| 1. |
- Beatrice, Carlo, et al.
(författare)
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Experimental Assessment on Exploiting Low Carbon Ethanol Fuel in a Light-Duty Dual-Fuel Compression Ignition Engine
- 2020
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Ingår i: Applied Sciences (Switzerland). - : MDPI AG. - 2076-3417. ; 10:20
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Tidskriftsartikel (refereegranskat)abstract
- Compression ignition (CI) engines are widely used in modern society, but they are also recognized as a significative source of harmful and human hazard emissions such as particulate matter (PM) and nitrogen oxides (NOx). Moreover, the combustion of fossil fuels is related to the growing amount of greenhouse gas (GHG) emissions, such as carbon dioxide (CO2). Stringent emission regulatory programs, the transition to cleaner and more advanced powertrains and the use of lower carbon fuels are driving forces for the improvement of diesel engines in terms of overall efficiency and engine-out emissions. Ethanol, a light alcohol and lower carbon fuel, is a promising alternative fuel applicable in the dual-fuel (DF) combustion mode to mitigate CO2 and also engine-out PM emissions. In this context, this work aims to assess the maximum fuel substitution ratio (FSR) and the impact on CO2 and PM emissions of different nozzle holes number injectors, 7 and 9, in the DF operating mode. The analysis was conducted within engine working constraints and considered the influence on maximum FSR of calibration parameters, such as combustion phasing, rail pressure, injection pattern and exhaust gas recirculation (EGR). The experimental tests were carried out on a single-cylinder light-duty CI engine with ethanol introduced via port fuel injection (PFI) and direct injection of diesel in two operating points, 1500 and 2000 rpm and at 5 and 8 bar of brake mean effective pressure (BMEP), respectively. Noise and the coefficient of variation in indicated mean effective pressure (COVIMEP) limits have been chosen as practical constraints. In particular, the experimental analysis assesses for each parameter or their combination the highest ethanol fraction that can be injected. To discriminate the effect on ethanol fraction and the combustion process of each parameter, a one-at-a-time-factor approach was used. The results show that, in both operating points, the EGR reduces the maximum ethanol fraction injectable; nevertheless, the ethanol addition leads to outstanding improvement in terms of engine-out PM. The adoption of a 9 hole diesel injector, for lower load, allows reaching a higher fraction of ethanol in all test conditions with an improvement in combustion noise, on average 3 dBA, while near-zero PM emissions and a reduction can be noticed, on the average of 1 g/kWh, and CO2 compared with the fewer nozzle holes case. Increasing the load insensitivity to different holes number was observed.
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| 2. |
- Saccullo, Michael, 1984
(författare)
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Alcohol Flexible Dual-Fuel Direct Injection Engine
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Laws concerning emissions from HD internal combustion engines are becoming increasingly stringent in terms of local emissions and emissions concerning global warming such as lowering tailpipe CO2. New engine technologies are needed to satisfy these new requirements and to reduce fossil fuel dependency and increase renewable fuels in the transportation sector. One way to achieve both objectives can be to partially replace fossil fuels with alternatives that are sustainable with respect to emissions of greenhouse gases and engine out particulates. Also a decrease in NOx can be achieved. Suitable candidates are ethanol or methanol. The thesis presented here summarizes results from publications and additional results presented here with the aim to investigate the possible advantages of combusting low carbon alcohol fuels in dual-fuel configuration in a HD Diesel engine - in particular, the potential to greatly reduce particulate emissions and thereby bypass the soot-NOx tradeoff and lowering tailpipe CO2 emissions. It was complimented by additional results presented in the kappa itself. Ethanol sprays were studied in a high pressure/temperature spray chamber at typical engine condition with gas densities of about 27 kg/m^3 at around 550 C and around 60 bar. Spray parameters, such as the liquid cone angle, liquid penetration length and vapor penetration at injection pressures up to 2200 bar, were investigated. The characterization of those sprays was followed by an investigation focusing on the combustion of alcohol fuels in a single cylinder engine. Methanol, ethanol and E85 were chosen, but because of their poor auto-ignition properties, a pilot Diesel injection was used to initiate the combustion process. One of the alcohol fuels and Diesel were injected directly but separately, necessitating the use of two separate common rail systems together with a newly designed cylinder head and adapted injection nozzles. The dual fuel system's combustion properties were compared to those of pure Diesel with the same dual injection strategy. The injection pressure on the alcohol side were varied up to 2000 bar and investigations were carried out at low, medium and high speed-load points, with and without EGR. The investigated low carbon fuels outperformed Diesel under all tested conditions in terms of thermal efficiency and indicated specific NOx, soot and CO2 emissions. Thermal efficiency was increased by up to 3.5 %-points and simultaneously soot emissions were lowered by a factor of 40 or more and NOx by 20 %. ISCO2 emissions were down by up to 25 %. The fuel substitution ratio was over 95 % and the combustion stability was not compromised.
