Showing 341 results for Type of Study: Research
N. Gajarlawar, G. Amba Prasad Rao,
Volume 2, Issue 3 (7-2012)
Abstract
The current regulated particle metric in vehicle emissions is the total mass, while during last decade
interest in number size distribution has increased. Various international studies on epidemiology and
toxicology have reported the adverse effect of the particle matter on public health. The UNECE group of
experts on pollution and energy (GRPE) under particle measurement program (PMP) are under the process
of finalization long term certification standard concerning particle emissions. The current study was done in
order to investigate the number concentration from a range of Indian multi utility vehicles. These were
equipped with various sizes of diesel engine over the new European driving cycle (NEDC) cycle using
same oil specification. The vehicles chosen were meeting emission norms ranging from Euro3 (E-3) to
Euro5 (E-5) and using the corresponding fuel specification as specified for the norms. In order to meet the
strict emission norms, penetration of common rail injection system in the Indian market is inevitable. The
use of higher injection pressure, advanced after treatment systems such as diesel particle filters (DPF), is
the motivation for the work to access the number concentration, an important metric of particle matter in
view of future emission norms. It is clearly revealed that different vehicles equipped with different capacity
engines exhibits similar diesel particle emission characteristics. Also, as the particle mass is decreasing
with the stringent emission norms reduces the particle number concentration.
A. Kakaee, M. Keshavarz,
Volume 2, Issue 3 (7-2012)
Abstract
In this study it has been tried, to compare results and convergence rate of sensitivity analysis and conjugate gradient algorithms to reduce fuel consumption and increasing engine performance by optimizing the timing of opening and closing valves in XU7/L3 engine. In this study, considering the strength and accuracy of simulation GT-POWER software in researches on the internal combustion engine, this software has been used. In this paper initially all components of engine have been modeled in GT-POWER. Then considering the experimental result, results confirmed the accuracy of the model. After model verification, GT-POWER model with MATLAB-SIMULINK are coupled each other, to control the inputs and the outputs by sensitivity analysis and conjugate gradient algorithms. Then the results compared with experimental results of initial engine too. The results indicated that optimal valve timing significantly reduced brake specific fuel consumption and when is used variable valve system for opening and closing angle of intake and exhaust valves, the mean improvement percentage in brake specific fuel consumption from sensitivity analysis is nearly 5.87 and from conjugate gradient is about 6.69. too, for example with increasing engine speed late closing intake valve causes optimized brake specific fuel consumption and from 3500rpm this trend stops and in 4000rpm and 4500rpm early closing of intake valve results in more optimized brake specific fuel consumption. Then up to 6000rpm again late closing of valve would be favorable. Also results indicated that convergence rate of conjugate gradient algorithm to reaching the optimal point is more than sensitivity analysis algorithm.
P. Mohammadi, A.m. Nikbakht, M. Tabatabaei, Kh. Farhadi,
Volume 2, Issue 3 (7-2012)
Abstract
Global air pollution is a serious threat caused by excessive use of fossil fuels for transportation. Despite the
fact that diesel fuel is a big environmental pollutant as it contains different hydrocarbons, sulphur and crude
oil residues, it is yet regarded as a highly critical fuel due to its wide applications. Nowadays, biodiesel as a
renewable additive is blended with diesel fuel to achieve numerous advantages such as lowering CO2, and
CO emissions as well as higher lubricity. However, a few key drawbacks including higher production cost,
deteriorated performance and likelihood to increase nitrogen oxide emissions have also been attributed to
the application of diesel-biodiesel blends. Expanded polystyrene (EPS), known as a polymer for packaging
and insulation, is an ideal material for energy recovery as it holds high energy value (1 kg of EPS is
equivalent to 1.3 liters of liquid fuel). In this study, biodiesel was applied as a solvent of expanded
polystyrene (EPS) during a special chemical and physical treatment. Various percentages of EPS in
biodiesel blended diesel were tested to evaluate the fuel properties, emissions and performance of CI
engine. The results of the variance analysis revealed that the addition of the additive improved diesel fuel
properties by increasing the flash point as well as the reduction of density and viscosity. Despite a 3.6%
reduction in brake power, a significant decrease in brake specific fuel consumption (7.26%) and an increase
in brake thermal efficiency (7.83%) were observed at the full load and maximum speed of the engine.
