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The effects of strain rate on the deformation behavior of several steels were investigated to find the most appropriate material for anti-crash parts of automobiles, such as front-side-members. Dual phase steel, TRIP steel, and work hardened steel showed higher dynamic to static yield strength ratios than solid-solution hardened steel. The dual phase steel absorbed a higher amount of energy during dynamic deformation than other steels with the same static yield strength due to its high strain rate sensitivity and high work hardening coefficient during dynamic deformation.

In order to increase the strength and formability of batch annealed sheet steels, design of experiment method was used to set up an experimental matrix with five factors, including C, Mn, P in steels, coiling, and batch annealing temperatures, at two levels. Effects of these factors were analyzed using analysis of variance and linear regression methods for cold spot and hot spot, respectively. Linear regression results showed that higher alloying element contents and coiling temperature will increase strength and deteriorate elongation, which is opposite to the effect of annealing temperature. Analysis of variance showed similar results to those of linear regression, except the effect of C on elongation and effect of coiling temperature on tensile strength and elongation are negligible for cold spot. For hot spot, effect of coiling temperature on tensile strength is small.

Galvanneal powdering was examined on a stabilized ultra low carbon steel substrate as a function of strain state using cup drawing and in-plane stretching experiments to simulate deformations encountered in production stampings. Significant powdering was encountered in drawing while minimal powdering occurred in in-plane stretching. Powdering was measured at specific locations and correlated with strains in those locations. A powdering map was generated in strain space using the experimental data. A few measurements of powdering on selected regions of an automotive stamped part are reported.

Resistance to dents and dings, caused by plant handling and in-service use, is generally recognized as an important performance requirement for automotive outer body panels. This paper examines the dent resistance improvements that can be achieved by maximizing surface stretch, through adjustments to the press settings, and substitution of a higher strength steel grade. Initially, the stamping process was optimized using the steel supplied for production: a Ti/Nb-stabilized, ultra low carbon (ULC) grade. The stamping process was subsequently optimized with a Nb-stabilized, rephosphorized ULC steel, at various thicknesses. The formed panels were evaluated for percent surface stretch, percent thinning, in-panel yield strength after forming, and dent performance. The results showed that dent resistance can be significantly improved, even at a reduced steel thickness, thus demonstrating a potential for weight savings.

The dent resistance of AKDQ, bake-hardenable, and IF Re-phosphorized sheet steels in both the as-received and biaxially prestrained conditions were evaluated. A laboratory dent test system for evaluating flat 76.2 mm diameter samples was designed and adapted to a standard universal test frame. Dent testing consisted of measuring the loads and displacements associated with the incremental quasistatic penetration and withdrawal of an indenter into the center of a circular sheet sample mechanically restrained at its perimeter. Dent resistance was characterized by a critical amount of residual displacement. Both experimental measurements and theoretical predictions demonstrate an increase in dent resistance with prestrain up to a maximum followed by a decrease due to thinning. Correlations between dent resistance, tensile properties, and the strain within the dented region indicate that the dent performance depends on the low strain, strain hardening behavior of the material.

Diesel combustion and exhaust gas emissions under transient operation (when fuel amounts abruptly increased) were investigated under a wide range of operating conditions with a newly developed gas sampling system. The relation between gas emissions and piston wall temperatures was also investigated. The results indicated that after the start of acceleration NOx, THC and smoke showed transient behaviors before reaching the steady state condition. Of the three gases, THC was most affected by piston wall temperature; its concentration decreased as the wall temperature increased throughout the acceleration except immediately after the start of acceleration. The number of cycles, at which gas concentrations reach the steady-state value after the start of acceleration, were about 1.2 times the cycle constant of the piston wall temperature for THC, and 2.3 times for smoke.

