Abstract: In this study, effects of EGR on CO and HC emissions
of a dual fuel HCCI-DI engine are investigated. Tests were
conducted on a single-cylinder variable compression ratio (VCR)
diesel engine with compression ratio of 17.5. Premixed gasoline is
provided by a carburetor connected to intake manifold and equipped
with a screw to adjust premixed air-fuel ratio, and diesel fuel is
injected directly into the cylinder through an injector at pressure of
250 bars. A heater placed at inlet manifold is used to control the
intake charge temperature. Optimal intake charge temperature was
110-115ºC due to better formation of a homogeneous mixture
causing HCCI combustion. Timing of diesel fuel injection has a great
effect on stratification of in-cylinder charge in HCCI combustion.
Experiments indicated 35 BTDC as the optimum injection timing.
Coolant temperature was maintained 50ºC during the tests. Results
show that increasing engine speed at a constant EGR rate leads to
increase in CO and UHC emissions due to the incomplete
combustion caused by shorter combustion duration and less
homogeneous mixture. Results also show that increasing EGR
reduces the amount of oxygen and leads to incomplete combustion
and therefore increases CO emission due to lower combustion
temperature. HC emission also increases as a result of lower
combustion temperatures.
Abstract: One of the best ways for achievement of conventional
vehicle changing to hybrid case is trustworthy simulation result and
using of driving realities. For this object, in this paper, at first sevendegree-
of-freedom dynamical model of vehicle will be shown. Then
by using of statically model of engine, gear box, clutch, differential,
electrical machine and battery, the hybrid automobile modeling will
be down and forward simulation of vehicle for pedals to wheels
power transformation will be obtained. Then by design of a fuzzy
controller and using the proper rule base, fuel economy and
regenerative braking will be marked. Finally a series of
MATLAB/SIMULINK simulation results will be proved the
effectiveness of proposed structure.
Abstract: The bonding configuration and the heat of adsorption
of a furfural molecule on the Pd(111) surface were determined by ab
initio density-functional-theory calculations. The dynamics of pure
liquid water, the liquid-solid interface formed by liquid water and the
Pd(111) surface, as well as furfural at the water-Pd interface, were
investigated by ab initio molecular dynamics simulations at finite
temperatures. Calculations and simulations suggest that the bonding
configurations at the water-Pd interface promote decarbonylation of
furfural.
Abstract: This paper presents the solution of power economic dispatch (PED) problem of generating units with valve point effects and multiple fuel options using Self-Adaptive Differential Evolution (SDE) algorithm. The global optimal solution by mathematical approaches becomes difficult for the realistic PED problem in power systems. The Differential Evolution (DE) algorithm is found to be a powerful evolutionary algorithm for global optimization in many real problems. In this paper the key parameters of control in DE algorithm such as the crossover constant CR and weight applied to random differential F are self-adapted. The PED problem formulation takes into consideration of nonsmooth fuel cost function due to valve point effects and multi fuel options of generator. The proposed approach has been examined and tested with the numerical results of PED problems with thirteen-generation units including valve-point effects, ten-generation units with multiple fuel options neglecting valve-point effects and ten-generation units including valve-point effects and multiple fuel options. The test results are promising and show the effectiveness of proposed approach for solving PED problems.
Abstract: By the application of an improved back-propagation
neural network (BPNN), a model of current densities for a solid oxide
fuel cell (SOFC) with 10 layers is established in this study. To build
the learning data of BPNN, Taguchi orthogonal array is applied to
arrange the conditions of operating parameters, which totally 7 factors
act as the inputs of BPNN. Also, the average current densities
achieved by numerical method acts as the outputs of BPNN.
Comparing with the direct solution, the learning errors for all learning
data are smaller than 0.117%, and the predicting errors for 27
forecasting cases are less than 0.231%. The results show that the
presented model effectively builds a mathematical algorithm to predict
performance of a SOFC stack immediately in real time.
Also, the calculating algorithms are applied to proceed with the
optimization of the average current density for a SOFC stack. The
operating performance window of a SOFC stack is found to be
between 41137.11 and 53907.89. Furthermore, an inverse predicting
model of operating parameters of a SOFC stack is developed here by
the calculating algorithms of the improved BPNN, which is proved to
effectively predict operating parameters to achieve a desired
performance output of a SOFC stack.
Abstract: Some of the polycyclic aromatic hydrocarbons (PAHs)
are the strongest known carcinogens compounds; the majority of
them are mostly produced by the incomplete combustion of fossil
fuels; Motor vehicles are a significant source of polycyclic aromatic
hydrocarbon (PAH) where diesel emission is one of the main sources
of such compounds available in the ambient air. There is a big
concern about the increasing concentration of PAHs in the
environment. Researchers are trying to explore optimal methods to
reduce those pollutants and improve the quality of air. Water blended
fuel is one of the possible approaches to reduce emission of PAHs
from the combustion of diesel in urban and domestic vehicles. In this
work a modeling study was conducted using CHEMKIN-PRO
software to simulate spray combustion at similar diesel engine
conditions. Surrogate fuel of (80 % n-heptane and 20 % toluene) was
used due to detailed kinetic and thermodynamic data needed for
modeling is available for this kind of fuel but not available for diesel.
