Shuaijia Huang, Tie Li, Chongmin Wu, Bin Wang, M. Zheng
Ultra-lean burn with high turbulence has high potential for improving thermal efficiency and reducing NOx emissions in spark-ignition engines. Formation of initial flame kernel in high-turbulence flow by advanced ignition technologies is crucial for successful implementation of the ultra-lean burn concept. In this study, a four-coil ignition system is designed to enable temporally flexible discharge, including the single strike, multi-strike and continuous discharge with the discharge energy range from 100 to 300 mJ. The performance of the different discharge strategies on igniting the lean methane-air mixture is evaluated in an optically accessible constant volume vessel. The initial mixture pressure of 3.0 MPa and temperature of 388 K are set to simulate typical conditions near TDC (top dead center) of turbocharged large-bore natural gas engines. Both the flow and quiescent conditions around the spark plug are taken into account with and without gas flows in the vessel. The flame kernel formation and developing processes are captured by using the Schlieren imaging technique with a high-speed CMOS video camera, while evolution of both the voltage and current in the circuit are well monitored by the high-voltage probe and current clamp. With the continuous discharge ignition, the lean limit is remarkably extended in the case of the flow condition, while it is changed only slightly under the quiescent condition, compared with the other strategies. Analysis of the current and voltage waveforms shows that the continuous discharge strategy can enable a steadier and longer discharging period than the other strategies, regardless of conditions with and without gas flow. Besides, the continuous discharge strategy can accelerate the initial flame propagation compared with the other strategies. Once the flame kernel is successfully established, an increase in the discharge energy of single strike has no obvious effects on the flame development, but it is necessary for maintaining the lean limit. Although, in principle, the multi-strike discharge strategy can increase the ignition energy released to the mixture, the current waveform is prone to be interrupted with the discharge channel strongly distorted by the gas flow under the high-pressure condition. The flame propagation speed of the ultra-lean mixture is rather slow under the high ambient pressure quiescent condition compared with the high ambient pressure flow condition. Enhancement of turbulent flow in the mixture is very crucial for realizing the highly efficient and stable combustion of the lean mixture.
{"title":"Effects of Various Discharge Strategies on Ignition of Lean Methane/Air Mixture","authors":"Shuaijia Huang, Tie Li, Chongmin Wu, Bin Wang, M. Zheng","doi":"10.1115/ICEF2018-9648","DOIUrl":"https://doi.org/10.1115/ICEF2018-9648","url":null,"abstract":"Ultra-lean burn with high turbulence has high potential for improving thermal efficiency and reducing NOx emissions in spark-ignition engines. Formation of initial flame kernel in high-turbulence flow by advanced ignition technologies is crucial for successful implementation of the ultra-lean burn concept.\u0000 In this study, a four-coil ignition system is designed to enable temporally flexible discharge, including the single strike, multi-strike and continuous discharge with the discharge energy range from 100 to 300 mJ. The performance of the different discharge strategies on igniting the lean methane-air mixture is evaluated in an optically accessible constant volume vessel. The initial mixture pressure of 3.0 MPa and temperature of 388 K are set to simulate typical conditions near TDC (top dead center) of turbocharged large-bore natural gas engines. Both the flow and quiescent conditions around the spark plug are taken into account with and without gas flows in the vessel. The flame kernel formation and developing processes are captured by using the Schlieren imaging technique with a high-speed CMOS video camera, while evolution of both the voltage and current in the circuit are well monitored by the high-voltage probe and current clamp.\u0000 With the continuous discharge ignition, the lean limit is remarkably extended in the case of the flow condition, while it is changed only slightly under the quiescent condition, compared with the other strategies. Analysis of the current and voltage waveforms shows that the continuous discharge strategy can enable a steadier and longer discharging period than the other strategies, regardless of conditions with and without gas flow. Besides, the continuous discharge strategy can accelerate the initial flame propagation compared with the other strategies. Once the flame kernel is successfully established, an increase in the discharge energy of single strike has no obvious effects on the flame development, but it is necessary for maintaining the lean limit. Although, in principle, the multi-strike discharge strategy can increase the ignition energy released to the mixture, the current waveform is prone to be interrupted with the discharge channel strongly distorted by the gas flow under the high-pressure condition. The flame propagation speed of the ultra-lean mixture is rather slow under the high ambient pressure quiescent condition compared with the high ambient pressure flow condition. Enhancement of turbulent flow in the mixture is very crucial for realizing the highly efficient and stable combustion of the lean mixture.","PeriodicalId":441369,"journal":{"name":"Volume 1: Large Bore Engines; Fuels; Advanced Combustion","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122719413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Saif Salih, D. DelVescovo, Christopher P. Kolodziej, T. Rockstroh, Alexander Hoth
