Abstract:
A two stroke internal combustion engine, comprising one or more power cylinders with intake and exhaust ports and a source of scavenging of the power cylinders, with improvements, including use of double-sided cylinders with upper and lower cavities used as power or pumping cavities connected to each other in different combinations; multi-bank engine structures with cavities of the cylinders in the first and second bank used as power or pumping cavities, connected to each other in different combinations.

Description:
CROSS-REFERENCE TO RELATED PATENTS AND APPLICATIONS  
         [0001]    Two Stroke Internal Combustion Engine. Patent of Russian Federation No. 2143077, Int. Cl. F02 B 33/00, registered Dec. 20, 1999, published in 1999, Bul. No. 35, priority date Jun. 22, 1998, application No. 98111885/06.  
         REFERENCES CITED  
         [0002]    1. Two Stroke Internal Combustion Engine. RU Patent No. 2063524, Int. Cl. F02 B 33/22, published in 1996, Bul. No. 19.  
           [0003]    2. Two Stroke Internal Combustion Engine. U.S. Pat. No. 2,522,649, US Cl. 123-70, 1950.  
           [0004]    3. Radial Two Stroke Internal Combustion Engine with Piston Scavenging Pumps. SU Patent No. 54112, Int. Cl. F02 B 33/22, 75-22, 1939.  
         INFORMATION SOURCES, TAKEN INTO CONSIDERATION  
         [0005]    1. RU Patent No. 2063524 Cl, 10.07.96  
           [0006]    2. U.S. Pat. No. 2,522,649 A, 19.09.50  
           [0007]    3. SU Patent No. 54112 A, 28.02.39  
           [0008]    4. SU Patent No. 2472 A, 31.03.27  
           [0009]    5. U.S. Pat. No. 3,880,126 A, 29.04.75  
           [0010]    6. U.S. Pat. No. 5,265,564 A, 30.11.93  
           [0011]    7. GB Patent No. 994371 A, 07.11.61  
         BACKGROUND OF THE INVENTION  
         [0012]    This invention relates to further development of two stroke internal combustion engines (from hereinafter referred to as ‘TSICE’), which have one or more power cylinders with intake and exhaust ports, and a source of scavenging of the power cylinders.  
           [0013]    Some terms and abbreviations used in the following description of previous art and present invention are defined below.  
           [0014]    Pistons of TSICE move reciprocally within two limits, conventionally named as ‘top dead center’ and ‘bottom dead center’. From hereinafter top dead center is referred to as ‘TDC’ and bottom dead center as ‘BDC’.  
           [0015]    Cavity of a cylinder, which is a space within the walls of the cylinder limited by a face of a piston, from hereinafter is referred to as ‘cavity’.  
           [0016]    In a double-sided cylinder, a piston has two faces, front and rear, which form two cavities within the walls of the cylinder on the opposite sides of the piston. In further description, due to the upright position of the cylinders on the drawings, the said cavities are referred to as ‘upper cavity’ and ‘lower cavity’.  
           [0017]    The main problems, known as deficiencies of TSICE, are the partial mixing of burned gases with the fresh air-fuel mixture, and the loss of some fresh air-fuel mixture through the exhaust ports at the time of scavenging.  
           [0018]    As long as improvements can be achieved, reducing these problems, there is a chance to increase power per liter of displacement.  
           [0019]    The so-called direct-flow scavenging/charging of the power cylinders has to be organized, when fresh air-fuel mixture fills up the cavity of the power cylinder starting from the intake port towards the exhaust port, so that burned gases always remain in the way of the air-fuel mixture to the exhaust port with minimum mixing.  
           [0020]    One of the ways to achieve the direct-flow scavenging/charging is to have two power cylinders, connected to each other with a common combustion chamber, where one of the cylinders has the intake port, and another has the exhaust port, as it is in RU Patent No. 2,063,524. Scavenging/charging starts in one cylinder and ends in the other, most importantly, cleaning the area of combustion chamber of burned gases and providing unidirectional displacement of burned gases with fresh air-fuel mixture. RU Patent No. 2,063,524 uses a pumping cylinder as a source of scavenging/charging of power cylinders.  
           [0021]    TSICE, according to U.S. Pat. No. 2,522,649, comprises power and pumping cylinders with intake and exhaust ports, where the exhaust port of the pumping cylinder is connected to the intake port of the power cylinder by a channel.  
