Method of an internal combustion engine with two by three clocks

Abstract

Cylinder arrangement (1) of an internal combustion engine, comprising a piston (20) designed to move translationally back and forth in a cylinder (10) and to delimit a combustion chamber (14) within the cylinder (10), a connecting rod (30) designed to connect the piston (20) to a planet gear (40) by means of a connecting element (42), wherein the connecting element (42) is arranged eccentrically on the planet gear (40) and the planet gear (40) engages with and rotates in a ring gear (50) and is also connected to a crankshaft (60), wherein the dimensions of the planet gear (40) and the eccentric arrangement of the connecting element (42) are further configured such thatthat the piston (20) reaches a first top dead center (TDC') twice and a second top dead center (TDC") once, and a first bottom dead center (BDC') twice and a second bottom dead center (BDC") once in three revolutions of the planet gear (40) in the ring gear (50), wherein the first top dead center (TDC') and the first bottom dead center (BDC') are further away from an axis of the ring gear than the second top dead center (TDC") and the second bottom dead center (BDC) respectively.

Description

[0001] The invention relates to a cylinder arrangement of an internal combustion engine (motor) and an internal combustion engine.

[0002] Against the background of constantly increasing demands on modern internal combustion engines with regard to their energy efficiency and related topics, there is a constant effort to optimize the operation of internal combustion engines.

[0003] According to the state of the art, two essentially different types of work cycles are known for internal combustion engines, which simultaneously require internal combustion engines or cylinder arrangements of different designs. The work cycles are divided into strokes, with one stroke being defined by the movement of the piston during half a revolution of the crankshaft. Thus, two strokes are required for one complete revolution of the crankshaft. If the strokes repeat after just one revolution, the engine is referred to as a two-stroke engine, whereas internal combustion engines in which the cycle repeats after two revolutions, i.e. four strokes, are referred to as four-stroke engines. Thus, in a two-stroke engine, a cycle is completed after just one revolution, whereas in a four-stroke engine it is only completed after two revolutions.

[0004] In two-stroke engines, in a first stroke, a gas mixture is admitted into the combustion chamber, which is formed by a cylinder and a piston moving in translation within it, and is compressed there by a piston movement from bottom dead center to top dead center. Bottom dead center is defined as the position of the piston at which the combustion chamber has its maximum volume. Correspondingly, top dead center is defined as the position of the piston at which the combustion chamber has its minimum volume. The inflowing gas mixture can already be a fuel-air mixture or just fresh air. Around top dead center of the piston movement, fuel is injected into the combustion chamber if not already contained in the intake gas mixture, and the gas mixture is ignited. In the context of this application, the term gas mixture does not refer exclusively to an air-fuel mixture, but merely to a gas of any composition.For example, a combusted air-fuel mixture can be referred to as a gas mixture, just as can air alone. In gasoline engines, ignition is achieved by a spark plug. The ignition of the gas mixture causes it to burn, causing the pressure in the combustion chamber to rise sharply. In diesel engines, ignition occurs due to the high temperature in the area of ​​maximum compression and the self-igniting fuel.

[0005] This accelerates the piston towards bottom dead center in a second stroke, whereby power is transferred to the crankshaft via a connecting rod. When the piston reaches an outlet on its way towards bottom dead center and opens it, the ignited or combusted gas mixture escapes through this outlet and the pressure in the combustion chamber drops. On the way to bottom dead center, the piston also opens an inlet through which fresh air enters the combustion chamber and forces all or part of the combusted gas mixture out of the exhaust. This process is also known as scavenging. The residual momentum of the power delivery causes the piston to move towards top dead center again, completing the working cycle of the two-stroke engine and starting the first stroke again.

[0006] The advantage of the two-stroke engine is that power is delivered with every revolution of the crankshaft, thus enabling high performance. However, the disadvantages are high wear, fuel consumption, and emissions, as well as comparatively low component durability due to the high thermal and mechanical stress.

