JP2010196493A - Cooling device for egr cooler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling device for an EGR cooler forming the cooling water circulating passage of the EGR cooler, not requiring additional components and a significant change of the cooling water circulating passage of the existing EGR cooler, and facilitating maintenance of cooling water. <P>SOLUTION: Two heat exchangers, i.e., a main radiator 22 and a sub radiator 24, are formed across a partitioning plate 26 in the same casing, and the cooling water circulated in an engine is cooled by the main radiator. After that, cooling water output from the main radiator 22 and cooling water circulated in the EGR cooler 2 are concurrently introduced into the same water pump 8, and a part of the cooling water discharged from the water pump 8 is transferred to the engine and circulated in the engine. Meanwhile, the rest of the cooling water discharged from the water pump is transferred to the sub radiator and cooled again, and the cooling water output from the sub radiator is sent to the EGR cooler and circulated in the EGR cooler, thereby cooling exhaust gas. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cooling device for an EGR cooler that forms a cooling water circulation path for the EGR cooler.

Conventionally, the EGR cooler is used to cool exhaust gas exhausted from the engine and return it to the engine, but the cooling water used for this EGR cooler is also used as the engine cooling water. A common radiator exchanged heat with the outside air to lower the temperature of the cooling water.
In recent years, with an increase in the EGR (exhaust gas recirculation) rate, the performance of the EGR cooler has been demanded. For this reason, the heat exchange performance is improved by improving the body structure of the EGR cooler, and the flow path of the cooling water Many countermeasures such as improving efficiency have been considered.
However, if the heat exchange performance of the EGR cooler is improved, even if the cooling water flows efficiently, the temperature of the cooling water must depend on the heat exchange performance of the radiator, and the heat exchange performance that can sufficiently cool the engine and the EGR cooler is maintained. Is getting harder.

Therefore, in order to secure cooling water at a temperature that can sufficiently exchange heat with the EGR cooler, an EGR cooler cooling sub-radiator is provided separately from the main radiator without relying on the cooling water from the main radiator for the engine. A system for cooling the EGR cooler stably without applying a load to the main radiator has been considered.
By installing the separate EGR cooler cooling sub-radiator, it is possible to stably supply cooling water at a temperature lower than the cooling water of the main radiator, and to achieve the heat exchange performance of the enhanced EGR cooler. It became possible.

On the other hand, a heat exchanger is disclosed in which an engine radiator and an EGR cooler cooling sub-radiator are thermally coupled.
For example, as shown in FIG. 6, an EGR device described in Patent Document 1 is provided with an EGR cooler 85 in an EGR passage 84 that branches from an exhaust passage 82 and reaches an intake passage 83, and an engine cooling system (an engine 81 and an engine radiator). 86 is connected via an engine cooling water pump 90) and is connected to the EGR cooler 85 via a hose and a pump 89 to thermally connect the EGR radiator 87 and the EGR cooler 85 thermally. By combining, the cooling capacity of the EGR cooler 85 is increased.

Moreover, the heat exchanger of patent document 2 is comprised by the 1st core part and the 2nd core part which allow the cooling water of a different temperature to pass through the core part of a heat exchanger, and the tube located in the outermost end is rapidly. It is intended to prevent a significant temperature change and to prevent the external influence due to the thermal stress.
In addition, the heat exchanger described in Patent Document 3 is a unit in which two types of heat exchangers, a first radiator and a second radiator, are integrated, and the assembly workability is improved by this heat exchanger. It is.

JP 2003-278608 A JP 2004-278867 A JP 2002-115991 A

Now, when installing the above-mentioned conventional separately installed EGR radiator, it is necessary to secure the respective installation locations together with the engine radiator, but it is difficult to store them in the engine room of the vehicle. Even if it can be stored, it is necessary to consider the installation location in advance because it may affect the heat exchange performance in the vicinity of other radiators and after the condenser.
In addition, the cooling water circulation path of the EGR cooler cooling sub-radiator forms a circulation path different from the cooling water circulation path of the main radiator, so it is necessary to install a water pump or a reserve tank separately. There is a problem of how to secure.