An emulsified fuel with 3, 5, 8, 10 and 20 % water by volume is used
as an engine feed for this study. The modeling results show that water
has a significant effect on reducing engine soot and PAHs precursors
formation up to certain extent.
Abstract: Automotive engine air-ratio plays an important role of
emissions and fuel consumption reduction while maintains
satisfactory engine power among all of the engine control variables. In
order to effectively control the air-ratio, this paper presents a model
predictive fuzzy control algorithm based on online least-squares
support vector machines prediction model and fuzzy logic optimizer.
The proposed control algorithm was also implemented on a real car for
testing and the results are highly satisfactory. Experimental results
show that the proposed control algorithm can regulate the engine
air-ratio to the stoichiometric value, 1.0, under external disturbance
with less than 5% tolerance.
Abstract: In this study, oxidative steam reforming of methanol (OSRM) over a Au/CeO2–Fe2O3 catalyst prepared by a depositionprecipitation (DP) method was studied to produce hydrogen in order to feed a Proton Exchange Membrane Fuel Cell (PEMFC). The support (CeO2, Fe2O3, and CeO2–Fe2O3) were prepared by precipitation and co-precipitation methods. The impact of the support composition on the catalytic performance was studied by varying the Ce/(Ce+Fe) atomic ratio, it was found that the 1%Au/CF(0.25) calcined at 300 °C exhibited the highest catalytic activity in the whole temperature studied. In addition, the effect of Au content was investigated and 3%Au/CF(0.25) exhibited the highest activity under the optimum condition in the temperature range of 200 °C to 400 °C. The catalysts were characterized by various techniques: XRD, TPR, XRF, and UV-vis.
Abstract: Movable power sources of proton exchange
membrane fuel cells (PEMFC) are the important research done in the
current fuel cells (FC) field. The PEMFC system control influences
the cell performance greatly and it is a control system for industrial
complex problems, due to the imprecision, uncertainty and partial
truth and intrinsic nonlinear characteristics of PEMFCs. In this paper
an adaptive PI control strategy using neural network adaptive Morlet
wavelet for control is proposed. It is based on a single layer feed
forward neural networks with hidden nodes of adaptive morlet
wavelet functions controller and an infinite impulse response (IIR)
recurrent structure. The IIR is combined by cascading to the network
to provide double local structure resulting in improving speed of
learning. The proposed method is applied to a typical 1 KW PEMFC
system and the results show the proposed method has more accuracy
against to MLP (Multi Layer Perceptron) method.
Abstract: In this paper, the residual stress of thermal spray
coatings in gas turbine component by curvature method has been
studied. The samples and shaft were coated by hard WC-12Co
cermets using high velocity oxy fuel (HVOF) after preparation in
same conditions. The curvature of coated samples was measured by
using of coordinate measurement machine (CMM). The metallurgical
and Tribological studies has been made on the coated shaft using
optical microscopy and scanning electron microscopy (SEM)
Abstract: We successfully developed and tested a new
separation layer solving problems with unmanageable deposits inside the boilers of Zluticka Heating Plant. The deposits are mainly created
by glass-forming melts. We plotted straw ash compositions in K2OCaO-
SiO2 phase diagram and illustrated that they are in the area of low-melting eutectic points. To prevent the melting of ash and the
formation of deposits, we modified ash compositions by injecting additives into biomass fuel, and thus effectively suppressed deposits in a burner.
Abstract: The combustion chamber dimensions have important
effects on pollutant emission in furnaces as a direct result of
temperature distribution and maximum temperature value. In this
paper the pollutant emission and the temperature distribution in two
cylindrical furnaces with different dimensions (with similar length to
diameter ratio) in similar condition have been investigated
experimentally. The furnace fuel is gas oil that is used with three
different flow rates. The results show that in these two cases the
temperature increases to its maximum value quickly, and then
decreases slowly. The results also show that increase in fuel flow rate
cause to increase in NOx emission in each case, but this increase is
greater in small furnace. With increase in fuel flow rate, CO emission
decreases firstly, and then it increases. Combustion efficiency
reduces with increase in fuel flow rate but the rate of reduction in
small furnace is greater than large furnace. The results of axial
temperature distribution have been compared with those have been
obtained numerically and experimentally by Moghiman.
Abstract: The evaluation of unit cell neutronic parameters and
lifetime for some innovant reactors without on sit-refuling will be
held in this work. the behavior of some small and medium reactors
without on site refueling with triso and cermet fuel. For the FBNR
long life except we propose to change the enrichment of the Cermet
MFE to 9%. For the AFPR reactor we can see that the use of the
Cermet MFE can extend the life of this reactor but to maintain the
same life period for AFPR-SC we most use burnup poison to have the
same slope for Kinf (Burnup). PFPWR50 cell behaves almost in
same way using both fuels Cermet and TRISO. So we can conclude
that PFPWR50 reactor, with CERMET Fuel, is kept among the long
cycle reactors and with the new configuration we avoid subcriticality
at the beginning of cycle. The evaluation of unit cell neutronic
parameters reveals a good agreement with the goal of BWR-PB
concept. It is found out that the Triso fuel assembly lifetime can be
extended for a reasonably long period without being refueled,
approximately up to 48GWd/t burnup. Using coated particles fuels
with the Cermet composition can be more extended the fuel assembly
life time, approximately 52 GWd/t.
