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A task group within the SAE Automotive Corrosion and Protection (ACAP) Committee continues to pursue the goal of establishing a standard test method for in-laboratory cosmetic corrosion evaluations of finished aluminum auto body panels. The program is a cooperative effort with OEM, supplier, and consultant participation and is supported in part by USAMP (AMD 309) and the U.S. Department of Energy. Numerous laboratory corrosion test environments have been used to evaluate the performance of painted aluminum closure panels, but correlations between laboratory test results and in-service performance have not been established. The primary objective of this project is to identify an accelerated laboratory test method that correlates with in-service performance. In this paper the type, extent, and chemical nature of cosmetic corrosion observed in the on-vehicle exposures are compared with those from some of the commonly used laboratory tests

In developing the features of a spark-ignition combustion chamber, optical combustion diagnostic technology was employed to understand the factors contributing to knock propensity of the combustion system. This optical combustion visualization equipment utilizes optical prisms located around the periphery of the spark plug shell to measure light intensity of combustion. By synchronizing light intensity and cylinder pressure measurements to crankshaft position, local tracking of combustion progression is accomplished. This method was used to track knock occurrences and to evaluate their controlling parameters within this combustion system. Cylinder head and piston top geometries were developed as a result of this combustion visualization. Recommendations derived from these studies were successfully used to achieve objectives of this engine development program which included improvements in torque and power output, fuel economy, and combustion stability.

The ability to predict the interior acoustic sound field in a vehicle is important in order to avoid or to minimize unwanted noise conditions, such as boom or high pressure levels at cavity resonance frequencies. In this work an acoustic modal analysis is carried out for a minivan. The testing procedure is discussed and some results are shown. With the seats removed and for low frequencies the interior of the vehicle is similar to a rectangular box for which an analytical solution exists. At higher frequencies and with the seat, the interior acoustic field displays complex mode shapes.

The Milliken Moment Method (MMM) can be used to quantify the constraints imposed on vehicle stability and controllability by front and rear tire traction limitations. The main aspect of the Milliken Moment Method is the plot of vehicle's yaw moment versus lateral acceleration for given vehicle sideslip and steering angle ranges. This plot is typically called the Milliken Moment Diagram (MMD). This paper proposes a dynamic simulation approach to implementing the MMM that emulates the traditional experimental one. The approach embeds a vehicle dynamics model in a control loop that maintains a constant desired sideslip angle, and integrates the resulting controlled vehicle system model in time to generate the MMD.

Improving the performance characteristics of a typical disc brake encompasses a number of design strategies as well as limitations imposed by cost objectives. Utilizing pad loading uniformity in a design is one strategy that offers an improvement in desired performance characteristics, including a reduction in tapered lining wear as well as a possible reduced propensity for noise generation. To approach this design strategy, a procedure has been developed to tailor the brake pad lining profile to maximize pad loading uniformity in a multibody dynamics model of a typical disc brake. In determining an optimal lining configuration, a suitable compromise for gaining beneficial performance improvements in a cost effective manner is reached. The implementation of this design strategy involves the parametric definition of the lining profile by introducing a series of variables that are linked to the profile markers.

Avoiding low-frequency pressure pulsations and establishing a good axial static pressure distribution are primary concerns for open jet wind tunnels. The current research was conducted to ensure the full scale Chrysler Aero-Acoustic Wind Tunnel (AAWT) design is consistent with good performance in these two areas. Experiments were conducted in two tunnels: a 1/3.6-scale closed-circuit tunnel and a 1/12-scale open-loop tunnel. Results from both are consistent, and a configuration that exhibits i) minimal pulsations for both empty test section and 15% vehicle blockage and ii) a good axial static pressure distribution has been identified for the AAWT. The results illustrate the effect of open jet length, collector geometry, and plenum geometry on pulsation levels and highlight the spatial variation of the pulsation levels within the plenum chamber. Pulsation levels were observed to increase with increasing open jet length and decreasing collector throat area.

