Method for operating an internal combustion engine for a motor vehicle, and internal combustion engine for a motor vehicle

A method for operating an internal combustion engine of a motor vehicle having a cylinder, the combustion chamber of which is delimited in the radial direction by a cylinder wall and in the axial direction by a piston and by a combustion chamber roof. The piston has an annularly peripheral piston stage which is arranged axially recessed in the piston compared with an annularly peripheral piston crown and which merges via an annularly jet splitter contour into a piston hollow arranged axially recessed in the piston in relation to the piston stage. An injector is allocated to the cylinder and via the injector several injection jets are simultaneously injected directly into the combustion chamber in a star shape for a combustion process.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a method for operating an internal combustion engine for a motor vehicle. Furthermore, the invention relates to an internal combustion engine for a motor vehicle.

Such a method for operating an internal combustion engine for a motor vehicle and such an internal combustion engine are already known from DE 10 2011 119 215 A1. The method is a burning method, also referred to as a combustion method, according to which the internal combustion engine is operated in its fired operation. Here, the internal combustion engine has at least one cylinder whose combustion chamber is delimited in the radial direction of the cylinder by a cylinder wall, in the axial direction of the cylinder on one side by a piston received translationally moveably in the cylinder and in the axial direction of the cylinder on the other side by a combustion chamber roof of the internal combustion engine. The combustion chamber roof is formed, for example, by a cylinder head of the internal combustion engine. The piston has an annularly peripheral piston stage which is arranged axially recessed in the piston compared with an annularly peripheral piston crown and which merges via an annularly peripheral jet splitter contour into a piston hollow arranged axially recessed in the piston in relation to the piston stage.

Moreover, the internal combustion engine has at least one injector allocated to the cylinder, by means of which injector several injection jets are simultaneously injected directly into the combustion chamber in a star shape for a combustion process and preferably within a work cycle of the internal combustion engine. By means of the jet splitter contour, the injection jets are respectively divided into a first subset entering into the piston hollow, into a second subset entering via the piston stage into a region between the piston crown and the combustion chamber roof and into third subsets. The respective injection jet and thus the respective subset are formed from an in particular liquid fuel, by means of which the internal combustion engine is operated in its fired operation. Thus, the fuel is injected directly by means of the injector, in particular by forming the injection jets. The third subsets extend starting from the respective injection jets on both sides in the peripheral direction of the piston in opposite directions along the piston stage and collide between two adjacent injection jets inside the piston stage and are deflected radially inwards from the piston stage. Here, the first subset forms a first combustion front and the second subset forms a second combustion front. Furthermore, the third subsets respectively inwardly deflected together form a third combustion front radially inwardly into a gap between adjacent injection jets. By means of a resulting current in the combustion chamber formed at least from a swirl, a crushing gap current and a jet current, the injection jets are deflected up-jet or upstream of the jet splitter contour in the direction of the piston.

By means of this measure, the injection jets can be deflected towards the piston removed from the cylinder head during a beginning expansion stroke in a work cycle. As a result, the injection jets can also furthermore impinge upon the jet splitter contour when the pistons are removed from the cylinder head or upon on the piston in the region of the jet splitter contour in order to further distribute the respective injection jet into three subsets. In doing so, a longer period of time or an extended crankshaft angle is available for the optimum distribution of the respective injection jets. As a result of the variation of injection duration, pressure and timing, in particular of the start of the injection, third subsets can be generated reproducibly via an extended characteristic diagram region with sufficiently great fuel mass and fuel speed and thus with an impulse inherent to sufficiently large third subsets, such that the third combustion front is formed in a gap between two adjacent injection jets and thus can optimally use combustion air distributed spatially in the combustion chamber, whereby combustion can be improved and, in particular, soot emissions can be reduced. Furthermore, with the deflection of the injection jet according to the invention, the wetting of the cylinder wall with fuel of the second subset is at least greatly reduced, since the injection jet substantially impinges upon the jet splitter contour or on adjacent regions of the piston and does not coat the piston crown and impinge directly upon the cylinder wall. Moreover, the third subsets are separated from the respective injection jets by means of the piston stage, such that less fuel is available for the second subset, whereby the impulse inherent to the second subset becomes smaller and thus the penetration depth of the second subset is reduced. Moreover, the axial deflection of the second subset in the piston stage towards the cylinder head leads to a build-up of the second subset between the cylinder head and the piston, such that the fuel flowing through the injection into the second combustion front is reduced, whereby the radial expansion of the second subset or the second combustion front is restricted. Advantageously, by means of these two effects, contact of the second combustion front on the relatively cold cylinder or the cylinder wall can be minimized, such that unwanted heat transfer between the second combustion front with the cylinder wall can be greatly reduced, whereby soot formation from the second combustion front on the relatively cold cylinder wall can be reduced. Moreover, ablution of oil from the cylinder wall and an input of soot into the engine oil can be reduced.

