A Novel Combustion Chamber to Physically Stratify the Charge in a
Gasoline Direct Injection Engine 03-16-03-0016
This also appears in
SAE International Journal of Engines-V132-3EJ
Realizing the potential of the gasoline direct injection (GDI) concept lies in
effectively stratifying the charge at different engine operating conditions.
This is generally obtained by properly directing the air and fuel through
carefully oriented intake port(s) and fuel spray and appropriately changing
injection parameters. However, robust methods of charge stratification are
essential to extend the lean operating range, particularly in small GDI engines.
In this work, a novel piston shape was developed for a 200 cm3,
single-cylinder, four-stroke gasoline engine to attain charge stratification.
Stratification of charge is achieved even when the fuel was injected early in
the intake stroke by a specially shaped wedge on the piston crown that produced
twin vortices during compression and physically separated the charge into two
sides in the combustion chamber. Computational fluid dynamics (CFD) studies
indicated that the spark plug side had a combustible mixture with good
homogeneity, whereas the other side that was separated through the wedge on the
piston housed a leaner mixture. Experiments indicated that this physical
stratification allowed a much leaner operation with good combustion phasing
without the dependence of the intake port-generated airflow. The result revealed
higher thermal efficiency, particularly at part loads with lower emissions of
hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx). The
possibility of reducing the output power by leaning the mixture, hence reducing
throttling losses is also demonstrated. The engine was found to be more stable
for a given air-fuel ratio (AFR) as compared to the base flat piston.
Citation: Jose, J., Mittal, M., Ramesh, A., Gnanakotaiah, G. et al., "A Novel Combustion Chamber to Physically Stratify the Charge in a Gasoline Direct Injection Engine," SAE Int. J. Engines 16(3):267-289, 2023, https://doi.org/10.4271/03-16-03-0016. Download Citation
Author(s):
Jubin V. Jose, Mayank Mittal, A. Ramesh, Gutti Gnanakotaiah, Kuduva Shanthu Vishnukumar, Shrinidhi Shridhara
Affiliated:
Indian Institute of Technology Madras, India, TVS Motor Company Limited, India
Pages: 24
ISSN:
1946-3936
e-ISSN:
1946-3944
Related Topics:
Combustion and combustion processes
Combustion chambers
Ignition systems
Computational fluid dynamics
Air / fuel ratio
Nitrogen oxides
Engines
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