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Currently, conventional spark-ignition engines are unfit to satisfy the growing customer requirements on efficiency while complying with the legislations on pollutant emissions. New ignition systems are being developed to extend the engine stable operating range towards increasing lean conditions. Among these, the Radio-Frequency corona igniters represent an interesting solution for the capability to promote the combustion in a much wider region than the one involved by the traditional spark channel. Moreover, the flame kernel development is enhanced by means of the production of non-thermal plasma, where low-temperature active radicals are ignition promoters. However, at low pressure and at high voltage the low temperature plasma benefits can be lost due to occurrences of spark-like events. Recently, RF barrier discharge igniters (BDI) have been investigated for the ability to prevent the arc formation thanks to a strong-breakdown resistance.

Fossil fuel depletion and air pollution have accelerated the transformation and upgrading of the internal combustion engine industry. The argon-oxygen atmosphere engine has the advantages of “zero emission” and high thermal efficiency, but the knocking problem constrains the engine to operate at a lower compression ratio. In this paper, the effect of water spraying technology on the knocking combustion and combustion characteristics of a hydrogen-argon oxygen engine is investigated by numerical simulation. A one-dimensional thermodynamic model and a three-dimensional numerical model of the hydrogen-argon oxygen engine are established and validated by aligning the model with the data of the real engine. Firstly, investigate the effect of in-cylinder water spraying timing on knock suppression and combustion characteristics of hydrogen argon oxygen engines. 570 ° CA to 600 ° CA is the optimal water spraying timing range for suppressing knock.

This study presents a numerical analysis of the flow around an Audi R8 sports car and the effect of adding a National Advisory Committee for Aeronautics (NACA) 6412 base profile wing. The mass and momentum conservation laws are solved using Reynolds-averaged Navier–Stokes (RANS) equations. The turbulence is simulated using the realizable k–ε model, and the pressure–velocity coupling is solved using the semi-implicit method for pressure-linked equations (SIMPLE). The analysis was performed in the ANSYS Fluent-19 numerical code. The numerical results were validated with experimental data and numerical simulations from other studies in the open literature on vehicles without wings. The analyses included quantifying drag, lift, lateral forces, and their respective coefficients. When the wing was attached to the rear of the vehicle, there was a considerable increase in the aerodynamic load with an increase in drag.

Electrostatic Rotary Bell Sprayers (ERBSs) have been widely used in the painting industry, especially in the automotive and aerospace industries, due to their superior performance. The effects of the applied voltage and paint droplet charge values on the spraying pattern and coating Transfer Efficiency (TE) in the ERBS, including a high-voltage ring for spray cloud control, have been studied numerically in a wide range of droplet size distribution. A 3D Eulerian-Lagrangian numerical analysis is implemented under the framework of the OpenFOAM package. The fluid dynamics of turbulence, primary and secondary breakup procedures are modeled using a large eddy simulation (LES) model, Rosin-Rammler distribution, and modified TAB approach, respectively.

Soot formation in DI diesel engines is caused by the in-homogeneous mixture of evaporated diesel fuel and air. Locally fuel-rich regions are the origin of soot formation. Even though the higher temperatures during the combustion process assist the oxidation process, the formation of NOx pollutants increases with increasing temperature, which is known as soot-NOx trade-off. One measure to reduce both soot and NOx emissions uses an emulsified fuel where the fuel is replaced by an emulsion of diesel-water in order to homogenise the mixture formation process. The influence of such an emulsion on the pollutant formation was numerically examined using the CFD code KIVA-3V for the flow and the Representative Interactive Flamelet model (RIF) for the combustion modelling and combustion turbulence interaction respectively. The diesel fuel was replaced by a surrogate fuel consisting of 70% n-decane and 30% α-methylnaphthalene.

The problem of exhaust flow from a high speed two-cycle engine is investigated for a specific exhaust pipe geometry. The attempt is to simulate accurately the ramming and scavenging effects of the pressure waves at the exhaust port in the cylinder of such an engine, over a range of engine speeds. Using a one-dimensional, compressible, inviscid fluid model, the GODEL hydrodynamic computer code developed by Chapman is employed to accomplish the simulation. Two differencing schemes are examined and compared. Further, we discuss briefly the implications of our results as regards (i) the applicability of certain solution algorithms to the particular problem; and (ii) the future of employing such numerical techniques to the analysis of exhaust and other internal combustion engine flows.

