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Nowadays, by the introduction of significant advances in automotive industries, noise, vibration and harshness (NVH), in the position of the main comfort attribute, plays a crucial role in marketing and passenger satisfaction. In order to cope NVH problems, three main actions are taken by NVH engineers for reducing perceived level of noise in cabin: Noise reduction in sources, Noise path treatment and Noise control at receiver. Among these approaches, those pertain to modification of noise pass, through structure and air, to the cabin are more prevalent in automotive applications. Accordingly, identification of noise paths that dominantly contribute to sound and vibration transfer to cabin phenomenon should be dealt with importance. In practice, engine vibration transmitted through sub-frame attachments to body can induce high level of noise and vibration to the passenger cabin.

Improvements of aerodynamics and wind noise are two important objectives for automotive engineers. Improvement of aerodynamics behavior and the reduction of wind noise have been always greatly concerned by automotive engineers since they negatively affect passengers comfort, fuel consumption, car performance and, stability. In this paper, optimum levels of four dominant rear shape parameters for a simplified car model are investigated considering drag coefficient and aerodynamic noise objectives. C-Pillar angle, trunk angle, boat tail angle and rear box length are considered as variable parameters. Taguchi method is used for finding aerodynamic and acoustic optimum levels. Numerical simulation for base case is compared with experimental results in the literature. Numerical results show good agreement with experimental test. Afterwards, optimum levels for parameters regarding objectives are calculated using Taguchi method.

The efficiency of the vehicle cooling system strongly depends on the air flow through the radiator core. The flow through the radiator core in turn depends on other panels that are in the vicinity of the radiator. In this study, the effect of geometrical change at vehicle front-end including the whole bonnet, grille and bumper area is investigated by means of Computational Fluid Dynamics (CFD). Numerical modeling is carried out by means of CAE tools. Simulations are performed for maximum power and maximum torque conditions, monitoring the mass flow rate through the radiator core and velocity contribution over the radiator face. To the velocity field of the airflow, the heat exchangers are represented as porous media and fan module is modeled utilizing Multiple Reference Frame (MRF) approach. The validity of the developed simulation capability is tested by successful comparison with the available experimental data for the base model at the given operating conditions.

The main objective of this study is to investigate the effect of spot-weld modeling approaches on NVH virtual simulation problems. For this purpose, finite element method is considered for further simulations. The goal is to evaluate and compare results within the domain of 0 to 200 Hz by modeling spot-welds with three different element types: a rigid body constraint element (RBE), two rigid body elements with hexahedral solid element (RBE3-HEXA-RBE3) and CWELD constraint. In order to evaluate the effects, three main NVH analyses are chosen for this study. In the first place, a free-free modal analysis is performed for the BIW and trimmed body models of a D-segment saloon car in order to estimate natural frequencies and mode shapes. Afterwards, a frequency response analysis is performed to evaluate the dynamic stiffness of engine mount. Finally, a noise transfer function (NTF) simulation is carried out to calculate the sound pressure level at driver ear's location.

Efficient function of brake system is considered a crucial stage in the vehicle development process. Heat exchange reduction can decrease the operational condition of braking system. Although the rims patterns have a significant role on vehicle aerodynamics, they can also have effect on air flow around the brake disk. So, selecting a rim is vital from both a safety and an aerodynamic point of view. In this paper the effect of air flow around a brake disk for two different types of rims was studied; a steel casting and an aluminum alloy rim. Numerical simulation was used for this analysis. First, the flow field around brake disk with iron casting rim was investigated at different velocities. Second, the flow field around the same brake disk system with an aluminum alloy rim was modeled at the same velocities. Finally, the effect of rim design on flow pattern over brake disk was compared.

Adequate visibility through the automobile windscreen is a critical aspect of driving, most often at very low temperatures when ice tends to be formed on the windscreen. The geometry of the existing defroster system needs to be improved in the vehicles, with the main aim of substantial increase in air mass flow reaching the windscreen through defroster nozzles and appropriate velocity distribution over the windscreen, while respecting all packaging constraints. The reason of this study is to investigate the windscreen deicing behavior of a vehicle by means of Computational Fluid Dynamics (CFD) with the main concern of improving deicing process by design an appropriate defroster. Two different defrosters with completely different geometry are considered for this purpose. A detailed full interior model of an existing vehicle is created via CAE tools.

The main purpose of this research is to reduce the transmitted engine vibration to the subframe structure via improving the mobility of engine mountings. In fact, the main focus is on the geometry optimization of the subframe part, implementing the design of experiments method, to increase the dynamic stiffness of the part to reduce the vibration transfer function in the mountings location. In order to perform the optimization process, the front end model of the reference vehicle including the suspension, steering system, engine and deriveline system is generated in FE software. According to the prevalent guidelines, the mobility of engine mountings should be greater than target value which is usually obtained through benchmarking. To do so, some structural parameters that are apt to influence on the mobility function, e.g the section of subframe, thickness of subframe and vehicle body are selected as design variables for doing the design of experiments analysis.

Nowadays, outer surface design of passenger cars is not just a matter of styling and safety but air flow around car body and exterior accessories has significant effect on fuel consumption, performance and dominantly on the wind noise. In recent years, passenger comfort is one of the most challenging and important automotive attributes for car makers. Controlling the turbulence eddies that causes aerodynamic noise can remarkably affect passenger's comfort quality. Identification of aerodynamic sources is considered as the first step in order to control the wind noise. In this research, computational fluid dynamics method is applied to simulate the wind flow around the car and the investigation of aerodynamic noise pattern is performed by numerical method which is the most prevalent way that is used by auto industries.