JPH0626397A - Cylinder block construction for engine - Google Patents

Abstract

PURPOSE:Fo eliminate a difference in cooling effect between cylinders and also give even cooling effect. CONSTITUTION:A water jacket 20 in a cylinder block 2 is provided independently for each cylinder, and a rectangular cooling water opening which is connected to the water jacket 20 in an adjacent cylinder is provided on a top deck 26 between bores and at the narrowest section. Because the water jacket is provided independently for each cylinder, evenness of cooling can be promoted and also, because connection between the cylinders is allowed, a difference in cooling water flow between the cylinders can be reduced. Thus a difference in cooling between the cylinders can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an engine cylinder block in which an independent water jacket is formed for each cylinder.

[0002]

2. Description of the Related Art In a multi-cylinder engine, it is known that a water jacket provided around the cylinder bore of a cylinder block is provided independently for each cylinder in order to promote uniform cooling of each cylinder (for example, JP-B-51). -4
5732).

[0003]

If the water jacket as described above is constructed completely independently for each cylinder, there is a problem that the flow of cooling water becomes uneven and the cooling effect varies between the cylinders. . Therefore, in view of the above circumstances, an object of the present invention is to provide a structure of a cylinder block which can eliminate the difference in the cooling effect between the cylinders and can provide a structure of a water jacket which can provide a uniform cooling effect. Is to provide.

[0004]

In order to solve the above problems, the present invention comprises the following configurations. That is, in the cylinder block of the present invention, a water jacket separately formed around the cylinder bore for each cylinder and a water jacket around the cylinder bores of the adjacent cylinders provided at the upper part of the cylinder block are provided in the inter-bore region between both cylinders. It is characterized in that a communication passage communicating with each other is formed. Preferably,
The communication passage opens to the upper surface of the top deck of the cylinder block.

[0005]

In the structure of the conventional cylinder block, the water jackets provided around the cylinder bores via the bore wall are independently configured, and therefore, the communication of the cooling water with each other is cut off. With such a configuration, it is possible to achieve uniform cooling for the cylinder, but there is a risk that a difference between the cylinders will occur. In the configuration of the present invention, the water jackets of the adjacent cylinders are made to communicate with each other through the communication passage in the interbore region, that is, in the region where the interval between the adjacent cylinders is the smallest. In other words, the communication passage is formed on the cylinder block center line in the cylinder row direction obtained by connecting the center lines of the cylinders. With this configuration, the cooling water can flow through the water jacket of each cylinder through this communication passage, so that there is no flow rate difference between the water jackets of the cylinders and the cooling difference between the cylinders can be reduced. When this communication passage is configured to open to the top deck of the cylinder block, the core forming the water jacket of the adjacent cylinder at the time of casting the cylinder block is integrated to form the skirting board holding the core. The core blocks forming the water jackets of the respective cylinders can be improved in positional accuracy and the cylinder block manufacturing accuracy can be improved.

[0006]

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 6-cylinder engine, and includes a cylinder block 2 that intersects in a V-shape and has two banks each having three cylinders. Below the cylinder block 2, a crank chamber 3 common to each bank is formed. A cylinder bore 4 extending from the crank chamber 3 to the inside of each bank is formed, and in this cylinder bore 4,
A piston 5 is slidably arranged, and this piston 5 is connected via a connecting rod 6 to a crank shaft (not shown) extending in the crank chamber 3 in the cylinder arrangement direction. A cylinder head 7 is combined with an upper portion of the cylinder block 2, and a recess formed in an upper portion of the cylinder bore 4 and a lower portion of the cylinder head 7 forms a combustion chamber 8. In the combustion chamber 8,
The tip of the spark plug 9 projects. A valve mechanism 10 is arranged in a space above the cylinder head 7, and the valve mechanism 10 includes a cam shaft 1 having a cam 11.
2. Rocker shaft 1 supporting the rocker arm 13
4. Drive the valve device 15. The upper space of the cylinder head 7 is covered by the cylinder head cover 16. An intake passage 17 and an exhaust passage 18 are connected to the cylinder head 7, respectively.

