JPH11107855A - Cylinder head structure of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smooth a flow of oil in an interval between an inlet side cam case and an exhaust side cam case by installing a central side cam case communicating passage, interconnecting both these inlet side and exhaust side cam cases, in the space between an inlet port at the side of an adjacent cylinder on one side and an inlet port at the side of the adjacent cylinder on the other. SOLUTION: One cylinder and two inlet ports 30 (30-1a to 30-3a, 30-1b to 30-3b) are formed in a cylinder head of a 3-cylindered engine in holding one plug hole 28 (28-1 to 28-3) between. An inlet side cam case 32 is formed at one side of the cylinder head like this, and an exhaust side cam case 34 is formed at the other side respectively, and an end side cam case communicating passage 36 (36-1 and 36-2) is installed in both ends of the cylinder head. A blow-by gas passage 42 (42-1 and 42-2) is installed in the cam case on one side, and an oil recovery passage 46 (46-1 and 46-2) in the cam case on the other, respectively. In addition, a central side cam case communicating passage 38 (38-1 and 38-2) is installed in an interval between two adjacent inlet ports 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder head structure of an engine, and more particularly to a cylinder head structure of an engine having a so-called top entry port (TEP) in which an intake port is opened on an upper surface of the cylinder head.

[0002]

2. Description of the Related Art Some vehicle engines are provided with a cylinder head having a so-called top entry port (TEP) having an intake port opened on the upper surface of the cylinder head.

In a cylinder head having a top entry port, when two intake ports are provided for one cylinder, each intake port is located on both sides (in the crankshaft direction) with a plug hole interposed therebetween. The port and the plug hole are all integrally formed by casting.

[0004] That is, as shown in FIGS. 7 to 9, for example, in a cylinder head 102 having a top entry port of a three-cylinder engine, a cylinder (not shown) of a cylinder block arranged in series in the direction of the crank axis X is arranged. A plug hole 106 correspondingly opened on the head upper surface 104
Are provided, and two intake ports 108, 108 per cylinder are opened in the head upper surface 104 in the direction of the crankshaft X with one plug hole 106 interposed therebetween. The intake side cam chamber 110 and the exhaust side cam chamber 112 are formed separately on one side of the cylinder head 102 and the exhaust side cam chamber 112 on the other side of the cylinder head 102. End cam chamber communication passages 114-1 and 114-2 communicating with the side cam chamber 112 are respectively provided, three intake oil recovery passages 116 are provided in the intake cam chamber 110, and one exhaust oil chamber 116 is provided in the exhaust cam chamber 112. Exhaust-side oil recovery passages 118 and two blow-by gas passages 1
20 are provided. In FIG. 9, reference numeral 122 denotes a combustion chamber, and 124 denotes a water jacket.

[0005] Generally, as shown in FIG.
A blow-by gas passage 206 is formed on the intake side, and an oil recovery passage 208 is formed on the exhaust side.

Further, as such a cylinder head structure, for example, Japanese Patent Application Laid-Open No. 2502290,
No. 71311 and Japanese Patent Publication No. 7-54090. Japanese Patent No. 2502290 discloses a cylinder head structure for a DOHC engine, in which a reinforced wall between gallery connecting a pair of oil gallery forming portions, and a rocker arm of each cylinder projecting upward from each oil gallery forming portion. The vertical reinforcing wall connecting the support parts and the horizontal reinforcing wall connecting the two vertical reinforcing walls form a box structure reinforcing body based on the relatively rigid oil gallery forming part, and The passage is formed around the spark plug by connecting the peripheral wall of the plug hole and the bearing. JP-A-7-71311
In the cylinder head structure having a head communication passage communicating with a block communication passage formed in a cylinder block of an engine and a head oil passage for guiding oil to a portion requiring lubrication, the head oil passage is cranked. It is oriented substantially parallel to the axis and located on the head outer wall of the cylinder head, located almost directly above the head communication passage.A blow-by gas passage is provided on one side of the engine, and an oil drop passage is provided on the other side of the engine. It is a thing. In Japanese Patent Publication No. 7-54090, an oil storage chamber is formed in a portion of a cylinder head located above a combustion chamber, and the oil remaining in the oil storage chamber is used to cool the cylinder head and to store the oil. An oil injection nozzle having a front injection port opened toward the bottom wall of the storage chamber is immersed in the room, and lubricating oil is injected from the oil injection port toward the bottom wall of the oil storage chamber. In addition, the injected oil is vigorously delivered to the bottom wall of the oil storage chamber serving as a cooling surface, so that the injected oil directly hits the cooling surface to improve the cooling efficiency.

