INTERNAL COMBUSTION ENGINE WITH INTAKE MANIFOLD INJECTION, IN PARTICULAR HYDROGEN COMBUSTION ENGINE WITH INTAKE INJECTION

Abstract

The invention relates to an internal combustion engine with intake manifold injection, comprising at least two combustion chambers, at least one central rail for supplying fuel for the intake manifold injection, and at least one air distributor for supplying air to the individual combustion chambers, characterized in that the central rail is attached to the air distributor, or the central rail and the air distributor are formed as an integral component.

Claims

1. Internal combustion engine with intake manifold injection, comprising at least two combustion chambers (2), at least one central rail (10) for supplying fuel for the intake manifold injection, and at least one air distributor (30) for supplying air to the individual combustion chambers (2), wherein the central rail (10) is attached to the air distributor (30), or the central rail (10) and the air distributor (30) are formed as an integral component.

2. Internal combustion engine according to claim 1, wherein one or more fuel injectors (40) are at least partially installed in the central rail (10), and a component or region of the injector 40 located outside the central rail (10) preferably comprises actuating components of the injector (40), in particular electrical components for injector actuation.

3. Internal combustion engine according to claim 2, wherein the longitudinal axis of an injector (40) installed in the central rail (10) is perpendicular to the longitudinal axis of the central rail (10).

4. Internal combustion engine according to claim 2, wherein the entire injector (40) or at least the component or region of the injector (40) located outside the central rail (10) can be dismantled and removed from outside the central rail (10), and this component or region of the injector 40 preferably comprises all actuating components of the injector (40), in particular all electrical components or electrical parts for injector actuation.

5. Internal combustion engine according to claim 4, wherein a component or region of the injector (40) or the entire injector (40) is fixed by a fixing means accessible from outside on the central rail (10), in particular a retaining claw (45) screwed to the central rail (10), and only the fixing means accessible from the outside has to be mounted or released for installation and/or removal.

6. Internal combustion engine according to claim 1, wherein the at least one injector (40) comprises, on the circumferential side, an annular groove (42) located inside the central rail (10) with one or more radial bores for fluid connection between the central rail (10) and the injector (40), and preferably the injector part (41) which can be separated from the central rail (10) from the outside comprises the annular groove (42).

7. Internal combustion engine according to claim 1, wherein the central rail (10) and the air distributor (30) are configured to perform single-point or multi-point intake manifold injection.

8. Internal combustion engine according to claim 1, wherein the central rail (10) extends at least partially through the air distributor (30), in particular extends through the inner hollow volume of the air distributor (30).

9. Internal combustion engine according to claim 8, wherein at least one duct (43) formed for fuel supply, in particular the injector nozzle (43) extending through the air distributor (30), preferably extends into the inlet duct (52a) of the combustion chamber (2) to be supplied with fuel.

10. Internal combustion engine according to claim 1, wherein the central rail (10) is configured in one or more parts, in particular, in the longitudinal direction, a plurality of rail section parts (10a, 10b, 10c) which can be assembled.

11. Internal combustion engine according to claim 10, wherein at least one rail section part (10c) comprises the fuel connection (12) of the central rail (10) upstream in the direction of the primary fuel tank, and the rail section part (10c) comprising the fuel connection (12) is preferably mountable with different orientation of the fuel connection (12) to the remaining section parts of the central rail (10).

12. Internal combustion engine according to claim 1, wherein a control system is provided and configured to carry out sequential and preferably cylinder-specific fuel injection.

13. Internal combustion engine according to claim 1, wherein a gaseous fuel is used as primary fuel, in particular the internal combustion engine is a hydrogen combustion engine.

14. Internal combustion engine according to claim 3, wherein the entire injector (40) or at least the component or region of the injector (40) located outside the central rail (10) can be dismantled and removed from outside the central rail (10), and this component or region of the injector 40 preferably comprises all actuating components of the injector (40), in particular all electrical components or electrical parts for injector actuation.

15. Internal combustion engine according to claim 14, wherein a component or region of the injector (40) or the entire injector (40) is fixed by a fixing means accessible from outside on the central rail (10), in particular a retaining claw (45) screwed to the central rail (10), and only the fixing means accessible from the outside has to be mounted or released for installation and/or removal.

