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김득상,조용석 대한기계학회 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.11
Results from an experimental study of flow distribution in a close-coupled catalytic converter (CCC) are presented. The experiments were carried out with a flow measurement system specially designed for this study under steady and transient flow conditions. A pitot tube was a tool for measuring flow distribution at the exit of the first monolith. The flow distribution of the CCC was also measured by LDV system and flow visualization. Results from numerical analysis are also presented. Experimental results showed that the flow uniformity index decreases as flow Reynolds number increases. In steady flow conditions, the flow through each exhaust pipe made some flow concentrations on a specific region of the CCC inlet. The transient test results showed that the flow through each exhaust pipe in the engine firing order, interacted with each other to ensure that the flow distribution was uniform. The results of numerical analysis were qualitatively accepted with experimental results. They supported and helped explain the flow in the entry region of CCC.
김득상,조용석 한국자동차공학회 2005 International journal of automotive technology Vol.6 No.6
The effects of spark timing and exhaust valve timing change on exhaust gas temperature during cold start period of an SI engine are studied through engine bench tests. The exhaust gas temperature increases when the spark timing or valve timing are retarded individually, due to late combustion or slow flame speed. Therefore, exhaust gas temperature shows a large increase when the two timings are retarded simultaneously. However, it is considered that combustion stability during cold start deteriorated under these retarded conditions. To increase exhaust gas temperature for fast warmup of catalysts while maintaining combustion stability, an optimal condition for spark and valve timing retard should be applied for the cold start period.
[가솔린엔진부문] 미연 배기가스 점화 제어기술을 이용한 배기저감
김득상(Duksang Kim),강봉균(Bonggyun Kang),김성철(Sungchul Kim),이상진(Sangjin Lee),양창석(Changsuck Yang),조용석(Yongseok Cho) 한국자동차공학회 2001 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2001 No.11_1
UEGI (Unburned Exhaust Gas Ignition) is expected to help faster warm up of a close-coupled catalytic convener (CCC) by igniting the unburned exhaust mixture using two glow plugs installed in the upstream of the catalyst. In this study, a control module and an algorithm for the UEGI technology was developed. It changes I/O signals from the ECU, and controls ignition signals, glow plug on/off signals, and cooling water temperature signals to modify AIF ratios during cold start of the test engine. The control module is also designed to be readily applicable to a conventional vehicle, therefore, its repeatability, stability of UEGI flame, precision of light-off time and performance characteristics were tested and analyzed on an engine test bench. In addition, both the UEGI system and a hydrocarbon adsorber were applied to the exhaust system for more effective reduction of HC emission during the cold start period. Experimental results show that the CCC reaches the light-off temperature faster compared with the Baseline exhaust system, and HC and CO emissions are reduced significantly during the cold star1. The UEG I control module proved its effectiveness in precise control of the UEGI system.<br/> <br/> <br/> <br/> - 74p<br/> <br/> <br/> <br/> This paper proposes a method to detect the misfired cylinder using Exhaust Pressure Ascent Rate.<br/> If a misfire occurs, the engine will be lost some power and consumes the more fuel and the torque will be unsteady. Most of all, the misfire affects a bad influence of the 3-way catalyst and emits unburned hydrocarbon in the air.<br/> To prevent these unusual phenomena and eliminate the factor of the environmental pollution. It is an important thing to detect the misfired cylindere.<br/> Experimental results showed that the method using the exhaust pressure ascent rate is proven to be effective in the detection of misfired cylinder on gasoline engine regardless loads and revolutions of the engine