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A 1.8L turbocharged diesel engine valvetrain friction was investigated, and the effectiveness of using a solid film lubricant (SFL) coating in reducing friction was determined throughout the operable speed range. This valvetrain design features direct acting mechanical bucket valve lifters. Camshaft journal bearing surfaces and all camshaft rubbing surfaces except lobe tips were coated. The direct acting bucket shims were etched with a cross hatch pattern to a depth sufficient to sustain a SFL film coating on the shim rubbing surfaces subjected to high surface loads. The SFL coated valvetrain torque was evaluated and compared with uncoated baseline torque. Coating the cam bearing journal surfaces alone with II-25D SFL reduced valvetrain friction losses 8 to 17% for 250 to 2000 rpm cam speed range (i.e. 500 - 4000 rpm engine speed). When bucket tappet and shims were also coated with the SFL, further significant reductions in coated valvetrain friction were observed.

An integrated engineering approach using computer modeling, laboratory and vehicle testing enabled the Ford GT engineering team to achieve supercar thermal management performance within the aggressive program timing. Theoretical and empirical test data was used during the design and development of the engine cooling system. The information was used to verify design assumptions and validate engineering efforts. This design approach allowed the team to define a system solution quickly and minimized the need for extensive vehicle level testing. The result of this approach was the development of an engine cooling system that adequately controls air, oil and coolant temperatures during all driving and environmental conditions.

A single cylinder indirect injection diesel engine was used to evaluate the emissions, fuel consumption, and ignition delay of non-petroleum liquid fuels derived from coal, shale, and tar sands. Correlations were made relating fuel properties with exhaust emissions, fuel consumption, and ignition delay. The results of the correlation study showed that the indicated fuel consumption, ignition delay, and CO emissions significantly correlated with the H/C ratio, specific gravity, heat of combustion, aromatics and saturates content, and cetane number, Multiple fuel properties were necessary to correlate the hydrocarbon emissions. The NOx emissions did not correlate well with any fuel property. Because these fuels from various resources were able to correlate succesfully with many of the fuel properties suggests that the degree of refinement or the chemical composition of the fuel is a better predictor of its performance than its resource.

A model is presented which incorporates the key mechanisms in the formation and reduction of unburned HC emissions from spark ignited engines. The model includes the effects of piston crevice volume, oil layer absorption / desorption, partial burns, and in-cylinder and exhaust port oxidation. The mechanism for the filling and emptying of the piston crevice takes into account the location of the flame front so that the flow of both burned gas and unburned gas is recognized. Oxidation of unburned fuel is calculated with a global, Arrhenius-type equation. A newly developed submodel is included which calculates the amount of unburned fuel to be added to the cylinder as a result of partial burns. At each crankangle, the submodel compares the rate of change of the burned gas volume to the rate of change of the cylinder volume.

A flow network method was developed to predict the underhood temperature distribution of an automobile. The method involves the solution of simplified energy and momentum equations of the air flow in control volumes defined by subdividing the air space between the surfaces of the underhood components and the front-end geometry. The control volumes are interconnected by ducts with branches and bends to form a flow network. Conservation of mass and momentum with appropriate pressure-loss coefficients leads to a system of algebraic equations to be solved for the flow rates through each volume. The computed flow rates are transferred to a thermal model to calculate the temperatures of the air and the major vehicle components that affect the underhood environment. The method was applied to a 1986 3.0L Taurus and compared with vehicle experiments conducted in a windtunnel.

A four-stroke, spark-ignition engine is described that seeks to achieve high expansion ratio and low throttling losses at light load, whilst retaining good knock resistance at full load operation and without the need for expensive mechanical changes to the engine. The engine does, however, incorporate a second inlet (transfer) valve and associated transfer port linked to the intake port. The timing of the transfer valve is different from that of the main inlet valve. Load modulation is achieved by control of the gas outflow from the transfer port. A computer model of the engine is first validated against measured data from a conventional engine. Comparisons are made of incylinder pressure at part load conditions, total air flowrate through the engine and intake port air velocities as a function of crank angle position.

Combustion flame geometry calculation is a critical task in the design and analysis of combustion engine chamber. Combustion flame directly influences the fuel economy, engine performance and efficiency. Currently, many of the flame geometry calculation methods assume certain specific chamber and piston top shapes and make some approximations to them. Even further, most methods can not handle multiple spark plug set-ups. Consequently, most of the current flame geometry calculation methods do not give accurate results and have some built-in limitations. They are particularly poor for adapting to any kind of new chamber geometry and spark plug set-up design. This report presents a novel methodology which allows the accurate calculation of flame geometry regardless of the chamber geometry and the number of spark plugs. In this methodology, solid models are used to represent the components within the chamber and unique attributes (colors) are attached respectively to these components.

