JP2008133772A - Engine cooling system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine cooling device capable of attaining early warming up of the engine and obtaining efficient cooling effect of the engine. <P>SOLUTION: The cooling device for the engine (1) includes a water pump (2); a head flow passage (6); an in-block flow passage (7) passing through the inside of a cylinder block (4) and feeding cooling water to the head flow passage (6); and a block by-passing flow passage (8) by-passing the in-block flow passage (7) and feeding the cooling water to the head flow passage (6). Further, the cooling device is provided with a first thermostat (12) for circulating the cooling water fed by the water pump (2) to the block by-passing flow passage (8) or the in-block flow passage (7). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine cooling apparatus capable of effectively warming up and cooling an engine.

  Since the engine has a problem such as a large friction when the warm-up is not completed, early warm-up is required. In particular, components having sliding portions such as cylinder bores, pistons, crankshafts, and the like are desired to complete early warm-up in order to realize efficient operation. When an in-cylinder explosion starts in a normal engine, engine components such as cylinder blocks and cylinder heads, engine oil that circulates in oil passages formed in these engine components, and cooling that circulates in a water jacket The water is warmed and warming up gradually.

  On the other hand, after the engine is warmed up, a cooling device is mounted on the engine in order to avoid an excessive increase in the temperature of each part of the engine.

  There are various types of such engine cooling devices, for example, at the time of cold start that requires warm-up, the cooling water circulation to the cylinder block is suppressed to achieve early warm-up, There has been proposed an engine cooling device configured to start circulation to the cylinder block when the warm-up is completed. As one of such engine cooling devices, there is one in which cooling water is distributed and supplied to a cylinder head and a cylinder block after the warm-up is completed. An improved version of such a so-called separation cooling system is disclosed in Patent Document 1.

JP 2004-346828 A

  By the way, in the engine equipped with the so-called separation cooling system as described above, the cooling water circulation to the cylinder block is suppressed at the cold start, and the cooling water is distributed to the cylinder block and the cylinder head after the warm-up is completed. And supply. For this reason, when a large amount of cooling water flows into the cylinder block, the flow rate of the cooling water that flows into the cylinder head and cools the cylinder head may be insufficient.

  Further, in such an engine cooling device, the cooling water circulation to the cylinder block is suppressed when the engine is cold-started. For this reason, even when the engine is started and the engine is immediately operated at a high speed, a sufficient amount of cooling water is not supplied to the cooling system of the engine, so that the inside of the engine may be excessively heated. .

  Therefore, an object of the present invention is to provide an engine cooling apparatus that can achieve early engine warm-up and can obtain an efficient engine cooling effect.

  An engine cooling apparatus of the present invention that solves such a problem includes a water pump, a head passage provided inside a cylinder head, a block bypass passage that supplies cooling water to the head passage, and a cylinder block interior. A flow path in the block for supplying cooling water to the head flow path through the flow path, and flow path switching means for circulating the cooling water supplied by the water pump to the block bypass flow path or the flow path in the block. (Claim 1). The flow path switching means in such an engine cooling device distributes the cooling water supplied by the water pump to the block bypass flow path when the engine is cold started, and after the engine is warmed up, the water pump It can be set as the 1st three-way valve which distribute | circulates the supplied cooling water to the said flow path in a block (Claim 2). Thus, the engine cooling device of the present invention has two channels for supplying cooling water to the cylinder head, and the two channels can be switched according to the warm-up state of the engine. . That is, at the time of cold start of the engine that requires active warm-up of the cylinder block, cooling water is supplied to the cylinder head through a flow path not passing through the cylinder block. At this time, since the cooling water in the cylinder block stays, the cylinder block can be warmed up early. After the engine is warmed up, cooling water is supplied to the cylinder head through the inside of the cylinder block. Thereby, the cylinder block can be cooled.

