JP2010007596A - Engine coolant diversion structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently cool a cylinder block 1 and prevent the local cooling of the cylinder block 1 by devising a method of introducing a coolant to a coolant jacket 3 from a coolant introduction passage 4. <P>SOLUTION: This structure is provided with the coolant jacket 3 provided in the cylinder block 1 to go around a cylinder row by left-side and right-side channels 31, 32 and front-side and back-side communication paths 33, 34, and the coolant introduction passage 4 introducing the coolant to the coolant jacket 3. A boss 6 including a diversion control wall 61 disposed oppositely to a communication port and diverting the coolant is provided near the communication port of the coolant introduction passage 4 integrally with a front end wall 11 of the cylinder block 1. A position of a tip of the diversion control wall 61 in a fore-and-aft direction is set to project a position the same as a rear partition wall 42 of the coolant introduction passage 4 or in the rear of the rear partition wall 42. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention provides a cylinder with high cooling efficiency by appropriately diverting the coolant when the coolant is introduced from the outside to the coolant jacket provided so as to go around the cylinder row in the cylinder block of the engine. The present invention relates to a structure for cooling a block.

  Conventionally, for example, in Patent Document 1, as a cooling structure of a cylinder block including a four-cylinder siamese cylinder arranged in series in the front-rear direction, a left side and a right side extending in the front-rear direction on both the left and right sides of the cylinder row are disclosed. The coolant is circulated around the cylinder row by the flow path and the front and rear communication paths extending substantially in the left-right direction so that the front end and the rear end of the left and right flow paths communicate with each other. A structure of a cylinder block provided with a jacket is known. In this cylinder block, a coolant introduction passage for introducing coolant into the coolant jacket is formed inside the left side wall, and a volute chamber for a coolant circulation pump is provided on the left side of the cylinder block. An opening is formed in the wall. The upstream end of the coolant introduction path is connected to the volute chamber, while the downstream end of the coolant introduction path is in communication with the vicinity of the connection portion between the left flow path and the front communication path in the coolant jacket. ing.

Then, the circulation pump attached to the left side wall of the cylinder block is driven to rotate by the crankshaft of the engine via a V-ribbed belt or the like, so that the impeller in the volute chamber rotates to cool the volute chamber. The coolant is introduced into the coolant jacket from the outside through the fluid introduction path. A part of the coolant introduced into the coolant jacket in this way flows backward through the left channel, reaches the right channel through the rear communication channel, and then the front communication channel. To flow into. Thus, the coolant is led out to the coolant jacket of the cylinder head through the gasket lead-out hole formed at the position of the front communication path. Thus, the basic flow of the coolant in the cylinder block is set to flow to the cylinder head side after flowing around the cylinder row.
JP 2004-286000 A

  By the way, in the cylinder block described in the patent document, the coolant introduction path is formed to extend in the left-right direction in the left side wall of the cylinder block, and cooling introduced from the coolant introduction path to the coolant jacket. The liquid flow is strongly directed in the left-right direction.

  On the other hand, the communication port of the coolant introduction path with respect to the coolant jacket is set in the vicinity of the connecting portion between the left flow path extending in the front-rear direction and the front communication path extending in the left-right direction. The directed coolant is easy to flow to the front communication path extending in the left-right direction. In addition, the left communication path extending in the front-rear direction has a relatively large flow resistance because it circulates around the cylinder row and the flow path length becomes long. Due to these factors, in the cylinder block described in the above-mentioned patent document, most of the coolant introduced through the coolant introduction passage flows to the front communication passage side, and the cylinder head passes through the front communication passage. The coolant will flow into the coolant jacket. As a result, there is a problem that the amount of the coolant circulating around the cylinder row in the cylinder block is reduced and the cooling efficiency of the cylinder block is lowered.

  Further, in the cylinder block described in the patent document, since the communication port of the coolant introduction path is opposed to the bore wall of the cylinder located at the frontmost side, the coolant that has flowed into the coolant jacket from the communication port Comes into direct contact with the bore wall of the cylinder. As a result, the bore wall of the cylinder is locally cooled, resulting in a problem of thermal distortion of the cylinder block.