In addition, when adding a cooling water circulation path separately, problems such as an increase in the number of parts, an increase in cost, or an increase in the number of installation work are expected, and the amount of cooling water can be confirmed or replaced due to deterioration. As for the maintenance, there is a problem that it is necessary to perform maintenance separately because it is a separate circuit.
Further, the EGR device described in Patent Document 1 has a structure in which pumps are separately provided for the engine and the EGR device, and there is a problem of increasing the number of parts and securing the installation location of each pump. About the heat exchanger of patent document 2 and patent document 3, there is no indication about the circulation path of cooling water.

  The present invention has been made to solve the above-mentioned problems, and it is not necessary to change the cooling water circulation path of the conventional EGR cooler or add parts, and the EGR cooler facilitates cooling water maintenance. An object of the present invention is to provide a cooling device.

  In order to solve the above technical problems, an EGR cooler cooling apparatus according to the present invention includes an EGR cooler 2 that cools the exhaust gas of the engine 4 and cooling water that circulates in the engine as shown in FIG. In the cooling device for an EGR cooler having a main radiator 22 for cooling the cooling water and a sub-radiator 24 for cooling the cooling water transferred to the EGR cooler, two of the main radiator 22 and the sub-radiator 24 are provided in the same housing. A heat exchanger is formed across the partition plate 26, and the cooling water circulated in the engine is cooled by the main radiator, and then the cooling water output from the main radiator 22 and the EGR cooler 2 are circulated. The cooling water is guided into the same water pump 8 and a part of the cooling water discharged from the water pump 8 is transferred to the engine. While circulating inside, the remaining cooling water discharged from the water pump is transferred to the sub-radiator and cooled again, and the cooling water output from the sub-radiator is sent to the EGR cooler and circulated to the engine. The exhaust gas is cooled by circulating in the EGR cooler at a water temperature lower than the water temperature.

  The cooling device for the EGR cooler according to the present invention is provided with the first valve 60 in the circulation path of the cooling water circulating in the engine 4, and when the temperature of the cooling water circulating in the engine is low, One of the valves 60 is opened and circulated in the circulation path in the engine as it is. When the cooling water in the engine reaches a set temperature or higher, the other valve is opened and the cooling water circulating in the engine is sent to the main radiator 22. The flow is switched to the flow to be transferred, and the cooling water cooled by the main radiator 22 is transferred to the circulation path in the engine via the water pump 8.

  The cooling device for the EGR cooler according to the present invention is provided with a second valve 66 in the cooling water circulation path for transferring the remaining cooling water discharged from the water pump 8, and the temperature of the cooling water discharged from the water pump. When the temperature is low, one of the second valves 66 is opened and transferred to the circulation path in the EGR cooler, and when the temperature of the cooling water discharged from the water pump 8 exceeds the set temperature, the other The flow is switched to the flow to be transferred to the sub-radiator 24 by opening the valve, and the cooling water cooled by the sub-radiator 24 is transferred to the EGR cooler 2.

  The cooling device for the EGR cooler according to the present invention is provided with a reserve tank 42 that is connected to the main radiator 22 and replenishes cooling water, and the cooling water replenished by the reserve tank is supplied from the cooling water outlet of the main radiator 22 to the above. In this configuration, the water is supplied to the sub-radiator 24 via the water pump 8.

According to the cooling device for an EGR cooler according to the present invention, a part of the cooling water discharged from the water pump is transferred to the engine and circulated in the engine, while the remaining cooling water discharged from the water pump is sub-radiator. The cooling water output from the sub-radiator is sent to the EGR cooler, and the exhaust gas is cooled by circulating through the EGR cooler. No need to change the location, contributing to resource savings and labor savings. Also, since two types of heat exchangers can be manufactured in the same process, the manufacturing cost can be reduced and the number of parts can be reduced because only one water pump is required. As a result, the installation location can be easily secured and the maintenance can be easily performed.
Furthermore, since the cooling water cooled by the main radiator is cooled again by the sub radiator for cooling the EGR cooler and the temperature of the cooling water is further lowered, the cooling water having a low temperature can be supplied to the EGR cooler. There is an effect that the heat exchange efficiency of the cooler is improved.