[0007]

However, conventionally, in a cylinder head having a top entry port, a blow-by gas passage is provided in an intake side cam chamber, and an oil recovery passage is provided in an exhaust side cam chamber. When end-side cam chamber communication paths are provided at both end portions in the longitudinal direction of the cylinder head, oil in the intake-side cam chamber only flows to the exhaust-side cam chamber only from the end-side cam chamber communication path.
Alternatively, since the oil in the exhaust-side cam chamber only flows into the intake-side cam chamber only from the end-side cam chamber communication passage, the oil flow is poor, and the oil easily accumulates in the intake-side cam chamber or the exhaust-side cam chamber. Therefore, there is an inconvenience that the flow of the blow-by gas is not smooth.

In addition, the oil recovery passage and the blow-by gas passage are mixed on one side, and the oil recovery passage and the blow-by gas passage are separately divided into one side and the other side in consideration of the existing base engine. When the cylinder block provided in this way is used in common, the position of the blow-by gas passage and the oil recovery passage must be changed, which is inconvenient.

[0009]

SUMMARY OF THE INVENTION In order to eliminate the above-mentioned disadvantages, the present invention provides a cylinder head on a block deck surface of an engine cylinder block in which a plurality of cylinders are arranged in series. In each of the cylinders, a plug hole is provided on the top surface of the head corresponding to each cylinder, and two intake ports are provided on the top surface of the head with two intake ports per cylinder in the direction of the crank axis with one plug hole interposed therebetween. An intake-side cam chamber and an exhaust-side cam chamber are separately formed on one side of the cylinder head and on the other side of the cylinder head with the plug hole and the intake port as boundaries. Are provided with end-side cam chamber communication passages communicating the intake-side cam chamber and the exhaust-side cam chamber, respectively, and the intake-side cam chamber and the exhaust-side In a cylinder head structure of an engine in which a blow-by gas passage is formed in one of the cam chambers and an oil recovery passage is provided in the other cam chamber, a space between one adjacent plug hole and the other plug hole is provided. A central cam chamber communication passage communicating the intake cam chamber and the exhaust cam chamber is provided between the adjacent intake port on one cylinder side and the intake port on the other cylinder side. .

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides an intake-side cam chamber between an adjacent one-side cylinder-side intake port and the other cylinder-side intake port in addition to the end-side cam chamber communication passages at both end portions of the cylinder head. A central cam chamber communication passage that communicates with the exhaust cam chamber allows oil flow between the intake cam chamber and the exhaust cam chamber even if an intake port is formed as the top entry port. And the flow of the blow-by gas can be smoothly performed.

Further, even if the cylinder block is used in common with the existing base engine, it is not necessary to change the positions of the blow-by gas passage and the oil recovery passage, which is convenient.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; 1 to 5 show an embodiment of the present invention. 3 to 5, reference numeral 2 denotes a three-cylinder engine mounted on a vehicle (not shown), 4 denotes a cylinder block, 6 denotes a cylinder head, and 8 denotes a cylinder head cover. The cylinder block 4 includes three cylinders 1
0 are formed in series in the crankshaft center X direction, and a piston 12 is provided in the cylinder 10 so as to be able to reciprocate. A connecting rod 14 is connected to the piston 12. The cylinder block 4 is provided with a cylinder liner 16, a cylinder barrel 18, and a block-side water jacket 20.

As shown in FIG. 3, the engine 2 has a cylinder head 6 on a block deck surface 4d of the cylinder block 4.
Is mounted and fastened with fixing bolts 26 (not shown) screwed into the head bolt holes 22 and screwed into the block bolt holes 24, and the cylinder axis 10 C is at an angle α with respect to the vertical line V. Mounted on a vehicle at an angle.

The cylinder head 6 is provided with first to third plug holes 28-1 to 28-3 which are opened on the head upper surface 6d corresponding to the cylinders 10, respectively.