  The present invention has been made in view of the above points, and the object of the present invention is to sufficiently cool the cylinder block by devising a way of introducing the coolant from the coolant introduction path to the coolant jacket. It is also possible to prevent the local cooling in the cylinder block.

  In view of the above problems, the inventor of the present application arranges the flow dividing control wall so as to face the communication port of the coolant introduction path with respect to the coolant jacket, and thereby flows in the coolant jacket in the left-right direction. As a result of repeated studies focusing on directing the coolant backward, the coolant flowing on the flow path side extending in the front-rear direction and the left-right direction are adjusted by adjusting the positional relationship between the flow control wall and the communication port. The present invention has been completed by finding that the flow rate ratio with respect to the coolant flowing in the front communication passage extending to the front can be adjusted.

  According to one aspect of the present invention, the engine coolant diversion structure includes a cylinder block having a cylinder row in which a plurality of cylinders are arranged in series in the front-rear direction, and one side and the other side in the left-right direction across the cylinder row The front and rear sides extending substantially in the left-right direction so that the one-side and other-side flow paths extending in the front-rear direction and the front end portion and the rear end portion of the one-side and other-side flow paths communicate with each other. And a coolant compartment provided in the cylinder block so as to circulate around the cylinder row, and a front section facing in the front-rear direction at a front end portion on one side wall in the left-right direction of the cylinder block. It is divided by the wall and the rear partition wall so as to extend in the left-right direction, and its downstream end is in the vicinity of the connection portion between the flow path on the one side and the communication path on the front side. By communicating with the serial coolant jacket comprises a coolant introduction path for introducing the cooling fluid from the outside to the coolant jacket, the.

  The front communication path in the cooling liquid jacket is a cooling liquid lead-out section that leads the cooling liquid toward a cooling liquid jacket of a cylinder head attached to the upper side of the cylinder block. A boss portion of a head bolt hole into which a head bolt for fastening the cylinder head to the cylinder block is inserted protrudes rearward from the front end wall of the cylinder block in the vicinity of the communication port for the coolant jacket. The boss portion extends rearward from the front end wall of the cylinder block so as to face the communication port, and the coolant introduction path The coolant flowing in the cooling liquid jacket is directed to the left and right by flowing along the Therefore, it has a flow dividing control wall for diverting the coolant in both the one-side flow path and the front communication path, and the position of the tip of the flow dividing control wall in the front-rear direction is the position of the coolant introduction path. It is set to protrude rearward from the same position as the rear partition wall or the rear partition wall.

  According to this configuration, a diversion control wall provided at the boss portion of the head bolt hole is arranged in the vicinity of the communication port with respect to the coolant jacket of the coolant introduction path so as to face the communication port. As a result, the coolant flowing from the coolant introduction path into the coolant jacket with a strong directivity in the left-right direction changes its flow direction toward the rear by striking the shunt control wall. This makes it easier for the coolant to flow to the side of the one side channel extending in the front-rear direction.

  Here, when the position of the front end of the branch flow control wall with respect to the front-rear direction is set to the same position as the rear partition wall of the coolant introduction path, the coolant that flows in the flow path on one side extending in the front-rear direction and the left-right direction extend. When the flow rate ratio with respect to the coolant flowing to the front communication passage is approximately 50:50 and the position of the tip of the flow dividing control wall is set to protrude rearward from the rear partition wall, The flow rate ratio of the coolant flowing to the road side becomes relatively high.

  Then, by setting the flow rate ratio of the coolant flowing to the one flow path side to 50% or more, a sufficient amount of coolant flows in the cylinder block, and the cylinder block is sufficiently cooled. .

  In addition, since the shunt control wall is disposed relative to the communication port, as described above, the coolant flowing into the coolant jacket from the coolant introduction path comes into contact with the shunt control wall. It is avoided that the liquid hits the cylinder bore wall directly. Thereby, local cooling in the cylinder block is prevented.

  Further, since the diversion control wall is formed by a boss portion of a head bolt hole provided so as to protrude rearward from the front end wall of the cylinder block, the diversion control wall is not increased in length in the front-rear direction of the engine. A control wall can be provided, and the boss portion is provided integrally with the front end wall of the cylinder block, so that sufficient rigidity is ensured, which is advantageous from the viewpoint of engine reliability.

