The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform
Imad Hassan Makki - One of the best experts on this subject based on the ideXlab platform.
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Linear parameter-varying Lean Burn air-fuel ratio control for a spark ignition Engine
Journal of Dynamic Systems Measurement and Control-transactions of The Asme, 2007Co-Authors: Feng Zhang, Matthew A. Franchek, Karolos M. Grigoriadis, Imad Hassan MakkiAbstract:In 2003, U.S. consumed about 20 million barrels of oil per day. The gasoline for cars and light trucks accounts for 45% of the total oil consumption. Lean Burn technology for gasoline Engines has drawn great attention during the past decade, largely due to its potential for improving fuel economy and reducing CO2 emissions 1. A Lean Burn Engine is designed to operate at high intake manifold pressure with an air-fuel ratio greater than 10 and less than 23. Consequently, combustion efficiency can be improved through reduced pumping losses and enhanced thermodynamic efficiency. Compared to the conventional port fuel injection PFI Engine, the gasoline Lean Burn Engine presents a new set of challenges to the Engine control community. The main challenge for Lean Burn technology is that, under Lean operating conditions, the conventional three-way catalyst TWC system is no longer effective in reducing NOx pollutants. A special TWC with NOx trapping and conversion capabilities, known as Lean NOx trap LNT, has to be used downstream of the conventional TWC to meet the government emission standards. During the Lean operation, NOx in the feed gas is stored in the LNT. When the stored NOx reaches a certain threshold, the trap must be purged by switching to rich operation for a short period of time to regenerate the storage capacity and recover the efficiency. The NOx released from the LNT during the purge period is converted into non-polluting nitrogen by the rich air-fuel mixture 2‐5. Properly managing the storage and purge cycles is critical for achieving the fuel economy and NOx emission control targets of the Lean Burn gasoline Engine. The desired tailpipe air-fuel ratio profile reference air-fuel ratio is defined by the LNT purge control 6,7, with the objectives of optimizing fuel economy while satisfying emission constraints. Therefore, it is necessary to design a controller to regulate the tailpipe air-fuel ratio to follow the air-fuel reference for both the NOx storage phase Lean operation and the purge phase rich operation in order to accomplish the LNT purge control. In this paper, we concentrate on the air-fuel ratio control for the storage phase, that is, the design of the “outer-feedback loop” air-fuel ratio controller is considered. A linear universal exhaust gas oxygen UEGO sensor is used downstream of the LNT to measure the tailpipe air-fuel ratio. The air-fuel ratio controller to be designed is used to generate the commanded air-fuel ratio for the fuel injection system. During the storage phase when the Engine is operating under Lean conditions, the air-fuel ratio is selected to i meet the driver’s demand, ii maximize fuel economy, and iii satisfy other constraints, such as Lean Burn limit 7. These requirements dictate the set-point selection, and the optimal choice for the air-fuel ratio in the storage phase is usually a constant set-point for steady state operation.
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Linear Parameter-Varying Lean Burn Air-Fuel Ratio Control
Proceedings of the 44th IEEE Conference on Decision and Control, 2005Co-Authors: Feng Zhang, K.m. Grigoriadist, Matthew A. Franchek, Imad Hassan MakkiAbstract:Maximization of the fuel economy of the Lean Burn SI Engine strongly depends on precise air-fuel ratio control. A great challenge associated with the air-fuel ratio feedback control is the large variable time delay in the exhaust system. In this paper, a systematic development of an air-fuel ratio controller based on post-LNT UEGO sensor feedback using linear parameter-varying (LPV) control is presented. Satisfactory stability and disturbance rejection performance is obtained in the face of the variable time delay. The LPV controller is simplified to an explicit parameterized gain scheduled 1st order controller form for the ease of implementation. A Ford F-150 truck with a V8 4.6 Liter Lean Burn Engine was used to demonstrate the LPV air-fuel ratio control design. Both simulation and experimental results demonstrate that the designed controller regulates the tailpipe air-fuel ratio to the preset reference for the full Engine operating range.
J. T. Kubesh - One of the best experts on this subject based on the ideXlab platform.
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The hybrid rich-Burn/Lean-Burn Engine
Journal of Engineering for Gas Turbines and Power, 1997Co-Authors: D.p. Meyers, J. T. KubeshAbstract:This paper describes a new low-emissions Engine concept called the hybrid rich-Burn/Lean-Burn (HRBLB) Engine. In this concept a portion of the cylinders of a multicylinder Engine are fueled with a very rich natural gas--air mixture. The remaining cylinders are operated with a Lean mixture of natural gas and air and supplemented with the rich combustion exhaust. The goal of this unique concept is the production of extremely low NO{sub x} (e.g., 5 ppm when corrected to 15% exhaust oxygen content). This is a accomplished by operating outside the combustion limits where NO{sub x} is produced. In rich combustion an abundance of hydrogen and carbon monoxide is produced. Catalyst treatment of the rich exhaust can be employed to increase the hydrogen concentration and decrease the carbon monoxide concentration simultaneously. The hydrogen-enriched exhaust is used to supplement the Lean mixture cylinders to extend the Lean limit of combustion, and thus produces ultralow levels of NO{sub x}. Results to date have shown NO{sub x} levels as low as 8 ppm at 15% oxygen can be achieved with good combustion stability and thermal efficiency.
