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The increasing use of diesel and gasoline particulate filters requires advanced on-board diagnostics (OBD) to prevent and detect filter failures and malfunctions. Early detection of upstream (engine-out) malfunctions is paramount to preventing irreversible damage to downstream aftertreatment system components. Such early detection can mitigate the failure of the particulate filter resulting in the escape of emissions exceeding permissible limits and extend the component life. However, despite best efforts at early detection and filter failure prevention, the OBD system must also be able to detect filter failures when they occur. In this study, radio frequency (RF) sensors were used to directly monitor the particulate filter state of health for both gasoline particulate filter (GPF) and diesel particulate filter (DPF) applications.

The primary objective in design is to achieve the target value of the design's response function. If a design fails to achieve the target value, it most likely fails in two ways: inconsistent functional output and in design involving multiple response functions, unable to converge to the multiple target values in spite of iterative adjustment of the design parameters. The former is symptom of a design not able to perform in the presence of variability, i.e., noise. The latter is symptom of a design that fails to perform in the presence of functional coupling. Both problems are best addressed at the conceptual stage of the design at which only design solution that is inherently robust to noise and functionally uncoupled is entertained. If this is not possible, the alternative is to exploit the interaction between control variables and variables that are sources of noise and functional coupling to render the design insensitive to them.

Design analysts, who work with finite element shape optimization, face a daunting task of handling cylindrical parts like a pusher for a crimp. The shape vectors generated by any of the existing methods/tools cannot constrain nodes to move in a circular path. Since the pusher is not a complete cylinder and the loading is only along axial direction, shape optimization was performed after flattening out the cylindrical pusher. The existing shape optimization tools could now be applied to the flat plate. A numerical interpolation method, based on ‘Autodv’, has been used to generate shape vectors. Both weight and stresses have been brought down and the final design was verified with solid finite element analysis.

In the present study, the NVH performance of an engine valve cover assembly is analyzed by the use of “spatial transmissibility (TR)”. It is a measure of the spatial response of the cover relative to the spatial response of the underlying structure to which it is connected. A prototyped engine valve cover assembly is examined. The cover transmissibility is computed through the finite element method and also measured by experimental testing. Various isolation systems have been examined and different cover materials have been investigated, including magnesium and thermosetting plastic. The transmissibility provides a strategy for evaluating the NVH characteristic of engine cover assembly in a much more timely, cost-effective manner, while the product is still in the early conceptual stage.

The powertrain engine is a major source of vibration and noise in automotive vehicles. Among the powertrain components, the valve cover has been identified as one of the main noise contributors due to its large radiating surface and thin shell-like structure. There has been an increasing demand for rapid assessment of the valve cover noise level in the early product design stages. The present study analyzes the radiated sound pressure level (SPL) of a valve cover assembly using the finite element method (FEM). The analysis is first performed using a fully coupled structural-acoustic approach. In this case the solid structure is directly coupled to the enclosed and surrounding air in a single analysis, and the structural and acoustic fields are solved simultaneously. In the next approach, the analysis is performed in a sequential manner, using a submodeling technique. First, the structural vibration of the cover is analyzed in the absence of the surrounding air.

The combustion process after auto-ignition is investigated. Depending on the non-uniformity of the end gas, auto-ignition could initiate a flame, produce pressure waves that excite the engine structure (acoustic knock), or result in detonation (normal or developing). For the “acoustic knock” mode, a knock intensity (KI) is defined as the pressure oscillation amplitude. The KI values over different cycles under a fixed operating condition are observed to have a log-normal distribution. When the operating condition is changed (over different values of λ, EGR, and spark timing), the mean (μ) of log (KI/GIMEP) decreases linearly with the correlation-based ignition delay calculated using the knock-point end gas condition of the mean cycle. The standard deviation σ of log(KI/GIMEP) is approximately a constant, at 0.63. The values of μ and σ thus allow a statistical description of knock from the deterministic calculation of the ignition delay using the mean cycle properties

In this paper we investigate the optimal forming of conical cups of AL 2008-T4 through the use of real-time process control. We consider a flat, frictional binder the force of which can be determined precisely through closed-loop control. Initially the force is held constant throughout the forming of the cup, and various levels of force are tested experimentally and with numerical simulation. Excellent agreement between experiment and simulation is observed. The effects of binder force on cup shape, thickness distribution, failure mode and cup failure height are investigated, and an “optimal” constant binder force is determined. For this optimal case, the corresponding punch force is recorded as a function of punch displacement and is used in subsequent closed-loop control experiments. In addition to the constant force test, a trial variable binder force test was performed to extend the failure height beyond that obtained using the “optimal” constant force level.

