Low-temperature combustion within a HSDI diesel engine using multiple-injection strategies

Tiegang Fang, Robert E. Coverdill, Chia Fon F. Lee, Robert A. White

Research output: Contribution to journalArticlepeer-review


Low-temperature compression ignition combustion employing multiple-injection strategies in an optical high-speed direct injection diesel engine was investigated. Heat release characteristics were analyzed. The whole cycle combustion process was visualized by imaging the natural flame luminosity. The NOx emissions were measured in the exhaust pipe. The effects of the pilot injection timing, pilot fuel quantity, main injection timing, operating load, and injection pressure on the combustion and emissions were studied. Low-temperature combustion modes were achieved by using a small pilot injection with an injection timing much earlier than top dead center (TDC) followed by a main injection after TDC. The results were compared with conventional diesel (diffusion) combustion for comparison purposes. A premixed-combustion-dominated heat release rate pattern was seen for all the low-temperature combustion cases, while a typical diffusion flame combustion heat release rate was obtained for the conventional combustion case. A highly luminous flame was observed for the conventional combustion condition while a much less luminous flame was seen for the low-temperature combustion cases. For the higherload and lower injection pressure cases, liquid fuel being injected into low-temperature premixed flame was observed for certain cases. Compared with the conventional diffusion combustion, simultaneous reductions in soot and NOx were obtained for the lowtemperature combustion mode under similar operating loads. For high-load conditions, higher NOx emissions were obtained due to higher in-cylinder temperatures. However, compared with the conventional combustion case, a significant reduction in soot was achieved for the high-load conditions, which shows that increasing injection pressure greatly reduces soot emissions.

Original languageEnglish (US)
Article number062803
JournalJournal of Engineering for Gas Turbines and Power
Issue number6
StatePublished - Nov 2009


  • Combustion visualization
  • HCCI combustion
  • High-speed direct injection (HSDI) diesel engine
  • Low-temperature combustion

ASJC Scopus subject areas

  • Nuclear Energy and Engineering
  • Fuel Technology
  • Aerospace Engineering
  • Energy Engineering and Power Technology
  • Mechanical Engineering


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