JP5983453B2 - Intake air cooling system - Google Patents

Description

  The present invention relates to an intake air cooling device that cools intake air supplied to a combustion chamber of an internal combustion engine.

  In recent years, the engine displacement tends to be reduced (downsizing) in order to reduce fuel consumption. And it is becoming mainstream to compensate for the decrease in engine output due to downsizing with a supercharger. The supercharger is a device that rotates a turbine by exhaust energy (exhaust flow velocity energy and heat energy) of an engine and drives a compressor by the rotation of the turbine to supercharge intake air.

  In order to reduce fuel consumption, an EGR (Exhaust Gas Recirculation) device called LPL (Low Pressure Loop) is also used. The LPL-EGR is a device that extracts a part of exhaust gas from an exhaust pipe downstream of a turbocharger turbine and recirculates it to an intake pipe upstream of a compressor.

  As described above, in the vehicle in which the supercharged downsizing + LPL-EGR is combined, it is necessary to cool the intake air and the EGR, and therefore, cooling is performed using an intercooler (I / C) and an EGR cooler, respectively. In particular, I / C includes an air cooling type and a water cooling type. In the water cooling type, there is a system having a cooling circuit independent of the engine cooling circuit.

  The problem of LPL-EGR + I / C is how to treat or suppress the condensed water generated in the I / C section. There is no problem if the condensed water is constantly sucked into the engine, but once it accumulates somewhere in the intake system and if it is sucked into the engine at a certain time, the engine may break down. Therefore, in the prior art described in Patent Document 1, a water reservoir mechanism is provided in the intake passage. The water storage mechanism keeps the condensed water in one place and suppresses the condensed water from being sucked into the engine.

French Patent Application Publication No. 2922962

  In the prior art described in Patent Document 1 described above, a space for providing a water storage mechanism is required. Therefore, there is a problem that the intake path is enlarged or the I / C is increased by the water storage mechanism.

  Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to provide an intake air cooling device that can be downsized while suppressing a large amount of condensed water from being sucked into a combustion chamber at a time. And

  The present invention employs the following technical means in order to achieve the aforementioned object.

In the present invention, the intake duct (15) through which the intake air supplied to the combustion chamber (11b) of the internal combustion engine (11) flows, and the first cooling section (33) that is provided in the intake duct and cools the intake air that passes through the intake duct. ), A second cooling part (34) that is provided downstream of the first cooling part of the intake duct and cools the intake air that has passed through the first cooling part, and the cooling capacity of the first cooling part and the second cooling part and controlling the control means (18), wherein the second cooling unit is configured to positioned above the first cooling unit is located above the intake port of an internal combustion engine (11a), the control means Is an intake air cooling device that controls the cooling capacity of the first cooling portion and the second cooling portion so that the condensed water generated in the second cooling portion steadily reaches the combustion chamber together with the intake air.

  According to the present invention, the second cooling unit is positioned above the first cooling unit and is positioned above the intake port of the internal combustion engine. Therefore, since the condensed water generated in the second cooling unit steadily reaches the combustion chamber through the intake port due to gravity with the intake air, it is possible to suppress a large amount of condensed water from being sent to the combustion chamber at one time. Therefore, it is possible to suppress the internal combustion engine from being damaged by the condensed water generated in the second cooling unit. Further, the condensed water generated in the first cooling unit reaches the combustion chamber after passing through the second cooling unit located above the first cooling unit. Therefore, the condensed water generated in the first cooling unit becomes a resistance due to gravity and gradually flows to the second cooling unit. In addition, since the second cooling unit itself becomes a resistance to the flow of condensed water from the first cooling unit, it is possible to suppress a large amount of condensed water from the first cooling unit from flowing into the combustion chamber at a time. Further, the intake air cooling device of the present invention does not require a portion for retaining condensed water, and thus can be miniaturized. Therefore, the intake air cooling device of the present invention can be reduced in size while suppressing a large amount of condensed water from being sucked into the combustion chamber at a time.