A two-dimensional, implicit finite-difference method of the control-volume variety, a two-equation model of turbulence, and a discrete droplet model have been used to study the flow field, turbulence levels, fuel penetration, vaporization and mixing in Diesel engine-type environments. Good agreement with the droplet penetration data of Hiroyasu and Kadota has been obtained for a range of ambient pressures neglecting the effects of void fraction, droplet coalescence and droplet collisions in the simulation. The model has also been used to study the effects of the intake swirl angle on the flow field, turbulence levels, fuel penetration, vaporization and mixing in a two-stroke Diesel engine operating under motored conditions. Numerical simulations indicate that as the intake swirl angle is increased, the fuel penetration, vaporization and mixing increase.

In order to spread market opportunities, Volkswagen do Brasil Ltda - Truck and Bus Operation has adopted in conjunction with T-Systems do Brasil Ltda computer-aided analysis techniques that have been revolutionized engineering design in several important areas, notably in the optimization of systems where heat transfer and fluid flow are present. The main goal is to reduce the lead time to develop a new system and to obtain a better understanding of the physical aspects of the phenomenon involved. The proposed paper aims to present the numerical simulation of the flow around two wheel systems, for a new Volkswagen Truck. The main practical application of this investigation is to evaluate the air flow assessment in the region of the brake system and determine flow rate and global heat transfer coefficient. With this study, it is possible to decide which wheel system is more efficient from the brake refrigeration point of view.

The present study shows how the application of computational fluid dynamics can help to understand and optimize the flow field in a passenger compartment in order to achieve an optimum of thermal comfort for the occupants. The flow field and temperature distribution in a passenger compartment have been calculated using the commercial CFD program STAR-CD. In combination with a thermophysiological model for the passengers, the computational results are used to evaluate the thermal comfort of the occupants and compare different geometrical modifications. The computational mesh consisting of around 3 millions hexahedra cells resolves all geometrical details of the car cabin including the air ducts, air nozzles and louvers. Natural convection, heat conduction and radiation are taken into account. One standard climatisation mode, the winter heat-up mode has been simulated. A special emphasis of the numerical investigations is the optimization of the ventilation of the front and rear legroom.

In this study the numerical simulation of the flow through an alternator inside an engine compartment of a passenger car is investigated. Specifically the interaction of the flow through the alternator with the flow through the engine compartment is explored in detail. The results are compared with a corresponding numerical simulation of an alternator in a surrounding of a test facility and with a numerical simulation of the flow through an engine compartment without taking into account the internal flow through the alternator. Finally the air temperature near the alternator and also the temperature of some components inside the alternator are compared with experimental values measured during a typical load case used for the thermal protection of the passenger car.

Friction Stir Spot Welding (FSSW), originally developed by GKSS (Germany), has a strong potential to find applications in the automotive and aerospace industries. At the present time, research efforts are taking place to gain a better understanding of the process, to explore different tool configurations, and to optimize the set of process parameters. In this regard, having reliable numerical models capable to simulate FSSW can be useful to reduce the number of physical experiments required in those studies. In this paper, a simplified isothermal three-dimensional Finite Element model of the initial plunge phase of the FSSW process is presented. The model, based on a solid mechanics approach, was developed using the commercial software ABAQUS/Explicit. The results of the simulations are compared against experimental information corresponding to similar tool geometry, sequence of operations, and process parameters.

Two-stroke engine gas exchange simulation requires several significant code modifications in comparison to standard four-stroke application. This paper describes the present work based on the PROMO code. Important features currently modelled are a scavenging model, a crank case model and a reed valve model. First results based on calculations for a crank case scavenged engine show the present state of the code and the influence of some design parameters on the engine performance.

Developing piston assemblies for internal combustion engines faces the conflicting priorities of blow-by, friction, oil consumption and wear. Solving this conflict consists in finding a minimum for all these parameters. This optimization can only be successful if all the effects involved are understood properly. In this paper only blow-by and its associated flow paths for a diesel engine in part load operating mode are part of a detailed numerical investigation. A comparison of the possibilities to do a CFD analysis of this problem should show why the way of modeling described here has been picked. Further, the determination of the complex geometry, which results in a challenging set of calculations, is described. Besides the constraints for temperature and pressure, a meshing method for the creation of a dynamic mesh that is capable of describing the movement of all three rings of the piston ring pack simultaneously is also explained.

