PURPOSES : This study defines private and public service providers connected to a public data hub in a smart city and examines the information that should be exchanged between them. The information exchange scheme covers data exchange at a minimum level. METHODS : First, we reviewed the entities participating in the emergency charging service and designed the scope of information linkages between the entities. Second, we diagnosed the main information linkages according to a service flowchart. Third, we reviewed the basic information requirements linked to actors participating in the service. Finally, we derived and presented information linked to the subjects. RESULTS : In addition to the basic requirements, the number of data-exchange information sets specified was four, which was the scope of the aforementioned study. We defined and analyzed an efficient information exchange system between various actors involved in emergency charging services. Data were defined based on interactions between service users, operators, providers, and data hubs. Each set had a different scope and purpose. CONCLUSIONS : Information collected and provided by emergency charging service providers in connection with a data hub that manages urban energy was proposed.

This research studied faults that may occur during slow charging using the J1772 adapter of Tesla Model-3 electric vehicles. When the AC terminal was instantaneously disconnected, charging was performed normally when an AC circuit with disconnection up to three disconnection times was connected. Charging control was suspended when the number of disconnection reached four times. However, if the AC disconnection time exceeded 22 seconds, the charging control was stopped regardless of the number of disconnection. When a contact failure occurred at the AC terminal, high surge current and noise occurred. However, when the contact improved, the charging control continued. In terms of safety, it seems necessary to take measures such as stopping charging control when detecting noise.

When the CP voltage is disconnected, the measured voltage on the ICCB side is measured to be 12V, and the voltage on the OBC side is measured to be 0V. When the PD signal was disconnected, the ICCB-side measured voltage was 0V and the OBC-side measured voltage was 4.5V. From this, disconnected position be found with the voltage value measured. When CP was disconnected for a short time, the PD voltage did not change to 1.5V, and when the PD was disconnected, the CP signal and PD signal changed to 9V, and if the CP and PD voltages were normal, the charge control could be performed normally.

밀러 사이클은 흡입밸브 닫힘 시기 조정을 통해 압축비를 줄임으로써 NOx의 저감과 연료소비율 개선이 동시에 가능하다는 점 (밀러 효과)에서 디젤엔진에 매우 활발하게 채택되어지고 있다. 밀러 사이클은 흡입 밸브를 BDC 이전에 닫는 Early 밀러 방식과 BDC 이 후에 닫는 Late 밀러 방식으로 나눌 수 있다. 저속에서는 체적효율의 증가를 꾀할 수 있는 Late Miller가 유리한 반면, 중속, 고속에서는 IVC 이후 BDC 까지의 피스톤 하강 과정의 흡기의 팽창에 따른 내부 온도 감소 효과 높은 Early 밀러가 유리하다. 따라서 Early 밀러와 Late 밀러의 효과를 고려하여 운전 조건에 적합한 밀러 구현 방법을 채택할 필요가 있다. 본 연구에서는 4행정 엔진을 대상으로 2단 과급 시스 템의 적용하고 흡·배기 밸브 오버랩(valve overlap)의 감소를 통해 밀러 효과를 강화하는 과정과 밸브 조정 기구를 통한 밸브 조건의 변화 가 밀러 효과에 미치는 영향을 고찰하였다. 결과적으로 2단과급과 밀러사이클, 밸브 오버랩 감소와 흡입밸브 리프트 증가를 통해 연료소 비율과 최고연소온도 감소의 효과를 확인하였다.

전기자동차의 상용화시대에 대비한 전기자동차 충전네트워크가 시급해지고 있다. 해외에서는 주차장에 PV시스템을 설치하여 얻어진 전력으로 전기자동차 충전을 할 수 있는 전기자동차 충전소가 설치되어지고 있다. 또한 우리나라에서도 충전인프라 구축방안 및 전기자동차 충전시설 지원기준 등을 설정하여 제시하고 있지만 해외처럼 PV시스템을 이용한 전기자동차 충전소의 사례가 국내에는 없으며, 일반전력을 이용한 전기자동차 충전소만 제시하고 있다. 따라서 본 논문에서는 국내의 전기자동차 충전네트워크 구축에 대비하여 국내 외 태양광 주차장과 해외 PV시스템 전기자동차 충전소의 사례를 조사하여 구조시스템, 구조 재료 등을 분석하여 비교 분석한 결과, 해외 PV시스템 전기자동차 충전소의 경우 캔틸레버 구조와 소규모 타입이 많이 설치되었다.

HFC-134a is currently used as a refrigerant in automotive air conditioning system replacing the ozone depleting CFC-12 refrigerant. This paper was experimentally studied on the performance characteristics of an automotive air conditioning system with variations of charging refrigerant and compressor speed. An air conditioning system was composed of laminated type evaporator, parallel flow type condenser, vane rotary type compressor, externally equalized thermostatic expansion valve and receiver drier with specifications of Hyundai Sonata Ⅱ vehicle. And the automatic measuring system of air conditioner used KTE-1000BA developed by a KT ENG Co., Ltd.. of Korea. The optimum conditions which were tested as available parameters for better performance are indicated charging refrigerant 800 g and compressor speed 1700 rpm.