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승용자동차 소비자 운전특성 분석을 통한 출발가속성능 개선 방안 고찰
정필기(Philki Jung),지선호(Sunho Ji),박정률(Jungryul Park) 한국자동차공학회 2016 한국자동차공학회 학술대회 및 전시회 Vol.2016 No.11
There are many restrictions on the developing vehicle acceleration performance due to the fuel consumption and the ever more stringent regulation of emissions. As the fuel economy and the emission become more important, the car makers tend to neglect the acceleration performance on a part load. As a result, some customers driving small and compact passenger car complain about the engine lacks power during launch, especially on the city road with all stop and go traffic. So, this paper discusses the first step in the customer’s complaints of acceleration performance and more specifically analyze customer’s driving pattern related to the launch performance on the real road. In order to do this test on the real road, the specific test course that represent the heavy city traffic with its delays at lights and crosswalks of Korea has been established within a relatively short distance on the public road and the required data for this study was obtained on a several vehicles driven by some customers under variable traffic conditions. And, the simple statistical method, T-test and F-test, have been used to analyze the correlation between each factors like an acceleration pedal position, pedal tip-in rate and acceleration by gender, age and vehicle. Ultimately this study focused on the analysis of the customer’s driving behavior of an acceleration pedal operation correlated to the acceleration performance to find the base guideline of launch performance. It is hoped to provide guidelines to direct performance development for improving launch performance.
김정석(Jeongseok Kim),지선호(Sunho Ji),박정률(Jungryul Park) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
This paper presents the modeling of a variable intake manifold (VIM) based on a linear parameter-varying (LPV) model approach which takes into account model parameter variation with the operation point. The rate of change of volume and the actuator dynamics of the VIM are first added, and then reformulated in an LPV form. The selection of scheduling variables and the parameter dependence of the LPV model are also discussed. This approach generates the LPV model critical for air charge estimation design which helps to reduce the calibration effort. The effectiveness of the proposed approach is assessed by numerical simulation results.
김정석(Jeongseok Kim),지선호(Sunho Ji),박정률(Jungryul Park) 한국자동차공학회 2015 한국자동차공학회 학술대회 및 전시회 Vol.2015 No.11
High model fidelity to transient responses of internal combustion engines is a critical factor in applying model-based calibration methodologies, which allows useful environments and capabilities for engine controller development process in the automotive industry. White-box identification from establishing governing equations of physical laws is commonly used for hardware-in-the-loop simulations. Finding coefficients of governing equations, however, accompanies additional experiments, and hidden dynamics deteriorate the accuracy of transient responses. This paper present the application of nonlinear identification techniques to develop engine models from vehicle driving data. A nonlinear autoregressive model, a linear parameter varying model, and a local network model are used and compared to discuss the validity of data-driven engine modeling with respect to engine controller development process.
파워트레인 HiL 환경을 위한 비선형 시스템 규명 접근법
김정석(Jeongseok Kim),지선호(Sunho Ji),박정률(Jungryul Park) 한국자동차공학회 2013 한국자동차공학회 학술대회 및 전시회 Vol.2013 No.11
Hardware-in-the-Loop simulation allows useful environments and capabilities for controller development process in the automotive industry. It has been extensively used in the software validation of embedded powertrain control systems, and shows growing potential for the model-based calibration of engine management systems. To meet their requirements, a proper powertrain model is critical. This paper presents the application of nonlinear experimental identification which gives the powertrain model having good model fidelity and suitable for real-time computation. Nonlinear identification techniques are applied to building the intake manifold model of a gasoline engine with variable valve timing and the vacuum actuator system of a diesel engine with variable geometry turbo charger. Experimental driving data are used as inputs to identify them, and the outputs of the identified model are compared with the corresponding outputs of the experimental vehicle. The validity of nonlinear identification for powertrain HiL environment is discussed with respect to the powertrain development phase.
Hardware-in-the-Loop Simulator를 위한 파워트레인 모델 검증 프로세스
김정석(Jeongseok Kim),지선호(Sunho Ji),박정률(Jungryul Park) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
Hardware-in-the-Loop simulation allows useful environments and capabilities for controller development process in the automotive industry. It has been extensively used in the software validation of embedded powertrain control systems, and shows growing potential for the model-based calibration of engine management systems. To meet their requirements, a proper powertrain model is critical. This paper presents the model validation process which gives the powertrain model having good model fidelity and suitable for real-time computation. Theoretical modeling and experimental identification are discussed with respect to the development phase, the design of experiments, and the use of advanced simulation tools. Data from driving cycles are used as inputs to identify the air-path model of a gasoline engine, and the outputs of the identified model are compared with the corresponding outputs of the experimental vehicle.
