• International Journal of Automotive Technology
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• 제7권1호
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• pp.43-49
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• 2006

In this paper, an index for the evaluation of a vehicle intake booming noise and intake sound quality were developed through a correlation analysis and a multiple factor regression analysis of objective measurement and subjective evaluation data. At first, an intake orifice noise was measured at the wide-open throttle test condition. And then, an acoustic transfer function between intake orifice noise and interior noise at the steady state condition was estimated. Simultaneously, subjective evaluation was carried out with a 10-scale score by 8 intake noise and vibration expert evaluators. Next, the correlation analysis between the psychoacoustic parameters derived from the measured data and the subjective evaluation was performed. The most critical factor was determined and the corresponding index for intake booming noise and sound quality are obtained from the multiple factor regression method. And, the optimal design of intake system was studied using the booming noise and the sound quality evaluation index for expectation performance of intake system. Conclusively, the optimal designing parameters of intake system from noise level and sound quality whose point of view were extracted by adapting comparative weighting between the booming noise and sound quality evaluation index, which optimized the process. These work could be represented guideline to system engineers, designers and test engineers about optimization procedure of system performance by considering both of noise level and sound quality.

• 한국농공학회지
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• 제30권3호
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• pp.82-94
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• 1988

A growing attention has been paid to the optimum design of structures in recent years. Most studies on the optimum design of reinforced concrete structures has been mainly focussed to the design of structural members such as beams, slabs and columns, and there exist few studies that deal with the optimum design of large-scale concrete shell structures. The purpose of the present investigation is, therefore, to set up an efficient optimum design method for the large-scale reinforced concrete cylindrical shell structures like intake tower of reservoir. The major design variables are the dimensions and steel areas of each member of structures. The construction cost which is compo8ed of the concrete, steel, and form work costs, respectively, is taken as the objective function. The constraint equations for the design of intake-tower are derived on the basis of strength design method. The results obtained are summarized as follows 1. The efficient optimlzation algorithrns which can execute the automatic optimum design of reinforced concrete intake tower based on the strength design method were developed. 2. Since the objective function and design variables were converged to their optimum values within the first or second iteration, the optimization algorithms developed in this study seem to be efficient and stable. 3. When using the strength design method, the construction cost could be saved about 9% compared with working stress design method. Therefore, the reliability of algorithm was proved. 4. The difference in construction cost between the optimum designs with substructures and with entire structure was found to be small and thus the optimum design with substructures may conveniently be used in practical design. 5. The major active constraints of each structural member were found to be the 'bending moment constraint for slab, the minimum longitudinal steel ratio constraint for tower body and the shearing force, bending moment and maximum eccentricity constraints for footing, respectively. 6. The computer program developed in the present study can be effectively used even by an uneiperienced designer for the optimum design of reinforced concrete intake-tower on the basis of strength design method.

• 오토저널
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• 제14권5호
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• pp.69-82
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• 1992

Vibration of intake menifold is important as it could worsen the noise levels radiated from surface itself and support bracket, and it eventually leads to the failures of a Throttle Position Sensor and an Idle Air Control Valve. In this study, structural modification method is proposed to reduce structural vibration of an intake manifold system. At first, vibration problems are identified through tests on a running engine. Then modal data acquired by modal testing and finite element analysis are helpful to understand vibration mechanism of the system, and used as the design guide when structural modifications are attempted. After the system model is validated by comparison of the modal data obtained from analysis and experiment, iterative calculations are performed to find optimized structure of the system by finite element analysis. As a result, a newly designed plenum bracket is suggested in such a way that the intake manifold is stiffened, and that design of the support bracket is suggested in such a way that the intake manifold is stiffened, and that design of the support bracket is changed in terms of bolting position, thickness, shape, and minimum weight increase. Finally, it is shown that a new design achieves a significant reduction of vibration of an intake manifold system and it is confirmed by tests on a running engine.

