Cylinder head structure of an internal combustion engine

Abstract

To form an oil filter attachment hole 61 in a cylinder head 1 in a direction inclining relative to an upper surface of the cylinder head 1 and improve flexibility of the layout of an oil passage.SOLUTION: A cylinder head 1 includes hydraulic pressure lash adjusters at the intake side and the exhaust side. The cylinder head 1 has an oil storage part 46 at an upper surface center part of the cylinder head 1 covered with a cam carrier 2 and has an exhaust side oil passage 51 reaching an oil gallery 42 for the exhaust side lash adjuster. An inlet side portion of the exhaust side oil passage 51 is formed as an oil filter attachment hole 61 having a large diameter and attached with a cylindrical oil filter. A side surface 46a of the oil storage part 46 is formed by a flat surface which is orthogonal to a center axis of the oil filter attachment hole 61 and facilitates machine work of the oil filter attachment hole 61.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This invention relates to a cylinder head structure of an internal combustion engine in which an oil filter is loaded into an oil filter mounting hole of a cylinder head for a hydraulic lash adjuster or the like.

Background Art

[0002] For example, in a valve operating mechanism of an intake valve or an exhaust valve of an internal combustion engine, a hydraulic lash adjuster is known for automatically adjusting the valve clearance to zero. In a cylinder head provided with a hydraulic device such as this hydraulic lash adjuster, an oil passage is provided inside the cylinder head to supply oil to the hydraulic device. And, in order to prevent foreign matter from entering the hydraulic device, an oil filter mounting hole with an enlarged diameter is formed in a part of the oil passage, and a configuration in which an oil filter is loaded into this oil filter mounting hole is often adopted.

[0003] Patent Document 1 discloses a configuration in which an oil filter mounting hole is formed vertically on the upper surface of a cylinder head and a cylindrical oil filter is loaded.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As disclosed in Patent Document 1, oil filter mounting holes for housing cylindrical oil filters are generally formed by machining such as drilling, and for ease of machining, they are often provided perpendicular to the upper surface of the cylinder head. As a result, there is less freedom in designing the oil passages in the cylinder head, and the layout of the oil passages is restricted. If an attempt is made to machine an oil filter mounting hole on the upper surface of the cylinder head at an angle to that surface, the machining tool will strike the upper surface of the cylinder head at an angle, causing the machining tool to bend and reducing machining accuracy. [Means for solving the problem]

[0006] This invention is Cylinder head and, An oil filter mounting hole is provided on the upper surface of this cylinder head in a direction inclined with respect to this upper surface, The oil filter is installed in this oil filter mounting hole, A cylinder head structure for an internal combustion engine, comprising: the above oil A recess, larger than the aforementioned opening, is provided on the upper surface of the cylinder head so as to face the opening of the filter mounting hole. The wall surface of the recess through which the above-mentioned inlet opens is a plane perpendicular to the central axis of the oil filter mounting hole. This recess is covered by a cover member attached to the top surface of the cylinder head. [Effects of the Invention]

[0007] In this invention, since the oil filter mounting hole is machined in an inclined direction within the recess, it becomes easier to suppress uneven contact of the machining tool without being restricted by the angle with respect to the cylinder head top surface. By forming the oil filter mounting hole in an inclined direction with respect to the cylinder head top surface in this way, the degree of freedom in designing the oil passage is improved. [Brief explanation of the drawing]

[0008] [Figure 1] Front view of a cylinder head with a cam carrier. [Figure 2]Cross-sectional view of a cylinder head equipped with a cam carrier. [Figure 3] A cross-sectional view along the cross-section near the front end of the cylinder head. [Figure 4] A magnified view of the area around the oil filter mounting hole, where the oil filter is located. [Figure 5] Diagram illustrating the valve train mechanism. [Modes for carrying out the invention]

[0009] An embodiment of this invention will now be described in detail with reference to the drawings. Figure 1 is a front view showing the cylinder head 1 of an internal combustion engine according to this invention together with the cam carrier 2. The cylinder head 1 is integrally cast using a metal material, such as an aluminum alloy, and is mounted on the upper surface of the cylinder block 3. The internal combustion engine of this embodiment is a three-cylinder in-line spark-ignition internal combustion engine, a so-called gasoline engine, which is mounted in a so-called transverse position at the front of the vehicle. When mounted on the vehicle, the cylinder center axis is generally vertical, and therefore Figure 1 generally corresponds to the position when mounted on the vehicle.

