Transient Fuel Spray Structure for Simulated Injection Strategies in Direct Injection, Spark Ignition Engines

2001 ◽  
Author(s):  
P. A. Hutchison ◽  
R. B. Wicker
Keyword(s):  
Flow Visualization ◽  
Cross Section ◽  
Direct Injection ◽  
Fuel Spray ◽  
Spark Ignition Engines ◽  
Rail Pressure ◽  
Fuel Injectors ◽  
Spray Structure ◽  
Image Velocimetry ◽  
Direct Injection Spark Ignition

Abstract For two production DISI fuel injectors, flow visualization and particle image velocimetry (PIV) were utilized to illustrate the effect of fuel rail pressure and in-cylinder density (using in-cylinder pressure) on instantaneous fuel spray structure. Studies were performed within a non-motored research cylinder for two fuel rail pressures (3 MPa and 5 MPa) and two in-cylinder pressures (2 atm and 6 atm). Instantaneous flow visualization demonstrated the effects of changes in fuel rail pressure and in-cylinder density on transient spray structure. Increased fuel rail pressure resulted in increased narrowing of the spray cross-section and increased spray penetration distance. Increased in-cylinder density produced sprays with increased narrowing of the spray cross-section and shorter penetration distances. Spray velocities were shown to increase with increased fuel rail pressure and decrease with increased in-cylinder density.

Simultaneous High-Speed Imaging of Fuel Spray, Combustion Luminosity, and Soot Luminosity in a Spray-Guided Direct Injection Engine With Different Multi-Hole Fuel Injectors

2013 ◽  
Author(s):  
Ming Zhang ◽  
Michael C. Drake ◽  
Kevin Peterson
Keyword(s):  
High Speed ◽  
Soot Formation ◽  
Direct Injection ◽  
Fuel Spray ◽  
Exhaust Emission ◽  
Injection Timing ◽  
Gaseous Emissions ◽  
High Speed Imaging ◽  
Fuel Injectors ◽  
Spray Structure

Eight different multi-hole fuel injectors with nominally the same exterior geometry (8-hole, 60 degree circular symmetric spray pattern) but different levels of development (Generation I and Generation II), length-to-diameter (L/D) ratios (1.4 to 2.4), and manufacturing processes (EDM vs. laser drilled) are compared in a spray-guided, spark-ignition direct injection (SG-SIDI) single-cylinder optical engine. In-cylinder pressure measurements and exhaust emission measurements quantified effects of different injectors on combustion and emissions. Crank-angle-resolved white-light spray imaging and simultaneous flame and soot visualization quantified variations in spray structure, combustion propagation, and soot formation and oxidation. At a single operating condition (2000rpm, 95kPa inlet pressure, 90°C engine temperature, end of injection timing (EOI) @ 36 BTDC, spark advance (SA) @ 36 BTDC, 8.1mg/injection), all eight injectors have nearly the same IMEP (about 270kPa) and engine-out gaseous emissions. Experiments show that laser drilled injectors with lower L/D ratios (L/D = 1.4–2.0) have a totally collapsed fuel spray structure, a more penetrating liquid spray with severe fuel impingement on the piston, and rapidly-forming soot deposits on the piston. The collapsed, more compact fuel spray vaporized more slowly and the resulting rich zones led to strong soot luminosity. In contrast, the laser drilled injector with the highest L/D ratio (2.4) and the two EDM injectors (Generation I and Generation II with L/D = 2.0) show 8 distinct spray plumes, less fuel impingement, and much less soot emission intensity. Image analysis tools developed in Matlab were used to characterize the flame propagation and soot formation processes.

