internal combustion engine

Abstract

To provide an internal combustion engine capable of protecting a portion exposed to the outside of a hydraulic control valve from foreign matter such as scattering stones coming from below.SOLUTION: An exhaust side cylinder part 24 is formed below and adjacent to a bulging part 21. The other axial end part 24D of the exhaust side cylinder part 24 is arranged below one axial end part 24C of the exhaust side cylinder part 24. A chain case 20 has a connection rib 32 that connects the other axial end part 24D of the exhaust side cylinder part 24 and the bulging part 21 on the side of the other axial end part 24D of the exhaust side cylinder portion 24.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an internal combustion engine. [Background technology]

[0002] Patent Document 1 describes a solenoid valve arrangement structure including a first solenoid valve that controls hydraulic oil supplied to an intake valve phase changing means that changes the rotational phase of an intake valve camshaft, and a second solenoid valve that controls hydraulic oil supplied to an exhaust valve phase changing means that changes the rotational phase of an exhaust valve camshaft. In Patent Document 1, the first solenoid valve and the second solenoid valve are provided on a timing chain cover that is located at the end of the engine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-118497 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology described in Patent Document 1, the first solenoid valve and the second solenoid valve are positioned to protrude outward from the end of the timing chain cover, and there was a risk that the exposed parts of the first solenoid valve or the second solenoid valve would be damaged by collision with foreign objects such as flying stones from the road surface.

[0005] The present invention has been made in light of the above-mentioned circumstances, and aims to provide an internal combustion engine that can protect the exposed portion of the hydraulic control valve from foreign objects such as flying stones that fly in from below. [Means for solving the problem]

[0006] The present invention relates to an internal combustion engine that includes a variable valve timing mechanism around which a timing chain is wound, a hydraulic control valve that controls hydraulic oil supplied to the variable valve timing mechanism, and a chain case fixed to a cylinder head so as to cover the timing chain and the variable valve timing mechanism, wherein the chain case is formed to bulge in the crankshaft direction and has a bulge portion that covers the variable valve timing mechanism and a cylindrical cylinder portion to which the hydraulic control valve is attached, and the hydraulic control valve has a small diameter portion that is inserted into the cylinder portion from one axial end of the cylinder portion and a large diameter portion that is exposed from the one axial end of the cylinder portion, and the engine is mounted on the vehicle with center lines of a plurality of cylinders inclined with respect to the up-down direction of the vehicle, wherein the cylinder portion is formed adjacent to and below the bulge portion, and the other axial end of the cylinder portion is positioned lower than the one axial end of the cylinder portion, and the chain case has a connecting rib on the other axial end side of the cylinder portion that connects the other axial end of the cylinder portion to the bulge portion. and a reinforcing rib extending in the axial direction of the cylinder portion from one end of the cylinder portion in the axial direction to at least above the large diameter portion along the end of the cylinder portion opposite the bulging portion. It is characterized by: [Effects of the Invention]

[0007] As described above, according to the present invention, it is possible to provide an internal combustion engine in which the portion of the hydraulic control valve exposed to the outside can be protected from foreign objects such as flying stones that fly in from below. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front view of an internal combustion engine according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of a chain case and a hydraulic control valve of an internal combustion engine according to one embodiment of the present invention. [Figure 3] FIG. 3 is a perspective view of a chain case of an internal combustion engine according to one embodiment of the present invention. [Figure 4] FIG. 4 is a front view of a chain case and a hydraulic control valve of an internal combustion engine according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] An internal combustion engine according to one embodiment of the present invention comprises a variable valve timing mechanism around which a timing chain is wound, a hydraulic control valve that controls the hydraulic oil supplied to the variable valve timing mechanism, and a chain case fixed to a cylinder head so as to cover the timing chain and the variable valve timing mechanism, the chain case being formed to bulge in the crankshaft direction and having a bulge portion that covers the variable valve timing mechanism and a cylindrical cylinder portion to which the hydraulic control valve is attached, the hydraulic control valve having a small diameter portion that is inserted into the cylinder portion from one axial end of the cylinder portion and a large diameter portion that is exposed from the one axial end of the cylinder portion, the internal combustion engine being mounted on a vehicle with the center lines of the multiple cylinders inclined relative to the up-down direction of the vehicle, the cylinder portion being formed adjacent to and below the bulge portion, the other axial end of the cylinder portion being positioned lower than the one axial end of the cylinder portion, and the chain case having a connecting rib on the other axial end side of the cylinder portion that connects the other axial end of the cylinder portion to the bulge portion.

