WO1997040267A1 - Reciprocating internal combustion engine - Google Patents

Abstract

For a compact arrangement of a relatively large number of cylinders (Z1-Z8), the invention proposes that two rows of cylinders (R1, R2) be arranged relative to each other so as to form a V shape, with a third row (R3) situated between rows R1 and R2 and with a fourth row (R4) provided outside the V space between rows R1 and R2, the third and fourth rows (R3, R4) likewise forming a V shape between them and all cylinders (Z1-Z8) of the internal combustion engine working on one and the same crankshaft.

Description

 Reciprocating internal combustion engine

The invention relates to a reciprocating piston internal combustion engine having a plurality of rows of cylinders along two rows at an angle to one another according to the preamble of patent claim 1

A generic internal combustion engine is known from DE-Z MTZ Motortechnische Zeitschrift 52, 1991, No. 3, pages 100 ff. The so-called VR engine described there and produced by the registrants in large series has cylinders combined in two rows, these two rows Compared to known, V-shaped internal combustion engines with a comparatively large fork angle, this cylinder arrangement offers the advantage that only a single cylinder crankcase with all the cylinders then combined in one block and only one cylinder head common to all cylinders is required Offset of the two rows of cylinders in the longitudinal direction to each other, the overall length of such a VR engine with 6 cylinders, for example, is only marginally greater than that of a conventional 4-cylinder in-line engine is claimed

The cylinder banks of this engine have a fork angle of 15 ° to each other and the three cylinder axes of each row of cylinders lie in a common plane, which intersect at a distance of 12.5 mm below the crankshaft.This closed crank crank leads to a further shortening of the engine. With regard to the geometry of the crank mechanism and the crankshaft cranking positions used and the firing sequences, reference is made to DE-Z MTZ, Motortechnische Zeitschrift 51, 1990, No. 10, which deals in detail with this VR engine concept and also suggestions regarding the use of one , two or three camshafts in the common cylinder head for actuating two or four valves per combustion chamber In order to achieve the most compact possible cylinder arrangement, in addition to the VR concept already cited, there have already been other approaches

For example, a 16-cylinder engine with an H-shaped cylinder arrangement has become known from the DE book Air-Cooled Vehicle Engines, Mackerle, Jehlicka, Moebus, Franksche Verlagbuchhandlung Stuttgart, page 509. A compact arrangement is achieved here by arranging two 8-cylinder drums one above the other Boxer internal combustion engines achieved These each work on their own crankshaft, which, coupled to one another, operate a single-shaft output.The two opposite, 4-cylinder rows have no longitudinal offset from each other since the two connecting rods from opposite cylinders through the use of a connecting rod on a common crank pin Crankshaft work

From the same source, pages 515 ff, a further, compact arrangement in X-shape is known. With respect to a vertical plane, two rows of cylinders are arranged in a V-shape with respect to one another, each of which is arranged on a crank mechanism with a common crankshaft work, that is, all cylinder long axes intersect the central crankshaft's longitudinal axis. The crankshaft has only four crankings, since a main connecting rod with three secondary connecting rods works on each of these crank pins, that is to say the four rows of cylinders have no longitudinal offset to one another.

A further compact arrangement of several cylinders of an internal combustion engine in a W shape is known from DE-Z Sportauto, March 1988, No. 3, pages 90 ff. This comparatively wide, but short cylinder arrangement has three 4-cylinder rows of one of which lies in the middle in a vertical plane, while the other two are arranged in a V-shape, with the first row as a bisector. The three rows have a longitudinal offset relative to one another, since three cylinders each work with their connecting rods lying next to one another on a common crank pin of the crankshaft. The problem with such an arrangement is the uniform supply of the combustion chambers assigned to the cylinders with fresh mixture and the removal of the combustion gases, since there are only inlet ducts for two cylinder rows in the V-space on one side of the horizontal plane, while in on the other side In this V-space, the intake ports assigned to one of the rows of cylinders and the exhaust ports of the other row of cylinders must be arranged.

Ultimately, it is known from DE-Z MTZ Motortechnische Zeitschrift 1940, Issue 2, pages 52 and 53, two V-shaped internal combustion engines to a double-V engine to summarize that the bisectors of the V-rows, each with a cylinder angle of 60 °, form an angle of 90 "to each other. The two rows of a V-space each work on their own crankshaft.

