A bi-fuel RCCI engine that uses a low reactivity renewable fuel like biogas along with diesel can decrease the NOx emissions and at the same time operate with high efficiency. Generally, diesel is injected in pulses, one very early and the other close to TDC. The early injection if done with conventional wide angle diesel injectors leads to wall wetting resulting in high THC, CO and adversely affects the efficiency. In this work a combination of injectors, one with a narrow angle between the sprays and the other with a wide angle between the sprays (NW Injectors) was evaluated for early and near TDC injections respectively in a biogas diesel RCCI engine. Simulations with a validated CFD model were used to determine the suitable injection parameters including the orientation of the spray holes, number of holes of the Narrow angle Injector (NI), fuel split ratio between narrow and wide injectors, injection timing and injection pressure. The studies indicated that the NI sprays have to hit the periphery of the piston bowl for good mixture preparation. The 3-hole NI configuration with the sprays aimed at the periphery of the piston bowl resulted in minimum fuel deposition, highest efficiency, and lowest soot and HC emissions. The NI was subsequently manufactured, installed on the engine and experiments were conducted in the biogas diesel NW RCCI mode for determining the performance and emissions and for comparing the same with the single Wide angle Injector RCCI (WI RCCI) mode in order to bring out its potential.
{"title":"Development and experimental validation of a novel twin injector concept for a biogas diesel RCCI engine","authors":"Gopa Kumar Sukumaran Nair, Akhil Balakrishnan, Asvathanarayanan Ramesh","doi":"10.1177/14680874241264337","DOIUrl":"https://doi.org/10.1177/14680874241264337","url":null,"abstract":"A bi-fuel RCCI engine that uses a low reactivity renewable fuel like biogas along with diesel can decrease the NOx emissions and at the same time operate with high efficiency. Generally, diesel is injected in pulses, one very early and the other close to TDC. The early injection if done with conventional wide angle diesel injectors leads to wall wetting resulting in high THC, CO and adversely affects the efficiency. In this work a combination of injectors, one with a narrow angle between the sprays and the other with a wide angle between the sprays (NW Injectors) was evaluated for early and near TDC injections respectively in a biogas diesel RCCI engine. Simulations with a validated CFD model were used to determine the suitable injection parameters including the orientation of the spray holes, number of holes of the Narrow angle Injector (NI), fuel split ratio between narrow and wide injectors, injection timing and injection pressure. The studies indicated that the NI sprays have to hit the periphery of the piston bowl for good mixture preparation. The 3-hole NI configuration with the sprays aimed at the periphery of the piston bowl resulted in minimum fuel deposition, highest efficiency, and lowest soot and HC emissions. The NI was subsequently manufactured, installed on the engine and experiments were conducted in the biogas diesel NW RCCI mode for determining the performance and emissions and for comparing the same with the single Wide angle Injector RCCI (WI RCCI) mode in order to bring out its potential.","PeriodicalId":14034,"journal":{"name":"International Journal of Engine Research","volume":"7 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The development of high-quality mixture is a critical requirement for achieving high-efficiency and low-emission diesel engines, and fuel injection system performance improvement and in-cylinder airflow organization are crucial ways for achieving high-quality mixture. The elliptical nozzle is used as the research object in this research, and numerical simulation is utilized to investigate the effect of different airflow speeds and directions on the atomization characteristics of the elliptical nozzle jet, in order to provide a theoretical basis for the engineering application of the elliptical nozzle in diesel engines. The results show that under the same airflow conditions, the vertical penetration distance of the spray decreases while the horizontal penetration distance increases with the use of elliptical orifices, the surface wave perturbation on the windward side is more violent, and reduce spray field the Sauter Mean Diameter (SMD). The spray projected area grew by 13.5%, the spray SMD dropped by 14.8%, and the vertical penetration distance of the spray with elliptical orifices fell by 18% with an increase in airflow velocity from 0 to 20 m/s. When the airflow direction and the spray direction were at a 90° angle and the SMD was lower than that of the circular orifice by 12.9%. The angle between the airflow direction and the short axis of the elliptical orifice was 30°when the spray projection area was larger, the perturbation of the spray body was more intense, and the surface wave amplitude was larger.
