JP2017072091A - Vehicle cooling system - Google Patents

Abstract

An object of the present invention is to provide a vehicular cooling device capable of efficiently cooling each of the engine and the EGR cooler while avoiding the influence of each other. An electric water pump 61 is interposed between an EGR core 46b formed on a radiator 43 and a water-cooled EGR cooler 22a, 22b. The EGR core 46b, the water-cooled EGR coolers 22a, 22b, and the electric The first EGR cooling circuit 60 composed of the water pump 61 is configured by a circuit independent of the main cooling circuit 40 having the engine core 46 a formed in the radiator 43. [Selection] Figure 1

Description

  The present invention relates to a vehicular cooling device. More specifically, the present invention relates to a vehicular cooling device, while avoiding the influence of the cooling of an engine and the cooling of an EGR cooler on each other while suppressing the increase in the weight of the device. The present invention relates to a vehicle cooling device.

  Proposed a system that forms two heat exchangers, a main radiator and a sub radiator, with a partition plate in the radiator that cools the engine cooling water, and supplies the cooling water cooled by the sub radiator to the water-cooled EGR cooler (For example, refer to Patent Document 1).

  However, this apparatus is configured to introduce cooling water whose temperature has been increased by heat exchange with EGR gas in a water-cooled EGR cooler to a water pump into which engine cooling water is introduced. Therefore, the heat load of the circuit that cools the engine due to the rise in the temperature of the cooling water of the water-cooled EGR cooler when the EGR gas is recirculated in large quantities, the engine is heavily loaded, or the exhaust gas aftertreatment device is being regenerated. As a result, there is a problem that the cooling efficiency of the engine decreases.

  In particular, in a large vehicle such as a truck, a large amount of EGR gas may be recirculated in order to effectively suppress NOx contained in the exhaust gas. Cooling efficiency may decrease and the engine may not be properly cooled.

JP 2010-196493 A

  An object of the present invention is to provide a vehicular cooling device capable of efficiently cooling each other while preventing the cooling of the engine and the cooling of the EGR cooler from affecting each other while suppressing an increase in the thickness of the device. Is to provide.

  The vehicle cooling device of the present invention that achieves the above object includes a radiator that cools cooling water of an engine, a partition plate is disposed inside each of the upper tank and the lower tank of the radiator, and the radiator core of the radiator includes Divided into an engine core and an EGR core, an engine inlet and an EGR inlet are arranged in the upper tank, an engine outlet and an EGR outlet are arranged in the lower tank, and the cooling cooled by the EGR core In the vehicle cooling device configured to supply water to a water-cooled EGR cooler interposed in an EGR passage that branches from an exhaust passage and merges with an intake passage, the EGR core, the water-cooled EGR cooler, An electric water pump is interposed between the EGR core, the water-cooled EGR cooler, and the electric water pump. The first EGR cooling circuit consisting Taponpu, characterized in that it is composed of an independent circuit from the main cooling circuit having a core the engine.

  According to the vehicle cooling device of the present invention, the main cooling circuit that cools the engine and the first EGR cooling circuit that cools the water-cooled EGR cooler are configured to share one radiator, so in the water-cooled EGR cooler, Without increasing the number of radiators for cooling the EGR gas, it is possible to suppress an increase in the thickness of the apparatus. In addition, the first EGR cooling circuit that supplies the cooling water cooled by the EGR core to the water-cooled EGR cooler is provided with an electric water pump and is made independent of the main cooling circuit. The main cooling circuit can be prevented from affecting each other. Thereby, by improving the cooling efficiency in each cooling circuit, both the engine and the EGR gas can be efficiently cooled.

  In particular, the vehicular cooling device of the present invention is suitable for a large vehicle such as a truck equipped with an engine having a large number of cylinders, and even if a large amount of EGR gas is refluxed, it can be efficiently cooled. For example, in an engine of 6 cylinders or more, since EGR gas becomes large, a water-cooled EGR cooler is arranged in parallel in each of two EGR passages, or two water-cooled EGR coolers are connected in series in one EGR passage. There is something arranged. A large amount of EGR gas can be cooled by supplying cooling water to the two water-cooled EGR coolers using the electric water pump independent of the main cooling circuit in the first EGR cooling circuit independent of the main cooling circuit. it can.