[0007] To overcome these disadvantages, the four-stroke engine, which is now the most commonly used engine in motor vehicles, was developed. The first stroke is characterized by the intake of a gas mixture (here, either fresh air with subsequent injection of fuel or an air-fuel mixture) through an intake valve. This occurs while the piston moves from top dead center to bottom dead center. Once the maximum combustion chamber volume is reached and the piston is at its reversal point (here, bottom dead center), the intake valve is closed, and the gas mixture trapped in the combustion chamber is compressed by the piston's movement from bottom to top dead center, which characterizes the second stroke.Here, too, the gas mixture is ignited at top dead center, i.e., at maximum compression, creating excess pressure in the combustion chamber, which in turn accelerates the piston toward bottom dead center and thus delivers power to the crankshaft (third stroke). The combusted gas mixture is then expelled from the combustion chamber via an exhaust valve in a fourth stroke.

[0008] The four-stroke engine has significantly reduced emissions and fuel consumption compared to a two-stroke engine, and significantly increased engine reliability and durability. However, power output is reduced, as only one power output occurs in two revolutions of the crankshaft.

[0009] Other methods for operating an internal combustion engine and corresponding internal combustion engines are also known in the prior art. For example, document WO2010069027 discloses a three-stroke internal combustion engine with two connecting rods connected to each other by the crankshaft so as to move toward or away from each other. An exhaust / filling step, a compression step, and an expansion step are performed during one crankshaft rotation. Openings in the cylinders are arranged near the crankshaft.

[0010] Patent document CH714074A2 discloses an internal combustion engine with a three-stroke cycle. The cycle corresponds to a two-stroke cycle with an additional cycle for scavenging. The time for more thorough scavenging is achieved by a triangular movement on the crankpin. This is achieved, for example, via a pinion and a rolling circle gear with a diameter ratio of 1:3 or 2:3. Thus, the piston is fully raised and lowered once or twice during every three revolutions of the crankshaft (1080°).

[0011] Document CN112953110A discloses an electromagnetic three-stroke piston engine with a planetary gear. Document WO2022087759A1 discloses a free-piston internal combustion engine with two coupled pistons for driving a hydraulic motor using a three-stroke principle.

[0012] Against the background of the prior art described above, it is the object of the present invention to provide a novel cylinder arrangement and an internal combustion engine which combine the advantages of two-stroke and four-stroke processes.

[0013] This object is achieved by a cylinder arrangement according to claim 1 and an internal combustion engine according to claim 7. Advantageous embodiments of the invention are contained in the subclaims.

[0014] A method for operating an internal combustion engine comprises a working cycle (total cycle) of three revolutions of a crankshaft of the internal combustion engine. During this cycle, the piston of the internal combustion engine passes through a first top dead center twice and a second top dead center once, and through a first bottom dead center twice and a second bottom dead center once, with the first top dead center and the first bottom dead center being farther away from the crankshaft than the second top dead center and the second bottom dead center, respectively. The method further comprises the following strokes: (A) Supplying a fuel mixture into a combustion chamber of the cylinder during the movement of the piston from the second top dead center to the first bottom dead center, (B) Compressing the air-fuel mixture in the combustion chamber of the cylinder during the movement of the piston from the first bottom dead center to the first top dead center, (C) Combusting the air-fuel mixture during the movement of the piston from the first top dead center to the second bottom dead center, (D) Compressing a gas mixture present in the combustion chamber at that time during the movement of the piston from the second bottom dead center to the first top dead center, (E) Combusting the gas mixture during the movement of the piston from the first top dead center to the first bottom dead center, (F) Expelling the gas mixture present in the combustion chamber during the movement of the piston from the first bottom dead center to the second top dead center.

[0015] Furthermore, as the piston passes through the second bottom dead center, at least a portion of the gas mixture in the combustion chamber is flushed out. Passing through the second bottom dead center refers to the movement of the piston, which moves in one direction until bottom dead center and then reverses its movement in the opposite direction at bottom dead center.

[0016] Due to the purging of the combustion chamber during passage through the second bottom dead center, the combustion of the air-fuel mixture in process step (C) only occurs until the onset of purging, which preferably occurs when the first bottom dead center is passed. Similarly, the compression of the gas mixture according to process step (D) also only occurs when the purging of the combustion chamber during passage through the second bottom dead center is completed, which preferably also occurs when the first bottom dead center is passed, this time in the opposite direction.

