JP2020029824A - Internal combustion engine - Google Patents

Abstract

To cool an internal combustion engine even at a merging part of a cooling water circulation passage which is not constituted as a heat exchanger, and to improve the heat exchange efficiency of a cooling device as a whole.SOLUTION: In a cooling water circulation passage of an internal combustion engine, a merging part 105 is connected to a downstream side with respect to a radiator. The merging part 105 is partitioned by a dome-shaped part 113 of a thermostat cover 111 and a recess 122 of a first suction cover 121. An inclination wall 122A of the first suction cover 121 is parallel with an inclination wall 48 of a separator housing 46. By this constitution, high-temperature oil in the separator housing 46 can be further efficiently heat-exchanged between the inclination wall 48 of the separator housing 46 and the inclination wall of the first suction cover with respect to cooling water which flows in the merging part 105.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an internal combustion engine.

  The internal combustion engine of Patent Document 1 is a water-cooled internal combustion engine cooled by cooling water. The internal combustion engine of Patent Literature 1 includes a cooling device that cools oil in the internal combustion engine. In the cooling device, cooling water cooled by a radiator is sucked into a water pump. An oil cooler is arranged downstream of the water pump in the cooling water passage, and the cooling water sucked into the water pump is discharged to the oil cooler. A radiator is arranged downstream of the oil cooler in the cooling water passage, and the cooling water flowing through the oil cooler is returned to the radiator.

JP 2014-227921 A

  In the cooling water passage of the cooling device of Patent Document 1, there is a portion through which relatively low-temperature cooling water flows. Specifically, for example, relatively low-temperature cooling water flows through a portion of the cooling water passage from the radiator to the water pump. Therefore, a portion of the cooling water passage through which the relatively low-temperature cooling water flows has room for functioning as a portion for cooling the internal combustion engine even if it is not configured as a heat exchanger such as an oil cooler. is there. The cooling device of Patent Literature 1 has not been studied in view of this point, and there is room for further improvement in the heat exchange efficiency of the entire cooling device.

  In order to solve the above problems, the present invention provides a water pump for pumping cooling water, a cooling water circulation passage through which cooling water pumped from the water pump flows, and the cooling water is circulated to the water pump. A heat exchange portion disposed in the middle of the cooling water circulation passage, a radiator disposed downstream of the heat exchange portion in the cooling water circulation passage, and a branch from an upstream side of the radiator in the cooling water circulation passage, A branch passage bypassing the radiator and connected to the cooling water circulation passage downstream of the radiator, a blow-by gas passage for returning blow-by gas generated inside the oil pan to an intake passage, and the blow-by gas A PCV separator provided in the passage for separating oil in the blow-by gas, A cover member that defines a junction between the recirculating water circulation passage and the downstream end of the branch passage is disposed to face the separator housing that defines the internal passage of the PCV separator without any other member interposed therebetween. A part of the outer surface of the cover member, including a portion closest to the separator housing, is disposed parallel to and opposed to the outer surface of the separator housing.

  In the above configuration, relatively low-temperature cooling water flows through the junction of the cooling water circulation passage and the downstream end of the branch passage. Further, since a part of the outer surface of the cover that defines the junction is disposed so as to be opposed to the outer surface of the separator housing in parallel, the separator housing can be cooled by the cooling water in the junction. As described above, according to the above configuration, a part of the internal combustion engine can be cooled even at the junction of the cooling water circulation passage that is not configured as a heat exchanger, so that the heat exchange efficiency of the entire cooling device can be improved.

FIG. 2 is a cross-sectional view of the internal combustion engine. 1 is a partial side view of an internal combustion engine. Sectional drawing around a PCV separator. FIG. 4 is a sectional view taken along line 4-4 in FIG. 3.

One embodiment of an internal combustion engine will be described with reference to the drawings.
First, an outline of the internal combustion engine E will be described.
As shown in FIG. 1, the internal combustion engine E includes a generally rectangular parallelepiped cylinder block 10. A plurality of (for example, three) cylindrical cylinders 11 are defined inside the cylinder block 10. The cylinders 11 are arranged so as to be aligned in the direction in which the crankshaft extends in the internal combustion engine E (the thickness direction in FIG. 1). FIG. 1 shows only one of the three cylinders 11.