  The coolant that has flowed from the coolant introduction path to the flow path on one side flows from the rear communication path to the front communication path via the other flow path. And it is sufficient.

  By doing so, a sufficient amount of coolant flows in the cylinder block so as to go around the cylinder row, and the cooling efficiency of the cylinder block is increased.

  A second head bolt hole through which another head bolt is inserted is formed at a position opposite to the first head bolt hole disposed in the vicinity of the communication port of the coolant introduction path. The straight line connecting the first head bolt hole and the second head bolt hole in the left-right direction passes through the vicinity of the front end of the most front cylinder, and the position of the boss portion in the front-rear direction is It is good also as setting to the position which overlaps with the front division wall of the said coolant introduction path.

  By doing so, the position of the boss portion is optimized, and accordingly, the relative position of the flow dividing control wall with respect to the communication port of the coolant introduction path is also optimized. As a result, it is possible to accurately set the flow rate ratio between the coolant flowing on the one flow path side and the coolant flowing on the front communication path side to a desired ratio.

  The diversion control wall of the boss portion may be provided so as to extend in the vertical direction over at least the entire range in the depth direction of the coolant introduction path.

  By doing so, the coolant flowing into the coolant jacket from the coolant introduction path can be reliably directed rearward by the shunt control wall. As a result, it is possible to accurately set the flow rate ratio between the coolant flowing on the one flow path side and the coolant flowing on the front communication path side to a desired ratio. Further, since the boss portion is formed to extend in the up-down direction, an effect that the rigidity of the boss portion is increased is also obtained.

  The upstream end of the coolant introduction path is open toward the outer side in the left-right direction on one side surface of the cylinder block, and the upstream opening of the coolant introduction path is also formed on one side surface of the cylinder block. A mounting seat may be formed so as to surround the mounting seat, and a coolant circulation pump may be attached to the mounting seat.

  That is, while the upstream end of the coolant introduction path is opened on one side surface of the cylinder block, it is driven by the engine crankshaft by not forming a volute chamber on the side surface of the cylinder block, unlike the conventional cylinder block. Both the mechanical circulation pump and the electric circulation pump can be attached to one side surface of the cylinder block. This has a great advantage that the cylinder block can be shared even if the type of the circulation pump is different.

  As described above, according to the present invention, the branch flow control wall of the boss portion is disposed so as to face the communication port of the coolant introduction path with respect to the coolant jacket, and the tip position of the flow control wall is adjusted. Accordingly, it is possible to appropriately set the flow rate ratio between the coolant flowing on the side of the one flow path extending in the front-rear direction and the coolant flowing on the front communication path extending in the left-right direction. As a result, the cylinder block can be reliably cooled by flowing a sufficient amount of the cooling liquid to the one flow path side. In addition, since the coolant flowing into the coolant jacket is prevented from directly hitting the bore wall of the cylinder, local cooling in the cylinder block can be prevented.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

  1 and 2 show a cylinder block 1 to which an engine coolant splitting structure according to an embodiment of the present invention is applied. This engine is an in-line four-cylinder gasoline engine provided with four cylinders S1 to S4 arranged linearly in the direction in which the crankshaft extends, although the entire illustration is omitted.

  In this engine, an aluminum alloy cylinder head (not shown) is assembled on the upper side of the aluminum alloy cylinder block 1 to form an engine body. The engine is further formed on the upper surface of the cylinder head. While a cylinder head cover (not shown) is assembled, an oil pan (not shown) is also assembled to the lower surface of the cylinder block 1.

  In addition, this engine is mounted horizontally in the engine room of the vehicle so that the direction of the cylinder row in which the four cylinders are arranged, that is, the direction in which the crankshaft extends approximately matches the width direction of the vehicle (not shown). is there. In this specification, the longitudinal direction of the cylinder block 1, that is, the direction in which the crankshaft extends is the longitudinal direction of the engine (cylinder block 1), and the output end side of the crankshaft (the left side in FIGS. While called the rear side, the opposite side (right side in FIGS. 1 and 2) is called the front side of the engine. When the engine (cylinder block 1) is viewed from the rear side to the front side, the right side is called the right side (lower side in FIG. 1) of the engine (cylinder block 1), and the opposite side is called the left side of the engine (cylinder block 1) ( The upper side in FIG.

