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Recent design changes in high pressure diesel injection pumps have increased the heat input to the fuel beyond acceptable levels. This paper will discuss the source of the extra heat, its effects, and various ways of dissipating it. The advantages and limitations of the various methods of fuel cooling are explained.

The purpose of this paper is to recommend the criteria to be considered when selecting thermal insulation to improve the durability of exhaust system components. This paper focuses specifically on the features and benefits of one high temperature insulation alternative, ceramic fiber, and provides a concise comparison against lower performance glass and mineral fiber alternatives.

Description of the design and evolution of a Thermal Component Test Rig capable of simulating the thermal environment normally encountered by the underbody, floorpan, carpeted floors and occupants of automotive vehicles.

The strengths and weaknesses of engine coolants based on organic acid inhibitors are investigated. Recently, this technology has been approved for use by major OEM's. The coolants are expected to have a service life of at least 5 years/160,000 km as compared to the recommended 2 years/48,000 km for conventional silicate inhibited coolants. Laboratory performance tests of commercially available ethylene glycol based coolants and experimental propylene glycol based coolants are presented. These include physical properties measurement, ASTM corrosion tests, compatibility of OA and silicate coolants, tests to stress coolant performance, and electrochemical tests.

This paper presents a lumped parameter method for whole circuit simulation of vehicle cooling systems using the Bathfp simulation environment. The dynamic performance of a 1.8 litre internal combustion engine cooling system is examined. The simulation is compared with experimental data from a test rig incorporating a non-running engine with external heat source and a good correspondence is achieved. The background to the modelling approach is described. It is shown that simulating cooling systems with Bathfp offers the designer the flexibility to assess component sensitivity and changes in system configuration which will aid the process of cooling system optimisation.

This paper presents an investigation of the effect of fouling by considering a tube and plate fin geometry for which performance characteristics are well defined. By matching a particular heat exchanger to a given fan it can be shown that the air-side heat transfer coefficient increases as the air-side passages become progressively blocked, reaching a maximum close to the fully blocked condition. For moderate fouling this increase largely compensates for the change in mean temperature difference brought about by the variation in air flow rate, giving an overall performance very close to that for the clean condition.

The utilization of the exhaust waste heat from engines is now well known and form the basis of many combined heat and power installations. The combination of a thermal power cycle and a refrigerant cycle, however, been the subject of little interest in the past. The paper explores from a theoretical stand point the possibility of utilization of the exhaust gases of a turbocharged Diesel engine as an energy input to a vapor absorption refrigeration system for producing a cooling effect for the combination of pre and inter cooling of the charge air, which is a modified form of the intercooling systems.

The effects are described in aluminum brazing of a phenomenon known as Liquid Film Migration (LFM). This is primarily encountered when -O temper parts are formed and subsequently brazed. If the combination of material homogenization, alloy and cold work is such that the material does not recrystallize totally before the brazing temperature is reached, then the system begins to equilibrate by rapid solid state diffusional processes. These create a moving liquid interface which sweeps from the clad/core interface into the core of the material. This causes significant compositional changes in the volume through which the liquid film passes. Reduced brazeability (filler metal flow) results from the rapid diffusion of silicon into the core. Additionally, a coarse band of intermetallics is formed upon solidification of the enriched liquid zone which can impair corrosion resistance.

The phenomenon of liquid film migration (LFM) in aluminum brazing is described in a companion paper [1]. To clarify the mechanism, the effect of core alloy homogenization, cold work prior to brazing, and brazing temperature on the LFM kinetics has been studied. Based on microstructures, LFM kinetics, and concentration profile data, factors influencing the migration rate of liquid films have been analyzed. Several possible driving forces for LFM are proposed: (1) coherency strain energy, (2) reduction of particle/matrix interfacial energy, and (3) reduction of energy in recovered dislocation structure or subgrain boundaries in the case of lightly cold worked brazing sheet.

The nature and level of the vacuum atmosphere together with the depth and composition of the oxide layer on brazing sheet can have a profound effect on the quality of the brazed joint. For example, magnesium is needed in the furnace atmosphere to obtain a good fillet. However, there is a lack of understanding of the interrelationship between oxide thickness and the amount of magnesium in the furnace atmosphere. This paper attempts to address this area. Samples of brazing sheet with modified oxide layers, some of which simulate storage or transport conditions were brazed with varying magnesium content in the furnace atmosphere. A correlation was made between these two parameters and the material's brazeability. The main conclusion of this study was that if sufficient magnesium is present in the furnace atmosphere the material can tolerate significant changes in oxide thickness and type without sacrificing brazeability.

In the present paper it is shown that fatigue life prediction of a complex spot welded joint must take into account for damage evolution of each spot weld, thus considering the load changes in each spot during damage progression. A method which uses a theoretical stress solution (ERS) is presented and its application is reported both on traditional spot welded joints and on a non trivial joint. Through the use of ERS-N curves the fatigue data performed on different joint geometries can be successfully reconciled.

