EP0918154B1 - Cylinder head for an internal combustion engine - Google Patents

Description

The invention relates to a cylinder head for an internal combustion engine according to the preamble of independent claim 1.

In the prior art, for example, in four-stroke engines, with an adjustable valve timing control device mounted at each end of the intake camshaft and exhaust camshaft, the inner EGR rate is attempted to increase toward greater overlap by controlling the intake valves and the exhaust valves to reduce fuel consumption also to reduce the NOx emissions or by later closing the intake and exhaust valves to reduce the pumping losses and thus to reduce fuel consumption.

According to the prior art in Fig. 9, a camshaft 105 is mounted on a integrally formed on a cylinder head body 101 bearing web 101 a, which with oil paths 136, 137 for the supply of oil (control oil) from a control valve 150 to an adjustable valve timing control device and an oil path 138 for the oil supply (lubricating oil) of the other, the camshaft 105 bearing bearing webs is provided so that the bearing land 101 a wide, and an overhang of the variable valve control device 110 of a cylinder head bolt 109 is large, which leads to the problem that the Engine was getting longer and bigger.

Further, in the one-piece cylinder head of the prior art, the problem is that many time-consuming and costly machining operations are necessary for incorporation of the various complicated oil paths.

From DE 39 43 727 A a cylinder head of the type mentioned is known.

Furthermore, from DE 41 35 377 A1 a hydraulic control device for rotating a camshaft of an internal combustion engine is known, wherein the control device is arranged at one end of the camshaft. Here, a hydraulic body with oil paths for the control device between the control device and the camshaft is arranged, whereby the overall size of the internal combustion engine is increased.

It is an object of the present invention to improve a cylinder head of the aforementioned type such that a shorter and thus smaller design of the internal combustion engine is made possible.

The above object is achieved by a cylinder head of the type mentioned, wherein at the end of the camshaft, an adjustable valve timing means is arranged, and a control valve of the variable valve timing means is provided on the bearing block, wherein the bearing block comprises all the control valve enclosing inlet / outlet oil paths.

The invention thereby causes each one end of the camshaft to be supported by the bearing block which is separate from the cylinder head, the block being mounted in the cylinder head so as to overlap the attachment member, for example a cap screw, in the cross-section, that the internal combustion engine , in the following also engine, with shorter length can be executed.

By arranging all the control valve enclosing oil paths in the bearing block, the formation of the oil paths is facilitated and reduces the number of operations for machining the cylinder head, so that labor and time can be saved.

According to an advantageous embodiment of the invention, the bearing block is preferably positioned with two pins in the cylinder head body, wherein the bearing block is attached to the cylinder head body together with a camshaft cap by means of a camshaft cap mounting bolt. As a result, the bearing block can be mounted exactly in the cylinder head, without this would result in a larger increase in the number of parts.

If according to a further embodiment of the invention, the uppermost part of the control valve is exposed protruding beyond the head cover and sealed all around with sealing means, then this allows easy wiring of the control valve from above the cylinder head cover.

Further advantageous embodiments of the invention are specified in the subclaims.

Fig. 1

eine Detaildarstellung des Querschnitts eines Zylinderkopfes für einen Motor,

Fig. 2

eine Querschnittsdarstellung der am Ende des Zylinderkopfes sitzenden verstellbaren Ventilzeitsteuervorrichtung,

Fig. 3

eine Querschnittsdarstellung entlang der Linie A-A aus Fig. 2

Fig. 4

eine Querschnittsdarstellung entlang der Linie B-B aus Fig. 2,

Fig. 5

einen seitlichen Querschnitt einer verstellbaren Ventilzeitsteuervorrichtung,

Fig. 6

eine Querschnittsdarstellung zur Verdeutlichung des inneren Aufbaues der verstellbaren Ventilzeitsteuervorrichtung,

Fig. 7

eine schematische Darstellung des Ölzufuhrsystems für die verstellbare Ventilzeitsteuervorrichtung,

Fig. 8

eine Querschnittsdarstellung einer weiteren Möglichkeit zur Anordnung der Ölfilter, und

Fig. 9

eine Querschnittsdarstellung des Bereichs der verstellbaren Ventilzeitsteuervorrichtung eines Motorzylinderkopfes nach dem Stand der Technik.