发展优质混合气是实现柴油发动机高效率和低排放的关键要求，而燃油喷射系统性能的提高和缸内气流组织是实现优质混合气的重要途径。本研究以椭圆喷嘴为研究对象，利用数值模拟研究了不同气流速度和方向对椭圆喷嘴射流雾化特性的影响，以期为椭圆喷嘴在柴油机中的工程应用提供理论依据。结果表明，在相同气流条件下，使用椭圆喷口后，喷雾的垂直穿透距离减小，而水平穿透距离增大，迎风面的表面波扰动更加剧烈，并减小了喷雾场的萨特平均直径（SMD）。当气流速度从 0 m/s 增加到 20 m/s 时，喷雾投影面积增加了 13.5%，喷雾 SMD 下降了 14.8%，使用椭圆形喷孔的喷雾垂直穿透距离下降了 18%。当气流方向与喷雾方向成 90° 角时，SMD 比圆形喷孔低 12.9%。气流方向与椭圆形喷口短轴的夹角为 30°时，喷射面积更大，喷射体的扰动更强烈，表面波振幅更大。
{"title":"Spray characteristics of elliptical orifice spray in diesel engine under air movement conditions","authors":"Hekun Jia, Xiangyu Cao, Bifeng Yin, Zhuangbang Wei","doi":"10.1177/14680874241261114","DOIUrl":"https://doi.org/10.1177/14680874241261114","url":null,"abstract":"The development of high-quality mixture is a critical requirement for achieving high-efficiency and low-emission diesel engines, and fuel injection system performance improvement and in-cylinder airflow organization are crucial ways for achieving high-quality mixture. The elliptical nozzle is used as the research object in this research, and numerical simulation is utilized to investigate the effect of different airflow speeds and directions on the atomization characteristics of the elliptical nozzle jet, in order to provide a theoretical basis for the engineering application of the elliptical nozzle in diesel engines. The results show that under the same airflow conditions, the vertical penetration distance of the spray decreases while the horizontal penetration distance increases with the use of elliptical orifices, the surface wave perturbation on the windward side is more violent, and reduce spray field the Sauter Mean Diameter (SMD). The spray projected area grew by 13.5%, the spray SMD dropped by 14.8%, and the vertical penetration distance of the spray with elliptical orifices fell by 18% with an increase in airflow velocity from 0 to 20 m/s. When the airflow direction and the spray direction were at a 90° angle and the SMD was lower than that of the circular orifice by 12.9%. The angle between the airflow direction and the short axis of the elliptical orifice was 30°when the spray projection area was larger, the perturbation of the spray body was more intense, and the surface wave amplitude was larger.","PeriodicalId":14034,"journal":{"name":"International Journal of Engine Research","volume":"7 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-25DOI: 10.1177/14680874241260363
Hideyuki Ogawa, Tomoki Ishikawa, Yoshimitsu Kobashi, Gen Shibata
The influence of spray-to-spray interaction after wall impingement of spray flames on the combustion characteristics in high pressure and high temperature ambient gas like in combustion chambers of diesel engines was examined with a constant volume vessel. Fuel was injected onto a flat wall from two nozzles to form two parallel, adjacent sprays in the vessel, causing the spray-to-spray interaction after the wall impingement. The combustion was analyzed with the rate of heat release calculated from the pressure transition in the vessel and the spray flame was visualized by high-speed video. The 310 nm UV light images of the chemiluminescence from OH radicals are recorded to demonstrate the reaction activity in the spray flame. The images of transmitted light throughout the constant volume vessel were recorded to visualize the soot formation and oxidation processes as well as to quantify the soot concentrations as the KL factors. The results showed that the rate of heat release from the main combustion decreases and the afterburning increases with the spray-to-spray interaction after the wall impingement of the spray flame. Combustion suppression with the spray-to-spray interaction occurred in all the conditions of the experiments here when changing the distance from the nozzle to the impinging wall between 25 and 40 mm and the fuel injection pressures between 100 and 200 MPa. Inside the spray-to-spray interaction zone, the chemiluminescence from OH radicals is weaker, supporting the inactive combustion due to difficulties of the air entrainment, and the lower transmitted light intensities with larger KL factors, indicating higher soot concentrations. The spray-to-spray interaction zone on the impingement wall advances toward the inside of the vessel between the sprays and it moves away from the wall, entraining the unutilized air and causing a relatively active combustion as well as rapid soot oxidation during the late afterburning stage.