Moreover, DE 10 2006 020 642 A1 discloses a method for operating a directly injecting, self-igniting internal combustion engine. Furthermore, an internal combustion engine is known from DE 10 2011 017 479 A1.

The object of the present invention is to develop a method and an internal combustion engine of the kind mentioned at the start in such a way that combustion of the injected fuel can be further improved and combustion air spatially distributed in the combustion chamber can be used in a further optimized manner.

In order to develop a method of the kind in such a way that a particularly optimized combustion can be achieved by a particularly high utilization of the combustion air present in a combustion chamber, it is provided according to the invention that, in the piston stage, i.e., in a stage chamber of the piston stage, first deflection means and/or second deflection means are arranged, wherein the injection jets are distributed by means of first deflection means in the piston stage into third subsets and/or the second deflection means deflect the respective third subset from the peripheral direction in the radial direction inwardly and thus, in particular, in the direction of the gaps between adjacent injection jets, in particular in the direction of the injector. The piston stage has, for example, a stage wall also referred to as a side wall, by means of which, for example, the piston stage or its stage chamber is delimited in the radial direction outwards at least partially, in particular at least predominantly or completely. The respective first and/or the second deflection means protrude inwardly from the side wall in the radial direction, such that the respective deflection means is, for example, a protrusion or a nose, which protrudes in the radial direction inwardly into the stage chamber and here projects in the radial direction inwardly into the stage chamber. In particular, the first deflection means, for example, are arranged to be spaced apart from one another in the peripheral direction of the piston. Preferably, in the peripheral direction of the piston, the deflection means are arranged distributed evenly or respectively at an impingement point of the injection jets on the jet splitter contour in the piston stage or in the stage chamber. Advantageously, using the first deflection means, the injection jets striking the jet splitter contour can be supported in terms of their distribution in the peripheral direction in third subsets, such that smaller fuel masses of third subsets and/or third subsets of injection jets with low impulse in the piston stage also have a sufficiently high speed, whereby a third combustion front can form in a gap between two adjacent injection jets. Alternatively to or in combination with the first deflection means, the second deflection means are arranged to be spaced apart from one another in the peripheral direction of the piston. Preferably, the second deflection means are arranged to be distributed evenly and centrally in the piston stage or in the stage chamber between two adjacent injection jets in the peripheral direction of the piston. Advantageously, using the second deflection means, the third subsets can be supported in terms of their deflection radially inwardly, such that smaller fuel masses of third subsets also form a third combustion front in a gap between two adjacent injection jets when colliding, whereby the combustion is also improved with third subsets with respective smaller impulse. Advantageously, using the second deflection means, third subsets can also be supported in terms of their deflection radially inwardly, which are formed from the injection jets further removed from one another in the piston stage. Here, the injector injects fewer injection jets, such that an angle between adjacent injection jets and thus the distance between adjacent injection jets when impinging upon the piston stage is greater, whereby the third subsets collide at low speed because of the further distance in relation to one another and thus have a lower impulse.

Furthermore, it is provided according to the invention that the injection jets are injected directly into the combustion chamber in the form of first jet cones each with a first jet breakup. Furthermore, it is provided according to the invention that, by means of the injector, several second injection jets provided in addition to the first injection jets in the form of second jet cones are simultaneously injected directly into the combustion chamber for the combustion process. Here, the second injection jets are each injected with a second jet breakup different from the first jet breakup. For example, the at least one first jet breakup is smaller than the at least one second jet breakup.