It is a lineblock diagram illustrating the cooling device for vehicles of a first embodiment of the present invention. FIG. 2 is a perspective view illustrating the configuration of the radiator of FIG. 1. It is a block diagram which illustrates the cooling device for vehicles of 2nd embodiment of this invention. It is a block diagram which illustrates the cooling device for vehicles of 3rd embodiment of this invention. It is a block diagram which illustrates the modification of the cooling device for vehicles of 3rd embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 illustrates a vehicle cooling device 30 according to the first embodiment of the present invention. The vehicle cooling device 30 cools each of the engine 10, the water-cooled intercooler 13, and the water-cooled EGR coolers 22a and 22b mounted on the vehicle.

  In the engine 10, after the intake air A drawn into the intake passage 11 during driving of the vehicle is compressed by the compressor (supercharger) 12 a of the turbocharger 12 and becomes high temperature and cooled by the water-cooled intercooler 13. Then, it is supplied to the engine body 15 via the intake manifolds 14a and 14b. The intake air A supplied to the engine body 15 is mixed with fuel in the cylinder and combusted to generate heat energy, and then becomes exhaust gas G1 and is exhausted from the exhaust manifolds 16a and 16b to the exhaust passage 17, After the turbine 12b of the turbocharger 12 is driven, it is purified by an exhaust gas purification device (not shown) and then released into the atmosphere.

  More specifically, the intake air A drawn into the intake passage 11 is branched into two intake branch passages 11a and 11b, and the branched intake air A is supplied to the engine body 15 through the intake manifolds 14a and 14b. Further, the exhaust gas G1 exhausted to the exhaust passage 17 joins in the exhaust passage 17 from the two exhaust manifolds 16a and 16b via the two exhaust branch passages 17a and 17b, and drives the turbine 12b. Thus, for example, in a multi-cylinder engine 10 having six or more cylinders, each of the intake passage 11 and the exhaust passage 17 is formed in a bifurcated manner, and two intake manifolds 14 a and 14 b are provided between the intake passage 11 and the engine body 15. Since the two exhaust manifolds 16a and 16b are interposed between the exhaust passage 17 and the engine body 15, one manifold is configured to branch into three cylinders, thus complicating the manifold. Therefore, the intake pulsation (inertia) effect and the exhaust pulsation (inertia) effect can be effectively obtained.

The EGR system 20 is a system that recirculates the EGR gas G2 from the exhaust passage 17 to the intake passage 11, and the EGR gas G2 flows from the exhaust branch passages 17a and 17b to the EGR passages 21a.
, 21b, and after being cooled by each water-cooled EGR cooler 22a, 22b interposed in each of the EGR passages 21a, 21b, the EGR valves 23a, 23b are opened to open the intake branch passages 11a, 11b. Supplied. As described above, since two EGR passages 21a and 21b are provided for one engine body 15, a large amount of EGR gas G2 can be recirculated, so NOx (nitrogen oxide) contained in the exhaust gas G1. It becomes advantageous for reduction of.

  The EGR system 20 may be a low pressure type in which the EGR passages 21 a and 21 b branch from the exhaust passage 17 downstream of the turbocharger 12 in addition to the high pressure type in which the EGR passages 21 a and 21 b branch from the exhaust passage 17 upstream of the turbocharger 12.

  The vehicle cooling device 30 includes a cooling fan 31 that is connected to and driven by the crankshaft 18, a main cooling circuit 40, a sub cooling circuit 50, and a first EGR cooling circuit 60. The main cooling circuit 40, the sub cooling circuit 50, and the first EGR cooling circuit 60 are independent circuits, and in the following, the cooling water flowing through each will be distinguished from W1, W2, and W3.

