JP2011202634A - Cooling device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling device for an internal combustion engine, capable of suppressing great deformation of a cylinder bore wall resulting from a reduction in the flow amount of cooling water flowing in a body passage of the engine body during warming up the engine.SOLUTION: A cooling water passage 40 of the cooling device 20 for the internal combustion engine 1 includes a first circulation circuit 61 for circulation between each of a first water path 41 and a second water path 42 of the engine body 10 and a water pump 23, and a second circulation circuit 62 for circulation between a third water path 43 passing through bore-bore passages 16A-16C and the water pump 23. During warming up the engine, the flow amount of cooling water being circulated in the first circulation circuit 61 is set smaller than the flow amount of the cooling water being circulated in the first circulation circuit 61 after warming up the engine, and cooling water is circulated in the second circulation circuit 62.

Description

  The present invention relates to a cooling device for an internal combustion engine including a circulation circuit for circulating cooling water through an engine body.

  As the above cooling device, Patent Document 1 describes a device that stops the circulation of cooling water circulating in the engine body when the engine is warmed up. As a result, the warm-up of the internal combustion engine is promoted.

JP 2008-169750 A

By the way, when the circulation of the cooling water in the engine body is stopped when the engine is warmed up, the cylinder bore wall may be thermally deformed due to an increase in the temperature of the cylinder bore.
The present invention has been made in view of the above circumstances, and the object of the present invention is to provide a large cylinder bore wall due to the reduced flow rate of the cooling water flowing through the main body passage of the engine main body when the engine is warmed up. An object of the present invention is to provide a cooling device for an internal combustion engine that can suppress deformation.

In the following, means for achieving the above object and its effects are described.
(1) The invention according to claim 1 is a cooling apparatus for an internal combustion engine including a circulation circuit for circulating cooling water through the engine body, wherein the circulation circuit includes a body passage provided in the engine body. A first circulation circuit for circulating the cooling water through the second circulation circuit for circulating the cooling water through the passage between the bores provided between the cylinder bores of the engine body and without passing through the body passage. The cooling device includes the flow rate of the cooling water in the first circulation circuit when the engine is warmed up as a flow rate X1, and the flow rate of the cooling water in the first circulation circuit after the engine is warmed up as the flow rate X2. The gist is to circulate cooling water in the second circulation circuit when X1 is made smaller than the flow rate X2 and the flow rate X1 is made smaller than the flow rate X2 during engine warm-up.

  According to this invention, since the flow rate X1 is made smaller than the flow rate X2, warming up of the internal combustion engine is promoted. Further, since the cooling water in the second circulation circuit is circulated when the flow rate X1 is smaller than the flow rate X2, the space between the cylinder bores is cooled by the cooling water. That is, it is possible to suppress the cylinder bore wall from being largely deformed due to the reduced flow rate of the cooling water flowing through the main body passage of the engine main body when the engine is warmed up.

  (2) The invention according to claim 2 is the cooling apparatus for an internal combustion engine according to claim 1, wherein the second circulation circuit is arranged not to pass through the radiator and the passage between the bores, but through the main body passage. A circulation circuit A for circulating the coolant and a circulation circuit B for circulating cooling water through the passage between the bores and without passing through the main body passage and the radiator, and the cooling device uses the flow rate X1 as the flow rate X2. In this case, the cooling water in the circulation circuit A is circulated and the circulation of the cooling water in the circulation circuit B is stopped.

  According to this invention, when the flow rate X1 is smaller than the flow rate X2, the cooling water in the circulation circuit A is circulated and the circulation of the cooling water in the circulation circuit B is stopped. Therefore, the cooling water cooled by the radiator is Supplied to the passage between bores.

  (3) The invention according to claim 3 is the cooling device for an internal combustion engine according to claim 1 or 2, wherein the cooling device is in two warm-up states with different warm-up levels with respect to the warm-up completion state. Regarding the first warm-up state and the second warm-up state, the relatively low temperature range of the coolant is defined as the first warm-up state, and the relatively high temperature range of the coolant is defined as the second warm-up state. In the first warm-up state, the flow rate X1 is made smaller than the flow rate X2, and the cooling water in the second circulation circuit is circulated. In the second warm-up state, the flow rate X1 is changed to the first flow rate X1. The gist is that the flow rate X1 is larger than that in the warm-up state.

  According to the present invention, in the first warm-up state, the flow rate X1 is made smaller than the flow rate X2, and the cooling water in the second circulation circuit is circulated, so that the warm-up of the internal combustion engine is promoted and cooling that flows through the main body passage It can suppress that a big deformation | transformation arises in a cylinder bore wall resulting from the flow volume of water being reduced. Moreover, the cooling water which flows through a main body channel | path increases by making the flow volume X1 in a 2nd warm-up state larger than the flow volume X1 in a 1st warm-up state.

