JP6641865B2 - Vehicle cooling system - Google Patents

Description

  The present invention relates to a vehicle cooling device, and more particularly, to a vehicle cooling device that efficiently cools an engine, an intercooler, and a condenser for an air conditioning refrigerant.

  The cooling system for large vehicles such as trucks is equipped with a sub-radiator that is separate from the radiator that cools the cooling water for the engine, and supplies the cooling water cooled by the sub-radiator to the water-cooled intercooler to supercharge the water. Devices that increase the amount of intake air without increasing the work of the machine to improve exhaust gas performance and fuel efficiency have attracted attention.

  In addition, in a large vehicle, the load on the vehicle is larger than that of a passenger vehicle, and the weight of the vehicle is larger, so that the engine load is increased. As a result, the amount of heat released by an engine heat exchanger such as an intercooler or a radiator is increased. For this reason, an air-cooled condenser that cools the air-conditioning refrigerant used in the vehicle interior air-conditioning system cannot be disposed so as to overlap with the engine heat exchangers.

  In addition, in heavy-duty vehicles, since high-load running is frequently used, an engine axial force fan with a large air flow is used as a cooling fan for blowing air to the engine heat exchanger. Therefore, the cooling air for cooling the air-cooled condenser cannot be controlled in a situation where the air-cooled condenser needs to be cooled.

  Therefore, a water-cooled condenser that cools an air conditioning refrigerant by exchanging heat with cooling water has attracted attention.

  In connection with this, there has been proposed a device for supplying cooling water having a lower water temperature than a cooling water cooled by a radiator by a sub-radiator to a water-cooled intercooler or a water-cooled condenser (for example, see Patent Document 1).

  However, this device is configured to supply cooling water cooled by one sub-radiator to a water-cooled intercooler or a water-cooled condenser. As a result, the cooling water is first supplied to the water-cooled condenser with the lower temperature zone, and the cooling water heated by this water-cooled condenser is to be supplied to the next water-cooled intercooler. There is a problem that the cooler cannot be cooled efficiently.

JP 2005-186879 A

  An object of the present invention is to provide a vehicle cooling device capable of efficiently cooling each of an engine, an intercooler, and a condenser for an air conditioning refrigerant to improve fuel efficiency.

The vehicle cooling device of the present invention that achieves the above object cools both a radiator that cools engine cooling water, and a water-cooled intercooler that cools intake air supercharged by a supercharger and a refrigerant for air conditioning. A sub-radiator for cooling the cooling water of the water-cooled condenser, and a vehicular cooling device comprising: the water-cooled intercooler and the water-cooled condenser are arranged in parallel downstream of the sub-radiator with respect to the flow of cooling water, A first outlet serving as an outlet for cooling water supplied to the water-cooled intercooler and a second outlet serving as an outlet for cooling water supplied to the water-cooled condenser are formed in the sub-radiator, and is also the second outlet located downstream of the internal flow path of said sub-radiator, and a main cooling circuit having the radiator, the main cooling has the sub-radiator A sub-cooling circuit independent of the circuit, the main cooling circuit, the cooling water is one of a mechanical water pump, the engine, a cooling passage passing through the radiator and a bypass passage bypassing the radiator, and The sub-cooling circuit is configured to circulate the cooling water in order of the electric water pump, the sub-radiator, the water-cooled intercooler and the water-cooled condenser, and the electric water pump. And an auxiliary electric water pump for adjusting the flow rate of cooling water flowing through the water-cooled condenser is interposed between the sub-radiator and the water-cooled condenser .
In addition, the vehicle cooling device of the present invention that achieves the above object includes a radiator that cools engine cooling water, a water-cooled intercooler that cools intake air supercharged by a supercharger, and an air conditioning refrigerant. A sub-radiator for cooling the cooling water of a water-cooled condenser for cooling, wherein the radiator comprises a down-flow radiator in which cooling water flows from an upper tank toward a lower tank, and the sub-radiator Is composed of a side-flow type radiator in which cooling water flows from above to below while cooling water reciprocates from the upper tank to the lower tank, and the water-cooled intercooler, the water-cooled condenser, and Are arranged in parallel and serve as an outlet for cooling water supplied to the water-cooled intercooler One outlet and a second outlet serving as an outlet for the cooling water supplied to the water-cooled condenser are formed in the sub-radiator, and the second outlet is located downstream of the internal flow path of the sub-radiator from the first outlet. It is characterized by being arranged.