  A piston 12 is accommodated in each cylinder 11 of the cylinder block 10 such that the piston 12 can reciprocate in the cylinder 11. Although not shown, the piston 12 is connected to a crankshaft via a connecting rod.

  A generally rectangular parallelepiped cylinder head 20 is fixed to the upper surface of the cylinder block 10. On the lower surface of the cylinder head 20, a circular concave portion 21 is recessed upward when viewed from the axial direction of the cylinder 11. The diameter of the recess 21 is substantially the same as the diameter of the cylinder 11. The concave portion 21 is arranged to face the cylinder 11. A combustion chamber 22 is defined by the inner wall of the concave portion 21, the inner wall of the cylinder 11, and the upper surface of the piston 12.

  An intake port 23 for supplying intake air into the cylinder 11 is defined inside the cylinder head 20. The intake port 23 is disposed on one side (hereinafter, referred to as “intake side”) in a direction (left-right direction in FIG. 1) orthogonal to both the vertical direction and the extension direction of the crankshaft. . One end of the intake port 23 opens to the concave portion 21, and the other end of the intake port 23 opens to a side surface on the intake side of the cylinder head 20. The other end of the intake port 23 is connected to an intake passage 24 (intake manifold).

  The cylinder head 20 is provided with an intake valve 25 for opening and closing the opening of the intake port 23 on the concave portion 21 side. The intake valve 25 is opened and closed in conjunction with rotation of a crankshaft by a valve operating mechanism (not shown).

  An exhaust port 26 for exhausting exhaust gas from the cylinder 11 is defined inside the cylinder head 20. The exhaust port 26 is disposed on the other side (hereinafter, referred to as “exhaust side”) in a direction orthogonal to both the vertical direction and the extending direction of the crankshaft. One end of the exhaust port 26 is open to the concave portion 21, and the other end of the exhaust port 26 is open to the exhaust side of the cylinder head 20. The other end of the exhaust port 26 is connected to an exhaust passage 27 (exhaust manifold).

  Further, an exhaust valve 28 for opening and closing the opening of the exhaust port 26 on the side of the concave portion 21 is attached to the cylinder head 20. The exhaust valve 28 is opened and closed in conjunction with rotation of a crankshaft by a valve mechanism (not shown).

  A cylinder head cover 29 that covers the cylinder head 20 is fixed to an upper surface of the cylinder head 20. In a space defined by the inner surface of the cylinder head cover 29 and the upper surface of the cylinder head 20, a valve operating mechanism for opening and closing the above-described intake valve 25 and exhaust valve 28 is housed, although not shown. .

  A substantially quadrangular cylindrical crankcase 31 is fixed to the lower surface of the cylinder block 10 along the outer peripheral edge of the cylinder block 10. A storage box 32 having a bottomed rectangular box shape is fixed to a lower end surface of the crankcase 31. The crankcase 31 and the storage case 32 constitute an oil pan 30 for storing oil.

  In the cylinder block 10, a blow-by gas passage 40 for guiding the blow-by gas leaked from the inside of the cylinder 11 to the inside of the oil pan 30 to the outside is defined. The lower end of the blow-by gas passage 40 opens on the lower surface of the cylinder block 10. The upper end of the blow-by gas passage 40 opens on the side surface of the cylinder block 10 on the intake side.

  At the upper end of the blow-by gas passage 40, a PCV (Positive Crackcase Ventilation) separator 45 for liquefying and collecting oil contained in the blow-by gas is connected. The PCV separator 45 includes a separator housing 46 that defines an internal space through which the blow-by gas flows. The interior space of the separator housing 46 is partitioned by a plurality of walls, and has a so-called labyrinth structure. 1 and 3, the illustration of the wall inside the PCV separator 45 is omitted, and only the separator housing 46 is illustrated.