  As in the present invention, in an engine cooling device that retains cooling water in the cylinder block at the time of cold start, the cylinder block is actively used even when the engine is operated at high speed, even at the time of cold start of the engine. Cooling may be required. In preparation for such a case, the engine cooling device of the present invention is a first three-way valve that opens and closes the flow path switching unit according to temperature, and is arranged in parallel with the first three-way valve, A first differential pressure valve that opens the valve according to the discharge pressure and allows the cooling water to flow into the in-block flow path can be provided. If the flow path switching means is a first three-way valve that opens and closes according to the temperature, the cooling water in the flow path in the block can be retained during cold start. In addition, by providing the first differential pressure valve, the cooling water can be circulated to the in-block flow path prior to the temperature rise of the cooling water. That is, the discharge amount of the water pump increases in proportion to the engine speed and raises the cooling water pressure. Therefore, if the cooling water pressure reaches the valve opening pressure of the first differential pressure valve, the state of the first three-way valve is affected. First, the cooling water flows through the in-block flow path. As a result, it is possible to suppress the engine from being overheated.

  Further, such a cooling device for an engine includes a radiator flow path for flowing cooling water to the radiator, a radiator bypass flow path for bypassing the radiator and flowing cooling water, the radiator flow path, and the radiator bypass flow path. The second three-way valve disposed at the merging point and the second differential pressure valve installed in the radiator bypass flow path can be provided (claim 4). By adopting such a configuration, when the pressure is cold and the second differential pressure valve is closed, it is possible to retain the coolant including the cooling water in the head flow path. Can be achieved. In such a cooling device for an engine, the second three-way valve and the second differential pressure valve can be provided integrally (claim 5).

  Since the temperature of the cooling water after cooling the cylinder block and the cylinder head has risen, it can be used as a heat source for a heater for the vehicle interior. Further, even the cooling water after cooling the cylinder block and the cylinder head can be used for cooling other devices. Therefore, the engine cooling device of the present invention is provided in a heat exchange device flow path in which a heat exchange device for exchanging heat with the cooling water flowing through the head flow channel is disposed, and in the heat exchange device flow path. And a heat sensitive valve (claim 6). Here, the heat exchange device includes both a device for the purpose of raising the temperature by cooling water and a device for the purpose of cooling. The heat sensitive valve controls the flow of cooling water to the heat exchange device flow path in which these heat exchange devices are arranged. With this heat sensitive valve, when the cooling water temperature is lower than a certain temperature, the inflow of the cooling water into the heat exchange device channel can be blocked. As a result, the amount of heat lost in the heat exchange device flow path can be suppressed, and the cylinder block can be warmed up quickly. Such a heat-sensitive valve can be disposed regardless of upstream or downstream of the heat exchange device on the heat exchange device flow path. However, if a heat sensitive valve is arranged downstream of the heat exchange device, the heat exchange device is exposed to high-pressure cooling water. Therefore, considering the pressure resistance of the heat exchange device, the heat sensitive valve is located upstream of the heat exchange device. It is desirable to arrange on the side.

  According to the engine cooling device of the present invention, the flow of the head flow path, the block bypass flow path and the block internal flow path for supplying cooling water to the head flow path, and the block bypass flow path and the block internal flow path Since the road switching means is provided, early engine warm-up can be achieved, and an efficient engine cooling effect can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view schematically showing a flow path of cooling water in the engine 1 of the first embodiment. The engine 1 includes a water pump 2 that is driven by the rotation of a crankshaft (not shown), a cylinder head 3 and a cylinder block 4. A head flow path 6 through which cooling water flows is provided inside the cylinder head 3.

  Further, the engine 1 passes through the inside of the cylinder block 4 to supply cooling water to the head flow path 6 and bypasses the block internal flow path 7 to cool the head flow path 6. A block bypass passage 8 for supplying water is provided. The block bypass flow path 8 supplies cooling water directly to the head flow path 6 without passing through the inside of the cylinder block 4. The in-block flow path 7 is a so-called water jacket, and is not only a flow path for flowing cooling water to the head flow path 6 but also cools the cylinder block 4. The in-block channel 7 and the head channel 6 are communicated with each other through a water hole 9. Such an in-block flow path 7 has a larger volume than the block bypass flow path 8. Therefore, when cooling water is supplied to the head flow path 6 via the intra-block flow path 7, a large amount of cooling water can be circulated to the head flow path 6.

