FIELD OF THE INVENTION 
     This invention relates to internal combustion engines and more particularly to internal combustion engines and methods of operating the engines with a new fuel saving cycle 
     BACKGROUND OF THE INVENTION 
     The present economic condition is particularly bad with respect to gasoline and diesel fuel for cars and heavy trucks. While efforts are being made to provide hybrid automobiles that can operate on rechargeable batteries at least part of the time, nevertheless most still have engines as well that must rely upon gasoline or diesel fuel. The need to make engines more efficient still exists particularly because of rising gasoline and diesel fuel costs. 
     BRIEF DESCRIPTION OF THE INVENTION 
     It is an object of the present invention to provide an internal combustion engine which achieves a measure of fulfillment of the need for more efficient and fuel saving engines. 
     In accordance with the principles of this inventions this objective is achieved by providing an engine which includes at least two piston and cylinder assembles preferably adjacent to one another, at least one of which includes a fuel injector and both of which are connected to a crank shaft so that the pistons of both assemblies move simultaneously through repetitive cycles each, including simultaneous compression strokes and immediately following simultaneous power drive strokes. The two assemblies, when operating with the new fuel savings cycle, establish at the end of the simultaneous compression strokes a charge of compressed air in one cylinder of one of the assemblies and a charge of compressed air fuel mixture in the other cylinder of the other assembly. When the air fuel mixture is ignited, the high pressure conditions in the other cylinder are immediately communicated through a passage to the one cylinder to accomplish a double expansion during the simultaneous power drive strokes thus using much of the pressure energy before exhaust occurs by the pistons themselves rather than to dump it as is usually done. 
     Preferably, the engine includes a second fuel injector which is controlled selectively with respect to the first fuel injector to operate in accordance with a normal mode where both assemblies are simultaneously operated alike in which case both cylinders establish a charge of compressed air-fuel mixture at the ends of the simultaneous compression strokes so that in effect a double charge can be ignited to act on both pistons simultaneously. 
     The invention can be embodied in engines in which the injections made by the injectors cause the ignition (as in conventional compression ignition) or in which the injections are made during simultaneously intake strokes and ignition is made by a spark ignition system. In the case of spark ignition, under normal mode operation the ignition of the second air fuel charge is ignited by a high pressure flame resulting from the ignition in the first cylinder extending through the passage. 
     The engines embodying the principles of the present invention can be operated either on a four cycle basis or a two cycle basis. 
     The invention is most easily applicable to engines of the opposed piston type. A particularly efficient embodiment utilizes the opposed pistons in one cylinder type of setup utilized in the new Eco Motors (located in Allen Park, Mich.) engine. The Eco Motors set up includes two cylinders disposed on opposite sides of a central portion of the crankshaft. The central portion of the crankshift is connected to a pair of connecting rods so as to move a pair of pistons one within each cylinder in two stroke cycles out of phase 180° with respect to one another. An opposing piston is mounted in the cylinders, each of which is constrained to move in a cooperating two stroke cycle by a pair of parallel elongated connecting rods pivoted to an opposing piston and to the crankshaft so as to be 180° out of phase with respect to one another. 
     The Eco Motors engine is advertised as being modular. A dual modular engine includes two modular engines connected together by a clutch assembly. The dual modular engine is comparable to the eight cylinder engines capable of operating on four cylinders only to save fuel. Thus, instead of four non-fueled piston and cylinder assemblies simply going through the motions, the clutch makes it possible to render one modular engine totally inoperable. 
     One of the objects of the present invention is to reconfigure the Eco Motors dual modular with clutch engine (or another similar such engine) and achieve selective normal operation and fuel saving operation in an improved new cycle way so that the reconfiguration saves parts and the new cycle is more efficient when compared with the dual modular Eco Motors engine and its operation in fuel saving mode. 
