Earticle

본 연구에서는 자동차 엔진에 적용되는 고무마운트의 성능을 극대화하여 시동초기 진동특성를 개선하기 위해 능동형 하이브리드 마운트를 제안하고 진동절연 성능을 실험적으로 고찰하고자 한다. 제안된 하이브리드 마운트는 수동 형 고무요소와 능동형 압전작동기로 구성되었으며, 동적 특성과 제어력의 실험적 고찰을 통해 하이브리드 마운트가 제 작되었다. 수직방향의 진동을 고려하여 관성질량을 갖는 압전-고무 하이브리드 마운트의 동적 지배방정식을 수학적으 로 모델링하였으며 상태 공간 방정식으로 표현하였다. 본 연구에서는 진동을 절연하기 위해 강건한 슬라이딩 모드 제어 기가 구성되어 진동제어 실험에 적용되었다. 마지막으로 넓은 주파수 영역에서 진동제어 성능을 실험적으로 고찰하였으 며 주파수 영역에서의 전달율과 시간영역에서 진동절연 성능을 평가하였다.

A hybrid mount featuring rubber element and piezoelectric actuator is devised to reduce vibration when starting a vehicle engine. As a first step, a passive mount adopting rubber element is manufactured and its dynamic characteristics are experimentally evaluated. After evaluating dynamic characteristics of the manufactured inertial piezoelectric actuator, the proposed hybrid mount is then established by integrating the piezoelectric actuator with the rubber element for performance improvement at non-resonant high frequencies. A mathematical model of the established active vibration control system is formulated and expressed in the state space form. Subsequently, sliding mode controller (SMC) is designed to attenuate the vibration transmitted from the base excitation. Finally, control performances of the proposed hybrid mount are evaluated such as transmissibility in frequency domain and time responses.

방산기술이 복제되거나 방해기술이 발달되어 그 가치와 효용이 낮아지는 것을 방지하고 부적절한 수출을 방지하기 위한 보호가 필요하여 2015년도에 방위산업기술보호법이 제정되었다. 방산기술이란 방위산업과 관련된 국방과학기술 중에 서 국가안보를 위하여 보호되어야 하는 기술을 의미한다. 그러나 현재 방산기술 보호체계 중에서 보호대상 기술의 식별 및 관리 체계의 기술식별 기준이 법규화 되어 있지 않다. 이에 본 연구에서는 델파이 설문을 통하여 141개 방산기술 중에서 고효율 내연기관 추진 기술과 관련 있는 디젤기관 요소기술 식별기준을 정립하고 방산기술 보호체계 중 보호대상 기술의 식별 및 관리 체계를 개선하였다. 연구결과로 디젤기관 요소기술 식별기준으로 작전 운용성, 내구성, 안전성, 계열화 및 모듈화 등을 정립하였다.

The Defense Technology Security Act was enacted in 2015 to protect the defense industrial technology from being duplicated or interfering technologies being developed, which prevents its value and utility from deterioration and prevents inappropriate export. Defense industrial technology refers to technology that should be protected for national security among the national defense science and technology related to the defense industry. However, technical identification criteria of identification and management system of protection technology are not regulated. Therefore, in this study, through the Delphi survey, diesel engine core technology identification criteria related to the high efficiency internal combustion engine propulsion technology among the 141 defense industrial technologies is established to improve the identification and management system of the technology to be protected among the defense industrial technology protection system. As a result of the study, operational operability, durability, safety, sequencing and modularization were established as diesel engine core technology identification criteria.

This study is designed to measure the impact of a car’s horse power and torque - aspects related to performance among various factors that affect consumer purchase decision-on consumers when buying a car. The research of the results can be interpreted as indicating that the premise, “The impact of torque and horsepower on consumer purchase decision is not significant,” is true.

