Effects of Diesel Injection Parameters in a Heavy Duty Iso-Butanol/Diesel Reactivity Controlled Compression Ignition (RCCI) Engine

2018 ◽  
Author(s):  
Raouf Mobasheri ◽  
Mahdi Seddiq
Keyword(s):  
Compression Ignition ◽  
Heavy Duty ◽  
Reactivity Controlled Compression Ignition ◽  
Injection Parameters ◽  
Diesel Injection

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.

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.

Effects of EGR and Boost Pressure on Reactivity Controlled Compression Ignition (RCCI) Engine at High Load Operating Conditions

2014 ◽  
Author(s):  
Yifeng Wu ◽  
Rolf D. Reitz
Keyword(s):  
Peak Pressure ◽  
Pressure Rise ◽  
High Load ◽  
Operating Conditions ◽  
Boost Pressure ◽  
Compression Ignition ◽  
Effective Pressure ◽  
Reactivity Controlled Compression Ignition ◽  
Brake Mean Effective Pressure ◽  
Diesel Injection

Reactivity Controlled Compression Ignition (RCCI) at engine high load operating conditions is investigated in this study. The effects of EGR and boost pressure on RCCI combustion were studied by using a multi-dimensional computational fluid dynamics (CFD) code. The model was first compared with a previous CFD model, which has been validated against steady-state experimental data of gasoline-diesel RCCI in a multi-cylinder light duty engine. An RCCI piston with a compression ratio of 15:1 was then proposed to improve the combustion and emissions at high load. The simulation results showed that 18 bar indicated mean effective pressure (IMEP) could be achieved with gasoline-diesel RCCI at an EGR rate of 35 % and equivalence ratio of 0.96, while the peak pressure rise rate (PPRR) and engine combustion efficiency could both be controlled at reasonable levels. Simulations using both early and late direct-injection (DI) of diesel fuel showed that RCCI combustion at high load is very sensitive to variations of the exhaust gas recirculation (EGR) amount. Higher IMEP is obtained by using early diesel injection, and it is less sensitive to EGR variation compared to late diesel injection. Reduced unburned hydrocarbon (HC), carbon monoxide (CO), soot and slightly more nitrogen oxides (NOx) emissions were seen for early diesel injection. HC, CO and soot emissions were found to be more sensitive to EGR variation at late diesel injection timings. However, there was little difference in terms of peak pressure, efficiencies, PPRR and phasing under varying EGR rates. The effect of boost pressure on RCCI at high load operating conditions was also studied at different EGR rates. It was found that combustion and emissions were improved, and the sensitivity of the combustion and emission to EGR was reduced with higher boost pressures. In addition, cases with similar combustion phasing and reasonable PPRR were analyzed by using an experimentally validated GT-Power model. The results indicated that although higher IMEP was generated at higher boost pressures, the brake mean effective pressure (BMEP) was similar compared to that obtained with lower boost pressures due to higher pumping losses.

Assessment of the impacts of combustion chamber bowl geometry and injection timing on a reactivity controlled compression ignition engine at low and high load conditions

2020 ◽  
pp. 146808742096121
Author(s):  
Bahram Jafari ◽  
Mahdi Seddiq ◽  
Seyyed Mostafa Mirsalim
Keyword(s):  
Combustion Chamber ◽  
Fuel Consumption ◽  
High Load ◽  
Injection Timing ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Load Range ◽  
Reactivity Controlled Compression Ignition ◽  
Diesel Injection ◽  
Load Conditions

The present paper aims to assess the impacts of diesel injection timing and two bowl geometries including re-entrant and wide-shallow combustion chambers on the combustion characteristics, emissions formation, and fuel consumption in a reactivity controlled compression ignition diesel engine under low and high load (five and nine bar indicating mean effective pressure) conditions. The results revealed that diesel injection at −60 CA ATDC under low load conditions significantly decreased soot and NOx emissions simultaneously for both piston bowl geometries. The use of the wide-shallow chamber decreased the period of the ignition delay and increased the engine operable load range as a result of more stable combustion under high-load conditions compared to the re-entrant chamber. Moreover, at all diesel injection timings, the indicated specific fuel consumption was decreased by nearly 4.8 and 6.6% under low and high load conditions, respectively when the wide-shallow combustion chamber was used since the heat transfer loss was lower than that of the re-entrant chamber. However, NOx emission under high load conditions at the center of the combustion chamber and more soot emission in the exhaust gas are two disadvantages of the wide-shallow chamber versus the re-entrant combustion chamber.

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.

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