IFAC-PapersOnLine 49-11 (2016) 361–368 ScienceDirect ScienceDirect Available online at www.sciencedirect.com 2405-8963 © 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. Peer review under responsibility of International Federation of Automatic Control. 10.1016/j.ifacol.2016.08.054 © 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. Keywords: HCCI, 0D model, EGR and ozone addition effect, combustion parameters (P max , CAD pmax , CA50), HCCI control, mathematical equation. 1. INTRODUCTION Due to the continual increase in fossil fuel consumption and the current focus on global warming, the automotive industry has the task to develop new engines with high efficiency. Among the proposed solutions, the Homogeneous Charge Compression Ignition (HCCI) offers an interesting compromise which is widely investigated. Combustion of HCCI engine offers gains in efficiency over traditional combustion concepts, and it is characterized by a very low level of Nitric Oxide (NO X ) and Particulate Matter (PM) emissions (Yao et al. 2009). Another advantage of HCCI engine is that it enables the use of a large range of fuels and additives. However, the challenge is to control the stability of combustion over the full range of engine operating points and during transition between two operating point. Combustion of HCCI engine process is strongly dependent to thermal, chemical and physical effects. So, many researchers have conducted in order to control cycle-to-cycle variations of the combustion through varying initial temperature of the mixture (Lü et al. 2005; Cinar et al. 2015), wall temperature (Komninos et al. 2015), intake pressure (Olsson et al. 2001), Variable Compression Ratio (VCR) (Christensen et al. 1999), Variable Valve Timing (VVT) (Gregory M Shaver et al. 2006; Prasad et al. 2013) but a fast response actuator is needed to manage transient operation and implementing these controls is complex and involves engine architecture modifications. Chemical effects are an efficient way to control this combustion using equivalence ratio, residual or rate of Exhaust Gas Recirculation (EGR) or incorporated additives in the mixture. As shown in (Jung et al. 2015), the slow response of the EGR actuator doesn’t allow to control cycle- to-cycle variations and can lead to three possibilities in the operating point behaviour: combustion, misfire or knock. The solution to compensate cycle-to-cycle variations is to combine dilution using EGR valve (slow response) and adding a proportion of additives in the mixture (fast response). Recently, the effect of ozone addition has been investigated experimentally (Foucher et al. 2013; Pinazzi et al. 2015) and it has been shown that the use of a small mass flow of ozone, a strong oxidizer species, can improve the combustion and forward the phasing of combustion. A flow of air is used to produce the ozone concentration through an ozone generator. This generator is working on the principle of a dielectric barrier discharge. During transitions between two operating points, the ozone addition can act like a chemical actuator to compensate cycle-to-cycle variation and improve the combustion over a wide range of operating points. The first step of this work towards the control of cycle-to- cycle combustion phasing is to develop a model that gives a good estimation and prediction of the combustion phasing using position of the EGR valve and ozone mass flow. Two main techniques are used in the context of combustion of HCCI engine modelisation: thermo-kinetic models and control-oriented models. Thermo-kinetic models depends on thermodynamical and chemical states within combustion chamber, such as the zero-dimensional Thermo-Kinetic Models (0D-TKM) of (Fiveland et al. 2000) and multi-zone models (Neshat et al. 2014). The accuracy of the multi-zone models to predict in-cylinder pressure and emissions levels depends on the initial imposed zones, decomposition of combustion chamber and interaction between zones. Abstract: The effect of ozone addition on combustion of Homogeneous Charge Compression Ignition (HCCI) engine was investigated to develop a 0D physical model of combustion and to propose a predictive static model of combustion parameters. All parameters of the physical model were identified using a single-cylinder fueled with iso-octane running at constant engine speed (1500rpm) and equivalence ratio (ϕ= 0.3) but various EGR rates and ozone rates. Experimental data were used to validate the physical model. Results show that the 0D combustion model yielded good results to capture combustion parameters like in-cylinder maximum pressure (P max ), corresponding angle (CAD pmax ) and the crank angle degree when 50% of the fuel had burned (CA50). All these parameter have been found strongly dependent on ozone addition and EGR rate. Then, mathematical equations were developped presented to describe the static relation between combustion parameters and both EGR rate and ozone addition. Laboratoire PRISME, Université d’Orléans, 8 rue Léonard de Vinci, 45072 Orléans Cedex 2, France, (e-mail :salim.sayssouk@etu.univ-orleans.fr) S. Sayssouk, D. Nelson-Gruel, C. Caillol, P. Higelin, Y. Chamaillard Towards control of HCCI combustion by ozone addition: a mathematical approach to estimate combustion parameters