[0010] Furthermore, the internal combustion engine of the embodiment has a pent-roof type combustion chamber equipped with a spark plug and a fuel injection valve in the center of the combustion chamber, and each cylinder is equipped with a pair of intake valves and a pair of exhaust valves.

[0011] The cylinder head 1 includes an intake camshaft 5 for the intake valve and an exhaust camshaft 6 for the exhaust valve. The cam carrier 2 is configured as a cover that covers the upper opening of the cylinder head 1 and is joined and fixed to the upper surface of the cylinder head 1 via a suitable sealing member such as a liquid gasket. The cam carrier 2 has an intake-side camshaft bearing portion 11 and an exhaust-side camshaft bearing portion 12 that are approximately semicircular in shape and extend downwards, and rotatably supports the intake camshaft 5 and exhaust camshaft 6, respectively, between these camshaft bearing portions 11 and 12 and cam brackets 13 and 14 that are mounted opposite to them.

[0012] As shown in Figure 1, the intake camshaft 5 is positioned relatively lower than the exhaust camshaft 6 in terms of height along the cylinder's central axis. Correspondingly, the height of the upper edge portion of the cam carrier 2 covering the top of each camshaft 5 and 6 is also configured so that the intake camshaft 5 side is lower than the exhaust camshaft 6 side. In one embodiment, the internal combustion engine is mounted in the engine compartment at the front of the vehicle with the intake camshaft 5 side at the front of the vehicle and the exhaust camshaft 6 side at the rear of the vehicle. Therefore, the clearance between the engine and the vehicle's engine hood (shown by the dashed line L), which is inclined so that the front end is at a lower position, is appropriate for both the intake camshaft 5 side and the exhaust camshaft 6 side.

[0013] Figure 2 is a cross-sectional view of the cylinder head 1 and cam carrier 2 shown in Figure 1, cut along a cross-section passing through the centers of the intake and exhaust valves. As mentioned above, it has a pent-roof type combustion chamber 31, to which the intake port 32 and exhaust port 33 are connected. In Figure 2, the valve train is not shown, but as is well known to those skilled in the art, cylindrical stem guides are attached to the stem guide mounting holes 34 and 35, respectively, and poppet valve type intake and exhaust valves are assembled together with valve springs.

[0014] Figure 5 is an explanatory diagram illustrating the valve train mechanism, which is not shown in Figure 2. A rocker arm 101, supported at one end by a hydraulic lash adjuster 36, swings due to the cam action of the intake camshaft 5, opening and closing the intake valve 103. Similarly, a rocker arm 102, supported at one end by a hydraulic lash adjuster 37, swings due to the cam action of the exhaust camshaft 6, opening and closing the exhaust valve 104. 105 represents the fuel injector, and 106 represents the spark plug. The hydraulic lash adjuster itself is a known configuration, so a detailed explanation is omitted, but it is roughly cylindrical in shape, extends to set the valve clearance to zero by an internal spring, and supports the reaction force during valve lift with oil filling the inside. Note that Figure 5 is an explanatory diagram of the mechanism and does not show the exact arrangement of each part.

[0015] In FIG. 2, line M1 indicates the center line of the valve stem of the intake valve, and line M2 indicates the center line of the valve stem of the exhaust valve. As shown in FIG. 2, the intake valve center line M1 passes inside in the width direction of the cylinder head 1 (the left - right direction in FIG. 2) from the center O1 of the intake camshaft 5. On the other hand, the exhaust valve center line M2 passes outside in the width direction of the cylinder head 1 from the center O2 of the exhaust camshaft 6.

[0016] Hydraulic lash adjusters 36 and 37 are provided for each of the intake valve and the exhaust valve. These hydraulic lash adjusters 36 and 37 are loaded into cylindrical lash adjuster mounting holes 38 and 39 provided in the cylinder head 1 and receive hydraulic supply.

[0017] The intake - side hydraulic lash adjuster 36 is located outside in the width direction of the cylinder head 1 from the intake valve center line M1, and in the illustrated example, it is arranged at a position generally directly below the intake camshaft 5. The exhaust - side hydraulic lash adjuster 37 is located inside in the width direction of the cylinder head 1 from the exhaust valve center line M2, and in the illustrated example, it is provided at a relatively higher position than the intake - side hydraulic lash adjuster 36.

[0018] For the entire in - line three - cylinder cylinder head 1, six intake - side hydraulic lash adjusters 36 and six exhaust - side hydraulic lash adjusters 37 are provided. The lash adjuster mounting holes 38 and 39 communicate with lash adjuster oil galleries 41 and 42 extending in the cylinder bank direction, respectively. The lash adjuster oil galleries 41 and 42 are, for example, drilled along the cylinder bank direction, and the ends of the lash adjuster oil galleries 41 and 42 depicted in FIG. 1 are blocked by plugs.

