• Title, Summary, Keyword: Exhaust emissions

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A Study on Idle Performance Improvements for a Gasoline Engine with the Syngas Assist (합성가스를 이용한 가솔린엔진 아이들 성능 개선에 관한 연구)

  • Song, Chun-Sub;Kim, Chang-Gi;Kang, Kern-Young;Cho, Young-Seok
    • 한국연소학회:학술대회논문집
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    • pp.245-251
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    • 2005
  • Recently, fuel reforming technology for the fuel cell vehicle has been applied to internal combustion engines, with various purpose. Syngas which is reformed from fossil fuel has hydrogen as a major component. It has better effort in combustion characteristics such as wide flammability and hig speed flame propagation. In this study, syngas was added to a gasoline engine for the improvement of combustion stability and exhaust emission in idle state. Combustion stability, exhaust emissions, fuel consumption and exhaust gas temperature were measured to investigate the effects of syngas addition on idle performance. Results showed that syngas has ability to extend lean operation limit and ignition retard range. with dramatical reduction of engine out emissions.

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Combustion and Exhaust Emission Characteristics of Bio-Ethanol Fuel(E100) in SI Engine (SI 엔진에서 바이오에탄올 연료(E100)의 연소 및 배기특성)

  • Ha, Sung-Yong;Lee, Chang-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.8
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    • pp.582-588
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    • 2008
  • An experimental investigation was conducted to investigate the effect of Bio-ethanol fuel on the engine performance and exhaust emission characteristics under various engine operating conditions. To investigate the effect of bio-ethanol fuel, the commercial 1.6L SI engine equipped with 4 cylinder was tested on EC dynamometer. The engine performance including brake torque, brake specific fuel consumption, and barke specific energy consumption of bio-ethanol fuel was compared to those obtained by pure gasoline. Furthermore, the exhaust emissions were analyzed in terms of regulated exhaust emissions such as unburned hydrocarbon, oxides of nitrogen, and carbon monoxide.Result of this work shows that the effect of blending of ethanol to gasoline caused drastic decrease of emissions under various operating conditions. Also, improved engine performance such as brake torque and brake power were indicated for bio-ethanol fuel.

A Study on the Effects of Recirculated Exhaust Gas on Soot Emissions in Diesel Engines (디젤기관 매연 배출물에 미치는 재순환 배기의 영향에 관한 연구)

  • Bae, M.W.;Lim, J.K.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.6
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    • pp.142-154
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    • 1998
  • The effects of recirculated exhaust gas on the characteristic of soot emissions have been investigated by using an eight-cylinder, four-stroke, direct injection and water-cooled diesel engine operating at several loads and speeds. The experiments in this study are carried out at the fixed fuel injection timing of $38^{\circ}$ BTDC regardless of experimental conditions. The intake oxygen concentration and the mean equivalence ratio calculated by the intake air flow and fuel consumption rate are used to analyze and discuss the influences of EGR rate on soot emissions. Results of this study indicate that soot emissions increase owing to the drop of intake oxygen concentration and the rise of equivalence ratio as the EGR rate increases at a given engine load and speed, especially the high load.

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The Effects of Fuel Injection Skips on the Reduction of Harmful Exhaust Gases during an SI Engine Starting (가솔린 기관의 시동시 연료분사스킵이 유해배출가스 저감에 미치는 영향)

  • Kim, S.S.
    • Journal of Power System Engineering
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    • v.10 no.1
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    • pp.5-11
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    • 2006
  • During the SI engine starting up, starting conditions directly contribute to the harmful emissions in spark ignition engines. The effects of catalyst temperatures and fuel injection skip methods on HC emissions were investigated. The test was conducted on a 1.5L, 4-cylinder, 16 valve, multipoint-port-fuel-injection gasoline engine. To understand the formation of HC emissions, HC concentration was measured in an exhaust port using a Fast Response Flame Ionization Detector(FRFID). The result showed that HC emissions, which were generated during initial stage of the starting, could be reduced by coolant temperature and fuel injection skips. And through the vehicle test of ECE15+EUDC, it is convinced that the optimized fuel injection skip method according to coolant temperatures have favourable effects on the reduction of harmful exhaust emissions including HC during the SI engine start.

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Effects of Suction Air Humidity on the Combustion and Exhaust Emissions Characteristics in Diesel Engine (디젤기관에 있어서 흡기습도 변화가 연소 특성과 배기배출물 특성에 미치는 영향)

  • 임재근;김동호
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.4
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    • pp.421-426
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    • 2000
  • A study on the combustion and exhaust emissions characteristics of diesel engine with various suction air humidity is performed experimentally. In this paper, suction air humidity is changed from RH 50% to RH 90%, the experiments are performed at engine speed 1800rpm, and main measured parameters are cylinder pressure, fuel consumption rate, CO, HC, NOx and Soot emissions etc. Increase of suction air humidity from RH 50% to RH 90% does not effect specific fuel consumption, decreases maximum pressure in cylinder, ratio of maximum pressure rise and net heat release, and delays ignition timing. Also, that increases CO and HC emissions, decreases NOx emissions, but does not constant in changing tendency on emission.

