INTERNAL COMBUSTION ENGINE

Abstract

An internal combustion engine according to the invention comprises at least two engine blocks which are coupled to one another and each of which includes at least two cylinders, each cylinder being connected to a common drive shaft via a transmission and a clutch. If there is a problem with one engine block, same can be disconnected from the drive shaft so that the engine can continue to operate by means of the other engine block.

Claims

1. An internal combustion engine, comprising at least two engine blocks which are coupled to one another and each of which includes at least one, preferably two, cylinders, each cylinder being connected to a common drive shaft via a transmission and a clutch.

2. The internal combustion engine according to claim 1, wherein the two engine blocks are designed in a V-shape such that the cylinder heads are arranged in a V-shape and that the drive shaft is arranged in the region of the V-clearance between the cylinder heads.

3. The internal combustion engine according to claim 1, wherein each engine block comprises a crankshaft.

4. The internal combustion engine according to claim 1, wherein the clutches are adapted such that they allow for coupling the (respective) crankshaft to the drive shaft only in one single angular position.

5. The internal combustion engine according to claim 1, wherein the clutches are designed as claw clutches.

6. The internal combustion engine according to claim 1, wherein the engine comprises a bottom-mounted camshaft.

7. The internal combustion engine according to claim 6, wherein a means for decoupling rocker arms and tappets is provided such as to allow for switching off cylinders.

8. The internal combustion engine according to claim 2, wherein a water cooling means for cooling the cylinder heads is provided, wherein the drive shaft has at least one centrifugal fan, which is also adapted for additionally cooling the cylinders, arranged thereon.

9. The internal combustion engine according to claim 1, wherein the engine blocks each comprise at least four, six or more cylinders.

10. The internal combustion engine according to claim 1, wherein the internal combustion engine also comprises an electric drive, thus being adapted as a hybrid drive.

11. The internal combustion engine according to claim 1, wherein operating condition sensors for detecting the operating conditions of the engine blocks are provided.

12. The internal combustion engine according to claim 11, wherein the operating condition sensors generate a signal or are coupled to a controller which disconnects one engine block that is not running or only partially running from the drive shaft by decoupling it.

13. An intermediate plate for connecting at least two engine blocks of an engine, wherein the intermediate plate is a plate-shaped component, wherein the intermediate plate also comprises at least one bearing borehole for receiving at least one bearing of a crankshaft.

14. The intermediate plate according to claim 13, wherein the bearing borehole is adapted for coaxially bearing two crankshafts.

15. The intermediate plate according to claim 13, wherein the intermediate plate comprises two sealing faces adapted for respectively sealing one side of the engine blocks.

16. The intermediate plate according to claim 13, wherein the intermediate plate is adapted for receiving the gear transmissions and/or the camshaft drives.

17. The internal combustion engine according to claim 2, wherein each engine block comprises a crankshaft.

18. The intermediate plate according to claim 14, wherein the intermediate plate comprises two sealing faces adapted for respectively sealing one side of the engine blocks.

19. An internal combustion engine, comprising at least two engine blocks which are coupled to one another and each of which includes at least one cylinder, each cylinder being connected to a common drive shaft via a transmission and a clutch.

Description

[0073] The invention will be explained in more detail below with reference to the drawings. In the drawings:

[0074] FIG. 1 shows a perspective view of an internal combustion engine according to the invention,

[0075] FIG. 2 shows the internal combustion engine according to FIG. 1 in a lateral exploded view,

[0076] FIG. 3 shows two cylinder blocks arranged in V-shape with the intermediate plate of the internal combustion engine according to the invention in an exploded perspective view,

[0077] FIG. 4 shows the intermediate plate with first and second crankshafts and the camshaft drive and oil pump drive in a perspective view,

[0078] FIG. 5 shows the intermediate plate with first and second crankshafts and camshaft and oil pump drive in a lateral sectional view,

[0079] FIG. 6 shows a transmission and a clutch of the internal combustion engine in a detailed perspective view,

[0080] FIG. 7 shows another perspective view of the internal combustion engine according to the invention,

[0081] FIG. 8 shows a perspective view of a turbocharger with intercooler,

[0082] FIG. 9 shows another perspective view of the turbocharger with intercooler,

[0083] FIG. 10 shows a perspective view of the internal combustion engine according to the invention with two transmission housings provided on the intermediate plate,

[0084] FIG. 11 shows the transmissions of the embodiment shown in FIG. 10 with a camshaft control in a perspective view,

[0085] FIG. 12 shows means for decoupling rocker arms in a perspective view,

[0086] FIG. 13 shows an alternative embodiment of the means for decoupling rocker arms in a perspective view, and

[0087] FIG. 14 shows an alternative embodiment of the means for decoupling rocker arms in a perspective view.