Computer simulation of the behavior of the automotive cooling system is becoming increasingly common, so as to reduce the dependency on costly testing. The simulation of transient cooling system behavior has become easier with the use of 1-D simulation tools. However, accurate prediction of transient coolant temperature after thermostat operation has been limited by the difficulty in accurately modeling the behavior of the automotive thermostat. Physical models of the thermostat are often inaccurate due to the complexity of the thermostat. Therefore an empirical model has been developed, which can be used to model any automotive thermostat, once a few simple tests have been conducted on the part. This thermostat model can be used in conjunction with a 1-D flow simulation tool to predict coolant transient temperature response during thermostat operation.

Exhaust gas air-fuel ratio (A/F) sensors are common devices in powertrain feedback control systems aimed at minimizing emissions. Both resistive (using TiO2) and electrochemical (using ZrO2) mechanisms are used in the high temperature ceramic devices now being employed. In this work a new mechanism for making the measurement is presented based on the change in the workfunction of a Pt film in interaction with the exhaust gas. In particular it is found that the workfunction of Pt increases reversibly by approximately 0.7 V at that point (the stoichiometric ratio) where the exhaust changes from rich to lean conditions. This increase arises from the adsorption of O2 on the Pt surface. On returning to rich conditions, catalytic reaction of the adsorbed oxygen with reducing species returns the workfunction to its original value. Two methods, one capacitive and one thermionic, for electrically sensing this workfunction change and thus providing for a practical device are discussed.

In assessing the sound quality of electric motors (e.g., seat, mirror, and adjustable pedal motors), the sensation of Fluctuation Strength - a measure of intensity or frequency variation - has become important. For electric motors, it is typically caused by variation in the load, creating frequency modulation in the sound. An existing method for calculating Fluctuation Strength proved useful initially, but more extensive testing identified unacceptable performance. There were unacceptable levels of both false positives and false negatives. A new method is presented, which shows improved correlation with perceived fluctuation in sounds. Comparisons are made to the previous method and improvement is shown through examples of objective-subjective correlation for both seat motor sounds and adjustable pedal motor sounds. The new method is also shown to match subjective data from which the original measure of Fluctuation Strength was derived.

We have developed a new wall wetting model to predict the transient Air/Fuel ratio excursion in a port fuel injected (PFI) engine due to changes in air or fuel flow. The quasi-dimensional model accounts for fuel films both in the port as well as in the cylinder of a PFI engine and includes the effects of back-flow on the port fuel films to redistribute and vaporize the fuel. A multi-component fuel model is included in the simulation; it gives realistic fuel behavior and allows the effects of different fuel distillation curves to be studied. The multi-component fuel model calculates the changing composition of the fuel puddles in the port and cylinder during the cycle. The inclusion of an in-cylinder fuel film allows the model to be used for cold start conditions down to 290 K. The model uses the Reynold's analogy to calculate the fuel vaporization process and uses a boundary layer calculation to solve for the liquid film flow.

A technique is presented that has been successfully demonstrated to non-intrusively and quickly sample gases typically found in PCV systems. Color Detection Tubes (CDTs) were used with a simple sampling arrangement to monitor CO2, NOx, O2, and H2O(g) at the closure line, crankcase, and PCV line. Measurements were accurate and could be made instantaneously. Short Path Thermal Desorbtion Tubes (SPTDTs) were used at the same engine locations for the characterization of fuel- and oil-derived hydrocarbon (HC) fractions and required only 50 cc samples. High engine loads caused pushover of blowby vapors as indicated by increased concentrations of CO2, NOx, H2O(g), and fuel HCs in the engines' fresh air inlets during WOT operation. Peak concentrations of blowby vapors were measured in the crankcase under no load and part throttle conditions. Oxygen concentrations always opposed the trends of CO2, NOx, and H2O(g).

A feedgas hydrocarbon emissions model that extends the usefulness of fully-warmed steady-state engine maps to the cold transient regime was developed for use within a vehicle simulation program that focuses on the powertrain control system (Virtual Powertrain and Control System, VPACS). The formulation considers three main sources of hydrocarbon. The primary component originates from in-cylinder crevice effects which are correlated with engine coolant temperature. The second component includes the mass of fuel that enters the cylinder but remains unavailable for combustion (liquid phase) and subsequently vaporizes during the exhaust portion of the cycle. The third component includes any fuel that remains from a slow or incomplete burn as predicted by a crank angle resolved combustion model.

