JP7726038B2 - internal combustion engine - Google Patents

Description

The present invention relates to an internal combustion engine.

The solenoid valve unit for an internal combustion engine described in Patent Document 1 includes a first solenoid valve mounted on a cover located at the end of the internal combustion engine and controlling the amount of hydraulic oil supplied from the hydraulic power source to the first hydraulic mechanism; a second solenoid valve mounted on the cover adjacent to the first solenoid valve and controlling the amount of hydraulic oil supplied from the hydraulic power source to the second hydraulic mechanism; and oil filters mounted on the cover between the first and second solenoid valves and connected to each solenoid valve to filter the hydraulic oil supplied to each solenoid valve.

Patent No. 4613760

However, with the technology described in Patent Document 1, when two solenoid valve mounting sections, each housing a solenoid valve, are formed integrally with the chain case, the cast pins that form the bolt holes of the multiple fastening sections of the chain case for fastening to the cylinder head and the cast pins that form the housing holes of the solenoid valve mounting sections that house the solenoid valves must be spaced apart to avoid interference in the casting direction. This reduces the rigidity of the area near the solenoid valve mounting sections located between adjacent fastening sections on the chain case, resulting in the problem that the vibration load caused by the reduced rigidity acts on the solenoid valves.

The present invention was developed in light of the above-mentioned circumstances, and aims to provide an internal combustion engine that can improve the rigidity of the areas near the first and second solenoid valve mounting portions located between adjacent cylinder head fastening portions of the oil pump housing portion of the chain case, and can prevent loads caused by vibrations in the oil pump housing portion from acting on the first and second solenoid valves.

The present invention relates to a variable valve timing mechanism having a timing chain wound therearound, an electromagnetic valve that controls hydraulic oil supplied to the variable valve timing mechanism, a chain case fixed to a cylinder head so as to cover the timing chain and the variable valve timing mechanism, a cylinder head cover connected to the cylinder head, an oil pan provided on the opposite side of the chain case from the cylinder head and connected to the cylinder head via a cylinder block, an intake port provided in the cylinder head for taking in air, and an exhaust port provided on the opposite side of the chain case from the intake port for discharging exhaust gas, an internal combustion engine in which a bulge portion covering a cylinder head cover mechanism is formed on the chain case, and the solenoid valve is arranged on the chain case closer to the oil pan than the bulge portion, wherein when the direction of the cylinder head cover and the direction of the oil pan relative to the chain case are defined as direction AB, the direction of the intake port and the direction of the exhaust port relative to the chain case are defined as direction CD, and the directions of the outside and inside of the chain case relative to the chain case are defined as direction EF, the solenoid valve comprises a first solenoid valve having a large diameter portion and a small diameter portion and arranged on the intake port side in the CD direction, and a second solenoid valve having a large diameter portion and a small diameter portion and arranged on the exhaust port side in the CD direction, the valve case includes an oil pump accommodating portion that accommodates an oil pump, a first electromagnetic valve mounting portion that has an accommodating hole that accommodates at least a small diameter portion of the first electromagnetic valve and is formed integrally with the oil pump accommodating portion, a second electromagnetic valve mounting portion that has an accommodating hole that accommodates at least a small diameter portion of the second electromagnetic valve and is formed integrally with the oil pump accommodating portion, and a plurality of cylinder head fastening portions that have fastening holes for fastening the oil pump accommodating portion to the cylinder head, the accommodating hole of the first electromagnetic valve mounting portion and the accommodating hole of the second electromagnetic valve mounting portion being disposed on one of the intake port side and the exhaust port side in the CD direction and opening toward one of the intake port side and the exhaust port side, The axis of the accommodating hole of the mounting portion and the axis of the accommodating hole of the second solenoid valve mounting portion are arranged at different positions in the EF direction, at least a portion of the first solenoid valve mounting portion and the second solenoid valve mounting portion overlap in the AB direction, the fastening holes of adjacent cylinder head fastening portions are formed outside the projected area when the accommodating hole of the first solenoid valve mounting portion is projected onto the fastening hole side and outside the projected area when the accommodating hole of the second solenoid valve mounting portion is projected onto the fastening hole side, and in the EF direction, the inner end of the accommodating hole of the second solenoid valve mounting portion is arranged outside the chain case more than the outer end of the accommodating hole of the first solenoid valve mounting portion .

As described above, the present invention makes it possible to improve the rigidity of the areas near the first solenoid valve mounting portion and the second solenoid valve mounting portion, which are located between adjacent cylinder head fastening portions of the oil pump housing portion of the chain case, and to provide an internal combustion engine that can prevent loads caused by vibrations in the oil pump housing portion from acting on the first solenoid valve and the second solenoid valve.

