JP4461951B2 - Engine cooling system - Google Patents

Description

  The present invention relates to an engine cooling apparatus.

  Conventionally, as one of the methods of circulating cooling water in a cylinder block and a cylinder head in an engine cooling device, as disclosed in, for example, JP-A-2002-115600, a water jacket provided on the cylinder block side is used. Cooling water is fed from one end of the block and flows in parallel on both the left and right sides of the in-line cylinder, and there are small holes in the water jacket of the cylinder head that lift the cooling water in the middle of the cylinder. After creating the flow, the cooling water after passing through the block on the other end side of the block is lifted to the cylinder head and flowed in parallel on both the left and right sides of the in-line cylinder in the same manner as the cylinder block. A system is known in which cooling water that has passed through a block is taken out and sent to a radiator. However, in this method, on the cylinder block side, cooling water stagnation tends to occur in the lower part of the water jacket where the cooling water is moved to the cylinder head, and on the cylinder head side, on the one end side water jacket upper part of the head, Cooling water stagnation tends to occur, and there is a problem that the temperature distribution becomes non-uniform. This problem causes a decrease in combustion efficiency in the cylinder, that is, a decrease in fuel consumption performance.

  As a method for solving this, conventionally, as disclosed in, for example, Japanese Patent Laid-Open No. 7-224651, cooling water is fed from one end side of the block, and first flows to the left and right sides of the in-line cylinder on the cylinder block side. There is known a method (so-called U-turn method) in which a U-turn is made on the end side and the U-turn is made to flow on the opposite side of the in-line cylinder. In this U-turn system, the cooling water flows in one direction through the passage formed in the block, so that the cooling water is unlikely to stagnate, and good temperature distribution uniformity can be realized.

JP 2002-115600 A JP-A-7-224651

  By the way, in order to realize better engine cooling performance, it is necessary to consider the temperature distribution depending on the structure and arrangement of various configurations of the engine in configuring the cooling passage in the cooling device. In the engine, it is known that the temperature of the cylinder head on the side where the exhaust system is provided is high. In the cooling device that circulates the cooling water in the first place, the cooling water is first made to flow from the intake side to the exhaust side on the cylinder block side by the U-turn method, and then moved to the cylinder head side, and from the exhaust side to the intake side. The cooling water is made to flow in a U-turn system. That is, in order to preferentially cool the exhaust side on the cylinder head side, the cooling water flows first to the intake side on the cylinder block side. In particular, in an open deck type cylinder block in which the water jacket of the cylinder block is opened upward, when the U-turn method is used, cooling water is unlikely to stagnate, and the cylinder block is thermally against the cylinder head. However, there is little effect when cooling water flows from either the exhaust side or the intake side of the cylinder block, or from the thrust side or the anti-thrust side, but the cylinder block has a deck section above the water jacket. In the closed deck type cylinder block provided, there is a risk that cooling water air may accumulate in the vent holes for casting or stagnation of the cooling water during casting, so heat transfer from the cylinder head is particularly large. At the top of the cylinder block, when cooling by the U-turn method, the exhaust side Does the cooling water flows from either side of the intake side and, if the cooling water flows from either side of the thrust side or anti-thrust side becomes an important issue.

In the above-described aspect, it is only considered to ensure the cooling performance on the exhaust side of the cylinder head. However, although the influence is less than that on the cylinder head side, the exhaust side is actually also on the cylinder block side. Since the temperature is higher than that on the intake side, a temperature difference occurs between the two. Therefore, in order to ensure better engine cooling performance, it is desirable to preferentially flow cooling water to the exhaust side in both the cylinder block and the cylinder head.
In order to achieve better engine cooling performance, it is necessary to consider the effects other than those on the exhaust side and the intake side. For example, in an engine, the thrust side and the anti-thrust side of a cylinder are determined according to the rotation direction of the crankshaft, but particularly on the thrust side, the frictional heat generated between the piston and the cylinder inner wall is large, and the thrust side and the anti-thrust side There will be a temperature difference between them. Therefore, it is desirable to configure the cooling water passage in the cooling device while taking this factor into consideration.

