JP2012036815A - Coolant water passage structure of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coolant water passage structure of an internal combustion engine that prevents air from staying in a passage in which a coolant water flows to obtain stable cooling.SOLUTION: The structure includes: a water jacket 22 in which the coolant water flows; a coolant water introducing passage 31 which introduces the coolant water from the water jacket 22; a main water jacket 32 which diverges from the coolant water introducing passage 31 and extends in the same direction as an arrangement direction of a cylinder 21b, and in which the coolant water circulates to a radiator 20; a sub water jacket 33 which diverges from the coolant water introducing passage 31; and a circulating passage 35 in which the coolant water circulates from an opposite-side end port 33b to the water jacket 22, the opposite-side end port being positioned on an opposite side of a branch port 33a formed at a part where the sub water jacket 33 is branched. The structure further includes a bottom bypass passages 23 which communicates the opposite-side end port 33b of the sub water jacket 33 with the main water jacket 32.

Description

  The present invention relates to a cooling water passage structure for an internal combustion engine, and more particularly to a cooling water passage structure for an internal combustion engine formed inside a cylinder head and a cylinder block.

  Conventionally, as a cooling water passage structure of this type of internal combustion engine, an exhaust port and an intake port that are opened in a cylinder formed in a cylinder block, an exhaust valve seat ring that is fitted into an opening portion of the exhaust port, an exhaust port, A main cooling water passage provided between the intake port and extending in the cylinder arrangement direction, and provided on the lower side of the exhaust port so as to pass in the vicinity of the exhaust valve seat ring and extending in the cylinder arrangement direction. A sub-cooling water passage narrower than the passage, a supply passage for supplying cooling water from the cooling water passage formed in the cylinder block to the sub-cooling water passage, and a bolt hole through which a bolt fixed to the cylinder block is inserted The communication passage that connects the main cooling water passage and the sub cooling water passage is a bolt made of a meat portion around the bolt hole in the vicinity of the exhaust valve seat ring. Cooling structure of a cylinder head formed in the boss portion is known (for example, see Patent Document 1).

  In the cooling water passage structure of the cylinder head, a communication passage that connects the main cooling water passage and the sub cooling water passage is formed, so that the cooling water flowing in the sub cooling water passage having a complicated and complicated shape is Then, it smoothly flows to the main cooling water passage through this communication passage. As a result, the cooling water in the sub cooling water passage does not stagnate in the vicinity of the exhaust valve seat ring, and the exhaust valve seat ring portion is cooled.

JP-A-6-185403

However, in the conventional cooling structure of the cylinder head, since the communication path is formed, the circulation of the cooling water in the exhaust valve seat ring part is improved and the cooling of the exhaust valve seat ring part is promoted. There is a possibility that air stays in the water passage and obstructs the flow of the cooling water in the sub cooling water passage.
That is, in the conventional cooling structure of the cylinder head, since air retention is not taken into consideration, a portion of the sub cooling water passage that is separated from the communication portion between the sub cooling water passage and the communication passage, for example, the sub cooling water passage Air has accumulated in the corners and ends of the inside. At such corners and ends in the sub-cooling water passage, air is likely to stay, and since the discharge path of the staying air is not considered, it is difficult to suppress the stay of air. In particular, in the case of an engine having a slant in a so-called front-rear direction in which the engine is mounted on the vehicle so that the front side of the vehicle is high and the rear side of the vehicle is low with respect to the vehicle, a corner portion in the sub-cooling water passage And the end is located on the front side of the engine and is formed to be relatively high in the sub-cooling water passage, air stays at the corners and ends in the sub-cooling water passage. easy.

Thus, if air stays at the corners or ends in the sub-cooling water passage, smooth circulation of the cooling water in the sub-cooling water passage may be hindered, and stable cooling may not be obtained. It was.
In particular, during the engine warm-up operation in which the coolant is circulated through the bypass passage without passing through the radiator, the amount of coolant flowing into the cylinder block that is relatively high in the sub-coolant passage is insufficient. However, there has been a problem that the temperature rise of the cylinder block is not promoted and the efficient heat exchange of the engine may not be promoted. Due to such a decrease in the efficiency of heat exchange, there has been a problem that the so-called fuel efficiency of the engine may not be improved.

  The present invention has been made in order to solve the above-described conventional problems, and it is possible to prevent air from staying in a passage through which cooling water flows, and to provide an internal combustion engine that can achieve stable cooling. It is an object to provide a cooling water passage structure.

  In order to solve the above problems, a cooling water passage structure for an internal combustion engine according to the present invention includes (1) a cylinder peripheral passage for circulating cooling water radiated by a heat exchanger around the cylinder, and the cooling water to the cylinder. A cooling water introduction passage that is introduced from a peripheral passage into a cylinder head having an exhaust port, and extends from the cooling water introduction passage and extends in the same direction as the arrangement direction of the cylinders, and the cooling water that has cooled the cylinder head is A main cooling water passage that can be recirculated to the heat exchanger, a sub cooling water passage that branches from the cooling water introduction passage and allows the cooling water to flow in the vicinity of the exhaust port, and the cooling water introduction passage of the sub cooling water passage A recirculation passage for recirculating the cooling water from the opposite end port located on the opposite side of the branch port formed in the portion branched from the cylinder to the cylinder peripheral passage. A cooling water passage structure of the engine, characterized by comprising a main and sub communication passage for communicating the opposite end port of the sub cooling water passage to said main coolant passage.

