internal combustion engine

Abstract

Internal combustion engine, with cylinders (39, 40) forming cylinder banks (41, 42), with a crankshaft (44) on which cylinder pistons (43) act via a connecting rod (10), each connecting rod having an eccentric adjusting device (13) comprising an eccentric interacting with an eccentric lever (14) and eccentric rods (15, 16), each of the eccentric rods acting on the eccentric lever and on a piston (20, 21) guided in a hydraulic chamber (22, 23), a switching position of a changeover valve (29) determining which of the hydraulic chambers is filled and which of the hydraulic chambers is emptied via return lines (30, 31, 47), at least one of the return lines (47) opening into a hydraulic oil collection chamber through a through-hole in a connecting rod bearing shell (35), in the area of ​​all cylinder banks the return lines (47) opening in the area of ​​the openings are inserted into the connecting rods of all cylinders in such a way,that all outlets (48) of these return lines, viewed in the direction of rotation of the connecting rod journal, are located either in front of or behind a longitudinal axis (L) of the respective connecting rod.

Description

[0001] The invention relates to an internal combustion engine with an adjustable compression ratio.

[0002] Fig. Figure 1 shows a connecting rod 10 of an internal combustion engine with an adjustable compression ratio, as known from DE 10 2010 016 037 A1. The connecting rod 10 has a bearing eye 11 and a bearing eye 12, the bearing eye 11 being the connection of the connecting rod 10 to a Fig. 1 crankshaft not shown, namely to a connecting rod journal of the crankshaft, and the connecting rod bearing eye 12 of the connection of the connecting rod 10 to a in Fig. 1. The connecting rod 10 is associated with an eccentric adjusting device 13, which acts as a guide for the cylinder piston of the internal combustion engine (not shown). Fig. The eccentric (not shown) comprises an eccentric lever 14 and eccentric rods 15, 16. The eccentric has a bore with a center point 18 arranged eccentrically to a center point 17 of a connecting rod bearing eye bore, the bore in the eccentric accommodating a cylinder piston pin. The eccentric adjusting device 13 serves to adjust an effective connecting rod length l. eff, where the connecting rod length is defined as the distance from the center point 18 of the bore in the eccentric to a center point 19 of the bearing eye 11. The eccentric body 14 is rotated, thus changing the effective connecting rod length l. effThe eccentric rods 15, 16 are displaceable. Each eccentric rod 15, 16 is associated with a piston 20, 21, which is slidably guided in a hydraulic chamber 22, 23 of the connecting rod 10. A hydraulic pressure exists in the hydraulic chambers 22, 23, which acts on the pistons 20, 21 associated with the eccentric rods 15, 16, whereby the displacement of the eccentric rods 15, 16 is possible or impossible depending on the amount of oil in the hydraulic chambers.

[0003] The adjustment of the eccentric adjusting device 13 is initiated by the action of mass and load forces from the internal combustion engine, which act on the eccentric adjusting device 13 during a power stroke of the internal combustion engine. During a power stroke, the directions of action of the forces acting on the eccentric adjusting device 13 constantly change. The adjustment movement is assisted by the hydraulically oil-lubricated pistons 20, 21, which act on the eccentric rods 15, 16. The pistons 20, 21 prevent the eccentric adjusting device 13 from resetting due to the varying directions of action of the forces acting on it. The eccentric rods 15, 16, which interact with the pistons 20, 21, are connected to the eccentric body 14 on both sides. The hydraulic chambers 22 and 23, in which the pistons 20, 21 are guided, can be supplied with hydraulic oil via supply lines 24 and 25 from the lifting bearing eye 11.Check valves 26 and 27 prevent the hydraulic oil from flowing back from the hydraulic chambers 23 and 24 into the supply lines 24 and 25. A changeover valve 29 is located in a bore 28 of the connecting rod 10. The switching position of the changeover valve 29 determines which of the hydraulic chambers 22 and 23 are filled with hydraulic oil and which of the hydraulic chambers 22 and 23 are emptied, thereby determining the direction of adjustment or rotation of the eccentric adjusting device 13. The hydraulic chambers 22 and 23 are in contact with the bore 28, which houses the changeover valve 29, via return lines 30 and 31, respectively. [The text abruptly ends here, so the translation stops as well.] Fig. 1 an actuating means 32, a spring device 33 and a control piston 34 are shown schematically, the function of these components of the switching valve 29 is already known from DE 10 2010 016 037 A1.