[0088] One example embodiment of an internal combustion engine 1 according to the invention comprises two V-engines or engine blocks 2, 3 coupled to one another and each having two cylinders 4 (FIGS. 1-3). The engine blocks arranged in V-shape comprise respective cylinders or cylinder heads arranged in V-shape.

[0089] Each cylinder 4 has one piston (FIG. 4) arranged therein, each acting, with one connecting rod, upon a crankshaft 5, 6. The first and the second crankshafts 5, 6 of the first and the second engine block 2, 3 are thus designed separately, that means they are not connected to one another.

[0090] The crankshafts 5, 6 each have their ends borne on an intermediate plate 11 and a first and a second crankcase 8, 10, respectively. The intermediate plate 11 is arranged between the two crankcases 8, 10. The crankcases 8, 10 are arranged on the outer sides of the engine blocks 2, 3 facing away from the intermediate plate 11.

[0091] The intermediate plate 11 is adapted for sealing and connecting the first and the second engine blocks 2, 3 to a first and a second crankcase 8, 10 (FIGS. 2-5).

[0092] The intermediate plate 11 is a disk-shaped element having boreholes 12 arranged on its radial circumference, which are equally spaced apart from one another, for connecting it to the two crankcases 8, 10. In the middle of the intermediate plate 11, a bearing borehole 13 is arranged transversally with respect to the intermediate plate 11 (FIG. 5).

[0093] The bearing borehole 13 has one end 18, on the bearing side, of the first crankshaft 5 and one end 19, on the bearing side, of the second crankshaft 6 arranged therein.

[0094] The bearing-side end 18 of the crankshaft 5 is a tubular section 20. The bearing-side end 19 of the second crankshaft 6 is a pin-shaped section 21. The outer diameter of the pin-shaped section 21 is smaller than the inner diameter of the tubular section 20. (Is that true?)

[0095] The bearing borehole 13 is a bearing means 17 such as a sliding bearing, a ball bearing, or a roller bearing provided between the inner surface of the bearing borehole and the outer surface of the tubular section 20.

[0096] The tubular section of the bearing-side end 18 of the first crankshaft 5 has another bearing means 17 arranged therein. In this bearing means and thus in the tubular section, the pin-shaped section 21 of the second crankshaft 6 is rotational-mounted.

[0097] Due to the bearing means 17 in the bearing borehole 13 and the further bearing means 17, the two crankshafts are, in their rotational movement, completely decoupled from one another.

[0098] The bearing borehole 13 is on both sides of the intermediate plate elongated by respective pipe parts 14 and has an extended diameter. The pipe parts 14 are connected to the intermediate plate 11 by means of additional reinforcing struts 15. The hollow spaces of the pipe parts form bearing openings 16.

[0099] These bearing openings 16 also have bearing means 17 arranged therein, in which crank cheeks 36 of the first and the second crankshafts 5, 6 are borne (FIG. 5).

[0100] The two crankshafts 5, 6 are thus, in the intermediate plate 11, borne both in the region of the crank cheek 36 and in the center of the bearing opening 13 of the intermediate plate 11. This makes it possible to make the axial distance of the bearings of each crankshaft large. This makes it possible to make the bearing distances of each crankshaft significantly larger than in the case in which, in the center of the intermediate plate, a separate bearing would be provided for each crankshaft portion.

[0101] Alternatively, it may also be provided that the bearing-side end 18 of the first crankshaft 5 and the bearing-side end 19 of the second crankshaft 6 are borne in a manner decoupled from one another, each in its own bearing means 17 in the bearing opening 16 (not shown).

[0102] The intermediate plate 11 has also a camshaft drive 22 and an oil pump drive 23 provided thereon (FIGS. 3-5).

[0103] The camshaft drive 22 and the oil pump drive 23 are designed as bevel gear transmissions and extend from the region of the bearing borehole 13, in which they engage one of the crankshafts 5, 6, radially to the outside up to the camshafts 33 or an oil pump. These drives may also be designed as spur gear transmissions or different types of transmissions.

[0104] Furthermore, a means 39 for, preferably mechanically, decoupling rocker arms 40 and the camshaft 33 is provided (FIGS. 12-14).

