A Modular Approach for Diesel Engine Air Path Control Based on Nonlinear MPC

Hänggi, Severin; Frey, Jonathan; Dooren, Stijn van; Diehl, Moritz; Onder, Christopher H.

doi:10.1109/tcst.2022.3228203

Cited by 5 publications

(5 citation statements)

References 39 publications

(62 reference statements)

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“…Where A AP is system matrix, B AP is control matrix, C AP is output matrix, and D AP is feed-forward matrix. The discrete time step is represented as k. The perturbed state, input, and output vectors are given in equation (11).…”

Section: Low-level Controller: Air Path Predictive Controllermentioning

confidence: 99%

“…A calibration intensive explicit formulation was avoided by using a linearized plant model with fast sampling rate. In Hanggi et al, 11 a nonlinear model predictive controller was used for the airpath control with gray box models. The references for the airpath were predefined, however in the current work presented in this paper the references for the airpath were calculated online by a high-level nonlinear MPC controller and the references are tracked by a low-level linear MPC controller with emission constraints.…”

Section: Introductionmentioning

confidence: 99%

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Hierarchical multi-time-scale predictive thermal management and fuel optimization for heavy-duty compression ignition engines

Duraiarasan

Salehi

Mahesh

et al. 2023

International Journal of Engine Research

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For heavy-duty diesel engines, NOX emissions reduction is strongly constrained by fuel efficiency. This paper presents a hierarchical model predictive controller (H-MPC) for coordinated control of tailpipe NOX emissions and fuel consumption. The H-MPC uses the separation of slow and fast dynamics that exist in the engine and its aftertreatment system. The controller is synthesized with an architecture in which a high-level MPC uses a longer prediction horizon compared to the low-level predictive controller which tracks the high-level controller command and manages the thermal dynamics of the aftertreatment system. Engine load preview enables the high-level controller to estimate the desired catalyst temperature ahead of time and addresses the selective catalytic reduction (SCR) slow thermal dynamics. Calculated by the high-level controller, the intake manifold pressure, and the start of injection (SOI) crank angle is used as reference trajectories in the low-level controller that regulates fast dynamical behaviors such as engine out NOX emissions. Hardware-in-the-loop (HIL) validation of this integrated H-MPC on a rapid prototype controller shows that when the SCR catalyst temperature is above light-off temperature (warmed-up condition), the engine operation is shifted to operate with the best fuel economy since the warmed-up SCR can efficiently reduce the engine-out NOX emissions. Results indicate that up to 0.8% benefit in cycle averaged BSFC along with a 13% reduction in tailpipe NOX compared to a stock engine calibration can be achieved with the coordinated engine and aftertreatment system through H-MPC.

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Section: Low-level Controller: Air Path Predictive Controllermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hierarchical multi-time-scale predictive thermal management and fuel optimization for heavy-duty compression ignition engines

Duraiarasan

Salehi

Mahesh

et al. 2023

International Journal of Engine Research

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“…The air path is modeled by an existing mean-value model which has already been validated. 39 Other forms of air-path models can be used as long as the interactions to the cylinder model remain unchanged. For the layout of engine A, previous analyses showed no advantages for a steady-state optimization of HP EGR when compared to LP EGR.…”

Section: Process Modelmentioning

confidence: 99%

“…For the layout of engine A, previous analyses showed no advantages for a steady-state optimization of HP EGR when compared to LP EGR. 39 Therefore, HP EGR is neglected in the analysis below.…”

Section: Process Modelmentioning

confidence: 99%

“…Our contribution is threefold: First, we propose a cycle-discrete model based on first principles that describes the charge, combustion, and discharge of an engine cylinder with negative valve overlap. We integrate the cylinder model into an existing air path model 39 to simulate the complete engine as a mean-value model. Second, the model proposed is able to simulate various VVT strategies, such as early IVC (Miller cycle), early EVO, and cylinder deactivation.…”

Section: Introductionmentioning

confidence: 99%

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A method to quantify the advantages of a variable valve train for CI engines

Moretto,

Hänggi,

Omanovic

et al. 2023

International Journal of Engine Research

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Today’s CI engines are subject to strict regulations of pollutant emissions and ambitious fuel consumption targets. Therefore, the interaction between the engine and the exhaust aftertreatment system (ATS) has become increasingly important. Numerous studies have shown that a variable valve train (VVT) improves the interaction between engine and ATS. However, most of these studies either quantify the advantage on a specific engine or only present complex CFD models, such that the results are not easily transferable to different engines. Thus, engine manufacturers cannot directly use these results to assess the advantage of various VVT strategies for their engines. In this paper, we propose a cycle-discrete cylinder model based on first principles which allows to simulate various VVT strategies. In contrast to present methods based on CFD, the proposed cylinder model can be realized with the equations presented. Furthermore, the model is identified with measurement data of an engine without a VVT. A separate engine, which is retrofitted with a fully VVT, is used to validate the proposed modeling approach. Using the identified model in combination with a mean-value model of the air path, we are able to simulate the effects of early intake valve closing, early exhaust valve opening, and cylinder deactivation for a complete CI engine that has no VVT installed. The model is then used to highlight the advantage of a VVT for two scenarios at part-load operation. At cold start, where the temperature of the ATS must be increased quickly, variable valve timing achieves higher enthalpy flows to the ATS while also lowering engine-out NOx emissions when compared to a standard engine strategy. If the ATS is at the operating temperature, cylinder deactivation achieves significantly higher enthalpy flows which prevents the ATS from cooling down. In addition, cylinder deactivation also lowers fuel consumption and engine-out NOx emissions.

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