JP3048401B2 - Engine cylinder block structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a cylinder block of an engine.

[0002]

2. Description of the Related Art Conventionally, blow-by gas generated inside an engine during operation of the engine is collected and introduced into an intake system to be processed without being released to the atmosphere. In this case, the blow-by gas contains oil mist. However, since it is not preferable that the oil mist is brought into the intake system, the blow-by gas is usually removed in advance by providing an oil separator. It is known that the oil separator is arranged above the engine while avoiding interference with other devices and the like. Japanese Utility Model Publication No. 2-29214 discloses a structure provided above a camshaft in a cylinder head cover above an engine.

[0003]

The conventional structure as described above has a problem that the upper part of the engine becomes large and the layout restriction increases. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems and provide a cylinder block structure having an oil separator having an excellent oil separating effect and having a compact engine configuration.

[0004]

In order to solve the above problem, the present invention has the following arrangement. That is, in the cylinder block of the present invention, a space formed around the cylinder bore in which the piston slides is divided vertically.
The upper space constitutes a water jacket through which engine cooling water flows, the lower space constitutes a blow-by gas passage through which blow-by gas flows, and a head bolt provided near a partition wall that partitions between the cylinder bores is inserted. A rib protruding into the blow-by gas passage below the bolt hole.

In the structure of the present invention, the blow-by gas passage formed in the cylinder block has a communicating portion communicating with the blow-by gas passage provided in the cylinder head, and the bolt hole of the head bolt is connected to the communicating hole. It is characterized by being provided inside the unit.

More preferably, the blow-by gas passage formed in the cylinder block has a communicating portion communicating with the blow-by gas passage provided in the cylinder head, and a bolt hole of the head bolt is provided in the communicating portion. . Further, a communication portion may be provided for communicating the blow-by gas passage with a crank chamber provided below the cylinder block. Further, in a preferred embodiment, a blow-by gas outlet is provided at an end of the cylinder block in the cylinder arrangement direction.

[0007]

In the structure of the conventional cylinder block, the space around the cylinder bore around the cylinder bore of the cylinder block in which the piston slides is used as a water jacket up to a position extending to the lower portion of the cylinder bore. However, according to the study of the present inventors, what is actually thermally severe is the upper portion of the cylinder bore, and the lower portion of the cylinder bore is practically less necessary. Therefore, in a conventional structure in which the periphery of the cylinder bore is entirely cooled up and down, during a specific operation such as a cold operation, overcooling may occur, which may adversely affect the engine output performance. Based on such knowledge, in the present invention, the space around the cylinder bore is vertically divided, the water jacket is formed only in the upper space, and the lower space is formed as a blow-by gas passage. To solve the conventional layout problem.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. Referring to FIG. 1, an engine 1 to which the present invention is applied is a V-type six-cylinder engine, which includes a cylinder block 2 having two banks each intersecting in a V-shape and having three cylinders. Under the cylinder block 2, a common crank chamber 3 is formed for each bank. A cylinder bore 4 extending from the crank chamber 3 to the inside of each bank is formed.
A piston 5 is slidably disposed. The piston 5 is connected to a crankshaft (not shown) extending in the cylinder arrangement direction into the crank chamber 3 via a connecting rod 6. A cylinder head 7 is combined with an upper part of the cylinder block 2, and a recess formed in an upper part of the cylinder bore 4 and a lower part of the cylinder head 7 forms a combustion chamber 8. In the combustion chamber 8,
The tip of the spark plug 9 protrudes. A valve operating mechanism 10 is disposed in a space above the cylinder head 7, and the valve operating mechanism 10 includes a camshaft 1 on which a cam 11 is formed.
2. Rocker shaft 1 supporting rocker arm 13
4. The valve device 15 is driven. The upper space of the cylinder head 7 is covered by a cylinder head cover 16. An intake passage 17 and an exhaust passage 18 are connected to the cylinder head 7, respectively.

