Effects of Prechamber on Efficiency Improvement and Emissions Reduction of a SI Engine Fuelled with Gasoline and CNG 2019-24-0236
The permanent aim of the automotive industry is the further improvement of the engine efficiency and the simultaneous pollutant emissions reduction.
The aim of the study was the optimization of the gasoline and compressed natural gas (CNG) combustion by means of a passive prechamber. This analysis allowed the improvement of the engine efficiency in lean-burn operation condition too. The investigation was carried out in an real small Spark Ignition (SI) engine fueled with Gasoline and CNG and equipped with a proper designed passive prechamber.
In particular, Gasoline and CNG were used to analyze the effects of the prechamber on engine performance and associated pollutant emissions. Indicated Mean Effective Pressure, Heat Release Rate and Mass Burned Fraction were used to evaluate the effects on engine performance. Gaseous emissions were measured as well. Particulate Mass, Number and Size Distributions were analyzed. Emissions samples were taken from the exhaust flow, just downstream of the valves. Opacity was measured downstream the Three-Way Catalyst. Three different engine speeds were investigated, namely 2000, 3000 and 4000 rpm. Stoichiometric and lean condition at full load were considered in all tests. The results were compared with those obtained with the engine equipped with the standard spark plug and the same compression ratio. The results indicated that both performance and emissions were strongly influenced by the prechamber.
Paolo Sementa, Francesco Catapano, SILVANA Di Iorio, Bianca Maria Vaglieco