Shinichi Matsumoto - One of the best experts on this subject based on the ideXlab platform.
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denox catalyst for automotive Lean Burn Engine
Catalysis Today, 1996Co-Authors: Shinichi MatsumotoAbstract:Abstract The performance and durability of Cu-ZSM-5 were studied. Cu-ZSM-5 has fairly high NOx reduction activity but its durability is insufficient for practical use. We developed a new deNOx catalyst. In this catalyst, we call NOx storage reduction catalyst (NSR-catalyst), NOx emitted from an Engine at Lean A F operation is stored and this stored NOx is reduced at stoichiometric or rich operation. This catalyst has been used on the Toyota CARINA with a Lean-Burn Engine in Japan since 1994. This report outlines the results of our study on Cu-ZSM-5 and NSR-catalyst.
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The new concept 3-way catalyst for automotive Lean-Burn Engine: NOx storage and reduction catalyst
Catalysis Today, 1996Co-Authors: Naoki Takahashi, Shinichi Matsumoto, Hirofumi Shinjoh, Tomoko Iijima, Tadashi Suzuki, Kiyoshi Yamazaki, Koji Yokota, Hiromasa Suzuki, Naoto Miyoshi, Tsuneyuki TanizawaAbstract:The new concept 3-way catalysts for a Lean-Burn Engine have been developed, and their NOx purification mechanisms have been studied. The catalysts consist of precious metals, aluminum oxide and some other metal compounds such as NOx, storage compounds. NOx is oxidized over the precious metals and stored as nitrate ion combined with NOx storage compounds under oxidizing conditions. The stored NOx, is reduced to N2 under stoichiometric and reducing conditions. The NOx, storage capacity is deteriorated by sulfur. The improved catalysts showed sufficient NOx, conversion durability in the Japanese 10–15 mode test.
D.p. Meyers - One of the best experts on this subject based on the ideXlab platform.
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The hybrid rich-Burn/Lean-Burn Engine
Journal of Engineering for Gas Turbines and Power, 1997Co-Authors: D.p. Meyers, J. T. KubeshAbstract:This paper describes a new low-emissions Engine concept called the hybrid rich-Burn/Lean-Burn (HRBLB) Engine. In this concept a portion of the cylinders of a multicylinder Engine are fueled with a very rich natural gas--air mixture. The remaining cylinders are operated with a Lean mixture of natural gas and air and supplemented with the rich combustion exhaust. The goal of this unique concept is the production of extremely low NO{sub x} (e.g., 5 ppm when corrected to 15% exhaust oxygen content). This is a accomplished by operating outside the combustion limits where NO{sub x} is produced. In rich combustion an abundance of hydrogen and carbon monoxide is produced. Catalyst treatment of the rich exhaust can be employed to increase the hydrogen concentration and decrease the carbon monoxide concentration simultaneously. The hydrogen-enriched exhaust is used to supplement the Lean mixture cylinders to extend the Lean limit of combustion, and thus produces ultralow levels of NO{sub x}. Results to date have shown NO{sub x} levels as low as 8 ppm at 15% oxygen can be achieved with good combustion stability and thermal efficiency.
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The hybrid rich-Burn/Lean Burn Engine. Part 2
1996Co-Authors: J.a. Smith, D. Podnar, D.p. MeyersAbstract:Southwest Research Institute (SwRI) has developed a unique Engine technology called Hybrid Rich-Burn/Lean-Burn (HRBLB) that capitalizes on the low production of oxides of nitrogen (NO{sub x}) during extremely rich and Lean combustion. The HRBLB concept is predicated on simultaneous combustion of extremely rich and Lean natural gas-air mixtures in separate cylinders. Rich exhaust products undergo a catalytic water-gas shift reaction to form an intermediate combustible fuel composed of carbon monoxide, water vapor, hydrogen, and carbon dioxide. All of the intermediate fuel is added to Lean natural gas-air mixtures in other cylinders to enhance ignitability that would otherwise result in misfire. This paper presents results obtained during the development of a stationary, turbocharged, and intercooled, 18-liter HRBLB Engine. Results show that NO{sub x} can be reduced by a factor of 2.5 to 3.5 relative to stock Engine emissions at equivalent efficiency. The HRBLB Engine has demonstrated corrected NO{sub x} (15% O{sub 2}) levels of 23 ppm at rated load with thermal efficiencies of 35%.
Matthew A. Franchek - One of the best experts on this subject based on the ideXlab platform.