           [0022]    TSICE, according to RU Patent No. 2,063,524, comprises the first power cylinder with an intake port, connected to a pumping cylinder, and the second power cylinder with an exhaust port, said cylinders having a common combustion chamber and pistons connected each to its own crank, with the crank of the second piston having advanced crank angle against the crank of the first piston, enabling advanced opening and closing of the exhaust port in relation to the intake port.  
           [0023]    A common drawback of the above named patents is the use of an additional cylinder, piston and crank solely for the purpose of scavenging/charging of another cylinder, which increases the size and weight of the engine and reduces power per liter of displacement.  
           [0024]    According to the totality of distinctive characteristics, the engine construction of U.S. Pat. No. 2,522,649 is taken as the closest prototype of present invention.  
           [0025]    Multi-bank structures of TSICE, as in the SU Patent No. 54112, are also considered.  
         BRIEF SUMMARY OF THE INVENTION  
         [0026]    Presented is TSICE with object to increase power per liter of displacement, which is achieved by use of double-sided cylinders with upper and lower cavities used as power or pumping cavities, connected to each other in different combinations, and use of multi-bank engine structure, reducing the number of cranks and pistons and size and weight of the engine.  
       
    
    
     DRAWING FIGURES  
       [0027]    [0027]FIG. 13 shows single-row double-bank TSICE comprising power cylinder in the first bank and double-sided cylinder in the second bank with pumping cavity, connected to a supercharger.  
         [0028]    [0028]FIGS. 15A, 15B show double-row double-bank TSICE comprising two power cylinders in the first bank and two double-sided cylinders in the second bank with pumping cavities, connected to a supercharger, and piston cranks having angular deviation 180° against each other.  
         [0029]    [0029]FIGS. 16A, 16B show double-row double-bank TSICE comprising two pumping cylinders in the first bank, connected to a supercharger, and two double-sided cylinders in the second bank with piston cranks having angular deviation 180° against each other. 
     
    
     REFERENCE NUMERALS IN DRAWINGS  
       [0030]    [0030] 1  First cylinder of the first bank  
         [0031]    [0031] 2  Second cylinder of the first bank  
         [0032]    [0032] 5  First cylinder of the second bank  
         [0033]    [0033] 6  Second cylinder of the second bank  
         [0034]    [0034] 9  Piston of cylinder  1   
         [0035]    [0035] 10  Piston of cylinder  2   
         [0036]    [0036] 13  Piston of cylinder  5   
         [0037]    [0037] 14  Piston of cylinder  6   
         [0038]    [0038] 17  Upper cavity of cylinder  1   
         [0039]    [0039] 19  Upper cavity of cylinder  2   
         [0040]    [0040] 25  Upper cavity of cylinder  5   
         [0041]    [0041] 26  Lower cavity of cylinder  5   
         [0042]    [0042] 27  Upper cavity of cylinder  6   
         [0043]    [0043] 28  Lower cavity of cylinder  6   
         [0044]    [0044] 33  Intake port of cavity  17   
         [0045]    [0045] 35  Intake port of cavity  19   
         [0046]    [0046] 41  Intake port of cavity  25   
         [0047]    [0047] 42  Intake port of cavity  26   
         [0048]    [0048] 43  Intake port of cavity  27   
         [0049]    [0049] 44  Intake port of cavity  28   
         [0050]    [0050] 49  Exhaust port of cavity  17   
         [0051]    [0051] 51  Exhaust port of cavity  19   
         [0052]    [0052] 57  Exhaust port of cavity  25   
         [0053]    [0053] 58  Exhaust port of cavity  26   
         [0054]    [0054] 59  Exhaust port of cavity  27   
         [0055]    [0055] 60  Exhaust port of cavity  28   
         [0056]    [0056] 69  Transverse partition  
         [0057]    [0057] 70  Crank of piston  9   
         [0058]    [0058] 71  Crank of piston  10   
         [0059]    [0059] 74  Piston rod  
         [0060]    [0060] 76  Connecting rod  
         [0061]    [0061] 77  Crank-and-connecting-rod assembly  
         [0062]    [0062] 78  Oil-filled crankcase  
         [0063]    [0063] 79  Spark plug  
         [0064]    [0064] 80  High-pressure direct fuel injector  