[0010] As a result, the internal combustion engine according to one embodiment of the present invention can protect the portion of the hydraulic control valve that is exposed to the outside from foreign objects such as flying stones that fly in from below. [Example]

[0011] An internal combustion engine according to an embodiment of the present invention will now be described with reference to the drawings, in which: Figures 1 to 4 are diagrams showing an internal combustion engine according to an embodiment of the present invention.

[0012] 1 to 4, the up, down, front, back, left, and right directions refer to the up, down, front, back, left, and right directions when the engine is installed in a vehicle. The AB, CD, and EF directions are based on the internal combustion engine removed from the vehicle and held upright with the cylinder head positioned directly above the crankshaft. The AB, CD, and EF directions are perpendicular to each other, and the EF direction coincides with the front-to-rear direction of the vehicle on which the internal combustion engine is installed.

[0013] First, the configuration will be described. In Fig. 1, an internal combustion engine 1 mounted on a vehicle includes a cylinder block 2. The cylinder block 2 is provided with a crankshaft 2A, which extends in the EF direction.

[0014] The cylinder block 2 has three cylinders (not shown) arranged in the EF direction, and the cylinders extend in the AB direction. The internal combustion engine 1 of this embodiment is a front-engine, rear-wheel-drive (FR) type engine mounted vertically. Note that the internal combustion engine 1 is not limited to an in-line engine, and may be, for example, a V-type engine, and the number of cylinders is not limited to three.

[0015] A cylinder head 3 is provided at the end of the cylinder block 2 in the direction A. The cylinder head 3 has an intake port (not shown) for taking in air, an exhaust port 3B for discharging exhaust gas, and intake and exhaust valves (not shown). The exhaust port 3B opens into the side wall of the cylinder head 3 in the direction D. The intake port opens into the side wall of the cylinder head 3 in the direction C.

[0016] A cylinder head cover 4 is installed at the end of the cylinder head 3 in the direction A. An oil pan 5 is installed at the end of the cylinder block 2 in the direction B, and oil for lubricating the internal combustion engine 1 is stored in the oil pan 5.

[0017] The internal combustion engine 1 is installed below the floor panel of the driver's seat at the front of the vehicle (not shown). Therefore, the vehicle equipped with the internal combustion engine 1 is a so-called cab-over vehicle in which the driver's seat is located above the internal combustion engine 1. The internal combustion engine 1 is installed in the vehicle in an attitude in which the center line C of the cylinder is inclined in the left-right direction with respect to the up-down direction of the vehicle.

[0018] An undercover 1A is provided below the internal combustion engine 1. The undercover 1A extends horizontally and covers the internal combustion engine 1 from below. A bottom surface 5A of the oil pan 5 is located at the bottom of the internal combustion engine 1 when mounted on the vehicle. This bottom surface 5A is inclined with respect to the left-right direction of the internal combustion engine 1 itself so as to extend parallel to the undercover 1A when mounted on the vehicle.

[0019] In this way, the internal combustion engine 1 is mounted in a largely inclined position at the front of the vehicle. Therefore, when mounted on the vehicle, the side surface of the internal combustion engine 1 in the direction C (the intake side) faces upward of the vehicle, and the side surface of the internal combustion engine 1 in the direction D (the exhaust side) faces downward of the vehicle.

[0020] The internal combustion engine 1 includes a variable valve timing mechanism 11 around which a timing chain 10 is wound, and a cylinder head cover 4 connected to a cylinder head 3. The internal combustion engine 1 also includes a cylindrical intake hydraulic control valve 15 and an exhaust hydraulic control valve 16 as intake hydraulic control valves that control the hydraulic oil supplied to the variable valve timing mechanism 11.

[0021] The internal combustion engine 1 is equipped with a chain case 20, which is fixed to the side of the cylinder head 3. The chain case 20 covers the timing chain 10 and the variable valve timing mechanism 11. The variable valve timing mechanism 11 has an intake-side variable valve timing mechanism 12 arranged on the intake port side, and an exhaust-side variable valve timing mechanism 13 arranged on the exhaust port 3B side.