FIG. 1 is a front view of an internal combustion engine according to an embodiment of the present invention. FIG. 2 is a side view of an internal combustion engine according to an embodiment of the present invention. FIG. 3 is a perspective view of a chain case for an internal combustion engine according to one embodiment of the present invention. FIG. 4 is a front view of a chain case for an internal combustion engine according to one embodiment of the present invention. FIG. 5 is a side view of a chain case for an internal combustion engine according to one embodiment of the present invention. FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG.

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 solenoid valve that controls hydraulic oil supplied to the variable valve timing mechanism, a chain case fixed to a cylinder head so as to cover the timing chain and the variable valve timing mechanism, a cylinder head cover connected to the cylinder head, an oil pan provided on the opposite side of the chain case from the cylinder head and connected to the cylinder head via a cylinder block, an intake port provided in the cylinder head for taking in air, and an exhaust port provided on the opposite side of the chain case from the intake port for discharging exhaust gas. A bulge portion covering the variable valve timing mechanism is formed on the chain case, and the solenoid valve is disposed on the oil pan side of the bulge portion of the chain case. When the direction of the cylinder head cover and the direction of the oil pan relative to the chain case are defined as AB direction, the direction of the intake port and the exhaust port relative to the chain case are defined as CD direction, and the direction of the outside and inside of the chain case relative to the chain case are defined as EF direction, the solenoid valve has a large diameter portion and a small diameter portion, and is disposed on the intake port side in CD direction. and a second solenoid valve having a large diameter portion and a small diameter portion and disposed on the exhaust port side in the CD direction, the chain case comprising an oil pump accommodating portion that accommodates the oil pump, a first solenoid valve mounting portion having an accommodating hole that accommodates at least the small diameter portion of the first solenoid valve and formed integrally with the oil pump accommodating portion, a second solenoid valve mounting portion having an accommodating hole that accommodates at least the small diameter portion of the second solenoid valve and formed integrally with the oil pump accommodating portion, and a plurality of cylinder head fastening portions having fastening holes for fastening the oil pump accommodating portion to the cylinder head, The mounting portion accommodating hole is located on either the intake port side or the exhaust port side in the CD direction and opens toward either the intake port side or the exhaust port side, the axis of the accommodating hole of the first solenoid valve mounting portion and the axis of the accommodating hole of the second solenoid valve mounting portion are located at different positions in the EF direction, at least a portion of the first solenoid valve mounting portion and the second solenoid valve mounting portion overlap in the AB direction, and the fastening holes of adjacent cylinder head fastening portions are formed outside the projected area of the accommodating hole of the first solenoid valve mounting portion projected onto the fastening hole side, and outside the projected area of the accommodating hole of the second solenoid valve mounting portion projected onto the fastening hole side.

As a result, an internal combustion engine according to one embodiment of the present invention can improve the rigidity of the areas near the first solenoid valve mounting portion and the second solenoid valve mounting portion, which are located between adjacent cylinder head fastening portions of the oil pump housing portion of the chain case, and can suppress the load caused by vibrations in the oil pump housing portion from acting on the first solenoid valve and the second solenoid valve.

An internal combustion engine according to one embodiment of the present invention will now be described with reference to the drawings. Figures 1 to 6 show an internal combustion engine according to one embodiment of the present invention.

In Figures 1 to 6, the AB direction, CD direction, and EF direction are mutually perpendicular directions, and are based on the case where the internal combustion engine has been removed from the vehicle and is held upright with the cylinder head directly above the crankshaft. In this embodiment, the EF direction coincides with the fore-and-aft direction of the vehicle in which the internal combustion engine is mounted.

First, let us explain the configuration. In Figures 1 and 2, an internal combustion engine 1 mounted on a vehicle has a cylinder block 2. A crankshaft 2A is provided in the cylinder block 2, and the crankshaft 2A extends in the EF direction.

The cylinder block 2 has three cylinders (not shown) arranged in the EF direction, with the cylinders extending in the AB direction. The internal combustion engine 1 of this embodiment is a front-engine, rear-wheel-drive (FR) type, longitudinally mounted engine. 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.

A cylinder head 3 is provided above the cylinder block 2. The cylinder head 3 has an intake port 3A (see Figure 2) for taking in air, an exhaust port 3B (see Figure 1) for discharging exhaust gas, and intake and exhaust valves (not shown). The intake port 3A opens into the right wall of the cylinder head 3, and the exhaust port 3B opens into the left wall of the cylinder head 3.