  According to the cooling device for an EGR cooler according to the present invention, the first valve is provided in the circulation path of the cooling water circulating in the engine. When the temperature of the cooling water circulating in the engine is low, the first valve Since the configuration in which one of the valves is opened and the circulation path in the engine is circulated as it is is adopted, there is an effect that the engine can be properly cooled when starting the engine and the engine can be started well.

  According to the cooling device for an EGR cooler according to the present invention, when the second valve is provided in the cooling water circulation path for transferring the remaining cooling water discharged from the water pump, and the temperature of the cooling water discharged from the water pump is low. Has adopted a configuration in which one of the second valves is opened and transferred to the circulation path in the EGR cooler, so that the EGR cooler can be properly cooled when the engine is started, and the exhaust gas can be properly cooled. The engine can be started well.

  According to the cooling device for an EGR cooler according to the present invention, a reserve tank that is connected to the main radiator and replenishes cooling water is provided, and the cooling water replenished by the reserve tank is supplied to the sub-radiator. Since only one reserve tank for supplying the main radiator and the sub-radiator is required, the number of parts is reduced, the installation location can be easily secured, and the maintenance can be easily performed.

It is a figure which shows the cooling device of the EGR cooler which concerns on embodiment of this invention. It is a figure which concerns on embodiment and shows the flow of the cooling water of the circulation path of the cooling water immediately after engine starting. It is a figure which shows the circulation path of the cooling water which concerns on embodiment and cools only the cooling water of an EGR cooler. It is a figure which shows the circulation path of the cooling water which concerns on embodiment and cools only the cooling water of an engine. It is a figure which shows the circulating path of the cooling water which concerns on embodiment and cools both the cooling water of an engine and the cooling water of an EGR cooler. It is a figure which shows the EGR apparatus which concerns on a prior art example.

Embodiments of a cooling device for an EGR cooler according to the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic view of a cooling device for an EGR cooler including a vehicle engine.
The cooling device includes an EGR cooler 2, an engine 4, a radiator 6, a water pump 8, a cooling water circulation path 10, and the like.

The EGR cooler 2 exchanges heat between exhaust gas from the engine 4 and cooling water (refrigerant). The EGR cooler 2 is provided with a cooling water inlet 12, a cooling water outlet 14, an exhaust gas inlet 16 and an exhaust gas outlet 18, and the exhaust gas is cooled by the cooling water circulating in the EGR cooler 2.
A cooling water circulation path 20 that circulates in the engine 4 for cooling the engine 4 is formed in the engine 4.

In the radiator 6, two radiators, that is, a main radiator 22 for cooling the engine and a sub-radiator 24 for cooling the EGR cooler are integrally formed in the same casing.
The radiator 6 has upper tanks 28 and 29 each having a partition plate 26 for dividing the flow of the cooling water in the upper and lower portions of a core (a radiator pipe through which the cooling water passes) having a structure similar to that of a general radiator. The lower tanks 30 and 31 are connected, and two independent heat exchangers 32 and 33 are incorporated.

  The upper tanks 28 and 29 of the heat exchangers 32 and 33 are provided with cooling water inlets 34 and 35, respectively, and the lower tanks 30 and 31 are provided with cooling water outlets 36 and 37, respectively. The cooling water flows through the inside. As described above, the radiator 6 is configured such that the main radiator 22 and the sub radiator 24 are integrally formed with the partition plate 26 interposed therebetween.

  Further, the upper tanks 28 and 29 and the lower tanks 30 and 31 of the same radiator 6 are divided so that the cooling water flows in two systems, and the main radiator 22 for engine cooling and the sub-radiator 24 for cooling the EGR cooler are divided. Two independent heat exchangers 32 and 33 are formed, and each is provided with a cooling water circulation path.