It is well known that a high-pressure fuel injection is effective for the reduction in particulates and smoke emissions. Exhaust gas recirculation (EGR) is effective for the reduction in NOX emission. In this study an experiment aiming to understand more comprehensive combustion under the condition of EGR and high-pressure fuel injection was carried out by using gas sampling method for the purpose of understanding what occurred inside the spray before and after combustion. The number of combustion cycles in this engine can be controlled in order to change EGR conditions by adjusting the residual gas concentration in the cylinder. Main results were: (1) Close to the nozzle tip, the sampling gas data showed little reaction which implies that combustion never occurs in this area during the injection period. (2) In the case of high-pressure fuel injection O2 concentration decreased faster and air dilution was more active and earlier.

The dual-throat jet technique has been successfully used to improve cold-starting of the swirl-type IDI diesel engines. It has been proven that, with the aid of the second throat connecting the swirl chamber and the main combustion chamber, the cold-starting process was more stable, quiete and clean. However, the understanding of the mechanism of this technique is far less than satisfied as regarding to the better control and further development. An intensive fundamental experimental investigation of the transient process of the ignition and combustion at cold-staring had been conducted on a swirl-chamber IDI diesel engine with the help of high-speed photography. Based on the results of this investigation, the following conclusions have been approached: 1) There exist three types of heat release rate pattern at the cold-starting.

Combustion Characteristics of a diesel fuel spray impinging on a wall were studied, using a constant volume combustion vessel. Pressure and temperature inside the vessel. and fuel injection specification were set at the typical values of small DI diesel engines of 90-100 mm cylinder bore size. The indicated pressure analysis and combustion observation indicate that present analysis enables the evaluation of the mixture formation affected by impingement wall, corresponding to a small actual DI diesel engine. By lowering impingement wall temperature from 840 K to 620 K, ignition point shifts upstream along the spray from a portion near the wall, and ignition delay is shortened. Although ignition occurs earlier at shorter impingement length, its ignition time difference become less at shorter ignition delay condition, where, however, the heat release rate changes greatly and it gives a maximum at a certain impingement length.

Heat release and instantaneous injection rate data was obtained from a series of experiments on a 121mm bore, single-cylinder, deep-bowl, non-swirling D.I. diesel research engine, using a variety of fuel injection pump builds. Results from tests at constant air-fuel ratio and constant start of combustion angle show that increasing the mean fuel injection kinetic energy (M.I.K.E.) at a given engine speed reduces the heat release time and increases the fuel-air mixing rate. Also, at constant fuel injection kinetic energy, increasing the engine speed increases the fuel-air mixing rate. These experimental trends have been interpreted with the aid of a novel but mathematically very simple analytical approach, based on the hypothesis that all fuel-air mixing in a DI diesel combustion system is promoted by kinetic energy inputs. A “Combined Mixing Efficiency” has been identified which appears to be a characteristic constant of a DI diesel combustion system geometric configuration.

In this study a new water injection system was applied to an 11 liter naturally aspirated DI diesel engine in order to reduce exhaust emissions. In this system, the water and fuel were arranged in the injection nozzle during the time between injections as fuel, water and then fuel. The fuel and water were then injected into the cylinder in that order. The tests were conducted at several engine operating conditions from the Japanese 13 mode test cycle to clarify effects of water injection on exhaust emissions and fuel consumption. The results showed that NOx reduction was directly proportional to the relative amount of water injection, regardless of engine speed and load. By using the optimal relative amount of water injection at each engine operating condition, total NOx and particulate matter (PM) in the Japanese 13 mode test cycle were reduced by 50% and 25%, respectively, without a fuel consumption penalty.

Ambient gas density and fuel vaporization effects on the penetration and dispersion of diesel sprays were examined over a gas density range spanning nearly two orders of magnitude. This range included gas densities more than a factor of two higher than top-dead-center conditions in current technology heavy-duty diesel engines. The results show that ambient gas density has a significantly larger effect on spray penetration and a smaller effect on spray dispersion than has been previously reported. The increased dependence of penetration on gas density is shown to be the result of gas density effects on dispersion. In addition, the results show that vaporization decreases penetration and dispersion by as much as 20% relative to non-vaporizing sprays; however, the effects of vaporization decrease with increasing gas density.

