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Abstract A simple transient analysis of the conventional mud chullah of single pot seat has been presented. The effects of various parameters, namely pressure and non-pressure pot, use of insulation in walls and basement of the chullah, heat capacity of pot-water, burning rate of wood, and heat losses from the combustion gas, have been incorporated in the analysis. Keeping in view the outcomes of this analysis, some interesting recommendations have been made to make the mud chullah more efficient.

Abstract A simple transient analysis of the conventional mud chullah of single pot seat has been presented. The effects of various parameters, namely pressure and non-pressure pot, use of insulation in walls and basement of the chullah, heat capacity of pot-water, burning rate of wood, and heat losses from the combustion gas, have been incorporated in the analysis. Keeping in view the outcomes of this analysis, some interesting recommendations have been made to make the mud chullah more efficient.

Abstract Recently, biodiesel has been gaining market share against fossil-origin diesel due to its ecological benefits and because it can be directly substituted for traditional diesel oils. However, the high cost of the raw materials required to produce biodiesel make it more expensive than fossil diesel. Therefore, low-priced raw materials, such as waste cooking oil and animal fats, are of interest because they can be used to drive down the cost of biodiesel. We have produced biodiesel from camel fat using a transesterification reaction with methanol in the presence of NaOH. The experimental variables investigated in this study were the temperature (30–75 °C), reaction time (20–160 min), catalyst concentration (0.25–1.5%), and methanol/fat molar ratio (4:1–9:1). A maximum biodiesel yield of 98.6% was obtained. The fuel properties of biodiesel, such as iodine value, saponification value, density, kinematic viscosity, cetane number, flash point, sulfur content, carbon residue, water and sediment, high heating value, refractive index, cloud point, pour point, and distillation characteristics, were measured. The properties were compared with EN 14214 and ASTM 6751 biodiesel standards, and an acceptable level of agreement was obtained.

Abstract Recently, biodiesel has been gaining market share against fossil-origin diesel due to its ecological benefits and because it can be directly substituted for traditional diesel oils. However, the high cost of the raw materials required to produce biodiesel make it more expensive than fossil diesel. Therefore, low-priced raw materials, such as waste cooking oil and animal fats, are of interest because they can be used to drive down the cost of biodiesel. We have produced biodiesel from camel fat using a transesterification reaction with methanol in the presence of NaOH. The experimental variables investigated in this study were the temperature (30–75 °C), reaction time (20–160 min), catalyst concentration (0.25–1.5%), and methanol/fat molar ratio (4:1–9:1). A maximum biodiesel yield of 98.6% was obtained. The fuel properties of biodiesel, such as iodine value, saponification value, density, kinematic viscosity, cetane number, flash point, sulfur content, carbon residue, water and sediment, high heating value, refractive index, cloud point, pour point, and distillation characteristics, were measured. The properties were compared with EN 14214 and ASTM 6751 biodiesel standards, and an acceptable level of agreement was obtained.

The applications of anhydrous bioethanol to substitute or replace gasoline fuel have shown to attain benefits in terms of engine thermal efficiency, power output and exhaust emissions from spark ignition engines. A hydrous bioethanol has also been gained more attention due to its energy and cost effectiveness. The main aim of this work is to minimize fuel quantity injected to the intake ports of a four-cylinder engine under idle condition. The engine running with hydrous ethanol undergoes within lean-burn condition as its combustion stability is analyzed using an engine indicating system. Coefficient of variation in indicated mean effective pressure is an indicator for combustion stability with hydrocarbon and carbon monoxide emission monitoring as a supplement. Anhydrous ethanol burns faster than hydrous ethanol and gasoline in the uncalibrated engine at the same fuel-to-air equivalence ratio under idle condition. The leaner hydrous ethanol combustion tends to elevate the coefficient of variation in indicated mean effective pressure. The experimental results have found that the engine consumes greater hydrous ethanol by 10% on mass basis compared with those of anhydrous ethanol at the lean limit of fuel-to-air equivalence ratio of 0.67. The results of exhaust gas analysis were compared with those predicted by chemical equilibrium analysis of the fuel-air combustion; the resemble trends were found. Calibrating the alternative fueled engine for fuel injection quantity should be accomplished at idle with combustion stability and emissions optimization.

The applications of anhydrous bioethanol to substitute or replace gasoline fuel have shown to attain benefits in terms of engine thermal efficiency, power output and exhaust emissions from spark ignition engines. A hydrous bioethanol has also been gained more attention due to its energy and cost effectiveness. The main aim of this work is to minimize fuel quantity injected to the intake ports of a four-cylinder engine under idle condition. The engine running with hydrous ethanol undergoes within lean-burn condition as its combustion stability is analyzed using an engine indicating system. Coefficient of variation in indicated mean effective pressure is an indicator for combustion stability with hydrocarbon and carbon monoxide emission monitoring as a supplement. Anhydrous ethanol burns faster than hydrous ethanol and gasoline in the uncalibrated engine at the same fuel-to-air equivalence ratio under idle condition. The leaner hydrous ethanol combustion tends to elevate the coefficient of variation in indicated mean effective pressure. The experimental results have found that the engine consumes greater hydrous ethanol by 10% on mass basis compared with those of anhydrous ethanol at the lean limit of fuel-to-air equivalence ratio of 0.67. The results of exhaust gas analysis were compared with those predicted by chemical equilibrium analysis of the fuel-air combustion; the resemble trends were found. Calibrating the alternative fueled engine for fuel injection quantity should be accomplished at idle with combustion stability and emissions optimization.

Abstract Fuel properties play important roles both in the physical process of fuel air mixing and chemical process of combustion in the cylinder of diesel engines. There are many parameters to represent physical and chemical properties of a diesel fuel, which may affect combustion of diesel engine to different degrees. It is valuable to deeply understand the effects of fuel properties and the relations between some major properties as well. Therefore, the effects of diesel fuel properties on combustion and emissions have been experimentally investigated on a heavy-duty diesel engine in this study. In addition, the relationships among some major properties have been discussed. Twelve fuels with different fuel properties, which were produced by different refining processes from different refineries in China, were selected to ensure that the tested fuels have a wide representative. The results show that there is a strong correlation between fuel density and other fuel properties such as cetane number, aromatic hydrocarbon fraction, heat value, etc. Especially, the linear regression model between density and cetane number shows a certain reference significance. The cetane number of fuel with high density is low, which results in the delay of combustion and the rise of peak heat release rate at low load. There is no significant difference in brake thermal efficiency (BTE) for fuels with different fuel properties in the current study. However, the brake specific fuel consumption (BSFC) increases with the increase of fuel density because of the decrease in heat value. As the fuel density increases, the NOx emissions increase accordingly and the soot emissions roughly show an increasing trend as well. At low load, both CO and HC emissions obviously increase with the increase of fuel density. For example, at low load and low speed, CO and HC increase by 256%, 158% respectively as the fuel density increases from 800 kg/m3 to 920 kg/m3. Nonetheless, CO emissions remain a low level and show no obvious changes at medium and high loads, which is different from HC emissions that increase gradually especially for high speed conditions. The results of the European Steady-state Cycle (ESC) show that weighted BSFC and weighted emissions exhibit strong correlations with fuel density. When fuel density is bigger than a certain value (about 845 kg/m3), a rapid increasing trend is presented in the emissions of NOx, soot, CO and HC.