The Experts below are selected from a list of 12243 Experts worldwide ranked by ideXlab platform
Volker Sick - One of the best experts on this subject based on the ideXlab platform.
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three dimensional spray flow interaction in a spark ignition Direct Injection Engine
International Journal of Engine Research, 2016Co-Authors: Hao Chen, Peter M Lillo, Volker SickAbstract:Large efforts are currently being made toward improving internal combustion Engine efficiency without degrading overall performance. To this end, advanced combustion strategies that require in-cyli...
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Spray-induced temperature stratification dynamics in a gasoline Direct-Injection Engine
Proceedings of the Combustion Institute, 2015Co-Authors: Brian Peterson, Volker Sick, Elias Baum, Benjamin Böhm, Andreas DreizlerAbstract:Abstract Simultaneous applications of high-speed toluene-LIF thermometry and PIV at kHz rates were utilized to investigate the evolution of gas temperature stratification imposed from Direct-Injection of liquid fuel within a motored SIDI Engine. Temperature imaging was based on the two-color detection method that measures the LIF signal ratio from two separated wavelength ranges to enable LIF temperature imaging within inhomogeneously mixed systems. It was observed that cold gases associated with evaporative cooling exist within the regions of dense liquid fuel droplet clouds. As droplets disperse, the cold-gas regions expand and relative temperatures as low as −50 K exist. Average temperature gradients between cold- and bulk-gases are up to 30 K/mm and gradients persist but drop in magnitude throughout compression as cold- and bulk-gases mix. Temperature stratification is greatest as the fuel disperses within the field-of-view producing large areas of cold-gases with relative temperatures as low as −50 K. Individual temperature images and 2D PDFs of identified cold-gas regions reveal that local regions of cold-gas imposed from evaporative cooling can last up to 30 CAD after fuel Injection for the given operating conditions. The time-resolved imaging study show the mechanics of localized evaporative cooling and bulk-flow motion-driven mixing that over time reduces temperature gradients but does not completely homogenize the temperature fields.
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analysis of misfires in a Direct Injection Engine using proper orthogonal decomposition
Experiments in Fluids, 2011Co-Authors: Hao Chen, David L Reuss, Volker SickAbstract:Previous work demonstrated that the occasional misfired and partially burned cycles (MF) in a stratified-charge, spark-ignited Direct Injection Engine always achieved an early flame kernel, but failed to reach and inflame the fuel in the bottom of the piston bowl. This conclusion was derived from intra-cycle crank angle resolved velocity and fuel concentration images that were recorded simultaneously using high-speed particle image velocimetry and planar laser-induced fluorescence. In this study, both ensemble average analysis, conditionally sampled on either MF or Well Burned (WB) cycles and proper orthogonal decomposition (POD) are applied separately to the velocity and fuel distributions. POD of the velocity and fuel distributions near the spark plug were performed, and the mode energy and structure of the modes are compared. This analysis is used to assess the similarity and differences between the MF and the WB cycles and to identify physical insight gained by POD. The POD modes were determined from the combined set of 200 WB and 37 MF cycles to create two sets of 237 orthogonal modes, one set for the velocity, V, and one for the equivalence ratio, e. Then, conditionally sampled averages of the POD coefficients could be used to quantify the extent to which each mode contributed to the MFs. Also, the probability density functions of the coefficients quantified the cyclic variability of each mode’s contribution. The application of proper orthogonal decomposition to velocity and equivalence ratio images was useful in identifying and analyzing the differences in flow and mixture conditions at the time of spark between well-burning and misfiring cycles. However, POD results alone were not sufficient to identify which of the cycles were misfiring cycles, and additional information was required for conditional sampling.
