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The decarbonization process of the automotive industry and the road transport sector has raised the interest on the development of cleaner fuels. A proper characterization of their properties and behavior under different operating conditions is mandatory to achieve an effective implementation in commercial engines. With this objective, the current work presents a comparison of two injectors from the Engine Combustion Network (ECN), namely Spray A and Spray D injectors, in terms of spray characteristics and combustion behavior for different fuels: diesel, dodecane, Hydrotreated Vegetable Oil (HVO), and two types of oxymethylene ethers (OME1 and OME x). The aim is to analyze how differences in nozzle geometry affect the behavior of different types of fuels. The experiments were carried out in a High Temperature and High Pressure test rig and operating conditions were chosen following ECN guidelines. Visualization techniques such as high speed schlieren imaging, OH* chemiluminescence and diffused back illumination were implemented to analyze the differences in liquid length, vapor penetration, auto ignition, flame lift-off length, and soot formation for both nozzles. In general, results showed the same trend for all the fuels tested: longer liquid length and faster vapor penetration for Spray D, as well as higher ignition delay and longer lift-off length. However, it was found that these parameters were less sensitive to the nozzle diameter for the oxygenated fuels tested. Furthermore, a different trend was observed for OME1, in terms of ignition behavior, in comparison to the other fuels. In terms of soot production, the Spray D nozzle increases its formation with the non-oxygenated fuels. In contrast, no soot was observed with the oxygenated ones under any operating conditions.
José V Pastor; José M García-Oliver; Carlos Micó; Alba A García-Carrero. An experimental study with renewable fuels using ECN Spray A and D nozzles. International Journal of Engine Research 2021, 1 .
AMA StyleJosé V Pastor, José M García-Oliver, Carlos Micó, Alba A García-Carrero. An experimental study with renewable fuels using ECN Spray A and D nozzles. International Journal of Engine Research. 2021; ():1.
Chicago/Turabian StyleJosé V Pastor; José M García-Oliver; Carlos Micó; Alba A García-Carrero. 2021. "An experimental study with renewable fuels using ECN Spray A and D nozzles." International Journal of Engine Research , no. : 1.
E-fuels are a very attractive way for improving the well-to-wheel emissions of CO2 in internal combustion engines. In the particular case of compression ignition engines, the Oxymethylene dimethyl ether (OMEX), an e-fuel with nearly soot-free combustion under mixing-controlled conditions, is a good candidate for the replacement of fossil fuels. However, the Lower Heating Value of OMEX is nearly half of the diesel fuel, which means that much longer injection durations are required in the real engine. In addition, the very low viscosity and lubricity of OMEX can damage the injection system if used pure, but it can be an interesting fuel when blended with conventional diesel. Thus, the main objective of this paper is to evaluate the potential of OMEX-diesel blends to bypass these OMEX limitations whilst keeping low soot formation trends. For this purpose, a single cylinder optical diesel engine at part load was employed. The soot production for the different fuel blends was analyzed by applying three different high-speed imaging techniques: natural luminosity, flame spectroscopy and 2-color pyrometry. Natural luminosity analysis showed that the flame light intensity scales with diesel fraction up to 30% of diesel in the blend. The spectroscopy analysis has revealed that soot formation of OMEX fuel is almost null. When blended with diesel at 50%, although soot formation is still lower than for pure diesel, higher soot levels are obtained in the last stages of the cycle as a consequence of the longer injections required.
José V. Pastor; Antonio García; Carlos Micó; Felipe Lewiski. Simultaneous high-speed spectroscopy and 2-color pyrometry analysis in an optical compression ignition engine fueled with OMEX-diesel blends. Combustion and Flame 2021, 230, 111437 .
AMA StyleJosé V. Pastor, Antonio García, Carlos Micó, Felipe Lewiski. Simultaneous high-speed spectroscopy and 2-color pyrometry analysis in an optical compression ignition engine fueled with OMEX-diesel blends. Combustion and Flame. 2021; 230 ():111437.
Chicago/Turabian StyleJosé V. Pastor; Antonio García; Carlos Micó; Felipe Lewiski. 2021. "Simultaneous high-speed spectroscopy and 2-color pyrometry analysis in an optical compression ignition engine fueled with OMEX-diesel blends." Combustion and Flame 230, no. : 111437.
The development of new piston geometries has shown great potential to achieve the low levels of soot emissions required by regulation. Thus, the present paper aims to characterize the influence of a new piston design over combustion process. It is characterized by the introduction of protrusions around the periphery of the bowl, evenly spaced. The performance of this geometry is compared to other geometries that have been extensively analyzed in literature, under similar operating conditions. To achieve this objective, a single cylinder optical compression ignition engine was used with full-quartz pistons representing three bowl geometries: re-entrant, stepped lip and wave-stepped lip. Two optical techniques (OH∗ chemiluminescence and Natural Luminosity-NL) were applied for identifying the near-stoichiometric zones and the differences in the combustion evolution. The flame movement was analyzed by applying the combustion image velocimetry (CIV) algorithms. In addition, an in-cylinder pressure analysis was performed for each piston at 4.5 bar and 7.5 bar IMEP and the differences in terms of Rate of Heat Release were highlighted. A more intense reverse flow was clearly identified when using wave protrusions inside the bowl. The stepped lip and wave-stepped lip bowl present faster late cycle oxidation with much near-stoichiometric zones than re-entrant piston.