A cylinder head cover 4 is installed above the cylinder head 3. An oil pan 5 is installed below the cylinder block 2, and oil for lubricating the internal combustion engine 1 is stored in the oil pan 5.

The internal combustion engine 1 is installed below the floor panel of the vehicle (not shown). The cylinder block 2 is installed so that the center lines of the multiple cylinders are inclined relative to the vertical direction of the vehicle. More specifically, the cylinder block 2 is installed so that its center line is inclined to the left and right of the vehicle relative to the vertical direction.

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. The bottom surface 5A of the oil pan 5 is located at the bottom of the internal combustion engine 1 when installed in the vehicle. This bottom surface 5A is inclined with respect to the left-right direction of the internal combustion engine 1 itself so that it extends parallel to the undercover 1A when installed in the vehicle.

In this way, the internal combustion engine 1 is mounted at a large inclination in the front of the vehicle. Therefore, when mounted in the vehicle, the right side (intake side) of the internal combustion engine 1 faces upward, and the left side (exhaust side) of the internal combustion engine 1 faces downward.

The internal combustion engine 1 includes a variable valve timing mechanism 11 around which a timing chain 10 is wound, cylindrical first and second solenoid valves 15 and 16 serving as hydraulic control valves that control the hydraulic oil supplied to the variable valve timing mechanism 11, and a cylinder head cover 4 connected to the cylinder head 3. The internal combustion engine 1 also includes a chain case 20 fixed to the cylinder head 3 so as to cover the timing chain 10 and variable valve timing mechanism 11. The variable valve timing mechanism 11 includes an intake-side variable valve timing mechanism 12 arranged on the intake port 3A side and an exhaust-side variable valve timing mechanism 13 arranged on the exhaust port 3B side.

The internal combustion engine 1 is provided with an oil pan that is located on the opposite side of the chain case from the cylinder head 3 and is connected to the cylinder head 3 via the cylinder block 2, an intake port 3A that is located in the cylinder head 3 and takes in air, and an exhaust port 3B that is located on the opposite side of the chain case from the intake port 3A and discharges exhaust gases.

The chain case 20 has a bulge 21 that covers the variable valve timing mechanism 11. The bulge 21 bulges outward (forward) from the chain case 20. The bulge 21 is formed at the end (upper end) of the chain case 20 on the cylinder head cover 4 side. The first solenoid valve 15 and the second solenoid valve 16 are positioned closer to the oil pan 5 than the bulge 21 on the chain case 20.

The internal combustion engine 1 also has an oil pump 6 around the crankshaft 2A that pumps oil stored in the oil pan 5 to areas requiring lubrication and the variable valve timing mechanism 11.

In this embodiment, the direction of the cylinder head cover and the direction of the oil pan relative to the chain case 20 is the AB direction, the direction of the intake port 3A and the direction of the exhaust port 3B relative to the chain case 20 is the CD direction, and the direction of the outside and inside of the chain case 20 is the EF direction.

The first solenoid valve 15 is located on the intake port 3A side in the CD direction. The first solenoid valve 15 has a large diameter portion 15A and a small diameter portion 15B. The second solenoid valve 16 is located on the exhaust port 3B side in the CD direction. The second solenoid valve 16 has a large diameter portion 16A and a small diameter portion 16B. Connectors (not shown) for electrically controlling the first solenoid valve 15 and the second solenoid valve 16 are connected to the intake port 3A side in the CD direction of the large diameter portions 15A and 16A. The connection ports of each connector face outward (forward) from the chain case 20 in the EF direction.

Here, because the internal combustion engine 1 of this embodiment is mounted on the vehicle in a significantly tilted position, the tops of the first solenoid valve 15 and the second solenoid valve 16 in the vehicle's up-down direction are positioned lower than the top of the cylinder head cover 4 in the vehicle's up-down direction. Furthermore, the connector (not shown) at the end of the second solenoid valve 16 on the intake port 3A side in the CD direction is positioned lower in the vehicle's up-down direction than the connector (not shown) at the end of the first solenoid valve 15 on the intake port 3A side in the CD direction, on the cylinder head cover 4 side.

As a result, the connector of the second solenoid valve 16 is positioned between the connector of the first solenoid valve 15 and the cylinder head cover 4, and below the top of both the first solenoid valve 15 and the cylinder head cover 4 in the vertical direction of the vehicle. This prevents dust from collecting in the connector of the second solenoid valve 16 without having to position the second solenoid valve 16 inside the cylinder head cover 4.