The invention is based on the object of developing a generic reciprocating internal combustion engine with a plurality of cylinders which are at an angle to one another and have a longitudinal offset from one another in such a way that a compact arrangement of a comparatively large number of cylinders is made possible by taking up as little installation space as possible. At the same time, a proper supply of fresh air or the discharge of the exhaust gases as well as a perfect drive of the gas exchange valves providing the gas exchange are to be ensured.

This object is achieved with the features of claim 1. Advantageous refinements of the invention are specified in the dependent claims.

The invention solves this problem in a generic internal combustion engine by an arrangement of two further, also V-shaped rows of cylinders, one of these rows of cylinders being arranged in the V-space between the first and second rows and the further, fourth row outside this V-space lies, whereby the cylinders of all rows work on a common crankshaft. With a suitable choice of the angles lying between the individual rows, it is possible in this way to achieve a compact arrangement of the cylinders, whereby in particular the overall length in the direction of the crankshaft axis can be kept short. The even number of rows of cylinders also ensures a symmetrical arrangement of lines for the air supply and for exhaust gases.

Furthermore, this provides the basis for a modular construction of a series of internal combustion engines of the same type with different numbers of cylinders while maintaining the fundamentally compact arrangement and while maintaining existing lines. Both even and odd number of cylinders can be used in each row.

In an advantageous embodiment, in order to achieve a comparatively simple structure, it is provided that the additional, third and fourth rows have a longitudinal offset from one another and from the first two rows of cylinders. In this way, uniform connecting rods can be used for all cylinders while avoiding comparatively complicated and expensive fork connecting rods. It is preferably provided that the fork angle formed between the first and second row of cylinders and that between the third and fourth row of cylinders is identical in each case and that the V-spaces formed by this fork angle are rotated relative to one another by a certain cylinder angle chosen so that the first and third or second and fourth rows at this angle to each other are mirror-symmetrical with respect to the other two rows to a central plane of the internal combustion engine receiving the crankshaft. Assuming a perpendicular central plane, V is thus obtained on both sides of this plane Shaped rows of cylinders arranged with respect to one another, the cylinder angle within these V-shaped rows being chosen to be comparatively small

In a further preferred embodiment of the invention it is provided according to claim 4 that the crank mechanism of this internal combustion engine is designed to be locked, that is to say the cylinder axes of the two rows on one side of the central plane intersect when the central plane is arranged vertically below this and on the opposite side further shortening of the internal combustion engine is possible by pushing the cylinders assigned to the two rows into each other

In order to achieve even ignition spacing even with a different number of cylinders, for example two cylinders per cylinder row, i.e. a total of 8 cylinders, a crank star with 4 crankings resulting from the image of the crankshaft can be provided, each crank having two offset bearings for connecting rods this common, offset cranking each work the connecting rods of two cylinders of the first and third or second and fourth rows which are offset by the fork angle

Alternatively, for example, to achieve a 10-cylinder internal combustion engine, two of the cylinder rows each have three cylinders and the other two have two cylinders

In order to use the same parts as possible and to achieve a symmetrical arrangement, it is preferably provided that the rows with the larger number of cylinders are offset from one another by the fork angle

In a further advantageous embodiment, it can be provided that the rows lying on both sides of the central plane and offset by the cylinder angle from one another are each combined to form a coherent cylinder block which can be covered by a cylinder head common to these two rows In order to achieve an arrangement that is optimal in terms of installation space, for example the control drive of the internal combustion engine, the two combined cylinder rows can be designed identically on each side of the central plane, which means that further advantageous effects in terms of component expenditure, assembly, etc. can be achieved.

Further advantages of the invention result from the exemplary embodiment explained in more detail below with reference to a drawing. Show it:

Figure 1 is a schematic plan view of an internal combustion engine according to the invention, Figure 2 is a schematic side view of Figure 1 of the crank mechanism and Figure 3 shows a cross section through an internal combustion engine.

A reciprocating piston internal combustion engine, hereinafter referred to only as an internal combustion engine, has a total of four rows R1, R2, R3, R4 of cylinders, two of these rows R1, R3 and R2, R 4 being arranged on one of the two sides S1, S2 of a central plane ME ¬ are arranged, which receives a crankshaft axis 1.

