Dilution Sensitivity of Particulate Matter Emissions From Reactivity Controlled Compression Ignition Combustion

2015 ◽  
Author(s):  
Wei Fang ◽  
David B. Kittelson ◽  
William F. Northrop
Keyword(s):  
Particulate Matter ◽  
Diesel Combustion ◽  
Compression Ignition ◽  
Total Particulate Matter ◽  
Reactivity Controlled Compression Ignition ◽  
Carbonaceous Particles ◽  
Relative Contribution ◽  
Particulate Matter Emissions ◽  
Soot Emissions ◽  
Hydrous Ethanol

Dual-fuel reactivity-controlled compression ignition (RCCI) combustion can yield high thermal efficiency and simultaneously low NOx and soot emissions. Although soot emissions from RCCI is very low, hydrocarbon emissions are high, potentially resulting in higher than desired total particulate matter (PM) mass and number caused by semi-volatile species converting the particle phase upon primary dilution in the exhaust plume. Such high organic fraction PM is known to be highly sensitive to the dilution conditions used when collecting samples on a filter or when measuring particle number using particle sizing instruments. In this study, PM emissions from a modified single-cylinder diesel engine operating in RCCI and conventional diesel combustion modes were investigated under different dilution conditions. To investigate the effect of the fumigated fuel on the PM emissions, 150 proof hydrous ethanol and gasoline were used as low reactivity fuels to study the relative contribution of fumigant versus directly injected fuel on the PM emissions. Our study found that PM from RCCI combustion is more sensitive to the variation of dilution conditions than PM from single fuel conventional diesel combustion. RCCI PM primarily consisted of semi-volatile organic compounds and a smaller amount of solid carbonaceous particles. The fumigated fuel had a significant effect on the PM emissions characteristics for RCCI combustion. Hydrous ethanol fueled RCCI PM contained a larger fraction of volatile materials and were more sensitive to the variation of dilution conditions compared to the gasoline fueled RCCI mode.

Dilution Sensitivity of Particulate Matter Emissions From Reactivity-Controlled Compression Ignition Combustion

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Wei Fang ◽  
David B. Kittelson ◽  
William F. Northrop
Keyword(s):  
Particulate Matter ◽  
Semivolatile Organic Compounds ◽  
Diesel Combustion ◽  
Compression Ignition ◽  
Total Particulate Matter ◽  
Reactivity Controlled Compression Ignition ◽  
Carbonaceous Particles ◽  
Particulate Matter Emissions ◽  
Soot Emissions ◽  
Hydrous Ethanol

Dual-fuel reactivity-controlled compression ignition (RCCI) combustion can yield high thermal efficiency and simultaneously low NOx and soot emissions. Although soot emissions from RCCI are very low, hydrocarbon (HC) emissions are high, potentially resulting in higher than desired total particulate matter (PM) mass and number caused by semivolatile species converting the particle phase upon primary dilution in the exhaust plume. Such high organic fraction PM is known to be highly sensitive to dilution conditions used when collecting samples on a filter or when measuring particle number using particle sizing instruments. In this study, PM emissions from a modified single-cylinder diesel engine operating in RCCI and conventional diesel combustion (CDC) modes were investigated under controlled dilution conditions. To investigate the effect of the fumigated fuel on the PM emissions, 150 proof hydrous ethanol and gasoline were used as low reactivity fuels. The data reveal that PM from RCCI combustion is more sensitive to the variation of dilution conditions than PM from single fuel conventional diesel combustion. RCCI PM primarily consisted of semivolatile organic compounds and a smaller amount of solid carbonaceous particles. The fumigated fuel had a significant effect on PM emissions' characteristics for RCCI combustion. Hydrous ethanol fueled RCCI PM contained a larger fraction of volatile materials and was more sensitive to the variation of dilution conditions compared to the gasoline fueled RCCI mode.