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| 3. |
- Saccullo, Michael, 1984, et al.
(författare)
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Alcohol flexible HD single cylinder diesel engine tests with separate dual high pressure direct fuel injection
- 2021
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361. ; 294
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Tidskriftsartikel (refereegranskat)abstract
- Both greenhouse gas (GHG) emissions and local emissions from heavy duty (HD) Diesel engines must be greatly reduced to make transportation sustainable and comply with increasingly stringent emissions regulations. The fuel flexible engine concept for HD Diesel engines uses a dual fuel direct injection system in which ignition of the main alcohol fuel, either methanol or ethanol, is induced by a small Diesel pilot injection delivered via a separate direct injector. The objective of this investigation was to find ways to combine the advantages of conventional Diesel engines with the advantages of low carbon fuels and to thereby bypass the soot-NOx-trade-off. Experiments were conducted using a modified single-cylinder HD engine and three fuels (methanol, ethanol, and a reference Diesel fuel) to determine how the choice of fuel affected the engine's combustion behaviour, emissions and fuel efficiency. Injection pressures on the alcohol side were varied up to 1500 bar and the investigation was carried out at low, medium and high speed-load points. The alcohol fuels significantly outperformed Diesel fuel under all tested conditions (with and without exhaust gas recirculation (EGR)). Indicated thermal efficiency was increased by up to 3.5%-points and simultaneously soot emissions were lowered by a factor of 40 or more and NOx by 20%. Combustion stability and emissions were in the same range as for Diesel but replacing more than 95 % of the fossil Diesel with an alcohol fuel.
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| 4. |
- Saccullo, Michael, 1984, et al.
(författare)
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CI Methanol and Ethanol combustion using ignition improver
- 2019
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
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Konferensbidrag (refereegranskat)abstract
- To act on global warming, CO2 emissions must be reduced. This will require a reduction in the use of fossil fuels for transportation. Because of the large quantities of fossil fuels used in transportation, sources of renewable fuels other than biomass will have to be explored, such as electrofuels synthesized from CO2 using renewable electricity. Potential electrofuels include methanol and ethanol, which have shown promising results in SI engines. However, their low cetane numbers make these fuels unsuitable for CI engines because of their poor auto-ignition qualities. The main objective of this study was to evaluate the viability of using methanol and ethanol in CI engines at compression ratios of 16.7 and 20 with a pilot-main injection strategy in the PPC/CI regime. Single cylinder engine tests on a heavy duty engine were performed under medium load conditions (1262 rpm and 172 Nm). The higher compression ratio generated significantly better indicated thermal efficiencies, lower brake-specific NOx emissions, and less combustion noise. Soot emissions were well below current tailpipe emission limits in all cases.
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| 5. |
- Saccullo, Michael, 1984, et al.
(författare)
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Dual Fuel Methanol and Diesel Direct Injection HD Single Cylinder Engine Tests
- 2018
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627. ; 2018-April
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Tidskriftsartikel (refereegranskat)abstract
- Laws concerning emissions from heavy duty (HD) internal combustion engines are becoming increasingly stringent. New engine technologies are needed to satisfy these new requirements and to reduce fossil fuel dependency. One way to achieve both objectives can be to partially replace fossil fuels with alternatives that are sustainable with respect to emissions of greenhouse gases, particulates and nitrogen oxides (NOx). A suitable candidate is methanol. The aim of the study presented here was to investigate the possible advantages of combusting methanol in a heavy duty Diesel engine. Those are, among others, lower particulate emissions and thereby bypassing the NOx-soot trade-off. Because of methanol's poor auto-ignition properties, Diesel was used as an igniting sources and both fuels were separately direct injected. Therefore, two separate standard common rail Diesel injection systems were used together with a newly designed cylinder head and adapted injection nozzles. This study serves as a proof-of-concept, demonstrating that methanol can successfully be used in a high pressure Diesel injection system. Additionally, the combustion properties of the dual fuel system were compared to those of pure Diesel with the same dual injection strategy. Methanol offered comparable combustion efficiencies to conventional Diesel with lower NOx and significantly lower soot emissions. A design of experiments study was performed to characterize the methanol-diesel system's behavior in detail at a single speed-load point. A sweet spot analysis showed potential for optimizing the given setup towards even higher indicated gross efficiency with very low soot and low NOx.
