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Polymeric mineral oil additives are exposed to mechanical and thermo-oxidative degradation processes in the engine. For long lasting efficiency, they must show the highest possible stability to such attacks. The degradation processes are evident from and distinguishable by the molecular weight distribution of the polymer which can be measured with great accuracy by gel permeation chromatography (GPC), even for used oils. Results of such measurements are given for various types of VI improvers (polyalkyl methacrylates, ethylene-propylene copolymers and hydrogenated styrene-diene block copolymers) after exposure to Diesel and Otto engines. The influence of mechanical and thermo-oxidative degradation is discussed by means of model calculations. Comparative viscosity data elucidate the picture obtained from the distribution measurements.

With the advent of high speed computers, dynamic simulation of an automobile body has become a reality. The present work will discuss methods to develop a body model of manageable size which will give good correlation with tests and can also be used as a practical design tool. The basic approach is to model each component as a separate entity and then combine the components into a system model, a “Building Block Approach.” Finite element mesh considerations and modeling difficulties are discussed. An example of a vehicle body is presented to illustrate the approach.

Low-frequency interior noise in the automobile passenger compartment can be significantly affected by the vibration behavior of the body panels which surround the enclosed cavity. This paper reviews a finite element method for computing panel-excited interior noise and outlines an approach for identifying potentially noisy panels adjacent to the passenger compartment. To illustrate the potential of the analytical method, it is applied to a production automobile. A structural modification suggested by the procedure is shown to significantly reduce the low-frequency interior noise to which the occupant is exposed. Experimental verification of the method is presented.

A formulation is presented for the static and transient analysis of sheet metal structures involving very large displacements and rotations and elastoplastic material behavior. The geometrical nonlinearity can be treated by the decomposition of the element displacements into rigid body and deformation displacements. The elastoplastic formulation is based on the Mises yield criterion with isotropic strain hardening. The equations of motion are integrated by either the explicit or implicit schemes. Elements employed include the spring, three-dimensional beam, and plate element. Internal force or moment releases and rigid links are provided for beams.

A cost-effective early indicator of frontal barrier performance relative to government and corporate goals has been provided by half-scale metal models. These models provide direct indications of steering column kinematics and performance of specific components with respect to the windshield intrusion zone. Some indications of fuel system integrity and windshield retention evaluations have been inferred from half-scale model barrier tests. Model tests have provided early standard barrier data on vehicle crush modes and distances, barrier loads, and deceleration rates, in addition to generating data beyond what is available in standard barrier tests.

Vehicle energy in head-on or rear-end collisions is mainly absorbed by the front or rear longitudinal members. This paper describes the methods of calculation of crush load and the energy absorbed during the static and dynamic crush of the sheet metal members with closed-hat section together with attached flanges or walls. Calculated results were compared with experiments including full-size automobile collisions. It is expected that the analysis considering the strain rate sensitivity will provide more accurate design information for improved automobile crash-worthiness.

This paper summarizes the correlations obtained between Cold Cranking Simulator viscosities and gasoline and diesel engine cranking data on 17 commercial engine oils. These engine oils include the new synthetic 5W/20 oils. The ability of an oil pumpability bench test to predict the pumpability properties of these 17 oils in a gasoline engine is also presented. The Cold Cranking Simulator Viscosities measured at temperatures from -40°F (-40°C) to 32°F (0°C) were studied to determine the necessity of measuring CCS viscosities of each “W” graded oil at its minimum expected use temperature.

Investigations using 4 monograde and 3 multigrade engine oils were performed by cold cranking an automotive engine to determine whether or not there is friction reduction due to the pseudoplastic behaviour of the multigrade engine oils. A comparison of the oils using viscometers indicated the viscometers ability to predict the “engine viscosities” over a temperature and shear rate range. Furthermore, this work determined whether results of viscometric measurements could be confirmed with the test engine. An answer was found to the question of the amount of hydrodynamic friction encountered when starting an automotive engine at low temperatures.

This paper illustrates how experimental design techniques can be employed to obtain an accurate assessment of multigrade Heavy Duty (HD) performance in the field. Compared to monograde (SAE 40) oil, the use of SAE 15W/40 oil was found to improve vehicle fuel mileage (MPG) as well as oil economy (MPQ). The demonstration, conducted in two groups of 10 city buses each in regular service, was structured to dampen out the effect of numerous incidental variables. Statistical data analysis indicate a “most probable” improvement in fuel mileage of 2.7% as well as a 47% increase on multigraded oil economy.

Thermosetting liquid urethanes processed by reaction injection molding (RIM) can be reinforced with glass fibers. Special considerations of both the materials and the process system elements are required due to the characteristics of the reinforcement. Typically, slurries are prepared with milled glass fibers and one or both of the liquid urethane components. Then the urethane components are combined with mechanical and/or impingement mixing and injected into a mold. The resulting composites show increased stiffness and reduced thermal expansion due to the glass fiber reinforcement. These new material systems are expected to be used in many applications requiring good dimensional stability over a wide temperature range.

