(3) At the ignition temperature the evolved gases are too rich, at first, in carbon dioxide and water vapor to sustain flame very long. However, the heat of the flame starts a secondary pryolysis reaction process and flaming combustion occurs entirely in the gaseous distillate vapor phase. Gas evolution may be so fast that it blankets the fuel surface and excludes air. This prevents the char from burning, retards the penetration of heat, and delays the temperatures in penetrat- ing deeper into the material. As tem- peratures increase, the char begins to glow, air flows in to support combustion, and the fuel itself burns as well as its decomposition gases. If the released heat is concentrated and sufficient to sus- tain oxidation, and more heat is generated than lost through conduction, convection, or radiation, a positive heat balance exists. If, however, most or all of the heat generated is lost, there is a negative heat balance and the fire goes out as a match flame in a wind. At the same time, a condi- tion known as feedback may exist. Feedback is generated heat that prepares adjacent combusti- ble material for burning by raising it to ignition temperatures. If the feedback is not adequate, the fire goes out. In addition to heat generation dur- ing pyrolysis, the concentration of the oxidizing agent is another factor that determines whether or not ignition and combustion can occur. There appears to be a minimal oxidizing agent concen- tration for almost all materials below which com- bustion will not take place. Exceptions to the lat- ter are some combustible solids, such as cellulose nitrate, that contain oxygen in the constituent molecules. This oxygen can be released by heat even if there is no air supply. Thus,
From Fig. 4, we obtained the B0-B100 of the kinematic viscosity average values range from 3.14 mm 2 /s to 4.35 mm 2 /s. Generally, the biodiesel would be a fuel for a diesel engine. The kinematic viscosity range followed the ASTM D6751 and EN 14214 specification standards [23, 24], from 1.9 mm 2 /s to 6 mm 2 /s and from 3.5 mm 2 /s to 5.0 mm 2 /s, respectively. It was too thin for B2-B10 as a blend biodiesel for EN 14214 specification standards, and it could not provide the appropriate lubrication of diesel engines. We also observed that B20-B100 (3.51-4.35 mm 2 /s), whose values of kinematic viscosity were included in a suitable range, was also concerned with the effective fuel for diesel engine, such as the winterization, the heat of combustion, the f lash point, and the storage conditions of blend biodiesel (see Fig . 4). Then, the best conditions of the mixtures were obtained as an available blend biodiesel in this study.
Abstract-Engine gets its power due to combustion of the fuel in its cylinder. Due to the combustion process the temperature of the cylinder wall is increased to a very high degree and here the coolant temperature comes to rescue by taking the heat from the cylinder wall to the outside atmosphere. Temperature of the exhaust plays an important role by giving an idea of the functioning of various engine parts and engine as a whole. With increase in the load the exhaust temperature increases and hence coolant temperature. Here the ratio of the exhaust temperature to the coolant temperature gives idea of the ability of coolant to take away heat from the cylinder wall at increases load. Higher the ratio means less effective cooling of the cylinder wall and hence decreased life of engine.
An effective LHS system, using a PCM with melting temperature within 100-150 °C, can flatten out the peak heat release to the room by storing it as latent heat. The stored heat can then be released to the room at the end of the batch combustion, through a relatively stable heat release over an extended time-period. Compared to current sensible heat storage solutions using e.g. soapstone, PCMs have the potential to yield a more efficient solution. For a given temperature range, PCM offer higher heat storage capacity both per unit mass and volume, as well as a more stable heat release due to the quasi-isothermal phase change process. These advantages are of special interest for highly- insulated low-energy buildings and passive houses. LHS systems may be designed as a retrofit to existing wood stoves or as an integrated and optimized add-on to new wood stoves. However, designing an optimal system with a suitable PCM remains challenging due to the complexity of the physical and thermal interactions between PCM, heat source and heat sink and the transient nature of wood stoves.
Carbon monoxide (Fig. 3), the product of incom- plete combustion, at every examined sample of fuel and the combustion equipment in the dependence on the coefficient of excess air at first in the area with a very low coefficient of excess air is decreas- ing down to the optimal values, but after the opti- mal values of the coefficient of excess air have been exceeded there occurs gradual increase of carbon monoxide up to the maximum concentration. This process can be observed at all fuels except for pop- lar pellets at the combustion equipment with lower fuel supply and lucerne pellets and oats at the com- bustion equipment with gravity stoking when at these measurements from the beginning the car- bon monoxide is gradually increasing. The reason why a different process of combustion occurs at the fuel samples can be attributed to multiple factors such as the calorific value, the proportion of vola- tile matter in the sample and the volume of com- bustion air brought into the combustion chamber. Also in the combustion equipment an insufficient mixing of volatile flammable substances can occur with the combustion air, and thus an insufficient fire penetration on the refractory retorts.