  From the PCV separator 45, a PCV passage 47 for guiding blow-by gas to the intake passage 24 extends. The PCV passage 47 is connected to the intake passage 24. The blow-by gas after the oil is collected in the PCV separator 45 is sucked into the intake passage 24 through the PCV passage 47 according to the negative pressure in the intake passage 24. In FIG. 1, the PCV passage 47 is shown by a simplified line.

  As shown in FIG. 2, a water pump 60 in the cooling device 50 is fixed to an outer surface on the intake side of the internal combustion engine E. The water pump 60 is an electric pump that operates by receiving power supply from a battery of the vehicle and pumps cooling water. Further, the cooling device 50 includes a cooling water circulation passage 70 through which cooling water pumped from the water pump 60 flows and through which the cooling water is circulated to the water pump 60. In FIG. 2, a part of the cooling water circulation passage 70 is simplified and shown by a line.

  The cooling device 50 includes a heat exchange unit 80 that receives the heat of the internal combustion engine E by the cooling water. The heat exchange section 80 is arranged in the middle of the cooling water circulation passage 70. The heat exchange section 80 is a water jacket surrounding the cylinder 11 in the cylinder block 10 or a water jacket defined around the exhaust port 26 in the cylinder head 20. In FIG. 2, the heat exchange unit 80 is illustrated in a simplified manner.

  The cooling device 50 includes a radiator 90 for cooling the cooling water. The radiator 90 is disposed downstream of the heat exchange unit 80 in the cooling water circulation passage 70. The radiator 90 exchanges heat between the outside air introduced into the engine room of the vehicle and the cooling water flowing through the radiator 90. FIG. 2 shows the radiator 90 in a simplified manner.

  In the cooling water circulation passage 70 of the cooling device 50, a branch passage 100 branches from the downstream side of the heat exchange unit 80 and from the upstream side of the radiator 90. The branch passage 100 bypasses the radiator 90 and is connected to the junction 105 in the cooling water circulation passage 70 downstream of the radiator 90. In FIG. 2, a part of the branch passage 100 is simplified and shown by a line.

Next, the merging portion 105 of the cooling device 50 and the separator housing 46 of the PCV separator 45 will be described more specifically.
As shown in FIG. 3, a separator housing 46 of the PCV separator 45 is fixed to a side surface of the cylinder block 10 on the intake side. The separator housing 46 has a rectangular parallelepiped shape as a whole.

  When the cross section of the separator housing 46 is viewed from the direction in which the crankshaft extends, the lower portion of the wall of the separator housing 46 opposite to the cylinder block 10 is inclined so as to be positioned closer to the cylinder block 10 as it goes downward. An inclined wall 48 is provided.

  As shown in FIG. 2, a suction cover 120 is fixed to a side surface of the cylinder block 10 on the intake side. The suction cover 120 is roughly divided into a first suction cover 121, a second suction cover 126, and a suction passage 136 connecting the first suction cover 121 and the second suction cover 126.

  Among the suction covers 120, the first suction cover 121 is arranged on a side opposite to the cylinder block 10 with respect to the separator housing 46. The first suction cover 121 has a rectangular plate shape as a whole when viewed from the intake side. When viewed from the intake side, the entire area of the first suction cover 121 is located within the range of the separator housing 46.

  As shown in FIG. 3, a concave portion 122 that is concave toward the cylinder block 10 is concaved at a substantially central portion of the first suction cover 121. The concave portion 122 is circularly concave when viewed from the intake side. When the first suction cover 121 is viewed in cross section from the direction in which the crankshaft extends, an inclined wall in which the upper part of the wall part defining the concave portion 122 in the first suction cover 121 is inclined such that the lower part is located closer to the cylinder block 10 side. 122A.

  The inclined wall 122A of the first suction cover 121 is opposed to the inclined wall 48 of the separator housing 46 so as to be parallel. The separator housing 46 and the suction cover 120 are closest to each other at a portion where the inclined wall 122A and the inclined wall 48 face each other. The distance between the inclined wall 122A and the inclined wall 48 is, for example, several centimeters or less. Further, no other member is interposed between the inclined wall 122A and the inclined wall 48, and a space through which air can flow is provided therebetween.