The chain case 20 has an oil pump housing portion 29 that houses the oil pump 6, a first solenoid valve mounting portion 23 that has a housing hole 23A (see Figure 3) that houses at least the small diameter portion 15B of the first solenoid valve 15, and a second solenoid valve mounting portion 24 that has a housing hole 24A (see Figure 3) that houses at least the small diameter portion 16B of the second solenoid valve 16. The first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24 are formed integrally with the oil pump housing portion 29.

Here, the oil pump housing portion 29 is a flat portion of the chain case 20 that does not bulge in the direction of the crankshaft 2A. The oil pump housing portion 29 is located below the bulging portion 21 and is continuous with the lower portion of the bulging portion 21. Because the oil pump housing portion 29 has a flat shape rather than a bulging shape like the bulging portion 21, it would have lower rigidity than the bulging portion 21 if left as is. Therefore, in this embodiment, the rigidity of the portions of the oil pump housing portion 29 where the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24 are provided is improved. Furthermore, because it is preferable to arrange the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24 compactly in the AB direction, the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24 are arranged with a shift in the CD direction and the EF direction.

The chain case 20 has multiple cylinder head fastening portions 41, 42, each of which has a fastening hole 41A, 42A for fastening the oil pump housing 29 to the cylinder head 3. The cylinder head fastening portions 41, 42 are adjacent to each other in the AB direction.

In Figures 3 and 4, the accommodating hole 23A of the first solenoid valve mounting portion 23 and the accommodating hole 24A of the second solenoid valve mounting portion 24 are positioned on either the intake port 3A side or the exhaust port 3B side in the CD direction, and open toward either the intake port 3A side or the exhaust port 3B side. In other words, the accommodating hole 23A of the first solenoid valve mounting portion 23 and the accommodating hole 24A of the second solenoid valve mounting portion 24 are positioned in the same direction in the CD direction and open toward the same direction. In this embodiment, the accommodating hole 23A of the first solenoid valve mounting portion 23 and the accommodating hole 24A of the second solenoid valve mounting portion 24 are positioned on the intake port 3A side and open toward the intake port 3A side.

In Figures 3 and 5, the axis 23R of the accommodating hole 23A of the first solenoid valve mounting portion 23 and the axis 24R of the accommodating hole 24A of the second solenoid valve mounting 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 may be parallel, in which case the core pins that form the accommodating holes 23A and 24A can be removed in the same direction. This allows 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 and 24R) between the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24.

In FIG. 5, at least a portion of the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24 overlap in the direction AB. Specifically, in the direction AB, the lower end portion 24L of the second solenoid valve mounting portion 24 is disposed between the upper end portion 23U and the lower end portion 23L of the first solenoid valve mounting portion 23, and the upper end portion 23U of the first solenoid valve mounting portion 23 is disposed between the upper end portion 24U and the lower end portion 24L of the second solenoid valve mounting portion 24.

In FIG. 4 , the fastening holes 41A, 42A of adjacent cylinder head fastening portions 41, 42 are formed outside the projected area of the accommodating hole 23A of the first solenoid valve mounting portion 23 projected onto the fastening holes 41A, 42A, and outside the projected area of the accommodating hole 24A of the second solenoid valve mounting portion 24 projected onto the fastening holes 41A, 42A. Specifically, the fastening holes 41A, 42A of the cylinder head fastening portions 41, 42 are formed outside the area between the upper end 23A1 and the lower end 23A2 of the projected area of the accommodating hole 23A of the first solenoid valve mounting portion 23 projected onto the fastening holes 41A, 42A. Furthermore, the fastening holes 41A, 42A of the cylinder head fastening portions 41, 42 are formed outside the area between the upper end 24A1 and the lower end 24A2 of the projected area of the accommodating hole 24A of the second solenoid valve mounting portion 24 projected onto the fastening holes 41A, 42A. In this embodiment, as shown in FIG. 4, the cylinder head fastening portion 41 is positioned above the upper end 24A1 of the projection area of the accommodating hole 24A of the second solenoid valve mounting portion 24, and the cylinder head fastening portion 42 is positioned below the lower end 23A2 of the projection area of the accommodating hole 23A of the first solenoid valve mounting portion 23.

As shown in Figure 5, in the EF direction, the inner end 24F of the chain case 20 of the accommodating hole 24A of the second solenoid valve mounting portion 24 is positioned further outside the chain case 20 (to the right in Figure 5) than the outer end 23E of the chain case 20 of the accommodating hole 23A of the first solenoid valve mounting portion 23.

