Adaptive air–fuel ratio control scheme and its experimental validations for port‐injected spark ignition engines

To maintain the stoichiometric air–fuel ratio (AFR), this paper presents a model‐based adaptive AFR control scheme for port‐injected spark ignition engines. The utilized mean‐value model in control design accounts for the impingement and the evaporation process of the injected fuel on the walls and calculates on the uncertainties in the dynamics of the intake manifold and crankshaft rotation. A fueling controller with adaptive update laws is derived for estimating the uncertain parameters related to inaccuracies in air flow and fuel delivery into the cylinders and engine torque production, which is implemented by utilizing engine speed, manifold pressure and temperature, air mass flow rate at the throttle, and the universal exhaust gas oxygen (UEGO) sensor information, without knowledge of the fuel flow mass. Theoretical analysis shows that the proposed strategy is able to regulate the AFR against the parameter uncertainties. Moreover, both simulation and experiment on an engine test bench demonstrate the capability of the adaptive controller to recover the performance and robustness properties of the control system in the presence of various operating conditions and uncertainties including air path and fuel path perturbations and load torque disturbance as well. Copyright © 2013 John Wiley & Sons, Ltd.     

Gasoline engine air filter health monitoring by second‐order sliding modes

This paper presents a novel and cheap methodology to classify healthy and clogged air filter. Air filter is an integral part of air intake system of spark ignition engine and is responsible to deliver clean air for combustion process. A clogged air filter may hamper engine power and its drivability performance. As a consequence, its health monitoring becomes mandatory. This task is accomplished by modeling the air filter effects on air flow through inlet manifold pressure by incorporating a newly introduced air filter discharge coefficient (C_af) in its dynamics. The estimation of C_af gives an idea about the health of air filter, as no sensor can be installed to measure it. A second‐order sliding mode observer is employed to estimate immeasurable C_af. Super twisting‐based sliding mode observer requires manifold pressure, engine angular speed, and load torque as input. A successful implementation has been carried out to diagnose clogged and healthy air filter of commercial vehicle engine compliant to on‐board diagnostics version‐II. This characterizes ‘ C_af’ as a clean indicator of air filter health classification. Copyright © 2012 John Wiley & Sons, Ltd.     

Cylinder pressure sensor‐based real‐time combustion phase control approach for SI engines

As one of most effective factors affecting the economy and emissions of internal combustion engines, the combustion phase can maximize performance by tracking its optimum reference. In this study, the combustion phase indicator CA50 is employed for the combustion control of spark‐ignited (SI) engines with the application of a cylinder pressure sensor. In order to suppress the influence of cylinder pressure variation on CA50 measurement, a moving average method is used to stabilize CA50 calculation, and based on measured CA50, a linear autoregressive model is obtained by identification, which depicts the relationship between spark advance and combustion phase. Then, a closed‐loop controller is synthesized for CA50 regulation, including both feedforward and feedback channels. Finally, the proposed strategy is validated by experiments on an SI engine. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Adaptive internal model control: the discrete‐time case

This paper considers the design and analysis of a discrete‐time H₂ optimal robust adaptive controller based on the internal model control structure. The certainty equivalence principle of adaptive control is used to combine a discrete‐time robust adaptive law with a discrete‐time H₂ internal model controller to obtain a discrete‐time adaptive H₂ internal model control scheme with provable guarantees of stability and robustness. The approach used parallels the earlier results obtained for the continuous‐time case. Nevertheless, there are some differences which, together with the widespread use of digital computers for controls applications, justifies a separate exposition. Copyright © 2001 John Wiley & Sons, Ltd.     

Adaptive robust H∞ state feedback control for linear uncertain systems with time‐varying delay

This paper considers the problem of adaptive robust H_∞ state feedback control for linear uncertain systems with time‐varying delay. The uncertainties are assumed to be time varying, unknown, but bounded. A new adaptive robust H_∞ controller is presented, whose gains are updating automatically according to the online estimates of uncertain parameters. By combining an indirect adaptive control method and a linear matrix inequality method, sufficient conditions with less conservativeness than those of the corresponding controller with fixed gains are given to guarantee robust asymptotic stability and H_∞ performance of the closed‐loop systems. A numerical example and its simulation results are given to demonstrate the effectiveness and the benefits of the proposed method. Copyright © 2008 John Wiley & Sons, Ltd.     