[0004] From DE 10 2013 111 617 A1, a further switching valve of a connecting rod of an internal combustion engine with an adjustable compression ratio is known.

[0005] As explained above, the hydraulic oil, which acts on the pistons 20, 21 guided in the hydraulic chambers 22, 23, is supplied to the hydraulic chambers 22, 23 from the lifting bearing eye 11 via the supply lines 24 and 25. The connecting rod 10 thus engages with the lifting bearing eye 11 at the Fig. Figure 1 (not shown) indicates that a connecting rod bearing shell 35 is arranged between the crankshaft, namely its connecting rod journal, and the crankpin eye. A check valve 26, 27 interacts with each hydraulic chamber 22, 23. These check valves 26, 27 are received in corresponding recesses 36, 37 of the connecting rod 10. The hydraulic chambers 22 and 23 are in contact with the bore 28, which receives the changeover valve 29, via the return lines 30 and 31, respectively. A further return line (in Fig. (1 not shown) the hydraulic oil can be drained from the switching valve 29 or the bore 28 accommodating the switching valve 29 in the direction of a hydraulic oil collection chamber of the connecting rod 10 or an adjacent opening in the connecting rod bearing shell 35 of the connecting rod 10.

[0006] Fig. Figure 2 shows a section of an internal combustion engine 38 known from the prior art in the area of ​​two cylinders 39 and 40, respectively, which are positioned in different cylinder banks 41 and 42. A piston 43 is shown for each cylinder 39, 40, with each piston 43 being connected via a connecting rod 10 to a Fig. The crankshaft 44 shown in Figure 2 is coupled to the connecting rod journals 45 and 46 of the crankshaft 44, to which the connecting rods engage via their bearing eye 11. The connecting rod journals 45 and 46 are also referred to as crankshaft bearing journals for the connecting rods 10.

[0007] Although the in Fig. Although the connecting rods 10 shown in the two diagrams differ from each other particularly with regard to the design of the switching valves 29, the design of the supply lines 24, 25, and the design of the return lines 30, 31, the operating principle of the connecting rods 10 corresponds to the Fig. 2 the operating principle of the connecting rod 10 the Fig. 1, so that the same reference numbers are used for identical assemblies. Fig. Figure 2 shows in particular the course of the supply lines 24, 25, via which the hydraulic chambers 23, 23 can be supplied with hydraulic oil, as well as the course of the return lines 30, 31, via which oil can be conveyed from the hydraulic chambers 23, 23 towards the switching valves 29, namely the bores 28 accommodating the switching valves 29, as well as further return lines 47, via which the return oil can be conveyed from the respective switching valve 29 towards the opening of the connecting rod bearing shell 35 of the connecting rod 10.

[0008] Fig. 2 the relative position of an outlet 48 of the return lines 47 extending from the respective switching valve 29 towards the respective hydraulic oil collection chamber can be determined, wherein Fig. 2 can be seen that, with respect to the longitudinal axes L of the connecting rods 10 extending through the lifting bearing eye 11 and the connecting rod bearing eye 12, the outlets 48 of the return lines 47 are arranged at different positions, namely for the in Fig. 2. The right connecting rod 10 shown in the direction of rotation of the crankshaft or the respective connecting rod journal, viewed along the respective longitudinal axis L, and for the Fig. 2. Left connecting rod 10 shown in the direction of rotation of the crankshaft 10 or the respective bearing journal, viewed in front of the respective longitudinal axis L. The direction of rotation of the crankshaft 44 is in Fig. 2 is visualized by arrow I, the directions of rotation of the connecting rod journals 45, 46 are shown by arrows II.

[0009] In the case of internal combustion engines known from the prior art with adjustable compression ratio according to Fig. 2. It has been found that the connecting rod bearings of the connecting rods 10 at the connecting rod journals 45, 46 do not have sufficient stability. Therefore, there is a need for an internal combustion engine with an adjustable compression ratio whose connecting rod bearings exhibit increased stability.

[0010] The purpose of the invention is to create an internal combustion engine.

[0011] This problem is solved by an internal combustion engine according to claim 1.