By means of the jet splitter contour, at least the first injection jets, for example, are divided into the first subset, the second subset and the third subsets. Here, it can be provided that, by means of the jet splitter contour, only or exclusively the first injection jets are respectively divided into the first subset, the second subset and the third subsets based on the first injection jets and the second injection jets. The second injection jets are not divided into any more subsets, such that the second injection jets each form a fourth subset in the combustion chamber when viewed separately. Since the respective first injection jet is divided into the first subset, the second subset and the third subsets by means of the jet splitter contour, such that the first combustion front, the second combustion front and the third combustion front are formed, and the respective second injection jet injects a fourth subset, such that the fourth subset forms a fourth combustion front, the method according to the invention is a combustion method formed as a four-front combustion method according to which the internal combustion engine preferably formed as a reciprocating piston engine is operated in its fired operation. In the fired operation, a fuel-air mixture is formed in the combustion chamber by means of the four subsets together, the mixture being combusted, such that, in the fired operation, combustion processes proceed in the combustion chamber. Advantageously, the first injection jets from the first injection openings are used in order to form the first, second and third combustion front, such that a fourth combustion front can be formed with the second injection jets, whereby a further improved combustion is achieved and the combustion air spatially distributed in the combustion chamber is utilized in a further optimized manner.

Preferably, the internal combustion engine is a self-igniting internal combustion engine, such that the internal combustion engine is preferably a diesel engine. The respective injection jet and thus the respective subset or subsets is formed by means of an in particular liquid fuel, in particular a liquid diesel fuel, such that the fuel is injected directly into the combustion chamber by means of the injector by forming the injection jets, in particular within a respective work cycle of the internal combustion engine and the four subsets each combust in a diffusion combustion. Preferably, the internal combustion engine is formed as a four-stroke engine, such that the respective work cycle has exactly 720 degrees of crank angle. The fuel-air mixture previously mentioned thus comprises the fuel which, in particular within the respective work cycle, is injected directly into the combustion chamber by means of the injector. Furthermore, the fuel-air mixture comprises combustion air which flows into or is led into the combustion chamber. By means of the method according to the invention, a particularly advantageous and in particular effective combustion can be achieved by an optimized utilization of the combustion air present in the combustion chamber, such that soot emissions emerging by means of the diffusion combustion of the internal combustion engine formed as a diesel engine can be kept to a particularly low level. Moreover, a particularly efficient and thus fuel-efficient operation of the internal combustion engine can be depicted.

The injector has first injection openings, which are, for example, first injection bores, or are also referred to as first injection bores. The first injection jets are caused by the first injection openings, for example. In other words, a first part of the fuel to be injected into the combustion chamber within the respective work cycle, for example, is injected through the first injection openings and thus injected directly into the combustion chamber, whereby the first injection jets are injected into the combustion chamber. Furthermore, the injector has second injection openings provided in addition to the first injection openings, for example, which are second injection bores, for example, or are also referred to as second injection bores. The second injection jets are caused by means of the second injection openings. Thus, a second part of the fuel to be injected directly into the combustion chamber within the respective work cycle by means of the injector, for example, is injected by the second injection openings and thus injected directly into the combustion chamber via the second injection openings, whereby the second injection jets emerge or are injected directly into the combustion chamber. The first injection openings and the second injection openings here differ, for example, in terms of the respective geometries and/or alignments and/or arrangement in the injector, such that, by means of the first injection openings, the respective first jet breakup and, by means of the second injection openings, the second jet breakup different from the respective first jet breakup, are caused or generated. In particular, the first injection openings and the second injection openings are formed to cause different injection impulses of the injection jets. In other words, for example, the first injection jets and the second injection jets differ from one another in terms of their injection impulses, such that the respective first injection jet, for example, has a first injection impulse, and the respective second injection jet has a second injection impulse different from the respective first injection impulse. In particular, with different jet breakup, different impulses can be set. Here, a small jet breakup has a higher impulse than a large jet breakup. In doing so, a particularly advantageous distribution of the injected fuel can be ensured.

The first injection jets are injected directly into the combustion chamber in the shape of a star at least in relation to one another or at least when viewed one below the other.

In a further design of the invention, the jet breakup of the first injection jets is smaller than the jet breakup of the second injection jets. This means, for example, that the first injection jets are narrower along a respective first longitudinal central axis in their injection direction of the respective first injection jets than the respective second injection jets along a respective second longitudinal central axis in their injection direction of the respective second injection jets. In other words, the second injection jets, for example, are thus bushier or more bulbous with a thick jet lobe than the first injection jets and have a greater jet breakup with a further expansion transversely to its second longitudinal central axis than the first injection jets with a thin jet lobe, which has a smaller jet breakup with a smaller expansion transversely to its first longitudinal central axis. Thus, a particularly advantageous utilization of the combustion air present in the combustion chamber can be achieved. Advantageously, the second injection jets clearly reach less far into the combustion chamber than the first injection jets, such that the second injection jets expand in the close region of the injector, whereby the utilization of the combustion air present in the combustion chamber is further improved.