The row R1 assigned to the side S1 and the row R2 assigned to the side S2 are at a fork angle 57 in a V-shape to one another and thus define a first V-space VI between them

Analogously, the two further cylinder rows R3 and R4 are assigned to the sides S1 and S2 and are at a fork angle 52, defining another V-space V2, to one another. The third row R3 is thus in the first V-space VI, while the fourth row R4 is arranged outside this space V1.

The rows R1 and R3 lying on the side S1 are combined to form a group G1, cylinder axes ZR1 of the first row and cylinder axes ZR3 of the third row in turn being at a V-shaped cylinder angle αG1. The size of the fork angles 57 and 52 is chosen identically, as is the size of the cylinder angles αG1 and αG2, the entire arrangement with respect to the central plane ME being such that the groups G1 and G2 are each symmetrical to this central plane ME and thereby the Rows R1, R3 and R2, R4 of these groups G1 and G2 are each arranged mirror-symmetrically to this plane ME.

Within groups G1 and G2, cylinder axes ZR1 and ZR3 or ZR2 and ZR4 have an identical row offset 2 to one another along crankshaft axis 1. The two groups G1 and G2 in turn have a group offset 3 along this crankshaft axis 1.

The cylinder axes ZR1 to ZR4 thus each lie in one of four sectional planes SE1 to SE4 formed perpendicular to the central plane ME.

The interaction of the individual cylinders in the crank mechanism is explained using an 8-cylinder version of the internal combustion engine. According to FIG. 1, the cylinders Z1 and Z3 are assigned to the first row R1, the cylinders Z2 and Z4 to the third row R3, the cylinders Z5 and Z7 to the second row R2 and the cylinders Z6 and Z8 to the fourth row R4. A crankshaft 4 of the internal combustion engine has a total of four crankings 5, 6, 7, 8 and is supported in a total of five main bearings 9 of a crankcase 10. To achieve a uniform and comfortable firing order, two cylinders each work on one of the cranks by means of the connecting rods 11 assigned to them, the two conrod bearings 12, 13 of a crank having an offset by a difference angle Δφ. The cylinders, which are staggered relative to each other by the group offset 3 and are assigned to one of the V-spaces V1 or V2, work on one of the offsets. Thus, the connecting rods 11 of the cylinders Z1 and Z5 with the crank 5, the cylinders Z2 and Z6 with the crank 6, the cylinders Z3 and Z7 with the crank 7 and the cylinders Z4 and Z8 with the crank 8. As can be seen from FIG. 2, on the right, the connecting rods 11 of the cylinders Z1 and Z5 lying in the sectional planes SE1 and SE2 are spaced apart from one another by the offset 3 in the crank 5. Between the connecting rods 11 of cylinders Z5 and Z6 lying in the sectional plane SE2 and SE4 there is the row offset 2, usually referred to as the cylinder spacing.

The crank mechanism of the internal combustion engine is designed to be limited, that is to say the cylinder axes ZR1, ZR3 or ZR2, ZR4, which are mutually spaced about the cylinder angle αG1 or αG2, do not intersect with the crankshaft axis 1 Intersection SP1 of the first group G1 on the side S2 on the side of the transverse plane QE facing away from the rows R1 and R3. For this purpose, another intersection point SP2 of the second group G2 lies in mirror image with respect to the center plane ME.

Due to the cranking of the crank mechanism, the maximum extension positions of the connecting rods 11 at top and bottom dead center OT and UT do not coincide with the respective cylinder axis ZR. If the crank angle φ occurring during the rotation of the crankshaft 4 is counted by the crankshaft axis 1, based on an unrestricted crank drive from a parallel 13 to the cylinder axis ZR, then TDC and LDC are achieved with a crank angle offset of φ *. Due to the location of the intersections SP1 and SP2 with respect the transverse plane QE on the side facing away from the groups G1 or G2 produces a positive or negative setting, so that the bottom dead center UT follows the top dead center OT after more or less than 180 "crank angle φ.

The selected setting enables the cylinders within the groups G1 and G2 to be moved closer together so that the respective cylinders of these groups G1 and G2 can be cast together in a common cylinder block 15 and 16, respectively. These are each covered by a cylinder head 17 or 18 common to the two cylinder rows of a group.