The outward-opening piezoelectric injector can achieve stable fuel/air mixture distribution and multiple injections in a single cycle, having attracted great attentions in direct injection gasoline engines. In order to realise accurate predictions of the gasoline spray with the outward-opening piezoelectric injector, the computational fluid dynamic (CFD) simulations of the gasoline spray with different droplet breakup models were performed in the commercial CFD software STAR-CD and validated by the corresponding measurements. The injection pressure was fixed at 180 bar, while two different backpressures (1 and 10 bar) were used to evaluate the robustness of the breakup models. The effects of the mesh quality, simulation timestep, breakup model parameters were investigated to clarify the overall performance of different breakup model in modeling the gasoline sprays.

Hydroforming is a metal forming process that uses in addition to the usual forming tools, water under pressure. This method has several advantages, such as: high precision and elimination of some common defects of traditional forming processes (non uniform thickness and local buckling). This work presents numerical simulations of the hydroforming process, using the finite element code for large deformation problems METAFOR [1,2,3] (METAl FORming). To perform the analysis, a full non-linear algorithm is used and contact between bodies is taken into account. A 3-D CAD-type graphic environment has been developed for modeling the tools.

In Diesel engines equipped with jerk injection pumps there appear many effects derived from fuel compressibility and the short duration of injection. As a result of them, cavitation, secondary injection, dribble and other hazardous phenomena may occur. With the objective of studying these processes, a simulation model for an indirect Diesel injection system has been developed. The mathematical model takes into account cavitation and gas dissolved effects. A relationship is obtained theoretically to reproduce the dependence of density of fuel oil with the pressure. The deduction of this equation is based on some hypotheses: that the amount of air in the liquid is constant, the process isothermal, the liquid fuel and its vapour are in thermodynamic equilibrium, and finally, that the temperature, pressure and velocity of both phases are identical. The unidimensional two-phase flow equations are simplified and employed to resolve the high-pressure line.

The boundary conditions of the inner vehicle compartment, such as sound absorption of the lining materials and panel vibrations have a considerable influence in the acoustic comfort of the passengers and driver. The numerical simulation of the irregular cabin with the finite element method (FEM) and/or the boundary element method (BEM) have a great advantages in the modeling of the acoustic energy injected and/or absorbed by the inner cabin surfaces. In this paper, a numerical modeling of a vehicle cabin is presented by FEM and BEM. The panel vibration, between the engine compartment and passenger compartment was considered as the noise source. Prediction of the sound pressure level generated at the driver ear position was calculated for different absorption materials at the roof. This model allows optimization of the lining material and investigates the effect of panel vibration, leakage due to gaps and holes and also cabin geometry.

The Diffuse Field Absorption Coefficient (DFAC) is a physical quantity very often used in the automotive industry to assess the performance of sound absorbing multilayers. From a theoretical standpoint, such quantity is defined under rather ideal conditions: the multilayer is assumed to be infinite in extent and the exciting acoustic field is assumed to be perfectly diffuse. From a practical standpoint, in the automotive industry the DFAC is generally measured on samples having a relatively small size (of the order of 1m2) and using relatively small cabins (in the order of 6-7 m₃). It is well known that both these factors (the finite size of the sample and the small volume of the cabin) can have an influence on the results of the measurements, generating deviations from the theoretical DFAC.

Some of the current engine design requirements are the reduction of the engine weight and size and the power increasing. The components, like the connecting rod, should be re-designed in order to attend the trends. Other important variables are the increase of the engine speed and the peak cylinder pressure, higher the engine speed and peak cylinder pressure, higher the inertia and the gas pressure loads, respectively [2]. The combination of the trends mentioned before directly affects the con-rod bearing performance. In most cases, the optimization of the bearing profile can generate a significant improvement on the bearing performance. The use of the EHL numerical simulation is a powerful tool to design bearings and evaluate their performance. This paper presents, based on the EHL theory, a numerical evaluation of the performance of different connecting rod bearing profiles, both in circumferential and axial bearing directions.

In the present paper the application of a scavenging model in a two stroke Diesel engine with four radial cylinders and symmetric scavenging forced by a turbocharger is described. Besides the engine model, the turbocharger and pulse converter, where the exhaust pipes end, were simulated as described in the text. The empirical coefficients have been fixed by means of the comparative study of the results obtained with a three-dimensional model. The simulation model has been used in two cases, for the validation of itself, comparing the results obtained with the measurements in a test rig, and for the prediction of the performances of the four radial cylinders of the Diesel engine described in a previously published paper.