جستجوی مقالات مرتبط با کلیدواژه « انژکتور مقطع حلقوی » در نشریات گروه « مکانیک »

Injection system of a diesel engine is heart of the engine and could have significant effects on its performance. In this paper an annulus nozzle has been considered in the injection system of the Kubota V3300 diesel engine and the engine’s performance has been investigated by considering different fuel injection pressures and different pressure of the combustion chamber due to the turbocharging. Numerical results show that under turbocharging circumstances, increasing the injection pressure leads to more perfect combustion and the magnitude of SFC decreases to 0.195. Results also show that increasing the injection pressure during turbocharging lead to the increasing of engine’s power and torque and to the increasing of pollutants. It is found that in the absence of turbocharging, increasing the injection pressure leads to the increasing of SFC. It is also found that for the injection pressure equal to 60MP, SFC is equal to 0.21. Numerical results indicate that in the absence of turbocharging, increasing the injection pressure leads to the increase of the engine’s power, torque and its pollutants. Comparisons between both cases of presence and absence of turbocharging show that amount of soot in the case of turbocharging is less than its amount when the engine is naturally aspirated. These comparisons also show that NO emission in the absence of turbocharging is considerably less than generation of NO in the other case.

One of the important ways for improving performance of diesel engines is selecting of a proper and efficient fuel injection pattern. In this study six different patterns of fuel injection have been considered and performance of a diesel engine by using these patterns of fuel injection have been investigate numerically by employing AVL Fire. An annulus nozzle have been consider for the fuel injection system. It is expected that considering an annulus nozzle lead to increase of spry cone angle and proper distribution of the fuel inside the combustion chamber. Results show that employing proper and efficient patterns of fuel injection lead to increase of engine power and decrease of exhaust pollutants gases. Results also show that by employing a quasi-triangle fuel injection pattern, the diesel engine has better performance in competition with the case of using a constant fuel injection. It is found that by employing a quasi-triangle pattern of fuel injection, SFC reduces to 0.2043 kg/kJ, while the engine power increased by 27.5% and the magnitude of NO increases slightly. In the case of employing a constant-decreasing fuel injection pattern, the magnitude of SFC reduces to 0.2029kg/kJ whereas the magnitude of NO increases in comparison with the case of using constant fuel injection pattern. Numerical results show that by employing a constant-increasing pattern of fuel injection, the engine power is approximately equal to the engine’s power in the case of using a constant fuel injection pattern. But in this case the magnitude of NO reduces considerably.