  An oil cooler flow path 10 provided with an oil cooler 11 branches off from the in-block flow path 7. The oil cooler flow path 10 joins a first flow path 19 that is a flow path between a radiator 15 and a second thermostat 17 described later.

  In addition, although the block bypass flow path 8 in a present Example is set as the structure which does not pass the inside of the cylinder block 4, it can also be comprised so that a part of block bypass flow path 8 may pass the inside of the cylinder block 4. FIG. .

  The cooling water discharged from the water pump 2 flows into the in-block flow path 7 and the block bypass flow path 8 as described above, and the flow path switching means (first three-way valve) according to the present invention is at the branch point. ) Corresponding to the first thermostat 12 is provided. The first thermostat 12 will be described in detail with reference to FIG. The first thermostat 12 includes a first connection port 12a on the water pump 2 side, a second connection port 12b on the in-block channel 7 side, and a third connection port 12c on the block bypass channel 8 side. FIG. 2A shows a state in which the cooling water temperature is T1 ° C. or less which is the operation start temperature of the first thermostat 12 and the first connection port 12a and the third connection port 12c communicate with each other. . FIG. 2B shows a state where the cooling water temperature reaches T1 ° C. and the first connection port 12a and the second connection port 12b communicate with each other. That is, the cooling water discharged from the water pump 2 flows through the block bypass flow path 8 when the cooling water temperature is equal to or lower than T1 ° C., and flows to the block internal flow path 7 when the cooling water temperature reaches T 1 ° C. Begin to. In addition, when the 1st thermostat 12 will be in the state shown in FIG.2 (b), the cooling water discharged from the water pump 2 will distribute | circulate almost all the amount to the flow path 7 in a block, but 1st thermostat 12 In the transition time region in which the state shown in FIG. 2A shifts to the state shown in FIG. 2B, the cooling water may flow through both the intra-block flow path 7 and the block bypass flow path 8.

  Between the water pump 2 of the engine 1 and the in-block flow path 7, it is arranged in parallel with such a block thermo 12, and opens according to the discharge pressure of the water pump 2 to the in-block flow path 7. A first differential pressure valve 14 for allowing cooling water to flow in is provided. The first differential pressure valve 14 can circulate the cooling water discharged from the water pump 2 to the in-block flow path 7 without depending on the cooling water temperature. That is, if the first differential pressure valve 14 is opened, the cooling water can be circulated to the in-block flow path 7 even when the cooling water temperature does not reach T1 ° C. Such a first differential pressure valve 14 is disposed in a flow path connecting the discharge port 2a of the water pump 2 and the flow path 7 in the block, and the discharge pressure of the water pump 2 becomes high, so that the flow path 7 in the block. The valve is opened when a certain pressure difference occurs between the internal pressure and the internal pressure. In this embodiment, the engine 1 is tuned to open at the discharge pressure when the rotational speed of the engine 1 reaches approximately 4000 rpm.

  On the upstream side of the water pump 2, a radiator 15 and a reserve tank 16 connected by a reserve tank channel 18 are disposed. A second thermostat 17 corresponding to the second three-way valve of the present invention is disposed between the radiator 15 and the radiator 15. The radiator 15 and the second thermostat 17 are connected by a first flow path 19, and the second thermostat 17 and the water pump 2 are connected by a second flow path 20. The reserve tank 16 and the water pump 2 are connected by a third flow path 34. Here, the 1st flow path 19 forms the radiator flow path in this invention with the 7th flow path 36 mentioned later.

  Here, the second thermostat 17 will be described in detail with reference to FIG. The second thermostat 17 is disposed at the junction of the first flow path 19 and a radiator bypass flow path 27 to be described later. The second thermostat 17 distributes the cooling water after flowing through the head flow path 6 to the radiator 15 or the radiator. 15 is switched to bypass. The second thermostat 17 includes a first connection port 17a on the first flow channel 19 side, a second connection port 17b on the second flow channel 20 side, and a third connection port 17c on the radiator bypass flow channel 27 side. . FIG. 3A shows a state in which the cooling water temperature is T2 ° C. or less which is the operation start temperature of the second thermostat 17 and the second connection port 17b and the third connection port 12c communicate with each other. . FIG. 3B shows a state where the cooling water temperature reaches T2 ° C. and the first connection port 17a and the second connection port 17b communicate with each other. That is, the cooling water after flowing through the head flow path 6 flows through the radiator bypass flow path 27 side when the cooling water temperature is T2 ° C. or lower, and when the cooling water temperature reaches T2 ° C., That is, distribution to the radiator 15 starts.

