JP5946270B2 - Cylinder block water jacket structure - Google Patents

Description

  The present invention relates to a water jacket for cooling an internal combustion engine (hereinafter referred to as “engine”), and more particularly to a water jacket structure of a cylinder block.

  The engine explosively burns fuel inside the cylinder, moves the piston, and converts the movement of the piston into rotation of the crankshaft to obtain driving force. Accordingly, the periphery of the combustion chamber in the cylinder becomes high temperature, so that a cooling structure is provided. In the water-cooled cooling structure, a water jacket is provided around the combustion chamber, which is mainly a heat generation source, and cooling water is circulated there.

  Since the combustion chamber is composed of a cylinder head and a cylinder block, a water jacket is formed in both members. The water jacket is a passage for circulating cooling water. Therefore, it is necessary to provide an inlet and an outlet. However, it is not preferable to provide a cooling water inlet / outlet in the cylinder head itself, which leads to an increase in size of the cylinder head. Therefore, the cooling water inlet / outlet is provided on the cylinder block side, and the cooling water to the cylinder head is supplied from the cylinder block side.

  On the other hand, the cylinder block is made of an aluminum alloy to reduce the weight of the engine. When a cylinder block is manufactured from an aluminum alloy, it is manufactured by die casting. In die casting, it is necessary to pull out the mold after molding. Therefore, when a water jacket is formed on the cylinder block by die casting, an open deck type water jacket having a water jacket opened on the deck surface is obtained.

  In this type of water jacket, only a space for cooling water is formed around the cylinder, and a flow path is not particularly provided. Therefore, if the flow of the cooling water in the cylinder block and the supply of the cooling water to the cylinder head are performed only by the cooling water hydraulic pressure, a part of the cooling water is retained and sufficient cooling is performed. There is no problem.

  In addition, it is the periphery of the combustion chamber that requires cooling. Since the combustion chamber is the center of the heat source, the temperature gradient depending on the distance from the combustion chamber becomes lower from the upper part of the cylinder, which is around the combustion chamber, to the lower part of the cylinder. Then, the upper part of the cylinder is more deformed by heat than the lower part of the cylinder, and when viewed as a whole cylinder, the upper part is opened.

  The piston ring is designed in accordance with the size of the upper part of the cylinder in a thermally deformed state in order to improve the airtightness in the portion close to the combustion chamber. Therefore, in the lower part of the cylinder, the friction with the piston is increased and the mechanical loss is increased. If the upper part of the cylinder is cooled from the lower part to keep the amount of thermal deformation constant for the entire cylinder, such mechanical loss can be avoided.

  On the other hand, the oil supply source is on the crank chamber side. Therefore, the oil is supplied from the lower part of the cylinder. However, if the lower part of the cylinder is overcooled, the oil will thicken and will not be sufficiently lubricated, causing mechanical loss.

  That is, it is necessary that the flow of the cooling water in the cylinder block flows as easily as possible to the cylinder head side, which is the central portion of the combustion chamber, and not to be overcooled in the lower portion of the cylinder.

  In the cylinder block using an aluminum alloy, it has already been described that the mold must be pulled out after molding, but this also means that it is not easy to form the uneven shape in the water jacket. Therefore, how to control the flow of the cooling water in the water jacket of the cylinder block formed as a simple space becomes a problem.

  To solve this problem, for example, as disclosed in Patent Document 1, a method of inserting a filler called a water jacket sleeve into a water jacket is disclosed. This is to fill the lower part on the crank chamber side of the space constituting the water jacket of the cylinder block with a material such as nylon 66 that swells with water. With this water jacket sleeve, the flow of the cooling water is deteriorated on the lower side of the cylinder, and the cooling water flows exclusively on the cylinder head side.

Japanese Utility Model Publication No. 60-164645

  However, the water jacket sleeve is a separate member for the engine, leading to an increase in the number of parts. Moreover, since the assembly man-hour increases, it becomes a cause of a cost rise. Further, since the water jacket of the cylinder block is one space, a pressure difference from the cooling water introduction port hardly occurs, and an effective cooling water flow cannot always be formed by installing the water jacket sleeve.

The present invention has been conceived in view of the above problems. More specifically, the present invention provides:
A water jacket is provided around the cylinder, the water jacket is open to the cylinder head side, and a cylinder block provided with a cooling water intake port from the water pump on either side of the cylinder block front-rear direction, which is the crankshaft direction . The structure of the water jacket,
The cooling water intake is
In the opening portion outside the cylinder block, the lower opening width is narrower than the upper opening width, and the lower side is moved toward the center side of the cylinder from the upper side to the lower side along the central axis direction of the cylinder. The water jacket structure of the cylinder block is characterized in that a water outlet opening to the inside of the cylinder block is formed on the inclined surface formed in the cylinder block.

