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Technical Paper

Effects of Fuel Volatility, Load, and Speed on HC Emissions Due to Piston Wetting

Piston wetting can be isolated from the other sources of HC emissions from DISI engines by operating the engine predominantly on a gaseous fuel and using an injector probe to impact a small amount of liquid fuel on the piston top. This results in a marked increase in HC emissions. In a previous study, we used a variety of pure liquid hydrocarbon fuels to examine the influence of fuel volatility and structure on the HC emissions due to piston wetting. It was shown that the HC emissions correspond to the Leidenfrost effect: fuels with very low boiling points yield high HCs and those with a boiling point near or above the piston temperature produce much lower HCs. All of these prior tests of fuel effects were performed at a single operating condition: the Ford World Wide Mapping Point (WWMP). In the present study, the effects of load and engine speed are examined.
Technical Paper

Oxidation Stability of Automatic Transmission Fluids -A Study by the International Lubricants Standardization and Approval Committee (ILSAC) ATF Subcommittee

The International Lubricant Standardization and Approval Committee (ILSAC) ATF subcommittee members have compared the two oxidation bench test methods, Aluminum Beaker Oxidation Test (ABOT) and Indiana Stirring Oxidation Stability Test (ISOT), using a number of factory-fill and service-fill ATFs obtained in Japan and in the US. In many cases, the ATFs were more severely oxidized after the ABOT procedure than after the same duration of the ISOT procedure. The relative severity of these two tests was influenced by the composition of the ATFs. The bench test oxidation data were compared with the transmission and the vehicle oxidation test data.
Technical Paper

The Aluminum Beaker Oxidation Test for MERCON™ World-Wide Service ATF

The Aluminum Beaker Oxidation Test is one of the tests specified for MERCONtm service ATF. The test is now being run at independent laboratories. Passing this and other specified tests is part of the process required to obtain a licence to describe an ATF as MERCONtm. The performance of test facilities at independent laboratories has been monitored by evaluating test data obtained with reference ATFs provided by Ford. The data so obtained, together with data obtained at Ford and other laboratories, have been used to generate a statistically significant data base. This data base has been used to better define test repeatability and reproducibility and thus provide an improved basis for monitoring the performance of test facilities. This paper provides a summary of the test procedure, reviews the data supporting the validity of the test, and presents information on the repeatability and reproducibility of the test method.
Technical Paper

The Relative Effect of Paint Film Thickness on Bimetallic and Crevice Corrosion

The proliferation of Unibody construction, for vehicle weight reduction, and the expanded use of precoated steel, for improvement in outer body rust-through protection, has significantly increased the number of bimetallic and crevice unions on U.S. manufactured vehicles. Cyclic corrosion and proving ground testing has shown that these unions are highly active electrochemically, resulting in extensive anodic corrosion and cathodic de-lamination of the paint film. This work examines the individual contribution of each layer of the applied protective coatings package, with respect to applied film thickness, to the reduction of permeation by water, oxygen, and NaCl and resultant corrosion.
Technical Paper

Breaking Load Method Evaluation of Sheet AA7075

Increasing fuel economy is a high priority of the automotive industry due to consumer demand and government regulations. High strength aluminum alloys such as AA7075-T6 can be used in strength-critical automotive applications to reduce vehicle weight and thus improve fuel economy. However, these aluminum alloys are known to be susceptible to stress corrosion cracking (SCC) for thick plate. The level of susceptibility to SCC must be determined before a material is implemented. ASTM standards exist that generate semi-quantitative data primarily for use in screening materials for SCC. For the purposes of this work ASTM G139 (breaking load method) has been used to evaluate sheet AA7075-T6 for use in automotive applications. A tensile fixture applying a constant strain was used to quantitatively measure residual strength of the material after exposure to a corrosive environment.
Technical Paper

A Rapid Screening Test to Assess Relative Corrosion Performance of Automotive Condensers

A simple and rapid immersion type corrosion test has been successfully developed that discriminates corrosion performance in condensers from various suppliers and with differing manufacturing processes. The goal is to develop a test specification that will be included in the Ford corrosion specification for condensers so that condensers received from various suppliers may be evaluated rapidly for their relative corrosion performance to each other. Sections from condensers from Supplier A (tube is silfluxed), Supplier B (tube is zinc arc sprayed), and Supplier C (bare folded tube with no zinc for corrosion protection) were tested in 2% v/v hydrochloric acid for 16, 24 and 48 hours. The results showed that in terms of corrosion performance, zinc arc sprayed Supplier B condenser performed the worst while Supplier C condenser performed the best with Supplier A in between. It was also observed that the fins, and fin-to-tube joints were first to corrode followed by the tube in all cases.
Technical Paper

