JP2008151035A - Cooling device of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce sliding resistance of an engine and to cool engine oil at the same time. <P>SOLUTION: In a main cooling circuit 11 provided with the engine 12, a radiator 13 and a thermostat 14, cooling fluid circulates between the engine 12 and the radiator 13 when a valve of the thermostat 14 is opened. In the main cooling circuit 11, a first bypass passage 16 for bypassing the radiator 13 and communicating with inside of the thermostat 14 wherein a cooling fluid always circulates between the engine 12 and the first bypass passage 16 and a second bypassing passage 17 for bypassing the radiator 13 and communicating with the thermostat 14 wherein the cooling fluid circulates between the engine 12 and the second bypassing passage 17 and its circulation is blocked when a valve of the thermostat 14 is opened. An oil heat exchanger 21 is provided for the second bypass passage 17. A communication passage 22 and a control valve 23 for circulating the cooling fluid between the engine 12 and the oil heat exchanger 21 when the engine is hot are provided for the oil heat exchanger 21. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine cooling apparatus.

  Conventionally, an engine cooling device is known (see, for example, Patent Document 1). This engine cooling device includes a cooling circuit in which an engine, a radiator, and a thermostat are interposed. And when the engine is warm and hot, the thermostat is opened, the coolant is circulated through the engine to cool the engine, and the coolant heated by the cooling is led to the radiator and cooled by the outside air, Come back to the engine.

Further, the cooling circuit is provided with a bypass passage that bypasses the radiator and communicates with the inside of the thermostat so that the coolant circulates between the engine and the engine at all times. An idle speed control valve is interposed in the bypass circuit. The idle speed control valve is always heated by the coolant and is not frozen when the temperature of the outside air is low.
JP 2001-115836 A

  Consider installing a heat exchanger for exchanging heat between the coolant and oil in the bypass passage instead of the idle speed control valve. In this case, when the engine is cold, the oil is heated in the heat exchanger by exchanging heat with the coolant heated through the engine. Thereby, the temperature of low temperature oil can be raised. This is preferable from the viewpoint of engine efficiency.

  Further, when the engine is hot, the oil is cooled by exchanging heat with the coolant in the heat exchanger. Thereby, the temperature of the oil that has become too high can be lowered, and the oil can be kept at an appropriate temperature.

  Here, when the engine is warm, it is desirable not to cool the oil in order to keep the temperature of the oil at an appropriate temperature (relatively high temperature) and to keep the viscosity of the oil moderately low.

  However, as described above, when the heat exchanger is provided in the bypass passage, the oil is cooled by exchanging heat with the coolant in the heat exchanger even when the engine is warm.

  The present invention has been made in view of this point, and an object of the present invention is to achieve both reduction in engine sliding resistance and oil cooling.

  The first invention is provided with an engine, a radiator, and a thermostat that closes when the engine is cold and opens when the engine is warm and hot, and when the thermostat is opened, the coolant is connected to the engine. A cooling circuit that circulates to and from the radiator, and the cooling circuit is provided with a first bypass passage that bypasses the radiator and communicates with the inside of the thermostat and constantly circulates the coolant between the engine and the engine. An engine cooling device, wherein the cooling circuit bypasses the radiator and communicates with the thermostat, and when the thermostat is closed, coolant circulates between the engine and the thermostat. A second bypass passage for interrupting the circulation when the valve is opened is further provided in the second bypass passage for heat exchange of the coolant with oil. The heat exchanger is provided with circulation means for circulating a coolant between the engine and the heat exchanger when the engine is hot. is there.

  Thereby, when the engine is cold, the coolant circulates between the engine and the engine in the second bypass passage, so that the oil exchanges heat with the coolant that is heated by flowing through the engine in the heat exchanger of the second bypass passage. Heated.

  In addition, when the engine is warm, the circulation of the coolant to and from the engine is blocked in the second bypass passage, and the coolant does not flow, so that the oil is not cooled in the heat exchanger of the second bypass passage, The temperature is maintained at an appropriate temperature (relatively high temperature), and the viscosity of the oil is moderately low.

  Furthermore, the heat exchanger is provided with a circulation means for circulating the coolant between the engine and the heat exchanger when the engine is hot, so that when the engine is hot, the oil exchanges heat with the coolant in the heat exchanger. And cooled.

  As described above, both reduction in engine sliding resistance and oil cooling can be achieved.

  According to a second invention, in the first invention, the first bypass passage is provided with a device that constantly requires heat exchange with the coolant, and the second bypass passage is provided only with the heat exchanger. It is characterized by being provided.

