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Noise pollution is a major concern for global automotive industries which propels engineers to evolve new methods to meet passenger comfort and regulatory requirements. The main purpose of an exhaust system in an automotive vehicle is to allow the passage of non-hazardous gases to the atmosphere and reduce the noise generated due to the engine pulsations. The objective of this paper is to propose a Design for Six Sigma (DFSS) approach followed to optimize the muffler for better acoustic performance without compromising on back pressure. Conventionally, muffler design has been an iterative process. It involves repetitive testing to arrive at an optimum design. Muffler has to be designed for better acoustics performance and reduced back pressure which complicates the design process even more.

Noise Pollution has become one of the major environmental concerns for global automotive industry in the current era. Air Induction System (AIS) plays an important role in engine performance and vehicle noise. An ideal design of AIS provides debris free air for combustion and also reduces the engine noise heard at snorkel. Acoustic engineers always face challenges for achieving optimized AIS design with packaging space constraints. Conventionally, AIS optimization is an iterative procedure. This paper emphasizes a one dimensional (1D) approach for optimization of AIS to meet the functional requirements for flow and acoustics. Air flows from the snorkel to the intake manifold whereas the sound propagates in the opposite direction. Suitable design of ducts, air box and resonators are required to attenuate the snorkel noise (SN) to meet the required sound pressure levels.

Noise pollution is a prominent environmental hazard faced by the automobile industry. The design of automotive Air Induction Systems (AIS) plays a crucial part in attenuating noise emitted by an engine. In addition to this, sound attenuating devices are connected in series and in parallel to the AIS for effective noise attenuation. This paper presents three-dimensional (3D) acoustic and flow results of one such sound attenuating device, the Helical Resonator (HR), which is attached to the AIS of a 3.6 L engine replacing the existing Helmholtz resonators (HHR). The baseline AIS has four HHRs to attenuate four major engine noise frequencies. In this paper, design parameters were selected to allow the HR to capture at least two of the four frequencies and minimize the cost at space concerns. The analytical four-pole Transfer Matrix Method (TMM) approach is applied to initially calculate Transmission Loss (TL) and arrive at a suitable set of HR design parameters.

The performance of any automotive engine depends not only upon its core engine parts but also on the effectiveness of the sub-systems attached to the engine, like the intake, fuel, engine cooling and exhaust systems. The exhaust system being a critical system of any automotive vehicle plays a responsible role of improving the ride quality of the vehicle and fuel economy. The effective design of exhaust system is critical in order to ensure the required exhaust gas is exited from the engine and at the same time the noise is attenuated. In this paper a novel approach is developed in order to characterize the flow through the cold end exhaust system and reduce the pressure drop to achieve desired performance. The exhaust system attenuates the noise from the engine without deteriorating the engine performance by ensuring an optimum value of exhaust back pressure.