An Experimental Investigation of Reactivity-Controlled Compression Ignition Combustion in a Single-Cylinder Diesel Engine Using Hydrous Ethanol

2014 ◽  
Vol 137 (3) ◽  
Author(s):  
Wei Fang ◽  
Junhua Fang ◽  
David B. Kittelson ◽  
William F. Northrop
Keyword(s):  
Experimental Investigation ◽  
Diesel Engine ◽  
Thermal Efficiency ◽  
Alternative Fuels ◽  
Compression Ignition ◽  
Reactivity Controlled Compression Ignition ◽  
Single Cylinder ◽  
Diesel Injection ◽  
Soot Emissions ◽  
Hydrous Ethanol

Dual-fuel reactivity-controlled compression ignition (RCCI) combustion using port injection of a less reactive fuel and early-cycle direct injection (DI) of a more reactive fuel has been shown to yield both high thermal efficiency and low NOX and soot emissions over a wide engine operating range. Conventional and alternative fuels such as gasoline, natural gas, and E85 as the lower reactivity fuel in RCCI have been studied by many researchers; however, published experimental investigations of hydrous ethanol use in RCCI are scarce. Making greater use of hydrous ethanol in internal combustion engines has the potential to dramatically improve the economics and life cycle carbon dioxide emissions of using bioethanol. In this work, an experimental investigation was conducted using 150 proof hydrous ethanol as the low reactivity fuel and commercially available diesel as the high reactivity fuel in an RCCI combustion mode at various load conditions. A modified single-cylinder diesel engine was used for the experiments. Based on previous studies on RCCI combustion by other researchers, early-cycle split-injection strategy of diesel fuel was used to create an in-cylinder fuel reactivity distribution to maintain high thermal efficiency and low NOX and soot emissions. At each load condition, timing and mass fraction of the first diesel injection was held constant, while timing of the second diesel injection was swept over a range where stable combustion could be maintained. Since hydrous ethanol is highly resistant to auto-ignition and has large heat of vaporization, intake air heating was needed to obtain stable operations of the engine. The study shows that 150 proof hydrous ethanol can be used as the low reactivity fuel in RCCI through 8.6 bar indicated mean effective pressure (IMEP) and with ethanol energy fraction up to 75% while achieving simultaneously low levels of NOX and soot emissions. With increasing engine load, less intake heating is needed and exhaust gas recirculation (EGR) is required to maintain low NOX emissions.

An Experimental Investigation of Reactivity-Controlled Compression Ignition Combustion in a Single-Cylinder Diesel Engine Using Hydrous Ethanol

2013 ◽  
Author(s):  
Wei Fang ◽  
David B. Kittelson ◽  
William F. Northrop ◽  
Junhua Fang
Keyword(s):  
Experimental Investigation ◽  
Diesel Engine ◽  
Thermal Efficiency ◽  
Compression Ignition ◽  
Reactivity Controlled Compression Ignition ◽  
Engine Load ◽  
Single Cylinder ◽  
Diesel Injection ◽  
Soot Emissions ◽  
Hydrous Ethanol

Dual-fuel reactivity-controlled compression ignition (RCCI) combustion using port injection of a less reactive fuel and early-cycle direct injection of a more reactive fuel has been shown to yield both high thermal efficiency and low NOX and soot emissions over a wide engine operating range. Conventional and alternative fuels such as gasoline, natural gas and E85 as the lower reactivity fuel in RCCI have been studied by many researchers; however, published experimental investigations of hydrous ethanol use in RCCI are scarce. Making greater use of hydrous ethanol in internal combustion engines has the potential to dramatically improve the economics and life cycle carbon dioxide emissions of using bio-ethanol. In this work, an experimental investigation was conducted using 150 proof hydrous ethanol as the low reactivity fuel and commercially-available diesel as the high reactivity fuel in an RCCI combustion mode at various load conditions. A modified single-cylinder diesel engine was used for the experiments. Based on previous studies on RCCI combustion by other researchers, early-cycle split-injection strategy of diesel fuel was used to create an in-cylinder fuel reactivity distribution to maintain high thermal efficiency and low NOX and soot emissions. At each load condition, timing and mass fraction of the first diesel injection was held constant, while timing of the second diesel injection was swept over a range where stable combustion could be maintained. Since hydrous ethanol is highly resistant to auto-ignition and has large heat of vaporization, intake air heating was needed to obtain stable operations of the engine. The study shows that 150 proof hydrous ethanol can be used as the low reactivity fuel in RCCI through 8.6 bar IMEP and with ethanol energy fraction up to 75% while achieving simultaneously low levels of NOX and soot emissions. With increasing engine load, less intake heating is needed and EGR is required to maintain low NOX emissions. Future work will look at stability of hydrous ethanol RCCI at higher engine load.