  In the main cooling circuit 40, the cooling water W1 is either a mechanical water pump 41, an engine body 15, a thermostat 42, a cooling passage 44 provided with a radiator 43 or a bypass passage 45 that bypasses the cooling passage 44, In addition, the mechanical water pump 41 is circulated in this order. Therefore, the main cooling circuit 40 is a circuit in which the cooling water W1 for cooling the engine body 15 circulates.

  The sub-cooling circuit 50 is a circuit in which the cooling water W2 is independent from the main cooling circuit 40, and circulates in the order of the electric water pump 51, the sub-radiator 52, the water-cooled intercooler 13, and the electric water pump 51. Accordingly, the sub-cooling circuit 50 is a circuit through which the cooling water W2 for cooling the intake air A passing through the water-cooled intercooler 13 circulates. Note that a water-cooled condenser for cooling the air-conditioning refrigerant of the vehicle interior air conditioner may be connected to the sub-cooling circuit 50 in parallel with the water-cooled intercooler 13.

  The first EGR cooling circuit 60 is a circuit independent of the main cooling circuit 40 and the sub cooling circuit 50, and the cooling water W3 is an electric water pump 61, water-cooled EGR coolers 22a and 22b, a radiator 43, and an electric water pump 61. It is circulating in order. Accordingly, the first EGR cooling circuit 60 is a circuit through which the cooling water W3 that passes through the water-cooled EGR coolers 22a and 22b and cools the EGR gas G2 circulates.

  The mechanical water pump 41 is mechanical, and the rotational power of the engine body 15 is transmitted from the crankshaft 18 via a power transmission mechanism 19 such as an endless belt or gear mechanism, and is driven by this rotational power. .

  The thermostat 42 is disposed on the outlet side of the main body 15 of the main cooling circuit 40. The thermostat 42 has a lifter (not shown) that expands and contracts by a thermal expansion body that has the property of expanding as the temperature rises and shrinking as the temperature decreases. The flow rate of the cooling water W <b> 1 flowing through the cooling passage 44 and the bypass passage 45 is adjusted by extending and contracting the lifter according to the temperature. An electrothermal thermostat in which the lift is forcibly expanded and contracted by electric heating may be used for the thermostat 42.

As in this embodiment, the thermostat 42 is arranged on the outlet side of the engine body 15 of the main cooling circuit 40, and the water temperature of the cooling water W1 is controlled on the outlet side. It is advantageous in improving durability because it can improve the pullability and suppress the occurrence of cavitation, and is particularly suitable for large vehicles such as trucks.

  Instead of the outlet control, an inlet control in which a thermostat 42 is disposed on the inlet side of the engine body 15 of the main cooling circuit 40 can be applied. In the case of the inlet control, it is advantageous in terms of temperature adjustment of the cooling water W1 as compared with the outlet control.

  The radiator 43 is disposed on the front side of the vehicle on which the engine 10 and the vehicle cooling device 30 are mounted, and the cooling fan 31 is disposed behind the radiator 43. The radiator 43 cools the cooling water W1 and W3 passing through the inside using the vehicle speed wind and the cooling air generated by the subsequent cooling fan 31.

  FIG. 2 is a perspective view of the radiator 43. As shown in FIG. 2, the radiator 43 has partition plates 49 a and 49 b arranged inside an upper tank 47 and a lower tank 48. The radiator core 46 is divided into an engine core 46a and an EGR core 46b by the partition plates 49a and 49b. An engine inlet 47 a and an EGR inlet 47 b are disposed in the upper tank 47, and an engine outlet 48 a and an EGR outlet 48 b are disposed in the lower tank 48. The engine core 46a is configured to have a larger cooling area than the EGR core 46b.

