JP5720386B2 - Engine cooling system - Google Patents

Description

  The present invention supplies an engine coolant circulation path for taking out and returning the coolant of an engine with a supercharger to the outside, and a water-cooled intercooler for cooling the compressed intake air from the turbocharger compressor. The present invention relates to an engine cooling device capable of circulating a coolant independently of an intercooler coolant circulation path through which the coolant is circulated.

  For example, in Patent Document 1, an engine cooling water circulation path is connected to a water jacket of an engine with a supercharger, and an aftercooler cooling water circulation path for cooling compressed intake air from the turbocharger compressor is connected to the engine cooling water circulation path. However, a configuration is described in which the coolant can be circulated independently in both the circulation paths.

  The engine coolant circulation path is provided with a radiator, a bypass passage for bypassing the radiator, and a water pump for flowing the coolant.

  The aftercooler cooling water circulation path includes an aftercooler for cooling the compressed intake air from the turbocharger compressor, a cooler cooling radiator for cooling the aftercooler, and a bypass for bypassing the cooler cooling radiator. A passage and a water pump for flowing the cooling water are installed.

  A thermostat is installed in each of the cooling water forward path and the cooling water return path for communicating the engine cooling water circulation path and the aftercooler cooling water circulation path.

  In Patent Document 1, the engine cooling water is circulated to the aftercooler without being circulated to the cooler cooling radiator during the engine warm-up operation, and the intake air is actively heated, and the engine cooling water circulation is performed during the normal operation after the warm-up is completed. The intake air is cooled by allowing the cooler cooling water in the aftercooler cooling water circulation path, which is disconnected from the passage, to flow through the aftercooler via the cooler cooling radiator.

Japanese Utility Model Publication No. 57-81437

  In Patent Document 1, two thermostats open and close based on the coolant temperature in the engine coolant circulation path. For example, in order to prevent freezing of the aftercooler when the outside air is at a very low temperature, the aftercooler cooling is performed. There is no description of opening and closing the two thermostats triggered by the cooling water temperature in the water circulation path.

  As a reference example, for example, in paragraph 0022 of JP 2010-43555 A, a throttle body is circulated by always circulating a part of cooling water discharged from the cylinder head outlet side passage through the throttle passage. It is described to prevent freezing. Since the engine of this patent document is not equipped with a supercharger or an intercooler, the premise configuration is different from that of the present invention. Of course, this patent document also contains no description related to the prevention of freezing of the intercooler. Absent.

  In view of such circumstances, the present invention provides an engine coolant circulation path for taking out the coolant of an engine with a supercharger to the outside and returning it, and water cooling for cooling the compressed intake air from the supercharger compressor. In the engine cooling device that enables the coolant to circulate independently through the intercooler coolant circulation path through which the coolant supplied to the intercooler of the type is circulated, the intercooler is frozen when the outside air is at a very low temperature. It aims to make it possible to prevent.

  The present invention supplies an engine coolant circulation path for taking out and returning the coolant of an engine with a supercharger to the outside, and a water-cooled intercooler for cooling the compressed intake air from the turbocharger compressor. An engine cooling device capable of circulating a coolant independently of an intercooler coolant circulation path through which the coolant is circulated, wherein the coolant is supplied from the engine coolant circulation path to the intercooler coolant circulation path. An introduction path for allowing the coolant to be introduced, a return path for allowing the coolant to recirculate from the intercooler coolant circulation path to the engine coolant circulation path, and a coolant flow rate in the introduction path are changed. And a control unit that opens the valve body when the coolant temperature in the intercooler coolant circulation path is equal to or lower than a predetermined threshold value.

  Generally, when the engine is cold started, the temperature of the coolant in the engine coolant circulation path rises relatively early due to the heat of the combustion chamber of the engine, and when the engine warm-up is completed, the coolant temperature in the engine coolant circulation path Is kept at the warm-up completion temperature.

  By the way, the cooling liquid in the intercooler coolant circulation path needs to be at a relatively low temperature because of the relationship aimed at cooling the compressed intake air from the supercharger compressor with a water-cooled intercooler. However, for example, if the engine coolant circulation path and the intercooler coolant circulation path are not connected in a situation where the outside air is at a very low temperature, the temperature of the coolant in the intercooler coolant circulation path does not increase. There is a concern that moisture contained in the compressed intake air adheres to the outer surface of the water and freezes.