[0105] The means 39 comprises an eccentric shaft 41 on which the rocker arms 40 are borne in an eccentric manner such that the rotational point of the rocker arms 40 can be displaced such that the rocker arms 40 can, due to the displacement of the rotational points in the operated condition, no longer reach the valves 44.

[0106] Consequently, the valves remain closed even during a lifting movement of the pushing rod 41, thereby making it possible to switch off cylinders.

[0107] The eccentric shaft can be turned for example by means of a hydraulic cylinder 42. This hydraulic cylinder or the hydraulic cylinders can be controlled via a valve such as a magnetic valve, an electric valve or a mechanical valve. To operate the cylinder 42, the engine oil pressure from the engine circuit can be used.

[0108] The eccentric shaft 43 can thus be arranged in a rocker arm is not engaged position and in a rocker arm is engaged position.

[0109] Furthermore, a spring 45 may be provided, which presses the rocker arm onto the pushing rod 41 also when the eccentric shaft is rotated, thereby holding it on the camshaft 33.

[0110] The spring 45 ensures that the rocker arms 40 cannot freely swing when the eccentric shaft is turned, and thus that the pushing rod 41 is being held on the camshaft.

[0111] Alternatively, the eccentric shaft 43 may also be operated electromagnetically or mechanically.

[0112] According to an alternative embodiment, a spring 46 may be provided, which presses the pushing rod 41 upwards within the cylinder heads. This way, the rocker arm 40 also remains on the valve. This causes a distance between the camshaft 33 and the pushing rod 41 generated by turning the eccentric shaft 43, such that neither the pushing rod 41 nor the rocker arm 40 nor the valve 44 are operated. This also results in switching off cylinders by having the valves 44 remain closed.

[0113] Alternatively, the rocker arms 40 may also be mechanically decoupled from the camshafts 33 via a means that displaces the tappets, which this way can be disengaged from the rocker arms such that the tappets no longer have a connection to the rocker arms.

[0114] Alternatively, it may be provided that the pushing rods in the region of the camshaft are displaced such that the transmission of the lifting movement from the camshaft to the pushing rod is disengaged.

[0115] The first and second engine blocks 2, 3, arranged in a V-shape form, form in the region between their cylinders, a V-clearance 24. In the region of the V-clearance between the cylinder heads 25 of the cylinders 4, a drive shaft 26 is arranged.

[0116] The crankcases 8, 10 arranged on the outside each have a transmission 72 and a clutch 28 connecting the respective ends 7, 9, on the output sides of the first crankshaft 5 and the second crankshaft 6 to the drive shaft 26 arranged therein (FIG. 6). Such an arrangement of the transmissions 27 is referred to as external transmission arrangement.

[0117] The external gear engagements make it possible to achieve a small distance between the cylinder pairs of the two engine parts, thereby being able to achieve a high running smoothness.

[0118] The transmissions 27 are designed as belt transmissions. Alternatively, the transmissions 27 may also be designed as gear transmissions.

[0119] The two transmissions 27 may, according to a preferred embodiment, be arranged in the region in which the two engine blocks 2, 3 are connected to or coupled to one another. This means, the transmissions 27 are arranged in the region of the intermediate plate 11. Such arrangement of the transmissions 27 is referred to as internal transmission arrangement.

[0120] The transmissions 27 are then preferably designed as gear transmissions.

[0121] In particular, the transmissions 27 may be designed such that in each case a first gear 47 arranged on the crankshaft can be connected, via a second gear 48, to a third gear arranged on the output shaft 26. This makes it possible to design or construct the transmission smaller at a given transmission ratio.

[0122] Furthermore, it is provided that a fourth gear 50 arranged on a camshaft is, via a fourth gear coupled to the second gear 48, engaged in a way that the camshaft is driven or controlled via the gear pair consisting of the fourth and the fifth gear 50, 51.

[0123] The gears are covered by a housing 52 fixed to the intermediate plate 11.

[0124] The clutches 28 are designed as claw clutches. The claw clutches are designed such that one claw of one half of the claw clutch has a different geometry than the remaining claws such that this one claw can only be coupled into one correspondingly complementarily designed recess of the other half of the claw clutch. This ensures that the two halves of the clutches 28 can only engage one another in a certain rotational position.

[0125] Each of the two engine blocks 2, 3 is provided with a turbocharger 29. The internal combustion engine 1 is, due to the two separate turbocharger systems 29, designed redundantly with respect to the air supply. That means, if one engine part fails and the turbocharger is damaged, this only leads to a 50% loss of power, because the remaining engine part with turbocharger still reaches its full power.

