Abstract:
This invention presents a method to improve the volumetric efficiency of a reciprocating internal combustion engine using a common transfer port between the exhaust and intake port. The engine employs a poppet valve as part of the intake and exhaust valve to control the flow from the transfer port into the combustion chamber. Two plate type valves outside of the combustion chamber are located at both ends of the transfer port to control the flow coming from the intake and out the exhaust. The timing for opening and closing of the poppet type valve is regulated to remain open for a longer duration which provides complete evacuation of air in the exhaust stroke. The ejector effect from the exhaust flow through the transfer port draws a vacuum into the cylinder. When the exhaust plate closes, the vacuum diverts the intake into the cylinder.

Description:
BACKGROUND OF INVENTION 
       [0001]    This invention relates to internal combustion engines and more particularly to an improvement in valve mechanism to direct intake and exhaust flow in and out of the engine. 
         [0002]    Poppet type valves are most widely used valves to open and close combustion chamber. A conventional engine uses at least two individual poppet valves, one for the intake and another for exhaust, to control the engine gas exchange process. They operate in timed relation to the rotation of the engine crank shaft. Other types of valves such as rotary or sleeve valves, and in some instance a single poppet valve is also used to control the flow. There are advantages and disadvantages with any of these systems. Obtaining a positive sealing for the rotary and sleeve type valve for different speed range is still a challenge. Poppet type valves ensure positive sealing, however when individual poppet valve is used for intake and exhaust, it reduces the size of the gas passage, increases weight, and requires more energy to drive, to name a few. The use of single poppet valve is advantageous from the aspect of lightness and simplicity of construction, valve temperature control, and combustion chamber design. 
         [0003]    The idea of an internal combustion engine having a single poppet type valve to control intake and exhaust flow of the combustion chamber is very well recognized. It dates back to as early as Jun. 16, 1895, U.S. Pat. No. 5,428,46 to Diesel, to the present time Pub. Date. Jul. 7, 2011, Pub. No. US2011/0162607 A1 to Joel et al. Most of these inventions are adaptable for use under constant speed condition where it is not necessary to control the intake and exhaust flow and timing in relation to the speed change. A few of the inventions, such as U.S. Pat. No. 2,107,389 and U.S. Pat. No. 40,755,986, provide mechanics to control the intake and exhaust flow before they enter the combustion chamber through the poppet valve. However, the intake timing and the size of gas flow passage directly depends on the timing and the size of the exhaust, hindering the optimization of valve timing. There are other limiting factors of single poppet type valve, such as the placement of the spark plug and the fuel injector system using conventional poppet type valves. 
         [0004]    It is therefore an object of the invention to provide a combination of poppet type and unique plate type of valve system to minimize drawbacks of a current valve system and improve upon it. 
         [0005]    Another object of our invention is to provide scavenging of the intake flow and simultaneously provide cooling of the poppet valve and the exhaust means, employing a common air chamber. 
         [0006]    A further object of our invention is to provide a poppet type valve engine which is mechanically similar to standard practice and thus variable valve timing can be employed. 
         [0007]    It is a general object of the present invention to improve internal combustion engine design. 
       SUMMARY OF INVENTION  
       [0008]    The invention involves internal combustion engine, generally characterized by two-stroke or four-stroke principle, comprising intake, compression, power, and exhaust cycle of operation. The engine includes a piston cylinder having a combustion chamber and a piston mounted therein sealingly engaged with the walls of the combustion chamber. Air and combustible fuel, such as gasoline or diesel, are drawn into or injected into the combustion chamber, commonly known as intake. The charged combustible mixture is compressed by the piston and ignited, known as compression and power. Once energy is extracted from the combust mixture, a valve between the combustion chamber and the exhaust path opens to release the products of combustion out of the combustion chamber, known as exhaust. 
         [0009]    With this innovation, both the intake and exhaust gas exchange process of the combustion chamber is collectively controlled using poppet type valves. A single poppet type valve on top of the combustion chamber permits larger gas passage area and a better intake swirl for better combustion characteristic. When it is desired to place the spark plug of spark ignition engine or the fuel injector of diesel engine on top of the combustion chamber, more than one poppet valve can be used where they all open and close collectively to control the gas exchange of the combustion chamber. In a single poppet type valve engine configuration the spark plug or the fuel injector can be placed through the center of the poppet using modified poppet valve to position them on top of the combustion chamber. 
         [0010]    For both combustion chamber designs, a common transfer port adjacent to the combustion chamber communicates between the chamber and the intake and exhaust ducts, which are communicably aligned with the transfer port. A rotary or reciprocating plate type valve opens and closes the intake and exhaust ducts to and out from the transfer port in order to guide the gas flow. According to the innovation in an embodiment, the plates operate with sufficient mechanical clearance so no lubrication is required. 