  In the concave portion 122 of the first suction cover 121, a first passage hole 125 penetrates a side surface on the other side (the lower side in FIG. 2 and the near side in FIG. 3) in the extending direction of the crankshaft. In FIG. 3, the position of the first passage hole 125 is indicated by a two-dot chain line.

  As shown in FIG. 2, one end of a tubular suction passage 136 is connected to the first passage hole 125 of the first suction cover 121. The suction passage 136 extends in the direction in which the crankshaft extends.

  At the end of the suction passage 136 opposite to the first suction cover 121, a second suction cover 126 having a bottomed cylindrical shape as a whole is disposed. The second suction cover 126 is arranged so that the axial direction of the second suction cover 126 is along the vertical direction. A second passage hole 127 is opened on the outer peripheral surface of the second suction cover 126. The second passage hole 127 is located below the axial center of the second suction cover 126. The second suction cover 126 is connected to the suction passage 136 at the second passage hole 127.

  The upper end of the second suction cover 126 is curved such that the upper end faces the intake side surface of the cylinder block 10. A cylinder block opening 128 is opened at an upper end of the second suction cover 126. The cylinder block opening 128 is connected to a water supply port (not shown) opened on the intake side surface of the cylinder block 10.

  A flat plate portion 129 extends from the upper end of the second suction cover 126. The flat portion 129 extends along the intake side surface of the cylinder block 10. Bolts B are inserted through the flat plate portion 129 in the thickness direction of the flat plate portion 129, and the suction cover 120 is fixed to the intake side surface of the cylinder block 10 by the bolts B.

  Note that the water pump 60 is arranged adjacent to the second suction cover 126. The water pump 60 is connected by a water pump opening 131 that opens to the second suction cover 126. The impeller of the water pump 60 is arranged inside the water pump 60. Then, when the water pump 60 is driven to rotate the impeller, the cooling water is sucked from the suction passage 136, passes through the second suction cover 126, and is pressure-fed to the cylinder block 10 from the cylinder block opening 128. . In the present embodiment, the rotation axis of the impeller of the water pump 60 is along the axial direction of the crankshaft. The impeller rotates from the lower side to the upper side on the side opposite to the cylinder block 10 from the rotation axis, and rotates from the upper side to the lower side on the cylinder block 10 side from the rotation axis.

  As shown in FIGS. 2 and 3, a thermostat 110 is arranged on the first suction cover 121 on the side opposite to the cylinder block 10. The thermostat 110 includes a thermostat cover 111 that partitions an internal space through which the cooling water flows.

  As shown in FIG. 2, the thermostat cover 111 has a rectangular plate shape as a whole when viewed from the intake side. Further, when viewed from the intake side, the thermostat cover 111 has the same size as the first suction cover 121 and is arranged to face the first suction cover 121.

  As shown in FIG. 3, a dome-shaped portion 113 is recessed at a substantially central portion of the thermostat cover 111 on a side opposite to the cylinder block 10. The dome-shaped portion 113 is depressed in a circular shape when viewed from the cylinder block 10 side. The dome portion 113 and the concave portion 122 of the first suction cover 121 are arranged to face each other. The junction 105 is defined by the dome 113 of the thermostat cover 111 and the recess 122 of the first suction cover 121. In other words, the thermostat cover 111 and the first suction cover 121 serve as a cover member that partitions the junction 105 between the cooling water circulation passage 70 and the downstream end of the branch passage 100.

  Bolts B are inserted outside the dome-shaped portion 113 of the thermostat cover 111 and outside the concave portion 122 of the first suction cover 121. The thermostat cover 111 is fixed to the intake side of the first suction cover 121 by bolts B.

  At an end of the thermostat cover 111 opposite to the cylinder block 10, a radiator cooling water inflow portion 112 into which cooling water having passed through the radiator 90 flows is provided. As shown in FIG. 3, the radiator cooling water inflow portion 112 has a circular tubular shape. The radiator cooling water inflow portion 112 extends obliquely so as to be located lower as it goes closer to the side opposite to the cylinder block 10 (in the direction of cooling water flow, toward the radiator 90). In addition, a part of the radiator cooling water inflow portion 112 is configured to be inserted into the junction 105. In this embodiment, the radiator cooling water inflow portion 112 is formed integrally with the thermostat cover 111.