  The cylinder block 1 includes a front end wall 11, a rear end wall 12, a left side wall 13 and a right side wall 14. As shown in FIGS. 1 and 3, the cylinder block 1 has a rear end from the first cylinder S 1 on the engine front end side. Up to the fourth cylinder S4 on the side, four cylinders are formed. The four cylinders S1 to S4 are siamese cylinders in which adjacent cylinders are connected to each other, and cast cylinders 21, 21,... (Shown only in FIG. 3) are cast on each cylinder S1, S2,. It is wrapped up.

  As shown in FIG. 1, the top deck 15 of the cylinder block 1 is formed with a total of 10 head bolt holes 22, 22,... For attaching a cylinder head to the cylinder block 1. Are arranged at four locations so as to surround the cylinders S1, S2,... At equal intervals in plan view (as viewed along the axis of the cylinders S1, S2,...). Yes.

  The cylinder block 1 is provided with a coolant jacket 3 so as to go around the four cylinders S1 to S4 as shown in FIGS. Specifically, as shown in FIG. 3, the coolant jacket 3 is formed on the left and right side walls 13 and 14 of the cylinder block 1 so as to be curved along the outer shapes of the cylinders S1 to S4, respectively. The left channel 31 and the right channel 32, and the left channel 31 and the right channel 32, which extend in the front-rear direction from the engine front end to the rear end, are connected to the cylinder block 1. The front side communication path 33 and the rear side communication path 34 are respectively configured to communicate with each other at both front and rear ends. In addition, although illustration is abbreviate | omitted, between the cylinders, the cross drill which connects the left flow path 31 and the right flow path 32 mutually is provided. The coolant jacket 3 is formed to a depth corresponding to about the upper half of the cylinder block 1 as shown in FIG.

  The top deck 15 of the cylinder block 1 has an odd-shaped hole that passes through the top deck 15 so as to follow the shape of the coolant jacket 3 and allows the coolant to flow from the coolant jacket 3 to the coolant jacket of the cylinder head. .. Are provided, and the cylinder block 1 is a so-called closed deck type. Here, as shown in FIG. 3, the front communication passage 33 is formed to extend forward so as to be substantially rectangular in a plan view on the front side of the first cylinder S <b> 1. The cooling liquid lead-out part mainly leads out the cooling liquid toward the cooling liquid jacket of the cylinder head. That is, each hole shown with a dashed-dotted line in FIG. 3 has shown the extraction holes 36 and 37 formed in the gasket (illustration omitted) interposed between the cylinder block 1 and the cylinder head. Thus, the coolant flows from the cylinder block 1 to the cylinder head. The lead-out hole 37 is a hole with a small area that allows the coolant to leak, and the main function is to vent the air.

  As shown in FIGS. 1 to 3, a coolant introduction passage 4 for introducing coolant into the coolant jacket 3 is formed through the upper end of the front end side of the right side wall 14 of the cylinder block 1. Yes.

  As shown in FIGS. 2 and 3, the coolant introduction path 4 includes a front partition wall 41 and a rear partition wall 42 that face each other in the front-rear direction, and is formed in a substantially rectangular shape in cross section. The right side wall 14 is extended in the left-right direction. Thus, the upstream end of the coolant introduction path 4 opens sideways in the right side wall 14 of the cylinder block 1, while its downstream end is connected to the right flow path 32 in the coolant jacket 3. In the vicinity of the connecting portion with the front communication path 33, the communication path 43 communicates.

  The connecting path 43 is disposed to extend in an oblique direction from the opening at the downstream end of the coolant introduction path 4 toward the rear inward of the cylinder block 1, so that the connecting path 43 is as described above. In addition, the downstream end of the coolant introduction path 4 is connected to the vicinity of the connection portion between the right side flow path 32 and the front communication path 33.

