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승용 디젤 엔진의 실린더 차이 압력을 이용한 IMEP 추정 및 제어 알고리즘 개발
정재성(Jaesung Chung),오승석(Seungsuk Oh),박인석(Jaesung Chung),선우명호(Myoungho Sunwoo) 대한기계학회 2012 大韓機械學會論文集B Vol.36 No.9
이 연구에서는 실린더 압력과 모터링 압력의 차이인 차이 압력(difference pressure)을 이용하여 IMEP 를 추정하는 방법을 제안하고, 추정된 IMEP 를 IMEPdiff 로 정의하였다. IMEPdiff 는 차이 압력이 연소 시작 시점에서 연소 종료 시점까지만 존재하는 압력이라는 사실에 기반하여 이론적인 IMEP 계산식의 연산 구간을 최적화한 것으로 IMEP 와 비교 시 R<SUP>2</SUP> 0.9955 의 높은 선형관계를 보였다. 또한 이론적인 IMEP 계산 방법과 비교하여 21 %의 실린더 압력 데이터 및 31 %의 계산량만으로 IMEP 획득이 가능하여 실시간 제어에 용이하다. IMEPdiff 추정 및 제어 성능은 엔진 실험을 통하여 검증하였으며, IMEPdiff 제어를 통하여 실린더 간 토크 편차 감소를 확인하였다. In this study, we propose a new method for estimating the IMEP using difference pressure, which is the pressure difference between the cylinder pressure and the motoring pressure. The estimated IMEP, denoted as IMEPdiff, optimizes the theoretical IMEP calculation range based on the fact that the difference pressure exists between the start and the end of combustion. IMEPdiff is verified to have a high linear correlation with IMEP with R<SUP>2</SUP> of 0.9955. The proposed method can estimate the IMEP with 21% of the cylinder pressure data and 31% of the calculation effort compared to the theoretical IMEP calculation method, and therefore, it has great potential for realtime implementations. The estimation and control performance of IMEPdiff is validated by engine experiments, and by controlling IMEP<SUP>diff</SUP>, the torque variation between the cylinders was reduced.
디젤 엔진의 엔진 토크 제어를 위한 실시간 IMEP 추정 알고리즘 개발
정재성(Jaesung Chung),오승석(Seungsuk Oh),이민광(Minkwang Lee),선우명호(Myoungho Sunwoo) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
The indicated mean effective pressure (IMEP) is an indicator which represents the engine torque directly from the in-cylinder pressure. However, the calculation of IMEP requires a large number of cylinder pressure data acquisition and long computation time. For this reason, an estimation method of IMEP with less number of cylinder pressure data acquisition and computation time is needed for real-time combustion control. In this study, we proposed the IMEP estimation algorithm using difference pressure. The difference pressure data during the expansion stroke is used to estimate the IMEP and defined the estimated IMEP value as IMEP<SUB>diff</SUB>. The proposed IMEP<SUB>diff</SUB> has high linear relationship with the real IMEP regardless of different engine operating conditions. Furthermore, the IMEP<SUB>diff</SUB> method reduces the data acquisition of cylinder pressure by 75% and the computational load by 62% compared to the IMEP method which gives a great potential for the real-time estimation of IMEP.
김도화(Dohwa Kim),오병걸(Byoungul Oh),오승석(Seungsuk Ok),이강윤(Kangyoon Lee),선우명호(Myoungho Sunwoo) 한국자동차공학회 2009 한국 자동차공학회논문집 Vol.17 No.2
Calculation of indicated mean effective pressure(IMEP) requires high cylinder pressure sampling rate and heavy computational load. Because of that, it is difficult to implement in a conventional electronic control unit. In this paper, a cylinder pressure based real-time IMEP estimation method is proposed for controller implementation. Crank angle at 10-bar difference pressure(CA<SUB>DP10</SUB>) and cylinder pressure difference between 60° ATDC and 60° BTDC(DP<SUB>deg</SUB>) are used for IMEP estimation. These pressure variables can represent effectively start of combustion(SOC) and fuel injection quantity respectively. The proposed IMEP estimation method is validated by transient engine operation using a common-rail direct injection diesel engine.
가솔린 직접분사엔진에서 EGR량에 따른 연비향상에 관한 연구
백동훈,이수룡 한국기계기술학회 2018 한국기계기술학회지 Vol.20 No.1
The effect of EGR on fuel economy was investigated in a gasoline direct injection engine. The 1-D cycle simulation program of GT-Power was utilized to evaluate fuel consumption rate. At high load, fuel consumption increased by about 2~6% according to EGR rate. Knock mitigation was the main effects, gaining about 80% of the total fuel consumption improvement. At low load, fuel consumption reduction was 0.6~2%, which was much lower than that for high load. The lower improvement of fuel consumption at low load is attributed to solely dilution and chemical effects of exhaust gas.
디젤엔진에서 분사조건이 연소 및 배기 특성에 미치는 영향 예측
류봉우(Bong Woo Ryu),김형준(Hyung Jun Kim),이제형(Je-Hyung Lee),이창식(Chang Sik Lee) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This study numerically investigated the combustion and emission characteristics in accordance with single and split injection conditions. Numerical analysis was performed by using the AVL-FIRE code with the ECFM-3Z combustion model. In-cylinder pressure profiles of calculation results had good agreement with experimental results. In case of early injection (40° BTDC), the combustion and emission characteristics of single injection were deteriorated due to the occurrence of the wall wetting at both the piston head and cylinder liner. However the split injection led to lower the amount of wall wetting and increase the combustion pressure and indicated mean effective pressure (IMEP) through the wide distribution of air-fuel mixture in the cylinder.