  In the radiator 43, the cooling water W1 circulating in the main cooling circuit 40 flows in from the engine inlet 47a, is cooled by the engine core 46a, and then flows out from the engine outlet 48a, while circulating in the first EGR cooling circuit 60. The cooling water W3 to be flowed in flows from the EGR inlet 47b, is cooled by the EGR core 46b, and then flows out from the EGR outlet 48b. Since the main cooling circuit 40 for cooling the engine main body 15 and the first EGR cooling circuit 60 for cooling the water-cooled EGR coolers 22a and 22b are configured to share one radiator 43, the water-cooled EGR cooler 22a. , 22b, without increasing the number of radiators for cooling the EGR gas G2, it is possible to suppress an increase in the thickness of the vehicular cooling device 30. As a result, it is possible to save space in the engine room and further improve fuel efficiency.

  The electric water pumps 51 and 61 are pumps that are driven by electric power generated by an alternator (not shown), and their arrangement positions may be anywhere in each circuit. In this embodiment, the electric water pump 51 is arranged upstream of the sub-radiator 52. The electric water pump 61 is arranged on the downstream side of the radiator 43. The sub radiator 52 is disposed on the front side of the vehicle with respect to the radiator 43, and is disposed on the front side of the radiator 43, thereby enhancing the cooling effect by the vehicle speed wind.

  Thus, in the vehicle cooling device 30 of the present invention, the electric water pump 61 is interposed between the EGR core 46b of the radiator 43 and the water-cooled EGR coolers 22a, 22b, and the EGR core 46b, the water-cooled EGR. The first EGR cooling circuit 60 including the coolers 22a and 22b and the electric water pump 61 is configured by a circuit independent of the main cooling circuit 40 having the engine core 46a.

The vehicle cooling device 30 supplies the cooling water W1 to the engine body 15 by forming two of the engine core 46a and the EGR core 46b by the partition plates 49a and 49b in the radiator 43, and the water-cooled EGR In this configuration, the cooling water W3 having a temperature range different from that of the cooling water W1 is supplied to the coolers 22a and 22b. The temperature of the cooling water W3 after being supplied to the water-cooled EGR coolers 22a and 22b, that is, the temperature of the cooling water W3 before passing through the radiator 43 is the amount of EGR gas G2, the load of the engine 10, and an unshown post-processing device. Depending on the presence or absence of regeneration, the temperature of the cooling water W1 may become higher. The temperature of each cooling water cooled by the radiator 43 and the sub radiator 52 is, for example, a temperature T1 of the cooling water W1 of 60 degrees or more and 90 degrees or less, a temperature T2 of the cooling water W2 of 40 degrees or more and 60 degrees or less, and The temperature T3 of the cooling water W3 is 40 degrees or more and 90 degrees or less.

  The operation of the vehicle cooling device 30 will be described. In the main cooling circuit 40 of the vehicular cooling device 30, when the engine 10 is started, the mechanical water pump 41 is driven by the rotation of the crankshaft 18, and the circulation of the cooling water W1 is started. When the temperature of the cooling water W1 on the outlet side of the engine 10 is less than the warm-up temperature Ta set to, for example, 60 degrees or more and 80 degrees or less immediately after the engine 10 is started, the thermostat 42 Then, the cooling water W1 is warmed up via the bypass passage 45. On the other hand, when the temperature of the cooling water W1 on the outlet side of the engine 10 is equal to or higher than the warm-up temperature Ta, the thermostat 42 is opened to pass the cooling water W1 through the cooling passage 44, and the cooling water W1 is passed through the engine core of the radiator 43. The engine body 15 is cooled by cooling at 46a.

  In the auxiliary cooling circuit 50, when the engine 10 is started, the electric water pump 51 is driven to start circulation of the cooling water W2. The sub-cooling circuit 50 is a water-cooled intercooler 13 to which the cooling water W2 cooled by the sub-radiator 52 is supplied, and the cooling water W2 is supercharged by the compressor 12a to exchange heat with the intake air A. The intake air A is cooled.

  In the first EGR cooling circuit 60, when the engine 10 is started, the electric water pump 61 is driven to start circulation of the cooling water W3. The first EGR cooling circuit 60 is a water-cooled EGR cooler 22a, 22b supplied with cooling water W3 cooled by the EGR core 46b of the radiator 43, and EGR taken in from the cooling water W3 and the EGR passages 21a, 21b. The EGR gas G2 is cooled by heat exchange with the gas G2.

