Rotary engine
0 United States Patent [1 1 [111 3,877,848  
 Solem 1 Apr. 15, 1975 [54] ROTARY ENGINE 3,825,375 7/1974 Deane 418/61 A [76] Inventor: Edward L. Solem, 321 1 Euclid H i h Bl d Cl l d H i h Primary ExammerWill1am L. Freeh Ohio 4 3 Assistant Examiner-O. T. Sessions 2] F1 d ec 5 1973 Attorney, Agent, or Firm--J. Gibson Semmes [21] Appl. No.: 421,851 [57] ABSTRACT This rotary engine comprises a trilobe rotor mounted [52] US. Cl. 418/61 A, 418/186 for rotation in a trochoidal chamber with 0 osed 51 1m.c|. F01c 1/02 inlet and Outlet ports of unique configuration ig [58] Field of Search 418/61 142 in the end walls of the trochoidal chamber for coac- [56] References Cited tion with complemental propellant gas entrapment channels a m ends of the rotor, per se. A umque accel- UNITED STATES PATENTS erator slider valve located in end walls of the trochoi- 3,193,188 7/1965 Bentele 418/142 131 chamber permits variable timing of engine. 3,519,373 7/1970 Yamamoto 418/61 A 3,762,842 10/1973 George 418/61 A 5 Claims, 8 Drawing Figures HENTEEAFR 1 5i975 SBEET 2 BF 3 son 50 l m i FIG] no 3 l VALVE VL&#39;OO ACTUATION cowsmm 1 FIG 8 O G SOURCE TROCHOiDAL 1 A80 2 ROTOR g CONDENSER 5g CHAMBER |20 VIZO ROTARY ENGINE BACKGROUND OF THE INVENTION This invention relates to engines of the rotary piston type having a triangular-shaped or trilobe rotor travelling in an eccentrically disposed path, wherein a rotor eccentric mounted on a power output shaft permits the rotor to move with its apices constantly in sealing contact with a surrounding trochoidal stator chamber. The basic geometry of such engines is similar to that of the well-known Wankel internal combustion engine, nonetheless, the present is adapted to operate upon non-combustible pressurized gasses, initially generated outside the trochoidal stator chamber. The term gas herein connotes any gasified non-combustible fluid such as, but not limited to, steam.  
 DESCRIPTION OF THE PRIOR ART Pratt discloses a rotary steam engine in U.S. Pat. No. 3,452,643 in which conventional Wankel engine geometry has been altered for steam driven operation through the use of pairs of diametrically opposed inlet and outlet ports located on either side of the minor axis of symmetry of the trochoidal chamber and in the side walls of the chamber. Assuming a constant pressure steam source is used in the Pratt system, the fixed opening of the inlet ports in the side walls of the chamber determines the amount of time that the inlet port is open as each face of the rotor passes. This fixes the period of time in which the steam may expand freely against the rotor, causing it to rotate, before the exhaust port is uncovered. If the inlet port remains uncovered until just before the exhaust port is uncovered, the assumed constant pressure source will act on the rotor continuously during this portion of its movement, presumably providing a high torque performance with low efficiency. If the inlet port remains uncovered for only a short period of time, so that the steam may expand considerably against the rotor before the exhaust port is opened, low torque performance with high efficiency will be obtained. Since the minimum inlet port timing of the Pratt engine is fixed at the side wall of the trochoidal chamber, the torque level and efficiency are accordingly fixed for each operating pressure. Thus, for more torque or power, one must vary the steam pressure. or flux, per se.  
 SUMMARY OF THE INVENTION This invention provides a rotary engine in which output torque and efficiency may be varied for a given gas pressure by varying the size of gas inlet ports. Where constant torque operation is desired or where the engine is to be used with variable pressure steam sources, a fixed size inlet opening may be used to advantage with the unique inlet and outlet port geometries of the invention which coact with flow channels in ends of the rotor.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of engine with one head removed, depicting the rotor with one lobe at the bottom center of the engine stator:  
 FIG. 2 is a perspective view of the rotor, per se;  
  FIG. 3 is a schematic view of the rotor in its stator chamber, depicting the rotor displaced by ninety degrees from the position of FIG. 1;  
  FIG. 4 is a schematic view of the rotor in its stator chamber, the rotor being displaced by ninety degrees from the position of FIG. 3;  
  FIG. 5 is a perspective view of inlet valve slider plate and actuator rod;  
  FIG. 6 is a perspective view of the inlet valve cover plate;  
  FIG. 7 is a vertical section of the inlet valve slider plate and inlet valve cover plate.  