Accelerated Corrosion Testing of Automotive Evaporators and Condensers

There is an ongoing effort in the industry to develop an accelerated corrosion test for automotive heat exchangers. This has become even more important as automakers are focusing on corrosion durability of 15 years in the field versus current target of 10 years. To this end an acid immersion test was developed and reported in a previous paper for condensers (1). This paper extends those results to evaporators and establishes the efficacy of the test using these results and those reported in the literature. The paper also discusses variability in corrosion test results as observed in tests such as ASTM G85:A3 Acidified Synthetic Sea Water Test (SWAAT), and its relation to field durability.
Technical Paper

Improved P/M Stainless Steel Exhaust Flanges Based on Innovative Design Concepts

Powder metal (P/M) stainless steel exhaust flanges have been qualified for a number of passenger cars and trucks in recent years. These flanges are currently being produced in high volumes to supply those vehicles. The requirements for these applications will continue to change over time as federal and state governmental mandates for improved emissions become effective. Lower leak rate limits, higher engine operating temperatures, and extended service life for components, are among the consequences of the search for improved emissions. The P/M process offers a high degree of flexibility with product design and related materials development, thus being able to meet these challenges. P/M stainless steel exhaust flanges' performance can be enhanced by 1. optimal design using finite element analysis and 2. modifying alloy compositions to improve strength.
Technical Paper

Aqueous Corrosion of Experimental Creep-Resistant Magnesium Alloys

This paper presents a comparison of aqueous corrosion rates in 5% NaCl solution for eight experimental creep-resistant magnesium alloys considered for automotive powertrain applications, as well as three reference alloys (pure magnesium, AM50B and AZ91D). The corrosion rates were measured using the techniques of titration, weight loss, hydrogen evolution, and DC polarization. The corrosion rates measured by these techniques are compared with each other as well as with those obtained with salt-spray testing using ASTM B117. The advantages and disadvantages of the various corrosion measurement techniques are discussed.
Technical Paper

Faster is Better: The Effect of Internal Turbulence on DOC Efficiency

A number of metallic oxidation catalyst substrates with advanced internal structures have emerged in the past few years. In an aftertreatment application, these structures improve gas mixing by increasing turbulence within the substrate's matrix. Modeling results show these advanced structures, under some operating conditions, can be correlated to reductions in catalyst substrate volume and precious metal 1,2. Three structured metallics were compared to a baseline ceramic substrate in a designed experiment to understand the effect of advanced metallic substrates on diesel oxidation catalyst (DOC) sizing and performance. The results showed that smaller metallic DOCs coated with up to 30% less precious metal (PM) catalyst performed on par or better than the baseline ceramic DOC in terms of hydrocarbon conversion, heat-up, and pressure drop.
Technical Paper

Method Development for Evaluating Microbiological Growth on and Attachment to Aluminum Air Conditioner Evaporator Core Surfaces

Corrosion failures of aluminum air conditioner evaporator cores have been reported in regions where the climate is relatively warm and humid. Microbiologically-influenced corrosion [MIC] has been implicated in these failures. Application of surface-treatment chemicals may inhibit microbiological (bacterial) growth and/or attachment, thereby reducing the potential for MIC. In this study, two laboratory methods were developed to evaluate selected surface-treatment chemicals for their ability to inhibit bacterial growth and reduce bacterial attachment to treated surfaces. Using the developed methods, two controlled-atmosphere brazed aluminum core materials and three surface-treatment chemicals were evaluated. Neither of the untreated core materials was found to inhibit the growth of the bacteria tested.
Technical Paper

Oil Migration on Sheet Steels and the Effect on Performance in Metal Stamping

Mill oils and prelubes are applied by the steel producer to prevent corrosion and to enhance formability. During coiling, shipping, and storage the lubricant migrates due to pressure and gravity. The redistribution of the lubricant results in widely varying lubricant weights. The move to reduce and eliminate press-applied lubricants has lead to concerns that the variation in lubricant weight as a result of this migration would adversely affect press performance. The Drawbead Simulator (DBS) and Twist Compression Test (TCT) were used to evaluate friction response of electrogalvanized and galvanneal sheet to varying lubricant weight. Results showed the electrogalvanized sheet was sensitive to lubricant type while the galvanneal sheet was sensitive to the amount of lubricant.
Technical Paper