In the following the invention will now be explained with reference to embodiments shown in the drawing. The drawing shows in

Fig. 1

a detailed representation of the cross section of a cylinder head for a motor,

Fig. 2

a cross-sectional view of the seated at the end of the cylinder head adjustable valve timing control device,

Fig. 3

a cross-sectional view along the line AA of FIG. 2

Fig. 4

a cross-sectional view taken along the line BB of Fig. 2,

Fig. 5

a side cross-section of an adjustable valve timing control device,

Fig. 6

a cross-sectional view illustrating the internal structure of the variable valve timing control device,

Fig. 7

a schematic representation of the oil supply system for the variable valve timing control device,

Fig. 8

a cross-sectional view of another way to arrange the oil filter, and

Fig. 9

a cross-sectional view of the range of the adjustable valve timing control device of a motor cylinder head according to the prior art.

In the internal combustion engine from which the invention is based, it is a multi-cylinder four-stroke engine, the cylinder head body 1 according to FIG. 1 per cylinder has openings for two inlet valves and two exhaust valves, wherein in the middle of the area between these intake valve 2 and exhaust valve holes 3 spark plug holes 4 are formed. Furthermore, bearing portions 1 a and 1 b, which support an intake camshaft 5 or exhaust camshaft 6 shown in FIG. 2, are located on the upper side of the cylinder head 1 between the two intake valve bores and the two exhaust valve bores. Into the intake valve bores 2 and exhaust valve bores 3 formed in the cylinder head 1 sit the intake valves (not shown), while in the plug bores 4 the spark plugs (not shown) are screwed in so that their electrodes protrude into the combustion chamber (not shown) of each cylinder formed in the cylinder head.

Here, the embodiment embodying the engine as shown in Fig. 2, respectively at one end of the intake camshaft 5 and the exhaust camshaft 6, an adjustable valve timing control device 10, respectively. 20; by this adjustable valve timing control device 10, respectively. 20 will be the Timing of the opening / closing of the intake, not shown, respectively. Exhaust valves optimally adapted or regulated according to the operating condition of the engine.

As shown in Fig. 1, the cylinder head right and left (in the figure above and below) at the top of the front part at the side where the adjustable valve timing control device 10, 20 is mounted, provided with two planar mounting surfaces 1 c, each mounting surface 1 c with two internal threads 7 and pin holes 8 is provided. Furthermore, there are left and right (at the inlet and outlet side) in the vicinity of the front side of the cylinder head body 1, the screw holes 31 through which the fastening elements shown in Fig. 5, here cap screws 9 are inserted, wherein the cylinder head 1 by means of these screw holes 31 are inserted with cap screws 9 and a plurality of cap screws (not shown) inserted through other screw holes are mounted on the top of the cylinder block (not shown).

In this embodiment, as shown in FIGS. 2 to 5, on the mounting surface 1 c formed in the cylinder head, a bearing block 32 separate from the cylinder head 1 is mounted in such a manner that, viewed in cross section, the cap screw 9 (see FIG. 5), while at the upper side of the bearing block 32, bearing portions 32a, 32b (see Fig. 2 and Fig. 3) are formed to freely rotatably support the respective portions of the intake camshaft 5 and exhaust camshaft 6, respectively.

As mentioned, the intake camshaft 5 and the exhaust camshaft 6 are each freely rotatably supported by the bearing portions 32a, 32b formed in the block 32 at the end where they are provided with the variable valve timing controller 10, with their upper half being supported by one on the upper side is mounted by block 32 mounted camshaft cap 33, while the bearing block 32 by pins 34 (see Fig. 3 and 4) is positioned, which in the Holes 8 stuck, which are formed in the respective mounting surfaces 1 c of the cylinder head 1, wherein in FIG. 4 by means of the camshaft cap 33 and the bearing block 32 respectively piercing screw holes 33a, 32c going camshaft cap screws 35, which in the mounting surface 1 c of the Cylinder head 1 trained internal thread 7 is screwed, the bearing block 32 is screwed together with the camshaft cap 33 with the cylinder head 1.