  The present invention has been made in view of the above technical problem, and considers the structure and arrangement of various configurations of the engine while improving the uniformity of the temperature distribution in the engine and realizing better engine cooling performance. An object of the present invention is to provide a cooling device.

Therefore, the invention according to claim 1 of the present application is a cooling device that cools a cross-flow type in-line multi-cylinder engine in which an intake system and an exhaust system are arranged on opposite sides of a cylinder head. A passage communicating with a cooling water inflow port provided in the vicinity thereof, extending along the thrust side surface of the in-line multi-cylinder, and further extending along the anti-thrust side surface via the other end side of the cylinder block. A block cooling passage partitioned on one end side of the cylinder block, and one end side of the cylinder head communicating with the block cooling passage on one end side and thrust side of the cylinder block at a position upstream of the block cooling passage. At one end side of the cylinder block and at the side opposite to the thrust side at a position downstream of the first cooling passage and the block cooling passage. A second communication path that communicates with the cooling path and reaches one end of the cylinder head, and a cylinder head that is provided with a cooling water outflow port from one end of the cylinder head that communicates with the first and second communication paths. A head cooling passage extending to the end side , and in the longitudinal direction of the cylinder head, the cooling water sent through the first communication passage is caused to flow to the exhaust side in the cylinder head. is obtained by the features that you have vertical ribs of a predetermined height is formed extending along the.

  Further, the invention according to claim 2 of the present application is the invention according to claim 1, wherein the in-line multi-cylinders are horizontally mounted so as to be arranged along the vehicle width direction, and the thrust is disposed behind the main body in the vehicle longitudinal direction. A cooling device provided in an engine having a so-called rear exhaust layout in which an exhaust system is arranged corresponding to the side, a radiator is disposed in front of the engine body, and a front side surface of the engine body on one end side of the cylinder block A water pump is provided at the one end side of the cylinder block as a part of the block cooling passage, and the cooling water cooled by the radiator is supplied from the front of the engine body to the thrust side of the block cooling passage. It is characterized in that a passage is formed.

  Further, the invention according to claim 3 of the present application is the invention according to claim 2, wherein a plurality of communication passages including the first and second communication passages and communicating with the block cooling passage and the head cooling passage are provided. The opening area of the communication path provided on one end side of the cylinder block and in the vicinity thereof is set to be relatively large.

Furthermore, the invention according to claim 4 of the present application is the closed deck type block according to any one of the inventions according to claims 1 to 3 , wherein the cylinder block includes a deck portion on an upper portion of the water jacket, In the deck portion, a plurality of vent holes are formed corresponding to the block cooling passages.

According to the invention of claim 1 of the present application, in the block cooling passage, the cooling water is first sent to the thrust side, so that the cooling performance on the relatively high temperature thrust side can be improved, and the cooling water By being sent around the cylinder in one direction, the stagnation of the cooling water can be suppressed and the temperature uniformity of each cylinder can be improved. This also suppresses the deformation of the in-line cylinders, and improves the fuel efficiency by increasing the uniformity of intake charging by the intake system. Further, in the head cooling passage, a relatively low temperature cooling water sent through the first communication passage is secured on one end side of the cylinder head, so that the cooling performance on the cylinder head side is improved. Can do. Furthermore, since the exhaust side is cooled by relatively low-temperature cooling water, the temperature difference between the exhaust side and the intake side in the cylinder head can be suppressed, and the uniformity of the engine temperature distribution can be improved.

  Further, according to the invention according to claim 2 of the present application, the so-called rear exhaust engine cannot be expected to be cooled by traveling wind, and can improve the engine cooling performance on the exhaust side where the temperature becomes high. Moreover, various piping which makes a cooling passage outside a block cooling passage and an engine main body can be simplified.