With this configuration, the periphery of the cylinder is cooled by the cooling water flowing through the cylinder surrounding passage, the inside of the cylinder head is cooled by the cooling water flowing through the main cooling water passage, and exhausted by the cooling water flowing through the sub cooling water passage. The peripheral part of the port is cooled.
Further, the cooling water flowing through the auxiliary cooling water passage flows into the main cooling water passage through the main circulation passage and the route circulating through the circulation passage at the opposite end port and circulating to the cylinder peripheral passage. Branch to the route. Also, the cooling water that has circulated through the main cooling water passage is circulated through the circulation passage to the heat exchanger, the main auxiliary communication passage, the circulation passage through the opposite end port, and is circulated to the cylinder peripheral passage. Branches to a route.
Therefore, in the cooling water passage structure of the internal combustion engine according to the present invention, the cooling water is returned to the cylinder surrounding passage through the cylinder surrounding passage, the cooling water introduction passage, the main cooling water passage, the main auxiliary communication passage, and the circulation passage in order. Then, a bypass circulation route can be circulated through a circulation passage including a cylinder surrounding passage, a cooling water introduction passage, a sub-cooling water passage, a circulation passage, and a circulation passage that passes back to the cylinder surrounding passage.
On the other hand, in the cooling water passage structure of the internal combustion engine according to the present invention, the cooling water flows in order through the cylinder peripheral passage, the cooling water introduction passage, and the main cooling water passage and flows into the heat exchanger, in order, the cylinder peripheral passage, and the cooling water. Via a heat exchanger, consisting of a path through the water introduction path, sub-cooling water path, main sub-communication path, main cooling water path and flowing into the heat exchanger, and a path flowing out from the heat exchanger to the cylinder peripheral path It is possible to distribute the heat dissipation distribution route.
As a result, the cooling water flowing through the sub cooling water passage always flows through the opposite end port regardless of whether the bypass distribution route or the heat dissipation distribution route is used. In the conventional cooling water passage structure, it is suppressed that air stays in the port, and in the conventional cooling water passage structure, there is a problem of stagnant air that is difficult to discharge because it stays in the opposite end port that becomes the corner portion of the sub cooling water passage. Solved.

  In the cooling water passage structure for an internal combustion engine according to (1) above, (2) the main and secondary communication passages are perpendicular to a flat road surface on which the internal combustion engine is mounted on a vehicle and the vehicle is placed. The auxiliary cooling water passage is located above the opposite end port.

  With this configuration, the main sub-communication passage is located above the opposite end port of the sub cooling water passage, so that air can be more reliably prevented from staying in the opposite end port, and the conventional cooling water passage can be prevented. In the structure, the problem of stagnant air that has accumulated in the opposite end port that becomes the corner portion of the sub cooling water passage and has been difficult to discharge is solved.

  In the cooling water passage structure for an internal combustion engine according to the above (1) or (2), (3) branching from the cooling water introduction passage and extending in the same direction as the main cooling water passage, and at the opposite end port An opposing cooling water passage having an opposing end port that is formed at an opposing position and communicates with the main cooling water passage is provided, and the main auxiliary communication passage communicates with the main cooling water passage via the opposing end port. It is characterized by that.

With this configuration, the components in the cylinder head, for example, the lash adjuster, are further cooled by the cooling water flowing through the counter cooling water passage.
And the path | route into which the cooling water which distribute | circulated the opposing cooling water channel | path flows into a recirculation channel via an opposing edge part port, a main auxiliary communication path, and an opposite side edge part port is added to the above-mentioned bypass circulation route.
In addition, a route through which the cooling water flowing through the counter cooling water passage flows into the main cooling water passage through the counter end port is added to the above-described heat dissipation distribution route.
In either case of the bypass circulation route and the heat dissipation circulation route including the route that circulates through the opposing cooling water passage, the cooling water that circulates in the cylinder head always circulates through the opposite end port. Air staying in the side end port is suppressed, and in the conventional cooling water passage structure, stagnant air that has remained in the opposite end port that becomes the corner portion of the sub cooling water passage and is difficult to discharge. The problem is solved.

  In the cooling water passage structure for an internal combustion engine according to the above (1) or (2), (4) provided between the heat exchanger and the cylinder peripheral passage, and the cooling water in the heat exchanger is A water pump that pumps into a cylinder peripheral passage, and a thermostat that is provided in a flow path of the cooling water between the water pump and the heat exchanger and has a communication port that communicates with the circulation passage. And

  With this configuration, the cooling water distribution route is selected as either the bypass distribution route or the heat dissipation distribution route by the thermostat provided in the distribution route between the water pump and the heat exchanger. For example, when the temperature of the cooling water is lower than the set temperature, the thermostat switches to the bypass circulation route, and the cooling water flows through the internal combustion engine without passing through the heat exchanger. It can contribute to driving. Even in the case of such a bypass circulation route, since it flows through the opposite end port, it is possible to suppress air from staying in the opposite end port, and in the conventional cooling water passage structure, The problem of stagnant air that has remained in the opposite end port that becomes the corner and has been difficult to discharge is solved. Moreover, since the air in the sub-cooling water passage is discharged, stable cooling is obtained and warm-up performance is improved.

  In the cooling water passage structure for an internal combustion engine according to the above (1) or (2), (5) the auxiliary engine is mounted on a vehicle and the sub-direction is perpendicular to a vertical direction on a flat road surface on which the vehicle is placed. The opposite end port of the cooling water passage is located above the branch port.

  With this configuration, in particular, in the case of an internal combustion engine that has a slant that rises front and does not have left and right slants, the conventional cooling water passage structure tends to stay in the sub cooling water passage and is difficult to discharge. In the cooling water passage structure for an internal combustion engine according to the present invention, air is reliably discharged from the main / sub-communication passage. As a result, stable cooling is obtained and warm-up performance is improved.

