JP4352882B2 - Engine cooling system - Google Patents

Description

  The present invention allows cooling water to pass through the water jacket of the engine body, and allows the cooling water after passing to flow into a heat dissipating path having a radiator for cooling the engine or a short-circuit path for promoting warm air, and depending on the cooling water temperature. In particular, the present invention relates to an engine cooling apparatus that branches into water jackets of a cylinder block and a cylinder head that form an engine body and supplies cooling water. .

  When the engine is in a low temperature operating range, the engine cooling device flows cooling water discharged from the water pump into the water jacket in the engine body, returns it to the water pump suction path through the short circuit from the outlet, and does not release heat. In the operating area after the warm-up is completed, the cooling water from the water jacket in the engine body is circulated from the outlet to the heat dissipation path with the radiator and then returned to the water pump suction path. Switching is performed. In this way, the engine cooling device suppresses the engine body warming promotion and excessive temperature rise after warming up, and a thermostat equipped with a temperature-sensitive or electromagnetic switching valve is used to switch the flow here. Has been.

  For example, in the engine cooling apparatus 100 shown in FIG. 9, the cooling water from the water pump 110 is branched and branched into the cylinder block 120 and the cylinder head 130. The cooling water flowing into the cylinder block 120 can flow from the downstream outlet 140 of the cylinder block to one radiator circulation path Rr1 including the thermostat B and the radiator 150, and the cooling water flowing into the cylinder head 130 is supplied from the upstream outlet 160 of the cylinder head. It can flow through the inflow chamber 170 of the thermostat A to the other radiator circulation path Rr2. Here, a part of the cooling water flowing into the cylinder block 120 is formed so as to flow into the cylinder head 130 side through a plurality of branch paths Ru according to the operating state.

  The thermostat A includes an outflow chamber 190 between the inflow chamber 170 and the return chamber 180 to which the cooling water from the radiator circulation paths Rr1 and Rr2 returns. The outflow chamber 190 communicates with the suction path Re of the water pump 110. The outflow chamber 190 accommodates a switching valve 200 having a temperature sensing unit (not shown). When the cooling water is below a predetermined temperature, the switching valve 200 causes the inflow chamber 170 and the outflow chamber 190 to communicate with each other and shuts off the return chamber 180 and the outflow chamber 190, so that only the cooling water on the cylinder head 130 side is directly passed. Returning to the suction path Re side, warming up can be promoted during this time. Further, the switching valve 200 causes the return chamber 180 and the outflow chamber 190 to communicate with each other and shuts off the inflow chamber 170 and the outflow chamber 190 when the cooling water reaches a predetermined temperature or higher, so that the cooling water on the cylinder head 130 side is supplied by the radiator 150. After cooling by heat radiation, the water pump 110 is returned to the water pump 110. Further, in the operating region where the thermostat B is opened, the cooling water of the cylinder block 120 is guided to the radiator 150 to be cooled.

The engine cooling apparatus 100 provided with such a branch cooling system exhibits cooling characteristics as shown in FIG.
Here, at the time of warming up (when the radiator circulation paths Rr1, Rr2 are shut off) and at the closing timing of the thermostat B after warming up, the total flow rate Qt returning from the outflow chamber 190 of the thermostat A to the water pump 110 (when the C / B valve is closed) The total flow) is equal to the cylinder head outlet flow (qh1). After the warm-up, when the thermostat B is opened, the sum (qh2 + qb) of the cylinder head outlet flow rate qh2 and the cylinder block outlet flow rate qb becomes the total flow rate Qt (total flow rate when the C / B valve is opened) returning to the water pump 110. .

  In this case, the total flow rate Qt (C / B valve closing total flow rate) returning to the water pump 110 when the thermostat B is closed during warm-up and after warm-up, and the total flow rate Qt (C / B valve opening total flow) is not significantly changed, but when looking at the cylinder head outlet flow, qh1 when C / B is closed and qh2 when C / B is opened (<qh1) It is clear that the amount of cooling water in the cylinder head after warming-up decreases.