  Therefore, in the present invention, the engine coolant circulation path and the intercooler coolant circulation path are made to communicate with each other by opening the valve body when the coolant temperature of the intercooler coolant circulation path is equal to or lower than the threshold value. Therefore, the relatively high temperature coolant in the engine coolant circulation path is introduced into the intercooler coolant circulation path via the introduction path, and the coolant in the intercooler coolant circulation path is warmed. . Therefore, the freezing of the intercooler is avoided even when the outside air is at a very low temperature, so that the phenomenon that the intercooler excessively cools the compressed intake air from the supercharger compressor can be avoided. .

  Preferably, the control unit may close the valve body when a coolant temperature in the intercooler coolant circulation path exceeds the predetermined threshold.

  If the coolant in the engine coolant circulation path reaches the warm-up completion temperature while the valve body is open, the coolant temperature in the intercooler coolant circulation path also becomes the coolant in the engine coolant circulation path. Since it becomes almost the same as the temperature, the intercooler heats the compressed intake air from the supercharger compressor, and there is a concern that the compressed intake air becomes higher than the target intake air temperature.

  On the other hand, in the configuration of the present invention, the valve body is closed when the temperature of the coolant in the intercooler coolant circulation path is raised to exceed the threshold value. As a result, the relatively high temperature coolant in the engine coolant circulation path is not introduced into the intercooler coolant circulation path, so that the coolant in both circulation paths circulate independently. Therefore, it is possible to prevent the coolant in the intercooler coolant circulation path from rising more than necessary, so the intercooler can cool the compressed intake air from the turbocharger compressor. (Cooling action) can be ensured.

  Preferably, the threshold value is higher than the coolant temperature of the intercooler coolant circulation path when moisture contained in the compressed intake air from the supercharger compressor adheres to the outer surface of the intercooler and freezes. The lower limit value is a cooling target temperature that can be cooled by the intercooler to the cooling target temperature of the compressed intake air from the turbocharger compressor, and the upper limit value is set in the range from the lower limit value to the upper limit value. Is set.

  In this configuration, it is possible to prevent the intercooler from freezing when the temperature of the coolant in the intercooler coolant circulation path is lower than the threshold, and the temperature of the coolant in the intercooler coolant circulation path is When higher than the threshold, the intercooler can cool the compressed intake air by the supercharger compressor. In this way, it is possible to achieve both prevention of freezing of the intercooler and securing of cooling performance.

  Preferably, the intercooler coolant circulation path is installed in the throttle valve so that heat can be exchanged with the throttle valve attached to the engine by the coolant of the intercooler coolant circulation path. Can be configured.

  Here, a throttle valve is installed in the intercooler coolant circulation path. In this configuration, as described above, the temperature of the coolant in the intercooler coolant circulation path is raised relatively early in the engine coolant circulation path by opening the valve body as a trigger when the temperature is below the threshold value. When the coolant to be heated is introduced from the introduction path into the intercooler coolant circulation path, the coolant in the intercooler coolant circulation path, the intercooler, and the throttle even when the outside air is at a very low temperature It is possible to warm the valve. Therefore, the intercooler can appropriately heat the compressed intake air from the supercharger compressor, and the movement of the throttle valve is improved.

  Then, the temperature of the coolant in the intercooler coolant circulation path exceeds the threshold because the coolant in the intercooler coolant circulation path is heated by a relatively high temperature coolant in the engine coolant circulation path. Since the valve body is sometimes closed, the coolant in the intercooler coolant circulation path is maintained in a predetermined temperature range without increasing the temperature more than necessary. As a result, the intercooler is prevented from unnecessarily heating the compressed intake air from the supercharger compressor, and the original function (cooling action) of cooling the intercooler to the target temperature is exhibited. At the same time, the throttle valve is prevented from being heated unnecessarily, and the throttle valve is reliably cooled.

  Preferably, a radiator for exchanging heat between the coolant in the intercooler coolant circulation path and the outside air is installed in the intercooler coolant circulation path.

  In this configuration, when the coolant in the intercooler coolant circulation path recovers the heat of the intercooler or the throttle valve, the heat of the coolant is released to the atmosphere by the radiator. However, if the engine coolant circulation path and the intercooler coolant circulation path are not communicated when the outside air is at a very low temperature, the coolant in the intercooler coolant circulation path is cooled by the radiator. The temperature is lowered to a temperature corresponding to the outside air.