Selective Galvanizing Using Kinetic Spraying

General corrosion protection of sheet materials such as steel used in automobile construction has reached a high level of performance, due primarily to the incorporation of mill-applied treatments such as electrogalvanizing, galvannealing and other coil-coating processes developed over the last half century. While such treatments have greatly extended the corrosion resistance of steel and its various body constructs, attention is now focused on aspects of the manufacturing process wherein these intended protections are compromised by such features as weldments, joins, cut edges and extreme metal deformations such as hems. A novel metal deposition process, based on high-velocity impact fusion of solid metal particles, has been used to extend the corrosion resistance of base steel and pre-galvanized sheet, by selectively placing highly controlled depositions of zinc and other sacrificial materials in close proximity to critical manufacturing details.
Technical Paper

Update on the Developments of the SAE J2334 Laboratory Cyclic Corrosion Test

The Corrosion Task Force of the Automotive/Steel Partnership has developed the SAE J2334 cyclic laboratory test for evaluating the cosmetic corrosion resistance of auto body steel sheet. [Ref. 1] Since the publishing of this test in 1997, further work has improved the precision of J2334. In this paper, the results of this work along with the revisions to the J2334 test will be discussed.
Technical Paper

An Obliquely Incident X-Ray Radiography to Measure Greatest Corrosion Depths in Automobile Metallic Plates

An obliquely incident X-ray radiography was developed to measure the greatest depths, orientations and locations of corrosion pits in automobile metallic plates. This technique can also be used on-site for components in use. The corrosion depth profile and the greatest depth can be calculated with the established relations. A 3-D rotational microscope and surface profiler were utilized to evaluate the sensitivities and accuracies of the technique for aluminum and steel plates, respectively.
Technical Paper

Effects of Engine Oil Formulation Variables on Exhaust Emissions in Taxi Fleet Service

The relationship between engine oil formulations and catalyst performance was investigated by comparatively testing five engine oils. In addition to one baseline production oil with a calcium plus magnesium detergent system, the remaining four oils were specifically formulated with different additive combinations including: one worst case with no detergent and production level zinc dialkyldithiophosphate (ZDTP), one with calcium-only detergent and two best cases with zero phosphorus. Emissions performance, phosphorus loss from the engine oil, phosphorus-capture on the catalyst and engine wear were evaluated after accumulating 100,000 miles of taxi service in twenty vehicles. The intent of this comparative study was to identify relative trends.
Technical Paper

Residual Stresses in Cup Drawing of Automotive Alloys

Residual stresses in metals are caused by a number of processes such as inhomogeneous deformation, phase changes and temperature gradients. This investigation focuses on the residual stresses caused by plastic deformation of automotive metals. Such stresses are responsible for part springback and shape distortion in many manufacturing and assembly processes. Tensile residual stresses may lead to stress cracking and, in some alloys, to stress corrosion cracking which may ultimately lead to premature product failure. The residual stress potential of metals can be evaluated by using the Split Ring Test Method. The test can be used to evaluate the effect of materials on residual stresses in cup drawing. Drawn cups are used because they produce large amounts of residual stresses and, therefore, increase measurement accuracy and reduce experimental error. A closed form analytical solution is used to estimate residual stresses in split rings taken from sections cut from the drawn cups.
Technical Paper

2005 Fuel Cell Vehicle and its Magnesium Power Distribution Unit

The High Voltage Power Distribution Unit (PDU) is constructed of magnesium in support of Fuel Cell Electric Vehicle (FCEV) weight reduction efforts. The PDU distributes and controls a nominal 75 kilowatts of power generated by the Fuel Cell, the primary source of High Voltage power, to all the vehicle loads and accessories. The constraints imposed on the design of the PDU resulted in a component highly susceptible to general and galvanic corrosion. Corrosion abatement was the focus of the PDU redesign. This paper describes the redesign efforts undertaken by Ford personnel to improve the part robustness and corrosion resistance.
Technical Paper

Managing Thermal Growth for Large Class “A” Polymer Body Panel Closure Systems

The history behind Polymer Class “A” Body Panels for automotive applications is very interesting. The driving factors behind these applications have not changed significantly over the past sixty years. Foremost among these factors is the need for corrosion and dent resistance. Beginning with Saturn in 1990, interest in polymer body panels grew and continues to grow up to the present day, with every new global application. Today, consumers and economic factors drive the industry trend towards plastic body panels. These include increased customization and fuel economy on the consumer side. Economic factors such as lower unit build quantities, reduced vehicle mass, investment cost, and tooling lead times influence material choice for industry. The highest possible performance, and fuel economy, at the lowest price have always been a goal.