  In addition, the code | symbol in the bracket | parenthesis of each above-mentioned means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

1 is a diagram schematically illustrating an internal combustion engine system 10 according to a first embodiment. It is the figure which showed a part of FIG. 1 with the perspective view. 3 is a flowchart showing control of the intake air cooling device 12. It is a figure showing simplified internal combustion engine system 10A of a 2nd embodiment.

  Hereinafter, a plurality of embodiments for carrying out the present invention will be described with reference to the drawings. In some embodiments, portions corresponding to the matters described in the preceding embodiments may be given the same reference numerals, or one letter may be added to the preceding reference numerals, and overlapping descriptions may be omitted. In addition, when a part of the configuration is described in each embodiment, the other parts of the configuration are the same as those of the embodiment described in advance. In addition to the combination of parts specifically described in each embodiment, the embodiments may be partially combined as long as the combination does not hinder the combination.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. The internal combustion engine system 10 includes an internal combustion engine 11, an intake air cooling device 12, a turbocharger 13, and an exhaust gas recirculation device 14. The internal combustion engine 11 is a traveling power source for a road traveling vehicle, for example. The internal combustion engine 11 can be provided by a self-ignition type diesel engine or a spark ignition type gasoline engine. The internal combustion engine system 10 includes an intake system and an exhaust system for the internal combustion engine 11. The intake system includes an intake duct 15 through which intake air taken in by the internal combustion engine 11 flows. The exhaust system includes an exhaust duct 16 through which exhaust gas discharged from the internal combustion engine 11 flows.

  The turbocharger 13 is provided between the exhaust system and the intake system. The turbocharger 13 provides a supercharger that recovers the energy of the exhaust gas flowing in the exhaust duct 16 and compresses the intake air. The turbocharger 13 includes a turbine 21 provided in the exhaust duct 16 and a compressor 22 provided in the intake duct 15. The turbine 21 converts the exhaust energy into rotation. The rotation of the turbine 21 is transmitted to the compressor 22, and the compressor 22 functions. The compressor 22 pressurizes the intake air.

  An exhaust gas recirculation device (EGR device) 14 is provided between the exhaust duct 16 and the intake duct 15. The EGR device 14 includes an EGR system. The EGR system includes an EGR duct 17 for returning a part of the exhaust gas to the intake duct 15. The EGR system includes an EGR cooler 23 that cools the EGR gas flowing through the EGR duct 17. The EGR cooler 23 is provided by a water-cooled heat exchanger that cools the EGR gas with the cooling water of the internal combustion engine 11. The EGR duct 17 has an EGR inlet (not shown) that opens to a low-pressure portion of the exhaust duct 16 and an EGR outlet 24 that opens to a pre-charging portion of the intake duct 15. The EGR system constitutes an LPL-EGR device.

  The intake system includes an intake air cooling device 12. The intake air cooling device 12 cools the intake air supplied to the combustion chamber of the internal combustion engine 11. The intake air cooling device 12 is also called an intercooler. The intake air cooling device 12 is provided between the compressor 22 and the internal combustion engine 11. The intake air cooling device 12 is a water-cooled type, and is supplied with cooling water cooled by the low-temperature radiator 31. The cooling water of the internal combustion engine 11 is cooled by the high temperature radiator 41.

  The high temperature radiator 41 constitutes an internal combustion engine cooling device 40. The internal combustion engine cooling device 40 includes a high water temperature circuit 42, a high temperature radiator 41, and a main water pump 43. The high temperature radiator 41 is provided in the high water temperature circuit 42. The high water temperature circuit 42 is connected to the internal combustion engine 11 and is a first circulation path through which cooling water for cooling the internal combustion engine 11 circulates. The high water temperature circuit 42 is provided with a high temperature radiator 41 and a main water pump 43. The main water pump 43 is a pump for circulating cooling water, and is a directly connected pump that is rotated by receiving the driving force of the internal combustion engine 11. The high temperature radiator 41 cools the cooling water circulating through the high water temperature circuit 42 by heat exchange with the outside air by the main water pump 43.