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high speed imaging analysis of misfires in a spray guided Direct Injection Engine
Proceedings of the Combustion Institute, 2011Co-Authors: Brian Peterson, David L Reuss, Volker SickAbstract:Abstract This study is an experimental investigation of rare misfire and partial burn cycles in a spray-guided spark-ignited Direct-Injection optical Engine. Spark discharge energy, discharge duration, flame imaging, velocity and equivalence ratio were measured every crank angle degree. Imaging was performed using high-speed 2-D particle image velocimetry (PIV) and planar laser inducted fluorescence (PLIF). The Engine was operated near its optimum but produced rare and random partial burn and misfire cycles. Spark energy and spark duration for the partial burn and misfire cycles fell within the range of those for the well-burned cycles, with a slight bias toward low-energy, short-duration discharges, indicating no abnormal spark discharge events. PIV and PLIF measurements extracted from a 4 mm × 4 mm region adjacent to and downstream of the spark plug at spark timing revealed that the partial burn and misfire cycles occur under lean mixtures and low velocities, but still within the range of values for the well-burned cycles. PIV and PLIF images of partial burn and misfire cycles were compared to well-burned cycles, which had similar velocities and equivalence ratios near the spark plug at the onset of spark. Observations of the fuel distribution and flame areas for the partial burns and misfires showed that an early flame kernel was always formed, but failed to develop sufficiently to propagate to the fuel in the bowl. A flame kernel arriving late within the piston bowl found significantly leaner conditions and the mixture was not fully consumed leading to a partial burn. For misfire cycles, the mixture in the measurement plane was significantly leaner surrounding the flame kernel, which disappeared shortly after the spark discharge. It is concluded that the partial burns and misfires are not the result of failed ignition, but failure during the flame propagation process.
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Laser Combustion Diagnostics, Application to Engines
Laser Applilcations to Chemical Security and Environmental Analysis, 2006Co-Authors: Volker Sick, James D. SmithAbstract:Laser-induced fluorescence of biacetyl is used to measure the temporal evolution of fuel distributions at rates of 12 kHz in a gasoline Direct-Injection Engine with a frequency-tripled diode-pumped Nd:YAG laser and an image-intensified CMOS camera.
Brian Peterson - One of the best experts on this subject based on the ideXlab platform.
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Spray-induced temperature stratification dynamics in a gasoline Direct-Injection Engine
Proceedings of the Combustion Institute, 2015Co-Authors: Brian Peterson, Volker Sick, Elias Baum, Benjamin Böhm, Andreas DreizlerAbstract:Abstract Simultaneous applications of high-speed toluene-LIF thermometry and PIV at kHz rates were utilized to investigate the evolution of gas temperature stratification imposed from Direct-Injection of liquid fuel within a motored SIDI Engine. Temperature imaging was based on the two-color detection method that measures the LIF signal ratio from two separated wavelength ranges to enable LIF temperature imaging within inhomogeneously mixed systems. It was observed that cold gases associated with evaporative cooling exist within the regions of dense liquid fuel droplet clouds. As droplets disperse, the cold-gas regions expand and relative temperatures as low as −50 K exist. Average temperature gradients between cold- and bulk-gases are up to 30 K/mm and gradients persist but drop in magnitude throughout compression as cold- and bulk-gases mix. Temperature stratification is greatest as the fuel disperses within the field-of-view producing large areas of cold-gases with relative temperatures as low as −50 K. Individual temperature images and 2D PDFs of identified cold-gas regions reveal that local regions of cold-gas imposed from evaporative cooling can last up to 30 CAD after fuel Injection for the given operating conditions. The time-resolved imaging study show the mechanics of localized evaporative cooling and bulk-flow motion-driven mixing that over time reduces temperature gradients but does not completely homogenize the temperature fields.