  As described above, the cooling water flowing through the radiator 15 or the radiator bypass flow path 27 is the cooling water after flowing through the head flow path 6. The cooling water after flowing through the head flow path 6 is divided into three flow paths, a fourth flow path 22, a fifth flow path 23, and a sixth flow path 24 at the first branch point 21 downstream of the head outlet 6a. Branch to Hereinafter, these three flow paths will be described.

  The fourth flow path 22 is further branched at the second branch point 25 into two flow paths, a heater flow path 28 and a cooler flow path 29. A heater 31 is disposed in the heater flow path 28, and an EGR cooler 32 is disposed in the cooler flow path 29. The heater flow path 28 is provided with a heater valve 30 made of bimetal upstream of the heater 31 and corresponding to the thermal valve in the present invention. The heater flow path 28 and the cooler flow path 29 are merged at the first merge point 33 and then merged into the second flow path 20 that connects the water pump 2 and the second thermostat 17. The heater 31 and the EGR cooler 32 both correspond to the heat exchange device of the present invention, and the heater channel 28 and the cooler channel 29 both correspond to the heat exchange device channel of the present invention.

  A turbocharger (T / C) 26 is disposed in the fifth flow path 23, and the downstream side thereof joins the first flow path 19 that connects the radiator 15 and the second thermostat 17.

  The sixth flow path 24 further branches at the third branch point 35 into the seventh flow path 36 and the radiator bypass flow path 27 described above. The seventh flow path 36 is connected to the radiator 15 as described above, and constitutes the radiator flow path in the present invention together with the first flow path 19. On the other hand, the radiator bypass channel 27 is connected to the third connection port 17c of the second thermostat 17 as described above.

  In the cooling device for the engine 1 configured as described above, since the first thermostat 12 changes the flow path according to the cooling water temperature, the engine 1 is cold-started when the cooling water temperature of the engine 1 is T1 ° C. or less. A different flow path is formed by the flow path of the cooling water at the time and the flow path of the cooling water after the warm-up when the cooling water temperature of the engine 1 reaches T1 ° C.

  Then, the flow path of the cooling water at the time of the cold start of the engine 1 will be described, and then the flow path of the cooling water after the engine 1 is warmed up will be described. Here, the cold start time is a time when the cylinder block 4 of the engine 1 needs to be warmed up, the cooling water temperature of the engine 1 is T1 ° C. or less, and the first thermostat 12 is shown in FIG. It points to the case where it becomes a state. On the other hand, after warm-up is a time when the cylinder block 4 of the engine 1 needs to be actively cooled, the cooling water temperature reaches T1 ° C., and the first thermostat 12 is in the state shown in FIG. It points to after becoming.

  FIG. 4 is an explanatory view showing the flow path of the cooling water flowing through the engine 1 during the cold start. In FIG. 4, a flow path through which cooling water flows during cold start is indicated by a solid line, and a flow path through which cooling water does not flow (flow path where cooling water stays) is indicated by a broken line. When the engine 1 is cold started, since the cooling water temperature is T1 ° C. or lower, the first thermostat 12 distributes the cooling water supplied from the water pump 2 to the block bypass passage 8. By the way, the temperature T2 ° C. at which the flow path of the second thermostat 17 is switched is substantially equal to the temperature T1 ° C. at which the flow path of the first thermostat 12 is switched. For this reason, at the time of cold start, the second thermostat 17 distributes the cooling water from the radiator bypass path 27 to the second flow path 20.

