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Bengt Johansson - One of the best experts on this subject based on the ideXlab platform.
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combustion stability study of partially premixed combustion by high pressure multiple injections with low Octane Fuel
Applied Energy, 2019Co-Authors: Qinglong Tang, Hao Shi, Jaeheon Sim, Junseok Chang, Gaetano Magnotti, Raman Vallinayagam, Bengt JohanssonAbstract:Abstract This work is the second part of a study on low-load combustion stability for gasoline partially premixed combustion. In part 1, we investigated the sensitivity of the intake air temperature to combustion stability. In part 2, we evaluate the potential of the multiple-injection strategy along with the intake air temperature sensitivity to promote low-load combustion stability using low-Octane gasoline Fuel. The experiments were carried out in a fully transparent, single-cylinder, compression-ignition engine. The spray/wall interaction, particularly the Fuel trapping in the piston crevice zone, was visualized by Fuel-tracer planar laser-induced fluorescence for the first time in experiments. The in-cylinder combustion process of natural flame luminosity was captured by a high-speed color camera. By employing a multiple-injection strategy, the minimum intake air temperature can be further reduced from 70 °C (single injection) to 50 °C for target stable combustion. The combustion stability and engine performance were further improved by increasing the Fuel injection pressure. For instance, with the triple-injection strategy at a higher Fuel-injection pressure of 800 bar, the indicated mean effective pressure was increased by 24% when compared to that of the single-injection strategy. A stronger interaction among Fuel spray jets, the piston, and the cylinder wall was observed for multiple injections with higher injection pressure, leading to higher unburned hydrocarbon (UHC) and carbon monoxide (CO) along with a more pronounced pool fire in the squish zone. The double-injection strategy resulted in lower UHC and CO emissions when compared to the triple-injection strategy. Applying a narrow spray angle injector with re-entrant combustion chamber is suggested for optimizing the spray/wall interaction.
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combustion stability study of partially premixed combustion with low Octane Fuel at low engine load conditions
Applied Energy, 2019Co-Authors: Vallinayagam Raman, Qinglong Tang, Hao Shi, Jaeheon Sim, Junseok Chang, Gaetano Magnotti, Bengt JohanssonAbstract:Abstract The study aims to investigate the sensitivity of combustion stability to the intake air temperature for partially premixed combustion (PPC). The experiments were carried out in a full view optical engine at low load condition. The ω shape optical piston crown as same as the actual product piston, rather than the flat crown piston used in the previous study, was employed for the present experimental test. The continuous-fire mode rather than the skip-fire mode was used to run the optical engine ensuring the similarity to the actual engine operating conditions. The interaction among Fuel spray jets, piston and cylinder wall was visualized by Fuel-tracer planar laser-induced fluorescence. The high-speed combustion images were processed to determine the combustion stratification based on the natural flame luminosity. The combustion phasing, maximum in-cylinder pressure, and indicated mean effective pressure (IMEP) were compared at various intake temperatures. The results showed that the lower intake temperature could be used for achieving better combustion stability at low load condition along with the retarded CA50, the lower maximum in-cylinder pressure, and the higher IMEP. 70 °C was the lower limit of intake temperature to achieve stable PPC operation with the single-injection strategy. The same trend of the combustion characteristics with respect to the start of injection timing was confirmed at various intake temperatures. The combustion stratification analysis indicated more inhomogeneous low-temperature combustion with decreased natural flame luminosity and increased soot emission when the intake temperature reduced from 120 °C to 70 °C. Nitrogen oxides emission decreased when compared to the higher intake temperature cases at the expense of increased unburned hydrocarbon and carbon monoxide emissions at PPC mode. The Fuel tracer measurements showed that most of the injected Fuel hit on the piston top and only less amount of Fuel was injected into the piston crown bowl at PPC mode due to the wider spray umbrella angle. The Fuel trapped in crevice zone was verified as an important source for the unburned hydrocarbon and carbon monoxide emissions at PPC mode. The injector dribbling during the late stage of combustion attributed to soot formation. The injector with a relatively narrow spray umbrella angle was suggested for optimized interaction among the Fuel spray jets, piston and the cylinder wall at PPC mode.