Additionally, considerable reductions of CO, CO2, NOx and smoke were achieved.
S.d. Oduro,
Volume 2, Issue 3 (7-2012)
Abstract
This thesis looked at the effect of clay and silt soil blocking the heat transfer area of the radiator and its
effect on the engine coolant through the conduct of experiments and a mathematical model developed. The
results indicated that the percentage area covered resulted in a proportional increase of the inlet and outlet
temperatures of the coolant in the radiator. The mathematically model developed also predicted the
experimental data very well. Regression analysis pointed out that every 10% increase area of the radiator
covered with silt soil resulted in an increase of about 17 oC of the outlet temperature of the radiator coolant.
Similarly, using clay as a cover material, 10% of the area covered of the radiator resulted in an increase of
about 20 oC of the outlet temperature of the radiator coolant. Statistical analysis pointed to the fact that the
result obtained for clay, silt and the mathematical model were not significantly different. Thus, irrespective
of the type of material that blocks the radiator surface area, the coolant rises with proportion of the radiator
covered.
P. Hosseini Tehrani, M. Talebi,
Volume 2, Issue 3 (7-2012)
Abstract
In this paper, finite element elastic contact analysis of a functionally graded (FG) hollow brake disk in
contact with pad, subjected to rotation, contact pressure and frictional heat is presented. The material
properties vary through the thickness according to a power-law characterised by a grading index, n. The
material property is purely steel at the core part and gradually moves and approaches to the ceramic
properties at the surfaces of the FGM disk. In this task, thermal analyses are performed on two ventilated
disk brake one of them is constructed of functionally graded composite material and the other is a
homogeny disk brake which is constructed of steel alloy. In this study three-dimensional finite element
model and ABAQUS software is used. Through comparison of temperature and displacement fields the
benefits of using functionally graded material is investigated. It is shown that temperature variation in
FGM disk is much lower than steel disks, it may be concluded that FGMs disk restrain the growth of
thermal perturbation and delay the contact separation..
R. Mirzaamiri, M. Esfahanian, S. Ziaei-Rad,
Volume 2, Issue 3 (7-2012)
Abstract
During the design and development of truck cabins, the safety of the driver and the front seat passenger in
an accident is an important task and should be considered. The cab must be designed in such a way that in
an accident a sufficient survival space is guaranteed. The aim of this study is to investigate the behavior of
Iran Khodro (IKCO) 2624 truck subjected to a complex crash test according to regulation ECE-R29. This
regulation is a comprehensive European regulation consisting of three tests: 1-Front impact test (Test A), 2-
Roof strength test (Test B), 3-Rear wall strength test (Test C). These tests do not consider the safety of the
occupant directly however, a III-50th% dummy was used to assess the cab’s deformations relative to the
driver survival space. A 3D finite element model of the cab and chassis was developed and subjected to
tests by using LS-DYNA software. The results indicate that the cab complied with Test A and C
successfully while it passed Test B marginally. Finally, two solutions are suggested and implemented to
improve the cab’s response for Test B.
A. Khalkhali, S. Samareh Mousavi,
Volume 2, Issue 3 (7-2012)
Abstract
In order to reduce both the weight of vehicles and the damage of occupants in a crash event simultaneously, it is necessary to perform a multi-objective optimization of the automotive energy absorbing components. In this paper, axial impact crushing behavior of the aluminum foam-filled thin-walled tubes are studied by the finite element method using commercial software ABAQUS. Comparison of the present simulation results with the results of the experiments reported in the previous works indicated the validity of the numerical analyses. A meta-model based on the feed-forward artificial neural networks are then obtained for modeling of both the absorbed energy (E) and the peak crushing force (Fmax) with respect to design variables using those data obtained from the finite element modeling. Using such obtained neural network models, a modified multi-objective GA is used for the Pareto-based optimization of the aluminum foam-filled thinwalled tubes considering three conflicting objectives such as energy absorption, weight of structure, and peak crushing force.
