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A Visualization Study of Liquid Fuel Distribution and Combustion Inside a Port-Injected Gasoline Engine Under Different Start Conditions
Technical Paper
2000-01-0242
ISSN: 0148-7191, e-ISSN: 2688-3627
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Event:
SAE 2000 World Congress
Language:
English
Abstract
High-speed video of combustion processes and cylinder pressure traces were obtained from a single-cylinder optical-accessible engine with a production four-valve cylinder head to study the mixture formation and flame propagation characteristics at near-stoichiometric start condition. Laser-sheet Mie-scattering images were collected for liquid droplet distributions inside the cylinder to correlate the mixture formation process with the combustion results. A dual-stream (DS) injector and a quad-stream (QS) injector were used to study the spray dispersion effect on engine starting, under different injection timings, throttle valve positions, engine speeds, and intake temperatures.
It was found that most of the fuel under open-valve injection (OVI) conditions entered the cylinder as droplet mist. A significant part of the fuel droplets hit the far end of the cylinder wall at the exhaust-valve side. Some of the droplets were found to travel toward the squish area at the short side of the intake valves. Images taken just before spark timing showed that significant fraction of the fuel was still in the liquid phase. In contrast, Mie-scattering images did not show significant fuel droplets entering the imaging plane under close-valve injection (CVI) conditions.
The combustion video showed that combustion during the early cycles of cold start could be categorized into three phases. The first phase was at those early cycles when most of the injected fuel ended up as liquid film on the chamber walls, with insufficiently vaporized fuel in the mixture to sustain combustion. The second phase started when visible weak flame fronts appeared due to improvement in liquid vaporization process. Diffusion-controlled pockets became obvious at this phase and the in-cylinder pressure increase was also significant. The third phase started when the heat of combustion evaporated most of the liquid fuel and produced an overall-rich mixture that combusted at a higher rate and produced a higher cylinder pressure.
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Citation
Zughyer, J., Zhao, F., Lai, M., and Lee, K., "A Visualization Study of Liquid Fuel Distribution and Combustion Inside a Port-Injected Gasoline Engine Under Different Start Conditions," SAE Technical Paper 2000-01-0242, 2000, https://doi.org/10.4271/2000-01-0242.Also In
Combustion, Flow Diagnostics, and In-Cylinder Velocity Measurement
Number: SP-1529; Published: 2000-03-06
Number: SP-1529; Published: 2000-03-06
References
- Shine, Y. Cheng, W. K. Heywood, J. B. “Liquid Gasoline Behavior in the Engine Cylinder of a SI Engine,” SAE Paper, No. 941872 1994
- Meyer, R. Heywood, J. B. “Liquid Fuel Transport Mechanisms into the Cylinder of a Firing Port-Injected SI Engine During Start Up,” SAE Paper, No. 970865 1997
- Nogi, T. Ohyama, Y. Yamauchi, T. Kuroiwa, H. “Mixture Formation of Fuel Injection Systems in gasoline Engine,” SAE Paper, No. 880558 1988
- Nogi, T. Ohyama, Y. Yamauchi, T. “Effects of Mixture Formation of Fuel Injection Systems in Gasoline Engine,” SAE Paper, No. 891961 1989
- Witze, P. O. Green, R. M. “LIF Visualization of Liquid Fuel in the Cylinder of a Spark Ignition Engine” Proceedings of the Eighth International Symposium on Applications of Laser Techniques to Fluid Mechanics 1996
- Witze, P. O. Green, R. M. “LIF and Flame-Emission Imaging of Liquid Fuel Films and Pool Fires in an SI Engine During a Simulated Cold Start,” SAE Paper, No. 970866 1997
- Campbell, S. Clasen, E. Chang, C. Rhee, K. T. “Flames and Liquid Fuel in an SI Engine Cylinder During Cold Start,” SAE Paper, No. 961153 1996
- Zhao, F. Q. Lai, M. C. Harrington, D. L. “The Spray Characteristics of Automotive Port Fuel Injection - A Critical Review,” SAE Paper, No. 950506 1995
- Zhao, F. Q. Yoo, J. H. Lai, M. C. “Spray Targeting Inside a Production-Type Intake Port of a 4-Valve Gasoline Engine,” SAE Paper, No. 960115 1996