• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.1654-1660
• /
• 2000

Recently, the regulations from the government and the concerns of people give rise to the interest in exhaust and intake noise of passenger car as much as other vehicles. In these demands, performance prediction software was developed in the previous study. In this study, Robust design was used for improving the noise reduction capacity of intake system with the performance prediction software. On the basis of the existing design, length and radius of each component that was thought to effect to capacity of intake system was selected. At first factors are arranged by using $L_{18}$ table of orthogonal array and then optimum value can be obtained by $L_{16}$ table of orthogonal array.

• Proceedings of the Acoustical Society of Korea Conference
• /
• autumn
• /
• pp.375-378
• /
• 2001

천공 요소는 유체 기계의 흡기계나 배기계의 소음기에 널리 사용되고 있으며, 스치는 유동 (grazing flow)과 통과하는 유동 (cross flow)을 접하게 된다. 천공 요소의 임피던스는 소음기의 음향학적인 특성에 영향을 미치게 된다 본 연구에서는 유동이 임피던스에 미치는 영향을 고려하기 위하여, 실험을 통하여 얻은 임피던스 값을 유동 레지스턴스 (flow resistance)와 종단 보정 비 (end correction ratio)로 나타내고, 스트롤 수 (Strouhal number)로 무차원 화하여 분석하였다 이를 난류를 고려하여 제안된 선행 임피던스 모델들과 비교하여 난류가 미치는 영향을 분석하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2011.10a
• /
• pp.833-838
• /
• 2011

Future powertrain technologies will be developed focused on applications of eco-friendly technology for internal combustion engine, electric vehicle and Fuel Cell Electric Vehicle. But it is expected that these cutting edge technologies will not be applied immediately due to lack of infrastructure, technical and economical reasons. Therefore, numerous developments of internal combustion engine will be carried out for the time being. There have been many turbo engine developments undergoing to maximize the engine performance using turbo charger system in accordance with global trend-green technology and downsizing of engine which coincides with HMC's future development strategy. This study reviews the development process and result of plastic intake manifold module which is firstly developed for turbo engine. CAE simulation and experiments were implanted to evaluate design validity.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.05a
• /
• pp.114-119
• /
• 2003

In this paper, the experimental design of an intake system was studied using the two microphones method and the taguchi method. The transmission loss was utilized to represent the performance of noise reduction for the intake system which was estimated by measuring sound power at inlet and outlet with two microphones, respectively. Two microphones method used in this paper was followed by wave decomposition theory The robust designing parameters of an intake system were extracted by adapting a cost function with the taguchi method, which optimized the process. Finally the effectiveness of the propose method was validated with the experimental data.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.11a
• /
• pp.182-186
• /
• 2000

The porous woven hose is recently considered as an effective element of automotive intake systems. In order to predict the acoustic performance of an intake system with a porous woven hose, the information on the acoustic wall impedance is required. In this article, a measurement technique that is valid over the low frequency range and without mean flow condition is presented. The measurement is performed in a cylindrical chamber with a concentric layout of the sample and the resistance is estimated from measured reactance and transmission loss data. It is observed that the measured transmission loss for a porous woven hose with an arbitrary length agrees well with the predicted one that uses the estimated impedance for a small sample length.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.21 no.10
• /
• pp.1648-1655
• /
• 1997

The intake noise, a major source of vehicle noises, has rapidly become a noticeable, and has been studied to reduce the level. Traditionally, the intake system has been developed through a experiment, namely, the trial and error process. This approach requires very high cost and long time consuming to develop the system. Recently, FEM and BEM are becoming useful in analysis of the intake system, and te results of analysis are very valid. But because these techniques also require high cost and long analysis time, these are generally not practical tool at the early stage of the development of an intake system. In this study, the software was developed to predict and analyze the acoustic characteristics of an intake system. It was based on the Transfer Matrix Method and operated to analyze a simplified intake system in a personal computer. It can be used early in the design stage of development of the intake system. This study presented an improvement to reduce the level of an intake noise. It was to select the optimum position of a resonator and verified by NIT/SYSNOISE, FE analysis commercial software, and testing a prototype.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.05a
• /
• pp.283-290
• /
• 2007

