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2기통 소형 터보가솔린엔진에서 배기 밸브 타이밍 제어에 따른 LIVC, EIVC 상태에서의 엔진 효율 영향
장진영,우영민,신영진,고아현,정용진,조종표,김강출,표영덕,한명훈,Jang, Jinyoung,Woo, Youngmin,Shin, Youngjin,Ko, Ahyun,Jung, Yongjin,Cho, Chongpyo,Kim, Gangchul,Pyo, Youngdug,Han, Myunghoon 한국분무공학회 2022 한국액체미립화학회지 Vol.27 No.3
This study examines whether engine fuel efficiency is improved by optimization of the exhaust valve timing in a state where the intake valve timing has been optimized in a small turbo gasoline engine that has intake cams and exhaust cams with fixed valve opening periods. When the exhaust valve is opened late, the expansion stroke is longer, and the efficiency can be improved. A 2-cylinder turbo gasoline engine with 0.8 liters of displacement and an MPI (Multi Point Injection) fuel system was used. The engine was operated at 1,500 and 3,000 rpm, and the load conditions included a partial load of 50 N·m and a high load of 70 N·m. Data was recorded as the exhaust valve timing was controlled, and this was used to calculate the efficiency of combustion using a heat release, the fuel conversion efficiency, and the pumping loss. Results and the hydrocarbon concentrations in the exhaust gas were compared for each condition. Experiment results confirmed that additional fuel efficiency improvements are possible through exhaust valve timing control at 1,500 rpm and 50 N·m. However, in other operating conditions, fuel efficiency improvements could not be obtained through exhaust valve timing control because cases where the pumping loss and fuel/air mixture slip increased when the exhaust valve timing changed and the fuel efficiency declined.
1000MPa급 DP강의 Nd:YAG 레이저 용접부의 기계적 성질과 성형성에 미치는 용접 속도의 영향
장진영,최우남,정병훈,강정윤,Jang, Jin-Young,Choi, Woo-Nam,Jung, Byung-Hun,Kang, Chung-Yun 대한용접접합학회 2009 대한용접·접합학회지 Vol.27 No.2
The effects of welding speed were investigated on penetration characteristics, defects and mechanical properties including formability test in Nd:YAG laser welded 1000MPa grade DP steels. A shielding gas was not used and bead-on-plate welding was performed with various welding speeds at 3.5kW laser power. Defects of surface and inner beads were not observed in all welding speeds. As the welding speed increased, the weld cross-section varied from the trapezoid having wider bottom bead, through X type, finally to V type in partial penetration range of welding speeds. The characteristic of hardness distribution was also investigated. The center of HAZ had maximum hardness, followed by a slight decrease of hardness as approaching to FZ. Significant softening occurred at the HAZ near BM. Regardless of the welding speed, the weld showed approximately the same hardness distribution. In the perpendicular tensile test with respect to the weld direction, all specimens were fractured at the softening zone. In the parallel tensile test to the weld direction, the first crack occurred at weld center and then propagated into the weld. Good formability over 80% was taken for all welding conditions.
장진영(Jinyoung Jang),우영민(Youngmin Woo),이영재(Youngjae Lee),김종남(Jongnam Kim) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
In this research, Ammonia was assessed using ammonia as a fuel for combustion engine. Since ammonia has similar physical property with LPG(liquid petroleum gas), LPG fuel system was plan to use an ammonia fuel system. However, Ammonia-LPG fuel system reactivity resulted in system failure should be checked. For ammonia-LPG fuel system reactivity test, reactor was made and parts of LPG fuel system was assessed. Through the reactor test, O-rings used in parts of fuel injector and tank were corroded. And fuel pump and floater indicating fuel lever were affected. For using LPG fuel system as ammonia fuel system, O-rings should be changed Kaliz O-ring and fuel pump and floater also should be replaced.
