Internal-combustion engines – Rotary – With transfer means intermediate single compression volume...
Reexamination Certificate
2000-05-04
2001-08-14
Nguyen, Hoang (Department: 3748)
Internal-combustion engines
Rotary
With transfer means intermediate single compression volume...
C123S213000, C123S215000, C123S234000
Reexamination Certificate
active
06273055
ABSTRACT:
TECHNICAL FIELD
This invention relates to rotary combustion engines.
BACKGROUND
Over the past several decades, considerable effort has been expended to find successful alternatives to the reciprocating internal combustion engine which improve upon the features and advantages of that engine. Alternative external and internal combustion engines, e.g., the Wankel, Tri-Dyne and Stirling engines, have been developed as a part of this effort. However, so far as is known, none of the rotary engines developed heretofore have provided an efficient power source while also successfully addressing both the reduction or elimination of the accompanying vibration and noise associated with traditional reciprocating internal combustion engines and the thermodynamic problems historically associated with continuous combustion.
Thus, a need continues to exist for a continuous combustion engine which provides efficient power in a substantially quiescent manner using economically feasible materials and construction capable of withstanding the thermal conditions brought to bear during engine operation.
SUMMARY OF THE INVENTION
The present invention is deemed to satisfy this need in a highly effective and efficient manner. In one embodiment of this invention, a combustion engine is provided. The engine is comprised of at least one compression stage, at least one combustion unit, and at least one expansion stage. The compression stage is comprised of a first housing portion defining two or more overlapping cylindrical bores and two or more cylindrical compression rotors which are disposed within the first housing portion and concentrically aligned within the bores respectively so that the compression rotors are in substantially sealing relation with one another at their respective pitch diameters. The compression stage is configured to (1) receive a fluid volume through a fluid inlet in the first housing portion, (2) compress the fluid volume, and (3) convey at least a portion of the compressed fluid volume to the combustion unit. The expansion stage is comprised of a second housing portion defining two or more overlapping cylindrical bores and two or more cylindrical expansion rotors which are disposed within the second housing portion and concentrically aligned within the bores respectively so that the expansion rotors are in substantially sealing relation with one another at their respective pitch diameters. The expansion stage is configured to receive an expanding combustion volume from the combustion unit and to convey the combustion volume out of the second housing portion through an exhaust port, the combustion volume imparting a force to the expansion rotors, the force urging the expansion rotors to rotate. The second housing portion and associated expansion rotors are preferably configured to be cooled by a circulating fluid, e.g., air.
Each of the compression and expansion rotors in the engine is comprised of at least two male lobes diametrically opposed from one another, each lobe extending the entire axial length of the rotor and extending radially from the rotor axis of rotation beyond the rotor's pitch diameter so as to be in close proximity to an adjacent surface of the respective cylindrical bore. Each of the rotors of the engine further defines at least two female grooves extending inwardly toward the rotational axis from their respective rotor pitch diameter, the grooves of each rotor being diametrically opposed from one another and configured for receiving a respective lobe on the adjacent rotor. Preferably, each of the grooves is circumferentially disposed in the range of about 0° (i.e., a substantially contiguous offset) to about 90°, and more preferably about 45° to about 90°, most preferably about 90°, from an adjacent lobe. In this way, as a corresponding group of rotors rotates, the outer surfaces of the rotors at the respective pitch diameters are maintained in substantially sealing relation, the seal being substantially maintained even while the lobe of one of the rotors engages and then disengages a corresponding groove on another rotor in the group of rotors. The outermost surface of each lobe is also in sufficient proximity to the surface of the corresponding housing bore to create a seal there between. In this way, the rotors and the housing bores define a volume which is efficiently displaced with every rotation.
In a preferred embodiment, a portion of the compressed fluid volume from the compression stage is circulated through at least a portion of the second housing portion, and more preferably also through at least one of the corresponding expansion rotors. Also, it will be understood that the fluid volume displaced by the engine of this invention may be circulated through the engine via an open cycle (e.g., air in and exhaust out) or a closed cycle (e.g., recycled inert fluid, e.g., helium), as desired.
In a particularly preferred embodiment, at least one of the stages (compression and expansion) is itself multi-staged. That is, at least one of the stages is comprised of a series of two or more sub-stages, the sub-stages in each series having progressively smaller (on the compression side) or larger (on the expansion side) clearance volumes defined by the housing bores and the corresponding compression or expansion rotors therein, as applicable. In this way, the fluid volume to be compressed in the compression stage may be most efficiently compressed and the energy within the combustion volume may be efficiently converted into mechanical energy.
These and other embodiments and features of the invention will become still further apparent from the ensuing description, appended claims and accompanying drawings.
REFERENCES:
patent: 3574491 (1971-04-01), Martin
patent: 3699930 (1972-10-01), Bunce
patent: 3782340 (1974-01-01), Nam
patent: 3993029 (1976-11-01), Eiermann et al.
patent: 4265606 (1981-05-01), Lehnus
patent: 4405286 (1983-09-01), Studer
patent: 4747762 (1988-05-01), Fairbairn
patent: 4893996 (1990-01-01), Loran et al.
patent: 4912924 (1990-04-01), Stockwell
patent: 5222992 (1993-06-01), Fleischmann
patent: 5682793 (1997-11-01), Liao
Nguyen Hoang
Sieberth & Patty L.L.C.
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