100 research outputs found
Emissions and fuel economy for a hybrid vehicle
No full textConventional vehicles play a big role in city transportation all over the world. These vehicles run on energy obtained from fossils fuels such as petroleum oils that pollute environment with the gases that are emitted after burning. In addition, the cost of this fuel type will increase because of decreasing reserves; therefore, these petroleum oils must be used very efficiently. Due to environmental and financial problems, the development of clear and efficient city transportation has accelerated. Hence, hybrid electrical vehicles gain significant importance because they are environmentally friendly and efficient in fuel usage. In this study, a conventional commercial vehicle was chosen for design to a mixed hybrid systems. A simulation program was created for road simulation of these vehicles and with acceleration included; the consumption and emission values were also approximately calculated. As a result, it was seen that the mixed hybrid vehicles possess the same performance values with low fuel and CO2 emission. (C) 2013 Elsevier Ltd. All rights reserved
An Analysis of Residual Stresses in Thermal Barrier Coatings: A FE Performance Assessment
No full textInternal combustion engines have been widely used for past 100 years. In the development of engine components a number of special techniques are used to compact the hostile operating environment, which usually includes high and cyclic forces, high and cyclic temperatures, sliding and often corrosion and/or erosion. In this study, 3-D finite element structural and thermal analyses were carried out on both uncoated (without coating) and ceramic-coated engine piston. A 150 mu m super alloy bond coating (NiCrAlY) was first applied to the piston. Then, piston was covered by 350 mu m thickness of MgZrO3 as top coating. The analysis can be utilized to detect possible thermal problem spots in an engine, and to provide input data for general engine modeling and engine lubrication and wear studies
Performance and emission characteristics of a diesel engine using esters of palm olein/soybean oil blends
No full textIn this experimental study, the engine performance and exhaust emissions of a diesel direct injection engine using mixed palm olein soybean vegetable oil ethyl ester (POSEE) and methyl ester (POSME) have been examined. The results of experimental studies have shown that the torque and brake power output of an engine, which uses biodiesels, is slightly lower and specific fuel consumption is higher than in an engine using conventional diesel fuel. It has also been observed that there is a decrease in both carbon monoxide and hydrocarbon (HC) emissions, which indicates an advantage of exhaust emissions. Although methyl ester's CO(2) emissions decreased compared with those of diesel fuel, NO and NO(X) emissions were higher with the biodiesels
AN EXPERIMENTAL INVESTIGATION OF SOLID OXIDE FUEL CELL PERFORMANCE AT VARIABLE OPERATING CONDITIONS
No full textCell temperature and selection of the reactant gases are crucial parameters for the design and optimization of fuel cell performance. In this study, effect of operating conditions on the performance of solid oxide fuel cell has been investigated. Application of response surface methodology was applied to optimize operations conditions in solid oxide fuel cell. For this purpose, an experimental set-up for testing of solid oxide fuel cell has been established to investigate the effect of hydrogen, oxygen, nitrogen flow rates and cell temperature parameters on cell performance. Hydrogen flow rate, oxygen flow rate, nitrogen flow rate, and cell temperature were the main parameters considered and they were varied between 0.25 and 1 L/min, 0.5 and 1 L/min, 0 and 1 L/min, and 700-800 degrees C in the analyses, respectively. The maximum power density was found as 0.572 W/cm(2) in the experiments
Numerical study of assembly pressure effect on the performance of proton exchange membrane fuel cell
No full textThe performance of the fuel cell is affected by many parameters. One of these parameters is assembly pressure that changes the mechanical properties and dimensions of the fuel cell components. Its first duty, however, is to prevent gas or liquid leakage from the cell and it is important for the contact behaviors of fuel cell components. Some leakage and contact problems can occur on the low assembly pressures whereas at high pressures, components of the fuel cell, such as bipolar plates (BPP), gas diffusion layers (GDL), catalyst layers, and membranes, can be damaged. A finite element analysis (FEA) model is developed to predict the deformation effect of assembly pressure on the single channel PEM fuel cell in this study. Deformed fuel cell single channel model is imported to three-dimensional, computational fluid dynamics (CFD) model which is developed for simulating proton exchange membrane (PEM) fuel cells. Using this model, the effect of assembly pressure on fuel cell performance can be calculated. It is found that, when the assembly pressure increases, contact resistance, porosity and thickness of the gas diffusion layer (GDL) decreases. Too much assembly pressure causes GDL to destroy; therefore, the optimal assembly pressure is significant to obtain the highest performance from fuel cell. By using the results of this study, optimum fuel cell design and operating condition parameters can be predicted accordingly. (C) 2010 Elsevier Ltd. All rights reserved
The effect of thermal barrier coatings on diesel engine performance
No full textCeramic coatings hold significant promise in the reduction of wear and abrasion failure in reciprocating and rotary engines for transportation and stationary power. They also have application as thermal barriers to improve the efficiency of the engines, by reducing energy loss and cooling requirements. In this study, the effects of ceramic coating on the performance of the diesel engine were investigated. The research engine was a four-stroke, direct injected, six cylinder, turbo-charged and inter-cooled diesel engine. This engine was tested at different speeds and loads conditions without coating. Then, the combustion chamber surfaces, cylinder head, valves and piston crown faces were coated with ceramic materials. The layers were made of CaZrO3 and MgZrO3 and plasma coated onto the base of the NiCrAl bond coat. The ceramic-coated research engine was tested at the same operation conditions as the standard (without coating) engine. The results indicate a reduction in fuel consumption and an improving effective efficiency of the engine. (C) 2006 Elsevier B.V. All rights reserved
Experimental study of forced convective heat transfer in a different arranged corrugated channel
No full textAn experimental study of energy balance in low heat rejection diesel engine
No full textIn a conventional internal combustion engine, approximately one-third of total fuel input energy is converted to useful work. Since the working gas in a practical engine cycle is not exhausted at ambient temperature, a major part of the energy is lost with the exhaust gases. In addition, another major part of energy input is rejected in the form of heat via the cooling system. If the energy normally rejected to the coolant could be recovered instead on the crankshaft as useful work, then a substantial improvement in fuel economy would result. In this study, the effect of insulated heat transfer surfaces on diesel engine energy balance system was investigated. The research engine was a four-stroke, direct injected, six cylinder, turbocharged and inter-cooled diesel engine. This engine was tested at different speeds and load conditions without coating. Then, combustion chamber surfaces, cylinder head, valves and piston crown faces were coated with ceramic materials. Ceramic layers were made of CaZrO3 and MgZrO3 and plasma coated onto base of the NiCrAl bond coat. The ceramic-coated research engine was tested at the same operation conditions as the standard (without coating) engine. The results indicate a reduction in fuel consumption and heat losses to engine cooling system of the ceramic-coated engine. (c) 2005 Elsevier Ltd. All rights reserved
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