     In accordance with the principles of the present invention the above objective is achieved by abandoning the modular idea and mounting two side by side cylinders on opposite sides of a single central crank shaft so that in each pair of cylinders a pair of opposed pistons move simultaneously through the same two stroke cycle. In this way the events occurring in each pair of side by side cylinders are the same but 180° out of phase with one another. The fuel saving mode is accomplished simply by providing a passage between each pair of side by side cylinders at the central combustion chamber areas, and then reprogramming the computer operated fuel injectors so that one of the two injectors for the two cylinders does not inject instead of both injecting as in normal operation. Consequently, in fuel saving mode the one cylinder which receives an injection when ignited will immediately communicate the resulting high pressure conditions through the passage to the other cylinder to raise the charge of air therein at compression pressure. With the pressure created by the one ignition acting on two pistons to effect simultaneous power drive strokes of two pistons a double working pressure expansion occurs, thus utilizing much of the pressure energy that usually is dumped to exhaust. 
     Others objects, features and advantages of the present disclosure will become apparent from the following detailed description, the accompanying drawings, and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a horizontal sectional view of an internal combustion engine embodying the principles of the present invention; 
         FIG. 2  is a section view taken alone the line  2 - 2  of  FIG. 1 ; 
         FIG. 3  is a schematic view showing a pressurized air intake system; 
         FIG. 4  is a schematic view showing a computer controlled fuel injection system; 
         FIG. 5  is a top plan view of another engine embodying the principles of the present invention with parts broken away and shown in horizontal section for purposes of clearer illustration; 
         FIG. 6  is an enlarged horizontal sectional view of one end portion of the engine of  FIG. 5  showing the position of the parts in mid stroke; 
         FIG. 7  is a view similar to  FIG. 6  showing the position of the parts after a 180° turn of the output shaft from the position show in  FIG. 6  shaft; 
         FIG. 8  is a view similar to  FIG. 5  showing the position of the parts after another 180° turn of the output shaft from the position shown in  FIG. 7 ; 
         FIG. 9  is a view similar to  FIG. 5  showing the position of the parts after another 180° turn of the output shaft from the position shown in  FIG. 8 ; and 
         FIG. 10  is a horizontal sectional view of a spark ignited engine embodying the principles of the present invention which operates on a two stroke cycle. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring more particularly to the drawings, there is shown in  FIGS. 1 and 2  there of an internal combustion engine, generally indicated at  10 , that embodies the principles of the present invention. 
     The engine  10  includes a main frame structure  12  shown illustratively as one piece in the drawings. In actuality, the frame may be made up of many conventional pieces. In the illustrative one piece embodiment shown the frame structure defines pairs of side by side cylinders  14 L and  14 R disposed in general alignment on opposite sides of an output crank shaft  16 . Mounted within the pairs of cylinders  14 L and  14 R are pairs of opposed pistons  18 L and  20 L and  18 R and  20 R respectively. 
     The pair of pistons  18 L are slidably sealingly mounted in the pair of cylinders  14 L for simultaneous movements together toward and away from the crank shaft  16  by a pair of connecting rods  22 L pivotally connected at one of their ends to the pair of pistons  18 L (as by wrist pins not shown) with their opposite ends rotatably mounted on two aligned interior cranks  24  of the crank shaft  16 . 
     The pair of pistons  18 R are slidably sealingly mounted in the pair of cylinders  14  R for simultaneous movements together toward and away from the crank shaft  16  by a pair of connecting rods  22 R pivotally connected at one of their ends to the pair of pistons  18 R (as by wrist pins not shown) with their opposite forked ends rotatably mounted on the two interior cranks  24 . 
     The pair of pistons  20 L are slidably sealingly mounted in the pair of side by side cylinders  14 L outwardly of the pair of pistons  18 L therein for simultaneous movements toward the pistons  18 L as the pistons  18 L move away from the crankshaft  16  and away from the pistons  18 L as the pistons  18 L move toward the crank shaft  16 . 
     The simultaneous movements of the pair of pistons  20 L is accomplished by a pair of fixed rods  26 L extending outwardly of the pair of pistons  20 L and having a shaft  28 L extending transversely therethrough so as to be relatively pivoted with respect to the piston rods  26 L about the axis of the shaft  28 L. The shaft  28 L moves within three axially spaced slots  30 L formed in the adjacent end of the frame structure  12  as shown, the central portion of the shaft  28 L extending between the spaced connecting rods  26 L slides in the central slot  30 L and opposite ends of the shaft  29 L extend outwardly of the rods  26 L through the outer two slots  30 L and then beyond the adjacent frame structure  12 . 