[0012] According to the invention, in the area of ​​all cylinder banks of the internal combustion engine, the return lines of the connecting rods of all cylinders, which open into the area of ​​the respective opening of the connecting rod bearing shells of the connecting rods, are introduced into the respective connecting rod in such a way that the opening points of these return lines of all cylinders, viewed in the direction of rotation of the connecting rod journal, are either all located in front of or the opening points of these return lines of all cylinders, viewed in the direction of rotation of the connecting rod journal, are all located after a longitudinal axis of the respective connecting rod extending through the crank bearing eye and the connecting rod bearing eye.

[0013] In the combustion engine according to the invention, the advantage can be achieved that the oil flowing back via the return lines towards the opening of the connecting rod is introduced in such a way during micro-movements of the hydraulic pistons or during switching of the eccentric adjusting device that the hydrodynamic pressure build-up occurs in the same direction in the area of ​​all cylinders of all cylinder banks. This increases the stability of the connecting rod bearing.

[0014] Preferably, in the area of ​​all cylinders of the internal combustion engine, the return lines of the connecting rods, which open into the area of ​​the respective connecting rod bores, are integrated into the respective connecting rods in such a way that all openings of these return lines, viewed in the direction of rotation of the connecting rod journal, lie along a longitudinal axis of the respective connecting rod extending through the crankpin bore and the connecting rod bearing bore. This promotes or supports the hydrodynamic pressure build-up in the area of ​​each connecting rod. In the area of ​​all connecting rods, return oil entering a collecting chamber 10, which is formed in the area of ​​the connecting rod bearing bore opening, is conveyed via the return lines towards the respective connecting rod cap of the respective connecting rod, thus promoting the formation of the lubricating film in the area of ​​the respective connecting rod bearing.

[0015] Preferred embodiments of the invention are described in the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being limited thereto. The drawing shows: Fig. 1 a connecting rod of an internal combustion engine known from the prior art; Fig. 2 a detail of an internal combustion engine known from the prior art in the area of ​​two cylinders; and Fig. 3 a detail of an internal combustion engine according to the invention in the area of ​​two cylinders.

[0016] An internal combustion engine according to the invention 49 (see Fig. 3) with an adjustable compression ratio has several cylinders 39, 40 which form several cylinder banks 41, 42 of the internal combustion engine 49.

[0017] Each cylinder 39, 40 of the internal combustion engine 49 with an adjustable compression ratio has a piston 43 which is coupled to the crankshaft 44 of the internal combustion engine 49 via a connecting rod 10.

[0018] Each connecting rod 10 has a connecting rod bearing eye 12 at one end and a lifting bearing eye 11 at the opposite end.

[0019] Each connecting rod 10 engages with its bearing eye 11 a connecting rod journal 45, 46 of the crankshaft 44 and with its bearing eye 12 a cylinder piston 43 of the internal combustion engine 49. A connecting rod bearing shell 35 is arranged between the respective connecting rod journal 45, 46 of the crankshaft 44 and the bearing eye 11 of the respective connecting rod 10.

[0020] The internal combustion engine 49 with adjustable compression ratio has an eccentric adjusting device 13 in the area of ​​each connecting rod 10 for adjusting the effective connecting rod length of the respective connecting rod 10.

[0021] The eccentric adjustment device 13 of the respective connecting rod 10 has an eccentric (in Fig. 3 not shown), an eccentric lever 14 (in Fig. 3 not shown) and eccentric rods 15, 16, which can be moved depending on a hydraulic pressure prevailing in the hydraulic chambers 22, 23 cooperating with the eccentric rods to adjust the compression ratio.

[0022] The hydraulic chambers 22, 23, which interact with the eccentric rods 15, 16, can be supplied with hydraulic oil from the lifting bearing eye 11 of the respective connecting rod 10, namely via supply lines 24, 25.

[0023] A changeover valve 29 is accommodated in a bore 28 of the connecting rod 10. The switching position of the changeover valve 29 determines which of the hydraulic chambers 22, 23 is filled with hydraulic oil and which of the hydraulic chambers 22, 23 is emptied.

[0024] The hydraulic chambers 22, 23 can be emptied via return lines 30, 31, 47 depending on the switching position of the changeover valve 29 in the direction of the lifting bearing eye 11.

[0025] The return lines 30, 31 of each connecting rod 10 extend from the hydraulic chambers 22, 23 of the respective connecting rod 10 towards the switching valve 29 of the respective connecting rod 10.