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high speed imaging analysis of misfires in a spray guided Direct Injection Engine
Proceedings of the Combustion Institute, 2011Co-Authors: Brian Peterson, David L Reuss, Volker SickAbstract:Abstract This study is an experimental investigation of rare misfire and partial burn cycles in a spray-guided spark-ignited Direct-Injection optical Engine. Spark discharge energy, discharge duration, flame imaging, velocity and equivalence ratio were measured every crank angle degree. Imaging was performed using high-speed 2-D particle image velocimetry (PIV) and planar laser inducted fluorescence (PLIF). The Engine was operated near its optimum but produced rare and random partial burn and misfire cycles. Spark energy and spark duration for the partial burn and misfire cycles fell within the range of those for the well-burned cycles, with a slight bias toward low-energy, short-duration discharges, indicating no abnormal spark discharge events. PIV and PLIF measurements extracted from a 4 mm × 4 mm region adjacent to and downstream of the spark plug at spark timing revealed that the partial burn and misfire cycles occur under lean mixtures and low velocities, but still within the range of values for the well-burned cycles. PIV and PLIF images of partial burn and misfire cycles were compared to well-burned cycles, which had similar velocities and equivalence ratios near the spark plug at the onset of spark. Observations of the fuel distribution and flame areas for the partial burns and misfires showed that an early flame kernel was always formed, but failed to develop sufficiently to propagate to the fuel in the bowl. A flame kernel arriving late within the piston bowl found significantly leaner conditions and the mixture was not fully consumed leading to a partial burn. For misfire cycles, the mixture in the measurement plane was significantly leaner surrounding the flame kernel, which disappeared shortly after the spark discharge. It is concluded that the partial burns and misfires are not the result of failed ignition, but failure during the flame propagation process.
Yangbing Zeng - One of the best experts on this subject based on the ideXlab platform.
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COLD-START CFD SIMULATION OF SPARK-IGNITION Direct-Injection Engine
Journal of Engineering for Gas Turbines and Power, 2018Co-Authors: Xiaofeng Yang, Tang-wei Kuo, Kulwinder Singh, Rafat Hattar, Yangbing ZengAbstract:Reliably starting the Engine during extremely cold ambient temperatures is one of the largest calibration and emissions challenges in Engine development. Although cold-start conditions comprise only a small portion of an Engine's typical drive cycle, large amounts of hydrocarbon and particulate emissions are generated during this time, and the calibration of cold-start operation takes several months to complete. During the cold start period, results of previous cycle combustion event strongly influences the subsequent cycle due to variations in Engine speed, residual fraction, residual wall film mass, in-cylinder charge and wall temperatures, and air flow distribution between cylinders. Including all these parameters in computational fluid dynamics (CFD) simulation is critical in understanding the cold start process in transient and cumulative manner. Measured cold start data of a production of four-cylinder spark-ignition (SI) Direct-Injection Engine were collected for this study with an ambient temperature of −30 °C. Three-dimensional (3D) transient Engine flow, spray, and combustion simulation over first three consecutive Engine cycles is carried out to provide a better understanding of the cold-start process. Measured Engine speed and one-dimensional (1D) conjugate heat transfer (CHT) model is used to capture realistic in-cylinder flow dynamics and transient wall temperatures for more accurate fuel–air mixing predictions. The CFD predicted cumulative heat release trend for the first three cycles matches the data from measured pressure analysis. The same observation can be made for the vaporized fuel mass as well. These observations are explained in the report.
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Cold-Start CFD Simulation of Spark-Ignition Direct-Injection Engine
Volume 2: Emissions Control Systems; Instrumentation Controls and Hybrids; Numerical Simulation; Engine Design and Mechanical Development, 2017Co-Authors: Xiaofeng Yang, Tang-wei Kuo, Kulwinder Singh, Rafat Hattar, Yangbing ZengAbstract:Reliably starting the Engine during extremely cold ambient temperatures is one of the largest calibration and emissions challenges in Engine development. Although cold-start conditions comprise only a small portion of an Engine’s typical drive cycle, large amounts of hydrocarbon and particulate emissions are generated during this time, and the calibration of cold-start operation takes several months to complete. During the cold start period, results of previous cycle combustion event strongly influences the subsequent cycle due to variations in Engine speed, residual fraction, residual wall film mass, in-cylinder charge and wall temperatures, and air flow distribution between cylinders. Include all these parameters in CFD simulation is critical in understanding the cold start process in transient and cumulative manner. Measured cold start data of a production four cylinder spark-ignition Direct-Injection Engine was collected for this study with an ambient temperature of −30 °C. Three-dimensional transient Engine flow, spray and combustion simulation over first 3 consecutive Engine cycles is carried out to provide a better understandings of the cold-start process. Measured Engine speed and 1D conjugate heat transfer model are used to capture realistic in-cylinder flow dynamics and transient wall temperatures for more accurate fuel-air mixing predictions. The CFD predicted cumulative heat release trend for the first 3 cycles matches the data from measured pressure analysis. The same observation can be made for the vaporized fuel mass as well. These observations are explained in the report.