  In the water jacket structure of the present invention, the shape of the opening portion on the outside of the cylinder block is formed so that the opening width on the lower side is narrowed. Therefore, when the cooling water passes, a pressure difference is generated in the upward direction. Head in the direction. Further, since the cooling water is introduced with an upward flow from the opening provided below in the water jacket, the flow rate to the cylinder head side can be increased. Further, at the same time, it is possible to avoid overcooling on the crank chamber side of the cylinder block.

  Further, there is no need to use a water jacket sleeve, and an increase in cost can be suppressed by reducing the number of parts and the number of assembly steps.

It is a figure which shows the external appearance of the cylinder block which has the water jacket structure of this invention. FIG. 2 is a partially enlarged view of FIG. 1. It is a figure which shows the water channel from the intake of a cooling water to the inside of a water jacket. It is a figure which shows the partial top view and sectional drawing of FIG. It is a figure explaining the flow of cooling water.

  The present invention will be described below with reference to the drawings. The following description exemplifies an embodiment of the present invention, and the following embodiment may be modified without departing from the gist of the present invention.

  FIG. 1 shows the appearance of a cylinder block 10 having a water jacket structure 1 of the present invention. Although FIG. 1 shows the case of three cylinders, the number of cylinders is not particularly limited. Arrow 11 indicates the direction of the crankshaft. This crankshaft direction 11 is the front and rear of the cylinder block 10. In addition, the direction in which the opening of the cylinder 12 is formed is an upward direction, and the opposite side is a downward direction. A cylinder head is mounted on the upper side of the cylinder block. The deck surface 14 is a butting surface between the cylinder block and the cylinder head.

  There is a gap between the cylinder 12 and the cylinder block 10. This is the water jacket 16 portion. That is, the water jacket 16 portion is open to the cylinder head side. A gap between the cylinder 12 and the cylinder block 10 is referred to as a water jacket opening width 16w. The present invention can be suitably used mainly for an open deck type cylinder block.

  A timing chain cover is attached to one end of the cylinder block 10 in the front-rear direction. The side to which the timing chain cover is attached is the front side 10f of the cylinder block, and the opposite side is the rear side 10b. In the water jacket structure 1 of the present invention, a cooling water intake 20 is formed on the front side 10 f of the cylinder block 10. This is because a gear or the like (not shown) for driving the timing chain is placed on the front side 10f, so that a water pump (not shown) is easily provided. However, it may be arranged on the rear side 10b. Therefore, the cooling water intake 20 is provided on either surface in the front-rear direction.

  The water jacket opening width 16w is wide at the portion where the cooling water intake 20 is provided. This portion of the water jacket is the enlarged water jacket 17, and the water jacket opening width of this portion is 17w.

  The cooling water intake 20 is formed in an inverted triangular shape. This may not be an inverted triangle in particular as long as the opening width in the downward direction is narrowed. For example, a trapezoid whose upper side is longer than the lower side or other polygons may be used. Moreover, the shape which processed the part of the corner with the curve may be sufficient. Bolt fastening holes 18a, 18b, and 18c are formed in close proximity at two locations above and one below the intake port 20.

  FIG. 2 shows an enlarged view of the vicinity of the cooling water intake 20 of FIG. In the present specification, the shape of the intake 20 is an inverted triangle. The intake port 20 is formed flush with the mounting surface 10m with the chain cover on the cylinder block front side 10f. Further, the lower end 20 c of the intake port 20 is formed closer to the center side of the cylinder block 10 than the upper end 20 a and is formed closer to the center side than the inner surface 17 i of the enlarged water jacket 17. In addition, although the other upper end 20b shows the example located below the upper end 20a, it is not necessarily limited.

  Reference is now made to FIG. FIG. 3 shows only the water channel 21 from the cooling water intake 20 to the back. FIG. 3A is a view from the intake 20 side. FIG. 3B is a view seen from the side surface of the cylinder block 10 (in the direction of reference numeral 10s in FIG. 1). A mounting surface 10m with the chain cover is a surface indicated by an arrow.

  FIG. 3C is a view seen from above the cylinder block 10. With reference to FIG.3 (b), the intake 20 of the cooling water forms the cut surface 25 toward the edge 24 which opposes from the one side 23 of one bottom face of a triangular prism as a whole. Here, the intake port 20 is the other bottom surface 26, and the bottom surface side where the cut surface 25 is provided corresponds to the back when viewed from the intake port 20 side.

  Referring to FIG. 3A, the lower end 20 c of the intake port 20 is formed closer to the center side of the cylinder block 10 than the inner surface 17 i of the enlarged water jacket 17. That is, the inclined surface 27 is formed from the upper end 20 a to the lower end 20 c of the intake port 20. Here, assuming that the ridge 28 (see FIG. 3C) of the upper end 20a is formed along the inner surface 17i (see FIG. 1) of the enlarged water jacket 17, the enlarged water jacket 17 is located behind the water channel 21. A water outlet 29 communicating with the inside is formed.

