An ammonia coverage ratio observing and tracking controller: stability analysis and simulation evaluation

Zhao, Jinghua; Gong, Xun; Hu, Yunfeng; Gao, Jinwu; Chen, Hong

doi:10.1007/s11432-018-9638-7

Cited by 5 publications

(10 citation statements)

References 29 publications

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“…The chemical reaction modeling process, as described in the literature [9], is based on the assumption that the catalyst is a continuously stirred tank reactor (CSTR) and that all the species in the catalyst (reactor) are homogeneous. Based on the assumption and the mass balance and heat balance, the ordinary differential equations (ODEs) of the 1-cell urea-SCR catalyst dynamic model can be described as (4), as shown at the bottom of the next page, where the parameters are defined as (5), as shown at the bottom of the next page.…”

Section: Control-oriented Urea-scr System Modelmentioning

confidence: 99%

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Sequential Optimization of Eco-Driving Taking Into Account Fuel Economy and Emissions

Zhao

Gao

2019

IEEE Access

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The regulations for diesel vehicles are expected to become increasingly more stringent. However, how to coordinate eco-driving, the diesel engine and the urea selective catalytic reduction (urea-SCR) system for fuel economy improvement and emissions reduction remains a formidable challenge. In this paper, a sequential optimization control method with three stages is designed. In stage I, the optimal driving force and braking force are obtained by solving a nonlinear optimization problem of tracking the vehicle velocity profile. In stage II, a real-time reference estimation model is designed to provide the optimal ammonia coverage ratio target. In stage III, to implement the driving force requirement and ammonia coverage ratio target, an integrated engine and urea-SCR system control method and a distributed method are proposed, respectively. The distributed method consists of a fuel injection controller utilizing a data-driven predictive method and a NH 3 dosing controller utilizing nonlinear model predictive control (NMPC). The control model of the integrated method is represented by the first-order ammonia coverage ratio dynamics only. The results show that the fuel consumption is improved by 5.3% and the PM emission is reduced by 11.56% during the partial transient acceleration process, and that the fuel consumption and emissions of the integrated control method can accomplish the level of the distributed method and achieve the trade-off between the multi-objective. However, the integrated control method incurs an average computational time penalty of 15.47%. INDEX TERMS Diesel vehicles, urea selective catalytic reduction (urea-SCR) system, sequential optimization, nonlinear model predictive control (NMPC), Pontryagin's minimum principle (PMP).

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Section: Control-oriented Urea-scr System Modelmentioning

confidence: 99%

“…The associate editor coordinating the review of this manuscript and approving it for publication was Yue Cao. sufficient to satisfy the increasingly stringent regulations for NO x emission [4]. Thus, some out-cylinder aftertreatment systems have been added to diesel vehicles to improve fuel economy and reduce emissions.…”

Section: Introductionmentioning

confidence: 99%

Sequential Optimization of Eco-Driving Taking Into Account Fuel Economy and Emissions

Zhao

Gao

2019

IEEE Access

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“…Selective catalytic reduction (SCR) systems are the most promising aftertreatment technologies for reducing the NO x emission [1]. The working principle of SCR systems is that NO x exhausted by engines can be reduced by ammonia ( 3 NH ) generated from a 32.5% aqueous urea solution (AdBlue), and the excess 3 NH is also a harmful emission [2].…”

Section: Introductionmentioning

confidence: 99%

Data-Driven Predictive Control With Switched Subspace Matrices for an SCR System

et al. 2022

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Selective catalytic reduction (SCR) systems are distributed systems with strong timevarying parameter characteristics such that an accurate model for it is difficult to establish. Its control task simultaneously achieving high NO x conversion efficiency and low 3 NH slip is a typical multi-objective and multi-constraint problem, which is suitable to be solved in the framework of the model predictive control (MPC). However, how to find a data-driven identification method based on the dynamic characteristics of an SCR system and a corresponding MPC method for satisfying its emission requirements remain a formidable challenge. The sufficient identification for the traditional identification method with fixed subspace model requires an excessively high order subspace matrix, such that a degradation in real-time performance is caused and the generality of the method under non-identification conditions is limited. In this paper, utilizing the transient data of the SCR system under the WHTC cycle, a novel identification method for some lower order subspace matrices excited by the segmented data referring to the dynamic of the ammonia coverage ratio is established. A corresponding predictive controller with the switched subspace matrices according to working conditions is designed in order to further improve its real-time performance, generality and robustness. The simulation results show that under the identification condition the proposed predictive controller compared to the traditional method can improve the emissions of NO x and 3 NH , that under the non-identification condition the proposed predictive controller can also improve the emissions and its optimization effects have better robustness to uncertainties of the transient cycle, and that the proposed predictive controller saves an significant computation time.

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“…6 However, N O x sensors have significant ammonia cross-sensitivity pushing up their readings, so that control systems cannot obtain accurate N O x concentration. 7 How to utilize the N O x sensor readings and control-oriented model to effectively estimate the N O x concentration, the N H 3 concentration and θ N H 3 remains a further challenge. In practical engineering implements of the China/EURO VI regulations, the engine emissions of N H 3 and N O x are very low in most operating conditions.…”

Section: Introductionmentioning

confidence: 99%

Design of extended Kalman filter observer coupled to ammonia cross-sensitivity model for an SCR system

Zhao

Zhang

Wang

et al. 2022

International Journal of Engine Research

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Commercial diesel vehicles that comply the China/EURO VI emission regulations are generally equipped with selective catalytic reduction (SCR) systems for reducing [Formula: see text] emission and [Formula: see text] sensors at its downstream for accurate closed-loop control. However, [Formula: see text] sensors have significant ammonia cross-sensitivity pushing up their readings. Moreover, for the closed-loop control of SCR systems effectively estimating the critical states from the [Formula: see text] sensor readings remains a further challenge. In this paper, an ammonia cross-sensitivity model with segmented sin and quadratic composite functions describing high frequency characteristics is established by analyzing the experimental data of an SCR system. A control-oriented three-states model of an SCR system is established, and based on it an extended Kalman filter (EKF) observer coupled to the ammonia cross-sensitivity model is proposed. The simulation results show that from the [Formula: see text] sensor readings the EKF observer can effectively estimate the deterioration trend of the [Formula: see text] and [Formula: see text] emissions, and describe the dynamic change process of the ammonia coverage rate. The experimental results under the four non-excitation cycles show that the EKF observer can effectively estimate the deterioration trend, that the average estimated accuracy of [Formula: see text] and [Formula: see text] during their deterioration stage can respectively reach 86.16% and 54.87%, and that the observer has better robustness to disturbances from the operating conditions.

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An ammonia coverage ratio observing and tracking controller: stability analysis and simulation evaluation

Cited by 5 publications

References 29 publications

Sequential Optimization of Eco-Driving Taking Into Account Fuel Economy and Emissions

Sequential Optimization of Eco-Driving Taking Into Account Fuel Economy and Emissions

Data-Driven Predictive Control With Switched Subspace Matrices for an SCR System

Design of extended Kalman filter observer coupled to ammonia cross-sensitivity model for an SCR system

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