  Further, according to the invention of claim 3 of the present application, the opening area of the communication path provided at one end side of the cylinder block and in the vicinity thereof is set to be relatively large. A large amount of cooling water is moved to the cylinder head side, and the cooling performance on the cylinder head side, which is higher than the block side, can be improved.

Furthermore, according to the invention according to claim 4 of the present application, since the cylinder block having the deck portion at the upper part is adopted, the rigidity of the block itself is secured, the deformation of the cylinder is suppressed, and the knocking is performed. While taking advantage of the closed type cylinder block that can ensure the detection performance of knock vibration by the sensor, even if the hole for venting in casting is provided in the deck part, It is possible to improve the cooling performance of the engine by suppressing air accumulation and cooling water stagnation.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing an engine according to Embodiment 1 of the present invention. The engine 1 is an in-line four-cylinder engine in which four cylinders 2A to 2D (see FIG. 2) are provided in series along the longitudinal direction of a crankshaft (not shown). In this engine 1, an engine body 4 is configured by a cylinder block 10 made of aluminum alloy and a cylinder head 20 made of aluminum alloy that is assembled on the upper side of the cylinder block 10. A cylinder head cover 40 is disposed on the side.

In the present embodiment, the engine 1 is horizontally mounted in an engine room (not shown) provided at the front of the vehicle so that the crankshaft extends along the vehicle width direction. With the engine 1 mounted in this manner, the right front side of the page in FIG. 1 corresponds to the front side of the engine 1 in the vehicle front-rear direction, and the left back side of the page corresponds to the rear side of the engine 1. In such a state, the transmission 70 is disposed on the left side of the engine main body 4 (the right rear side in FIG. 1).
The “front side” used below represents the front side in the vehicle front-rear direction, and the “rear side” represents the rear side in the vehicle front-rear direction.

  Further, an intake manifold 50 for introducing intake air into each of the cylinders 2A to 2D (see FIG. 2) is disposed on the front side of the engine body 4. The intake manifold 50 includes four branch pipes, and each branch pipe communicates with each cylinder 2 </ b> A to 2 </ b> D configured in the engine body 4. On the other hand, an exhaust system (exhaust manifold or the like) is disposed on the rear side of the engine body 4.

  Inside the engine body 4, water jackets 5 and 25 (see FIGS. 2 and 5) forming cooling passages in the cylinder block 10 and the cylinder head 20 are formed. A discharge port of a water pump 52 for circulating the cooling water is connected to a cooling water inflow port 9 (see FIG. 3) serving as an inlet of the cooling water to the water jackets 5 and 25. The water pump 52 is a spiral centrifugal pump, and as shown in FIG. 1, is disposed on one end side (right end side) and the front side of the cylinder block 10, and on one end surface (right end surface) of the cylinder block 10. The crank pulley 53 provided is driven and connected by a V-belt (not shown). Thereby, the water pump 52 is driven by the crankshaft.

  Further, a thermostat housing 54 that is disposed between the intake manifold 50 and the water pump 52 and communicates with the suction port of the water pump 52 is provided on the front side of the cylinder block 10. The thermostat housing 54 has a radiator bypass inflow port 54a opened on the upper surface thereof, and also has a heater inflow port 54b and a radiator inflow port 54c provided on the side surface thereof. A radiator bypass pipe 56 constituting a radiator bypass path is connected to the radiator bypass inflow port 54a. In addition, a heater return pipe 57 that constitutes a heater return path is connected to the heater inflow port 54 b between the heater for indoor heating (not shown) and the thermostat housing 54. Further, a radiator return pipe 58 that forms a radiator return path between a radiator (not shown) and the thermostat housing 54 is connected to the radiator inflow port 54c.

