Automotive Science and Engineering

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Air pollution is one of the major issues about the diesel engines in todays' world. It is a special concern in those areas that have difficulty meeting health-based outdoor air quality standards. Natural gas has low emission and resource abundance and also conventional compression ignition engine can be easily converted to a dual fuel mode to use natural gas as main fuel and diesel as pilot injection. The main object of this work is to investigate the effect of number of injector nozzle hole on the combustion and exhaust emission in a gas engine ignited with diesel fuel. We use one and three-dimensional simulation in parallel way in order to analyze the performance and combustion process of a dual fuel engine. The experimental results have also reported and compared with the simulated data.

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The viscoelastic effect of rubber material on creation of rolling resistance is responsible for 10-33% dissipation of supplied power at the tire/road interaction surface. So, evaluating this kind of loss is very essential in any analysis concerned with energy saving. The transient dynamic analysis for including the rolling effects of the tire requires long CPU time and the obtained results are prone to considerable numerical oscillations. By adding the equivalent loads to static interaction of tire with the road, an efficient 3D FE analysis is presented for evaluating the dissipated energy of a rolling tire. The results closely match the related experimental and numerical investigations.

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In this study, a numerical computational fluid dynamics study is conducted in order to predict the aerodynamic forces on the NP car. The turbulent air flow around the car is modeled using the realizable k-ε model. First, results are validated against those presented for the Ahmed’s body. Next, the fluid flow around the car is simulated for different car speeds ( to mph) and flow directions ( to degree) and the drag and lift forces and coefficients are calculated. Increasing the car speed leads to increase of the drag and lift forces. While, the drag and lift coefficients of the car for all studied speeds are almost constant and are respectively equal to . and . . In addition, for different flow directions the drag coefficient would increase up to . . Also, the effect of mirrors on the drag force is investigated. Results reveal that removing the mirrors leads to approximately reduction in the drag force with no significant reduction in the drag coefficient. Furthermore, the effect of car elevation on the drag and lift forces is analyzed. It has been shown that when the car elevation decreases up to mm, the drag force will decrease more than , and the drag and lift coefficients are still constant. Keywords: road sign detection, text detection, object detection from video, fuzzy logic, MSER

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This paper investigates 3D simulation of fluid flow in a centrifugal pump from the Detroit Diesel company to extract possible engine cooling trends.  The velocity and pressure profile of water, the coolant, is analyzed and the characteristic curves of the pump are derived. This provides a useful evaluation of the pump performance at all working conditions. For this aim, a computational fluid dynamic model is developed using ANSYS CFX for a wide span of flow rates and a number of shaft angular velocities. The variation of constituting parameters are examined using dimension-less descriptive parameters of flow, head and power coefficients, finally, the efficiency of the pump is examined. In this analysis, sst-k-w turbulent model is employed which is a combination of two different models for pumps and turbomachines. Numerical results show that prolonged cooling duty cycles of the vehicle should accompany a flow factor of 10%. In addition, the peak of the vehicle’s loading should match the maximum efficiency of the pump that can be increased to 62% by augmentation of flow rate and flow coefficient.