Automotive Science and Engineering
Volume:9 Issue: 4, Autumn 2019

Thin-walled structures play an important role in absorbing the energy in a low impact crash of vehicles up to saving lives from high impact Injury. In this paper, the thin-walled columns by using a hybrid Design of Experiments (DOE) and Ant Colony Algorithm (ACO) has been optimized. The analysis of the behavior of the nonlinear models under bending load is done using finite-element software Abaqus. The objective is to study the performance geometrically parameters of the columns using DOE-ACO approach. DOE method is being applied to determine the effects of cross-sections, material, and thickness on the energy absorption; and the ACO method is used for finding more accurate thickness on energy absorption. Four types of thin-walled cross-sections, i.e., circle, ellipse, hexagon, and square are used in this study. The optimized results of DOE method show that aluminum alloy (Al-6061) and high strength low alloy steel (HSLA) square columns have a higher energy absorption in comparison with the other cross-sections. However, the amount of absorbed energy in two types of columns is equal but, 50 percent weight reduction may be seen in Al-6061 columns. The columns are re-optimized by ACO to find the best thickness in the last step. In the following, by topology optimization participation, a new plan is proposed by the same thickness and 50% less weight, that has a higher crashworthiness efficiency by increasing SAE more than 70%. As a result of this plan is bridging the gap between standard topological design and multi-criteria optimization.

Nowadays, with increasing environmental pollution and damages that threaten the health of the community, a lot of research is being conducted on reducing the emission from transportation sector as one of the main sources of total worldwide emissions. It is confirmed that one of the ways to reduce emission is to switch from fossil-based fuels to more environmentally benign fuels. Among the options, electric vehicles (EVs) have proven themselves as one of the best options. In this research study, a solar-based EV which is developed and built at University of Tehran is studied.  The environmental impacts assessment along with the energy consumption of this solar-electric vehicle is investigated

According to the global air pollution Crisis, it seems necessary to finding a way for cars pollutions. The Combination of alcoholic fuels with gasoline is one of the methods to reduce pollutions. For optimizing engine performance, fuel availability, toxicity and political advantage, a blend of ethanol, methanol and gasoline is likely to be preferable to using any of these individual substances alone. So the purpose of this paper is studying methanol, ethanol and gasoline blend effect on engine emissions at different engine speed. The simulated model was validated in different RPMs of gasoline engine at full load condition. The effect of combined fuel injection in the simulated model was investigated and compared with the experimental results. The results of simulation have good agreement with experiments. The results show that by ethanol and methanol with gasoline blend CO and HC emissions are lower than gasoline mode, but the NOx and CO2 pollutants increases.

Heavy articulated vehicles have low performance with respect to stability analysis due to their multifaceted geometry and dynamics especially when it comes to non-linear maneuvers. In this study in order to find out which statistical and dynamical factors have the most effect on stability of this type of vehicle without getting involve with their complex mathematical theory, combination of drive simulation and Taguchi method is used. Since the number and variety of factors are extensive, multi-step Taguchi method used. This method applied on values of modified rearward amplifications of each units of vehicle as a criterion of  lateral stability. Results show the high effect of suspension and load geometry of Vehicle Units on lateral stability and safety.

One of the most significant issues of recent decades is pollution and dangers that may threat the environment. Different approaches were presented to protect the environment and target various sources of pollution. Old vehicles are one of the major sources of pollution in megacities as they consume and emit a lot of emissions. Therefore governments in different countries try to levy tax on pollution to motivate people to drive environment friendly and more efficient vehicles. Tehran is one of the cities suffering rigorously from poor air quality. As a result, approximately 44 days in each year the air quality reckons as unhealthy for all residents. One of the suggested solutions is replacing conventional taxis across the city with hybrid electric vehicles. In this article this solution for the city of Tehran, Iran will be discussed and its feasibility will be evaluated using life cycle assessment.   In order to conduct this, first data associated with air quality, pollution and taxis distribution in the city were presented. Then different designated vehicles were evaluated based on their technical performance and the emission they generate in different stages. Using the proposed model a comprehensive cost is defined and different vehicles were compared and the most viable choices by various considerations is introduced.

Changing various parts of different types of engines in the maintenance phase was always a remarkable question. Purpose of the present study is identifying the performance and emissions of a diesel-fueled engine (OM457) before and after replacing connecting rod and crankshaft with another engine (OM444) in the same engine family. At the first step, a solid model was made then some CFD analyses were done and, results were compared with previous studies for validation after that in the CFD modeling the impact of these parts replacement were observed, and the performance and emissions of this engine were compared with data before replacements. As the result of these replacements, compression ratio and performance were decreased. HC and CO were increased due to lower air-fuel ratio, and NOX was decreased because of the lower temperature of in cylinder. Lowering the CR of a diesel engine will reduce the NOx emission numerously but the increase in other emissions will be slight. So for the environment issues lowering the CR will be a practical and low cost method.