Patent Publication Number: US-8117826-B1

Title: External combustion engine with rotary piston controlled valve

Description:
TECHNICAL FIELD 
     The invention relates generally to mechanical engines and, more particularly, to combustion engines. 
     BACKGROUND 
     Modern society bases most of its transportation infrastructure on the internal combustion engine. From automobiles to airplanes, the internal combustion engine drives much of commerce. Generally, the internal combustion engine uses the combustion of a fuel source with an oxidizer to generate gases under high pressure. The design of most internal combustion engines direct these gases against a mechanical component. This causes the mechanical component to move, converting the combustion process into mechanical energy harnessed to perform work. These engines can vary greatly in size and be used in numerous applications. 
     A cycle consisting of four events generally describes the basic operation of an internal combustion engine. These events are intake, compression, power (ignition), and exhaust. During intake, a fuel source, such as gasoline, and an oxidizer, such as air, are drawn into, or pumped into, a combustion chamber through valves operated by a camshaft. The two combustible ingredients, the fuel source and the oxidizer, mix within the combustion chamber. Next, compression occurs. During compression, the combustible ingredients are placed under pressure. Usually a piston, the maximum range of motion of which is controlled by a crankshaft to which the piston is attached, moves into the combustion chamber, decreasing the volume of the combustion chamber and placing the fuel source and oxidizer under great pressure. At the point of greatest compression, an igniter, such as a spark from a spark plug, ignites the combustible ingredients causing the rapid conversion of the combustible ingredients into a rapidly expanding gas. This rapidly expanding gas generates a force against the piston causing the piston to move in a manner that increases the volume of the combustion chamber. It is this motion that generates mechanical energy harnessed through the crankshaft and other components. Finally, the piston reaches the maximum range of expansion as determined by the crankshaft. As the crankshaft turns it pushes the piston back into the combustion chamber where the combustion gases exhaust through a valve opened through operation of the camshaft. In different variations of the internal combustion engine, the events can be combined in certain specific ways to create engines that better fit certain applications. 
     As ubiquitous as the internal combustion engine is, it also suffers from some serious drawbacks. For example, because the internal combustion engine must operate at high pressures, the components must be extremely strong, necessitating heavy overbuilt components, or lightweight expensive components. Heavy components decrease the efficiency and use of the engine, and lightweight components drive up the cost of the engine limiting, the number of applications to which it can reasonably be applied. Thus, there is a need for a combustion engine that does not need to operate at such high pressures. 
     The high pressures can also necessitate that the engines be finely tuned, and limited to one particular type of fuel so that a specific pressure, fuel, and oxidizer must be used at all times. This limits the applications to which any individual engine can be placed. Furthermore, it increases the dependence of the those using the engine on a particular fuel source. Thus, there is a need for combustion engines, where a user can easily convert any individual engine to run on multiple fuel sources depending on what is available, and the type of work that is to be performed. 
     Finally, regardless of the type of components, internal combustion engines must operate a crankshaft and camshaft assembly to successfully complete the engine cycle that generates power. Operation of these components is necessary to continue the operation of the engine; yet, with each cycle, power that could otherwise be directed to the purpose of the engine is leached by these components. This decreases the engine&#39;s efficiency and drives up the cost of operation through increased fuel costs. Thus, there is a need for a combustion engine that decreases efficiency losses due to components such as the crankshaft and camshaft. 