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low Octane Fuel composition effects on the load range capability of partially premixed combustion
Fuel, 2014Co-Authors: Caj Niels Leermakers, P Peterchristian C Bakker, Bcw Bas Nijssen, Lmt Bart Somers, Bengt JohanssonAbstract:To determine the influence of physical and chemical properties of Fuels’ load range capacity in partially premixed combustion, seven Fuels have been blended, with a fixed RON70 reactivity. Four of these Fuels are blended from refinery streams, with different boiling ranges, aromatic- and bio-content. Furthermore, three ternary mixtures of Toluene, n-Heptane, Ethanol and iso-Octane are used, of which the aromatics (toluene) and oxygenate (ethanol) content are varied. The load range capacity of these Fuels is determined based on their Fuel efficiency, smoking tendency and its sensitivity to the Fuel pressure used, nitrogen oxides emissions, and combustion efficiency and stability at low load and engine speed.
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Extending the Operating Region of Multi-Cylinder Partially Premixed Combustion using High Octane Number Fuel
SAE Technical Paper Series, 2011Co-Authors: Magnus Lewander, Bengt Johansson, Per TunestålAbstract:Partially Premixed Combustion (PPC) is a combustion concept by which it is possible to get low smoke and NOx emissions simultaneously. PPC requires high EGR levels to extend the ignition delay so that air and Fuel mix prior to combustion to a larger extent than with conventional diesel combustion. This paper investigates the operating region of single injection PPC for three different Fuels; Diesel, low Octane gasoline with similar characteristics as diesel and higher Octane standard gasoline. Limits in emissions are defined and the highest load that fulfills these requirements is determined. The investigation shows the benefits of using high Octane number Fuel for Multi-Cylinder PPC. With high Octane Fuel the ignition delay is made longer and the operating region of single injection PPC can be extended significantly. Experiments are carried out on a multi-cylinder heavy-duty engine at low, medium and high speed. (Less)
Qinglong Tang - One of the best experts on this subject based on the ideXlab platform.
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combustion stability study of partially premixed combustion by high pressure multiple injections with low Octane Fuel
Applied Energy, 2019Co-Authors: Qinglong Tang, Hao Shi, Jaeheon Sim, Junseok Chang, Gaetano Magnotti, Raman Vallinayagam, Bengt JohanssonAbstract:Abstract This work is the second part of a study on low-load combustion stability for gasoline partially premixed combustion. In part 1, we investigated the sensitivity of the intake air temperature to combustion stability. In part 2, we evaluate the potential of the multiple-injection strategy along with the intake air temperature sensitivity to promote low-load combustion stability using low-Octane gasoline Fuel. The experiments were carried out in a fully transparent, single-cylinder, compression-ignition engine. The spray/wall interaction, particularly the Fuel trapping in the piston crevice zone, was visualized by Fuel-tracer planar laser-induced fluorescence for the first time in experiments. The in-cylinder combustion process of natural flame luminosity was captured by a high-speed color camera. By employing a multiple-injection strategy, the minimum intake air temperature can be further reduced from 70 °C (single injection) to 50 °C for target stable combustion. The combustion stability and engine performance were further improved by increasing the Fuel injection pressure. For instance, with the triple-injection strategy at a higher Fuel-injection pressure of 800 bar, the indicated mean effective pressure was increased by 24% when compared to that of the single-injection strategy. A stronger interaction among Fuel spray jets, the piston, and the cylinder wall was observed for multiple injections with higher injection pressure, leading to higher unburned hydrocarbon (UHC) and carbon monoxide (CO) along with a more pronounced pool fire in the squish zone. The double-injection strategy resulted in lower UHC and CO emissions when compared to the triple-injection strategy. Applying a narrow spray angle injector with re-entrant combustion chamber is suggested for optimizing the spray/wall interaction.