Draw beads are widely utilized as a mechanism for providing proper restraining force to a sheet in a forming operation. In this paper, numerical simulations using the nonlinear finite element method are conducted to model the process of drawing a sheet through various draw bead configurations to study the mechanics of draw bead restraint. By examing the sensitivity of the draw bead restraining force due to the change of the draw bead penetration, the work shows that the penetration has the potential to be a very good element for varying and controlling restraining force during the process. A closed-loop feedback control of draw bead penetration using a proportional-integral controller is achieved by the combination of the original finite element simulation and a special element which links penetration to a pre-defined restraining force trajectory.

The intent of this paper will be to address the level of performance and cost of the various complex instruction set computers (CISC-80X86) versus the reduced instruction set computers (RISC). The original concept of reduced instruction set computers will be explained. The above information will be contrasted with how the second generation system functions. Once the operations are established, a discussion of operating performance as related to several types of benchmarks will be cited. A typical FEA model will be used as the final benchmark to determine realistic performance versus speed (wall clock time). The final comparison will be of cost.

A major concern in head gasket reliability of an industrial diesel engine is flange cracking. This paper will discuss head gasket flange cracking and the head gasket joint environment as they relate to an industrial diesel engine head gasket joint. The paper will discuss metallographic and finite element analysis of head gasket field failures. The metallographic analysis will discuss the evaluation of production, assembled, laboratory tested, and field tested gaskets. The above will give head gasket designers and engine manufacturers insight into the industrial head gasket joint environment. The metallographic work will explain the method of creating micro sections as well as micro section measurements to aid in the understanding of the head gasket loading.

New analysis methods have been developed which allow heavy duty diesel engine cylinder head to block joints to be studied in a more effective manner. Failure analysis can yield more meaningful, quantitative results through the use of X-rays and microhardness measurements. Experimental methods of determining direction and magnitude of thermal motion, interactions between cylinder pressure and thermal cycling, and the relationship between leak pressure and thermal condition have been developed. Deep thermal cycle dynamometer testing has also been used successfully to duplicate failure modes seen in the field.

The design objective of the Spicer S400-S axle program was to develop a light weight, lower torsional vibration, long life tandem drive axle for the heavy truck industry. This was accomplished with the incorporation of a number of new product features and technical advancements, both in design and manufacturing. These include: reduced standouts for improved interaxle driveline angles use of finite element analysis fixed pinion mounting optimization of lube flow and direction of lubrication optimized gear design for improved strength and noise reduction. This paper focuses on these features and also on the development process for the axle, including the use of simultaneous engineering. Utilizing simultaneous engineering, the S400-S was developed from concept to full production in fifteen months.

This paper will discuss metallurgical failure analysis of microwelded iron piston rings and aluminum pistons in internal combustion engines. “Microwelding” is defined as adherence of sporadic particles of aluminum from the piston to the bottom side of the piston ring. The paper will describe the high output water-cooled two-stroke engine accelerated test which reproduces the microwelding phenomenon in 30 minutes. SEM and EDS analyses have been used in the identification of the mechanism of this surface damage. Evidence of extreme temperatures during pre-ignition and normal operating conditions was obtained by studying hardness distributions through the piston cross section. As a potential solution, decreasing temperature through use of a thermal barrier coating was investigated. Also, test results of piston ring coatings, including molybdenum and tungsten disulfide, electroplated chromium, PVD titanium and chromium nitride, and fluoroplastic materials were compared.

The engine valve cover is known to be major contributor to powertrain noise due to its large surface area and relatively small thickness. Thus, the acoustic analysis of the valve cover has become one of the key steps in the design process. The present paper describes an acoustic infinite element approach to model the sound radiation of the valve cover. The valve cover bolted to the engine block behaves like a vibrating membrane in an acoustic medium of infinite extent. Typically, the effect of the infinite medium is modeled using either the boundary element method (BEM), or by specifying an equivalent boundary impedance on the terminating surface of an acoustic finite element mesh (NRBC). In this paper, a third method is introduced, wherein the boundary impedances are replaced by acoustic infinite elements. The methodology is presented using two different models. In the first model, a cover with a geometrically simple shape is analyzed.