In order to establish a pathway to evaluate chemical kinetic mechanisms (detailed or reduced) in a real engine environment, a GT Power model of the well-studied Cooperative Fuels Research (CFR) engine was developed and validated against experimental data for primary reference fuel blends between 60 and 100 under RON conditions. The CFR engine model utilizes a predictive turbulent flame propagation sub-model, and implements a chemical kinetic solver to solve the end-gas chemistry. The validation processes were performed simultaneously for thermodynamic and chemical kinetic parameters to match IVC conditions, burn rate, and knock prediction. A recently published kinetic mechanism was implemented in GT-Power, and was found to over-predict the low temperature heat release for iso-octane and PRF blends, leading to advanced knock onset phasing compared to experiments. Three reaction rates in the iso-octane and n-heptane pathways were tuned in the kinetic mechanism in order to match experimental knock-point values, yielding excellent agreement in terms of the knock onset phasing, burn rate, and the thermodynamic conditions compared to experiments. This developed model provides the initial/boundary conditions of the CFR engine under RON conditions, including IVC temperature and pressure, MFB profile, residual fraction and composition. The conditions were then correlated as a function of CFR engine compression ratio, and implemented in a 0-D SI engine model in Chemkin Pro in order to demonstrate an application of the current work. The Chemkin Pro and GT-Power simulations provided nearly identical results despite significant differences in heat transfer models and chemical kinetic solvers. This work provides the necessary framework by which robust chemical kinetic mechanisms can be developed, evaluated, and tuned, based on the knocking tendencies in a real engine environment for PRF blends.
{"title":"Defining the Boundary Conditions of the CFR Engine Under RON Conditions for Knock Prediction and Robust Chemical Mechanism Validation","authors":"Saif Salih, D. DelVescovo, Christopher P. Kolodziej, T. Rockstroh, Alexander Hoth","doi":"10.1115/ICEF2018-9640","DOIUrl":"https://doi.org/10.1115/ICEF2018-9640","url":null,"abstract":"In order to establish a pathway to evaluate chemical kinetic mechanisms (detailed or reduced) in a real engine environment, a GT Power model of the well-studied Cooperative Fuels Research (CFR) engine was developed and validated against experimental data for primary reference fuel blends between 60 and 100 under RON conditions. The CFR engine model utilizes a predictive turbulent flame propagation sub-model, and implements a chemical kinetic solver to solve the end-gas chemistry. The validation processes were performed simultaneously for thermodynamic and chemical kinetic parameters to match IVC conditions, burn rate, and knock prediction. A recently published kinetic mechanism was implemented in GT-Power, and was found to over-predict the low temperature heat release for iso-octane and PRF blends, leading to advanced knock onset phasing compared to experiments. Three reaction rates in the iso-octane and n-heptane pathways were tuned in the kinetic mechanism in order to match experimental knock-point values, yielding excellent agreement in terms of the knock onset phasing, burn rate, and the thermodynamic conditions compared to experiments. This developed model provides the initial/boundary conditions of the CFR engine under RON conditions, including IVC temperature and pressure, MFB profile, residual fraction and composition. The conditions were then correlated as a function of CFR engine compression ratio, and implemented in a 0-D SI engine model in Chemkin Pro in order to demonstrate an application of the current work. The Chemkin Pro and GT-Power simulations provided nearly identical results despite significant differences in heat transfer models and chemical kinetic solvers. This work provides the necessary framework by which robust chemical kinetic mechanisms can be developed, evaluated, and tuned, based on the knocking tendencies in a real engine environment for PRF blends.","PeriodicalId":441369,"journal":{"name":"Volume 1: Large Bore Engines; Fuels; Advanced Combustion","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125422343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Heavy-duty compression-ignition (CI) engines converted to natural gas (NG) spark ignition (SI) operation have the potential to increase the use of NG in the transportation sector. A 3D numerical simulation was used to predict how the conventional CI combustion chamber geometry (i.e., re-entrant bowl and flat head) affects the combustion stability, performance and emissions of a single-cylinder CI engine that was converted to SI operation by adding a low-pressure gas injector in the intake manifold and a spark plug in place of the diesel injector. The G-equation based 3D CFD simulation investigated three different combustion chamber configurations that changes the size of the squish region at constant compression ratio and clearance height. The results show that the different flame propagation speeds inside and outside the re-entrant bowl can create a two-zone combustion phenomenon. More, a larger squish region increased flame burning speed, which decreased late-combustion duration. All these findings support the need for further investigations of combustion chamber shape design for optimum engine performance and emissions in CI engines converted to NG SI operation.
