Automotive Science and Engineering
Volume:6 Issue: 2, Spring 2016

In this paper, a two-surfaces sliding mode controller (TSSMC) is proposed for the voltage tracking control of a two input DC-DC converter in application of electric vehicles (EVs). The imperialist competitive algorithm (ICA) is used for tuning TSSMC parameters. The proposed controller significantly improves the transient response and disturbance rejection of the two input converters while preserving the closed-loop stability. The combination of the proposed controller and ICA, realizes a fast transient response over a wide transient load changes and input voltage disturbances. For modeling the equations governing the system, state-space average modeling technique is used. In order to analyzing the results, the two input converter equipped with the proposed controller, was modeled in MATLAB/SIMULINK environment. Simulation results are reported to validate the theoretical predictions and to confirm the superior performance of the proposed nonlinear controller when it is compared with a conventional pure SMC.

In recent years due to improvements of technology within automobile industry, design process of advanced driver assistance systems for collision avoidance and traffic management has been investigated in both academics and industrial levels. Detection of traffic signs is an effective method to reach the mentioned aims. In this paper a new intelligent driver assistance system based on traffic sign detection with Persian context is designed. The main goal of this system is to assist drivers to choose their path based on traffic signs more precisely. To reach this purpose, a new framework by using of fuzzy logic was used for detection of traffic signs in videos which have has been captured from a vehicle path in highways. Fuzzy logic increases inference and intelligent capabilities in smart systems to make correct decision making in online conditions. Then, the combination of Maximally Stable Extermal Regions (MSER) and Canny Edge Detector Algorithms are used to detect road sign’s texts detection. MSER algorithm is aimed at assists to detect regions in an image that differ in properties, for example in brightness or color, compared to surrounding regions. Also, canny edge detector uses a multi-stage algorithm to detect a wide range of edges in the images. Thereafter, morphological mask operator is used to join individual characters for final detection of texts in the traffic signs. Finally, MATLAB Optical Character Recognition (OCR) is employed to recognize the detected texts. This new framework gives an overall text detection and recognition rate of .

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.  

Loading conditions and complex geometry have led the cylinder heads to become the most challenging parts of diesel engines. One of the most important durability problems in diesel engines is due to the cracks valves bridge area. The purpose of this study is a thermo-mechanical analysis of cylinder heads of diesel engines using a two-layer viscoplasticity model. In this article, mechanical properties of A alloy, obtained by tensile tests at and C. Tensile tests were simulated by abaqus software and very good agreement was shown between experimental and simulation results of tensile tests. The results of the thermo-mechanical analysis indicated that the maximum temperature and stress occurred in the valves bridge. The results of the finite element analysis showed that when the engine is running the stress in the region is compressive caused by the thermal loading and combustion pressure. When the engine shut off the compressive stress turned into the tensile stress because of assembly loads. The valves bridge was under the cyclic tensile and compressive stress and then is under low cycle fatigue. After several cycles the fatigue cracks will appear in this region. The results of the thermo-mechanical analysis of cylinder heads correspond with the simulation results, carried out by researchers. Viscous strain was significant and its amount is not negligible.

New product development (NPD) is described in the literature as the transformation of a market opportunity into a product available for sale [ ]. In the automotive industry, within the context of ISO/TS (the automotive quality management system international standard), consists of Three main phases such as planning, Implementation and sales. There are also five sub phases called “Planning”, “Product Design”, “Process Design and Development”, “Product and Process Verification and Validation”, and “Production”. These phases may be done concurrently and have correlated activities. Our analysis shows that most of domestic researches about the new product development success factors are based on the Western literature and use them as the theoretical platform in the design of their own research strategy and research questions design. The paper proposes a contribution of measuring indicators extracted from literature review and completed by several industry and university experts’ interviews to finalizing the weighting indictors that could be useful in performance measuring on Auto new product development gates.

Modern diesel engines should have higher pollutant emissions standards with better performance and by using split injection strategies which could optimize the air – fuel mixture, this purpose could be achieved. After achieving the successful validation between modeling and experimental results for both single and double injection strategies, for the first time and in this paper, double injection strategies with new nozzle configuration were used in which number of nozzle holes were doubled and located below the previous holes and then double injection strategies were implemented in a case that for each pulse of injections upper or below holes were used, then this study focused on the effects of the new nozzle configuration holes angle in each pulse of injections. This study confirms that split injection could decrease Nox emission, because it has lower maximum in-cylinder temperature than single injection case due to its separate second stage of combustion, also results showed that using new nozzle configuration with two rows of holes could be more effective in decreasing pollutant emissions without any significant effects on engine performance.