  According to the vehicle cooling device of the present invention, the water-cooled intercooler and the water-cooled condenser are arranged in parallel downstream of the sub-radiator, so that both the water-cooled intercooler and the water-cooled condenser are simultaneously cooled by the sub-radiator. Cooling water can be supplied. Further, by forming the first outlet and the second outlet disposed downstream of the internal flow from the first outlet in the sub-radiator, the water-cooled condenser has a cooling water supplied to the water-cooled intercooler. It is possible to supply cooling water having a lower water temperature. Thereby, each of the engine, the water-cooled intercooler, and the water-cooled condenser having different temperature zones can be more efficiently cooled.

  In particular, by directly supplying the cooling water cooled by the sub-radiator to the water-cooled intercooler, the intake air supercharged by the supercharger can be effectively cooled, so the work of the turbocharger is increased. Without increasing the amount of intake air, it is possible to improve fuel efficiency while suppressing deterioration of exhaust gas performance.

  In addition, by directly supplying the cooling water cooled by the sub-radiator to the water-cooled condenser, the air-conditioning refrigerant can be effectively cooled. Can be improved.

It is a lineblock diagram which illustrates the cooling device for vehicles of a first embodiment of the present invention. FIG. 2 is a perspective view illustrating a configuration of a radiator and a sub-radiator in FIG. 1. It is a lineblock diagram which illustrates the modification of the cooling device for vehicles of a first embodiment of the present invention. It is a lineblock diagram which illustrates the cooling device for vehicles of a second embodiment of the present invention. It is a lineblock diagram which illustrates the modification of the cooling device for vehicles of a second embodiment of the present invention. It is a lineblock diagram which illustrates the cooling device for vehicles of a third embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 illustrates a vehicle cooling device 30 according to a 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 condenser 23 mounted on the vehicle.

  In the engine 10, after the intake air A drawn into the intake passage 11 when the vehicle is running or the like is compressed by a compressor (supercharger) 12a of a turbocharger 12, the temperature becomes high, and the engine 10 is cooled by a water-cooled intercooler 13. It is supplied to the engine body 15 via the intake manifold 14. The intake air A supplied to the engine main body 15 is mixed with fuel in the cylinder and burns to generate thermal energy, and then becomes exhaust gas G1 and is exhausted from the exhaust manifold 16 to the exhaust passage 17 to be turbocharged. After driving the turbine 12b, the exhaust gas is purified by an exhaust gas purification device (not shown) and then released to the atmosphere.

In use, the air conditioning compressor 22 is driven by the electromagnetic clutch 21 with the driving force transmitted from the crankshaft 18 of the engine 10 via the power transmission mechanism 19 during use. The air-conditioning refrigerant R compressed by the air-conditioning compressor 22 is cooled by a water-cooled condenser 23 in a semi-liquid state at high temperature and high pressure, and further liquefaction proceeds. Water is removed. The liquefied air-conditioning refrigerant R is injected from the minute nozzle holes of the expansion valve 25 into the inside of the evaporator 26 and vaporized, and the evaporator 26 is cooled by removing heat from the evaporator 26 with the heat of vaporization at that time. This heat is deprived by the electric fan 27 to which electric power has been supplied, and the air passing through the cooled evaporator 26 is sent to the vehicle interior as cooling air.

  The vehicle cooling device 30 includes a cooling fan 31 connected to and driven by the crankshaft 18, a main cooling circuit 40, and a sub cooling circuit 50. The main cooling circuit 40 and the sub-cooling circuit 50 are independent circuits, and hereinafter, the cooling water flowing in each of them is distinguished from W1 and W2.

  In the main cooling circuit 40, the cooling water W1 is supplied to one of the mechanical water pump 41, the engine body 15, the thermostat 42, the cooling passage 44 in which the radiator 43 is provided, and the bypass passage 45 for bypassing the cooling passage 44. And circulates in the order of the mechanical water pump 41. Therefore, the main cooling circuit 40 is a circuit in which the cooling water W1 for cooling the engine body 15 circulates.