  Here, as shown in FIGS. 4 and 5, the coolant introduction path 4 is set to have a shallower depth in the vertical direction than the coolant jacket 3, and the coolant introduction path 4. And the coolant path 3 are set so that the flow path depth increases stepwise from the coolant introduction path 4 side toward the coolant jacket 3 side.

  As shown in FIGS. 1 and 2, four mounting seats 16, 16,... Are provided on the right side wall 14 of the cylinder block 1 so as to surround the opening at the upstream end of the coolant introduction path 4. A coolant circulation pump 5 is attached to the mounting seat 16. The circulation pump 5 is provided in front of the front end wall of the cylinder block 1 and includes a pulley 51 around which a V-ribbed belt (not shown) is wound, and is driven to rotate by a crankshaft of the engine.

  Here, the right side wall 14 of the cylinder block 1 is not integrally formed with a volute chamber in which an impeller of a circulation pump is built, unlike a conventional cylinder block. Therefore, although the detailed illustration is abbreviate | omitted, the circulation pump attached here is a pump which incorporated the impeller and the volute part. Instead of such a mechanical pump, an electric circulation pump can be attached to the right side wall of the cylinder block 1. That is, since the volute chamber is not formed in the right side wall 14 of the cylinder block 1, the cylinder block 1 has an advantage that it can be used as both a mechanical circulation pump and an electric circulation pump.

  Then, by rotating the circulation pump 5 with the crankshaft of the engine, the coolant is introduced from the outside into the coolant jacket 3 via the coolant introduction path 4 and the connection path 43, and one of the coolants is supplied. After flowing in the right flow path 32, the section flows from the rear communication path 34 through the left flow path 31 to the front communication path 33. That is, in the coolant jacket 3 that goes around the cylinder row, the coolant flows in the clockwise direction shown in FIG. A part of the cooling liquid introduced into the cooling liquid jacket 3 through the cooling liquid introduction path 4 also flows in a diverted manner to the front communication path 33. The coolant mainly flows so as to be led out to the coolant jacket of the cylinder head through the lead-out hole 36.

  The most characteristic point in the cylinder block 1 according to the present embodiment is that, among the four head bolt holes 22 arranged so as to surround the first cylinder S1, the front side and the right side with respect to the first cylinder S1. The boss portion 6 of the head bolt hole 221 located at the point of having a flow dividing control wall 61.

  That is, the boss portion 6 is provided integrally with the front end wall 11 so as to protrude rearward from the front end wall 11 of the cylinder block 1, and as shown in FIG. Thru | or extending in the up-down direction over the whole area of the depth direction of the connection path 43, and is arrange | positioned. As described above, the boss portion 6 is provided integrally with the front end wall 11 of the cylinder block 1 and the height thereof is sufficiently extended, so that the rigidity of the boss portion 6 is sufficiently increased and the reliability of the engine is improved. Can be secured.

  Further, as shown in FIG. 6, the center of the head bolt hole 221 formed in the boss portion 6 and the center of the head bolt hole 222 located on the front side and the left side with respect to the first cylinder S1 are connected in the left-right direction. The straight line L is set so as to pass through the vicinity of the front end of the first cylinder S1, and the boss portion 6 is positioned so as to overlap the front partition wall 41 of the coolant introduction path 4 in the front-rear direction. It is arranged.

  Then, the right side surface of the boss portion 6 constitutes a flow dividing control wall 61 that is disposed so as to be opposed to the communication port of the coolant introduction path 4.

  The split flow control wall 61 is disposed so as to extend rearward from the front end wall 11 of the cylinder block 1, whereby the coolant flowing from the coolant introduction path 4 to the connection path 43 to the coolant jacket 3 is separated. By hitting the control wall 61, it has a function of directing the coolant toward the rear of the cylinder block 1 and flowing it through the coolant jacket 3 (see the white arrow in FIG. 6).