Adhesive joining is a common autobody subassembly technique especially for outer panels, where visible spot welding is objectionable. To accommodate mass production with the use of certain adhesives very high thermal gradient usually exists, which may result in panel dimensional distortion and variation. The temperature distribution over location and over time are monitored, and its impact to panel dimension is investigated. Experimental results on the effect of the distance between panel and induction coil on the panel temperature is obtained. The thermal induced shape distortion is simulated with a simplified FEA model. The approach to improvement of the induction curing process is discussed.

In this paper, an analytical method is proposed for determining the stress distributions in steering knuckle/tapered stud assemblies. The method is based on solutions of the plane stress thick cylinder interference fit problem with modifications to account for the effects of stud taper and dissimilar component materials. The analytical solutions are applied to knuckle/tapered stud assemblies. The results from the analytical solutions are compared to those from a finite element analysis. It is shown that the analytical and FEA results are in good agreement for several load and frictional conditions, and the hoop and radial stress solutions presented in this paper are good engineering solutions to the knuckle/tapered stud problem where the draw distance is provided.

For the new 4.7 L, V-8 engine, which was introduced in the all new 1999 Jeep Grand Cherokee, Chrysler product engineers found they needed a bedplate material that was significantly stronger and stiffer than gray iron to help meet engine weight requirements. The material also had to provide good NVH characteristics, be cost effective, and machinable. Intermet Corporation, the casting supplier, wanted a material that was significantly tougher than gray iron, would cast sound in complex sections, and which could be reliably produced on a cost effective basis. This paper presents an overview of the development, properties, casting practices, and engine validation of enhanced compacted graphite iron, a material specifically developed and tailored for the bedplate of the new 4.7 liter engine.

This paper is a discussion on a statistical problem solving approach to determine the root cause of shimmy in a Chrysler Jeep® Cherokee. A blend of statistical approach with strong analytical quantification is used to give the problem solving a non-subjective flavor. The statistical aspect of the problem solving consists of DOE (Design of Experiments) while the analytical portion describes the instrumentation, data acquisition and analysis.

Chrysler began a limited development program directed toward a new automatic transmission fluid (ATF) early in 1989 and launched a full time effort in 1994. The development process for the new ATF involved a significant level of bench testing and eventually vehicle tests to evaluate the durability and shift quality of the ATF. The bench tests included those that pertain to oxidation and shear stability, anti-wear, frictional properties and torque converter shudder. Vehicle tests were primarily extended durability in both internal vehicle fleets and at external taxi sites. The mileage accumulated in this phase of the development program exceeded two million miles, all with no fluid drains out to 100,000 miles. Additionally, shift feel tests were conducted in Chrysler vehicles to verify compliance to targets. This paper summarizes the tests and results that lead to the development of the new Chrysler fill-for-life automatic transmission fluid.

As part of the International Lubricant Standardization and Approval Committee's (ILSAC) goal of developing a global automatic transmission fluid (ATF) specification, members have been evaluating test methods that are currently used by various automotive manufacturers for qualifying ATF for use in their respective transmissions. This report deals with comparing test methods used for determining torque capacity in friction systems (shifting clutches). Three test methods were compared, the Plate Friction Test from the General Motors DEXRON®-III Specification, the Friction Durability Test from the Ford MERCON® Specification, and the Japanese Automotive Manufacturers Association Friction Test - JASO Method 348-95. Eight different fluids were evaluated. Friction parameters used in the comparison were breakaway friction, dynamic friction torque at midpoint and the end of engagement, and the ratio of end torque to midpoint torque.

This paper presents one American vehicle manufacturer's perspective on global regulatory harmonization, which is critically required for the future development and well being of the vehicle global market. The paper provides a brief overview of the past and present harmonization efforts and discusses some of the impediments in achieving agreements among different rulemaking bodies. Despite the often hampered goal of total harmonization, the paper submits that progress can be achieved with the reciprocal acceptance of functionally equivalent standards and other stop-gap measures to curb the ever spiraling requirements. The paper concludes on an optimistic note by citing some of the recent developments that bring the harmonization frontier closer to becoming a reality.

