• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.36-45
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• 2014

Model based control methods are widely used to improve the control performance of diesel engine air systems because the control results of the air system significantly affect the emission level and drivability. However, the model based control algorithm requires a lot of unmeasurable states which are hard to be measured in a mass production engine. In this study, an air system model of the diesel engine is proposed to estimate 11 unmeasurable states using only sensors equipped in a mass production engine. In order to improve the estimation performance in the transient condition, dynamic characteristics of the air system are analyzed and implemented as discrete filters. Turbine and compressor efficiency models are also proposed to overcome a limitation of the constant or look-up table based efficiency values. The proposed air system model was validated in steady state and transient conditions by real-time engine experiments. The maximum error of the estimation for 11 physical states was 11.7%.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.46-49
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• 2001

EMV(electromagnetic valve) 시스템은 자동차에서 기계식 캠을 사용하지 않고 전자기력을 이용하여 흡 배기 밸브를 작동시키고 타이밍을 조절하기 위한 것이다. 본 논문에서는 EMV 시스템을 위한 전자기와 기계적 모델을 사용하여 그에 대한 동역학 모델을 유도하였다. EMV 시스템의 최대 동작주파수가 가솔린엔진의 최대 회전수 6000rpm에 대응한 valve의 주파수가 50Hz 되기 위한 제어기를 설계하였고, 실험을 통하여 문제점들을 파악하고자 한다.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2280-2282
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• 2001

EMV(electromagnetic valve) 시스템은 자동차에서 기계식 캠을 사용하지 않고 전자기력을 이용하여 흡·배기 밸브를 작동시키고 타이밍을 조절하기 위한 것이다. 본 논문에서는 EMV 시스템을 위한 전자기와 기계적 모델을 사용하여 그에 대한 동역학 모델을 유도하였다. EMV 시스템의 최대 동작주파수가 가솔린 엔진의 최대 회전수 6000rpm에 대응한 valve의 주파수가 50Hz 되기 위한 제어기를 설계하였고, 실험을 통하여 문제점들을 파악하고자 한다.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.135-146
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• 2013

This paper presents a feedforward control algorithm for the EGR and VGT systems of passenger car diesel engines. The air-to-fuel ratio and boost pressure are selected as control indicators and the positions of EGR valve and VGT vane are used as control inputs of the EGR and VGT controller. In order to compensate the non-linearity and coupled dynamics of the EGR and VGT systems, we have proposed a non-linear model-based feedforward control algorithm which is obtained from static model inversion approach. It is observed that the average modeling errors of the feedforward algorithm is about 2% using stationary engine experiment data of 225 operating conditions. Using a feedback controller including proportional-integral, the modeling error is compensated. Furthermore, it is validated that the proposed feedforward algorithm generates physically acceptable trajectories of the actuator and successfully tracks the desired values through engine experiments.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.101-101
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• 2012

본 논문은 현재 제품화 단계로 진행 중인 터보 분자펌프(turbo-molecular pump, TMP)와 극저온 펌프(cryopump)의 고장 방지 및 예지 보수를 위한 상태 진단 시스템에 대하여 소개를 한다. 본 상태 진단 시스템은 고진공 펌프들의 다중 상태변수 즉 흡/배기부의 진공 압력, 부위별 온도, 소비 전류(혹은 전력), 그리고 부위별 진동 신호들을 실시간으로 측정하는 상태변수 수집장치, 수집된 시계열 상태변수들이 저장된 database, 그리고 저장된 상태변수를 이용한 고진공펌프의 상태진단 프로그램으로 구성되어 있다. 금번 연구에서 구축한 상태변수 체계의 특징 중 하나는 진동신호를 상태변수로 측정하여 이를 상태진단에 활용하는 점이 기존의 접근방법과 상이한 점이다. 실시간 신호 수집장치는 NI사 PXI 시스템 기반의 16채널 24-bit 동시 전압신호 측정 모듈, 8부위의 온도 측정장치(Lakeshore 218S, RS-232C 통신), 그리고 펌프의 소비전류/전력 측정장치(Hioki 3169, RS-232C), 그리고 고진공 펌프의 흡입 및 배기구의 진공도 측정장치로 구성하였다. 신호 수집용 프로그램은 NI사 Labview를 이용하여 작성하였다. 본 장치는 Nano-Fab 센터의 협조 하에 turbo-molecular 펌프와 cryopump측정 단에 각각 1대를 설치 완료하였으며 현재까지 운용 중이다. PC에 저장된 시계열 상태변수 database는 기 개발된 적응형 인자모델을 이용한 매개변수로 변환되며, 상태진단은 변환된 매개변수를 이용하여 수행할 예정이다.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.6
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• pp.65-73
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• 2008

The purpose of this study is development of universal engine model for integrated Hybrid Electric Vehicle (HEV) simulator and a optimization of engine model. The engine model of this study is based on the MATLAB Simulink for universal and include engine fuel economy technologies for HEV. Various engine fuel economy technologies for HEV is estimated by commercial engine 1-D simulation program - WAVE. And, the 1-D simulation model of base version is compared with engine experiment result. The analyzed engine technologies with 1-D simulation are Dual-CVVT, Atkinson-Cycle and Cylinder-Deactivation System. There are improvement of fuel economy and power performance with Dual-CVVT model at part load and full load, pumping loss reduction with Cylinder-Deactivation System at idle and regeneration. Each estimated technologies are analyzed by 1-D simulation on all operation region for base data to converse simulink. The simulink based engine model maintains a signal with ECU for determination of engine operation point.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.6
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• pp.615-622
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• 2010

In this study, a 0D multizone spray-combustion model is developed for the estimation of the performance and NOx emission of medium-sized direct-injection marine diesel engine. The developed combustion model is coupled with the commercial 1D cycle-simulation model, Boost, to analyze the entire engine system, including the intake and exhaust. The combustion model code was generated using Fortran90, and the model was coupled with Boost by connecting the generated code to a user-defined high-pressure cycle (UDHPC) interface. Simulation was performed for two injectors (8 holes and 10 holes) and two engine loads (50% and 100%), and the results of simulation were in good agreement with engine performance test.