  In the engine 1 at the time of cold start in which such a flow path is formed, the cooling water pumped from the water pump 2 flows into the head flow path 6 through the first thermostat 12 and through the block bypass path 8. . The cooling water that has flowed into the head flow path 6 cools the cylinder head 3. Thereafter, the cooling water flowing through the head flow path 6 flows out from the head outlet 6 a toward the first branch point 21. The cooling water flowing into the first branch point 21 is divided into the fourth flow path 22 and the sixth flow path 24. In addition, at the time of cold start, since the 1st connection port 17a of the thermostat 17 is in the closed state, the cooling water does not distribute | circulate through the 1st flow path 19. For this reason, the cooling water cannot flow out at the outlet of the fifth flow path 23, and the cooling water hardly flows into the fifth flow path 23 from the first branch point 21 and stays there.

  The cooling water flowing into the fourth flow path 22 from the first branch point 21 is divided into the heater flow path 28 and the cooler flow path 29 at the second branch point 25. The cooling water flowing into the cooler flow path 29 cools the EGR cooler 32 and then flows out toward the first junction 33. On the other hand, the flow state of the cooling water to the heater flow path 28 differs depending on the open / closed state of the heater valve 30 provided in the heater flow path 28. The heater valve 30 is closed when the cooling water temperature is T3 ° C. or lower, and the flow of the cooling water is shut off. For this reason, when the cooling water temperature is lower than T3 ° C., the cooling water in the heater flow path 28 stays. When the warm-up progresses and the cooling water temperature reaches T3 ° C., the heater valve 30 opens and the cooling water flows into the heater 31. The heater 31 is warmed by the cooling water and can supply warm air into the vehicle. The cooling water that has flowed through the heater flow path 28 thus flows out toward the first merge point 33 and merges with the cooling water flowing out from the cooler flow path 29. The cooling water flowing out of the heater flow path 28 and the cooler flow path 29 flows toward the second flow path 20 after merging at the first merging point 33. Thereafter, the water pump 2 feeds the engine 1 again.

  On the other hand, the cooling water flowing into the sixth flow path 24 from the first branch point 21 flows into the radiator bypass path 27 from the third branch point 35. The cooling water flowing into the radiator bypass path 27 flows out to the flow path 20 via the thermostat 17. Thereafter, the cooling water is sent out again into the engine 1 by the water pump 2. In addition, at the time of cold start, since the 1st connection port 17a of the thermostat 17 is the closed state, the cooling water in the radiator 15 cannot flow out. For this reason, the cooling water in the radiator 15 and the seventh flow path 36 stays.

  As described above, when the engine 1 is cold started, cooling water is supplied to the head flow path 6 in the cylinder head 3 through the block bypass path 8 that does not pass through the cylinder block 4. As a result, the cylinder head 3 is cooled, and the cylinder block 4 in which the cooling water stays is warmed up early. Further, since the cooling water of the radiator 15 stays, the temperature rise of the cooling water is not hindered. Further, when the cooling water temperature is equal to or lower than T3 ° C., the heater valve 30 is closed and the flow of the cooling water to the heater flow path 28 is blocked. Can be suppressed. Thereby, the temperature increase of the cooling water is not hindered, and the engine 1 can be warmed up early.

  Even at such a cold start, when the engine 1 rotates at a high speed of 4000 rpm or higher, the first differential pressure valve 14 is opened, and the cooling water flows into the in-block flow path 7. Thereby, it is avoided that the engine 1 becomes high temperature rapidly.

  Next, the flow path of the cooling water after the engine 1 is warmed up will be described. As the warm-up proceeds and the temperature in the engine 1 rises, the coolant temperature of the engine 1 also rises accordingly. When the cooling water temperature reaches T1 ° C., the first thermostat 12 is operated and the flow path of the cooling water is switched. The second thermostat 17 that operates at a temperature T2 ° C. that is substantially equal to the temperature T1 ° C. also switches the flow path of the cooling water.

  FIG. 5 is an explanatory view showing a flow path of the cooling water flowing through the engine 1 after warming up. In FIG. 5, the flow paths that are in circulation are indicated by solid lines, and the non-circulation flow paths are indicated by broken lines. After the engine 1 is warmed up, the cooling water temperature has reached T1 ° C., so the first thermostat 12 circulates the cooling water supplied from the water pump 2 to the in-block flow path 7. In addition, after warming up, the second thermostat 17 causes the cooling water to flow from the first flow path 19 to the second flow path 20.