{"title":"Numerical Simulation of Re-Entrant Bowl Effects on Natural Gas SI Operation","authors":"Jinlong Liu, C. Dumitrescu","doi":"10.1115/ICEF2018-9609","DOIUrl":"https://doi.org/10.1115/ICEF2018-9609","url":null,"abstract":"Heavy-duty compression-ignition (CI) engines converted to natural gas (NG) spark ignition (SI) operation have the potential to increase the use of NG in the transportation sector. A 3D numerical simulation was used to predict how the conventional CI combustion chamber geometry (i.e., re-entrant bowl and flat head) affects the combustion stability, performance and emissions of a single-cylinder CI engine that was converted to SI operation by adding a low-pressure gas injector in the intake manifold and a spark plug in place of the diesel injector. The G-equation based 3D CFD simulation investigated three different combustion chamber configurations that changes the size of the squish region at constant compression ratio and clearance height. The results show that the different flame propagation speeds inside and outside the re-entrant bowl can create a two-zone combustion phenomenon. More, a larger squish region increased flame burning speed, which decreased late-combustion duration. All these findings support the need for further investigations of combustion chamber shape design for optimum engine performance and emissions in CI engines converted to NG SI operation.","PeriodicalId":441369,"journal":{"name":"Volume 1: Large Bore Engines; Fuels; Advanced Combustion","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116237516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Malin, Christoph Redtenbacher, Gottfried Lurf, N. Wermuth, A. Wimmer
The balancing of the electric grid has become more challenging due to the expansion of fluctuating renewable energy sources for electric power generation. The importance of power plants driven by internal combustion engines will increase since they can react flexibly and quickly to changes in the energy demand. With regard to the emission of pollutants and CO2, gas fueled engines are favored for gensets. However, it is more challenging to meet the dynamic load requirements with a gas engine than with a conventional diesel engine because the load acceptance of the gas engine is limited by the occurrence of knocking combustion. Dual fuel engines are a good compromise between these two engine concepts; they can use gaseous fuel during steady state engine operation and increase the diesel share during transient modes to improve the dynamic behavior. The high number of degrees of freedom of dual fuel combustion concepts requires advanced operating strategies. The aim of this paper is to investigate and evaluate strategies to improve the transient behavior of a 20-cylinder large bore diesel-gas engine (displacement 6.24 dm3 per cylinder) for a genset application. In the investigations, the latest turbocharging technology is applied in combination with a turbine waste gate. A wide range diesel injector that covers the whole diesel injection range of approximately 1 % to 100 % diesel fraction1 of the rated power fuel mass provides the basis for the most flexible diesel injection. A 1D simulation tool was used to model and optimize the genset in transient operation. The combustion process was simulated with Vibe heat release rate models. The optimized transient engine operating strategies were validated on a highly dynamic single cylinder research engine test bed. The paper provides a comparison of different strategies that use these technologies to improve the dynamic behavior of the genset in island mode operation during a 50 % load step. Key to meeting the challenging requirements is an optimized diesel injection strategy or even a switch from gas operation mode to diesel operation mode during the load step. Based on the results of simulation and engine testing, potential ways to minimize engine speed drop and recovery time after the load demand increase are evaluated.
