internal combustion engine

Abstract

Internal combustion engine (1) for a vehicle, comprising a crankcase consisting of two crankcase halves (3) with horizontally arranged cylinder banks, each with a cylinder head (2) arranged on the two crankcase halves (3), with at least one oil pump (4), and with an oil reservoir (5) arranged below the two crankcase halves (3) of the internal combustion engine, wherein a return line (6, 7) and an oil collection line (19) positioned in the respective cylinder head (2) and arranged longitudinally in the cylinder bank are provided for the return of lubricating oil from the respective cylinder head (2) to the oil reservoir (5), characterized in that the respective oil collection line (19) has several suction points (8, 8a),With respect to the longitudinal direction of the cylinder bank, at least one suction point (8) is positioned in a first end section (20) of the respective cylinder head (2) and at least one further suction point (8a) is positioned in a second end section (21) of the respective cylinder head (2) opposite the first end section (20) in the longitudinal direction of the cylinder bank; a return line (6, 7) is provided for each suction point (8) in the first end section (20) of the respective cylinder head (2) and for each further suction point (8a) in the second end section (21) of the respective cylinder head (2), so that the lubricating oil extraction in the respective first end section (20) can be carried out independently of the lubricating oil extraction in the respective second end section (21); the oil pump (4) has a modular design and comprises at least one pressure stage (9) and several suction stages (10), wherein the oil pump (4) has a separate suction stage for each suction point (8, 8a).