José V. Pastor; Antonio García; Carlos Micó; Felipe Lewiski; Alberto Vassallo; Francesco Concetto Pesce. Effect of a novel piston geometry on the combustion process of a light-duty compression ignition engine: An optical analysis. Energy 2021, 221, 119764 .
AMA StyleJosé V. Pastor, Antonio García, Carlos Micó, Felipe Lewiski, Alberto Vassallo, Francesco Concetto Pesce. Effect of a novel piston geometry on the combustion process of a light-duty compression ignition engine: An optical analysis. Energy. 2021; 221 ():119764.
Chicago/Turabian StyleJosé V. Pastor; Antonio García; Carlos Micó; Felipe Lewiski; Alberto Vassallo; Francesco Concetto Pesce. 2021. "Effect of a novel piston geometry on the combustion process of a light-duty compression ignition engine: An optical analysis." Energy 221, no. : 119764.
Considering the need of pollutant emissions reduction and the high cost of the after-treatment systems, in-cylinder solutions for pollutant reduction are becoming more and more relevant. Among different proposals, new piston geometries are considered an attractive solution for reducing both soot and nitrogen oxides emissions in compression ignition engines. For this reason, this paper evaluates the soot formation and combustion characteristics of a novel piston geometry proposal, called stepped lip-wave, for light-duty engines. It is compared with other two well-known bowl geometries: re-entrant and stepped lip. The study was performed in an optical single-cylinder direct injection compression ignition engine. Two optical techniques (2 color pyrometry and OH* chemiluminescence) were applied for analyzing soot formation in each piston geometry. Test were performed at different engine loads, fuel injection characteristics and exhaust gas recirculation configuration. The re-entrant piston presents higher soot formation and a slower late oxidation process in comparison with the other two geometries. Stepped lip and stepped lip-wave present similar soot formation levels. However, stepped lip-wave showed a more efficient and faster soot oxidation process during the final combustion stages. Results confirm the potential of the stepped lip-wave concept to reduce soot emissions and achieve a cleaner energy production system.
José V Pastor; Antonio García; Carlos Micó; Felipe Lewiski. Soot reduction for cleaner Compression Ignition Engines through innovative bowl templates. International Journal of Engine Research 2020, 1 .
AMA StyleJosé V Pastor, Antonio García, Carlos Micó, Felipe Lewiski. Soot reduction for cleaner Compression Ignition Engines through innovative bowl templates. International Journal of Engine Research. 2020; ():1.
Chicago/Turabian StyleJosé V Pastor; Antonio García; Carlos Micó; Felipe Lewiski. 2020. "Soot reduction for cleaner Compression Ignition Engines through innovative bowl templates." International Journal of Engine Research , no. : 1.
The stringent emission regulations have motivated the development of cleaner fuels as diesel surrogates. However, their different physical-chemical properties make the study of their behavior in compression ignition engines essential. In this sense, optical techniques are a very effective tool for determining the spray evolution and combustion characteristics occurring in the combustion chamber. In this work, quantitative parameters describing the evolution of diesel-like sprays such as liquid length, spray penetration, ignition delay, lift-off length and flame penetration as well as the soot formation were tested in a constant high pressure and high temperature installation using schlieren, OH∗ chemiluminescence and diffused back-illumination extinction imaging techniques. Boundary conditions such as rail pressure, chamber density and temperature were defined using guidelines from the Engine Combustion Network (ECN). Two paraffinic fuels (dodecane and a renewable hydrotreated vegetable oil (HVO)) and two oxygenated fuels (methylal identified as OME1 and a blend of oxymethylene ethers, identified as OMEx) were tested and compared to a conventional diesel fuel used as reference. Results showed that paraffinic fuels and OMEx sprays have similar behavior in terms of global combustion metrics. In the case of OME1, a shorter liquid length, but longer ignition delay time and flame lift-off length were observed. However, in terms of soot formation, a big difference between paraffinic and oxygenated fuels could be appreciated. While paraffinic fuels did not show any significant decrease of soot formation when compared to diesel fuel, soot formed by OME1 and OMEx was below the detection threshold in all tested conditions.
José V. Pastor; José M. García-Oliver; Carlos Micó; Alba A. García-Carrero; Arantzazu Gómez. Experimental Study of the Effect of Hydrotreated Vegetable Oil and Oxymethylene Ethers on Main Spray and Combustion Characteristics under Engine Combustion Network Spray A Conditions. Applied Sciences 2020, 10, 5460 .
AMA StyleJosé V. Pastor, José M. García-Oliver, Carlos Micó, Alba A. García-Carrero, Arantzazu Gómez. Experimental Study of the Effect of Hydrotreated Vegetable Oil and Oxymethylene Ethers on Main Spray and Combustion Characteristics under Engine Combustion Network Spray A Conditions. Applied Sciences. 2020; 10 (16):5460.
