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Figure 10. Effect of engine load on the heat release rate versus crank angle The rate of heat release in energy per degree with the crank angle for different mass fuel injected (low, partial, and full load) for diesel engine running at 2,000 rpm is represented in Figure 10. The heat lost through convection increased due to the more injected fuel available for the conversion of chemical energy to heat energy.

Figure 10 Effect of engine load on the heat release rate versus crank angle The rate of heat release in energy per degree with the crank angle for different mass fuel injected (low, partial, and full load) for diesel engine running at 2,000 rpm is represented in Figure 10. The heat lost through convection increased due to the more injected fuel available for the conversion of chemical energy to heat energy.

Related Figures (12)

Figure 1. Dual-zone combustion model
Figure 1. Dual-zone combustion model
The in-cylinder pressure and temperature equations of burned and unburned zones are given by [16]: The mixture state is given by the following equations [18]:
The in-cylinder pressure and temperature equations of burned and unburned zones are given by [16]: The mixture state is given by the following equations [18]:
From Figure 2, the total heat loss term dQ/d@ is modelled as [19]: Figure 2. In-cylinder heat transfer process in a diesel engine 3.1 Convective heat transfer model 3. HEAT TRANSFER MODELLING
From Figure 2, the total heat loss term dQ/d@ is modelled as [19]: Figure 2. In-cylinder heat transfer process in a diesel engine 3.1 Convective heat transfer model 3. HEAT TRANSFER MODELLING
Figure 3 presents the validation curves, between the in- cylinder simulated pressure as a function of the crankshaft angle using the dual-zone model and the pressure curve measured from the test bench of a diesel engine used by Maniniyan and Sivaprakasam [26]. A good coincidence is observed between the numerical and experimental pressure, as shown in Figure 3. The error is estimated to be in 3% between them. Figure 3. Comparison between simulated and experimental in-cylinder pressure versus crank angle
Figure 3 presents the validation curves, between the in- cylinder simulated pressure as a function of the crankshaft angle using the dual-zone model and the pressure curve measured from the test bench of a diesel engine used by Maniniyan and Sivaprakasam [26]. A good coincidence is observed between the numerical and experimental pressure, as shown in Figure 3. The error is estimated to be in 3% between them. Figure 3. Comparison between simulated and experimental in-cylinder pressure versus crank angle
From Figure 4, for fixed engine speed (value of 2,000 rpm), the engine load has a large effect on the in-cylinder pressure, we see a rapid increase in the slope at the point of combustion start (10° before TDC), the pressure peak is at a crankshaft angle of about 12° after TDC. This is may due to the advanced combustion onset of the injected mass fuel. Figure 4 also shows that when the amount of fuel injected into the sombustion chamber increases by 50%, the cylinder pressure peak increases by 20%. Figure 4. Effect of engine load on cylinder pressure versus crank angle Figure 5 shows the evolution of in-cylinder gas temperature versus crank angle for a low, partial and full load at a fixed engine speed of 2000 rpm, a rapid increase in the slope of temperature at the point where combustion starts (5° before TDC), the peak of temperatures is approximately 35°, 10° and 13° CA after TDC for a low, partial and full load. If the mass fuel-injected increased by 50% (from partial to full load), the maximum cylinder temperature increased by 28 %. The reason behind this is that at full load there is more fuel in the combustion chamber, so the combustion time increases and after that the temperature increases too.
From Figure 4, for fixed engine speed (value of 2,000 rpm), the engine load has a large effect on the in-cylinder pressure, we see a rapid increase in the slope at the point of combustion start (10° before TDC), the pressure peak is at a crankshaft angle of about 12° after TDC. This is may due to the advanced combustion onset of the injected mass fuel. Figure 4 also shows that when the amount of fuel injected into the sombustion chamber increases by 50%, the cylinder pressure peak increases by 20%. Figure 4. Effect of engine load on cylinder pressure versus crank angle Figure 5 shows the evolution of in-cylinder gas temperature versus crank angle for a low, partial and full load at a fixed engine speed of 2000 rpm, a rapid increase in the slope of temperature at the point where combustion starts (5° before TDC), the peak of temperatures is approximately 35°, 10° and 13° CA after TDC for a low, partial and full load. If the mass fuel-injected increased by 50% (from partial to full load), the maximum cylinder temperature increased by 28 %. The reason behind this is that at full load there is more fuel in the combustion chamber, so the combustion time increases and after that the temperature increases too.
Figure 6 represents the variation of the in-cylinder gas temperature as a function of the crankshaft angle in the two zones (burnt and unburnt), engine speed of 2,000 rpm, injection timing angle of 15 BTDC and for two engine loads (full load and partial load). A very rapid increase in temperature of the burning zone with the start of combustion is depicted. The high burning zone temperature is responsible for the formation of NO and soot. And on the other hand, a slight change in temperature in the unburned zone. The peak