  In JP-A-10-82320 (Patent Document 1), the total flow rate of the cooling water flowing through each of the cylinder head and the cylinder block is adjusted by opening and closing the electric main thermostat, that is, when the thermostat is closed, a bypass is used. Cooling water is supplied to a heater or oil cooler side, and in the disclosure, cooling water is supplied to the radiator side to perform heat dissipation cooling, and the amount of cooling water flowing to the cylinder block is increased or decreased by an electric sub-thermostat to adjust the temperature of the engine body. We are trying to achieve fine cooling water control that responds to changes.

JP-A-10-82320

In the engine cooling device 100 shown in FIG. 9, it is clear that the amount of cooling water in the cylinder head after warm-up decreases as described above, and such a change in the flow rate of cooling water on the cylinder head side is disclosed in Patent Document 1. This also occurs when the sub thermostat is opened.
In this way, when the flow rate of the cooling water flowing through the cylinder head 130 suddenly changes D (qh2 from qh1) when the thermostat B or the like that controls the flow of cooling water in the cylinder block 120 is opened, the cooling performance of the cylinder head 130 decreases rapidly. It is conceivable that the cooling of the cylinder head at the time of high rotation and high load becomes insufficient and excessive temperature rise is caused.

Therefore, in order to cope with this, it is conceivable that the inner diameter of the outlet of the cylinder block is formed in advance so as to reduce the amount of cooling water flowing into the cylinder head. Insufficient cooling water in the cylinder block at the time of load will result in excessive temperature rise.
The present invention has been made to meet the above-described circumstances, and provides an engine cooling device capable of promoting warm-up of an engine and preventing excessive temperature rise of a cylinder head and a cylinder block at the time of high engine speed and high load. The purpose is to provide.

  According to a first aspect of the present invention, there is provided an engine cooling apparatus comprising: a cylinder block cooling path that introduces a part of a discharge flow of a water pump into a cylinder block and leads the first discharge outlet; A cylinder head cooling path that flows into the head and leads to the second outlet, and a discharge chamber that communicates with the cooling water suction path of the water pump and accommodates a temperature-sensitive switching valve, and the cooling water temperature is equal to or lower than a predetermined temperature. And a thermostat for switching operation so as to guide the cooling water from the second outflow port to the discharge chamber, and when the cooling water temperature exceeds a predetermined temperature, the cooling water from the second outflow port is guided to the discharge chamber through the radiator, and And a cylinder block cooling water discharge passage for guiding cooling water from the first outlet to the discharge chamber.

  According to a second aspect of the present invention, in the engine cooling device according to the first aspect, a branch flow in which the branch cooling water from the cylinder block cooling path is introduced into the cylinder head cooling path at the overlapping portion of the cylinder block and the cylinder head. The introduction hole is formed.

  A third aspect of the present invention is the engine cooling device according to the first or second aspect, wherein the thermostat includes a first chamber into which the cooling water from the second outlet flows and the radiator is interposed between the discharge chamber and the radiator. And a second chamber into which the cooling water flows in. When the cooling water temperature is equal to or lower than a predetermined temperature, the cooling water in the first chamber is caused to flow into the discharge chamber, and when the cooling water temperature exceeds the predetermined temperature, the cooling water in the second chamber is The temperature-sensitive switching valve is switched so as to flow into the discharge chamber.

  According to a fourth aspect of the present invention, in the engine cooling device according to the first, second, or third aspect, the flow path diameter of the cylinder block cooling water discharge path is smaller than the flow path diameter of the short circuit path between the first chamber and the discharge chamber. It was set as follows.

  According to the first aspect of the present invention, the cylinder block cooling water from the first outlet is always returned to the cooling water suction passage of the water pump via the cylinder block cooling water discharge passage, through the discharge chamber of the thermostat, When the cooling water temperature is equal to or lower than the predetermined temperature by the thermostat, the cooling water from the cylinder head cooling path is led directly from the second outlet to the discharge chamber, and when the cooling water temperature exceeds the predetermined temperature, the cooling water from the cylinder head cooling path is guided. Therefore, the flow rate of the cooling water passing through the cylinder block does not change greatly due to the switching of the thermostat, and the cooling of the cylinder block can be accurately performed, and the amount of cooling water passing through the cylinder head can be reduced. The reduction in the cooling performance of the cylinder head due to a lack of cooling water can be stably avoided without greatly changing. Furthermore, since the cooling water that passes through the cylinder block always passes through the discharge chamber that houses the temperature-sensitive switching valve, the change in the temperature of the cooling water that passes through the cylinder block can be reflected in the switching of the thermostat. Road-specific thermostats can be eliminated and costs can be reduced.