[0017] The term "fuel mixture" mentioned in process step (A) refers both to a fuel mixture that is already injected into the cylinder's combustion chamber as a fuel-air mixture or drawn in through the intake valve, and to a fuel-air mixture that is only formed in the combustion chamber by the intake of fresh air and the injection of fuel. It can also refer to the residual gas that remains combusted or partially combusted in the combustion chamber after combustion.

[0018] The process is therefore a process with six individual strokes, whereby these strokes can be divided into two three-stroke sequences. Both three-stroke sequences each have a combustion stroke, in which power is delivered to the crankshaft. Thus, in the context of this application, it is referred to as a three-stroke process, even though six strokes are required to form a complete working cycle of the internal combustion engine with two working strokes. The camshaft rotates three times slower than the crankshaft. The two individual three-stroke processes are also referred to as working cycles.

[0019] Due to the fact that at least a portion of the gas mixture in the combustion chamber is flushed out as the piston passes through the second bottom dead center, the process incorporates all the process steps of both a four-stroke and a two-stroke engine, with the power output being increased by twice the power output within the six individual strokes compared to a four-stroke engine. At the same time, the clean and complete combustion of the fuel mixture eliminates the disadvantages of the two-stroke process.

[0020] In a preferred embodiment, the combustion chamber is purged in the region of the second bottom dead center using at least one purge opening arranged radially in the cylinder. This can be dimensioned according to the amount of gas to be purged, or divided into several smaller openings in order to optimize purging. A gas mixture enters the combustion chamber through the at least one purge opening, wherein the gas mixture previously expanded by the combustion process in the combustion chamber was previously discharged from the combustion chamber, preferably through an exhaust valve or another outlet opening. Embodiments are also conceivable in which the purge openings are also used to discharge the gas mixture present in the combustion chamber.

[0021] In a further preferred embodiment, a fuel mixture is supplied to the combustion chamber during the piston's movement from the second bottom dead center to the first top dead center, in particular injected through the intake valve or supplied through the scavenging openings. Particularly preferably, the injection takes place during scavenging of the combustion chamber shortly after the piston passes through the second bottom dead center, i.e., before the piston reaches the first bottom dead center. This additional supply of fuel mixture allows the gas mixture in the combustion chamber to be optimally prepared for the second combustion during the second power output, thereby ensuring optimal power output and clean combustion.

[0022] To implement the method, it is necessary to ensure the movement of the piston between the dead centers. Therefore, the method is not applicable to every internal combustion engine or every cylinder arrangement. The term "cylinder arrangement" refers to the arrangement of a cylinder including the piston, connecting rod, and mounting on a crankshaft. An internal combustion engine according to the invention comprises several cylinder arrangements with a common crankshaft.

[0023] The cylinder arrangement of an internal combustion engine according to the invention has a piston which is designed to move in a translationally oscillating manner back and forth in a cylinder and to delimit a combustion chamber within the cylinder. The cylinder arrangement further comprises a connecting rod which is designed to connect the piston to at least one planetary gear by means of a connecting element, wherein the connecting element is arranged eccentrically on the planetary gear and the planetary gear engages with and rotates in a ring gear and is also connected to a crankshaft. A connecting element arranged eccentrically on the planetary gear is defined in that the geometric center of the connecting element does not coincide with the geometric center of the planetary gear, but has an eccentricity.Furthermore, the dimensions of the planetary gear and the eccentric arrangement of the connecting element are designed such that the piston reaches a first top dead center twice and a second top dead center once in three revolutions of the planetary gear or the crankshaft in the ring gear and twice a first bottom dead center and once a second bottom dead center, wherein the first top dead center and the first bottom dead center are further away from an axis of the crankshaft than the second top dead center and the second bottom dead center, respectively.

[0024] To enable the required work cycle of the process, the diameter of the planetary gear is preferably three-fifths of the diameter of the ring gear. The diameter is understood to be the pitch diameter of a gear (i.e., planetary gear or ring gear). The speed ratio between the planetary gear and the crankshaft is preferably two to three.

