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The growing emphasis on reducing automobile weight is likely to lead to the use of increasing quantities of high-strength, cold-rolled steel sheet in the near future. The reasons for this probable trend (such as production restrictions on producing hot-rolled sheets having thicknesses below 0.070 in and potential weight savings from thinner body panels) are reviewed briefly. Because many steel producers are developing new steels and practices to expand their range of high-strength, cold-rolled sheet grades, the technical approaches available for producing high strengths in cold-rolled steel sheets are also reviewed. Possible methods for increasing the strength of steel sheets are discussed.

Four families of low-carbon, high-strength cold-rolled (HSCR) sheet are discussed, exhibiting minimum yield strengths of 40 to 140 ksi. The relative merits of the various grades are analyzed in terms of important fabricating and selection criteria: strengthening capability, planar anisotropy, formability, impact loading response, weldability and cost reduction. Paralleling the increase in strengthening capability in HSCR was an increased planar anisotropy and variation in formability within the various families. The impact loading of all cold-rolled grades showed increased yield strengths and energy absorption; the weldability of the different grades varied widely depending upon strengthening mechanisms, strength level, and chemistry; the cost reductions possible with the HSCR decreased as the degree of formability required in the finished part increased. Generally, gauge reductions of 6% to 34% were found to be necessary to offset cost extras for different grades of HSCR sheet.

High-strength cold-rolled sheet steels offer a potential to accomplish weight savings through gage reductions. However, the reduced formability which accompanies increased strength presents difficulties in the application of these steels for sheet metal stampings which require the formability equivalent of deep-drawing steels. A new deep-drawing sheet steel is being developed which overcomes the formability limitations of high-strength cold-rolled steels. Parts made from this steel can be uniformly strengthened to a high yield strength, up to 120,000 psi (827 MPa). Strengthening is accomplished by a 1200°F (921°K) heat treatment in a controlled atmosphere which results in internal nitridation. The nitrides formed by the alloying elements in the steel provide precipitation hardening. No distortion of the parts results from the heat treatment. The effect of heat-treating variables on tensile properties, weldability, fatigue, and toughness, are discussed.

Increasing secondary powerloads, advanced technology components, varied installations, and increased emphasis on cost and performance provide the requirements against which the engine project engineer must seek a balance during the conceptual, design, and development phases of an engine program. This paper reviews the requirements for advanced engine secondary power systems and some of the trends which are developing for future propulsion systems.

A new NATO patrol hydrofoil missile (PHM) is being developed, with the first lead ship nearing completion. The automatic control system (ACS), which provides the foilborne vehicle control, is newly developed for PHM. The ACS development evolved primarily from two previous hydrofoil control systems: Tucumcari and High Point. The ACS functional configuration was evolved using a highly developed digital simulation of the craft, control hardware, and sea conditions. Extensive failure mode and effect analyses were used to evolve a ship/control system configuration which is fail-safe for single-level failures within the system. From the overall performance, stability, and failure analyses, significant evolutions in the control system configurations resulted. The ACS hardware is newly developed for PHM, building around new families of integrated circuit building blocks.

Development and application of computer analysis to the flow system of the internal combustion engine is discussed. Particular attention is directed to the crankcase-scavenged, two-stroke-cycle, spark ignition engine, with the objective of optimizing the relationships between its complex transient flow processes and its basic mechanical simplicity. The aspects of specific output and fuel consumption, as well as those of the emission of noise and other obnoxious constituents of the exhaust, are considered. A systematic procedure is presented for determining the most practical port and duct dimensions for a new engine application.

Teledyne Continental's new Red Seal industrial engine line incorporates the Controlled Pressure Combustion System (CPCS) featuring emissions control, fuel efficiency and driveability, without sacrificing maximum power. These new, low maintenance engines are based on time-proven mechanical components with a new cylinder head, carburetor and electronic ignition. The complete R & D history of the program is presented, covering cylinder head, carburetion and ignition system. The paper describes an Automotive Program with two cars, matched and optimized to meet the 1975 Light Duty Automotive Standards without using any exhaust after treatment or other emissions control devices.

In an Energy Management Bumper System (EMBS) maximum energy-absorption efficiency is achieved with a “square wave” load/deflection response. The laboratory and barrier impact tests conducted in this study show that elastomeric columns provide essentially square wave response during the buckling stage of column deflection. Of the materials tested, high diene-low Mooney EPDM (terpolymer of ethylene, propylene and a diene) materials fabricated into hollow cube absorber units exhibited square wave efficiencies of 85-90% and were found to be the most suitable elastomers for an EMBS application. The efficient use of the elastomeric absorbers in an EMBS was accomplished by placing a metal face plate in front of the units to distribute the impact force across the face of the vehicle. This concept was applied to an engineering design for a 3000 lb. vehicle EMBS that would handle impacts at 5 mph in compliance with Federal Motor Vehicle Safety Standard No. 215.

A modified version of the pneumatic air cushion bumper has been incorporated into the basic design of a prototype automobile designed to provide improved structural performance during front, side, rear, and rollover collisions. A simple air bladder, recessed within a high-strength bumper bar, was supported by the front cross member of a modified frame which also served as a supplementary volume to reduce peak pressures and loads. Check valves were located between the bladder and the frame chamber to limit energy of rebound. Test results showed that the design is suitable for incorporation into vehicles intended to withstand barrier crashes of 5-10 mph.

During the past two decades, front-wheel-drive architecture has grown enormously in Europe. This trend can be explained by the need to provide compactness, large inside space, and good road holding. The paper describes technical problems that arise when designing a front-wheel-drive car and quotes the various technical solutions in current use. The authors conclude that a preference for front-wheel drive will last for a long time.