[0022] The internal combustion engine 1 is provided with an oil pan 5 which is provided on the opposite side of the chain case from the cylinder head 3 and connected to the cylinder head 3 via the cylinder block 2, an intake port which is provided in the cylinder head 3 to take in air, and an exhaust port 3B which is provided on the opposite side of the chain case from the intake port to discharge exhaust gas.

[0023] The chain case 20 is formed with a bulge 21 that covers the variable valve timing mechanism 11. The bulge 21 bulges in the crankshaft direction. Here, the crankshaft direction refers to the axial direction of the crankshaft 2A. In this embodiment, the bulge 21 bulges outward from the chain case 20 (forward when mounted on the vehicle). The bulge 21 is formed at the end of the chain case 20 on the cylinder head cover 4 side (end in direction A). The intake hydraulic control valve 15 and the exhaust hydraulic control valve 16 are positioned closer to the oil pan 5 than the bulge 21 on the chain case 20.

[0024] The internal combustion engine 1 also includes an oil pump 6, which pumps oil stored in an oil pan 5 to parts requiring lubrication and to a variable valve timing mechanism 11. The oil pump 6 is provided around the crankshaft 2A.

[0025] Here, in this embodiment, the direction of the cylinder head cover 4 and the direction of the oil pan 5 relative to the chain case 20 is the AB direction, the direction of the intake port and the direction of the exhaust port 3B relative to the chain case 20 is the CD direction, and the direction of the outside of the chain case 20 (forward when mounted on the vehicle) and the direction of the inside of the chain case 20 (rear when mounted on the vehicle) is the EF direction.

[0026] The intake oil pressure control valve 15 is disposed on the intake port side in the CD direction, and the exhaust oil pressure control valve 16 is disposed on the exhaust port 3B side in the CD direction.

[0027] 2 and 4, the chain case 20 is formed with a cylindrical intake-side cylinder section 23 to which the intake hydraulic control valve 15 is attached, and a cylindrical exhaust-side cylinder section 24 to which the exhaust hydraulic control valve 16 is attached. The intake-side cylinder section 23 and the exhaust-side cylinder section 24 extend in the CD direction. The exhaust-side cylinder section 24 constitutes the cylinder section and the first cylinder section in the present invention. The intake-side cylinder section 23 constitutes the second cylinder section in the present invention.

[0028] The intake-side cylinder section 23 and the exhaust-side cylinder section 24 are formed adjacent to each other below the bulging section 21. When the internal combustion engine 1 is mounted on a vehicle, the other axial end 23D (end in the direction D; see FIG. 4) of the intake-side cylinder section 23 is located lower than one axial end 23C (end in the direction C; see FIG. 4) of the intake-side cylinder section 23. Similarly, the other axial end 24D (end in the direction D; see FIG. 4) of the exhaust-side cylinder section 24 is located lower than one axial end 24C (end in the direction C; see FIG. 4) of the exhaust-side cylinder section 24.

[0029] 1 and 4, the intake oil pressure control valve 15 has a small diameter portion 15B (see FIG. 1) inserted into the intake side cylinder portion 23 from one axial end 23C (see FIG. 4) of the intake side cylinder portion 23, and a large diameter portion 15A (see FIG. 1) exposed from the axial end 23C (see FIG. 4) of the intake side cylinder portion 23. Similarly, the exhaust oil pressure control valve 16 has a small diameter portion 16B (see FIG. 1) inserted into the exhaust side cylinder portion 24 from one axial end 24C (see FIG. 4) of the exhaust side cylinder portion 24, and a large diameter portion 16A (see FIG. 1) exposed from the axial end 24C (see FIG. 4) of the exhaust side cylinder portion 24.

[0030] 3, an accommodation hole 23A is formed in the intake side cylinder portion 23 to accommodate the small diameter portion 15B of the intake oil pressure control valve 15. An accommodation hole 24A is formed in the exhaust side cylinder portion 24 to accommodate the small diameter portion 16B of the exhaust oil pressure control valve 16.