  In this way, the first EGR cooling circuit 60 that supplies the cooling water W3 cooled by the EGR core 46b of the radiator 43 to the water-cooled EGR coolers 22a and 22b, the electric water pump 61, and the main cooling circuit 40 By using independent circuits, the first EGR cooling circuit 60 and the main cooling circuit 40 are prevented from affecting each other, and the cooling efficiency in each cooling circuit is improved, so that the engine body 15 and the EGR gas Both of G2 can be efficiently cooled.

  As described above, the cooling water W3 circulating through the first EGR cooling circuit 60 has a temperature of the cooling water W1 of the main cooling circuit 40 depending on the amount of the EGR gas G2, the load on the engine 10, and whether or not the post-processing device (not shown) is regenerated. Higher temperature. However, by making the first EGR cooling circuit 60 independent of the main cooling circuit 40, it is possible to avoid an increase in the thermal load of the main cooling circuit 40 due to the temperature of the cooling water W3. Further, in the main cooling circuit 40, the cooling water W1 is maintained at the warm-up temperature Ta or higher as the engine 10 is warmed up. However, since there is no such restriction in the first EGR cooling circuit 60, the EGR of the radiator 43 is not affected. Since the temperature of the cooling water W3 cooled by the engine core 46b can be made lower than the temperature of the cooling water W1 cooled by the engine core 46a, the water-cooled EGR coolers 22a and 22b can be efficiently cooled. .

In particular, the vehicular cooling device 30 is suitable for a large vehicle such as a truck equipped with an engine 10 having a large number of cylinders of six cylinders or more, and efficiently cools even when a large amount of EGR gas G2 is refluxed. Can do. In this embodiment, in order to optimize the intake pulsation effect and the exhaust pulsation effect, each of the intake passage 11 and the exhaust passage 17 is branched and provided with a plurality of manifolds. Therefore, the two EGR passages 21a and 21b They are arranged in parallel. Therefore, it is necessary to cool the water-cooled EGR coolers 22a and 22b interposed in the EGR passages 21a and 21b at a time. Therefore, by configuring the first EGR cooling circuit 60 as a circuit independent of the main cooling circuit 40, even if a plurality of water-cooled EGR coolers 22a and 22b are provided to recirculate a large amount of EGR gas G2, the EGR gas Since G2 can be effectively cooled, NOx contained in the exhaust gas G1 can be effectively reduced.

  Further, the cooling water W2 cooled by the sub-radiator 52 by the sub-cooling circuit 50 independent of the main cooling circuit 40 and the first EGR cooling circuit 60 is directly supplied to the water-cooled intercooler 13, so that the turbocharger 12 The intake air A supercharged by the compressor 12a can be effectively cooled. Thereby, without increasing the work of the compressor 12a, the amount of the intake air A can be increased, and the fuel efficiency can be improved while suppressing the deterioration of the exhaust gas performance.

  FIG. 3 illustrates a vehicle cooling device 30 according to the second embodiment of the present invention. The EGR system 20 of the second embodiment has a configuration in which a plurality of EGR passages 21a and 21b are arranged in parallel with the engine 10 including a plurality of intake manifolds 14a and 14b and a plurality of exhaust manifolds 16a and 16b. Instead, after the EGR gas G2 is taken into the EGR passage 21 from the exhaust passage 17 and cooled by each of the water-cooled EGR coolers 22a and 22b provided in the EGR passage 21, the intake passage is opened by opening the EGR valve 23. 11 is configured to be supplied.

  Each of the water-cooled EGR coolers 22a and 22b is arranged in series with the EGR passage 21, and the EGR gas G2 is first cooled after passing through the water-cooled EGR cooler 22a arranged on the upstream side of the EGR passage 21. The water-cooled EGR cooler 22b disposed downstream is further cooled. Thus, when each water-cooled EGR cooler 22a, 22b is arranged in series, the temperature zone of each cooling water of each water-cooled EGR cooler 22a, 22b is made different, and it is a back | latter stage rather than the water-cooled EGR cooler 22a of a front | former stage. It is desirable to lower the temperature zone of the water-cooled EGR cooler 22b.