{"title":"Influence of spray-to-spray interaction after wall impingement of spray flames on diesel combustion characteristics","authors":"Hideyuki Ogawa, Tomoki Ishikawa, Yoshimitsu Kobashi, Gen Shibata","doi":"10.1177/14680874241260363","DOIUrl":"https://doi.org/10.1177/14680874241260363","url":null,"abstract":"The influence of spray-to-spray interaction after wall impingement of spray flames on the combustion characteristics in high pressure and high temperature ambient gas like in combustion chambers of diesel engines was examined with a constant volume vessel. Fuel was injected onto a flat wall from two nozzles to form two parallel, adjacent sprays in the vessel, causing the spray-to-spray interaction after the wall impingement. The combustion was analyzed with the rate of heat release calculated from the pressure transition in the vessel and the spray flame was visualized by high-speed video. The 310 nm UV light images of the chemiluminescence from OH radicals are recorded to demonstrate the reaction activity in the spray flame. The images of transmitted light throughout the constant volume vessel were recorded to visualize the soot formation and oxidation processes as well as to quantify the soot concentrations as the KL factors. The results showed that the rate of heat release from the main combustion decreases and the afterburning increases with the spray-to-spray interaction after the wall impingement of the spray flame. Combustion suppression with the spray-to-spray interaction occurred in all the conditions of the experiments here when changing the distance from the nozzle to the impinging wall between 25 and 40 mm and the fuel injection pressures between 100 and 200 MPa. Inside the spray-to-spray interaction zone, the chemiluminescence from OH radicals is weaker, supporting the inactive combustion due to difficulties of the air entrainment, and the lower transmitted light intensities with larger KL factors, indicating higher soot concentrations. The spray-to-spray interaction zone on the impingement wall advances toward the inside of the vessel between the sprays and it moves away from the wall, entraining the unutilized air and causing a relatively active combustion as well as rapid soot oxidation during the late afterburning stage.","PeriodicalId":14034,"journal":{"name":"International Journal of Engine Research","volume":"424 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-25DOI: 10.1177/14680874241263193
Gen Shibata, Kensei Karumai, Suzune Sakai, Hideyuki Ogawa
In diesel engines, post fuel is injected in the expansion stroke, oxidized by the diesel oxidation catalysts and the high temperature gas re-generates the diesel particulate filters. However, it is empirically known that the post fuel at advanced injection timing is partially oxidized in the cylinder due to the high temperature-pressure conditions and it is a cause of the reduction of fuel consumption. The purpose of this research is to analyze post-injection fuel behaviors in cylinder and investigate the optimum fuel injections that maximize the unburnt hydrocarbons to the diesel oxidation catalysts. The engine employed in this research is a turbo charged 2.0 L four-cylinder DI diesel engine with two fuel injection systems to change the heterogeneity of air-fuel mixture and temperature distributions in cylinder; n-hexane is injected in the intake manifold to produce the homogeneous air-fuel mixture and diesel fuel is directly injected into the cylinder. The partial oxidation ratio of post fuel and the fuel loss mainly by fuel adhesion was calculated by injected fuel quantity, air quantity, and emission data. The 3D-CFD software was introduced to analyze the partial oxidation of post fuel and flow in the cylinder. The heterogeneity of burned gas mixture of post injection atmosphere and the post-injection timings were the parameters of engine tests and 3D-CFD simulations. The results suggest that the heterogeneity of equivalence ratio and the non-uniformity of gas temperature inside the cylinder at the start of post injection affect the partial oxidation of post-injection fuel. The more homogeneous these conditions are, the better the suppression of partial oxidation of post-injection fuel and the avoidance of fuel adhesion to the cylinder wall can be achieved.
在柴油发动机中，后燃油在膨胀冲程中喷射，被柴油氧化催化剂氧化，高温气体重新生成柴油微粒过滤器。然而，经验表明，在高温高压条件下，提前喷射正时的后燃油会在气缸内被部分氧化，这也是导致油耗降低的原因之一。本研究的目的是分析后喷射燃油在气缸中的行为，并研究最佳喷油量，以最大限度地将未燃烧的碳氢化合物喷入柴油氧化催化剂。本研究采用的发动机是一台涡轮增压 2.0 L 四缸 DI 柴油发动机，该发动机有两种燃油喷射系统，以改变气缸中空燃混合气的异质性和温度分布；正己烷喷射到进气歧管中以产生均匀的空燃混合气，柴油则直接喷射到气缸中。通过喷射燃料量、空气量和排放数据，计算了后燃料的部分氧化比和主要由燃料附着造成的燃料损失。引入 3D-CFD 软件分析后燃料的部分氧化和气缸内的流动。后喷射气氛中燃烧混合气体的异质性和后喷射时间是发动机试验和 3D-CFD 模拟的参数。结果表明，后喷射开始时等效比的异质性和气缸内气体温度的不均匀性会影响后喷射燃料的部分氧化。这些条件越均匀，就越能抑制后喷射燃料的部分氧化，避免燃料附着在气缸壁上。