16. Internal combustion engine according to claim 15, wherein the at least one injector (40) comprises, on the circumferential side, an annular groove (42) located inside the central rail (10) with one or more radial bores for fluid connection between the central rail (10) and the injector (40), and preferably the injector part (41) which can be separated from the central rail (10) from the outside comprises the annular groove (42).

17. Internal combustion engine according to claim 14, wherein the at least one injector (40) comprises, on the circumferential side, an annular groove (42) located inside the central rail (10) with one or more radial bores for fluid connection between the central rail (10) and the injector (40), and preferably the injector part (41) which can be separated from the central rail (10) from the outside comprises the annular groove (42).

18. Internal combustion engine according to claim 5, wherein the at least one injector (40) comprises, on the circumferential side, an annular groove (42) located inside the central rail (10) with one or more radial bores for fluid connection between the central rail (10) and the injector (40), and preferably the injector part (41) which can be separated from the central rail (10) from the outside comprises the annular groove (42).

19. Internal combustion engine according to claim 4, wherein the at least one injector (40) comprises, on the circumferential side, an annular groove (42) located inside the central rail (10) with one or more radial bores for fluid connection between the central rail (10) and the injector (40), and preferably the injector part (41) which can be separated from the central rail (10) from the outside comprises the annular groove (42).

20. Internal combustion engine according to claim 3, wherein the at least one injector (40) comprises, on the circumferential side, an annular groove (42) located inside the central rail (10) with one or more radial bores for fluid connection between the central rail (10) and the injector (40), and preferably the injector part (41) which can be separated from the central rail (10) from the outside comprises the annular groove (42).

Description

[0028] Further advantages and features of the invention will be explained in more detail below with reference to an exemplary embodiment shown in the figures. The figures show in:

[0029] FIG. 1: a schematic representation of an internal combustion engine according to the invention,

[0030] FIG. 2: a view of the air distributor with the central rail attached and the injectors mounted,

[0031] FIG. 3: the air distributor of FIG. 2 in an individual representation with a view diametrically opposed to the mounting surface of the air distributor for mounting on the internal combustion engine,

[0032] FIG. 4: a representation of the air manifold of FIG. 3 with the central rail attached and the injectors partially mounted,

[0033] FIG. 5: a sectional view of the combustion engine according to the invention with attached air distributor, central rotor and injectors,

[0034] FIG. 6: an enlarged detailed view of a section of FIG. 5,

[0035] FIG. 7: a further enlarged representation of the detailed section of FIG. 6, and

[0036] FIG. 8: individual illustrations of an injector with fixing elements.

[0037] FIG. 1 shows a schematic representation of the internal combustion engine according to the invention. FIGS. 2 and FIGS. 4 to 7 show a specific example of the components central rail 10, air distributor 30 and injectors 40. FIG. 3 is limited to a specific example of an air distributor 30. First, however, the principle of the invention will be described in more detail on the basis of the schematic representation in FIG. 1. The internal combustion engine shown there comprises at least two combustion chambers 2; four combustion chambers 2 are shown. An internal combustion engine according to the invention comprises at least two combustion chambers 2 which have a common air distributor 30 and whose fuel is supplied via a jointly used rail or central rail 10 by means of intake manifold injection. (Preferably, all combustion chambers 2 arranged along a cylinder bank 1 have a common air distributor 30 and a common central rail 10.

[0038] The core of the invention is that the central rail 10 is located in the immediate vicinity of the air distributor 30 and is preferably mounted directly on the air distributor 30, e.g. by screw connections and/or by galvanic bonding. Particularly preferably, the two functional elements air distributor 30 and central rail 10 can also be manufactured as an integral component. In the embodiment according to the invention, the injectors 40 are installed in or attached to the central rail 10 in such a way that there is a direct fuel supply from the central rail 10 into an injector 40, i.e. that there is a direct fluid connection without a line pipe and without penetration of a further component between rail 10 and injector 40. In the illustration according to FIG. 1, the exhaust gas path 14 is still indicated. The exhaust gas enters the common exhaust manifold 3 via the exhaust ports 52b of the combustion chambers 2. The schematic representation of these exhaust ports 52b is limited to the cylinder head 52. Since it is not directly related to the invention, the suggestion of a design of the flow paths in the symbolized air distributor 30 and the symbolized exhaust manifold 10 has been omitted for the sake of clarity.

