Higher heat release rate in the combustion of emulsified fuel reduces Pmax and allows it to be adjusted to further increase combustion efficiency.

  • Time 
    01/24/2017 - 15:00-01/24/2017 - 17:00
  • Theme 
  • Authors

    Jerry Ng
    (F.IMarEST, M.SNAME, M.IMechE, M.IEEE, M.SME, C.Eng)
    Kaisa Honkanen
    (AM.IMarest, AM.SNAME)
Jerry Ng

The primary interest in emulsified fuel technology has been focused on the reduction of NOx and particulate matter emissions. Although some work have been done to study the benefit of emulsified fuel technology in improving combustion efficiency, most investigations have been carrried out on older engines using the mechanical Woodward governor.  Typical fuel savings of between 2-5% have been reported. The authors have recently installed several emulsified fuel systems on ocean going vessels (such as container liners, tankers and car carriers) powered by slow speed engines. The combustion processes in the engines were monitored and recorded on line using pressure transducers. Results of pressure-volume, pressure-crank angle, scavange pressure, Pmax and Pmep were investigated. It was found that the higher heat release rate due to the combustion of emulsified fuel caused Pmax to be reduced, a phenomenal which had been observed in other previous emulsified fuel research. This presented the practical opportunity to adjust the Pmax back to the designed higher Pmax of the engine, and thus improve the fuel efficiency (g/kWh) of the engine further, particulartly at higher loads. This is a significant finding because it enables the fuel efficiency of diesel engines to be improved much more than just by burning emulsified fuel or just by maximsing Pmax (or auto-tuning) alone. It enables a significant and practical method to improve the fuel efficiency of diesel engines beyond their maximum designed test bed fuel efficiency.