  As shown in FIGS. 3 and 4, the thermostat cover 111 of the thermostat 110 houses a rod-shaped temperature sensing portion 114 as a whole. One end of the temperature sensing section 114 is fixed to the inner wall of the thermostat cover 111. The other end of the temperature sensing section 114 is not in contact with the inner wall of the thermostat cover 111, and is located substantially at the center of the junction 105. Although not shown, the valve of the thermostat 110 is opened and closed according to the temperature of the cooling water hitting the temperature sensing unit 114, and the amount of cooling water flowing from the radiator cooling water inflow unit 112 is controlled. In FIG. 3, the temperature sensing part 114 of the thermostat 110 is indicated by a two-dot chain line.

  In the thermostat cover 111, a branch passage inlet 115 is opened on a side surface on one side in the direction in which the crankshaft extends (the back side in the drawing in FIG. 3, the right side in FIG. 4). A circular branch pipe 103 is connected to one side of the branch passage inlet 115 in the direction in which the crankshaft extends. The branch pipe 103 forms a part of the branch passage 100 on the downstream side. In FIG. 2, the branch passage 100 is shown by a simplified line except for a part on the downstream side of the branch pipe 103.

  A protruding wall 102 protrudes from an upper inner wall of the opening 101 of the branch pipe 103 on the thermostat cover 111 side. The protruding wall 102 is inclined so as to go downward as it approaches the end of the branch pipe 103 on the thermostat cover 111 side. The protruding wall 102 protrudes from the inner wall of the opening 101 in a range of approximately one third above the opening 101 in the circumferential direction. When viewed from the direction in which the crankshaft extends, the lower edge of the protruding wall 102 (the edge on the protruding tip side) is higher toward the center of the protruding range, and lower on both sides of the protruding range. That is, when viewed from the direction in which the crankshaft extends, the protruding wall 102 has a crescent shape concave downward.

Next, the flow of the cooling water will be described.
The cooling water pumped from the water pump 60 flows through the second suction cover 126 which is a part of the cooling water circulation passage 70. The cooling water flowing through the second suction cover 126 flows into the heat exchange section 80 (water jacket) in the cylinder block 10 through the cylinder block opening 128 in the second suction cover 126. The cooling water flowing into the heat exchange unit 80 is heated by the heat exchange unit 80 by absorbing heat. A part of the cooling water heated in the heat exchange unit 80 flows into the radiator 90 through the cooling water circulation passage 70, and the rest flows into the junction 105 through the branch passage 100. The cooling water that has flowed into the radiator 90 is cooled by the radiator 90 and flows into the junction 105.

  At the junction 105, the cooling water flowing from the radiator 90 passes through the radiator cooling water inlet 112, hits the upper surface in the thermostat cover 111, and flows along the inclined wall 122 </ b> A of the first suction cover 121. That is, the cooling water flows in the first suction cover 121 so as to swirl in an arc shape (counterclockwise in FIG. 3) in the order of the upper part, the inclined wall 122A side, and the lower part. Since the inclined wall 122A is inclined so as to be positioned closer to the cylinder block 10 as it goes downward, the inclined wall 122A is inclined so as to follow the arc-shaped flow of the cooling water in the first suction cover 121.

  On the other hand, the cooling water flowing from the branch passage 100 flows into the junction 105 from the branch passage inlet 115. Since the protruding wall 102 protrudes from the opening 101 of the branch pipe 103, the cooling water flows toward the side opposite to the side where the protruding wall 102 protrudes. That is, the cooling water flows from the branch passage inlet 115 toward the lower surface of the thermostat cover 111.

  The cooling water joined at the junction 105 passes through the suction passage 136 and is sucked into the space in which the impeller of the water pump 60 defined by the water pump opening 131 of the second suction cover 126 is accommodated.

The operation and effect of the present embodiment will be described.
(1) In the present embodiment, the cooling water cooled by the radiator 90 flows into the junction 105 and flows along the inclined wall 122A. Since the cooling water cooled by the radiator 90 flows into the junction 105, relatively low-temperature cooling water flows. On the other hand, when the oil contained in the blow-by gas is liquefied and collected, high-temperature oil is stored in the separator housing 46.

