• 한국융합학회논문지
• /
• 제12권1호
• /
• pp.171-176
• /
• 2021

본 연구에서는 자동차 머플러의 형상별 유동해석을 수행하여 가장 유동성을 증가할 수 있는 설계 모델을 찾는 데에 있다. Model B가 최대 압력이 비교적 가장 작게 나오고 Model C가 가장 크게 나왔다. 자동차의 머플러 형상에 따른 최고의 유동 속도를 비교하면 Model A가 비교적 입구 및 출구에서의 유동의 흐름이 원활했다. 그러나 Model B는 머플러 내에서의 유동 속도는 크지만 출구에서는 유동 속도가 가장 적어져서 유동의 효율성은 떨어져 보인다. 머플러의 형상에 따른 유동 해석 결과에 의하여 좀 더 유동이 원활한 모델을 찾음으로서 머플러를 효율적으로 설계할 수 있다고 사료된다. 본 연구 결과를 이용하면 실제 실험을 하지 않아도 소형 자동차의 머플러 형상에 따른 유동을 조사할 수 있다. 또한 소형 자동차의 머플러의 미적인 융합 설계에 도움이 될 수 있다고 보인다.

• 한국인터넷방송통신학회논문지
• /
• 제19권4호
• /
• pp.47-54
• /
• 2019

전세계적으로 기후 변화의 영향에 따른 차량 추돌 사고에 대한 위험성이 중요한 이슈로 등장하고 있다. 고속주행차량의 속도제한을 위해 다양한 형태의 속도제한 표시장치가 고려되고 있으나 현재는 대부분 고정식 속도제한 표시기를 사용하고 있다. 4계절이 뚜렷한 우리나라의 경우에는 비가 많이 오는 우기나 눈이 많이 오는 계절이나 안개가 많이 발생되는 경우에는 차량 추돌 사고를 방지하기 위한 차량 속도 감속 제한이 필요하지만 기존에 설치되어 있는 고정식 표지판으로는 사고를 미연에 방지하는 것이 어려운 실정이다. 본 연구에서는 레인 센서와 차량 와이퍼 시스템 등을 결합 시킨 기후 변화에 따른 차량 속도 제한이 가변적으로 표시되는 LED 전광판의 프로토타입 모델을 제작하였다. 내리는 비나 눈의 양에 따라 기준속도의 100%, 80%, 50%로 3단계로 가변 표시되는 속도제한 표시기는 설치되는 장소에 따라 적절한 속도를 선택 지정하여 표시할 수 있다. LED 표시장치를 이용한 시각적인 효과로 인해 운전자들이 사전에 속도를 감속하게 하여 차량 추돌 사고를 미연에 방지하는데 효과적으로 이용될 것으로 기대 된다.

• 항공우주시스템공학회지
• /
• 제4권2호
• /
• pp.10-15
• /
• 2010

Aerodynamic noise is becoming the major source of annoyance for modern cars recently and is caused by many different noise sources in a car. Appropriate CFD technologies, therefore, have been developed to resolve the noise problems related with aerodynamics. It is necessary for designers to fully understand the relationship between vehicle aerodynamics and wind noise acoustics. In this study, we simulate the flow fields around two different shapes of side mirror models of passenger car and analyze the noise phenomena around one side mirror model that has lower drag than the other model using Fluent 6.3.

• 소음진동
• /
• 제9권4호
• /
• pp.785-794
• /
• 1999

The panel contribution analysis to reduce interior booming noise of a passenger car is carried out using both experimental method and numerical one. The accelerations of panels are measured on the outer surface of car body during operation. The acoustic characteristic of cavity is represented by two different ways. One is the acoustic transfer function obtained by experiment with reciprocal manner. The other is the boundary element model and numerical results of the model are calculated using SYSNOISE. The results from numerical method show more good agreement with measured sound pressure levels than the experimental one. Contributions of panels for interior noise are ranked and structure of the car is reinforced according to the results, which shows that the panel contribution analysis is a powerful tool to lessen structure-borne noise of passenger vehicle.

