Emissions suppression mechanism of premixed diesel combustion with variable valve timing

Y. Murata*, J. Kusaka, M. Odaka, Y. Daisho, D. Kawano, H. Suzuki, H. Ishii, Y. Goto

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


A variable valve timing (WT) mechanism is applied to achieve premixed diesel combustion at higher load for low emissions and high thermal efficiency in a light-duty diesel engine. By means of late intake valve closing (LIVC), compressed gas temperatures near the top dead centre are lowered, thereby preventing too early ignition and increasing ignition delay to enhance fuel-air mixing. The variability of an effective compression ratio has significant potential for ignition timing control of conventional diesel fuel mixtures. At the same time, the expansion ratio is kept constant to ensure thermal efficiency. Combining the control of LIVC, exhaust gas recirculation (EGR), supercharging systems, and high-pressure fuel injection equipment can simultaneously reduce NOx and smoke. The NOx and smoke suppression mechanism in the premixed diesel combustion is analysed using a three-dimensional computational fluid dynamics (3D-CFD) code combined with detailed chemistry. LIVC can achieve a significant NOx and smoke reduction due to lowering combustion temperatures and avoiding local overrich regions in the mixtures respectively.

Original languageEnglish
Pages (from-to)415-428
Number of pages14
JournalInternational Journal of Engine Research
Issue number5
Publication statusPublished - 2007 Dec 26


  • Diesel engine
  • Emission
  • KIVA3V
  • LIVC
  • Miller-PCCI
  • VVT

ASJC Scopus subject areas

  • Automotive Engineering
  • Aerospace Engineering
  • Ocean Engineering
  • Mechanical Engineering


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