  Since the inclined wall 122A of this embodiment and the inclined wall 48 of the separator housing 46 are arranged close to each other, the oil inside the separator housing 46 can be cooled by the cooling water inside the first suction cover 121. Moreover, in the present embodiment, the inclined wall 122A of the first suction cover 121 and the inclined wall 48 of the separator housing 46 are parallel to each other, and a corresponding area is secured as a heat exchange area. Therefore, the oil in the separator housing 46 easily radiates heat to the cooling water flowing through the junction, and the PCV separator 45 can be cooled even at the junction 105 that is not configured as a heat exchanger. Therefore, the heat exchange efficiency of the entire cooling device 50 can be improved.

  (2) In the present embodiment, the flow direction of the cooling water flowing from the radiator cooling water inflow portion 112 to the inclined wall 122A and the rotation direction of the impeller of the water pump 60 are the same at the junction 105. Has become. Further, the inclined wall 122A is inclined so as to follow the arc-shaped flow of the cooling water in the first suction cover 121. Therefore, it is difficult to hinder the flow of the cooling water in the inclined wall 122A. Therefore, since the speed of the cooling water transmitted through the inclined wall 122A does not easily decrease, heat can be more efficiently exchanged with the inclined wall 48 of the separator housing 46.

  (3) In the present embodiment, since the protruding wall 102 projects from the opening 101 at the downstream end of the branch passage 100, when the cooling water flowing through the branch passage 100 flows into the junction 105, the cooling water The air flows obliquely toward the direction opposite to the protruding wall 102 side. Therefore, the cooling water flows toward the lower inner wall of the thermostat cover 111. Therefore, the cooling water flowing from the radiator 90 flowing along the upper surface of the thermostat cover 111 is unlikely to obstruct the flow until the cooling water travels along the inclined wall 122A. Therefore, since the speed of the relatively low-temperature cooling water transmitted through the inclined wall 122A is hard to decrease, heat can be more efficiently exchanged with the inclined wall 48 of the separator housing 46.

The above embodiment can be modified and implemented as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
Of the walls of the separator housing 46, the wall of the first suction cover 121 that is opposed to the wall of the first suction cover 121 does not need to be inclined and may extend vertically. In this case, of the walls of the first suction cover 121, the wall parallel to the wall of the separator housing 46 also extends in the vertical direction.

  In a portion of the wall of the separator housing 46 other than the inclined wall 48, that is, in a portion where the interval with respect to the first suction cover 121 is not minimum, the wall may be arranged to face the wall of the first suction cover 121 in parallel. . Even if the space with respect to the first suction cover 121 is somewhat large, if the wall of the separator housing 46 and the wall of the first suction cover 121 are arranged in parallel and opposed to each other, there is room for heat exchange between them.

  The configuration of the cover member that defines the junction 105 is not limited to the example of the above embodiment. For example, the cover member may be configured by disposing two covers in the up-down direction. In this case, a part of the wall of at least one of the two covers may be disposed so as to be opposed to the inclined wall 48 of the separator housing 46 in parallel.

  -Furthermore, the cover member which divides the junction 105 is not limited to the one configured by the two members. For example, one integral cover member may define the junction 105, and three or more members may define the junction 105. Even in this case, if a part of the wall of the cover member is parallel to the inclined wall 48 of the separator housing 46, a part of the wall of the cover member and the inclined wall 48 of the separator housing 46 Heat exchange becomes easier.

  The extending direction of the inclined wall 122A can be designed irrespective of the direction in which the cooling water flows in the junction 105. For example, when the extending direction of the inclined wall 122A intersects with the direction in which the cooling water flows, although the cooling water is prevented from flowing by the inclined wall 122A, the cooling water hits the inclined wall 122A, so that the inclined wall 122A is formed. Is easily cooled. Therefore, the extending direction of the inclined wall 122A may be designed in consideration of the balance between the flow resistance of the cooling water and the amount of heat of the separator housing 46 to be cooled by the inclined wall 122A.

