Évaluation de l'utilisation de carburants oxygénés sur un moteur à injection directe avec l'utilisation des modes d'injection homogène et stratifiée

Abstract

The introduction of direct injection spark ignition engines enables low fuel consumption. Moreover, this technique combined to the use of renewable fuels allows a reduction in the use of fossil fuels. Oxygenated fuels mostly used in a spark-ignition engine are ethanol and butanol. Butanol is more interesting due to its similarity to gasoline, but it is more expensive to produce. Then, using a mixture of acetone, butanol and ethanol (ABE) can be suitable because it is the result from the production of butanol by the fermentation way. In this context, this thesis will be mandated to characterize the effect of adding acetone in a mixture of ABE blended with gasoline in a direct injection engine in the homogeneous and stratified injection modes. To meet this mandate, an experimental study was conducted on a four-cylinder direct injection engine with mixtures of ethanol, butanol BE and ABE. The passage of the homogeneous to the stratified injection mode allows a reduction in specific fuel consumption by 5% fuel with gasoline. The oxygenated fuel addition has the effect of increasing the SFC, however this increase is lower in stratified injection mode. An increase in SFC was nevertheless noticed with the mixture 40% of ABE compared to other mixtures with oxygenated fuels. Little change in emissions of CO and HC was observed for the homogeneous injection mode. These emissions seem more sensitive to air-fuel ratio than oxygenated fuel concentration. In stratified mode injection, the oxygenated fuel concentration as well as the air-fuel ratio affect emissions of CO and NOX. The oxygenated fuel addition has the effect of increasing CO and reducing NOX emissions. The decrease in NOX is attributable to a lower adiabatic flame temperature, but also to an initial decrease in temperature of the air-fuel mixture when fuel is injected into the cylinder. For emissions of HC and PM, adding high fuel oxygen concentration has the effect of increasing these emissions. Possible causes of these increases are a result of the combustion of liquid fuel due to the presence of droplets in the air-fuel mixture and a fuel film on the piston crown during ignition. The influence of acetone in the mixture of ABE did not affect the results of pollutants.

Date	17 Nov 2015
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Patrice Seers (Supervisor)