Optimization of pilot injection pattern and its effect on diesel combustion with high-pressure injection

Kiyomi Nakakita, Teruaki Kondoh, Katsuyuki Ohsawa, Takeshi Takahashi, Satoshi Watanabe

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


The pilot injection pattern was optimized and some effects of pilot injection on combustion and exhaust emissions were investigated using a single-cylinder DI diesel engine. (1) In order to avoid the increase of smoke, both a small-hole nozzle and very accurate control of pilot injection quantity and pilot-main interval are essential. These improve the atomization of the pilot fuel and the air entrainment into the main spray. (2) With pilot injection. NOx is not reduced at injection timing of TDC but is gradually reduced at more retarded injection timing. This is because the main combustion is accelerated at early injection timing but is decelerated at retarded injection timing, due to the promotion of ignition. (3) With pilot injection, the effect of NOx reduction is generally small but the prevention of HC increase is obtained only under light-load, injection timing retard conditions.

Original languageEnglish
Pages (from-to)892-898
Number of pages7
JournalTransactions of the Japan Society of Mechanical Engineers Series B
Issue number559
Publication statusPublished - 1993
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanical Engineering


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