JP2015190351A - Multicylinder internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve cooling performance for cooling inter-cylinder portions of a cylinder block.SOLUTION: A block jacket 5 is formed to surround a cylinder row, and an inter-cylinder communication hole 12 is formed in each intern-cylinder portion 10 in an inclined attitude for flowing cooling water from a recessed portion 11 of one jacket groove 7 to the recessed groove 11 of the other jacket groove 8. A head jacket 18 of a cylinder head is of a two-layer structure including a lower layer portion 16 and an upper layer portion 17, an inter-jacket communication passage 19 connecting the block jacket 5 with the lower layer portion 16 and an inter-layer communication passage 20 connecting the lower layer portion 16 to the upper layer portion 17 are located right above the recessed portion 11 of the other jacket groove 8. Since a strong upward flow from the block jacket 5 to the head jacket 18 causes a high negative pressure to act on an outlet 14 of the inter-cylinder communication hole 12, it is possible to increase a flow velocity of a flow of water and improve cooling performance for cooling the inter-cylinder portion 10 without increasing an inside diameter of the inter-cylinder communication hole 12 so as to widen the inter-cylinder portion 10.

Description

  The present invention relates to a multi-cylinder internal combustion engine.

  The cylinder block and the cylinder head of the internal combustion engine are cooled with cooling water. Therefore, in a multi-cylinder internal combustion engine, a block jacket is formed so as to surround the cylinder row in the cylinder block, and the cylinder head has a surface area. A head jacket is formed. In general, the block jacket and the head jacket are connected by a plurality of inter-jacket communication paths, and cooling water often flows to the cylinder head after cooling the cylinder block.

  The head jacket is configured in two upper and lower layers, and an example thereof is disclosed in Patent Document 1. When the head jacket is composed of two layers, the lower layer portion is connected by an interlayer communication passage, and the upper layer and the lower layer are connected by an interlayer communication passage. Cooling water is supplied from the block jacket, the lower layer of the head jacket, and the head jacket. It flows in the order of the upper layer and is sucked into the water pump via the radiator (or without going through it).

  On the other hand, the block jacket is formed outside the cylinder row so that the distance from the inner peripheral surface of each cylinder is substantially the same. For this reason, the block jacket sandwiches the cylinder row (the crank axis is sandwiched). 2) The two jacket grooves located on both sides are connected to each other, and the interval between the two jacket grooves is the narrowest (constricted) at a location between adjacent cylinders.

  In order to improve the uniformity of cooling of each cylinder, an inter-cylinder communication hole is formed between adjacent cylinders (inter-cylinder portion), and the cooling water is allowed to flow from one jacket groove to the other jacket groove. It has been proposed, and an example thereof is disclosed in Patent Document 2. In Patent Document 2, an inter-jacket communication path is disposed at the exit of the inter-cylinder communication hole.

Japanese Patent No. 4108868 JP 2012-225246 A

  Now, the area between the cylinders of the block jacket is thin and heat builds up, so the need for cooling is high. Therefore, it is preferable to increase the flow rate of the cooling water flowing through the inter-cylinder communication hole as much as possible. In this regard, when the inter-jacket communication passage is arranged at the outlet of the inter-cylinder communication hole as in Patent Document 2, the suction effect from the inter-jacket communication passage is exhibited, and the amount of water flowing through the inter-cylinder communication hole can be increased. .

  However, the cooling water that has flowed from below into the head jacket from the inter-jacket communication path spreads in the head jacket in the horizontal direction and the vertical direction (crank axis direction) perpendicular to the cylinder axis. It cannot be said that the flow rate is fast, and therefore, the effect of sucking up the cooling water in the inter-cylinder communication hole is limited, and it is estimated that the cooling performance of the inter-cylinder portion is not necessarily high.

Therefore, in order to increase the flow rate through the inter-cylinder communication hole, the inner diameter must be increased. However, the space between the cylinders must be widened to ensure the strength, and the cylinder block is increased in size. .

  The present invention has been made to improve the current situation.

  The present invention is an internal combustion engine comprising a cylinder block having a plurality of cylinders and a cylinder head fixed to the upper surface of the cylinder block. First, the cylinder block has a block jacket surrounding a cylinder row. An inter-cylinder communication hole that connects the block jackets located on both sides of the cylinder row is formed between the cylinders. The inter-cylinder communication hole is formed at one end. Is the cooling water inlet and the other end is the cooling water outlet.

  On the other hand, the cylinder head is formed in a state where the head jacket is divided into a plurality of upper and lower layers, the lowermost layer and the block jacket are connected by an inter-jacket communication path, and the layers adjacent to the upper and lower are interlayer communication paths Are connected. Further, the inter-jacket communication passage and the interlayer communication passage are arranged substantially directly above the vicinity of the outlet of the inter-cylinder communication hole.

  Here, “substantially directly above” means a state in which the outlet of the inter-cylinder communication hole, the communication path between the jackets, and the interlayer communication path are entirely or partially overlapped as viewed from the cylinder axial direction, and the inter-cylinder communication hole. Although the inter-jacket communication path and the interlayer communication path are slightly deviated from the outlet of the cylinder, both of the states include a state in which the coolant discharged from the inter-cylinder communication hole is close to the degree toward the inter-jacket communication path. That is, it means directly above or in the vicinity thereof.