As shown in FIG. 4, in the CD direction, the end 24C of the accommodation hole 24A of the second solenoid valve mounting portion 24 on the intake port 3A side is positioned closer to the exhaust port 3B than the end 23D of the accommodation hole 23A of the first solenoid valve mounting portion 23 on the exhaust port 3B side.

In Figures 3 and 6, the chain case 20 has a connecting portion 43. The connecting portion 43 extends in the EF direction and connects the end of the first solenoid valve mounting portion 23 on the exhaust port 3B side in the CD direction to the end of the second solenoid valve mounting portion 24 on the intake port 3A side in the CD direction. The connecting portion 43 also extends in the AB direction. Therefore, the connecting portion 43 connects the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24 in both the EF direction and the AB direction.

In Figure 6, the chain case 20 has an oil gallery portion 27 that extends in the CD direction and through which oil flows through an internal oil passage 27A, and a wall portion 21A that is provided at the end of the bulge portion 21 on the oil pan 5 side in the AB direction (the lower end in Figure 6), extends in the EF direction, and is continuous with the oil pump housing portion 29. The first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24 are located between the oil gallery portion 27 and the wall portion 21A in the AB direction.

In order to prevent vibrations from the intake manifold (not shown) connected to the intake port 3A of the cylinder head 3 from being transmitted to the chain case 20, it is preferable to improve the rigidity of the chain case 20 near the intake manifold. Therefore, as shown in FIG. 3, the intake port 3A and the intake manifold connected to this intake port 3A are located between the cylinder head fastening portion 41 and the cylinder head fastening portion 42 in the AB direction. Furthermore, the projected area of the accommodating hole 23A of the first solenoid valve mounting portion 23 projected toward the fastening holes 41A and 42A and the projected area of the accommodating hole 24A of the second solenoid valve mounting portion 24 projected toward the fastening holes 41A and 42A are both located between the cylinder head fastening portion 41 and the cylinder head fastening portion 42 in the AB direction. This minimizes the distance between the cylinder head fastening portion 41 and the cylinder head fastening portion 42, thereby improving the rigidity of the chain case 20 near the cylinder head fastening portions 41 and 42. It also suppresses vibrations in the areas of the chain case 20 near the cylinder head fastening portions 41, 42.

As described above, in this embodiment, the internal combustion engine 1 is equipped with a first solenoid valve 15 having a large diameter portion 15A and a small diameter portion 15B and positioned on the intake port 3A side in the CD direction, and a second solenoid valve 16 having a large diameter portion 16A and a small diameter portion 16B and positioned on the exhaust port 3B side in the CD direction.

The chain case 20 also includes an oil pump housing 29 that houses the oil pump 6, a first solenoid valve mounting portion 23 that has a housing hole 23A that houses at least the small diameter portion 15B of the first solenoid valve 15 and is formed integrally with the oil pump housing 29, a second solenoid valve mounting portion 24 that has a housing hole 24A that houses at least the small diameter portion 16B of the second solenoid valve 16 and is formed integrally with the oil pump housing 29, and multiple cylinder head fastening portions 41, 42 that have fastening holes 41A, 42A for fastening the oil pump housing 29 to the cylinder head 3.

Furthermore, the accommodation hole 23A of the first solenoid valve mounting portion 23 and the accommodation hole 24A of the second solenoid valve mounting portion 24 are positioned on either the intake port 3A side or the exhaust port 3B side in the CD direction, and open toward either the intake port 3A side or the exhaust port 3B side.

Furthermore, the axis 23R of the accommodating hole 23A of the first solenoid valve mounting portion 23 and the axis 24R of the accommodating hole 24A of the second solenoid valve mounting portion 24 are positioned at different positions in the EF direction. At least a portion of the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24 overlap in the AB direction. The fastening holes 41A and 42A of adjacent cylinder head fastening portions 41 and 42 are formed outside the projection area of the accommodating hole 23A of the first solenoid valve mounting portion 23 projected onto the fastening holes 41A and 42A, and outside the projection area of the accommodating hole 24A of the second solenoid valve mounting portion 24 projected onto the fastening holes 41A and 42A.

This allows the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24 to be positioned compactly in the A-B direction, preventing interference between the core pins used to form the fastening holes 41A, 42A of the cylinder head fastening portions 41, 42 of the oil pump housing portion 29 and the core pins used to form the housing holes 23A, 24A of the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24 during the casting process when the chain case 20 is produced by casting. Furthermore, the distance between the cylinder head fastening portions 41, 42 can be reduced.

