence of lubricant formulation and service degradation on automatic transmission shift quality was studied in full scale transmission cycling tests. Fluid frictional degradation was found to follow a well defined pattern. This pattern is influenced by fluid formulation as well as transmission environment. Both fluid oxidation and selective additive degradation affect the rate of progression through this pattern.

Both NOx and particulate emissions are affected by combustion temperatures, although in opposite directions. Combustion temperature, in turn, is related to injection timing. Thus, in general, NOx emissions increase and particulate emissions decrease when injection timing is advanced. For a realistic comparison of diesel fuel quality effects on emissions, therefore, injection timing is important. In this study, fuels of different ignition qualities, but with the same aromatics content, were tested such that a phase of combustion of all fuels was made to occur at the same point in the engine cycle. Under this method, injection timing was optimized for each test fuel such that Peak Rate of Pressure Rise was made to occur at 4.5 degrees after top dead center (ATDC). Testing fuels of different ignition qualities and the same aromatic content under these conditions showed that NOx emissions of high cetane number fuels were significantly lower than emissions of a low cetane number fuel.

Nitrogen compounds present in mineral base oils at low concentrations are known to accelerate oil oxidation and to reduce the useful lifetime of formulated lubricants. Both Partial Least Squares and Neural Network analyses were employed to establish correlations between base oil composition and performance in industry standard thermal stability and oxidation tests. These correlations show that the “basic nitrogen” (BN) content of a base oil is a very important compositional feature determining its ultimate performance in a formulated lubricant which may be especially important for API Group II and III base oils that are relatively free of other pro-oxidants and naturally occurring, sulfur-containing antioxidants. The effect of BN species was also studied using model nitrogen compounds and it was confirmed that the pro-oxidant effect appears only in “basic” nitrogen containing molecules involving pyridine and quinoline derivatives.

The Texaco Ignition System (TTIS) is a high frequency system with a bi-directional spark current, the duration of which is a function of crankshaft rotation rather than time. The spark current characteristics differ drastically from those of conventional discharge systems and, as a result, current flow through the plug gap can be maintained under extremely turbulent conditions. Being essentially a constant current device, it prevents excessive plug current flow during initial gap ionization, providing a good plug life; yet it has high average current to increase fuel ignition probability. The system, developed primarily for use with stratified charge engines, has also been shown to have characteristics which improve the performance of premixed charge engines operated under severe conditions, in order to reduce exhaust emissions, improve driveability and increase fuel economy.

Four pressure transducers were installed into a split-head CFR engine to determine the spatial and temporal location of engine knock. The CFR engine was operated for these experiments using a primary reference fuel of 80% iso-octane and 20% n-heptane (octane number of 80). The compression ratio was varied to obtain different intensities of knock in the acquired data sets. Pressure transducer signals were recorded using a high speed data acquisition system and the resulting traces were analyzed to find where knock was occurring within the combustion chamber. A two dimensional triangulation scheme was developed to locate the knock origin based on the time difference between the acoustic signals detected by the pressure transducers. Limitations in spatial resolution due to digital sampling rate and variations in the speed of sound are discussed.