  In the sub cooling circuit 50, the cooling water W2 is a circuit independent of 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, the water-cooled condenser 23, and the electric water pump 51. are doing. Therefore, the sub-cooling circuit 50 is a circuit in which the cooling water W2 for cooling the water-cooled intercooler 13 and the water-cooled condenser 23 circulates.

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

  The thermostat 42 is arranged on the outlet side of the engine body 15 of the main cooling circuit 40. The thermostat 42 has a lifter (not shown) that expands and contracts with a thermal expansion body having a property of expanding with a rise in temperature and contracting with a decrease in temperature. The flow rate of the cooling water W1 flowing through the cooling passage 44 and the bypass passage 45 is adjusted by expanding and contracting the lifter according to the temperature. The thermostat 42 may be an electrothermal thermostat that forcibly expands and contracts the lift by electric heat.

  As in this embodiment, a thermostat 42 is disposed on the outlet side of the engine body 15 of the main cooling circuit 40, and the temperature of the cooling water W1 is controlled on the outlet side. Since it is possible to improve the pull-out property and to suppress the occurrence of cavitation, it is advantageous for improving the durability, and particularly suitable for large vehicles such as trucks.

  Note that, instead of the outlet control, an inlet control in which a thermostat 42 is arranged 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, the temperature control of the cooling water W1 is more advantageous than the outlet control.

  The radiator 43 is arranged 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 arranged behind the radiator 43. The radiator 43 cools the cooling water W1 passing through the inside using the vehicle speed wind and the cooling air from the subsequent cooling fan 31.

  The electric water pump 51 is a pump driven by electric power generated by an alternator (not shown). 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 with respect to the radiator 43 to enhance the cooling effect by the vehicle speed wind.

  In such a vehicle cooling device 30, in the sub-cooling circuit 50, the water-cooled intercooler 13 and the water-cooled condenser 23 are arranged in parallel downstream of the sub-radiator 52. A first outlet 53 serving as an outlet for the cooling water W3 supplied to the water-cooled intercooler 13 and a second outlet 54 serving as an outlet for the cooling water W4 supplied to the water-cooled condenser 23 are formed in the sub-radiator 52. The second outlet 54 is disposed downstream of the first outlet 53 downstream of the internal flow path 55 that is the flow path of the cooling water W2 flowing through the sub-radiator 52.

  That is, the vehicle cooling device 30 supplies the cooling water W3 to the water-cooled intercooler 13 by forming two of the first outlet 53 and the second outlet 54 in the sub-radiator 52, and supplies the cooling water W3 to the water-cooled condenser 23. The cooling water W3 is configured to simultaneously supply the cooling water W4 having a different temperature range from the cooling water W3. Further, since the cooling water W4 discharged from the second outlet 54 is cooled by the sub radiator 52 longer than the cooling water W3 discharged from the first outlet 53, the temperature T4 of the cooling water W4 is It becomes lower than the temperature T3.

  The cooling water W1 exchanges heat with the engine body 15, and by selecting whether the thermostat 42 passes through the cooling passage 44 or the bypass passage 45 depending on the temperature after the heat exchange, the mechanical water pump 41 The temperature T1 of the cooling water W1 supplied to the engine body 15 is adjusted. When the cooling water W2 exits the sub-radiator 52, it is branched into two, a cooling water W3 and a cooling water W4. The cooling water W3 exchanges heat with the intake air A passing through the water-cooled intercooler 13, and the cooling water W4 is cooled by a water-cooled water. After the heat exchange with the air-conditioning refrigerant R passing through the condenser 23, they join together. Accordingly, the temperature T1 of the cooling water W1 discharged from the mechanical water pump 41, the temperature T2 of the cooling water W2, the temperature T3 of the cooling water W3 after passing through the sub-radiator 52, and the cooling water W4 after passing through the sub-radiator 52 For example, the temperature T1 is 60 degrees or more and 90 degrees or less, the temperature T2 is 70 degrees or more and 90 degrees or less, the temperature T3 is 40 degrees or more and 60 degrees or less, and the temperature T4 is 50 degrees. It is as follows.

