Premixed compression-ignition (PCI) combustion techniques using low-cetane fuels, including Dieseline (mixture of diesel-gasoline) and naphtha, were investigated in a light-duty multi-cylinder CI-engine focusing mainly on reducing emissions while maintaining or improving the brake-thermal-efficiency. Different fuel-injection and intake/exhaust handling strategies were investigated in a wide engine operating load range from 1.4 to 17.3 bar BMEP. Moreover, an out-cylinder emission reduction technique through using a diesel-oxidation-catalyst (DOC) was investigated. Hot (uncooled) exhaust-gas-recirculation (EGR) combined with low fuel-injection-pressure (as low as 150 bar) significantly enhanced combustion-performance (COV < 5%) and reduced carbon-monoxide and hydrocarbon emissions at lower loads, when using low-cetane fuelled PCI techniques. At 1.4 to 6 bar BMEP, particulate emissions were reduced by >99% with respect to the diesel-CI baseline, in terms of number and mass, while maintaining brake-specific-NOx below 0.4 g/kWh. At loads more than 6 bar BMEP, double-injection strategy advanced combustion-phasing, where the first injection-event was shown to be significantly influential. Due to narrower boiling-range of naphtha compared to Dieseline, naphtha PCI resulted in high-COV at low loads, while it resulted in rapid-combustion at medium/high loads. Utilisation of the hot-EGR is a “win-win” strategy to enhance the combustion-process of the PCI-engine and reduction of the volatile/semi-volatile compounds using the DOC.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:699105 |
| Date | January 2016 |
| Creators | Zeraati Rezaei, Soheil |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.bham.ac.uk//id/eprint/7037/ |
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