Sheet molding compound (SMC) has been used for functional or fascia automotive parts such as front and rear panels for several years. When properly formulated, processed, and molded, SMC has a potentially substantial role in the manufacture of more structurally demanding automotive parts. Through variations in the materials, equipment and processing techniques, different types of SMC can be produced. These are random fiber SMC (SMC-R); continuous fiber SMC (SMC-C); and directional fiber SMC (SMC-D). Representative formulations show how static mechanical properties are dependent upon glass content, glass orientation, and on the test temperature. Based on equivalent performance, these systems are lighter in weight than steel and are generally less costly, on a material basis, than aluminum.

The addition of a high molecular weight Silicone Fluid to most thermoplastics results in numerous processing advantages and cost savings. These fluids are mechanically blended with the resin melt to form stable polyblends. Addition to injection molding equipment or extruders can be accomplished either by utilizing a small metering pump or adding the fluid in a pelletized concentrate form similar to color concentrates. Excellent dispersion of the fluid in the resin results when done properly by either method. The fluid remains in the molded or extruded part in the form of small cells or droplets 2 - 4μ in size. The fluid exhibits no tendency to migrate or bleed. Fabricated parts may be decorated without the need for part cleanup.

This paper investigates the dynamic response characteristics of multilayer panels containing polyurethane foam layers. Results of driving point impedance tests on multilayer beam and circular plate structures in the frequency range 200hz - 3khz are compared with corresponding results obtained using commercial damping coatings. It is shown that configurations consisting of metal and solid polymer facings with foam cores exhibit highly attenuated response at selected frequencies. The hypothesis that the layered foam configuration acts as a dynamic vibration absorber is confirmed using a mathematical model of a sandwich beam which permits transverse deformation of the core.

Reduction in vehicle weight is a key goal for today's automobile design. This is being accomplished, in part, by replacement of metal components with lighter weight, multifunctional engineering plastics and composites. Additional weight reduction potential exists, however, through the use of high performance plastic parts from aramid and polyimide resins. The weight reducing value attributable to parts from these materials emanates from their high performance properties, and not necessarily their light weight. Superior properties allow the aramid and polyimide parts to be used in applications involving bearing loads, moving contact speeds and temperatures found too severe for other plastics. The principal benefit of their use is the designer's ability to downsize companion metal parts and to more readily incorporate lightweight metals such as aluminum.

During the last decade Powder Forging, a technique by which very precise components of high mechanical integrity and requiring minimal machining can be produced, has been the subject of intensive development activity. Powder Forging has now reached maturity; many parts are in volume commercial production, and all indications are that growth prospects are excellent. Users of parts are becoming increasingly aware of the machining, labour, investment and energy savings that can arise from adoption of the process. GKN Forgings Limited now has about thirty parts in commercial production, and a new self-contained operating Company has been established devoted entirely to Powder Forging. The paper reviews the current status of Powder Forging and describes by reference to actual components the economic and technical factors that dictate the types of parts that are best suited to manufacture by this method. Future growth predictions for Powder Forgings are discussed.

Automobile panels are stiffened in a variety of ways to meet engineering design criteria. Current example panels are numerous and include the roof, deck lid, hood, floor pan, etc. If lightweight, low modulus materials (e.g., aluminum, sheet molding compound) are to be considered for automobile panels, it can be anticipated that some form of stiffening will be necessary. In this paper, one particular type of stiffened panel, a two-layer panel consisting of a trapezoidally corrugated plate and a flat plate fastened together, is examined analytically and experimentally. A technique for modeling the panel with finite elements is developed. Rather than assigning “smeared-out” properties to the stiffeners, the fidelity of the panel is retained by modeling it as a double-layer structure (instead of as a plate) so that local deformations are also allowed.

An easy-to-use pre-processor system through which finite element analysis can be applied to routine design works is needed. We have developed a general purpose pre-processor system to be used for body structures and a number of other automobile parts. It can apply to shell, beams and/or solid structures, and has functions to generate input data, to check structures by drawing and to calculate the section constants of beam elements. It has become possible to discuss the detail design of structures because we could obtain a fine mesh models easily from complicated structures such as a automobile body.

The moving baseline of conventional engines and passenger cars utilizing such engines in the period 1975-1985 is developed from a review of recent trends in vehicle design and conventional engine and transmission development. The moving baseline is given in terms of engine specific weight and volume and vehicle fuel economy and energy intensity on both the EPA urban and highway cycles. Recent advances in conventional engine and vehicle design have lead to significant improvements in all the baseline areas. These improvements are discussed quantitatively in the paper.

Recent improvements in digital microprocessor hardware have given impetus to synthesizing a consistent set of central-processor engine-system control laws. As an approach to the problem, algorithms for control of airflow, EGR and spark advance were postulated, considering interactions of engine torque, fuel consumption, exhaust emissions, cold-starting and driveability. Development of an analog, real-time driver/vehicle model provided appropriate transient vehicle loads to the experimental engine/transmission/digital controller implementation throughout cold-start vehicular driving cycles. A Transient System Optimization procedure applied continuously over the federal urban driving schedule, including cold start, validated the postulated control laws.

This paper describes a new 6 cylinder, inline diesel which has been developed to power medium sized trucks and for industrial applications and which is currently in monthly production of 2,000 units. The engine is characterized by the use of direct fuel injection system, square toroidal combustion chamber, glow plug as a starting aid, thin dry chrome plated cylinder liners, engine stop system using air shutter, and newly-developed variable speed RLD-K governor with torque control cam, all of which are discussed here from aspects of design and experiment. Also covered are family engine concept and emission and noise control approaches.