called ―the Efficiency Rule‖, a separate set of relationships, of: Brake, indicated Power, indicated and mean effective pressures, indicated and brake specific fuel consumptions, as functions of the energy efficiencies of: thermal, volumetric, combustion, and mechanical efficiencies, and other engine parameters. Pirouz-Panah and Asadi  conducted computer-aided performance predictions of dual-fuel Diesel engines constructed with thermodynamic models of Diesel, blended separately with Liquefied Petroleum Gas (LPG) and Compressed Natural Gas (CNG) with reference to engine cycles, and in particular based on limited-pressure cycle, and the result compared to the performance of an engine operating on Diesel only fuel. Pirouz-Panah and Asadi  concluded that, increased gas proportion in dual-fuel engines results in higher indicated power, and indicated mean effective pressure, and thus, more work done per cycle of engine operation, with better fuel economy, without appreciable change in thermal efficiency. In a similar but experimental approach Pirouz- Panah, Sarabchi and Kosha  carried out experimental investigations and engine performance studies on a dual fuel (LPG-Diesel blend) direct injection diesel engine under various load conditions. The work showed that with equal power, the LPG-diesel fuel engines had better performance with improved fuel economy, and reduced emissions. They also investigated different proportions of LPG-Diesel blend and concluded that the optimal blend is 30 % LPG-70% Diesel. Ajav and Akingbehin  in an experimental study on some fuel properties of ethanol extracted from Nigerian sugarcane, blended with diesel fuel to determine suitability for use in compression-ignition engines, established that Diesel-ethanol blends containing 5-, 10-, 15-, and 20
The Indian foundry produces around 6 million ton of castings annually. The slag generated annually is around 1.8 million ton. The slag produced in an ore refining or smelting process of a blast furnace, is almost 30 % of metal produce, and at a temperature @ 1150 0 C. The heat energy is carried away by slag is proportional to its temperature and quantity.
Piston rings are commonly made from cast iron. Cast iron retains the integrity of its original shape under heat, load, and other dynamic forces. Piston rings seal the combustion chamber, conduct heat from the piston to the cylinder wall, and return oil to the crankcase. Piston ring size and configuration vary depending on engine design and cylinder material. Some piston rings have a chamfered edge opposite the running surface. This chamfered edge causes the piston ring to twist when not affected by combustion gas pressures. The piston rings acts as the movable end of the combustion chamber and must withstand thermal stress, and mechanical load. Piston ring materials and design contribute to the overall durability and performance of an engine. Most pistons are made from die- or gravity-cast aluminum alloy. Cast aluminum alloy is lightweight and has good structural integrity and low manufacturing costs. The light weight of aluminum reduces the overall mass and force necessary to initiate and maintain acceleration of the piston. This allows the piston to utilize more of the force produced by combustion to power the application.
Hidehiko Kajiwaraa, Yukihiro Fujiokab, Tatsuya Suzukia, Hideo NegishiUsing CFD tools to calculate the coefficient of heat transfer for the cooling gallery, which is influential in piston cooling. J.H. Ong  using the results of a finite element analysis for the prediction of the steady state temperature distribution in a high speed diesel engine piston.V. Esfahanian, A. Javaheri, M. Ghaffarpour  calculates the heat transfer to an engine piston crown. Three different methods for the combustion boundary condition are used. The results of different combustion side boundary condition treatments are compared and their effects on the thermal behavior of the piston are investigated. H.W. Wu, C.P. Chiu study presents a finite element heat transfer model for the prediction of piston temperature distributions in a
Oil palm biomass wastes emerge as a potentially major contribution to renewable energy as the Malaysian government has now shifted from conventional sources such as coal, oil, and gas to promoting renewable energy sources in order to increase energy security. Indeed the combustion of fossil fuels’ as sources of energy for heat, transportation, and electricity is known to be the major factor contributing to global warming. The world is moving from the conventional non-renewable energy sources to renewable energy sources due to their renewability and eco-friendly nature, which is critical for the future generation of power. The Malaysian government has made several efforts to encourage the use of renewable energy to scale down dependency on fossil fuels and to meet the growing demand for energy. As a result, the Fifth Fuel Policy was introduced in 2001 to encourage new renewable energy sources such as oil palm, rice husk, and wood waste to compliment the conventional energy supply . The adoption of this fifth-fuel policy was supported by the implementation of small renewable energy power (SREP) . Sarawak, one of the largest town in Malaysia has the potential to generate a total of 425 MW of electricity from biomass sources, where 375 MW of this amount was contributed by palm biomass. In Nigeria, most of the electricity generated is from gas-fired thermal power plant which uses several methods in its conversion. One of the methods is burning the gas in a boiler to produce steam, which is then used by a steam turbine to generate electricity. This has led to the over- dependence on conventional oil, which in turn has led to gas flaring. Agricultural biomass can be converted to useful products. Over- dependence on hydropower and steam turbine in Nigeria has made this biomass to be underutilized. Considerable research and development are currently ongoing to develop smaller gas fires that would produce electricity on a small scale. Currently, biomass is used for off-