     SUMMARY 
     The present invention, accordingly, provides an external combustion engine comprising a first engine housing defining a first engine chamber, wherein the first engine chamber comprises a space for containing and directing expansive gas generated by combustion of a fuel. The invention includes a combustion chamber coupled to the first engine housing such that expanding gas produced by combustion of a fuel passes from the combustion chamber into the first engine housing through a combustion gas inlet. The engine also includes a driveshaft positioned within the first engine housing such that the driveshaft extends from a center of the first engine housing and passes through a wall of the first engine housing such that devices may couple to the external combustion engine by means of the driveshaft. The driveshaft rotates about a driveshaft axis passing lengthwise through a center of the driveshaft. The engine includes a first rotatable piston positioned within the first engine housing, coupled to the driveshaft, and configured to rotate about the driveshaft axis when expansive gas resulting from combustion of a fuel contacts the first rotatable piston. A first backstop valve couples to the first engine housing such that the first backstop valve directs expansive gas resulting from combustion of a fuel toward the first rotatable piston. The first engine housing further defines a first exhaust outlet configured to exhaust used expansive gas resulting from combustion of a fuel. Finally, the engine includes ignition and timing controls coupled to the first engine housing and configured to combust a fuel. 
     Yet another embodiment of the invention provides an external combustion engine comprising a first engine housing defining a first engine chamber, wherein the first engine chamber comprises a space for containing and directing expansive gas generated by combustion of a fuel. The engine also includes at least one combustion chamber coupled to the first engine housing such that expanding gas produced by combustion of a fuel passes from the combustion chamber into the first engine housing through a combustion gas inlet. The engine includes a driveshaft positioned within the first engine housing such that the driveshaft extends from a center of the first engine housing and passes through a wall of the first engine housing such that devices may couple to the external combustion engine by means of the driveshaft. The driveshaft rotates about a driveshaft axis passing lengthwise through a center of the driveshaft. At least one first rotatable piston is positioned within the first engine housing, coupled to the driveshaft, and configured to rotate about the driveshaft axis when expansive gas resulting from combustion of a fuel contacts the at least one first rotatable piston. At least one first backstop valve couples to the first engine housing such that the at least one first backstop valve directs expansive gas resulting from combustion of a fuel toward the first rotatable piston, wherein the first engine housing further defines at least one exhaust outlet configured to exhaust used expansive gas resulting from combustion of a fuel. Finally, the engine includes ignition and timing controls coupled to the first engine housing and configured to combust a fuel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view of an external combustion engine embodying features of the present invention; 
         FIGS. 2-6  are schematic views of the external combustion engine as taken along viewing line  2  of  FIG. 1 ; 
         FIG. 7  is a perspective view of the external combustion engine incorporating a second stage of combustion in accordance with features of the present invention; 
         FIG. 8  is a perspective view of the second stage of the external combustion engine taken along line  8 - 8  of  FIG. 7 ; 
         FIGS. 9-13  are schematic views of the external combustion engine as taken along viewing line  3  of  FIG. 8 ; and 
         FIG. 14  is a perspective view of an external combustion engine utilizing a supercharger in accordance with principles of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following discussion, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be obvious to those skilled in the art that the present invention may be practiced without such specific details. Additionally, for the most part, details concerning the means by which a fuel source and oxidizer are introduced into the engine and the like have been omitted inasmuch as such details are not considered necessary to obtain a complete understanding of the present invention, and are considered to be within the skills of persons of ordinary skill in the relevant art. 
     Referring to  FIG. 1  of the drawings, an engine  100  comprises a first engine housing  101 . The first engine housing  101  defines an engine chamber in which additional components of the engine  100  reside and allows those components to move in a rotational manner, as described in more detail below. A person of ordinary skill in the relevant art will understand that the first engine housing  101  may vary in shape and size provided that the first engine housing  101  defines a cavity in which appropriately sized components may operate as described herein. Furthermore, a person of ordinary skill will understand that the first engine housing  101  may be produced of a variety of materials provided that those materials are selected to appropriately accommodate any desired fuel sources with which the engine  100  is used. 
     The engine  100  further comprises a first rotatable piston  103 . In the illustrated embodiment, the driveshaft  106  is positioned near a center of the first engine housing  101  such that the driveshaft  106  may turn on a driveshaft axis  107  passing through a length of the driveshaft  106 , as illustrated in  FIG. 1 . The first rotatable piston  103  couples to the driveshaft  106  such that rotation of the first rotatable piston  103  induces rotation in the driveshaft  106  about the driveshaft axis  107 . The first rotatable piston  103  may vary in diameter. Preferably, a gap remains between the first rotatable piston  103  and the first engine housing  101 . 