2차 공기 분사 위치에 따른 촉매 내 공급 공기 분포에 대한 전산 유동해석
윤정의(Jeong-Eui Yun),김성훈(Sunghoon Kim),지선호(Sunho Ji) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4
SAI(Secondary Air Injection) system has been studied widely as one of the promising countermeasure for reducing HC emission at cold start. In this paper, in order to find out the optimal position of SAI, computational thermal fluid analysis on exhaust system adapted SAI system is performed using commercial 3-D CFD code, CFX. The present results showed that SAI position strongly affected the uniformity of air distribution in front of catalyst. And also through the decision process of optimal position of SAI, new index, uniformity of air distribution(U<SUB>φ</SUB>) is proposed to define it quantitively. Because U<SUB>φ</SUB> is very simple equation and similar with flow uniformity, it is very easy to figure out the physical meaning and to apply it to practices.
HiL 시뮬레이터를 이용한 디젤엔진 VGT 공압 구동기 OBD 소프트웨어의 강건성 평가
김정석(Jeongseok Kim),윤원석(Wonseok Youn),지선호(Sunho Ji),박정률(Jungryul Park) 한국자동차공학회 2014 한국자동차공학회 부문종합 학술대회 Vol.2014 No.5
On-board diagnostic (OBD) strategies for vehicle embedded controllers are critical to meet environmental and safety requirements. The software and calibration that can realize the intended OBD strategies should be robust to noise factors involving machining tolerance and aging of system components. Hardware-in-the-Loop simulation gives useful environments for evaluating the robustness of them, which is largely due to the easiness of generating noise models. This paper presents the robust assessment of OBD software for a VGT pneumatic actuator in diesel engines. Orthogonal array tests are employed for OBD software validation from a Design for Six Sigma (DFSS) perspective. This DFSS approach shows the opportunity of assessing the robustness with quantitative and objective index.
박민철(Minchul Park),김정호(Jungho Kim),지선호(Sunho Ji),박정률(Jungryul Park) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
The trend of exhaust emission regulation requires SULEV which is more stringent compared to ULEV. LPGi (LPG gaseous injection) system vehicle has been commercialized, but is required to an improved system adequate to SULEV regulation. Acknowledged methods of Exhaust After Treatment system are EHC(Electrically Heated Catalyst), Spark Retard Control and SAI(Secondary Air Injection) which has been known as a method of reducing Catalyst light-off time. The focus of this paper is to reduce HC(Hydro-Carbon) & NOx(Nitrogen Oxide) using fuel control with current LPGi system. In theory, the thermal efficiency & the vaporization performance of LPG fuel is better than gasoline fuel. And additionally, there is no wall wetting on LPGi system because the vaporized fuel is injected into cylinder directly. So in case of LPGi system, it is possible to control the exact fuel mass from cold start. Thus LPGi system can reduce much of the exhausted HC before catalytic converter is activated. The purpose of this paper is to reduce HC & NOx in cold engine operation area of CVS-75 test mode and to review the possibility of meeting SULEV emission regulation although its system has a certain level of disadvantage regarding known mismatch of air delivery to exact exhaust engine stroke. Another purpose of this paper is to review effects to HC & NOx reduction per Air/Fuel ratio change.
냉 시동 개선을 위해 2차 공기 공급 시스템을 채택한 촉매 변환기내배기가스 해석
윤정의(Jeong-Eui Yun),김성훈(Sunghoon Kim),지선호(Sunho Ji) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
In this paper, emission analysis during cold start period of CVS-75 mode in LPG vehicle was performed to find out proper operating conditions of SAI(Secondary Air Injection) system. In order to meet SULEV target, the simulated emission system had a SAI system as well as a MCC(Manifold Catalytic Converter) and a UCC(Under body Catalytic Converter). Using commercial 1-D code AMESIM, in which 7 step global surface chemical reactions of Langmuir-Hinshelwood type were adopted, transient emission analysis in the exhaust system during cold start period of CVS-75 mode were carried out to figure out the effects of flow rate, duration of supply air on HC, CO, NO emission.