This improves the rigidity of the oil pump housing 29 in the areas near the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24, between the cylinder head fastening portions 41, 42. This reduces the load caused by vibrations from the oil pump housing 29 to the first solenoid valve 15 and the second solenoid valve 16.

As a result, the rigidity of the areas near the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24, which are located between the adjacent cylinder head fastening portions 41, 42 of the oil pump housing portion 29 of the chain case 20, can be improved, and the load caused by vibration of the oil pump housing portion 29 can be prevented from acting on the first solenoid valve 15 and the second solenoid valve 16.

In addition, in this embodiment, in the EF direction, the inner end 24F of the accommodating hole 24A of the second solenoid valve mounting portion 24 is positioned further outward from the chain case 20 than the outer end 23E of the accommodating hole 23A of the first solenoid valve mounting portion 23. In addition, in the CD direction, the end 24C of the accommodating hole 24A of the second solenoid valve mounting portion 24 on the intake port 3A side is positioned closer to the exhaust port 3B than the end 23D of the accommodating hole 23A of the first solenoid valve mounting portion 23 on the exhaust port 3B side.

This reduces the distance in the AB direction between the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24, and allows the accommodating hole 23A of the first solenoid valve mounting portion 23 and the accommodating hole 24A of the second solenoid valve mounting portion 24 to be spaced apart in the CD and EF directions. This prevents casting defects such as blowholes from occurring between the outer periphery of the first solenoid valve mounting portion 23 and the outer periphery of the second solenoid valve mounting portion 24.

This eliminates any adverse effects on the precise control of the variable valve timing mechanism and reduces the distance between the first solenoid valve 15 and the second solenoid valve 16 in the A-B direction.

As a result, the rigidity of the area of the oil pump housing 29 between the cylinder head fastening portions 41, 42 and near the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24 can be further improved, and the load due to vibration from the oil pump housing 29 to the first solenoid valve 15 and the second solenoid valve 16 can be further reduced.

In addition, in this embodiment, the chain case 20 has a connecting portion 43 that connects the end of the first solenoid valve mounting portion 23 on the exhaust port 3B side in the CD direction to the end of the second solenoid valve mounting portion 24 on the intake port 3A side in the CD direction, and the connecting portion 43 extends in the EF direction.

As a result, the connecting portion 43 connects the end of the first solenoid valve mounting portion 23 on the exhaust port 3B side to the end of the second solenoid valve mounting portion 24 on the intake port 3A side, so that vibrations, particularly in the A and B directions, between the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24 can be damped by the connecting portion 43. This prevents vibrations from one of the first solenoid valve 15 and the second solenoid valve 16 from affecting the other, particularly in the A and B directions. This protects the first solenoid valve 15 and the second solenoid valve 16 from the adverse effects of vibration transmission.

In this embodiment, the chain case 20 has an oil gallery portion 27 that extends in the CD direction and through which oil flows, and a wall portion 21A that is provided at the end of the bulge portion 21 on the oil pan 5 side in the AB direction, extends in the EF direction, and is continuous with the oil pump housing portion 29. The first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24 are positioned between the oil gallery portion 27 and the wall portion 21A in the AB direction.

This minimizes the distance between the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24, and also minimizes the distance in the A-B direction between the variable valve timing mechanism 11 and the oil gallery portion 27. This improves the responsiveness and control accuracy of the variable valve timing mechanism 11. Furthermore, because the length of the oil path from the oil gallery portion 27 to the variable valve timing mechanism 11 can be minimized, the amount of oil required to circulate between the first solenoid valve mounting portion 23 and the second solenoid valve mounting portion 24 can be reduced, resulting in weight reductions for the internal combustion engine 1 and the vehicle.

While embodiments of the present invention have been disclosed, it will be apparent to those skilled in the art that modifications may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be encompassed by the following claims.