  The operation of the vehicle cooling device 30 will be described. In the main cooling circuit 40 of the vehicle cooling device 30, when the engine 10 starts, the mechanical water pump 41 is driven to start circulation of the cooling water W1. When the temperature of the cooling water W1 on the outlet side of the engine 10 immediately after the start of the engine 10 is lower than the warm-up temperature Ta set at, for example, 60 degrees or more and 80 degrees or less, the main cooling circuit 40 activates the thermostat 42. It is closed and 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 opens to allow the cooling water W1 to pass through the cooling passage 44 and cool the cooling water W1 by the radiator 43.

  In the sub-cooling circuit 50, when the engine 10 starts, the electric water pump 51 is driven to start circulation of the cooling water W2. The sub-cooling circuit 50 supplies the cooling water W3, which has been cooled from the first outlet 53, which is a position in the middle of the internal flow path 55 of the sub-radiator 52, to the water-cooled intercooler 13, and the water-cooled intercooler 13. In the cooler 13, the intake water A is cooled by the heat exchange between the intake water A and the supercharged cooling water W3 by the compressor 12a.

  In the sub-cooling circuit 50, the cooling water W4 cooled from the second outlet 54, which is the terminal position of the internal flow path 55 of the sub-radiator 52, to the water-cooled condenser 23, is supplied to the water-cooled condenser 23. At 23, the cooling water W4 and the air conditioning refrigerant R, which has been liquefied by the air conditioning compressor 22, perform heat exchange, thereby cooling the air conditioning refrigerant R.

  As described above, the water-cooled intercooler 13 and the water-cooled condenser 23 are arranged in parallel downstream of the sub-radiator 52 of the sub-cooling circuit 50, and the cooling water is simultaneously supplied to each of the water-cooled intercooler 13 and the water-cooled condenser 23. Since the supply is performed, the intake air A and the air conditioning refrigerant R can be simultaneously cooled by the cooling waters W3 and W4 cooled by the sub radiator 52. Further, since the sub-radiator 52 has the first outlet 53 and the second outlet 54 disposed downstream of the first outlet 53 in the internal flow path 55, the water-cooled condenser 23 has a water-cooled intercooler. The cooling water W4 having a lower water temperature than the cooling water W3 supplied to the cooling water 13 can be supplied. Thereby, cooling water having a water temperature suitable for each of the water-cooled intercooler 13 and the water-cooled condenser 23 having different temperature zones can be supplied, and cooling can be performed more efficiently.

  In particular, by directly supplying the cooling water W3 cooled by the sub-radiator 52 to the water-cooled intercooler 13, the intake air A supercharged by the compressor 12a of the turbocharger 12 can be effectively cooled. By increasing the amount of intake air A without increasing the work of the compressor 12a, it is possible to improve fuel efficiency while suppressing deterioration of exhaust gas performance.

  Further, by supplying the cooling water W4 further cooled by the sub-radiator 52 directly to the water-cooled condenser 23, the air-conditioning refrigerant R can be effectively cooled. It is possible to improve the fuel efficiency by preventing the above.

  Further, by using the water-cooled condenser 23 for cooling the air-conditioning refrigerant R with the cooling water W4 in the vehicle interior air-conditioning system 20, the electric fan which is indispensable in the air-cooled system can be eliminated. Can be suppressed, and the load on the alternator (not shown) can be reduced to further improve fuel efficiency.

  In addition, by configuring the vehicle cooling device 30 with the main cooling circuit 40 and the sub cooling circuit 50 independent of each other, the sub cooling circuit 50 is not affected by the cooling water W1 circulating through the main cooling circuit 40. That is, since the main cooling circuit 40 and the sub-cooling circuit 50 can have different temperature zones, the sub-cooling circuit 50 circulates the cooling water W2 having a lower water temperature than the main cooling circuit 40 without performing complicated control. be able to. This makes it possible to supply cooling water having a water temperature suitable for each of the engines having different temperature zones, the water-cooled intercooler 13, and the water-cooled condenser 23, and to cool efficiently.

  Next, a detailed configuration of the sub radiator 52 will be described with reference to FIG. FIG. 2 is a perspective view illustrating the radiator 43 and the sub radiator 52. In FIG. 2, white arrows indicate the respective cooling waters W1 to W4.