The transmissibility technique has been traditionally used for evaluating the NVH performance of isolated, rigid structures such as the elastomer mount isolated automobile engine. The transmissibility quantity provides information on how a structure reduces vibration as subjected to dynamic loading and thereby attenuates noise. In the present study, the transmissibility is applied to a non-rigid, plastic structure - the engine cylinder-head cover module. The cover module includes primarily a thin, plate-like cover and the elastomer isolation system. At low frequencies, the cover will behave as a rigid mass and thus display a major peak at its resonant frequency. At high frequencies, the cover will vibrate as a flexible panel and thus display multiple peaks with magnitudes differing from point to point across the cover surface. As a result, the transmissibility calculated would have a spatial resolution, called the spatial transmissibility.

EQUIPMENT for measuring vibration in airplane structures and powerplants during actual flight is described in this paper. This development is the result of a cooperative research program carried out by the Bureau of Aeronautics of the U. S. Navy and the Massachusetts Institute of Technology with contributions of improvements in design and new features by the Sperry Gyroscope Co., Inc. In its essentials, the M.I.T.-Sperry Apparatus consists of a number of electrical pickup units which operate a central amplifying and recording unit. The recorder is a double-element photographic oscillograph. Each pickup is adapted especially to the type of vibration that it is intended to measure and is made so small that it does not appreciably affect the vibration characteristics of the member to which it is attached rigidly. By using a number of systematically placed pickups, all the necessary vibration information on an airplane can be recorded during a few short flights.

ON THE basis of laboratory and field tests of passenger-car and light-truck rear axles, the authors conclude: 1. The capacity of present axles can be increased, without increasing axle size, when greater load-carrying antiwear and antiscore lubricants are available. 2. Gear noise will always be a major problem because axle gears are operating at varying speeds and loads whenever a car is in motion. Many gear noise problems can be overcome by proper tooth development and by testing in the actual car model under which the axle will be used. 3. The only reliable basis for torque-capacity rating is the tractive effort (wheel-slip torque). 4. The limited-slip type of differential will eventually become standard equipment on all passenger cars, if only to improve car handling and stability during high-speed driving under varying traction conditions.

THE INCREASED use of midship-mounted transmissions in large equipment has emphasized the need for a torsionally resilient connection from the engine to reduce vibration transfer. To increase the torsional flexibility needed in these systems, the spring rate of the system must be reduced by such constructions as a flexible coupling, a spring-loaded damper, or a rubber torsional spring. This paper discusses these systems, emphasizing rubber springs. Some advantages of such a drive are: it provides an amplitude limitation with impact loads and a cushion to reduce noise and prevent clattering and contacts noises on parts with backlash, it smooths out transition periods to reduce loads on bearings and gears, its clamping characteristics can be adjusted by various rubbers, and its rubber cushion provides a degree axial flexibility.*

A simple and basic laboratory test is described which may be used to evaluate and compare axle noises in a passenger car. In this method, a number is assigned to the magnitude of a given noise at any given frequency through a complete range of speed and load conditions during typical vehicle operation. A chassis dynamometer is used to simulate road conditions, and various pickup and recording instrumentation are employed to record the objectionable noises under different operating conditions and speeds.

One of the goals of designing engineering systems is to maximize the system's reliability. A reliable system must satisfy its functional requirements without failure throughout its intended lifecycle. The typical means to achieve a desirable level of reliability is through preventive maintenance of a system; however, this involves cost. A more fundamental approach to the problem is to maximize the system's reliability by preventing failures from occurring. A key question is to find mechanisms (and the means to implement them into a system) that will prevent its system range from going out of the design range. Functional periodicity is a means to achieve this goal. Three examples are discussed to illustrate the concept. In the new electrical connector design, it is the geometric functional periodicity provided by the woven wire structure. In the case of integrated manufacturing systems, it is the periodicity in scheduling of the robot motion.