         [0011]    During the normal combustion process, the exhaust plate valve opens to allow the exhaust gases to escape at the end of power stroke. Then the poppet valve system open to allow the cylinder gases to exhaust into the transfer port and then out past the exhaust plate. At the end of the exhaust cycle, the poppet valve remains open and the intake plate opens to allow the exhaust to fully evacuate. The ejector effect caused by the intake air flow through the transfer port to the exhaust plate will draw a vacuum inside the cylinder. The exhaust plate closes and diverts the intake air into the cylinder. 
         [0012]    Accordingly, one embodiment is directed to a flow control mechanism for an internal combustion reciprocating piston engine. The engine includes a combustion chamber, a common transfer port adjacent to the combustion chamber, an intake duct directly communicating with the transfer port and an exhaust duct extending out from the transfer port to communicate flow into and out of the transfer port, a first valve positioned inside the combustion chamber for controlling flow between the transfer port and the combustion chamber, a second valve for controlling flow between the intake duct and the transfer port, and a third valve for controlling flow between the exhaust duct and the transfer port, wherein the second valve and the third valve are independently controlled. 
         [0013]    Other objects and features of the invention will be more fully understood from reading the drawings and description hereinafter. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0014]      FIG. 1  is the sectional view of a prototypical poppet valve, cam, plate valves, and drive system mounted within a prototypical housing according to the instant invention. 
           [0015]      FIG. 2  is a section view along the line L 1  of  FIG. 1  showing the prototypical valve plate and poppet valve position in relation to the transfer port and combustion chamber. 
           [0016]      FIG. 3  shows an exploded view of  FIG. 1  without the housing. 
           [0017]      FIG. 4  shows an exemplary timing of the exhaust and intake plate relative to the prototypical cam of the instant invention. 
           [0018]      FIG. 5  is a side view of the prototypical valve plate configuration. 
           [0019]      FIG. 6  is a side view of the prototypical cam configuration used for the poppet valve actuation. 
           [0020]    FIG.  7 A—is fragmented view showing the poppet and plate valve positions during end of a power phase operation cycle of the engine with an exhaust plate open. 
           [0021]      FIG. 7B  is fragmented view showing the poppet and plate valve positions during end of an exhaust cycle, the poppet valve remains open and intake plate opens through open exhaust plate to allow the exhaust to fully evacuate an exhaust operation cycle of the engine. 
           [0022]      FIG. 7C  is fragmented view showing the poppet and plate valve positions during an intake operation cycle of the engine with exhaust plate closed. 
           [0023]      FIG. 7D  is fragmented view showing the poppet and plate valve positions during a compression power phase operation cycle of the engine. 
           [0024]      FIG. 8  shows another exemplary configuration of the combustion chamber with multiple poppet valves. 
           [0025]      FIG. 9  is a cross section view similar to  FIG. 1  showing substitute modification of the rotating plate valve mechanism with an exemplary reciprocating plate valve mechanism. 
           [0026]      FIG. 10  shows an exemplary configuration of the reciprocating plate valve. 
           [0027]      FIG. 11  is a side view of an exemplary cam configuration to actuate the reciprocating plate valve. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    The following detail description with appended drawings helps explain the invention further. Same numerals present identical elements of the embodiments. Terms such as top, bottom, horizontally and vertically describes an orientation relative to the drawings only and do not necessarily correspond to an actual engine plane in which these parts may be incorporated. 
         [0029]    Referring to the drawings, a first embodiment of an internal combustion engine of the invention is seen in  FIGS. 1-6  and is generally designated by the numeral  10 . A second embodiment the engine of invention is seen in  FIG. 8  and is designated by the numeral  10 ′. A third embodiment the engine of invention is seen in  FIG. 9-11  and is designated by the numeral  10 ″. For the present invention, engine frame and crank shaft structures are conventional and therefore not shown. Unique aspects of the invention reside the engine head structure which incorporates an unconventional structure and method to control the intake and exhaust flow in and out of the engine  10 ,  10 ′, and  10 ″. 
         [0030]    The engine  10  includes a central valve housing member  12  having a recessed intake face  14  and a recessed exhaust face  16 . A non-centrally disposed transverse port  18  extends from the intake face  14  to the exhaust face  16  of the central valve housing member  12 . A piston cylinder  26  is positioned within the central valve housing member  12  and operably in communication with transfer port  18 . Upper end of the cylinder  26  forms a combustion chamber  24  inside which combusted fuel discharges in a conventional systems. A reciprocating piston  28  is operably disposed in the cylinder  26 . 