  According to the present invention, it is possible to provide a cooling water passage structure for an internal combustion engine that can prevent air from staying in a passage through which cooling water flows and that can achieve stable cooling.

It is a lineblock diagram of an internal combustion engine and a radiator provided with a cooling water passage structure concerning an embodiment of the present invention. It is a top view of a cylinder block of an internal-combustion engine provided with a cooling water passage structure concerning an embodiment of the present invention. It is sectional drawing of the cylinder block and cylinder head containing the thermostat part of the internal combustion engine provided with the cooling water channel | path structure which concerns on embodiment of this invention. It is a top view of the cylinder head of the internal combustion engine provided with the cooling water passage structure concerning the embodiment of the present invention. It is a bottom view of the cylinder head of the internal combustion engine provided with the cooling water passage structure concerning the embodiment of the present invention. It is a left view of the cylinder head seen from B of FIG. It is a right view of the cylinder head seen from C of FIG. It is a front view of the cylinder head seen from D of FIG. It is sectional drawing which shows the AA cross section of FIG. It is a perspective view showing the passage of the cooling water which consists of the internal space of the cylinder head of the internal combustion engine provided with the cooling water passage structure concerning the embodiment of the present invention. It is a bottom view of the passage of the cooling water of the cylinder head seen from E of FIG. It is a top view of the channel | path of the cooling water of the cylinder head seen from F of FIG. It is a front view of the passage of the cooling water of the cylinder head seen from G of FIG. It is sectional drawing of the state in which the thermostat of the internal combustion engine provided with the cooling water channel | path structure which concerns on embodiment of this invention opened. It is a lineblock diagram of an internal combustion engine and a radiator provided with a cooling water passage structure concerning an embodiment of the present invention, and shows a state where cooling water circulates via a bottom bypass passage. It is a fragmentary sectional view of a cylinder head of an internal-combustion engine provided with a cooling water passage structure concerning an embodiment of the present invention, and shows a state where cooling water distributes through a bypass passage when a thermostat is closed. It is a fragmentary sectional view of a cylinder head of an internal-combustion engine provided with a cooling water passage structure concerning an embodiment of the present invention, and shows a state where cooling water distributes through a bypass passage. It is a top view of a cylinder head of an internal-combustion engine provided with a cooling water passage structure concerning an embodiment of the present invention, and shows a state where cooling water circulates via a bottom bypass passage. It is a lineblock diagram of an internal combustion engine and a radiator provided with a cooling water passage structure concerning an embodiment of the present invention, and shows a state where cooling water circulates via a radiator. It is sectional drawing of the cylinder block and cylinder head containing the thermostat part of the internal combustion engine provided with the cooling water channel | path structure which concerns on embodiment of this invention, and shows the state through which cooling water circulates via a bottom bypass channel. It is sectional drawing of the cylinder block and cylinder head containing the thermostat part of the internal combustion engine provided with the cooling water channel | path structure which concerns on embodiment of this invention, and shows the state in which cooling water circulates via a radiator.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a cooling water passage structure for an internal combustion engine according to the present invention will be described with reference to the drawings.

(Embodiment)
1 to 20 show an engine 10 and a radiator 20 of a vehicle 1 to which a cooling water passage structure of an internal combustion engine according to an embodiment of the present invention is applied.
The vehicle 1 is composed of a front engine rear wheel drive vehicle (FR), and includes an engine 10 as an internal combustion engine, an outlet 20a, and an inlet 20b, and circulates cooling water in the engine 10. And a radiator 20 as a heat exchanger. The engine 10 constituting the vehicle 1 is slanted in a so-called front-rear direction in which the front side of the vehicle 1 is inclined with respect to a vertical direction perpendicular to a flat road surface on which the vehicle 1 is placed, and the rear side of the vehicle 1 is lowered. The left-right direction of the vehicle 1 is comprised by the engine mounted in the horizontal state without inclination.

The engine 10 may be a so-called slantless engine mounted horizontally in the front-rear direction, or may be an engine having a slant in the left-right direction.
Moreover, although the engine 10 is comprised with the engine of the inline 4 cylinder, you may be comprised with the engine which has another structure. For example, it may be a single cylinder, a multi-cylinder such as 3 cylinders, 6 cylinders, etc., a vertically or horizontally installed engine, or a V-type engine.
Further, it may be a gasoline engine or a diesel engine.
Moreover, the vehicle 1 may be comprised with the front-wheel drive vehicle (FF: Front engine Front drive).

  As shown in FIG. 1, the engine 10 includes a cylinder block 11, a cylinder head 12, a crankshaft 13 supported by the cylinder block, a crank pulley 14 fixed to the crankshaft 13, a water pump 15, A cylinder head gasket sandwiched between the ribbed belt 16, a thermostat 17 provided between the water pump 15 and the radiator 20, and the cylinder block 11 and the cylinder head 12 so as to enhance the sealing performance of the contact portion between them. 18.

  As shown in FIGS. 1 to 3, the cylinder block 11 is made of a metal material such as a lightweight aluminum alloy, and includes cylinders 21a, 21b, 21c, and 21d that accommodate pistons (not shown), and a water jacket 22 as a cylinder peripheral passage. A bottom bypass passage 23 as a circulation passage, a water pump support portion 24 for supporting the water pump 15, a thermostat connecting portion 25 for supporting the thermostat 17, and a crankshaft support (not shown) for rotatably supporting the crankshaft 13. Part.

The water jacket 22 includes a water jacket portion 22a formed around the cylinders 21a, 21b, 21c, and 21d, and a water jacket formed on the vehicle front side so that cooling water supplied from the radiator 20 flows into the water jacket portion 22a. It has a jacket inlet 22b and a water jacket outlet 22c formed on the vehicle rear side.
The water jacket 22 uses the water jacket inlet 22b, the water jacket 22a and the water jacket outlet for cooling water radiated by the radiator 20 so as to cool the peripheral portions of the heated cylinders 21a, 21b, 21c, 21d by heat exchange. The part 22 c is circulated and configured to be supplied into the cylinder head 12.