  (4) The invention according to claim 4 is the cooling device for the internal combustion engine according to claim 3, wherein the first circulation circuit circulates the cooling water through the main body passage and not through the radiator. C and a circulation circuit D that circulates the cooling water through the main body passage and the radiator, and the cooling device circulates the cooling water of the circulation circuit C in the second warm-up state and the circulation circuit D. The main point is to stop the circulation of the cooling water.

  In the present invention, in order to circulate the cooling water in the circulation circuit C and stop the circulation of the cooling water in the circulation circuit D in the second warm-up state, the cooling water supplied to the main body passage bypasses the radiator. Therefore, warming up of the internal combustion engine 1 can be promoted as compared with the case where the cooling water of the circulation circuit D is supplied to the main body passage.

  (5) The invention according to claim 5 is the cooling apparatus for an internal combustion engine according to claim 3 or 4, wherein the second circulation circuit passes through the radiator and the passage between the bores and without passing through the body passage. A circulation circuit A for circulating the cooling water and a circulation circuit B for circulating the cooling water through the inter-bore passage and not through the main body passage and the radiator are included. The gist is to circulate the cooling water in the circulation circuit B in the warm-up state and stop the circulation of the cooling water in the circulation circuit A.

  In the present invention, since the cooling water in the circulation circuit B is circulated and the circulation of the cooling water in the circulation circuit A is stopped in the second warm-up state, the cooling water supplied between the cylinder bores bypasses the radiator.

  (6) The invention according to claim 6 is the cooling apparatus for an internal combustion engine according to any one of claims 1 to 5, wherein the second circulation circuit is interposed between the radiator and the passage between the bores and the main body. A circulation circuit A for circulating the cooling water without passing through the passage, and a circulation circuit B for circulating the cooling water through the passage between the bores and without passing through the main body passage and the radiator. The gist of the apparatus is to circulate the cooling water in the circulation circuit A and stop the circulation of the cooling water in the circulation circuit B after the warm-up is completed.

  In this invention, after the warm-up is completed, the cooling water in the circulation circuit A is circulated and the circulation of the cooling water in the circulation circuit B is stopped, so that the cooling water supplied between the cylinder bores is cooled via the radiator. Become.

  (7) The invention according to claim 7 is the cooling apparatus for an internal combustion engine according to any one of claims 1 to 6, wherein a part of the second circulation circuit is provided on an outer wall of the engine body. Is the gist.

  According to this invention, a part of the second circulation circuit is provided on the outer wall of the engine body, whereby a part of the second circulation circuit is cooled by the traveling wind when the vehicle is traveling. Thereby, the temperature rise of a cylinder bore can be suppressed further.

  (8) The invention according to claim 8 is the cooling apparatus for an internal combustion engine according to any one of claims 1 to 7, wherein the inter-bore passage is provided on an upper end side of the wall portion between the cylinder bores. The main point is that

  The cylinder bore has the highest temperature at its upper end. Therefore, the upper end portion of the cylinder bore is most easily thermally deformed. In that respect, in the present invention, the passage between the bores is provided on the upper end side of the wall portion between the cylinder bores, so that the temperature rise of the cylinder bores can be effectively suppressed.

  (9) The invention according to claim 9 is the cooling apparatus for an internal combustion engine according to any one of claims 1 to 8, wherein the engine body includes a first cylinder and a second cylinder arranged in a row, and The second circulation circuit includes a first inter-bore passage as the inter-bore passage provided between the first cylinder and the second cylinder, the second cylinder, and the second cylinder. A second inter-bore passage as the inter-bore passage provided between the third cylinder, one end of the first inter-bore passage extending in the cylinder arrangement direction, and one end of the second inter-bore passage; And a second connection passage extending in the cylinder arrangement direction and connecting the other end of the first bore passage and the other end of the second bore passage to each other. It is summarized as including.

  (10) The invention according to claim 10 is the internal combustion engine cooling device according to any one of claims 1 to 9, wherein the circulation circuit is provided with a pump for circulating cooling water, The gist of the invention is that an electromagnetic valve for opening or closing the circulation circuit is provided between the pump and the engine body in the first circulation circuit.

The schematic diagram which shows typically the structure of an internal combustion engine provided with the apparatus about the cooling device of the internal combustion engine of this invention. Regarding the internal combustion engine of the same embodiment, (a) is a schematic diagram schematically showing the flow of cooling water immediately after engine startup, (b) is a schematic diagram schematically showing the flow of cooling water during warm-up, (c) ) Is a schematic diagram schematically showing the flow of cooling water after engine warm-up. (A) is a top view which shows the planar structure of a cylinder block, (b) is sectional drawing which shows the cross-sectional structure which follows the cross-sectional line AA of (a) about the engine main body of the embodiment. The flowchart which shows the procedure about the "cooling water distribution process" performed by the electronic control apparatus of the embodiment. The time chart which shows an example of the execution aspect of "cooling water distribution processing" about the cooling device of the embodiment.

An embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, an internal combustion engine 1 includes an engine body 10 including a cylinder block 11 and a cylinder head 12, a cooling device 20 that cools the engine body 10 by circulating cooling water, and cooling water for the cooling device 20. And a control device 30 for controlling the flow of the.

  The cylinder block 11 is provided with a plurality of cylinder bores 13A to 13D (see FIG. 3A) and a water jacket 14 that surrounds a part of the bores 13A to 13D from the outside. Pistons 15 (see FIG. 3B) are respectively provided in the cylinder bores 13A to 13D. Between the cylinder bores 13A and 13B, between the cylinder bores 13B and 13C, and between the cylinder bores 13C and 13D, on the cylinder bore wall (wall portion), passages 16A to 16C between the bores through which cooling water flows (see FIG. 3A). ) Are provided.

  The cooling device 20 includes a cooling water passage 40 that circulates cooling water between the engine body 10, a radiator 21 that performs heat exchange between the outside air and the cooling water, and a flow rate of the cooling water that flows into the radiator 21. An electric thermostat 22 to be controlled and a water pump 23 for discharging cooling water toward the engine body 10 are provided. The “flow rate” is the volume (l / min) or mass (g / min) of cooling water that passes through a predetermined passage section per unit time.

The cooling water passage 40 includes the following first water passage 41 to sixth water passage 46.
The first water channel 41 connects the respective inlets of the water jacket 14 and the cylinder head 12 and the outlet of the water pump 23 to each other. The second water passage 42 connects the respective outlets of the water jacket 14 and the cylinder head 12 and the inlet of the electric thermostat 22 to each other. The third water passage 43 connects the intermediate portion of the first water passage 41 and the inlet of the electric thermostat 22 to each other via the bore passages 16A to 16C. The fourth water channel 44 connects the outlet of the electric thermostat 22 and the inlet of the radiator 21 to each other. The fifth water channel 45 connects the outlet of the radiator 21 and the inlet of the water pump 23 to each other. The sixth water passage 46 connects the outlet of the electric thermostat 22 and the inlet of the water pump 23 to each other.

  In the first water channel 41, a first electromagnetic valve 51 that opens or closes the water channel 41 is provided on the downstream side of the branch portion between the water channel 41 and the third water channel 43. The second water channel 42 is provided with a second electromagnetic valve 52 that opens or closes the water channel 42.

  In the cooling water passage 40, a first water passage 41, a second water passage 42, a fourth water passage 44, and a fifth water passage are provided as circulation circuits for circulating the cooling water through the water jacket 14 and not through the inter-bore passages 16 </ b> A to 16 </ b> C. The first circulation circuit 61 is formed by the 45 and the sixth water passage 46. Further, as a circulation circuit for circulating the cooling water through the inter-bore passages 16 </ b> A to 16 </ b> C and not through the water jacket 14, a portion of the first water passage 41 upstream of the first electromagnetic valve 51, the third water passage 43, and the first water passage 43. A second circulation circuit 62 is formed by the four water channels 44, the fifth water channel 45, and the sixth water channel 46.

  The water pump 23 sucks and discharges cooling water by the rotation of the impeller connected to the crankshaft of the engine body 10. That is, since the rotational speed of the impeller of the water pump 23 increases as the engine rotational speed increases, the amount of cooling water discharged from the water pump 23 increases as the engine rotational speed increases.

  The electric thermostat 22 changes the communication state between the second water channel 42 and the third water channel 43, the fourth water channel 44 and the sixth water channel 46. That is, when the operation state of the electric thermostat 22 is the first switching state, the second water channel 42, the third water channel 43, and the fourth water channel 44 are communicated with each other, and the second water channel 42, the third water channel 43, and the sixth water channel are communicated. 46 is cut off. When the operation state of the electric thermostat 22 is the second switching state, the second water channel 42, the third water channel 43, and the sixth water channel 46 are communicated with each other, and the second water channel 42, the third water channel 43, and the fourth water channel are communicated. 44 is cut off.

  The control device 30 includes an electronic control device 31 that performs various controls including control of each device of the engine body 10, the electric thermostat 22, the first electromagnetic valve 51, and the second electromagnetic valve 52, and a cooling water temperature sensor 32. And various sensors. The cooling water temperature sensor 32 outputs a signal corresponding to the temperature of the cooling water flowing through the first water channel 41 near the outlet of the water pump 23 to the electronic control device 31.

  By the way, from the viewpoint of completing the engine warm-up at an early stage, the degree of cooling of the engine body 10 by the cooling water is small before the engine warm-up is completed, that is, it passes through the water jacket 14 and the cylinder head 12 of the engine body 10 respectively. It is desirable that the flow rate of cooling water to be reduced.

