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In the recent past a lot of emphasis is given for the overall weight reduction of the sound package used in the vehicles. The paper presents a study of one of such materials used in the automotive market. The dash panel is a primary area for the engine noise transmission to the cabin. Hence the material selection of the dash inner acoustic insulation is critical. In the conventional method a barrier (EVA) and a decoupler (foam) is used. In the conventional design the surface weight of the barrier has to be substantially high for the dash insulation to perform effectively and hence adds to more weight. In the present application of light weight material also known as dual density absorbers and barrier is used for the dash acoustic insulator. The study reveals the good acoustic performance of the light weight dash mat in terms of passenger cabin noise reduction and improved sound quality along with weight reduction.

One of the primary excitation sources in a passenger car comes from the powertrain [1]. Refinement of powertrain induced noise is the most critical tasks during a vehicle refinement. Due to ever increasing demand for reduced design and development cycle, most critical decisions have to be made at the concept stage. Powertrain radiated noise is one of the most important performance factor that must be evaluated during the concept stage. Solution time for calculating the radiated noise using the existing acoustic solvers is very high and requires very expensive resources like software and hardware. Arriving the optimal design with conventional method is very tedious job. A new method has been adopted for identifying the critical areas and coming up with the optimal design modifications within a short span of time. Powertrain radiated noise has been calculated with the help of acoustic solver.

Idle NVH (Noise Vibration Harshness) is one of the major quality parameters that customer looks into while buying the vehicle. Idle shake is undesirable vibrations generated from Engine while it is in idling condition. These low frequency vibrations affects both driver and passenger comfort. Vibrations are perceived by customer through the interfaces such as the seats, floor, and steering wheel. The frequencies of vibration felt by customer ranges between 10-30 Hz and varies based on engine configurations. There are two factors that are critical to the vehicle idle NVH quality, 1. Engine excitation force and 2. Vehicle sensitivity to excitation forces (Transfer function). Even though the engine excitation forces are governed by cylinder combustion process inside the cylinder and engine mass, it is also largely affected by how well the engine and transmission are supported on vehicle through isolators.

In vehicle Front End Flow (FEF) analysis, the basic objective is to predict the mass flow/velocity of air at radiator inlet with constant fan rotation. In general, the Multiple Reference Frame (MRF) model is used to model the fan. The flow velocity distribution at radiator inlet due to fan rotation should be uniform in circumferential direction whereas, it should vary in radial direction depending upon the blade geometry. However, the drawback with MRF model is that, it gives higher velocities near radiator inlet at regions corresponding to the fan blades and lower velocities at other regions, which is not realistic. This issue is more predominant when the vehicle is at low speeds or when radiator is placed at mid or back of the vehicle or the fan is having less number of blades. In order to nullify this uneven velocity distribution at radiator inlet, Mixing Plane (MP) approach was used in addition to the MRF model.

Electric cars are the future of urban mobility which have very less carbon foot print. Unlike the conventional cars which uses BIW (Body in White), some of the electric cars are made with a space frame architecture, which is light weight and suitable for low volume production. In this architecture, underbody consists of frames, battery pack, electronics housing and electric motor. Underbody drag increases due to air entrapment around these components. Aerodynamic study for baseline model using CFD simulations showed that there was a considerable air resistance due to underbody components. To reduce the underbody drag, different add-ons are used and their effect on drag is studied. A front spoiler (air dam) is used to deflect the incoming air towards sides of the car. A under hood cover for front components, trailing arm cover for trailing arm and rear bumper cover for rear components were used to reduce underbody drag.