  The bottom bypass passage 23 is formed on the front side of the vehicle in the cylinder block 11, and allows cooling water that has circulated in the cylinder head 12 to circulate in the thermostat 17.

  As shown in FIGS. 1 and 3 to 9, the cylinder head 12 is formed of a metal material such as a lightweight aluminum alloy, like the cylinder block 11, and accommodates an intake camshaft and an exhaust camshaft (not shown). At the same time, a lash adjuster (HLA) that adjusts the clearance so as to eliminate the gap between each cam of the intake camshaft and the exhaust camshaft and the valve rocker arm is accommodated.

  As shown in FIG. 5, the cylinder head 12 has, on its bottom surface 12a side, a pair of intake ports 42a communicating with the cylinder 21a of the cylinder block 11 and opened and closed by an unillustrated intake valve and opened and closed by an unillustrated exhaust valve. Provided with a combustion chamber 41a having an exhaust port 43a and a spark plug hole 44a. Similarly to the combustion chamber 41a, the combustion chamber 41b having a pair of intake ports 42b and a pair of exhaust ports 43b and a spark plug hole 44b communicating with the cylinder 21b, and the pair of intake ports 42c and a pair of exhausts communicating with the cylinder 21c. A combustion chamber 41c having a port 43c and a pair of spark plug holes 44c, and a combustion chamber 41d having a pair of intake ports 42d and a pair of exhaust ports 43d and a spark plug hole 44d in communication with the cylinder 21d.

  As shown in FIGS. 4 and 6, the cylinder head 12 has an intake port 45a communicating with the combustion chamber 41a via a pair of intake ports 42a on the left side as viewed from B of FIG. An intake port 45b that communicates with the combustion chamber 41b via the intake port 42b, an intake port 45c that communicates with the combustion chamber 41c via a pair of intake ports 42c, and a combustion chamber 41d that communicates via a pair of intake ports 42d An intake port portion 45 including an intake port 45d is provided.

  As shown in FIGS. 4 and 7, the cylinder head 12 has an exhaust port portion 46a communicating with the combustion chamber 41a via a pair of exhaust ports 43a on the right side viewed from C in FIG. The exhaust port portion 46b communicated with the combustion chamber 41b through the exhaust port 43b, the exhaust port portion 46c communicated with the combustion chamber 41c through the pair of exhaust ports 43c, and the combustion chamber 41d through the pair of exhaust ports 43d. An exhaust port portion 46 including an exhaust port portion 46d communicating with the exhaust port portion 46d is provided.

  As shown in FIG. 8, the cylinder head 12 is provided with a connecting portion 47 having a connecting passage 47a connected to the inlet 20b of the radiator 20 on the front side as viewed from D of FIG. Through this connection passage 47a, the cooling water flowing through the cylinder head 12 is circulated to the radiator 20.

  As shown in FIGS. 1 and 10, the cylinder head 12 includes a cooling water introduction passage 31 defined by spaces therein, a main water jacket 32 as a main cooling water passage, and a sub cooling water passage. Sub-water jacket 33, HLA cooling jacket 34 as an opposing cooling water passage, recirculation passage 35, upper bypass passage 36 that connects HLA cooling jacket 34 and main water jacket 32, and bypass as a main and sub-communication passage A passage 37 is provided.

  The cooling water introduction passage 31 is formed on the vehicle rear side, and is connected to the water jacket outlet 22 c so as to introduce the cooling water into the cylinder head 12 from the water jacket outlet 22 c of the cylinder block 11.

The main water jacket 32 branches from the cooling water introduction passage 31 so as to cool the intake camshaft and the exhaust camshaft, and the cylinders 21a, 21b, 21c, and 21d are arranged between the intake port portion 45 and the exhaust port portion 46. While extending in the same direction as the direction, the coolant flows from the coolant introduction passage 31 toward the water jacket outlet 32a.
The main water jacket 32 circulates through the peripheral portions of the combustion chambers 41a, 41b, 41c, 41d that have generated heat so that the peripheral portions are cooled by heat exchange.

  As shown in FIGS. 10 and 11, the sub-water jacket 33 branches from the cooling water introduction passage 31 and extends in the same direction as the main water jacket 32, and is provided in the cylinder head 12 so as to pass through the lower part of the exhaust port portion 46. It has been. The sub-water jacket 33 cools the peripheral portions of the exhaust port portions 46a, 46b, 46c, and 46d that have generated heat by heat exchange, and warms the received cooling water back to the cylinders 21a, 21b, 21c, and 21d. It also plays a role of warm-up during machine operation.

  As shown in FIGS. 9, 10 and 12, the HLA cooling jacket 34 branches from the cooling water introduction passage 31 so as to pass through the peripheral portion of a lash adjuster (HLA) (not shown) accommodated in the cylinder head 12. The cylinder head 12 is formed so as to extend in the same direction as the water jacket 32. The HLA cooling jacket 34 cools the peripheral portion of each heat generated lash adjuster (HLA) by heat exchange and distributes the received cooling water toward the radiator 20.

  As shown in FIGS. 1, 3, and 10, the circulation passage 35 is an opposite end port located on the opposite side of the branch port 33 a formed in a portion branched from the coolant introduction passage 31 of the sub-water jacket 33. The cooling water is circulated from 33 b to the water jacket 22 through the bottom bypass passage 23 of the cylinder block 11.