  Reference is again made to FIG. As described with reference to FIG. 3, the intake port 20 is formed with an inclined surface 27 from the upper end 20 a to the lower end 20 c toward the center of the cylinder block 10. Therefore, protrusions are formed inside the enlarged water jacket 17 by the amount corresponding to the extraction of the water channel 21 shown in FIG. This is because, when viewed from the mold of the cylinder block 10, the tip is thin and the base side is thick, so that the mold can be pulled out without any trouble. And after drawing out a metal mold | die and a punching die, the water outlet 29 can be formed by cutting toward the perpendicular downward direction along A of a deck surface.

  4A shows a plan view of the cylinder block 10 as viewed from above, and FIG. 4B shows a cut surface taken along the line BB. The enlarged water jacket opening width 17w in the periphery where the intake port 20 is formed is formed wider than the water jacket opening width 16w in other portions. Further, the slope 30 is the slope 30 of FIG. A surface 31 that appears as a vertical surface looks at a surface obtained by cutting a part of the cut surface 25 in FIG. The water outlet 29 opens at an angle in the upward direction toward the inside of the enlarged water jacket 17 (see also FIG. 2).

  Next, the operation of the water jacket structure 1 configured as described above will be described. FIG. 5 is the same diagram as FIG. Referring to FIG. 5A, the intake port 20 is formed such that the lower opening width 32 is narrower than the upper opening width 33. Therefore, the cooling water flowing into the intake port 20 receives pressure on the lower side and flows upward. This flow runs up the slope 30. In other words, it flows upward. In FIG. 5B, this state is indicated by an arrow 34.

  The direction of the flow 34 is changed at the cut surface 25. At this time, since the cooling water collides with the cut surface 25 from below to above, the flow 34 further flows upward. Then, the water is discharged from the water outlet 29 into the enlarged water jacket 17. Moreover, since the upper part of the water outlet 29 is released earlier than the lower part (see FIGS. 5A and 5C), the cooling water discharged from the water outlet 29 is the upper part inside the enlarged water jacket 17 ( It is discharged with a flow toward the cylinder head side.

  Moreover, since the enlarged water jacket opening width 17w is formed wide inside the enlarged water jacket 17 in which the water outlet 29 is formed, the upward flow of the cooling water is not disturbed by the outer wall surface of the cylinder 12. Therefore, by forming the cooling water inlet to the cylinder head in the enlarged water jacket opening width 17w, the flow of the cooling water to the cylinder head can be improved.

  Further, in order to supply the cooling water from the enlarged water jacket opening width 17w to the other water jacket 16 portion of the cylinder block 10, the water passage passes through a narrow passage (see C and D in FIG. 1). There must be. That is, in addition to the structure of the cooling water intake 20 of the present invention, the cooling water is discharged into a wide space in the enlarged water jacket 17 and the cooling water inlet is formed in the cylinder head arranged above the portion. Thus, it becomes easier to supply the cooling water to the cylinder head side.

  Moreover, since said method can be implemented without using another member, such as a water jacket sleeve, it is suitable also from a viewpoint of a number of parts and an assembly man-hour.

  The water jacket structure of the cylinder block of the present invention can be suitably used for an open deck type cylinder block.

1 Water jacket structure 10 Cylinder block 10b Rear side of cylinder block 10f Front side of cylinder block 10m Mounting surface of cylinder block and chain cover 10s Side surface of cylinder block 11 Crank axis direction 12 Cylinder 14 Deck surface 16 Water jacket 16w Water jacket opening width 17 Enlarged water jacket 17w Enlarged water jacket opening width 17i (Inside of the enlarged water jacket) 18a, 18b, 18c Bolt fastening hole 20 Intake port 20a (Intake port) Upper end 20b Upper end 20c lower end 21 (from intake port) waterway 23 (from one bottom surface of triangular prism) one side 24 (opposite one side of 23) ridge 25 cut surface 26 other side Surface (inlet)
27 Inclined surface 28 Ridge (upper end) 29 Water outlet 30 Slope 31 Surface 32 Lower opening width 33 Upper opening width 34 Water flow flowing upward on the slope 30

Claims (1)

A water jacket is provided around the cylinder, the water jacket is open to the cylinder head side, and a cylinder block provided with a cooling water intake port from the water pump on either side of the cylinder block front-rear direction, which is the crankshaft direction . The structure of the water jacket,
The cooling water intake is
In the opening portion outside the cylinder block, the lower opening width is narrower than the upper opening width, and the lower side is moved toward the center side of the cylinder from the upper side to the lower side along the central axis direction of the cylinder. A water jacket structure for a cylinder block , wherein a water outlet opening to the inside of the cylinder block is formed on an inclined surface formed on the cylinder block.