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The efficiency of the NOx Storage and Reduction (NSR) catalysts used in the aftertreatment of diesel engine exhaust gases can potentially be increased by using reactive reductants such as CO and H₂ that are formed during in-cylinder combustion. In this study, a multi-dimensional computational fluid dynamics (CFD) code coupled with complex chemical analysis was used to study combustion with various fuel after-injection patterns. The results obtained will be useful in designing fuel injection strategies for the efficient formation of CO.

A 3-dimensional numerical study has been conducted investigating the combustion process in a VW 1.9l TDI Diesel engine. Simulations were performed modeling the spray injection of a 5-hole Diesel injector in a pressure chamber. A graphical methodology was utilized to match the spray resulting from the widely used Discrete Droplet Spray model to pressure chamber spray images. Satisfactory agreement has been obtained regarding the simulated and experimental spray penetration and cone angles. Thereafter, the combustion process in the engine was simulated. Using engine measurements to initialize the combustion chamber conditions, the compression stroke, the spray injection and the combustion simulation was performed. The novel RTZF two-zone flamelet combustion model was used for the combustion simulation and was tested for partial load operating conditions. An objective analysis of the model is presented including the results of a numerical parameter study.

The design of reliable DPF systems has proved a complex and demanding task that is increasingly being assisted by modeling. 1-D but also 2-D (axisymmetric) modeling has already been applied in design optimization case studies, with varying degrees of success. The introduction of advanced technology SiC and cordierite filters with modular structure and the need to accurately model transient temperature and stress fields in low space velocity scenarios, made necessary the shift to 3-D modeling. In this paper, 3-D modeling is carried out in an effective and reliable way, by interfacing a well-documented and validated 1-D model with the ABAQUS commercial FEM software. The new modeling methodology proves a powerful tool in the hands of the filter and diesel exhaust system design engineer.

A three-dimensional model for premixed- charge naturally-aspirated rotary engine combustion is used to identify combustion chamber geometries that could lead to increased indicated efficiency for a lean (equivalence ratio =0.75) natural gas/air mixture. Computations were made at two rpms (1800 and 3600) and two loads (approximately 345 Kpa and 620 Kpa indicated mean effective pressure). Six configurations were studied. The configuration that gave the highest indicated efficiency has a leading pocket with a leading deep recess, two spark plugs located circumferentially on the symmetry plane (one after the minor axis and the other before), a compression ratio of 9.5, and an anti-quench feature on the trailing flank.

A three-dimensional combustion model for a direct-injection stratified-charge rotary engine is used to identify modifications to the engine that should lead to better indicated efficiency. The engine has a single spark plug positioned alongside a single-hole pilot injector in a cavity located after the minor axis and a five-hole main injector that is located before the minor axis. It is predicted that a second ignition source located upstream of the main injector will lead to an increase in indicated efficiency of 6-8% if it ignites the mixture consistently. The computations were made at high and low engine speeds and loads, covering a significant part of the practical operating range of the engine. It is also predicted that the gain in efficiency of the engine with two ignition sources would be 7-10%, instead of 6-8%, if a two-hole pilot injector is also used instead of the one-hole pilot.

A three-dimensional model for a direct injection stratified-charge rotary engine has been employed to study two modifications to the pocket geometry of the engine. In one modification, a pocket is located towards the leading edge of the rotor and is shown to produce recirculation within the pocket and faster burning. In the second modification, a two pocket rotor with two injectors and two spark plugs is studied. It appears that this should result in better utilization of the chamber air. It also appears that both modifications rhould result in higher efficiency of the direct-injected stratifiedcharge rotary engine. However extensive computations are required before a final conclusion is reached and before specific recommendations can be made.

A three-dimensional combustion model of a direct-injection stratified-charge rotary engine is used to identify modifications that might lead to better indicated efficiency. The engine, which has a five-hole main injector and a pilot injector, is predicted to achieve better indicated efficiency if a two-hole ‘rabbit-ear’ pilot injector is used instead of its present single-hole pilot injector. This rabbit-ear arrangement is predicted to increase the surface area of the early flame (on account of better distribution of the fuel), and thereby result in an increased overall burning rate. Computations were made at high and low engine speeds and loads, encompassing the practical operating range. It is concluded that the modified pilot injector will increase indicated efficiency by about 5% within the computed operating range.

