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Yasuhiro Urata - One of the best experts on this subject based on the ideXlab platform.
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flame chemiluminescence studies of cyclic combustion variations and air to fuel Ratio of the reacting mixture in a lean burn stratified charge spark ignition engine
Combustion and Flame, 2004Co-Authors: P G Aleiferis, Y Hardalupas, A M K P Taylor, Kazuo Ishii, Yasuhiro UrataAbstract:The operating range of lean-burn spark-ignition engines is limited by the level of cyclic variability in the early flame development that typically corresponds to the 0-5% mass fraction burned duRation. An experimental investigation was undertaken to study the levels of flame chemiluminescence in an optical stratified-charge spark-ignition engine, using a Cassegrain optical system with high spatial resolution. Measurements of OH and CH-radical intensities were simultaneously acquired with double flame images per cycle for a range of Air-to-Fuel Ratios (A/F=12-22). These signals of chemiluminescence were used to evaluate the in-cylinder equivalence Ratio of the reacting mixture and to further examine its contribution to the flame growth speed and the cyclic variability in the crank angle by which 5% mass fraction was burned (θXb5%). Specifically, the Ratio of the OH/CH chemiluminescence signals was calibrated in the engine and tested extensively for different injection strategies and spark advances, to measure the "global" and "local" in-cylinder A/F Ratio around the spark plug. The complications encountered towards this goal are discussed in detail. The results showed that the equivalence Ratio exhibited large variations on a cycle-by-cycle basis and consistently produced negative correlation coefficients with θXb5%, especially for lean-set operating conditions (A/F=20-22). Particularly, for open-valve injection strategy that yielded a stratified mixture, the degree of this correlation lied in the range ≈-0.4 to -0.8, being lower for the locally measured A/F Ratio and higher for the globally evaluated one. Some issues related to the opposite gradients of the calibRation curves deduced for the measurement of the global and local in-cylinder A/F Ratios need to be examined outside the engine using a combustion facility with controlled conditions of pressure, temperature, turbulence intensity, and dilution by combustion residuals. © 2003 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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flame chemiluminescence studies of cyclic combustion variations and air to fuel Ratio of the reacting mixture in a lean burn stratified charge spark ignition engine
Combustion and Flame, 2004Co-Authors: P G Aleiferis, Y Hardalupas, Kazuo Ishii, A M K P Taylo, Yasuhiro UrataAbstract:The operating range of lean-burn spark-ignition engines is limited by the level of cyclic variability in the early flame development that typically corresponds to the 0-5% mass fraction burned duRation. An experimental investigation was undertaken to study the levels of flame chemiluminescence in an optical stratified-charge spark-ignition engine, using a Cassegrain optical system with high spatial resolution. Measurements of OH and CH-radical intensities were simultaneously acquired with double flame images per cycle for a range of Air-to-Fuel Ratios (A/F=12-22). These signals of chemiluminescence were used to evaluate the in-cylinder equivalence Ratio of the reacting mixture and to further examine its contribution to the flame growth speed and the cyclic variability in the crank angle by which 5% mass fraction was burned (θXb5%). Specifically, the Ratio of the OH/CH chemiluminescence signals was calibrated in the engine and tested extensively for different injection strategies and spark advances, to measure the "global" and "local" in-cylinder A/F Ratio around the spark plug. The complications encountered towards this goal are discussed in detail. The results showed that the equivalence Ratio exhibited large variations on a cycle-by-cycle basis and consistently produced negative correlation coefficients with θXb5%, especially for lean-set operating conditions (A/F=20-22). Particularly, for open-valve injection strategy that yielded a stratified mixture, the degree of this correlation lied in the range ≈-0.4 to -0.8, being lower for the locally measured A/F Ratio and higher for the globally evaluated one. Some issues related to the opposite gradients of the calibRation curves deduced for the measurement of the global and local in-cylinder A/F Ratios need to be examined outside the engine using a combustion facility with controlled conditions of pressure, temperature, turbulence intensity, and dilution by combustion residuals. © 2003 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
P G Aleiferis - One of the best experts on this subject based on the ideXlab platform.
