SUPPLEMENTAL COMPOUNDING CONTROL VALVE FOR ROTARY ENGINE
A rotary engine includes a first transfer duct between a first rotor section and a second rotor section. A second transfer duct is between the second rotor section and the first rotor section. A supplemental compounding control valve selectively controls communication between the first transfer duct and the second transfer duct.
The present disclosure relates to a rotary engine.
Engine technology provides various tradeoffs between power density and fuel consumption. Gas turbine engine technology provides reasonably high power densities, but at relatively small sizes, fuel consumption is relatively high and efficiencies are relatively low. Small diesel piston engines have reasonable fuel consumption but may be relatively heavy with power densities typically below approximately 0.5 hp/lb while equivalently sized four-stroke engines have power densities typically below approximately 0.8 hp/lb. Two-stroke engines have greater power densities than comparably sized four-stroke engines, but have relatively higher fuel consumption.
Various features will become apparent to those skilled in the art from the following detailed description of the disclosed non-limiting embodiment. The drawings that accompany the detailed description can be briefly described as follows:
Referring to
The first rotor 44 and the second rotor 46 have peripheral surfaces which include three circumferentially spaced apexes 44A, 46A respectively. Each apex 44A, 46A include an apex seal 44B, 46B, which are in a sliding sealing engagement with a peripheral surface 48P, 50P of the respective volumes 48, 50. The surfaces of the volumes 48, 50 in planes normal to the axis of rotation A are substantially those of a two-lobed epitrochoid while the surfaces of the rotors 44, 46 in the same planes are substantially those of the three-lobed inner envelope of the two-lobed epitrochoid.
In operation, air enters the engine 20 through the intake port 26 (
The shaft completes one revolution for every cycle, so there are three (3) crank revolutions for each complete rotor revolution. At the top dead center (TDC) position for the first rotor 44, the first rotor volume outlet port 48O and the first rotor volume inlet port 48I are in momentary communication. A supplemental compounding effect is thereby achieved as exhaust gases which are returned from the second rotor volume 50 through the second transfer duct 32 and first rotor volume inlet port 48I flow into the first rotor volume 48 then back into the first transfer duct 30 through the first rotor volume outlet port 48O for communication back into the second rotor volume 50. As the higher pressure exhaust gases are forced into the fixed volume of the first transfer duct 30, the residual compressed air within the first transfer duct 30 is forced into the second rotor volume 50. The residual compressed air from within the first transfer duct 30 is communicated into the second rotor volume 50 which thereby increases the effective compression ratio of the engine 10 through movement of the additional or supplemental air mass flow into the second rotor volume 50 to thereby increase or compound the initial pressure prior to the start of the second rotor 46 compression stroke. With the fixed, geometry defined compression ratio of the second rotor 46, the higher initial pressure for the second rotor 46 stroke results in a higher peak pressure from combustion. This higher pressure, combined with the increased air mass capture, results in increased power output for the engine 10.
Referring to
The supplemental compounding control valve 60 may be utilized to control the supplemental compounding effect at various points in the engine cycle to increase throttling performance, altitude performance and emissions control with a module 70 which executes a supplemental compounding algorithm 72. The functions of the algorithm 72 are, for example, disclosed in terms of a chart (
The module 70 typically includes a processor 70A, a memory 70B, and an interface 70C. The processor 70A may be any type of known microprocessor having desired performance characteristics. The memory 70B may, include various computer readable mediums which store the data and control algorithms described herein. The interface 70C facilitates communication with a flight control computer (FCC) 74, as well as other avionics and systems in the disclosed non-limiting embodiment typical of an unmanned aerial vehicle (UAV).
Referring to
Toward the closed position of the supplemental compounding control valve 60, the peak combustion pressure is minimized to provide for significant engine life. Minimal supplemental compounding occurs as the fixed port geometry between the compressor outlet port 48O and the compressor inlet port 48I alone achieve the minimum inherent supplemental compounding. Toward the open position of the supplemental compounding control valve 60, the effective compression ratio (peak combustion pressure with respect to atmospheric pressure) may be controlled with respect to altitude to generate a desired horsepower. The open position may also be utilized to maximize pressure and facilitate a cold start. The supplemental compounding control valve 60 is then selectively closed as the engine reaches operational temperature to provide a relatively fast engine warm-up. It should be understood that various positions along a continuum between the open and closed positions may be used at various operating conditions to provide desired operational effects.
It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should also be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit herefrom.
Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present disclosure.
The foregoing description is exemplary rather than defined by the limitations within. Various non-limiting embodiments are disclosed herein, however, one of ordinary skill in the art would recognize that various modifications and variations in light of the above teachings will fall within the scope of the appended claims. It is therefore to be understood that within the scope of the appended claims, the disclosure may be practiced other than as specifically described. For that reason the appended claims should be studied to determine true scope and content.
Claims
1. A rotary engine comprising:
- a first rotor section;
- a second rotor section;
- a first transfer duct between said first rotor section and said second rotor section;
- a second transfer duct between said second rotor section and said first rotor section; and
- a supplemental compounding control valve which controls communication between said first transfer duct and said second transfer duct.
2. The rotary engine as recited in claim 1, wherein said first transfer duct communicates compressed air from said first rotor section to said second rotor section.
3. The rotary engine as recited in claim 1, wherein said second transfer duct communicates exhaust gases from said second rotor section to said first rotor section.
4. The rotary engine as recited in claim 3, wherein said supplemental compounding control valve is within said second transfer duct.
5. The rotary engine as recited in claim 1, further comprising a bypass duct between said first transfer duct and said second transfer duct, said supplemental compounding control valve within said second transfer duct.
6. The rotary engine as recited in claim 5, further comprising at least one check valve within said bypass duct.
7. The rotary engine as recited in claim 1, wherein said first rotor section provides a first stage of compression and said second rotor section in communication with said first rotor section through said first transfer duct to provide a second stage of compression, a combustion stage and a first stage of expansion, said second rotor section in communication with said first rotor section through said second transfer duct to provide a second stage of expansion,
8. The rotary engine as recited in claim 1, further comprising a module which controls operation of said supplemental compounding control valve.
9. The rotary engine as recited in claim 8, wherein said module communicates with a flight control computer.
10. A method of controlling a rotary engine comprising:
- communicating compressed air from a first rotor section to a second rotor section through a first transfer duct;
- communicating exhaust gases from the second rotor section to the first rotor section through a second transfer duct; and
- selectively controlling communication between the first transfer duct and the second transfer duct.
11. A method as recited in claim 10, further comprising:
- selectively controlling communication between the first transfer duct and the second transfer duct to control peak combustion pressure.
12. A method as recited in claim 10, further comprising:
- selectively controlling communication between the first transfer duct and the second transfer duct to control peak combustion pressure with respect to atmospheric pressure.
13. A method as recited in claim 10, further comprising:
- selectively controlling communication between the first transfer duct and the second transfer duct to control engine power.
14. A method as recited in claim 10, further comprising:
- selectively controlling communication between the first transfer duct and the second transfer duct to control engine life.
15. A method as recited in claim 10, further comprising:
- selectively controlling communication between the first transfer duct and the second transfer duct to control engine start.
Type: Application
Filed: Oct 8, 2009
Publication Date: Dec 13, 2012
Inventor: Mark David Horn (Granada Hills, CA)
Application Number: 13/497,563
International Classification: F01C 1/04 (20060101);