The dynamics of vehicle front end crash are studied using the ADAMS dynamic simulation code. The analysis is carried out in three dimensions and can capture the behavior associated with an asymmetrical structure or impact mode. Subroutines which allow the modeling of structural crush and plastic hinge formation, contact forces and friction forces are discussed. The method is relatively inexpensive, but does require a good understanding of the problem on the part of the analyst. A discussion of the techniques that are used to model the structural system is given. The results of the analysis are compared with experimental data and the correlation is very encouraging.

Until recently, the application of the detailed chemistry approach as a predictive tool for engine modeling has been sort of a “taboo” for different reasons, mainly because of an exaggerated rigor to the chemistry/turbulence interaction modeling. In terms of this ideology, if the interaction cannot be simulated properly, the detailed chemistry approach makes no sense. The novelty of the proposed methodology is the coupling of a generalized partially stirred reactor, PaSR, model with the high efficiency numerics to treat detailed oxidation kinetics of hydrocarbon fuels. In terms of this approach, chemical processes are assumed to proceed in two successive steps: the reaction follows after the micro-mixing is completed on a sub-grid scale.

3-D horn is a vehicle to vehicle communication-based technology which helps in reducing the noise pollution, which occurs, due to honking of automobile horns by letting only the drivers of the automobile to hear the horns and not the whole environment around him. To achieve this, several relatively small horn speakers are placed inside the car. These speakers are controlled by drivers of other cars. In this way honking will be heard only by the drivers. The most unique feature of this technology is the 3-D effect caused by the speakers which will let the driver know the location of the outside car which is honking. The 3-D effect is achieved by varying the intensity and proper allotment of sound to the positioned speakers in such a way that it will give the feel of the location of the outside car to the driver. Human detection is another important feature this technology provides. It will recognize whether the horn is honked for an automobile or for a human.

In-cylinder flows in a motored four-valve SI engine were examined by simultaneous three-component LDV measurement. The purpose of this study was to develop better physical understanding of in-cylinder flows and quantitative methods which correlate in-cylinder flows to engine performance. This study is believed to be the first simultaneous three-component LDV measurement of the air flow over a planar section of a four-valve piston-cylinder assembly. Special attention is paid to the tumble formation process, three-dimensional turbulent kinetic energy, and measurement of the tumble ratio. The influence of the induction system and the piston geometry are believed to have a significant effect on the in-cylinder flow characteristics. Using LDV measurement, the flows in two different piston top geometries were examined. One axial plane was selected to observe the effect of piston top geometries on the flow field in the combustion chamber.

In order to reproduce heavy bass with a small diameter loudspeaker for automotive use similar to the intensity and low distortion of a home-use Hi-Fi system, a large volume velocity must be obtained. This is done by lowering the minimum resonant frequency of system and by linearly expanding the amplitude range of diaphragm. We have developed a 3-D woofer system using a centering suspension that consists of four tubes of square cross-section continuously laid in the circumferential direction and a cone suspension that has V-shaped pleats in both of the circumferential and diameter directions for the vibration system. The results are good acoustic characteristics in an automotive cabin that are low in distortion with high output in the low frequency range up to 100Hz.

A novel computer vision technique for rapid measurement of surface coordinates is presented. The technique is based on the marriage of a digital fringe projection technique and a fringe-phase extraction algorithm. A digitally controlled video signal in the form of linear and parallel fringes of cosinusoidal intensity variation is projected onto an object. The fringe pattern is perturbed by the three-dimensional object surface with fringe-phase containing information on the depth of the object. A phase extraction algorithm is used to determine the fringe-phase distribution, from which the three-dimensional surface coordinates are determined. The theoretical basis of this technique and some experimental results are presented in this paper.

An investigation of the possibility to extend the 3-dimensional modeling capabilities from conventional diesel to the HCCI combustion mode simulation was carried out. Experimental data was taken from a single cylinder engine operating with early injections for the HCCI and a split-injection (early pilot+main) for the high speed Diesel engine operation. To properly phase the HCCI mode in the experiments, high amounts of cooled EGR and a decreased compression ratio were used. In numerical simulation performed using KIVA3-V code, modified to incorporate the Detailed Chemistry Approach the same conditions were reproduced. Special attention is paid on the analysis of the events leading up to the auto-ignition, which was reasonably well predicted.