{"title":"Evaluation of Strategies for Highly Transient Operation of Diesel-Gas Engines","authors":"M. Malin, Christoph Redtenbacher, Gottfried Lurf, N. Wermuth, A. Wimmer","doi":"10.1115/ICEF2018-9710","DOIUrl":"https://doi.org/10.1115/ICEF2018-9710","url":null,"abstract":"The balancing of the electric grid has become more challenging due to the expansion of fluctuating renewable energy sources for electric power generation. The importance of power plants driven by internal combustion engines will increase since they can react flexibly and quickly to changes in the energy demand. With regard to the emission of pollutants and CO2, gas fueled engines are favored for gensets. However, it is more challenging to meet the dynamic load requirements with a gas engine than with a conventional diesel engine because the load acceptance of the gas engine is limited by the occurrence of knocking combustion.\u0000 Dual fuel engines are a good compromise between these two engine concepts; they can use gaseous fuel during steady state engine operation and increase the diesel share during transient modes to improve the dynamic behavior. The high number of degrees of freedom of dual fuel combustion concepts requires advanced operating strategies.\u0000 The aim of this paper is to investigate and evaluate strategies to improve the transient behavior of a 20-cylinder large bore diesel-gas engine (displacement 6.24 dm3 per cylinder) for a genset application. In the investigations, the latest turbocharging technology is applied in combination with a turbine waste gate. A wide range diesel injector that covers the whole diesel injection range of approximately 1 % to 100 % diesel fraction1 of the rated power fuel mass provides the basis for the most flexible diesel injection. A 1D simulation tool was used to model and optimize the genset in transient operation. The combustion process was simulated with Vibe heat release rate models. The optimized transient engine operating strategies were validated on a highly dynamic single cylinder research engine test bed.\u0000 The paper provides a comparison of different strategies that use these technologies to improve the dynamic behavior of the genset in island mode operation during a 50 % load step. Key to meeting the challenging requirements is an optimized diesel injection strategy or even a switch from gas operation mode to diesel operation mode during the load step. Based on the results of simulation and engine testing, potential ways to minimize engine speed drop and recovery time after the load demand increase are evaluated.","PeriodicalId":441369,"journal":{"name":"Volume 1: Large Bore Engines; Fuels; Advanced Combustion","volume":"43 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131215439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Mairegger, R. Herdin, L. Konstantinoff, Lukas Möltner
Turbocharged gas engines for combined heat and power units are optimized to increase efficiency while observing and maintaining legitimate exhaust gas emissions. In order to do so, the charge motion is raised. This study investigates the influence of passive prechamber spark plugs in high turbulent combustion chambers. The subjects of investigation are two different gas engine types, one of them running on sewage gas the other one on biogas. The occurring charge motions initiated by the cylinder heads are measured by integrative determination of swirl motion on a flow bench. In addition, three different passive prechamber spark plugs are characterized by a combustion analysis. Each of the three spark plugs comes with a different electrode or prechamber geometry. The resulting combustion and operating conditions are compared while the equal brake mean effective pressure and constant NOx-emissions are sustained. The results of the combustion analysis show a rising influence of the spark plug with increasing air-to-fuel-ratio induced by charge motion. Furthermore, clear differences between the spark plugs are determined: electrode arrangement and prechamber geometry help to influence lean misfire limits, engine smoothness, start behavior and ignition delay. The results indicate the capability of spark plugs to increase lifetime and engine efficiency.