  In the engine 1 after warm-up in which such a flow path is formed, the cooling water pumped from the water pump 2 flows into the head flow path 6 through the in-block flow path 7 via the first thermostat 12. At this time, the cooling water cools the cylinder block 4. Most of the cooling water flowing through the in-block flow path 7 flows into the head flow path 6 in the cylinder head 3 through the water holes 9 provided in the cylinder block 4 and cools the cylinder head 3. A part of the cooling water in the intra-block path 7 flows into the flow path 10. The cooling water flowing into the flow path 10 cools the oil cooler 11 and then flows into the first flow path 19.

  Thereafter, the cooling water flowing through the head flow path 6 flows out from the head outlet 6 a toward the first branch point 21. The cooling water branches and flows out to the fourth flow path 22, the fifth flow path 23 and the sixth flow path 24 at the first branch point 21. Thus, the cooling water flows through the fifth flow path 23 after the engine 1 is warmed up. This is because the first connection port 17a of the second thermostat 17 is open, and the cooling water is flowing through the first flow path 19, so that the fifth flow path 23 is accompanied by the cooling water flowing through the first flow path 19. This is because the cooling water flows. At this time, since the third connection port 17c of the second thermostat 17 is closed, the cooling water in the bypass passage 27 remains.

  Since the flow of the cooling water diverted from the first branch point 21 and flowing into the fourth flow path 22 is almost the same as that at the time of cold start, detailed description thereof is omitted here. However, since the heater valve 30 is always open at the temperature of the cooling water after warming up, the cooling water flows through the heater flow path 28, and hot air can be supplied into the vehicle.

  On the other hand, the cooling water that has flowed into the fifth flow path 23 from the first branch point 21 flows into the vicinity of the turbocharger 26, cools the turbocharger 26, joins the first flow path 19, and again passes through the engine 1. Circulate.

  The cooling water that has flowed into the sixth flow path 24 from the first branch point 21 flows into the radiator 15. The cooling water flowing into the radiator 15 is cooled and flows into the second thermostat 17 through the first flow path 19. Thereafter, the water is supplied to the water pump 2 through the second flow path 20 and is sent out again into the engine 1. A part of the cooling water in the radiator 15 is supplied to the reserve tank 16 and stored in the reserve tank 16. The cooling water in the reserve tank 16 is supplied to the water pump 2 through the third flow path 34 to the water pump 2 as necessary.

  In this way, in the engine 1 after warm-up, a cooling water flow path for supplying cooling water to the cylinder head 3 via the cylinder block 4 is formed. For this reason, it is possible to supply the cooling water to the cylinder block 4 that requires active cooling and other parts that require cooling, thereby cooling the part. Moreover, since the cooling water which circulated through each part of the engine 1 and heated up is cooled through the radiator 15, it is possible to suppress an excessive increase in the cooling water temperature.

  Thus, the engine 1 of the present embodiment has two flow paths, that is, a cooling water path at the time of cold start and a cooling water path after warm-up. The flow paths of the two systems are switched according to the warm-up state of the engine 1 using the first thermostat 12 and the second thermostat 17. That is, when the purpose is to warm up the cylinder block 4 at the cold start, the cooling water can be supplied to the cylinder head 3 without cooling the cylinder block 4. Moreover, since the cooling water of the radiator 15 stays, it is possible to suppress an increase in the temperature due to the cooling water, and the temperature inside the engine 1 can be raised rapidly. In this way, the warm-up of the engine 1 is made efficient to achieve early warm-up. On the other hand, the warmed-up engine 1 supplies cooling water to the cylinder head 3 via the cylinder block 4, and can also cool the cylinder block 4 together with the cylinder head 3. Further, since the cooling water flows to the radiator 15 and is cooled, the cooling water maintains an appropriate cooling effect. In this way, the engine 1 after warm-up can be cooled, and overheating of the engine 1 can be suppressed.

  Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 6 is an explanatory view showing the flow path of the cooling water of the engine 40 of the second embodiment. The engine 40 of the second embodiment has almost the same configuration as the engine 1 of the first embodiment, but differs in the following points. That is, in the second embodiment, in place of the heater valve 30 disposed in the heater passage 28 in the first embodiment, the second is located upstream of the second branch point 25 where the heater flow path 28 and the cooler flow path 29 branch. The heat sensitive valve 37 is arranged in the four flow paths 22. The thermal valve 37 is opened when the cooling water temperature reaches T3 ° C. In the engine 40 configured as described above, the cooling water downstream of the thermal valve 37 stays until the cooling water temperature reaches T3 ° C. Thereby, when the cooling water temperature is T3 ° C. or lower, heat exchange between the heater 31 and the EGR cooler 32 is not performed, and the loss of heat quantity of the cooling water in the heater flow path 28 and the cooler flow path 29 is suppressed. As a result, the cooling water temperature can be increased quickly. In addition, since the other structure is the same as Example 1, about the component same as Example 1, the same reference number is attached | subjected in drawing and the detailed description is abbreviate | omitted.

  Next, Embodiment 3 of the present invention will be described with reference to the drawings. FIG. 7 is an explanatory view showing the flow path of the cooling water of the engine 50 of the third embodiment. The engine 50 of the third embodiment has substantially the same configuration as the engine 1 of the first embodiment, but the third embodiment is different from the first embodiment in that a second differential pressure valve 38 is provided in the radiator bypass passage 27. It is different.

  The second differential pressure valve 38 is configured to open when the upstream water pressure is higher than the downstream water pressure by a certain level or more, and close otherwise. By disposing such a second differential pressure valve 38, it is possible to regulate the circulation of the cooling water circulating in the engine 50 at the time of cold start. That is, when the second differential pressure valve 38 is closed, the cooling water in the sixth flow path 24 also stays. For this reason, circulation of the cooling water in the engine 50 is restricted, and the engine 50 is warmed up early. On the other hand, when the second differential pressure valve 38 is opened, the cooling water flows to the second thermostat 17. In addition, since the other structure is the same as Example 1, about the component same as Example 1, the same reference number is attached | subjected in drawing and the detailed description is abbreviate | omitted.

  Next, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 8 is an explanatory view showing the flow path of the cooling water of the engine 60 of the fourth embodiment. The engine 60 of the fourth embodiment has substantially the same configuration as the engine 50 of the third embodiment, but instead of the second thermostat 17 and the second differential pressure valve 38 provided in the engine 50 in the third embodiment, the embodiment 60 4 differs from the third embodiment in that a third thermostat 39 is provided.

  The third thermostat 39 is obtained by integrating the second thermostat 17 and the second differential pressure valve 38 corresponding to the second three-way valve in the present invention. The third thermostat 39 will be described in detail with reference to FIG. The third thermostat 39 is connected to the first connection port 39a on the first flow channel 19 side, the second connection port 39b on the second flow channel 20 side, the third connection port 39c on the radiator bypass flow channel 27 side, and the bottom of the pellet 39d. A connected differential pressure valve 39e is provided. FIG. 9A shows the third state when the cooling water temperature is T2 ° C. or lower, which is the operation start temperature of the third thermostat 39, and the pressure of the radiator bypass passage 27 is lower than the opening pressure of the differential pressure valve 39e. The state of the thermostat 39 is shown. In this state, none of the connection ports in the third thermostat 39 are in communication, and cooling water is not circulating. FIG. 9B shows a state of the third thermostat 39 when the cooling water temperature is T2 ° C. or lower, but the pressure of the radiator bypass passage 27 is equal to or higher than the opening pressure of the differential pressure valve 39e. In the third thermostat 39 in this state, the second connection port 39 b and the third connection port 39 c communicate with each other, and the cooling water flows from the radiator bypass channel 27 to the second channel 20. FIG. 9C shows a state when the cooling water temperature reaches T2 ° C. In the third thermostat 39 in this state, the first connection port 39a and the second connection port 39b communicate with each other, and the cooling water flows from the first channel 19 to the second channel 20. At this time, the differential pressure valve 39e is pressed against the third connection port 39c as the pellet 39d moves, and closes the third connection port 39c. For this reason, the inflow of the cooling water from the radiator bypass channel 27 is blocked.

