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Technical Paper

Brake Integrated Hydraulic Actuation System Master Cylinder

This paper presents the design and operation of a new stepped bore master cylinder (fast-fill) which also integrates the rear brake proportioning valves and brake failure warning device in one major assembly. This design optimizes weight, performance and package together with several unique design features. It incorporates a combination of a plastic reservoir, permanent mold aluminum body, steel pistons, and minaturized steel proportioning valves resulting in a significant weight and cost reduction versus equivalent hydraulic actuation systems.
Technical Paper

A Comparative Study of the Effects of Fuel Properties of Non-Petroleum Fuels on Diesel Engine Combustion and Emissions

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.
Technical Paper

Distribution of Air Mass Flowrate between the Cylinders of a Carburetted Automotive Engine

The distribution of air mass flowrate between the cylinders of a 4-cylinder, carburetted automotive engine has been measured using a propane injection technique. The results show that over a wide range of operating conditions the engine has acceptably uniform distribution of air flow. At low- and medium-speed conditions the insertion of quite large obstructions into individual limbs is shown to have little effect on the air mass flows through these limbs. Only at high engine speeds and loads do these resistances have significant effect. The measured data are compared with corresponding predictions from a computer model of the engine and good agreement is shown.
Technical Paper

Oil Pressure Signatures for Engine Lubrication System Monitoring

This paper describes an application of signature analysis techniques to oil pressure signals of internal combustion engines for monitoring the status of an engine lubrication system. The dynamic characteristics of a lubrication flow network are presented. The state of the lubrication system is reflected not only in the mean or D.C. component, but also in higher frequencies of the signal. Experimental results are presented for both periodic and position locked components of the pulsatile signals. The signal characteristics are altered if a defect is present in the engine. Signal characteristics are affected due to perturbations introduced by the defect present downstream in the lubrication system. The changes in oil pressure signals are sensitive to oil temperature and proximity of the defect to the monitoring point. Results are presented to indicate limitations of such analysis techniques for lubrication system fault detection.
Technical Paper

Front Wheel Drive Engine Mount Optimization

This paper presents a guide for front wheel drive transverse engine mount optimization. The rationale for trying to achieve certain powerplant mode shapes and desirable frequency trends for these mode shapes is discussed. A mathematical proof is given for conditions which will ensure that the engine firing torque pulses excite only one engine mode. This will be shown to be desirable for satisfying the many conflicting design constraints. A review of various optimization procedures which were tried is discussed and a detailed explanation of the selected MONTE CARLO procedure is given. Extensive MOTRAN computer results are presented, both for a grounded engine and for a full vehicle.
Technical Paper

Hardware Effects on the Wear of Methanol-Fueled Engines

A 98-hour sequence test has been developed to study the wear of Ford OHC 2.3L methanol fueled engines. This test requires only half the test time of an ASTM Sequence V-D test used by many researchers, and yet provides sufficient severity to generate measurable bore wear to discriminate engine hardware changes. A portable fixture was designed to provide rapid, convenient, and accurate measurement of radial bore wear at a prescribed depth in the cylinder. The fixture can measure radial bore wear with accuracies to 0.004 mm. Its portability allows on-site measurement of engines on dynamometer test stands, or in vehicles with minimal engine disassembly. The test procedure and measurement fixture were used to quantitatively document the ring and bore wear effects of numerous variables, such as fuels, fully formulated lubricants, top ring configurations, coolant temperatures and flow patterns, intake heat addition, and fuel contamination.
Technical Paper

A Gasoline Engine Cycle that Permits High Expansion Operation with Reduced Part Load Throttling Losses by Modulating Charge Mass and Temperature

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.
Technical Paper

The Ceramic Gas Turbine-A Candidate Powerplant for the Middle-and Long-Term Future

The paper reviews our problems of energy availability in the middle and long-term future as well as our problems of environmental pollution and materials availability. Against this background the ceramic gas turbine engine is examined and shown to have potential as an attractive candidate powerplant for both the middle and long-term future. The paper reports on Ford's ceramic gas turbine program which is a systems development program encompassing all aspects of turbine ceramics technology---design, materials, fabrication processes, testing and evaluation.
Technical Paper