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flame chemiluminescence studies of cyclic combustion variations and air to fuel Ratio of the reacting mixture in a lean burn stratified charge spark ignition engine
Combustion and Flame, 2004Co-Authors: P G Aleiferis, Y Hardalupas, A M K P Taylor, Kazuo Ishii, Yasuhiro UrataAbstract:The operating range of lean-burn spark-ignition engines is limited by the level of cyclic variability in the early flame development that typically corresponds to the 0-5% mass fraction burned duRation. An experimental investigation was undertaken to study the levels of flame chemiluminescence in an optical stratified-charge spark-ignition engine, using a Cassegrain optical system with high spatial resolution. Measurements of OH and CH-radical intensities were simultaneously acquired with double flame images per cycle for a range of Air-to-Fuel Ratios (A/F=12-22). These signals of chemiluminescence were used to evaluate the in-cylinder equivalence Ratio of the reacting mixture and to further examine its contribution to the flame growth speed and the cyclic variability in the crank angle by which 5% mass fraction was burned (θXb5%). Specifically, the Ratio of the OH/CH chemiluminescence signals was calibrated in the engine and tested extensively for different injection strategies and spark advances, to measure the "global" and "local" in-cylinder A/F Ratio around the spark plug. The complications encountered towards this goal are discussed in detail. The results showed that the equivalence Ratio exhibited large variations on a cycle-by-cycle basis and consistently produced negative correlation coefficients with θXb5%, especially for lean-set operating conditions (A/F=20-22). Particularly, for open-valve injection strategy that yielded a stratified mixture, the degree of this correlation lied in the range ≈-0.4 to -0.8, being lower for the locally measured A/F Ratio and higher for the globally evaluated one. Some issues related to the opposite gradients of the calibRation curves deduced for the measurement of the global and local in-cylinder A/F Ratios need to be examined outside the engine using a combustion facility with controlled conditions of pressure, temperature, turbulence intensity, and dilution by combustion residuals. © 2003 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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flame chemiluminescence studies of cyclic combustion variations and air to fuel Ratio of the reacting mixture in a lean burn stratified charge spark ignition engine
Combustion and Flame, 2004Co-Authors: P G Aleiferis, Y Hardalupas, Kazuo Ishii, A M K P Taylo, Yasuhiro UrataAbstract:The operating range of lean-burn spark-ignition engines is limited by the level of cyclic variability in the early flame development that typically corresponds to the 0-5% mass fraction burned duRation. An experimental investigation was undertaken to study the levels of flame chemiluminescence in an optical stratified-charge spark-ignition engine, using a Cassegrain optical system with high spatial resolution. Measurements of OH and CH-radical intensities were simultaneously acquired with double flame images per cycle for a range of Air-to-Fuel Ratios (A/F=12-22). These signals of chemiluminescence were used to evaluate the in-cylinder equivalence Ratio of the reacting mixture and to further examine its contribution to the flame growth speed and the cyclic variability in the crank angle by which 5% mass fraction was burned (θXb5%). Specifically, the Ratio of the OH/CH chemiluminescence signals was calibrated in the engine and tested extensively for different injection strategies and spark advances, to measure the "global" and "local" in-cylinder A/F Ratio around the spark plug. The complications encountered towards this goal are discussed in detail. The results showed that the equivalence Ratio exhibited large variations on a cycle-by-cycle basis and consistently produced negative correlation coefficients with θXb5%, especially for lean-set operating conditions (A/F=20-22). Particularly, for open-valve injection strategy that yielded a stratified mixture, the degree of this correlation lied in the range ≈-0.4 to -0.8, being lower for the locally measured A/F Ratio and higher for the globally evaluated one. Some issues related to the opposite gradients of the calibRation curves deduced for the measurement of the global and local in-cylinder A/F Ratios need to be examined outside the engine using a combustion facility with controlled conditions of pressure, temperature, turbulence intensity, and dilution by combustion residuals. © 2003 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
Guoming G. Zhu - One of the best experts on this subject based on the ideXlab platform.