  The internal combustion engine system 10 further includes a control device 18 (ECU: Electronic Control Unit). The control device 18 is an engine control device that controls the internal combustion engine system 10. The control device 18 inputs signals from a plurality of sensors. For example, the control device 18 inputs a plurality of signals indicating the operating state of the internal combustion engine 11 such as the rotational speed of the internal combustion engine 11 and the intake air amount G of the internal combustion engine 11. The intake air amount is detected by a flow sensor 19 provided in the intake duct 15. The control device 18 executes a control process by executing a preset control program. The control device 18 controls a plurality of actuators. That is, the control device 18 controls a plurality of actuators in response to signals from a plurality of sensors. The control device 18 controls, for example, the fuel supply device 20, the intake air cooling device 12, and the internal combustion engine cooling device 40 for the internal combustion engine 11.

  The control device 18 is provided by a microcomputer provided with a computer-readable storage medium. The storage medium stores a computer-readable program. The storage medium can be provided by a semiconductor memory or a magnetic disk. The program is executed by the control device 18 to cause the control device 18 to function. The means provided by the controller 18 can also be referred to as a functional block or module that achieves a predetermined function.

  Next, the intake air cooling device 12 will be further described. The intake air cooling device 12 includes a low water temperature circuit 30, a low temperature radiator 31, a sub water pump 32, a first cooling unit 33, a second cooling unit 34, and a three-way valve 35. The low water temperature circuit 30 is a second circulation path through which cooling water for cooling the combustion air (intake air) sucked into the engine circulates. The low water temperature circuit 30 is provided with a sub water pump 32, a low temperature radiator 31, a first cooling unit 33, a second cooling unit 34, and a three-way valve 35. The sub water pump 32 is a pump for circulating cooling water. The sub-water pump 32 is controlled by the control device 18 in an activated state and a stopped state.

  The low-temperature radiator 31 cools the cooling water circulating in the low water temperature circuit 30 by the sub water pump 32 by exchanging heat with the outside air. The first cooling unit 33 and the second cooling unit 34 cool the combustion air (intake air) by heat exchange with the cooling water circulating in the low water temperature circuit 30 by the sub water pump 32.

  The three-way valve 35 is a flow rate adjusting unit that controls the flow rate of the cooling water flowing through each of the first cooling unit 33 and the second cooling unit 34. The three-way valve 35 is provided at a branching portion 36 where a passage through which cooling water flows to the first cooling portion 33 and a passage through which cooling water flows to the second cooling portion 34 are branched. The state of the three-way valve 35 is controlled by the control device 18. When the sub-water pump 32 is operating and the three-way valve 35 opens the two passages, the cooling water flows through the first cooling unit 33 and the second cooling unit 34. When the sub water pump 32 is operating and the three-way valve 35 is open only on the first cooling unit 33 side, the cooling water flows only to the first cooling unit 33. When the sub water pump 32 is operating and the three-way valve 35 is open only on the second cooling unit 34 side, the cooling water flows only to the second cooling unit 34. In this way, the cooling capacity of the cooling units 33 and 34 can be controlled by the three-way valve 35.

  In the high water temperature circuit 42 and the low water temperature circuit 30, the objects to be cooled are different from each other, and therefore the temperature of the circulating cooling water is also different from each other. In the present embodiment, the cooling water that cools the internal combustion engine 11 is hotter than the cooling water that cools the intake air, so the cooling water that circulates in the high water temperature circuit 42 is hotter than the cooling water that circulates in the low water temperature circuit 30. is there.

