Electric doors have been applied in urban trains since 2007 and operated for a long time. Recently, the failure of mechanical devices in electric doors have been increasing. The door is a device that is directly related to the safety of passengers. The rivet breakage of a ball/nut assembly may occur to an accident during train operation. In this study, the operating voltage and acceleration data of the door were collected for rivet condition monitoring, and 4 features were extracted in the frequency domain using the acceleration data. The classification performance of the rivet condition according to the axial direction of the acceleration data and 4 kernel functions was evaluated using SVM algorithm. When the X-axis data and Gaussian kernel function were used, the highest classification performance was shown for the electric door’s rivet with 90% accuracy.
Today, conventional CVT equipped vehicle controls engine torque and gear ratio by using engine torque map and shifting map. But this control process is difficult to optimize the fuel economy when the driving mode is changed arbitrary. In this study, I propose the real-time CVT control with considering the power loss of transmission system to improve vehicle fuel economy and drivability. The driving performance and fuel economy of the proposed control logic is analyzed by backward simulation and the validity of new control logic is verified.
Emissions of hazardous substances in automobiles are caused by combustion of internal combustion engines, friction of brake pads and tire wear. In this study, we propose a method to reduce the harmful substances emitted in internal combustion engine by using HHO gas. In order to reduce the exhaust gas of the internal combustion engine, HHO gas having excellent combustion characteristics was added to the combustion chamber. The HHO gas generator was installed in the intake line and the HHO gas was introduced into the combustion chamber with the mixed gas through the intake line. At this time, we compared and analyzed the performance of the engine performance on the presence and absence of HHO gas.
The heat transfer characteristics of a louver fin for a radiator are numerically analyzed to investigate the performance of radiator for automotive. The commercial code FLUENT is utilized to simulate a louver fin to analyze both the flow fields of air and the solid region of lover fin. The numerical analysis is performed with the variation of air mass flow rate. The results show that as mass flow rate increases, louver fin efficiency is nearly constant. The correlation of the average Nu is derived. The results of numerical study is useful in louvered fin design.
The major complaint of hybrid vehicle driver is that real fuel economy is lower than the certified fuel economy. Therefore, it is important to analyze the cause of low fuel economy and to improve the fuel consumption at real driving condition. In this study, the various speed profile is measured by driving urban road with considering different traffic jam. By using backward simulation, the fuel economy characteristics of the acquired driving modes are analyzed. From the simulation results, the operating points of engine and motor analyzed and the cause of decrease of real fuel economy is examined.
The heat transfer characteristics of a spiral type EGR cooler for a diesel engine are numerically analyzed to investigate the performance of EGR cooler. The commercial code FLUENT is utilized to simulate a single spiral tube with constant wall temperature conditions. The numerical analysis is performed with the variation of exhaust gas flow rate. The results show that as mass flow rate increases, temperature difference between inlet and outlet and efficiency become lower, while heat flux gets higher. The empirical correlation is derived in forms of Nusslet number and Reynolds number based on the numerical results.
Because industrial Vehicles drive and work under heavy load condition, the gear ratio of transmission and the stall torque ratio of torque converter is high. Recently, to reduce the cost of vehicle, many people have interest in applying multi-phase torque converter to vehicle and reducing the gear step. In this study, the target performance of vehicle is analyzed and the performance matching of multi-phase torque converter is studied to equip torque converter to heavy duty folk lift vehicle.
The conventional shifting map is developed to enhance the driving performance and fuel economy. According to the driver’s pedaling of accelerator, TCU controls gear ratio in view point of economy or driving performance. In this paper, various reverse engineering is applied to the driving test results of heavy duty AMT vehicle. With the test results, the performance of propulsion source is estimated and basic performance of vehicle is analized. Also the method to derive the shifting schedule according to power or fuel efficient, is developed and compared with the actual shifting map, and various shifting states is estimated. The developed numerical analysis model will be a stepping stone for the shift pattern development and various shift control research
Many countries of the world has been devoting a lot of effort to reduce carbon emission. In order to reduce carbon emission, the high efficiency engine has been studied in the automotive industry. Of these, the spread and research of the diesel engine in Europe center are active. However the combustion characteristic of diesel engines have disadvantages of much NOx and soot emissions. In this study, the optimum regeneration point of the forced regeneration type DPF(Diesel Particulate Filter) that was equipped in medium-duty diesel vehicles using a mechanical fuel injection system have studied. DPF that is applied to the medium-duty diesel vehicle has a bent inlet pipe. The flow distribution characteristics of DPF according to the influence of the bent pipe have investigated. The flow distribution characteristics of DPF according to variation of the engine operating condition is considered to be useful data In order to decide the optimum regeneration point.
The gas flow and heat transfer inside an EGR cooler for a diesel engine are numerically analyzed to investigate the performance of EGR cooler. The commercial code FLUENT is utilized to simulate a single spiral tube with constant wall temperature condition. The numerical analysis is performed with the variation of exhaust gas flow rates according to engine speed. The computational results agree well with the experimental results published before. The results show that the maximum error rate is about 0.6% for all operating conditions. Thus a single tube model with constant wall temperature condition is appropriate for simulating EGR cooler.