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combustion stability study of partially premixed combustion with low Octane Fuel at low engine load conditions
Applied Energy, 2019Co-Authors: Vallinayagam Raman, Qinglong Tang, Hao Shi, Jaeheon Sim, Junseok Chang, Gaetano Magnotti, Bengt JohanssonAbstract:Abstract The study aims to investigate the sensitivity of combustion stability to the intake air temperature for partially premixed combustion (PPC). The experiments were carried out in a full view optical engine at low load condition. The ω shape optical piston crown as same as the actual product piston, rather than the flat crown piston used in the previous study, was employed for the present experimental test. The continuous-fire mode rather than the skip-fire mode was used to run the optical engine ensuring the similarity to the actual engine operating conditions. The interaction among Fuel spray jets, piston and cylinder wall was visualized by Fuel-tracer planar laser-induced fluorescence. The high-speed combustion images were processed to determine the combustion stratification based on the natural flame luminosity. The combustion phasing, maximum in-cylinder pressure, and indicated mean effective pressure (IMEP) were compared at various intake temperatures. The results showed that the lower intake temperature could be used for achieving better combustion stability at low load condition along with the retarded CA50, the lower maximum in-cylinder pressure, and the higher IMEP. 70 °C was the lower limit of intake temperature to achieve stable PPC operation with the single-injection strategy. The same trend of the combustion characteristics with respect to the start of injection timing was confirmed at various intake temperatures. The combustion stratification analysis indicated more inhomogeneous low-temperature combustion with decreased natural flame luminosity and increased soot emission when the intake temperature reduced from 120 °C to 70 °C. Nitrogen oxides emission decreased when compared to the higher intake temperature cases at the expense of increased unburned hydrocarbon and carbon monoxide emissions at PPC mode. The Fuel tracer measurements showed that most of the injected Fuel hit on the piston top and only less amount of Fuel was injected into the piston crown bowl at PPC mode due to the wider spray umbrella angle. The Fuel trapped in crevice zone was verified as an important source for the unburned hydrocarbon and carbon monoxide emissions at PPC mode. The injector dribbling during the late stage of combustion attributed to soot formation. The injector with a relatively narrow spray umbrella angle was suggested for optimized interaction among the Fuel spray jets, piston and the cylinder wall at PPC mode.
K V Gopalakrishnan - One of the best experts on this subject based on the ideXlab platform.
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DEVICES TO IMPROVE THE PERFORMANCE OF A CONVENTIONAL TWO-STROKE SPARK IGNITION ENGINE
2020Co-Authors: Ramesh B Poola, B Nagalingam, K V GopalakrishnanAbstract:ABSTRACT This paper presents research efforts made in three different phases with the objective of improving the Fuel economy of and reducing exhaust emissions from conventional, carbureted, two-stroke spark ignition (SI) engines, which are widely employed in two-wheel transportation in India. A review concerning the existing two-stroke engine technology for this application is included. In the first phase, a new scavenging system was developed and tested to reduce the loss of fresh charge through the exhaust port. In the second phase, the following measures were carried out to improve the combustion process: (i) using an in-cylinder catalyst, such as copper, chromium, and nickel, in the form of coating; (ii) providing moderate thermal insulation in the combustion chamber, either by depositing thin ceramic material or by metal inserts; (iii) developing a high-energy ignition system; and (iv) employing high-Octane Fuel, such as methanol, ethanol, eucalyptus oil, and orange oil, as a blending agent with gasoline. Based on the effectiveness of the above measures, an optimized design was developed in the final phase to achieve improved performance. Test results indicate that with an optimized two-stroke SI engine, the maximum percentage improvement in brake thermal efficiency is about 3 I%, together with a reduction of 3400 ppm in hydrocarbons (HC) and 3% by volume of carbon monoxide (CO) emissions over the normal engine (at 3 kW, 3000 rpm). Higher cylinder peak pressures (3-5 bar), lower ignition delay (2-4 OCA), and shorter combustion duration (4-10 OCA) are obtained. The knock-limited power output is also enhanced by 12.7% at a high compression ratio (CR) of 9:l. The proposed modifications in the optimized design are simple, low-cost, and easy to adopt for both production and existing engines
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performance studies with biomass derived high Octane Fuel additives in a two stroke spark ignition engine
Biomass & Bioenergy, 1994Co-Authors: Ramesh B Poola, B Nagalingam, K V GopalakrishnanAbstract:Abstract The intensive search for alternative Fuels for spark-ignition engines has focused attention on Fuels which can be derived from biomass. In this regard, orange oil and eucalyptus oil are found to be potential candidates for spark-ignition engines. Their properties are similar to gasoline in nature and they are miscible with gasoline without any phase separation. They can be used in spark-ignition engines with little engine modification as a blend with gasoline Fuel. The high Octane value of these Fuels can enhance the Octane value of the Fuel when it is blended with low-Octane gasoline. Hence, the knock-limited compression ratio (CR) can be further increased when these Fuels are blended with gasoline. In the present work, 20% by volume of orange oil and eucalyptus oil were blended separately with gasoline and the performance, combustion and exhaust emission characteristics were evaluated at two different compression ratios. Test results indicate that the performance of Fuel blends was much better than the gasoline Fuel, in particular at the higher compression ratio. Hydrocarbons and carbon monoxide emission levels in the engine exhaust were considerably reduced with the Fuel blends at both the compression ratios tested. Between the two Fuel blends tested, eucalyptus oil blend provides better performance than the orange oil blend. The maximum percentage improvement in the brake thermal efficiency obtained with eucalyptus oil blend is about 20.5% at 2 kW, 3000 r.p.m. and CR 9 over the normal gasoline engine.