  Further, a water supply port 40 is provided in the upper tank 28 of the main radiator 22, and this water supply port 40 is connected to a reserve tank 42 through a pipe so that cooling water can be supplied from the reserve tank 42. On the other hand, drain caps 44 and 45 for maintenance are respectively attached to the lower tanks 30 and 31 of both heat exchangers 32 and 33 so that maintenance of cooling water can be performed in the same manner as a general radiator. .

  Here, the reserve tank 42 is connected to the upper tank 28 of the main radiator 22. However, the main radiator 22 for a normal engine first becomes a high temperature, and the coolant supplied from the reserve tank 42 to the main radiator 22 is It is transferred to the upper tank 29 of the sub radiator 24 via the cooling water outlet 36 and the water pump 8. For this reason, it is not necessary to separately provide a reserve tank dedicated to the sub-radiator 24, and cooling water can be supplied to both the main radiator 22 and the sub-radiator 24 with only one reserve tank 42.

  In the radiator 6, the ratio of the capacity of the main radiator 22 for cooling the engine and the sub-radiator 24 for cooling the EGR cooler is such that the amount of heat released for cooling the engine 4 and the amount of heat released for cooling the exhaust gas in the EGR cooler 2. Set the optimal ratio using as a guide.

  The water pump 8 has three suction ports 46, 47, and 48. The rotor (impeller) inside the pump is a single pump, and the cooling water sucked from each suction port is contained in the pump. Are mixed and discharged from the two discharge ports 50 and 51. The discharge port 50 is connected to the circulation path of the EGR cooler 2, and the discharge port 51 is connected to the circulation path 20 of the engine 4. The water pump 8 circulates and drives the cooling water of the cooling water circulation paths 10 of the engine 4 and the EGR cooler 2.

The water pump 8 provided in the cooling water circulation path 10 includes a circulation path 20 for cooling the engine 4, a cooling water circulation path 52 for transferring cooling water from the main radiator 22 to the water pump 8, and cooling to the EGR cooler. A cooling water circulation path 54 for transferring water, a cooling water circulation path 56 for transferring cooling water to the main radiator 22 for cooling the engine, and a cooling water circulation path 58 for transferring cooling water to the sub-radiator 24 for cooling the EGR cooler are connected. .
As described above, the single water pump 8 circulates both the circulation path related to the engine 4 and the circulation path related to the EGR cooler 2.

  In the middle of the coolant circulation path 56 to the main radiator 22 for cooling the engine, a first valve 60 that automatically opens and closes the valve by thermostat control or temperature control similar to that of the conventional radiator is installed. The valve 60 is a three-way valve having one inlet 62 and two outlets 64 and 65, and the flow is switched to one of the outlets under control. Here, the valve 60 opens the valve of the outlet 64 (the valve of the outlet 65 is closed) when the cooling water of the engine 4 reaches a certain set temperature or more, and the cooling water circulating in the engine 4 is used as a main radiator for cooling the engine. The cooling water is cooled by heat exchange.

  A second valve 66 that automatically opens and closes the valve by thermostat control or temperature control is also installed in the middle of the cooling water circulation path 58 to the sub-radiator 24 for cooling the EGR cooler. The second valve 66 is also a three-way valve having one inlet 68 and two outlets 69 and 70, and the flow is switched to one of the outlets under control. When the cooling water from the EGR cooler 2 reaches a set temperature or higher, the valve 66 opens the valve of the outlet 69 (closes the valve of the outlet 70), and the flow toward the EGR cooler 2 is sub-radiator for cooling the EGR cooler. Switch to flow towards 24. Then, the cooling water is cooled by heat exchange by the sub radiator 24 and then transferred to the circulation path in the EGR cooler 2 via the cooling water circulation path 54.

FIG. 2 shows the flow of the cooling water in the cooling water circulation path 10 immediately after the engine is started.
Usually, since the temperature of the cooling water is low immediately after the engine 4 is started, the valves 60 and 66 are switched to a low temperature state. For this reason, the outlet 65 of the first valve 60 is opened (the outlet 64 is closed), and the outlet 70 of the second valve 66 is opened (the outlet 69 is closed). Then, the cooling water of the engine 4 circulates in the circulation path 20 via the water pump 8, while the cooling water of the EGR cooler 2 circulates in the cooling water circulation paths 58 and 54, and is supplied to the main radiator 22 and the sub radiator 24. Cooling water flow is avoided.

