Automotive Science and Engineering

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Turning of hardened steels using a single point cutting tool has replaced the cylindrical grinding now as it offers attractive benefits in terms of lower equipment costs, shorter set up time, fewer process setups, higher material removal rate, better surface quality and elimination of cutting fluids compared to cylindrical grinding. In order to obtain desired surface quality by machining, proper machining parameters selection is essential. This can be achieved by improving quality and productivity in metal cutting industries. The present study is to investigate the effect of machining parameters such as cutting speed, feed and depth of cut on surface roughness during dry turning of hardened AISI 4340 steel with CVD (TiN+TiCN+Al2O3+ZrCN) multilayer coated carbide inserts. A full factorial design of experiment is selected for experimental planning and the analysis of variance (ANOVA) has been employed to analyze the significant machining parameters on surface roughness during turning. The results showed that feed (60.85%) is the most influencing parameter followed by cutting speed (24.6%) at 95% confidence level. And the two-level interactions of feed-cutting speed (F*V), depth of cut-feed (D*F) and depth of cutcutting speed (D*V) are found the significant effects on surface roughness in this turning process. Moreover, the relationship between the machining parameters and performance measure i.e. surface roughness has been modeled using multiple regression analysis.

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The current experimental study is to investigate the effects of process parameters (cutting speed, feed rate and depth of cut) on performance characteristics (surface roughness, machining force and flank wear) in hard turning of AISI 4340 steel with multilayer CVD (TiN/TiCN/Al2O3) coated carbide insert. Combined effects of cutting parameter (v, f, d) on performance outputs (Ra, Fm and VB) are explored employing the analysis of variance (ANOVA). An L9 Taguchi standard design of experiments procedure was used to develop the regression models for machining responses, within the range of parameters selected. Results show that, feed rate has statistical significance on surface roughness and the machining force is influenced principally by the feed rate and depth of cut whereas , cutting speed is the most significant factor for flank wear followed by cutting speed. The desirability function approach has been used for multi-response optimization. Based on the surface roughness, machining force and flank wear, optimized machining conditions were observed in the region 147 m/min cutting speed and 0.10 mm/rev feed rate and 0.6 mm depth of cut.

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Induction motors are the most commonly used in the traction industries and electric vehicles, due to their low primary cost, low maintenance costs, and good performance. Speed identification is needed for the induction motor drives. However, using of speed sensors in the induction motor drives is associated with problems such as, extra cost, reduced reliability, added mounting space, etc.. Therefore, many of the recent researches had been dedicated to sensor less induction motor drives. In the induction motor, the rotor speed is estimated using measured stator voltages and currents of the induction motor, as the sensor less drive. The rotor speed for sensor less induction motor drives can be estimated by various techniques, which is designed with respect to required accuracy and sensitivity against induction motor parameter variation. In this paper, comprehensive review of different induction motor speed estimation techniques for traction applications, their special features and advantages is presented.

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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.

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In this paper an idea for hybridization of conventional vehicles has proposed. The case study performed on one of the common vehicles on country roads i.e. Samand. This vehicle has high production volume but low fuel performance therefore hybridization of it could be attractive for its manufacture. This paper aims that the hybridization idea and its structure to need minimum mechanical modifications. In consequence attractiveness of this idea for industry could be high. A cost optimization has been performed for sizing of additional components such as electric motors and battery modules and the simulation results has been adopted to verify the proposed idea for case study with hybrid simulation of GT-Suit and MATLAB softwares.      

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Thin-walled columns are frequently employed in vehicle structures to diminish the damages resulting from vehicle collisions. In this research, the effect of hole shapes and dimensions on crushing behavior of octagonal multi-cell columns subjected to longitudinal loading is studied. Rectangular, hexagonal and elliptical holes are assumed on the octagonal multi-cell columns, and crushing parameters (i.e. specific energy absorption SEA and maximum crushing force F_max) are then obtained by performing numerical analyses in LS-DYNA. The results demonstrate that creation of holes on column walls improve crushing capability significantly, such that creation of rectangular, hexagonal and elliptical holes on the octagonal multi-cell columns increases the value of SEA by 37%, 42% and 39%, respectively in comparison to the plain octagonal column. On the other hand, presence of holes on the octagonal columns results in reduction of F_max (as a negative crushing indicator).

 

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As alternatives for future refrigeration, heat pumping, air conditioning, or even power generation plants are emerging due to the regulatory changes, R744 (carbon dioxide) is considered as a serious alternative to be the successor of other Halogenated Hydrocarbons Refrigerants (HHR) for the AC-system of vehicles. This paper investigates the heat transfer performance of R744 through a subcritical vehicular condenser, designed and manufactured for the first product based on NP01 platform (Iranian vehicle), at different operating conditions in terms of refrigerant mass flow rate and wind velocity. The experiments carried out in order to investigate the effect of mass flow rate, the R744 inlet temperature was observed to have sudden fluctuations. At the condenser outlet, for the smallest mass flow rate, the least variation of temperature was observed. It was also found out that for higher air velocities through the condenser, the stabilized temperature after the condenser was lower. The results show that the performance of the designed and manufactured automotive condenser based on R744 refrigerant is acceptable which makes it a suitable candidate for automotive applications.
As alternatives for future refrigeration, heat pumping, air conditioning, or even power generation plants are emerging due to the regulatory changes, R744 (carbon dioxide) is considered as a serious alternative to be the successor of other Halogenated Hydrocarbons Refrigerants (HHR) for the AC-system of vehicles. This paper investigates the heat transfer performance of R744 through a subcritical vehicular condenser, designed and manufactured for the first product based on NP01 platform (Iranian vehicle), at different operating conditions in terms of refrigerant mass flow rate and wind velocity. The experiments carried out in order to investigate the effect of mass flow rate, the R744 inlet temperature was observed to have sudden fluctuations. At the condenser outlet, for the smallest mass flow rate, the least variation of temperature was observed. It was also found out that for higher air velocities through the condenser, the stabilized temperature after the condenser was lower. The results show that the performance of the designed and manufactured automotive condenser based on R744 refrigerant is acceptable which makes it a suitable candidate for automotive applications.
 

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This paper presents an experimental study on the effect of adhesive thickness on the maximum load of adhesive joints under static and impact loading, using the double cantilever beam (DCB) test method. The DCB specimens were prepared with varying adhesive thicknesses and subjected to impact loading using a drop weight impact tester. The maximum load was recorded for each specimen. The results indicated that the maximum load of the adhesive joints increases with increasing adhesive thickness up to 5 mm, beyond which the maximum load decreases with further increase in adhesive thickness. Moreover, the failure mode of the adhesive joint was found to be strongly dependent on the adhesive thickness, with thicker adhesive layers exhibiting an adhesive failure mode but in thinner thicknesses, the adhesive mode is cohesive. These findings provide important insights into the design and optimization of adhesive joints for applications that are subject to impact loading.