  According to the second aspect of the present invention, it is possible to increase / decrease the amount of the branch cooling water flowing from the cylinder block cooling path into the cylinder head cooling path by forming the branch flow introducing hole. Even if the cooling water flow rate of the cylinder block is suppressed by the throttling action, the cooling water flows through the branch flow introduction hole, so that the cooling efficiency of the cylinder block at the time of high rotation and high load can be increased.

  According to the third aspect of the present invention, the cooling water temperature is not more than a predetermined temperature and the cooling water from the cylinder head cooling passage is directly flowed into the discharge chamber by the thermostatic temperature switching valve, and the cooling water temperature exceeds the predetermined value. The cylinder head cooling path switching function that allows the cooling water from the cylinder head cooling path to flow into the discharge chamber through the radiator, and the cooling water from the cylinder block cooling path to flow into the discharge chamber at all times, making the temperature sensitive The switching valve can be switched to function as a cylinder block thermostat.

  According to the fourth aspect of the present invention, since the flow path diameter of the cylinder block cooling water discharge path is smaller than the flow path diameter of the short circuit path, when the cooling water temperature is in an operating state exceeding a predetermined temperature, The cooling water flow rate can be sufficiently secured, and the cylinder head cooling efficiency can be sufficiently secured.

FIG. 1 shows an engine cooling apparatus as an embodiment of the present invention. This engine cooling device 1 is provided in a water-cooled engine 2 mounted on an automobile (not shown). In the engine 2, water jackets 5 and 6 are formed inside the cylinder block 3 and the cylinder head 4 that form the main part of the engine body 201.
The cylinder block 3 is formed with a first inflow port 7 at one end in the longitudinal direction and a first outflow port 8 at the other end, and a water jacket 5 communicating therewith causes a part of the discharge flow of the water pump 9 to flow. A block cooling path R1 is formed. The first inlet 7 communicates with the water pump 9 via the discharge path R2. Further, the cylinder block 3 is formed with an outflow path forming portion 10 protruding from an outer wall portion forming the first outlet 8. This outflow path forming portion 10 forms a cylinder block cooling water discharge path R01 that forms an extension of the cylinder block cooling path R1, and discharges the cooling water from the first outlet 8 through the extension pipe 11 to be described later. Lead to chamber 19.

  The cylinder head 4 has a second inlet 12 formed at one end in the longitudinal direction thereof and a second outlet 13 formed at the other end, and the water jacket 6 communicating with the cylinder head 4 flows the other part of the discharge flow of the water pump 9. A cylinder head cooling path R3 is formed. The second inlet 12 extends from the discharge path R4 and communicates its upstream end with the water pump 9 via the junction Ra of the discharge path R2. The water pump 9 receives the rotational force of the engine 2 through a belt-type rotation transmission system (not shown), sucks the cooling water from the suction port 901, and branches the cooling water from the discharge port 902 to the discharge paths R2 and R4 to be discharged. Is formed.

  Furthermore, a plurality of branch flow introduction holes 14 penetrating the cylinder block 3 and the cylinder head 4 are formed in the overlapping portion b. As shown in FIG. 3, a plurality of branch flow introducing holes 14 are formed in a concentrated manner on one end side (left side in FIG. 3) in the longitudinal direction of the overlapping portion b of the cylinder block 3 and the cylinder head 4. By introducing branch cooling water from the cylinder block 3 cooling path R1 into the cylinder head cooling path R3, it is easy to increase the pump flow rate at high rotation, and two are concentrated on the other end side (right side in FIG. 3). Thus, an increase in the flow rate of the cooling water circulating in the cylinder block 3 during high rotation and high load is dealt with.