         [0031]    The combustion chamber  24  is opened and closed to the transfer port  18  by means of a single poppet valve  36  constructed with a head  38  and a shaft  40 . The valve head  38  seats against a valve seat  34  in the piston cylinder  26 . In accordance with the invention, the poppet valve  36  opens and closes the combustion chamber  24  by means of a cam  20  in operable connection with shaft  40  and stays close throughout combustion and power stroke by means of a spring  52  connected to the shaft  40  of the poppet valve  36 . A central transverse opening  42  extends from the intake face  14  through to the exhaust face  16  of the housing  12  and serves to receive a cam shaft  32  and sealed using sealing element  66  and  67  connected to hub  64  and  65 , respectively. It is to be understood that the poppet valve  36  can be actuated using means other than a spring and cam mechanism such as desmodromic, solenoid, or electrical actuation. 
         [0032]    Two separate rotary plate valves of similar structure, intake plate valve  46  and exhaust plate valve  56 , control the intake and exhaust flow through the transfer port  18 . In the rotary form, the semicircular plate valves  46  and  56  are preferably thin and lightweight, and have a radial peripheral opening  62  and  63  ( FIG. 4 ), respectively, to communicate with the transfer port  18  as seen in  FIG. 2 . The plate valves  46  and  56  are mounted on the camshaft  32  using two rotary hubs, intake rotary hub  48  and exhaust rotary hub  58 . The cam shaft  32  and the hubs  48  and  58  can include complementary keyed structure to maintain relationship to the cam  20 . This also helps to prevent single valve rotation due to vibration. In this configuration, the axis of rotation of the plate valves  46  and  56  is in the same line with the axis of rotation of the cam  20 . A mechanical or electrical mechanism can be incorporated into the hubs  48  and  58 , to change the timing of the intake plate  46  and exhaust plate  56  in accordance with timing of the poppet valve  36 . Other structures are contemplated to adjust or set the timing of operation of the engine. Changing the timing based on the speed of the engine or other sensor controls can improve efficiency of the engine. For example, a centrifugal mechanism can be used to the change the plate timing as the engine speed changes. With this invention, the camshaft  32  axis of rotation is spaced parallel to the crankshaft axis of rotation. 
         [0033]    Two separate housing mating plates of similar structure, an intake housing mating plate  44 , and an exhaust housing mating plate  54 , are configured to enclose the intake valve plate  46  and exhaust valve plate  56 . Both include a central annular bearing  64  and  65 , respectively, connected therein to rotatably receive the cam shaft  32  therein. Each of the housing mating plates  44  and  54  has a respective non central port  50  and  60 . When the intake housing mating plate  44  connects to the central valve housing  12  in a way that are communicably aligned with the transverse port  18 , they collectively create intake flow path into the combustion chamber  24 . Similarly, when the exhaust housing mating plates  54  connects to the central valve housing  12  in a way that are communicably aligned with the transverse port  18 , they collectively create exhaust flow path out of the combustion chamber  24 . 
         [0034]    To describe the timing sequence of the intake and exhaust flow, as shown in  FIG. 7  A-D, start with the piston  28  positioned at 90 degrees before the upper end of the cylinder  26 , commonly refer as top dead center. In this piston  28  position, as shown in  FIG. 7A , the poppet valve  36  is open to exhaust the combusted gases out of the chamber  24 . At this time in the cycle, the exhaust plate valve  56  is open to clear the exhaust gases out of the transfer port  18 . The intake plate valve  46  is closed to prevent any exhaust transfer to the intake duct  50 . As shown in  FIG. 7B , the intake plate opens to start intake flow and to assist the exhaust evacuation from the transfer port  18 . As it is shown in  FIG. 4 , there is an overlap between the intake plate  46  opening  62  (opening position) and exhaust plate  56  opening  63  (closing position) to completely clear the exhaust out of the combustion chamber  24  and the transfer port  18 . The flow and the position of the plate valves  46  and  56  and the poppet valve  36  during this cycle are seen in  FIG. 7B . 
         [0035]    As shown in  FIG. 7C , intake cool air passes through the intake port  50  into the transfer port  18  and finally to the combustion chamber  24 . The expelling of cool air passing the poppet valve  36  and contacting the exhaust plate valve  56  in area of the transfer port  18  reduces the temperature of the components. This cooling effect reduces detonation on the poppet valve  36  and the incidence of nitrogen oxide formation. Consequently, the temperature increase of the intake air help to achieve better combustion characteristics. 
