• 한국자동차공학회논문집
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• 제5권6호
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• pp.167-174
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• 1997

The penetration depth and the size distribution of the droplets of fuel sprays are important in the operation of spark-ignition MPI engines. A fluorescence/scattering image technique for droplet sizing was applied to measure th edroplet size distribution in non-evaporating gasoline sprays. The fluorescence and scattering lights were imaged simultaneously by the two-dimensional visualization system composed of a laser sheet, a doubling prism, optical filters, and a CCD camera. Quantitative droplet size distributions were extracted from evaluating the ratio of the two light densities. The mean droplet size measured by the fluorescence/scattering technique was compared with the result obtained by the enlarged photographs of droplets. The fluorescence/scattering image technique also gives the useful information of the characteristics of droplet impingement in a inclined wall.

• 한국자동차공학회논문집
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• 제8권5호
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• pp.86-95
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• 2000

A modified spray impingement model has been developed, which is assessed against experiments for the impinging sprays on the small combustion chamber at various gas pressures. To investigate spray behaviors in the diesel combustion chamber, a transparent constant-volume chamber is made which is similar to the combustion chamber of the real diesel engine. The chamber is pressurized by N2 gas from 0 bar to 20 bar to find the effects of ambient pressures. The behaviors of spray injected into this chamber and dispersed after impingement on the cylinder wall is measured two-dimensionally using laser sheet Mie scattering method. The physical submodels have been properly modified to improve the prediction capability of original KIVA code to describe the spray behaviors after impingement on the curved cylinder wall. In terms of spray dynamics and evolution. numerical results give qualitatively good agreements with experimental data.

• 전기의세계
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• 제42권7호
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• pp.30-44
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• 1993

본 논단에서는 스마트 파워 IC의 개념과 주요 구성 핵심기술인 횡형 전력소자들의 기본구조와 특성을 비교하였으며, 공정에 밀접한 관련있는 전기적 격리기술, 그리고 스마트 파워 칩 구현을 위한 CAD체계에 대해 논의하였다. 또한 자동차 하이사이드 스위치와 모터 제어 및 구동용 스마트 파워 IC의 제품을 중심으로 스마트 파워 IC의 응용분야에 대해 간략하게 살펴보았다. 전자기기에 광범위하게 응용되어 시스템의 고급화, 고신뢰도 및 소형경량화에 중요한 반도체 소자를 포함한 전체 전력 반도체 소자 시장 50억불의 20%를 형성하였다. 최근 스마트 파워 IC의 큰 시트 파워 IC는 자동차 1대당 50개에서 140개까지 소요 예상되리라는 보고도 되고 있다. 스마트 파워 IC는 고내압, 대전류, 고속 스위칭 특성을 갖는 전력소자 및 전기적 격리기술 그리고 설계자동화를 위한 스마트 파워 IC의 구성 요소기술들의 지속적인 발전에 힘입어 더욱 고기능화된 제품개발에 의해 민생용 소비재 분야에서 산업분야까지 현재 보다 더 광범위한 응용이 기대된다.

• 한국자동차공학회논문집
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• 제13권4호
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• pp.160-166
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• 2005

In recent, recreational vehicles, which efficiently provide wide inner space for various utilities, are highly preferred in automobile market. Though those vehicles enable to load much luggage in space behind the last seat, in case of frontal impact with high velocity the luggage strongly collides into the seat back and the passengers in. the last seat could be severely injured. Therefore, high strength against luggage intrusion is required for the last seat, and it is regulated by law of ECE R17. In this study, for a recreational vehicle under developing, an analysis technique for simulating seat crash in accordance with luggage intrusion test of ECE R17 was investigated. The results exhibited good correlation with the test ones.

• 한국기계가공학회지
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• 제18권8호
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• pp.18-23
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• 2019

In this study, structural and fatigue analyses of the motor gears that control the height of car seat were carried out at angles of $10^{\circ}$, $20^{\circ}$, and $30^{\circ}$. The study aims at examining which angle of the gear is superior in terms of effect on strength. In the structural and fatigue analyses, the force of 3136 N was applied to the gears, and the stress and deformation were obtained. As the analysis results, model B ($30^{\circ}$) is suggested to have the best strength and fatigue durability among the three models.

• 한국자동차공학회논문집
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• 제22권6호
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• pp.104-112
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• 2014

Generally, numerical approaches of evaluation for vehicle seat comfort have been studied without considering time-dependent characteristics and the only seating moment have been considered in seat design. However, the comfort not only at the seating moment but also in the long-term should be evaluated because the passengers are sitting repeatedly on the seat to drive the vehicle for hours. So, the aim of this paper is to carry out a quantitative evaluation of the time-dependent mechanical characteristics of seat foams and to suggest a process for predicting the viscoelastic deformation of seat foam in response to long-term driving. To characterize the seat materials, uniaxial compression and tension tests were carried out for the seat foam and stress relaxation tests were performed for evaluating the viscoelastic behavior of the seat foam. A unit solid element model was used to verify the reliability of the material model with respect to the compression behavior of the seat foam. It is not straightforward to evaluate the time-dependent compression of foams using the explicit solver because the viscoelastic material model is limited. To use the explicit solver, the material model must be modified using stress-degradation data. Normalized stress relaxation moduli were added to the stress-strain curves obtained under static conditions to achieve a time-dependent set of stress-strain relations that were compatible with the implicit solver. There was good agreement between the analysis results and experimental data.