{"title":"Optimization of Electrode Arrangement and Prechamber Geometry of Passive Prechamber Spark Plugs for Turbocharged Gas Engines With High Charge Motion","authors":"D. Mairegger, R. Herdin, L. Konstantinoff, Lukas Möltner","doi":"10.1115/ICEF2018-9628","DOIUrl":"https://doi.org/10.1115/ICEF2018-9628","url":null,"abstract":"Turbocharged gas engines for combined heat and power units are optimized to increase efficiency while observing and maintaining legitimate exhaust gas emissions. In order to do so, the charge motion is raised. This study investigates the influence of passive prechamber spark plugs in high turbulent combustion chambers. The subjects of investigation are two different gas engine types, one of them running on sewage gas the other one on biogas. The occurring charge motions initiated by the cylinder heads are measured by integrative determination of swirl motion on a flow bench. In addition, three different passive prechamber spark plugs are characterized by a combustion analysis. Each of the three spark plugs comes with a different electrode or prechamber geometry. The resulting combustion and operating conditions are compared while the equal brake mean effective pressure and constant NOx-emissions are sustained. The results of the combustion analysis show a rising influence of the spark plug with increasing air-to-fuel-ratio induced by charge motion. Furthermore, clear differences between the spark plugs are determined: electrode arrangement and prechamber geometry help to influence lean misfire limits, engine smoothness, start behavior and ignition delay. The results indicate the capability of spark plugs to increase lifetime and engine efficiency.","PeriodicalId":441369,"journal":{"name":"Volume 1: Large Bore Engines; Fuels; Advanced Combustion","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133103509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiangyu Meng, Wuqiang Long, Yihui Zhou, Mingshu Bi, C. Lee
Because of the potential to reduce NOx and PM emissions simultaneously and the utilization of biofuel, diesel/compressed natural gas (CNG) dual-fuel combustion mode with port injection of CNG and direct injection of diesel has been widely studied. While in comparison with conventional diesel combustion mode, the dual-fuel combustion mode generally leads lower thermal efficiency, especially at low and medium load, and higher carbon monoxide (CO) and total hydrocarbons (THC) emissions. In this work, n-butanol was blended with diesel as the pilot fuel to explore the possibility to improve the performance and emissions of dual-fuel combustion mode with CNG. Various pilot fuels of B0 (pure diesel), B10 (90% diesel/10% n-butanol by volume basis), B20 (80% diesel/20% n-butanol) and B30 (70% diesel/30% n-butanol) were compared at the CNG substitution rate of 70% by energy basis under the engine speeds of 1400 and 1800 rpm. The experiments were carried out by sweeping a wide range of pilot fuel start of injection timings based on the same total input energy including pilot fuel and CNG. As n-butanol was added into the pilot fuel, the pilot fuel/CNG/air mixture tends to be more homogeneous. The results showed that for the engine speed of 1400 rpm, pilot fuel with n-butanol addition leads to a slightly lower indicated thermal efficiency (ITE). B30 reveals much lower NOx emission and slightly higher THC emissions. For the engine speed of 1800 rpm, B20 can improve ITE and decrease the NOx and THC emissions simultaneously relative to B0.
{"title":"Effects of N-Butanol Content on the Dual-Fuel Combustion Mode With CNG at Two Engine Speeds","authors":"Xiangyu Meng, Wuqiang Long, Yihui Zhou, Mingshu Bi, C. Lee","doi":"10.1115/ICEF2018-9595","DOIUrl":"https://doi.org/10.1115/ICEF2018-9595","url":null,"abstract":"Because of the potential to reduce NOx and PM emissions simultaneously and the utilization of biofuel, diesel/compressed natural gas (CNG) dual-fuel combustion mode with port injection of CNG and direct injection of diesel has been widely studied. While in comparison with conventional diesel combustion mode, the dual-fuel combustion mode generally leads lower thermal efficiency, especially at low and medium load, and higher carbon monoxide (CO) and total hydrocarbons (THC) emissions. In this work, n-butanol was blended with diesel as the pilot fuel to explore the possibility to improve the performance and emissions of dual-fuel combustion mode with CNG. Various pilot fuels of B0 (pure diesel), B10 (90% diesel/10% n-butanol by volume basis), B20 (80% diesel/20% n-butanol) and B30 (70% diesel/30% n-butanol) were compared at the CNG substitution rate of 70% by energy basis under the engine speeds of 1400 and 1800 rpm. The experiments were carried out by sweeping a wide range of pilot fuel start of injection timings based on the same total input energy including pilot fuel and CNG. As n-butanol was added into the pilot fuel, the pilot fuel/CNG/air mixture tends to be more homogeneous. The results showed that for the engine speed of 1400 rpm, pilot fuel with n-butanol addition leads to a slightly lower indicated thermal efficiency (ITE). B30 reveals much lower NOx emission and slightly higher THC emissions. For the engine speed of 1800 rpm, B20 can improve ITE and decrease the NOx and THC emissions simultaneously relative to B0.","PeriodicalId":441369,"journal":{"name":"Volume 1: Large Bore Engines; Fuels; Advanced Combustion","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114904950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Paras Sethi, Eric Passow, K. Karrip, Max Maschewske, Jason Bieneman, Paul Truckel