[0126] Alternatively, one single turbocharger is also conceivable.

[0127] In a pipe part provided between the turbochargers 29 and the intake bends to the cylinders, intercoolers (FIGS. 7-9) for cooling the compressed and heated intake air are integrated. These coolers are formed of lamella-like pipe parts to increase their surface area. In the interior part of these pipe parts, the compressed and heated air flows from the turbochargers to the intake pipes and dissipates the heat to the corrugated pipe lamellae. On the outside of the pipe lamellae, cooling air flows in the opposite direction around the lamellae, thereby dissipating the heat. The opposing airflows render an optimum cooling effect combined with a very small installation space and low weight.

[0128] The output shaft 26 has two centrifugal fans 31 provided thereon. Due to the centrifugal fans, the engine does not have to be supplied with an external cooling airflow. Due to the centrifugal fans, the cylinders are always cooled as long as the drive shaft is rotating, which means that the engine is running.

[0129] In the region of the second engine block 3, a water cooling means 35 having two separate cooling circuits for cooling the two engine blocks 2, 3 is provided.

[0130] In addition, a cooling fan 30 is provided in this region to increase the cooling capacity. This cooling fan 30 provides an airflow both for the two intercoolers and for the water cooling means 35. A fan housing of the cooling fan is designed such as to guide, in the upper region, part of the cooling air flow to the intercoolers. The lower region ensures that the cooling air flow is supplied to the water cooling means 35.

[0131] On one end 32, on the output side, of the drive shaft, two separate generators 34 are provided to ensure sufficient power supply at any time, which means also if one generator fails. These generators may also be electric drives, thus forming a hybrid drive.

[0132] The camshaft drive explained above is arranged at the center of the intermediate plate. Alternatively, the camshaft drive and the oil pump drive may be arranged on the opposite/external housing sides.

[0133] For further enhancing the failure safety and/or to provide an additional increase in power, the internal combustion engine may additionally comprise an electric drive (FIGS. 2-7) such that the internal combustion engine is designed as a hybrid drive. With the electric drive, sufficient power and sufficient torque on the drive shaft can be provided for emergency operation (for example for reaching the next airport) in order to drive a vehicle, in particular an aircraft, equipped with the internal combustion engine, even if both engine blocks of the internal combustion engine fail.

[0134] The process of coupling-in and coupling-out the two engine blocks is described in the following in further detail.

[0135] In order to shut down one of the two engine blocks in case of loss of torque or complete failure, sensors are provided, by means of which an operating condition of the two engine blocks can be detected independently from one another.

[0136] These sensors may preferably be adapted for independently detecting the torque of the two engine blocks or the exhaust gas temperatures of the two engine blocks or for detecting other suitable characteristics for determining the operating condition. These sensors are therefore in the following subsumed with the term operating condition sensors.

[0137] The operating condition sensors may be arranged as torque sensors in both clutches. The torque sensors may be implemented as electronic sensors for torque detection, for example as piezoelectric sensors or contact-free torque sensors. The Fraunhofer ITWM sells an inductive sensor for contact-free detection of torque. The measuring concept of this sensor is based on the anisotropic magnetostrictive effect in ferromagnetic shaft surfaces. This effect causes, depending on the mechanical torsional stresses on the place of measurement, a different magnetic permeability in direction of the tensile stresses and compressive stresses. The sensor serves to measure this change in permeability, which is, in a large measurement range, proportional to the torsional stress on the shaft surface.

[0138] Another possibility for torque detection is to provide, on the transmission, a spring-loaded pulley, such as a tensioner pulley, abutting on one run of the belt. Depending on whether the belt transmission drives the drive shaft or the engine block, either the one or the other run of the belt is under tension. This tension can be detected with the tensioner pulley and a corresponding sensor.

[0139] In addition and/or alternatively, at least two exhaust sensors may be provided, which are integrated into the exhaust system of the two engine blocks such that the exhaust gas temperatures of the two engine blocks can be monitored independently from one another.

[0140] The internal combustion engine according to the invention comprises a controller (not shown), which monitors the torque and/or the exhaust gas temperature of the two engine blocks by means of the sensors. As soon as the torque of one of the two engine blocks has, over a longer period of time, for example more than 0.5 or 1 or 1.5 or 2 or 3 or 4 seconds, a predetermined difference from the other engine block, the controller controls the clutch of the respective engine block and decouples it. This way, the crankshaft of this engine no longer has to rotate along and the other engine can continue to operate without the friction resistance of the failing engine block.