In a free piston engine the piston is neither connected to a crankshaft mechanism nor to any other kinematic system. Instead the piston movement is determined by the free forces that act upon it. This difference between the kinematic principle of the crankshaft engine and the free piston principle has a significant influence on the combustion process. In this paper the combustion process in a free piston engine is described on the basis of experiments. The experimental data were obtained from measurements on the free piston engine that has been developed by the Dutch company Innas. This article discusses the influence of the free piston principle on cold start, ignition delay, heat release, heat transfer, indicated efficiency and emissions. In the optimum point the engine has an indicated efficiency of 51%, a NOx emission of 6 gr/kWhi and a soot emission corresponding to a Bosch Filter Number of less than 0.5.

A method for making value tradeoff decisions between fuel economy and acceleration performance is demonstrated. Attribute value as defined by the S-Model Theory of Quality [1,2] is measured for the attributes of fuel economy and acceleration performance through a vehicle driving clinic. Willingness-to-pay values are found for the attributes at several different levels. The willingness-to-pay values are then used to refine the empirical and economic value curves previously determined for those attributes.

With VA/VE/VM techniques properly applied, net revenues can be increased by appropriately decreasing cost and increasing cost.

A methodology is described for estimating the changes in value of an automobile as a function of changes in its leg room, head room, and shoulder room for passengers in the front and rear seats. Value curves are computed as a function of these dimensions based upon the distribution of the sizes of men and women and upon the stated willingness to pay for extra roominess given by respondents in a survey.

This paper contains both theorems and correlations based on the idea that there is a uniform metric for measuring the complexity of mechanical parts. The metric proposed is the logarithm of dimension divided by tolerance. The theorems prove that, on the average, for a given manufacturing process, the time to fabricate is simply proportional to this metric. We show corrleations for manual turning (machine lathe process), manual milling (machine milling process), and the lay-up of composite stringers. In each case the accuracy of the time estimate is as good as that of traditional cost estimation methods, but the effort is much less. The coefficient for composite lay-up compares well to that obtained from basic physiological data (Fitts Law).

Enhanced information management techniques made available through emerging Information Technology platforms hold a promise of providing significant improvements in both the effectiveness and efficiency of developing complex products. Determining actual management implementations that deliver on this promise has often proven elusive. Work in conjunction with the Lean Aircraft Initiative at MIT has revealed a straight forward use of Information Technology that portends significant cost reductions. By integrating previously separate types of data involved in the process of product development, engineers and designers can make decisions that will significantly reduce ultimate costs. Since the results presented are not specific to particular technologies or manufacturing processes, the conclusions are broadly applicable.

The effect of Value Engineering on vehicle development has been successfully applied to facilitate automotive sub systems. The results have dramatically supported the Concurrent Engineering process and also helped identify problems early on in the development process, and also facilitated the problem resolution process early in the conceptual phase. This work includes results from sub system clinics and the concept alternative phase. The objectives of this paper is to: Explain the purpose and benefits using Customer FAST diagramming to understand end user's and/or owner's needs and desires as they relate to vehicle subsystems Describe the features of a Customer FAST diagram Explain how to construct a Customer FAST diagram Explain how to use the information generated from a Customer FAST diagram.

Value Engineering (VA) has been applied in the automobile industry for the past 20 years. Over this period of time hundreds of millions of dollars have been saved annually. In addition, a multitude of product improvements (quality, reliability, serviceability, etc.) has resulted. An expansion of these very beneficial efforts is Customer Focused Value Engineering (CFVA). CFVA integrates the customer's wants, needs, concerns and perceptions, into a VA study. This can result in products that better meet the real needs of the customer and help to avoid flaws in designs that keep customers from purchasing your product.