A space extending in the direction of the cylinder bore 4 is provided around the cylinder bore 4 of the cylinder block 2, and this space is vertically divided by a middle deck 19. The upper space constitutes a water jacket 20 through which engine cooling water flows, and the lower space constitutes a combustion chamber 8.
And a blow-by gas passage 21 through which blow-by gas mainly composed of gas leaking into the crank chamber 3 from between the piston ring and the cylinder wall is formed. Blow-by gas passage 2 formed in this cylinder block 2
The lower end of 1 is divided by a lower deck 22 constituting the lower end of the cylinder bore 4. Referring to FIG. 2 and FIG. 3 together, a lower portion of the blow-by gas passage 21 communicates with the crank chamber 3 through a communication passage 23.
In the blow-by gas passage 21, ribs 24 project in a direction orthogonal to the longitudinal direction, that is, in a lateral direction at a position where the inter-cylinder region is substantially divided into two in the cylinder arrangement direction, that is, the longitudinal direction. Above the rib 24, a bolt hole 25 for inserting a head bolt (not shown) connecting the cylinder block 2 and the cylinder head 7 is provided. That is, the ribs 24 and the bolt holes 25 overlap when viewed in plan as shown in FIG. 3, and the ribs 24 secure the rigidity around the bolt holes 25 when the head bolts are tightened.

FIG. 4 is a view from the top of the top deck 26 of one bank of the cylinder block 2, and the narrowest portion between the cylinders on the top of the top deck 26 has an adjacent cylinder. A rectangular cooling water opening 27 communicating with the water jacket 20 is provided. Further, a communication passage 28 communicating with a blow-by gas passage (not shown) provided on the cylinder head 7 side is provided at a position symmetrical with respect to the cooling water opening 27 in the lateral direction. Furthermore, three elongated curved cooling water openings 29a, 29b and 29c are provided around the cylinder bores 4 of the cylinders at both ends of the bank in the top deck 26, and both longitudinal side portions of the middle cylinder bore 4 are provided. Are provided with openings 29d and 29e for cooling water on an arc, respectively, and communicate with the water jacket 20a on the cylinder head 7 side.

Further, as shown in FIG. 1, a shielding plate 30 is attached so as to cover the entrance to the blow-by gas passage 21 above the crank chamber 3. The operation of the above structure will be described. The blow-by gas leaked from the combustion chamber 8 through the space between the piston ring and the cylinder wall enters the crank chamber 3. Since the lubricating oil is stored in the crank chamber 3, the blow-by gas is mixed with the oil mist in the crank chamber 3. Blow-by gas
The gas is recovered and introduced into the combustion chamber 8 through the intake system to be burned. However, since it is not preferable that oil mist is mixed therein, it is preferable to remove the blow-by gas as much as possible during the recovery process. From this viewpoint, a shield plate 30 for removing oil mist is provided at the entrance from the crank chamber 3 to the blow-by gas passage 21. Oil mist particles have a different inertial mass from blow-by gas,
By colliding with the shielding plate 30, the gas is separated from the blow-by gas. A rib 24 protrudes from the blow-by gas passage 21 at an intermediate portion of the inter-cylinder region. In the structure of the present example, the blow-by gas flows in the blow-by gas passage 21 in the cylinder arrangement direction, that is, in the vertical direction.

Therefore, the ribs 24 protrude in the blow-by gas passage 21 in a direction in which the flow of the blow-by gas is blocked. . The oil adhering to the wall is returned into the crank chamber 3 through the communication passage 23. The cooling water opening 27 around the combustion chamber 8 of the engine is formed in the upper part of the middle deck 19, but can provide a sufficient cooling effect.

