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Structure of Sprays from Fuel Injectors Part III: The Ford Air-Assisted Fuel Injector
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Abstract
The objective of this study is to characterize the operation of an air-assisted fuel injector. This characterization involves four sets of tests: fuel and air flow calibration; instantaneous measurements of fuel and air solenoid signals, internal pressure in the injector, and poppet lift; photographs of the spray; and droplet sizing. The injector poppet was designed to form a spray of 80° included angle. Nitrogen, instead of air, was used to assist the injection of unleaded gasoline into steady, compressed nitrogen at room temperature. The following conditions were used: nominal fuel flow rates of 10, 20, and 30 mm3/injection; spray chamber pressures of 0.1, 0.169, and 0.445 MPa; and nominal injections per minute (IPM) of 1600 and 3000. Results showed a linear increase in total fuel mass supplied to the injector as fuel solenoid pulse width was increased, except at the highest IPM and chamber pressure when the total fuel mass tended to level off. The mass of fuel injected showed a linear increase with fuel solenoid pulse width while operating at 1600 IPM, but it tended to level off at 3000 IPM. Photographs show that the included angle of the spray decreases with increasing axial distance from the injector, particularly at high chamber pressures. Strong entrainment of liquid droplets toward the spray axis is already visible within the first 5 mm from the nozzle. Asymmetry was also observed. Droplet sizing was completed at 1600 IPM, 0.1 MPa chamber pressure, a nominal fuel flow rate of 20 mm3 per injection, an axial distance 25 mm from the nozzle, and 1 ms after the poppet opened. Sizes of 1.9 microns diameter and larger were measurable using the Malvern Particle Sizer. The maximum diameter was 11 microns and the Sauter Mean Diameter was approximately 2.7 microns. Thus, the spray from this injector is considerably finer than those from similar poppet injectors without air-assist.
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Citation
Emerson, J., Felton, P., and Bracco, F., "Structure of Sprays from Fuel Injectors Part III: The Ford Air-Assisted Fuel Injector," SAE Technical Paper 900478, 1990, https://doi.org/10.4271/900478.Also In
References
- Laforgia, D. Chehroudi, B. Bracco, F.V. “Structure of Sprays From Fuel Injectors - Part II, The Ford DFI-3 Fuel Injector,” Society of Automotive Engineers 1989 International Congress, Paper 890313 February 1989
- Chehroudi, B. Bracco, F.V. “Structure of a Transient Hollow-Cone Spray,” Society of Automotive Engineers 1988 International Congress, Paper 880522 February 1988
- Duret, P. Ecomard, A. Audinet, M. “A New Two-Stroke Engine with Compressed-Air Assisted Fuel Injection for High Efficiency Low Emissions Applications,” SAE Paper 880176 February 1988
- Duret, P. “Device and Method for Injecting Fuel into an Engine, Assisted by Compressed Air or Gas,” United States Patent No. 4,796,594 January 10 1989
- Landfahrer, K. Plohberger, D. Alten, H. Mikulic, L. “Thermodynamic Analysis and Optimization of Two-Stroke Gasoline Engines,” SAE Paper 890415 February 1989
- Schlunke, C.K. Ragg, P.W. Davis, R.M. Lucas, C. “Injection of Fuel to an Engine,” United States Patent No. 4,753,213 June 28 1988
- “The Orbital Combustion Process Engine,” Information Bulletin, Fuels and Lubricants Conference 1989
- Swithenbank, J. Beer, J.M. Taylor, D.S. Abbot, D. McCreath, C.G. ‘A Laser Diagnostic Technique for the Measurement of Droplet and Particle Size Distribution,’ in “Experimental Diagnostics in Gas Phase Combustion Systems,” Progress in Astronautics and Aeronautics 53 421 447 1977
- Felton, P.G. ‘In-stream Measurement of Particle Size Distribution’ “Proceedings of the International Symposium on In-stream Measurements of Particle Solid Properties,” Bergen, Norway 1978
- Emerson, J.R. “Characterization of an Air-Assisted Fuel Injector,” MAE Department, Princeton University Princeton, NJ MSE Thesis No. 1876-T November 1989