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경차의 비대칭 Defrost duct의 HVAC 성능 최적화에 대한 연구
강선제(Sunje Kang),김용년(Yongnyun Kim),송봉하(Bongha Song) 한국자동차공학회 2013 한국자동차공학회 학술대회 및 전시회 Vol.2013 No.11
This paper present a study about developing a defrost performance of the mini vehicle. Defrost performance of vehicle, specially de-ice performance is one of major contributed factor to safe driving on secure vision area view point. Major keys for secure vision area of a windshield are uniformity of airflow pattern at defrost duct outlet. Generally, a mini vehicle has small packaging area to place a HVAC(Heating, Ventilation and Air-Conditioning) module and ducts having symmetrical geometry. There are lots of restriction to develop HVAC module and ducts because of small space. Position and geometry of HVAC module and ducts have negative effect to have uniformity of airflow pattern at defrost duct outlet. For this reason, developing defrost performance in a mini vehicle is required lots of study. This study was performed by CFD CAE to optimize defrost duct design to secure uniformity of defrost duct outlet airflow pattern. Validation results between physical climate chamber test and CFD simulation result are also discussed. Results show well matched for a defrost performance development by CAE.
동일 Architecture의 서로 다른 외부 형상을 가진 차량들에 대한 공력 성능 개선을 위한 Roof spoiler개발에 대한 연구
김용년(Yongnyun Kim),강선제(Sunje Kang),김수경(Sukyung Kim),송봉하(Bongha Song),김용석(Yongsuk Kim) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
Developing and optimizing wake region of a vehicle rear end is important to secure Aerodynamic performance. Most of hatchback vehicle applies a roof spoiler to enhance Aerodynamic performance and specially, this roof spoiler is very important part in a Mini class vehicle having short vehicle length. This roof spoiler is reducing strength of rear wake zone and optimizing flow separation of a roof end to prevent increasing drag. To reduce investment cost in development of vehicles, Common architecture (platform) is applied to same dimensional vehicles or special purpose vehicle as like electric vehicle. And, also most of exterior part (for example, a hood, a side body, a roof, glasses, side doors, a tail gate, underbody structure, etc.) is applied to different vehicles. In these cases, flow field is possible to be changed for these two different vehicles and a roof spoiler should be developed separately. In this study, we can see difference of the Aerodynamic performance for a roof spoiler between same architecture vehicles having same dimension and same body, but having different exterior look. We conducted this study by Aerodynamic wind tunnel test and CFD CAE simulation.
쉐보레 스파크 전기 자동차(Electric Vehicle)의 공력성능 개발
김용년(Yongnyun Kim),강선제(Sunje Kang),최은수(Eunsoo Choi) 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5
This paper presents a study about developing the Aerodynamic characteristics of the Spark EV(Electric Vehicle). Aerodynamics of an electric vehicle, specially drag property is one of major contributed factor to enhance driving range capability. Major keys for good driving range capability of an electric vehicle are performance of driving unit, battery capacity, vehicle mass, and Aerodynamics of a vehicle. The Spark EV is developed using the architecture of the Spark 2012 that is applied an internal combustion engine (ICE). The Spark EV shares all component and body structures with the Spark 2012 except exterior styling and electric components (Driving unit, battery related parts). There were lots of restrictions to improve the Aerodynamic performance of this Spark EV because the body shape and the architecture are shared with current production of the Spark vehicle. For this reason, Aerodynamic development of the Spark EV is focused on optimized cooling flow, additionally attached components and modifying exterior shape. The Spark EV is applied active shutters to control cooling flow, full underbody panels to have less drag on underbody structures, and the optimized new roof spoiler and the rear fascia to have good flow separation. This study was performed by CFD CAE to optimize front end airflow and exterior flow field, and wind tunnel test to find and develop enablers for Aerodynamics.
차량 외부 디자인 단계에서 경차의 전면 개구부 설정을 위한 Kringing method를 통한 유입 유량과 공력 성능에 대한 연구
김용년(Yongnyun Kim),강선제(Sunje Kang),김수경(Sukyung Kim),권우성(Woosung Kwon),하종백(Jongpaek Ha) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
Definition of Front End Opening is main development factor to develop vehicle exterior design and vehicle performance for Aerodynamics and powertrain cooling. This front opening definition has to be applied in early design development stage. And required opening area based on vehicle performance condition should be reflected to this definition. This opening is key factor for styling and engineering design to meet styling needs and performance requirement. In terms of vehicle performance, this opening is area to supply cooling airflow (FEAF, front end airflow) for powertrain and a factor to generate drag in engine room compartment. This study is to develop a method to optimize front end opening and to develop a prediction tool and supply a tool to design studio to meet each requirement by Kriging method that is one of DFSS tools.
