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Conceptual model for the start of combustion timing in the range from RCCI to conventional dual fuel

Merts, Menno LU ; Fogué-Robles, Álvaro ; Monsalve-Serrano, Javier ; Garcia, Antonio ; Verhelst, Sebastian LU orcid and Lundgren, Marcus LU (2022) SAE World Congress Experience, WCX 2022
Abstract
In the challenge to reduce CO2, NOx and PM emissions, the application of natural gas or biogas in engines is a viable approach. In heavy duty and marine, either a conventional dual fuel (CDF), or a reactivity-controlled compression ignition (RCCI) approach is feasible on existing diesel engines. In both technologies a pilot diesel injection is used to ignite the premixed natural gas. However, the influence of injection-timing and -pressure on the start of combustion timing (SOC) is opposite between both modes. For a single operating point these relations can be explained by a detailed CFD simulation, but an intuitive overall explanation is lacking. This makes it difficult to incorporate both modes into one engine application, using a... (More)
In the challenge to reduce CO2, NOx and PM emissions, the application of natural gas or biogas in engines is a viable approach. In heavy duty and marine, either a conventional dual fuel (CDF), or a reactivity-controlled compression ignition (RCCI) approach is feasible on existing diesel engines. In both technologies a pilot diesel injection is used to ignite the premixed natural gas. However, the influence of injection-timing and -pressure on the start of combustion timing (SOC) is opposite between both modes. For a single operating point these relations can be explained by a detailed CFD simulation, but an intuitive overall explanation is lacking. This makes it difficult to incorporate both modes into one engine application, using a single controller. In an experimental campaign by the authors, on a medium speed engine, the lowest emissions were found to be very close to the SOC corresponding to the transition from RCCI to CDF. This highlights the relevance of having one overall control-scheme for the start of combustion. Principally the start of combustion boils down to having the required equivalence ratio (ϕ) and temperature (T). By using a 1D spray simulation the distribution of ϕ was investigated. Combined with a kinetic scheme and a thermodynamic engine analysis the earliest occurrence of an ignitable ϕ - T combination could be depicted. Graphically shown as an ignitability island during the engine cycle, this gives an intuitive prediction of SOC and its relationship with the start of injection (SOI), rail pressure, and air- and fuel-amount. It also shows the distinction between CDF and RCCI. For CDF the combustion starts when the ignitability island is approached from the rich side. For RCCI it is approached from the lean side. The described relationships could make it possible to incorporate both RCCI and CDF modes into one engine controller. (Less)
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author
; ; ; ; and
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
RCCI, Dual fuel, ICE, Pilot ignition, Engines
host publication
SAE Technical Papers
pages
12 pages
publisher
Society of Automotive Engineers
conference name
SAE World Congress Experience, WCX 2022
conference location
Detroit, United States
conference dates
2022-04-05 - 2022-04-07
external identifiers
  • scopus:85128099395
DOI
10.4271/2022-01-0468
language
English
LU publication?
yes
id
7fec269c-1654-44bc-a331-715965ea5b23
date added to LUP
2022-05-18 12:47:19
date last changed
2022-06-15 11:51:52
@inproceedings{7fec269c-1654-44bc-a331-715965ea5b23,
  abstract     = {{In the challenge to reduce CO2, NOx and PM emissions, the application of natural gas or biogas in engines is a viable approach. In heavy duty and marine, either a conventional dual fuel (CDF), or a reactivity-controlled compression ignition (RCCI) approach is feasible on existing diesel engines. In both technologies a pilot diesel injection is used to ignite the premixed natural gas. However, the influence of injection-timing and -pressure on the start of combustion timing (SOC) is opposite between both modes. For a single operating point these relations can be explained by a detailed CFD simulation, but an intuitive overall explanation is lacking. This makes it difficult to incorporate both modes into one engine application, using a single controller. In an experimental campaign by the authors, on a medium speed engine, the lowest emissions were found to be very close to the SOC corresponding to the transition from RCCI to CDF. This highlights the relevance of having one overall control-scheme for the start of combustion. Principally the start of combustion boils down to having the required equivalence ratio (ϕ) and temperature (T). By using a 1D spray simulation the distribution of ϕ was investigated. Combined with a kinetic scheme and a thermodynamic engine analysis the earliest occurrence of an ignitable ϕ - T combination could be depicted. Graphically shown as an ignitability island during the engine cycle, this gives an intuitive prediction of SOC and its relationship with the start of injection (SOI), rail pressure, and air- and fuel-amount. It also shows the distinction between CDF and RCCI. For CDF the combustion starts when the ignitability island is approached from the rich side. For RCCI it is approached from the lean side. The described relationships could make it possible to incorporate both RCCI and CDF modes into one engine controller.}},
  author       = {{Merts, Menno and Fogué-Robles, Álvaro and Monsalve-Serrano, Javier and Garcia, Antonio and Verhelst, Sebastian and Lundgren, Marcus}},
  booktitle    = {{SAE Technical Papers}},
  keywords     = {{RCCI; Dual fuel; ICE; Pilot ignition; Engines}},
  language     = {{eng}},
  month        = {{03}},
  publisher    = {{Society of Automotive Engineers}},
  title        = {{Conceptual model for the start of combustion timing in the range from RCCI to conventional dual fuel}},
  url          = {{http://dx.doi.org/10.4271/2022-01-0468}},
  doi          = {{10.4271/2022-01-0468}},
  year         = {{2022}},
}