[0025] This arrangement, particularly the eccentric mounting of the connecting element on the planetary gear, forces the geometric center of the connecting rod's connecting element to the planetary gear onto a hypocycloidal path, resulting in the different dead centers. The dimensioning of the eccentricity defines the distances between the dead centers.

[0026] In an advantageous embodiment of the invention, the cylinder has at least one scavenging opening between the first bottom dead center and the second bottom dead center, which is designed to scavenge the combustion chamber when the piston is below the first bottom dead center and thus exposes the scavenging opening. In this way, a simple option for scavenging the combustion chamber can be provided. Embodiments are conceivable in which the gas mixture in the combustion chamber is discharged and a fresh gas mixture is introduced through the scavenging openings, or in which only fresh gas mixture is introduced, while the discharge of the gas mixture in the combustion chamber is ensured via another exhaust opening or an exhaust valve.

[0027] A further preferred embodiment of the cylinder arrangement according to the invention is one in which the connecting element between the connecting rod and the planetary gear is formed by an eccentrically arranged, particularly cylindrical, element, which is enclosed by a connecting rod eye arranged at one end of the connecting rod. Such an arrangement represents a simple way of establishing the connection between the connecting rod and the planetary gear.

[0028] In a further preferred embodiment of the invention, the cylinder arrangement has at least one inlet valve for supplying a gas mixture, in particular a fuel-air mixture, into the combustion chamber and at least one outlet valve for discharging a gas mixture from the combustion chamber.

[0029] Such valves can be easily controlled via valve trains, thus providing an efficient way to supply the combustion chamber with a fuel-air mixture. It is also conceivable to provide multiple valve openings within one cycle. However, designs with multiple intake or exhaust valves are also conceivable.

[0030] In a preferred embodiment of the invention, the ring gear is rotatable through a defined angular position. This also causes the planetary gear to rotate, changing the orientation of the eccentricity with which the connecting element of the connecting rod is attached to the planetary gear. Consequently, the dead centers are slightly changed, which affects the compression ratio in the combustion chamber and in particular the control of the valves, especially the intake valve. In this way, the valve timing can be adjusted by slightly rotating the ring gear through a defined angular position. With an appropriate arrangement of the scavenging openings, the rotation of the ring gear can also partially mask the scavenging openings, thus influencing the scavenging of the combustion chamber.

[0031] Preferably, the rotation of the ring gear occurs via an external thread located on the outside of the ring gear. The ring gear can be rotated by a gear engaging this external thread.

[0032] In a particularly preferred embodiment of the invention, the geometric dimensions of the ring gear, the planetary gear, and the distance between the eccentrically arranged connecting element of the connecting rod and the geometric center of the planetary gear are selected such that the ratio between the distance between the first top dead center and the first bottom dead center and the distance between the first top dead center and the second bottom dead center is between 0.7 and 0.85. The distance of the eccentric connecting element to the geometric center of the planetary gear is defined by the distance between the connection point of the connecting element on the planetary gear and the geometric center of the planetary gear. With such a ratio, particularly advantageous operation of the internal combustion engine can be ensured with regard to clean combustion and power development.

[0033] The internal combustion engine according to the invention has at least one cylinder arrangement according to the invention. The number of cylinders is preferably a multiple of 3. An internal combustion engine according to the invention can be available in various designs and thus with different geometric arrangements of the individual cylinder arrangements. It can thus be implemented, for example, as an in-line engine, V-engine, W-engine, or boxer engine.

[0034] It should be noted that the method features disclosed in the application are also deemed to be disclosed for the device according to the invention and vice versa.