  Normally, a plurality of inter-jacket communication passages are provided, but all of the plurality of inter-jacket communication passages may be arranged directly above the outlet of the inter-cylinder communication hole, or some inter-jacket communication passages may be provided. The passage may be disposed directly above the communication hole between the cylinders. Similarly, all of the interlayer communication paths may be disposed directly above the inter-jacket communication path, or a part thereof may be disposed substantially directly above the inter-jacket communication path.

  In addition, to describe the relationship between the block jacket and the head jacket, a single-system cooling type in which cooling water always flows from the block jacket to the head jacket may be used. A two-system cooling type that flows from the block jacket to the head jacket after completion of the warm-up operation may be used.

  In the present invention, since the inter-jacket communication passage and the interlayer communication passage are disposed substantially directly above the outlet of the inter-cylinder communication hole, the straightness of the cooling water flowing upward from the inter-cylinder communication hole is increased, and the cylinder The amount of cooling water sucked up (or pushed up) from the outlet of the communication hole can be increased. As a result, the suction action for the communication holes between the cylinders is also improved, so that the amount of water flowing through the communication holes between the cylinders can be increased without increasing the inner diameter of the communication holes between the cylinders. The cooling performance of the part can be improved.

It is a figure of the cylinder block which concerns on embodiment, (A) is the whole top view, (B) is the elements on larger scale of (A). It is II-II sectional view taken on the line of FIG.

Next, an embodiment of the present invention will be described with reference to the drawings. The present embodiment is applied to a three-cylinder internal combustion engine. For this reason, first to third three cylinders (cylinders) 2, 3, 4 are opened upward in the cylinder block 1. Further, an endless block jacket 5 surrounding the group of cylinders 2, 3, 4 is formed on the upper surface of the cylinder block 1. Needless to say, the cylinders 2, 3, 4 are aligned in the direction of the crank axis 6.

  Since the block jacket 5 surrounds the group of cylinders 2, 3, and 4, the first jacket groove 7 located on one side and the second jacket located on the other side sandwiching the group of cylinders 2, 3, and 4. It comprises a jacket groove 8 and both are continuous at the end of the cylinder row.

  A portion of the upper surface of the cylinder block 1 on one side of the first cylinder 2 and outside the block jacket 5 opens to one side surface 1a of the cylinder block 1 to form a first jacket groove 7 of the block jacket 5. A communicating coolant inlet 9 is open. Therefore, the cooling water flows into the first jacket groove 7 from the cooling water inlet 9, and is divided into two hands at the first jacket groove 7 and then merges at the second jacket groove 8.

  Although not shown, the cooling water inlet 9 is connected to a discharge port of the water pump. A main gallery may be provided inside the cylinder block so that the main gallery communicates with the block jacket 5.

  The inner peripheral surfaces of the jacket grooves 7 and 8 constituting the water jacket 5 are generally at equal intervals to the cylinders 2, 3 and 4. Therefore, the gap between the jacket grooves 7 and 8 is the narrowest at the positions of the adjacent cylinders 2, 3 and 4. In other words, the jacket grooves 7 and 8 are recessed portions (constriction portions) 11 that enter the inter-cylinder portion 10 between the adjacent cylinders 2, 3, and 4. As shown in FIG. 2, an inter-cylinder communication hole 12 is formed in the inter-cylinder portion 10 in a direction orthogonal to the crank axis 6.

  In this case, the inter-cylinder communication hole 12 is inclined so that the inlet 13 opened to the recessed portion 11 of the first jacket groove 7 is low and the outlet 14 facing the recessed portion 11 of the second jacket groove 8 is high. Yes. Therefore, the cooling water flows obliquely upward through the inter-cylinder communication hole 12. The outlet 14 may be opened in the recessed portion 11 of the second jacket groove 8 as shown by a solid line in FIG. 2, or the recessed portion 11 of the second jacket groove 8 as shown by a one-dot chain line in FIG. Instead of opening, the upper surface of the inter-cylinder portion 10 may be opened.

  A head jacket 18 composed of a lower layer portion 16 and an upper layer portion 17 is formed inside the cylinder head 15 fixed to the cylinder block 1, and the lower layer portion 16 of the head jacket 18 and the outlet of the inter-cylinder communication hole 12 are formed. Are communicated by an inter-jacket communication passage 19, and the lower layer portion 16 and the upper layer portion 17 of the head jacket 18 are communicated by an interlayer communication passage 20.

  When the inter-cylinder communication hole 12 opens in the recessed portion 11 of the second jacket groove 8 as shown by a solid line, the inter-jacket communication passage 19 opens in the recessed portion 11 of the second jacket groove 8, The communication hole 12 and the communication path 19 between the jackets communicate with each other via the recessed portion 11. That is, the inter-jacket communication passage 19 and the interlayer communication passage 20 are positioned substantially directly above (in the vicinity of) the outlet 14 of the inter-cylinder communication hole 12. More precisely, the lower end of the inter-jacket communication passage 19 is positioned on the extended line of the inter-cylinder communication hole 12, and the interlayer communication passage 20 is positioned directly above the inter-jacket communication passage 19.