Bin Chen - One of the best experts on this subject based on the ideXlab platform.
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An investigation on the effect of intake air humidification on the thermal balance of a turbocharged gasoline Direct Injection Engine
Case Studies in Thermal Engineering, 2020Co-Authors: Bin Chen, Li Zhang, Jinlin HanAbstract:Abstract This study analyzed the thermal balance of a turbocharged gasoline Direct Injection Engine with intake air humidification and studied the reason why intake air humidification improved the thermal efficiency of the basic Engine. The results showed that since the evaporation of the introduced water absorbed heat in the intake port that caused the decrease of the temperature of the intake air, and the specific heat capacity of working medium increased with intake air humidification. Therefore, an apparent decrease in the in-cylinder temperature. Each energy loss can be affected by intake air humidification in different degrees, among which the exhaust loss and heat transfer loss decreased evidently, while pumping loss and friction loss increased to some extent. Furthermore, the sum of the decrease of exhaust loss and heat transfer loss was higher than the sum of the increase of pumping loss and friction loss, hence, the thermal efficiency of the basic gasoline Engine increased when the benefit gained from intake air humidification was greater than the negative impact.
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Investigating Effects of Water Injection on Availabilities of a Turbocharged Gasoline Direct Injection Engine
Journal of Energy Engineering, 2019Co-Authors: Bin Chen, Li Zhang, Xi Chen, Qing ZhangAbstract:AbstractWater Injection in gasoline Engines is an effective technique for controlling Engine knock and reducing NOx emissions. By adding water, the changes in the specific heat capacity and the int...
Yonggyu Lee - One of the best experts on this subject based on the ideXlab platform.
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Lower particulate matter emissions with a stoichiometric LPG Direct Injection Engine
Fuel, 2017Co-Authors: Keunsoo Kim, Jung Hwan Kim, Changup Kim, Yonggyu LeeAbstract:Abstract The Direct Injection (DI) Engine is considered as a promising technology that can improve fuel economy compared to the conventional port fuel Injection Engine. However, studies have shown that relatively high levels of particulate matter (PM) are emitted by gasoline fuel Engines. This is a concern in view of more stringent emission regulations expected in the future. In this respect, the use of Liquefied Petroleum Gas (LPG) in Direct Injection Engines has the following advantages: (1) lower carbon dioxide (CO 2 ) emissions due to its low carbon content; and (2) reduced PM emission because it is a premixed mixture. This study used an LPG Direct Injection Engine that was converted from a 2000-cm 3 , 4-cylinder gasoline port fuel Injection (PFI) Engine. The Engine head was redesigned for the spray-guided Direct Injection combustion system. The conventional LPG for transportation in South Korea was used as the fuel, and the Engine was operated under stoichiometric condition. In this study, the Engine operation map that covers the entire operating envelope was provided to investigate its particle number concentrations and exhaust emissions, including total hydrocarbon (THC), carbon monoxide (CO), carbon dioxide (CO 2 ) and nitrogen oxides (NO x ) as a function of Engine operating points. Also, the particle number size distribution was shown as a function of Engine operating conditions. The results of this study indicated that a lower occurrence of THC and NO x emissions compared to previous gasoline studies. The main finding in this study was that particulate matter emissions of a LPG Direct Injection Engine were substantially lower than those from a gasoline Direct Injection Engine.