With the respective jet breakup, a respective angle is described which the respective injection jet assumes in its spatial expansion starting from the injector. In particular, the jet breakup, along with the injection pressure, can be influenced by a geometrical shape of the injection openings. Furthermore, roundness and conicity of the injection openings have an influence on the jet breakup.

In order to achieve a particularly efficient and thus fuel-efficient operation, it is provided in a further design of the invention that the first injection jets reach further into the combustion chamber than the respective second injection jets. In doing so, a particularly advantageous combustion can be achieved. Reaching further into the combustion chamber is to be understood as meaning that, starting from the injector, the first injection jets penetrate deeper into the combustion chamber than the second injection jets, such that the first injection jets, for example, extend further away from the injector than the second injector jets. Advantageously, the combustion air in the combustion chamber can be mixed with the second injection jets in the region around the injector, such that combustion air not consumed by the third combustion fronts in the direction of the injector can be mixed with fuel from the second injection jets and forms the fourth combustion fronts in the close region of the injector, whereby a further improved combustion is achieved and the combustion air spatially distributed in the combustion chamber is utilized in a further optimized manner.

A further embodiment is characterised in that the first jet breakups are identical among one another. Alternatively or additionally, it is provided that the second jet breakups are identical among one another. In doing so, the fuel can be injected particularly advantageously into the combustion chamber, such that a particularly optimized combustion can be depicted.

In a particularly advantageous embodiment of the invention, the second injection jets are injected into the combustion in a star shape at least in relation to one another or at least when seen one below the other. In doing so, a particularly optimized combustion can be achieved.

It has been shown to be particularly advantageous when the first injection jets and the second injection jets are injected simultaneously into the combustion chamber and in a star shape in relation to one another or when seen one below the other. In doing so, a particularly optimized combustion can be achieved.

It has been shown to be particularly advantageous when the first injection jets and the second injection jets alternatingly follow on from one another in the peripheral direction of the piston when injecting the injection jets. This means that exactly one second injection jet is arranged between respectively two adjacent first injection jets or exactly one first injection jet is arranged between two second injection jets adjacent in the peripheral direction. Advantageously, the third combustion front and the fourth combustion front form in the gaps between first injection jets, such that no or only a minimal overlap of the first and the second injection jets takes place, whereby a further improved combustion is achieved and the combustion air spatially distributed in the combustion chamber is utilized in a further optimized manner.

It has been shown to be particularly advantageous for a fuel-efficient and low emission operation when the first injection jets are injected with a first jet cone angle in a range of from 130 degrees inclusive to 160 degrees inclusive. In particular, the first jet cone angle is 150 degrees.

In order to be able to achieve a particularly optimized utilization of the combustion air present in the combustion chamber, it is provided in a further design of the invention that the second injection jets are injected with a second injection cone angle in a range of from 100 degrees inclusive to 125 degrees inclusive. Here, it has been shown to be particularly advantageous when the second jet cone angle is 120 degrees.

Advantageously, the different jet cone angles for the first injection jets and the second injection jets respectively enable a different tilting of the respective injection jets in relation to the cylinder head or piston, such that the combustion air of different regions is mixed with injected fuel in the combustion chamber, whereby a further improved utilization of the present combustion air is carried out in the combustion chamber and the combustion of the injected fuel is further improved in the combustion chamber.

In order to develop an internal combustion engine of the kind herein in such a way that a particularly advantageous and in particular optimized combustion can be achieved, it is provided according to the invention that first deflection means are arranged in the piston stage by means of which the injection jets can be divided into third subsets and/or second deflection means are arranged which deflect the third subset from the peripheral direction in the radial direction inwardly and, in particular, in the direction of the piston hollow. Furthermore, the first injection jets are formed with respective first jet breakups, and, by means of the injector, several second injection jets provided in addition to the first injection jets with respective second jet breakups can be simultaneously injected directly into the combustion chamber for the combustion process. Advantages and advantageous designs of the method according to the invention are to be seen as advantages and advantageous designs of the internal combustion engine according to the invention and vice versa.