As shown in FIG. 1, a casing 16 of a thermostat 15 is integrally attached to a side wall where the second outlet 13 of the cylinder head 4 is formed.
As shown in FIG. 2, the casing 16 includes a discharge chamber 19 that communicates with the cooling water suction passage R <b> 5 of the water pump 9 and accommodates the temperature-sensitive switching valve 18 at the center of the casing 16. Further, the thermostat 15 includes a first chamber 21 into which cooling water from the second outlet 13 flows with the discharge chamber 19 interposed therebetween, and a second chamber 24 into which cooling water from the heat radiation path R6 including the radiator 22 flows. . A first valve seat 26 is formed in the partition wall 25 between the first chamber 21 and the discharge chamber 19, and a second valve seat 28 is formed in the partition wall 27 between the second chamber 24 and the discharge chamber 19.

  The temperature-sensing switching valve 18 includes a core shaft 17 supported by a partition wall 27 integral with the casing 16 via a mounting bracket 29, a temperature-sensing portion (thermostat wax) 23 that is externally fitted so as to be movable relative thereto, and a temperature-sensing portion 23. The first and second valve bodies 33 and 34 supported by the outer shaft 31 that is integrally coupled, and the first spring that biases the first valve body 33 back to the reference position (the tip position of the outer shaft 31 indicated by the solid line). 35 and a second spring 36 that presses and urges the second valve body 34 and the outer shaft 31 toward the second valve seat 28.

  Here, the temperature changeover valve 18 is held at the cold position P0 at the normal temperature. Here, the second valve body 34 closes the second valve seat 28 by the second spring 36, the second chamber 24 and the discharge chamber 19 are closed, the first valve body 33 opens the first valve seat 26, and the first chamber A short circuit (bypass path) R7 between 21 and the discharge chamber 19 is communicated. On the other hand, when the temperature of the cooling water in the discharge chamber 19 exceeds a predetermined temperature (for example, 82 ° C.), the temperature sensing unit 23 and the outer shaft 31 side move relative to the core shaft 17, and the first valve seat 26 is moved to the first valve. The switching operation is performed so that the cooling water which is closed by the body 33 and is separated from the second valve seat 28 and is returned to the second chamber 24 from the heat radiation path R6 flows into the discharge chamber 19. In the operation range where the temperature of the cooling water exceeds a predetermined temperature (for example, 95 ° C.), the first valve body 33 is fully opened by the first valve body 33 and the second valve body 28 is fully opened by the second valve body 34.

Further, a discharge port 37 for discharging the cooling water reaching the discharge chamber 19 to the cooling water suction path R5 is formed at a portion of the casing 16 facing the discharge chamber 19. Further, an extension pipe 11 for connecting the cylinder block cooling water discharge path R01 to the discharge chamber 19 is connected to a position away from the discharge port 37.
For this reason, cooling water always flows into the discharge chamber 19 that houses the temperature-sensitive switching valve 18 from the cylinder block cooling path R1 through the cylinder block cooling water discharge path R01, bypasses the temperature sensing section 23, and is discharged. It is discharged from the outlet 37 to the cooling water suction path R5.

Here, at the portion of the casing 16 facing the first chamber 21, the cooling water that has reached the first chamber 21 is P1 at the position indicated by the two-dot chain line in FIG. A bypass port 38 that leads to a heat radiation path R6 including the radiator 22 is formed at a warm-up position). Here, the flow path diameter r1 of the bypass port 38 is sufficiently large, for example, set to φ28, so that even when the engine 2 is in a high rotation and high load operation, the cooling water corresponding to the pump discharge amount Qt has an excessive flow resistance. It can be circulated in a state where it does not occur. Note that the flow path diameter of the second valve seat 28 downstream of the heat dissipation path R6 is such that cooling water equivalent to the pump discharge amount Qt is circulated without causing excessive flow resistance even when the engine is operating at high speed and high load. In order to be able to do so, it is set to be equivalent to the bypass port 38, for example, φ28.
Further, the discharge port 37 of the casing 16 discharges the cooling water corresponding to the pump discharge amount Qt at the time of high rotation and high load in the entire operation range so that the cooling water can be led to the cooling water suction path R5 without causing excessive flow resistance. The channel cross-sectional area of the outlet 37 is sufficiently large, for example, set to φ30 or more.