  On the left side of the engine body 4 (strictly speaking, the cylinder head 20), a water outlet member 64 is provided on the cooling water outflow side of the water jackets 5 and 25 formed inside the engine body 4. Are attached so as to communicate with the water jackets 5 and 25. The water outlet member 64 has three outflow ports, namely, a heater outflow port, a radiator outflow port, and a bypass outflow port. A heater pipe 66 that constitutes a heater path is connected to the heater outflow port between the heater and the water outlet member 64. Further, a radiator pipe 67 constituting a radiator path is connected between the radiator and the water outlet member 64 at the radiator outlet port, and a radiator bypass path 68 is connected to the bypass outlet port.

Next, the water jacket 5 of the cylinder block 10 will be described in detail. FIG. 2 is a cross-sectional explanatory view showing the configuration of the water jacket 5 of the cylinder block 10. In this embodiment, also, a series cylinders 2A, 2B, the crank shaft is supported parallel to relative 2C and 2D of the series direction, aft side and intake-exhaust system of the engine main body 4 which exhaust system is provided with The front side of the provided engine main body 4 is rotated so that it is on the thrust side and the anti-thrust side, respectively. In FIG. 2, the center line of the in-line cylinders 2 </ b> A to 2 </ b> D is shown with a symbol C. The upper side of the center line C corresponds to the thrust side, and the lower side of the center line C corresponds to the anti-thrust side. .

In the cylinder block 10, a U-turn type water jacket 5 is formed around the cylinders 2A to 2D. The water jacket 5 is provided on one end side (the left end side in FIG. 2) of the cylinder block 10 on the passage 5a from the cooling water inflow port 9 provided on the anti-thrust side to the thrust side, and on the thrust side wall of the cylinders 2A to 2D. And a passage 5c extending from the thrust side to the anti-thrust side on the other end side (right side in FIG. 2) of the cylinder block 10 and a passage 5d along the anti-thrust side wall of the cylinders 2A to 2D. Is done. The passage 5d and the passage 5a are partitioned by a partition wall 8. A female screw hole 7 for fastening a bolt for attaching the cylinder head 20 to the cylinder block 10 is formed in the partition wall 8. Further, the peripheral edge of the cylinder block 10 includes a female screw hole 7 formed in the partition wall 8, and a plurality of female screw holes 7 are formed.

FIG. 3 is a plan view of the cylinder block 10. The cylinder block 10 is a closed deck type block having a top deck 12 at an upper portion thereof. The top deck 12 covers the water jacket 5 shown in FIG. 2 and forms the upper wall of the water jacket 5 formed on the cylinder block 10 side while forming the opening surfaces of the cylinders 2A to 2D and the female screw hole 7. The top deck 12 includes a water jacket 5 on the cylinder block 10 side and a water jacket 25 (see FIG. 4) on the cylinder head 20 side corresponding to each of the passages 5a to 5d constituting the water jacket 5. A communication path for communication is formed. More specifically, at the upstream position of the water jacket 5, a communication passage 13A disposed on the opposite side to the thrust side and a communication passage 13B disposed on the thrust side are formed corresponding to the passage 5a. Corresponding to 5b, a communication path 13C is formed. Further, a communication path 13D is formed at a position downstream of the water jacket 5 corresponding to the path 5d. The communication passages 13A to 13D are both formed near one end side (the left end side in FIG. 3) of the cylinder block 10, and have different shapes and opening areas according to symbols. In the form shown in FIG. 3, between the opening areas S1 to S4 of these communication passages 13A to 13D,
S2>S1>S4> S3
There is a large and small relationship.

  Further, in addition to the communication passages 13A to 13D, the top deck 12 corresponds to each of the passages 5b, 5c and 5d, and gas for preventing gas accumulation during casting communicated with the water jacket 25 on the cylinder head 20 side. A punch hole 18 is formed. This vent hole 18 serves as a cooling water passage from the water jacket 5 on the cylinder block 10 side to the water jacket 25 on the cylinder head 20 side, and also serves to prevent air accumulation in the cooling water. In practice, a hole corresponding to the hole 18 is formed in the head gasket. However, in the drawing, the gasket is omitted for simplicity. By providing such a gas vent hole 18, air accumulation in the water jacket 5 on the cylinder block 10 side is suppressed, and good circulation of cooling water can be realized. The opening area of the gas vent hole 18 is set smaller than the opening areas S1 to S4 of the communication passages 13A to 13D described above.