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Multidimensional Engine Modeling: NO and Soot Emissions in a Diesel Engine with Exhaust Gas Recirculation

  • Kim, Hongsuk;Nakwon Sung
    • Journal of Mechanical Science and Technology
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    • v.15 no.8
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    • pp.1196-1204
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    • 2001
  • The effects of EGR(Exhaust Gas Recirculation) on heavy-duty diesel engine performance, NO and soot emissions were numerically investigated using the modified KIVA-3V code. For the fuel spray, the atomization model based on the linear stability analysis and spray wall impingement model were developed for the KIVA-3V code. The Zeldovich mechanism for the formation of nitric oxide and the soot model suggested by Hiroyasu et al. were used to predict the diesel emissions. In this paper, the computational results of fuel spray, cylinder pressure, and emissions were compared with experimental data, and the optimum EGR rates were sought from the NO and soot emissions trade-off. The results showed that the EGR is effective in suppressing NO but the soot emission was increased considerably by EGR. Using cooled EGR, soot emission could be enhanced without worsening of NO.

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Cycle Resolved NO Emissions and Its Relation with Combustion Chamber Pressure in an S.I. Engine with Fast Response NO Analyzer

  • Sung, Jung-Min;Kim, Hyun-Woo;Lee, Kyung-Hwan
    • Journal of Mechanical Science and Technology
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    • v.17 no.10
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    • pp.1563-1571
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    • 2003
  • A fast response NO analyzer was applied to investigate the relation between cycle-by-cycle NO emissions and combustion chamber pressure. NO emissions were sampled at an isolated exhaust manifold of 4-stroke spark ignition engine to avoid the interference of exhaust gas from other cylinders. The linear correlation analysis was performed with collected data of NO emissions and combustion chamber pressure with respect to the various air-fuel mixture ratios and engine loads. The sampled data sets were obtained during 200 cycles at each operating condition. The results showed that there was a typical pattern in NO emissions from an exhaust port through a cycle. It was possible to set a block of crank angle in which the linear correlation coefficient between NO emissions and combustion chamber pressure was high. As the engine load increased, NO emissions were more dependent on combustion chamber pressure after TDC. It was also analyzed that the correlation between two parameters with respect to air-fuel mixture ratio tended to increase as mixture went leaner. Furthermore, this correlation coefficient for the mixture near the lean limit seemed to be kept high even though combustion was unstable.

Fast Light-Off of Catalyst using Cranking Exhaust Gas Ignition (시동 배기가스 점화기술을 이용한 촉매의 예열시간 단축)

  • 조용석;엄인용;이윤석;김득상;김충식;천준영;최진욱
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.2
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    • pp.43-49
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    • 2001
  • In order to satisfy the ULEV emissions regulation, fast light-off of a catalyst is essential for reduction of HC and CO emissions during the cold start. Cranking Exhaust Gas Ignition(CEGI) method developed in this study showed that the catalyst reaches the light-off temperature in a few seconds. The CEGI stops the ignition signal for a few seconds during the cranking period, so the unburned fuel-air mixture bypasses the combustion chamber and flows through the exhaust manifold. When the unburned mixture reaches two glow plugs installed upstream of the catalyst, it burns and releases the thermal energy to heat up the catalyst, In the FTP-75 vehicle tests, the CEGI showed that the exhaust emissions reduced by 47.7% for THC and by 88.6% for CO in the cold-transient phase of the test.

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The Effect of an Aromatic Content on Exhaust Emissions in Low Temperature Diesel Combustion (저온 디젤 연소에서 연료의 방향족 성분이 배기가스에 미치는 영향)

  • Han, Man-Bae
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.3
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    • pp.106-112
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    • 2011
  • This study is to investigate the effect of an aromatic content in high cetane number (CN) fuels on exhaust emissions under low temperature diesel combustion, which expands the previous research about an aromatic content in low CN fuels. A 1.9L common rail direct injection diesel engine was run at 1500 rpm 2.6 bar BMEP with four fuel sets: an aromatic content of 20% (A20) or 45% (A45) with CN30, i.e. low CN fuels, and CN55, i.e. high CN fuels. Given experimental conditions, the trend of exhaust emissions in high CN fuels was inconsistent with that of low CN fuels which all produced nearly zero smoke but higher NOx for the high aromatic fuel (CN30-A45). For high CN fuels, however, the low aromatic fuel (CN55-A20) produced lower smoke than the high one (CN55-A45) while NOx was similar to each other. The cause of this discrepancy between high CN and low CN fuels is unclear whether it comes from that CN may be a dominant factor to govern exhaust emissions rather than an aromatic content or that the actual CN value of CN55-A45 is lower than CN55-A20. More decent fuel matrix should be prepared and further experiments are needed to confirm it.

The Effect of T90 Temperature on Exhaust Emissions in Low-temperature Diesel Combustion (저온 디젤 연소에서 T90 온도가 배기가스에 미치는 영향)

  • Han, Man-Bae
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.4
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    • pp.72-77
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    • 2011
  • This study is to investigate the effect of the distillation temperature in ultra low sulfur diesel fuel on exhaust emissions in the low-temperature diesel combustion with 1.9L common rail direct injection diesel engine. Low temperature diesel combustion was achieved by adopting an external high EGR rate with a strategic injection control. The engine was operated at 1500 rpm 2.6 bar BMEP. The 90% distillation recovery temperature (T90) was $270^{\circ}C$ and $340^{\circ}C$ for the respective cetane number (CN) 30 and 55. It was found that there exists no distinctive discrepancy on exhaust emissions with regards to the different T90s. The high CN (CN55) fuels follow the similar trend of exhaust emissions as observed in CN30 fuels' except that high T90 fuel (CN55-T340) produced higher PM compared to low T90 fuel (CN55-T270). This may come from that high T90 plays an active role in aggravating the degree of fuel-air mixture preparedness before ignition.