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Transient Air-to-Fuel Ratio Control of an Spark Ignited Engine Using Linear Quadratic Tracking
Journal of Dynamic Systems Measurement and Control, 2013Co-Authors: Pace Stephen D, Guoming G. ZhuAbstract:Modern spark ignited (SI) internal combustion engines maintain their Air-to-Fuel Ratio (AFR) at a desired level to maximize the three-way catalyst conversion efficiency and durability. However, maintaining the engine AFR during its transient opeRation is quite challenging due to rapid changes of driver demand or engine throttle. Conventional transient AFR control is based upon the inverse dynamics of the engine fueling dynamics and the measured mass air flow (MAF) rate to obtain the desired AFR of the gas mixture trapped in the cylinder. This paper develops a linear quadratic (LQ) tracking controller to regulate the transient AFR based upon a control-oriented model of the engine port fuel injection (PFI) wall wetting dynamics and the air intake dynamics from the measured airflow to the manifold pressure. The LQ tracking controller is designed to optimally track the desired AFR by minimizing the error between the trapped in-cylinder air mass and the product of the desired AFR and fuel mass over a given time interval. The performance of the optimal LQ tracking controller was compared with the conventional transient fueling control based on the inverse fueling dynamics through simulations and showed improvement over the baseline conventional inverse fueling dynamics controller. To validate the control strategy on an actual engine, a 0.4 l single cylinder direct-injection (DI) engine was used. The PFI wall wetting dynamics were simulated in the engine controller after the DI injector control signal. Engine load transition tests for the simulated PFI case were conducted on an engine dynamometer, and the results showed improvement over the baseline transient fueling controller based on the inverse fueling dynamics.
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ACC - Air-to-Fuel Ratio regulation during SI to HCCI combustion mode transition using the LQ tracking control
2012 American Control Conference (ACC), 2012Co-Authors: Xiaojian Yang, Guoming G. Zhu, Xuefei ChenAbstract:The combustion mode transition between spark ignition (SI) and homogeneous charge compression ignition (HCCI) combustions of an internal combustion (IC) engine is challenging due to the distinct engine operating parameters over the two combustion modes and the cycle-to-cycle residue gas dynamics during the mode transition. The control problem becomes even more complicated for a multi-cylinder engine without camless valve actuation. This paper studies the combustion mode transition problem of a multi-cylinder IC engine with dual-stage valve lift and electrical variable valve timing (VVT) systems. Hardware-in-the-loop (HIL) simulations were used to develop and validate the proposed control strategies. The HIL simulation results show that smooth combustion mode transition can be realized utilizing the hybrid combustion mode in a few engine cycles and in-cylinder Air-to-Fuel Ratio during the mode transition needs to be regulated to the desired level. This paper presents a model based linear quadratic tracking strategy to track the desired Air-to-Fuel Ratio by controlling the engine throttle. The HIL simulations demonstrated the effectiveness of the developed control strategies. As a result, it is feasible to have a smooth combustion mode transition with dual-stage valve lift and electrical VVT systems.
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ACC - Air-to-Fuel Ratio control with adaptive estimation of biofuel content for diesel engine LNT regeneRation
2012 American Control Conference (ACC), 2012Co-Authors: Xuefei Chen, Yueyun Wang, Ibrahim Haskara, Guoming G. ZhuAbstract:This paper presents a method of controlling the Air-to-Fuel Ratio (AFR) based upon an adaptively estimated biodiesel fuel content for a diesel engine equipped with the lean NOx trap (LNT) aftertreatment system. The fuel content (or percentage of biodiesel fuel) is estimated by an adaptive estimation scheme based upon the exhaust oxygen sensor signal during the normal engine opeRations and during the LNT regeneRation when the AFR is controlled in a closed loop. The engine system was modeled by a third order linear system in this study. A Linear Quadratic optimal tracking controller was used to regulate the engine AFR to the desired level during the LNT regeneRation period. The closed loop system robustness with respect to the air flow measurement error and the fuel content estimation error is also analyzed. Three adaptive control schemes were studied through simulations, and the best performance was obtained for the dual-gain scheme, where the low adaptive estimation gain is used during normal engine opeRations and high gain is used during the LNT regeneRation.