Another embodiment of the present invention will be described with reference to FIGS. Components having the same structure as the previous example are denoted by the same reference numerals, and detailed description is omitted. FIG. 5 shows a plan view similar to that shown in FIG. 4 of the previous example. FIG. 6 shows a cross-sectional view similar to FIG. 1 of the previous example. 5 and 6, the cylinder block 2
In the lower part, an oil pan 31 for storing engine oil
Are attached by bolts 32. An oil return passage 34 that communicates with the blow-by gas passage 21 is provided outside the crankcase wall 33 that defines the crankcase 3. The oil return passage 34 is formed on the outer wall of the cylinder block 2 so as to collect oil in the cylinder head cover to the oil pan 31 and communicates with the oil pan 31 from outside the crank chamber wall 33. Referring to FIGS. 5 and 7, the blow-by gas of the crank chamber 3 is supplied to the oil separator (not shown) provided on the cylinder head cover 16 through the blow-by gas passage 21 of the cylinder block 2 at one end in the cylinder arrangement direction. A blow-by gas take-out passage 35 for guiding is formed, and a take-out port 36 communicating with a take-out passage (not shown) of the cylinder head 7 is formed in the top deck 26 of the cylinder block 2.
Therefore, the blow-by gas filled in the crank chamber 3 is introduced into the blow-by gas passage 21 through the entrance of the lower deck 22 provided in the shielding plate 30. The blow-by gas passages 21 provided around the cylinder bores 4 of the respective cylinders communicate with each other in the cylinder arrangement direction, that is, in the vertical direction, and form a blow-by gas take-out passage 35 formed at one end of the cylinder block 2 in the vertical direction. After being introduced into an oil separator provided on the cylinder head cover through the cylinder and separating the oil, the oil is finally introduced into an intake system for combustion. The separated oil is returned to the oil pan 31 via the communication passage 23 and the oil return passage 34. In the engine 1 of the present embodiment, the cylinders are arranged in an inclined state, so that the passage 34 communicating with the crank chamber 3 and the blow-by gas passage 21 on the lower exhaust side mainly functions for oil return. .

[0014]

According to the present invention, a blow-by gas passage is provided in the lower portion of the cylinder block so as to exhibit an oil separator function, so that a compact blow-by gas processing mechanism can be provided. Further, overcooling of the engine can be prevented. Further, the oil separating performance can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a cylinder block of an engine according to one embodiment of the present invention;

FIG. 2 is a sectional view of the cylinder block of the engine in the same direction as FIG. 1 and at a different position;

FIG. 3 is a sectional view taken along line AA in FIG. 2;

FIG. 4 is a plan view of a top deck of the cylinder block of FIG. 1;

FIG. 5 is a plan view of a top deck of a cylinder block according to another embodiment of the present invention;

6 is a sectional view of the cylinder block of FIG. 5, wherein a sectional view of the left bank is a sectional view taken along line BB in FIG. 5, a right bank is a transverse sectional view taken along a center line of the cylinder bore,

FIG. 7 is a sectional view of the cylinder block taken along line CC of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 engine 2 cylinder block 3 crank chamber 4 cylinder bore 5 piston 7 cylinder head 16 cylinder head cover 20 water jacket 21 blow-by gas passage 23 communication passage 24 rib 35 blow-by gas removal passage 36 removal port

──────────────────────────────────────────────────続 き Continued on the front page (72) Noriyuki Iwata, Inventor 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Co., Ltd. −54223 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01M 13/04 F01M 13/00

Claims (2)

(57) [Claims] A space formed around a cylinder bore in which a piston slides is divided into upper and lower parts, an upper space constitutes a water jacket through which engine cooling water flows, and a lower space constitutes a blow-by. A blow-by gas passage through which gas flows is provided, and a rib protruding into the blow-by gas passage is provided below a bolt hole for inserting a head bolt provided near a partition wall that partitions between the cylinder bores. Cylinder block structure for multi-cylinder engine. 2. A blow-by gas passage formed in the cylinder block has a communication portion communicating with a blow-by gas passage provided in a cylinder head, and a bolt hole of the head bolt is provided in the communication portion. The cylinder block structure for a multi-cylinder engine according to claim 1, wherein the cylinder bore is disposed in an inclined state.