Engine Mass Air Flow Meter

Although it has long been recognized that tight air to fuel ratio control under all engine operating conditions should improve engine fuel economy and simplify emissions control, economical, precision and packageable devices for measuring these parameters have not been available for engine control application. Fuel and air input systems, consequently, have continued to rely on other alternate methods of controlling the air to fuel mix. In recent years, advancements in both sensor and electronic technology have begun to make available to the engine control systems engineer compact,high accuracy/reliability devices that offer possibilities of even tighter fundamental controls. At Ford Motor Company, one such car engineering concept that has been under development for several years is a precision engine air input measuring meter.
Technical Paper

Applied Photoelasticity for Engine Component Design Analysis

This paper discusses in detail three applications of photoelasticity to engine component design and failure analysis. This stress analysis technique provides whole field stress distribution and can also be used to optimize a design by obtaining even stress distribution. The applications discussed cover several aspects of photoelasticity such as two and three dimensional model analysis, stress freezing, thermal and mechanical loading simulation. These are some of the many investigations conducted by the authors and can be used as a guide to many other applications. The results of the analysis have been verified during endurance testing, but are not discussed in this paper.
Technical Paper

Engine Radiated Noise Prediction Modeling Using Noise Source Decomposition and Regression Analysis

An engine's radiated noise level is a very important attribute required for delivering customer satisfaction. Having an accurate radiated noise prediction capability during the planning, target setting, and initial design phases is critical to making the up-front decisions that enable the timely and cost efficient delivery of an engine that meets its radiated noise goals. This paper describes a simple radiated noise model that is based on a combination of regression modeling and simplified analytical modeling. The regression model uses measured data from multiple tests that can be broken down to noise sources such as mechanical, combustion, and accessory components. The simple analytical models are used to determine the parameters that the decomposed noise data is regressed against. The model developed in the paper is then compared to previous models suggested in the literature and to measured data from engines.
Technical Paper

A Predictive Model for Feedgas Hydrocarbon Emissions: An Extension to Warm Engine Maps

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.
Technical Paper

Exhaust Valve Thermal Management and Robust Design Using Combustion and 3D Conjugate Heat Transfer Simulation with 6-Sigma Methodology

Meeting increasingly stringent targets for vehicle performance, economy and emissions requires a deep understanding of the overall IC engine system behavior and the ability to optimize it considering all control and noise factors and their variations. The tradeoffs in exhaust gas temperature, exhaust valve temperature, engine performance, economy and emissions demand a combination of capable CAE analytical tools and a methodology capable of leading the design to a reliable and robust solution. This paper presents a newly developed methodology that uses a Ford in-house quasi-dimensional combustion model called GESIM (General Engine Simulation Program) and a 3D conjugate heat transfer (CHT) model to predict crank angle resolved exhaust gas temperatures and cycle average valve temperatures in a 6-Sigma context, which considers a wide range of engine factors and their variations, to determine a feasible robust design solution.
Technical Paper

On the Effectiveness of the Spatial Transmissibility to Drive the NVH Design of Cylinder Head Covers

Many suppliers and OEMs adopted the concept of transmissibility ratio as a method of choice to evaluate the NVH performance of cylinder head cam covers. The was defined as the transfer function between the cam cover and the cylinder head average vibrations. The was shown to be independent of the engine speed and declared to be a characteristic intrinsic to the cam cover system. This paper examines the correlation between the predictions and the measured cam covers sound power. For this purpose, a comprehensive study was conducted using several cam covers with different materials, designs and isolation systems. The results indicated a moderate correlation between the and the sound power for the isolated covers only. Analysis of the measured cam cover and cylinder head vibrations shows the potential cause for this weak correlation and demonstrates the need for improving the definition in order to accurately guide the cam cover NVH design.
Technical Paper

Material Characterization of Powder-Forged Copper Steels

Powder metal based copper steels have found increased use in automotive applications, an example being powder-forged connecting rods. A characterization study was conducted to determine the effects of carbon content and manganese sulphide addition on the mechanical properties and machinability of these materials. Steel powder mixes containing 2% Cu and various graphite contents, with and without a MnS addition were pressed, sintered and forged to full density. Forged samples were then tested for tensile properties, hardness and fatigue strength. Machinability was determined by measuring tool life during drilling tests. It was found that increasing the carbon content from 0.28 to 0.69% has little effect on fatigue properties of powder-forged copper steels although the tensile, strength increased as expected. The addition of manganese sulphide did not affect the mechanical properties measured, but was found to significantly improve the machinability.
Technical Paper