     The first rotatable piston  103  comprises a first piston riser  104 , and a first piston riser head  105 . The first piston riser  104  couples to the first rotatable piston  103  and substantially fills the gap between the first rotatable piston  103  and the first engine housing  101 . The first piston riser head  105  comprises a portion of the first piston riser  104  configured to receive a force generated by the combustion of a fuel and an oxidizer (described in more detail below). The first piston riser head  105  comprises a first piston riser head edge  108 . The first piston riser  104  couples to the first rotatable piston  103  such that the first piston riser head edge  108  contacts the first engine housing  101 , or a seal (not shown) between the first engine housing  101  and the first piston riser head edge  108  preventing the passage of gases and other materials between the first piston riser head edge  108  and the first engine housing  101 . For ease of explanation, only one piston riser is shown in  FIG. 1 . A person of ordinary skill in the art will understand that multiple piston risers may couple to the first rotatable piston  103 . 
     The first engine housing  101  further comprises a combustion gas inlet chamber  109 . The combustion gas inlet chamber  109  comprises a portion of the first engine housing  101  configured to direct combustion gases toward the first piston riser head  105 . The combustion gas inlet chamber  109  may vary in size and location according to the use to which the engine  100  is put. The combustion gas inlet chamber  109  further comprises a first backstop valve  110 . In the illustrated embodiment, the first backstop valve  110  comprises a rigid flap hinged at one end so that the first backstop valve  110  will extend into the portion of the first engine housing  101  where the rotatable piston  103  resides. Preferably, an edge of the first backstop valve  110  will contact the first rotatable piston  103  or a seal (not shown) between the first backstop valve  110  and the first rotatable piston  103  when the first piston riser  104  is not causing the operation of the first backstop valve  110  as described below. The first backstop valve  110  displaces into the combustion gas inlet chamber allowing the first piston riser  104  to rotate about the driveshaft axis  107  in the first engine housing  101 . 
     A combustion gas inlet  111  couples to the combustion gas inlet chamber  109 . The combustion gas inlet  111  further couples to the combustion chamber  112 . As illustrated, the combustion chamber  112  comprises an enclosure in which a fuel and an oxidizer combust, generating combustion gases. The combustion chamber  112  is further coupled by any suitable means to fuel and oxidizer tanks embodied here by fuel/oxidizer chamber  113 . A person of ordinary skill in the art will understand that the fuel and the oxidizer enter the combustion chamber through any suitable means. For example, an oxidizer, such as air, could be taken into the engine  100  from the ambient environment utilizing the vacuum pressure generated by the operation of the engine  100 . Alternatively, air could be taken from the ambient environment and pressurized through a turbocharger or supercharger prior to entry into the engine  100 . Similarly, fuel could be pumped from a fuel tank by means of an electric fuel pump. 
     A first exhaust outlet  114  couples to the first engine housing  101 . The first exhaust outlet  114  provides a pathway for combustion gases to exit the first engine housing  101  following the completion of the engine cycle (described in more detail below). A first engine housing plate (not shown) couples to the first engine housing  101  at engine housing flanges  120 . In this manner, the presently exposed interior of the first engine housing  101  is sealed from the atmosphere preventing the dissipation of the combustion gases and directing the combustion gas energy directly onto the first piston riser head  105 . 
     Timing and ignition controls are located such that the first piston riser  104  controls the timing of ignition of the fuel source in the combustion chamber. 
     Finally, the first engine housing  101  couples to first engine mounts  130 . First engine mounts  130  couple the engine  100  to a location or to an object so that the engine  100  may further couple to a device needing mechanical power. 