The present work focused on modeling turbulent flame propagation combustion process using a direct chemical kinetics model. Firstly, the theory of turbulent flame propagation combustion modeling directly using chemical kinetics is given in detail. Secondly, two important techniques in this approach are described. One technique is the selection of chemical kinetics mechanism, and the other one is the selection of AMR (adaptive mesh refinement) level. A reduced chemical kinetics mechanism with minor modification by the authors of this paper which is suitable for simulating gasoline engine under warm up operating conditions was selected in this work. This mechanism was validated over some operating conditions close to some engine cases. The effect of AMR level on combustion simulation is given, and an optimum AMR level of both velocity and temperature is recommended.

New vehicle control algorithms are needed to meet future emissions and fuel economy mandates that are quite likely to require a measurement of ambient specific humidity (SH). Current practice is to obtain the SH by measurement of relative humidity (RH), temperature and barometric pressure with physical sensors, and then to estimate the SH using a fit equation. In this paper a novel approach is described: a system of neural networks trained to estimate the SH using data that already exists on the vehicle bus. The neural network system, which is referred to as a virtual SH sensor, incorporates information from the global navigation satellite system such as longitude, latitude, time and date, and from the vehicle climate control system such as temperature and barometric pressure, and outputs an estimate of SH. The conclusion of this preliminary study is that neural networks have the potential of being used as a virtual sensor for estimating ambient and intake manifold's SH.

The galvanostatic polarization method was used to determine the pitting potentials of candidate wrought aluminum alloys in inhibited ethylene glycol engine coolants. It was shown that the relative value of the pitting potential is an excellent measure of the long-term effectiveness of the coolants in preventing spontaneous pitting and crevice attack in the aluminum heat exchangers. The long-term effectiveness was determined by metallographic examination of aluminum heat exchangers subjected to a four-month, 50,000 mile simulated service circulation test.

The effects of engine operating conditions on the octane requirement and the resulting knock-limited output were studied on a single cylinder engine using production cylinder heads. A 4-valve cylinder head with port deactivation was used to study the effect of fuel octane, inlet air temperature, coolant temperature, air/fuel ratio, compression ratio and exhaust back pressure. The effect of the thermal environment was studied in more detail using separate cooling systems for the cylinder head and engine block on a 2-valve cylinder head. The results of this study compared closely with results found in the literature even though the engine and/or operating conditions were quite different in many cases.

The small-displacement direct-injection (DI) diesel engine is a prime candidate for future transportation needs because of its high thermal efficiency combined with near term production feasibility. Ford Motor Company and FEV Engine Technology, Inc. are working together with the US Department of Energy to develop a small displacement DI diesel engine that meets the key challenges of emissions, NVH, and power density. The targets for the engine are to meet ULEV emission standards while maintaining a best fuel consumption of 200g/kW-hr. The NVH performance goal is transparency with state-of-the-art, four-cylinder gasoline vehicles. Advanced features are required to meet the ambitious targets for this engine. Small-bore combustion systems enable the downsizing of the engine required for high fuel economy with the NVH advantages a four- cylinder has over a three-cylinder engine.

It is frequently useful to calculate the theoretical composition of the major components of vehicle exhaust. A software program has been written in Basic (or Quick Basic) which allows the convenient calculation of volume percents of CO, CO2, O2, H2, and H2O from fuel composition (H/C and O/C ratios), the water content (dew point) of the combustion air, and a chosen stoichiometry (air/fuel ratio). The program considers the Water Gas Shift reaction and the production of hydrogen under fuel rich conditions. The program is valid for both standard gasolines and oxygenated blends. Vehicle emissions data, collected to compare values calculated by the program with actual experimentally determined values from vehicle exhaust, show good agreement for measurements made at a series of air/fuel ratios ranging from lambda of 0.85-1.2.

A structural ceramic diesel engine has the potential to provide low heat rejection and significant improvements in fuel economy. Analytical and experimental evaluations were conducted on the critical elements of this engine. The structural ceramic components, which included the cylinder, piston and pin, operated successfully in a single cylinder engine for over 100 hours. The potential for up to 8-11% improvement in indicated specific fuel consumption was projected when corrections for blow-by were applied. The ringless piston with gas squeeze film lubrication avoided the difficulty with liquid lubricants in the high temperature piston/cylinder area. The resulting reduction in friction was projected to provide an additional 15% improvement in brake specific fuel consumption for a multi-cylinder engine at light loads.