Speciation of Hydrocarbon and Carbonyl Emissions of 2,5-Dimethylfuran Combustion in a DISI Engine

It is known that species in the exhaust gas of automobile engines vary with fuel. As such, there is a need to understand the individual hydrocarbon (HC) and carbonyl (aldehydes and ketones) emissions from modern engines, especially as the use of alternative and renewable biofuels is set to rise. For gasoline, a promising candidate biofuel is 2,5-dimethylfuran (DMF). This work presents the key individual HCs that have been identified using gas chromatography mass spectrometry (GC/MS) and quantifies the emissions of 13 different carbonyls as specified by the California Air Resources Board (CARB) Method 1004 using high performance liquid chromatography (HPLC). The tests were conducted on a single cylinder direct-injection spark-ignition (DISI) engine at 1500 rpm, lambda = 1 and constant ignition timing. For the GC analysis, the midrange HCs were identified using the mass spectra. The results showed that unburned fuel (DMF) dominates the emissions. Other main emissions include cyclopentadiene, methyl vinyl ketone, 2-methylfuran, and aromatics. There was no evidence of the emissions of linear alkanes except methane. DMF produced the lowest overall carbonyl emissions compared with methanol, ethanol, n-butanol, and gasoline and, more importantly, the lowest emissions of formaldehyde.