• 대한기계학회논문집A
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• 제24권7호
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• pp.1779-1786
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• 2000

Most of traditional design processes of mechanical parts are regarded as sequential and discrete, since different kinds of softwas should be introduced. In this paper, we develop an integrated fram ework for virtual design and performance testing of an automobile seat. The system is composed of four modules, i.e. CAD, static analysis, dynamic analysis, and draft drawing module. In the CAD module, PRO/ENGINEER 3D seat model is created using parameters to be modified with the result of static and dynamic analysis. In the static analysis, headrest tere used in each design stage make it difficult to feedback their results to upstream process. These discrete processes may result in time loss and cost rise. In recent years, life cycle of product is reduced. To have competence with others, new concept design processt is simulated using ANSYS. In the dynamic analysis module, FMVSS201 test is simulated using DADS. Overall data flow is controlled by Motif. The advantage of the system is that even a novice can perform and review the whole design process, without a good hand at professional design/analysis S/W in each stage. The system also provides a virtual design space, where engineers in different development stage can access common data of design models. The concept could be applied to other fields and it could reduce time and money required in design process.

• 한국자동차공학회논문집
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• 제17권3호
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• pp.110-116
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• 2009

Research for climate control seats is being vigorously pursued because requests for passenger's thermal comfort are increasing. Recently, thermoelectric devices have been applied to automotive seats for both cooling and heating operations. The climate control seats using thermoelectric devices can rapidly control the air temperature passing through the devices and directly affect the thermal comfort of passengers. The performance characteristics of the climate control seats were analyzed by experiments for two different types of a leather covered seat and a mesh applied seat. Experimental results show that the cooling and heating performance for the mesh applied seat by using the discharge port of the shape of nozzle was improved significantly in comparison with that for the leather covered seat. The variation of temperature between the inlet air and the outlet air of the climate control seat for the enhanced mesh applied type was by $-3.5^{\circ}C$ at cooling mode, and was by $15.0^{\circ}C$ at heating mode, after about 30 minutes, respectively. Also, it is possible to provide rapid thermal comfort to passengers sitting on the seat in the vehicle cabin by using the proposed climate control seat.

• 한국자동차공학회논문집
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• 제15권4호
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• pp.101-107
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• 2007

This study investigated the wear of the valve and seat insert seating faces. A tester, an exhaust valve and a seat insert were used. Test variables were cycle numbers ($2{\times}10^6,\;4{\times}10^6,\;6{\times}10^6\;and\;8{\times}10^6$) and Hz (10Hz and 25Hz). The other test conditions such as temperature ($350^{\circ}C$), fuel (LPG) and load (1960N) were fixed. The 10Hz tests indicated that the average Rmax of the valve increased at the rate of $7.76{\mu}m/10^6$ cycles starting from $29.42{\mu}m$ at the $2{\times}10^6$ cycles and that of the seat insert increased at the rate of $8.57{\mu}m/10^6$ cycles starting from $34.19{\mu}m$ at the $2{\times}10^6$ cycles. The 25Hz tests indicated that the average Rmax of the valve increased at the rate of $1.58{\mu}m/10^6$ cycles starting from $74.2{\mu}m$ at the $2{\times}10^6$ cycles and that of the seat insert increased at the rate of $1.25{\mu}m/10^6$ cycles starting from $83.95{\mu}m$ at the $2{\times}10^6$ cycles. The tribochemical reaction product covered the two seating faces, preventing the wear of the seating faces. As cycle numbers became greater, the average Rmax of the seating faces became greater, but the increase rate varied significantly depending on the Hz. The wear mechanism of the two faces was investigated through the tribochemical reaction.

• 한국기계가공학회지
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• 제18권2호
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• pp.29-37
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• 2019

In this study, emotional adjectives about the operating sound quality of the vehicle power seat are constructed, and the effectiveness of the emotional adjectives are verified by evaluating the operating sound quality. First, emotional adjectives were collected from the literature related to the automobile field and other sound qualities. A questionnaire was made using these adjectives. The questionnaire was designed to be able to select all adjectives that could express the operating noise of the power seat slide adjuster by applying the multiple- response method. Next, a subjective sound quality evaluation was conducted using the emotional adjectives. In the evaluation, we first recorded the operating noise for two power seats. Second, the subjective sound quality evaluation was performed on the recorded operating noise using a loudspeaker. Finally, through a statistical analysis on the sound quality evaluation results, the relationship between the semantic space and the preference score was verified, and the validity of the emotional adjectives was verified.