  In such a case, since the coolant temperature in the intercooler coolant circulation path becomes equal to or lower than the threshold value, the valve body is opened accordingly, and the coolant coolant in the engine coolant circulation path is relatively hot. Is introduced into the intercooler coolant circulation path. As a result, when the outside air is at a very low temperature, the intercooler and the throttle valve are warmed, so that the intercooler can be prevented from freezing and the throttle valve can be moved easily.

  Preferably, a water pump is provided in each of the engine coolant circulation path and the intercooler coolant circulation path, and the water pump in the intercooler coolant circulation path is electrically operated.

  In this configuration, it is possible to arbitrarily set the circulation rate of the coolant in the intercooler coolant circulation path by controlling the capacity of the electric water pump.

  Preferably, the valve body is an electromagnetic valve, and the control unit is configured to input an output signal from a temperature sensor that detects a coolant temperature of the intercooler coolant circulation path. The ECU can recognize the coolant temperature and control the opening / closing operation of the solenoid valve by comparing the recognition result with the threshold value.

  Preferably, the control unit senses a coolant temperature of the intercooler coolant circulation path, and is a thermoactuator that opens the valve body when the sensing result is equal to or less than the threshold, and the thermoactuator and the valve The body constitutes a thermostat.

  The thermostat means a temperature sensing type automatic operation valve in the automobile related industry. When such a thermostat is used, a temperature sensor and a control system are not necessary, and it is possible to suppress an unnecessary increase in equipment cost.

  Preferably, the engine coolant circulation path includes an internal passage of the engine, a circulation passage connected to a coolant discharge port and a coolant introduction port of the internal passage, and a water pump provided on the way, and the circulation passage. A radiator passage connected in parallel to the upstream side of the radiator and a radiator installed in the middle thereof, and disposed on the downstream side of the radiator in the radiator passage and closed when the coolant is below the warm-up completion temperature And a thermostat that is fully opened when the temperature is equal to or higher than the warm-up completion temperature.

  The present invention supplies an engine coolant circulation path for taking out and returning the coolant of an engine with a supercharger to the outside, and a water-cooled intercooler for cooling the compressed intake air from the turbocharger compressor. In the engine cooling device that enables the coolant to circulate independently in each of the intercooler coolant circulation paths through which the coolant is circulated, the intercooler can be prevented from freezing when the outside air is at a very low temperature. Become.

It is a figure showing the schematic structure of one embodiment of the engine cooling device concerning the present invention. It is a figure which shows schematic structure of other embodiment of the engine cooling device which concerns on this invention, and has replaced the solenoid valve of FIG. 1 with the thermostat. It is a figure which shows schematic structure of further another embodiment of the engine cooling device which concerns on this invention, is replacing the electromagnetic valve of FIG. 1 with the thermostat, and has installed the check valve in the return path.

  BEST MODE FOR CARRYING OUT THE INVENTION Best modes for carrying out the present invention will be described in detail below with reference to the accompanying drawings.

  FIG. 1 shows an embodiment of the present invention. The engine of this embodiment is a supercharged engine. The engine is provided with an engine coolant circulation path 20 for taking out the coolant and returning it to the outside. The engine coolant circulation path 20 includes an internal passage of the engine and an external passage of the engine.

  The internal passage of the engine includes a water jacket 13 provided in the cylinder block of the engine and a water jacket 14 provided in the cylinder head of the engine. The external passage of the engine includes a heater passage 21, a radiator passage 22, and an auxiliary machinery passage 23.

  The heater passage 21 circulates the coolant discharged from at least one of the block-side water jacket 13 and the head-side water jacket 14 to at least one of the block-side water jacket 13 and the head-side water jacket 14. It is.

  The heater passage 21 is provided with a water pump 4 and a heater core 5. The water pump 4 is provided in the heater passage 21 at a position near the coolant introduction portion of the block-side water jacket 13. The heater core 5 is a heat exchanger for heating the vehicle interior, and is provided in the heater passage 21 at a position near the coolant discharge portion of the head side water jacket 14.

  Although not shown, the water pump 4 is a mechanical type driven by a crankshaft of the engine. Although not shown in detail, the mechanical water pump 4 has the same configuration as a known configuration in which a belt is wound around a water pump pulley and a crankshaft pulley, and the water pump pulley is equipped with an electromagnetic clutch or the like. ing. The water pump 4 is operated or stopped by connecting and disconnecting the electromagnetic clutch with the ECU 100.