[0031] 1, an oil pump housing portion 29 that houses the oil pump 6 is formed in the chain case 20. The intake side cylinder portion 23, the exhaust side cylinder portion 24, and the oil pump housing portion 29 are integrally formed.

[0032] The oil pump housing portion 29 is a flat portion that does not bulge in the crankshaft direction of the chain case 20. The oil pump housing portion 29 is disposed below the bulging portion 21 and is continuous with the lower part of the bulging portion 21.

[0033] Because the oil pump housing portion 29 has a flat shape rather than a bulging shape like the bulging portion 21, if left as is, it would have less rigidity than the bulging portion 21. Therefore, in this embodiment, the rigidity of the portions of the oil pump housing portion 29 where the intake side cylinder portion 23 and the exhaust side cylinder portion 24 are provided is improved. Also, because it is preferable to arrange the intake side cylinder portion 23 and the exhaust side cylinder portion 24 compactly in the AB direction, the intake side cylinder portion 23 and the exhaust side cylinder portion 24 are arranged with a shift in the CD direction and the EF direction.

[0034] Connectors (not shown) for electrically controlling the intake hydraulic control valve 15 and the exhaust hydraulic control valve 16 are connected to the intake port sides of the large diameter portions 15A, 16A in the CD direction. The connection ports of each connector face outward (forward) from the chain case 20 in the EF direction.

[0035] Here, because the internal combustion engine 1 of this embodiment is mounted on the vehicle in a significantly tilted position, when mounted on the vehicle, the uppermost parts of the intake hydraulic control valve 15 and the exhaust hydraulic control valve 16 in the vertical direction of the vehicle are located below the uppermost part of the cylinder head cover 4 in the vertical direction of the vehicle. Also, a connector (not shown) at the end of the large diameter portion 16A of the exhaust hydraulic control valve 16 on the intake port side in the CD direction is located below the connector (not shown) at the end of the large diameter portion 15A of the intake hydraulic control valve 15 on the intake port side in the CD direction, in the vertical direction of the vehicle, on the cylinder head cover 4 side.

[0036] As a result, the connector of the large diameter portion 16A of the exhaust hydraulic control valve 16 is located between the connector of the large diameter portion 15A of the intake hydraulic control valve 15 and the cylinder head cover 4, and is located below the uppermost positions in the vehicle vertical direction of both the intake hydraulic control valve 15 and the cylinder head cover 4. Therefore, without locating the exhaust hydraulic control valve 16 inside the cylinder head cover 4, it is possible to prevent foreign matter such as dust from settling and accumulating on the connector of the large diameter portion 16A of the exhaust hydraulic control valve 16.

[0037] The intake hydraulic control valve 15 and the exhaust hydraulic control valve 16 are inserted from the ends of the intake-side cylinder portion 23 and the exhaust-side cylinder portion 24 in direction C (upward when mounted on the vehicle) toward direction D. Therefore, the insertion directions of the intake hydraulic control valve 15 and the exhaust hydraulic control valve 16 are the same, making the insertion work easier.

[0038] Furthermore, when mounted on a vehicle, the intake hydraulic control valve 15 is positioned above the intake side cylinder section 23, and the exhaust hydraulic control valve 16 is positioned above the exhaust side cylinder section 24, so even if foreign matter mixed in the hydraulic oil settles, it is possible to prevent the foreign matter from entering the intake hydraulic control valve 15 and the exhaust hydraulic control valve 16.

[0039] 3, a plurality of cylinder head fastening portions 41, 42 are formed on the edge of the chain case 20, and the cylinder head fastening portions 41, 42 have fastening holes 41A, 42A, respectively, for fastening the oil pump housing portion 29 to the cylinder head 3. The cylinder head fastening portions 41, 42 are adjacent to each other in the direction AB. The portions of the chain case 20 where the cylinder head fastening portions 41, 42 are provided are thick and strong portions.

[0040] 3 and 4, the accommodating hole 23A of the intake-side cylinder portion 23 and the accommodating hole 24A of the exhaust-side cylinder portion 24 are disposed on either the intake port side or the exhaust port 3B side in the CD direction, and open toward either the intake port side or the exhaust port 3B side. In other words, the accommodating hole 23A of the intake-side cylinder portion 23 and the accommodating hole 24A of the exhaust-side cylinder portion 24 are disposed in the same direction in the CD direction and open toward the same direction. In this embodiment, the accommodating hole 23A of the intake-side cylinder portion 23 and the accommodating hole 24A of the exhaust-side cylinder portion 24 are disposed on the intake port side and open toward the intake port side.