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| 6. |
- Saccullo, Michael, 1984, et al.
(författare)
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High Pressure Ethanol Injection under Diesel-Like Conditions
- 2017
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627. ; 2017-March:March
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Tidskriftsartikel (refereegranskat)abstract
- Laws concerning to emissions from heavy duty (HD) internal combustion engines are becoming increasingly stringent. New engine technologies are therefore needed to satisfy these new legal requirements and reduce fossil fuel dependency. One way to achieve both objectives is to partially replace fossil fuels with alternatives that are more sustainable with respect to emissions of greenhouse gas, particulates and NOx. As a first step towards the development of a direct injected dual fuel engine using diesel fuel and renewable alcohols such as methanol or ethanol, we have studied ethanol (E100) sprays generated with a standard high pressure diesel fuel injection system in a high pressure/temperature spray chamber with optical access. The experiments were performed at a gas density of ∼27kg/m3 at ∼550 °C and ∼60 bar, representing typical operating conditions for a HD engine at low loads. High speed video images of the developing sprays were recorded, enabling measurement of spray parameters such as the liquid cone angle, liquid penetration length and vapor penetration at injection pressures between 500 and 2200 bar. The results obtained provide insight into the fuel-air mixing process. Moreover, they serve as a proof-of-concept demonstrating that ethanol can be used successfully in a high pressure Diesel injection system.
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| 7. |
- Saccullo, Michael, 1984
(författare)
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Methanol Diesel Dual Fuel Direct Injection in a HD-CI Engine
- 2018
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Laws concerning emissions from heavy duty (HD) internal combustion engines are becoming increasingly stringent. New engine technologies are needed to satisfy these new requirements and to reduce fossil fuel dependency. One way to achieve both objectives can be to partially replace fossil fuels with alternatives that are sustainable with respect to emissions of greenhouse gases, particulates and nitrogen oxides (NOx). Suitable candidates are ethanol or methanol. The aim of the studies presented here was to investigate the possible advantages of combusting methanol in a heavy duty Diesel engine - in particular, the potential to greatly reduce particulate emissions and thereby bypass the soot-NOx tradeoff. To better understand the fuel-air mixing process in alcohol fuel sprays, ethanol sprays were studied in a high pressure/temperature spray chamber with optical access. The experiments were performed at a gas density of 27kg/m3 at 550 C and 60 bar, representing typical operating conditions for a HD engine at low loads. High speed video images of the developing sprays were recorded, enabling measurement of spray parameters such as the liquid cone angle, liquid penetration length and vapor penetration at injection pressures between 500 and 2200 bar. The results obtained provide insight into the fuel-air mixing process. Having characterized the behavior of alcohol sprays, a second study was conducted to investigate the combustion of alcohol fuels in a Diesel engine. Because of methanol’s poor auto-ignition properties, a pilot Diesel injection was used to initiate the combustion process. The two fuels were injected directly but separately, necessitating the use of two separate standard common rail Diesel injection systems together with a newly designed cylinder head and adapted injection nozzles. The studies serve as a proof-of-concept showing that methanol and ethanol can successfully be used in a high pressure Diesel injection system. The dual fuel system's combustion properties were compared to those of pure Diesel with the same dual injection strategy. Methanol offered comparable combustion efficiencies to conventional Diesel with lower emissions of NOx and significantly lower soot emissions. A design of experiments study was performed to characterize the methanol-diesel system’s behavior in detail at a single speed-load point, and a sweet spot analysis revealed that it may be possible to optimize the tested setup to improve its gross efficiency while maintaining very low soot emissions and low emissions of NOx.
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