Recently, plastic products in air-intake parts of automotive engines have become very popular due to advantages that include reduced weight, constricted cost, and lower intake air temperature. However, flow-induced noise in air-intake parts becomes a more serious problem for plastic intake-manifolds than for conventional aluminum-made manifolds. This is due to the fact that plastic manifolds transmit more noise owing to their lower material density. Internal aerodynamic noise from an Idle Speed control Actuator (ISA) is qualitatively analyzed by using a scaling law, which is expressed with some flow parameters such as pressure drop, maximum flow velocity, and turbulence kinetic energy. First, basic flow characteristics through ISA passage are identified with the flow predictions obtained by applying Computational Fluid Dynamics techniques. Then, the effects on ISA passage noise of each design factors including the duct turning shape and vane geometries are assessed. Based on these results, the preliminary low noise design for the ISA passage are proposed. The current method for the prediction of internal aerodynamic noise consists of the steady CFD and the scaling laws for the noise prediction. This combination is most cost-effective, compared with other methods, and therefore is believed to be suited for the preliminary design tool in the industrial field.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.17 no.8
• /
• pp.683-692
• /
• 2007

Recently, plastic products in air-intake parts of automotive engines have become very popular due to advantages that include reduced weight, constricted cost, and lower intake air temperature. However, flow-induced noise in air-intake parts becomes a more serious problem for plastic intake-manifolds than for conventional aluminum-made manifolds. This is due to the fact that plastic manifolds transmit more noise owing to their lower material density. Internal aerodynamic noise from an idle speed control actuator(ISA) is qualitatively analyzed by using a scaling law, which is expressed with some flow parameters such as pressure drop, maximum flow velocity, and turbulence kinetic energy. First, basic flow characteristics through ISA passage are identified with the flow predictions obtained by applying computational fluid dynamics techniques. Then, the effects on ISA passage noise of each design factors including the duct turning shape and vane geometries are assessed. Based on these results, the preliminary low noise design for the ISA passage are proposed. The current method for the prediction of internal aerodynamic noise consists of the steady CFD and the scaling laws for the noise prediction. This combination is most cost-effective, compared with other methods, and therefore is believed to be suited for the preliminary design tool in the industrial field.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.8
• /
• pp.734-741
• /
• 2010

In this paper, an intake RCV system for low noise turbo engine was developed through optimization process of a geometric path of compressor housing and an open rate of recirculation valve. At first, the critical customer requirement from voice of customer was defined and quality function deployment of an intake RCV system was executed. And then, the renovative concept design using pugh matrix method was selected as final concept for satisfaction of requirement. Simultaneously, system analysis was carried by function diagram and fishbone diagram. Next, control factors and levels for the optimal design were performed. And, the optimal design of an intake RCV system was studied using design of experiment. Conclusively, we achieved not only cancellation tip-out noise at the driving condition but also improvement of NVH commodity through optimization process of an intake RCV system, which is optimal configuration of compressor housing and recirculation valve.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.1
• /
• pp.181-188
• /
• 2001

The evaluation of the noise for the an existing engine was carried out to improve the current noise level. The applied techniques were 1m air-borne noise, combustion noise analysis, torsional analysis at the front pulley and sound pressure intensity. In addition, the evaluation of the possibility to the noise reduction by means of wrapping the parts was performed to propose the detailed information in engine design. In view of the obtained results, the following countermeasures were recommended to reduce the current noise level through the above methods. Furthermore, in order to assess the influence of combustion noise on the overall engine noise, the noise test was also performed by the change of intake air temperature up to 5$0^{\circ}C$ in steps of 1$0^{\circ}C$. Finally, the fixed design specifications to reduce the engine noise will be decided in consideration of the test data for proto type engine.