[0019] Next, the configuration of the main parts of the present invention will be described with reference to Figure 3. Figure 3 is a cross-sectional view of the cylinder head 1 near the front end. Figure 3 shows the layout of oil passages for supplying oil to the lash adjuster oil galleries 41 and 42. Similar to the lash adjuster oil galleries 41 and 42, these oil passages are constructed by a combination of straight drilling, and unnecessary open ends are closed with plugs. Note that some of the illustrated oil passages are in a different cross-section than those shown in Figure 3, and these parts are indicated by dashed lines in Figure 3.

[0020] An oil source pressure passage 45 extending vertically is formed approximately in the center of the width direction of the cylinder head 1, in other words, at a position between the intake camshaft 5 and the exhaust camshaft 6 when viewed in the direction of the cylinder axis. The lower end of this oil source pressure passage 45 communicates with the main oil gallery (not shown) of the cylinder block 3. Therefore, oil pressurized by the oil pump is supplied to this oil source pressure passage 45.

[0021] The upper end of the oil pressure passage 45 opens to the lower surface of an oil reservoir 46 formed on the upper part of the cylinder head 1. The oil reservoir 46 is formed as a bathtub-shaped recess at the joint surface with the cam carrier 2 at a position between the intake camshaft 5 and the exhaust camshaft 6, and is formed as a closed space by being covered by the lower surface of the cam carrier 2. The joint surface 47 between the cylinder head 1 and the cam carrier 2 around the oil reservoir 46 is sealed by a suitable sealing member such as the liquid gasket described above. This oil reservoir 46 corresponds to the "recess" in the claim.

[0022] As shown in Figure 3, the side surface 46a of the oil reservoir 46 on the exhaust camshaft 6 side is formed as an inclined surface, and one end of the exhaust-side oil passage 51 opens in the center of this side surface 46a. The exhaust-side oil passage 51 is formed in a straight line inclined at, for example, about 40 to 50° with respect to the joint surface 47 (in other words, the upper surface of the cylinder head 1), and its tip communicates with the exhaust-side lash adjuster oil gallery 42. In other words, oil is supplied to the exhaust-side lash adjuster mounting hole 39 from the oil reservoir 46 via the exhaust-side oil passage 51 and the lash adjuster oil gallery 42.

[0023] The inlet portion of the exhaust-side oil passage 51, that is, the portion closer to the oil reservoir 46, is formed with a larger diameter than the downstream portion (the portion closer to the lash adjuster oil gallery 42), and is configured as a cylindrical oil filter mounting hole 61. This oil filter mounting hole 61 is aligned linearly with the downstream portion as part of the exhaust-side oil passage 51. Therefore, the central axis of the oil filter mounting hole 61 is inclined at approximately 40 to 50° with respect to the upper surface of the cylinder head 1. The inlet 61a of the oil filter mounting hole 61 faces the oil reservoir 46 and opens approximately in the center of the side surface 46a of the oil reservoir 46. In one embodiment, the side surface 46a of the oil reservoir 46 forms a plane perpendicular to the central axis of the oil filter mounting hole 61.

[0024] On the other hand, the cam carrier 2 has an internal cam carrier passage 52 formed by connecting multiple straight sections, which passes through the inside of the cam carrier 2 as part of the oil passage from the oil reservoir 46 to the intake-side lash adjuster oil gallery 41. An intake-side oil passage 53 is formed inside the cylinder head 1 so as to connect to the outlet of the internal cam carrier passage 52. Therefore, oil is supplied to the intake-side lash adjuster oil gallery 41 from the oil reservoir 46 via the internal cam carrier passage 52 and the intake-side oil passage 53.

[0025] Figure 4 is an enlarged view of the area around the oil filter mounting hole 61. As shown in Figure 4, an oil filter 62 for removing foreign matter is installed in the oil filter mounting hole 61. The oil filter 62 has a common configuration in which a mesh member such as wire mesh is supported by a skeleton-like bottomed cylindrical frame made of metal or hard synthetic resin. It is installed inside the oil filter mounting hole 61 by inserting it axially from the inlet 61a side of the oil filter mounting hole 61.

