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An experimental study is performed to investigate the effects of charge motion control on in-cylinder fuel-air mixture preparation and combustion inside a direct-injection spark-ignition engine with optical access to the cylinder. High-pressure production injector is used with fuel pressures of 5 and 10 MPa. Three different geometries of charge motion control (CMC) device are considered; two are expected to enhance the swirl motion inside the engine cylinder whereas the third one is expected to enhance the tumble motion. Experiments are performed at 1500 rpm engine speed with the variation in fuel injection timing, fuel pressure and the number of injections. It is found that swirl-type CMC devices significantly enhance the fuel-air mixing inside the engine cylinder with slower spray tip penetration than that of the baseline case without CMC device. Combustion images show that the flame growth is faster with CMC device compared to the similar case without CMC device.

A device has been designed and built to allow one to systematically investigate the dynamical behavior of a wide variety of torsional vibration absorbers (TVAs). These are devices that can passively absorb the torsional vibration of a wide range of rotating systems. The testing device allows different operating conditions to be studied and similarities and discrepancies between theoretical predictions and experimental results can be made. The manuscript emphasizes the design and capabilities of the device and discusses the instrumentation of the system. It also presents a limited number of experimental results along with the associated theoretical predictions.

Many engineering systems create unwanted noise that can be reduced by the careful application of engineering noise controls. When this noise travels down tubes and pipes, a tuned resonator can be used to muffle noise escaping from the tube. The classical examples are automobile exhaust and ventilation system noise. In these cases where a narrow frequency band of noise exists, a traditional engineering control consists of adding a tuned Helmholtz resonator to reduce unwanted tonal noise by reflecting it back to the source (Temkin, 1981). As long as the frequency of the unwanted noise falls within the tuned resonator frequency range, the device is effective. However, if the frequency of the unwanted sound changes to a frequency that does not match the tuned resonator frequency, the device is no longer effective. Conventional resonators have fixed tuning and cannot effectively muffle tonal noise with time-varying frequency.

The purpose of this work was to develop a fiber optic imaging system for use in flow visualization studies at the Michigan State University Engine Research Laboratory. A flexible fiber optic image carrier was coupled with a high speed rotating prism camera to create a unique imaging system which can easily reach remote location test sites. The flow visualization study was conducted on a motored 3.5 L four-valve engine test rig. A 40 watt pulsed copper vapor laser was synchronized with the camera to produce motion picture film at 5000 frames per second (fps). The image carrier which is attached to the camera contained an 80 degree field of view (FOV) tip adapter for viewing the entire cross-sectional area of the cylinder. The area imaged was a radial plane located 3 cm from the intake valves. The engine rig was motored at 850 rpm with a flow rate of 18 kg/hr. Entrained microballoon seeding particles were filmed as they traveled through the cylinder.

This work presents a method for simultaneously capturing visible and infrared images along with pressure data in an optical Diesel engine based on the International 4.5L VT275 engine. This paper seeks to illustrate the merits of each imaging technique for visualizing both in-cylinder fuel spray and combustion. The engine was operated under a part load, high simulated exhaust gas recirculation operating condition. Experiments examining fuel spray were conducted in nitrogen. Overlays of simultaneously acquired infrared and visible images are presented to illustrate the differences in imaging between the two techniques. It is seen that the infrared images spatially describe the fuel spray, especially fuel vapors, and the fuel mixing process better than the high-speed visible images.

In this paper results are presented from a study that investigates the use of centrifugally driven pendulum vibration absorbers for the attenuation of engine torsional vibrations. Such absorbers consist essentially of movable counterweights whose center of mass is restricted to move along a specified path relative to the rotational frame of reference. These devices are commonly used in light aircraft engines and helicopter rotors. The most common designs use a circular path for the absorber, tuned to a particular order of rotor disturbance, although more recent developments offer a wider variety of paths. Our goal here is to evaluate the system performance for a range of path types with different types of tuning. This analytical study is carried out for a simple mechanical model that includes a rotor and an absorber riding along a quite general path. Approximate solutions are obtained using a perturbation scheme and compared with detailed computational results.

Statistical Energy Analysis (SEA) is a useful tool for predicting the transmission of noise and vibration through the structures of automotive vehicles. This work discusses the identification of SEA internal loss factor parameters from experimental measurements of vehicle sound pressure levels and structural accelerations. A simple automotive vehicle SEA model can be constructed from elements idealized as uniform beams, flat plates and acoustic volumes. Such an SEA automotive vehicle model can accurately predict the vibro-acoustic response of an automotive vehicles when appropriate equivalent SEA parameters are identified from in situ experimental data. This paper will present an algorithm for identifying internal loss factors for SEA models. The paper will include an example of the application of the algorithm to identification of automotive vehicle internal loss factors from measured vehicle response data.