This study was analyzed the characteristics of temperature distribution in DPF(Diesel Particulate Filter) equipped with partitioned electric heaters. Analysis parameters was used by variation to the length of pipe from exhaust manifold to inlet of filter. The temperature of the exhaust gas flowing into the DPF is related closely to the regeneration of filter. Due to space constraints, the DPF have inlet of bent pipe. The inlet of bent pipe induce the heterogeneous distribution of flow. The heterogeneous trapping of smoke is induced according to the heterogeneous distribution of flow. And the heterogeneous distribution of temperature in DPF is induced. In this study, without the use of assistive devices for even distribution of flow into DPF, the characteristics of temperature distribution in DPF were investigated according to the variation of the length of inlet pipe.
Hybrid car can improve fuel efficiency using a power of motor that is generated during constant-speed or deceleration driving. The motor is located between engine and transmission. But, when voltage of main battery is low, fuel efficiency is low because the voltage can't run the motor. In this situation, this study observed fuel efficiency when using solar cell for assistance power. In order to verify a fuel consumption of hybrid car equipped solar cell for assistance power, the car was tested downtown driving. As hybrid car was equipped solar cell for assistance, fuel consumption was reduced 8.35 % at running air conditioner. And, at air conditioner doesn't work, fuel consumption was reduced 6.88 %. This point of view, CO2 is expected to reduce in similar proportion.
This study analyzed on the characteristics of temperature distribution in an active regeneration DPF using computer simulation. In order to verify the boundary condition of analysis, results of temperature distribution in DPF are compared between experimental and computer simulation. Using this boundary condition, temperature distribution and filter's durability in DPF analyzed according to various operating conditions. The results of computational analysis are agreed well with experimental ones from the tendency of temperature distribution of axis and radius direction. The temperature increases and the axial temperature gradients in DPF according to velocity of exhaust gas are lowered as the high velocity of exhaust gas. But the temperature gradients of radius direction at exit side in DPF are grown as the high velocity of exhaust gas. The results according to inlet temperature of exhaust gas show that the increase ratios of temperature in DPF are grown as the high temperature of exhaust gas.
Over the past years, many research works have been carried out to investigate the factors which govern the performance of diesel engine. The air pollutant emission from the diesel engine is still a significant environmental concern in many countries. In the present study, new system of smoke reduction of diesel engine is proposed. This new system is using vacuum equipment and STS filter for capture smoke. To confirm new system experiments were performed at engine dynamometer. As a result of this experiment, the smoke reduction ratio of this system was identified high reduction ratio than PDPF. But the power of this system application was measured 10% decrease than base engine performance. There were improvement effects of using STS filter than ceramic filter.
The Dry Continuously Variable Transmission (CVT) consists of a driving pulley and a driven pulley joined by a rubber V-belt. An each pulley consists of a fixed flange and a movable flange. The movable flange of the driving pulley has the centrifugal roller and a ramp plate in the flange. The movable flange moves toward a fixed flange under the actuation of a centrifugal roller, as the driving pulley speed increases. In this study, the function and the relationship of the all parts in the Dry CVT are investigated. The profile of movable flange is analyzed. The effect of axial force is also analyzed by speed ratio and load torque.
This study investigates experimentally Air-fuel ratio feedback control with a fuel valve in a LPG engine. The fueling valve is controlled by electronic control unit which is made with micro computer. Various control logics are employed and then PID control is adopter as a proper logic for own system and Air-fuel ratio feedback control by PID control was experimentally of various operation area with the stable control algorithm of PID control that was earned from the former experiment. On the process the experiment, determination experiment of each control part coefficient was the biggest variable among the whole result of experiment. We could know as a result of experiment that the lange of overshoot is bigger as the proportional control part os bigger integral control part is related with the delay time and coefficient of differential control part is related with the decrease of overshoot range from the experiment of various operation area we could also analyse consequently that direct fuel control in the fuel value makes more stable control status in rare operation and low load area.
우리나라는 기상학적으로 연중 총강수량의 약 2/3가 6~9월에 편중해서 내리고 있고, 지형적으로 국토의 70% 이상이 산지로 구성되어 경사가급해 수해를 입을 가능성이매우 크다. 또한 산업화 및 도시화로인해 불투수층의 증가로 강수량의 대부분이 직접유출로 기여해 강우초기에 노면상의 오염물질을 급속히 하천으로 이동시켜 오염을 가중시키고 있다. 특히 위락시설지역은 도시화에 따른 인구집중으로 지역민들에게 휴식공간 및 공원기능의 제공으로 비점오염원의 이동능력도 증
하도내에서 발생하는 유출량 및 TOC 자료는 비선형성이 강한 자료임에 따라 홍수에 대한 재난대응과 수질의 상시감시를 위해서는 자료의 특성 분석과 예측에 관한 연구는 필수라 할 수 있다. 따라서 본 연구에서 유출량 및 TOC, TOC부하량 자료에 대한 웨이블렛 변환에 의해 최종분해된 최종파형분해단계의 근사성분과 상세성분을 이용하여 예측모형을 개발하였다. 그 결과 기존 인공신경망 모형에서 관찰되었던 시계반대 방향으로 전이되는 지속현상의 극복 가능성을 보여주
인공신경망 이론을 이용하여 강한 비선형성의 경향을 보이고 있는 강우-유출간의 관계를 모형화하기 위한 연구들은 예측뿐만이 아니라 대상자료들의 양상을 분류하여 그 특성을 분석하는 데에도 이용되고 있다. 이와 같은 패턴분류를 위한 SOM(Self-Organizing Map: SOM)의 연구 결과를 검토해보면 SOM 훈련을 위한 지도크기 및 배열의 결정은 SOM 성능에 큰 영향을 미치는 것으로 보고되고 있으나 지도크기 결정시 지도의 종방향 크기와 횡방향 크기를