[0041] In Figure 3, the axis 23R of the accommodating hole 23A of the intake-side cylinder portion 23 and the axis 24R of the accommodating hole 24A of the exhaust-side cylinder portion 24 are positioned at different positions in the EF direction. Specifically, the axis 23R is positioned more inward of the chain case 20 in the EF direction than the axis 24R. The axes 23R and 24R are parallel. This allows the core pins that form the accommodating holes 23A, 24A to be removed in the same direction, which enables the chain case 20 to be produced using a simple mold structure and further shortens the distance in the CD direction (the direction of the axes 23R, 24R) between the intake-side cylinder portion 23 and the exhaust-side cylinder portion 24.

[0042] In FIG. 1, at least a portion of the intake-side cylinder portion 23 and the exhaust-side cylinder portion 24 overlap in the AB direction.

[0043] In Fig. 3, the chain case 20 has a wall-shaped connecting portion 43. The connecting portion 43 extends in the EF direction and connects the end portion of the intake-side cylinder portion 23 on the exhaust port 3B side in the CD direction (the other end portion 23D shown in Fig. 4) to the end portion of the exhaust-side cylinder portion 24 on the intake port side in the CD direction (the one end portion 24C shown in Fig. 4). The connecting portion 43 also extends in the AB direction. Therefore, the connecting portion 43 connects the intake-side cylinder portion 23 and the exhaust-side cylinder portion 24 in both the EF direction and the AB direction.

[0044] 3, the chain case 20 has a cylindrical oil gallery 27, within which an oil passage (not shown) is formed through which hydraulic oil flows. The oil gallery 27 extends in the CD direction. The chain case 20 has a wall 21A that extends in the EF direction and is continuous with the oil pump housing 29, and this wall 21A is provided at the end of the bulge 21 on the oil pan 5 side in the AB direction. The intake-side cylinder 23 and the exhaust-side cylinder 24 are disposed between the oil gallery 27 and the wall 21A in the AB direction.

[0045] Note that, in order to suppress transmission of vibrations from an intake manifold (not shown) connected to the intake port of the cylinder head 3 to the chain case 20, it is preferable to improve the rigidity of the portion of the chain case 20 near the intake manifold. Therefore, the intake port and the intake manifold connected to the intake port are disposed between the cylinder head fastening portion 41 and the cylinder head fastening portion 42 in the AB direction. This allows the distance between the cylinder head fastening portion 41 and the cylinder head fastening portion 42 to be minimized, thereby improving the rigidity of the portion of the chain case 20 near the cylinder head fastening portions 41, 42. Furthermore, vibrations in the portion of the chain case 20 near the cylinder head fastening portions 41, 42 can be suppressed.

[0046] The chain case 20 has an intake side fastening boss portion 25 and an exhaust side fastening boss portion 26 for attaching the chain case 20 to the cylinder head 3. The intake side fastening boss portion 25 and the exhaust side fastening boss portion 26 are located near the bulge portion 21 in the B direction.

[0047] The B-direction end of the bulge 21 is connected to the A-direction ends of the intake-side cylinder 23 and the exhaust-side cylinder 24. The A-direction end of the intake-side fastening boss 25 is connected to the B-direction end of the intake-side cylinder 23. The A-direction end of the exhaust-side fastening boss 26 is connected to the B-direction end of the exhaust-side cylinder 24. The A-direction end face of the cylinder head 3 forms a flat joint surface extending in the CD and EF directions and is joined to the cylinder head cover 4.

[0048] The intake hydraulic control valve 15, the exhaust hydraulic control valve 16, the intake-side cylinder section 23, and the exhaust-side cylinder section 24 extend in the CD direction. The intake hydraulic control valve 15 and the intake-side cylinder section 23, and the exhaust hydraulic control valve 16 and the exhaust-side cylinder section 24 are arranged side by side in the EF direction.