  On the other hand, between the cylinder bores, heat generated by combustion is likely to be trapped as compared with other portions of the cylinder block 11, and thus thermal deformation is likely to occur. Accordingly, even when the flow rate of the cooling water passing through the water jacket 14 and the cylinder head 12 is reduced, it is desirable that the flow rate of the cooling water passing between the cylinder bores (the passages 16A to 16C between the bores) is large.

  The electronic control device 31 performs distribution control for controlling the flow of the cooling water flowing in the cooling water passage 40 as control for satisfying the above-described requirements. In the distribution control, the opening degree of each of the first electromagnetic valve 51 and the second electromagnetic valve 52 is changed based on the temperature of the cooling water in the cooling water passage 40 (hereinafter referred to as “cooling water temperature THW”) and the electric thermostat. By changing the operation state 22, the cooling water circulation mode of the cooling water passage 40 is switched to any one of the following first circulation mode to third circulation mode.

  In the first circulation mode, both the first electromagnetic valve 51 and the second electromagnetic valve 52 are maintained in the closed state, and the electric thermostat 22 is maintained in the first switching state. As a result, the first circulation circuit 61 is closed and the second circulation circuit 62 is opened in a form including the radiator 21 in the distribution path.

  In the second circulation mode, both the first electromagnetic valve 51 and the second electromagnetic valve 52 are maintained in the open state, and the electric thermostat 22 is maintained in the second switching state. Thereby, both the 1st circulation circuit 61 and the 2nd circulation circuit 62 are open | released in the form which does not include the radiator 21 in a distribution path.

  In the third circulation mode, both the first solenoid valve 51 and the second solenoid valve 52 are maintained in the open state, and the electric thermostat 22 is maintained in the first switching state. Thereby, both the 1st circulation circuit 61 and the 2nd circulation circuit 62 are open | released in the form which includes the radiator 21 in a distribution path.

With reference to FIG. 2, the flow of the cooling water in each circulation mode will be described.
As shown in FIG. 2A, in the first circulation mode, the cooling water in the first circulation circuit 61 and the second circulation circuit 62 flows as follows. That is, the cooling water does not circulate in the first circulation circuit 61. In the second circulation circuit 62, the cooling water discharged from the water pump 23 flows into the electric thermostat 22 through the third water channel 43 and the fourth water channel 44. Then, the cooling water that has flowed out of the electric thermostat 22 flows again into the water pump 23 through the fifth water passage 45, the radiator 21, and the sixth water passage 46.

  As shown in FIG. 2B, in the second circulation mode, the cooling water in the first circulation circuit 61 and the second circulation circuit 62 flows as follows. That is, in the first circulation circuit 61, the cooling water discharged from the water pump 23 flows into the electric thermostat 22 through the first water channel 41 and the second water channel 42. Then, the cooling water flowing out from the electric thermostat 22 passes through the sixth water passage 46, that is, bypasses the radiator 21 and flows into the water pump 23 again. On the other hand, in the second circulation circuit 62, the cooling water discharged from the water pump 23 flows into the electric thermostat 22 through the third water channel 43. And the cooling water which flowed out from the electric thermostat 22 bypasses the radiator 21, and flows in into the water pump 23 again.

  As shown in FIG.2 (c), in the 3rd circulation mode, the cooling water in the 1st circulation circuit 61 and the 2nd circulation circuit 62 distribute | circulates as follows. That is, in the first circulation circuit 61, the cooling water discharged from the water pump 23 flows into the electric thermostat 22 through the first water channel 41 and the second water channel 42. Then, the cooling water flowing out from the electric thermostat 22 flows into the water pump 23 again via the radiator 21. Here, the circulation mode of the cooling water in the first water channel 41 and the second water channel 42 is the same as in the second circulation mode. That is, the opening degree of the first solenoid valve 51 and the second solenoid valve 52 is the same as the opening degree in the second circulation mode. On the other hand, in the second circulation circuit 62, the cooling water discharged from the water pump 23 flows into the electric thermostat 22 through the third water channel 43 and the fourth water channel 44. Then, the cooling water flowing out from the electric thermostat 22 flows into the water pump 23 again via the radiator 21.

  With reference to FIG. 3, details of the configuration of the engine body 10 and the configuration of the third water channel 43 will be described. In FIG. 3, the radiator 21 and the electric thermostat 22 are omitted.

  As shown in FIG. 3A, the cylinder block 11 has four cylinder bores 13A to 13D arranged in order from the front in the front-rear direction. Between the cylinder bores 13A and 13B, between the cylinder bores 13B and 13C, and between the cylinder bores 13C and 13D, there are respectively provided bore passages 16A to 16C penetrating between the cylinder bores in the left-right direction, which is a direction orthogonal to the cylinder arrangement direction. Yes. Branch pipes 43C to 43E each having a space as a water channel are inserted into each of the inter-bore passages 16A to 16C.