     Pivoted to the outwardly extending ends of the shaft  28 L are one of the ends of a pair of exterior connecting rod&#39;s  32 L. The pair of exterior connecting rods  32 L extend inwardly toward the crank shaft  16  and have their inner ends rotatably connected to two exterior cranks  34  on the opposite ends of the crank shaft  16  transversely outwardly of the adjacent frame structure  12 . 
     The pair of outer pistons  20 R are related to the pair of inner pistons  18 R and move simultaneously together and away from one another by a similar assembly of components including piston rods  26 R, shaft  28 R moving in slots  30 R and a pair of exterior connecting rods  32 R having their inner ends rotatably connected to the cranks  34  of the crank shaft  16  and their outer ends pivotally connected with outer ends of the shaft  28 R. 
     It can be seen from the connection of the connecting rods  22 L and  22 R, between the crank shaft  16  and inner pairs of pistons  18 L and  18 R and the connection of the exterior connecting rods  32 L and  32 R between the crank shaft  16  and the outer pairs of pistons  20 L and  20 R, the pairs of pistons  18 L and  20 L move simultaneously trough two stroke repetitive cycles each including (1) a compression stroke wherein the pairs of pistons  18 L and  20 L move from an outer limiting position spaced widely apart toward one another into inner limiting position spaced apart but almost together and (2) a power drive stroke wherein the pairs of pistons  18 L and  20 L move from the inner limiting position to the outer limiting position away from one another. 
     The pairs of pistons  18 R and  20 R have a similar two stroke repetitive cycle. However, since they are connected to the same cranks of the crank shaft  16  (i.e., at the same crank axis), the two stroke cycle thereof is displaced 180° from the two stroke cycle of the pairs of pistons  18 L and  20 L. Stated differently, the pistons  18 L and  20 L move through a compression stroke while the pistons  18 R and  20 R move through a power drive stroke and when the pistons  18 L and  20 L move through a power drive stroke the pistons  18 R and  20 R move through a compression stroke. 
     The pistons  18 L- 20 L and  18 R- 20 R are moved through repetitive out of phase two stroke cycles during each revolution of the crankshaft  16  because during the time when the pistons are near the outer limiting positions a flow of air under pressure is made to pass into one end of each pair of side by side cylinders  14 L or  14 R through an inlet opening  36  in each cylinder  14  and out an outlet opening  38  at the opposite end of each cylinder. Conversely, the pistons in the other cylinders are in the inner limiting position and the openings  36 ,  36  are closed off. 
       FIG. 3  illustrates schematically how a pump  41  (suitable to be driven by the output shaft  16 ) feeds a pressurized flow of air through tubes to each inlet opening  36  when the inlet openings and outlet openings  38  are opened in accordance with known practice by the movement of the associated pistons  18  or  20  thereby near the end of the power drive strokes thereof. 
     As the pistons  18  and  20  move through the initial portion of their compression stroke, the pressurized air that has moved into the cylinders  14  is trapped therein because the pistons move past the openings  36  and  38  in the opposite direction to close them. The trapped air is then pressurized as pistons  18  and  20  move together in their compression stroke. 
     In the embodiment shown, the compression ratio is chosen so that when the pistons  18  and  20  reach near or at their inner limiting positions, the pressure and temperature conditions of the air is such that an injection of fuel also causes compression ignition to occur. 
     As shown in the drawings, there is a fuel injector  42  carried by the frame structure  12  in association with each cylinders  14  is positions so that its nozzle enters within the cylinder  14  in the combustion chamber space between the pistons  18  and  20  when in their inner limiting positions. 
       FIG. 4  illustrates schematically the four fuel injectors  42  having high pressure fuel lines  44  leading thereto from a conventional source, indicated schematically by the numeral  46 . The fuel injectors  42  are constructed and arranged with electrically operated valves shown schematically at  48  which open to inject fuel into the cylinder  14  and close to stop injection. Electrical lines  50  are shown schematically connected to the valves  48 . The lines  50  are shown connected to a computer, shown schematically by the numeral  52 . The lines  50  transmit signals to the valves  48  to open and close them with the interval between the opening signal and the closing signal determining the amount of fuel injected. 