The cylinder head 6 is provided with two intake ports 30, 30 per cylinder in the direction of the crankshaft center X with one plug hole 28 interposed therebetween. That is, the cylinder head 6 has a so-called top thin port (TEP) in which the intake port 30 is formed by opening the head upper surface 6d.

That is, the cylinder head 6 has an opening on the head upper surface 6d in the direction of the crankshaft center X, and the first intake ports 30 on both sides of the first plug hole 28-1.
1a and 30-1b are formed, and the second plug hole 28 is formed.
-2, the second intake ports 30-2a, 30-
2b are formed, and third intake ports 30-3a and 30-3b are formed on both sides of the third plug hole 28-3.

Thus, the cylinder head 6 has the intake-side cam chamber 32 on one side and the exhaust-side cam chamber on the other side, with the plug hole 28 and the intake port 30 arranged in the direction of the crankshaft center X as boundaries. 34 are formed separately. This allows
The cylinder head 6 is separated into an intake side and an exhaust side.

The first end side cam chamber communication passage 36- at one end side is connected to the cylinder head 6 at both ends in the longitudinal direction so as to communicate the intake side cam chamber 32 and the exhaust side cam chamber 34.
1 and a second end side cam chamber communication passage 36-2 on the other end side are formed.

Further, adjacent first plug holes 28-1 and second plug holes 28- are connected to the cylinder head 6 so that the intake side cam chamber 32 and the exhaust side cam chamber 34 communicate with each other.
2 between the first intake port 30-1b on the first cylinder 10 (# 1) side and the second intake port 30-2a on the second cylinder 10 (# 2) side. A cam chamber communication passage 38-1 is formed, and a second intake port on the second cylinder 10 (# 2) side is provided between the adjacent second plug hole 28-2 and third plug hole 28-3. 30-1b and the third intake port 30- on the third cylinder 10 (# 3) side.
A second center side cam chamber communication passage 38-2 is formed between 3a. At this time, the first and second central cam chamber communication passages 32-
In order to secure the first and second intake ports 3, the first and second intake ports 3 are provided between the first and second plug holes 28-1 and 28-2.
0-1b, 30-2a in the first and second plug holes 28-
The first and second intake ports 30-2b and 30-3a are provided between the second and third plug holes 28-2 and 28-3. The second plug holes 28-1 and 28-3 are provided close to each other.

The cylinder head 6 has first and second central cam chamber communication passages 38-1 so as to communicate with the intake side cam chamber 32 and the block side blow-by gas passage 40 formed in the cylinder block 4. , 38-2 corresponding to the first,
The first and second blow-by gas passages 42-1 and 42-2 are formed, and the first and second blow-by gas passages are connected to the exhaust-side cam chamber 34 so as to communicate with the block-side oil recovery passage 44 formed in the cylinder block 4. Central cam chamber communication passage 38-
The first and second central head side oil recovery passages 46-1 and 46-2 corresponding to the first and second 38-4 and the end side oil recovery passage 48 corresponding to the second end cam chamber communication passage 36-2. Is formed. The first end side cam chamber communication passage 36-1 corresponds to the chain case oil passage 50.

The intake port 30 is, as shown in FIGS.
Since the center side cam chamber communication passage 38 is formed, it is formed in a non-circular cross section. In order to form the intake port 24 in a non-circular cross-section, first, the intake port 30 is moved toward the center 10C of the cylinder 10 to depress the interference portion with the spark plug guide cylinder 52, In addition, regardless of whether or not the intake port 30 is moved toward the center 10C of the cylinder 10, the intake port 30 at a portion that interferes with the cam chamber communication passage 38 is recessed.

The area of the communication passage 38 of the center cam chamber communication passage 38 is set to be at least half of the area of the oil passage of the center head oil recovery passage 46 so that oil does not accumulate in the intake cam chamber 32 more than necessary. Is set. As a result, the high opening of the head-side blow-by gas passage 42 of the intake-side cam chamber 32 becomes lower than the level of the retained oil,
Oil can be prevented from flowing. In addition, the center side cam chamber communication passage 38 preferably has a certain height so that not only oil but also blow-by gas containing fresh air should flow therethrough. In particular, oil flows only in the lower position. Therefore, the formation of the skirt is preferable.