  As described above, the cooling water cooled by the radiator (not shown) is fed into the U-turn type water jacket 5 configured in the cylinder block 10 from the cooling water inflow port 9 provided on the anti-thrust side. However, in this case, part of the cooling water is moved to the water jacket 25 on the cylinder head 20 side via the communication paths 13A to 13C immediately after flowing into the water jacket 5. Then, after the remaining cooling water sequentially passes through the passages 5a to 5d in the route indicated by the two-dot chain line arrow in FIG. 2 and returns to one end side of the cylinder block 10, via the communication passage 13D, It is moved to the water jacket 25 on the cylinder head 20 side. In the present embodiment, the cooling water moved to the cylinder head 20 side via the communication paths 13A to 13C has a flow rate substantially equal to or higher than the cooling water moved to the cylinder 20 side via the communication path 13D. The opening area of each communicating path 13A-13D is set so that it may become.

  By configuring the water jacket 5 on the cylinder block 10 side, the cooling water flowing in from the cooling water inflow port 9 first generates frictional heat between the piston and the inner walls of the cylinders 2A to 2D during engine operation. As a result, the engine body is sent to the high temperature thrust side, and the thrust side is preferentially cooled, so that the engine body can be efficiently cooled. Further, immediately after flowing into the water jacket 5, a relatively large flow of cooling water is moved to the cylinder head 20 side through the communication passages 13 </ b> A to 13 </ b> C provided at the upstream position of the water jacket 5. A relatively low-temperature cooling water can be secured by the water jacket 25 on the 20 side.

  Next, the water jacket 25 configured on the cylinder head 20 side will be described. As described above, on the cylinder block 10 side, the U-turn type water jacket 5 in which the cooling water is sequentially circulated on the thrust side and the anti-thrust side is configured. On the other hand, on the cylinder head 20 side, The parallel-type water jacket 25 is configured, and the cooling water that has moved from the cylinder block 10 is circulated from the one end side to the other end side of the cylinder head 20 separately for the thrust side and the anti-thrust side. 4 and 5 are a plan view and a cross-sectional explanatory view of the cylinder head 20 mounted on the top deck 12 of the cylinder block 10, respectively. In FIG. 4, in order to clarify the positional relationship with the cylinder block 10, the center axis C of the in-line cylinders 2 </ b> A to 2 </ b> D represented in FIGS. 2 and 3 is attached. That is, in FIG. 4, as in FIGS. 2 and 3, the upper side of the center line C corresponds to the thrust side, and the lower side of the center line C corresponds to the anti-thrust side.

  The cylinder head 20 has a plurality of exhaust valve holes 31 communicated with exhaust ports (not shown) of the respective cylinders 2A to 2D and a plurality of intake valves communicated with intake ports (not shown) of the respective cylinders 2A to 2D. And a hole 32. Further, the cylinder head 20 is formed with an insertion hole 34 which opens corresponding to the female screw hole 7 provided in the cylinder block 10 and allows a bolt (not shown) to pass therethrough. In addition to this configuration, the cylinder head 20 has a conventionally known configuration, but description of the other configuration is omitted here.

  In the present embodiment, a vertical rib 26 having a predetermined height extending along the longitudinal direction of the cylinder head 20 is further formed at a portion where the water jacket 25 in the cylinder head 20 is formed. The longitudinal ribs 26 extend over the entire length of the water jacket 25, whereby the water jacket 25 is partitioned so as to form passages 25 a and 25 b that run along the longitudinal direction of the cylinder head 20 on the thrust side and the anti-thrust side. Is done. The height of the vertical ribs 26 is normally set so that the cooling water flowing into the passages 25a and 25b is prevented from moving between the passages 25a and 25b in a normal engine operating state. The vertical rib 26 completely separates the exhaust side and the intake side in order to prevent air accumulation in the water jacket 25, for example, when the engine 1 is slanted and mounted in the engine room. It is provided so that there is no. In particular, when the engine 1 is mounted in a slant and the exhaust system is disposed on the rear side, there is a high possibility that the performance of the cooling device is greatly deteriorated due to air accumulation, and the configuration of the vertical rib 26 is effective. .