  The radiator 43 is a down-flow radiator in which an upper tank 47 and a lower tank 48 are arranged above and below a radiator core 46 composed of a number of flat tubes through which cooling water W1 flows and radiating fins. The radiator 43 is a radiator in which the inlet 47a of the cooling water W1 is arranged in the upper tank 47, and the cooling water outlet 48b is arranged in the lower tank 48, so that the number of the return of the flow path is reduced.

The sub-radiator 52 is a side-flow radiator in which an upper tank 57 and a lower tank 58 are arranged on the left and right of a radiator core 56 composed of a number of flat tubes through which cooling water W2 flows and radiating fins. The sub-radiator 52 is a radiator in which the number of folds of the internal flow path 55 is set to a plurality of times by dividing the inside of each of the upper tank 57 and the lower tank 58 with partition plates 59a to 59c. Is a radiator with a maximum of 4 passes. Then, an inlet 57a of the cooling water W2 is arranged in the upper tank 57, the first outlet 53 is arranged in one of the upper tank 57 and the lower tank 58, and the second outlet 54 is arranged in the other. The first outlet 53 of the cooling water W3 is disposed in the lower tank 58, and the second outlet 54 of the cooling water W4 is disposed in the upper tank 57.

  In other words, in the sub-radiator 52, the first outlet 53 is arranged where the number of turns of the internal flow path 55 is three, and the second outlet 54 is arranged where the number of turns of the internal flow path 55 is four. .

  The partition plates 59a to 59c have the upper tank 57 and the upper tank 57 so that the width of the internal passage 55 up to the third pass is equal and the width of the fourth pass is smaller than the width of the flow passage up to the third pass. It is arranged in the lower tank 58. By arranging the partition plates 59a to 59c in this manner, the flow rate of the cooling water W3 can be made larger than that of the cooling water W4. A flow rate can be supplied.

  In this embodiment, the partition plates 59a and 59c are disposed in the upper tank 57 and the partition plate 59b is disposed in the lower tank 58, so that the number of turns of the internal flow path 55 is four at the maximum. The number of folds may be two or more. Further, although the width of the flow path in the fourth pass is reduced, the width of each flow path may be equalized.

  In this way, the sub radiator 52 is divided into the upper tank 57 and the lower tank 58 by the partition plates 59a to 59c so that the number of turns of the internal flow path 55 is plural, and the sub radiator 52 is provided in one of the upper tank 57 and the lower tank 58. By arranging the one outlet 53 and the second outlet 54 on the other, the second outlet 54 can be arranged downstream of the internal flow path 55 from the first outlet 53. As a result, the cooling water W4 discharged from the second outlet 54 has a lower water temperature than the cooling water W3 having three turns by the four turns, and the cooling water W4 having the lower water temperature is supplied to the water-cooled condenser 23. Can be.

  In addition, the cooling water W3 having a large flow rate is supplied to the water-cooled intercooler 13 requiring a large flow rate, and the cooling water W4 having a small flow rate is supplied to the water-cooled condenser 23 having a relatively small flow rate. In addition, the water-cooled intercooler 13 can be prevented from being insufficiently cooled.

  Further, the radiator 43 is constituted by a one-pass down-flow radiator, and the sub-radiator 52 disposed in front of the radiator 43 is constituted by a side-flow radiator having a maximum of four passes. The configuration is such that the temperature decreases from the bottom to the bottom, so that the temperature below the radiator 43 can be prevented from rising due to the influence of the sub-radiator 52.

  FIG. 3 shows a modification of the vehicle cooling device 30 of the first embodiment of the present invention. In the modification of the first embodiment, an auxiliary electric water pump 60 for adjusting the flow rate of the cooling water W4 flowing through the water-cooled condenser 23 is interposed between the sub-radiator 52 of the sub-cooling circuit 50 and the water-cooled condenser 23. Is done.

  By arranging the auxiliary electric water pump 60 in this manner, when it is necessary to cool the air conditioning refrigerant R, the auxiliary electric water pump 60 is driven to supply a necessary amount of cooling water W4. it can. On the other hand, when there is no need to cool the air conditioning refrigerant R, that is, when the vehicle interior air conditioner 20 is not activated, the auxiliary electric water pump 60 is stopped, so that the cooling water W4 is not supplied to the water-cooled condenser 23. Then, the amount can be sent to the water-cooled intercooler 13. Thus, the cooling water cooled by the sub radiator 52 can be efficiently cooled without wasting.