     Also, each pair of side by side cylinders  14  are made to communicate with one another by a passage  54  extending between each side by side pair at central portions thereof opposite the injectors  42 . The computer  52  is programmed to selectively cause one injector  42  associated with one cylinder of each pair of side by side cylinders  14  to inject zero fuel or in other words not to inject. 
     The computer  52  normally operates the four injectors  42  to inject the same amount of fuel into both of each same-side pair of cylinders  14 L or  14 R to cause ignition to occur therein bearing in mind that the injection in the one pair of cylinders  14 L or  14 R is 180° out of phase with other pair of cylinders  14 L or  14 R. It will be noted that simultaneous ignition occurs in both cylinders of a pair so that passage  54  is not significantly in play as the high pressure created by ignition in both cylinders  14  will act on both pairs of opposed pistons  18  and  20 . 
     When the computer  52  signals one of the two injectors  42  of each same-side pair of cylinders  14  not to inject, the ignition of the fuel in the other that receives fuel causes high pressure to rise in that cylinder  14 , which high pressure is immediately communicated by the passage  54  to the other cylinder  14  at the lower compression pressure so that both pairs of opposed pistons  18  and  20  are moved through power drives strokes together. In effect, the single ignition results in double working expansion of the pressure energy created. 
     This fuel saving mode of operation which can be selected by the computer  52  reduces the fuel used by the engine in half just as is done with the V-8 that can selectively operate on four cylinders or the dual modular Eco Motor with clutch. The fuel saving mode of the present invention operates all moving components of the engine with a more efficient use of the lesser fueled ignitions. 
     In order for the computer  52  to select the fuel saving mode in automobile usage, the function of the automobile must be electrically sensed and transmitted to the computer  52 . Known sensors exist in automobiles equipped with the V-8 Engine that operates fuel savings with four cylinders. For example, normal operation is selected when the gas pedal movement to accelerate the car is sensed and fuel saving mode is selected when brake pedal movement is sensed. Cruise control when sensed to be on could be used to select fuel saving mode. Sensing motor rotation without wheels turning (idling) would select fuel saving mode. 
     Referring again more particularly to the drawings there is shown in  FIGS. 5-9  thereof a spark ignite internal combustion engine, generally indicated at  110 , embodying the principles of the present invention. The engine  110  includes a frame structure, generally indicated at  112 , which is shown, in  FIG. 5  as being of three piece construction including a main body structure  114  with a head structure  116  on opposite ends of the main body structure  114 . It will be understood that the three piece construction is illustrative only and that the frame structure  114  would be actually constructed in many pieces in accordance with known practice. 
     As shown in  FIG. 5 , the engine  110  is opposed piston configuration having opposed duplicate operative piston and cylinder assemblies connected to opposite sides of a centrally located output crankshaft  124  so that the assembles are 180° out of phase with respect to one another. 
     Since the piston and cylinder assemblies are duplicates of one another, a description of one will suffice to give an understanding of both, keeping in mind that they are 180° out of phase with respect to one another. 
     Referring now more particularly to the drawings there thereof as best shown in  FIGS. 5-8 , the body structure  114  includes structures defining four inline cylinders, designated by the numeral  118  with added letters A through D respectively. Slidably sealingly mounted in the four cylinders  118  are four pistons, designated by the numeral  120  with added letters A through D respectively. 
     Each piston  120  has one end of a connecting rod  122  pivotally connected thereto as by a conventional wrist pin (not shown). The opposite end of each connecting rod  122  is rotatably connected to the output shaft  124 . The output shaft  124  is formed with four U-shaped crank portions, designated by the numeral  126  with added letters A through D respectively, spaced apart by straight bearing portions  128  journalled in bearings suitably mounted on the body structure  114 . The crank portions  126 A and  126 D are oriented to extend outwardly from the adjacent bearing portions  128  in the same directions and the crank portions  126 B and  126 C are oriented to extend outwardly from the adjacent bearing portions  128  in the same direction but disposed 180° from the direction of extent of the crank portions  128 . 