Dave Richardson - One of the best experts on this subject based on the ideXlab platform.
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dual injection as a knock mitigation strategy using pure ethanol and methanol
SAE 2012 World Congress & ExhibitionSAE International, 2012Co-Authors: Ritchie Daniel, Chongming Wang, Hongming Xu, Guohong Tian, Dave RichardsonAbstract:For spark ignition (SI) engines, the optimum spark timing is crucial for maximum efficiency. However, as the spark timing is advanced, so the propensity to knock increases, thus compromising efficiency. One method to suppress knock is to use high Octane Fuel additives. However, the blend ratio of these additives cannot be varied on demand. Therefore, with the advent of aggressive downsizing, new knock mitigation techniques are required. Fortuitously, there are two wellknown lower alcohols which exhibit attractive knock mitigation properties: ethanol and methanol. Both not only have high Octane ratings, but also result in greater charge-cooling than with gasoline. In the current work, the authors have exploited these attractive properties with the dual-injection, or the dual-Fuel concept (gasoline in PFI and Fuel additive in DI) using pure ethanol and methanol. The single cylinder engine results at 1500 rpm (λ=1) show benefits to indicated efficiency and emissions (HC, CO and CO2) at almost every load (4.5 bar to 8.5 bar IMEP) compared to GDI. This is because the spark timing can be significantly advanced despite the use of relatively low blends (≤50%, by volume), which lowers the combustion duration and improves the conversion of Fuel energy into useful work. Overall, these results reinforce the potential of the dual-injection concept to provide a platform for aggressive downsizing, whilst contributing to a renewable energy economy.
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dual injection as a knock mitigation strategy using pure ethanol and methanol
SAE International Journal of Fuels and Lubricants, 2012Co-Authors: Ritchie Daniel, Chongming Wang, Guohong Tian, Dave RichardsonAbstract:For spark ignition (SI) engines, the optimum spark timing is crucial for maximum efficiency. However, as the spark timing is advanced, so the propensity to knock increases, thus compromising efficiency. One method to suppress knock is to use high Octane Fuel additives. However, the blend ratio of these additives cannot be varied on demand. Therefore, with the advent of aggressive downsizing, new knock mitigation techniques are required. Fortuitously, there are two well-known lower alcohols which exhibit attractive knock mitigation properties: ethanol and methanol. Both not only have high Octane ratings, but also result in greater charge-cooling than with gasoline. In the current work, the authors have exploited these attractive properties with the dual-injection, or the dual-Fuel concept (gasoline in PFI and Fuel additive in DI) using pure ethanol and methanol. The single cylinder engine results at 1500 rpm (λ=1) show benefits to indicated efficiency and emissions (HC, CO and CO2) at almost every load (4.5 bar to 8.5 bar IMEP) compared to GDI. This is because the spark timing can be significantly advanced despite the use of relatively low blends (≤50%, by volume), which lowers the combustion duration and improves the conversion of Fuel energy into useful work. Overall, these results reinforce the potential of the dual-injection concept to provide a platform for aggressive downsizing, whilst contributing to a renewable energy economy. Copyright © 2012 SAE International.