     Referring now to  FIGS. 2  thru  6 , this collection of figures illustrates operational positions of certain components of the engine during the operational cycle. In  FIGS. 2-6 , the movement of combustion gases is indicated by the directional arrow. Beginning with  FIG. 2 , combustion of the fuel source occurs in the combustion chamber  112  (not shown in  FIG. 2 ), the resultant expansion of combustion gases resulting from the combustion process is directed into the combustion gas inlet  111 . At this stage, the first backstop valve  110  remains in position A, preventing the combustion gases from bypassing the first piston riser head  105  of the first piston riser  104  through the first exhaust outlet  114 . As such, the engine  100  begins a power stroke as the combustion gases exert their energy against the first piston riser head  105 , rotating the first rotatable piston  103  and the driveshaft  106  about the driveshaft axis  107  (not shown in  FIG. 2 ). 
     Moving now to  FIG. 3 , there is shown continued movement of the first rotatable piston  103 , due to the force exerted by the expansion of the combustion gases against the first piston riser head  105 . As the process continues, the combustion gases rotate the first rotatable piston  103  such that the first piston riser  104  lifts the first backstop valve  110 . The beginning of this process is illustrated in  FIG. 4 . The first piston riser  104  is sized such that the first backstop valve  110  will move to close off the combustion gas inlet chamber  109 , preventing the combustion gases from passing back into the combustion chamber. At this stage, the last remaining expansive energy resulting from combustion is maintained against the first piston riser head  105  due to the first piston riser  104  blocking the first exhaust outlet  114 . Preferably, the first piston riser  104  is sloped such that the transition of the first backstop valve  110  from position A as illustrated in  FIGS. 2 and 3  to position B as illustrated in  FIG. 5  does not generate undue force on either the first backstop valve  110 , or the first piston riser  104 , thus prolonging the life of both elements. 
     Referring now to  FIG. 5 , as the first rotatable piston  103  continues to rotate about the driveshaft axis  107  (not shown in  FIG. 5 ), the first piston riser  104  pushes the first backstop valve  110  fully into position B barring passage of combustion gases from a face of the first piston riser head  105  into the combustion gas inlet chamber  109 . Furthermore, as the first piston riser  104  completes a revolution, it begins to decrease the volume available for the combustion gases used at the start of the cycle. These used combustion gases are pushed through the first exhaust outlet  114 . As shown in  FIG. 6 , once the first piston riser  104  completes its revolution, the backstop valve moves back to position A, at this point the cycle begins anew with combustion of additional fuel in the combustion chamber  112  (not shown in  FIG. 6 ). 
     Referring now to  FIG. 7 , an engine  200  comprises the first engine housing  101  coupled to a second engine housing  201 . The first engine housing  101  couples to the second engine housing  201  at engine housing flanges  150 . As illustrated, the first exhaust outlet  114  directs the used combustion gases from the first engine housing  101  into the second engine housing  201  at a location which allows combustion gases to pass from the first engine housing  101  to the second engine housing  201  after combustion gases have expanded and caused the rotation of the first rotatable piston  103 . Thus, the combustion gases enter a second stage (described below) allowing the external combustion engine to process the effects of combustion a second time, increasing the efficiency of the motor for each act of combustion. 
     All components of the engine  100  described above with respect to  FIGS. 1-6  and illustrated in  FIG. 7  retain their numerical designation in the engine  200  and operate as previously described. Similar to the first engine housing  101  described above, the second engine housing  201  couples to second engine mounts  140 . Second engine mounts  140  allow the engine  100  to couple to a location or device so that the engine  200  may couple to a device needing mechanical power. 