  FIG. 8 is a schematic drawing of the rotary engine and compressed gas source.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS There follows a detailed description of the invention, reference being had to the drawings in which like reference numerals depict like elements of structure in each of the several FIGURES.  
  FIG. 1 shows the block of the engine 100 which defines the trochoidal chamber at side wall 112 and may include cooling chambers or water jackets 114.  
  Trilobe rotor 200 includes a ring gear 210 which is external of the eccentric bearing bore 220. Output shaft 300 includes a fixed eccentric or cam 320, eccentric 320 of output shaft 300 bearing in bore 220 of the rotor. Fixed reaction gear 310 is concentric to the output shaft 300 and is attached to the end wall (not shown). Reference FIG. 2 apices seals 230, connecting seals 340 and central seal 350 will seal the respective gas expansion chambers of the rotor 200 from each other and from the central portion of said rotor. While not shown, the respective seals 340 and 350 are in sealing contact on at least the three immediately adjacent joints 360 of each rotor chamber. Three straight radial seals may be set between the two; for the purpose. Whereas one face only of the rotor is shown, in FIGS. 1 through 4, both faces define like expansion chambers and all sealing means are disposed in coactive sealing relationship to contacting portions of the interior of the engine head, not shown.  
  Rotor 200 includes on each of its end faces three cutaway gas propellant flow channels 250 which in operation coact with the inlet and outlet ports of the head in a manner to be described. Assuming counter clockwise rotation of the rotor leading wall 252 of each flow channel 250 extends from the outer periphery 240 of the rotor 200, inward toward the rotor center, to a point 254 which is spaced in close proximity to bore 220. This spacing depends upon maximum inlet port size required for a particular engine operating characteristic and on such thickness of material that must remain between gas flow channels 250 and bore 220, to permit installation of respective seals 340. Trailing wall 256 of each flow channel 250 is curved from point 254 to a point 258 located on the periphery of the rotor such that 258 passes the counter clockwise edge of 90 degrees after 252 passes the clockwise edge of 160. The precise shape of the trailing walls and the radial depth of the leading walls may be varied, it will be appreciated, as required for a particular application; however, the geometry shown provides for a gradual closing of each stator inlet port as the rotor turns.  
  FIG. 2 being a perspective view of the rotor, indicates most clearly the preferred geometry of rotor channels 250. There are three such channels on each side of the rotor in the preferred embodiment, to coact with fixed inlet and exhaust ports located in both end walls of the stator chamber. Nonetheless, it will be appreciated that said inlets could be disposed on one end of the stator chamber and outlets on the other or both on one end only, with flow channels disposed in the rotor as required, without departing from the spirit of this invention. While each flow channel 250 is shown cut into the end surface of the rotor to uniform depth on all sides this is a design variable, viz; the channel may be cut shallower at the leading Wall 252 than at the terminus 258 of the trailing wall.  
  Withreference to the rotor 200 in the position shown in FIG. 1, at apex A, the disposition of the leading edge 152 of the stator inlet port to be described is clearly defined as immediately adjacent and parallel to the leading wall 252 of flow channel 250. Trailing edge 154 of the stator is parallel to leading edge 152 and spaced therefrom as shown, the spacing being a matter of design choice, depending upon the inlet port size desired. Diametrically opposite stator inlet port is similarly located. Both inlet ports may be partially or fully opened, using a slider valve of the type shown in FIG. 5. Stator exhaust ports 180 are set in end walls of the stator chamber and lead through channels 182 to exhaust head connections I84.  
  Schematic drawing FIG. 3 shows rotor 200 in the stator chamber, defined by trochoidal side wall 112. The rotor is depicted as having rotated 90 relative to the chamber, from the position of FIG. 1. See the relationshipof apices A, B and C in respective FIGS. 1, 3 and 4. Leading edge 152 of exhaust port 150 is parallel and overlying the leading edges 252 of rotor flow channels 250. Essentially, circumferential segments 154 and 154 of the exhaust ports run perpendicular to edge 152 in a manner paralleling the counterparts of inlet ports 1 60.  