• 한국항공우주학회지
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• 제47권3호
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• pp.195-203
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• 2019

극초음속 영역에서 운용되는 스크램제트엔진의 흡입구는 엔진 전체 성능에 직접적으로 연관되어 있으므로 개발에 앞서, 다양한 조건에서의 성능 특성 분석이 필수적이다. 본 연구에서는 축대칭 내부 압축형 흡입구인 Busemann과 외부 압축형 흡입구 형상을 설계하고, 설계점 및 탈설계점에서의 전산해석을 수행하였다. 해석결과를 토대로, 마하수와 받음각에 대한 극초음속 흡입구의 전반적인 성능 특성을 파악하였다. Busemann 흡입구는 $2^{\circ}$의 Truncation 각에 따라 흡입구의 길이를 단축하여도 성능 저하가 미미하였으며 탈설계 마하수에서는 흡입구 성능이 우수하였으나, 받음각이 있는 경우 시동 특성이 크게 저하되었다.

• 한국자동차공학회논문집
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• 제5권3호
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• pp.47-53
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• 1997

The importance of intake system can not be overstressed in the recent heavy duty commercial vehicle design. The basic requirements of intake system are to have less flow resistance and better air cleaning performance which have direct effects on the performance and service life of engine. In order to improve the performance of engine intake system, the flow phenomena in the intake system should be fully understood. With readily availble CFD code, the numerical analysis becomes the more reliable tools for flow optimization in recent design work. In this research, flow field in the intake system was analyzed by STAR-CD, the 3-D computational fluid dynamics code. Especially, the flow inside of air cleaner was thoroughly analyzed. Pressure distribution and velocity profile in the air cleaner and intake duct was obtained. Having the dust seperated from incoming air at the expense of less pressure drop is the ultimate goal for the research.

• Journal of Advanced Marine Engineering and Technology
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• 제22권6호
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• pp.836-843
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• 1998

In this paper effects of resonator within intake manifold system on volumetric efficiency were investigated n the 4-cylinder and 4 stroke Diesel Engines. The effects of resonator system were analyzed on resonant speed and on volumetric efficiency for a complicated intake system with resonator was confirmed. And the optimum design method of the resonant system which had the overall high and flat characteristic of volumetric efficiecncy was proposed.

• 한국전산유체공학회지
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• 제17권2호
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• pp.58-64
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• 2012

Turbulent flows in a intake part of vacuum cleaner are studied by RANS simulations. The governing equations are solved by the SIMPLE algorithm based on the finite volume method of the unstructured grid system. The predicted results show that the suction performance is closely related to the variation of flow structure in the intake part. In order to investigate for the cleaning of bedclothes and carpet without sticking, several design changes are applied. The introduction of a solid cylinder in the intake part changes vortical structures significantly. Based on this result, a new design with spiral brushes is proposed. The design shows a good behavior for the suction performance and the flow control.

• 소음진동
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• 제11권2호
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• pp.234-240
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• 2001

Recently, the regulations from the government and the concerns of people be raised 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 this paper. 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 be effective to the performance of intake system was selected. At first, factors are arranged by using Ll8 table of orthogonal array and then optimum value can be obtained by modified Ll6 table of orthogonal array.

• 한국추진공학회지
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• 제18권6호
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• pp.1-10
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• 2014

극초음속 흡입구를 직관적이며 체계적으로 설계할 수 있는 최적화된 방법을 제시한다. 마하 7의 이론식으로 계산된 극초음속 흡입구는 점성 조건의 전산수치해석을 수행하여 점성에 대한 오차를 보정한다. 전산수치해석을 통한 성능 비교에서 1단 쐐기에 비해 2단 쐐기를 가지는 흡입구 형상이 성능비교에서 좋은 결과를 보였다. 또한 비설계 조건에서 극초음속 흡입구의 성능은 설계 마하수 성능에 비해 손실이 크지 않았다.

• 대한기계학회논문집A
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• 제21권10호
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• pp.1656-1665
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• 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 systm. Recently, FEM and BEM are becoming useful in analysis of the intake system, and the results of analysis are very valid. But because this techniques also require high cost and long analysis time, this technique is generally not practical tool at the early stage of the development. In this study, the software was developed to predict and analyze the acoustic characteristics of the 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 a improvement to reduce the level of the intake noise, which modified the specification of the intake system. And the improvement were verified by NIT/SYSNOISE, FE analysis commercial software, and testing a prototype.