Simulation of Coarse Droplet and Liquid Column Formed around Nozzle Outlets Due to Valve Wobble of a Gasoline Direct Injection Injector

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Eiji Ishii ◽  
Yoshihito Yasukawa ◽  
Kazuki Yoshimura ◽  
Kiyotaka Ogura
Keyword(s):  
Surface Tension ◽  
Particulate Matter ◽  
Direct Injection ◽  
Gasoline Direct Injection ◽  
Fuel Spray ◽  
Direct Injection Engines ◽  
Fuel Injectors ◽  
Multiple Injections ◽  
Fuel Mixtures ◽  
Opening And Closing

The generation of particulate matter (PM) is one problem with gasoline direct-injection engines. PM is generated in high-density regions of fuel. Uniform air/fuel mixtures and short fuel-spray durations with multiple injections are effective in enabling the valves of fuel injectors not to wobble and dribble. We previously studied what effects the opening and closing of valves had on fuel spray behavior and found that valve motions in the opening and closing directions affected spray behavior and generated coarse droplets during the end-of-injection. We focused on the effects of valve wobbling on fuel spray behavior in this study, especially on the behavior during the end-of-injection. The effects of wobbling on fuel spray with full valve strokes were first studied, and we found that simulated spray behaviors agreed well with the measured ones. We also studied the effects on fuel dribble during end-of-injection. When a valve wobbled from left to right, the fuel dribble decreased in comparison with a case without wobbling. When a valve wobbled from the front to the rear, however, fuel dribble increased. Surface tension significantly affected fuel dribble, especially in forming low-speed liquid columns and coarse droplets. Fuel dribble was simulated while changing the wetting angle on walls from 60 to 5 deg. We found that the appearance of coarse droplets in sprays decreased during the end-of-injection by changing the wetting angles from 60 to 5 deg.

AN APPROACH TO MODELING FLASH-BOILING FUEL SPRAYS FOR DIRECT-INJECTION SPARK-IGNITION ENGINES

2016 ◽  
Vol 26 (12) ◽  
pp. 1197-1239 ◽  
Author(s):  
Christopher Price ◽  
Arash Hamzehloo ◽  
Pavlos Aleiferis ◽  
David Richardson
Keyword(s):  
Direct Injection ◽  
Spark Ignition ◽  
Spark Ignition Engines ◽  
Fuel Sprays ◽  
Flash Boiling ◽  
Direct Injection Spark Ignition

A phenomenological mixture homogenization model for spark-ignition direct-injection engines

2017 ◽  
Vol 19 (2) ◽  
pp. 168-178 ◽  
Author(s):  
Stefan Frommater ◽  
Jens Neumann ◽  
Christian Hasse
Keyword(s):  
Equivalence Ratio ◽  
Direct Injection ◽  
Three Dimensional ◽  
Control Unit ◽  
Spark Ignition ◽  
Engine Control Unit ◽  
Operating Conditions ◽  
Spark Ignition Engines ◽  
Ratio Distribution ◽  
Direct Injection Spark Ignition

In modern turbocharged direct-injection, spark-ignition engines, proper calibration of the engine control unit is essential to handle the increasing variability of actuators. The physically based simulation of engine processes such as mixture homogenization enables a model-based calibration of the engine control unit to identify an ideal set of actuator settings, for example, for efficient combustion with reduced exhaust emissions. In this work, a zero-dimensional phenomenological model for direct-injection, spark-ignition engines is presented that allows the equivalence ratio distribution function in the combustion chamber to be calculated and its development is tracked over time. The model considers the engine geometry, mixing time, charge motion and spray–charge interaction. Accompanying three-dimensional computational fluid dynamics, simulations are performed to obtain information on homogeneity at different operating conditions and to calibrate the model. The calibrated model matches the three-dimensional computational fluid dynamics reference both for the temporal homogeneity development and for the equivalence ratio distribution at the ignition time, respectively. When the model is validated outside the calibrated operating conditions, this shows satisfying results in terms of mixture homogeneity at the time of ignition. Additionally, only a slight modification of the calibration is shown to be required when transferring the model to a comparable engine. While the model is primarily aimed at target applications such as a direct-injection, spark-ignition soot emission model, its application to other issues, such as gaseous exhaust emissions, engine knock or cyclic fluctuations, is conceivable due to its general structure. The fast calculation enables mixture inhomogeneities to be estimated during driving cycle simulations.

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