Ethanol-Diesel Fumigation in a Multi-Cylinder Engine

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceeding

Abstract

Fumigation was studied in a 12 L six-cylinder heavy-duty engine. Port-injected ethanol was ignited with a small amount of diesel injected into the cylinder. The setup left much freedom for influencing the combustion process, and the aim of this study was to find operation modes that result in a combustion resembling that of a homogeneous charge compression ignition (HCCI) engine with high efficiency and low NOx emissions. Igniting the ethanol-air mixture using direct-injected diesel has attractive properties compared to traditional HCCI operation where the ethanol is ignited by pressure alone. No preheating of the mixture is required, and the amount of diesel injected can be used to control the heat release rate. The two fuel injection systems provide a larger flexibility in extending the HCCI operating range to low and high loads. It was shown that cylinder-to-cylinder variations present a considerable challenge for this type of combustion. By using closed-loop cylinder-individual control based on incylinder pressure sensors, combustion was successfully harmonized between the cylinders. Successful fumigation operation was verified up to 18.4 bar BMEP at a fixed engine speed of 1450 rpm. Two load points (4.6 bar BMEP and 9.2 bar BMEP) were studied in detail. Different diesel injection timings, diesel ratios, and EGR rates were investigated, and comparisons were drawn to pure diesel operation of the same engine. At medium load (9.2 bar BMEP), it was possible to obtain a stable HCCI-like combustion with low NOx emissions (0.1 g/kWh), reasonably high brake efficiency (37 %), and low pressure derivatives (5 bar/CAD). High load operation (18.4 bar BMEP) resulted in low pressure derivatives (5.5 bar/CAD), acceptable brake efficency (36 %), and relatively low NOx emissions (0.34 g/kWh).

Details

Authors
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Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Other Mechanical Engineering
  • Control Engineering

Keywords

  • HCCI, Combustion control, Fumigation
Original languageEnglish
Title of host publicationSAE technical paper 2008-01-0033
Publication statusPublished - 2008
Publication categoryResearch
Peer-reviewedYes
EventSAE World Congress 2008 - Detroit, Michigan, Detroit, MI, United States
Duration: 2008 Apr 142008 Apr 17

Conference

ConferenceSAE World Congress 2008
CountryUnited States
CityDetroit, MI
Period2008/04/142008/04/17

Related projects

Per Tunestål, Maria Henningsson & Rolf Johansson

Project: ResearchCollaboration with industry

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