Description

The invention relates to an internal combustion engine with a device for the return of lubricating oil according to the preamble of claim 1. In modern internal combustion engines, several manifolds are provided for the return of lubricating oil from different engine areas, at the ends of which a suction port is usually located. From DE 198 28 307 A1, a boxer-type internal combustion engine is known in which two manifolds are provided on the cylinder head for the return of lubricating oil. These manifolds are designed separately and positioned side by side. Both manifolds extend longitudinally along the cylinder head, with only the inner manifold being connected to the interior of the cylinder head. The outer manifold is connected to the inner manifold by a bore. At the end of each manifold, on the same end face of the cylinder head, a suction port is provided, which is connected to an oil pump that pumps the lubricating oil back into an oil pan. A disadvantage of this design, however, is the indirect connection of the outer manifold to the interior of the cylinder head.Furthermore, in certain driving situations, the distance between the suction port and the oil collection point is too great. Therefore, rapid oil return or effective oil extraction from the cylinder head is not possible, especially during dynamic driving conditions such as braking and acceleration. DE 10 2004 019 853 A1 , DE 103 05 781 A1 and JP 2001 115 813 A reveal further state of the art. The invention is therefore based on the objective of providing an improved oil return system for an internal combustion engine, so that optimized oil extraction from the cylinder head into an oil collection container is achieved. This problem is solved by an internal combustion engine according to claim 1. The internal combustion engine according to the invention is characterized in that the respective oil collection line has several suction points, wherein, with reference to the longitudinal direction of the cylinder bank row, at least one suction point is positioned in a first end section of the respective cylinder head and at least one further suction point is positioned in a second end section of the respective cylinder head opposite the first end section in the longitudinal direction of the cylinder bank row. One, two, or more intake ports can be positioned in both the second and first end sections of the cylinder head if this is expedient and necessary for the design of the internal combustion engine. The number of intake ports in the second and first end sections of the cylinder head need not be identical. Additionally, one or more intake ports can be arranged in an intermediate section between the second and first end sections of the cylinder head. By arranging multiple suction points on the oil collection line positioned at the cylinder head, optimized oil extraction and thus rapid oil return are achieved during dynamic driving conditions such as braking, acceleration, and cornering. Since the oil suction points on the cylinder head are directly connected to the return lines in or on the cylinder head, the oil return via the oil pump, which is positioned close to the crankcase, is highly efficient even under dynamic driving conditions. Furthermore, the direct placement of the oil pump within the oil collection reservoir accelerates the oil return process. An oil collection line is provided at each cylinder head, which has a direct connection to the interior of the cylinder head. Since the lubricating oil in the oil collection line in the respective cylinder head typically concentrates in either the first or second end section, depending on the driving conditions, the lubricating oil present there can be extracted without delay by means of the respective suction port or suction point at the corresponding location in the oil collection line according to the invention. Since the cross-sections of the return lines are smaller than those of the oil collection line, the return of the lubricating oil from the respective cylinder head to the oil reservoir is reliably ensured. A return line is provided for each suction point in the first end section of the respective cylinder head and for the suction point in the second end section of the respective cylinder head, so that the lubricating oil extraction in the first end section can be carried out independently of the second end section. This ensures a rapid and optimized return of the lubricating oil from the end section where the lubricating oil accumulates due to a specific driving condition. The oil pump has a modular design and comprises at least one pressure stage and several suction stages. The use of multiple separate return lines enables a modular construction of the oil pump, allowing for optimized pump sizing based on the amount of oil in the respective component. In a further embodiment of the invention, at least one of the return lines is integrated into the cylinder head and / or the crankcase. This shortens the return paths and results in a cost-effective provision of the return lines. In particular, the return paths are further shortened if the return lines are positioned internally in both the cylinder head and the crankcase and / or if the return lines run along an end face of the cylinder head or the crankcase. This utilizes unused installation space within the internal combustion engine for the oil return lines, thus enabling a compact design of the internal combustion engine with reduced weight. In one embodiment of the invention, at least one section of one or more return lines is integrated into the cylinder head or a cylinder head cover. This section connects the suction point, which is located away from the end face of the cylinder head in which the return lines run, to the corresponding return line. Preferably, this section is designed as a connecting channel in or on the cylinder head or in a cylinder head cover. According to an advantageous embodiment of the invention, the suction point in the first end section of the cylinder head is directly connected to the connecting channel, the connecting channel preferably being integrated into the cylinder head or the cylinder head cover. In a further embodiment of the invention, a chain case is positioned or integrated on the cylinder head, in which a suction point is located. Lubricating oil is extracted from the chain case and the cylinder head, or from an adjacent cylinder head section, preferably from the second end section. Thus, the lubricating oil can be extracted simultaneously from the second end section and from the chain case. Furthermore, the proposed separate return of the lubricating oil from the first end section and from the chain case allows for a separate suction stage at the end of each return line, dimensioned according to the oil quantities in the respective component of the internal combustion engine. In a further advantageous embodiment of the invention, at least one oil / air separator is provided in the oil collection tank, through which the lubricating oil drawn from the cylinder head and / or the timing chain case flows before being returned to the oil collection tank. By arranging an oil / air separator in the collection tank, the lubricating oil drawn directly from the cylinder head can be returned to the oil collection tank without air content and in a controlled manner. In one embodiment of the invention, the oil pump is attached to a lower flange surface of the crankcase facing the oil reservoir, preferably positioned within the oil reservoir. It is conceivable that the oil pump is surrounded by lubricating oil. This accelerates the intake of lubricating oil from the cylinder head through the return lines integrated in the cylinder head and the crankcase. Consequently, the arrangement of multiple suction points on the cylinder head ensures rapid oil return, even under dynamic driving conditions such as braking, acceleration, and cornering.Since the oil suction points on the cylinder head are directly connected to the return lines in the cylinder head, the oil return via the oil pump positioned close to the crankcase is very fast and particularly advantageous