Combustion and exhaust emissions in a direct-injection diesel engine dual-fueled with natural gas

Yasuhiro Daisho*, Toru Yaeo, Takahisa Koseki, Takeshi Saito, Ryoji Kihara, Edwin N. Quiros

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

67 Citations (Scopus)


Dual-fuel operation of a direct-injection diesel engine with natural gas fuel can yield a high thermal efficiency almost comparable to the diesel operation at higher loads. The dual-fuel operation, however, at lower loads inevitably suffers from lower thermal efficiency and higher unburned fuel. To improve this problem, engine tests were carried out on a variety of engine parameters including diesel fuel injection timing advance, intake throttling and hot and cooled exhaust gas recirculation (EGR). It was found that diesel injection timing advance gave little improvement in thermal efficiency and increased NOx. Intake throttling promoted better combustion and shortened its duration with a consequent improvement in efficiency at higher natural gas fractions. Hot EGR raised thermal efficiency, reduced smoke levels, and maintained low NOx levels. Cooled EGR reduced NOx emissions but lowered thermal efficiency. The use of hot EGR is considered to be the best means to improve diesel engine dual-fuel operation with natural gas at low loads.

Original languageEnglish
Title of host publicationSAE Technical Papers
Publication statusPublished - 1995
Event1995 SAE International Congress and Exposition - Detroit, MI
Duration: 1995 Feb 271995 Mar 2


Other1995 SAE International Congress and Exposition
CityDetroit, MI

ASJC Scopus subject areas

  • Automotive Engineering
  • Safety, Risk, Reliability and Quality
  • Pollution
  • Industrial and Manufacturing Engineering


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