  Here, since the coolant constantly circulates between the engine and the engine in the first bypass passage, the device of the first bypass passage that constantly requires heat exchange with the coolant is constantly exchanging heat with the coolant. Reduction of sliding resistance and oil cooling can both be achieved.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the circulation means is provided in the communication path, the communication path communicating the heat exchanger and the first bypass path or the thermostat, and the communication path. And an on-off valve that opens when the engine is hot.

  Thereby, a circulation means is realizable with a simple structure.

  According to the present invention, when the engine is cold, the coolant circulates between the engine and the engine in the second bypass passage. Therefore, in the heat exchanger of the second bypass passage, the oil flows through the engine and is heated. Heated by heat exchange. In addition, when the engine is warm, the circulation of the coolant to and from the engine is blocked in the second bypass passage, and the coolant does not flow, so that the oil is not cooled in the heat exchanger of the second bypass passage, The temperature is maintained at an appropriate temperature (relatively high temperature), and the viscosity of the oil is moderately low. Furthermore, the heat exchanger is provided with a circulation means for circulating the coolant between the engine and the heat exchanger when the engine is hot, so that when the engine is hot, the oil exchanges heat with the coolant in the heat exchanger. And cooled. As described above, both reduction in engine sliding resistance and oil cooling can be achieved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a system diagram of an engine cooling apparatus 10 according to an embodiment of the present invention. In FIG. 1, the direction of circulation of engine coolant (hereinafter referred to as coolant) is indicated by arrows. As shown in FIG. 1, the engine cooling device 10 includes a main cooling circuit 11 (thick line in FIG. 1). The main cooling circuit 11 is a closed circuit in which the engine 12, the radiator 13, the thermostat 14, and the water pump 15 are connected by piping in that order in the circulation direction of the coolant. The radiator 13 is a device used to release the heat generated by the engine 12, and is located in the front part of the automobile and has a structure that cools the heated coolant with outside air. The thermostat 14 closes a thermostat valve (not shown; hereinafter referred to as a valve) when the engine is cold, stops circulation of the coolant in the main cooling circuit 11, and opens the valve when the engine is warm and hot. It is an automatic valve that causes the coolant to flow through the main cooling circuit 11. Specifically, the thermostat 14 is closed when the temperature of the coolant in the thermostat 14 is lower than a first set temperature (for example, 80 degrees), and the valve is closed when the temperature is equal to or higher than the first set temperature. It is in an open state. The water pump 15 is a pump for forcibly circulating the coolant, and is driven by the engine 12. In the main cooling circuit 11, when the water pump 15 is in operation, the coolant circulates between the engine 12 and the radiator 13 when the valve of the thermostat 14 is opened, and the water pump 15 when the valve of the thermostat 14 is closed. Even during operation, the circulation is interrupted.

  The main cooling circuit 11 is provided with a first bypass passage 16 and a second bypass passage 17. The first bypass passage 16 is diverted from between the outlet 12 a of the engine 12 and the inlet 13 a of the radiator 13 in the main cooling circuit 11, and bypasses the radiator 13 and joins in the thermostat 14. In the first bypass passage 16, during operation of the water pump 15, the coolant always circulates with the engine 12 via the main cooling circuit 11 regardless of whether the valve of the thermostat 14 is opened or closed. It is supposed to be. Since such a mechanism that the coolant always circulates regardless of the state of the valve of the thermostat 14 is already well known, detailed description thereof is omitted here.

  Moreover, the 1st bypass channel | path 16 branches into the 1st branch channel | path 16a and the 2nd branch channel | path 16b in the middle, and they are also one flow. The first branch passage 16a is provided with a hot water heater 18 using a coolant as a heat source, and the second branch passage 16b is provided with an EGR valve 19 and a throttle body 20 that require cooling. The heater 18, the EGR valve 19, and the throttle body 20 are devices that always require heat exchange with the coolant.

  The second bypass passage 17 is provided in parallel with the first bypass passage 16, and diverts from between the outlet 12 a of the engine 12 and the inlet 13 a of the radiator 13 in the main cooling circuit 11, bypassing the radiator 13 and thermostating. 14 joins. In the second bypass passage 17, when the water pump 15 is operating and the valve of the thermostat 14 is closed (that is, when the valve of the second bypass passage 17 is opened), the coolant passes through the main cooling circuit 11. When the valve of the thermostat 14 is opened (that is, when the valve of the second bypass passage 17 is closed), the circulation is performed even when the water pump 15 is in operation. It is designed to be blocked. Since a mechanism in which the coolant circulates when the valve of the thermostat 14 is closed and the circulation is blocked when the valve is opened is already well known, detailed description thereof is omitted here.

