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Interest is growing in the benefits of homogeneous charge compression ignition engines. In this paper, we investigate a novel approach to the development of a homogenous charge-like environment through the use of porous media. The primary purpose of the media is to enhance the spread as well as the evaporation process of the high pressure fuel spray to achieve charge homogenization. In this paper, we show through high speed visualizations of both cold and hot spray events, how porous media interactions can give rise to greater fuel air mixing and what role system pressure and temperature plays in further enhancing this process.

Résumé -Analyse de performance et caractéristiques de combustion du moteur HCCI avec les carburants similaires au gasoil -La technologie HCCI est considérée comme une solution prometteuse pour réduire les émissions de polluants, mais seuls quelques prototypes expérimentaux exploitent ce concept. Dans la combustion HCCI de DME et n-heptane, on distingue deux phases de réaction d'allumage, la première à plutôt basse température et la deuxième à haute température. La seconde est responsable de l'essentiel des pertes thermiques. Dans cette étude, un modèle adimensionnel et thermocinétique de combustion à une zone est développé. Le logiciel MATLAB est utilisé pour prédire les caractéristiques des moteurs HCCI utilisant deux types de carburants diesel : le dimethylether et le n-heptane. Les effets de la température et de la pression d'admission, de la prise en charge des carburants et de l'addition des gaz EGR sur les caractéristiques de l'auto-allumage l'optimum de la combution et les performances des moteurs HCCI ont été considérés. Abstract -Performance and Combustion Characteristics Analysis of HCCI Engine Operation with Diesel Like Fuels -HCCI is considered a very promising solution to reduce engine pollutant emissions, however so far only experimental prototypes have been inspired by this concept. HCCI combustion of both DME and n-heptane fuels display a distinct two-stage ignition reaction with the first

Use of dimethyl ether (DME) as a diesel fuel alternative has been increased due to the unique combustion characteristics of this oxygenated fuel. We have investigated performance and combustion characteristics of a naturally aspirated diesel engine using DME as the main fuel. In the experimental part of this work, OM314 direct-injection diesel engine was used as a base engine. A comprehensive full cycle was coupled with a multizone combustion model to simulate performance characteristics of the engine. Results of the volumetric efficiency showed that the highest brake torque was achievable in midspeed range. The power speed diagram showed that the brake torque tended to be much higher for diesel fuel than for DME when the engine speed was less than 1900 rpm. However, in engine speeds higher than 1900 rpm, brake torque in DME mode of operation was larger. Calculated emission results also suggested that negligible soot is produced in DME mode operation.