  The opening direction of the radiator cooling water inflow portion 112 does not have to be obliquely upward toward the cylinder block 10 side. For example, the opening direction of the radiator cooling water inflow portion 112 may be obliquely downward toward the cylinder block 10. For example, if the discharge capacity of the water pump 60 is appropriately large, the influence of the opening direction of the radiator cooling water inflow portion 112 on the discharge performance of the water pump 60 is reduced.

  The protruding wall 102 in the opening 101 of the branch passage 100 does not have to protrude from the upper side. For example, the protruding wall 102 may protrude from the inner wall of the opening 101 on the cylinder block 10 side. Even in this case, if the radiator cooling water inflow portion 112 is opened obliquely upward on the cylinder block 10 side at the junction 105, the flow of the cooling water flowing from the radiator cooling water inflow portion 112 is obstructed. Hateful.

  -The protruding wall 102 in the opening 101 of the branch passage 100 may not be provided. In this case, it is more preferable that the cooling water flowing from the opening 101 of the branch passage 100 into the junction 105 hardly obstruct the flow of the cooling water flowing from the radiator cooling water inlet 112.

  The position of the branch passage 100 may be branched from the upstream side of the heat exchange unit 80 in the cooling water circulation passage 70. In addition, there may be a plurality of branch passages 100, and the branch passage 100 may further branch in the middle.

  An oil cooler may be used as the heat exchange unit 80. In this case, the oil in the internal combustion engine E also exchanges heat with the oil cooler by the heat exchange unit 80, so that the internal combustion engine E is more easily cooled.

The cooling device 50 may not be fixed to the intake side surface of the cylinder block 10. For example, the cooling device 50 may be fixed to the exhaust side surface of the cylinder block 10.
-The water pump may be mechanical. For example, a water pump driven by rotation of a crankshaft may be used.

  DESCRIPTION OF SYMBOLS 10 ... cylinder block, 11 ... cylinder, 12 ... piston, 20 ... cylinder head, 21 ... recessed part, 22 ... combustion chamber, 23 ... intake port, 24 ... intake passage, 25 ... intake valve, 26 ... exhaust port, 27 ... exhaust Passageway 28 Exhaust valve 29 Cylinder head cover 30 Oil pan 31 Crankcase 32 Storage case 40 Blow-by gas passage 45 PCV separator 46 Separator housing 47 PCV passage 48 Inclined wall, 50 cooling device, 60 water pump, 70 cooling water circulation passage, 80 heat exchange section, 90 radiator, 100 branch passage, 101 opening, 102 projecting wall, 103 branch pipe, 105 ... junction, 110 ... thermostat, 111 ... thermostat cover, 112 ... radiator cooling water inlet, 113 ... Boom-shaped part, 114 ... temperature sensing part, 115 ... branch passage inflow, 120 ... suction cover, 121 ... first suction cover, 122 ... recess, 122A ... inclined wall, 125 ... first passage hole, 126 ... second Suction cover, 127: second passage hole, 128: cylinder block opening, 131: water pump opening, 136: suction passage, B: bolt, E: internal combustion engine.

Claims (1)

A water pump for pumping cooling water,
A cooling water circulation passage through which cooling water pumped from the water pump flows, and the cooling water is circulated to the water pump,
A heat exchange unit arranged in the middle of the cooling water circulation passage,
A radiator disposed downstream of the heat exchange unit in the cooling water circulation passage;
A branch passage that branches from the upstream side of the radiator in the cooling water circulation passage, and is connected to the cooling water circulation passage downstream of the radiator in bypass of the radiator;
A blow-by gas passage for returning blow-by gas generated inside the oil pan to the intake passage;
A PCV separator provided in the blow-by gas passage to separate oil in the blow-by gas;
An internal combustion engine comprising:
A cover member that defines a junction between the cooling water circulation passage and the downstream end of the branch passage is disposed so as to face the separator housing that defines the internal passage of the PCV separator without any other member interposed therebetween. Yes,
An internal combustion engine in which a part of the outer surface of the cover member, including a portion closest to the separator housing, is disposed in parallel to the outer surface of the separator housing.