A theoretical model is developed for crushing of honeycomb structures. Axial crushing is considered for both adhesive bonded and welded honeycombs. The two mentioned cases present different kinematics of collapse; consequently, the Mean Crushing Strength assumes different values. The theoretical model discussed is also able to predict Bar Compressive Strength which is a fundamental variable to be taken into account in the design of energy absorbers for the automotive industry. The analytical results are successfully compared with experimental literature data and numerical results.

Robustness encompasses every aspect of the way in which a 2K (two-part) structural automotive adhesive is made and used, from manufacturing and storage to dispensability, adaptability to different substrates and stamping lubricants, cure characteristics, strength, and durability. Illustration of the many facets of adhesive robustness are made using primarily 3M #5047, a 2K epoxy hem flange adhesive developed for bonding oily untreated metals. Areas of robustness covered include storage stability, surface oil accommodation, open time, and performance under various curing conditions. The recent introduction of adhesives having unique mix ratio control and NDT capabilities heralds new levels of adhesive robustness.

Global manufacturing has the individual automotive component plants, on virtually all continents, scrambling for the “edge” to be the most competitive manufacturer and thus be the producer of choice. To be competitive in price and quality and that over “the long haul” is a tall order, indeed. A lot depends on the machining processes producing the components that, assembled, make up the powertrain. While outsourcing other automotive parts might be the right economical and technological choice, to produce ones own engines and transmissions is still one of the areas of true “value adding” and also a matter of the manufacturer's image. Hence the industry's effort to offer ever better, more potent families of engines and transmissions. New, advanced machining processes have evolved recently, that make manufacturing more productive and predictable. The three areas most promising are: One-pass finish-machining High-speed machining (Near) Dry-machining

The use of vibro-acoustics measurements during manufacturing testing as an approach for detecting defects has been steadily gaining acceptance in the automotive industry. Several studies performed by Hughes and others have demonstrated that signature analysis of vibro-acoustic spectra can be a sensitive measure of product quality. However, the implementation of a vibro-acoustic test system in a production environment is not always straightforward. Additionally, test system implementation and support requires knowledge in instrumentation, signal processing, spectral analysis, and statistical analysis. The latter skill is especially important in the development and maintenance of templates that provide pass/fail criteria. Template generation has been recognized as an engineering intensive process. This article discusses an approach to developing a robust vibro-acoustic manufacturing test, issues typically encountered, and some selected case studies.

The challenge was to have small, machined fuel-control components with cross-holes absolutely burr-free; to the extent that any loose particulate would cause the final assembly to fail. Parts are produced on multi-station Rotary Transfer Machining Centers and must be deburred at the rate of 3,600 per hour. Electro Chemical Deburring (ECD) was chosen because of its ability to selectively deburr features while leaving critical sealing surfaces untouched. The goal was to automate the ECD process to achieve maximum efficiency with minimum operator input, while maintaining extremely close control.

The purpose of this paper is to outline a new approach for production outsourcing of complex cast metal parts. The paper details the steps in providing a smooth transition from a CAD file through production. The key to this transition is the successful creation of the production tooling on the first attempt. Significantly shortened lead times and proper implementation of concurrent engineering are the consequent results. The inability to produce production tooling (patterns and core boxes) prior to creating a first article part is the main weakness of traditional casting processes. Creating production tooling is an expensive process that requires long lead times. The foundry, in order to minimize its financial risk, seeks to avoid total fiscal responsibility for the many required steps in converting a CAD design into serial production, and therefore charges the customer accordingly.

Manufacturing problems frequently originate years earlier in new product development. Examples include products that are hard to build or don't fit the production process; too many or too few products; unprofitable products that consume a disproportionate share of overhead; and products that were simply too late for their markets. The problem is well understood; the difficulty is knowing what to do about it, and how to make effective changes that the entire organization will support. This paper presents a comprehensive yet practical approach to improving the new product development process. The emphasis is on an integrated approach that leads naturally to implementation of the improved process throughout the organization. The approach is to recognize that effective product development spans three dimensions: the process, the technology, and the organization.

This paper describes the development and validation of a Lagrangian-based finite element model for the aluminum extrusion process used to produce thin sections which are characteristic of tubing used in automotive air conditioners. Due to the large reduction involved in producing such tubing, extrusion ratios are between 500 and 2000. In order to study metal flow and establish baseline strains and strain rates in the process, a finite element model based on non-isothermal plane strain deformation was developed. Effective strain rates were predicted to be as high as 1500 s-1 in the weld chamber with effective strains reaching 4.0 in each wall. Billet cooling on the order of 20 °C occurs in the container and portholes of the die while significant adiabatic heating occurs as a result of deformation in the weld chamber.

As a process that enables the high-speed and continuous forming of lengthy materials with a constant cross-sectional configuration, roll forming offers much higher productivity than the stamping process. However, in case a change must be made to the shape of the cross section, the material must normally be stamped or joined with a part containing a separate shape. This affects productivity, increases the number of pieces, and degrades the material's appearance. This report describes the roll-forming technology that we developed, in which the cross section of the material can be changed gradually. This method adopts a system which uses a movable and rotatable roll-stand that enables high-speed, continuous roll-forming processes.