even under dynamic driving conditions, with the oil return being further accelerated by the direct arrangement of the oil pump in the oil reservoir. Further features and combinations of features will become apparent from the description and the accompanying drawing, which illustrates a preferred embodiment of the invention. The drawings show: Fig. 1 a sectional view of the internal combustion engine according to the invention, Fig. 2 a view of the oil circuit of the internal combustion engine according to Fig. 1, Fig. 3 a view of the oil circuit in the cylinder head of the internal combustion engine according to Fig. 1, Fig. 4 a top view of the oil circuit in the cylinder head of the internal combustion engine according to Fig. 1, Fig. 5 a view of the return lines of the oil circuit in the cylinder head of the internal combustion engine according to Fig. 1, Fig. 6 a top view of the return lines of the oil circuit in the cylinder head of the internal combustion engine according to Fig. 1, Fig. 7 a view of the oil pump of the internal combustion engine according to Fig. 1, and Fig. 8 a further view of the oil pump of the internal combustion engine according to Fig. 1. The internal combustion engine 1 shown in Fig. 1 is a boxer-type engine in which an oil pan 5 is arranged below the two crankcase halves 3. The internal combustion engine 1 is preferably used in a vehicle (not shown) with a direction of travel F. The crankcase of a 6-cylinder boxer engine, shown in section in Fig. 1, consists, without limitation to this embodiment, of two crankcase halves 3 with two horizontally arranged cylinder banks. A cylinder head 2 is arranged on each of the two crankcase halves 3 to the right and left, or laterally, of the two crankcase halves 3. Each cylinder head 2 is provided with a cylinder head cover 23 as shown in Fig. 3. During operation of the internal combustion engine 1, tappets (not shown) oscillate in the cylinder head 2, or camshafts rotate, from whose bearing points lubricating oil escapes and concentrates in an oil collection line 19 as shown in Fig. 4.The oil collection line 19 is arranged along a longitudinal axis of the internal combustion engine 1, i.e., in the direction of travel F of the vehicle. During operation of the internal combustion engine 1, the lubricating oil collects in the oil collection line 19, for which two suction points 8 and 8a, respectively, and two return lines 6 and 7 are provided for extracting the lubricating oil from the oil collection line 19. According to the present invention, the first suction point 8, relative to the direction of travel F of the vehicle, is positioned in a front or first end section 20 of the cylinder head 2, with the second suction point 8a being arranged in a rear or second end section 21 of the cylinder head 2, opposite the first suction point 8. The second suction point 8a is provided in a chain case 24 arranged on the cylinder head 2. Thus, the lubricating oil is drawn from the chain case 24 and from the adjacent cylinder head section in the rear or second end section 21. This allows the lubricating oil to be drawn from the rear or second end section 21 and from the chain case 24 simultaneously. Lubricating oil is extracted from the front or first end section 20 independently of the lubricating oil extraction from the rear or second end section 21 via the separately formed return lines 6 and 7. As shown in Figs. 1, 3, and 4, the return lines 6 and 7 run within the cylinder head 2 and the crankcase 3. They are integrated into both the cylinder head 2 and the crankcase 3 and positioned internally. A section 22 of the return line 7 is integrated into the cylinder head cover 23 and serves as a connecting channel. The suction point 8 in the front or first end section 20 is directly connected to the connecting channel 22. However, according to the present invention, the connecting channel 22 can also be integrated into the cylinder head 2 instead of the cylinder head cover 23. The arrangement of the two suction points 8 and 8a according to the invention enables reliable extraction of the lubricating oil from the cylinder head 2 in both the front or first end section 20 and the rear or second end section 21, regardless of where the lubricating oil concentrates depending on the driving conditions. If the vehicle, and thus the internal combustion engine 1, accelerates in a right-hand curve, the lubricating oil concentrates in the rear or second end section 21 on the left side where the suction point 8a is located. Conversely, if the vehicle, and thus the internal combustion engine 1, brakes in a right-hand curve, the lubricating oil concentrates in the front or first end section 20 where the suction point 8 is located. This ensures a rapid return of the lubricating oil from the respective end section where it is currently accumulating. To further optimize the oil circuit, the present invention provides for the arrangement of the oil pump 4 within the oil reservoir 5. The oil pump 4 shown in Fig. 1 has an upper flange 25 which abuts a lower flange of the crankcase 16 as shown in Fig. 1. The oil pump 4, as shown in Figs. 7 and 8, is modularly formed from several suction stages 10 and a pressure stage 9. As shown in Fig. 1, the arrangement of the oil pump 4 between the crankcase 3 and the oil sump allows for a direct and therefore rapid return of the lubricating oil from the cylinder head 2. The modular design of the oil pump 4 allows for separate lubricating oil extraction from the cylinder head 2. In the present embodiment, four separate suction stages 10 are provided for extracting the lubricating oil from the respective end sections 20 and 21. This enables rapid lubricating oil extraction from each cylinder head, left and right, at two different locations 8 and 8a. This optimizes oil extraction under all driving conditions. Preferably, the oil pump 4 has additional suction stages 28 for an exhaust gas turbocharger (not shown). The lubricating oil drawn from the respective cylinder head 2 is conveyed by the suction stages 10 of the oil pump 4 into two oil / air separators 11, thus defoaming the lubricating oil drawn from the cylinder head 2. In the present embodiment, one oil / air separator 11 is provided within the oil pump 4 for each cylinder head 2.The lubricating oil extracted from the cylinder head 2 by the four suction stages 10 flows into a collection channel within the oil reservoir 5 and is then distributed approximately equally between the two oil / air separators 11. This ensures that the lubricating oil is distributed across both halves of the oil reservoir 5. The two oil / air separators 11 are positioned on the right and left outer sides of the oil reservoir 5, preferably in a horizontal arrangement, and are arranged such that at least one of the two oil / air separators remains above the oil level even during cornering and / or braking and acceleration. The defoamed lubricating oil then flows into the oil reservoir 5. Consequently, reliable separation of oil and air is ensured in the oil / air separator. The pressure stage 9 of the oil pump 4 draws the lubricating oil back in through the suction snorkel 15 and distributes it to the corresponding points 27 within the internal combustion engine 1. The design of the oil circuit of the internal combustion engine 1 according to the invention prevents the accumulation of lubricating oil in the cylinder head 2 and the chain case 24 during both strong acceleration and deceleration. The arrangement of several suction points 8 and 8a on the cylinder head 2, which are connected to the oil pump 4 by separate suction stages 10, ensures that the lubricating oil accumulated in the cylinder head 2 is quickly extracted, even during acceleration or cornering. Furthermore, the oil circuit of the internal combustion engine 1 includes an oil module 12 on which an oil filter assembly 18 is arranged. Blow-by gases drawn in from a crankcase ventilation line 14 are fed to the oil module 12, which comprises a bracket on which the oil filter assembly 18, an oil pre-separator 13 in the form of a chamber, an oil-water heat exchanger 17, and a fine oil separator 26 are mounted.