The following is an explanation of the internal structure of the variable valve timing control apparatus 10 with reference to FIG. 6.

The variable valve timing control apparatus 10 has a boss plate 13 screwed together with a cover 12 by a screw 11 to the end of the intake camshaft 5, a housing 14 rotatable with respect to the guide plate 13 being disposed on the outer circumference of this guide plate 13, and an outer circumference the innermost part of this housing 14 on its inner circumference a chain pinion (helical gear or toothed ring) 14a is integrally formed.

In the housing 14 is a relative to the guide plate 13 freely slidably wedged piston member 15, wherein the space formed in the housing 14 is divided by the piston member 15 in oil chambers S1 and S2. Furthermore, a helical gear 15a is formed at one end of the piston member 15; and this helical gear 15a is engaged with the helical gear (sprocket) 14a formed on a part of the inner periphery of the housing 14. The piston member 15a is tensioned by an inserted between this and the guide plate 13 spring 16 to the outside.

On one of the two oil chambers S1 formed in the housing 14 of the adjustable valve timing control device 10, an oil path 17 formed in the guide plate 13 and the intake camshaft 5 opens, wherein this oil path 17 communicates with an oil groove 32d, 33b formed in the bearing block 32 and the camshaft cap 33, and with an oil path 36 formed in the bearing block 32.

Further, on the other oil chamber S2 formed in the housing 14, an oil path 18 formed of the guide plate 13 and intake camshaft 5 opens, this oil path 18 having an oil groove 5a formed on the outer circumference of the intake camshaft 5 and an oil path 37 (see FIG. Fig. 7) is in communication.

On the other hand, in the intake camshaft 5, an oil path 5b is formed in the axial direction, and its portion corresponding to the journal is provided with a plurality of radially-disposed oil holes 5c. The overlapping on the block 32 bearing journal portion of the intake camshaft 5 is provided at its entire outer periphery with a Ölzuführungsnut 5d, at this Ölzuführungsnut 38 formed in the bearing block 32 oil path 38 opens, said oil path 38 formed with the equally formed in the bearing block 32 oil passages 39, 40 communicates. A flange portion 5e, 5f formed on the outer circumference of the intake camshaft 5 is received by the end face of the block 32, the bearing block 32 acting as a thrust bearing which receives the thrust force caused by the intake camshaft 5.

Although the above explanation has been given to the structure of the intake-side variable valve timing control apparatus 10, as shown in FIG. 2, the exhaust-side variable valve timing control apparatus 20 is constructed in the same manner. In the illustrated in Fig. 2, outlet-side adjustable valve timing 20 thus corresponds to the reference numeral 21, the screw 11, 22, the cover 12, 23, the guide plate 13, 24, the housing 14, 25, the piston member 15, 26, the spring 16, 27, 28 the Oil routes 17,18 and S1, S2 the oil chambers.

On the other hand, as shown in Fig. 2, in the exhaust camshaft 6, an oil path 6b is formed in the axial direction, and its portion corresponding to the journal is provided with a plurality of radiatingly arranged oil holes 6c. The overlapping on the bearing block 32 bearing journal portion of the exhaust camshaft 6 is provided at its entire outer periphery with a Ölzuführungsnut 6d, at this Ölzuführungsnut 6d formed in the bearing block 32 oil path 48 opens, said oil path 48 formed with the equally formed in the bearing block 32 oil passages 39, 40 communicates. A flange portion 6e, 6f formed on the outer circumference of the exhaust camshaft 6 is received by the end face of the bearing block 32, and the bearing block 32 functions as the thrust bearing which receives the thrust force caused by the exhaust camshaft 6.

As shown in FIG. 2, an endless timing chain 41 is placed around the chain sprocket 14a, 24a formed integrally with the housing 14, 24 of the variable valve timing control device 10, 20 and a drive pinion not shown; and when the timing chain 41 is driven by a rotation transmitted from an unillustrated crankshaft sprocket to the drive sprocket, then the intake camshaft 5 and exhaust camshaft 6 are rotated by the rotation of the sprocket 14a, 24a, through which rotation the unillustrated intake valves and exhaust valves be opened and closed the appropriate timing to make the required gas exchange in all cylinders.