The interaction of the previously explained 8-cylinder arrangement will be briefly explained using a numerical example. The fork angles 81 and 82 are 72 °, the cylinder angles αG1 and αG2 each 15 °. Because of the symmetrical arrangement with respect to the center plane ME, the fork angle 57 and 52 is also established with respect to the bisector 19 of the cylinder angles αG1 and αG2. Because of the four crankings 5 to 8 lying in two planes, an ignition sequence between the individual cylinders occurs at a distance of 90 ° crank angle φ. With a selected firing sequence in the sequence Z1-Z5-Z4-Z8-Z6-Z3-Z7-Z2, the arrows P1 to P8 assigned to the cylinders Z1 to Z8 in FIG. 2, shown on the left, are shown on the left Positions of the ignition points. While between cylinders Z1 and Z5, which work on a common crank 5, there would be a harmonic firing distance of 90 °, a difference angle of Δφ of 18 ° arises due to the fork angle 5 of 72 °, in which case when the Cylinder Z1 lagging at top dead center TDC of cylinder Z5 by the difference angle Δφ of 18 °. For the cylinder Z4 following the cylinder 5 in the firing sequence, a crank angle φ of approximately 140 ° is established as a result of the selected fork angle 5, the cylinder angle αG and the crank angle offset φ *. At the time of ignition of the cylinder Z4, the cylinder Z8 working on the same offset 8 again lags by the difference angle Δφ of 18 °.

Alternatively, in the case of a 10-cylinder arrangement, the offset within the individual crankings 5 to 8 can be dispensed with. The rows R3 and R4 are each assigned three cylinders, while the rows R1 and R2 each carry two cylinders. While the previously described mirror-image arrangement of the mentioned angular positions with respect to the center plane ME is retained, the arrangement of the rows is not mirror-image, since the three-cylinder row R3 lying on the side S1 is first followed by a two-cylinder row R2 on the side S2. Assuming that this is also a 4-stroke internal combustion engine, with a fork angle of 72 ° there is no need to offset within the 5 crankings. In order to achieve an even firing interval of 72 ° crank angle φ, the 5 crankings are in a total of 5 levels.

In a further alternative with a total of 12-cylinder arrangement, an ignition sequence with a crank angle φ of 60 ° occurs at a fork angle of 72 ° of a 4-stroke engine. The crankshaft 4 carries a total of six offsets provided with an offset by the difference angle Δφ. Assuming the same fork angle δ of 72 ° and the ignition distance of 60 °, a differential angle Δφ of 12 ° is established at each crank. Here, for example, according to FIG. 1, a cylinder Z'1 of the first row R1 works with a seventh cylinder Z'7 of the row R2 on a crank, whereby after the ignition of Z'1 in TDC, the cylinder Z'7 by the difference angle Δφ of Leading 12 °.

A flywheel 25 is assigned to the crankshaft 4 on the output side. Adjacent to this is a chain drive for driving camshafts 27 and 28 of group G1 and camshafts 29 and 30 of group G2. These operate via cams 31 and 32 designed as lift valves inlet valves 33 and outlet valves 34 with the interposition of roller rocker arms 35, four lift valves being assigned to each cylinder Z1 to Z8.

The symmetrical and four-row arrangement of the cylinders enables the formation of completely symmetrical and similarly designed breathing paths for supplying fresh air and a symmetrical arrangement of exhaust pipes.

An air intake system for ventilating the combustion chambers 40 of the internal combustion engine is essentially symmetrical to the central plane ME and is provided with collecting volumes 37 and 38 formed above the groups G1 and G2. Combustion air is fed via suction pipes 41 from the above-mentioned collecting volumes 37, 38 to inlet channels 41, all inlet channels 41 of a group G1 or G2 each opening into a flange 42 which is formed on the row R3 or R2 facing the central plane ME. All outlet channels 43 of the respective group G1 or G2 are led to flanges 44 of the rows R1 and R4, which are external to the central plane ME.

The cylinder blocks 15 and 16 are formed in one piece and with the same material as the crankcase 10, the outer walls 45 of which are drawn in the region of the crankshaft axis 1 across the transverse plane QE.

