Analyse des performances et des émissions polluantes d'un moteur à allumage commandé à injection directe lors de l'utilisation de carburants oxygénés

Abstract

Direct injection is a promising technology that is becoming more popular in the automotive industry. This technology combined with the rising price of gasoline and the ever-dropping stock worldwide, the attention is starting to shift toward renewable biofuels. Therefore, the present research aimed at verifying the influence of various oxygenated fuels mixed with gasoline by asserting the importance of pollutant emissions and engine performances. Six oxygenated fuels were tested at volume percentages of 10, 20 and 40 % in gasoline in a direct injection spark ignition engine. Regarding the engine stability, all blends performed well. However, specific consumption for every mixture was increased linearly with the oxygen concentration. For all the tested fuels, the ignition delay dropped while the developed combustion time increased. Few variations were measured for CO and HC whereas NOx emissions were much lower with oxygenated blends than with gasoline. This drop in NOx emissions can be explained by a lower burnt gas temperature in the cylinder. As far as the particles are concerned, an important increase was measured for acetone while other fuels lowered their emissions. A brief study on sooting indexes (TSI, OESI, YSI, FESI, PMI) was completed and revealed the FESI as closest to the experimental data (without taking into account acetone). Although the FESI indicator was developed to show the effect of the chemical composition of fuels to create soot, further analysis had to be conducted to link this indicator with some physical properties of the fuels in order to follow the trends, even for the acetone. In order to do so, an optimization procedure using a genetic algorithm was used to find an equation representing experimental trends, including acetone this time. The lower heating value and the heat capacity at constant pressure were found to be two important properties influencing the particle production.

Date	1 May 2017
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Patrice Seers (Supervisor) & Romain Lemaire (Co-supervisor)