Abstract: The accelerated growth in aircraft industries desire
effectual schemes, programs, innovative designs of advanced systems
to accomplishing the augmenting need for home-free air
transportation. In this paper, a contemporary conceptual design of an
airplane has been proposed without landing gear systems in order to
reducing accidents, time consumption, and to eliminating drawbacks
by using superconducting levitation phenomenon. This invention of
an airplane with superconductive material coating, on the solar plexus
region assist to reduce weight by approximately 4% of the total takeoff
weight, and cost effective. Moreover, we conjectured that
superconductor landing system reduces ground friction, mission fuel,
total drag, take-off and landing distance.
Abstract: In this paper, a fuzzy algorithm and a fuzzy multicriteria
decision framework are developed and used for a practical
question of optimizing biofuels policy making. The methodological
framework shows how to incorporate fuzzy set theory in a decision
process of finding a sustainable biofuels policy among several policy
options. Fuzzy set theory is used here as a tool to deal with
uncertainties of decision environment, vagueness and ambiguities of
policy objectives, subjectivities of human assessments and imprecise
and incomplete information about the evaluated policy instruments.
Abstract: It was determined that woody biomass and livestock excreta can be utilized as hydrogen resources and hydrogen produced from such sources can be used to fill fuel cell vehicles (FCVs) at hydrogen stations. It was shown that the biomass transport costs for hydrogen production may be reduced the costs for co-generation. In the Tokyo Metropolitan Area, there are only a few sites capable of producing hydrogen from woody biomass in amounts greater than 200 m3/h-the scale required for a hydrogen station to be operationally practical. However, in the case of livestock excreta, it was shown that 15% of the municipalities in this area are capable of securing sufficient biomass to be operationally practical for hydrogen production. The differences in feasibility of practical operation depend on the type of biomass.
Abstract: As the demand and prices of various petroleum products have been on the rise in recent years, there is a growing need for alternative fuels. Biodiesel, which consists of alkyl monoesters of fatty acids from vegetable oils and animal fats, is considered as an alternative to petroleum diesel. Biodiesel has comparable performance with that of diesel and has lower brake specific fuel consumption than diesel with significant reduction in emissions of CO, hydrocarbons (HC) and smoke with however, a slight increase in NOx emissions. This paper analyzes the effect of cooled exhaust gas recirculation in the combustion characteristics of a direct injection compression ignition engine using biodiesel blended fuel as opposed to the conventional system. The combustion parameters such as cylinder pressure, heat release rate, delay period and peak pressure were analyzed at various loads. The maximum cylinder pressure reduces as the fraction of biodiesel increases in the blend the maximum rate of pressure rise was found to be higher for diesel at higher engine loads.
Abstract: This paper present an efficient and reliable technique of optimization which combined fuel cost economic optimization and emission dispatch using the Sigmoid Decreasing Inertia Weight Particle Swarm Optimization algorithm (PSO) to reduce the cost of fuel and pollutants resulting from fuel combustion by keeping the output of generators, bus voltages, shunt capacitors and transformer tap settings within the security boundary. The performance of the proposed algorithm has been demonstrated on IEEE 30-bus system with six generating units. The results clearly show that the proposed algorithm gives better and faster speed convergence then linearly decreasing inertia weight.
Abstract: This paper puts forward one kind of air-fuel ratio
control method with PI controller. With the help of
MATLAB/SIMULINK software, the mathematical model of air-fuel
ratio control system for distributorless CNG engine is constructed.
The objective is to maintain cylinder-to-cylinder air-fuel ratio at a
prescribed set point, determined primarily by the state of the Three-
Way-Catalyst (TWC), so that the pollutants in the exhaust are
removed with the highest efficiency. The concurrent control of airfuel
under transient conditions could be implemented by Proportional
and Integral (PI) controller. The simulation result indicates that the
control methods can easily eliminate the air/fuel maldistribution and
maintain the air/fuel ratio at the stochiometry within minimum
engine events.
Abstract: Importance of environmental efficiency of electric power industry stems from high demand for energy combined with global warming concerns. It is especially essential for the world largest economies like that of the United States. The paper introduces a Data Envelopment Analysis (DEA) model of environmental efficiency using indicators of fossil fuels utilization, emissions rate, and electric power losses. Using DEA is advantageous in this situation over other approaches due to its nonparametric nature. The paper analyzes data for the period of 1990 - 2006 by comparing actual yearly levels in each dimension with the best values of partial indicators for the period. As positive factors of efficiency, tendency to the decline in emissions rates starting 2000, and in electric power losses starting 2004 may be mentioned together with increasing trend of fuel utilization starting 1999. As a result, dynamics of environmental efficiency is positive starting 2002. The main concern is the decline in fossil fuels utilization in 2006. This negative change should be reversed to comply with ecological and economic requirements.