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Air-Fuel Ratio

The Experts below are selected from a list of 9294 Experts worldwide ranked by ideXlab platform

Yihu Wu – 1st expert on this subject based on the ideXlab platform

  • A Compensate Method for Air Fuel Ratio in Gasoline Engine Start Process Based on Dynamic Fuel Film Model
    2010 International Conference on Measuring Technology and Mechatronics Automation, 2010
    Co-Authors: Yihu Wu, Biao Kuang, Huan-chun Gong

    Abstract:

    During the gasoline engine start process, air fuel Ratio of gasoline engine always greatly departs the theoretical air fuel Ratio by the affection of intake pipe fuel film. To decrease exhaust emission in engine start process, the dynamic characteristic of intake pipe fuel film is analyzed; a new dynamic fuel film model of intake pipe based on Aquino model is presented, and a fuel compensation method based on theory of adverse is presented. Two conditions of a gasoline engine start process are simulated with SIMULINK based on presented model and the compensation method; the simulated results of air fuel Ratio by present fuel film model and by Aquino model are given out. The result shows that, the presented intake pipe fuel film model and the fuel compensation method can compensate air fuel Ratio near to the theoretical air fuel Ratio in the gasoline engine start process.

  • Predictive control for air fuel Ratio based on adaptive expand particle swarm optimization
    2008 7th World Congress on Intelligent Control and Automation, 2008
    Co-Authors: Yihu Wu

    Abstract:

    Because the oxygen sensor is installed into the vent-pipe of gasoline engine, the air fuel Ratio signal of gasoline engine exists transmission delay, which affects the control accuracy of air fuel Ratio if using directive air fuel Ratio sensor signal. To overcome air fuel Ratio transmission delay affection, a new air fuel Ratio predictive control method was provided using adaptive expanded particle optimization in this paper. Particle is refreshed using individual and local extremum in the basic PSO algorithm. To improve the global convergence, particle is refreshed by multi-particle strategy; at the same time, parameter c0 is adaptive adjusted for fast the convergence of PSO algorithm. Applying adaptive expand PSO algorithm optimize the control serial of air fuel Ratio in the finite time field, and control system stability proof is presented. The simulation was accomplished using experiment data of HQ495 gasoline engine, and the results show that the predictive control method has better performance and the air fuel Ratio error is below 1% if slower throttle change, and the air fuel Ratio error is below 2% if faster throttle change during transient condition, which will help to improve the emission of gasoline engine.

  • The Research on Air Fuel Ratio Predictive Model of Gasoline Engine during Transient Condition
    2007 International Conference on Mechatronics and Automation, 2007
    Co-Authors: Yihu Wu

    Abstract:

    In order to overcome air fuel Ratio transmission delay influence on air fuel Ratio control accuracy of gasoline engine during transient conditions, a new multi-step predictive model of air fuel Ratio based on BP neural network was provided in this paper. Input vectors of neural network multi-step predictive model were determined by the mathematic model of air fuel Ratio, and the derivation of air fuel Ratio reflecting the air fuel Ratio tendency was included within input vectors of neural network to improve the prediction accuracy of air fuel Ratio model. The simulation was accomplished using the experiment data of HL495 gasoline engine during transient conditions, and weight values of back propagation neural network were adjusted by gradient algorithm and adaptive method, and the results show the maximal error of air fuel Ratio predictive model is less than 3% and the average error of that model is less than 2%, and the air fuel Ratio predictive model can accurately approximate air fuel Ratio process of gasoline engine during transient condition.

Imad Hassan Makki – 2nd expert on this subject based on the ideXlab platform

  • Transient lean burn Air-Fuel Ratio linear parameter-varying control using input shaping
    International Journal of Modelling Identification and Control, 2008
    Co-Authors: Feng Zhang, Matthew A. Franchek, Karolos M. Grigoriadis, Imad Hassan Makki

    Abstract:

    Transient Air-Fuel Ratio control for lean burn engines is essential to achieve improved fuel economy and strict federal emission regulations. Unlike conventional Spark Ignition (SI) engines, lean burn engines are no longer operating in a narrow band around stoichiometric resulting in a very challenging Air-Fuel Ratio tracking problem. An approach to combine an input shaping method together with Linear Parameter Varying (LPV) feedback control is proposed in this paper to solve the transient Air-Fuel Ratio tracking problem. LPV Air-Fuel Ratio control has been shown to regulate the Air-Fuel Ratio at steady state engine operating conditions, reduce the variability of the closed-loop system, reject disturbance and guarantee robustness and stability in the presence of variable time delays. In this paper, an input shaping method is used to reduce the cost of feedback, and thereby enhance the Air-Fuel Ratio tracking performance during engine transient opeRations. The prefilter is designed based on the closed-loop dynamics resulting from the LPV design. A systematic input shaping prefilter design process is developed. The designed prefilter successfully extends the closed-loop Air-Fuel Ratio tracking bandwidth. Simulation results using Federal Test Procedure (FTP) drive cycle data are used to demonstrate the effectiveness of the input shaping prefilter. Moreover, the designed prefilter is structurally simple and computationally efficient.

  • 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, 2007
    Co-Authors: Feng Zhang, Matthew A. Franchek, Karolos M. Grigoriadis, Imad Hassan Makki

    Abstract:

    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.

  • Transient lean burn Air-Fuel Ratio control using input shaping method combined with linear parameter-varying control
    2006 American Control Conference, 2006
    Co-Authors: Feng Zhang, Matthew A. Franchek, Karolos M. Grigoriadis, Imad Hassan Makki

    Abstract:

    Transient Air-Fuel Ratio control for lean burn engines is critical to achieve desired fuel economy and meet federal emission regulations. Unlike conventional SI engines, lean burn engines are no longer operating in a narrow band around stoichiometry resulting in a very challenging Air-Fuel Ratio tracking problem. An approach to combine an input shaping method together with a linear parameter varying (LPV) feedback controller is proposed to solve the transient Air-Fuel Ratio tracking problem. In the work of Zhang et al. (2005), a feedback LPV Air-Fuel Ratio controller has been designed to regulate the Air-Fuel Ratio at steady state engine operating conditions, reduce the variability of the closed-loop system, reject disturbances and guarantee robustness and stability. In this paper, an input shaping method is proposed to reduce the cost of feedback, and thereby enhance the Air-Fuel Ratio tracking performance during engine transient opeRations. The prefilter is designed based on the closed-loop dynamics resulting from the LPV design. A systematic input shaping prefilter design process is developed. The designed prefilter successfully extends the closed-loop Air-Fuel Ratio tracking bandwidth. Simulation results are used to demonstrate the effectiveness of the input shaping prefilter. Moreover, the designed prefilter is structurally simple and computationally efficient

R. Mehrotra – 3rd expert on this subject based on the ideXlab platform

  • Air/fuel Ratio control using sliding mode methods
    Proceedings of the 1999 American Control Conference (Cat. No. 99CH36251), 1999
    Co-Authors: J.k. Pieper, R. Mehrotra

    Abstract:

    To meet demands for high performance and low fuel consumption and emissions, control of air/fuel Ratio in spark ignition (SI) engines has received significant attention. Here, a nonlinear, fuel injected SI engine model is developed which includes intake manifold, fuel wall-wetting and crankshaft dynamics as well as load effects and process delays inherent in four-stroke engines. A sliding mode controller is designed and implemented for a linearized model using state estimates.