Nonlinear Observer-Based Air-Fuel Ratio Control for Port Fuel Injected Wankel Engines

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The present work represents the continuation of the introductory study presented in part I [11] where the experimental plan, the measurement system and the tools developed for the testing of a modern Wankel engine were illustrated. In this paper the motored data coming from the subsequent stage of the testing are presented. The AIE 225CS Wankel rotary engine produced by Advanced Innovative Engineering UK, installed in the test cell of the University of Bath and equipped with pressure transducers selected for the particular application, has been preliminarily tested under motored conditions in order to validate the data acquisition software on the real application and the correct determination of the Top Dead Centre (TDC) location which is of foremost importance in the computation of parameters such as the indicated work and the combustion heat release when the engine is tested later under fired conditions. In this testing phase much importance has been given also to the measurement of the frictions at the different operating rotational speeds. Interestingly, the data have been collected at three different coolant temperatures, 30°C, 60°C and 90°C respectively, in order to investigate and quantify any possible effect and interaction of the heat transfer on the mechanical and thermodynamics engine parameters for the usual operating temperature range. The collected data are subsequently used for the determination of the Friction Mean Effective Pressure (FMEP) to be employed in the computation of the Brake Mean Effective Pressure (BMEP) from the indicated pressure cycle or in the numerical models created for simulation purposes. Finally, still by means of the analysis of the indicated pressure cycle, further considerations are drawn on the thermo-fluid dynamics interactions of the three moving chambers with the self-pressurizing air-cooled rotor system (SPARCS) with its details already described in the first part of this suite of papers.

Section: Introductionmentioning

confidence: 99%

Testing of a Modern Wankel Rotary Engine - Part II: Motoring Analysis

Vorraro

Turner

Brace

2022

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“…Within the University of Bath, the Institute for Advanced Automotive Propulsion Systems (IAAPS) established a fruitful co-operation with AIE UK where their 225CS rotary engine [16] has been experimentally tested and modelled through kinematic and computational fluid dynamics codes to make this machine Euro 6 complaint. Within the project, much effort was spent on innovative fuel control strategies to reduce the rotary's well-known appetite for fuel [17,18]. In addition, the several theoretical investigations supported by numerical activities proved that is possible to improve the emissions of Wankel rotary engines and successfully employ them as range extenders [19,20].…”

Section: Introductionmentioning

confidence: 99%

Testing of a Modern Wankel Rotary Engine - Part III: Firing Condition Analysis

Vorraro¹,

Turner²,

Akehurst³

2022

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This work represents a further contribution to reporting experimental activities carried out on a modern Wankel rotary engine. Specifically, in this study, the firing performance of the Advanced Innovative Engineering 225CS engine is analysed. Preliminary presentations of the experimental and measurement setup and a motoring analysis were extensively covered in Part I and II of this suite of papers while the current work presents the combustion analysis of the firing indicated pressure cycles collected through the bespoke combustion analyser software developed within the project. With the Wankel rotary engine gaining popularity again due to its potential as a range extender for battery electric vehicles, the aim of this work was mainly to analyse the fuel consumption together with the overall efficiency and the emissions at different engine speeds and loads as per classic steady-state engine testing. The characteristic curves of power and torque thus derived from the experimental measurements are reported while further deductions on combustion phenomena are then drawn from an analysis of the indicated pressure cycles. Specifically, parameters such as the rate of heat release, the net heat release, the IMEP and the indicated instantaneous torque are assessed. Further considerations are drawn on the overall mechanical efficiency relying on the IMEP computed from the indicated pressure cycles and the BMEP inferred from the torqued measured experimentally under steady-state conditions. Furthermore, the effects of the combustion on the internal pressure of the Self-Pressurizing Air-Rotor-Cooling System employed are evaluated in addition to parameters such as the Coefficient of Variation of the IMEP for the evaluation of the cycleto-cycle combustion quality and engine regularity. Finally, the postprocessed data represent an update to the historical literature on Wankel rotary engines. In addition, it can be used for the development and validation of numerical models for such engines hence allowing investigation by means of simulations of the effect on efficiency and performance of the rotary engine when employing alternative fuels such as hydrogen in the future.

“…An MVEM simulator for the AIE 225CS Wankel engine is established in Matlab/Simulink. The model is verified with the experimental data sets and the fuel injection model is integrated with a nonlinear observer-based air-fuel ratio controller (see our previous work [5] for details). The load torque in the simulator is a user-defined function of the engine speed.…”

Section: Eccentric Shaft Modelmentioning

confidence: 98%

“…The foundation of this section is the nonlinear Mean Value Engine Model (MVEM) developed by Hendricks [7,8] and our previous work [5,18]. There is a paucity of literature on dynamic modelling of the rotary engine.…”

Section: Mean Value Engine Modelmentioning

confidence: 99%

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Control-Oriented Modelling of a Wankel Rotary Engine: A Synthesis Approach of State Space and Neural Networks

Chen

Vorraro

Turner³

et al. 2020

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T he use of Wankel rotary engines as a range extender has been recognised as an appealing method to enhance the performance of Hybrid Electric Vehicles (HEV). They are effective alternatives to conventional reciprocating piston engines due to their considerable merits such as lightness, compactness, and higher power-to-weight ratio. However, further improvements on Wankel engines in terms of fuel economy and emissions are still needed. The objective of this work is to investigate the engine modelling methodology that is particularly suitable for the theoretical studies on Wankel engine dynamics and new control development.In this paper, control-oriented models are developed for a 225CS Wankel rotary engine produced by Advanced Innovative Engineering (AIE) UK Ltd. Through a synthesis approach that involves State Space (SS) principles and the artificial Neural Networks (NN), the Wankel engine models are derived by leveraging both first-principle knowledge and engine test data. We first re-investigate the classical physicsbased Mean Value Engine Model (MVEM). It consists of differential equations mixed with empirical static maps, which are inherently nonlinear and coupled. Therefore, we derive a SS formulation which introduces a compact control-oriented structure with low computational demand. It avoids the cumbersome structure of the MVEM and can further facilitate the advanced modern control design. On the other hand, via black-box system identification techniques, we compare the different NN architectures that are suitable for engine modelling using time-series test data: 1) the Multi-Layer Perceptron (MLP) feedforward network; 2) the Elman recurrent network; 3) the Nonlinear AutoRegressive with eXogenous inputs (NARX) recurrent network. The NN models overall tend to achieve higher accuracy than the MVEM and the SS model and do not require a priori knowledge of the underlying physics of the engine.