• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.370-373
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• 2005

In this research, we presented the regenerative braking algorithms considering fuel economy and charging oftenness, and also analyzed these algorithms. The first algorithm was the regenerative braking algorithm for the ideal recovery of kinetic energy. The HEV using this algorithm had high fuel economy, on the other hand frequent charging was occurred. The second algorithm was the regenerative braking algorithm for reduction of the charging oftenness. Using this algorithm, the HEV had the low charging oftenness and small loss of fuel economy.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.861-864
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• 2005

Brake noise has been one of the most difficult concerns in the automotive industry. Although substantial research has been conducted to predict and eliminate brake noise, there is yet no method to completely suppress brake noise. Furthermore, little effort has been made to improve noise and vibration characteristics of the railway brake system. The amount of sound energy radiated from the railway brake system is much larger than that from the automobile, and it causes discomfort of passengers in the station. In this paper, noise and vibration caused by the braking force of the KTX vehicle have been measured and analysed. Results show that noise level increases abruptly right before a train comes to a complete stop. Furthermore, typical characteristics of the disk brake squeal have been observed.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.7
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• pp.123-130
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• 1995

This study presents model synthesis and performance investigation of a new brake system using electro-rheological(ER) fluids. Field-dependent Bingham properties characterized by non-zero yield stresses of the ER fluids are experimentally distilled. These properties are then incorporated with the governing equation of the proposed brake system which features design simplicity, fast response and salient controllability. After analyzing system performance with respect to design parameters such as electrode gap and length, an appropriate size of the brake is designed and fabricated. Both simulation and experimental works are undertaken in order to determine the feasibility and efficiency of the proposed brake system. The system performances are justified by evaluating field-dependent braking torques as well as braking times.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.11
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• pp.65-74
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• 2002

This paper examines the usefulness of a Brake Steer System (BSS), which uses differential brake forces for steering intervention in the context of Intelligent Transportation Systems (ITS). In order to help the car to turn, a yaw moment can be achieved by altering the left/right and front/rear brake distribution. This resulting yaw moment on the vehicle affects lateral position thereby providing a limited steering function. The steering function achieved through BSS can then be used to control lateral position in an unintended road departure system. A 8-DOF nonlinear vehicle model including STI tire model will be validated using the equations of motion of the vehicle. Then a controller will be developed. This controller, which will be a PID controller tuned by Ziegler-Nichols, will be designed to explore BSS feasibility by modifying the brake distribution through the control of the yaw rate of the vehicle.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.114-116
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• 2009

최근 계속되는 유가 상승과 화석에너지의 고갈 문제, 그리고 환경에 대한 관심 증가로 인해 자동차의 연비 개선 및 배기가스 저감을 위한 친환경 저연비 자동차 기술이 요구되고 있다. 이들 중 하이브리드 차량은 화학적 에너지 저장 장치에 차량 감속 시 회생 제동을 통해 전기 에너지를 저장하고 가속 시 이 에너지를 다시 사용함으로써 연비 개선과 배기가스 저감 효과를 가져 올 수 있다. 이를 위하여 회생 제동 시에 발생하는 에너지를 저장하기 위해 배터리 또는 초고용량 커패시터가 사용 된다. 본 논문에서는 두 에너지 저장 장치의 특성을 전기적인 등가회로 모델로 표현하고 주파수 응답을 통해 온도와 SOC에 따른 각각의 회로 정수를 산출할 뿐 아니라 이 때 주파수 변화에 따른 전압과 전류의 위상차와 역률에 관하여 알아보고자한다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1154_1155
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• 2009

본 논문은 철도부하의 이동을 고려한 전력조류계산 알고리즘에 기반하여, 에너지 저장장치를 설치하였을 때 철도계통의 영향 해석에 관한 논문이다. 철도부하는 위치적 변화 뿐 만 아니라 기동-타행-제동의 운전모드의 변화에 따라 전력소비 패턴이 달라지는데, 제동 시에 발생하는 회생에너지를 에너지 저장장치를 이용하여 활용함으로서 에너지 절감 효과 및 가선전압 안정화를 구현할 수 있다. 본 논문에서는 서울지하철 2호선의 실계통에 대한 사례연구를 수행하여, 실계통에 에너지 저장장치를 적용함으로서 그 필요성을 증명하였다.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.29-38
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• 1997

In this paper, brake steering performance of electric-driven special-purpose vehicles is investigated. A 14 DOF model is developed considering nonlinear character- istics of the suspension and tire. Based on the model, cornering performance is analyzed for brake steering, acceleration steering and pivoting, respectively. Simulation results are obtained based on the developed SIMULINK module. This analysis about the non steady state cornering performance is particularly important for armored vehicles because the projected route of the vehicle at emergency should be predicted accuracy.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.7
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• pp.86-93
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• 1999

Turbocharger has been used to increase the performance of diesel engine, especially ship engine , for years. Recently, the turbocharger is being adopted not only for an agricultural engine but also for an automobile engine. To improve the performance of diesel engine , the problem of the reduction of A/F ratio in high speed should be solved. Turbocharger is well known for its cost effectiveness, reliability and duration . In this study, an experiment was conducted to verify simulation program . The results for natural aspiration engine and turbocharged engine were compared. In order to estimate the characteristics of exhaust gas, D-13 mode was selected. Power, torque and BSFC of turbocharged engine were increased than those of natural aspiration engine by about 48%, 46% and 5%, respectively . The components in exhaust gas except NOx from turbocharger engine were less than the amount set up for 2000-year regulation.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.5
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• pp.119-126
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• 2003

The simulator of a vehicle equipped with hydrostatic transmission and hydraulic accumulator type-braking energy regeneration system is developed using a PC. The simulator receives the accelerator pedal angle and the brake pedal angle generated by the operator using the keyboard, updates the state variables of the energy regeneration system responding to the input signals, and draws the moving pictures of the accumulator piston, pump plate angle and pump/motor plate angle every drawing time on the PC monitor. Also, the operator can observe the accel pedal angle, brake pedal angle, pressures of accumulators, vehicle speed, hydraulic torque, engine torque and air brake torque representing the operation of braking energy regeneration system through the PC monitor every drawing time. The simulator can be a very useful tool to design and improve the braking energy regeneration system.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.2
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• pp.117-123
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• 1994

This paper describes the effect of air assisted fuel injection system(AAI) using compressed air to improve the performance of lean combustion engine. AAI is designed to promote fuel atomization and intake flow. In order to investigate the performance of engine with AAl, experiments are conducted varying the engine revolution speed, lean air-fuel ratio and intake manifold pressure. Compared with the original engine, the performance of the engine with MI is improved as the air-fuel mixture becomes leaner or the engine load becomes lower. The descreasing rate of BSFC is propotional to the relative air-fuel ratio and the lean misfire limit extended more than 0.2 relative airfuel ratio.