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A Predictive Strategy to Control Time-Varying Delay Systems: Lean-Burn Engines
Volume 3: Multiagent Network Systems; Natural Gas and Heat Exchangers; Path Planning and Motion Control; Powertrain Systems; Rehab Robotics; Robot Man, 2015Co-Authors: Morteza Mohammadzaheri, Karolos M. Grigoriadis, Reza Tafreshi, Behrouz Ebrahimi, Matthew A. FranchekAbstract:In this paper, a control design synthesis is presented for processes modeled by a first-order time-varying lag with a time-varying delay. The basis of the proposed control method is a feedforward-feedback control system in which its stability, both in continuous and discrete time domains, is first proved in the absence of the time delay. A predictive model with an adaptive horizon is then introduced to address the effect of the time-varying delay. The system’s closed-loop response is demonstrated for fueling control in Lean-Burn gasoline spark ignition Engines with varying transport and combustion delays. The developed methodology is validated on a Ford F-150 SI Lean-Burn Engine model with large time-varying delay in the control loop.Copyright © 2015 by ASME
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Linear parameter-varying Lean Burn air-fuel ratio control for a spark ignition Engine
Journal of Dynamic Systems Measurement and Control-transactions of The Asme, 2007Co-Authors: Feng Zhang, Matthew A. Franchek, Karolos M. Grigoriadis, Imad Hassan MakkiAbstract:In 2003, U.S. consumed about 20 million barrels of oil per day. The gasoline for cars and light trucks accounts for 45% of the total oil consumption. Lean Burn technology for gasoline Engines has drawn great attention during the past decade, largely due to its potential for improving fuel economy and reducing CO2 emissions 1. A Lean Burn Engine is designed to operate at high intake manifold pressure with an air-fuel ratio greater than 10 and less than 23. Consequently, combustion efficiency can be improved through reduced pumping losses and enhanced thermodynamic efficiency. Compared to the conventional port fuel injection PFI Engine, the gasoline Lean Burn Engine presents a new set of challenges to the Engine control community. The main challenge for Lean Burn technology is that, under Lean operating conditions, the conventional three-way catalyst TWC system is no longer effective in reducing NOx pollutants. A special TWC with NOx trapping and conversion capabilities, known as Lean NOx trap LNT, has to be used downstream of the conventional TWC to meet the government emission standards. During the Lean operation, NOx in the feed gas is stored in the LNT. When the stored NOx reaches a certain threshold, the trap must be purged by switching to rich operation for a short period of time to regenerate the storage capacity and recover the efficiency. The NOx released from the LNT during the purge period is converted into non-polluting nitrogen by the rich air-fuel mixture 2‐5. Properly managing the storage and purge cycles is critical for achieving the fuel economy and NOx emission control targets of the Lean Burn gasoline Engine. The desired tailpipe air-fuel ratio profile reference air-fuel ratio is defined by the LNT purge control 6,7, with the objectives of optimizing fuel economy while satisfying emission constraints. Therefore, it is necessary to design a controller to regulate the tailpipe air-fuel ratio to follow the air-fuel reference for both the NOx storage phase Lean operation and the purge phase rich operation in order to accomplish the LNT purge control. In this paper, we concentrate on the air-fuel ratio control for the storage phase, that is, the design of the “outer-feedback loop” air-fuel ratio controller is considered. A linear universal exhaust gas oxygen UEGO sensor is used downstream of the LNT to measure the tailpipe air-fuel ratio. The air-fuel ratio controller to be designed is used to generate the commanded air-fuel ratio for the fuel injection system. During the storage phase when the Engine is operating under Lean conditions, the air-fuel ratio is selected to i meet the driver’s demand, ii maximize fuel economy, and iii satisfy other constraints, such as Lean Burn limit 7. These requirements dictate the set-point selection, and the optimal choice for the air-fuel ratio in the storage phase is usually a constant set-point for steady state operation.
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Linear Parameter-Varying Lean Burn Air-Fuel Ratio Control
Proceedings of the 44th IEEE Conference on Decision and Control, 2005Co-Authors: Feng Zhang, K.m. Grigoriadist, Matthew A. Franchek, Imad Hassan MakkiAbstract:Maximization of the fuel economy of the Lean Burn SI Engine strongly depends on precise air-fuel ratio control. A great challenge associated with the air-fuel ratio feedback control is the large variable time delay in the exhaust system. In this paper, a systematic development of an air-fuel ratio controller based on post-LNT UEGO sensor feedback using linear parameter-varying (LPV) control is presented. Satisfactory stability and disturbance rejection performance is obtained in the face of the variable time delay. The LPV controller is simplified to an explicit parameterized gain scheduled 1st order controller form for the ease of implementation. A Ford F-150 truck with a V8 4.6 Liter Lean Burn Engine was used to demonstrate the LPV air-fuel ratio control design. Both simulation and experimental results demonstrate that the designed controller regulates the tailpipe air-fuel ratio to the preset reference for the full Engine operating range.