Water jacket

Abstract

A water jacket includes: a cooling channel through which a coolant flows, the cooling channel being formed in a cylinder block in which a plurality of cylinders are formed such that the cooling channel is positioned outside the cylinders; and a cooling groove (slit) through which the coolant flows, the cooling groove being formed between adjacent ones of the cylinders. When a slit end portion is viewed in sectional view in a direction in which the cylinders are arranged, the slit end portion and a cylinder-block inner wall are continuous with each other via an inclined portion inclined so as to become thicker toward the cylinder-block inner wall.

Claims

1. A water jacket comprising: a cooling channel through which a coolant flows, the cooling channel being disposed in a cylinder block in which a plurality of cylinders are formed such that the cooling channel is positioned outside the cylinders; and a cooling groove through which the coolant flows, the cooling groove being disposed between adjacent ones of the cylinders, wherein the cooling groove comprises a slit end portion at an inner wall of the cooling channel, and when the slit end portion of the cooling groove is viewed in sectional view perpendicular to a direction in which the cylinders are arranged, the slit end portion of the cooling groove and the inner wall of the cooling channel are continuous with each other via an inclined portion inclined downward from the slit end portion of the cooling groove toward the inner wall of the cooling channel.

2. The water jacket according to claim 1, wherein in a plan view, a first curved side surface, a flat wall surface, and a second curved side surface are continuous with each other between the adjacent ones of the cylinders, the first curved side surface extending so as to be curved from a position closer to a side wall of one of the adjacent ones of the cylinders, the flat wall surface being parallel to the direction in which the cylinders are arranged and extending toward the other of the adjacent ones of the cylinders from a side edge of the first curved side surface, the second curved side surface extending so as to be curved from a side edge of the flat wall surface toward the other of the adjacent ones of the cylinders, and the cooling groove is disposed at the flat wall surface.

3. The water jacket according to claim 1, wherein the inclined portion is inclined downward toward the outside of cylinders.

4. The water jacket according to claim 3, wherein, in a plan view, the inclined portion becomes wider toward the outside of cylinders.

5. The water jacket according to claim 1, wherein, in the sectional view, the inclined portion includes a curved portion.

6. The water jacket according to claim 1, wherein, in the sectional view, the inclined portion includes an upper-end curved portion and a lower-end curved portion, the lower-end curved portion being continuous with the inner wall of the cooling channel.

7. The water jacket according to claim 6, wherein, in the sectional view, the upper-end curved portion has a concave-curved shape and the lower-end curved portion has a convex-curved shape.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The advantages of the disclosure will become apparent in the following description taken in conjunction with the following drawings.

(2) FIG. 1 is a diagram illustrating a cylinder block including a water jacket of an embodiment of the present disclosure.

(3) FIG. 2 is a perspective view illustrating an end portion of a slit of the embodiment.

(4) FIG. 3 is a sectional view illustrating an inclined portion of the embodiment.

(5) FIG. 4 is a plan view illustrating the end portion of the slit of the embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(6) A cylinder block including a water jacket of an embodiment of the present disclosure will be described with reference to the drawings.

(7) Referring to FIG. 1, a cylinder block 1 of an internal combustion engine of the embodiment includes four cylinder liners 2, which correspond to cylinders of the present disclosure, a cylinder block body 3, which holds the cylinder liners 2, and a water jacket 4, which is disposed in the cylinder block body 3 so as to cover side surfaces of the cylinder liners 2.

(8) The water jacket 4 includes a cooling channel 4c. The cooling channel 4c is defined by a cylinder-block inner wall 4a, which covers the cylinder liners 2, and a cylinder-block outer wall 4b, which is formed on the outside in a radial direction of each of the cylinder liners 2 so as to face the cylinder-block inner wall 4a with a space therebetween. Coolant (cooling water) flows in the water jacket 4 in a direction in which the cylinder liners 2 are arranged.