[0035] Embodiments and advantageous aspects of the invention are explained in more detail below with reference to the accompanying figures. They show: Fig. 1 perspective view of an embodiment of a piston arrangement 1 according to the invention, Fig. 2 detailed view of a planetary gear 40 of a piston arrangement 1 according to the invention, Fig. 3 cross-section of a cylinder 10 and movement path of the center point of the connecting element 42 for fastening the connecting rod 30 to the planetary gear 40, Fig. 4a detailed view of the piston arrangement 1 according to. Fig. 1 , wherein the piston 20 is in the second bottom dead center UT", Fig. 4bDetail view of the cylinder 10, wherein the piston 20 is in the second bottom dead center UT", Fig. 5aDetail view of the piston arrangement 1 according to. Fig. 1 , wherein the piston 20 is located at the first bottom dead center UT', Fig. 5bDetail view of the cylinder 10, wherein the piston 20 is located at the first bottom dead center UT', Fig. 6Diagram illustrating the movement sequence of a piston 20 in a piston arrangement 1 according to the invention plotted against the crank angle, Fig. 7Schematic view of a piston arrangement 1 according to the invention in a second embodiment with variable control times of the intake valve.

[0036] Fig. 1 shows a perspective view of an embodiment of a piston arrangement 1 according to the invention. The piston arrangement 1 has a cylinder 10 in which a piston 20 performs a linear movement. The cylinder 10 is shown in section for better illustration. Cylinder 10 and piston 20 enclose a combustion chamber 14, the volume of which changes depending on the movement of the piston 20 in the cylinder 10. On one end of the cylinder 10, i.e. on the cylinder cover, an inlet valve 12 and an exhaust valve 13 are arranged to guide a gas mixture into the combustion chamber 14 and to discharge it from the combustion chamber 14. The valves are controlled via a camshaft 70 and inlet cams 71 and exhaust cams 72 correspondingly attached thereto. Embodiments with multiple inlet valves 12 and exhaust valves 13, which are controlled in particular via multiple camshafts 70, are also conceivable.Furthermore, the cylinder 10 has radial scavenging openings 11 at a fixed height, by means of which the combustion chamber can be scavenged when the piston 20 is in the corresponding position.

[0037] The piston 20 is connected via a connecting rod 30 to two planetary gears 40, each rotating in a ring gear 50. It is also possible to provide only one planetary gear 40 and correspondingly one ring gear 50. For the sake of simplicity, only one planetary gear 40 and one ring gear 50 will be referred to below, since the movement of the two planetary gears 40 is synchronous. A crankshaft 60 is connected to the planetary gear 40, which, as in prior art internal combustion engines, provides the power of the engine for use and connects different piston assemblies 1 to one another. According to the invention, the connection of the connecting rod 30 to the planetary gear 40 is eccentric, i.e. not in the geometric center of the planetary gear 40, which is important with regard to Fig. 2 will be discussed in more detail.

[0038] Fig. 2 shows a detailed view of the planetary gear 40 as it is in the embodiment of the piston arrangement 1 according to. Fig. 1 is used. It has external teeth 43, which mesh with the teeth of the ring gear 50. The connection of the connecting rod 30 to the planetary gear 40 is realized via a connecting element 42. In the embodiment shown, this is cylindrical and arranged on the side surface of the planetary gear 40. The receptacle 41 for the crankshaft 60 is arranged in the geometric center of the planetary gear 40.

[0039] The geometric center M of the cylindrical connecting element 42 does not coincide with the geometric center K of the planetary gear 40. The connecting element 42 is therefore arranged eccentrically on the side surface of the planetary gear 40, whereby the eccentricity e, i.e. the distance of the geometric center M of the connecting element to the geometric center K of the planetary gear 40, represents an important parameter for the piston movement, as with regard to Fig. 3 is explained in more detail.