Treatment of exhaust gas from vehicles by discharge plasma reactors

The exhaust gas from diesel engines is one of the major causes of air pollution. As one method for pollution control, the authors have been developing plasma reactors. The authors' reactor is a concentric cylinder type which has a glass tube barrier between electrodes. Connecting two of these reactors in series, the NO_x (NO + NO₂) component from diesel engine exhaust gas is decomposed up to 93%. This reactor was mounted on a 3-liter diesel engine and received six-mode load testing at an authorized public facility (JARI, Tsukuba City) and cleared the legal critical value of 350 ppm of NO_x. By this success, the effectiveness of discharge plasma treatment of diesel exhaust gas and its practical evaluation have been confirmed. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 120(2): 1–7, 1997     

Passivity‐based parameterized adaptive disturbance attenuation controller design for switched polynomial nonlinear systems

This paper is concerned with the adaptive disturbance attenuation control problem for a class of switched polynomial nonlinear systems. At first, a parameterized controller is designed to transform the switched polynomial nonlinear systems into switched Hamiltonian systems with polynomial structure. Then, combining with the solve‐parameter algorithm described in this paper, a mixed adaptive passivity and H₂/H_∞ control method is devoted. Comparing with the existing results, the obtained adaptive disturbance attenuation controller has better performance. Finally, a numerical example is given to illustrate the effectiveness of the proposed methods.     

An approach to digital implementation of continuous backstepping adaptive control for linear systems

This paper presents a solution to the problem of digitally implementing backstepping adaptive control for linear systems. The continuous‐time system to be controlled is given a discrete‐time representation in the δ‐operator. A discrete adaptive backstepping controller is then designed for such a discrete‐time model. The effect of the modelling error, generated by the sampling process, is accounted for in the parameter update law by a σ‐modification. It is shown that all the signals (discrete and continuous) of the closed loop are uniformly bounded, with a region of attraction which is a K_∞ function of the sampling rate. An upper bound on the asymptotic tracking error is then given, and shown to be proportional to the sampling period. Copyright © 1999 John Wiley & Sons, Ltd.     

Direct adaptive control for non‐linear uncertain systems with exogenous disturbances

A direct adaptive non‐linear control framework for multivariable non‐linear uncertain systems with exogenous bounded disturbances is developed. The adaptive non‐linear controller addresses adaptive stabilization, disturbance rejection and adaptive tracking. The proposed framework is Lyapunov‐based and guarantees partial asymptotic stability of the closed‐loop system; that is, asymptotic stability with respect to part of the closed‐loop system states associated with the plant. In the case of bounded energy L₂ disturbances the proposed approach guarantees a non‐expansivity constraint on the closed‐loop input–output map. Finally, several illustrative numerical examples are provided to demonstrate the efficacy of the proposed approach. Copyright © 2002 John Wiley & Sons, Ltd.     

Adaptive sliding mode control for fuzzy singular systems with time delay and input nonlinearity

This paper addresses the sliding mode control problem for a class of uncertain Takagi‐Sugeno fuzzy singular systems with state delay and subject to input nonlinearity. Our purpose is focused on designing an adaptive sliding mode controller for such a complex system. First, a new fuzzy integral‐type sliding function is designed. Then, an adaptive sliding mode control scheme is established such that the resulting closed‐loop system is insensitive to all admissible uncertainties and satisfies the reaching condition. Moreover, delay‐dependent sufficient conditions are derived such that the admissibility and the L₂‐L_∞ performance requirement of the sliding mode dynamics can be guaranteed in the presence of time delays, external disturbances, and sector nonlinearity input. Finally, the validity and applicability of the proposed theory are illustrated by a numerical example.     

Proposal and evaluation of a gas engine and gas turbine hybrid cogeneration system in which cascaded heat is highly utilized

A high‐efficiency cogeneration system (CGS) is proposed for utilizing high‐temperature exhaust gas (HTEG) from a gas engine (GE). In the proposed system, for making use of heat energy of HTEG, H₂O turbine (HTb) is incorporated and steam produced by utilizing HTEG is used as working fluid of HTb. HTb exhaust gas is also utilized for increasing power output and for satisfying heat demand in the proposed system. Both of the thermodynamic characteristics of the proposed system and a gas engine CGS (GE‐CGS) constructed by using the original GE are estimated. Energy saving characteristics and CO₂ reduction effects of the proposed CGS and the GE‐CGS are also investigated. It was estimated that the net generated power of the proposed CGS has been increased 25.5% and net power generation efficiency 6.7%, compared with the original GE‐CGS. It was also shown that the proposed CGS could save 27.0% of energy consumption and reduce 1137 t‐CO₂/y, 1.41 times larger than those of GE‐CGS, when a case study was set and investigated. Improvements of performance by increasing turbine inlet temperature were also investigated. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(3): 37– 45, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20708     