This study was conducted to analyze and quantify the effects of accelerated weathering on the surface of various “weatherable” polymers currently utilized for molded-in-color exterior automotive applications. Evaluations consisted of gloss/color retention and surface changes after accelerated weathering exposure, with and without intermittent washing, to simulate product life cycle. Results were found to be affected by both polymer type and interim surface treatments. Data are presented as a means to define specific performance and aesthetic capabilities of these various polymers in a mold-in-color environment to optimize material selection for related component applications.

An assessment of Body-In-White quality and launch preparedness occurs at many intervals. This paper will focus on dimensional control activities that take place during the first pre-production pilot phase known as P0. (P-zero occurs approximately 35 weeks before volume production.) Two Process Assurance Body Build Systems (Tooling Build and Plate Build) have been used at Chrysler and the results have been documented. The Plate Build and Tooling Build activities provide the opportunity to uncover and resolve Product Design and Part Quality Issues. In addition, the Tooling Build process has proven to be an objective method of identifying and correcting tooling, gaging and process issues during the P0 Vehicle Build Program.

Multiplexing systems have been used in automobiles for the past decade. The use of these systems has allowed manufacturers to reduce wiring harness size, eliminate redundant sensors, and achieve a level of communication not available before. While most applications of multiplexing have been inter-modular communication, there exist many more opportunities to utilize multiplexing. These opportunities include multiplexing various user activated/interacted switches, sensors, and actuators. Multiplexing of this type is defined by the SAE as a low speed sensor/actuator bus, or Class “A” bus. The Class “A” bus addresses issues, such as: the challenge of handling increasing wiring complexity, incorporating diagnostics and testability into automotive electronic designs, facilitating the use of new switch and actuator technologies, and allowing a higher degree of systems design flexibility.

For decades the Automotive Industry has purchased emission test equipment to meet EPA requirements. Existing systems utilize gas analyzers that provide analog outputs to computers or programmable controllers that, in turn, digitize the signals and communicate them to the cell computer. These systems use complex computer hardware and software systems to collect more than 25 channels of analog signals, convert them to digital, and report them. This architecture is very difficult to maintain and requires excessive effort to modify. The systems do not have any provisions for self-diagnostics or control charting. In 1996 Quantum Controls, Inc. and Chrysler Corporation, Chelsea Proving Grounds began work on the next generation emission test cell. The design goals were: Speed of response to be maximized. The time to digitize the signal and communicate it to the cell computer for all analyzers in a bench must be at least 20Hz with a goal of 30Hz.

Life cycle benefits of a chrome-free sealing wash were evaluated. Material consumption, disposal costs, water pretreatment, waste water treatment and product performance were used to compare a chrome-free product to traditional washes. Acquisition costs and vehicle weight impacts were also considered. The direction of domestic and international regulatory initiatives will play a significant part in the application of this study=s findings. The paper discusses the factors and decision process that led to the trial of chrome free rinse in a vehicle assembly plant and the results of this test. Durability testing was performed with current and evolving primer systems. Equivalent durability was shown with multiple supplier/multiple primer process combinations. The study indicated that chrome-free sealing wash would yield a small cost savings and a minor reduction in weight with equal performance to the current chrome containing process.

Hand dismantling of end of life vehicles (ELV) may have limited use on recovering the majority of materials that will be in our future automobiles. Research is being conducted on automated methods to recover pure plastics from automotive shredder residue (ASR). As part of USCAR initiative, the Vehicle Recycling Partnership (VRP), a cooperative effort among Chrysler, Ford and General Motors undertook a study to determine the feasibility of obtaining pure plastics from ASR using density and skin flotation separation technologies. The total project concept is described in this paper including important elements such as the detailed dismantling of a baseline vehicle to define total plastics complexity, shredding vehicles, collecting ASR samples and performing R&D work on automated recovery methodologies.

This paper presents a crankshaft speed fluctuation model based dynamic neural network misfire detection method to achieve high detection performance and compact network size. In this method, a dynamic neural network with output feedback is utilized to model an inverse system from the engine crankshaft speed signal to the firing event signal. The engine misfire detection is based on the output of the inverse system given the input of engine speed signal. Test results for a 4-cylinder engine show its promising capability of misfire detection even for the low sampling rate data under various engine operating conditions and misfire patterns.