  FIG. 4 illustrates a vehicle cooling device 30 according to a second embodiment of the present invention. In the vehicle cooling device 30 of the second embodiment, in addition to the configuration of the first embodiment, a water-cooled EGR cooler 71 provided in an EGR passage 70 is provided with a water-cooled intercooler 13 and a water-cooled The cooling water W <b> 3 discharged from the first outlet 53 is arranged in parallel with the condenser 23, and is branched and supplied to the water-cooled EGR cooler 71.

  The engine 10 includes an EGR passage 70 that recirculates the EGR gas G2 from the exhaust passage 17 to the intake passage 11. A water-cooled EGR cooler 71 and an EGR valve 72 are provided in the EGR passage 70. The EGR gas G2 is configured to recirculate when opened.

  By branching and supplying the cooling water W3 to the water-cooled EGR cooler 71, the main cooling circuit 40 is circulated to the water-cooled EGR cooler 71 in addition to the water-cooled intercooler 13 and the water-cooled condenser 23. Since the cooling water W3 having a lower water temperature than the cooling water W1 can be supplied to effectively cool the EGR gas G2 passing through the water-cooled EGR cooler 71, NOx contained in the exhaust gas G1 can be further reduced. .

  When the number of cylinders of the engine 10 is large in a large vehicle, a plurality of EGR passages 70 for recirculating the EGR gas G2 are provided in separate cylinders, and a water-cooled EGR cooler 71 is provided in each of the plurality of EGR passages 70. May be interposed. When the number of cylinders of the engine 10 is large as described above, the amount of the EGR gas G2 that is cooled by the water-cooled EGR coolers 71 at once by the plurality of water-cooled EGR coolers 71 provided in the plurality of EGR passages 70, respectively. Is reduced, the EGR gas G2 can be cooled efficiently. Further, the EGR passage 70 may be a low-pressure type that branches off from the exhaust passage 17 downstream of the turbocharger 12 in addition to a high-pressure type that branches off from the exhaust passage 17 upstream of the turbocharger 12.

  FIG. 5 shows a modification of the vehicle cooling device 30 of the second embodiment. The engine 10 has a plurality of water-cooled EGR coolers 71 and 73 arranged in an EGR passage 70. Each of the water-cooled EGR coolers 71 and 73 is arranged in series with the EGR passage 70, and the EGR gas G2 is first cooled after passing through the water-cooled EGR cooler 71 arranged upstream of the EGR passage 70. Is further cooled by passing through a water-cooled EGR cooler 73 arranged on the downstream side. When the water-cooled EGR coolers 71 and 73 are arranged in series as described above, the temperature zones of the respective cooling waters of the water-cooled EGR coolers 71 and 73 are made different, and the water-cooled EGR coolers 71 and 73 are provided at a stage subsequent to the preceding water-cooled EGR cooler 71. It is desirable to lower the temperature zone of the water-cooled EGR cooler 73.

  Therefore, in the vehicle cooling device 30, the cooling water W1 of the main cooling circuit 40 is supplied to the water-cooled EGR cooler 71 arranged on the upstream side of the EGR passage 70, while being cooled by the sub radiator 52 of the sub cooling circuit 50. The cooled cooling water W3 is supplied to a water-cooled EGR cooler 73 disposed downstream of the EGR passage 70.

  In the vehicle cooling device 30, the upstream water-cooled EGR cooler 71 is supplied with a relatively high-temperature cooling water W1, and the downstream water-cooled EGR cooler 73 is supplied with a low-water-temperature cooling water W3. . Accordingly, the upstream water-cooled EGR cooler 71 to which the high-temperature cooling water W1 is supplied removes the coarse heat of the high-temperature EGR gas G2, and then the downstream-side water-cooling EGR cooler W3 to which the lower-temperature cooling water W3 is supplied. The cooling is performed by the EGR cooler 73 to a lower temperature. In other words, the EGR gas G2 is cooled to a lower temperature by cooling stepwise by the water-cooled EGR cooler 71 and the water-cooled EGR cooler 73 having different temperature zones.