FTP-75, WLTC 시험 모드에서 LPG, CNG 자동차의 배출가스 및 PN 비교
장진영(Jinyoung Jang),이영재(Youngjae Lee),권오석(Ohseok Kwon),김정환(Jeonghwan Kim) 한국가스학회 2016 한국가스학회지 Vol.20 No.6
가스연료인 LPG와 CNG는 청정 대체연료로서 차량용 연료로 많이 사용되고 있다. 특히 CNG의 경우 저탄소연료로서 온실가스 배출량 저감에 기여할 수 있다, LPG의 경우 가솔린 차량과 거의 동등한 성능을 가지면서도 연료가격이 저렴하여 택시에 많이 사용되고 있다. 본 연구에서는 동일차량에서 LPG와 CNG를 사용하여 배출가스와 최근 문제가 되고 있는 입자상물질의 배출개수(PN; particle number)에 대하여 비교하였다. 차대동력계를 이용하여 FTP-75와 WLTC 모드에 대하여 시험을 진행하였다. PN은 두 대의 CPC(Condensation Particle Counter)를 이용하여 5 nm 이상과 23 nm 이상의 입자에 대하여 배출 개수를 측정하였다. 배출가스에 있어서는 CO2의 경우 LPG 차량이, 메탄의 경우 CNG 차량이 많이 배출되었다. PN의 경우 두 연료에서 배출되는 PN은 비슷한 수준이었으며, WLTC 에서 고속운전하는 동안 23 nm 이하 크기의 입자 배출 개수가 많았다. Liquefied petroleum gas (LPG) and compressed natural gas (CNG) are often used as fuel for vehicles because they are clean alternative gas fuels. CNG, as a low-carbon fuel, can contribute to the reduction of greenhouse gas emissions. LPG is often used as fuel for taxis because the performance is almost the same as that of gasoline but the price is lower. In the present study, the exhaust gas and the particle number (PN) of particulate matter, which is a recent environmental issue, were compared between LPG and CNG for the same vehicle. A chassis dynamometer was used to conduct the test according to the Federal Test Procedure (FTP)-75 and Worldwide harmonized Light-duty vehicle Test Procedure (WLTC) modes. The PN values of discharged particles having sizes of 5 nm or larger and 23 nm or larger were measured using two condensation particle counters (CPC). The ratio of carbon dioxide was high in the exhaust gas from the LPG vehicle; the ratio of methane was high in the exhaust gas from the CNG vehicle. The PN values of the emitted particles from the two fuels were similar. The PN values of particles having sizes of 23 nm or smaller were high in the high-speed WLTC mode.
스파크 점화 기관에서 밸브오버랩이 잔류가스율 변화에 미치는 영향
장진영(Jinyoung Jang),박용국(Youngkug Park),배충식(Choongsik Bae),김우태(Wootae Kim) 한국자동차공학회 2002 한국 자동차공학회논문집 Vol.10 No.6
Residual gas fraction in an engine cylinder affects engine perfornance, efficiency and emission characteristics. With high residual gas fractions, a flame speed and maximum combustion temperature arc decreased and these are deeply related with combustion stability especially at idle and NOx emission at relatively high engine load.<br/> In this work, the residual gas fraction was calculated by an engine simulation code, which was validated by the experimental data (cylinder pressure and emissions) obtained from 4-eyliner spark ignition engine. A comparison between experimental and computational calculation results was made. The residual gas is generated mostly at low engine speed by the larger pressure difference between the intake and exhaust port. As the valve overlap duration was increased, the amount of residual gas in the cylinder, the amount of HC emission in the exhaust gas and the variation of power output increased.
가솔린, LPG, 디젤 차량에서 윤활유에 따른 배출가스 및 입자상물질
장진영(Jinyoung Jang),이영재(Youngjae Lee),권오석(Ohseok Kwon),우영민(Youngmin Woo),조종표(Chongpyo Cho),김강출(Gangchul Kim),표영덕(Youngdug Pyo),이민섭(Minseob Lee) 한국자동차공학회 2016 한국 자동차공학회논문집 Vol.24 No.2
This study effect of engine oils on regulated fuel economy and emissions including particulate matter (PM) to provide basic data for management of engine oil in vehicles. Three engine oils (Group III base oil, Group III genuine oil with additive package and synthetic oil with poly alpha olefins (PAOs)) were used in one gasoline, one LPG(liquefied petroleum gas) and two diesel vehicles. In the case of diesel vehicles, one is a diesel vehicle without DPF (diesel particulate filter) other is a diesel vehicle with DPF. In this study, the US EPA emission test cycle FTP-75, representing city driving, was used. HORIBA, PIERBURG, and AVL gas analyzers were used to measure the fuel economy and regulated emissions such as CO, NOx, and THC. The number of PM was measured using a PPS (pegasor particle sensor). And, the shape of PMs was analyzed by SEM (scanning electron microscope). The effects of oil type on fuel economy, exhaust gas, and PM were not significant because engine oil consumption by evaporation and combustion in the cylinder is very tiny. Fuel and vehicle type were dominant factors in fuel economy and emissions. HC emission from gasoline vehicles was higher than that from other vehicles and NOx emission from diesel vehicles was higher than that from other vehicles. The number of PM was not affected by the engine oil, but by the driving pattern and fuel. The shapes of the PM, sampled from each vehicle using any test engine oil, were similar.