This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Spray Behaviors and Gasoline Direct Injection Engine Performance Using Ultrahigh Injection Pressures up to 1500 Bar
Journal Article
03-15-01-0007
ISSN: 1946-3936, e-ISSN: 1946-3944
Sector:
Topic:
Citation:
Yamaguchi, A., Koopmans, L., Helmantel, A., Dillner, J. et al., "Spray Behaviors and Gasoline Direct Injection Engine Performance Using Ultrahigh Injection Pressures up to 1500 Bar," SAE Int. J. Engines 15(2):167-183, 2022, https://doi.org/10.4271/03-15-01-0007.
Language:
English
Abstract:
High fuel injection pressure systems for Gasoline Direct Injection (GDI) engines
have become widely used in passenger car engines to reduce emissions of
particulates and pollutant gases. Current commercial systems operate at
pressures of up to 450 bar, but several studies have examined the use of
injection pressures above 600 bar, and some have even used pressures around 1500
bar. These works revealed that high injection pressures have numerous benefits
including reduced particulate emissions, but there is still a need for more data
on the possible benefits of injection pressures above 1000 bar. This article
presents spray and engine data from a comprehensive study using several
measurement techniques in a spray chamber and optical and metal engines.
Shadowgraph imaging and Phase Doppler Interferometry (PDI) were used in a
constant volume chamber to interpret spray behavior. Particle Image Velocimetry
(PIV) was used to capture near-nozzle air entrainment. Optical engine
experiments were performed to visualize the spray’s position relative to the
piston at different start of injection (SOI) timings. A single-cylinder GDI
engine was used to investigate the effects of injection pressure on emissions
and combustion characteristics. The spray tests showed that high-pressure sprays
tend to exhibit better atomization and create more air entrainment, accelerating
evaporation and mixing. However, high pressures also cause high spray tip
penetration due to the high spray velocity, potentially causing wall film
formation. At commonly used SOI timings, the benefits of high-pressure injection
are relatively insignificant. The improvements in combustion stability and
emissions of hydrocarbon (HC) and particulates are greater when the SOI timing
is advanced (≈340°bTDC) or retarded (later than 180°bTDC). Wall film occurs at
advanced SOI timing for all injection pressures, but high injection pressures
significantly reduce particle number (PN) emissions by affecting wall film
formation. At late SOI timings, high injection pressures yield acceptable
combustion stability and emissions because they shorten the injection and
promote mixing. These results suggest that high-pressure sprays allow HC and PN
emissions to be greatly reduced and increase flexibility with respect to
injection timing without sacrificing engine performance or increasing other
emissions. Fuel consumption is also improved, but the effect is more significant
when the injection pressure is 1000 bar.