  On the outer wall of the cylinder block 11, an upstream main pipe 43A that connects one end (right side) of each branch pipe 43C to 43E and the other (left side) end of each branch pipe 43C to 43E are connected to each other. A downstream main pipe 43B to be connected is provided. A third water channel 43 is formed by the space in the upstream main pipe 43A, the spaces in the branch pipes 43C to 43E, and the space in the downstream main pipe 43B.

  The upstream end of the upstream main pipe 43A is connected to the outlet of the water pump 23 via the first water channel 41 (see FIG. 1). The downstream end of the downstream main pipe 43B is connected to the inlet of the water pump 23 via the fifth water channel 45 or the sixth water channel 46 (see FIG. 1).

  As shown in FIG. 3B, the inter-bore passage 16B (branch pipe 43D) is provided between the cylinder bores corresponding to the upper end portions of the cylinder block 11, that is, the upper end portions of the cylinder bores 13B and 13C. Similarly, the inter-bore passage 16A (branch pipe 43C) and the inter-bore passage 16C (branch pipe 43E) are respectively provided between the cylinder bores corresponding to the upper ends of the cylinder bores 13A and 13B and the cylinder bores 13C and 13D. The inter-bore passages 16A to 16C (branch pipes 43C to 43E) and the water jacket 14 are independent of each other, that is, directly between the bore passages 16A to 16C (branch pipes 43C to 43E) and the water jacket 14. It is provided so that cooling water does not circulate.

The cooling water flows through the third water channel 43 as follows.
The cooling water discharged from the water pump 23 flows into the branch pipes 43C to 43E from the upstream main pipe 43A. The cooling water in each branch pipe 43C-43E cools between each cylinder bore by distribute | circulating between each cylinder bore. The cooling water that has flowed out of the branch pipes 43C to 43E flows into the downstream main pipe 43B and is then sucked into the water pump 23 again.

  With reference to FIG. 4, the content of the “cooling water distribution process” that defines a specific process procedure for distribution control will be described. This process is repeatedly performed at predetermined calculation cycles when the electronic control unit 31 is operating.

  In step S10, it is determined whether or not the coolant temperature THW is equal to or higher than the first reference temperature TX. The first reference temperature TX is the coolant temperature THW at which the coolant temperature THW at that time is lower than the coolant temperature THW corresponding to the completion of engine warm-up and the circulation of the coolant in the first circulation circuit 61 is allowed to stop. As a value for determining whether or not, it is set in advance through a test or the like.

  When it is determined in step S10 that the coolant temperature THW is lower than the first reference temperature TX, in step S20, the first electromagnetic valve 51 and the second electromagnetic valve 52 are closed and the electric thermostat 22 is switched to the first switching state. Thereby, the circulation of the cooling water in the first water channel 41 and the second water channel 42 is blocked. Thereby, the circulation mode of the cooling water in the cooling water passage 40 is the first circulation mode shown in FIG.

  When it is determined in step S10 that the coolant temperature THW is equal to or higher than the first reference temperature TX, it is determined in step S30 whether the coolant temperature THW is equal to or higher than the second reference temperature TY. The second reference temperature TY is a value for determining whether or not the engine warm-up has been completed, that is, a temperature higher than the first reference temperature TX, and the coolant temperature at the completion of the engine warm-up of the engine body 10. The corresponding value is set in advance through a test or the like.

  When it is determined in step S30 that the coolant temperature THW is lower than the second reference temperature TY, that is, when it is determined that the engine is warming up, the electric thermostat 22 is switched to the second switching state in step S40. Thereby, the circulation mode of the cooling water in the cooling water passage 40 becomes the second circulation mode shown in FIG.

  When it is determined in step S30 that the coolant temperature THW is equal to or higher than the second reference temperature TY, that is, when it is determined that the engine warm-up is completed, the electric thermostat 22 is switched to the first switching state in step S50. Thereby, the circulation mode of the cooling water in the cooling water passage 40 becomes the third circulation mode shown in FIG.

With reference to FIG. 5, an example of the execution aspect of a cooling water distribution process is demonstrated.
At time t0, that is, when the operation of the internal combustion engine 1 is started, both the first electromagnetic valve 51 and the second electromagnetic valve 52 are maintained in the closed state and the electric thermostat 22 is maintained in the first switching state. Thereby, the circulation mode of the cooling water in the cooling water passage 40 is maintained in the first circulation mode.

  At time t1, that is, when the coolant temperature THW reaches the first reference temperature TX, both the first solenoid valve 51 and the second solenoid valve 52 are opened, and the operating state of the electric thermostat 22 is changed from the first switching state to the first switching state. 2 is changed to the switching state. Thereby, the circulation mode of the cooling water in the cooling water passage 40 is switched from the first circulation mode to the second circulation mode.