When the outlet of the inter-cylinder communication hole 12 does not open into the recessed portion 11 of the second jacket groove 8, as shown by the one-dot chain line in FIGS. 1B and 2, the interlayer communication path 20 and the inter-jacket communication path 19 just above. When the inter-cylinder communication hole 12 is opened on the upper surface of the inter-cylinder portion 10, the inter-jacket communication passage 19 may be communicated only with the outlet 14 of the inter-cylinder communication hole 12, or a part of the second jacket groove 8. It may communicate with the recessed portion 11. Further, the outlet 14 of the inter-cylinder communication hole 12 may be opened on both the upper surface of the inter-cylinder portion 10 and the recessed portion 11 of the second jacket groove 8.

  When the inter-jacket communication passage 19 is communicated with the recessed portion 11 of the block jacket 5, the inter-jacket communication passage 19 can be provided only near the inter-cylinder communication hole 12, but as shown by a circle in FIG. It is preferable to provide a plurality of other locations such as near the end of the second jacket groove 8. Further, it is preferable to provide the interlayer communication path 20 at a place other than the portion directly above the inter-jacket communication path 19, and the other interlayer communication path 20 has a jacket sandwiching the crank axis 6 as shown by a triangle in FIG. It can be provided on the opposite side of the group of intercommunication passages 19.

  In the above configuration, since the inter-jacket communication path 19 and the interlayer communication path 20 are arranged in series up and down, the flow of the cooling water from the block jacket 5 to the head jacket 18 is imparted with strong straightness and strong. Become a flow. Therefore, a strong negative pressure acts on the inter-cylinder communication hole 12 by the water flow flowing toward the head jacket 18, and the flow rate of the cooling water flowing through the inter-cylinder communication hole 12 can be increased.

  As a result, the cooling performance of the inter-cylinder part 10 is improved without increasing the inner diameter of the inter-cylinder communication hole 12 and increasing the distance between the inter-cylinder parts 10 (that is, without increasing the size of the cylinder block 1). Demonstrates effects such as blow-by gas suppression by ensuring roundness. In particular, when the outlet of the inter-cylinder communication hole 12 is opened on the upper surface of the inter-cylinder portion 10 as indicated by the alternate long and short dash line, one inter-jacket communication passage 19 is dedicated to the inter-cylinder communication hole 12, and the inter-cylinder communication hole Since a strong negative pressure can be applied to 12, the flow rate of the cooling water in the inter-cylinder communication hole 12 can be further increased.

  If the inter-jacket communication passage 19 and the interlayer communication passage 20 are provided in addition to the recessed portion 11 of the block jacket 5, the cooling water is evenly distributed to the lower layer portion 16 of the head jacket 18 and the inter-jacket communication passage 19. This is preferable. The head jacket can be formed of three or more layers. In this case, the interlayer communication path connecting at least the two lower layers and the communication path between the jackets are directly above the vicinity of the outlet of the inter-cylinder communication hole ( It may be arranged at substantially right above).

  Of the bottom surface of the lower layer portion 16 in the head jacket 18, a cylindrical portion protruding toward the upper layer portion 17 can be provided at the opening edge of the inter-jacket communication passage 19 communicating with the inter-cylinder communication hole 12. In this case, since the strong negative pressure can be applied to the inter-jacket communication passage 19 by the flow of the interlayer communication passage 20, it can be said that the flow of the inter-cylinder communication hole 12 can be further accelerated.

  The present invention can be embodied in an internal combustion engine. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Cylinder block 2, 3, 4 Cylinder 5 Block jacket 7, 8 Jacket groove 10 Inter-cylinder part 11 Recessed part 12 Inter-cylinder communication hole 13 Inlet of inter-cylinder communication hole 14 Outlet of inter-cylinder communication hole 15 Cylinder head 16 Head jacket Lower layer part 17 Upper layer part of head jacket 18 Head jacket 19 Communication path between jackets 20 Interlayer communication path

Claims (1)

A cylinder block having a plurality of cylinders, and a cylinder head fixed to the upper surface of the cylinder block;
The cylinder block is formed with a block jacket surrounding the cylinder row opened upward, and an inter-cylinder communication hole that connects block jackets located on both sides of the cylinder row in the portion between the cylinder rows The inter-cylinder communication hole has one end serving as an inlet for cooling water and the other end serving as an outlet for cooling water.
The cylinder head is formed in a state where the head jacket is divided into a plurality of upper and lower layers, the lowermost layer and the block jacket are connected by an inter-jacket communication path, and the layers adjacent to the upper and lower are connected by an interlayer communication path. The configuration
The inter-jacket communication passage and the interlayer communication passage are disposed substantially directly above the vicinity of the outlet of the inter-cylinder communication hole.
Multi-cylinder internal combustion engine.

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