On one end side (the left end side in FIG. 4) of the cylinder head 20, the thrust side passage 25a communicates with the communication passages 13B and 13C formed on the cylinder block 10 side, while the anti-thrust side passage 25b It communicates with communication passages 13A and 13D formed on the block 10 side. Cooling water has flowed through the communication passage 13B and 13C from the water jacket 5 of the cylinder block 10 side, and the cooling water that has flowed through the communication passage 13 A and 13 D, respectively, partitioned by the vertical ribs 26 In the passages 25a and 25b, the cylinder head 20 flows from one end side to the other end side. The cooling water that has reached the other end side (the right end side in FIG. 4) of the cylinder head 20 flows out of the engine main body 4 through a water outlet member 64 attached to the outflow side of the water jacket 25.

  In this embodiment, as described above, immediately after flowing into the water jacket 5 on the cylinder block 10 side, a relatively large amount of cooling water is moved to the cylinder head 20 side via the communication paths 13A to 13C. Low temperature cooling water is secured at one end of the cylinder head 20. Further, the low-temperature cooling water is separated from the cooling water flowing in through the communication passages 13A and 13D, and is drifted into the passage 25a formed on the thrust side corresponding to the exhaust side by the vertical ribs 26. Cooling performance on the exhaust side where the temperature rises during operation is enhanced, and a temperature difference between the exhaust side and the intake side can be suppressed.

  As is clear from the above description, according to the cooling device for the engine 1 according to the present embodiment, in the water jacket 5 on the cylinder block 10 side, the cooling water is first sent to the thrust side. It is possible to ensure good cooling performance on the thrust side that becomes high temperature, and the cooling water is sent in one direction around the cylinders 2A to 2D, thereby suppressing the stagnation of the cooling water, and each cylinder 2A to 2D temperature uniformity can be enhanced. As a result, the deformation of the in-line cylinders 2A to 2D is suppressed, and the uniformity of intake charging by the intake system is increased, so that the fuel efficiency can be improved. Further, in the water jacket 25 on the cylinder head 20 side, relatively low-temperature cooling water sent through the first communication path is ensured on one end side of the cylinder head 20. Can improve the cooling performance.

  Further, when the engine body is mounted horizontally so that the crankshaft extends along the vehicle width direction in the engine room in the front part of the vehicle, it is desirable to reduce the size of the engine including the external piping. In the present embodiment, the above-described water jackets 5 and 25 are configured inside the engine body 4, whereas, outside the engine body 4, as shown in FIG. 1, one end side of the engine body 4 The water pump 52 is attached to the front side of the cylinder block 10, while the water outlet member 64 is attached to the other end side of the engine body 4, and the water pump 52 and the water outlet member 64 are respectively connected to the engine. It is connected to a cooling water inlet and outlet of a radiator (not shown) disposed on the front side of the main body 4. Thereby, on the front side of the engine main body 4, piping connected to the water jackets 5 and 25 and the radiator and forming a part of the cooling passage can be simplified, and the engine can be downsized.

  Furthermore, according to the cooling device for the engine 1 according to the present embodiment, the opening area of the communication passages 13A to 13D provided on one end side of the cylinder block 10 is set to be relatively large. Thus, since a relatively large flow rate of cooling water is moved to the cylinder head 20 side, it is possible to ensure good cooling performance on the cylinder head 20 side, which is thermally stricter than the cylinder block 10.