  Further, an electromagnetic valve 24 is provided on the upstream side of the coolant introduction portion of the block-side water jacket 13 in the heater passage 21. The opening / closing operation of the electromagnetic valve 24 is controlled by an electronic control unit (hereinafter referred to as ECU) described below.

  The radiator passage 22 is connected in parallel to the upstream side of the heater passage 21, and the radiator 6 is provided in the middle of the radiator passage 22.

  The radiator 6 is a heat exchanger that exchanges heat between the coolant and the atmosphere. In the radiator passage 22, the downstream side in the coolant flow direction from the radiator 6 is connected between the water pump 4 and the heater core 5 through the thermostat 7 in the heater passage 21.

  Although the thermostat 7 has a known configuration and is not shown in detail, when the coolant temperature at the installation location of the thermostat 7 becomes lower than the warm-up completion temperature (for example, about 88 ° C.) Th, the thermowax is solidified and contracted. Since the wax pressure is lowered, the valve body is automatically closed to reduce the flow of the coolant from the radiator passage 22 to the water pump 4, but the temperature of the coolant at the place where the thermostat 7 is installed has been warmed up. When the temperature becomes equal to or higher than the temperature Th, the thermowax is melted and expanded to increase the wax pressure, so that the valve body is automatically fully opened to allow the coolant to flow from the radiator passage 22 to the water pump 4.

  Specifically, the thermostat 7 is fully closed when the temperature is lower than a predetermined temperature (for example, 82 ° C.) lower than the warm-up completion temperature Th, starts opening from the predetermined temperature, and is fully opened when the warm-up completion temperature Th is reached. Become.

  The auxiliary machine passage 23 is provided between the coolant discharge portion of the head side water jacket 14 and the heater core 5 and between the heater core 5 and the downstream connection portion of the radiator passage 22 with respect to the heater passage 21. The auxiliary machine passage 23 is provided with an EGR cooler 8 and an EGR valve 9.

  The EGR cooler 8 and the EGR valve 9 are provided in an EGR system for suppressing the generation of NOx by returning a part of the exhaust discharged from the engine to the intake system (not shown) of the engine. The EGR cooler 8 is a heat exchanger for absorbing the heat of the exhaust gas that is returned to the intake system and cooling the exhaust gas. The EGR cooler 8 can exchange heat with the coolant flowing through the auxiliary passage 23. Installed as possible. The EGR valve 9 adjusts the amount of EGR that returns to the intake passage of the engine.

  Furthermore, although not shown in detail in the engine of this embodiment, a supercharger is attached. This turbocharger is, for example, a known turbocharger, and includes a turbine provided in an exhaust passage of the engine, a compressor provided in an intake passage of the engine, and a rotary shaft to which the turbine and the compressor are fixed at both ends. .

  As the operation of the turbocharger, the turbine is rotated by the exhaust gas flowing from the inlet of the turbine housing (see reference numeral 36 in FIG. 1) in the exhaust passage. When the turbine is rotated, the rotary shaft and the compressor are integrally rotated. As the compressor rotates, the intake air drawn into the compressor housing in the intake passage is compressed (supercharged). The compressed intake air increases in density and temperature.

  In order to cool the intake air (compressed intake air supplied to the engine) compressed by such a supercharger compressor, a water-cooled intercooler 31 is provided.

  The water-cooled intercooler 31 includes a heat exchanger for exchanging heat between the compressed intake air from the supercharger compressor and the coolant. The coolant supplied to the intercooler 31 is circulated in the intercooler coolant circulation path 30.

  The intercooler coolant circulation path 30 is a closed loop and is provided in the vicinity of the engine coolant circulation path 20. An intercooler 31, a radiator 32, a throttle valve 33, and an electric water pump 34 are installed in the intercooler coolant circulation path 30.

  The coolant that fills the intercooler coolant circulation path 30 is the same as the coolant in the engine coolant circulation path 20. The coolant is, for example, an aqueous solution of ethylene glycol.

  The radiator 32 is a heat exchanger for exchanging heat between the coolant in the intercooler coolant circulation path 30 and the outside air. The throttle valve 33 adjusts the intake air amount of the engine as is well known, and a part of the intercooler coolant circulation path 30 is inserted into a predetermined portion of the throttle valve 33 so that heat can be exchanged. . The electric water pump 34 causes the coolant to flow in the intercooler coolant circulation path 30, and its operation is controlled by the ECU 100.