Robust adaptive tracking control of uncertain discrete time systems

In this paper, the problem of robust adaptive tracking for uncertain discrete‐time systems is considered from the slowly varying systems point of view. The class of uncertain discrete‐time systems considered is subjected to both 𝓁_∞ to 𝓁_∞ bounded unstructured uncertainty and external additive bounded disturbances. A priori knowledge of the dynamic model of the reference signal to be tracked is not completely known. For such problem, an indirect adaptive tracking controller is obtained by frozen‐time controllers that at each time optimally robustly stabilize the estimated models of the plant and minimize the worst‐case steady‐state absolute value of the tracking error of the estimated model over the model uncertainty. Based on 𝓁_∞ to 𝓁_∞ stability and performance of slowly varying system found in the literature, the proposed adaptive tracking scheme is shown to have good robust stability. Moreover, a computable upper bound on the size of the unstructured uncertainty permitted by the adaptive system and a computable tight upper bound on asymptotic robust steady‐state tracking performance are provided. Copyright © 2005 John Wiley & Sons, Ltd.     

Multiple characteristic model‐based golden‐section adaptive control: Stability and optimization

The characteristic model‐based golden‐section adaptive control (CM‐GSAC) law has been developed for over 20 years in China with a broad range of applications in various fields. However, quite a few theoretical problems remain open despite its satisfying performance in practice. This paper revisits the stability of the CM‐GSAC from its very beginning and explores the underlying implications of the so‐called golden‐section parameter l₂≈0.618. The closed‐loop system, which consists of the CM and the GSAC, is a discrete time‐varying system, and its stability is discussed from three perspectives. First, attentions have been paid to select the optimal controller coefficients such that the closed‐loop system exhibits the best transient performance in the worst case. Second, efforts are made to improve the robustness in the presence of parameter estimation errors, which provide another choice when designing the adaptive controller. Finally, by measuring the slowly time‐varying nature in an explicit inequality form, a bridge is built between the instantaneous stability and the time‐varying stability. In order to relax the constraints on the parameter bounds of the CM, the GSAC is further extended to multiple CMs, which shows more satisfying tracking performance than that of the traditional multiple model adaptive control method. Copyright © 2014 John Wiley & Sons, Ltd.     

Trapped mass estimation in automotive diesel engines based on in-cylinder pressure signal projection

Cylinder pressure signal provides key feedback information that allows for several engine monitoring and control capabilities. During the last few years, the use of cylinder pressure traces for advanced combustion strategies has become the focus of several research works. This is primarily due to the availability of reliable and inexpensive cylinder pressure sensors with expected durability that meets the vehicle lifetime. In this context, several approaches have been proposed to determine the engine trapped mass from the cylinder pressure measurements. A recent innovative approach for trapped charge determination based on a two-dimensional graphical signature is proposed in a previous work. The resulting estimator uses cylinder pressure signal as a unique input and allows to deduce the trapped mass on a cycle by cycle basis in steady and transient operating conditions. It has been validated in a wide range of engine operating conditions using instrumentation and industrial cylinder pressure sensors. This paper provides a theoretical framework and in-depth analysis for the signature based trapped mass estimator. A state-space model for in-cylinder conditions during the compression phase that complies with the signature modeling structure is developed. Extensive numerical investigations using an experimentally validated simulation platform are then performed. The objective is to select the optimal signature generation interval that reduces the impact of cycle to cycle fluctuations in terms of intake valve closing temperature and polytropic index. The obtained results are promising and clearly show the performance and robustness of the signature based trapped mass estimator that can provide relevant feedback information for adaptive engine control systems. It can be easily implemented for real-time monitoring and control in industrial automotive applications.     

Inverse optimal adaptive control for non‐linear uncertain systems with exogenous disturbances

A Lyapunov‐based inverse optimal adaptive control‐system design problem for non‐linear uncertain systems with exogenous ℒ︁₂ disturbances is considered. Specifically, an inverse optimal adaptive non‐linear control framework is developed to explicitly characterize globally stabilizing disturbance rejection adaptive controllers that minimize a nonlinear‐nonquadratic performance functional for non‐linear cascade and block cascade systems with parametric uncertainty. It is shown that the adaptive Lyapunov function guaranteeing closed‐loop stability is a solution to the Hamilton–Jacobi–Isaacs equation for the controlled system and thus guarantees both optimality and robust stability. Additionally, the adaptive Lyapunov function is dissipative with respect to a weighted input–output energy supply rate guaranteeing closed‐loop disturbance rejection. For special integrand structures of the performance functionals considered, the proposed adaptive controllers additionally guarantee robustness to multiplicative input uncertainty. In the case of linear‐quadratic control it is shown that the operations of parameter estimation and controller design are coupled illustrating the breakdown of the certainty equivalence principle for the optimal adaptive control problem. Finally, the proposed framework is used to design adaptive controllers for jet engine compression systems with uncertain system dynamics. Copyright © 2000 John Wiley & Sons, Ltd.     