  The first cooling unit 33 and the second cooling unit 34 are provided in the intake duct 15 as shown in FIGS. 1 and 2 and cool the intake air passing therethrough. The first cooling unit 33 is provided on the downstream side of the compressor 22. The second cooling unit 34 is provided on the downstream side of the first cooling unit 33. Therefore, the second cooling unit 34 cools the intake air that has passed through the first cooling unit 33. The second cooling unit 34 is located above the first cooling unit 33 and is located above the intake port 11 a of the internal combustion engine 11. The upper direction is the upper direction in the vertical direction (the direction of gravity). Moreover, the 1st cooling part 33 is located below the inlet port 11a. Therefore, as shown in FIG. 1, the intake duct 15 has a curved portion 15a for guiding the intake air upward. The 1st cooling part 33 is provided in the upstream of the curved part 15a, and the 2nd cooling part 34 is provided in the downstream of the curved part 15a. Moreover, the 1st cooling part 33 and the 2nd cooling part 34 are provided in the part from which the intake duct 15 extends in a horizontal direction together like this embodiment, for example.

  The first cooling unit 33 has higher cooling performance (reduction in intake air temperature) for cooling the intake air than the second cooling unit 34. Since the first cooling unit 33 and the second cooling unit 34 are water-cooled, the first cooling unit 33 having a higher cooling performance is larger. The second cooling unit 34 has a cooling performance of, for example, 1 to 2 kW, and the first cooling unit 33 has a cooling performance of, for example, 5 kW to 30 kW.

  Next, control of the intake air cooling device 12 will be described with reference to FIG. The process shown in FIG. 3 is repeatedly executed by the control device 18 in a short time.

  The flow is started, and in step S1, it is determined whether there is an intake air cooling request. If there is a cooling request, the process proceeds to step S2, and if there is no cooling request, the process proceeds to step S8. For the cooling request, the control device 18 determines whether or not the intake air needs to be cooled based on the rotational speed of the internal combustion engine 11 and the intake air amount. In step S8, since there is no cooling request, the operation of the sub water pump 32 (sub WP) is stopped and this flow is ended.

  In step S2, since there is a cooling request, control is performed so that the sub-water pump 32 operates, and the process proceeds to step S3. As a result, the cooling water circulates in the low water temperature circuit 30.

  In step S3, it is determined whether or not the cooling load is equal to or less than the first predetermined value G1, and if it is equal to or less than the first predetermined value G1, the process proceeds to step S4. Move on. The cooling load is, for example, an intake air amount. When the intake air amount is small (when it is equal to or smaller than the first predetermined value G1), the cooling load is small.

  In step S4, since the cooling load is equal to or less than the first predetermined value G1, the cooling capacity (first cooling capacity) of the first cooling unit 33 is limited, and this flow ends. This is because the cooling performance of the first cooling unit 33 is higher, so that the cooling can be sufficiently performed only by the second cooling unit 34 when the cooling load is small. Therefore, in step S4, the control device 18 controls the state of the three-way valve 35, operates the second cooling unit 34 with priority, and controls the cooling water to flow only through the second cooling unit 34.

  In step S5, it is determined whether or not the cooling load is equal to or smaller than a second predetermined value G2. If the cooling load is equal to or smaller than the second predetermined value G2, the process proceeds to step S6. Move on. The second predetermined value G2 is a value with a larger cooling load than the first predetermined value G1.

  In step S6, since the cooling load is equal to or less than the second predetermined value G2, the cooling capacity (second cooling capacity) of the second cooling unit 34 is limited, and this flow is terminated. This is because the cooling performance of the second cooling unit 34 is lower, so that the cooling can be sufficiently performed only by the first cooling unit 33 when the cooling load is intermediate. Accordingly, in step S <b> 5, the control device 18 controls the state of the three-way valve 35, operates the first cooling unit 33 with priority, and controls the cooling water to flow only through the first cooling unit 33.