[0039] In the case of a combination of the two functional elements air distributor 30 and central rail 10 to form a one-piece component, which corresponds to a preferred embodiment, for example, a blank could be produced, preferably as a molded part or casting, which already comprises the internal cavities, internal connections, internal separations and, above these, the other recesses including the external connections required for an air distributor 30 and for a central rail 10, wherein the latter, after completion of an e.g. cast blank, can possibly only be present at such a production stage which requires reworking. Cast blank, for example, may only be present at such a manufacturing stage that requires post-processing. Finishing, e.g. reworking of recesses and surfaces requiring particularly high dimensional accuracy and/or particularly high surface quality, cutting of threads, etc. until completion, would then be carried out on this blank or molded part. Insofar as the two functional elements air distributor 30 and central rail 10 are designed as separate components, unlike in the preferred embodiment, additional precautions would have to be taken in order to achieve their functionally correct connection. This relates to the finishing of certain surfaces and the sealing of certain joints between these two components. In the case of an integral component, such measures are not required for the transition area between the air distributor 30 and the central rail 10.

[0040] The principle of intake manifold injection can be realized by generating the fuel-air mixture in the air manifold 30 due to the nature of the parts, i.e. the injector or injectors 40 inject the fuel directly into the air manifold 30. Such a principle is referred to as single-point intake manifold injection. In this case, the injector 40 extends through the two separate abutting walls of the central rail 10 and the air distributor 30, or through the common partition of these two functional elements, and the injector nozzle 30 terminates in the air distributor 30, wherein the meeting of the fuel and the air occurs in the air distributor 30. From there, the fuel-air mixture can enter the provided inlet ducts 52a of the combustion chambers 2.

[0041] In the principle of multi-point injection as prepared in the embodiment example of FIG. 3 and implemented in FIGS. 2 and 4, the fuel is injected by the injectors 40 directly into the respective cylinder head 52, in particular into the inlet port 52a provided there. For this purpose, the injector 40 must extend through the two separate abutting walls of the central rail 10 and the air distributor 30 or through the common partition wall of these two functional elements and preferably extend across the entire width of the air distributor 30 so that the injector nozzle 43 opens into the inlet port 52a already provided in the cylinder head 52, whereby the meeting of the fuel and the air only takes place in the immediate vicinity of the inlet valve or inlet valve pair.

[0042] FIG. 2 shows a bottom view of the air distributor 30 with attached central rail 10 and inserted fuel injectors 40. By means of the air distributor 30 and the central rail 10, a total of six combustion chambers 2 are supplied with a fuel-air mixture in the example shown. The air distributor 30 is attached to the cylinder head 52 of an internal combustion engine by means of the contact surface marked 31 (see FIG. 5); for each combustion chamber 2, at least two fastening screws 32 are provided for screwing to the cylinder head 52, which are passed through the sleeves 32a cast onto the air distributor 30. The injector nozzle 43 is fixed to the air distributor 30 by means of mounting screws 15. The individual fuel injectors 40 are installed in the central rail 10 from the side facing away from the air distributor 30 and in such a way that the section 41 of the injector 40 having a valve function is located at least partially within the central rail 10, the longitudinal section of the injector 40 which comprises the annular groove 42 serving to feed fuel into the injector 40 being located completely within the central rail 10 (see FIG. 6). As can be seen in the illustration, the injector nozzle 43 has a tubular shape which is carried through the volume of the air distributor 30. After assembly, the injector nozzle 43 opens into the respective inlet duct 52a of the combustion chamber 2 to be supplied, which can be seen in the sectional view of FIG. 5. Since a separate injector 40 is provided for each combustion chamber 2, and fuel is injected into the inlet port 52a, this is a multi-point intake manifold injection system. Above the mounted injectors 40 is the connection 35 with the contact surface 35a for the charge air supply line 13 to the air distributor 30.

[0043] The sectional view of FIG. 5 shows the close-up area of the inlet port 52a to a combustion chamber 2. It is a section angled along the roofed longitudinal axis of the combustion chamber 2 under consideration. The exposed section of the cylinder head 52 shows the inlet port 52a and other cavities, for example cooling chambers. Since the latter are not related to the invention, any description is omitted here. To the right of the cylinder head 52 is mounted the air distributor 30, the lower portion of which is exposed in the section shown. As expected, the two inner contours of the air path visible in the drawing plane show a tangent transition at the transition from the air distributor 30 into the inlet port 52a located in the cylinder head 52. The section is selected such that the imaginary longitudinal axis of the injector 40 is located on the section plane. In relation to the air flow path, the injector 40 is positioned in such a way that its imaginary longitudinal axis and thus the flow direction of the injected fuel enters the flow field of the air in an angular position that is as advantageous as possible in this respect, which makes it possible to expect or prove that there is already extensive mixing of fuel and air on the common residual running distance along the inlet channel 52a.