  After the time t2, that is, after the coolant temperature THW reaches the second reference temperature TY, the degree of increase in the coolant temperature THW decreases. After time t2, both the first solenoid valve 51 and the second solenoid valve 52 are maintained in the open state, and the electric thermostat 22 is maintained in the first switching state. Thereby, the circulation mode of the cooling water in the cooling water passage 40 is maintained in the third circulation mode.

According to the present embodiment, the following effects can be achieved.
(1) In the present embodiment, control is performed so that the cooling water does not circulate in the first water channel 41 and the second water channel 42 when the cooling water in the cooling water passage 40 falls below the first reference temperature TX by flow control. Therefore, the engine body 10 can be prevented from being cooled by the cooling water having a low temperature. Thereby, warming up of the internal combustion engine 1 is promoted. Further, since the cooling water circulates in the third water passage 43 when the cooling water in the cooling water passage 40 falls below the first reference temperature TX, the space between the cylinder bores is cooled by the cooling water. That is, it is possible to prevent the cylinder bore wall from being greatly deformed due to the fact that the cooling water in the first water passage 41 and the second water passage 42 does not circulate when the engine is warmed up.

  (2) In the present embodiment, when the cooling water temperature THW is lower than the first reference temperature TX, the cooling water flow mode in the cooling water passage 40 becomes the first circulation mode, so that the radiator 21 is provided between the cylinder bores. The cooled cooling water is supplied by. Thereby, the temperature rise between cylinder bores can be suppressed further.

  (3) In this embodiment, when the cooling water temperature THW is lower than the second reference temperature TY, the cooling water circulation mode in the cooling water passage 40 is the second circulation mode, so that the cooling water bypassing the radiator 21 is provided. Can be suppressed from being supplied to the water jacket 14 and the cylinder head 12, respectively. As a result, warm-up promotion of the internal combustion engine 1 can be effectively achieved.

  (4) In the present embodiment, since the third water channel 43 is provided on the outer wall of the engine body 10, the outer surface of the engine body 10 is a radiator as shown by an arrow Y1 (see FIG. 3A) when the vehicle is traveling. It is cooled by the traveling wind that has passed through 21. Thereby, since the upstream main pipe 43A and the branch pipes 43C to 43E other than the part inserted into the inter-bore passages 16A to 16C and the downstream main pipe 43B are provided on the outer surface of the engine body 10, the traveling wind It is cooled by. As a result, the temperature rise of the cylinder bores 13A to 13D can be suppressed.

  (5) The cylinder bores 13A to 13D have the highest temperature at their upper ends. Therefore, the upper end portions of the cylinder bores 13A to 13D are most easily thermally deformed. In this respect, in the present embodiment, by providing the bore passages 16A to 16C (branch pipes 43C to 43E) on the upper end side of the cylinder bore wall, it is possible to effectively suppress the temperature rise of the cylinder bores 13A to 13D.

  (6) When the engine body 10 is in a high temperature state, the cylinder bores 13A to 13D undergo thermal deformation so that the respective inner diameters are expanded. Here, in the cylinder bores 13B and 13C, the inner diameter in the front-rear direction is reduced by the thermal deformation of the cylinder bores 13A and 13D. On the other hand, the cylinder bores 13B and 13C are thermally deformed in the left-right direction. Thereby, since the outer peripheral surface of the piston 15 and the inner peripheral surface in the front-rear direction of the cylinder bores 13B, 13C are close to each other, the piston 15 collides with the cylinder bores 13B, 13C. As a result, piston hitting sound is generated.

  In this respect, in the present embodiment, since the cooling water circulates in the inter-bore passages 16A to 16C (branch pipes 43C to 43E), the inner diameter of the cylinder bores 13B and 13C due to thermal deformation of the cylinder bores 13A and 13D is suppressed. Can do. As a result, since the collision between the cylinder bores 13B and 13C and the pistons 15 accommodated in the bores 13B and 13C can be suppressed, generation of piston hitting sound can be suppressed.

  (7) According to the present embodiment, the cooling water in the third water channel 43 is circulated over the engine operation period after the engine is started, so that control of a dedicated solenoid valve or pump can be omitted. Therefore, it is possible to promote warm-up of the internal combustion engine 1 and suppress thermal deformation of the cylinder bores 13A to 13D with a simple configuration.

  (8) In the present embodiment, the first electromagnetic valve 51 is provided downstream of the water pump 23 and upstream of the cylinder block 11 or the cylinder head 12. Therefore, it is possible to prevent the high-temperature cooling water from flowing backward from the cylinder block 11 or the cylinder head 12 to the water pump 23.