Figure 6 represents the variation of the in-cylinder gas temperature as a function of the crankshaft angle in the two zones (burnt and unburnt), engine speed of 2,000 rpm, injection timing angle of 15 BTDC and for two engine loads (full load and partial load). A very rapid increase in temperature of the burning zone with the start of combustion is depicted. The high burning zone temperature is responsible for the formation of NO and soot. And on the other hand, a slight change in temperature in the unburned zone. The peak
Figure 7 shows the variation of the total, convective, anc radiation heat transfer rates versus crank angle for partial anc full load at an engine speed of 2,000 rpm. The maximun values of the total, convective and radiation heat transfer are showed at 17° after TDC. When the mass full injectec increased by 50%, the maximum total heat transfer value increases by 25%. It has also been noticed that the maximun convective heat transfer value increases by 16%, and _ the maximum radiation heat transfer value increase by 9%. Figure 7. Effect of engine load on total, convective and radiative heat transfer rate versus crank angle
Figure 7 shows the variation of the total, convective, anc radiation heat transfer rates versus crank angle for partial anc full load at an engine speed of 2,000 rpm. The maximun values of the total, convective and radiation heat transfer are showed at 17° after TDC. When the mass full injectec increased by 50%, the maximum total heat transfer value increases by 25%. It has also been noticed that the maximun convective heat transfer value increases by 16%, and _ the maximum radiation heat transfer value increase by 9%. Figure 7. Effect of engine load on total, convective and radiative heat transfer rate versus crank angle
temperature is 1,700K, 1,600K and 1,300K at respectively full, partial and low load.
temperature is 1,700K, 1,600K and 1,300K at respectively full, partial and low load.
Figure 9 gives the variation with the crank angle of the in- cylinder simulated gas heat transfer coefficient, for various loads at an engine speed of 2,000 rpm and an injection timing angle of 15 BTDC. The heat transfer coefficient increases with increasing engine load. This is maybe due to the higher in- cylinder temperatures during the combustion period, where the heat transfer coefficient reaches its maximum value [11]. The maximum values of the heat transfer coefficient are showed at 15°, 9°, and 7° after TDC for low, partial and full load. The maximum heat transfer coefficient value would increase by 20% by increasing the mass full injected by 50% (from partial to full load).
Figure 9 gives the variation with the crank angle of the in- cylinder simulated gas heat transfer coefficient, for various loads at an engine speed of 2,000 rpm and an injection timing angle of 15 BTDC. The heat transfer coefficient increases with increasing engine load. This is maybe due to the higher in- cylinder temperatures during the combustion period, where the heat transfer coefficient reaches its maximum value [11]. The maximum values of the heat transfer coefficient are showed at 15°, 9°, and 7° after TDC for low, partial and full load. The maximum heat transfer coefficient value would increase by 20% by increasing the mass full injected by 50% (from partial to full load).
REFERENCES Figure 12 shows the evolution of internal energy and work versus crank angle for partial and full load at engine speed of 2,000 rpm. More fuel in the combustion chamber causes more energy and work to be released, and thus the engine provides more power to the vehicle. The internal energy and work increases in the combustion phase due to the increase of injected fuel. An increase in the mass full injected by 50% would increase the maximum internal energy value by 50% while the maximum work value increases by 10%. Figure 12. Effect of engine load on internal energy and work versus crank angle
REFERENCES Figure 12 shows the evolution of internal energy and work versus crank angle for partial and full load at engine speed of 2,000 rpm. More fuel in the combustion chamber causes more energy and work to be released, and thus the engine provides more power to the vehicle. The internal energy and work increases in the combustion phase due to the increase of injected fuel. An increase in the mass full injected by 50% would increase the maximum internal energy value by 50% while the maximum work value increases by 10%. Figure 12. Effect of engine load on internal energy and work versus crank angle
hand, the fresh gases gradually decreases and is cancelled out at the end of combustion. The burned fuel mass fraction increases with the mass of the fuel injected into the combustion chamber to reach its maximum value at the end of this phase, which means that all the mass of the admitted fuel is burned (No; the curves indicates that only 40% is burnt for low load and 60% for partial load, for partial load the burnt mass is higher due to availably of oxygen and the good oxygen-fuel mixture, then stabilize at this level during the expansion period. Figure 11. Effect of engine load on burned fraction versus crank angle
hand, the fresh gases gradually decreases and is cancelled out at the end of combustion. The burned fuel mass fraction increases with the mass of the fuel injected into the combustion chamber to reach its maximum value at the end of this phase, which means that all the mass of the admitted fuel is burned (No; the curves indicates that only 40% is burnt for low load and 60% for partial load, for partial load the burnt mass is higher due to availably of oxygen and the good oxygen-fuel mixture, then stabilize at this level during the expansion period. Figure 11. Effect of engine load on burned fraction versus crank angle
Related topics:
Environmental ScienceInternal Combustion EngineAutomotive EngineeringDiesel engineExhaust Gas RecirculationCombustion ChamberExternal Combustion EngineHomogeneous Charge Compression Ignition (hcci)
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