Investigation of Boundary Layer Behaviour in HCCI Combustion using Chemiluminescence Imaging
Author
Summary, in English
A five-cylinder diesel engine, converted to a single
cylinder operated optical engine is run in Homogeneous
Charge Compression Ignition (HCCI) mode. A blend of
iso-octane and n-heptane is used as fuel.
An experimental study of the horizontal boundary layer
between the main combustion and the non-reacting
surface of the combustion chamber is conducted as a
function of speed, load, swirl and injection strategy. The
combustion behaviour is monitored by
chemiluminescence measurements.
For all cases an interval from -10 to 16 crank angles
after top dead center (CAD ATDC) in steps of one CAD
are studied. One image-intensified camera observes the
boundary layer up close from the side through a quartz
cylinder liner while a second camera has a more global
view from below to see more large scale structure of the
combustion.
The averaged chemiluminescence intensity from the
HCCI combustion is seen to scale well with the rate of
heat release. A boundary layer is defined and studied in
detail between the main combustion volume and the
piston crown surface as a function of crank angle. The
boundary layer is found to be in the range from 2 to 4
mm for all cases by the definition used; however, the
location for the measurements becomes more and more
important as combustion becomes more
inhomogeneous. To get accurate calculations, the level
of noise must also be considered and definitions of
boundary layer thickness should not be made at to low
chemiluminescence intensity.
cylinder operated optical engine is run in Homogeneous
Charge Compression Ignition (HCCI) mode. A blend of
iso-octane and n-heptane is used as fuel.
An experimental study of the horizontal boundary layer
between the main combustion and the non-reacting
surface of the combustion chamber is conducted as a
function of speed, load, swirl and injection strategy. The
combustion behaviour is monitored by
chemiluminescence measurements.
For all cases an interval from -10 to 16 crank angles
after top dead center (CAD ATDC) in steps of one CAD
are studied. One image-intensified camera observes the
boundary layer up close from the side through a quartz
cylinder liner while a second camera has a more global
view from below to see more large scale structure of the
combustion.
The averaged chemiluminescence intensity from the
HCCI combustion is seen to scale well with the rate of
heat release. A boundary layer is defined and studied in
detail between the main combustion volume and the
piston crown surface as a function of crank angle. The
boundary layer is found to be in the range from 2 to 4
mm for all cases by the definition used; however, the
location for the measurements becomes more and more
important as combustion becomes more
inhomogeneous. To get accurate calculations, the level
of noise must also be considered and definitions of
boundary layer thickness should not be made at to low
chemiluminescence intensity.
Department/s
Publishing year
2005
Language
English
Pages
1358-1369
Publication/Series
SAE Transactions, Journal of Fuels and Lubricants
Volume
114
Issue
4
Full text
Links
Document type
Journal article
Publisher
Society of Automotive Engineers
Topic
- Other Mechanical Engineering
Keywords
- Heat Release
- Boundary Layer
- Chemiluminescence
- Engine
- Combustion
- HCCI
Status
Published
ISBN/ISSN/Other
- ISSN: 0096-736X