  Here, in particular, the cylinder block cooling water discharge path R01 with respect to the flow path diameter r3 (for example, φ8) of the first valve seat 26, which is the flow path diameter of the short circuit path R7 between the first chamber 21 and the discharge chamber 19 of the thermostat 15. The channel diameter r4 (for example, φ6) is set to be small. That is, here, the flow rate of the cylinder block cooling water discharge passage R01 is set to be narrow. Accordingly, the flow rate qh of the cylinder head cooling path R3 is set to be sufficiently larger than the flow rate qb of the cylinder block cooling path R1, so that the cooling water flow rate of the cylinder head 4 does not occur in the entire operation region.

  Further, the flow path diameter r3 (for example, φ8) of the first valve seat 26 that regulates the cylinder head side flow rate and the flow path diameter r4 (for example, φ6) of the cylinder block cooling water discharge passage R01 that regulates the cylinder block side flow rate are set. The following points were taken into consideration.

Here, as shown in FIG. 5, the characteristics of the cylinder block flow rate qb and the cylinder head side flow rate qh (first valve seat) according to the change of the flow path diameter (cylinder block side flow path diameter) r4 of the cylinder block cooling water discharge path R01. The characteristics of 26 short-circuit paths R7 were measured.
As is clear from this, in the engine 1, when the flow path diameter r4 of the cylinder block cooling water discharge path R01 is sequentially increased and the engine speed Ne is sequentially changed to 1000, 2000, 3000, and 3500, the flow path diameter r4. There is no problem up to the vicinity of (for example, φ6), but when the flow path diameter r4 is larger than this, the flow rate qb on the cylinder block side is shifted to the rapidly increasing side, and the flow rate qh of the cylinder head cooling path R3 is shifted to the decreasing side. Turned out to be.

  As described above, when the flow path diameter r4 (for example, φ6) is exceeded in any rotation region, the flow rate qh of the cylinder head cooling path R3 shifts to the decreasing side, which tends to cause a decrease in cooling capacity due to a lack of cooling water in the cylinder head. It is considered. Accordingly, in the engine 1, in order to eliminate the decrease in the cooling capacity due to the lack of cooling water in the cylinder head, it is considered that the flow path diameter r4 of the cylinder block cooling water discharge path R01 is preferably set to φ6 or less. The flow path diameter r4 was set to φ6.

  As shown in FIG. 1, a branch outlet 40 is separately formed on the outer wall of the cylinder head 4 near the second outlet 13, and is connected to a heater circulation path 41 including a heater 39. . The downstream end of the heater circulation path 41 is connected so as to join the cooling water suction path R5. As a result, when an unillustrated on-off valve attached to the heater 39 is opened, the coolant can be circulated through the heater 39 at all times when the engine is driven to drive the heater. Here, the flow path diameter rh of the heater circulation path 41 is relatively large according to the heater capacity, and is set to φ16, for example.

The operation of the engine cooling device 1 will be described.
When the water pump 9 is driven during the cold start of the engine, the low-temperature cooling water branches into the first and second discharge paths R2 and R4 and then flows into the cylinder block cooling path R1 and the cylinder head cooling path R3. At this time, cooling water flows from the cylinder block cooling path R1 and the cylinder head cooling path R3 on the short circuit path R7 side into the discharge chamber 19, and the mixed cooling water flows around the temperature-sensitive switching valve 18. To the cooling water suction path R5.

  Therefore, while the temperature of the cooling water in the discharge chamber 19 is low, the temperature sensing switching valve 18 is held at the low temperature position P0 (solid line position), that is, the second valve body 34 closes the second valve seat 28 and the heat dissipation path. R6 is shut off, and the first valve element 33 opens the first valve seat 26 and communicates with the short circuit R7. In this warm-up operation region, the flow path diameter r4 of the cylinder block cooling water discharge path R01 is set smaller than the flow path diameter r3 of the first valve seat 26, so that the flow rate qh of the cylinder head cooling path R3 is the cylinder block cooling. The flow rate qb of the path R1 is maintained sufficiently higher, and without passing through the radiator 22, the cooling water can be circulated by short-circuiting the cooling water suction path R5 to warm up the engine.