Manufacturers of heavy-duty diesel engines are facing increasingly stringent, emission standards. These standards have motivated new research efforts towards improving the performance of diesel engines. The objective of the present program is to develop a comprehensive analytical model of the diesel combustion process that can be used to explore the influence of design changes. This will enable industry to predict the effect of these changes on engine performance and emissions. A major benefit of the successful implementation of such models is that engine development time and costs would be reduced through their use. The computer model is based on the three-dimensional KIVA-II code, with state-of-the-art submodels for spray atomization, drop breakup / coalescence, multi-component fuel vaporization, spray/wall interaction, ignition and combustion, wall heat transfer, unburned HC and NOx formation, and soot and radiation.

Ever increasing specific power of diesel engines has put huge demand on effective thermal management of the pistons for the desired reliability and durability. The piston temperature control is commonly achieved by injecting cooling oil into piston galleries, but the design of the cooling system as well as the boundary conditions used in FEA simulations have so far relied mostly on empirical methods. A numerical procedure using 3D computational fluid dynamics (CFD) has therefore been developed to simulate the cooling process and to estimate the cooling efficiency of gallery. The model is able to predict the detailed oil flow and heat transfer in gallery, of different designs and engine applications, under dynamic conditions. The resulted spatially resolved heat transfer coefficient from the CFD model, with better accuracy, enables improved prediction of piston temperature in finite element analysis (FEA).

The thermal performance of an engine coolant system is efficient when the engine head temperature is maintained within its optimum working range. For this, it is desired that air should not be entrapped in the coolant system which can lead to localized hot spots at critical locations. However, it is difficult to eliminate the trapped air pockets completely. So, the target is to minimize the entrapped air as much as possible during the coolant filling and deaeration processes, especially in major components such as the radiator, engine head, pump etc. The filling processes and duration are typically optimized in an engine test stand along with design changes for augmenting the coolant filling efficiency. However, it is expensive and time consuming to identify air entrapped locations in tests, decide on the filling strategy and make the design changes in the piping accordingly.

Increased torque values passing from engine to transmission have, increasingly become a problem regarding shaft misalignment. Engineers are restricted with regard to applying ISO standards when investigating bearing life cycles as they tend only to cover normal [radial thrust] load conditions. Depending on the application, the need has arisen for numerical models to determine reduction in normal life cycles due to abnormal running conditions. The Simulia Finite Element package Abaqus v6.7 provides trends in the deformations, contact pressures and their respective distribution. It was found the most efficient profile, with regards to a uniform contact pressure, under both radial and misaligned conditions is the toroidal profile.

A 3-D numerical analysis model of transient heat transfer among the multi-component coupling system in combustion chamber of internal combustion engine has been developed successfully in the paper. The model includes almost all solid components in combustion chamber, such as piston assembly, cylinder liner, cylinder head gasket, cylinder head, intake valves and exhaust valves, etc. With two different coupling heat transfer modes, one is the lubricant film heat conduction between two moving components, another is the contact heat conduction between two immovable solid components, and with the direct coupled-field analysis method of FEM, the heat transfer relation among the components is established. The simulation result dedicates the transient heat transfer process among the components such as moving piston assembly and cylinder liner, moving valves and cylinder head. The effect of cylinder head gasket on heat transfer among the components is also studied.

Nowadays, due to the stringent engine emission norms, an efficient technique is required to reduce oxides of nitrogen (NOx) from automobiles especially from the lean burn engines. Selective Catalytic Reduction (SCR) is found to be an efficient after treatment method used to reduce oxides of nitrogen (NOx) from the exhaust. However, for light duty vehicles, because of the limited size of the catalysts, ammonia slip nullifies its advantages. Lack of uniformity of ammonia at the SCR monolith entrance causes ammonia slip. This study addresses the effect of injection parameters, location of injector and shape of injector upon the flow parameters, exhaust gas temperature and flow rate. The results obtained from this study provide useful guidelines for optimizing the injection parameters to avoid the ammonia slip. The evaporation of Urea Water Solution (UWS) is also investigated.