Automotive Science and Engineering
Volume:1 Issue: 3, Summer 2011

A newly developed heavy duty diesel engine in dual fuel mode of operation has been studied in detail. The main fuel would be natural gas and diesel oil as pilot injection. The importance and effects of mixture preparation and formation through ports, valves and in cylinder flow field with different swirl ratio and tumble on diesel combustion phenomena is an accepted feature which has been studied using a developed CFD model together with a KIVA3-V2 code. This analysis is capable to investigate engine geometry, valves lift, and valves timing turbo charging, and its effects on dynamic flow field with variable dual fuel ratio on power and emission levels output. This complete open cycle study of a dual fuel engine has been carried out originally and for the first time and by considering complete grid consisted of four moving valves, two intake ports, two exhaust ports, and the port runners. It is found that important complex flow structures are developed during the intake stroke. While many of these structures decay during the compression stroke, swirl and tumble can survive. The effect of increased swirl ratio at the end of the compression stroke for the D87 engine with a piston bowl is clearly observed in this study. This is important for aiding in good fuel spray atomization. The formation, development, and break-up of tumble flow are seen, contributing to an increase in turbulent kinetic energy at the end of the compression stroke. The complete engine flow field, i.e. the inlet jet, and formation of swirl in the intake ports, is also clearly shown in the study. Results of these simulations assist in the improved understanding of the intake process and its influence on mixture formation and flow field in a dual fuel engine.

Thermal modeling of an automotive cabin was performed in this paper to predict the inside cabin air temperature. To implement this task, thermal and ventilation loads were estimated and the mass and energy balance conservation equations for dry air and water vapor with considering a new parameter (air circulation ratio) as well as the balance equations of internal components of a cabin were derived and solved simultaneously. The performance of the proposed thermal modeling of a cabin was compared with the data collected from hot room experimental tests. These tests were run for various design parameters such as evaporating cooling load and cabin size (air volume inside cabin). The comparison of experimental and numerical results showed a good agreement. Parametric analysis with three parameters namely, vehicle speed, number of passengers, and A/C air mass flow rate was performed to investigate the effects of these parameters on cabin air temperature.

Parametric design optimization of an automotive body crashworthiness improvement is presented. The thicknesses of parts are employed as design variables for optimization whose objective is to increase the maximum deceleration value of the vehicle center of gravity during an impact. Using the Taguchi method, this study analyzes the optimum conditions for design objectives and the impact factors and their optimal levels are obtained by a range analysis of the experiment results. A full frontal impact is implemented for the crashworthiness simulation in the nonlinear dynamic code, LS-DYNA. The controllable factors used in this study consist of the six inside foreheads structural parts, while design parameters are relevant thicknesses. The most interestingly the maximum deceleration of the vehicle center of gravity is reduced by 20% during a full frontal impact while several parts experience mass reduction.

Multidimensional modelling of open-cycle process of OM355 engine was developed. Calculations for computational mesh were carried out. The results of the model were validated by experimentally measured in-cylinder pressure and the good agreement between calculations and measurements approved the trustworthy of numerical code. Results included pressure, temperature, emission and Rate of heat release diagrams were represented for the full cycle. Further more local flow field velocity vectors were indicated. The results show the importance of open-cycle simulations in automotive researches.

Nonlinear hunting speeds of railway vehicles running on a tangent track are analytically obtained using Hopf bifurcation theory in this paper. The railway vehicle model consists of nonlinear primary yaw dampers, nonlinear flange contact stiffness as well as the clearance between the wheel flange and rail tread. Linear and nonlinear critical speeds are obtained using Bogoliubov method. A comprehensive parametric study is then carried out and effects of different parameters like the magnitudes of lateral clearance, damping values, wheel radius, bogie mass, lateral stiffness and the track gauge on linear and nonlinear hunting speeds are investigated.

This article aims at strategic vision to technology and suggests a strategic planning for this purpose. The main emphasis in this article is on strategic report compilation in the framework of strategic vision and covers issues such as identification of strategic planning dimensions and strategic vision levels, technology priority setting, environment monitoring, focus on costumer needs, methods of strategic vision compilation and future research methods. This article also concentrates on R;D strategies in a separate section. Furthermore, a separate section is dedicated to strategic vision in automotive industry and issues are discussed related to Iran Khodro Co. strategic visions. At the end, a model is presented for strategic vision compilation.

Homogenous Charge Compression Ignition (HCCI) engines hold promise of high fuel efficiency and low emission levels for future green vehicles. But in contrast to gasoline and diesel engines, HCCI engines suffer from lack of having direct means to initiate combustion. A combustion timing controller with robust tracking performance is the key requirement to leverage HCCI application in production vehicles. In this paper, a two-state control-oriented model is developed to predict HCCI combustion timing for a range of engine operation. The experimental validation of the model confirms the accuracy of the model for HCCI control applications. An optimal integral state feedback controller is designed to control the combustion timing by modulating the ratio of two fuels. Optimization methods are used in order to determine the controller’s parameters. The results demonstrate the designed controller can reach optimal combustion timing within about two engine cycles, while showing good robustness to physical disturbances.