نشریه تحقیقات موتور
پیاپی 68 (پاییز 1401)

In this experimental study, the fuel system of the OM364 diesel engine manufactured by IDEM company, which operates in the basic mode with inline fuel pump and mechanical governor control, is upgraded to a common rail system with electronic control by the ECU. Also, emmssion of exhaust gases is reduced by SCR and DOC catalysts then performance and emmission parameters of engine are compared in two cases. The base engine of OM 364 with Euro 2 emission standard is upgraded to Euro 5 EEV emission standard after changing the fuel system to common rail and after refining the exhaust gases with SCR and DOC catalysts. The important point is to pass the Euro 5 EEV standard without using DPF in exhaust gas refining, which reduces the cost of car manufacturers.

Heavy duty vehicles have a great share on fossil fuel consumption and greenhouse gases in the world, while they waste two third of chemical energy of fuel. On the other hand, simplicity and long life of thermoelectric generators (TEGs) are considered more and more to convert thermal energy to electrical one. In this paper a TEG designed in the exhaust system of Renault Midlum 195 Dxi Engine. The temperature and mass flowrate of exhaust gas was measured in a real road test. The height and location of vehicle was recorded by GPS system. The TEG based on two high temperature scoteruidit and low temperature bismuth modules was designed. After designing in SOLIDWORKS, simulation was done using FLUENT. Based on the simulation outputs the power and efficiency of TEG was calculated through thermoelectric fundamental equations. The output power is 1511W, 375W and 466W, in uphill, flat and downhill road respectively.

The controller of the hybrid electric vehicle determines the combustion engine start-stop time, the operation points, and regenerative brake energy. The Controlling approach of hybrid electric vehicles controls the amount of needed fuel in every driving situation. In the present study, the thermostat strategy is implemented along with fuzzy logic control and compared to the classic thermostat strategy. The fuel consumption is compared in two different strategies. GT-power and Simulink software are implemented to simulate the series hybrid electric model. The numerical model is compared and validated with experimental data. The validated numerical model calculates the vehicle fuel consumption in the new European driving cycle. Results show that the use of fuzzy logic control reduces the fuel consumption of series hybrid electric vehicle 4 percent compared to the classical control strategy.

Pressure fluctuations during fuel injection are one of the factors that negative effect on performance of diesel engine. These fluctuations are caused by the rapid opening and closing of the nozzles and the creation of pressure waves in the fuel rail. One way to control these pressure fluctuations is to change the injector design and use an accumulator in the injector. This study is performed to investigate the effect of adding accumulator on the injector to control pressure waves in the common rail fuel injection system of diesel engines. As the simulation results show, at injection pressure of 1000 bar and energizing time of 0.8 milliseconds, in the case of no accumulator, the maximum pressure fluctuation in the fuel rail is 1046 bar and the minimum pressure is 891 bar. By adding an accumulator with a volume of 4 cm3, the maximum pressure continued to decrease and reached 1023 bar, and the minimum pressure of the fuel rail increased by 17 bar, 943 bar. These changes are also noticeable in other pressures and energizing times, so the best accumulator that has the most impact on reducing pressure fluctuations is the accumulator with a volume of 4 cm3.

Todays, the requirement of lowering the vehicle weight for the reduction of the fuel consumption and emissions, one of the methods considered by designers is to use the ligh magnesium alloy under cylclic loadings. In this article, considering the microstructure of the AZ91D magnesium alloy, its crystalline structure, a model for predicting the ratcheting behavior of this alloy was adapted and verified based on experimental data. The crystallographic texture of this alloy will be introduced into the model respecting the manufacturing process of the shaping conditions. The proposed model, in order to simulate the ratcheting deformation, had an acceptable accuracy. However, the values of the ratcheting strain were over-predicted. Moreover, the crystal plasticity model could simulate the first and second stages of ratcheting, hardening effects, mean stress, and stress amplitude, with a higher accuracy.

In performing vibration analysis of the car engine on the engine support, it is necessary to know the mass properties of the engine including mass, position of the center of mass and mass inertia moments. Because the car engine has a relatively complex geometric shape and is composed of different components with different densities, determining its mass properties faces many challenges. There are various methods to determine the mass properties of a car engine, one of the most common of which is the use of modal analysis (mass line method). In this paper, the mass line method is presented in order to find the mass properties of rigid bodies. In order to evaluate the efficiency and accuracy of the method, dynamic modeling of a rigid body with known mass properties is performed in MSC Adams software. So according to the theory of mass line, the rigid body is hung from a soft suspension and a force is applied to it in different locations. Then, by performing Adams simulations, the corresponding acceleration values ​​are extracted at various points. After that, the mass line method is coded in MATLAB software and the applied forces and accelerations obtained from Adams in the time domain are entered as input to the MATLAB code and by executing the MATLAB code, the mass properties of the rigid body are calculated. Finally, the values ​​of the mass characteristics obtained from the MATLAB code are compared with the actual values ​​of the rigid body simulated in Adams, and the accuracy of the mass line method in finding the mass properties is evaluated.