  In step S7, since the cooling load is greater than the second predetermined value G2, the present flow is terminated without limiting the cooling capacity of the first cooling unit 33 and the second cooling unit 34. When the cooling load is high, it is necessary to operate both the first cooling unit 33 and the second cooling unit 34. Therefore, in step S <b> 7, the control device 18 controls the state of the three-way valve 35 so that the cooling water flows through both the first cooling unit 33 and the second cooling unit 34.

As described above, in the control shown in FIG. 3, the cooling units 33 and 34 that operate according to the cooling load are selected. The cooling units 33 and 34 to be selected will be described with reference to Table 1. Table 1 is a table | surface which shows the operation condition in the case of low load and high load of each cooling part 33,34.

The case of the low load shown in Table 1 is a case where the cooling load is equal to or less than the first predetermined value G1. In the case of a high load, the cooling load is larger than the second predetermined value G1. As shown in Table 1, in the case of a low load, at least the second cooling unit 34 is controlled to operate (in a state of ◯) as in step S4, and the first cooling unit 33 stops operating ( (X state), the ability may be reduced (Δ state). In the case of a high load, at least the first cooling unit 33 is controlled to operate as in step S7. The second cooling unit 34 may be operated by stopping the operation or reducing the capacity. When operating with reduced capacity, the control device 18 controls the discharge amount of the sub water pump 32.

  As described above, in the present embodiment, the condensed water 37 generated in the second cooling unit 34 reaches the combustion chamber 11b steadily together with the intake air, so the condensed water 37 generated in the second cooling unit 34 causes the internal combustion engine. 11 can be prevented from being damaged. Further, the condensed water 37 generated in the first cooling section 33 reaches the combustion chamber 11b after passing through the second cooling section 34 located above. Therefore, the condensed water generated in the first cooling unit 33 becomes a resistance due to gravity and gradually flows to the second cooling unit 34. Further, since the second cooling unit 34 itself becomes a resistance of the flow of the condensed water 37 from the first cooling unit 33, it is possible to suppress a large amount of condensed water from the first cooling unit 33 from flowing into the combustion chamber 11b at a time. Can do. In addition, in the intake air cooling device 12 of the present embodiment, a portion for holding the condensed water 37 is unnecessary, and thus the size can be reduced. Therefore, in the intake air cooling device 12 of the present invention, it is possible to reduce the size while suppressing a large amount of the condensed water 37 from being sucked into the combustion chamber 11b at a time.

  In the present embodiment, the first cooling unit 33 has higher cooling performance for cooling the intake air than the second cooling unit 34. Accordingly, the cooling unit to be used can be selected according to the cooling load. Moreover, since the 2nd cooling part 34 is located above the inlet port 11a, an installation space is small in many cases. Even in such a small installation space, the second cooling unit 34 can be arranged. If the cooling performance is insufficient with only the second cooling section 34, the intake air can be reliably cooled by using the first cooling section 33 with high cooling performance. Moreover, since the 1st cooling part 33 with high cooling performance should just be arrange | positioned somewhere in the intake duct 15, it is easy to ensure an installation space.

  Furthermore, in the present embodiment, a flow rate sensor 19 that detects the intake air amount as a load detection unit that detects the cooling load, and a control device (control unit) 18 that controls the cooling capacity of the first cooling unit 33 and the second cooling unit 34. It is comprised including. Then, when the cooling load detected by the flow sensor 19 is lower than the first predetermined value G1, the control device 18 operates the second cooling unit 34 with priority over the first cooling unit 33. Thus, when the intake air amount (intake amount) is less than the first predetermined value G1, the second cooling unit 34 is used. Therefore, the condensed water 37 is generated only in the second cooling unit 34, and the condensed water 37 generated in the second cooling unit 34 is constantly sucked into the intake port 11a even with a low intake amount. This is because the condensed water 37 easily flows into the intake port 11a due to gravity because the second cooling unit 34 is located above the intake port 11a even with a low intake amount. Therefore, even if the intake air amount is low, the condensed water 37 does not accumulate in the intake duct 15, so that a large amount of water does not flow into the internal combustion engine 11 at once.

