Emissions reduction effects of diesel combustion with low compression and high expansion ratios

Yutaka Murata*, Jin Kusaka, Yasuhiro Daisho, Daisuke Kawano, Hisakazu Suzuki, Hajime Ishii, Yuichi Goto

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


For suppressing NOx and smoke simultaneously, an alternative diesel combustion strategy is required to avoid local over-rich regions in the mixtures at EGR conditions. In the present study, a variable valve timing (VVT) mechanism is applied in a light duty HSDI diesel engine. By means of lowering effective compression ratios, compressed gas temperatures near the top dead center are lowered, thereby preventing too early ignition and increasing ignition delay to enhance fuel-air mixing. At the same time, the expansion ratio is kept constant to ensure thermal efficiency. It is recognized that the optimum control of EGR and effective compression ratios can simultaneously reduce NOx and smoke.

Original languageEnglish
Pages (from-to)1442-1447
Number of pages6
JournalNihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B
Issue number7
Publication statusPublished - 2007 Jul
Externally publishedYes


  • Combustion
  • Common rail
  • Diesel engine
  • EGR
  • Emission
  • Fuel injection
  • HPLI
  • LIVC
  • Low effective compression ratio

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering


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