(9) Slits 5 (cooling grooves) are each disposed between corresponding ones of the cylinder liners 2. The slits 5 connect left and right regions into which the cooling channel 4c is divided by the cylinder liners 2 such that coolant can flow through the slits 5. Referring to FIG. 2, a slit bottom 5a, which is a bottom of the slit 5, is curved to avoid stress concentration.

(10) Referring to FIGS. 2 and 3, when a slit end portion 5b, which is an end portion of the slit 5, is viewed in sectional view in the direction in which the cylinder liners 2 are arranged illustrated in FIG. 3, the slit end portion 5b and the cylinder-block inner wall 4a of the cooling channel 4c are continuous with each other via an inclined portion 6, which is inclined so as to become thicker toward the cylinder-block inner wall 4a. The inclination angle of the inclined portion 6 is larger than the draft angle of a die for the cylinder block 1. An upper-end curved portion 6a of the inclined portion 6, which is closer to the slit 5, and a lower-end curved portion 6b of the inclined portion 6, which is closer to the cylinder-block inner wall 4a, are disposed close to each other at a distance of, for example, 3 to 6 mm.

(11) Referring to FIG. 4, a first curved side surface 11, a flat wall surface 12, and a second curved side surface 13 are continuous with each other between adjacent cylinder liners 2. The first curved side surface 11 extends so as to be curved such that the first curved side surface 11 is recessed from a position closer to the cylinder-block inner wall 4a covering one of the adjacent cylinder liners 2. The flat wall surface 12 is parallel to the direction in which the cylinder liners 2 are arranged and extends toward the other of the adjacent cylinder liners 2 from a side edge of the first curved side surface 11. The second curved side surface 13 extends so as to be curved from a side edge of the flat wall surface 12 toward the cylinder-block inner wall 4a covering the other of the adjacent cylinder liners 2.

(12) The slit 5 is disposed such that the slit end portion 5b is positioned at the flat wall surface 12.

(13) In the cylinder block 1 including the water jacket 4 of the embodiment, the slit end portion 5b and the cylinder-block inner wall 4a are continuous with each other via the inclined portion 6, and the thermal stress and the compressive stress generated at the slit 5 are dispersed via the inclined portion 6. Thus, it is possible to reduce the stress generated at the cylinder block 1 even when the slit 5 linked to the cooling channel 4c is disposed between adjacent cylinder liners 2.

(14) In the embodiment, the slit 5 is disposed such that the slit end portion 5b is positioned at the flat wall surface 12. Thus, thermal stress and compressive stress are unlikely to concentrate on the slit 5 compared with the case in which a slit end portion is positioned at a curved surface. Accordingly, it is possible to reduce the stress generated at the cylinder block 1 even when the slit 5 linked to the cooling channel 4c is disposed between adjacent cylinder liners 2.

(15) In the embodiment, the configuration in which all the slits 5 are connected to the cylinder-block inner wall 4a via the corresponding inclined portions 6 and are positioned at the corresponding flat wall surfaces 12 is described, but the configuration of the water jacket in the present disclosure is not limited thereto. For example, a configuration in which some slit end portions are connected to an inner wall of a cooling channel via the corresponding inclined portions or a configuration in which some slit end portions are positioned at the corresponding flat wall surfaces also enables an operational effect of stress reduction of the present disclosure to be achieved.

(16) In addition, in the embodiment, the configuration in which three slits 5 are included is described, but the configuration of the slits in the present disclosure is not limited thereto. For example, the number of the slits may be one, two, or four or more. Although a specific form of embodiment has been described above and illustrated in the accompanying drawings in order to be more clearly understood, the above description is made by way of example and not as limiting the scope of the invention defined by the accompanying claims. The scope of the invention is to be determined by the accompanying claims. Various modifications apparent to one of ordinary skill in the art could be made without departing from the scope of the invention. The accompanying claims cover such modifications.