군에서는 디젤엔진차량을 주로 운용하고 있다. 고효율, 친환경으로 여겨지던 디젤엔진은 환경·안전 문제로 사회적 이슈가 되고 있다. 이런 디젤엔진의 문제를 고려하여 가격, 경량 화, 소음 측면에서 유리하고 배출되는 환경 오염물질이 적은 가솔린엔진차량을 군에서도 운용할 필요가 있다. 하지만 가솔린엔진은 연료 효율 측면에서 디젤엔진에 비해 좋지 않다. 이런 가솔린엔진의 단점을 극복하기 위해서는 연비를 개선시키는 기술을 적용하여 효과적 인 작전운용 수행을 위한 주행거리를 확보해야 한다. 본 연구에서는 군에서 운용중인 차량 중 가솔린엔진이 적용 가능한 차량을 선정하였다. 가솔린엔진에서 연비에 주요하게 영향을 미치는 흡기저항손실(Pumping Loss)을 줄이는 기술인 가변밸브리프트(Variable Valve Lift) 와 비활성실린더(Cylinder De-activation) 기술을 분석하였다. 이 분석을 바탕으로 더 많은 흡기저항손실을 줄이기 위해 가변밸브리프트와 비활성실린더 기술을 결합한 밸브제어 시스 템과 제어전략을 연구하였다.

Diesel engine vehicle are operated mainly in the military. Diesel engines, considered highly efficient and environmentally friendly, are becoming a social issue due to environmental and safety problem. Considering the problems of diesel engines, the military needs to operate gasoline engine vehicles that are advantageous in terms of price, light weight , noise and have low emissions. However, gasoline engines are not as good as diesel engines in terms of fuel efficiency. In order to overcome the shortcomings of the gasoline engine, fuel efficiency technologies should secure to provide a driving distance for effective operation performance. In this study, we selected a vehicle that can be operated with a gasoline engine in the military. Analysis was done on VVL(Variable Valve Lift) and CDA(Cylinder De-activation) technologies, which are techniques that reduce the pumping loss that significantly affects fuel economy in gasoline engines. To reduce more air pumping loss, a valve control system and control strategy that combined VVL and CDA technologies were studied.

Increasing specific power, torque and high responsibility have come to the fore as the importantstrategy of reducing fuel consumption in vehicle engines. Therefore, the boosting performance of variousboosting devices has been investigated using a diesel engine simulation program. For the comparison ofboosting performance, the simulation result of a naturally aspirated 2.0 liter engine is used as a basis. Subsequently, the boosting effects of single turbocharger, single supercharger and 2-stage boosting systemcombined with a turbocharger and a supercharger are compared at the same engine condition. Thesimulation results show that the 2-stage boosting system can attain lower specific fuel consumption andhigher air mass flow. In low engine speed range, a supercharger mainly leads higher boostingperformance with higher responsibility in the combined boosting system.

본 논문은 두 가지 영상 이벤트 신호로 제어되는 실시간 차량하부 검사 엔진에 대해 제안한다. 첫 번째 영상 이벤트는 차량 번호판인식에 의한 과정으로 생성된 것이고, 두 번째 영상 이벤트는 차량 하부 특정 이벤트 검출에 의해 생성된 것이다. 실험 결과, 두영상 이벤트 모두 2.8초, 1.1초로 실시간 처리에 적합하게 발생되는 것을 확인할 수 있었고, 이러한 영상 이벤트가 시스템의 제어체계로 사용되어 후부에 연결되는 다음 대응 상황에 적합한 신호를 보내주는 것으로 확인할 수 있었다.

In this paper, we presented Under Vehicle Inspection System by comparing two image signals. Two signals are generated by license plate number and under-vehicle pattern recognition. The test shows reliable precision within real-time of 2.8sec, which can be applicable commercially. In the future, more research will be conducted to enhance the precision by automatic image balance in many challenging situations.