[0049] The intake side fastening boss portion 25 and the exhaust side fastening boss portion 26 are arranged side by side in the CD direction. The intake side fastening boss portion 25 and the exhaust side fastening boss portion 26 are formed to protrude further in the E direction (forward when mounted on the vehicle) than the intake side cylinder portion 23.

[0050] The intake-side cylinder section 23 and the exhaust-side cylinder section 24 are arranged side by side at different positions in the crankshaft direction. The intake-side cylinder section 23 and the exhaust-side cylinder section 24 are arranged side by side in the crankshaft direction so that they partially overlap in the crankshaft direction. In this embodiment, the exhaust-side cylinder section 24 is arranged adjacent to and in front of the intake-side cylinder section 23.

[0051] Furthermore, when the chain case 20 is viewed along the crankshaft direction (see FIG. 4), the exhaust-side cylinder section 24 is positioned offset toward the exhaust side (direction D) relative to the intake-side cylinder section 23. In this embodiment, the exhaust-side cylinder section 24 is positioned adjacent to the intake-side cylinder section 23 on the direction D side. Therefore, the exhaust-side cylinder section 24 is positioned adjacent to the intake-side cylinder section 23 in both the direction E and the direction D.

[0052] Therefore, the intake side cylinder section 23 is formed adjacent to and above the exhaust side cylinder section 24 so that it is parallel to the axial direction of the exhaust side cylinder section 24 and has a different axial position from the exhaust side cylinder section 24.

[0053] 3 and 4, the oil gallery 27 extends in a direction perpendicular to the crankshaft direction, passing through the end of the intake-side fastening boss 25 in the direction B and the end of the exhaust-side fastening boss 26 in the direction B. The oil gallery 27 is connected to the end of the intake-side fastening boss 25 in the direction B and the end of the exhaust-side fastening boss 26 in the direction B.

[0054] The chain case 20 has a reinforcing rib 28 below the intake side cylinder portion 23. The reinforcing rib 28 extends in the axial direction of the intake side cylinder portion 23. The reinforcing rib 28 connects the intake side cylinder portion 23, the exhaust side cylinder portion 24, and the intake side fastening boss portion 25.

[0055] Specifically, the reinforcing rib 28 extends in the axial direction of the exhaust-side cylinder portion 24 from one axial end 24C of the exhaust-side cylinder portion 24 to at least above the large diameter portion, along the end (end in direction B) of the exhaust-side cylinder portion 24 opposite the bulging portion 21. The reinforcing rib 28 connects the axial end 24C of the exhaust-side cylinder portion 24 to one axial end 23C of the intake-side cylinder portion 23. Specifically, the reinforcing rib 28 extends to the axial end 23C of the intake-side cylinder portion 23, and connects the one end 24C of the exhaust-side cylinder portion 24 to a boss portion 34 formed on the one end 23C of the intake-side cylinder portion 23.

[0056] The chain case 20 has a boss portion 34 at the end of the intake-side cylinder portion 23 on the C and B directions. The boss portion 34 is provided on the B direction side of the bulging portion 21. A leg portion 15C of the intake oil pressure control valve 15 is fastened to the boss portion 34. The leg portion 15C extends in the E and B directions at the end of the large diameter portion 15A of the intake oil pressure control valve 15 on the D direction side.

[0057] The chain case 20 has a boss portion 35 on the A-direction side of the C-direction end of the exhaust-side cylinder portion 24. The boss portion 35 is provided in the bulging portion 21. A leg portion 16C of the exhaust oil pressure control valve 16 is fastened to the boss portion 35. The leg portion 16C extends in the E-direction and the A-direction from the D-direction end of the large diameter portion 16A of the exhaust oil pressure control valve 16.

[0058] An extension rib 31, a connecting rib 32, and an upper rib 33 are formed on the surface of the chain case 20. The extension rib 31, the connecting rib 32, and the upper rib 33 protrude in the E direction.

[0059] A boss portion 37 extending in the E direction is formed near the end portion in the D direction of the bulging portion 21 of the chain case 20. A boss portion 36 extending in the E direction is formed at the end portion in the A direction of the chain case 20.