[0040] Fig. 3 shows a cross-section of the cylinder 10 and the movement of the geometric center M of the connecting element 42. The movement of a point of the piston corresponds to the movement of the geometric center M of the connecting element 42 in the y-direction of the diagram. The cylinder 10 corresponds to the already in Fig. 1 shown cylinder 10. By the with regard to Fig. 2 Due to the eccentricity e explained above, the linearly oscillating axial movement of the piston 20 within the cylinder 10 does not always run between the two same end points, as is known in the prior art. These are conventionally referred to as top and bottom dead center (TDC, BDC) and each mark the turning point of the piston 20 during the axial movement. Due to the eccentricity e in the piston arrangement 1 according to the invention, the movement takes place between two top and two bottom dead centers. As will be explained later with regard to Fig. 6 As will be explained in more detail, one working cycle (total cycle with two working cycles / working strokes) of the piston arrangement according to the invention comprises three revolutions of the crankshaft 60. This means that the planetary gear 40 also rotates three times within the ring gear 50. Due to the eccentricity e, the geometric center M of the connecting element 42 does not run on a circular path during one revolution. However, if three revolutions of the crankshaft 60 are completed, the geometric center M is again at the same point. The movement path of the geometric center M of the connecting element 42 is on the right side of the Fig. 3 shown, wherein the movement path of an upper point of the piston 20 corresponds to the movement path of the geometric center M of the connecting element 42 and thus the diagram can be transferred in the y-direction to an upper point of the piston 20.

[0041] This hypocycloid curve has three maxima, which are to be understood as top dead centers, and three minima, which are to be understood as bottom dead centers. Two maxima are higher than the third maximum, and one minimum is lower than the other two minima. Thus, the two higher maxima form the first top dead center (TDC), and the lower maximum forms the second top dead center (TDC). Analogously, the two higher minima form the first bottom dead center (BDC), and the one lower minimum (the global minimum of the motion curve) forms the second bottom dead center (BDC).

[0042] By translating the hypocycloid motion of the geometric center M of the connecting element 42 into a linear axial alternating movement of the piston 20, the piston 20 moves between the second bottom dead center BDC" and the first top dead center TDC' during one working cycle, whereby the first top dead center TDC' is reached twice and the second top dead center TDC" once. Analogously, the first bottom dead center BDC' is reached twice and the second bottom dead center BDC" once. The scavenging openings 11 are arranged in the cylinder 10 such that they are only opened when the piston 20 passes through the second bottom dead center BDC". The greater the eccentricity e, the more the hypocycloid motion of the geometric center M of the connecting element 42 deviates from a circular path and consequently the greater the difference between the respective first and second dead centers.The aim is to achieve the most even compaction possible for both work cycles.

[0043] The formation of different top and bottom dead centers will continue in the Figs. 4a, 4b and 5a and 5b are explained in more detail. Figs. 4a und 5a show the piston arrangement 1 according to the invention in different positions of the working cycle. Fig. 4a the planetary gear 40 is located within the ring gear 50 in the position furthest from the cylinder 10. The planetary gear 40 is oriented such that the eccentricity e points downwards in the plane of the drawing, i.e. the connecting element 42 is located further away from the cylinder 10 than the geometric center of the planetary gear 40. Thus, the piston 20 is located at the second bottom dead center UT", i.e. the global minimum in the movement path from Fig. 3 . As a result, as in Fig. 4b schematically shown the radial scavenging openings 11 in the cylinder 10, which is shown here in a section, are exposed by the piston 20.

[0044] In Fig. 5a the planetary gear 40 is again at the point furthest from the cylinder 10 in the ring gear 50, namely exactly one revolution of the planetary gear 40 in the ring gear 50 later. However, the geometric center M of the connecting element 42 is not at the same point after one revolution of the planetary gear 40 in the ring gear 50, but is in the plane of the drawing of the Fig. 5a to the top left. As a result, the piston 20 is at the first bottom dead center UT' in the cylinder 10, where it covers the scavenging openings 11 and thus does not allow the gas mixture to escape from the combustion chamber 14 through the scavenging openings 11, as in Fig. 5b shown.

[0045] Fig. 6 shows a diagram illustrating the movement sequence of the piston 20 in the cylinder 10 of a piston arrangement 1 according to the invention. Fig. 6 the working cycle of the piston arrangement 1 according to the invention and thus the method in connection with Fig. 1 described in more detail.

[0046] The entire cycle encompasses a crankshaft rotation of 1080°, corresponding to three full crankshaft revolutions. It is divided into a total of six strokes, each of which encompasses 180°, or half a crankshaft revolution. The diagram shows the angle of the crankshaft 6° on the x-axis, i.e., the crankshaft rotation, and the stroke of piston 20 within cylinder 10 on the y-axis. The specific numerical values ​​are given here only as examples.