The compression ignition engines are widely used due to its reliable operation and economy. As the petroleum reserves are depleting at a faster rate due to the growth of population and the subsequent energy utilization, engine performance, heat release pattern engine emission characteristic need to be improved. The increasing use of diesel combustion for powering automobiles has led to considerable activity in methods for the reduction of particulate emissions. Diesel engines are one of the major contributors to the emissions such a hydrocarbons, particulates, nitrogen oxides, and Sulphur oxides. These emissions are very harmful to human beings and also responsible for acid rain and photochemical contamination and hence subject to strict environmental legislation (12). Efforts were also made for the reformulation of diesel fuel to reduce these harmful emissions without changing the physicochemical properties of fuel such
Figure 3 shows graph between brake power (bp) and coolant water temperature (T2) at part load. It is seen from the graph that bp tends to increase with temperature from 50˚C. This is because the higher wall temperature delays flame quenching on the wall as the quench layer thickness gets reduced and hence the bp increases. The maximum bp occurs at around 65 ˚C-75˚C for all test fuels considered. With diesel the maximum bp is 2.36 kW at 65˚C and at 75 ˚C while with biodiesel the maximum bp is 2.18 kW at 75 ˚C. Beyond 75 ˚C the bp reduces. This is attributed to the fact that volumetric efficiency (ηv) reduces with increase in operating temperature due to the decrease in air density at higher temperature . It is also seen from the figure that the increase of biodiesel percentage in the blends (B40 and B100) resulted in a decrease of bp over the entire temperature range. This is due to the fact that the higher viscosity and lower heating value of Jatropha oil methyl ester reduces bp. The higher viscosity results in power losses, because the higher viscosity decreases combustion efficiency due to poor fuel injection atomization. It was also found that the B20, B10 and B0 have almost similar bp values. This could be attributed to additional lubricity and presence of oxygen provided by the biodiesel in blends B20 and B10 resulting improved combustion and mitigates the effect of higher viscosity and lower heating value of biodiesel.
As mentioned earlier, stepped piston refers to the mating of two pistons to form an assembly. For this work, the main piston has an aspect ratio (bore:height) of 1:1.5. The bigger piston coupled to the main piston has an aspect ratio of 7.5:1. Each of these piston sections has a set of piston rings to prevent the air–fuel mixture from crossing over from the upper half to the lower half of the pistons or vice versa. The second piston has an aspect ratio of more than 2 and its only role is to draw in the mixture (air–fuel–lube) when the piston goes through the expansion stroke. In other words, for one cycle, the cylinder will undergo two main processes, i.e., 1) combustion/exhaust and expansion, and 2) compression and transfer, respectively. The piston motion is similar to the conventional design but without the crankcase scavenging normally associated with typical two-stroke engines. In other words, this design shortens the travelling path of the mixture into the combustion chamber. The design is shown in Figure 2.
Energy crisis and Thermal energy management are the burning issues of present scenario .As we know that a major part of the heat supplied in an Internal combustion engine is not realized as work output, but dumped into the atmosphere as waste heat so it becomes crucial to recover this waste heat. This study shows the crucial role that Thermo electric generator plays for heat recovery from an Internal combustion engine .Thermo electric generators are solid state devices that are used to convert Thermal energy from a Temperature gradient to Electrical energy. In this way we can say that Thermoelectric generators may play an important role by enhancing the overall efficiency of an Internal combustion engine as they help in tapping and converting this waste heat energy into usable energy.
The results from the quasi-steady modelling showed that no agreement was achieved between the measured and the simulated heat flux using the scaled Eichelberg’s model for the motored case and the scaled Woschni’s model for the fired case. A significant improvement in the simulation of the heat flux measure- ments was achieved when the unsteady energy equation modelling of the thermal boundary layer was applied. The simulation results have only a small sensitiv- ity to the boundary layer thickness. The simulated heat flux using the unsteady model with one particular turbulent Prandtl number model, agreed with mea- sured heat flux in the wide open throttle and fully closed throttle cases, with an error in peak values of about 6 % and 35 % for those cases respectively. In the fired case, a good agreement was also observed from the unsteady model and the error in the peaks between the measured and the simulated heat flux was found to be about 9 %.
The various methods like EGR, catalytic converters, retarding the injection timing, use of high injection pressure, split injection and modifying the combustion chamber geometry to enhance the swirl and squish are being evaluated to reduce emissions but problems are still prevailing in the operation of these techniques. In an attempt to meet such standards the various alternative fuels such as Methanol, Ethanol, Natural gas dual fuel, Biodiesel etc. have been tried in CI engines worldwide [19,23].