         [0065]    [0065] 91  Supercharger  
         [0066]    [0066] 92  Engine intake manifold  
         [0067]    [0067] 98  Self-acting suction valve  
         [0068]    [0068] 100  Fuel pipeline  
         [0069]    [0069] 101  Low-pressure external fuel injector  
         [0070]    [0070] 103  Channel, connecting cavities  17  and  25   
         [0071]    [0071] 104  Channel, connecting cavities  17  and  26   
         [0072]    [0072] 105  Channel, connecting cavities  17  and  28   
         [0073]    [0073] 109  Channel, connecting cavities  19  and  26   
         [0074]    [0074] 111  Channel, connecting cavities  19  and  28   
         [0075]    [0075] 113  Channel, connecting cavities  25  and  28   
         [0076]    [0076] 114  Channel, connecting cavities  25  and  26   
         [0077]    [0077] 115  Channel, connecting cavities  26  and  27   
         [0078]    [0078] 116  Channel, connecting cavities  27  and  28   
       DETAILED DESCRIPTION OF THE INVENTION  
       [0079]    Present invention is applicable to the following three types of TSICE:  
         [0080]    1) spark ignited (e. g. gasoline, propane) engine with an external mixing of air and fuel in the intake manifold and use of air-fuel mixture for scavenging of power cylinders;  
         [0081]    2) spark ignited (e.g. gasoline) engine with scavenging of power cylinders with pure air and direct fuel injection into the power cylinders at the beginning of compression stroke after their ports are already closed;  
         [0082]    3) self-ignited (diesel) engine with scavenging of power cylinders with pure air and direct fuel injection into the power cylinders at the end of compression stroke.  
         [0083]    In TSICE of second and third types cylinders are scavenged/charged with pure air, having fuel injected directly into the cavity of power cylinder. In these engines low-pressure fuel injector  101  in the engine intake manifold is not present. Instead, in the second type of spark-ignited engine low-pressure direct fuel injector  99  installed in the power cylinder is used together with a spark plug  79 . In self-ignited TSICE of the third type spark plug  79  is replaced with a high-pressure direct fuel injector  80 . The direct injection of fuel into the power cylinders after scavenging is complete and ports of the power cylinders are closed, eliminates fuel loss and mixing of a fresh charge with burned gases.  
         [0084]    Drawings and descriptions are made as for the first type of TSICE.  
         [0085]    TSICE, shown on FIG. 13, is a single-row double-bank engine with two pistons  9  and  13 , connected to each other with the piston rod  74 , connected to the crank  70  by the connecting rod  76  and reciprocally movable in the cylinders  1  and  5 , separated by the transverse partition  69 . The cylinder  5  is double-sided whose power cavity  25  and pumping cavity  26  are connected to the power cavity  17  of cylinder  1  respectively by the channels  103  and  104 . The channel  103  represents a common combustion chamber for the cavities  17  and  25 , where air-fuel mixture is ignited by the spark plug  79 . Since one pumping cavity is used for the charging of two power cavities, the intake port  42  of the pumping cavity  26  is connected to the external supercharger.  
         [0086]    The method of operation of the TSICE on FIG. 13 is as follows.  
         [0087]    At the end of power stroke, as it is shown on FIG. 13, both pistons  9  and  13  are at BDC. Fresh portion of air-fuel mixture, compressed in the cavity  26  during the power stroke, enters the cavity  17  through the open intake port  33 , providing direct-flow scavenging/charging of cavities  17  and  25  through the channel  103 , with the escape of burned gases through the exhaust port  57 . The pistons  9  and  13 , moving towards TDC, compress air-fuel mixture in the cavities  17  and  25  and at the same time create a vacuum in the cavity  26 . When the pistons reach TDC, the intake port  42  opens and cavity  26  is charged with another fresh portion of air-fuel mixture by joint action of the supercharger  91  and the inside vacuum. At the same time, the ignition of compressed air-fuel mixture in the cavities  17  and  25  starts a power stroke, when the pistons go down until they reach BDC, and the process continues, as described above.  