  (9) According to the present embodiment, the first electromagnetic valve 51 is provided on the upstream side of the branch portion between the water channel supplied to the water jacket 14 and the water channel supplied to the cylinder head 12 in the first water channel 41 (FIG. 1). (Reference) The flow rate of supplying cooling water to the water jacket 14 and the cylinder head 12 can be controlled by one first electromagnetic valve 51.

(Other embodiments)
The specific configuration of the cooling device for an internal combustion engine of the present invention is not limited to the configuration exemplified in the above embodiment, and can be changed as follows, for example. The following modifications are not applied only to the above-described embodiment, and different modifications can be combined with each other.

  In the above embodiment, the inter-bore passages 16A to 16C (branch pipes 43C to 43E) are provided between the three cylinder bores, but the inter-bore passages 16A to 16C (branch pipes 43C to 43E) are at least one between the cylinder bores. Can also be provided.

  In the above embodiment, the first electromagnetic valve 51 is provided in the first water passage 41 and the second electromagnetic valve 52 is provided in the second water passage 42. However, one of the first electromagnetic valve 51 and the second electromagnetic valve 52 is connected. It can be omitted.

  In the above embodiment, the electric thermostat 22 is set to the first switching state when the cooling water temperature THW is lower than the first reference temperature TX in the cooling water circulation process, but the electric thermostat 22 may be set to the second switching state. .

  In the above embodiment, the inter-bore passages 16A to 16C (branch pipes 43C to 43E) are provided on the upper end side of the cylinder wall, but the inter-bore passages 16A to 16C (branch pipes 43C to 43E) are positioned in the vertical direction. It is not limited to this. For example, it can be provided at the center or lower end side of the cylinder bore wall.

  In the above embodiment, the engine body 10 is arranged so that the arrangement direction of the cylinder bores 13A to 13D is the same direction as the vehicle traveling direction, but the direction in which the cylinder bores of the engine body are orthogonal to the vehicle traveling direction. It can also arrange so that.

In the above embodiment, the third water channel 43 is configured to be attached to the outside of the engine body 10, but the third water channel 43 can also be provided inside the engine body 10.
In the above embodiment, a mechanical water pump connected to the crankshaft is used as the water pump 23, but an electric water pump that is not connected to the crankshaft may be used as the water pump 23. In this case, the water pump can also be driven on condition that the ignition switch of the internal combustion engine 1 is switched from the off state to the on state.

In the case of using an electric water pump, the following control is also possible.
・ Stop driving the water pump for a period of the engine operation period.
・ Limit the flow rate of cooling water discharged from the water pump.

  In the above embodiment, the electric thermostat 22 has two switching states, the first switching state and the second switching state, but the switching state of the electric thermostat 22 is not limited to this. For example, the electric thermostat 22 can distribute cooling water to both the fourth water channel 44 and the sixth water channel 46. In this case, for example, in the first circulation mode and the third circulation mode, the switching state of the electric thermostat 22 so as to increase the flow rate of the cooling water in the fourth water channel 44 rather than the flow rate of the cooling water in the sixth water channel 46 ( The opening degree can also be changed. Further, for example, in the second circulation mode, the switching state (opening degree) of the electric thermostat 22 is changed so as to increase the flow rate of the cooling water in the sixth water channel 46 rather than the flow rate of the cooling water in the fourth water channel 44. You can also.

  In the above embodiment, in the first circulation mode, the first solenoid valve 51 and the second solenoid valve 52 are closed, but the opening degrees of the first solenoid valve 51 and the second solenoid valve 52 are the same. There is no limit.

  For example, a small amount of cooling water can be circulated through the first water channel 41 and the second water channel 42. Thereby, compared with the case where the 1st solenoid valve 51 and the 2nd solenoid valve 52 maintain a full open state at the time of a 1st circulation mode, warming-up promotion can be aimed at.

  Further, for example, in the first circulation mode, the first electromagnetic valve 51 and the second electromagnetic valve 52 can be fully opened over a certain period. This certain period is a period in which warm-up promotion is not hindered excessively.

  In the above embodiment, the cooling device for the internal combustion engine is applied to the gasoline engine, but it can also be applied to a diesel engine.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 10 ... Engine main body, 11 ... Cylinder block, 12 ... Cylinder head, 13, 13A-13D ... Cylinder bore, 14 ... Water jacket, 15 ... Piston, 16A-16C ... Passage between bores, 20 ... Cooling device, DESCRIPTION OF SYMBOLS 21 ... Radiator, 22 ... Electric thermostat, 23 ... Water pump (pump), 30 ... Control device, 31 ... Electronic control device, 32 ... Cooling water temperature sensor, 40 ... Cooling water channel (circulation circuit), 41 ... First water channel (Main body passage), 42 ... second water passage (main body passage), 43 ... third water passage, 43A ... upstream main water passage (first connection passage), 43B ... downstream main pipe (second connection passage), 43C to 43E ... Branch pipe 44 ... 4th water channel 45 ... 5th water channel 46 ... 6th water channel 51 ... 1st solenoid valve 52 ... 2nd solenoid valve 61 ... 1st circulation path 62 ... 2nd circulation path