[0026] The return line 47 of each connecting rod 10 extends from the changeover valve 29 of the respective connecting rod 10 towards the connecting rod bearing eye 11 of the respective connecting rod 10, preferably towards a hydraulic oil collection chamber of the respective connecting rod 10 formed on the connecting rod bearing eye 11 of the respective connecting rod 10, extending adjacent to the connecting rod bearing shell 35, and preferably designed as a groove. The hydraulic oil collection chamber can also be designed as a bore. Reference is made below to a hydraulic oil collection chamber designed as a groove. The hydraulic oil collection chamber, preferably designed as a groove, communicates with an opening in the connecting rod bearing shell 35.

[0027] Each hydraulic chamber 22, 23 of each connecting rod 10 is acted upon by a check valve 26, 27. The check valves 26, 27 are accommodated in corresponding recesses 36, 37 of the respective connecting rod 10, whereby the check valves 26, 27 allow the hydraulic chambers 22, 23 of the respective connecting rod 10 to be filled from the connecting rod bearing eye 11 via the supply lines 24, 25, but prevent hydraulic oil from flowing back through the supply lines 24, 25 from the hydraulic chambers 22, 23 towards the connecting rod bearing eye 11 of the respective connecting rod 10.

[0028] In the combustion engine according to the invention, the Fig. 3 In the area of ​​each cylinder bank 41, 42, the return line 47, which opens into the groove and thus into the area of ​​the opening of the connecting rod bearing shell 35, is inserted into the respective connecting rod 10 of the respective cylinder 39, 40 in such a way that in the area of ​​all cylinders 39, 40 of all cylinder banks 41, 42, the outlets 48 of the return lines 47, which extend from the respective reversing valve 29 towards the respective crankshaft bearing eye 11, are located in the area of ​​the respective crankshaft bearing eye 11, viewed in the direction of rotation of the crankshaft or in the direction of rotation of the connecting rod journals 45, 46, either all before or all after the longitudinal axis L of the respective connecting rod 10 extending through the crankshaft bearing eye 11 and the connecting rod bearing eye 12.

[0029] Then, if a respective outlet 48 of a return line 47 opening into the groove or in the area of ​​the opening in the connecting rod bearing shell 35 lies in front of the longitudinal axis L extending through the crankshaft bearing eye 11 and the connecting rod bearing eye 12, as seen in the direction of rotation of the crankshaft or in the direction of rotation of the connecting rod journals 45, 46, this means that a delivery direction of return oil entering the respective groove via the respective outlet 48, initiated by the rotation of the crankshaft 44 or the bearing journals 45, 46, is directed away from a crankshaft bearing cap 50 of the respective connecting rod 10. Then, if a respective outlet 48 of a return line 47 opening into the groove or in the area of ​​the opening in the connecting rod bearing shell 35 lies in front of the longitudinal axis L extending through the crankshaft or the connecting rod bearing eye 12, this means that a delivery direction of return oil entering the respective groove via the respective outlet 48, initiated by the rotation of the crankshaft 44 or the bearing journals 45, 46, is directed away from a crankshaft bearing cap 50 of the respective connecting rod 10.Viewed in the direction of rotation of the connecting rod journals 45, 46, the longitudinal axis L extending through the crank bearing eye 11 and the connecting rod bearing eye 12 is said to mean that a delivery direction of return oil entering the respective groove via the respective outlet 48 is directed towards the crank bearing cover 50 of the respective connecting rod 10, initiated by the rotation of the crankshaft 44 or the bearing journals 45, 46.

[0030] In the preferred embodiment shown, these outlet points 48 are all located in the direction of rotation II of the connecting rod journals 45, 46 along the longitudinal axis L of the respective connecting rod extending through the crankshaft bearing eye 11 and the connecting rod bearing eye 12, so that return oil, which enters the respective groove in the area of ​​the crankshaft bearing eye 11 via the respective outlet point 48, is directed towards the crankshaft bearing cover 50 of the respective connecting rod 10 by a pumping direction of the return oil initiated by the rotation of the crankshaft 44 or the rotation of the connecting rod journals 45, 46, in order to support the lubricating film formation in the area of ​​the connecting rod bearing of the respective connecting rod 10 on the respective connecting rod journal 45, 46.The respective connecting rod cap 50 of the respective connecting rod 10 is connected to a lifting bearing upper part 52 of the respective connecting rod 10 via screws 51, wherein the groove into which the respective return line 47 with its opening 48 opens in the area of ​​the opening in the bearing shell is formed in the area of ​​the respective lifting bearing upper part 52.