Further advantages, features and details of the invention emerge from the description below of a preferred exemplary embodiment and by means of the drawings. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and/or shown only in the figures can not only be used in the respectively specified combination, but rather also in other combinations or individually, without leaving the scope of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

In the figures, the same or functionally identical elements are provided with the same reference numerals.

In a schematic sectional view,FIG. 1sectionally shows an internal combustion engine10formed as a stroke piston engine for a motor vehicle, such as a passenger vehicle or a commercial vehicle, for example. Here, the motor vehicle can be driven by means of the internal combustion engine10. The internal combustion engine10has at least one cylinder12, the combustion chamber14of which is delimited in the radial direction of the cylinder12by a cylinder wall16. The radial direction of the cylinder12is illustrated inFIG. 1by a double arrow18. The cylinder wall16is formed, for example, by a cylinder housing, formed in particular as a cylinder crank housing, of the internal combustion engine10. The combustion chamber14is delimited in the axial direction of the cylinder12by a piston20of the internal combustion engine10that can be received translationally moveably in the cylinder12. In particular, the cylinder wall16forms a track22, wherein the piston20can be supported on the track22in its radial direction and thus in the radial direction of the cylinder12. The axial direction of the cylinder12coincides with the axial direction of the piston20, wherein the radial direction of the cylinder12coincides with the radial direction of the piston20.

The combustion chamber14is delimited in the axial direction of the cylinder12opposite the piston12by a combustion chamber roof26of the internal combustion engine10. The combustion chamber roof26is formed, for example, by a cylinder head28of the internal combustion engine10. The cylinder head28is, for example, a component formed separately from the cylinder housing and connected to the cylinder housing. Since the piston20is received translationally moveably in the cylinder12, the piston20can be moved forwards and backwards between an upper dead center and a lower dead center in the axial direction of the cylinder12in relation to the cylinder wall16, such that the piston20can be stroke adjusted.

The piston20has an annularly peripheral piston stage32which is arranged axially recessed in the piston20in comparison with an annularly peripheral piston crown32of the piston20and which merges into a piston hollow36, arranged axially recessed in the piston20in relation to the piston stage32, of the preferably integrally formed piston20via an annularly peripheral jet splitter contour34of the piston20. The respective feature of the piston stage32being axially recessed in comparison with the piston crown32or that the piston hollow36is arranged to be axially recessed in relation to the piston crown32is to be understood to mean that the piston stage32is recessed in comparison with the piston crown30in the axial direction of the piston20and thus in the axial direction of the cylinder12or set back towards the piston hollow36or that the piston hollow36is set back in the axial direction of the piston20and thus in the axial direction of the cylinder12away from the combustion chamber roof26in comparison with the piston stage32.

Furthermore, at least or exactly one injector38of the internal combustion engine10is allocated to the combustion chamber14. The injector38is held on the cylinder head28and here arranged at least partially, in particular at least substantially or completely, in the cylinder head28.

The piston20is coupled, for example flexibly, with an output shaft, formed as a crankshaft, of the internal combustion engine10. The crankshaft can be rotated around an axis of rotation in relation to the cylinder housing. As a result of the flexible coupling of the piston20with the crankshaft, the translational movements of the piston20in the cylinder12are converted into a rotational movement of the crankshaft around its axis of rotation, whereby the crankshaft rotates around its axis of rotation in relation to the cylinder housing. Here, the internal combustion engine10is formed as a four-stroke engine, such that a respective work cycle of the internal combustion engine10comprises 720 degrees of crank angle, i.e., exactly two complete rotations of the crankshaft. Within the respective work cycle, at least one combustion process or several combustion processes proceed in the combustion chamber14, as part of which a fuel-air mixture is combusted. In doing so, the piston20is driven, whereby the crankshaft is driven and thus rotated around its axis of rotation in relation to the cylinder housing. As is explained in more detail below, the fuel-air mixture comprises air which flows into or is introduced into the combustion chamber14. Moreover, the fuel-air mixture comprises a fuel which is injected within the respective work cycle directly into the combustion chamber14by means of the injector38. The fuel is preferably a liquid fuel. Furthermore, additionally returned exhaust gas can be present in the combustion chamber14if an exhaust gas return is provided. Preferably, the internal combustion engine10is formed as a self-igniting internal combustion engine, in particular as a diesel engine, such that the fuel is a diesel fuel. A method for operating the internal combustion engine10is described below, wherein the internal combustion engine10is operated in a fired operation during the method or by means of the method, during which the at least or preferably exactly one combustion process proceeds in the combustion chamber14within the respective work cycle. Thus, the method is a combustion method according to which the internal combustion engine10is operated in its fired operation. In particular, the internal combustion engine10is operated in a self-igniting operation during the method or by means of the method, as part of which the fuel-air mixture or a fuel-air-exhaust gas mixture is ignited in an independently sparking manner, i.e., without using an external ignition device, such as a spark plug, for example.