• Tribology and Lubricants
• /
• 제18권6호
• /
• pp.384-388
• /
• 2002

The adequate design of a passenger car braking system, which is directly related to the safety of a car, is very important since the safety is an essential design parameter of a car to keep men and car from the damage. The thermal behaviors of the ventilated disk has been investigated based on the air cooling effects during repeat braking operations. In this study, the thermal behavior of ventilated disk brake system was investigated by numerical method. The 3-Dimensional unsteady model was simulated by using a general purpose software package “FLUENT” to obtain the temperature distributions of disk and pad. The model includes the more realistic braking method, which repeats braking and release. The effects of aspect ratio of ventilated hole on the heat dissipation was investigated.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.166.3-166
• /
• 2001

This paper presents a modeling and control method of active suspension system with full-car model by using H$\infty$ control theory. The full-car model has seven degree of freedom including heaving, pitching and rolling motions. As the control method, H$\infty$ controller is designed so as to guarantee the robustness of closed loop system under the presence of uncertainties and disturbances. Active system with H$\infty$ controller can reduce the accelerations of the car-body in the heaving, pitching and rolling directions. The effectiveness of the controller is proved through simulation results in both time and frequency domains.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 춘계학술대회논문집
• /
• pp.1232-1240
• /
• 2001

In this study. a computer simulation of the Korean High Speed Prototype Test Train was performed to investigate the dynamic behavior(running stability. safety and comfort) in detail design process. The simulation model which was prepared by ADAMS/Rail V10.l consists of power car and middle car assembly (2 motorized cars ＋ 3 trailer cars). The nonlinear analysis takes into account the full vehicle model including wheel/rail contact and the influence of disturbed track. Throughout the dynamic calculation of KHST on the straight and the curved track. accelerations in car body. ride comforts and wheel rail forces were investigated.

• 한국자동차공학회논문집
• /
• 제5권2호
• /
• pp.31-41
• /
• 1997

Equations of motion for a 7 DOF full car model is developed in detail and used for the design of LQR based active suspension system. The frequency response to road disturbance input and the motion of a car passing unequal bumps were used to analyzed the dynamic characteristics of the 7 DOF full car with passive or active suspensions. The resulting linear equations of motion may be usefull in designing other types of active suspension.

• 한국자동차공학회논문집
• /
• 제5권3호
• /
• pp.66-75
• /
• 1997

Sound transmission from the luggage comparment into the car cabin is important in the viewpoint if exhaust and road noises of passenger cars. In this paper, acoustic modal coupling between passenger and luggage compartments through loudspeaker holes at parcel shelf is dealt with for a sedan type passenger car with rigid rear seat. For these purposes, a half-scaled model car is tested and computed by the indirect BEM. Predicted acoustic transfer functions are compared with experimental ones and they agree reasonably well. It is found that the fore-aft resonance frequencies of the passenger cavity in the absence of coupling holes are tend to shift to higher frequencies when the luggage compartment is coupled to the passenger cavity.

• 산업기술연구
• /
• 제9권
• /
• pp.87-99
• /
• 1989

It is desirable to predict the noise and vibration problems of a passenger car in its design stage for a better ride quality. Dominant frequencies of the noise inside a car range from about 50 Hz to 300 Hz and these are frequently caused by the coupling of the acoustic normal modes of the compartment cavity and structural modes of the body. In this paper, car interior noise problem is investigated in view of vibration-acoustic modes coupling and numerical simulation is performed on the interior noise. In the simulation, experimental modal data of the vehicle structure are utilized to improve the accuracy of the analysis. The results are in good agreement with those of experiment on a half scaled vehicle compartment model. Especially, strongly coupled modes can be predicted, which give useful informations to solve noise problems of real car at design stage.