Combustion and emissions performance of oxygenated fuels in a modern spark ignition engine

摘要

The combustion and emissions performance of oxygenated fuels has been investigated in a modern direct-injection spark-ignition (DISI) engine. In particular, the new biofuel candidate, 2,5-dimethylfuran, otherwise known as DMF, has been assessed as a future automotive fuel against ethanol, the most commercially accepted spark-ignition (SI) biofuel.ududWhen operating with DMF, the engine performance and emissions are less sensitive to changes in key control parameters than with gasoline. This allows a wider window for improving performance and/or reducing emissions. The relevance of modern injection strategies to increase performance or efficiency has also been assessed when using DMF. The use of split-injection at full load is shown to be less beneficial than with gasoline.ududNovel fuel preparation techniques have been investigated by comparing externally supplied gasoline-biofuel blends (conventional method) to internally mixed, dual-injection blends. This new mode presents an avenue for optimising oxygenated fuels with a low heat of vaporization, such as DMF and n-butanol; low blends with gasoline (≤25% by volume) are more efficiently utilised than in external blends. Furthermore, the particulate matter (PM) emissions can be reduced with dual-injection because gasoline is supplied through PFI.ududThe unlegislated emissions when using DMF have been benchmarked against gasoline and compared to other oxygenated fuels. In particular, the emissions of the major carbonyls are lower when using DMF compared to gasoline and even less so than ethanol, which heavily emits acetaldehyde and formaldehyde. The dual-injection mode further reduces the total carbonyl emissions when using DMF and ethanol blends compared to direct-injection (DI).