Effects of intake pressure on particle size and number emissions from premixed diesel low-temperature combustion

Abstract

In this study, 10 premixed diesel low-temperature combustion engine operating conditions were chosen based on engine intake pressure (1.2–1.6 bar), intake oxygen concentration (10%, 11%, and 12%), and injection timing (−24° after top dead centre in all test conditions). At each intake oxygen concentration, the effects of intake pressure on combustion parameters and emission measurements (carbon monoxide, hydrocarbons, nitrogen oxides, particulate matter mass concentration, and particle size distributions) were analyzed. Although increased intake pressure resulted in higher in-cylinder charge air density that improved fuel/air premixing and late-cycle oxidation quality, higher intake pressure also advanced the start of combustion and thereby decreased the time available for fuel and air premixing. But even with the decrease in premixing time available before start of combustion, increased intake pressure caused significant decreases in carbon monoxide, hydrocarbon, particulate matter mass, and particle num...