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Optimal LQ Transient Air-to-Fuel Ratio Control of an Internal Combustion Engine
ASME 2011 Dynamic Systems and Control Conference and Bath ASME Symposium on Fluid Power and Motion Control Volume 2, 2011Co-Authors: Pace Stephen D, Guoming G. ZhuAbstract:Most modern spark ignited (SI) internal combustion engines maintain their Air-to-Fuel Ratio (AFR) at a desired level to maximize the three-way catalyst conversion efficiency and to extend its life. However, maintaining the engine AFR during its transient opeRation is quite challenging due to rapid changes of driver demands. Conventional transient AFR control is based upon the inverse dynamics of the engine port-fuel-injection well-wetting dynamics and the measured mass air flow rate. This paper develops a dynamic linear quadratic (LQ) tracking controller to regulate the AFR using a control oriented model of the wall wetting dynamics of a port fuel injector (PFI) and estimated transport delays of the airflow travel and throttle dynamics. The LQ tracking controller is designed to optimally track the measured airflow through the throttle during engine transients over a given time interval. The performance of the optimal LQ tracking controller was compared with the conventional inverse fueling dynamics through simulations and showed improvement over the baseline controller.Copyright © 2011 by ASME
W.c. Maskell - One of the best experts on this subject based on the ideXlab platform.
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Theory and simulation of a miniature zirconia sensor for control of the Air-to-Fuel Ratio in combustion systems
IEEE Sensors Journal, 2001Co-Authors: M. Benammar, W.c. MaskellAbstract:The theory of opeRation on both sides of stoichiometry of a miniature zirconia oxygen pump-gauge incorporating a diffusion hole is discussed. Computer simulation of the sensor output when used for monitoring the Air-to-Fuel Ratio in a combustion system burning pure methane in air is given. It is shown that for a sinusoidal current applied to the pump, the gauge provides an oscillating EMF from which the Air-to-Fuel Ratio may be determined unambiguously without the use of a reference and/or pseudo-reference.
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A novel miniature zirconia gas sensor with pseudo-reference Part III: Simple implementation for the determination of Air-to-Fuel Ratio
Journal of Applied Electrochemistry, 1995Co-Authors: M. Benammar, W.c. MaskellAbstract:A novel mode of opeRation of a double-chamber zirconia oxygen sensor is presented. A pseudo-reference gas was generated in one chamber of the sensor to pin the potentials of the electrodes acting to pump oxygen to or from the other chamber. The circuitry was simple and readily implemented. The sensor was tested in the flue of a gas-burning system and shown to provide an output which enabled the normalized Air-to-Fuel Ratio, λ, to be measured over the range 0.7 < λ < 1.7. The characteristics are discussed from a theoretical standpoint.
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A novel miniature zirconia gas sensor with pseudo-reference: Amperometric opeRation providing unambiguous determination of Air-to-Fuel Ratio
Applied Physics A Solids and Surfaces, 1993Co-Authors: Mohieddine Benammar, W.c. MaskellAbstract:The problem of ambiguity of the output of a single-chamber amperometric zirconia oxygen sensor with the possible confusion of lean and rich opeRation of a combustion system is well known. The solution previously proposed entails the addition of a second chamber containing a piped reference gas such as air. In this paper the novel solution proposed is to generate a pseudo-reference gas, which always contains excess oxygen, in the second chamber so eliminating the need for a piped reference gas. The detailed theory of the device in one particular mode is developed and confirmed by experimental tests in O2-N2 and CO-CO2-N2 mixtures. The device was also operated in the flue of a gas-burning system over a wide range of Air-to-Fuel Ratios from rich to lean. The output changed monotonically over the whole range switching sign as stoichiometry was traversed. An amperometric zirconia gas sensor with such a characteristic has previously only been described for a sensor with supplied reference gas of fixed composition.