[0044] The invention is not limited to spark ignited internal combustion engines. The presence of a spark plug 56 is based only on the exemplary embodiment.

[0045] FIG. 6 shows an enlarged section of the already known section in the transition area from the central rail 10 to the air distributor 30. In the embodiment example, this is an injector 40 consisting of two assemblies which are mounted separately from one another and which, in the installed state including an opening 16 of the central rail 10, are located on a common longitudinal axis and form an injector 40. The component arranged on the right side is an injector valve 41, the outlet of which is located on the front side facing the air distributor 30. The injector nozzle 43 arranged on the left-hand side has a tubular shape, at the end section 43a of which facing the injector valve 41 there is an increased outer diameter and at this end it is equipped with a flange (see detailed views of the injector 40 in FIG. 8) and, provided with a seal 43b, is screwed directly onto the central rail 10.

[0046] A support plate 46 is welded to the end section 43a of an injector nozzle 43 which has the larger outer diameter. Bores 46a in the carrier plate 46 are used for bolting to the central rail 10. The bolts required for this purpose can be inserted through the threaded bores 46b provided on the accessible surface of the central rail 10 (see FIG. 4) and passed through the central rail 10 into the bores 46a of the carrier plate 46. Sealing elements 46c inserted between the central rail 10 and the support plate 46 ensure that the fuel gas stored inside the central rail 10 is sealed off from the environment.

[0047] A section of the injector 40 is provided with an annular groove 42 having radial bores distributed around its circumference, allowing fuel to pass from the annular groove 42 to the injector nozzle 43 via the injector valve 41. A fluid connection 19 with a large cross-sectional area exists between the annular groove 42 and the rail inner volume 18. Seals 47 on the outer circumference of the injector valve 41 serve to prevent fuel leakage to the surroundings.

[0048] On the side facing the central rail 10, the wall of the air distributor 30 comprises through openings 34 for the injectors 40. In the vicinity of these passage openings 34, the housing is reinforced so that instead of simple housing holes, there is a bushing area 34a in each case (see FIG. 3), which forms a large-surface contact with the injector 40 in its end section 43a of the increased outer diameter, which ensures centering of the injectors 40 and sealing of these passage openings 34. Preferably, the bushing region 34a should already be produced by casting the air distributor 30 in its raw form. The final production of such a bushing region 34a is preferably limited to a finishing operation, by means of which a corresponding dimensional accuracy of the recesses already present in the casting blank is ensured.

[0049] The injector valve 41 is integrated in the central rail 10 in such a way that the rail housing is even a component of the injector housing (cf. FIG. 7). In the embodiment shown here, the section of the injector valve 41 with the electrical connections and thus the electrical part of the injector 40 is located outside the air distributor 30, where an air/gas mixture can in principle be present. Although a high excess of air would then be present in the air distributor 30, in the case of a hydrogen engine this spatial separation of the electrical system creates a safety advantage, since a hydrogen-air mixture is ignitable even with a very high excess of air and a very small energy input is already sufficient for ignition. The assembly and disassembly of the injector 40 is possible from the outside, in that only one fixing element needs to be screwed on or unscrewed (cf. FIGS. 4 and 8). The fixing element is formed as a retaining claw 45 which can be screwed to the rail housing. A half-opening of the retaining claw 45 can be inserted into a radial external groove 48 of the injector housing, whereby the injector 41 can be fixed in a precisely defined position on the central rail 10.

[0050] A rail pressure sensor 50 (see FIG. 5) can be inserted into the central rail in the area of the fuel connection 12 through a hole 50a from the outside.