{"title":"Study on partial oxidation phenomena of post-injection fuel in diesel engines","authors":"Gen Shibata, Kensei Karumai, Suzune Sakai, Hideyuki Ogawa","doi":"10.1177/14680874241263193","DOIUrl":"https://doi.org/10.1177/14680874241263193","url":null,"abstract":"In diesel engines, post fuel is injected in the expansion stroke, oxidized by the diesel oxidation catalysts and the high temperature gas re-generates the diesel particulate filters. However, it is empirically known that the post fuel at advanced injection timing is partially oxidized in the cylinder due to the high temperature-pressure conditions and it is a cause of the reduction of fuel consumption. The purpose of this research is to analyze post-injection fuel behaviors in cylinder and investigate the optimum fuel injections that maximize the unburnt hydrocarbons to the diesel oxidation catalysts. The engine employed in this research is a turbo charged 2.0 L four-cylinder DI diesel engine with two fuel injection systems to change the heterogeneity of air-fuel mixture and temperature distributions in cylinder; n-hexane is injected in the intake manifold to produce the homogeneous air-fuel mixture and diesel fuel is directly injected into the cylinder. The partial oxidation ratio of post fuel and the fuel loss mainly by fuel adhesion was calculated by injected fuel quantity, air quantity, and emission data. The 3D-CFD software was introduced to analyze the partial oxidation of post fuel and flow in the cylinder. The heterogeneity of burned gas mixture of post injection atmosphere and the post-injection timings were the parameters of engine tests and 3D-CFD simulations. The results suggest that the heterogeneity of equivalence ratio and the non-uniformity of gas temperature inside the cylinder at the start of post injection affect the partial oxidation of post-injection fuel. The more homogeneous these conditions are, the better the suppression of partial oxidation of post-injection fuel and the avoidance of fuel adhesion to the cylinder wall can be achieved.","PeriodicalId":14034,"journal":{"name":"International Journal of Engine Research","volume":"64 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-24DOI: 10.1177/14680874241261128
Mohamed Mohamed, Xinyan Wang, Hua Zhao, Jonathan Hall
The automotive industry must mitigate climate change by reducing vehicle carbon emissions and promoting sustainable transportation through technical solutions and innovations. Biofuels are seen as a solution to reduce CO2 emissions, but they may affect fuel performance and emissions. Second-generation biogasoline mixed with ethanol has proven that it can be introduced as a drop-in fuel with the same performance and tailpipe emissions at the same level as fossil fuels. However, particulate matter (PM) emissions are significantly higher than fossil fuels. This study aims to experimentally investigate the effect of port and direct fuel injections on the PM emissions in a boosted spark ignition (SI) engine fuelled by Euro 6 standard biofuel with a 99 octane number blended with 20% ethanol compared to a fossil fuel baseline. The single-cylinder SI engine was equipped with two fuel injectors, a direct injector and a port fuel injector, and operated with externally boosted air. The split injection ratio was adjusted from 100% direct injection (DI) to 100% port fuel injection (PFI) to investigate the combustion characteristics and particulate emissions (PM) at different engine loads and speeds. The results indicate that by changing 100% DI to 80% PFI, PM emissions numbers between particle sizes of 23 and 1000 nm were dropped by 96.56% at a low load operation of 4.6 bar IMEP for the 99 RON E20 biogasoline and by 84% for the 95 RON E10 fossil fuel while maintaining the same indicated thermal efficiency and a similar level of other emissions. However, at a higher load above 10 bar IMEP, it was found that full DI operation reduced particulate numbers (PN) by 64% and 38% for 99 RON E20 biogasoline and 95 RON E10 fossil fuel at 20 bar IMEP, respectively, and enabled more stable operation at 3000 rpm with higher load operation regions.
汽车行业必须通过技术解决方案和创新，减少汽车碳排放，促进可持续交通，从而减缓气候变化。生物燃料被视为减少二氧化碳排放的一种解决方案，但可能会影响燃料的性能和排放。事实证明，第二代生物汽油与乙醇混合后，可作为无须添加的燃料使用，其性能和尾气排放与化石燃料相同。然而，颗粒物（PM）排放量明显高于化石燃料。本研究的目的是通过实验研究端口喷射和直接喷射对增压火花点火（SI）发动机中颗粒物排放的影响，与化石燃料基线相比，该发动机使用的是辛烷值为 99、掺有 20% 乙醇的欧 6 标准生物燃料。单缸 SI 发动机配备了两个燃料喷射器（一个直接喷射器和一个端口燃料喷射器），使用外部增压空气运行。为了研究不同发动机负荷和转速下的燃烧特性和颗粒物排放（PM），将分体喷射比从 100% 直接喷射（DI）调整为 100% 端口喷射（PFI）。结果表明，将 100% DI 改为 80% PFI 后，在 4.6 巴 IMEP 的低负荷运行条件下，使用 99 RON E20 生物汽油时，粒径介于 23 纳米和 1000 纳米之间的 PM 排放量减少了 96.56%，使用 95 RON E10 化石燃料时减少了 84%，同时保持了相同的指示热效率和类似的其他排放水平。然而，在超过 10 巴 IMEP 的较高负荷下，全 DI 运行发现，在 20 巴 IMEP 下，99 RON E20 生物汽油和 95 RON E10 矿物燃料的颗粒数（PN）分别减少了 64% 和 38%，并在 3000 转/分钟的较高负荷运行区域实现了更稳定的运行。
{"title":"Effects of dual injection operations on combustion performances and particulate matter emissions in a spark ignition engine fuelled with second-generation biogasoline","authors":"Mohamed Mohamed, Xinyan Wang, Hua Zhao, Jonathan Hall","doi":"10.1177/14680874241261128","DOIUrl":"https://doi.org/10.1177/14680874241261128","url":null,"abstract":"The automotive industry must mitigate climate change by reducing vehicle carbon emissions and promoting sustainable transportation through technical solutions and innovations. Biofuels are seen as a solution to reduce CO<jats:sub>2</jats:sub> emissions, but they may affect fuel performance and emissions. Second-generation biogasoline mixed with ethanol has proven that it can be introduced as a drop-in fuel with the same performance and tailpipe emissions at the same level as fossil fuels. However, particulate matter (PM) emissions are significantly higher than fossil fuels. This study aims to experimentally investigate the effect of port and direct fuel injections on the PM emissions in a boosted spark ignition (SI) engine fuelled by Euro 6 standard biofuel with a 99 octane number blended with 20% ethanol compared to a fossil fuel baseline. The single-cylinder SI engine was equipped with two fuel injectors, a direct injector and a port fuel injector, and operated with externally boosted air. The split injection ratio was adjusted from 100% direct injection (DI) to 100% port fuel injection (PFI) to investigate the combustion characteristics and particulate emissions (PM) at different