  By providing such a third thermostat 39, it is possible to obtain the same effect as that of the third embodiment. In addition, since the other structure is the same as Example 3, about the same component as Example 3, the same reference number is attached | subjected in drawing and the detailed description is abbreviate | omitted.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope.

It is explanatory drawing which showed the flow path of the cooling water of the engine of Example 1. FIG. It is explanatory drawing which showed the 1st thermostat of Example 1, (a) is a figure which shows a mode that a 1st connection port and a 3rd connection port are connecting, (b) is a 1st connection port and a 2nd connection. It is a figure which shows a mode that the opening | mouth communicates. It is explanatory drawing which showed the 2nd thermostat of Example 1, (a) is a figure which shows a mode that a 3rd connection port and a 2nd connection port are connecting, (b) is a 1st connection port and a 2nd connection. It is a figure which shows a mode that the opening | mouth communicates. It is explanatory drawing which showed the flow path of the cooling water at the time of the cold start of the engine of Example 1. FIG. It is explanatory drawing which showed the flow path of the cooling water after the engine warm-up of Example 1. FIG. It is explanatory drawing which showed the flow path of the cooling water of the engine of Example 2. FIG. It is explanatory drawing which showed the flow path of the cooling water of the engine of Example 3. FIG. It is explanatory drawing which showed the flow path of the cooling water of the engine of Example 4. FIG. It is explanatory drawing which showed the 3rd thermostat of Example 4, (a) is a figure which shows a mode that neither connection port is connecting, (b) is a 3rd connection port and a 2nd connection port communicating. The figure which shows a mode that (c) shows the state which the 1st connection port and the 2nd connection port are connecting.

Explanation of symbols

1, 40, 50, 60 Engine 2 Water pump 3 Cylinder head 4 Cylinder block 6 Head flow path 7 Block internal flow path 8 Block bypass flow path 12 First thermostat 14 First differential pressure valve 15 Radiator 17 Second thermostat 19 First flow path 20 Second flow path 21 First branch point 22 Fourth flow path 23 Fifth flow path 24 Sixth flow path 25 Second branch point 27 Radiator bypass flow path 28 Heater flow path 29 Cooler flow path 30 Heater valve 33 First merge Point 34 Third flow path 35 Third branch point 36 Seventh flow path 37 Thermal valve 38 Second differential pressure valve 39 Third thermostat

Claims (6)

A water pump,
A head flow path provided inside the cylinder head;
A block bypass channel for supplying cooling water to the head channel;
An in-block flow path for supplying cooling water to the head flow path through the inside of the cylinder block;
Channel switching means for circulating the cooling water supplied by the water pump to the block bypass channel or the channel in the block;
An engine cooling system comprising: The engine cooling device according to claim 1,
The flow path switching means is
The cooling water supplied by the water pump is circulated to the block bypass passage when the engine is cold started, and the cooling water supplied by the water pump is circulated to the passage in the block after the engine is warmed up. Engine cooling device characterized by being a three-way valve. The engine cooling device according to claim 1,
As the first three-way valve that opens and closes the flow path switching means according to the temperature,
An engine comprising a first differential pressure valve that is arranged in parallel with the first three-way valve, opens according to the discharge pressure of the water pump, and allows cooling water to flow into the flow path in the block. Cooling system. The engine cooling device according to claim 1,
A radiator flow path for circulating cooling water to the radiator;
A radiator bypass passage for bypassing the radiator and circulating cooling water;
A second three-way valve disposed at a confluence of the radiator flow path and the radiator bypass flow path;
A second differential pressure valve installed in the radiator bypass flow path;
An engine cooling system comprising: The engine cooling device according to claim 4.
The engine cooling apparatus, wherein the second three-way valve and the second differential pressure valve are integrally provided. The engine cooling device according to claim 1,
A heat exchanging device flow path in which a heat exchanging device for exchanging heat with the cooling water flowing through the head flow path is disposed;
A thermal valve disposed in the heat exchange device flow path;
An engine cooling system comprising:

Images