Within the respective work cycle for the respective combustion process, several first injection jets40are simultaneously injected by means of the injector38directly into the combustion chamber14in the shape of a star along their respective longitudinal central axes41, which can be seen particularly well when seen together withFIG. 2. Here, inFIGS. 1 and 2, the first injection jets40are shown when impinging on the jet splitter contour34. In the further course of the injection, in particular during the first expansion of the injection jets into the combustion chamber14, the respective first injection jet40is divided by means of the jet splitter contour34into a first subset42entering into the piston hollow36(depicted as an arrow), into a second subset44entering into a region B between the piston crown30and the combustion chamber roof26via the piston stage32(depicted as an arrow) and into third subsets46(depicted as an arrow) (FIG. 2). The at least or exactly two third subsets46expand starting from the respective first injection jet40on both sides in the peripheral direction of the piston20in opposite directions along the piston stage32and collide between two adjacent injection jets40and are thus radially, i.e., in the radial direction of the piston20, deflected inwardly in the direction of the injector38. Here, the peripheral direction of the piston20is illustrated inFIG. 2by a double arrow48, wherein the peripheral direction runs around the axial direction, for example.

The respective injection jet40and thus the subsets42,44and46are formed by respective parts or fuel parts of the fuel, which is injected within the respective work cycle by means of the injector38directly into the combustion chamber14. Thus, the fuel is injected directly into the combustion chamber14within the respective work cycle by means of the injector38by forming the injection jets40. The first subset42forms a first combustion front, and the second subset44forms a second combustion front. The respectively third subsets46deflected inwardly together form a third combustion front radially outwards into a gap50between the injection jets40or between two adjacent injection jets40. A resulting current58(depicted as an arrow) formed from a swirl52(depicted as an arrow), a crushing gap current54(depicted as an arrow) and a jet current56(depicted as an arrow) deflect the injection jets40up-jet or upstream of the jet splitter contour34in the direction of the piston20, such that the injection jets40furthermore impinge on the piston20with a piston20moving away from the cylinder head28in the expansion stroke substantially further into the region of the jet splitter contour34.

In order to now be able to achieve a particularly effective combustion by optimally utilizing the combustion air present in the combustion chamber14, first deflection means62and, alternatively to or in combination with the first deflection means, second deflection means62′ are arranged in the piston stage32, in particular in its stage chamber60. Here, the first deflection means62divide the injection jets40striking the jet splitter contour34into third subsets46or, with the division into the third subsets46, support them. The second deflection means62′ can deflect the respective third subset46in the radial direction inwardly. It can be seen fromFIG. 2that the respective first deflection means62and the second deflection means62′ are formed as a jet splitter or a nose. Moreover, it can be seen particularly well fromFIG. 1andFIG. 2that the piston stage32has a stage wall64, also referred to as a side wall, by means of which the piston stage32or the stage chamber60is delimited outwardly in the radial direction of the piston20. Furthermore, the piston stage32has a stage floor66, also referred to as the floor, by means of which the piston stage32or the stage chamber60is delimited in the axial direction of the piston20downwardly in opposition to the cylinder head28. The respective nose here projects in the radial direction of the piston20outwardly from the stage wall64and in the axial direction of the piston20on the stage floor66. Thus, the respective deflection means62and62′ protrude from the stage wall64in the radial direction inwardly towards the stage chamber60and are connected to the stage floor66. Furthermore, the first deflection means62are provided at an impingement point of the injection jets62on the jet splitter contour34in the piston stage32in the stage chamber60, and the second deflection means62′ are provided substantially starting from the injector38respectively centrally between two adjacent first injection jets40in the piston stage32in the stage chamber60.