     Referring to  FIG. 8  of the drawings, the second engine housing  201  defines an engine chamber in which additional components of the engine  200  reside and allows those components to move in a rotational manner, as described in more detail below. A person of ordinary skill in the relevant art will understand that the second engine housing  201  may vary in shape and size provided that the second engine housing  201  defines a cavity in which appropriately sized components may operate as described herein. Furthermore, a person of ordinary skill will understand that the second engine housing  201  may be produced of a variety of materials provided that those materials are selected to appropriately accommodate any desired fuel sources with which the engine  100  is used. 
     The engine  200  further comprises a second rotatable piston  203 . In the illustrated embodiment, the driveshaft  106  shown in  FIG. 1  passes into a center of the second engine housing  101  such that the driveshaft  106  may turn on a driveshaft axis  107  passing through a length of the driveshaft  106 , as illustrated in  FIG. 8 . A person of ordinary skill in the art will understand that the driveshaft  106  may comprise one driveshaft passing through both the first engine housing  101  and the second engine housing  201 , or it may comprise two separate driveshafts coupled together. The second rotatable piston  203  couples to the driveshaft  106  such that rotation of the second rotatable piston  203  induces rotation in the driveshaft  106  about the driveshaft axis  107 . The second rotatable piston  203  may vary in diameter. Preferably, a gap remains between the second rotatable piston  203  and the second engine housing  201 . 
     The second rotatable piston  203  comprises a second piston riser  204  and a second piston riser head  205 . The second piston riser  204  couples to the second rotatable piston  203  and substantially fills the gap between the second rotatable piston  203  and the second engine housing  201 . The second piston riser head  205  comprises a portion of the second piston riser  204  configured to receive a force generated by the combustion of a fuel and an oxidizer (described in more detail below). The second piston riser head  205  comprises a second piston riser head edge  208 . The second piston riser  204  couples to the second rotatable piston  203  such that the second piston riser head edge  208  contacts the second engine housing  201 , or a seal (not shown) between the second engine housing  201  and the second piston riser head edge  208 . This prevents the passage of gases and other materials between the second piston riser head edge  208  and the second engine housing  201 . For ease of explanation, only one piston riser is shown in  FIG. 8 . A person of ordinary skill in the art will understand that multiple piston risers may couple to the second rotatable piston  203 . 
     The second engine housing  201  further comprises an exhaust gas inlet chamber  209 . The exhaust gas inlet chamber  209  comprises a portion of the second engine housing  201  configured to direct the exhaust gases exhausted from the first engine housing  101  toward the second piston riser head  205 . The exhaust gas inlet chamber  209  may vary in size and location according to the use to which the engine  200  is put. The exhaust gas inlet chamber  209  further comprises a second backstop valve  210 . In the illustrated embodiment, the second backstop valve  210  comprises a rigid flap hinged at one end so that the second backstop valve  210  will extend into the portion of the second engine housing  201  where the second rotatable piston  203  resides. Preferably, an edge of the second backstop valve  210  will contact the second rotatable piston  203  or a seal (not shown) between the second backstop valve  210  and the second rotatable piston  203  when the second piston riser  204  is not causing the operation of the second backstop valve  210  as described below. The second backstop valve  210  displaces into the exhaust gas inlet chamber  209  allowing the second piston riser  204  to rotate about the driveshaft axis  107  in the second engine housing  201 . 
     The first exhaust gas outlet  114  of  FIG. 1  couples to the exhaust gas inlet chamber  209 . 
     A second exhaust outlet  214  couples to the second engine housing  201 . The second exhaust outlet  214  provides a pathway for combustion gases to exit the second engine housing  201  following the completion of the engine cycle (described in more detail below). A second engine housing plate (not shown) couples to the second engine housing  201  at engine housing flanges  150 . In this manner, the presently exposed interior of the second engine housing  201  is sealed from the atmosphere preventing the dissipation of the combustion gases and directing the combustion gas energy directly onto the second piston riser head  205 . 