1...Internal combustion engine, 2...Cylinder block, 3...Cylinder head, 3A...Intake port, 3B...Exhaust port, 4...Cylinder head cover, 5...Oil pan, 10...Timing chain, 11...Variable valve timing mechanism, 15...First solenoid valve, 15A...Large diameter portion, 15B...Small diameter portion, 16...Second solenoid valve, 16A...Large diameter portion, 16B...Small diameter portion, 20...Chain case, 21...Bulge portion, 21A...Wall portion, 23...First solenoid valve mounting portion, 23A...Accommodating hole, 23R...Axis, 24...Second solenoid valve mounting portion, 24A...Accommodating hole, 24R...Axis, 27...Oil gallery portion, 29...Oil pump housing portion, 41, 42...Cylinder head fastening portion, 41A, 42A...Fastening hole, 43...Connecting portion

Claims (4)

A variable valve timing mechanism with a timing chain wrapped around it,
an electromagnetic valve for controlling hydraulic oil supplied to the variable valve timing mechanism;
a chain case fixed to a cylinder head so as to cover the timing chain and the variable valve timing mechanism;
a cylinder head cover connected to the cylinder head;
an oil pan provided on the opposite side of the chain case from the cylinder head and connected to the cylinder head via a cylinder block;
an intake port provided in the cylinder head for taking in air;
an exhaust port that is provided on the opposite side of the chain case from the intake port and that discharges exhaust gas,
a bulge portion covering the variable valve timing mechanism is formed on the chain case;
an internal combustion engine in which the solenoid valve is disposed closer to the oil pan than the bulging portion of the chain case,
a direction of the cylinder head cover and a direction of the oil pan relative to the chain case are defined as an AB direction;
a direction of the intake port and a direction of the exhaust port relative to the chain case is defined as a CD direction;
When the outward and inward directions of the chain case relative to the chain case are defined as EF directions,
the solenoid valve includes a first solenoid valve having a large diameter portion and a small diameter portion and disposed on the intake port side in the CD direction, and a second solenoid valve having a large diameter portion and a small diameter portion and disposed on the exhaust port side in the CD direction,
The chain case is
an oil pump housing portion that houses an oil pump;
a first solenoid valve mounting portion that has an accommodating hole that accommodates at least a small diameter portion of the first solenoid valve and is formed integrally with the oil pump accommodating portion;
a second electromagnetic valve mounting portion that has an accommodation hole that accommodates at least a small diameter portion of the second electromagnetic valve and is formed integrally with the oil pump accommodation portion;
a plurality of cylinder head fastening portions having fastening holes for fastening the oil pump housing portion to the cylinder head,
an accommodation hole of the first solenoid valve attachment portion and an accommodation hole of the second solenoid valve attachment portion are arranged on one of the intake port side and the exhaust port side in the CD direction, and are open toward one of the intake port side and the exhaust port side,
an axis of the accommodation hole of the first solenoid valve attachment portion and an axis of the accommodation hole of the second solenoid valve attachment portion are disposed at different positions in the EF direction,
At least a portion of the first solenoid valve mounting portion and the second solenoid valve mounting portion overlap in the AB direction,
the fastening holes of the adjacent cylinder head fastening portions are formed outside a projected area when the accommodating hole of the first solenoid valve mounting portion is projected onto the fastening hole side, and outside a projected area when the accommodating hole of the second solenoid valve mounting portion is projected onto the fastening hole side ,
an internal combustion engine characterized in that, in the EF direction, an inner end of the chain case of the accommodation hole of the second solenoid valve mounting portion is positioned further outside of the chain case than an outer end of the chain case of the accommodation hole of the first solenoid valve mounting portion . A variable valve timing mechanism with a timing chain wrapped around it,
an electromagnetic valve for controlling hydraulic oil supplied to the variable valve timing mechanism;
a chain case fixed to a cylinder head so as to cover the timing chain and the variable valve timing mechanism;
a cylinder head cover connected to the cylinder head;
an oil pan provided on the opposite side of the chain case from the cylinder head and connected to the cylinder head via a cylinder block;
an intake port provided in the cylinder head for taking in air;
an exhaust port that is provided on the opposite side of the chain case from the intake port and that discharges exhaust gas,
a bulge portion covering the variable valve timing mechanism is formed on the chain case;
an internal combustion engine in which the solenoid valve is disposed closer to the oil pan than the bulging portion of the chain case,
a direction of the cylinder head cover and a direction of the oil pan relative to the chain case are defined as an AB direction;
a direction of the intake port and a direction of the exhaust port relative to the chain case is defined as a CD direction;
When the outward and inward directions of the chain case relative to the chain case are defined as EF directions,
the solenoid valve includes a first solenoid valve having a large diameter portion and a small diameter portion and disposed on the intake port side in the CD direction, and a second solenoid valve having a large diameter portion and a small diameter portion and disposed on the exhaust port side in the CD direction,
The chain case is
an oil pump housing portion that houses an oil pump;