M. H. Shojaeefard, M. M. Etghani, M. Tahani, M. Akbari,
Volume 2, Issue 4 (10-2012)
Abstract
In this study the performance and emissions characteristics of a heavy-duty, direct injection, Compression ignition (CI) engine which is specialized in agriculture, have been investigated experimentally. For this aim, the influence of injection timing, load, engine speed on power, brake specific fuel consumption (BSFC), peak pressure (PP), nitrogen oxides (NOx), carbon dioxide (CO2), Carbon monoxide (CO), hydrocarbon (HC) and Soot emissions has been considered. The tests were performed at various injection timings, loads and speeds. It is used artificial neural network (ANN) for predicting and modeling the engine performance and emission. Multi-objective optimization with respect to engine emissions level and engine power was used in order to deter mine the optimum load, speed and injection timing. For this goal, a fast and elitist non-dominated sorting genetic algorithm II (NSGA II) was applied to obtain maximum engine power with minimum total exhaust emissions as a two objective functions.
M. Kazemi, M. Jooshani,
Volume 2, Issue 4 (10-2012)
Abstract
The suspension system of a vehicle is one of the most important parts which is involved in the process of
vehicle designing. When a vehicle suspension system is designed, the evaluation of its performance against
the road disturbances such as shocks and bumps are very important. The most commonly used systems
consist of four hydraulic Jacks with mobility in vertical line with low speed and low exactitude. This paper
offers a new mechanism for inspecting the suspension system of a vehicle using a parallel robot called
Stewart. This robot is a special kind of parallel robots with capability of movements in different directions
with high speed, accuracy and repeatability. In this paper the suspension system is evaluated on a quarter
model of a simulated vehicle with control and guidance of Stewart robot using PID controller. The Stewart
robot simulates the isolated and uneven bumps on a flat road in order to evaluate the given suspension
system, and to investigate some criteria such as comforting of the passengers and remaining of the vehicle
on the road. The results of the simulations show that the proposed method has a high accuracy, applicability
and flexibility as well as simplicity, compared to currently used mechanisms.
M. M. Jalili, A. H. Orafa,
Volume 2, Issue 4 (10-2012)
Abstract
A. Mohammadi, A. Jazayeri, M. Ziabasharhagh,
Volume 2, Issue 4 (10-2012)
Abstract
Porous media has interesting features in compared with free flame combustion due to the extended of the
lean flammability limits and lower emissions. Advanced new generation of internal combustion (IC)
engines are expected to have far better emissions levels both gaseous and particulate matter, at the same
time having far lower fuel consumption on a wide range of operating condition. These criteria could be
improved having a homogeneous combustion process in an engine. Present work considers simulation of
direct fuel injection in an IC engine equipped with a chemically inert porous medium (PM), having
cylindrical geometry that is installed in cylinder head to homogenize and stabilize the combustion process.
A numerical study of a 3D model, PM engine is carried out using a modified version of the KIVA-3V code.
Since there is not any published material for PM-engines in literature, the numerical results for combustion
waves propagation within PM are compared with experimental data available in the literature for a lean
mixture of air and methane under filtration in packed bed, the accuracy of results are very promising. For
PM-engine simulation the methane fuel is injected directly through a hot PM which is mounted in cylinder
head. Therefore volumetric combustion occurs as a result within PM and in-cylinder. The effects of
injection timing on mixture formation, pressure and temperature distribution in both phases of PM and incylinder
fluid together with combustion emissions such as CO and NO are studied in detail for an important
part of the cycle.