Experimental Evaluation of Tappet/Bore and Cam/Tappet Friction for a Direct Acting Bucket Tappet Valvetrain

Tappet/bore friction and torque at the camshaft were measured for a direct acting bucket tappet using a cam/tappet friction apparatus. Tappet/bore and cam/tappet friction torque and friction coefficient as a function of cam angle were derived from those measurements. The results showed that, for the particular geometry tested, tappet/bore friction torque accounted for about 13% of the total cam/tappet/bore friction torque at 250 cam rpm. This fraction decreased with increasing speed. Tappet bore friction was greatest at about ± 40 degrees of cam angle, where side loads on the tappet bore were highest. In contrast, earlier results for a center pivot rocker arm design showed tappet bore friction to be negligible.
Technical Paper

Effect of Sac Volume on Injector Performance

The “Sac” is a small volume within the fuel flow path of an electronic fuel injector. In this study, it is defined as the volume between the valve seat (fuel shut off point) and the entrance to the final metering orifice of the injector. This sac causes fuel injectors to deliver uncalibrated excess fuel when the engine is operated under closed throttle, high manifold vacuum conditions such as vehicle decelerations or idle. This paper describes a simple mass balance model used to predict the effect of the sac volume on injector fuel delivery under extreme operating conditions. The model prediction compares directly with experimental results for injectors with different sac volumes.
Technical Paper

The Effect of Mileage on Emissions and Emission Component Durability by the Fuel Additive Methylcyclopentadiencyl Manganese Tricarbonyl (MMT)

Vehicle emissions have been measured and the results statistically evaluated for a vehicle test fleet consisting of four Escorts and four Explorers using both a fully formulated durability fuel doped with methylcyclopentadienyl manganese tricarbonyl (MMT) at 1/32 gram Mn/gallon and the same fully formulated durability fuel without the MMT. The fleet was divided in half -- half with MMT and half without MMT doped fuel. This report covers emission measurement results at 5,000; 15,000; 50,000 and 100,000 miles of exposure to MMT doped fuel. A modified paired t-test is used to analyze the emission data obtained from all the fleet vehicles. The statistical evaluation of both feedgas and tailpipe emissions indicate that the use of MMT is detrimental to emissions of HC at the 15,000 mile; 50,000 mile and 100,000 mile levels of MMT exposure. As mileage is accumulated, the pronounced the effect on HC by the fuel additive MMT.
Technical Paper

High Speed Fuel Injection System for 2-Stroke D.I. Gasoline Engine

Two-stroke gasoline engines are known to benefit from using in-cylinder fuel injection which improves their ability to meet the strict fuel economy and exhaust emissions requirements. A conventional method of in-cylinder fuel injection involves application of plunger-type positive displacement pumps. Two-stroke engines are usually smaller and lighter than their 4-stroke counterparts of equal power and need a pump that should also be small and light and, preferably, simple in construction. Because a 2-stroke engine fires every crankshaft revolution, its fuel injection pump must run at crankshaft speed (twice the speed of a 4-stroke engine pump). An electronically controlled fuel injection system has been designed to satisfy the needs of a small automotive 2-stroke engine capable of running at speeds of up to 6000 rpm.
Technical Paper

Ford's All New 4.6 Liter SOHC V-8 Engine for the Lincoln Town Car

Ford is introducing the first high volume domestically designed and produced overhead camshaft V-8 engine As the first entry of a family of V-8 engines, the 4.6L 2 valve per cylinder engine was created to replace Ford's work-horse small block V-8 family of pushrod engines. That family of engines was first produced in 1962 in a 221 cu. in. version and have since evolved into the 302 cu. in. (5.0L) engine which previously powered the Town Car. Design goals of the engine family were: Higher horsepower output combined with reduced engine displacement Improved fuel efficiency and reduced emissions Reduced noise and vibration Advanced technology Precision manufacturing Improved quality and durability Program Execution was accomplished by extensive use of teamwork processes, including Cross Functional Teams (CFTs) among Design Engineering, Manufacturing Engineering, Suppliers, Purchasing and Vehicle Engineering.