  Therefore, the vehicular cooling device 30 of the second embodiment includes a water-cooled EGR cooler 22b on the downstream side of the EGR passage 21 and a water-cooled EGR cooler 22a on the upstream side in the order in which the cooling water W3 of the first EGR cooling circuit 60 flows. It is arranged in series.

  The vehicular cooling device 30 supplies the cooling water W3 to the upstream water-cooled EGR cooler 22a next to the downstream water-cooled EGR cooler 22b in the order opposite to the order in which the EGR gas G2 passes. By doing so, the cooling water W3 having a relatively high temperature is supplied to the upstream water-cooled EGR cooler 22a, and the cooling water W3 having a low water temperature is supplied by the downstream water-cooling EGR cooler 22b. Therefore, the upstream water-cooled EGR cooler 22a to which the relatively high water temperature cooling water W3 is supplied takes the rough heat of the high temperature EGR gas G2, and the downstream water cooling type to which the lower water temperature cooling water W3 is supplied. Cool to a lower temperature with the EGR cooler 22b. That is, the EGR gas G2 can be reliably cooled to a lower temperature by cooling in stages with the water-cooled EGR cooler 22a and the water-cooled EGR cooler 22b that are in different temperature zones. For example, the EGR gas G2 has a high temperature of 500 ° C. or higher when the load is high or when a post-processing apparatus (not shown) is regenerated, but can be cooled to less than 100 ° C. by cooling in multiple stages.

  Two water-cooled EGR coolers as in the second embodiment may be interposed in each of the EGR passages 21a and 21b of the first embodiment.

  4 and 5 illustrate a vehicle cooling device 30 according to the third embodiment of the present invention. In addition to the configuration of the second embodiment, the vehicular cooling device 30 of the third embodiment branches from the main cooling circuit 40 and circulates the cooling water W1 to the water-cooled EGR cooler 22a by the mechanical water pump 41. Two EGR cooling circuits 70 are provided. Then, the cooling water W1 or the cooling water W3 is supplied to the water-cooled EGR cooler 22a disposed on the upstream side of the EGR passage 21 by one of the first EGR cooling circuit 60 and the second EGR cooling circuit 70, and the other by EGR The cooling water W3 or the cooling water W1 is configured to be supplied to the water-cooled EGR cooler 22b disposed on the downstream side of the passage 21.

  In FIG. 4, the cooling water W <b> 1 is supplied to the water-cooled EGR cooler 22 a disposed upstream of the EGR passage 21 by the second EGR cooling circuit 70, and is disposed downstream of the EGR passage 21 by the first EGR cooling circuit 60. The cooling water W3 is supplied to the water-cooled EGR cooler 22b.

  On the other hand, FIG. 5 shows that the supply destination of the cooling water W3 of the first EGR cooling circuit 60 and the supply destination of the cooling water W1 of the second EGR cooling circuit 70 are exchanged, and the first EGR cooling circuit 60 upstream of the EGR passage 21 The cooling water W3 is supplied to the water-cooled EGR cooler 22a disposed in the second position, and the cooling water W1 is supplied to the water-cooled EGR cooler 22b disposed downstream of the EGR passage 21 by the second EGR cooling circuit 70.

  In this manner, the EGR gas G2 is cooled stepwise, specifically, first by the water-cooled EGR cooler 22a disposed on the upstream side of the EGR passage 21, and then cooled by the water-cooled EGR cooler 22b disposed on the downstream side. By doing so, the EGR gas G2 can be reliably cooled to a lower temperature. Further, the water-cooled EGR cooler 22a arranged on the upstream side and the water-cooled EGR cooler 22b arranged on the downstream side are made into independent circuits, and the temperature zones thereof are made different so that the first EGR cooling circuit 60 and the main The cooling efficiency in each cooling circuit with the cooling circuit 40 can be further improved. Thereby, both the engine main body 15 and the EGR gas G2 can be efficiently cooled.