As described above, the EGR gas G2 is cooled stepwise, specifically, first by the water-cooled EGR cooler 71 arranged on the upstream side of the EGR passage 70, and then cooled by the water-cooled EGR cooler 73 arranged 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 71 disposed on the upstream side and the water-cooled EGR cooler 73 disposed on the downstream side are formed as independent circuits, and the temperature zones of the cooling water W1 and W3 are made different, so that the main cooling is performed. The cooling efficiency in each of the cooling circuits of the circuit 40 and the sub-cooling circuit 50 can be further improved. Thereby, all of the engine body 15, the intake air A, the air conditioning refrigerant R, and the EGR gas G2 can be efficiently cooled.

  In addition, since the EGR gas G2 after heat exchange in the upstream water-cooled EGR cooler 71 is cooled by the cooling water W3 circulating in the sub-cooling circuit 50 in the downstream water-cooled EGR cooler 73, the downstream side is cooled. Since the temperature of the cooling water W3 after the heat exchange in the water-cooled EGR cooler 73 can be lowered, the temperature of the cooling water W2 circulating in the sub-cooling circuit 50 can be lowered. Accordingly, even if the water-cooled EGR cooler 73 is cooled by the sub-cooling circuit 50, the cooling water W3 and the cooling water W4 each having a low water temperature suitable for the water-cooled intercooler 13 and the water-cooled condenser 23 are supplied. Thus, the respective cooling effects can be improved.

  In this embodiment, a configuration in which the cooling water W1 circulating in the main cooling circuit 40 is supplied to the water-cooled EGR cooler 71 on the upstream side of the EGR passage 70 has been described as an example. The cooling water circulating through the cooling circuit may be supplied.

  FIG. 6 illustrates a vehicle cooling device 30 according to a third embodiment of the present invention. The vehicle cooling device 30 of the third embodiment is configured such that the main cooling circuit 40 and the sub cooling circuit 50 are not independent from each other, and the sub cooling circuit 50 branches off from the main cooling circuit 40.

  In this embodiment, two outlets of the mechanical water pump 41 are formed. In the sub cooling circuit 50, the cooling water W2 is configured to circulate in the order of the mechanical water pump 41, the sub radiator 52, the water-cooled intercooler 13, the water-cooled condenser 23, and the mechanical water pump 41. .

  The sub-cooling circuit 50 preferably branches off from one outlet of the mechanical water pump 41 and merges downstream of the thermostat 42, and merges downstream of the radiator 43 of the cooling passage 44 or downstream of the bypass passage 45. Is more preferred. When the cooling water W2 of the sub cooling circuit 50 joins the cooling water W1 upstream of the thermostat 42, when the temperature T2 of the cooling water W2 is higher than the warm-up temperature Ta, the temperature T1 of the cooling water W1 becomes the warm-up temperature Ta. Even when the temperature has not reached, the thermostat 42 may open and the cooling water W1 may be cooled by the radiator 43. When the temperature T2 is lower than the warm-up temperature Ta, the thermostat 42 may be closed and the cooling water W1 may not be cooled by the radiator 43 even when the temperature T1 of the cooling water W1 is equal to or higher than the warm-up temperature Ta. Therefore, by making the sub-cooling circuit 50 join the main cooling circuit 40 downstream of the thermostat 42, the influence on the temperature adjustment of the main cooling circuit 40 can be suppressed.

  As can be seen from this embodiment, the present invention can also be applied to the sub cooling circuit 50 that branches off from the main cooling circuit 40 and joins the main cooling circuit 40. Note that the third embodiment can also be configured to supply the cooling water W3 to the water-cooled EGR cooler as in the second embodiment.