engine loads and speeds. The results indicate that by changing 100% DI to 80% PFI, PM emissions numbers between particle sizes of 23 and 1000 nm were dropped by 96.56% at a low load operation of 4.6 bar IMEP for the 99 RON E20 biogasoline and by 84% for the 95 RON E10 fossil fuel while maintaining the same indicated thermal efficiency and a similar level of other emissions. However, at a higher load above 10 bar IMEP, it was found that full DI operation reduced particulate numbers (PN) by 64% and 38% for 99 RON E20 biogasoline and 95 RON E10 fossil fuel at 20 bar IMEP, respectively, and enabled more stable operation at 3000 rpm with higher load operation regions.","PeriodicalId":14034,"journal":{"name":"International Journal of Engine Research","volume":"35 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As emissions regulations become more and more stringent and conventional fuel sources rarefaction, new alternatives are emerging to address this situation. Dual fuel engines are among the promising solutions, offering both ecological and economic advantages. However, these engines often confront constraints linked to high levels of unburnt hydrocarbons (HC) at low loads and NOx emissions at high loads. To overcome these problems and guarantee high-efficiency overall operating loads, exhaust gas recirculation (EGR) is a potential solution. In the present experimental study, appropriate modifications have been carried out to a single-cylinder diesel engine to ensure dual fuel operation with EGR. Natural gas and diesel are used as the primary and pilot fuel, respectively. At low load operations, the EGR rate is increased up to 35% until the reduction of unburnt hydrocarbons. However, at high loads, the EGR rate is carefully adjusted, as the combustion efficiency easily deteriorates due to oxygen amount lack in the combustion chamber. Also, minimizing NOx emissions is prioritized in all load conditions while keeping thermal efficiency in sight. In addition, the variation in the amount of pilot fuel is studied for improving the combination of dual fuel engine operation with the EGR technique. This made it possible to determine the influence of load, EGR rate, and pilot fuel quantity on the engine in response to the triple challenges of reducing NOx and HC and improving thermal efficiency. The results show that an adequate EGR rate of 30%, depending on the operating conditions, can reduce HC emissions by >25% while increasing thermal efficiency by around 20%. This result is accompanied by a significant reduction, over 90%, in NOx emissions.
{"title":"Toward improving efficiency and mitigating emissions in a natural gas/diesel direct injection dual fuel engine using EGR","authors":"Youcef Sehili, Lyes Tarabet, Mahfoudh Cerdoun, Khaled Loubar, Clément Lacroix","doi":"10.1177/14680874241261003","DOIUrl":"https://doi.org/10.1177/14680874241261003","url":null,"abstract":"As emissions regulations become more and more stringent and conventional fuel sources rarefaction, new alternatives are emerging to address this situation. Dual fuel engines are among the promising solutions, offering both ecological and economic advantages. However, these engines often confront constraints linked to high levels of unburnt hydrocarbons (HC) at low loads and NO<jats:sub>x</jats:sub> emissions at high loads. To overcome these problems and guarantee high-efficiency overall operating loads, exhaust gas recirculation (EGR) is a potential solution. In the present experimental study, appropriate modifications have been carried out to a single-cylinder diesel engine to ensure dual fuel operation with EGR. Natural gas and diesel are used as the primary and pilot fuel, respectively. At low load operations, the EGR rate is increased up to 35% until the reduction of unburnt hydrocarbons. However, at high loads, the EGR rate is carefully adjusted, as the combustion efficiency easily deteriorates due to oxygen amount lack in the combustion chamber. Also, minimizing NO<jats:sub>x</jats:sub> emissions is prioritized in all load conditions while keeping thermal efficiency in sight. In addition, the variation in the amount of pilot fuel is studied for improving the combination of dual fuel engine operation with the EGR technique. This made it possible to determine the influence of load, EGR rate, and pilot fuel quantity on the engine in response to the triple challenges of reducing NO<jats:sub>x</jats:sub> and HC and improving thermal efficiency. The results show that an adequate EGR rate of 30%, depending on the operating conditions, can reduce HC emissions by >25% while increasing thermal efficiency by around 20%. This result is accompanied by a significant reduction, over 90%, in NO<jats:sub>x</jats:sub> emissions.","PeriodicalId":14034,"journal":{"name":"International Journal of Engine Research","volume":"46 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A multi-layer membrane has been fabricated to integrate a Three-Way Catalyst (TWC) and Gasoline Particulate Filter (GPF) into one device, called a four-way catalytic converter. The top layer, made of nano-scale potassium catalyst particles, traps Particulate Matter (PM) with almost 100% filtration efficiency at all times and oxidizes PM (mostly soot) with a significantly reduced temperature of 476°C at the oxidation peak. Moreover, the bottom layer catalyst is comprised of sub-micro TWC particles to combine NO reduction and CO oxidation capabilities. The effective temperature range for the simultaneous removal of all pollutants was between 420°C–500°C.