[0141] Aside from these automatic decoupling processes by means of a controller, manual decoupling may also be provided additionally or alternatively.

[0142] If one motor part no longer operates correctly, the driver, in particular the pilot, is notified by the control electronics. They can then decouple the respective engine by manually or electrically operating the respective clutch.

[0143] If the clutches are designed as claw clutches, the engine can only be coupled-in again during standstill or after landing, because this requires that the correct rotation angle position of the two engines with respect to one another must be ensured.

[0144] In the preferred composition, the internal combustion engine according to the invention comprises twoapart from the mirrored camshaftcompletely identical engines or engine blocks, which can each be operated alone.

[0145] One possibility to reduce components would, for example, be to separate the cooling water containers and oil containers as well as the coolers on the side of the circuit, while, however, combining the double containers or coolers in one respective double component.

[0146] It is also possible to employ other clutches, which accomplish the function of an unambiguous angular position, as a clutch.

[0147] Alternatively, it may be possible to couple-in during operation, provided it is possible to provide a clutch that ensures, during operation, the unambiguous angular position during the process of coupling-in. In case of an emergency, it would also be conceivable to couple-in if the two engine parts have a random angular position with respect to one another; however, in this case, the imbalances of the two engine parts may, in an unfavorable case, add up and thus double.

[0148] The two transmissions may also be arranged in the region of the intermediate plate.

[0149] The at least two engine blocks are preferably arranged in a V-shape. However, they may also be arranged in a boxer arrangement or in-line arrangement.

[0150] With the principle according to the invention, it is also possible to connect more than two, for example three or four, engine blocks.

[0151] According to another embodiment, not only two two-cylinder engine blocks, or two engine blocks with two cylinders, but also for example four four-cylinder engine blocks, one four-cylinder engine block and one two-cylinder engine block, or two three-cylinder engine blocks, are coupled in a manner according to the invention in order to be able to realize small but even more powerful units. Principally, it is also possible to couple three two-cylinder engine blocks, wherein a distance needs to be kept between two engine blocks in order to provide a transmission and a clutch for the output to the drive site.

[0152] Alternatively, it is also conceivable to couple two or more engine blocks to one another in a manner according to the invention.

[0153] Principally, an engine block may also comprise only one cylinder.

[0154] The engine blocks may also be adapted as in-line engines or boxer engines.

[0155] The internal combustion engine according to the invention comprises all components required for operating one engine block of the engine twice; merely the drive shaft is provided only once. That means, there are two completely separate power supply systems which are supplied by two separate generators and connected to the on-board power system via diodes for safeguarding. The engine according to the invention comprises two separate cooling circuits and oil circuits and correspondingly two cooling pumps and two oil pumps. That means, even if one engine block fails, the operation of the second engine block is still ensured.

LIST OF REFERENCES

[0156] 1 internal combustion engine [0157] 30 fan [0158] 2 first engine block [0159] 31 centrifugal fan [0160] 3 second engine block [0161] 27 transmission [0162] 4 cylinder [0163] 28 coupling [0164] 5 first crankshaft [0165] 32 end of the drive shaft on the output side [0166] 6 second crankshaft [0167] 7 end on the output side [0168] 33 camshaft [0169] 8 first crankcase [0170] 34 generator [0171] 9 end on the output side [0172] 35 water cooling means [0173] 10 second crankcase [0174] 36 crank cheek [0175] 11 intermediate plate [0176] 37 electric drive [0177] 12 boreholes [0178] 38 intercooler [0179] 13 recesses [0180] 39 means for decoupling rocker arms [0181] 14 pipe part [0182] 15 reinforcing struts [0183] 40 rocker arm [0184] 16 bearing borehole [0185] 41 pushing rod [0186] 17 bearing means [0187] 42 hydraulic cylinder [0188] 18 end on the bearing side [0189] 43 eccentric shaft [0190] 19 end on the bearing side [0191] 44 valve [0192] 20 tube-shaped section [0193] 45 spring [0194] 21 pin-shaped section [0195] 46 spring [0196] 22 camshaft drive [0197] 47 first gear [0198] 23 oil pump drive [0199] 48 second gear [0200] 24 V-clearance [0201] 49 third gear [0202] 25 cylinder head [0203] 50 fourth gear [0204] 26 drive shaft [0205] 51 fifth gear [0206] 29 turbocharger [0207] 52 housing