  It is assumed that the engine speed Ne increases rapidly during this period. In this case, a part of the cooling water in the cylinder block cooling passage R1 passes through the plurality of branch flow introduction holes 14 due to the influence of the throttle action of the cylinder block cooling water discharge passage R01 having a relatively large passage resistance. It flows into the cylinder head cooling path R3 side having a relatively low resistance, and flows to the short circuit path R7 side. As described above, when the total pump flow rate is rapidly increased at the time of high pump rotation, an excessive increase in flow resistance can be eliminated by diverting the flow rate increment of the cooling water from the branch flow introduction hole 14 toward the cylinder head cooling path R3.

  Moreover, since a part of the branch flow introduction hole 14 is also formed on the other end side (right side in FIG. 3) of the cylinder block 3, the flow rate of the cooling water in the cylinder block 3 is suppressed by the throttle action of the cylinder block cooling water discharge passage R01. It is possible to increase the cooling efficiency of the cylinder block 3 in the high rotation / high load operation range, and to prevent excessive temperature rise.

  When the engine 2 is warmed up and the coolant temperature in the discharge chamber 19 rises above a predetermined temperature (for example, 82 ° C.), the amount by which the temperature sensing unit 23 and the outer shaft 31 move relative to the core shaft 17 increases. For this reason, the degree to which the first valve seat 26 is closed by the first valve body 33 and the degree to which the second valve body 34 is separated from the second valve seat 28 are further increased, and eventually returned from the heat radiation path R6 to the second chamber 24. The cooling water is surely flowed into the discharge chamber 19. As described above, the switching when the warm-up is completed starts when the mixed cooling water exceeds a predetermined temperature (for example, 82 ° C.), and then reaches, for example, about 95 ° C., the temperature-sensitive switching valve 18 is moved to the fully open position P1. The flow resistance of the cooling water from the heat radiation path R6 and the cylinder block cooling water discharge path R01 in the thermostat 15 can be reduced most.

  As described above, when the cooling water temperature is equal to or lower than a predetermined temperature (for example, 82 ° C.), the temperature sensing switching valve 18 of the thermostat 15 passes the cooling water from the cylinder head cooling path R3 from the second outlet 13 through the short circuit R7. When the coolant temperature is guided to the discharge chamber 19 and exceeds the predetermined temperature, the switching operation is performed so that the coolant from the cylinder head cooling path R3 is guided to the discharge chamber 19 via the radiator 22.

  When the temperature sensitive switching valve 18 is switched, the cooling water from the heat radiation path R6 flows into the discharge chamber 19 instead of the cooling water from the short circuit path R7. There is almost no change in the amount of inflow, that is, the amount of cooling water passing through the cylinder head 4 is not greatly reduced and can be switched at the completion of stable warm-up, and in particular, a sudden decrease in the cooling water in the cylinder head 4 is prevented. It is possible to reliably avoid a decrease in the cooling performance of the cylinder head 4 due to a lack of cooling water.

  Further, in the engine cooling device 1 of FIG. 1, the cooling water from the first outlet 8 is returned from the cylinder block cooling water discharge path R01 to the cooling water suction path R5 through the discharge chamber 19. For this reason, the cooling water from the cylinder block 3 always passes around the temperature-sensitive switching valve 18, and the change in the temperature of the cooling water in the cylinder block 3 is reflected in the switching of the thermostat 15 to the circulation cooling water R6. The amount of heat dissipation can be adjusted by adjusting the amount of detour. For this reason, it is not necessary to provide a separate thermostat in the cylinder block cooling water discharge path R01, and the thermostat 15 of the cylinder head cooling path R3 can also be used, which facilitates cost reduction.

  Next, an engine cooling device 1a as a second embodiment of the present invention will be described with reference to FIGS. The engine cooling device 1a is different from the engine cooling device 1 of FIG. 1 in the configuration of the cylinder block cooling water discharge path R01a and the discharge port 37a of the thermostat 15a, and the other configurations are the same. Then, the description of the overlapping component is omitted.