  In operation, the coolant is circulated in the closed loop intercooler coolant circulation path 30 by the electric water pump 34, and the heat accumulated in the intercooler 31 and the throttle valve 33 is recovered by the circulating coolant. The heat of the coolant is released to the atmosphere by the radiator 32.

  The intercooler coolant circulation path 30 is inserted into the turbine housing 36 so that heat can be exchanged between the coolant and the turbine housing 36 of the supercharger. Thereby, the turbine housing 36 can be cooled with the coolant of the intercooler coolant circulation path 30.

  An introduction path 41 and a reflux path 42 are connected to the engine coolant circulation path 20 and the intercooler coolant circulation path 30. The introduction path 41 is a communication path for enabling the introduction of the coolant from the engine coolant circulation path 20 to the intercooler coolant circulation path 30, and the reflux path 42 is the engine coolant circulation from the intercooler coolant circulation path 30. This is a communication path for allowing the coolant to return to the path 20.

  An electromagnetic valve 43 is installed in the introduction path 41. The electromagnetic valve 43 changes the coolant flow rate of the introduction passage 41, and its opening / closing operation is controlled by the ECU 100.

  The ECU 100 is an engine control computer for controlling various operations of the engine, for example. In this embodiment, the existing ECU 100 is equipped with a function for controlling the electromagnetic valves 24 and 43 and the electric water pump 34.

  Although not shown in detail, the ECU 100 has a known configuration including a CPU (central processing unit), a ROM (program memory), a RAM (data memory), a backup RAM (nonvolatile memory), and the like.

  The ROM stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU executes arithmetic processing based on various control programs and maps stored in the ROM. The RAM is a memory that temporarily stores calculation results in the CPU, data input from each sensor, and the backup RAM is a non-volatile memory that stores data to be saved when the engine is stopped. It is.

  In this embodiment, a temperature sensor 35 for detecting the temperature of the coolant is provided upstream of the radiator 32 in the intercooler coolant circulation path 30 in the coolant circulation direction. In the intercooler coolant circulation path 30, the coolant on the upstream side in the coolant circulation direction with respect to the radiator 32 has a higher temperature than the coolant on the downstream side in the coolant circulation direction with respect to the radiator 32. Needless to say, when the coolant passes through the radiator 32, the heat of the coolant is released to the atmosphere, so that the temperature of the coolant is lowered downstream of the radiator 32. 31 and the turbocharger turbine housing 36 recover their heat so that the temperature of the coolant reaching the upstream side of the radiator 32 increases.

  The temperature sensor 35 outputs a signal corresponding to the temperature of the coolant and inputs it to the ECU 100. The ECU 100 recognizes the coolant temperature Tc based on the input of the output signal of the temperature sensor 35, and controls whether the solenoid valve 43 is opened or closed by determining whether or not the recognition result Tc is equal to or less than a predetermined threshold Tx. . The electromagnetic valve 43 is opened when the recognition result Tc is less than or equal to the threshold value Tx, and the electromagnetic valve 43 is closed when the recognition result Tc exceeds the threshold value Tx.

  The threshold value Tx is set within an appropriate temperature range. About the lower limit of this temperature range, it is higher than the coolant temperature of the intercooler coolant circulation path 30 when water contained in the compressed intake air from the supercharger compressor adheres to the outer surface of the intercooler 31 and freezes. The temperature can be set (eg, about 5 ° C.). The upper limit of the temperature range is equal to or lower than the coolant temperature (for example, about 49 ° C.) that can be cooled by the intercooler 31 to the target cooling temperature (for example, about 50 ° C.) of the compressed intake air from the supercharger compressor. Temperature can be set.

  Thus, if the threshold value Tx is appropriately set within the temperature range, it is possible to prevent the intercooler 31 and the throttle valve 33 from freezing, and the intercooler 31 allows compressed intake air from the supercharger compressor to be discharged. It is possible to appropriately exhibit the temperature control performance for adjusting to the target temperature.

  Next, engine temperature adjustment control by the ECU 100 will be described.

  When the engine is started, the ECU 100 first recognizes the temperature of the coolant discharged from the head-side water jacket 14 based on the input of the output signal from the temperature sensor 25, and this recognition result is less than the warm-up completion temperature Th. It is determined whether or not.

  Here, since the thermostat 7 is closed when the temperature of the coolant is lower than the warm-up completion temperature Th, that is, when the engine is cold started, the mechanical water pump 4 that is actuated as the engine starts is used to close the engine. The coolant discharged from the internal passages (13, 14) is returned to the internal passages (13, 14) of the engine through the heater passage 21. As a result, the temperature of the engine is raised by the heat of the combustion chamber of the engine, and the temperature of the coolant is raised relatively early.