There are many articles and papers published about the developments in engine downsizing as an effective means in reducing vehicle fuel consumption while improving engine performance. The increase in performance of gasoline turbo charged direct injected (GTDI) engines, in conjunction with diverse vehicle platform performance targets (i.e. towing capability) and higher gear transmissions pushes the engine to operate with higher torques at lower engine speeds. This operating condition has increased the propensity of an abnormal combustion event, known as Low Speed Pre-Ignition (LSPI) or Stochastic Pre-Ignition (SPI). The power cylinder unit (PCU) components exposed to this pre-ignition event can experience failure. The engine manufacturers, as well as MAHLE, continue to ensure engine and PCU component survivability against LSPI by performing life cycle robustness testing. MAHLE’s research of LSPI continues to focus on the robustness of PCU components in the presence of LSPI events, as well as investigating design developments that have the potential to minimize the propensity of LSPI to occur. The test procedure development for evaluating natural LSPI events will be presented. Various test results and parameter sensitivities that were documented during this procedure development, along with the many challenges associated with engine performance repeatability will be discussed. Parameters that were found to influence LSPI propensity, as well as parameters that were found not to influence LSPI propensity will be discussed.
{"title":"A Study to Determine Factors That Have Influence on the Propensity of Natural LSPI Occurring in GTDI Engines","authors":"Paras Sethi, Eric Passow, K. Karrip, Max Maschewske, Jason Bieneman, Paul Truckel","doi":"10.1115/ICEF2018-9760","DOIUrl":"https://doi.org/10.1115/ICEF2018-9760","url":null,"abstract":"There are many articles and papers published about the developments in engine downsizing as an effective means in reducing vehicle fuel consumption while improving engine performance. The increase in performance of gasoline turbo charged direct injected (GTDI) engines, in conjunction with diverse vehicle platform performance targets (i.e. towing capability) and higher gear transmissions pushes the engine to operate with higher torques at lower engine speeds. This operating condition has increased the propensity of an abnormal combustion event, known as Low Speed Pre-Ignition (LSPI) or Stochastic Pre-Ignition (SPI). The power cylinder unit (PCU) components exposed to this pre-ignition event can experience failure. The engine manufacturers, as well as MAHLE, continue to ensure engine and PCU component survivability against LSPI by performing life cycle robustness testing. MAHLE’s research of LSPI continues to focus on the robustness of PCU components in the presence of LSPI events, as well as investigating design developments that have the potential to minimize the propensity of LSPI to occur. The test procedure development for evaluating natural LSPI events will be presented. Various test results and parameter sensitivities that were documented during this procedure development, along with the many challenges associated with engine performance repeatability will be discussed. Parameters that were found to influence LSPI propensity, as well as parameters that were found not to influence LSPI propensity will be discussed.","PeriodicalId":441369,"journal":{"name":"Volume 1: Large Bore Engines; Fuels; Advanced Combustion","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116432222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gasoline compression ignition (GCI) using a single gasoline-type fuel for port fuel and direct injection has been shown as a method to achieve low-temperature combustion with low engine-out NOx and soot emissions and high indicated thermal efficiency. However, key technical barriers to achieving low temperature combustion on multi-cylinder engines include the air handling system (limited amount of exhaust gas recirculation (EGR)) as well as mechanical engine limitations (e.g. peak pressure rise rate). In light of these limitations, high temperature combustion with reduced amounts of EGR appears more practical. Furthermore, for high temperature GCI, an effective aftertreatment system allows high thermal efficiency with low tailpipe-out emissions. In this work, experimental testing was conducted on a 12.4 L multi-cylinder heavy-duty diesel engine operating with high temperature GCI combustion using EEE gasoline. Engine testing was conducted at an engine speed of 1038 rpm and brake mean effective pressure (BMEP) of 14 bar. Port fuel and direct injection strategies were utilized to increase the premixed combustion fraction. The impact on engine performance and emissions with respect to varying the injection and intake operating parameters was quantified within this study. A combined effect of reducing heat transfer and increasing exhaust loss resulted in a flat trend of brake thermal efficiency (BTE) when retarding direct injection timing, while increased port fuel mass improved BTE due to advanced combustion phasing and reduced heat transfer loss. Overall, varying intake valve close timing, EGR, intake pressure and temperature with the current pressure rise rate and soot emissions constraint was not effective in improving BTE, as the benefit of low heat transfer loss was always offset by increased exhaust loss.