Moreover, the first injection jets40are injected directly into the combustion chamber14in the form of jet cones with a respective first jet breakup α1. To do so, the injector38, for example, has first injection openings not described in more detail, via which the first injection jets40are injected directly into the combustion chamber14. Thus, the first injection jets40are caused by means of the first injection openings, such that the first injection openings cause the respective first jet breakups α1.

Moreover, several second injection jets68provided in addition to the first injection jets40are simultaneously injected directly into the combustion chamber14with a respective second jet breakup α2by means of the injector38for the combustion process or within the respective work cycle. Here, the respective first jet breakups α1differ from the respective second jet breakups α2. The first injection jets40point along a respective first longitudinal central axis41in their injection direction of the respective first injection jets, are narrower or have a further expansion than the respective second injection jets68along a respective second longitudinal axis69in their injection direction of the respective second injection jets68. In other words, the second injection jets68, for example, are thus bushier or more bulbous with a thick jet lobe than the first injection jets40and have a greater jet breakup α2with a further expansion transversely to its second longitudinal central axis69than the first injection jets40with a thin jet lobe, which has a smaller jet expansion transverse to its first longitudinal central axis41. For this, the injector38has, for example, second injection openings not referred to in more detail provided in addition to the first injection openings, by means of which or via which the second injection jets68are injected directly into the combustion chamber14. Thus, the second injection openings each cause a second injection jet68which respectively forms an injection jet68with a respective second jet cone angle α2. Here, the second injection jets68are flushed by the injector38in the direction of the piston36as a fourth subset based on an axial direction of the piston20in a jet cone angle β2different from the first injection jets40. The fourth subsets formed by the respective second injection jets68each form a fourth combustion front.

For example, a first part of the fuel, which is injected directly into the combustion chamber14within the respective work cycle by means of the injector38, is injected through the first injection openings and thus directly into the combustion chamber14via the first injection openings. The first part of the fuel thus forms the first injection jets40. Furthermore, for example, a second part of the fuel, which is injected directly into the combustion chamber14by means of the injector38within the respective work cycle, is injected through the second injection openings and thus injected directly into the combustion chamber14via the second injection openings. Here, the second part of the fuel forms the respective second injection jets68. The first part and the second part form, for example, the fuel in total, which is injected directly into the combustion chamber14within the work cycle by means of the injector38in total. If further injections of first injection jets40and second injection jets68are injected into the combustion chamber14within a work cycle, all first and second parts form the sum of the fuel that is injected into the combustion chamber14.

As can be seen particularly well fromFIG. 2, the first injection jets40are injected into the combustion chamber14in the shape of a star when seen one below the other or in relation to one another. The second injection jets68are also injected into the combustion chamber14in the shape of a star when seen one below the other or in relation to one another. Moreover, it is provided that the first injection jets40and the second injection jets68are simultaneously injected into the combustion chamber14in the shape of a star in relation to one another.

Moreover, the first injection jets40are longer than the second injection jets68. In particular, the first injection jets40reach further into the combustion chamber14than the second injection jets68. Furthermore, the second injection jets68are wider than the first injection jets40and are thus bushier or more bulbous. The first jet breakups α1are the same and the second jet breakups α2are the same, such that the respective first jet breakup α1differs from the respective second jet breakup α2.

It has been shown to be particularly advantageous when the first injection jets40with a first jet cone angle α1are injected into the combustion chamber14. The jet cone angle β1includes the angle which the first injection jets40enclose. The respective first jet cone angle β1ranges from 130 degrees inclusive to 160 degrees inclusive and can be, in particular, 150 degrees, while, for example, the respective second jet cone angle β1ranges from 100 degrees inclusive to 125 degrees inclusive and can be, in particular, 120 degrees.

Moreover, it is provided that, when injecting the first injection jets40and the second injection jets68, alternatingly follow on from one another in the peripheral direction of the piston20and thus the cylinder12.

It can be seen particularly well inFIG. 1that the respective first injection jet40is a narrow jet with high impulse, high K-factor and high he-rounding. The respective second injection jet68is a bushy jet with low impulse, low K-factor, i.e., low conicity and low he-rounding.

The respective injection jet40or68is formed by a respective fuel mass, also referred to as the injection mass, of the fuel. Here, the distribution of the injection masses between the injection jets40and68is conceivable in such a way that it corresponds to the mass of the combustion air available in this chamber, in particular in the chamber in which the respective injection jets40and68expand. Thus, a particularly advantageous combustion can be ensured.

LIST OF REFERENCE CHARACTERS