{"title":"A multi-layer membrane filter made of potassium catalyst and three-way catalyst for a passive after-treatment system","authors":"Teerapat Suteerapongpun, Masaru Ogura, Katsunori Hanamura","doi":"10.1177/14680874241261106","DOIUrl":"https://doi.org/10.1177/14680874241261106","url":null,"abstract":"A multi-layer membrane has been fabricated to integrate a Three-Way Catalyst (TWC) and Gasoline Particulate Filter (GPF) into one device, called a four-way catalytic converter. The top layer, made of nano-scale potassium catalyst particles, traps Particulate Matter (PM) with almost 100% filtration efficiency at all times and oxidizes PM (mostly soot) with a significantly reduced temperature of 476°C at the oxidation peak. Moreover, the bottom layer catalyst is comprised of sub-micro TWC particles to combine NO reduction and CO oxidation capabilities. The effective temperature range for the simultaneous removal of all pollutants was between 420°C–500°C.","PeriodicalId":14034,"journal":{"name":"International Journal of Engine Research","volume":"82 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-24DOI: 10.1177/14680874241261101
Benjamín Pla, Pedro Piqueras, Pau Bares, André Nakaema Aronis
The purpose of this study is to enhance control strategies for selective catalytic reduction (SCR) and ammonia slip catalyst (ASC) systems, aiming to effectively reduce NOx emissions from automotive engines during realistic driving cycles. Despite the effectiveness of these after-treatment systems (ATS), their dynamic and non-linear characteristics present significant challenges in achieving precise control. Therefore, this research proposes a hybrid approach that combines backward induction (BI) as the primary optimization technique with model predictive control (MPC) framework for real-time application. The article introduces a reduced-state control-oriented model of the SCR + ASC system, which is embedded into the BI algorithm to calculate optimal control actions within a finite horizon. Additionally, it is proposed an alternative approach for adapting the grid of model states within the BI algorithm, effectively reducing the computational cost. This adjustment enables the algorithm to operate in real-time with near-optimal results, as confirmed by experimental validation. Lastly, the study explores how different degrees of knowledge regarding system disturbances impact the strategy’s performance, examining three distinct scenarios: constant prediction horizon, probabilistic description, and full knowledge of the prediction horizon.