Claims (10)

In the cooling device for an internal combustion engine including a circulation circuit for circulating cooling water through the engine body,
The circulation circuit includes a first circulation circuit for circulating cooling water through a main body passage provided in the engine main body, an inter-bore passage provided between cylinder bores of the engine main body, and the main body passage. A second circulation circuit for circulating the cooling water without intervening,
The cooling device is configured such that the flow rate of the cooling water in the first circulation circuit when the engine is warmed is the flow rate X1, the flow rate of the cooling water in the first circulation circuit after the engine is warmed is the flow rate X2, and the flow rate X1 is A cooling device for an internal combustion engine, wherein the cooling water is circulated in the second circulation circuit when the flow rate X1 is smaller than the flow rate X2 while the engine is warmed up. . The cooling apparatus for an internal combustion engine according to claim 1,
The second circulation circuit includes a circulation circuit A for circulating cooling water through the radiator and the inter-bore passage and not through the main body passage, and the main passage and the radiator through the inter-bore passage. And a circulation circuit B for circulating the cooling water without any
The cooling device circulates the cooling water in the circulation circuit A and stops the circulation of the cooling water in the circulation circuit B when the flow rate X1 is smaller than the flow rate X2. Cooling system. The cooling device for an internal combustion engine according to claim 1 or 2,
In the cooling device, the first warm-up state and the second warm-up state, which are two warm-up states having different warm-up levels with respect to the warm-up completion state, are set to the first in which the temperature range of the coolant is relatively low. The warming-up state is set, the higher temperature range of the cooling water is set as the second warming-up state, the flow rate X1 is made smaller than the flow rate X2 in the first warming-up state, and the second circulation circuit Cooling water is circulated, and in the second warm-up state, the flow rate X1 is larger than the flow rate X1 in the first warm-up state. The cooling apparatus for an internal combustion engine according to claim 3,
The first circulation circuit includes a circulation circuit C that circulates cooling water through the main body passage and without a radiator, and a circulation circuit D that circulates cooling water through the main body passage and the radiator,
The cooling device for an internal combustion engine, which circulates the cooling water in the circulation circuit C and stops the circulation of the cooling water in the circulation circuit D in the second warm-up state. The cooling apparatus for an internal combustion engine according to claim 3 or 4,
The second circulation circuit includes a circulation circuit A for circulating cooling water through the radiator and the inter-bore passage and not through the main body passage, and the main passage and the radiator through the inter-bore passage. Including a circulation circuit B for circulating cooling water without
The cooling device for an internal combustion engine, wherein the cooling water in the circulation circuit B is circulated in the second warm-up state and the circulation of the cooling water in the circulation circuit A is stopped. In the cooling device of the internal combustion engine according to any one of claims 1 to 5,
The second circulation circuit includes a circulation circuit A for circulating cooling water through the radiator and the inter-bore passage and not through the main body passage, and the main passage and the radiator through the inter-bore passage. And a circulation circuit B for circulating cooling water without
The cooling device of the internal combustion engine, wherein the cooling water of the circulation circuit A is circulated after the warm-up is completed and the circulation of the cooling water of the circulation circuit B is stopped. The internal combustion engine cooling device according to any one of claims 1 to 6,
A cooling device for an internal combustion engine, wherein a part of the second circulation circuit is provided on an outer wall of the engine body. The internal combustion engine cooling device according to any one of claims 1 to 7,
The cooling system for an internal combustion engine, wherein the inter-bore passage is provided on an upper end side of a wall portion between the cylinder bores. The internal combustion engine cooling device according to any one of claims 1 to 8,
The engine body includes a first cylinder, a second cylinder, and a third cylinder arranged in a row,
The second circulation circuit is provided between a first inter-bore passage as a passage between the bores provided between the first cylinder and the second cylinder, and between the second cylinder and the third cylinder. A second inter-bore passage as the inter-bore passage, and a first connection that extends in the cylinder arrangement direction and connects one end of the first inter-bore passage and one end of the second inter-bore passage to each other An internal combustion engine comprising a passage and a second connection passage extending in a cylinder arrangement direction and connecting the other end of the first bore passage and the other end of the second bore passage to each other. Engine cooling system. The cooling apparatus for an internal combustion engine according to any one of claims 1 to 9,
The circulation circuit is provided with a pump for circulating the cooling water,
A cooling device for an internal combustion engine, wherein an electromagnetic valve for opening or closing the circulation circuit is provided between the pump and the engine body in the first circulation circuit.

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