  In FIG. 4, the schematic of rotor 200 is again shown in thestator chamber, defined by side wall 112. The rotor has again rotated another 90 from the position in FIG. 3. The trailing edge 156 of exhaust port 150 in stator head is immediately adjacent and parallel to the moving trailing edge 256 of flow channel 250. The inboard edge 156 of the exhaust port is faced in between segment 154&#39; and trailing edge 156, so as to permit adequate clearance with bore 220. The diametrically opposed exhaust port is similarly located relative to the bore 220.  
  FIGS. 5 to 7 are views of inlet port slider valve 400 and a combination valve body and inlet manifold adaptor 500 of the invention offering a variable inlet opening. The valve 400 may be parallel to the inlet port 160. A combination valve body and inlet manifold adaptor 500 is removably located on the end walls of the stator. When slider valve 400 is fully inserted into the valve body and inlet manifold 500, no gas canenter the engine. As the adjustable slider valve 400 is withdrawn from the valve body and inlet manifold body 500, an opening to the engine, comprised of face 402 and edges 502, 504 and 504, is created. The size of this variable inlet opening is determined by the position of the slider valve 400. F ace 404 of slide valve 400 is flush with the interior side of the stator end wall. The opening formed by edges 502, 506, 508 and 508 is connected to the compressed gas source.  
  In the schematic of FIG. 8 there is depicted a steam driven rotary engine embodying the invention. Pairs of inlet and exhaust ports are located in each head 120 at either end of the trochoidal chamber 110. The individual inlet slider valves are actuated by a suitable acceler ator mechanism 400 such .as could be devised by one of ordinary skill in the art. Steam or other gas from an essentially constant pressure source 420 is directed through the inlet ports into contact with the channels of the rotor. As slider valve plates may be extended outwardly, the stator inlet ports remain open for a progressively greater length of time, relative to the movement of the rotor, yielding high torque, low efficiency performance. As one establishes a smaller inlet opening, the inlet ports are shut more quickly by the coac- I tion with the rotor flow channels, yielding low torque, high efficiency performance. In the former situation, the steam has little chance to expand and use its energy, to move the rotor; however, in the latter situation, a relatively long expansion cycle is obtained after the inlet opening is closed which permits optimum use of the energy of the steam. Steam exhausts through the stator ports to condenser 430 from which condensate is returned to steam source 420. I  
  The invention in its essential concept is defined in the following claims: I  
 I claim: 1. A rotary engine comprising a. a stator block defining a trochoidal chamber, said stator block having closed ends, said ends defining at least one propellant linear slot gas inlet of adjustable size and at least one corresponding gas outlet,  
 disposed in operative relation to the said linear slot gas inlet; b. a trilobe rotor sealed within the trochoidalchamber between the ends thereof, said rotor containing of the channel being substantially parallel to the radius of the rotor, per se, the said channel being dis-. posed in fluid flow relation to the respective gas inlet and gas outlet;  
 c. a drive shaft having a cam engageable with the tri-. lobe rotor, the shaft bearing in ends of the trochoi-r dal chamber; and  
 d. a source of propellant gas connected to the propellant gas inlet wherein by rotor operation, the gas channel of the rotor and gas inlets of the stator respectively define opposed gas expansion and contraction confines, whereupon by movement of the rotor propellant gas is admitted through said gas inlet and said gas channel and a gradual expansion of the propellant occurs and is applied to the drive shaft cam by movement of the rotor about the trochoidal chamber.  
 2. The engine of claim 1, wherein the respective gas inlets of the stator are substantially rectangular, the  
 leading edge of each inlet being aligned with the radius of the leading edge of the rotor gas channel in its path about the trochoidal chamber of the stator.  
  3. The engine of claim 1, wherein the gas inlet of the stator is substantially rectangular, the leading edge of each inlet being aligned with the radius of the leading edge of the rotor in its path about the trochoidal chamber.  
  4. The engine of claim 3 wherein the respective channels of the trilobe rotor are three in number on at least channels of the rotor are three in number on each side of the rotor and wherein the respective stator outlet and inlet chambers are two in number on each side of the engine.