[0060] The extension rib 31 extends upward from a boss portion 34 formed at one axial end 23C of the intake-side cylinder portion 23. A reinforcing rib 28 is connected to the extension rib 31. The extension rib 31 extends from the boss portion 34 to the vicinity of the cylinder head fastening portion 42 at the end of the chain case 20 in the C direction. The extension rib 31 reinforces the boss portion 34 by dispersing the load acting on the boss portion 34 to the end of the chain case 20 in the C direction.

[0061] The connecting rib 32 is provided on the other end 24D side of the axial direction of the exhaust-side cylinder portion 24 of the chain case 20, near the end portion in the D direction of the bulging portion 21. The connecting rib 32 extends in the A direction and the D direction from the end portion in the D direction of the exhaust-side cylinder portion 24 to the boss portion 37. The connecting rib 32 connects the other end 24D of the axial direction of the exhaust-side cylinder portion 24 to the bulging portion 21. More specifically, the connecting rib 32 connects the other end 24D of the exhaust-side cylinder portion 24 to the boss portion 37 formed on the bulging portion 21.

[0062] Therefore, the exhaust side cylinder portion 24 and the boss portion 37 are connected by the connecting rib 32. As a result, the load acting on the exhaust side cylinder portion 24 is distributed to the chain case 20 via the boss portion 37.

[0063] The upper rib 33 is provided near the end of the chain case 20 in the direction A. The upper rib 33 extends in the directions A and C from the boss portion 35 to the boss portion 36. The upper rib 33 is connected to the boss portion 35 and the boss portion 36. Therefore, the boss portion 35 and the boss portion 36 are connected by the upper rib 33. As a result, the load acting on the boss portion 35 is distributed to the boss portion 36 via the upper rib 33. In addition, a reinforcing rib 38 is connected to the boss portion 35, and the reinforcing rib 38 extends from the boss portion 35 in the direction D. The load acting on the boss portion 35 is also distributed by the reinforcing rib 38 to a portion of the bulge portion 21 near the boss portion 35 in the direction D.

[0064] As described above, in this embodiment, the exhaust-side cylinder portion 24 is formed adjacent to and below the bulge portion 21. Also, the other axial end portion 24D of the exhaust-side cylinder portion 24 is located lower than one axial end portion 24C of the exhaust-side cylinder portion 24. The chain case 20 has a connecting rib 32 on the side of the other axial end portion 24D of the exhaust-side cylinder portion 24 that connects the other axial end portion 24D of the exhaust-side cylinder portion 24 to the bulge portion 21.

[0065] As a result, when a foreign object such as a flying stone flies from the road surface below the vehicle toward the exhaust oil pressure control valve 16 along the arrow A (see FIG. 4), the foreign object collides with the wall portion 21A of the bulging portion 21 or the connecting rib 32, and falls without colliding with the exhaust oil pressure control valve 16. Therefore, the large diameter portion 16A, which is the portion of the exhaust oil pressure control valve 16 exposed to the outside, can be protected from foreign objects such as flying stones flying from below.

[0066] In addition, in this embodiment, the chain case 20 has a reinforcing rib 28 extending in the axial direction of the exhaust side cylinder portion 24 from one axial end 24C of the exhaust side cylinder portion 24 to at least above the large diameter portion, along the end opposite the bulge portion 21 of the exhaust side cylinder portion 24.

[0067] As a result, the large diameter portion 16A of the exhaust oil pressure control valve 16, which is exposed to the outside from the exhaust-side cylinder portion 24, can be surrounded from below by the reinforcing rib 28, the exhaust-side cylinder portion 24, and the bulge portion 21. Therefore, if a foreign object such as a flying stone flies toward the exhaust oil pressure control valve 16 from the road surface below the vehicle along arrow B (see FIG. 4), the foreign object will collide with the bulge portion 21 or the connecting rib 32 and will fall without colliding with the exhaust oil pressure control valve 16. This more effectively protects the large diameter portion 16A of the exhaust oil pressure control valve 16, which is exposed to the outside from the exhaust-side cylinder portion 24, from flying stones and other foreign objects. Note that the intake-side fastening boss portion 25 is connected to the lower surface of the reinforcing rib 28, and the intake-side fastening boss portion 25 has a larger dimension (height) in the E direction than the reinforcing rib 28. Therefore, the intake-side fastening boss portion 25 can also more effectively protect the large diameter portion 16A from flying stones and other foreign objects.