Our research contributes to the overall attempt to gain knowledge of the fluid dynamical processes in engines by applying a new measurement technique called LIPA (Laser Induced Photochemical Anemometry). It concentrates on detecting fundamental flow and mixing mechanisms by performing experiments on the induction stroke in an axisymmetric motored water analog model of a four stroke IC engine. We present results of the investigations done at an engine speed of 20 RPM in water (corresponding to 340 RPM in air) at three different valve lifts (3, 6, and 9 mm). Maps containing velocity vectors depict in 2D a toroidal recirculation pattern that scales with cylinder volume and they suggest that the recirculation pattern possesses the highest degree of order -- thus least mixing -- for 9 mm valve lift and the lowest for 3 mm valve lift. A fluid dynamic model on the basis of freestream jet characteristics has been proposed to account for this phenomenon.

Internal flow characteristics of a close coupled catalytic converter were examined by LDV measurements and high speed flow visualization. Although previous studies have been done on catalytic converters, they were conducted at steady state and using water flow seeded with a small quantity of tracer particles. The purpose of this study was to develop a better understanding of dynamic flows inside catalytic converters. The high speed flow visualization films and LDV results showed that areas of separation and circulation were present in the inlet region of the converter. Backflows into the neck of the converter were also observed. Each cylinder exhausted into a different region of the converter, with the front-middle region having the heaviest amount of flow. Large bursts of flow were created by each cylinder, while other regions of the inlet region showed backflows or very low flow rates. The midsection of the converter had a more uniform overall flow pattern.

This paper reports the development of vapor/liquid visualization systems based on an exciplex (excited state complex) formed between dimethyl- or diethyl-substituted aniline and trimethyl-substituted naphthalenes. Quantum yields of individual monomers were measured and the exciplex emission spectra as well as fluorescence quenching mechanisms were analyzed. Among the many systems and formulations investigated in this study, an exciplex consisting of 7% 1,4,6-trimethylnaphthalene (TMN) and 5% N,N-dimethylaniline (DMA) in 88% isooctane was found to be the best system for the laser-induced exciplex fluorescence (LIEF) technique, which is used to observe mixture formation in diesel or spark ignition (SI) engines. Observation of spectrally separated fluorescence from monomer in the gas phase and from exciplex in the gasoline fuel [1] requires that the exciplex forming dopants have boiling points within the distillation range of gasoline (20 to 215°C).

This paper presents the results of a combined theoretical and experimental study to find the relationship between a system's parameters and the sound generated when the system impacts against a rigid fixture. Although the particular physical structure investigated is a flexible cantilever beam, the approach adopted is such that the results are valid for a more general class of problem.

Squeak and rattle has become a primary source of undesired noise in automobiles due to the continual diminishment of engine, power train and tire noise levels. This article presents a finite-element-based methodology for the improvement of rattle performance of vehicle components. For implementation purposes, it has been applied to study the rattle of a glove compartment latch and corner rubber bumpers. Results from the glove compartment study are summarized herein. Extensions to other rattle problems are also highlighted.

A device consisting of a mass-loaded cantilever and a striker block mounted on an electromagnetic shaker can be used to create a wide variety of mechanical rattle sounds. The construction of the rattle mechanism is described and illustrated with diagrams. Examples of the different qualities of rattles that can be produced are presented as plots of microphone waveforms. The applications of such a device are primarily in support of the development, testing, and evaluation of rattle detection systems based on human experts or computers.

National Accident Sampling System (NASS) data, for the years 1993-1995, suggests a high frequency of tibiofemoral joint fractures among automotive accident victims. In addition, the NASS data also suggests that these injuries may be attributable to direct axial loading via the floor pan and/or the foot controls. Hirsch and Sullivan (1965), and Kennedy and Bailey (1968) conducted quasi-static fracture experiments axially compressing human tibiofemoral joints at low rates of loading and low angles of flexion. Hirsch and Sullivan observed a mean fracture load of approximately 8 kN compared to approximately 16 kN in the Kennedy and Bailey study. The current tibiofemoral joint injury criterion used in anthropomorphic dummies is based on Hrisch and Sullivan''s data. The current study involved impact experiments on human tibiofemoral joints (aged 71.4±11.2) directed in a superior direction along the axis of the tibia with the joint flexed 90°.