The following is an explanation of the oil supply to the variable valve timing control devices 10, 20 with reference to FIGS. 3 and 7.

Control valves 50, 51 are vertically mounted on the bearing block 32 for controlling the oil supply to the inlet and outlet side adjustable valve timings 10, 51, wherein according to FIG. 3, an upper part of the individual control valves 50, 51 formed by a cylinder head cover 42, round Opening 42a project outwardly, being sealed around with a sealant 53. Since now the upper part of the individual control valves 50, 51 protrudes through the cylinder head cover 42 to the outside, can be wired to the control valves 50, 51 leading lines in a simple manner above the cylinder head cover 42.

At the inlet side and at the outlet end of the cylinder head 1, the oil paths 43 are each formed vertically, wherein the oil paths 37 as shown in Fig. 7 with an outlet side of an oil pump 44 are in communication. Furthermore, the cylinder head 1 is provided on its upper side with round openings 1 d, which communicate with all oil passages 43, wherein in all round openings 1 d oil filter 45 are arranged, each oil filter 45 through the oppressive on him bearing block 32 in the round openings 1 d is held.

Fig. 8 shows another way of receiving the oil filter 45, wherein according to this figure at the bottom surface of the bearing block 32, a round opening 32 e is formed, wherein the oil filter 45 is received by the cavity, which from this round opening 32 e and the side formed of the cylinder head 1 round opening 1 d is formed, wherein the oil filter 45 can also be held by the pressing on him bearing block 32 in position.

Further, in the bearing block 32, the oil path 40 communicating with the round hole 1 d and the oil path 43 is formed in the vertical direction, and this oil path 40 communicates with the oil path 39 communicating with the two control valves 50, 51 in that, of the control valves 50, 51, the oil paths 36, 37 and the oil passages 46, 47 extend obliquely respectively toward the journal section 32, 32b. Furthermore, the oil paths 38, 48 branch off from the oil path 39 in order to lead oil (lubricating oil) to the bearing journals 32 a, 32 b of the block 32. In Fig. 7, 52 is an oil path (return path), which returns the oil in the oil pan, not shown.

The following is a functional explanation of the variable valve timing control device 10,20.

When the engine is started and a portion of its driving force causes the intake and exhaust camshafts to rotate, the intake and exhaust valves are opened and closed at a suitable timing to complete the required gas changes in all cylinders.

When the engine is started, however, the oil pump 44 is driven as shown in FIG. 7 of a part of its driving force, so that the standing at the outlet of the oil pump 44 under defined pressure oil through the formed in the cylinder head 1 oil path 42 and the oil filter 45 and the formed in the bearing block 32 oil path 40 into the oil path 39, a part of which from the oil passages 38, 48 of the oil grooves 5d, 6d of the intake-side and exhaust-side camshaft 5, 6 through the oil paths 5b, 6b of the intake-side and exhaust-side camshaft 5, 6 flows, wherein it lubricates the bearing journal area of the inlet and outlet side camshaft 5, 6 from the radially shaped oil holes 5c, 6c. The remainder of the oil flowing through the oil path 39 in the block 32 is directed into the control valves 50, 51.

The function of the control valves 50, 51 is controlled by an unillustrated electronic engine control unit (ECU) corresponding to an operating condition of the internal combustion engine, so that by switching the supply of oil to the variable valve timing devices 10, 20, the oil to the oil chamber S1 and S2, respectively Valve timing 10, 20 supplied and so the timing for the opening / closing of the intake / exhaust valves is advanced or retarded.