[0068] Furthermore, in this embodiment, the chain case 20 has an intake-side cylinder section 23 formed adjacent to and above the exhaust-side cylinder section 24 so as to be parallel to the axial direction of the exhaust-side cylinder section 24 and at a different axial position from the exhaust-side cylinder section 24. The reinforcing rib 28 connects one axial end 24C of the exhaust-side cylinder section 24 and one axial end 23C of the intake-side cylinder section 23.

[0069] This prevents foreign objects such as flying stones from below the vehicle from colliding with the reinforcing rib 28, effectively protecting the large diameter portion 15A of the intake hydraulic control valve 15 exposed to the outside from the intake side cylinder portion 23.

[0070] Furthermore, by connecting the exhaust side cylinder portion 24 and the intake side cylinder portion 23 with a reinforcing rib 28, the exhaust side cylinder portion 24 and the intake side cylinder portion 23 can be more firmly connected and reinforced, thereby suppressing vibration and deformation of the exhaust side cylinder portion 24 and the intake side cylinder portion 23.

[0071] In this embodiment, the reinforcing rib 28 extends to one axial end 23C of the intake-side cylinder portion 23. The chain case 20 has an extension rib 31 that is connected to the reinforcing rib 28 and extends upward from one axial end 23C of the intake-side cylinder portion 23.

[0072] As a result, the large diameter portion 15A of the intake hydraulic control valve 15 inserted into the intake-side cylinder portion 23 is surrounded from below by the bulge portion 21, the reinforcing rib 28, and the extension rib 31. Therefore, the large diameter portion 15A of the intake hydraulic control valve 15 exposed to the outside from the intake-side cylinder portion 23 can be more effectively protected from foreign objects such as flying stones.

[0073] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0074] 1...internal combustion engine, 3...cylinder head, 11...variable valve timing mechanism, 15...intake hydraulic control valve, 15A...large diameter portion, 15B...small diameter portion, 16...exhaust hydraulic control valve, 16A...large diameter portion, 16B...small diameter portion, 20...chain case, 21...bulge portion, 23...intake side cylinder portion (second cylinder portion), 23A...accommodating hole, 24...exhaust side cylinder portion (cylinder portion, first cylinder portion), 24A...accommodating hole, 24C...one end portion, 24D...other end portion, 28...reinforcing rib, 31...extension rib, 32...connecting rib

Claims

1. A variable valve timing mechanism with a timing chain wrapped around it, a hydraulic control valve for controlling hydraulic oil supplied to the variable valve timing mechanism; a chain case fixed to the cylinder head so as to cover the timing chain and the variable valve timing mechanism, the chain case has a bulging portion formed to bulge in the crankshaft direction and covering the variable valve timing mechanism, and a cylindrical cylinder portion in which the hydraulic control valve is mounted, the hydraulic control valve has a small diameter portion inserted into the cylinder portion from one end in the axial direction of the cylinder portion, and a large diameter portion exposed from the one end in the axial direction of the cylinder portion, An internal combustion engine mounted on a vehicle with centerlines of a plurality of cylinders inclined relative to a vertical direction of the vehicle, the cylinder portion is formed below and adjacent to the bulge portion, The other end of the cylinder portion in the axial direction is disposed lower than the one end of the cylinder portion in the axial direction, The chain case has a connecting rib on the other axial end side of the cylinder portion that connects the other axial end of the cylinder portion to the bulge portion, and a reinforcing rib that extends in the axial direction of the cylinder portion from one axial end of the cylinder portion to at least above the large diameter portion along the end of the cylinder portion opposite the bulge portion.

2. When the cylinder portion is a first cylinder portion, The chain case is a second cylinder portion formed adjacent to and above the first cylinder portion so as to be parallel to the axial direction of the first cylinder portion and to be positioned differently from the first cylinder portion in the axial direction; 2. The internal combustion engine according to claim 1, wherein the reinforcing rib connects one axial end of the first cylinder portion and one axial end of the second cylinder portion.

3. The reinforcing rib extends to one end of the second cylinder portion in the axial direction, 3. The internal combustion engine according to claim 2, wherein the chain case has an extension rib connected to the reinforcing rib and extending upward from one axial end of the second cylinder portion.

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