The upper bypass passage 36 is located at an end portion of the HLA cooling jacket 34 on the vehicle front side, and is opposed to the opposite end port 33b. The opposed end port 34a formed in the HLA cooling jacket 34 and the main water jacket 32 Are configured to communicate with each other.
Cooling water flowing through the HLA cooling jacket 34 flows through the opposed end port 34 a and the upper bypass passage 36 and flows into the main water jacket 32. The upper bypass passage 36 in the present embodiment constitutes a part of the opposed end port in the cooling water passage structure of the internal combustion engine according to the present invention.

As shown in FIGS. 1, 9, and 13, the bypass passage 37 is formed in the cylinder head 12 so as to communicate the opposite end port 33 b of the sub-water jacket 33 and the upper bypass passage 36. . The bypass passage 37 can circulate the cooling water in the sub-water jacket 33 into the main water jacket 32 through the upper bypass passage 36 even when the thermostat 17 is in the open state. It has a function of preventing the occurrence of air accumulation in the vicinity.
As shown in FIG. 9, the bypass passage 37 is located above the opposite end port 33b with respect to a vertical direction perpendicular to a flat road surface on which the vehicle 1 is placed in a state where the engine 1 is mounted on the vehicle. It is formed so as to be positioned at the position, and it is configured to prevent the occurrence of air accumulation more reliably.

As shown in FIGS. 1 and 2, the crankshaft 13 has a crankpin (not shown) provided in accordance with the number of cylinders of the engine 10, is connected to a piston through a connecting rod, and is rotated by a reciprocating motion of the piston. It is made of something known to move.
The crankshaft 13 has a journal portion, and is supported rotatably on the crankshaft support portion of the cylinder block 11 via a bearing cap and a metal bearing.

The crank pulley 14 is connected to the front end portion of the crankshaft 13 and rotates together with the crankshaft 13.
The water pump 15 includes a main body (not shown) supported by the cylinder block 11, a pulley that receives power, and an impeller that pressurizes and discharges sucked cooling water.

  The water pump 15 forcibly convects the cooling water in addition to the natural convection of the cooling water circulating in the circulation paths formed in the radiator 20, the cylinder block 11 and the cylinder head 12, respectively. And heat exchange efficiency with cooling water.

  The V-ribbed belt 16 has a concavo-convex shape in which the cross section of the contact surface is arranged with a plurality of V-shapes, and is configured to increase the transmission capability by increasing the contact area with each pulley. The V-ribbed belt 16 efficiently transmits the power of the crankshaft 13 to the pulley of the water pump 15 via the crank pulley 14.

  As shown in FIG. 14, the thermostat 17 includes a thermo housing 51 connected to the outlet 20 a of the radiator 20, a thermo element 52 accommodated in the thermo housing 51, and a seal 53.

The thermo housing 51 includes a connecting portion 51 a connected to the thermostat connecting portion 25 of the cylinder block 11 and a housing portion 51 b that houses the thermo element 52.
The connection portion 51a is formed with a communication port 51h that communicates with the bottom bypass passage 23, and cooling water flows into the thermo housing 51 from the communication port 51h. In addition, a seal 53 is attached to a portion of the connecting portion 51 a that contacts the thermostat connecting portion 25, so that the connecting portion 51 a is in close contact with the thermostat connecting portion 25.

The accommodating part 51b accommodates the thermo element 52 and branches the cooling water passage, a branch port 51d, an inlet 51e opened to allow the cooling water supplied from the outlet 20a of the radiator 20 to flow in, and the cylinder block 11 An inlet 51f opened to allow cooling water to flow from the bottom bypass passage 23 and an outlet 51g opened to allow the water pump 15 to discharge cooling water.
Therefore, the branch port 51d branches the coolant supply path into a path connected to the water pump 15 and a path connected to the bottom bypass passage 23 via the communication port 51h.

  The thermo element 52 includes an upstream frame 61 positioned at the inflow port 51e, a downstream frame 62 connected to the upstream frame 61, a valve 63 that is accommodated in the downstream frame 62 and opens and closes the inflow port 51e, and a valve 63 A heat-sensitive part 64 having a cylinder filled with wax that is fixed and fixed to expand and contract by temperature change, and a rod 65 having one end held by the upstream frame 61 and the other end accommodated in the cylinder of the heat-sensitive part 64. I have.

  Further, the thermo element 52 has a coil spring 66 whose one end abuts on the valve 63 and the other end abuts on the downstream frame 62 so as to press the valve 63 toward the upstream frame 61, and a rod connected to the heat sensitive portion 64. 67, a valve 68 that is fixed to the tip of the rod 67 and opens and closes the inlet 51f, and one end abuts on the base end of the rod 67 so that the valve 68 is pressed to the communication port 51h side of the thermo housing 51, and the other end is the valve And a coil spring 69 that abuts on 68.

The upstream frame 61 is formed with a flow hole 61a through which cooling water supplied from the outlet 20a of the radiator 20 is passed. When the valve 63 is open, the cooling water flows into the downstream frame 62 from the outlet 20a. It is supposed to be.
Further, the downstream frame 62 is formed with a flow hole 62a so that the cooling water in the downstream frame 62 flows through the flow hole 62a and is discharged from the discharge port 51g toward the water pump 15. It has become.

  Further, when the heat sensitive portion 64 reaches a predetermined temperature (for example, 80 ° C. to 90 ° C.), the wax filled therein expands against the pressing force of the coil spring 66, and the upstream frame 61 together with the valve 63. The valve 63 is configured to be in an open state.

  At this time, the rod 67 moves together with the heat sensitive portion 64, compresses the coil spring 69, and the valve 68 moves along the rod 67 by the pressing force of the coil spring 69 increased by the compression, so that the inlet 51e is closed. It is comprised so that it may become.

