Wind noise is one of the most influential NVH attributes that impact customer sensation of vehicle interior quietness. Among many factors that influence wind noise performance, the amount of dynamic d....
Recent developments in the prediction of the contribution of wind noise to the interior SPL have opened a realm of new possibilities. The main physical mechanisms related to noise generation within a ....
The authors report on the design and application of a high resolution micro-electro-mechanical (MEMS) microphone array for automotive wind noise engineering. The array integrates both sensors and rand....
When a sunroof opens to let in fresh air while driving, there might be several noise issues associated with it. The most common and painful one is the wind throb issue, which is nevertheless largely r....
For the automotive industry, acoustic comfort is of increasing importance. The market and customer expectation make the HVAC system noise quality a question to be addressed as early as possible in the....
At high cruising speed, the car A-pillars generate turbulent air flow around the vehicle. The resulting aerodynamic pressure applied on the windows significantly contributes to the total cabin noise. ....
For the automotive industry, the quality and level of the wind noise contribution has a growing importance and therefore should be addressed as early as possible in the development process. Each compo....
Indoor vehicle pass-by noise applications deal with measuring the exterior noise from a vehicle fixed on a chassis dynamometer in a large hemi-anechoic room. During a standardised acceleration test, t....
A new pass-by noise test method has been introduced, in which engine speeds and loads are reduced (compared to the old test method) to better reflect real world driving behavior. New noise limits appl....
The hanger location layout is crucial, because it is related to the rubber hanger life, the natural frequency of the exhaust system and the force transferred to the body from the exhaust system. In or....
A simulative program named as MAP (Muffler Analysis Program) is developed for the rapid calculation and analysis of acoustic characteristics of duct muffling systems. The program is based on the plane....
In several applications, two-inlet single-outlet mufflers are possible to encounter in exhaust systems. They are usually used to merge two exhaust streams from two similar engines or from two sides of....
The acoustic performance of mufflers with single-inlet and single-outlet are well described using Insertion Loss (IL) and Transmission Loss (TL). These parameters represent the acoustic damping on the....
Exhaust and muffler noise is a challenging problem in the transport industry. While the main purpose of the system is to reduce the intensity of the acoustic pulses originating from the engine exhaust....
Flow strongly affects the propagation of acoustics wave transmission within a duct and this must be addressed by the vibro-acoustic modelling of duct systems subject to non-uniform flow. Flow impacts ....
A simplified method to model perforated tubes in mufflers is the equivalent transfer impedance approach. Various empirical formulas that consider the porosity, hole diameter, wall thickness, and flow ....
Development of split Catalytic Converter (Cat-Con)-Muffler system was done to be used in front engine low floor (FELF) Bus from perspective of cost saving, modularity and reduction in complexity. This....
The Sound Transmission Loss of automotive intake and exhaust components is commonly measured using the four microphone tube method per ASTM E2611 [1]. Often area adapters are used to match the compone....
The bias flow in Concentric Tube Resonator (CTR) is a flow-induced phenomenon in which the pressure gradient along the radial direction is produced by the kinetic energy of the flow. As a result, the ....
The two-load method is commonly applied to determine the transmission loss for a muffler especially if an impedance tube rig is used. Although one procedure and algorithm is detailed in ASTM E2611, th....