  Here, in this embodiment, as shown in FIG. 6 (note that FIG. 6 is drawn with the top and bottom reversed with respect to FIG. 3), the tip of the shunt control wall 61 (the end at the rear of the engine) is The cooling liquid introduction path 4 is disposed so as to protrude rearward from the rear partition wall 42 by a predetermined protrusion amount Δt. By doing so, when the coolant flows from the coolant introduction path 4 through the connection path 43 into the coolant jacket 3, the flow rate of the coolant flowing to the right flow path 32 side and flowing to the rear of the cylinder block 1. The ratio increases relatively with respect to the flow rate ratio of the coolant flowing toward the front communication path 33 and mainly flowing toward the cylinder head.

  This will be described with reference to FIGS. FIG. 7 shows the relationship between the flow rate ratio of the coolant flowing on the right flow path 32 side (black square) and the flow rate ratio of the coolant flowing on the front communication path 33 side (white circle) with respect to the protrusion amount Δt. This relationship is obtained by simulation. Here, the protrusion amount Δt = 0 means that the tip position of the flow dividing control wall 61 and the rear partition wall 42 of the coolant introduction path 4 are in the same position in the front-rear direction, and the protrusion amount Δt is plus (+). The fact is that the tip position of the flow dividing control wall 61 protrudes rearward from the rear partition wall 42 of the coolant introduction path 4, and conversely, the protrusion amount Δt is minus (−). It means that the front end position of the flow dividing control wall 61 is located in front of the rear partition wall 42 of the coolant introduction path 4.

  According to FIG. 7, when the protrusion amount Δt = 0, the ratio of the flow rate of the coolant flowing to the right flow path 32 side and the flow rate of the coolant flowing to the front communication path 33 side is 50:50. When the protrusion amount Δt is negative, the ratio of the flow rate of the coolant flowing toward the front communication path 33 is relatively increased. On the other hand, when the protrusion amount Δt is positive, the cooling flows toward the right channel 32 side. The ratio with the flow rate of the liquid is relatively increased.

  Therefore, as shown in the present embodiment, the front end of the flow dividing control wall 61 is protruded rearward from the rear partition wall 42 of the coolant introduction path 4 so as to flow toward the right flow path 32 and to the rear of the cylinder block 1. The ratio of the flow rate of the flowing coolant can be made higher than the ratio of the flow rate of the coolant that flows to the front communication path 33 and flows mainly to the cylinder head side. As a result, a sufficient amount of coolant can be flown around the cylinder row in the cylinder block 1, and the cylinder block 1 can be appropriately cooled.

  Further, since the coolant flowing to the front communication path 33 side is introduced from there to the cylinder head side, it is combined with the coolant after circling the cylinder row to properly cool the cylinder head. be able to.

  Further, since the ratio of the flow rate of the coolant flowing to the right flow path 32 side is relatively high, the flow direction of the coolant circulating around the cylinder row in the cylinder block 1 is approximately the clockwise direction in FIG. Become. Accordingly, it is possible to avoid the collision of the coolant flow flowing in the clockwise direction in the coolant jacket 3 and the coolant flow flowing in the counterclockwise direction in the middle of the coolant jacket 3, and the cylinder block. The flow of the cooling liquid in 1 becomes smooth.

  As a result, the cooling efficiency of the cylinder block 1 is increased.

  Further, the branch flow control wall 61 prevents the coolant flowing from the coolant introduction path 4 to the coolant jacket 3 from directly hitting the bore wall of the first cylinder S1. This avoids local cooling of the bore wall of the cylinder S1, which is advantageous in terms of thermal distortion of the cylinder block 1.

  The flow rate of the coolant flowing to the right flow path 32 side and flowing behind the cylinder block 1 and the flow rate of the coolant flowing to the front communication path 33 side and mainly flowing to the cylinder head side are: The ratio can be set as appropriate. From the viewpoint of sufficiently cooling the cylinder block 1, it is preferable that the ratio of the flow rate of the coolant flowing to the right flow path 32 side and flowing behind the cylinder block 1 is 50% or more. Therefore, it is preferable that the front end position of the flow dividing control wall 61 is the same position as the rear partition wall 42 of the coolant introduction path 4 or protrudes rearward thereof.

  In the above embodiment, the present invention is applied to the closed deck type cylinder block 1, but the present invention can also be applied to an open deck type cylinder block. The number of cylinders in the cylinder block 1 is not particularly limited.