A. R. Noorpoor, A. Sadighzadeh, H. Habibnejad,
Volume 2, Issue 4 (10-2012)
Abstract
Diesel exhaust particles are a complex mixture of thousands of gases and fine substances that contain more
than 40 different environmental contaminants. Being exposed to these exhaust particles (called soot) can
cause lung damage and respiratory problems. Diesel particulate filters are used in many countries for
mobile sources as a legal obligation to decrease harmful effect of these fine particles. The size range of
these particles is varied from 0.01 to 1 µm. Moreover, it takes a long time to be settled when they are
outspread in atmosphere. In this paper, homogeneous plane standing waves are used to coagulate nano
particles in order to achieve larger size which has a better gravitational settling. It means that fine particles
are converted into a large one. Theoretical mechanisms are studied which led to experimental results in
155(db) and 160 (db). The results show that acoustic precipitators have a good performance in removing
fine particles in diesel exhaust. Additionally, they indicate that at high pressure levels, the system has high
efficiency for removing fine particles
A. Ghaffari, A. Khodayari, S. Arvin, F. Alimardani,
Volume 2, Issue 4 (10-2012)
Abstract
The lane change maneuver is among the most popular driving behaviors. It is also the basic element of
important maneuvers like overtaking maneuver. Therefore, it is chosen as the focus of this study and novel
multi-input multi-output adaptive neuro-fuzzy inference system models (MANFIS) are proposed for this
behavior. These models are able to simulate and predict the future behavior of a Driver-Vehicle-Unit in the
lane change maneuver for various time delays. To design these models, the lane change maneuvers are
extracted from the real traffic datasets. But, before extracting these maneuvers, several conditions are
defined which assure the extraction of only those lane change maneuvers that have a smooth and uniform
trajectory. Using the field data, the outputs of the MANFIS models are validated and compared with the
real traffic data. In addition, the result of these models is compared with the result of other trajectory
models. This comparison provides a better chance to analyze the performance of these models. The
simulation results show that these models have a very close compatibility with the field data and reflect the
situation of the traffic flow in a more realistic way.
M. Hakimollahi, S. G. Jalali Naini, M. Bagherpour, S. Jafari, A. Shahmoradi,
Volume 2, Issue 4 (10-2012)
Abstract
In recent years, the balanced score card (BSC) has been the focus of considerable methodology for strategic
cost management in management accounting area since it was originally proposed by Kaplan ,R.S. and
Norton, D.P. in 1992. BSC is an approach to performance measurement based on both financial and nonfinancial
information from four perspectives which are called financial, customer, internal business process,
and learning and growth, in order to balance the traditional financial performance system by several
grouping of performance measures: short-term and long-term, internal and external, and current and future.
Over time, it has been developed to a strategic management system from a comprehensive performance
measure, and used in many organizations such as business, hospital, and autonomy in many countries. In
this paper, we propose a general model based on BSC by introducing fuzzy inference mechanism. From
this, specialists’ knowledge and experience can be effectively reflected during the construction of the
practical model. Then we illustrate a practical example for an Automotive Manufacturing Co.
S. R. Das, D. Dhupa, A. Kumar,
Volume 3, Issue 1 (3-2013)
Abstract
Turning of hardened steels using a single point cutting tool has replaced the cylindrical grinding now as it
offers attractive benefits in terms of lower equipment costs, shorter set up time, fewer process setups,
higher material removal rate, better surface quality and elimination of cutting fluids compared to cylindrical
grinding. In order to obtain desired surface quality by machining, proper machining parameters selection is
essential. This can be achieved by improving quality and productivity in metal cutting industries. The
present study is to investigate the effect of machining parameters such as cutting speed, feed and depth of
cut on surface roughness during dry turning of hardened AISI 4340 steel with CVD
(TiN+TiCN+Al2O3+ZrCN) multilayer coated carbide inserts. A full factorial design of experiment is
selected for experimental planning and the analysis of variance (ANOVA) has been employed to analyze
the significant machining parameters on surface roughness during turning. The results showed that feed
(60.85%) is the most influencing parameter followed by cutting speed (24.6%) at 95% confidence level.
And the two-level interactions of feed-cutting speed (F*V), depth of cut-feed (D*F) and depth of cutcutting
speed (D*V) are found the significant effects on surface roughness in this turning process.
Moreover, the relationship between the machining parameters and performance measure i.e. surface
roughness has been modeled using multiple regression analysis.
S.a. Yousefsani, J. Rezaeepazhand, S.a. Maghami,
Volume 3, Issue 1 (3-2013)
Abstract
Material properties and geometry are two important design parameters which their effects should be
considered in a crashworthiness analysis. In this paper, the axial impact of metallic and hybrid energy
absorbing thin-walled tubes with poly-gonal cross-section is simulated using LS-DYNA software. The
combined effects of changing the geometry and material properties on the mass specific energy absorption
(MSEA) as well as the mean and maximum crush forces are investigated. To compare the results, all
metallic tubes have identical thickness, length, and circumference. The hybrid tubes are made of the same
metallic tubes which are reinforced with special composite overlays. These materials are intentionally
selected in such a way that the effects of yield strength and Young’s modulus can be separately
investigated. The results show that, in contrast with the current belief, there are some metallic and hybrid
tubes with non- circular cross-section shapes, which have better mass specific energy absorption
capabilities than the circular ones during the impact.