An adaptive controller–observer scheme for temperature control of non‐chain reactions in batch reactors

In this paper an adaptive controller–observer temperature control scheme is developed for a class of irreversible non‐chain reactions taking place in batch reactors. The scheme is based on a nonlinear observer for the estimation of the heat released by the reaction, where the heat transfer coefficient is adaptively estimated. Tracking of the desired reactor temperature is achieved via a two‐loop control scheme, where an independent adaptive estimate of the heat transfer coefficient is used as well. Remarkably, the observer and the controller can be designed and tuned separately. The convergence of both the nonlinear observer and of the overall controller–observer scheme is analyzed by resorting to a Lyapunov‐like argument. A comparative simulation case study is developed to test the performance of the proposed scheme and compare it with other approaches already known in the literature. Copyright © 2007 John Wiley & Sons, Ltd.     

一种新型车用CNG发动机电控系统的设计

为了实现CNG发动机稀薄燃烧，进一步降低其有害排放，本文设计了车用增压CNG发动机电控系统。该系统电控喷射单元采用空燃比闭环控制和顺序多点喷射技术，利用模糊控制算法实现了对发动机各缸燃气喷射量和喷射时刻的精确控制；针对增压CNG发动机所需点火能量比较高的要求，该系统采用无分电器的高能顺序直接点火控制系统，通过控制各缸点火时刻和点火线圈导通时刻的方法，有效的防止了脉冲的丢失，满足了天然气稀燃所需的点火能量。CNG发动机台架试验结果表明了该系统的有效性。     

Input constrained adaptive tracking for a nonlinear distributed parameter tubular reactor

In this paper we address the problem of local λ tracking of a pre‐specified profile temperature for exothermic chemical reaction in a tubular reactor. In contrast to the various models in the literature, which are usually ordinary differential equations in finite‐dimensional spaces, we use a nonlinear distributed parameter model for both the evolution of the temperature and the reactant concentration. We show under nonrestrictive conditions that an adaptive output feedback controller achieves approximate asymptotic tracking where the pre‐specified asymptotic tracking accuracy, quantified by the design parameter λ>0, is guaranteed. Only a feasibility assumption in terms of the reference temperature and the input constraints is considered. Numerical simulations have been performed to illustrate the performance of the proposed approach. Copyright © 2009 John Wiley & Sons, Ltd.     

Adaptive motion/force tracking control of holonomic constrained mechanical systems: a unified viewpoint

This paper proposes a robust adaptive motion/force tracking controller for holonomic constrained mechanical systems with parametric uncertainties and disturbances. First, two types of well‐known holonomic systems are reformulated as a unified control model. Based on the unified control model, an adaptive scheme is then developed in the presence of pure parametric uncertainty. The proposed controller guarantees asymptotic motion and force tracking without the need of extra conditions. Next, when considering external disturbances, control gains are designed by solving a linear matrix inequality (LMI) problem to achieve prescribed robust performance criterion. Indeed, arbitrary disturbance/parametric error attenuation with respect to both motion and force errors along with control input penalty are ensured in the L₂‐gain sense. Finally, applications are carried out on a two‐link constrained robot and two planar robots transporting a common object. Numerical simulation results show the expected performances. Copyright © 2006 John Wiley & Sons, Ltd.     

Transient performance improvement of model reference adaptive control: LMI‐based resetting

In this paper, a resetting mechanism is proposed to enhance the transient performance of model reference adaptive control. While the suggested method has a simple structure, it is capable of taking into account both the desired steady‐state behavior and the transient response, simultaneously. Whenever the transient specification is not satisfying, there is a jump in the controller parameters. This jump is determined by designing an optimal reset law. At the reset times, the after‐reset values of parameters are calculated based on a minimization problem. The considered cost function is a mixed H₂/H_∞ criterion, which minimizes the tracking error. The optimization problem is converted to an LMI formulation, and the reset law is designed by solving this LMI at certain reset times. To verify the effectiveness of the proposed approach, simulation results are presented.