  As described above, the present invention can appropriately cool the cylinder block, and thus is useful as an engine coolant diversion structure in which a plurality of cylinders are arranged in series.

It is a top view of a cylinder block. It is a right side surface of a cylinder block. FIG. 3 is an end view taken along the line III-III in FIG. 2. It is IV-IV sectional drawing of FIG. It is VV sectional drawing of FIG. It is explanatory drawing which expands and shows the part of the communicating port of a cooling water introduction path. It is a figure which shows the relationship of the shunt rate with respect to the protrusion amount obtained by simulation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder block 11 Front end wall 12 Rear end wall 13 Left side wall 14 Right side wall 16 Mounting seat 22 Head bolt hole 3 Coolant jacket 31 Left flow path 32 Right flow path 33 Front communication path 34 Rear communication path 36 Derivation Hole (cooling liquid outlet)
4 Coolant introduction passage 41 Front partition wall 42 Rear partition wall 5 Circulation pump 6 Boss portion 61 Flow control walls S1 to S4 Cylinder

Claims (5)

A cylinder block having a cylinder row in which a plurality of cylinders are arranged in series in the front-rear direction;
One side and the other side flow path extending in the front-rear direction on each of one side and the other side in the left-right direction across the cylinder row, and each of the front end part and the rear end part of the one side and the other side flow path A cooling fluid jacket provided in the cylinder block so as to circulate around the cylinder row, comprising front and rear communication passages extending substantially in the left-right direction so as to communicate with each other;
At the front end portion of the side wall on one side in the left-right direction of the cylinder block, the cylinder block is partitioned by the front partition wall and the rear partition wall facing each other in the front-rear direction so as to extend in the left-right direction. A coolant introduction path for introducing the coolant into the coolant jacket from the outside by communicating with the coolant jacket in the vicinity of the connection portion between the one-side flow path and the front communication path;
The front communication path in the cooling liquid jacket is a cooling liquid lead-out part that leads the cooling liquid toward a cooling liquid jacket of a cylinder head attached to the upper side of the cylinder block.
A boss portion of a head bolt hole through which a head bolt for fastening the cylinder head to the cylinder block is inserted in the vicinity of the communication port with respect to the coolant jacket of the coolant introduction path. It is provided integrally with the front end wall so as to protrude rearward from the front end wall,
The boss portion extends rearward from the front end wall of the cylinder block so as to face the communication port, and flows along the cooling liquid introduction path so as to be directed in the left-right direction and the cooling. Having a flow control wall for directing the coolant flowing into the liquid jacket to the rear, thereby diverting the coolant to both the one-side flow path and the front communication path;
The position of the front end of the branch flow control wall with respect to the front-rear direction is the same position as the rear partition wall of the coolant introduction passage, or the engine coolant split flow structure set to protrude rearward from the rear partition wall . The engine coolant diversion structure according to claim 1,
The coolant that has flowed from the coolant introduction path to the one-side flow path side passes through the other-side flow path from the rear-side communication path to the front-side communication path. Coolant splitting structure. The engine coolant diversion structure according to claim 1 or 2,
A second head bolt into which another head bolt is inserted at a position opposite to the first head bolt hole disposed in the vicinity of the communication port of the coolant introduction path in the left-right direction across the cylinder. A hole is formed, and a straight line connecting the first head bolt hole and the second head bolt hole in the left-right direction passes through the vicinity of the front end of the cylinder located on the foremost side,
A position of the boss portion with respect to the front-rear direction is an engine coolant diversion structure that is set to a position that overlaps the front partition wall of the coolant introduction path. The engine coolant diversion structure according to any one of claims 1 to 3,
The divergence control wall of the boss portion is an engine coolant splitting structure that extends in the vertical direction over at least the entire range in the depth direction of the coolant introduction path. The engine coolant diversion structure according to any one of claims 1 to 4,
The upstream end of the coolant introduction path is open toward the outside in the left-right direction on one side of the cylinder block,
A mounting seat is also formed on one side surface of the cylinder block so as to surround the upstream opening of the coolant introduction path, and a coolant circulating pump for the coolant is attached to the mounting seat. Shunt structure.

Images