  In the present embodiment, the control device 18 operates the first cooling unit 33 with priority over the second cooling unit 34 when the cooling load detected by the flow sensor 19 is higher than the second predetermined value G2. Let Accordingly, since the intake air amount is larger than the second predetermined value G2, the first cooling unit 33 having excellent cooling performance is used. Therefore, the condensed water 37 is generated in the first cooling unit 33, and the condensed water 37 generated in the first cooling unit 33 is regularly sucked into the intake port 11a because of the high intake amount. This is because, in the case of a high intake amount, the condensed water 37 is carried to the intake port 11a by the air flow even in the first cooling unit 33 positioned below the intake port 11a. Therefore, even when the intake air amount is high, the condensed water 37 is steadily carried to the intake port 11a, so that a large amount of water does not flow into the internal combustion engine 11 at once.

  Therefore, when the intake air amount is low, the condensed water 37 of the second cooling unit 34 located above the intake port 11a is carried to the intake port 11a by gravity and weak airflow, and when the intake air amount is high, the condensed water 37 is below the intake port 11a. Condensed water 37 of the first cooling unit 33 located is carried to the intake port 11a through the second cooling unit 34 against the gravity by a strong airflow. In any case, since the condensed water 37 does not stay in the intake duct 15, it is possible to prevent a large amount of the condensed water 37 from being conveyed to the intake port 11a at a time.

  Further, in the present embodiment, the second cooling unit 34 is provided in the low water temperature circuit 30 and cools the intake air by exchanging heat between the cooling water circulating in the low water temperature circuit 30 and the intake air. The low water temperature circuit 30 (second circulation path) is a circuit independent of the high water temperature circuit 42 (first circulation path) through which cooling water for cooling the internal combustion engine 11 circulates. Cooling water that is cooler than water circulates. Thus, since the low-temperature cooling water is used, the cooling performance of the intake air cooling device 12 can be enhanced.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. The present embodiment is characterized in that the configuration of the low water temperature circuit 30 is different and an on-off valve 50 is used instead of the three-way valve 35. The on-off valve 50 is a flow rate adjusting unit that controls the flow rate of the cooling water flowing through each of the first cooling unit 33 and the second cooling unit 34. The on-off valve 50 is provided in a passage through which cooling water flows to the first cooling unit 33. The open / close state of the on-off valve 50 is controlled by the control device 18. When the sub water pump 32 is operating and the on-off valve 50 is in the open state, the cooling water flows through the first cooling unit 33 and the second cooling unit 34. When the sub-water pump 32 is operating and the on-off valve 50 is closed, the cooling water flows only to the second cooling unit 34. In this way, the cooling capacity of the cooling units 33 and 34 can be controlled by the on-off valve 50. Even when such an on-off valve 50 is used, the same operations and effects as those of the first embodiment described above can be achieved.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  The structure of the said embodiment is an illustration to the last, Comprising: The scope of the present invention is not limited to the range of these description. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

  In the first embodiment described above, both the first cooling unit 33 and the second cooling unit 34 are provided in the low water temperature circuit 30, but the present invention is not limited to the configuration in which both are provided in the low water temperature circuit 30. The part 33 may be provided in the low water temperature circuit 30, and the second cooling part 34 may be provided in the high water temperature circuit 42, or vice versa.

  In the first embodiment described above, control is performed using two predetermined values G1 and G2, but one predetermined value may be used. In the first embodiment described above, the load detecting means is realized by the flow sensor 19, but is not limited to the flow sensor 19, and may be a sensor for measuring the temperature of intake air, and detects other cooling loads. Any means is possible. In the second embodiment described above, the on-off valve 50 is provided in the passage through which the cooling water flows in the first cooling unit 33, but may be provided in the passage through which the cooling water flows in the second cooling unit 34.