Chicago/Turabian StyleJosé V. Pastor; José M. García-Oliver; Carlos Micó; Alba A. García-Carrero; Arantzazu Gómez. 2020. "Experimental Study of the Effect of Hydrotreated Vegetable Oil and Oxymethylene Ethers on Main Spray and Combustion Characteristics under Engine Combustion Network Spray A Conditions." Applied Sciences 10, no. 16: 5460.
The use of alternative fuels in compression ignition engines, either completely or partially replacing the conventional ones, have potential to reduce pollutant emissions (especially soot). However, some of these fuels do not provide good ignition features under diesel engine like conditions, which affects engine efficiency. Thus, in order to extend the application of alternative fuels, the current research proposes the use of a laser induced plasma ignition system to assist on the combustion of blends of fuels with less reactivity than pure diesel. This fuel has been chosen as the base component and it has been mixed with gasoline (as the low-reactivity fuel) in different ratios as an example of fuels with very different reactivity properties. Tests have been performed in a single cylinder optically accessible engine, allowing deeper study of combustion development and soot formation. For different in-cylinder conditions and fuel blends, the effect of laser induced plasma ignition system has been evaluated at different crank angle degrees and locations inside the combustion chamber. The application of these blends under low-reactivity engine conditions show that combustion efficiency is dramatically affected. However, the study proves that it is possible to control blend ignition delay and flame lift-off length by means of laser induced plasma. Besides, using the proper ignition system configuration, combustion characteristics similar to those of diesel fuel autoignition can be achieved for high gasoline substitution rates. They lead to similar energy release rates, which confirms that diesel-gasoline blends can reach a combustion efficiency close to pure diesel, while a strong reduction on soot formation was also obtained. These results open a door to efficiency improvement and pollutant reduction by means of a highly tunable ignition of alternative fuel blends.
José V. Pastor; José M. García-Oliver; Antonio García; Carlos Micó. Combustion improvement and pollutants reduction with diesel-gasoline blends by means of a highly tunable laser plasma induced ignition system. Journal of Cleaner Production 2020, 271, 122499 .
AMA StyleJosé V. Pastor, José M. García-Oliver, Antonio García, Carlos Micó. Combustion improvement and pollutants reduction with diesel-gasoline blends by means of a highly tunable laser plasma induced ignition system. Journal of Cleaner Production. 2020; 271 ():122499.
Chicago/Turabian StyleJosé V. Pastor; José M. García-Oliver; Antonio García; Carlos Micó. 2020. "Combustion improvement and pollutants reduction with diesel-gasoline blends by means of a highly tunable laser plasma induced ignition system." Journal of Cleaner Production 271, no. : 122499.
Recent research has demonstrated that a reduction in pollutant emissions of diesel engines can be achieved by using high octane fuels such as gasoline, methane or liquefied petroleum gas. Therefore in this study, the focus was to investigate the influence of blends of Diesel and Gasoline on combustion characteristics such as ignition delay, rate of heat release and lift-off length, as well as the influence on soot formation. The experiments were carried out in a test rig with optical access which mimics a single-cylinder diesel engine. Four blends were tested: one blend with 100% diesel and then three diesel-gasoline-blends 30%, 50% and 70% of gasoline. The blends were made in volumetric proportions and were injected using a common rail injection system without any kind of modification. The ignition delay and the apparent heat release were obtained by means of the in-cylinder pressure signal. Furthermore, the combustion development and the soot formation were studied using three optical techniques: OH* Chemiluminescence, Natural Luminosity and Diffused Back Illumination extinction imaging (DBI). Different engine operating conditions were analyzed. Results showed that ID increases with the gasoline content in the blend. Similarly, as the reacting time increased, the lift-off length was longer. On the other hand, the apparent rate of heat release decreased due to a reduction of the fuel injection rate, which is depends on the density of the blend. In addition, differences in the flame radiation were also observed. Gasoline-diesel blends had less luminosity, which is related to less soot formation. To confirm this, the KL factor obtained from the DBI technique was determined and it was concluded that increasing the gasoline fraction in the blend reduces the soot formation.
Jose Vicente Pastor; Antonio Garcia; Carlos Micó; Alba A. García-Carrero. Experimental Study of the Influence of Gasoline–Diesel Blends on the Combustion Process and Soot Formation under Diesel Engine-Like Conditions. Energy & Fuels 2020, 34, 5589 -5598.
AMA StyleJose Vicente Pastor, Antonio Garcia, Carlos Micó, Alba A. García-Carrero. Experimental Study of the Influence of Gasoline–Diesel Blends on the Combustion Process and Soot Formation under Diesel Engine-Like Conditions. Energy & Fuels. 2020; 34 (5):5589-5598.
Chicago/Turabian StyleJose Vicente Pastor; Antonio Garcia; Carlos Micó; Alba A. García-Carrero. 2020. "Experimental Study of the Influence of Gasoline–Diesel Blends on the Combustion Process and Soot Formation under Diesel Engine-Like Conditions." Energy & Fuels 34, no. 5: 5589-5598.