         [0088]    [0088]FIGS. 15A and 15B is a double-row double-bank TSICE with double-sided cylinders in the second bank. The pistons  9  and  13 , reciprocally movable in the cylinders  1  and  5 , are connected to the crank  70 . The pistons  10  and  14 , reciprocally movable in the cylinders  2  and  6 , are connected to the crank  71 . The cranks  70  and  71  have 180° angular deviation from each other, enabling motion of the pistons of the first and second rows in phase opposition. The cavities  19  and  26  are power cavities, connected to each other by the channel  109 , shown on FIG. 15A and representing their common combustion chamber. The cavities  19  and  26  have the common spark plug  79 , common intake port  42 , located in the cavity  26 , and the common exhaust port  51 , located in the cavity  19 . The cavities  17  and  28  are also power cavities, connected to each other by the channel  105 , shown on FIG. 15B and representing their common combustion chamber. The cavities  17  and  28  have the common spark plug  79 , common intake port  44 , located in the cavity  28 , and the common exhaust port  49 , located in the cavity  17 . The cavities  25  and  27  are pumping cavities. They have individual intake ports  41  and  43  and exhaust ports  57  and  59 , connected to the intake ports  42  and  44  of power cavities by the channels  114  and  116 . Since two pumping cavities are used for charging of four power cavities, the supercharger  91  is connected to the intake ports  41  and  43  of pumping cavities through self-acting suction valves  98 .  
         [0089]    The method of operation of the TSICE on FIGS. 15A and 15B is as follows. At the end of a power stroke, as it is shown on FIG. 15A, the pistons  9  and  13  are at TDC and the pistons  10  and  14  are at BDC. The pumping cavity  27  is charged with fresh portion of air-fuel mixture. The intake port  42  and the exhaust port  51  are open, and direct-flow scavenging/charging of the power cavities  26  and  19  goes on. Compressed in the pumping cavity  25  air-fuel mixture is released through the channel  114  into the cavity  26  and from there through the channel  109  into the cavity  19 , pushing the rest of the burned gases out of the exhaust port  51 . At the same time, the ignition of air-fuel mixture, compressed in the power cavities  17  and  28 , initiates in them a power stroke, moving the pistons of the first and second row towards each other. The process of scavenging/charging of the cavities  19  and  26  ends, when the ports  42  and  51  close. With further move of the pistons  9  and  13  towards BDC and the pistons  10  and  14  towards TDC, the air-fuel mixture is compressed in the cavities  19  and  26 , another portion of air-fuel mixture is compressed in the pumping cavity  27 , and the pumping cavity  25  is filled with yet another portion of pressurized air-fuel mixture through the valve  98  and the intake port  41 . When the pistons  9  and  13  reach BDC and the pistons  10  and  14  simultaneously reach TDC, as shown on FIG. 15B, the intake port  44  and the exhaust port  49  open and scavenging/charging of the power cavities  28  and  17  takes place. Compressed in the pumping cavity  27  air-fuel mixture is released through the channel  116  into the cavity  28  and from there, through the channel  105  into the cavity  17 , pushing the rest of the burned gases out of the exhaust port  49 . At the same time, the ignition of air-fuel mixture, compressed in the power cavities  19  and  26 , initiates in them a power stroke, moving the pistons of the first and second row towards each other. The process of scavenging/charging of the cavities  17  and  28  ends, when the ports  44  and  49  close. With further move of the pistons  9  and  13  towards TDC and the pistons  10  and  14  towards BDC, air-fuel mixture is compressed in the cavities  17  and  28 , another portion of air-fuel mixture is compressed in the pumping cavity  25 , and the cavity  27  is filled up with yet another portion of pressurized air-fuel mixture through the valve  98  and the intake port  43 . After pistons of the first and second rows reach respectively TDC and BDC, the process continues, as described above.  
         [0090]    An advantage of this version of the TSICE is that the phase opposition of the cranks  70  and  71  balances the forces applied to the crankshaft bearings and reduces counterweights and inertial masses of the engine.  
         [0091]    TSICE, shown on FIGS. 16A and 16B, as the previous version of TSICE, also has pistons of the first and second rows in phase opposition, with the difference in location of power and pumping cavities and connecting channels. It has the same method of operation, providing, that the cavities  25  . . .  28  are power cavities and the cavities  17  and  19  are pumping cavities.  