DESCRIPTION OF SYMBOLS 11 ... Internal combustion engine 11a ... Inlet port 11b ... Combustion chamber 12 ... Intake air cooling device 15 ... Intake duct 18 ... Control device (control means) 19 ... Flow rate sensor (load detection means)
20 ... Fuel supply device 30 ... Low water temperature circuit (second circulation path)
DESCRIPTION OF SYMBOLS 31 ... Low temperature radiator 32 ... Sub water pump 33 ... 1st cooling part 34 ... 2nd cooling part 35 ... Three-way valve (flow rate adjustment means) 37 ... Condensed water 41 ... High temperature radiator 42 ... High water temperature circuit (1st circuit)
43 ... Main water pump 50 ... Open / close valve (flow rate adjusting means)

Claims (10)

An intake duct (15) through which intake air supplied to the combustion chamber (11b) of the internal combustion engine (11) flows;
A first cooling section (33) provided in the intake duct for cooling the intake air passing through the intake duct;
A second cooling part (34) provided on the downstream side of the first cooling part of the intake duct for cooling the intake air that has passed through the first cooling part;
Control means (18) for controlling the cooling capacity of the first cooling part and the second cooling part ,
The second cooling part is located above the first cooling part and is located above the intake port (11a) of the internal combustion engine ,
The control means controls the cooling capacity of the first cooling unit and the second cooling unit so that the condensed water generated in the second cooling unit reaches the combustion chamber steadily together with the intake air. Intake cooling system. Load detecting means (19) for detecting the cooling load of the intake air;
In accordance with the cooling load detected by the load detection means, the control means includes the first cooling section and the first cooling section so that the condensed water generated in the second cooling section steadily reaches the combustion chamber together with intake air. The intake air cooling device according to claim 1, wherein the cooling capacity of the second cooling unit is controlled. Load detecting means (19 ) for detecting the cooling load of the intake air;
The control means operates the second cooling section with priority over the first cooling section when the cooling load detected by the load detection means is lower than a predetermined value. Item 2. The intake air cooling device according to Item 1 . Load detecting means (19 ) for detecting the cooling load of the intake air;
The control means, when the cooling load detected by the load detection means is higher than a predetermined value, operates the first cooling part with priority over the second cooling part. intake air cooling apparatus according to 1. The intake air cooling device according to any one of claims 1 to 4, wherein the first cooling unit has a higher cooling performance for cooling the intake air than the second cooling unit. The second circulation path is independent of the first circulation path (42) through which the cooling water for cooling the internal combustion engine circulates, and the cooling water having a temperature lower than that of the cooling water in the first circulation path circulates. Further comprising a second circuit (30),
The second cooling unit is provided in the second circulation path, and cools the intake air by exchanging heat between the cooling water circulating in the second circulation path and the intake air. The intake air cooling device according to any one of 1 to 5 . The first cooling part and the second cooling part are provided in the second circulation path, cool the intake air by exchanging heat between the cooling water circulating in the second circulation path and the intake air,
The intake air cooling device according to claim 6 , further comprising flow rate adjusting means (35, 50) for controlling a flow rate of the cooling water flowing through each of the first cooling unit and the second cooling unit. The flow rate adjusting means is a three-way valve (35) provided at a branch portion where a passage through which the cooling water flows to the first cooling portion and a passage through which the cooling water flows to the second cooling portion. The intake-air cooling apparatus according to claim 7 , wherein the intake-air cooling apparatus is characterized. The flow rate adjusting means is an on-off valve (50) provided in any one of a passage through which the cooling water flows in the first cooling section and a passage through which the cooling water flows in the second cooling section. The intake air cooling device according to claim 7 . The intake air cooling device according to any one of claims 1 to 9, wherein intake air supplied to the combustion chamber of the internal combustion engine of a vehicle flows through the intake duct.

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