  On the other hand, when the temperature of the coolant is equal to or higher than the warm-up completion temperature Th, that is, when the engine is in normal operation, the thermostat 7 is open, and therefore, the coolant is discharged from the internal passages (13, 14) of the engine. The coolant is returned to the internal passages (13, 14) of the engine through the heater passage 21 and the radiator passage 22 in the engine coolant circulation passage 20. In this case, the coolant passing through the internal passages (13, 14) of the engine recovers the heat of the cylinder head and the cylinder block, and the heat of the coolant is dissipated to the atmosphere by the radiator 6. Therefore, the temperature of the coolant circulating in the engine coolant circulation path 20 is maintained at the warm-up completion temperature Th.

  By the way, the ECU 100 circulates the coolant in the intercooler coolant circulation path 30 by operating the electric water pump 34 during the warm-up operation described above, and based on the input of the output signal from the temperature sensor 35. In the intercooler coolant circulation path 30, the coolant temperature Tc on the upstream side in the coolant circulation direction of the radiator 32 is recognized, and it is determined whether or not the recognition result Tc is equal to or less than the threshold value Tx.

  Here, when the recognition result Tc is equal to or less than the threshold value Tx, the ECU 100 opens the electromagnetic valve 43 so that a relatively high temperature coolant circulating in the engine coolant circulation path 20 is supplied from the introduction path 41 to the intercooler coolant. It is made to introduce into the circulation path 30.

  As a result, the coolant in the intercooler coolant circulation path 30, the intercooler 31, and the throttle valve 33 are gradually warmed, so that the intercooler 31 and the throttle valve 33 can be frozen even when the outside air is at a very low temperature. You will not have to. Therefore, even if the outside air is at a very low temperature, the intercooler 31 does not excessively cool the compressed intake air by the supercharger compressor, and the intercooler 31 can appropriately heat the compressed intake air. The movement of the throttle valve 33 is improved.

  When the recognition result Tc exceeds a predetermined threshold value Tx by gradually increasing the temperature of the coolant in the intercooler coolant circulation path 30 in this way, the ECU 100 closes the electromagnetic valve 43 to The coolant is circulated independently in the intercooler coolant circulation path 30 so that the relatively high temperature coolant circulating in the coolant circulation path 20 is not introduced into the intercooler coolant circulation path 30.

  Thereby, the coolant that passes through the intercooler 31 recovers the heat of the compressed intake air from the turbocharger compressor, and the coolant that passes through the throttle valve 33 recovers the heat of the throttle valve 33 with the coolant, When the coolant passes through the radiator 32, the recovered heat is released to the atmosphere by the radiator 32.

  In this way, the coolant circulating in the intercooler coolant circulation path 30 is maintained in a predetermined temperature range without increasing the temperature more than necessary. Therefore, the intercooler 31 is prevented from unnecessarily heating the compressed intake air from the supercharger compressor, so that the intercooler's original function (cooling action) of cooling to the target temperature is exhibited. At the same time, the throttle valve 33 is prevented from being heated unnecessarily, and the throttle valve 33 is reliably cooled.

  In the engine cooling apparatus configured as described above, when the engine is cold started, the outside air is at a very low temperature and the engine coolant circulation path 20 and the intercooler coolant circulation path 30 are not in communication. Then, the coolant in the intercooler coolant circulation path 30 is lowered by the radiator 32 to a temperature close to extremely low temperature outside air, so that the intercooler 31 and the throttle valve 33 are easily frozen, and the intercooler 31 excessively cools the compressed intake air from the supercharger compressor, and the trouble that the throttle valve 33 becomes difficult to move easily occurs.

  In consideration of such points, in the embodiment to which the present invention is applied, in the above situation, the engine cooling is performed such that the electromagnetic valve 43 is opened and the temperature is raised relatively quickly as the engine is cold started as described above. Since the coolant in the liquid circulation path 20 is introduced into the intercooler coolant circulation path 30, the above problem can be solved. In other words, even when the engine is cold started when the outside air is at a very low temperature, the intercooler 31 can avoid excessive cooling of the compressed air, and the throttle valve 33 can be moved easily. become.