[0051] The idea according to the invention can in principle be used for all internal combustion engines of the topologies commonly used today, including, for example, in-line, V- and flat engines. It can also be used for compression-ignition and spark-ignition internal combustion engines. The same applies to 2-stroke, 4-stroke, 2-valve, 4 valve engines with or without supercharging; engines with or without EGR. Also, the application can used equally be applied to internal combustion engines running on liquid or gaseous fuel independent of the type of fuel. Use is also possible for stationary and mobile engines, i.e. on-road, off-road, maritime, offshore, etc. All designations listed in this section are to be understood as examples with the description not necessarily being exhaustive, and therefore the invention and accordingly the following patent claims are by no means limited to the engine configurations mentioned here.

[0052] The advantages of the invention will be briefly summarized again below: [0053] Elimination of numerous pipes in which pressurized fuel is guided from the rail 10 to the injectors 40. This reduces the amount of material and production efforts required for the components to be assembled, and thus reduces the amount of assembly required. Reducing the overall length of exposed high-pressure lines reduces the risk of damage and the secondary risks associated with such damage. [0054] There is a much better match between the measured rail pressure and the actual injection pressure in the intake manifold or intake port 52a; pressure losses over line lengths are reduced and/or running times for pressure fluctuations are shortened. [0055] The structure according to the invention favors a compact design of the internal combustion engine, in particular the structure enables [0056] good accessibility and convenient disassembly/assembly of the injectors 40 or at least the injector valves 41. [0057] simple guiding of the cables for powering the injectors 40 and for signal forwarding from sensors for measuring variables on or in the central rail 10 and the air distributor 30. [0058] A separation between the electrical section and the fuel section of the injector 40 is inherent. [0059] A preferred embodiment provides for the use of an integral component for the functions of the central rail 10 and those of the air distributor 30, the blank of which is preferably produced as a casting or molded part. The blank already includes all the necessary internal cavities, internal connections and the at least prepared external connections that are ultimately required to fulfill the functions of the air distributor 30 and the central rail 10. This measure eliminates the need for separate manufacture of a further comparatively costly casting. This eliminates the need for certain equipment for fasteners and for connecting and sealing certain fluid connections. It should be emphasized that these are those fittings which involve reworking of the casting and the mounting of additional components.

[0060] Secondary Advantages

[0061] It is well known that such pipelines have certain tolerances because bends have to be made during their manufacture. Due to such tolerances and the fact that several pipe connections have to be made when assembling an internal combustion engine, the assembly effort is not inconsiderable. Added to this is the mounting of various fixing elements that are required to limit the exposed pipe widths, since otherwise the vibration of the operated internal combustion engine can set the pipes into correspondingly pronounced oscillations. This is also advantageous because in certain applications the internal combustion engine is subjected to strong vibration, shock and impact loads, for example when it serves as the primary drive of a mobile machine.

[0062] If there are correspondingly high safety requirements or if the leakage of fuel would be correspondingly dangerous, for example because it is a gaseous fuel, the corresponding pipelines and connections would have to be configured correspondingly more safely and thus more elaborately, e.g. by using double-walled pipes, etc.

LIST OF REFERENCE CHARACTERS

[0063] Cylinder bank 1 [0064] Combustion chamber 2 [0065] Exhaust manifold 3 [0066] Central rail 10 [0067] Rail section parts 10a, 10b, 10c [0068] Fuel connection 12 [0069] Charge air supply line 13 [0070] Exhaust gas 14 [0071] Mounting screw 15 [0072] Opening in the rail 16 [0073] Rail internal volume 18 [0074] Fluid connection 19 [0075] Air distributor 30 [0076] Contact surface air distributor 31 [0077] Mounting screws 32 [0078] Sleeves for fixing screws 32a [0079] Passage openings 34 [0080] Socket area 34a [0081] Seal 34b [0082] Connection for charge air supply 35 [0083] Contact area 35a [0084] Injector 40 [0085] Injector valve 41 [0086] Annular groove 42 [0087] Injector nozzle 43 [0088] End section 43a [0089] Annular groove for seal 43b [0090] Fixation element 45 [0091] Carrier plate 46 [0092] Bores 46a [0093] Threaded hole 46b [0094] Sealing elements 46c [0095] Seals 47 [0096] Outside groove 48 [0097] Rail pressure sensor 50 [0098] Borehole 50a [0099] Engine block 51 [0100] Cylinder head 52 [0101] Inlet duct 52a [0102] Outlet duct 52b [0103] Liner 53 [0104] Piston 54 [0105] Cylinder head cover 55 [0106] Spark plug 56