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Liquid Fuel Vaporization Process Built Inside Wankel Rotary Engines
Technical Paper
2012-36-0124
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
The purpose of this paper is to describe a novel liquid fuel
conditioning process that is incorporated within a Wankel type
rotary engine. The process takes place inside three small
vaporization chambers attached to the engine rotor. After an
injected liquid fuel has evaporated and superheated inside a
vaporization chamber, it is transferred via a transfer port into a
moving chamber near the middle of a compression phase to form a
stratified mixture with a prevailing fresh air charge. Combustion
is triggered by a spark. Near the end of an expansion phase hot
combustion products enter the vaporization chamber via an
entrapment port. Thereafter, those products are entrapped inside
the vaporization chamber during about 180° of rotor rotation.
Unlike spark ignition, compression ignition or homogeneous
charge compression ignition engines, here the liquid fuel is
injected into the vaporization chamber during the exhaust phase of
a preceding cycle. Fuel droplets absorb heat from the hot entrapped
combustion products and vaporization chamber walls, where they
evaporate and reach a superheated gaseous state. Calculations
predict that the residence time available inside a typical
vaporization chamber of an engine running at 7,000 RPM is
sufficient to evaporate and superheat diesel fuel droplets of 100
micron SMD.
It is anticipated that this novel concept could substantially
reduce the untreated emission levels of nitrogen oxides, carbon
monoxide, particulate matter and unburned hydrocarbons when
compared to contemporary Wankel type rotary engines. This
projection implies that less costly and simpler after-treatment
devices will suffice to comply with emission standard
regulations.
An improvement in engine fuel economy is expected because: (1)
efficient and stable stratified combustion process, (2) unthrottled
operation and (3) faster heat release rate than that corresponding
to present-day Wankel type rotary engines.
The moving chamber exhibits an over-elongated contour that
develops while it is rotating around top dead center whose geometry
allows running on much lower octane rated gasoline than a
comparable piston engine. Also, because the fuel is vaporized,
diesel knocking is prevented and therefore the fuel does not need
to be rated for high-octane or cetane numbers. This feature allows
the engine to efficiently employ gasoline or diesel fuels without
additives or blends. Additionally, the system is expected to
effectively utilize low-cost petroleum-derived fuel, biodiesel and
vegetable oil.
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Authors
Topic
Citation
Trucco, H., "Liquid Fuel Vaporization Process Built Inside Wankel Rotary Engines," SAE Technical Paper 2012-36-0124, 2012, https://doi.org/10.4271/2012-36-0124.Also In
References
- Wikipidia “Wankel Engine” Http://En.Wikipedia.Org/Wiki/Wankel_Engine July 1 2012
- Trucco, Horacio A. “Wankel Type Rotary Engine Incorporating An Internal Liquid Fuel Conditioning Process” US Patent Application Number 13402810 February 22 2012
- Mazda “What Is The Rotaty Engine?” Http://Www.Mazda.Com/Mazdaspirit/Rotary/About/ July 1 2012
- Castrogiovanni, A. “A Parametric Study of Fuel Spray Evaporation” ACENT Laboratories Technical Note TN-12- 100 January 2012
- Taşkiran, Özgür Oğuz Ergeneman, Metin “Experimental Study on Diesel Spray Characteristics and Autoignition Process” Journal of Combustion 2011 http://www.hindawi.com/journals/jc/2011/528126/ July 1 2012
- McAllister, Sara Chen, Jyh-Yuan Fernandez-Pello, A. Carlos “Fundamentals of Combustion Processes” Springer 2011