  Then, if the temperature of the coolant in the intercooler coolant circulation path 30 is raised until the temperature exceeds the threshold value Tx by dealing with the above, the engine coolant circulation path 20 and the intercooler coolant circulation path 30 are not connected. The cooling of the intercooler coolant circulation path 30 is performed by the radiator 32 so as to communicate with each other. As a result, the temperature of the coolant in the intercooler coolant circulation path 30 is prevented from rising more than necessary, so that the intercooler 31 can cool the compressed intake air from the supercharger compressor. It is possible to secure the original function (cooling action) 31 and also to cool the throttle valve 33.

  In addition, this invention is not limited only to the said embodiment, It can change suitably in the range equivalent to the claim and the said range.

  (1) In the above embodiment, an example is given in which the water pump 4 installed in the engine coolant circulation path 20 is a mechanical water pump. However, the present invention is not limited to this, for example, an electric motor pump. It is also possible to use a water pump.

  (2) In the above-described embodiment, an example in which a part of the intercooler coolant circulation path 30 is inserted into the throttle valve 33 is described. However, the present invention is not limited to this, and for example, the intercooler coolant circulation The present invention can also be applied to a case where a part of the passage 30 is not inserted into the throttle valve 33.

  (3) In the above embodiment, an example in which the opening / closing operation of the electromagnetic valve 43 is controlled by the ECU 100 is described, but the present invention is not limited to this. For example, the electromagnetic valve 43 shown in the above embodiment can be replaced with a thermostat 50 as shown in FIG.

  Such a thermostat 50 can be operated in the same manner as in the above embodiment. For example, the thermostat 50 includes a thermo actuator 51 as a control unit and a valve body 52. The thermoactuator 51 senses the coolant temperature on the intercooler coolant circulation path 30 side in the introduction path 41, and slides in the direction in which the thermoactuator 51 pulls the valve body 52 when the coolant temperature is equal to or less than the threshold value Tx. While the introduction path 41 is opened, when the coolant temperature exceeds the threshold value Tx, the thermoactuator 51 slides the valve body 52 in the pushing direction to close the introduction path 41.

  In the case of this embodiment, the temperature sensor 35 and the control system (ECU 100) used in the above embodiment are not necessary, so that the engine cooling device can be configured at a relatively low cost.

  (4) FIG. 3 shows still another embodiment of the present invention. In this embodiment, similarly to the above (3), the electromagnetic valve 43 shown in the embodiment of FIG. 1 is replaced with a thermostat 50, and a check valve 55 is further installed in the reflux path 42.

  The check valve 55 prevents the backflow of the coolant flowing through the reflux path 42 (the coolant returning from the engine coolant circulation path 20 to the intercooler coolant circulation path 30).

  When such a check valve 55 is installed in the reflux path 42, the coolant cannot be introduced from the engine coolant circulation path 20 to the intercooler coolant circulation path 30 unless the check valve 55 is opened even if the thermostat 50 is opened. .

  Therefore, the opening condition of the check valve 55 here will be described. In the first place, generally, when the engine is cold started, the engine speed is set to a first idling speed higher than the normal idling speed, and the coolant temperature in the engine coolant circulation path 20 is set to a warm-up completion temperature (for example, about 88 ° C.). If the temperature rises to the same temperature as that of the compressed intake air by the turbocharger compressor (for example, about 60 ° C.), the engine speed gradually decreases from the first idling speed to the normal idling speed. Become.

  Thus, when the engine speed decreases from the first idling speed to the normal idling speed after the engine is cold-started, the coolant temperature in the engine coolant circulation path 20 becomes the temperature of the compressed intake air (for example, about 60.degree. C.). If this happens, the intercooler 31 cannot cool the compressed intake air. That is, it can be said that the original function (cooling action) of the intercooler 31 is lost.

  Therefore, when the engine speed decreases from the first idling speed to the normal idling speed after the cold start of the engine, the suction pressure of the electric water pump 34 installed in the intercooler coolant circulation path 30 is used. The check valve 55 is set to be closed. To do so, the suction pressure of the electric water pump 34 is previously smaller than the coolant discharge pressure of the mechanical water pump 4 during the first idling rotation, and the mechanical water during the normal idling rotation of the engine. What is necessary is just to set larger than the cooling fluid discharge pressure of the pump 4. FIG.