In this paper, based on the existing research, we define the parameters for the number of ignition devices to be applied to the pyrovalve, the operation and airtightness according to the temperature, the material of the nipple and the thickness of the fractured part, and ANSYS Ver. 19.2 was used to analyze the FEA model, and a comparative analysis was conducted through structure analysis according to the piston shape of the pyrovalve. In addition, an experimental study was conducted by manufacturing a prototype according to the design variables. As a result, high-strength pyrovalves can stably supply working fluids such as fuel and oxidizer for space launch vehicle propulsion engines, as well as precisely control flow path switching was confirmed.

In case vehicle system has low travel distance and short duration of engine operation, this can be relatively susceptible to engine scuffing related problem. Users also experience inconvenience in system maintenance that they have to manually start engine periodically in cold night during winter. In order to solve such problems and improve system's life cycle, the automatic engine start system is developed. In order to develop the automatic engine start sytem for air defense system BIHO, two types of engine start sytem and the engine sub system are studied and four steps to start and control the automatic engine start system is suggested. The prototype of automatic engine start system was tested for the single assembly and vehicle-installed test and all requirement of the system was madeto prove its possible application.

In a bi-fuel engine using gasoline and LPG fuel, with the current ignition timing for gasoline being used, the optimum performance could not be taken in LPG fuel supply mode. The ignition timing in LPG fuel mode must be advanced much more than that of gasoline mode for the compensation of its higher ignition temperature. The purpose of this study is to investigate how the ignition spark timing conversion influences the engine performance of LPG/Gasoline Bi-Fuel engine. In order to investigate the engine performance during combustion, engine performance are sampled by data acquisition system, for example cylinder pressure, pressure rise rate and heat release rate, while change of the rpm(1500, 2000, 2500) and the ignition timing advance(5°, 10°, 15°, 20°). As the result, between 1500rpm, 2000rpm and 2500rpm, the cylinder pressure and pressure rise rate was increased when the spark ignition was advanced but pressure rise rate at 20° was smaller value.

To improve the drivability and reduce fuel consumption and emissions of an existing sport utility vehicle (SUV), simulation-based vehicle refinement was conducted in this study. A simulation model of the SUV was first established and validated. Both simulation and test results confirm that due to low reserve power both at low and high speed bands, the drivability, fuel economy and emissions of the SUV are unsatisfactory. To refine the vehicle, complex precautions were implemented to upgrade the diesel engine, and the powertrain gear ratios were optimized with a design of experiments (DOE) approach to match the upgraded engine. Updated simulation results demonstrate that the refined vehicle is powerful enough at a sufficient speed range, with moderate fuel consumption at Euro Ⅲ standard emissions. An interim vehicle prototype, with an upgraded engine but an unmatched transmission, was produced; field test results of the interim vehicle proved the effectiveness of the simulation-based SUV refinement. The final, fully refined SUV product is currently in development.

In the development of means of transportation, human beings who walk, ride or ride carriages are now enjoying the benefits of many means of transportation, including bicycles, airplanes, trains, buses, and cars. In the case of automobiles among various means of transportation, there is an advantage that an individual can conveniently move while possessing it. To solve air polution problems at the same time, eco-friendly automobiles such as low-noise, low-pollution, and high-efficiency automobiles have emerged. However, in the case of eco-friendly vehicleJ, engine noise at low speeds is a noise that is unlike existing vehicles and poses a threat to the safety of pedestrians. In this study, virtual engine system has been developed to prevent engine accidents caused by low- The pedestrians are aware of the fact that the vehicle is approaching.

In this note a method of designing optimal vibration control based on Haar functions to control of bounce and pitch vibrations in engine-body vibration structure is presented. Utilizing properties of Haar functions, a computational method to find optimal vibration control for the engine-body system is developed. It is shown that the optimal state trajectories and optimal vibration control are calculated approximately by solving only algebraic equations instead of solving the Riccati differential equation. Simulation results are included to demonstrate the validity and applicability of the technique.