     Each connection between the ends of the piston rods  122  with the output crank shaft  124  is accomplished by journaling an end of a respective piston rod  122  rotationally on the right of a respective U-shaped crank portion  126 . As a result of the orientation of the crank portions  126  and the connection of the piston rods  122  rotatably connected thereto and to the pistons  120  for pivotal movement, the pistons  120 A and  122 D will move together through simultaneous strokes in one direction while the pistons  120 B and  120 C move together through simultaneous strokes in an opposite direction. 
     The head structure  116  which defines an end wall closure for all four cylinders  118  has formed therein an air supply passage designated by the numeral  132  with added letters A through D respectively which communicates with the four cylinders  118  through four inwardly facing valve seat defining inlet openings designated by the numeral  134  with added letters A through D respectively. The head structure  116  also has formed therein four exhaust passages designated by the numeral  136  with added letters A through D respectively which communicate with the four cylinders  118  through four inwardly facing valve seat defining outlet openings, designated by the numeral  138  with added letters A through D respectively. 
     Mounted on the head structure  116  for movements toward the inlet openings  134  into sealing relation thereto and away from the inlet openings  134  into opening relation thereto are four stem operated poppet valves, designated by the numeral  140  with added letters A through D respectively. Also mounted on the head structure  116  for movements toward the outlet openings  138  into sealing relation thereto and away from the outlet openings  138  into opening relation thereto are four stem operated poppet valves, designated by the numeral  142  with added letters A through D respectively. 
     The poppet valves  140  and  142  are spring biased to move into sealing relation with their associated openings  134  and  138  by conventional springs  139  and are moved against the spring bias into opening relation to their associated openings  134  and  138  by a camshaft  144  rotatably mounted on the head structure  116  in a position overlying the valves  140  and  142  and the openings  134  and  138 . The camshaft  144  is rotationally moved at a rotational speed one half the rotational speed of the output shaft  124  by a conventional rotational movement transmitting mechanism  145  connected between the output shaft  124  and the camshaft  144  so that during every two revolutions of the output shaft  124  the camshaft  144  is driven thereby through one revolution. In this way, the camshaft  144  is able to move the valves  140  and  142  through one cycle of movement while the pistons  120  are moving through a four consecutive 180° strokes of movement. 
     The sequence of the cycle of movements of the valves  140  and  142  is determined by four inlet opening and closing cam portions, designated by the numeral  146  with added letter A through D respectively. 
     Formed on the camshaft  144  in axially spaced relation in alignment with and to engage the stem end of the four inlet valves  140  are four outlet opening and closing cam portions, designated by the numeral  148  with added letters A through D respectively. The cam portions  148  are formed on the camshaft  144  in axially spaced relation in alignment with and to engage the stem ends of the four outlet valves  142 . Each cam portion  146  and  148  is configured to provide (1) leading surfaces which when engaged with a valve stem moves the valve  142  or  144  in opening relation to the associated opening, (2) a trailing surface which when engaged with a valve stem moves the valve  140  or  142  into sealing relation to the associated opening and (3) a central surface between the leading and trailing surfaces which when engaged with a valve stem holds the valve  140  or  142  in opening relation to the associated opening. The four stroke cycle of movement of each piston  120  controlled by the rotation of the output shaft  124  through two revolutions are as shown in  FIGS. 6-9  and identified in order as an intake stroke, a compression stroke, a power drive stroke, and an exhaust stroke. The coordinated movements of each inlet valve  140  and outlet valve  142  during the four identified piston strokes of the associated piston  120  is as follows (1) during the intake stroke inlet valve  140  is opened and outlet valve  142  is closed (2) during the compression and power drive strokes both valves  140  and  142  are closed and during the exhaust stroke inlet valve  140  is closed and outlet valve  142  is opened. The exact timing of the required valve movement within the associated strokes is in accordance with known practice. 
     It will be understood that the four supply passages  132  are communicated with a source of filtered air similar to that shown in  FIG. 3  and the four exhaust passage  136  are communicated with a muffled exhaust manifold (not shown). 