LIVC 적용 밀러사이클 스파크점화기관의 유동특성 연구
정진호 ( J. H. Chung ),강선제 ( S. J. Kang ),김진수 ( J. S. Kim ),정석철 ( S. C. Jeong ),이진욱 ( J. W. Lee ) 한국분무공학회 2016 한국액체미립화학회지 Vol.21 No.1
In this study, to research in-cylinder flow characteristics of spark-ignited engine with intake valve closing timing change for Miller cycle. 3D simulation study were used 6 different intake valve profile with CAD10° gap for retard intake valve closing timing. Comparison of In-cylinder flow pattern characteristic were accompanied between Base and LIVC. And the efficiency of volume and the work of compression were analyzed with simulation study. When intake valve closing angle was retarded in CAD50°, the pressure in cylinder was decreased about 12~13 bar and volume efficiency was reduced about 16%. The efficiency of volume and the work of compression were reduced on LIVC.
밀러사이클 적용 스파크점화기관의 후기 흡기밸브 닫힘각 변화에 따른 연소성능 연구
정진호 ( J H Chung ),강선제 ( S J Kang ),김진수 ( J S Kim ),정석철 ( S C Jeong ),이진욱 ( J W Lee ) 한국액체미립화학회 2015 한국액체미립화학회지 Vol.20 No.3
In order to research engine characteristics of spark-ignited engine with intake valve closing timing change for Miller cycle, two cam for LIVC (Late Intake Valve Closing) were designed and fabricated an prototype valvetrain. And intake valve closing timing were adjusted to build low compressing and high expansion cycle for HEV. In experimental study, it were investigated with different engine speed, spark timing and air-fuel ratio to compare base cam and LIVC cam type. It was found that the volumetry efficiency and effective work of compression process were decreased in case of LIVC cam. When compared with the existing results, the maximum pressure in the cylinder was reduced about 12~13 bar and the volumetric efficiency was reduced about 16%.
김용년(Yongnyun Kim),강선제(Sunje Kang),송봉하(Bongha Song),김용석(Yongsuk Kim) 한국자동차공학회 2015 한국자동차공학회 학술대회 및 전시회 Vol.2015 No.11
This paper presents the development on the Aerodynamic performance of the 2016 Chevrolet the Next Spark. This 2016 Spark is fully changed on the exterior styling and the architecture comparing from its previous version released in 2009 and it was conducted to improve Aerodynamic performance to support fuel economy and fuel consumption. To reduce the drag of the 2016 Spark, Exterior skin is fully optimized to have best Aerodynamic performance. And several Aerodynamic treatments are applied such as flat underbody, low leakage for cooling flow, and add-on Aerodynamics devices. Biggest contribution on drag of the vehicle is coming from exterior surface and underbody shape. This 2016 Spark was developed to have better drag coefficient on these exterior surface and underbody shape. For reducing drag on the exterior surface, it was conducted to optimize the exterior surface cooperated with Exterior studio from early development stage. In this development, Aero was involved from proportion development of the vehicle and theme development. This new vehicle is able to get 58 counts drag reduction from its initial styling model. And for reducing drag on the underbody structure, this vehicle is applied not to have vertical wall on the underbody structure decreasing pressure load. General vehicle and previous version of the Spark have vertical wall on the underbody structure against flow direction to support vehicle safety, but this 2016 Spark is adopted and designed flat underbody structure considering not hurting vehicle safety in early stage of development. This concept was contributed to reduce drag on the underbody structure. Also, this vehicle is developed low leakage cooling flow between the grill and the radiator. The 2016 Spark is reduced 8% - 19% in each powertrain variant comparing to the previous version. This improved cooling flow leakage contributes drag reduction decreasing non-effective flow goes into the engine room. And this vehicle adopted the enhanced airdam, Aerodynamic friendly OSRVM, D-pillar applique integrated roof spoiler, and edged side corner on taillamp, etc. In this development, Aero spends 344 hours for wind tunnel test of the 2016 Spark. And, there was 38 simulation runs for Aero CFD analysis and there was 5 times architecture change reflecting changed body structure. This development was supported to reduce drag 8.3% from the previous Spark and the 2016 Spark is able to lead Aerodynamic performance in the A segment.