  Furthermore, according to the cooling device for the engine 1 according to the present embodiment, the exhaust side is cooled by the relatively low-temperature cooling water on the cylinder head 20 side, and therefore, between the exhaust side and the intake side in the cylinder head 20. The temperature difference of the engine can be suppressed, and the temperature uniformity of the entire engine can be improved. Further, since the cylinder block 10 including the top deck 12 is employed, the rigidity of the block 10 is ensured, for example, deformation of the cylinders 2A to 2D due to the influence of high heat is suppressed, and each cylinder in the engine 1 is further suppressed. When the knocking sensor (not shown) set for each of 2A to 2D can ensure the detection performance of knock vibration and the top deck 12 is provided with a hole 18 for degassing at the time of casting, the degassing is also performed. Thus, air accumulation and cooling water stagnation in the holes 18 are suppressed, and good engine cooling performance can be ensured.

  It should be noted that the present invention is not limited to the illustrated embodiments, and it goes without saying that various improvements and design changes can be made without departing from the scope of the present invention.

  The engine cooling device according to the present invention can be applied to any type of vehicle as long as it includes a vehicle such as an automobile and is equipped with an engine.

1 is a perspective view schematically showing an engine according to the present invention. It is a section explanatory view showing the composition of the water jacket of a cylinder block. It is a top view of the cylinder block provided with the top deck. It is a top view which shows roughly the state by which the cylinder head was attached to the cylinder upper side. It is longitudinal cross-sectional explanatory drawing of the said cylinder head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine 2A, 2B, 2C, 2D ... Cylinder 5 ... Cylinder block side water jacket 10 ... Cylinder block 13A, 13B, 13C, 13D ... Communication path 18 ... Gas vent hole 20 ... Cylinder head 25 ... Cylinder head side water jacket 25a ... Thrust side passage 25b ... Anti-thrust side passage 26 ... Vertical rib

Claims (4)

In a cooling device for cooling a crossflow type in-line multi-cylinder engine in which an intake system and an exhaust system are arranged on opposite sides of a cylinder head,
A passage communicating with a cooling water inflow port provided at one end side of the cylinder block or in the vicinity thereof, extending along the thrust side surface of the in-line multi-cylinder, and further anti-thrust through the other end side of the cylinder block A block cooling passage extending along a side surface and partitioned at one end of the cylinder block;
A first communication path that communicates with the block cooling path on one end side and thrust side of the cylinder block and reaches one end side of the cylinder head at an upstream position of the block cooling path;
A second communication path that communicates with the block cooling path and reaches one end side of the cylinder head on one end side and the anti-thrust side of the cylinder block at a position downstream of the block cooling path;
A head cooling passage extending from one end side of the cylinder head communicating with the first and second communication passages to the other end side of the cylinder head provided with a cooling water outflow port ,
The aforementioned cylinder head, in order to flow polarized cooling water sent through the first communication path to the exhaust side, that have longitudinal ribs of a predetermined height extending along a longitudinal direction of the cylinder head is formed An engine cooling system characterized by that. A cooling device mounted on an engine in which the in-line multi-cylinders are horizontally mounted so as to be arranged in the vehicle width direction, and an exhaust system is disposed on the rear side of the main body in the vehicle longitudinal direction corresponding to the thrust side. ,
A radiator is disposed in front of the engine body, and a water pump is disposed on the front side of the engine body on one end side of the cylinder block.
As a part of the block cooling passage, a cooling passage for supplying cooling water cooled by the radiator to the thrust side of the block cooling passage from the front of the engine body is configured on one end side of the cylinder block. The engine cooling device according to claim 1, wherein A plurality of communication passages including the first and second communication passages and communicating with the block cooling passage and the head cooling passage;
The engine cooling device according to claim 1 or 2, wherein an opening area of a communication path provided on one end side of the cylinder block and in the vicinity thereof is set to be relatively large. The cylinder block is a closed deck type block having a deck portion at the top of the water jacket, and the deck portion has a plurality of vent holes corresponding to the block cooling passage. The engine cooling apparatus according to any one of claims 1 to 3 , wherein the engine cooling apparatus is provided.

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