     The engine  110  also includes four fuel injectors, designated generally by the numeral  150  with added letters A through D respectively. The four fuel injectors  150  are of known construction and embody a known control system similar to the one shown in  FIG. 4  an example, is embodied in a 4 cylinder, four cycle GM engine. Each injector  150  is communicated with a pressurized fuel containing manifold (not shown) through a opening in an upper end  152  thereof. Each upper open end  152  communicates the fuel under pressure received therein to a lower discharge nozzle  154 . Each injector  150  also includes an electrically controlled valve similar to the valves between the upper ends  152  of  FIG. 4  and lower nozzle  154 , which allows fuel under pressure to flow from the nozzle  154 , when open, and to prevent the flow of fuel under pressure from the nozzle  154  when closed. The timing between the opening of the control valve and the closing of the control valve determines the amount of fuel injected. The electrically operated control valves are operated by electrical signals from a computer similar to the computer  52  shown in  FIG. 4 . 
     In accordance with the principles of the present invention, the frame structure  116  has a passage  156  formed therein that communicates cylinder  118 B to cylinder  118 C (the two middle cylinders) adjacent the valve ends thereof. 
     A conventional distributor—spark plug ignition system is provided for the engine  110 , the distributor components of which also not shown, the ignition system includes a spark plug  162  associated with cylinder  118 B and spark plugs  164 A and  164 D associated with cylinders  18 A and  18 D. 
     In the normal operation of the engine  110 , the pistons  120 A and  120 D in cylinders  118 A and  118 D have simultaneous intake strokes during which the injectors  150 A and  150 D inject the same amount of fuel into the air being drawn into the respective cylinder  118 A or  118 D. The charges of air fuel mixture within the cylinders  118 A and  118 D established at the end of the simultaneous intake strokes of pistons  120 A and  120 D therein are compressed during the following simultaneous compression stroke of the pistons  120 A and  120 D into compressed charges of mixed fuel and air. When the spark plugs  164 A and  164 D are simultaneously activated, the pistons  120 A and  120 D will be moved through their simultaneous power drive strokes, followed by simultaneous exhaust strokes. 
     In normal operation, the injectors  150 B and  150 C in cylinders  118 B and  118 C are also injected with the same amount of fuel as cylinders  118 A and  118 D. When pistons  120 B and  120 C establish charges of compressed air and fuel mixture therein at the end of the simultaneous compression strokes thereof, the charges of compressed air and fuel mixture in cylinders  118 B is ignited by spark plug  162  and the resulting ignition creates a pressurized flame in cylinder  118 B which passes through passage  156  into cylinder  118 C to ignite the charge of compressed air and fuel mixture in cylinder  118 C. 
     In accordance with the principles of the present invention, during the fuel saving cycle of a fuel saving mode, the injector  150 C associated the cylinder  118 C does not go through an injection cycle but injector  150 B does. Thus, when the pistons  120 B and  120 C reach the end of their simultaneous compression strokes, cylinder  118 B will have established therein a charge of compressed air and fuel mixture while cylinder  118 C will have established therein a charge of compressed air. 
     When the charge of compressed air and fuel mixture in cylinder  118 B is ignited by spark plug  164 B, the high pressure conditions created as a result thereof are immediately communicated by means of passage  156  with the charge of compressed air in cylinder  118 C to raise the pressure acting on pistons  120 C during the simultaneous power drive stroke thereof with piston  120 B. 
     Since the pistons  120 A and  120 D together are 180° out of phase with the pistons  120 B and  120 C together. The simultaneous power drive strokes of both pairs will fall within one rotation of the output shaft  124 . It will be remembered that the opposite duplicate bank is also 180° out of phase with the first bank so that the simultaneous power drive strokes of both duplicate pairs in the duplicate bank will occur within the other full rotation of the out put shaft  124  in each two rotational cycle. Thus, a pair of simultaneous power drive strokes will be applied to the shaft  124  during each half revolution thereof. In normal mode operation all of the power drive strokes will be of the same force. During the fuel saving mode of operation, the outer pair of pistons in each bank have equal power drive strokes equal to those of normal operation. However, the power drive stroke of the inner pair of each bank are powered by one half the fuel and go through twice the expansion. 
     It should be noted that with spark ignition in normal mode operation, the time delay between the ignition in the first cylinder and the time the ignition of the first takes to ignite the second could move peak pressures in the second nearer the most efficient crank angle. 