Hao Shi - One of the best experts on this subject based on the ideXlab platform.
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combustion stability study of partially premixed combustion by high pressure multiple injections with low Octane Fuel
Applied Energy, 2019Co-Authors: Qinglong Tang, Hao Shi, Jaeheon Sim, Junseok Chang, Gaetano Magnotti, Raman Vallinayagam, Bengt JohanssonAbstract:Abstract This work is the second part of a study on low-load combustion stability for gasoline partially premixed combustion. In part 1, we investigated the sensitivity of the intake air temperature to combustion stability. In part 2, we evaluate the potential of the multiple-injection strategy along with the intake air temperature sensitivity to promote low-load combustion stability using low-Octane gasoline Fuel. The experiments were carried out in a fully transparent, single-cylinder, compression-ignition engine. The spray/wall interaction, particularly the Fuel trapping in the piston crevice zone, was visualized by Fuel-tracer planar laser-induced fluorescence for the first time in experiments. The in-cylinder combustion process of natural flame luminosity was captured by a high-speed color camera. By employing a multiple-injection strategy, the minimum intake air temperature can be further reduced from 70 °C (single injection) to 50 °C for target stable combustion. The combustion stability and engine performance were further improved by increasing the Fuel injection pressure. For instance, with the triple-injection strategy at a higher Fuel-injection pressure of 800 bar, the indicated mean effective pressure was increased by 24% when compared to that of the single-injection strategy. A stronger interaction among Fuel spray jets, the piston, and the cylinder wall was observed for multiple injections with higher injection pressure, leading to higher unburned hydrocarbon (UHC) and carbon monoxide (CO) along with a more pronounced pool fire in the squish zone. The double-injection strategy resulted in lower UHC and CO emissions when compared to the triple-injection strategy. Applying a narrow spray angle injector with re-entrant combustion chamber is suggested for optimizing the spray/wall interaction.
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combustion stability study of partially premixed combustion with low Octane Fuel at low engine load conditions
Applied Energy, 2019Co-Authors: Vallinayagam Raman, Qinglong Tang, Hao Shi, Jaeheon Sim, Junseok Chang, Gaetano Magnotti, Bengt JohanssonAbstract:Abstract The study aims to investigate the sensitivity of combustion stability to the intake air temperature for partially premixed combustion (PPC). The experiments were carried out in a full view optical engine at low load condition. The ω shape optical piston crown as same as the actual product piston, rather than the flat crown piston used in the previous study, was employed for the present experimental test. The continuous-fire mode rather than the skip-fire mode was used to run the optical engine ensuring the similarity to the actual engine operating conditions. The interaction among Fuel spray jets, piston and cylinder wall was visualized by Fuel-tracer planar laser-induced fluorescence. The high-speed combustion images were processed to determine the combustion stratification based on the natural flame luminosity. The combustion phasing, maximum in-cylinder pressure, and indicated mean effective pressure (IMEP) were compared at various intake temperatures. The results showed that the lower intake temperature could be used for achieving better combustion stability at low load condition along with the retarded CA50, the lower maximum in-cylinder pressure, and the higher IMEP. 70 °C was the lower limit of intake temperature to achieve stable PPC operation with the single-injection strategy. The same trend of the combustion characteristics with respect to the start of injection timing was confirmed at various intake temperatures. The combustion stratification analysis indicated more inhomogeneous low-temperature combustion with decreased natural flame luminosity and increased soot emission when the intake temperature reduced from 120 °C to 70 °C. Nitrogen oxides emission decreased when compared to the higher intake temperature cases at the expense of increased unburned hydrocarbon and carbon monoxide emissions at PPC mode. The Fuel tracer measurements showed that most of the injected Fuel hit on the piston top and only less amount of Fuel was injected into the piston crown bowl at PPC mode due to the wider spray umbrella angle. The Fuel trapped in crevice zone was verified as an important source for the unburned hydrocarbon and carbon monoxide emissions at PPC mode. The injector dribbling during the late stage of combustion attributed to soot formation. The injector with a relatively narrow spray umbrella angle was suggested for optimized interaction among the Fuel spray jets, piston and the cylinder wall at PPC mode.