a first solenoid valve mounting portion that has an accommodating hole that accommodates at least a small diameter portion of the first solenoid valve and is formed integrally with the oil pump accommodating portion;
a second electromagnetic valve mounting portion that has an accommodation hole that accommodates at least a small diameter portion of the second electromagnetic valve and is formed integrally with the oil pump accommodation portion;
a plurality of cylinder head fastening portions having fastening holes for fastening the oil pump housing portion to the cylinder head,
an accommodation hole of the first solenoid valve attachment portion and an accommodation hole of the second solenoid valve attachment portion are arranged on one of the intake port side and the exhaust port side in the CD direction, and are open toward one of the intake port side and the exhaust port side,
an axis of the accommodation hole of the first solenoid valve attachment portion and an axis of the accommodation hole of the second solenoid valve attachment portion are disposed at different positions in the EF direction,
At least a portion of the first solenoid valve mounting portion and the second solenoid valve mounting portion overlap in the AB direction,
the fastening holes of the adjacent cylinder head fastening portions are formed outside a projected area when the accommodating hole of the first solenoid valve mounting portion is projected onto the fastening hole side, and outside a projected area when the accommodating hole of the second solenoid valve mounting portion is projected onto the fastening hole side,
an end portion of the accommodation hole of the second solenoid valve mounting portion on the intake port side in the CD direction is disposed closer to the exhaust port side than an end portion of the accommodation hole of the first solenoid valve mounting portion on the exhaust port side. A variable valve timing mechanism with a timing chain wrapped around it,
an electromagnetic valve for controlling hydraulic oil supplied to the variable valve timing mechanism;
a chain case fixed to a cylinder head so as to cover the timing chain and the variable valve timing mechanism;
a cylinder head cover connected to the cylinder head;
an oil pan provided on the opposite side of the chain case from the cylinder head and connected to the cylinder head via a cylinder block;
an intake port provided in the cylinder head for taking in air;
an exhaust port that is provided on the opposite side of the chain case from the intake port and that discharges exhaust gas,
a bulge portion covering the variable valve timing mechanism is formed on the chain case;
an internal combustion engine in which the solenoid valve is disposed closer to the oil pan than the bulging portion of the chain case,
a direction of the cylinder head cover and a direction of the oil pan relative to the chain case are defined as an AB direction;
a direction of the intake port and a direction of the exhaust port relative to the chain case is defined as a CD direction;
When the outward and inward directions of the chain case relative to the chain case are defined as EF directions,
the solenoid valve includes a first solenoid valve having a large diameter portion and a small diameter portion and disposed on the intake port side in the CD direction, and a second solenoid valve having a large diameter portion and a small diameter portion and disposed on the exhaust port side in the CD direction,
The chain case is
an oil pump housing portion that houses an oil pump;
a first solenoid valve mounting portion that has an accommodating hole that accommodates at least a small diameter portion of the first solenoid valve and is formed integrally with the oil pump accommodating portion;
a second electromagnetic valve mounting portion that has an accommodation hole that accommodates at least a small diameter portion of the second electromagnetic valve and is formed integrally with the oil pump accommodation portion;
a plurality of cylinder head fastening portions having fastening holes for fastening the oil pump housing portion to the cylinder head,
an accommodation hole of the first solenoid valve attachment portion and an accommodation hole of the second solenoid valve attachment portion are arranged on one of the intake port side and the exhaust port side in the CD direction, and are open toward one of the intake port side and the exhaust port side,
an axis of the accommodation hole of the first solenoid valve attachment portion and an axis of the accommodation hole of the second solenoid valve attachment portion are disposed at different positions in the EF direction,
At least a portion of the first solenoid valve mounting portion and the second solenoid valve mounting portion overlap in the AB direction,
the fastening holes of the adjacent cylinder head fastening portions are formed outside a projected area when the accommodating hole of the first solenoid valve mounting portion is projected onto the fastening hole side, and outside a projected area when the accommodating hole of the second solenoid valve mounting portion is projected onto the fastening hole side,
The chain case is
a connecting portion that connects an end portion of the first solenoid valve mounting portion on the exhaust port side in the CD direction and an end portion of the second solenoid valve mounting portion on the intake port side in the CD direction,
The internal combustion engine, wherein the connecting portion extends in the EF direction. The chain case is
an oil gallery portion extending in the CD direction and through which oil flows;
a wall portion provided at an end of the bulging portion on the oil pan side in the AB direction, extending in the EF direction and continuing to the oil pump accommodating portion,
4. The internal combustion engine according to claim 1, wherein the first solenoid valve mounting portion and the second solenoid valve mounting portion are disposed between the oil gallery portion and the wall portion in the direction AB.