     It is also within the contemplation of the present invention to provide either a one bank or two bank internal combustion engine which operates at all items within the gas saving cycle of the present invention. 
     Referring now to  FIG. 10  there is shown therein an engine  210  embodying the principles of the present invention which operates on a two stroke cycle rather than on a four stroke cycle. As shown similar parts have been given numbers with a leading  2  rather than the leading  1  as in  FIGS. 5-9  so that the description will be concerned only with the differences. 
     First, the exhaust outlets  136  are changed to inlets designed by the numeral  282  with added letters A through D respectively. Thus outlet valves  142  A-D become inlet valves  254 A-D that are moved simultaneously with the inlet valves  240  A-D respectively. 
     Second, the cylinders  220  are formed with a series of annularly spaced outlets, designated by the numeral  286  with added letters A through D respectively, as before, the inlets  232  and  282  communicate with a filtered air manifold (source not shown) and the outlets  286  communicate with a muffled exhaust manifold not shown. 
     The four piston and cylinder assemblies of the engine  210  are provided with a different cam shaft  288  for controlling each assembly to go through a two stroke cycle of movement during each revolution of output shaft  224 . The rotational motion transmission assembly  145  is changed to effect this change as indicated at  290  so that the rotation of the cam shaft  288  is driven through one revolution during each rotation of the output shaft  224 . Each cycle includes a gaseous charge exchange portion which establishes that each piston has an appropriate charge of compressed gas therein either an air-fuel mixture or air without fuel mixed therein at the end of a first compression stroke. The charges of compressed air-fuel mixture are then ignited to begin a return power drive stroke at the end of which the gaseous charge exchange portion begins when the associated piston  220  moves below the outlets  286  and inlet valves  243  and  284  are opened. The gaseous charge exchange portion ends with the movement of the piston  220  upwardly beyond the outlets  286  after which the rest of the stroke is compression. 
     The crank shaft  224  is the same as far as piston movements are concerned. The piston  220 B and  220 C move together while pistons  220 A and  220 D move together. With the cycle the same and thereof 180° out of phase with respect to simultaneous cycles of pistons  220 B and  220 C. 
       FIG. 10  shows the position of the parts with the pistons at respective mid positions of movement corresponding to the middle of the power drive strokes of pistons  220 B and  220 C and the middle of the compressing strokes of piston  220 A and  220 D, with all valves closed. When the engine  210  with spark ignition is in a fuel saving mode, the two middle piston and cylinder assemblies B and C go through a gas exchange portion together but only cylinder  218 B receives a fuel charge during gas exchange so that at the end of the compression stroke cylinder  218 B has a charge of compressed air-fuel mixture therein while cylinder  218 C has a charge of compressed air therein. As before the ignition of the charge in cylinder  218 B is communicated through passage  256  to raise the air compression pressure in cylinder  218 C and effect the power drive stroke thereof together with the drive stroke of piston  220 B. 
     The same cycle is carried out in cylinders  220 A and  220 D only 180° out of phase with respect to one another. The operation in normal mode operation is that both cylinders receive a charge of air-fuel mixture which are both ignited as before. The engine  210  has the advantage that a double power drive stroke is applied every half turn of the output shaft  224 . The fuel saving mode achieves the advantage previously noted. 
     The foregoing illustrated embodiments have been provided solely to illustrate the structural and functional principles of the present invention, and are not intended to be limiting. 
     To the contrary, the present invention encompasses all modifications, alterations, substitutions, and equivalents within the spirit and scope of the appended claims.
This invention relates to internal combustion engines and more particularly to internal combustion engines and methods of operating the engines with a new fuel saving cycle. An engine including at least two piston and cylinder assemblies preferably adjacent to one another, that when operating with the new fuel savings cycle, establish at the end of the simultaneous compression strokes a charge of compressed air in one cylinder of one assembly and a charge of compressed air fuel mixture in the other cylinder of the other assembly. When the air fuel mixture is ignited, the high pressure conditions in the other cylinder are immediately communicated through a passage to the one cylinder to accomplish a double expansion during the simultaneous power drive strokes thus using much of the pressure energy before exhaust occurs by the pistons themselves rather than to dump it as is usually done.