A Comparison of Low-Load Efficiency Optimization on a Heavy-Duty Engine Operated With Gasoline-Diesel RCCI and CDC

2019 ◽  
Author(s):  
R. C. Willems ◽  
F. P. T. Willems ◽  
N. G. Deen ◽  
L. M. T. Somers
Keyword(s):  
Nitrogen Oxides ◽  
Combustion Regime ◽  
Intake Manifold ◽  
Substantial Contribution ◽  
Diesel Combustion ◽  
Compression Ignition ◽  
Heavy Duty ◽  
Lower Efficiency ◽  
Reactivity Controlled Compression Ignition ◽  
Intake Manifold Pressure

Abstract Upcoming CO2 legislation in Europe is driving heavy-duty vehicle manufacturers to develop highly efficient engines more than ever before. Further improvements to conventional diesel combustion, or adopting the reactivity controlled compression ignition concept are both plausible strategies to comply with mandated targets. This work compares these two combustion regimes by performing an optimization on both using Design of Experiments. The tests are conducted on a heavy-duty, single-cylinder engine fueled with either only diesel, or a combination of diesel and gasoline. Analysis of variance is used to reveal the most influential operating parameters with respect to indicated efficiency. Attention is also directed towards the distribution of fuel energy to quantify individual loss channels. A load-speed combination typical for highway cruising is selected given its substantial contribution to the total fuel consumption of long haul trucks. Experiments show that when the intake manifold pressure is limited to levels that are similar to contemporary turbocharger capabilities, the conventional diesel combustion regime outperforms the dual fuel mode. Yet, the latter displays superior low levels of nitrogen oxides. Suboptimal combustion phasing was identified as main cause for this lower efficiency. By leaving the intake manifold pressure unrestricted, reactivity controlled compression ignition surpasses conventional diesel combustion regarding both the emissions of nitrogen oxides and indicated efficiency.

Experimental Study of Premixed-Charge Compression Ignition Mode in Low Load Fueled With Butanol Isomers and Diesel Binary Fuels in a Common-Rail Diesel Engine

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Zilong Li ◽  
Guan Huang ◽  
Chenxu Jiang ◽  
Yong Qian ◽  
Zhuoyao He ◽  
...  
Keyword(s):  
Experimental Study ◽  
Particulate Matter ◽  
Geometric Mean ◽  
Volume Ratio ◽  
Compression Ignition ◽  
Nox Formation ◽  
Tert Butanol ◽  
Low Load ◽  
Particulate Matter Emissions ◽  
Gas Recirculation

Abstract Low NOx and particulate matter (PM) emissions are simultaneously attempted to implement via an experimental study on diesel/butanol isomers binary fuels in premixed-charge compression ignition (PCCI) mode. N-butanol, iso-butanol, sec-butanol, and tert-butanol were blended with diesel in a certain volume ratio of 0.24:0.76, denoted as N24, I24, S24, and T24, respectively. The indicated thermal efficiency (ITE) of binary fuels in PCCI mode decreases slightly than that in direction injection (DI) mode. T24 obtains higher ITE than the other three test fuels with 50% exhaust gas recirculation (EGR). NOx formation is certainly inhibited more than 60% in PCCI mode, especially when the EGR rate is 50%. PCCI mode produces more CO, HC, and carbonyl emissions than DI mode to varying degrees; under these circumstances, T24 tends to have the lowest emissions among four test fuels, reflecting the potential of tert-butanol as a diesel alternative fuel. Butanol isomers have a vital contribution on particulate matter emissions inhibition for both PM total number and total mass. Tert-butanol tends to form accumulation mode particle, and n-butanol tends to form nucleation mode mainly caused by molecular structure diversity of isomers. The geometric mean diameter of diesel/butanol isomers increases in PCCI mode compared with that in DI mode.

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