  The second bypass passage 17 is provided only with an oil heat exchanger (oil cooler) 21 for exchanging heat between the coolant and engine oil (hereinafter referred to as oil). The oil heat exchanger 21 is provided with a communication passage 22 that communicates between the oil heat exchanger 21 and the junction 16 c of the first and second branch passages 16 b in the first bypass passage 16 and the thermostat 14. It has been. A control valve 23 (corresponding to an on-off valve) is interposed in the communication path 22. The control valve 23 is closed when the engine is cold and warm, and is opened when the engine is hot. Specifically, the control valve 23 has a second set temperature at which the coolant temperature detected by a water temperature sensor 24 provided near the outlet 12a of the engine 12 of the main cooling circuit 11 is larger than the first set temperature. When the temperature is smaller than (for example, 95 degrees), the valve closing control is performed by a control device (not shown), and the valve opening control is performed when the temperature is equal to or higher than the second set temperature. The communication path 22 and the control valve 23 constitute a circulation means for circulating the coolant between the engine 12 and the oil heat exchanger 21 when the engine is hot. Thereby, a circulation means is realizable with a simple structure.

-Engine cooling system operation-
Hereinafter, the operation of the engine cooling apparatus 10 will be described. In the following description, the water pump 15 is in operation.

  When the engine is cold, the valve of the thermostat 14 is closed. At this time, in the main cooling circuit 11, the flow of the coolant between the engine 12 and the radiator 13 is blocked, and the coolant flows between the engine 12 in the bypass passages 16 and 17. Thereby, in the oil heat exchanger 21 of the second bypass passage 21, the oil flows through the engine 12 and is heated by exchanging heat with the heated coolant. In the first bypass passage 16, the heater 18, the EGR valve 19, and the throttle body 20 exchange heat with the coolant. This is the same when the engine is warm and hot.

  When the engine is warm, the valve of the thermostat 14 is open. At this time, in the main cooling circuit 11, the coolant flows between the engine 12 and the radiator 13, and in the first bypass passage 16, the coolant flows between the engine 12. Further, in the second bypass passage 17, the flow of the coolant with the engine 12 is blocked, and the coolant does not flow. For this reason, the oil is not cooled in the oil heat exchanger 21, the temperature of the oil is maintained at an appropriate temperature (relatively high temperature), and the viscosity of the oil can be suppressed to a moderately low level.

  When the engine is hot, the coolant flows between the engine 12 and the radiator 13 in the main cooling circuit 11, and the coolant flows between the engine 12 and the first bypass passage 16 in the same manner as when the engine is warm. In the second bypass passage 17, the circulation of the coolant with the engine 12 is blocked. At this time, the control valve 23 opens. As a result, the coolant remaining in the second bypass passage 17 when the engine is warm flows out from the oil heat exchanger 21 to the communication passage 22 and passes through the communication passage 22, the first bypass passage 16, and the main cooling circuit 11. To return to the engine 12. Then, the coolant circulates between the engine 12 and the oil heat exchanger 21 via the second bypass passage 17, the communication passage 22, the first bypass passage 16, and the main cooling circuit 11. For this reason, in the oil heat exchanger 21, the oil is cooled by exchanging heat with the coolant. If the cooling water in the oil heat exchanger 21 does not flow in the second bypass passage 17 in the hot engine state, the cooling water boils due to the temperature rising oil, and the deterioration of the oil is promoted. The heat exchanger 21 may be damaged, but this can be prevented beforehand by the above-described configuration.

-Effect-
As described above, according to the present embodiment, when the engine is cold, the coolant circulates between the second bypass passage 17 and the engine 12, so that the oil is exchanged in the oil heat exchanger 21 of the second bypass passage 17 with the engine. Heat is exchanged with the coolant that has flowed through 12 and heated.

  In addition, when the engine is warm, the circulation of the coolant to and from the engine 12 is blocked in the second bypass passage 17 and the coolant does not flow, so that the oil is cooled in the oil heat exchanger 21 in the second bypass passage 17. In other words, the temperature of the oil is maintained at an appropriate temperature (relatively high temperature), and the viscosity of the oil is moderately reduced.

  Furthermore, the oil heat exchanger 21 is provided with a communication path 22 and a control valve 23 for circulating the coolant between the engine 12 and the oil heat exchanger 21 when the engine is hot. In the heat exchanger 21, the oil is cooled by exchanging heat with the coolant.

