Automotive Science and Engineering
Volume:7 Issue: 4, Autumn 2017

Car design incorporates many engineering sciences where today, have led to the use of advanced technologies in automobiles to provide more satisfaction and comfort for the passengers, increase the quality of vehicles, efficiency and more pleasure than previous cars. These issues can be categorized into two groups in general. In the first group, the effects and performance of components involved in vehicle vibrations are considered, and in the second group, attention is paid to the importance of joints and junctions of these components. Heretofore, in order to minimize vehicle NVH (noise, vibration and harshness), an exuberance of efforts have been done to raise the passengers comfort. In the meantime, it should be noted that the engine mounts play a considerable and serious role in reducing vibration exchanged between the engine and chassis. In designing the engine mounts, the most important concern is to balance the two opposite criteria that come into the car as a result of different vibration inputs (road and motor). Generally, vehicle engine mounts are used by three types of targets (motor bearing weight, motor vibration absorption, motor overloading, acceleration or braking). With the development of the automotive industry, the tendency towards the use of more efficient engine mount categories, has been prepared. This article describes a concise functional overview of the engine mount in automobiles; it illustrates operating frequency range, relationship of the P and boundary diagram of engine mounts with other car collections, torque roll axis, positioning public types of the car’s engine mounts; and it also compares their operations. Afterwards, the structure and the basic functional of hydraulic engine mount are described as the most common engine mount categories. Finally, advantages and disadvantages of various types engine mounts with capability of use in the vehicle (including elastomeric, hydraulic (with inertia track or/and decouplier or/and bell plate (plunger), semi-active (switchable) and active hydraulic engine mount) are compared with each other.

In this paper a new type of multi-objective differential evolution employing dynamically tunable mutation factor is used to optimally design non-linear vehicle model. In this way, non-dominated sorting algorithm with crowding distance criterion are combined to fuziified mutation differential evolution to construct multi-objective algorithm to solve the problem. In order to achieve fuzzified mutation factor, two inputs as generation number and population diversity and one output as the mutation factor are used in the fuzzy inference system. The objective functions optimized simultaneously are namely, vertical acceleration of sprung mass, relative displacement between sprung mass and unsprung mass and control force. Optimization processes have been done in two bi- and three objective areas. Comparison of the obtained results with those in the literature has shown the superiority of the proposed method of this work. Further, it has been shown that the results of 3-objective optimization include those of bi-objective one, and therefore it gives more optimum options to the designer

Proton exchange membrane (PEM) fuel cells being employed in fuel cell vehicles (FCVs) are promising power generators producing electric power from fuel stream via porous electrodes. Structure of carbon paper gas diffusion layers (GDLs) applying in the porous electrodes can have a great influence on the PEM fuel cell performance and distribution of temperature, especially at the cathode side where the electrochemical reaction is more sluggish. To discover the role of carbon paper GDL structure, different cathode electrodes with dissimilar anisotropy parameter are simulated via lattice Boltzmann method (LBM). The distributions of temperature through the GDL as well as the distribution of temperature on the catalyst layer are presented and analyzed. The results indicate that when the carbon fibres are more likely oriented normal to the catalyst layer the distribution of temperature becomes more uniform. Besides, the maximum temperature occurs in this case.

The Global Positioning System (GPS) and an Inertial Navigation System (INS) are two basic navigation systems. Due to their complementary characters in many aspects, a GPS/INS integrated navigation system has been a hot research topic in the recent decade. The Micro Electrical Mechanical Sensors (MEMS) successfully solved the problems of price, size and weight with the traditional INS. Therefore they are commonly applied in GPS/INS integrated systems. The biggest problem of MEMS is the large sensor errors, which rapidly degrade the navigation performance in an exponential speed. Three levels of GPS/IMU integration structures, i.e. loose, tight and ultra tight GPS/IMU navigation, are proposed by researchers. The loose integration principles are given with detailed equations as well as the basic INS navigation principles. The Extended Kalman Filter (EKF) is introduced as the basic data fusion algorithm, which is also the core of the whole navigation system to be presented. The kinematic constraints of land vehicle navigation, i.e. velocity constraint and height constraint, are presented. A detailed implementation process of the GPS/IMU integration system is given. Based on the system model, we show the propagation of position standard errors with the tight integration structure under different scenarios. A real test with loose integration structure is carried out, and the EKF performances as well as the physical constraints are analyzed in detail.

Brake system performance significantly affects safety, handling and vehicle dynamics. Therefore, the objective of this paper is to discuss brake system characteristics and performance and component design parameters. We perform a detailed study of a specific brake system designed for Mercedes-AMG SLC-43, considering component design parameters and operational points, and finally conduct the vehicle braking system layout design. To this end, brake force and torque calculations and power dissipation modelling is performed. Then, ventilated brake discs are designed for the front and rear brakes. A main goal of the present article is to apply digital logic method to the material selection procedure among the candidate material proposed for brake components and rank the materials according to performance indices. The performance indices of five candidate materials were calculated and compared to select the best option for application in the brake disc. Finally, the calculations of the brake pedal, booster, cylinder, hoses and tubes are obtained.

Fillers can be employed as reinforcement in the design of automobile crash boxes to improve its performance in terms of energy absorption, expected crushing fashion and initial peak force magnitude. The current research focuses on the investigation of crashworthiness of the high-strength steel (HSS) columns filled with reinforced aluminium honeycomb fillers. The crashworthiness of HSS steel crash boxes embedded with aluminium honeycomb of varying thickness and  cell sizes are investigated. Five variants of honeycomb thickness, namely; Thickness-1, Thickness-2, Thickness-3,Thickness-4, Thickness-5 and six variants of honeycomb cell size, namely; CellSize-1, CellSize-2, CellSize-3, CellSize4, CellSize-5 and CellSize-6 are considered for the crash box analysis. Numerical crash analysis is performed for the novel reinforced sandwich honeycomb separated by steel plates in HSS crash box. A further study is also performed by inducing V-Notch triggers in the honeycomb to evaluate the effect of crashworthiness parameters. A comparative numerical investigation is performed to realize the effect of geometric parameters on the crashworthiness variables of crash boxes for low-velocity impact. The force versus displacement curves were derived and analyzed for each parameter variations and detailed comprehension of deformation pattern and energy absorption are provided. The objectives of the present work is to showcase the effect of honeycomb geometric parameters like thickness and cell size on crashworthiness parameters for low-velocity impact and also to represent the effect of sandwich honeycomb and honeycomb with V-Notch triggers methodology on the crashworthiness parameters like initial peak force (IPF), energy absorption (EA), specific energy absorption (SEA) and crush force efficiency (CFE)