         [0092]    The pistons  9  and  13 , reciprocally movable in the cylinders  1  and  5 , are connected to the crank  70 . The pistons  10  and  14 , reciprocally movable in the cylinders  2  and  6 , are connected to the crank  71 . The cranks  70  and  71  have 180° angular deviation from each other, enabling motion of the pistons of the first and second rows in phase opposition. The cavities  26  and  27  are power cavities, connected to each other by the channel  115 , shown on FIG. 16A and representing their common combustion chamber. The cavities  26  and  27  have the common spark plug  79 , common intake port  42 , located in the cavity  26 , and the common exhaust port  59 , located in the cavity  27 . The cavities  25  and  28  are also power cavities, connected to each other by the channel  113 , shown on FIG. 16B and representing their common combustion chamber. The cavities  25  and  28  have the common spark plug  79 , common intake port  44 , located in the cavity  28 , and the common exhaust port  57 , located in the cavity  25 . The cavities  17  and  19  are pumping cavities. They have individual intake ports  33  and  35  and exhaust ports  49  and  51 , connected to the intake ports  42  and  44  of power cavities by the channels  104  and  111 . Since two pumping cavities are used for charging of four power cavities, the intake ports  33  and  35  of pumping cavities are connected to a supercharger (not shown on FIG. 16).  
         [0093]    The method of operation of the TSICE on FIGS. 16A and 16B is as follows. At the end of a power stroke, as it is shown on FIG. 15A, the pistons  9  and  13  are at TDC and the pistons  10  and  14  are at BDC. The pumping cavity  19  is charged with fresh portion of air-fuel mixture. The intake port  42  and the exhaust port  59  are open, and direct-flow scavenging/charging of the power cavities  26  and  27  goes on. Compressed in the pumping cavity  17  air-fuel mixture is released through the channel  104  into the cavity  26  and from there through the channel  115  into the cavity  27 , pushing the rest of the burned gases out of the exhaust port  59 . At the same time, the ignition of air-fuel mixture, compressed in the power cavities  25  and  28 , initiates in them a power stroke, moving the pistons of the first and second row towards each other. The process of scavenging/charging of the cavities  26  and  27  ends, when the ports  42  and  59  close. With further move of the pistons  9  and  13  towards BDC and the pistons  10  and  14  towards TDC, the air-fuel mixture is compressed in the cavities  26  and  27 , another portion of air-fuel mixture is compressed in the pumping cavity  19 , and the pumping cavity  17  is filled with yet another portion of pressurized air-fuel mixture through the intake port  33 . When the pistons  9  and  13  reach BDC and the pistons  10  and  14  simultaneously reach TDC, as shown on FIG. 16B, the intake port  44  and the exhaust port  57  open and scavenging/charging of the power cavities  28  and  25  takes place. Compressed in the pumping cavity  19  air-fuel mixture is released through the channel  111  into the cavity  28  and from there, through the channel  113  into the cavity  25 , pushing the rest of the burned gases out of the exhaust port  57 . At the same time, the ignition of air-fuel mixture, compressed in the power cavities  26  and  27 , initiates in them a power stroke, moving the pistons of the first and second row towards each other. The process of scavenging/charging of the cavities  25  and  28  ends, when the ports  44  and  57  close. With further move of the pistons  9  and  13  towards TDC and the pistons  10  and  14  towards BDC, air-fuel mixture is compressed in the cavities  25  and  28 , another portion of air-fuel mixture is compressed in the pumping cavity  17 , and the cavity  19  is filled up with new portion of pressurized air-fuel mixture through the intake port  35 . After pistons of the first and second rows reach respectively TDC and BDC (FIG. 16A), the process continues, as described above.  
         [0094]    In comparison with the previous version of TSICE, shown on FIG. 15, engine on FIG. 16 has more preferable location of spark plugs and has no need in self-acting suction valves. Together those versions show the available variety of structural options.  
         [0095]    All the engines, described above, achieve the object of increasing of power per liter of displacement.  
         [0096]    The few shown examples of present invention can be used in a wide variety of applications, from small appliances, to the huge diesel marine engines.  
         [0097]    Many more modifications of the present invention are possible, and among those, described above, TSICE, presented on FIG. 16, is considered as the preferred embodiment. Nevertheless, other shown embodiments may be given preference in different applications.  
         [0098]    The scope of the invention should be determined by the appended claims, rather than by the examples given.