Further, as shown in FIG. 3, the bottom 54 of the intake and exhaust cam chambers 32, 34, that is, the ceiling portion of the head side water jacket 56 is located on the horizontal line H when the engine 2 is mounted. , Is installed substantially horizontally. In other words, a large vertical member of the upper water jacket of the exhaust port 58 of the cylinder head 6 is used, and the upper surface of the water jacket is inclined upward on the exhaust port 58 side with respect to the mating surface with the cylinder block 4. . This allows the cooling water in the head-side water jacket 56 to flow naturally and freely between the intake side and the exhaust side, and allows the oil from the intake side cam chamber 32 to flow smoothly to the exhaust side cam chamber 34. It is.

The head upper surface 6d of the cylinder head 6
On the intake side, an intake cam shaft 62 is axially provided on an intake side journal receiving surface 60, and on the exhaust side (front), an exhaust cam shaft 66 is axially supported on an exhaust journal receiving surface 64. It is provided. Intake camshaft 62, exhaust camshaft 6
4 opens and closes the intake valve 72 and the exhaust valve 74 via the intake tappet 68 and the exhaust tappet 70. The intake valve 72 and the exhaust valve 74 reciprocate to connect / disconnect the intake port 30 and the exhaust port 58 to / from the combustion chamber 76.

On the head upper surface 6d of the cylinder head 6,
An intake manifold 80 having an intake passage 78 is attached. An ignition plug 82 is attached to the plug hole 28 of the cylinder head 6.

The cylinder head 6 has a head bolt seat 8
An oil flow passage 86 through which oil flows is formed around the head bolt seat 84. Reference numeral 88 denotes a reinforcing rib, 90 denotes a tappet guide boss, 92 denotes a relief cutout for tappet, 94 denotes a relief cutout for bolt, 9
6 is a bolt washer, 98 is a boss for an exhaust bolt, 100
Is an oil supply passage.

Next, the operation of this embodiment will be described.

Crankcase (not shown) of engine 2
Blow-by gas generated in the cylinder head cover 8 rises through the block-side blow-by gas passage 40, the head-side blow-by gas passage 42, and the intake-side cam chamber 32.
Into a breather chamber (not shown). Further, the oil retained in the intake-side cam chamber 32 by lubricating the valve train and the oil retained in the exhaust-side cam chamber 34 both pass through the oil recovery passages 46 and 48 through the block-side oil recovery passage 44 and are discharged into the crankcase. Will be collected.

In this embodiment, the oil retained in the intake side cam chamber 32 is supplied to the first end side cam chamber communication passage 3.
6-1 to the chain case, and to the first central head oil recovery passage 46-1 through the first central cam chamber communication passage 38-1, and further to the second central cam The oil is guided to the second center head oil recovery passage 46-2 through the chamber communication passage 38-2, and further to the end oil recovery passage 48 through the second end cam chamber communication passage 36-2. .

At this time, at least the communication passage area of the central cam chamber communication passage 38 is set to be at least half of the oil passage area of the central head oil passage 46, so that the oil in the intake cam chamber 32 becomes unnecessary. Stagnation can be prevented.

Therefore, also in the cylinder head 6 in which the intake port 30 as the top entry port is formed, the flow of the blow-by gas and the flow of the oil become smooth.

Further, even if the cylinder block 4 is shared in consideration of the existing base engine, it is not necessary to change the positions of the head blow-by gas passage 42 and the oil recovery passage 46, which is convenient.

Further, the oil recovery passages are provided corresponding to the respective communication passages, and the communication passage area of the central cam chamber communication passage is set to at least half of the oil passage area of the central head oil passage. The oil in the intake-side cam chamber 32 and the oil in the exhaust-side cam chamber 34 are guided to the same oil recovery passage, and the area of the communication passage may be set to about half of the area of the oil recovery passage. Can be made smaller, which is advantageous in terms of space.

Further, since the intake port 30 is formed in a non-circular cross section, even in an engine having a small bore pitch between the centers 10C of the adjacent cylinders 10, the intake port 3 can be used.
By changing the shape of 0, the center side cam chamber communication passage 38 can be secured.

