Title: Controls-oriented modelling and LQR control of natural gas HCCI engines

Authors: Marwa AbdelGawad; Reza Tafreshi; Reza Langari

Addresses: Texas A&M Engineering Building, Education City, P.O. Box 23874, Doha, Qatar ' Texas A&M Engineering Building, Education City, P.O. Box 23874, Doha, Qatar ' Texas A&M University, College Station, TX 77843-3123, USA

Abstract: Homogeneous charge compression ignition (HCCI) engines have been proposed as a solution to designing efficient engines that follow emission regulations set by the US Environmental Protection Agency. The main idea behind HCCI engines is to combust a lean, homogeneous air-fuel mixture using compression. However, due to the fact that HCCI combustion is triggered by auto-ignition of the mixture during compression, there is no direct method of controlling combustion timing to ensure maximum efficiency. Therefore, the goal of this paper is to develop a control strategy for ignition timing of natural gas HCCI engines at steady-state conditions. To model the engine, a controls-oriented model is developed based on the modified knock integral model and is validated using a model developed by GT-power. Furthermore, a linear quadratic regulator is designed to control the engine timing. Simulation results show that the control system can track engine timing within 0.5% of its target value.

Keywords: homogeneous charge compression ignition; HCCI engines; linear quadratic regulator; LQR; natural gas; control models; modelling; emission regulations; vehicle emissions; combustion timing control; ignition timing control; engine timing control; simulation.

DOI: 10.1504/IJVP.2013.058281

International Journal of Vehicle Performance, 2013 Vol.1 No.2, pp.205 - 234

Received: 03 Aug 2012
Accepted: 18 Mar 2013
Published online: 12 Jul 2014 *

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