[0026] As described above, in the configuration of this embodiment, the oil filter mounting hole 61 is inclined with respect to the upper surface of the cylinder head 1 together with the exhaust oil passage 51. Therefore, the layout of the oil passage is simpler compared to, for example, the case where the oil filter mounting hole 61 is bent from the exhaust oil passage 51 and formed perpendicular to the upper surface of the cylinder head 1. In other words, the layout of the oil passage is not constrained as it is when the oil filter mounting hole 61 is formed perpendicular to the upper surface of the cylinder head 1.

[0027] Furthermore, a recess (oil reservoir 46) is provided so as to face the inlet 61a of the oil filter mounting hole 61, and as a result the oil filter mounting hole 61 is formed perpendicular to the side surface 46a, making machining with a drill or other processing tool easy. In addition, the provision of the recess (oil reservoir 46) also secures space for the processing tool, making machining easier.

[0028] Furthermore, when machining the oil filter mounting hole 61 linearly with a drill or the like along its central axis, it is desirable to set the size of the recess, i.e., the oil reservoir 46, such that when a virtual cylindrical surface equal to the diameter of the oil filter mounting hole 61 is extended along its central axis, it does not interfere with the opposite edge 46b (see Figure 4) of the oil reservoir 46. In the illustrated example, the virtual cylindrical surface is set so as not to interfere with the edge 46b, and therefore, when machining the oil filter mounting hole 61, linear machining that diagonally crosses the recess (oil reservoir 46) is possible.

[0029] Furthermore, in the above embodiment, the recess that is useful for machining the oil filter mounting hole 61 is ultimately used as the oil reservoir 46. Therefore, the recess does not remain as so-called dead space, and the miniaturization of the cylinder head 1 is not compromised. And, since the cam carrier 2 is used as a cover member, no other cover member is required.

[0030] Furthermore, as shown in Figure 4, the oil filter 62, with one end facing the oil reservoir 46, is positioned at an angle. This makes it easier for some foreign matter, such as metal powder, accumulated in the internal space of the oil filter 62 to spill out into the oil reservoir 46. As a result, complete clogging of the oil filter 62 is less likely to occur. As mentioned above, the tilt of the internal combustion engine when mounted in a vehicle is relatively small, and therefore, the inclination of the oil filter mounting hole 61 with respect to gravity when mounted in a vehicle is the same as shown in Figures 3 and 4.

[0031] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible. For example, the formation position and inclination angle of the oil filter mounting hole 61 can be in various forms. Furthermore, the cam carrier is not limited to a cover-like configuration as in the above embodiment, but may have at least one camshaft bearing portion. The camshaft may also be rotatably supported between the cylinder head 1 and the cam carrier.

[0032] Furthermore, while it is preferable that the angle between the central axis of the oil filter mounting hole 61 and the side surface 46a be perpendicular to each other as in the above embodiment, it is not necessarily limited to this, and any angle closer to a right angle than the inclination angle between the upper surface of the cylinder head 1 and the central axis of the oil filter mounting hole 61 will be advantageous for machining. [Explanation of symbols]

[0033] 1…Cylinder head 2…Cam Carrier 5, 6… Camshaft 36, 37... Hydraulic lash adjuster 41, 42... Oil gallery for lash adjusters 45… Oil source pressure passage 46… Oil reservoir 51... Exhaust side oil passage 61… Oil filter mounting hole 62… Oil filter

Claims

1. Cylinder head and, An oil filter mounting hole is provided on the upper surface of this cylinder head in a direction inclined with respect to this upper surface, The oil filter is installed in this oil filter mounting hole, A cylinder head structure for an internal combustion engine, comprising: A recess, larger than the opening, is provided on the upper surface of the cylinder head so as to face the opening of the oil filter mounting hole mentioned above. The wall surface of the recess through which the above-mentioned inlet opens is a plane perpendicular to the central axis of the oil filter mounting hole. This recess is covered by a cover member attached to the top surface of the cylinder head. Cylinder head structure of an internal combustion engine.

2. The above recess constitutes the oil reservoir. The cylinder head structure for an internal combustion engine according to claim 1.

3. The oil filter described above is cylindrical in shape. The cylinder head structure for an internal combustion engine according to claim 1.

4. The above-mentioned oil filter mounting hole is located in the oil passage leading to the hydraulic lash adjuster positioned in the cylinder head. The cylinder head structure for an internal combustion engine according to claim 1.

5. The above-mentioned cover member is a cam carrier fixed to the upper part of the cylinder head and supporting the camshaft. The recess that serves as the oil reservoir is covered by the lower surface of the cam carrier. The cylinder head structure for an internal combustion engine according to claim 2.

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