Effect of post injections on mixture preparation and unburned hydrocarbon emissions in a heavy-duty diesel engine

Jacqueline Antonia O'Connor, Mark P.B. Musculus, Lyle M. Pickett

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

This work explores the mechanisms by which a post injection can reduce unburned hydrocarbon (UHC) emissions in heavy-duty diesel engines operating at low-temperature combustion conditions. Post injections, small, close-coupled injections of fuel after the main injection, have been shown to reduce UHC in the authors' previous work. In this work, we analyze optical data from laser-induced fluorescence of both CH2O and OH and use chemical reactor modeling to better understand the mechanism by which post injections reduce UHC emissions. The results indicate that post-injection efficacy, or the extent to which a post injection reduces UHC emissions, is a strong function of the cylinder pressure variation during the post injection. However, the data and analysis indicate that the pressure and temperature rise from the post injection combustion cannot solely explain the UHC reduction measured by both engine-out and optical diagnostics. The fluid-mechanic, thermal, and chemical interaction of the post injection with the main-injection mixture is a key part of UHC reduction; the starting action of the post jet and the subsequent entrainment of surrounding gases are likely both important processes in reducing UHC with a post injection.

Original languageEnglish (US)
Pages (from-to)111-123
Number of pages13
JournalCombustion and Flame
Volume170
DOIs
StatePublished - Aug 1 2016

Fingerprint

diesel engines
Hydrocarbons
Diesel engines
hydrocarbons
injection
preparation
Air entrainment
Chemical reactors
Fluid mechanics
Engine cylinders
chemical reactors
Gases
Fluorescence
Engines
fluid mechanics
entrainment
Temperature
Lasers
laser induced fluorescence
engines

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Physics and Astronomy(all)

Cite this

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abstract = "This work explores the mechanisms by which a post injection can reduce unburned hydrocarbon (UHC) emissions in heavy-duty diesel engines operating at low-temperature combustion conditions. Post injections, small, close-coupled injections of fuel after the main injection, have been shown to reduce UHC in the authors' previous work. In this work, we analyze optical data from laser-induced fluorescence of both CH2O and OH and use chemical reactor modeling to better understand the mechanism by which post injections reduce UHC emissions. The results indicate that post-injection efficacy, or the extent to which a post injection reduces UHC emissions, is a strong function of the cylinder pressure variation during the post injection. However, the data and analysis indicate that the pressure and temperature rise from the post injection combustion cannot solely explain the UHC reduction measured by both engine-out and optical diagnostics. The fluid-mechanic, thermal, and chemical interaction of the post injection with the main-injection mixture is a key part of UHC reduction; the starting action of the post jet and the subsequent entrainment of surrounding gases are likely both important processes in reducing UHC with a post injection.",
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Effect of post injections on mixture preparation and unburned hydrocarbon emissions in a heavy-duty diesel engine. / O'Connor, Jacqueline Antonia; Musculus, Mark P.B.; Pickett, Lyle M.

In: Combustion and Flame, Vol. 170, 01.08.2016, p. 111-123.

Research output: Contribution to journalArticle

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