  FIG. 3 shows a cooling water circulation path 10 that cools only the cooling water of the EGR cooler 2. When the cooling water that has passed through the EGR cooler 2 reaches a certain set temperature or higher, the valve (thermostat control) of the outlet 69 of the second valve 66 toward the sub-radiator 24 for cooling the EGR cooler opens, and the cooling water is supplied to the cooling water circulation path. It is transferred to the sub-radiator 24 via 58.

Then, the cooling water heat-exchanged and cooled by the sub-radiator 24 is transferred to the EGR cooler 2 via the cooling-water circulation path 54 and exchanged with the exhaust gas in the EGR cooler 2, and further cooled. A flow that is transferred to the water pump 8 via the water circulation path 58 is formed, and the EGR cooler 2 and the sub radiator 24 are circulated via the cooling water circulation paths 54 and 58.
On the other hand, for the engine 4, the outlet 65 of the first valve 60 is opened, and the cooling water of the engine 4 circulates through the circulation path 20 via the water pump 8.

  FIG. 4 shows a cooling water circulation path 10 for cooling only the cooling water of the engine 4. When the cooling water circulating in the engine 4 reaches a certain set temperature or higher, the valve (thermostat control) of the outlet 64 toward the main radiator 22 of the first valve 60 is opened, and the cooling water from the engine 4 is supplied to the cooling water circulation path 56. To the main radiator 22 via

And the cooling water heat-exchanged and cooled by this main radiator 22 forms the flow transferred to the water pump 8 via the cooling water circulation path 52, and thus passes through the cooling water circulation paths 56, 52. The engine 4 and the main radiator 22 are circulated.
On the other hand, for the EGR cooler 2, the valve at the outlet 70 of the second valve 66 is opened, and the cooling water of the EGR cooler 2 circulates through the cooling water circulation paths 58 and 54 via the water pump 8.

  FIG. 5 shows a cooling water circulation path 10 that cools both the cooling water of the engine 4 and the cooling water of the EGR cooler 2. When both the cooling waters reach a certain set temperature or higher, the cooling water circulates through the radiators 22 and 24 as shown in FIG. 5 and efficiently cools the exhaust gas in the engine 4 and the EGR cooler 2.

  In this case, the cooling water from the EGR cooler 2 is transferred to the water pump 8 via the cooling water circulation path 58, and the cooling water cooled by the main radiator 22 is transferred to the water pump 8 via the cooling water circulation path 52. Then, they merge in the water pump 8. The cooling water from the EGR cooler 2 merged in the water pump 8 is mixed with the cooling water from the main radiator 22 and the temperature is lowered.

  Thereafter, a part of the cooling water output from the water pump 8 is discharged from the discharge port 51 and transferred to the circulation path 20 in the engine 4 to circulate in the engine. Thereafter, since the valve at the outlet 64 of the first valve 60 is opened, the cooling water is transferred to the main radiator 22 via the cooling water circulation path 56 and cooled.

Further, the remainder of the cooling water output from the water pump 8 is discharged from the discharge port 50, and the valve at the outlet 69 of the second valve 66 is open, so that the EGR cooler cooling is performed via the cooling water circulation path 58. The sub-radiator 24 is transferred to the sub-radiator 24 and cooled again.
Then, the cooling water cooled again by the sub radiator 24 is transferred to the circulation path in the EGR cooler 2 via the cooling water circulation path 54.

For this reason, the cooling water sent to the EGR cooler 2 can be supplied to the EGR cooler at a lower temperature than the cooling water cooled by the main radiator 22, and the cooling performance of the EGR cooler 2 can be improved. .
Note that the temperature of the cooling water used in the EGR cooler 2 is desired to be lower than the temperature of the cooling water used in the engine 4, thereby improving the performance of the EGR cooler 2. it can.