  With this setting, the check valve 55 is opened while the engine speed is equal to the first idling speed after the thermostat 50 is opened due to the cold start of the engine, so the engine coolant circulation path 20 and the intercooler The coolant is circulated with the coolant circulation path 30. However, when the engine speed decreases from the first idling speed to the normal idling speed, the check valve 55 is closed and the coolant is recirculated from the intercooler coolant circulation path 30 to the engine coolant circulation path 20. Therefore, even if the thermostat 50 is open, the coolant cannot be introduced from the engine coolant circulation path 20 to the intercooler coolant circulation path 30. If it becomes like this, since a cooling fluid will circulate in the intercooler cooling fluid circulation path 30, and the said cooling fluid will be cooled by the radiator 32, the intercooler 31 cools the compression intake air by a supercharger compressor. Thus, the original function (cooling action) of the intercooler 31 can be secured.

  The present invention supplies an engine coolant circulation path for taking out and returning the coolant of an engine with a supercharger to the outside, and a water-cooled intercooler for cooling the compressed intake air from the turbocharger compressor. The present invention can be suitably used for an engine cooling device that enables the coolant to circulate independently in each of the intercooler coolant circulation paths through which the coolant is circulated.

4 Water pump 5 Heater core 6 Radiator 7 Thermostat 13 Block-side water jacket (engine coolant circulation path)
14 Head side water jacket (engine coolant circulation path)
21 Heater passage (engine coolant circulation path)
22 Radiator passage (engine coolant circulation path)
23 Auxiliary machine passage (engine coolant circulation path)
DESCRIPTION OF SYMBOLS 30 Intercooler coolant circulation path 31 Water-cooled intercooler 32 Radiator 33 Throttle valve 34 Water pump 35 Temperature sensor 41 Introduction path 42 Recirculation path 43 Solenoid valve 100 ECU

Claims (8)

Coolant supplied to the engine coolant circulation path for extracting and returning the coolant of the engine with the supercharger to the outside and the water-cooled intercooler for cooling the compressed intake air from the turbocharger compressor circulates An engine cooling device that enables the coolant to circulate independently with each of the intercooler coolant circulation paths,
An introduction path for enabling introduction of coolant from the engine coolant circulation path to the intercooler coolant circulation path;
A return path for allowing the coolant to return from the intercooler coolant path to the engine coolant path;
A valve body for changing the coolant flow rate in the introduction path;
An engine cooling device comprising: a control unit that opens the valve body when a coolant temperature in the intercooler coolant circulation path is equal to or lower than a predetermined threshold value. The engine cooling device according to claim 1, wherein
The engine cooling device, wherein the control unit closes the valve body when a coolant temperature in the intercooler coolant circulation path exceeds the threshold value. The engine cooling device according to claim 1 or 2,
The lower limit value of the threshold is a temperature higher than the coolant temperature of the intercooler coolant circulation path when moisture contained in the compressed intake air from the supercharger compressor adheres to the outer surface of the intercooler and freezes. The cooling target temperature of the compressed intake air from the supercharger compressor is set to a temperature that is equal to or lower than the coolant temperature that can be cooled by the intercooler, and is set in a range from the lower limit value to the upper limit value. An engine cooling device characterized by that. In the engine cooling device according to any one of claims 1 to 3,
The intercooler coolant circulation path is installed in the throttle valve so that heat can be exchanged with the throttle valve attached to the engine with the coolant of the intercooler coolant circulation path. An engine cooling device characterized by. The engine cooling device according to any one of claims 1 to 4,
The engine cooling device according to claim 1, wherein a radiator for exchanging heat between the coolant in the intercooler coolant circulation path and the outside air is installed in the intercooler coolant circulation path. The engine cooling device according to any one of claims 1 to 5,
The engine cooling apparatus according to claim 1, wherein a water pump is provided in each of the engine coolant circulation path and the intercooler coolant circulation path, and the water pump in the intercooler coolant circulation path is electrically operated. The engine cooling device according to any one of claims 1 to 6,
The valve body is an electromagnetic valve,
The controller recognizes the coolant temperature of the intercooler coolant circulation path based on the input of an output signal from a temperature sensor that detects the coolant temperature of the intercooler coolant circulation path, and the recognition result An engine cooling apparatus characterized by being an ECU that controls the opening / closing operation of the electromagnetic valve in comparison with the threshold value. The engine cooling device according to any one of claims 1 to 6,
The controller is a thermoactuator that senses the coolant temperature of the intercooler coolant circulation path and opens the valve body when the sensing result is equal to or less than the threshold value.
The engine cooling device, wherein the thermoactuator and the valve body constitute a thermostat.

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