{"title":"Effects of Port Fuel and Direct Injection Strategies and Intake Conditions on Gasoline Compression Ignition Operation","authors":"Buyu Wang, Michael Pamminger, T. Wallner","doi":"10.1115/ICEF2018-9723","DOIUrl":"https://doi.org/10.1115/ICEF2018-9723","url":null,"abstract":"Gasoline compression ignition (GCI) using a single gasoline-type fuel for port fuel and direct injection has been shown as a method to achieve low-temperature combustion with low engine-out NOx and soot emissions and high indicated thermal efficiency. However, key technical barriers to achieving low temperature combustion on multi-cylinder engines include the air handling system (limited amount of exhaust gas recirculation (EGR)) as well as mechanical engine limitations (e.g. peak pressure rise rate). In light of these limitations, high temperature combustion with reduced amounts of EGR appears more practical. Furthermore, for high temperature GCI, an effective aftertreatment system allows high thermal efficiency with low tailpipe-out emissions. In this work, experimental testing was conducted on a 12.4 L multi-cylinder heavy-duty diesel engine operating with high temperature GCI combustion using EEE gasoline. Engine testing was conducted at an engine speed of 1038 rpm and brake mean effective pressure (BMEP) of 14 bar. Port fuel and direct injection strategies were utilized to increase the premixed combustion fraction. The impact on engine performance and emissions with respect to varying the injection and intake operating parameters was quantified within this study. A combined effect of reducing heat transfer and increasing exhaust loss resulted in a flat trend of brake thermal efficiency (BTE) when retarding direct injection timing, while increased port fuel mass improved BTE due to advanced combustion phasing and reduced heat transfer loss. Overall, varying intake valve close timing, EGR, intake pressure and temperature with the current pressure rise rate and soot emissions constraint was not effective in improving BTE, as the benefit of low heat transfer loss was always offset by increased exhaust loss.","PeriodicalId":441369,"journal":{"name":"Volume 1: Large Bore Engines; Fuels; Advanced Combustion","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123390257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Detection of combustion related phenomena such as misfire, knock and sporadic preignition is very important for the development of electronic controls needed for the gasoline direct injection engines to meet the production goals in power, fuel economy, and low emissions. This paper applies several types of combustion ionization sensors, and a pressure transducer that directly sense the in-cylinder combustion, and the knock sensor which is an accelerometer that detects the impact of combustion on engine structure vibration. Experimental investigations were conducted on a turbocharged four cylinders gasoline direct injection engine under operating conditions that produce the above phenomena. One of the cylinders is instrumented with a Piezo quartz pressure transducer, MSFI (Multi sensing fuel injector), a standalone ion current probe, and a spark plug applied to act as an ion current sensor. A comparison is made between the capabilities of the pressure transducer, ion current sensors, and the knock sensor in detecting the above phenomena. The signals from in-cylinder combustion sensors give more accurate information about combustion than the knock sensor. As far as the feasibility and cost of their application in production vehicles the spark plug sensor and MSFI appear to be the most favorable, followed by the Standalone mounted sensor which is an addition to the engine.