Further, the intake and exhaust cam chambers 32, 3
4 is positioned horizontally when the engine is mounted, the oil in the intake side cam chamber 32 flows smoothly to the exhaust side cam chamber 34, and the cooling water in the head side water jacket 56 is cooled by the intake side. It can flow freely freely between the air and the exhaust side.

In this embodiment, as shown in FIG. 6, the bottom 54 of the cam chambers 32, 34 is inclined obliquely downward toward the exhaust side from the horizontal line H to the oblique line 54a at an angle θ. It can also be provided. Thus, the cooling water in the head-side water jacket 56 flows from the exhaust side to the intake side, and the oil in the cam chamber smoothly flows from the intake side to the exhaust side.

It is also possible to set the upper surface portion of the head side water jacket 56 to be lower on the exhaust side.

[0038]

As is apparent from the above detailed description, according to the present invention, one adjacent cylinder-side intake port and the other cylinder-side intake port between one adjacent plug hole and the other plug hole. By providing a central cam chamber communication passage between the intake port and the intake side cam chamber and the exhaust side cam chamber, even if an intake port is formed as the top entry port, the flow of blow-by gas and oil The flow can be smoothly performed.

Further, even if the cylinder block is shared in consideration of the existing base engine, it is not necessary to change the blow-by gas passage and the oil recovery passage, which can be convenient.

[Brief description of the drawings]

FIG. 1 is a plan view of a cylinder head.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 1;

FIG. 4 is a cross-sectional view taken along line IV-IV of FIG.

FIG. 5 is a sectional view of the engine.

FIG. 6 is a sectional view of an engine showing a modification of the embodiment.

FIG. 7 is a plan view of a conventional cylinder head.

FIG. 8 is a cross-sectional view taken along the line II-II of FIG.

FIG. 9 is a cross-sectional view taken along the line 〓〓-〓〓 of FIG. 7;

FIG. 10 is a configuration diagram of a conventional engine.

[Explanation of symbols]

 2 Engine 4 Cylinder block 6 Cylinder head 10 Cylinder 28 Plug hole 30 Intake port 32 Intake side cam chamber 34 Exhaust side cam chamber 36 End side cam chamber communication path 38 Center side cam chamber communication path 46 Center side head oil recovery path 48 End side Head oil recovery passage 54 bottom

Claims (5)

[Claims] 1. A cylinder head is provided on a block deck surface of a cylinder block of an engine in which a plurality of cylinders are arranged in series, and the cylinder head is provided with a plug hole opened on the head upper surface corresponding to each cylinder. In addition, two intake ports per one cylinder are opened in the upper surface of the head in the direction of the crankshaft with one plug hole interposed therebetween, and the intake port is provided on one side of the cylinder head with the plug hole and the intake port as boundaries. An end-side cam chamber and an exhaust-side cam chamber are formed separately on the other side of the cylinder head, and end-side cams communicating with the intake-side cam chamber and the exhaust-side cam chamber at both longitudinal ends of the cylinder head. A chamber communication passage is provided, and a blow-by gas passage is formed in one of the intake-side cam chamber and the exhaust-side cam chamber. In the cylinder head structure of an engine in which an oil recovery passage is provided in the other cam chamber, an intake port on one cylinder side and an intake port on the other cylinder side are provided between one adjacent plug hole and the other plug hole. An engine cylinder head structure, characterized in that a center side cam chamber communication passage communicating between the intake side cam chamber and the exhaust side cam chamber is provided between the ports. 2. An oil recovery passage is provided in the cylinder head so as to correspond to the end cam chamber communication passage and the center cam chamber communication passage, and at least the communication passage area of the center cam chamber communication passage is reduced. 2. The engine cylinder head structure according to claim 1, wherein an area of the oil passage corresponding to the center side cam chamber communication passage is set to at least half of an oil passage area. 3. The intake port is formed in a non-circular cross-section so as to secure the center cam chamber communication passage between one adjacent cylinder and the other cylinder. Item 2. An engine cylinder head structure according to Item 1. 4. The engine cylinder head structure according to claim 1, wherein the bottom of the cam chamber of the cylinder head is disposed substantially horizontally when the engine is mounted. 5. The cylinder head according to claim 1, wherein a bottom portion of the cam chamber of the cylinder head is disposed to be inclined obliquely downward from an intake side to an exhaust side when the engine is mounted. Engine cylinder head structure.