As shown in FIG. 6, the cylinder block 3 to which the engine cooling device 1 a is applied has an outflow passage forming portion 10 a that protrudes from the outer wall portion that forms the first outlet 8, and this is an extension of the cylinder block cooling passage R <b> 1. A cylinder block cooling water discharge path R01a forming a part is formed. Here, one end of the extension pipe 11a is connected to the outflow path forming portion 10a, and the other end is connected to the inflow chamber 21 of the thermostat 15a.
The thermostat 15a has substantially the same configuration as the above-described thermostat 15, except that the other end of the extension pipe 11a communicates with the inflow chamber 21 instead of the discharge chamber 19.

  In this case, when the short circuit R7, which is a bypass path, is opened, the cooling water from the first outlet 8 of the cylinder block 3 and the second outlet 13 of the cylinder head 4 in the inflow chamber 21 before reaching the short circuit R7. The cooling water from will be mixed. The cooling water mixed here becomes a flow from only one direction, reaches the temperature sensing part 23 of the thermostat 15, and senses the temperature of the part. Accordingly, since the temperature sensing unit 23 senses the temperature of the mixed water of the cooling water from the first outlet 8 and the cooling water from the second outlet 13, even if the water temperature from the second outlet 13 is constant, the first If the water temperature from the outlet 8 changes, the temperature of the mixed water changes, and the thermostat valve opening amount can change.

  When the thermostat 15 as shown in FIG. 2 is used, an additional member such as a water introduction guide plate (not shown) that guides cooling water to the temperature-sensitive portion 23 of the thermostat is required in order to improve the temperature sensitivity of the temperature-sensitive portion 23 of the thermostat. There is a case. When such a thermostat 15 is used, the shape in the thermostat case 16 may be complicated. However, like the thermostat 15 a shown in FIG. 7, the cooling water from the first outlet 8 in the inflow chamber 21 in advance is used. If the cooling water from the second outlet 13 is mixed, the mixed water can be easily guided to the temperature sensing part 23 without the need for additional members as described above, and there is no special device. Good and simple shape.

Except for the above points, the engine cooling device 1a shown in FIG. 6 can exhibit the same functions as the engine cooling device 1 of FIG. 1 and can obtain the same functions and effects.
In the above description, the flow path diameter r4 (for example, φ6) of the cylinder block cooling water discharge path R01 is smaller than the flow path diameter r3 (for example, φ8) of the first valve seat 26 that is the flow path diameter of the short circuit R7 of the thermostat 15. It set so that it might become small. As a result, the flow rate of the cylinder block cooling water discharge passage R01 is set to be narrow, so that the cooling water flow rate shortage of the cylinder head cooling passage R3 does not occur. The value is not limited to the above-mentioned value, and is increased or decreased in accordance with the setting of the flow rate ratio between the cylinder block cooling path R1 and the cylinder head cooling path R3. The flow path diameter r4 is set so as to be small, and an insufficient coolant flow rate in the cylinder head cooling path R3 is prevented.

  Although the above-described thermostats 15 and 15a have been described as being switched by the temperature-sensitive switching valve 18, in some cases, instead of the temperature-sensitive switching valve 18, the electromagnetic switching valve 18a shown in FIG. The first and second valve bodies 33 and 34 may be switched and driven).

  The electromagnetic switching valve 18 a is equipped with a driving solenoid 42 on the outer wall side of the casing 16, and supports the movable shaft 31 a slidably on the inner wall side of the casing 16 via a support frame 44. One end of the movable shaft 31a is connected to be driven by a solenoid 42, and the first and second valve bodies 33 and 34 are supported on the other end and the intermediate side. The solenoid 42 is connected to the controller 43 via a drive circuit (not shown). The controller 43 takes in each cooling water temperature of the cooling passages R1 and R3 by a temperature sensor (not shown), and the first and second valve bodies 33 and the first and second valve seats 26 and 28 according to the temperature information. 34 may be configured to be switched and controlled. In the case of the thermostat 15a provided with the electromagnetic switching valve 18a, as in the case of the thermostat 15a in FIG. 1, there is almost no change in the flow rate of the cooling water on the cylinder head 4 side when switching to the warm-up completion, and the cylinder block 3 and the cylinder head The temperature-sensitive switching valve 18 can stably detect the influence of the temperature of both cooling waters No. 4 and can perform switching at the time of stable warm-up completion, can eliminate the thermostat from the cylinder block side, and can easily reduce the cost.

