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Cylinder to cylinder variation related to gas injection timing on a dual-fuel engine

Merts, Menno LU ; Pet, Quintin ; Mesman, Peter and Verhelst, Sebastian LU (2019) SAE World Congress Experience, WCX 2019 In SAE Technical Papers 2019.
Abstract

The natural gas/diesel dual-fuel engine is an interesting technique to reduce greenhouse gas emission. A limitation of this concept is the emission of un-combusted methane. In this study we analyzed the influence of PFI gas-injection timing on cylinder to cylinder gas-distribution, and the resulting methane emissions. This was done on a 6 cylinder HD engine test bench and in a GT-power simulation of the same engine. The main variable in all tests was the timing of the intake port gas injection, placed either before, after, or during the intake stroke. It showed that injecting outside of the intake window resulted in significant variation of the amount of trapped gaseous fuel over the 6 cylinders, having a strong impact on methane... (More)

The natural gas/diesel dual-fuel engine is an interesting technique to reduce greenhouse gas emission. A limitation of this concept is the emission of un-combusted methane. In this study we analyzed the influence of PFI gas-injection timing on cylinder to cylinder gas-distribution, and the resulting methane emissions. This was done on a 6 cylinder HD engine test bench and in a GT-power simulation of the same engine. The main variable in all tests was the timing of the intake port gas injection, placed either before, after, or during the intake stroke. It showed that injecting outside of the intake window resulted in significant variation of the amount of trapped gaseous fuel over the 6 cylinders, having a strong impact on methane emissions. Injecting outside of the intake stroke results in gas awaiting in the intake port. Both testing and simulation made clear that as a result of this, cylinder 1 leans out and cylinder 6 enriches. The simulation showed how this is caused by the airflow into the manifold, which enters the manifold close to cylinder 1. This flow picks up gas residing before the first cylinders, and distributes it over the cylinders further downstream. The richer cylinders have a higher absolute methane emission. By calculating the ratio between trapped and emitted methane, we found operating points where the enrichment caused by unequal gas distribution led to lower relative methane emission. This can be attributed to the better combustibility of methane under richer conditions. Although the injection timing was placed outside the intake window on purpose in our experiments, the same distribution problem occurs in situations where the gas injection is longer than the intake stroke. This is a common situation with currently available dual-fuel systems. The solution can be found in a gas injection system with significantly higher capacity.

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Please use this url to cite or link to this publication:
author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
host publication
Technical Paper - WCX SAE World Congress Experience
series title
SAE Technical Papers
volume
2019
article number
2019-01-1162
publisher
Society of Automotive Engineers
conference name
SAE World Congress Experience, WCX 2019
conference location
Detroit, United States
conference dates
2019-04-09 - 2019-04-11
external identifiers
  • scopus:85064641115
ISSN
0148-7191
DOI
10.4271/2019-01-1162
language
English
LU publication?
yes
id
cd7dcfbd-2379-438e-a53c-7fdb5e06088e
date added to LUP
2019-05-03 12:39:00
date last changed
2020-01-13 01:42:42
@inproceedings{cd7dcfbd-2379-438e-a53c-7fdb5e06088e,
  abstract     = {<p>The natural gas/diesel dual-fuel engine is an interesting technique to reduce greenhouse gas emission. A limitation of this concept is the emission of un-combusted methane. In this study we analyzed the influence of PFI gas-injection timing on cylinder to cylinder gas-distribution, and the resulting methane emissions. This was done on a 6 cylinder HD engine test bench and in a GT-power simulation of the same engine. The main variable in all tests was the timing of the intake port gas injection, placed either before, after, or during the intake stroke. It showed that injecting outside of the intake window resulted in significant variation of the amount of trapped gaseous fuel over the 6 cylinders, having a strong impact on methane emissions. Injecting outside of the intake stroke results in gas awaiting in the intake port. Both testing and simulation made clear that as a result of this, cylinder 1 leans out and cylinder 6 enriches. The simulation showed how this is caused by the airflow into the manifold, which enters the manifold close to cylinder 1. This flow picks up gas residing before the first cylinders, and distributes it over the cylinders further downstream. The richer cylinders have a higher absolute methane emission. By calculating the ratio between trapped and emitted methane, we found operating points where the enrichment caused by unequal gas distribution led to lower relative methane emission. This can be attributed to the better combustibility of methane under richer conditions. Although the injection timing was placed outside the intake window on purpose in our experiments, the same distribution problem occurs in situations where the gas injection is longer than the intake stroke. This is a common situation with currently available dual-fuel systems. The solution can be found in a gas injection system with significantly higher capacity.</p>},
  author       = {Merts, Menno and Pet, Quintin and Mesman, Peter and Verhelst, Sebastian},
  booktitle    = {Technical Paper -  WCX SAE World Congress Experience },
  issn         = {0148-7191},
  language     = {eng},
  month        = {04},
  publisher    = {Society of Automotive Engineers},
  series       = {SAE Technical Papers},
  title        = {Cylinder to cylinder variation related to gas injection timing on a dual-fuel engine},
  url          = {http://dx.doi.org/10.4271/2019-01-1162},
  doi          = {10.4271/2019-01-1162},
  volume       = {2019},
  year         = {2019},
}