On the other hand, when the temperature of the heat sensitive part 64 becomes lower than a predetermined temperature, the wax filled therein contracts and moves in the direction of approaching the upstream frame 61 together with the valve 63 by the pressing force of the coil spring 66, and the valve 63 Is configured to be in a closed state.
At this time, the rod 67 is moved together with the heat sensitive portion 64, the valve 68 is moved together with the rod 67, and the inlet 51f is opened.

  The radiator 20 is connected to the main body 72 through the cooling fan 71 having a motor, a main body 72 having a radiator core, a radiator cap 73 that is attached to the main body 72 and adjusts the pressure in the main body 72, and the radiator cap 73. And a reservoir tank 74 that keeps the amount and pressure of the cooling water in an optimum state.

  The main body 72 is provided with the outlet 20a and the inlet 20b described above. Cooling water is supplied from the outlet 20a into the engine 10, and the cooling water in the engine 10 circulates in the main body 72 through the inlet 20b. It has become. The cooling water is dissipated by heat exchange in the main body 72, and the cooling water circulates between the main body 72, the outlet 20a, the engine 10, and the inlet 20b.

Next, operations of the engine 10 and the radiator 20 having the cooling water passage structure according to the present embodiment will be briefly described.
When the engine 10 is started when the temperature of the cooling water is relatively low, the temperature of the catalyst of the exhaust gas purification device connected to the engine 10 is raised at an early stage to reduce exhaust emission, and the engine 10 A so-called warm-up operation is performed to improve fuel consumption and output.
During the warm-up operation, the temperature of the cooling water is lower than the set temperature, and the thermostat 17 is in a state where the wax in the heat sensitive portion 64 is contracted.
In this case, the valve 63 of the thermostat 17 shown in FIG. 14 is closed, the cooling water inflow from the outlet 20a of the radiator 20 is blocked, and the valve 68 is opened, so that the bottom bypass passage 23, the water jacket 22 and Are communicated via the branch port 51d of the thermostat 17.

When the crankshaft 13 shown in FIG. 15 rotates in this state, the water pump 15 is driven via the crank pulley 14 and the V-ribbed belt 16.
When the water pump 15 is driven, cooling water is discharged from the water pump 15 and supplied to the water jacket portion 22a through the water jacket inlet portion 22b of the cylinder block 11, and the peripheral portions of the cylinders 21a, 21b, 21c, and 21d. Are sequentially cooled by heat exchange.

The cooling water is supplied from the water jacket outlet 22 c into the cooling water introduction passage 31 of the cylinder head 12, and further circulates through the main water jacket 32, the sub water jacket 33, and the HLA cooling jacket 34. The inside is cooled by heat exchange.
As shown in FIG. 16, the cooling water in the main water jacket 32 flows into the bottom bypass passage 23 through the upper bypass passage 36, the bypass passage 37, and the circulation passage 35 in order.

Further, the cooling water in the HLA cooling jacket 34 flows into the bottom bypass passage 23 through the bypass passage 37 and the circulation passage 35.
Thus, since the cooling water in the main water jacket 32 and the HLA cooling jacket 34 flows through the bypass passage 37, it is suppressed that air stays in the opposite end port 33b of the sub-water jacket 33 shown in FIG. Is done.

  As shown in FIG. 17, the cooling water in the bottom bypass passage 23 flows from the communication port 51h of the thermostat 17 through the inlet 51f into the branch port 51d and is discharged from the outlet 51g. 15 and 18, the air is supplied into the water jacket 22 and circulates inside the cylinder block 11 and the cylinder head 12 without passing through the radiator 20.

  When the warm-up operation of the engine 10 is finished, the operation state is shifted to a normal operation state, and the temperature of the cooling water becomes higher than a predetermined temperature, the wax in the thermosensitive portion 64 expands. At this time, as shown in FIG. 14, the valve 63 of the thermostat 17 is opened, cooling water can be introduced from the outlet 20a of the radiator 20, and the valve 68 is closed, so that the bottom bypass passage 23 and the water The distribution path to the jacket 22 is blocked.

Then, the rotation of the crankshaft 13 shown in FIG. 19 drives the water pump 15 via the crank pulley 14 and the V-ribbed belt 16.
When the water pump 15 is driven, cooling water is discharged from the water pump 15 and supplied to the water jacket portion 22a through the water jacket inlet portion 22b of the cylinder block 11, and the peripheral portions of the cylinders 21a, 21b, 21c, and 21d. Are sequentially cooled by heat exchange.

  The cooling water is supplied from the water jacket outlet 22 c into the cooling water introduction passage 31 of the cylinder head 12, and further circulates through the main water jacket 32, the sub water jacket 33, and the HLA cooling jacket 34. The inside is cooled by heat exchange.

The cooling water in the main water jacket 32 flows into the radiator 20 from the inlet 20b through the water jacket outlet 32a.
Further, as shown in FIG. 20, the cooling water in the sub water jacket 33 flows into the radiator 20 from the inlet 20b through the bypass passage 37, the upper bypass passage 36, and the water jacket outlet 32a in this order.
Further, the cooling water in the HLA cooling jacket 34 sequentially flows into the radiator 20 from the inlet 20b through the upper bypass passage 36 and the water jacket outlet 32a.

Thus, the cooling water in the sub-water jacket 33 flows through the bypass passage 37, and flows into the radiator 20 from the inlet 20b through the opposed end port 34a, the upper bypass passage 36, and the water jacket outlet portion 32a.
As a result, air is restrained from staying in the opposite end port 33b of the sub-water jacket 33 shown in FIG.