     Referring to  FIGS. 9-13 , this collection of figures illustrates operational positions of certain components of the engine  100  during the operational cycle of the second stage described above with respect to  FIGS. 7 and 8 . In  FIGS. 9-13 , the movement of combustion gases is indicated by the directional arrow. Initially, the engine completes the cycle illustrated in  FIGS. 2-6  generating exhaust gases from the first engine housing  101  (not shown). Beginning with  FIG. 9 , exhaust gases exhausted from the first engine housing  101  (not shown) pass through the first exhaust gas outlet  114  and into the exhaust gas inlet chamber  209 . At this stage, the second backstop valve  210  remains closed preventing the exhaust gases from moving away from the second piston riser head  205  of the second piston riser  204 . As such, the engine  100  begins a power stroke as the exhaust gases exert their energy against the second piston riser head  205 , rotating the second rotatable piston  203  and the driveshaft  106  about the driveshaft axis  107 . 
     Moving now to  FIG. 10 , there is shown continued movement of the second rotatable piston  203 , due to the force exerted by the expansion of the exhaust gases against the second piston riser head  205 . As the process continues, the exhaust gases rotate the second rotatable piston  203  such that the second piston riser  204  lifts the second backstop valve  210 . The beginning of this process is illustrated in  FIG. 11 . The second piston riser  204  is sized such that the second backstop valve  210  will close off the exhaust gas inlet chamber  209 , preventing the exhaust gases from bypassing the second piston riser head  205  through the second exhaust outlet  214 . At this stage, the last remaining expansive energy resulting from combustion is maintained against the second piston riser head  205  due to the second piston riser  204  blocking the second exhaust outlet  214 . Preferably, the second piston riser  204  is sloped such that the transition of the second backstop valve  210  from position C as illustrated in  FIGS. 9 and 10  to position D as illustrated in  FIG. 12  does not generate undue force on either the second backstop valve  210 , or the second piston riser  204 , thus prolonging the life of both elements. 
     Referring now to  FIG. 12 , as the second rotatable piston  203  continues to rotate about the driveshaft axis  107 , the second piston riser  204  pushes the second backstop valve  210  shut, barring passage of exhaust gases from a face of the second piston riser head  205  into the exhaust gas inlet chamber  209 . Furthermore, as the second piston riser  204  comes close to completing a revolution, it begins to decrease the volume available for the exhaust gases used at the start of the cycle. These used exhaust gases are pushed through the second exhaust outlet  214  by the continued rotation of the second rotatable piston  203 . As shown in  FIG. 13 , once the second piston riser  204  completes a revolution, the second backstop valve moves back to position D, at this point the cycle begins anew with entry of new exhaust gases into the exhaust gas inlet chamber  209  from the first exhaust outlet  114 . 
     By the use of the present invention, numerous advantages are produced over prior art engines. For example, prior art internal combustion engines must operate at high pressures, and the components must be extremely strong, necessitating heavy overbuilt components, or lightweight expensive components. The engine of the present invention operates at lower operating pressures; thus, there is no need for heavy components that decrease the efficiency and use of the engine, or lightweight components that drive up the cost of the engine limiting the number of applications to which it can reasonably be applied. Furthermore, lower operating pressures allow a single embodiment of the present invention to operate at varying pressures on varying fuel sources, necessitating only minor modifications to timing and ignition to transition the engine from a first fuel source, to a second fuel source that is incompatible with the first fuel source. Finally, the present invention operates without the need of a crankshaft, or camshaft; thus, the engine operates without the need for traditional components of the internal combustion engine which significantly reduce the efficiency of the engine. Without these drags on efficiency, the engine of the present invention significantly increases the amount of power that can be produced from the same volumetric consumption of fuel. 
     It is understood that the present invention may take many forms and embodiments. Accordingly, several variations may be made in the foregoing without departing from the spirit or scope of the invention. For example, the size, location, and number of combustion chambers, and pistons may vary and be tailored to individual applications of the engine. Furthermore, the engine may be operated at varying operating pressures and on varying fuel sources. 
     Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered obvious and desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.