A space portion extending in the direction of the cylinder bore 4 is provided around the cylinder bore 4 of the cylinder block 2, and the space portion is vertically divided by the middle deck 19. The upper space constitutes the water jacket 20 through which the engine cooling water flows, and the lower space constitutes the combustion chamber 8
To form a blow-by gas passage 21 through which a blow-by gas composed of gas leaking into the crank chamber 3 mainly from between the piston ring and the cylinder wall flows. The water jacket 20 is provided independently for each cylinder so as to form a double cylinder structure with the outer wall 4b surrounding the cylinder wall 4a. The lower end of the blow-by gas passage 21 formed in the cylinder block 2 is partitioned by the lower deck 22 that constitutes the lower end of the cylinder bore 4. Referring also to FIG. 2, the lower portion of the blow-by gas passage 21 communicates with the crank chamber 3 via the communication passage 23. Further, in the blow-by gas passage 21, a rib 24 projects in a direction orthogonal to the vertical direction, that is, in the horizontal direction at a position that divides the interbore region in the cylinder arrangement direction, that is, the vertical direction. This rib 2
Above the cylinder 4, there are a cylinder block 2 and a cylinder head 7.
A bolt hole 25 is provided for inserting a head bolt (not shown) for coupling the. FIG. 3 is a top view of the top deck 26 of one bank of the cylinder block 2, and the water jackets of the adjacent cylinders are provided in the narrowest portion between the bores on the top surface of the top deck 26. A rectangular cooling water opening 27 that communicates the 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 symmetrical position with respect to the cooling water opening 27 in the lateral direction. Further, in the top deck 26, three elongated curved cooling water openings 29a, 29b and 29c are provided around the cylinder bores 4 at both ends, and arcuate arcs are formed on both sides in the vertical direction of the middle cylinder bore 4. Cooling water openings 29d and 29e are provided respectively and communicate with the water jacket 20a on the cylinder head 7 side.

Blow-by gas passage 21 from crank chamber 3
A shield plate 30 for removing oil mist is provided at the entrance to the. A cooling water introducing passage 31 for introducing cooling water to the water jacket 20 of the cylinder block 2 is provided at the base portion between both banks. In the structure described above, the cooling water is introduced from the cooling water introduction passage 31 into the water jacket 20 independently provided for each cylinder of the cylinder block 2. The cooling water introduced into the water jacket 20 cools the cylinder wall 4 a and is adjacent to the water jacket 20 of the cylinder via the cooling water opening 27.
And to the water jacket 20a on the cylinder head 7 side through the cooling water opening 29.

[0009]

According to the present invention, since the water jacket is provided independently for each cylinder, uniform cooling can be promoted, and communication between the cylinders is allowed. It is possible to reduce the cooling water distribution gap,
Therefore, the cooling gap between the cylinders can be reduced.
Further, by forming the communication passage so as to open on the top deck, the communication passage can be used for arranging a skirting board, and by doing so, the manufacturing accuracy of the cylinder block can be improved. Also occurs.

[Brief description of drawings]

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

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

FIG. 3 is a plan view of the top deck shown in FIG.

[Explanation of symbols]

 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 27 Cooling Water Opening 29 Cooling Water Opening 31 Cooling Water Introducing

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenji Kashiyama 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Motor Corporation

Claims (2)

[Claims] 1. A water jacket, which is formed independently around the cylinder bore for each cylinder, and a water jacket around the cylinder bores of adjacent cylinders provided on the upper part of the cylinder block are connected in the region between the bores. A cylinder block structure for an engine, characterized in that a passage is formed. 2. The cylinder block structure for an engine according to claim 1, wherein the communication passage is open to an upper surface of a top deck of the cylinder block.