  In the above description, the overlapping portion b between the cylinder block 3 and the cylinder head 4 has a plurality of branch flow introduction holes 14 at one end side and the other end side in the longitudinal direction of the overlapping portion b between the cylinder block 3 and the cylinder head 4. However, the present invention is not limited to this, and an appropriate amount of the branch flow introduction hole is set so as to meet temperature setting conditions such as maintaining the cylinder block 3 side at a higher temperature than the cylinder head 4. 14 may be arranged in a distributed manner, and in this case as well, substantially the same effect as the engine cooling device 1 of FIG. 1 can be obtained.

  In the above description, the engine cooling device is used in a vehicle engine, but can be widely applied to a water-cooled engine used as a drive source of various industrial equipment.

It is the whole engine cooling device schematic diagram as one embodiment of the present invention. It is an expanded sectional view of the thermostat used with the engine cooling device of FIG. It is a partial expanded sectional view of the modification of the thermostat used with the engine cooling device of FIG. FIG. 2 is an enlarged plan view of an upper wall surface of a cylinder block of an engine equipped with the engine cooling device of FIG. 1. FIG. 2 is a diagram showing a relative characteristic between a flow rate of a cylinder block cooling path and a flow rate of a cylinder head cooling path of an engine equipped with the engine cooling device of FIG. 1 with an engine speed as a parameter. It is a whole schematic block diagram of the engine cooling device as other embodiment of this invention. It is an expanded sectional view of the thermostat used with the engine cooling device of FIG. FIG. 2 is an engine rotation speed-discharge amount characteristic diagram of cooling water at each outlet of a cylinder block and a cylinder head of the engine cooling device of FIG. 1. It is a whole schematic block diagram of the conventional engine cooling device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine cooling device 3 Cylinder block 4 Cylinder head 8 1st outflow port 9 Water pump 13 2nd outflow port 14 Branch flow introduction hole 15 Thermostat 18 Temperature-sensitive switching valve 19 Discharge chamber 21 1st chamber 22 Radiator 24 2nd chamber b Polymerization Part R01 Cylinder block cooling water discharge path R1 Cylinder block cooling path R3 Cylinder head cooling path R5 Cooling water suction path R6 Heat radiation path R7 Short circuit path

Claims (4)

A cylinder block cooling passage for introducing a part of the discharge flow of the water pump into the cylinder block and leading it to the first outlet;
A cylinder head cooling passage for introducing another part of the discharge flow into the cylinder head and leading it to the second outlet;
A discharge chamber that communicates with the cooling water suction passage of the water pump and accommodates a temperature-sensitive switching valve is provided. When the cooling water temperature is equal to or lower than a predetermined temperature, the cooling water from the second outlet is guided to the discharge chamber, A thermostat that switches and operates so as to guide the cooling water from the second outlet through the radiator to the discharge chamber when the water temperature exceeds a predetermined temperature;
A cylinder block cooling water discharge passage for guiding cooling water from the first outlet to the discharge chamber;
An engine cooling device comprising: The engine cooling device according to claim 1.
An engine cooling apparatus, wherein a branch flow introduction hole for introducing branch cooling water from the cylinder block cooling path into the cylinder head cooling path is formed in a superposed portion of the cylinder block and the cylinder head. The engine cooling device according to claim 1 or 2,
The thermostat includes a first chamber into which cooling water from the second outlet flows and a second chamber into which cooling water from a heat radiation path including the radiator flows, with a cooling water temperature being predetermined. The temperature-sensitive switching valve is switched so that the cooling water in the first chamber flows into the discharge chamber when the temperature is lower than the temperature, and the cooling water in the second chamber flows into the discharge chamber when the cooling water temperature is equal to or higher than a predetermined temperature. Engine cooling device. The engine cooling device according to claim 1, 2, or 3,
An engine cooling apparatus characterized in that the flow path diameter of the cylinder block cooling water discharge path is set smaller than the flow path diameter of the short circuit path between the first chamber and the discharge chamber .

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