Claims

Internal combustion engine (1) for a vehicle, comprising a crankcase consisting of two crankcase halves (3) with horizontally arranged cylinder banks, each with a cylinder head (2) arranged on the two crankcase halves (3), with at least one oil pump (4), and with an oil reservoir (5) arranged below the two crankcase halves (3) of the internal combustion engine, wherein a return line (6, 7) and an oil collection line (19) positioned in the respective cylinder head (2) and arranged longitudinally in the cylinder bank are provided for the return of lubricating oil from the respective cylinder head (2) to the oil reservoir (5), characterized in that the respective oil collection line (19) has several suction points (8, 8a),With respect to the longitudinal direction of the cylinder bank, at least one suction point (8) is positioned in a first end section (20) of the respective cylinder head (2) and at least one further suction point (8a) is positioned in a second end section (21) of the respective cylinder head (2) opposite the first end section (20) in the longitudinal direction of the cylinder bank; a return line (6, 7) is provided for each suction point (8) in the first end section (20) of the respective cylinder head (2) and for each further suction point (8a) in the second end section (21) of the respective cylinder head (2), so that the lubricating oil extraction in the respective first end section (20) can be carried out independently of the lubricating oil extraction in the respective second end section (21); the oil pump (4) has a modular design and comprises at least one pressure stage (9) and several suction stages (10), wherein the oil pump (4) has a separate suction stage for each suction point (8, 8a). Internal combustion engine according to claim 1, characterized in that at least one of the return lines (6, 7) is integrated into the respective cylinder head (2) and / or into the crankcase half (3). Internal combustion engine according to one of the preceding claims, characterized in that the return lines (6, 7) are positioned, at least partially, inside both the respective cylinder head (2) and the respective crankcase half (3). Internal combustion engine according to one of the preceding claims, characterized in that the return lines (6, 7) run, at least partially, along an end face of the respective cylinder head (2). Internal combustion engine according to one of the preceding claims, characterized in that at least one section (22) of a return line (6, 7) is integrated as a connecting channel in the respective cylinder head (2) or in a respective cylinder head cover (23). Internal combustion engine according to claim 5, characterized in that the suction point (8) in the first end section (20) of the respective cylinder head (2) is directly connected to the connecting channel (22). Internal combustion engine according to one of the preceding claims, characterized in that a chain case (24) is positioned on the respective cylinder head (2) in which a suction point (8a) is positioned, through which the lubricating oil is extracted from the chain case (24) and from an adjacent cylinder head section. Internal combustion engine according to one of the preceding claims, characterized in that at least one oil / air separator (11) is provided in the oil collection container (5), into which the lubricating oil drawn from the respective cylinder head (2) and / or the chain case (24) is conveyed before the lubricating oil flows back into the oil collection container (5). Internal combustion engine according to one of the preceding claims, characterized in that the oil pump (4) is attached to a lower flange surface of the crankcase facing the oil collection tank (5). Internal combustion engine according to one of the preceding claims, characterized in that the oil pump (4) is positioned inside the oil collection container (5). Internal combustion engine according to one of the preceding claims, characterized in that one or more suction points are additionally arranged in an intermediate section between the second end section (20) and the first end section (21) of the cylinder head.

Images