         [0036]    The poppet valve  36  starts to close as the volume of air in the combustion chamber  24  reaches a required amount. An amount of fuel is injected into the combustion chamber  24  by conventional means. The piston  28  starts traveling towards top dead center and the charge of air begin to compress. The position of the plate valves  46  and  56  and the poppet valve  36  during this cycle are shown in  FIG. 7D . Once compresses, the charge of combustible mixture is ignited in conventional way. Using single poppet type valve system gasoline type of engine, the ideal position of the ignition system is in the center of the poppet valve head  38 . For diesel type of engine with single poppet valve system, the ideal location of the fuel injection point is in the center of the poppet valve head  38 . 
         [0037]    The ignition of the combustible mixture produces hot gases of combustion that expand rapidly and push the piston  28  back towards bottom dead center. The poppet valve is valve  36  is sealed during the compression, ignition, and expansion of the combustible mixture, against the valve seat  34 . The poppet valve  36  starts to open once the volume of the combustion mixture reaches the maximum. Consecutively, the burnt gases are exhausted through the transfer port  18 . The piston  28  returns to the beginning of its cycle at top dead center. The poppet valve  36  is fully open on the exhaust stroke and remains fully open during the air intake stroke and only closes when it is desired to initiate compression, ignition and expansion. This is achieved by using a special cam  20  profile as shown in  FIG. 6 . The opening and closing position and duration of the poppet valve  36  is determined by the requirement of air and speed of the engine. Since the plate valves  46  and  56  and the poppet valve  36  mechanism follows a traditional cam system, conventional variable valve timing mechanism can be incorporated. 
         [0038]    In the embodiment seen in  FIG. 8 , the engine  10 ′ shows an exemplary alternative design with two poppet valves  36  instead of one, nested within the housing  22 . In accordance with the invention, both poppet valves  36  collectively open and close the combustion chamber  24  by means of cam  30  and stay close throughout the combustion and power stroke by means of springs  52 . The cam  30  can have exact same timing profile to open and close both poppet valves simultaneously or they can vary slightly depending on the design need. The other operations of engine  10 ′ is similar to engine  10 . 
         [0039]    In the embodiment seen in  FIGS. 9-11 , the engine  10 ″ shows an exemplary alternative design using an intake slide valve  70  and exhaust slide valve  80  instead of the rotating plate valves  46  and  56 . In accordance with the invention, plate valves  70  and  80  open and close the intake and exhaust duct  50  and  60  respectively by means of cams  72  and  82  and stay close throughout the compression, ignition, and expansion strokes by means of springs  78 . In this embodiment, the intake housing mating plate  74  and the exhaust housing mating plate  84  are configured with opening  76  and  86 , respectively to house the cam and spring actuating mechanism. The actuation mechanism is typical of cam actuation mechanism and allows the flexibility of incorporating variable valve timing if desired. 
         [0040]    The automotive industry is under mandates to increase the fuel efficiency of the internal combustion engine. The purpose of the instant invention design is to develop an engine that has higher fuel efficiency while maintaining the power output. One way of achieving this would be increasing the engine&#39;s thermal and volumetric efficiency. Our analysis suggest that using single poppet type valves to control the air in and out of the cylinder through the transfer port will significantly increases the engines volumetric efficiency. 
         [0041]    For both instance of single or multiple poppet valves, where the poppet valves open and close collectively, the exhaust evacuates much more efficiently while the poppet valve stays open for longer period of time. In conventional engine the exhaust valve starts to close about 60 degrees before the intake starts to open leaving some exhaust gas in the cylinder. When a single poppet valve or multiple poppet valves are used collectively, the system increases the air flow area for the exhaust, thus overcoming the normal situation where the exhaust valves are generally smaller than the intake, which is a limiting factor of efficiently exhausting the combusted gases. The benefit of a single valve design is that it creates a chamber that is more hemispheric and the intake charge has high swirl to initiate better combustion. 
         [0042]    When complete exhaust is desired, the intake plate valve can open slightly before the exhaust plate valve closing so there is an overlap of flow between the intake and the exhaust duct. The incoming fresh air scoops out any remaining exhaust in the combustion chamber through the transfer port and out through the exhaust. Alternatively, to control the nitrogen oxide formation, it is sometime desirable to have some exhaust gas inside the combustion chamber. Separate intake and exhaust control and the ability to vary the timing make it easier to achieve that. Using the plate type valve in the intake and exhaust duct, the timing can be varied so the exhaust closes before the intake opens and thus some of the intake air gets mixed with the exhaust gas trapped in the transfer port. 
         [0043]    The above described embodiments are set forth by way of example and are not for purpose of limiting the present invention. It will be readily apparent to those skilled in the art that obvious modifications, derivations and variations can be made to the embodiment without departing from the scope of the invention. Accordingly, the claims appended hereto should be read in their full scope including any such modifications, derivations and variations.