  Then, the cooling water is radiated by heat exchange in the radiator 20, and the cooling water temperature is lowered. As shown in FIG. 21, the cooling water after heat radiation flows into the downstream frame 62 of the thermostat 17 from the outlet 20a, is discharged from the discharge port 51g, flows into the water pump 15, and is pressurized. Then, as shown in FIG. 19, the water is supplied into the water jacket 22 and circulates inside the cylinder block 11 and the cylinder head 12 via the radiator 20.

  Since the cooling water passage structure constituting the engine 10 according to the present embodiment is configured as described above, the following effects are obtained.

  The cooling water passage structure constituting the engine 10 according to the present embodiment has a water jacket 22 formed in the cylinder block 11 so that the cooling water supplied from the radiator 20 flows around the cylinders 21a, 21b, 21c, 21d. A cooling water introduction passage 31 formed in the cylinder head 12 so as to introduce cooling water from the water jacket 22, and a branch from the cooling water introduction passage 31 and extending in the same direction as the arrangement direction of the cylinders 21a, 21b, 21c, 21d. In addition, a main water jacket 32 that circulates the cooling water to the radiator 20 and a sub-water jacket 33 that branches from the cooling water introduction passage 31 and distributes the cooling water are provided.

  Further, the cooling water passage structure constituting the engine 10 according to the present embodiment has an opposite end port located on the opposite side of the branch port 33a formed in a portion branched from the cooling water introduction passage 31 of the sub-water jacket 33. A circulation passage 35 for circulating cooling water from the water jacket 22 to the water jacket 22, and a bottom bypass passage 23 communicating with the circulation passage 35. The main water jacket 32 communicates with the opposite end port 33 b of the sub-water jacket 33. A bypass passage 37 is provided.

  In the bypass passage 37, the bypass passage 37 is more than the opposite end port 33 b of the sub-water jacket 33 in the vertical direction perpendicular to the flat road surface on which the engine 10 is mounted on the vehicle 1. It is formed in the cylinder head 12 so as to be positioned above.

  Further, the cooling water passage structure constituting the engine 10 according to the present embodiment is provided between the radiator 20 and the water jacket 22, and a water pump 15 that pumps the cooling water in the radiator 20 into the water jacket 22. A thermostat 17 having a communication port 51 h provided in the circulation path of the cooling water between the water pump 15 and the radiator 20 and communicating with the circulation passage 35 and the bottom bypass passage 23 is provided.

  As a result, during the warm-up operation of the engine 10, the thermostat 17 blocks the flow of cooling water from the outlet 20a of the radiator 20 into the cylinder block 11, and the bottom bypass passage 23 and the water jacket 22 are connected to the thermostat. The communication is established via the 17 branch ports 51d.

In this state, the cooling water passes through the water jacket portion 22a of the cylinder block 11 and is supplied into the cooling water introduction passage 31 of the cylinder head 12, and further into the main water jacket 32, the sub water jacket 33, and the HLA cooling jacket 34. Supplied.
Then, the cooling water in the main water jacket 32 flows into the bottom bypass passage 23 through the upper bypass passage 36, the bypass passage 37 and the circulation passage 35 in order.

  Further, the cooling water in the HLA cooling jacket 34 flows into the bottom bypass passage 23 through the bypass passage 37 and the circulation passage 35. Next, since it flows into the water pump 15 and is pressurized and supplied into the water jacket 22, it circulates inside the cylinder block 11 and the cylinder head 12 without passing through the radiator 20.

  Thus, during the warm-up operation, the cooling water in the main water jacket 32 and the HLA cooling jacket 34 flows through the bypass passage 37, so that air may stay in the opposite end port 33b of the sub-water jacket 33. It is suppressed.

  That is, in the case of the conventional cooling water passage structure, since the air passage corresponding to the bypass passage 37 in the present embodiment is not provided, the engine 10 serving as the opposite end port 33b of the sub-water jacket 33 is provided. Air stayed in the corner portion of the sub-water jacket 33 on the front side of the air and stable cooling could not be obtained. On the other hand, in the cooling water passage structure in the present embodiment, the sub water jacket 33 communicates with the main water jacket 32 by the bypass passage 37, so that the cooling water is passed through the sub water jacket 33 even during the warm-up operation. Since it circulates, the effect of eliminating the problem of air retention can be obtained.

  In particular, in the case of an engine having a so-called front-up slant that is mounted so that the front of the engine is higher than the rear, and there is no left and right slant, air tends to stay in the corner portion of the sub-water jacket 33 and stay. It was difficult to discharge air. However, in the cooling water passage structure according to the present embodiment, in addition to solving the problem of air accumulation, the cooling water flows through the side of the exhaust port portion 46, so that the heat around the exhaust port portion 46 is received. It is also possible to obtain the effect that the warm-up property is improved.

During normal operation of the engine 10, the thermostat 17 allows the cooling water to flow into the cylinder block 11 from the outlet 20 a of the radiator 20, and the flow path between the bottom bypass passage 23 and the water jacket 22 is established. It will be cut off.
Then, the cooling water is supplied to the water jacket portion 22a of the cylinder block 11, and is supplied from the water jacket outlet portion 22c into the cooling water introduction passage 31 of the cylinder head 12, and further, the main water jacket 32, the sub water jacket 33, Circulates through the HLA cooling jacket 34.

The cooling water in the main water jacket 32 flows into the radiator 20 from the inlet 20b through the water jacket outlet 32a.
Further, the cooling water in the sub-water jacket 33 sequentially flows into the radiator 20 from the inlet 20b through the bypass passage 37, the upper bypass passage 36, and the water jacket outlet 32a.
Further, the cooling water in the HLA cooling jacket 34 sequentially flows into the radiator 20 from the inlet 20b through the upper bypass passage 36 and the water jacket outlet 32a.

