This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Heat Transfer and Mixture Vaporization in Intake Port of Spark-Ignition Engine
Annotation ability available
Sector:
Language:
English
Abstract
Time-resolved heat flux and gas temperature measurements in the intake port of a spark ignition engine are presented. Experiments were pursued for motored, propane fired, and liquid fuel operation. Heat transfer coefficients were built from the dry data. Also, heat transfer rates in the port and off the back of the intake valve were integrated over the main flow phases. For a typical low-load propane-fired operating condition, heat transfer in the port caused a mean intake air temperature increase of approximately 10°C. The main different intake flow phases, induction or forward flow, displacement backflow, and valve overlap backflow, contributed approximately 10°C, 3°C, and negative 3°C, respectively. These mixture temperature changes are expected to be also applicable for liquid fuel injected cases.
While the heat flux instrumentation was primarily intended for dry operation of the engine, liquid fuel experiments were also pursued. Liquid fuel vaporization was assessed for isooctane and indolene fuels at thermal steady state and for engine warm-up transients. Spray arrival caused a strong heat flux. For closed valve injection, magnitude of arrival signal was consistent with static spray targeting. Open valve injection deflected the spray upwards and away from the floor of the port. Concurrently, spray impingement onto the valve increased.
For low wall temperatures, vaporization rates inferred from the heat flux measurements compared well to the mixture vaporization potential predicted by analogy to heat transfer. For high wall temperatures, the analogy between heat and mass transfer indicated that all injected fuel could vaporize within one cycle if the fuel film evenly covered the spray targeting area. However, this was neither consistent with the data nor with known engine behavior for injection rate transients, in which a time of several cycles is required for mixture preparation to adjust to changing fueling rates. It is thought that the fuel film does not spread out in a homogenous manner. Rather, discrete fuel droplets or rivulets built up until sufficient surface area allows vaporization at a rate equal to the fuel deposition.
Recommended Content
Authors
Citation
Bauer, W., Balun, P., and Heywood, J., "Heat Transfer and Mixture Vaporization in Intake Port of Spark-Ignition Engine," SAE Technical Paper 972983, 1997, https://doi.org/10.4271/972983.Also In
References
- Borman G. Nishiwaki K. “Internal combustion engine heat transfer,” Prog. Energy Combust. Sci. 13 1 46
- Zapf R. “Contribution to the investigation of heat transfer during charge exchange of a four-stroke Diesel engine,” In German MTZ 30 12 1969
- Shayler P.J. Colechin M. J. F. Scarisbrick A. “Heat transfer measurements in the intake port of a spark ignition engine,” SAE paper 960273
- Shayler P.J. Colechin M. J. F. Scarisbrick A. “Fuel film evaporation and heat transfer in the intake port of an SI engine,” SAE paper 961120
- Shayler P.J. Colechin M. J. F. Scarisbrick A. “Intra-cycle resolution of heat transfer to fuel in the intake port of an SI engine,” SAE paper 961995
- Shayler P.J. Davis M. T. Scarisbrick A. “Intake port fuel transport and emissions: the influence of injector type and fuel composition,” SAE paper 961996
- Shayler P.J. Teo Y. C. Scarisbrick A. “Fuel transport characteristics of spark ignition engines for transient fuel compensation,” SAE paper 950067
- Almkvist G. Erikson S. “An analysis of air to fuel ratio response in a multi point fuel injected engine under transient conditions,” SAE paper 932753
- Brown C. N. Ladommatos N. “A numerical study of fuel evaporation and transportation in the intake port of a port-injected spark-ignition engine,” Proc. Instn. Mech. Engrs 205 161 175
- Martins J. Finlay I. “Fuel Preparation in port-injected engine,” SAE paper 920518
- Bauer W. Heywood J.B. Avanessian O. Chu D. “Flow characteristics in intake port of spark ignition engine investigated by CFD and transient gas temperature measurement,” SAE paper 961997
- Bauer W. Wenisch J. Heywood J. B. “Averaged and time resolved heat transfer of steady and pulsating flow in intake manifold of spark-ignition engine,” Journal of Heat and Fluid Flow
- Pfriem H. “Periodic heat transfer at small pressure fluctuations,” NACA 4 63 67
- Greiner M. Romann P. Steinbrenner U. BOSCH Fuel Injectors - New Developments SAE 870124
- Bauer W. Heywood J.B. “Transfer function of thin film heat flux sensor,” Journal for Experimental Heat Transfer 10 3 1997
- Lienhard J.H. A heat transfer textbook Prentice Hall 1987
- Strikwerda Finite difference schemes and partial differential equations Wadsworth & Brooks/Cole Pacific Groove, California 1989