So if now from the control valves, the oil from the oil passages 36, 46 the Oil chambers S1 of the variable valve timings 10, 20 is supplied, or when it is supplied from the oil passages 37, 47 the oil chambers S2 of the variable valve timings 10, 20, then slides in the variable valve timings 10, 20, the piston member 15, 25 in the axial direction the guide plate 15a, 25a, so that the housing of the engaged in engagement with the helical gear 15a, 25a of this piston member 15, 25 helical gear (toothed ring) 14 a, 24 a relative to the guide plate 13, 23 and the intake / exhaust camshaft 5, 6 turns. Now, in the variable valve timing 10, 20, as the housing 14, 24 rotates relative to the intake / exhaust camshafts 5, 6, the relative position of the cams on the intake / exhaust camshaft and the opening / closing timing of the cam changes Inlet / exhaust valves are advanced / retarded so that in the various operating ranges, increased intake valve overlap with exhaust valves intensifies internal EGR thereby reducing fuel consumption and NOx emission, or retarding the intake and exhaust valves depending on the operating range Compression stroke incurred pumping losses and thus the fuel consumption can be reduced.

In the embodiment of the embodiment, in each case one end of the intake / exhaust camshaft 5, 6 is supported by the journal section 32a, 32b formed in the bearing block 32 which is separate from the cylinder head 1, FIG. 5 being such that this block 32 is thus located in the cylinder head 1, that it overlaps in cross-section over the cap screw 9, as shown in FIG. 5, the size of an overhang L of the adjustable valve timing 10, 20 of the cap screw 9 can be reduced by exactly the amount of this overlap, so that the internal combustion engine with reduced Overall length can be constructed smaller.

Further, the bearing block 32 is positioned with two pins 34 in the cylinder head 1, wherein the block 32 together with the camshaft cap 33 by means of Camshaft cap screw 35 is screwed to the cylinder head 1, so that the bearing block 32 can be mounted exactly in the cylinder head body 1, without this would entail a significant increase in the number of parts.

Further, on the bearing block 32, the control valves 50, 51 are mounted, and the oil paths 36-40, 46-48 including these control valves 50, 51 are formed in a block shape in the block 32, so that these oil paths 36-40, 46-48 are made simpler can be and accordingly reduce the number of operations for the processing of the cylinder head 1 and thus Arbeitszeit- and cost.

Further, in the embodiment of the embodiment, the oil filters 45 are mounted in the cylinder head 1, which are held in position by the bearing block 32, so that a rational arrangement of these oil filters 45 is possible and the number of machining operations for the cylinder head 1 can be reduced.

Claims (5)

1. Cylinder head for an internal combustion engine, comprising :

   - a cylinder head base member (1);

   - a camshaft (5, 6);

   - a securing member (9) for securing the cylinder head base member (1) to a cylinder block, and

   - a camshaft bearing consisting of a camshaft cover (33) which constitutes an upper part of the bearing, and a bearing block (32) which constitutes a lower part of the bearing, wherein the bearing block (32) is constructed separately from the cylinder head base member (1), is mounted on the cylinder head base member (1), and in the mounted position, viewed in cross-section, overlaps the securing member (9),

   characterised in that at the end of the camshaft (5, 6) is mounted an adjustable valve timing control device (10, 20), and a control valve (50, 51) of the adjustable valve timing control device (10, 20) is provided on the bearing block (32), the bearing block (32) comprising all the oil conduits (36-40, 46-48) which encompass the control valve (50, 51).
2. Cylinder head according to claim 1, characterised in that the bearing block (32) is positioned preferably with two pins (34) in the cylinder head base member (1), the bearing block (32) together with the camshaft cover (33) being mounted on the cylinder head base member (1) by means of a camshaft cover fixing bolt (35).
3. Cylinder head according to claim 1 or 2, characterised in that an upper part of the control valve (50, 51) protrudes outwards through a cylinder head cover (42) and is sealed all around by sealing means.
4. Cylinder head according to one of claims 1 to 3, characterised in that an oil filter (45) is provided in at least one oil conduit (43) formed in the cylinder head base member (1), and the oil filter is held in position by the bearing block (32) pressing on it.
5. Cylinder head according to one of claims 1 to 4, characterised in that the adjustable valve timing control device (10, 20) with the control valve (50, 51) is provided on an inlet camshaft (5) and an outlet camshaft (6).

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