本研究旨在加强选择性催化还原（SCR）和氨滑移催化剂（ASC）系统的控制策略，以有效减少汽车发动机在实际驾驶循环中的氮氧化物排放。尽管这些后处理系统（ATS）效果显著，但其动态和非线性特性给实现精确控制带来了巨大挑战。因此，本研究提出了一种混合方法，将作为主要优化技术的后向感应（BI）与实时应用的模型预测控制（MPC）框架相结合。文章介绍了 SCR + ASC 系统的简化状态控制导向模型，并将其嵌入 BI 算法，以计算有限范围内的最优控制操作。此外，文章还提出了一种在 BI 算法中调整模型状态网格的替代方法，从而有效降低了计算成本。实验验证证实，这种调整可使算法以接近最优的结果实时运行。最后，该研究探讨了不同程度的系统干扰知识对该策略性能的影响，研究了三种不同的情况：恒定预测范围、概率描述和预测范围的完全知识。
{"title":"SCR + ASC systems control by backward induction with adaptive grid and different disturbance scenarios","authors":"Benjamín Pla, Pedro Piqueras, Pau Bares, André Nakaema Aronis","doi":"10.1177/14680874241261101","DOIUrl":"https://doi.org/10.1177/14680874241261101","url":null,"abstract":"The purpose of this study is to enhance control strategies for selective catalytic reduction (SCR) and ammonia slip catalyst (ASC) systems, aiming to effectively reduce NOx emissions from automotive engines during realistic driving cycles. Despite the effectiveness of these after-treatment systems (ATS), their dynamic and non-linear characteristics present significant challenges in achieving precise control. Therefore, this research proposes a hybrid approach that combines backward induction (BI) as the primary optimization technique with model predictive control (MPC) framework for real-time application. The article introduces a reduced-state control-oriented model of the SCR + ASC system, which is embedded into the BI algorithm to calculate optimal control actions within a finite horizon. Additionally, it is proposed an alternative approach for adapting the grid of model states within the BI algorithm, effectively reducing the computational cost. This adjustment enables the algorithm to operate in real-time with near-optimal results, as confirmed by experimental validation. Lastly, the study explores how different degrees of knowledge regarding system disturbances impact the strategy’s performance, examining three distinct scenarios: constant prediction horizon, probabilistic description, and full knowledge of the prediction horizon.","PeriodicalId":14034,"journal":{"name":"International Journal of Engine Research","volume":"28 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-24DOI: 10.1177/14680874241258533
John Gandolfo, Benjamin Lawler, Brian Gainey
Direct injection fuel systems provide precise control over the amount of fuel injected and can enable higher compression ratio operation and earlier combustion phasing under knock-limited operation, particularly for fuels with a high cooling potential like hydrous ethanol, a blend of 92% ethanol and 8% water. Moving a portion of the total fuel mass from an intake stroke injection to a compression stroke injection can provide a knock suppression benefit, which can enable more efficient operation. In this work, the influence of injection pressure on this split injection spark ignition strategy is examined. The effect of injection pressure on two intake stroke injections were characterized, with an injection pressure of 200 bar improving combustion efficiency by ∼3 percentage points and advancing knock-limited CA50 by 1 crank angle degree over an injection pressure of 30 bar. Then, a compression stroke injection was introduced and swept into the compression stroke while maintaining the two intake stroke injections. Direct injections at an injection pressure of 30 bar enabled a small knock intensity reduction of ∼20%, whereas an injection pressure of 200 bar enabled a larger reduction of ∼90% in knock intensity. The spark timing advance permitted by the reduction in knock intensity with a compression stroke injection timing of −80 degrees after top dead center was 0.3 and 2.0 degrees at an injection pressure of 30 and 200 bar, respectively. Then, the second intake stroke injection was varied at 200 bar to evaluate how the stratification profile prior to the compression stroke injection impacted its ability to reduce knock intensity. It was found that compression stroke injections with an early second intake stroke injection was effective at reducing knock intensity throughout the compression stroke. As the second intake stroke injection was retarded, the early compression stroke injections became less effective at suppressing knock.
{"title":"Effect of injection timings and injection pressure on knock mitigation with a compression stroke injection of hydrous ethanol in spark ignition","authors":"John Gandolfo, Benjamin Lawler, Brian Gainey","doi":"10.1177/14680874241258533","DOIUrl":"https://doi.org/10.1177/14680874241258533","url":null,"abstract":"Direct injection fuel systems provide precise control over the amount of fuel injected and can enable higher compression ratio operation and earlier combustion phasing under knock-limited operation, particularly for fuels with a high cooling potential like hydrous ethanol, a blend of 92% ethanol and 8% water. Moving a portion of the total fuel mass from an intake stroke injection to a compression stroke injection can provide a knock suppression benefit, which can enable more efficient operation. In this work, the influence of injection pressure on this split injection spark ignition strategy is examined. The effect of injection pressure on two intake stroke injections were characterized, with an injection pressure of 200 bar improving combustion efficiency by ∼3 percentage points and advancing knock-limited CA50 by 1 crank angle degree over an injection pressure of 30 bar. Then, a compression stroke injection was introduced and swept into the compression stroke while maintaining the two intake stroke injections. Direct injections at an injection pressure of 30 bar enabled a small knock intensity reduction of ∼20%, whereas an injection pressure of 200 bar enabled a larger reduction of ∼90% in knock