HCCI engine modelling for control

Jia, Nan (2009) HCCI engine modelling for control. PhD thesis, University of Liverpool.

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Abstract

To meet future environmental challenges and more stringent emISSIOn legislation, Homogeneous Charge Compression Ignition (HCCI) has been proposed as a promising alternative to conventional combustion strategies. Heel engines offer thermal efficiencies comparable to those attained by high compression ratio diesel engines while maintaining the smoke free operation of spark ignition engines. HCel engines operate on the principle of having a premixed charge that auto-ignites and burns spontaneously throughout the cylinder as it is compressed by the piston. However, combustion control is a significant challenge for Heel engines that must be solved if they are to become a commercial success. In order to investigate the control strategies for solving the fundamental challenges, the original project specification set by the sponsor, Jaguar Cars Ltd, does not require that the models predict the HeCI combustion in every detailed aspect, but the models must be sufficient to capture most control relevant behaviours of HCCI process and are desired an inherent simple structure to reduce the simulation time. This thesis summarises research work in the development of HeCI engine models for control purposes. The work was initially inspired from the investigations of Heel research development that introduces the technologies to achieve Heel combustion and reviews the modelling approaches by different methodologies. The single-zone model was proposed and utilised with Arrhenius-type equations to describe the process of propane combustion. And then, gasoline fuelled HCCI engine was developed by utilising Wiebe function and using Genetic Algorisms (GAs) to identify unknown parameters in the combustion segments. The relevant simulation results show that the models are able to adequately simulate the combustion process and capture the combustion timing and in-cylinder pressure evolution. The aforementioned models were extended to investigate the general behaviours of the HCCI dynamic process, including cycle-to-cycle coupling, modulating the inducted gases composition and cyclic in-cylinder pressure evolutions. After the extensive simulation studies were conducted, a vehicle driveline model was then integrated into the model to investigate the feasible control strategy. By applying a simple proportional-integral controller, the vehicle velocity and engine output were both controlled by modulating intake and exhaust valves timing. The successful cycle-resolved simulation results indicate that the simplifications inherent in the model are not critical to the successful prediction of trend of ignition timing, work output variation and cyclic coupling - the most challenging problems of HCCI engines. Furthermore, the reduced complexity of the simulation offers the prospect of achieving simulation speeds that will allow real time predictions so that the model can be used as a practical engineering tool and a valuable testing facility In the development of suitable control strategies

Item Type:	Thesis (PhD)
Depositing User:	Symplectic Admin
Date Deposited:	20 Oct 2023 09:25
Last Modified:	20 Oct 2023 09:35
DOI:	10.17638/03174515
Copyright Statement:	Copyright © and Moral Rights for this thesis and any accompanying data (where applicable) are retained by the author and/or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3174515