Claims

claims 1. reciprocating internal combustion engine with a first and a second V-shaped mutually facing row (R1 and R2) of cylinders, which along one of the rows (R1, R2) with respect to the cylinders of the other row (R2, R1) in the longitudinal direction of the The internal combustion engine is arranged offset and connected to a common crankshaft (4), characterized by two further, third and fourth rows (R3 and R4) of cylinders, which are in a V-shape with respect to one another, one (R3) of which is in the V-space (V1) between the first and second row (R1 and R2) and the other (R4) is arranged outside this V-space (V1) and all cylinders (Z1 to Z8) are connected to one crankshaft (4). 2. Internal combustion engine according to claim 1, characterized in that the third and fourth rows (R3 and R4) an offset (3) to each other and the third row (R3) to the first row (R1) and the fourth row (R4) to the second row (R2) each have an offset (2) to each other. 3. Internal combustion engine according to claim 2, characterized in that the fork angles (57 and 62) formed between the first and second rows (R1 and R2) and the third and fourth rows (R3 and R4) are identical in size and that the fork angles formed by these (57, 52; V spaces (V1, V2) formed are arranged rotated relative to one another by a cylinder angle (αG1, αG2) such that the first and third rows (R1 and R3) which are at this cylinder angle (αG1) are mirror-symmetrical with respect to the third and fourth row (R3 and R4) lie to a central plane (ME) of the internal combustion engine which receives the crankshaft (4). 4. Internal combustion engine according to claim 3, characterized in that the Zylin¬ derachsen (ZR1, ZR3 and ZR2, ZR4) each on one side (S1 and S2) of the central plane (ME) arranged rows (R1, R3 and R2, R4) intersect, the intersections (SP1 and SP2) with respect to a transverse plane (QE) running perpendicular to the central plane (ME) through the crankshaft axis (1) on the transverse plane Rows (R1 to R4) facing away from this transverse plane (QE) and on the opposite side (S2 and S1) of the central plane (ME). 5. Internal combustion engine according to claim 3 or 4, characterized in that the number of cylinders is an integer multiple of the number of rows of cylinders and in each case two by the fork angle (δ1, 52) staggered cylinders (Z1 and Z5) of the first and second rows (R1 and R2) or (Z2 and Z6) of the third and fourth rows (R3 and R4) are connected to a common, offset crank (5 or 6) of the crankshaft (4). 6. Internal combustion engine according to claim 3 or 4, characterized in that at least two (R3, R4) of the rows have an identical, larger number of cylinders than the other two rows (R1, R2). 7. Internal combustion engine according to claim 6, characterized in that the rows (R3, R4) with the larger number by the fork angle (57, δ error! 8. Internal combustion engine according to one or more of the preceding claims 1 to 7, characterized in that between the first and the third or the second and the fourth row (R1 and R3 or R2 and R4) formed cylinder angle (αG1 or α .G2) is selected to be comparatively small, so that the cylinders (Z1 to Z4) of the rows (R1 and R3) combined to form a first group (G1) are combined to form a one-piece cylinder block (15) and the other cylinders (Z5 to Z8 ) are combined to form the same cylinder block (16) of a second group (G2). 9. Internal combustion engine according to one or more of the preceding claims 1 to 8, characterized in that the fork bracket (57 or 32) formed between the first and second row (R1 and R2) or the third and fourth row (R3 and R4) is between 60 ° and 90 °, preferably 72 °. 10. Internal combustion engine according to claim 9, characterized in that between the cylinders of the first row (R1) and the third row (R3) or the second row (R2) and the fourth row (R4) occurring cylinder angles (αG1 or αG2) between 10 ° and 20 °, preferably 15 ° Internal combustion engine according to claim 5 or 6, characterized in that the cylinder axes (ZR1, ZR2) of the cylinders (Z1, Z5) working on a common crank (5) of the crankshaft (4) in section perpendicular to the central plane (ME) planes (SE1, SE2) are arranged lying, which are spaced apart in the direction of the crankshaft axis (1) by the group offset (3) Internal combustion engine according to claim 5 or 6, characterized in that the cylinder axes (ZR2, ZR4) of the cylinders (Z5, Z6) each working on a crank (5, 6) of the crankshaft (4) are perpendicular to the central plane (ME ) running sectional planes (SE2, SE4) are arranged lying, which are spaced apart by the row offset (2)