[0047] In the initial position shown, the piston 20 is at the second top dead center OT". From there, it moves in the first stroke towards the first bottom dead center UT'. During this movement, the intake cam 71 opens on the camshaft 70 (see Fig. 1 ) the intake valve 12, whereby an air-fuel mixture enters the combustion chamber 14. In an alternative embodiment, it is also possible for only fresh air to enter the combustion chamber through the intake valve and, in the following compression stroke, to be mixed with an injected fuel to form a fuel-air mixture.

[0048] After reaching the first bottom dead center (BDC), the volume of the combustion chamber 14 is reduced again by the movement of the piston 20 toward the first top dead center (TDC). In the process, the gas mixture in the combustion chamber 14 is compressed, which is why this stroke can be described as a compression stroke. During this stroke, the intake valve 12 is closed again to prevent the gas mixture from escaping. The first two strokes are thus also known from a four-stroke engine, although, unlike a four-stroke engine, the piston movement encompasses two different top dead centers.

[0049] When the first top dead center (TDC) is reached or shortly before, the gas mixture is ignited. For this purpose, gasoline engines use a spark plug like those in conventional internal combustion engines, whereas in diesel engines, the compression is so high that the gas mixture ignites itself due to the high pressure and the resulting increase in temperature. The ignition of the gas mixture greatly increases the pressure in the combustion chamber 14, causing the piston 20 to accelerate during its movement in the third stroke from the first top dead center (TDC)' to the second bottom dead center (BDC). This allows the power to be transferred to the crankshaft 60 via the connecting rod 30.

[0050] When the piston 20 reaches the first bottom dead center BDC', it releases the scavenging ports 11 arranged radially in the cylinder 10, whereby the combustion chamber 14 is scavenged. The scavenging ports 11 are open while the piston 20 passes the second bottom dead center BDC" until the piston 20 passes the first bottom dead center BDC' or the scavenging ports 11 again in the fourth stroke. During scavenging, which thus occurs in the transition between two strokes, it is also possible, but not necessary, for the intake valve 12 to open, allowing fresh gas mixture to flow into the combustion chamber from the cylinder cover, provided the pressure in the combustion chamber 14 is lower than the pressure with which the fresh gas mixture flows into the combustion chamber 14. Preferably, the exhaust valve 13 opens at least partially during the scavenging process (see Fig. 3 ), so that the gas mixture can at least partially escape via the exhaust valve during the purging process. The purging process preferably takes place in such a way that a fresh gas mixture flows in through purge openings 11 at the bottom of the combustion chamber 14, while the gas mixture located in the combustion chamber 14 is expelled through the exhaust valve 13. The use of several exhaust valves 13, with only a portion being used for purging, is just as conceivable as embodiments in which both the outlet and the inlet of the gas mixture during the purging process are at least partially realized via appropriately arranged purge openings 11.

[0051] As soon as the piston 20 closes the scavenging ports 11 on its renewed movement toward the first top dead center (TDC) during the fourth stroke, scavenging is completed (whereby the exhaust valve 13, if open, also closes), and the remaining gas mixture in the combustion chamber 14 is compressed again and then ignited again, i.e., for a second time within a working cycle. During the compression process, the optionally opening valves are closed again. The fourth and fifth strokes thus largely correspond to the strokes familiar from a two-stroke engine.

[0052] Due to the renewed, i.e., second, ignition of the gas mixture in the fifth stroke, a second power delivery to the crankshaft 60 occurs within the working cycle, with the piston 20 only reaching the first bottom dead center (TDC). In this second combustion stroke (power delivery), the remaining combustion components contained in the gas mixture are completely combusted, allowing for particularly clean and complete combustion.