M. Azadi, M. Baloo, G. H. Farrahi, S. M. Mirsalim,
Volume 3, Issue 1 (3-2013)
Abstract
In the present paper, a complete literatures review of thermal barrier coating applications in diesel engines
is performed to select a proper type and to find coating effects. The coating system has effects on the fuel
consumption, the power and the combustion efficiency, pollution contents and the fatigue lifetime of engine
components. Usually there are several beneficial influences by applying ceramic layers on the combustion
chamber, including the piston, the cylinder head, the cylinder block, intake and exhaust valves by using a
plasma thermal spray method. Several disadvantages such as producing nitrogen oxides also exist when a
coating system is used. In this article, all effects, advantages and disadvantages of thermal barrier coatings
are investigated based on presented articles.
M.h. Shojaeefard, R. Talebitooti, S. Yarmohammadisatri, M. Torabi,
Volume 3, Issue 1 (3-2013)
Abstract
In this paper, a method based on binary-coded genetic algorithm is proposed to explore an optimization method, for obtaining an optimal elliptical tank. This optimization method enhances the rollover threshold of a tank vehicle, especially under partial filling conditions. Minimizing the overturning moment imposed on the vehicle due to c.g. height of the liquid load, lateral acceleration and cargo load shift are properly applied. In the process, the width and height of tanker are assumed as constant parameters. Additionally, considering the constant cross-sectional area, an optimum elliptical tanker of each filling condition is presented to provide more roll stability. Moreover, the magnitudes of lateral and vertical translation of the cargo within the proposed optimal cross section under a constant lateral acceleration field are compared with those of conventional elliptical tank to demonstrate the performance potentials of the optimal shapes. Comparing the vehicle rollover threshold of proposed optimal tank with that of currently used elliptical and circular tank reveals that the optimal tank is improved approximately 18% higher than conventional one.
H. Pashazadeh, A. Masoumi, J. Teimournezhad,
Volume 3, Issue 1 (3-2013)
Abstract
The objective of this study was to develop a numerical model for the prediction of temperature distribution,
effective plastic strain distribution, and especially material flow in friction stir welding of copper plates.
The DEFORM-3D software was used by incorporating a lagrangian incremental formulation. Threedimensional
results of the material flow pattern which were extracted using the point tracking are in good
agreement with the experiment. It was shown that the main part of material flow occurs near the top
surface. Material near the top surface at the behind of tool stretches from retreating side towards advancing
side which leads to non-symmetrical shape of the stir zone. The stir zone shape in FSW of copper alloys,
which was predicted by simulation, does not lean completely towards any sides of welding line.
M. A. Saeedi, R. Kazemi,
Volume 3, Issue 1 (3-2013)
Abstract
In this study, stability control of a three-wheeled vehicle with two wheels on the front axle, a three-wheeled
vehicle with two wheels on the rear axle, and a standard four-wheeled vehicle are compared. For vehicle
dynamics control systems, the direct yaw moment control is considered as a suitable way of controlling the
lateral motion of a vehicle during a severe driving maneuver. In accordance to the present available
technology, the performance of vehicle dynamics control actuation systems is based on the individual
control of each wheel braking force known as the differential braking. Also, in order to design the vehicle
dynamics control system the linear optimal control theory is used. Then, to investigate the effectiveness of
the proposed linear optimal control system, computer simulations are carried out by using nonlinear twelvedegree-
of-freedom models for three-wheeled cars and a fourteen-degree-of-freedom model for a fourwheeled
car. Simulation results of lane change and J-turn maneuvers are shown with and without control
system. It is shown that for lateral stability, the three wheeled vehicle with single front wheel is more stable
than the four wheeled vehicle, which is in turn more stable than the three wheeled vehicle with single rear
wheel. Considering turning radius which is a kinematic property shows that the front single three-wheeled
car is more under steer than the other cars.