[0031] A comparison of Fig. 2 and Fig. 3 can be seen to indicate that for the in Fig. 3 Connecting rod 10 shown on the right with regard to the design of the return lines 30, 31 and 47 of the right side of the Fig. 2 connecting rod 10 corresponds to the one shown. Fig. However, the connecting rod 10 shown on the left differs in the design of the return lines 30, 31 and 47 from the return lines 30, 31 and 47 of the one shown in Figure 3. Fig. 2 connecting rod 10 shown on the left, namely, as already explained, in such a way that also in the area of ​​the in Fig. 3 on the left side, the outlet 48 of the respective return line 47 of the connecting rod 10 shown is located in the direction of rotation of the crankshaft or in the direction of rotation of the respective connecting rod journal, according to the respective longitudinal axis L of the connecting rod 10.

[0032] In the exemplary embodiment of the Fig. 3 extends for the connecting rod 10 shown on the left side the return line 47, which extends from the switching valve 29 towards the lifting bearing eye 11, initially towards the supply line 24, in order to open via the supply line 24 into the groove in the area of ​​the lifting bearing eye 11 in the area of ​​the opening of the bearing shell 35.

Claims

[1] Internal combustion engine with adjustable compression ratio, with several cylinders (39, 40), wherein the cylinders (39, 40) form several cylinder banks (41, 42), with a crankshaft (44) to which the cylinder pistons (43) of the cylinders each engage via a connecting rod (10), each connecting rod comprising at least the following assemblies: a connecting rod bearing eye (11) for connecting the respective connecting rod (10) to a connecting rod journal (45, 46) of the crankshaft (44), a connecting rod bearing eye (12) for connecting the respective connecting rod (10) to the cylinder piston (43) of the respective cylinder, an eccentric adjustment device (13) for adjusting an effective connecting rod length of the respective connecting rod (10), wherein the eccentric adjustment device (13) comprises an eccentric cooperating with an eccentric lever (14) and eccentric rods (15, 16), each of the eccentric rods (15, 16) engages the eccentric lever (14) with a first end and a piston (20, 21) with a second end, Each of the pistons (20, 21) is slidably guided in a hydraulic chamber (22, 23), A changeover valve (29) is received in a bore (28) of the respective connecting rod (10), the switching position of which determines which of the hydraulic chambers is filled with hydraulic oil via supply lines (24, 25) starting from the connecting rod bearing eye and which of the hydraulic chambers is emptied via the changeover valve (29) via return lines (30, 31, 47), wherein at least one of the return lines (47) opens into a hydraulic oil collection chamber of the connecting rod (10) in the area of ​​a penetration of a connecting rod bearing shell (35) of the connecting rod (10). characterized by , that In the area of ​​all cylinder banks (41, 42), the return lines (47) of the connecting rods (10) of all cylinders (39, 40) opening in the area of ​​the respective openings are inserted into the respective connecting rod (10) in such a way that the opening points (48) of these return lines (47) of all cylinders, viewed in the direction of rotation of the connecting rod journal (45, 46), are either all in front of or all after a longitudinal axis (L) of the respective connecting rod (10) extending through the crankshaft bearing eye (11) and the connecting rod bearing eye (12). [2] Internal combustion engine according to claim 1, characterized by , that the outlets (48) of the respective return lines (47) of all cylinders (39, 40) of all cylinder banks (41, 42) are located in the direction of rotation of the connecting rod journals (45, 46) according to a longitudinal axis (L) of the respective connecting rod (10) extending through the crank bearing eye (11) and the connecting rod bearing eye (12). [3] Internal combustion engine according to claim 2, characterized by, that a conveying direction of return oil entering the respective collection chamber via the respective outlet (48) in the area of ​​all cylinders (41, 42) is initiated by the rotation of the crankshaft (44) or the bearing journals (45, 46) in the area of ​​all cylinders (41, 42) is directed towards a connecting rod bearing cover (50) of the respective connecting rod (10). [4] Internal combustion engine according to claim 3, characterized by , that the respective outlet (48) opens into the respective collection chamber in the area of ​​a lifting bearing top part (52) of the respective connecting rod (10) closed by the respective lifting bearing cover (50).

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