Therefore, according to the above-described embodiment, by using a heat exchanger in which two types of heat exchangers, a main radiator and a sub-radiator for cooling the EGR cooler, are used, the installation location of the heat exchanger is changed from the conventional place. Therefore, there is no need to add mounting parts on the vehicle side for installation, and the installation process does not need to be changed. This contributes to resource saving and labor saving.
In addition, when manufacturing heat exchangers, two types of heat exchangers can be manufactured in the same process, so manufacturing costs can be reduced, and conventionally, water pumps and reserve tanks that had to be installed separately for each radiator have been installed. Only one unit can be operated, the number of parts is reduced, and it is not necessary to secure a place for installing these parts.

Furthermore, the cooling water cooled by the main radiator is mixed with the cooling water from the EGR cooler to lower the temperature of the cooling water, and the cooling water whose temperature has been lowered is cooled again by the sub radiator 24 for cooling the EGR cooler, Since the temperature is further lowered, low-temperature cooling water can be supplied to the EGR cooler, so that the heat exchange efficiency of the EGR cooler is improved.
Further, since the cooling water from the main radiator and the cooling water from the EGR cooler are mixed in the circulation process by one water pump, maintenance can be easily performed without having to be performed separately.

2 EGR cooler 4 Engine 6 Radiator 8 Water pump 10 Cooling water circulation path 12 Cooling water inlet 14 Cooling water outlet 16 Exhaust gas inlet 18 Exhaust gas outlet 22 Main radiator 24 Sub-radiator 28, 29 Upper tank 30, 31 Lower tank 32, 33 Heat exchanger 34, 35 Cooling water inlet 36, 37 Cooling water outlet 40 Water supply port 42 Reserve tank 46, 47, 48 Suction port 50, 51 Discharge port 52, 54, 56, 58 Cooling water circulation path 60 First valve 62 Inlet 64, 65 outlet 66 second valve 68 inlet 69, 70 outlet

Claims (4)

An EGR cooler cooling apparatus comprising: an EGR cooler that cools engine exhaust gas; a main radiator that cools cooling water circulating in the engine; and a sub-radiator that cools cooling water transferred to the EGR cooler.
In the same housing, two heat exchangers of the main radiator and the sub radiator are formed with a partition plate interposed therebetween,
After cooling the cooling water circulated in the engine with the main radiator, the cooling water output from the main radiator and the cooling water circulated in the EGR cooler are both guided into the same water pump,
A part of the cooling water discharged from the water pump is transferred to the engine and circulated in the engine, while the remaining cooling water discharged from the water pump is transferred to the sub-radiator and cooled again. A cooling device for an EGR cooler, characterized in that cooling water output from a sub-radiator is sent to the EGR cooler and circulated in the EGR cooler to cool the exhaust gas.   A first valve is provided in the cooling water circulation path circulating in the engine, and when the temperature of the cooling water circulating in the engine is low, one valve of the first valve is opened and the engine is left as it is. When the circulating water is circulated and the cooling water in the engine reaches the set temperature or higher, the other valve is opened and the cooling water circulating in the engine is switched to the flow to transfer to the main radiator, and the cooling water cooled by this main radiator is supplied. The cooling device for an EGR cooler according to claim 1, wherein the cooling device is transferred to a circulation path in the engine via the water pump.   A second valve is provided in the cooling water circulation path for transferring the remaining cooling water discharged from the water pump, and when the temperature of the cooling water discharged from the water pump is low, one of the second valves is The valve is opened and transferred to the circulation path in the EGR cooler. When the temperature of the cooling water discharged from the water pump exceeds the set temperature, the other valve is opened and the flow is switched to the sub-radiator. The cooling device for an EGR cooler according to claim 1 or 2, wherein the cooling water cooled by the sub-radiator is transferred to the EGR cooler.   A reserve tank that is connected to the main radiator and replenishes cooling water is provided, and the cooling water replenished by the reserve tank is supplied from the cooling water outlet of the main radiator to the sub radiator via the water pump. The cooling device for an EGR cooler according to claim 1, 2 or 3.

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