  As described above, the reduction of the sliding resistance of the engine 12 and the cooling of the oil can be achieved at the same time.

  Here, since the coolant always circulates between the engine 12 in the first bypass passage 16, the heater 18, EGR valve 19, and throttle body 20 that always require heat exchange with the coolant in the first bypass passage 16. Can be made compatible with both the reduction of the sliding resistance of the engine 12 and the cooling of the oil while constantly exchanging heat with the coolant.

(Other embodiments)
In the above embodiment, the engine 12, the radiator 13, the thermostat 14, and the water pump 15 are provided in the main cooling circuit 11 in that order in the coolant circulation direction, but the order is not limited thereto.

  Moreover, in the said embodiment, although the heater 18, the EGR valve 19, and the throttle body 20 comprise the apparatus which always requires heat exchange with a cooling fluid, the apparatus is not restricted to these.

  Moreover, in the said embodiment, although only the oil heat exchanger 21 is interposed in the 2nd bypass channel 17, you may insert apparatuses other than this.

  In the above embodiment, the communication passage 22 communicates the oil heat exchanger 21 and the first bypass passage 16, but the oil heat exchanger 21 and the thermostat 14 may communicate. In this case, during operation of the water pump 15 and when the engine is hot, the coolant circulates between the engine 12 and the oil heat exchanger 21 regardless of whether the valve of the thermostat 14 is opened or closed.

  Moreover, in the said embodiment, although the on-off valve is comprised by the control valve 23, you may comprise not only this but the thermostat 25, for example, as shown in FIG. The thermostat 25 is directly attached to the oil heat exchanger 21 and closes when the engine is cold and warm and opens when the engine is hot. Specifically, the thermostat 25 is closed when the temperature of the coolant in the oil heat exchanger 21 is lower than the second set temperature, while remaining in the oil heat exchanger 21 when the engine is warm. When the coolant is heated by exchanging heat with oil and heated to a temperature equal to or higher than the second set temperature, the coolant is opened. In this case, the communication passage 22 communicates the thermostat 25 and the first bypass passage 16.

  In the above embodiment, the circulation means is constituted by the communication path 22 and the control valve 23. However, any means may be used as long as the coolant is circulated between the engine 12 and the oil heat exchanger 21 when the engine is hot. It may be configured.

  The present invention is not limited to the embodiments, and can be implemented in various other forms without departing from the spirit or main features thereof.

  As described above, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is defined by the claims, and is not limited by the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  As described above, the present invention can be applied to applications for achieving both reduction of engine sliding resistance and cooling of engine oil.

It is a systematic diagram of the cooling device of the engine concerning the embodiment of the present invention. It is a systematic diagram of an engine cooling device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine cooling device 11 Cooling circuit 12 Engine 13 Radiator 14 Thermostat 15 Water pump 16 First bypass passage 17 Second bypass passage 18 Heater (equipment)
19 EGR valve (equipment)
20 Throttle body (equipment)
21 Oil heat exchanger 22 Communication path (circulation means)
23 Control valve (circulation means, on-off valve)
25 Thermostat (circulation means, on-off valve)

Claims (3)

An engine, a radiator, and a thermostat that closes when the engine is cold and opens when the engine is warm and hot are interposed, and when the thermostat is opened, the coolant flows between the engine and the radiator. With a circulating cooling circuit,
The cooling system for an engine, wherein the cooling circuit is provided with a first bypass passage that bypasses the radiator and communicates with the inside of the thermostat and constantly circulates the coolant between the engine and the engine.
The cooling circuit bypasses the radiator and communicates with the thermostat, the coolant circulates between the engine when the thermostat is closed, and the circulation is shut off when the thermostat is opened. A bypass passage is further provided,
The second bypass passage is provided with a heat exchanger for exchanging heat between the coolant and the oil,
The engine cooling apparatus according to claim 1, wherein the heat exchanger is provided with a circulating means for circulating a coolant between the engine and the heat exchanger when the engine is hot. The engine cooling device according to claim 1,
In the first bypass passage, a device that always requires heat exchange with the coolant is interposed,
The engine cooling apparatus according to claim 1, wherein only the heat exchanger is interposed in the second bypass passage. The engine cooling device according to claim 1 or 2,
The circulation means includes a communication passage that communicates the heat exchanger with the first bypass passage or the thermostat, and an on-off valve that is interposed in the communication passage and opens when the engine is hot. Engine cooling device.

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