The performance of a hydrogen-supplemented fuels system is predicted using a semiempirical model. The prediction of this model is compared to data obtained during engine dynamometer tests of a hydrogen generator/multicylinder engine system. The test data and the predictions are also compared to the fuel consumption and emissions of the same engine in its stock configuration and indicate that the hydrogen-supplemented fuels system can improve BSFC 10-15% and simultaneously reduce NOx emissions to a level consistent with the 1977 EPA standard. The performance of an optimized hydrogen generator/engine system is estimated. With these comparisons and estimates used as a basis, the potential of the hydrogen-supplemented fuels system is identified.

Research is demonstrating that it is possible to significantly reduce the in-cab noise levels of the Army's current truck fleet, with accompanying exterior noise reduction. Results are applicable to future Army trucks as well and are reported on a program utilizing a 5-Ton Army Truck. This type of truck was found generally to exceed the applicable limits established in the new MIL-STD 1474, “Noise Limits for Army Material.” The program identified major noise sources and important paths for sound to enter the cab and resulted in the selection of optimum sound absorption, sound barrier and vibration damping materials. The effect of a prototype exhaust system and its placement relative to the cab and the importance and optional means of controlling cooling fan and engine noise were also investigated.

A mathematical model describing the Wankel engine combustion process is developed to evaluate the effects of apexseal leakage on NO emissions. It is assumed that leakage occurs only during combustion and expansion and that only unburned gas leaks out during combustion and that only unburned gas leaks out during combustion and that during expansion, only burned gas leaks out. A parametric study is performed to show the effects of such variables as equivalence ratio, compression ratio and engine speed. An experimentally obtained pressure time trace is used to show the accuracy of the model predictions. It was found that under normal operating conditions (near F = 1), reductions in apex-seal leakage area will not cause an increase in NO emissions and that below 2500 rpm, mass leakage drastically increases with further reductions in speed.

Measurements were made of exhaust histories of the following species: unburned hydrocarbons (HC), carbon monoxide, carbon dioxide, oxygen, and nitric oxide (NO). The measurements show that the exhaust flow can be divided into two distinct phases: a leading gas low in HC and high in NO followed by a trailing gas high in HC and low in NO. Calculations of time resolved equivalence ratio throughout the exhaust process show no evidence of a stratified combustion. The exhaust mass flow rate is time resolved by forcing the flow to be locally quasi-steady at an orifice placed in the exhaust pipe. The results with the quasi-steady assumption are shown to be consistent with the measurements. Predictions are made of time resolved mass flow rate which compare favorably to the experimental data base. The composition and flow histories provide sufficient information to calculate the time resolved flow rates of the individual species measured.

This paper reports on some recent work performed to establish the effectiveness of exhaust gas recycle as a knock suppressant in spark ignition engines, and to determine the effect of fuel and engine operating conditions on knock-limited engine performance and NOx emissions. Performance was evaluated with two different fuels: ASTM isooctane and ASTM 80 octane. With ASTM 80 octane fuel, operating near stoichiometric, the higher knock-limited compression ratio (klcr) resulted in a break mean effective pressure (bmep) which was constant for moderate recycle, falling only with high recycle rates. Brake specific fuel consumption (bsfc) decreased with recycle to a minimum, and then increased for higher recycle rates. For lean mixtures, however, bsfc increased steadily with recycle. Performance was similar with the isooctane. The performance recovery for stoichiometric and rich mixtures (low to moderate recycle) was attributed to the higher klcr and changes in the specific heat ratio.

This paper provides a user oriented description of techniques for the measurement and analysis of engine cylinder pressures. These techniques were developed for piezoelectric transducers and for digital systems of data acquisition and analysis. Test cell procedures are described for transducer preparation and calibration, and for association of each pressure with its appropriate crank angle. Techniques are also described for evaluating the accuracy of pressure data and for eliminating specific errors. Two examples of uses for pressure data are discussed: the calculation of heat release rate in conventional engines, and the computation of internal flows in divided chamber engines.

Attention in the United States is centering on investigations of lighter materials, more efficient structures, impact compatibility between cars, as well as between structure and restraints and simulation of collisions using both mechanical and computer techniques. This paper summarizes investigations as well as safety effects.

Obtaining vehicle fuel economy data in conjunction with chassis dynamometer emissions testing is a useful, convenient technique. Data derived in this manner, using EPA city and highway driving cycles, are in wide use. Fuel economy results obtained by carbon mass balance calculation of carbon containing compounds in the vehicle exhaust are at least as accurate and repeatable as those obtained by direct measurement of fuel consumed. Nevertheless, the overall chassis dynamometer-carbon balance fuel economy test yields undesirable variation of results and needs refinement. Major factors influencing the accuracy and repeatability of test results are: CO2 measurement accuracy; variations in following the driving cycle; vehicle-dynamometer interface conditions; and associated calibration, calculation, test technique and procedural methods and controls employed.

As part of its ESV evaluation effort, Dynamic Science has recently conducted vehicle-to-vehicle aggressive testing of the large AMF ESV with two small Fiat ESVs (Fiat 2,000-pound and Fiat 2,500-pound classes) at a closure speed of 75 mph. Preliminary analyses of crash test results are presented in this report. The vehicle-to-vehicle tests were highly successful in that structural integrity of the Fiat passenger compartments was adequately maintained. The AMF vehicle's hydraulic subsystem absorbed a significant portion of the crash energy in its 20-inch stroke, thus offering reduced aggressiveness to the small Fiat vehicles. However, human survival in terms of meeting current occupant injury criteria was not evaluated since dummies were not included in this preliminary test series. Such an evaluation is planned as part of future phases of this ESV evaluation program.