[0053] After passing the first bottom dead center UT', a valve plate 131 of the exhaust valve 13 is lifted from its valve seat 132 and the combusted gas mixture remaining in the combustion chamber 14 is expelled through the exhaust valve 13. The exhaust cam 72 (see Fig. 1 ) comprises, in the embodiment shown, two elevations for opening the exhaust valve 13 during the scavenging process and the exhaust stroke (stroke 6). After reaching the second top dead center (TDC), a working cycle is completed, and the strokes begin again. Of course, embodiments of the invention with independently controllable valve trains, as well as embodiments without a camshaft, are also conceivable in order to variably control the opening and closing times of the intake valve 12 and the exhaust valve 13.

[0054] Due to the fact that two combustions and thus power outputs occur during one working cycle, i.e., the total cycle of six strokes, the engine according to the invention is a three-stroke engine, with two different three-stroke cycles being carried out alternately. One could therefore also speak of a two-by-three-stroke engine. Both compression strokes occur between the first bottom dead center (BDC) and the first top dead center (TDC), thereby ensuring a constant compression ratio for the respective subsequent combustions.

[0055] Fig. 7 essentially shows the crankshaft arrangement from Fig. 1 , which is why we will only discuss the differences here. In contrast to the embodiment according to Fig. 1 , the embodiment according to Fig. 7 additionally has an external thread 51, which extends over half the circumference on the outside of the ring gear 50.

[0056] By rotating the gear 80, the ring gear 50 can rotate about the crankshaft 60. This also causes the planetary gear 40 to rotate, slightly shifting the eccentricity with which the connecting element 42 connects the connecting rod 30 and the planetary gear 40. Consequently, the dead centers are also shifted, since the shift in the eccentricity means that the extremes of the piston movement are no longer identical. This has the effect, on the one hand, that the volume available for compression within the combustion chamber 14 and thus the compression ratio of the gas mixture in the combustion chamber 14 is changed, but on the other hand, in particular, that the opening and closing times, in particular of the intake valve, are changed, and thus control of these times can be achieved by rotating the ring gear 50.

Claims

1. Cylinder arrangement (1) of an internal combustion engine, comprising a piston (20) which is designed to move translationally back and forth in a cylinder (10) and to delimit a combustion chamber (14) within the cylinder (10), a connecting rod (30) designed to connect the piston (20) to a planetary gear (40) by means of a connecting element (42), wherein the connecting element (42) is arranged eccentrically on the planetary gear (40) and the planetary gear (40) engages with a ring gear (50) and rotates therein and is also connected to a crankshaft (60), wherein furthermore the dimension of the planetary gear (40) and the eccentric arrangement of the connecting element (42) are designed such thatthat the piston (20) in three revolutions of the planetary gear (40) in the ring gear (50) reaches twice a first top dead center (OT') and once a second top dead center (OT") and twice a first bottom dead center (UT') and once a second bottom dead center (UT"), wherein the first top dead center (OT') and the first bottom dead center (UT') are further away from an axis of the ring gear than the second top dead center (OT") and the second bottom dead center (UT"), respectively.

2. Cylinder arrangement (1) according to the preceding claim, wherein the cylinder (10) has at least one scavenging opening (11) between the first bottom dead center (UT') and the second bottom dead center (UT"), which is designed to divert a gas mixture from the combustion chamber (14).

3. Cylinder arrangement (1) according to one of the preceding claims 1 and 2, wherein the connecting element (42) between the connecting rod (30) and the planetary gear (40) is formed by an eccentrically arranged, in particular cylindrical element, which is enclosed by a connecting rod eye (31) arranged at the end of the connecting rod (30).

4. Cylinder arrangement (1) according to one of the preceding claims 1 to 3, wherein the cylinder arrangement (1) has at least one inlet valve (12) for supplying a fuel-air mixture into the combustion chamber (14) and an outlet valve (13) for discharging a gas mixture from the combustion chamber (14).

5. Cylinder arrangement (1) according to one of the preceding claims 1 to 4, wherein the ring gear (50) is arranged rotatably about the crankshaft (60).

6. Cylinder arrangement (1) according to the preceding claim, wherein an external thread (51) is arranged on the outside of the ring gear (50), which is designed to rotate the ring gear (50) about the crankshaft (60).

7. Internal combustion engine comprising at least one cylinder arrangement (1) according to one of the preceding claims 1 to 6.

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