Xuefei Chen - One of the best experts on this subject based on the ideXlab platform.
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Optimal Air-to-Fuel Ratio Tracking Control With Adaptive Biofuel Content Estimation for LNT RegeneRation
IEEE Transactions on Control Systems Technology, 2014Co-Authors: Xuefei Chen, Yueyun Wang, Ibrahim HaskaraAbstract:This paper presents an optimal control method of tracking the desired Air-to-Fuel Ratio (AFR) based upon the adaptively estimated biofuel content for internal combustion engines equipped with the lean NOx trap (LNT) aftertreatment system. This biofuel content (or percentage of biofuel) is adaptively estimated based upon the exhaust oxygen AFR sensor signal under both the normal engine opeRations with lean combustion and the LNT regeneRation opeRations with the closed-loop AFR control. The engine system is approximated by a third-order linear system in this paper. A linear quadratic optimal tracking controller is used to track the desired engine AFR during the LNT regeneRation period. The robust stability of the closed-loop tracking control system with the adaptive biofuel content estimation is guaranteed over the entire biofuel range and engine speed between 600 and 5500 rpm by using the robust stability criteria for linear parameter variation systems, where the biofuel gain and engine speed are considered as the variable parameter. Several adaptive control schemes are studied through simulations, and then the selected control strategies are evaluated through dynamometer tests for a lean burn spark ignition engine. The best performance is achieved by the gain-scheduled adaptive scheme.
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ACC - Air-to-Fuel Ratio regulation during SI to HCCI combustion mode transition using the LQ tracking control
2012 American Control Conference (ACC), 2012Co-Authors: Xiaojian Yang, Guoming G. Zhu, Xuefei ChenAbstract:The combustion mode transition between spark ignition (SI) and homogeneous charge compression ignition (HCCI) combustions of an internal combustion (IC) engine is challenging due to the distinct engine operating parameters over the two combustion modes and the cycle-to-cycle residue gas dynamics during the mode transition. The control problem becomes even more complicated for a multi-cylinder engine without camless valve actuation. This paper studies the combustion mode transition problem of a multi-cylinder IC engine with dual-stage valve lift and electrical variable valve timing (VVT) systems. Hardware-in-the-loop (HIL) simulations were used to develop and validate the proposed control strategies. The HIL simulation results show that smooth combustion mode transition can be realized utilizing the hybrid combustion mode in a few engine cycles and in-cylinder Air-to-Fuel Ratio during the mode transition needs to be regulated to the desired level. This paper presents a model based linear quadratic tracking strategy to track the desired Air-to-Fuel Ratio by controlling the engine throttle. The HIL simulations demonstrated the effectiveness of the developed control strategies. As a result, it is feasible to have a smooth combustion mode transition with dual-stage valve lift and electrical VVT systems.
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ACC - Air-to-Fuel Ratio control with adaptive estimation of biofuel content for diesel engine LNT regeneRation
2012 American Control Conference (ACC), 2012Co-Authors: Xuefei Chen, Yueyun Wang, Ibrahim Haskara, Guoming G. ZhuAbstract:This paper presents a method of controlling the Air-to-Fuel Ratio (AFR) based upon an adaptively estimated biodiesel fuel content for a diesel engine equipped with the lean NOx trap (LNT) aftertreatment system. The fuel content (or percentage of biodiesel fuel) is estimated by an adaptive estimation scheme based upon the exhaust oxygen sensor signal during the normal engine opeRations and during the LNT regeneRation when the AFR is controlled in a closed loop. The engine system was modeled by a third order linear system in this study. A Linear Quadratic optimal tracking controller was used to regulate the engine AFR to the desired level during the LNT regeneRation period. The closed loop system robustness with respect to the air flow measurement error and the fuel content estimation error is also analyzed. Three adaptive control schemes were studied through simulations, and the best performance was obtained for the dual-gain scheme, where the low adaptive estimation gain is used during normal engine opeRations and high gain is used during the LNT regeneRation.