Transient Air/Fuel Ratio Controller Identification Using Repetitive Control

2004 ◽  
Vol 126 (4) ◽  
pp. 781-789 ◽  
Author(s):  
Andrew W. Osburn ◽  
Matthew A. Franchek
Keyword(s):  
System Identification ◽  
Experimental Validation ◽  
Engine Speed ◽  
Rapid Determination ◽  
Warm Up ◽  
Identification Process ◽  
Si Engines ◽  
Feedforward Controller ◽  
Fueling Control

Presented in this paper is a feedforward controller identification process for the transient fueling control of spark ignition (SI) engines. The objective of an SI fueling control system is to guarantee a prespecified air–fuel (A/F) ratio, despite changing driver demands commanded through the throttle. The controller identification process is based on standard system identification tools and is comprised of three steps. The first step involves the design and implementation of a repetitive feedback controller. Next, the engine is subjected to a prespecified periodic throttle motion for which the repetitive controller achieves precise A/F control as t→∞. Finally, using the engine speed, the mass air flow, and the fuel pulsewidth information during precise fueling conditions, the feedforward fueling controller is identified using standard parametric system identification tools. This identification process can be performed during engine warm-up, thereby enabling a rapid determination of the fueling requirements as a function of temperature. Experimental validation is provided on a 1999 Ford 4.6L V-8 fuel injected engine with sequential port injection.

Data Driven Feedforward Transient Fueling Controller Identification for Spark Ignition Engines

2005 ◽  
Author(s):  
Matthew A. Franchek ◽  
Jackie Mohrfeld ◽  
Andy Osburn
Keyword(s):  
Steady State ◽  
Nonlinear Behavior ◽  
Spark Ignition ◽  
Spark Ignition Engines ◽  
Transient Phenomena ◽  
Crank Angle ◽  
Si Engines ◽  
Separate System ◽  
Feedforward Controller ◽  
Fueling Control

Presented in this paper is a feedforward fueling controller identification methodology for the transient fueling control of spark ignition (SI) engines. The proposed transient feedforward controller is identified and executed in the crank angle domain, and operates in tandem with a steady state fueling controller. The hypothesis is that the feedforward fueling control of SI engines can be separated into steady state and transient phenomena, and that the majority of the nonlinear behavior associated with engine fueling can be captured with nonlinear steady state compensation. The proposed transient controller identification process is built from standard nonparametric identification techniques using spectral density functions where crank angle serves as the independent variable. Two separate system identification problems are solved to identify the air path dynamics and the fuel path dynamics. The transient feedforward controller is then calculated as the ratio of the air path-over-the fuel path dynamics so that the fuel path dynamics match the air path dynamics. Consequently fueling is coordinated with the fresh air charge during transient conditions. It will be shown that a linear transient feedforward-fueling controller operating in tandem with a nonlinear steady state fueling controller can achieve air-fuel ratio (AFR) regulation comparable to a production controller without the extensive controller calibration process. The engine used in this investigation is a 1999 Ford 4.6L V-8 fuel injected engine.

Weak Beam Imaging and Diffraction Studies of Stacking Faults in Silicon

1976 ◽  
Vol 34 ◽  
pp. 590-591
Author(s):  
T. Y. Tan ◽  
W. K. Tice
Keyword(s):  
Fast Neutron ◽  
Rapid Determination ◽  
Stacking Faults ◽  
Imaging Method ◽  
Large Reduction ◽  
Dislocation Loops ◽  
Fringe Spacing ◽  
Weak Beam ◽  
Kinematical Theory

In studying ion implanted semiconductors and fast neutron irradiated metals, the need for characterizing small dislocation loops having diameters of a few hundred angstrom units usually arises. The weak beam imaging method is a powerful technique for analyzing these loops. Because of the large reduction in stacking fault (SF) fringe spacing at large sg, this method allows for a rapid determination of whether the loop is faulted, and, hence, whether it is a perfect or a Frank partial loop. This method was first used by Bicknell to image small faulted loops in boron implanted silicon. He explained the fringe spacing by kinematical theory, i.e., ≃l/(Sg) in the fault fringe in depth oscillation. The fault image contrast formation mechanism is, however, really more complicated.

Methods for rapid determination of pecan (Carya illinoensis) seed viability

2017 ◽  
Vol 45 (2) ◽  
pp. 455-464
Author(s):  
T.T. Xue ◽  
J. Liu ◽  
Y.B. Shen ◽  
G.Q. Liu
Keyword(s):  
Rapid Determination ◽  
Seed Viability ◽  
Carya Illinoensis
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