intensity. The spark timing advance permitted by the reduction in knock intensity with a compression stroke injection timing of −80 degrees after top dead center was 0.3 and 2.0 degrees at an injection pressure of 30 and 200 bar, respectively. Then, the second intake stroke injection was varied at 200 bar to evaluate how the stratification profile prior to the compression stroke injection impacted its ability to reduce knock intensity. It was found that compression stroke injections with an early second intake stroke injection was effective at reducing knock intensity throughout the compression stroke. As the second intake stroke injection was retarded, the early compression stroke injections became less effective at suppressing knock.","PeriodicalId":14034,"journal":{"name":"International Journal of Engine Research","volume":"39 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pre-chamber jet ignition is a key technology for future high-efficiency natural gas (NG) engines. It can achieve fast and stable combustion through excellent ignition performance. However, there are still some challenges, such as high combustion instability near the lean burn limit and the narrow engine operating range. Therefore, this paper investigates the combustion instability of a pre-chamber NG engine under ultra-diluted conditions by experimental method. At two engine loads, experiments are carried out with different jet ignition intensity schemes to study the effect of jet ignition intensity on the cyclic combustion variations. Then, the combustion instability characteristics of the pre-chamber NG engine are studied by cyclic variation analysis and phase space reconstruction. The results show that with the increase in the jet ignition intensity, the cyclic combustion variations decrease, and the cyclic variation coefficient of the indicated mean effective pressure decreases to below 2%. The lean burn limit of the pre-chamber natural gas engine is extended to an excess air ratio of 2.0. The operation instability of the pre-chamber NG engine is mainly due to cyclic variations in the ignition and combustion process. The nonlinear dynamic analysis shows that the combustion process in the lean burn pre-chamber NG engine behaves with chaotic characteristics under the operating conditions of low jet ignition intensity. As the jet ignition intensity increases, the combustion stability is improved and the cycle-to-cycle variations change from fairly deterministic to more stochastic behavior. The chaotic characteristics of the combustion process become weaker. In conclusion, it is of great importance to generate stable and high ignition intensity jets for reducing combustion instability and improving combustion efficiency in lean burn pre-chamber NG engines.
前腔喷射点火是未来高效天然气（NG）发动机的一项关键技术。它可以通过出色的点火性能实现快速稳定的燃烧。然而，该技术仍面临一些挑战，如接近贫燃极限时燃烧不稳定性较高以及发动机工作范围较窄等。因此，本文通过实验方法研究了超稀释条件下前室 NG 发动机的燃烧不稳定性。在两种发动机负荷下，采用不同的喷气点火强度方案进行实验，研究喷气点火强度对循环燃烧变化的影响。然后，通过循环变化分析和相空间重构研究了前室 NG 发动机的燃烧不稳定性特征。结果表明，随着射流点火强度的增加，循环燃烧变化减小，指示平均有效压力的循环变化系数减小到 2% 以下。前置腔天然气发动机的贫燃极限扩大到过量空气比 2.0。前室天然气发动机运行不稳定的主要原因是点火和燃烧过程的周期性变化。非线性动力学分析表明，在喷气点火强度较低的运行条件下，贫燃前室天然气发动机的燃烧过程表现出混沌特性。随着喷气点火强度的增加，燃烧稳定性得到改善，周期与周期之间的变化从相当确定的行为转变为更多的随机行为。燃烧过程的混沌特性变得越来越弱。总之，产生稳定的高点火强度射流对于降低燃烧不稳定性和提高贫燃前室 NG 发动机的燃烧效率具有重要意义。
{"title":"Experimental study on combustion instability characteristics in a pre-chamber natural gas engine under lean burn conditions","authors":"Xue Yang, Guanguan Li, Yong Cheng, Pengcheng Wang, Yanlei Zhao","doi":"10.1177/14680874241254882","DOIUrl":"https://doi.org/10.1177/14680874241254882","url":null,"abstract":"Pre-chamber jet ignition is a key technology for future high-efficiency natural gas (NG) engines. It can achieve fast and stable combustion through excellent ignition performance. However, there are still some challenges, such as high combustion instability near the lean burn limit and the narrow engine operating range. Therefore, this paper investigates the combustion instability of a pre-chamber NG engine under ultra-diluted conditions by experimental method. At two engine loads, experiments are carried out with different jet ignition intensity schemes to study the effect of jet ignition intensity on the cyclic combustion variations. Then, the combustion instability characteristics of the pre-chamber NG engine are studied by cyclic variation analysis and phase space reconstruction. The results show that with the increase in the jet ignition intensity, the cyclic combustion variations decrease, and the cyclic variation coefficient of the indicated mean effective pressure decreases to below 2%. The lean burn limit of the pre-chamber natural gas engine is extended to an excess air ratio of 2.0. The operation instability of the pre-chamber NG engine is mainly due to cyclic variations in the ignition and combustion process. The nonlinear dynamic analysis shows that the combustion process in the lean burn pre-chamber NG engine behaves with chaotic characteristics under the operating conditions of low jet ignition intensity. As the jet ignition intensity increases, the combustion stability is improved and the cycle-to-cycle variations change from fairly deterministic to more stochastic behavior. The chaotic characteristics of the combustion process become weaker. In conclusion, it is of great importance to generate stable and high ignition intensity jets for reducing combustion instability and improving combustion efficiency in lean burn pre-chamber NG engines.","PeriodicalId":14034,"journal":{"name":"International Journal of Engine Research","volume":"14 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141780780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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