  For example, when the water temperature after heat exchange with the upstream water-cooled EGR cooler 22a is substantially equal to or lower than the water temperature after heat exchange with the engine body 15, as shown in FIG. The cooling water W1 is supplied to the upstream water-cooled EGR cooler 22a by the second EGR cooling circuit 70, and the cooling water W3 is supplied to the downstream water-cooled EGR cooler 22b by the first EGR cooling circuit 60. Is preferred. By comprising in this way, since the cooling water W3 which circulates through the 1st EGR cooling circuit 60 can be made into a lower water temperature, the cooling effect of EGR gas G2 can be improved.

  On the other hand, when the water temperature after the heat exchange with the upstream water-cooled EGR cooler 22a becomes higher than the water temperature after the heat exchange with the engine body 15, as shown in FIG. 5, the first EGR cooling circuit Preferably, the cooling water W3 is supplied to the upstream water-cooled EGR cooler 22a by 60, and the cooling water W1 is supplied to the downstream water-cooled EGR cooler 22b by the second EGR cooling circuit 70. With this configuration, since the circulation of the cooling water W3 that becomes high temperature becomes an independent circuit, it is ensured that the heat load of the main cooling circuit 40 is increased by the second EGR cooling circuit 70 branched from the main cooling circuit 40. Can be avoided.

  Two water-cooled EGR coolers as in the third embodiment may be interposed in each of the EGR passages 21a and 21b of the first embodiment.

10 Engine 11 Intake passage 17 Exhaust passages 21, 21a, 21b EGR passages 22a, 22b Water-cooled EGR coolers 23, 23a, 23b EGR valve 30 Vehicle cooling device 40 Main cooling circuit 43 Radiator 46 Radiator core 46a Engine core 46b For EGR Core 47 Upper tank 47a Engine inlet 47b EGR inlet 48 Lower tank 48a Engine outlet 48b EGR outlets 49a, 49b Partition plate 60 First EGR cooling circuit 61 Electric water pump

Claims (4)

A radiator for cooling engine cooling water is provided, and a partition plate is disposed in each of the upper tank and the lower tank of the radiator, and the radiator core of the radiator is divided into an engine core and an EGR core, and the upper tank The engine inlet and the EGR inlet are arranged in the lower tank, the engine outlet and the EGR outlet are arranged in the lower tank, and the cooling water cooled by the EGR core branches from the exhaust passage and joins the intake passage. In the vehicular cooling device configured to be supplied to the water-cooled EGR cooler interposed in the passage,
An electric water pump is interposed between the EGR core and the water-cooled EGR cooler,
The first EGR cooling circuit including the EGR core, the water-cooled EGR cooler, and the electric water pump is configured by a circuit independent of a main cooling circuit having the engine core. Cooling system.   The vehicle cooling device according to claim 1, wherein a plurality of the water-cooled EGR coolers are disposed in parallel in the EGR passage, and the plurality of water-cooled EGR coolers are connected in parallel in the first EGR cooling circuit.   A plurality of the water-cooled EGR coolers are interposed in series in the EGR passage, and in the first EGR cooling circuit, the water-cooled EGR cooler on the downstream side of the EGR passage in the order in which the cooling water flows in the first EGR cooling circuit. The vehicle cooling device according to claim 1, wherein the water-cooled EGR cooler on the upstream side is connected in series. A plurality of the water-cooled EGR coolers are interposed in the EGR passage,
A second EGR cooling circuit that circulates cooling water to the water-cooled EGR cooler by a mechanical water pump branched from the main cooling circuit and circulating the cooling water of the main cooling circuit;
Cooling water is supplied to the water-cooled EGR cooler disposed downstream of the EGR passage by one of the first EGR cooling circuit and the second EGR cooling circuit, and disposed upstream of the EGR passage by the other. The vehicle cooling device according to claim 1 or 2, wherein cooling water is supplied to the water-cooled EGR cooler.