DESCRIPTION OF SYMBOLS 10 Engine 12 Turbocharger 12a Compressor 13 Water-cooled intercooler 20 Cabin air conditioner 23 Water-cooled condenser 30 Vehicle cooling device 40 Main cooling circuit 41 Mechanical water pump 43 Radiator 50 Sub-cooling circuit 51 Electric water pump 52 Sub-radiator 53 One outlet 54 Second outlet 55 Internal flow path A Intake R Air conditioning refrigerant W1 to W4 Cooling water

Claims (7)

A radiator that cools the cooling water of the engine, and a sub-radiator that cools the cooling water of a water-cooled condenser that cools both the water-cooled intercooler that cools the intake air supercharged by the supercharger and the air-conditioning refrigerant. Vehicle cooling system,
The water-cooled intercooler and the water-cooled condenser are arranged in parallel downstream of the sub radiator with respect to the flow of cooling water,
A first outlet serving as an outlet of cooling water supplied to the water-cooled intercooler and a second outlet serving as an outlet of cooling water supplied to the water-cooled condenser are formed in the sub-radiator,
The second outlet is disposed downstream of the internal flow path of the sub-radiator than the first outlet ,
A main cooling circuit having the radiator, and a sub cooling circuit having the sub radiator and being independent of the main cooling circuit,
The main cooling circuit causes the cooling water to circulate in the order of a mechanical water pump, the engine, one of a cooling passage passing through the radiator and a bypass passage bypassing the radiator, and the mechanical water pump. Is composed of
The sub-cooling circuit is configured such that the cooling water circulates in the order of the electric water pump, the sub radiator, the water-cooled intercooler and the water-cooled condenser, and the electric water pump,
A vehicle cooling device , comprising an auxiliary electric water pump for adjusting a flow rate of cooling water flowing through the water-cooled condenser, between the sub-radiator and the water-cooled condenser . A radiator that cools the cooling water of the engine, and a sub-radiator that cools the cooling water of a water-cooled condenser that cools both the water-cooled intercooler that cools the intake air supercharged by the supercharger and the air-conditioning refrigerant. Vehicle cooling system,
The radiator is constituted by a down-flow radiator in which cooling water flows from the upper tank toward the lower tank, and the sub-radiator is configured such that the cooling water flows from an upper flow path to a lower flow path from an upper tank to a lower tank. It is composed of a side-flow radiator flowing toward
The water-cooled intercooler and the water-cooled condenser are arranged in parallel downstream of the sub-radiator with respect to the flow of cooling water,
A first outlet serving as an outlet of cooling water supplied to the water-cooled intercooler and a second outlet serving as an outlet of cooling water supplied to the water-cooled condenser are formed in the sub-radiator,
A cooling device for a vehicle, wherein the second outlet is disposed downstream of the first outlet in an internal flow path of the sub-radiator. A main cooling circuit having the radiator, and a sub cooling circuit having the sub radiator and being independent of the main cooling circuit,
The main cooling circuit causes the cooling water to circulate in the order of a mechanical water pump, the engine, one of a cooling passage passing through the radiator and a bypass passage bypassing the radiator, and the mechanical water pump. Is composed of
3. The sub cooling circuit according to claim 2 , wherein the cooling water is configured to circulate cooling water in order of the electric water pump, the sub radiator, the water-cooled intercooler and the water-cooled condenser, and the electric water pump. Vehicle cooling system.   4. The vehicle cooling device according to claim 3, wherein an auxiliary electric water pump that adjusts a flow rate of cooling water flowing through the water-cooled condenser is interposed between the sub-radiator and the water-cooled condenser. 5. A main cooling circuit having the radiator, and a sub cooling circuit branched from the main cooling circuit having the sub radiator,
In the main cooling circuit, the cooling water circulates in the order of a mechanical water pump, the engine, one of a cooling passage passing through the radiator, and a bypass passage bypassing the cooling passage, and the mechanical water pump. Is configured as
The sub cooling circuit, the cooling water, the mechanical water pump, the sub-radiator, the water-cooled intercooler and said water cooled condenser, and claims that is configured to circulate in the order of the mechanical water pump 2 4. The vehicle cooling device according to claim 1. Equipped with a water-cooled EGR cooler for cooling EGR gas,
The water-cooled intercooler, the water-cooled EGR cooler, and the water-cooled condenser are arranged in parallel downstream of the sub-radiator with respect to the flow of cooling water,
The vehicle cooling device according to any one of claims 1 to 5, wherein cooling water discharged from the first outlet is supplied to the water-cooled EGR cooler. A partition plate is disposed inside each of the upper tank and the lower tank of the sub-radiator, the number of turns of the internal flow path is plural, and the first outlet is disposed on one of the upper tank and the lower tank, The vehicle cooling device according to any one of claims 1 to 6 , wherein the second outlet is disposed on the other side.