{"title":"Combustion Ionization for Detection of Misfire, Knock, and Sporadic Pre-Ignition in a Gasoline Direct Injection Engine","authors":"Samuel Ayad, Swapnil Sharma, R. Verma, N. Henein","doi":"10.1115/ICEF2018-9589","DOIUrl":"https://doi.org/10.1115/ICEF2018-9589","url":null,"abstract":"Detection of combustion related phenomena such as misfire, knock and sporadic preignition is very important for the development of electronic controls needed for the gasoline direct injection engines to meet the production goals in power, fuel economy, and low emissions.\u0000 This paper applies several types of combustion ionization sensors, and a pressure transducer that directly sense the in-cylinder combustion, and the knock sensor which is an accelerometer that detects the impact of combustion on engine structure vibration. Experimental investigations were conducted on a turbocharged four cylinders gasoline direct injection engine under operating conditions that produce the above phenomena. One of the cylinders is instrumented with a Piezo quartz pressure transducer, MSFI (Multi sensing fuel injector), a standalone ion current probe, and a spark plug applied to act as an ion current sensor. A comparison is made between the capabilities of the pressure transducer, ion current sensors, and the knock sensor in detecting the above phenomena. The signals from in-cylinder combustion sensors give more accurate information about combustion than the knock sensor. As far as the feasibility and cost of their application in production vehicles the spark plug sensor and MSFI appear to be the most favorable, followed by the Standalone mounted sensor which is an addition to the engine.","PeriodicalId":441369,"journal":{"name":"Volume 1: Large Bore Engines; Fuels; Advanced Combustion","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127720430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pistons for heavy duty diesel applications endure high thermal loads and therefore result in reduced durability. Pistons for such heavy duty applications are generally designed with an internal oil gallery — called the piston cooling gallery (PCG) — where the intent is to reduce the piston crown temperatures through forced convection cooling and thereby ensure the durability of the piston. One of the key factors influencing the efficiency of such a heat-transfer process is the volume fraction of oil inside the piston cooling gallery — defined as the filling ratio (FR) — during engine operation. As a part of this study, a motoring engine measurement system was developed to measure the piston filling ratio of an inline-6 production heavy duty engine. In this system, multiple high precision pressure sensors were applied to the piston cooling gallery and a linkage was designed and fabricated to transfer the piston cooling gallery oil pressure signal out of the motoring engine. This pressure information was then correlated with the oil filling ratio through a series of calibration runs with known oil quantity in the piston cooling gallery. This proposed method can be used to measure the piston cooling gallery oil filling ratio for heavy duty engine pistons. A preliminary transient Computational Fluid Dynamics (CFD) analysis was performed to identify the filling ratio and transient pressures at the corresponding transducer locations in the piston cooling gallery for one of the motoring test operating speeds (1200 RPM). A mesh dependency study was performed for the CFD analysis and the results were compared against those from the motoring test.
{"title":"Heavy Duty Engine Piston Cooling Gallery Oil Filling Ratio Measurement and Comparison of Results With Simulation","authors":"Yu Chen, Shashank S. Moghe","doi":"10.1115/ICEF2018-9582","DOIUrl":"https://doi.org/10.1115/ICEF2018-9582","url":null,"abstract":"Pistons for heavy duty diesel applications endure high thermal loads and therefore result in reduced durability. Pistons for such heavy duty applications are generally designed with an internal oil gallery — called the piston cooling gallery (PCG) — where the intent is to reduce the piston crown temperatures through forced convection cooling and thereby ensure the durability of the piston. One of the key factors influencing the efficiency of such a heat-transfer process is the volume fraction of oil inside the piston cooling gallery — defined as the filling ratio (FR) — during engine operation.\u0000 As a part of this study, a motoring engine measurement system was developed to measure the piston filling ratio of an inline-6 production heavy duty engine. In this system, multiple high precision pressure sensors were applied to the piston cooling gallery and a linkage was designed and fabricated to transfer the piston cooling gallery oil pressure signal out of the motoring engine. This pressure information was then correlated with the oil filling ratio through a series of calibration runs with known oil quantity in the piston cooling gallery. This proposed method can be used to measure the piston cooling gallery oil filling ratio for heavy duty engine pistons. A preliminary transient Computational Fluid Dynamics (CFD) analysis was performed to identify the filling ratio and transient pressures at the corresponding transducer locations in the piston cooling gallery for one of the motoring test operating speeds (1200 RPM). A mesh dependency study was performed for the CFD analysis and the results were compared against those from the motoring test.","PeriodicalId":441369,"journal":{"name":"Volume 1: Large Bore Engines; Fuels; Advanced Combustion","volume":"239 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115969711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：