Thus, the cooling water in the sub-water jacket 33 flows through the bypass passage 37, and flows into the radiator 20 from the inlet 20b through the opposed end port 34a, the upper bypass passage 36, and the water jacket outlet portion 32a.
As a result, it is possible to obtain an effect that air is suppressed from staying in the opposite end port 33b of the sub-water jacket 33.

  In particular, in the case of an engine having a front-up slant and no left and right slants, the problem of air accumulation is solved as in the case of warm-up operation. In other words, the air that tends to stay in the sub-water jacket 33 is mixed with the cooling water, flows into the radiator 20 from the inlet 20b, and reaches the reservoir tank 74 through the radiator cap 73. Since this air is discharged from the radiator cap 73 and the reservoir tank 74 to the atmosphere, it does not remain inside the cylinder block 11 and the cylinder head 12.

The engine 10 of the present embodiment is configured with a so-called bottom bypass type route structure in which a thermostat 17 is disposed in a cooling water passage between the outlet 20a of the radiator 20 and the water pump 15, and the cooling water passage is opened and closed. Explained the case.
However, the cooling water passage structure of the internal combustion engine according to the present invention may be constituted by another path structure. For example, the thermostat 17 may be arranged in the cooling water passage between the inlet 20b of the radiator 20 and the main water jacket 32, and the cooling water passage may be opened and closed, so that a so-called inline bypass type route structure may be used.

In the engine 10 of the present embodiment, the case where the sub-water jacket 33 is configured with an internal structure that forms a passage in the cylinder head 12 has been described.
However, in the cooling water passage structure of the internal combustion engine according to the present invention, the sub-water jacket may be configured by another structure. For example, a first pipe is formed of a pipe having a cooling passage outside the cylinder head, one end of the pipe is connected to the cooling water passage of the cylinder head, the cooling water is supplied, and the other end is connected to the thermostat. You may make it comprise an external pipe structure which provides a connection part and the 2nd connection part connected with the main water jacket part of a cylinder head, distribute | circulates cooling water to a thermostat, and distribute | circulates also to a main water jacket.

In the engine 10 of this embodiment, the case where it comprised with the water pump 15 driven by rotation of the crankshaft 13 was demonstrated.
However, the cooling water passage structure of the internal combustion engine according to the present invention may be constituted by a water pump having another structure. For example, you may make it comprise with the electric water pump driven with an electric motor.

  As described above, the cooling water passage structure of the internal combustion engine according to the present invention can prevent air from staying in the passage through which the cooling water flows, and can provide stable cooling. The present invention has an effect that a passage structure can be provided, and is useful for a cooling water passage structure in general for an internal combustion engine of a vehicle such as an automobile.

1 vehicle 10 engine (internal combustion engine)
11 Cylinder block 12 Cylinder head 15 Water pump 17 Thermostat 20 Radiator (heat exchanger)
22 Water jacket (passage around the cylinder)
23 Bottom bypass passage (circulation passage)
31 Cooling water introduction passage 32 Main water jacket (main cooling water passage)
33 Sub-water jacket (sub cooling water passage)
33a Branch port 33b Opposite end port 34 HLA cooling jacket (opposing cooling water passage)
34a Opposite end port 35 Recirculation passage 36 Upper bypass passage (opposite end port)
37 Bypass passage (main / sub-communication passage)
51h Communication port

Claims (5)

A cylinder peripheral passage for circulating cooling water radiated by the heat exchanger around the cylinder;
A cooling water introduction passage for introducing the cooling water from the cylinder peripheral passage into a cylinder head having an exhaust port;
A main cooling water passage that branches off from the cooling water introduction passage and extends in the same direction as the arrangement direction of the cylinders, and is capable of circulating the cooling water that has cooled the cylinder head to the heat exchanger;
A sub cooling water passage branched from the cooling water introduction passage and allowing the cooling water to flow in the vicinity of the exhaust port;
A recirculation passage for recirculating the cooling water from the opposite end port located on the opposite side of the branch port formed in the portion branched from the cooling water introduction passage of the sub cooling water passage to the cylinder peripheral passage;
A cooling water passage structure for an internal combustion engine comprising:
A cooling water passage structure for an internal combustion engine, comprising: a main auxiliary communication passage for communicating the opposite end port of the auxiliary cooling water passage with the main cooling water passage.   The internal combustion engine is mounted on a vehicle, and the main auxiliary communication passage is positioned above the opposite end port of the auxiliary cooling water passage with respect to a vertical direction perpendicular to a flat road surface on which the vehicle is placed. The cooling water passage structure for an internal combustion engine according to claim 1.   Counter cooling water branched from the cooling water introduction passage and extending in the same direction as the main cooling water passage, and having opposed end ports that are formed at positions facing the opposite end port and communicate with the main cooling water passage. 3. The cooling water passage structure for an internal combustion engine according to claim 1, further comprising a passage, wherein the main auxiliary communication passage communicates with the main cooling water passage through the opposed end port.   A water pump provided between the heat exchanger and the cylinder peripheral passage, for pumping the cooling water in the heat exchanger into the cylinder peripheral passage, and between the water pump and the heat exchanger The cooling water passage structure for an internal combustion engine according to claim 1 or 2, further comprising a thermostat provided in the circulation path of the cooling water and having a communication port communicating with the circulation passage.   The internal combustion engine is mounted on a vehicle, and the opposite end port of the sub cooling water passage is positioned above the branch port with respect to a vertical direction perpendicular to a flat road surface on which the vehicle is placed. The cooling water passage structure for an internal combustion engine according to claim 1 or 2.

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