Hybrid vehicle cooling system

Abstract

To inhibit occurrence of condensed water in a heat exchanger.SOLUTION: A hybrid vehicle 500 include a PCU 60 which supplies electric power to an electric motor. An internal combustion engine 10 including a supercharger 20 includes an intercooler 30 which conducts heat exchange between intake air and a coolant. The cooling device has a connection passage 262 in which the coolant flows from the PCU 60 to the intercooler 30. The connection passage 262 is disposed so as to be located adjacent to an outer wall of an oil pan of the internal combustion engine 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cooling device for a hybrid vehicle. [Background technology]

[0002] For example, Patent Document 1 discloses a hybrid vehicle equipped with an internal combustion engine with a supercharger and an electric motor as a driving source for traveling. This hybrid vehicle is equipped with an inverter as a power control unit that supplies power to the electric motor. This hybrid vehicle is also equipped with a heat exchanger that exchanges heat between gas and coolant. More specifically, it is equipped with an intercooler that cools intake air supercharged by the supercharger. It also has a coolant passage through which coolant flows from the power control unit to the heat exchanger. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-79614 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the electronic components of the power control unit have a small heat capacity and are prone to temperature rise even at low temperatures, so cooling water is supplied even at low temperatures. When coolant is supplied to the power control unit at low temperatures, low-temperature coolant is supplied to the heat exchanger, which may result in excessive cooling of the gas in the heat exchanger, resulting in condensation of water. [Means for solving the problem]

[0005] A cooling device for a hybrid vehicle that solves the above-mentioned problems is a cooling device applied to a hybrid vehicle equipped with an internal combustion engine and an electric motor as drive sources for running. The hybrid vehicle is equipped with a power control unit that supplies power to the electric motor. The internal combustion engine is equipped with a heat exchanger that exchanges heat between gas and coolant. The cooling device has a coolant passage through which coolant flows from the power control unit toward the heat exchanger. The coolant passage is disposed adjacent to an outer wall of the oil pan of the internal combustion engine.

[0006] With this configuration, the temperature of the cooling water flowing through the cooling water passage rises due to heat received from the oil pan. Therefore, the cooling water that has passed through the power control unit flows into the heat exchanger at an elevated temperature. This prevents the gas from being overcooled in the heat exchanger, thereby reducing the generation of condensation in the heat exchanger.

[0007] In the cooling device, the cooling water passage may be made of a metal material. With this configuration, the amount of temperature rise of the cooling water flowing through the cooling water passage is greater than when the cooling water passage is made of a material with a lower thermal conductivity than metal, such as resin or rubber, and therefore the generation of condensation water in the heat exchanger can be further suppressed.

[0008] In the cooling device, the cooling water passage may be arranged to pass below an outer wall of the oil pan. Furthermore, in the case where the internal combustion engine is equipped with a supercharger and an intercooler that cools intake air supercharged by the supercharger, the intercooler can be used as the heat exchanger.

[0009] In addition, if the internal combustion engine is equipped with an EGR passage that recirculates exhaust gas from the exhaust passage to the intake passage, and an EGR cooler that cools the exhaust gas passing through the EGR passage, the EGR cooler can be used as the heat exchanger. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating a schematic configuration of a cooling device for a hybrid vehicle according to an embodiment; [Figure 2] 4 is a diagram showing the positional relationship between an oil pan and a cooling water passage in the embodiment; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment will be described with reference to the drawings. <Vehicle configuration> Vehicle 500 is a hybrid vehicle equipped with an internal combustion engine and an electric motor as drive sources for traveling.

[0012] As shown in FIG. 1, a vehicle 500 is equipped with an internal combustion engine 10 . The internal combustion engine 10 includes a supercharger 20 and a water-cooled intercooler 30 that cools the intake air, which is gas supercharged by the supercharger 20, with cooling water.

[0013] The crankshaft of the internal combustion engine 10 is connected to a power split mechanism 53 provided in the transaxle 50. The transaxle 50 is disposed adjacent to the internal combustion engine 10. The first motor generator 51 and the second motor generator 52 are drivingly connected to the power split mechanism 53. Furthermore, the driving wheels of the vehicle 500 are connected to the power split mechanism 53 via a differential gear or the like (not shown).

[0014] The first motor generator 51 functions as a generator that generates electricity using engine output, and also functions as a starting starter (electric motor) that cranks the crankshaft when starting the internal combustion engine 10. The second motor generator 52 functions as an electric motor that generates driving force for the drive wheels, and also functions as a generator that generates electricity by regenerative braking when the vehicle 500 is decelerating.

[0015] The vehicle 500 includes a power control unit (hereinafter referred to as PCU) 60 that includes electronic components such as power transistors. The PCU 60 is a power supply device that receives power from a battery (not shown) and supplies power to the first motor generator 51 and the second motor generator 52. The PCU 60 includes a converter that boosts and outputs a DC voltage input from the battery, and an inverter that converts the DC voltage boosted by the converter into an AC voltage and outputs it to the first motor generator 51 and the second motor generator 52. Note that, although the PCU 60 in this embodiment is mounted on the transaxle 50 as an example, it may be disposed in another location.

[0016] <Vehicle cooling system> The vehicle 500 is equipped with a first cooling system 100 through which coolant circulates, primarily for the purpose of cooling the internal combustion engine 10. The vehicle 500 is also equipped with a second cooling system 200 through which coolant circulates, primarily for the purpose of cooling the turbocharger 20, the intercooler 30, and the PCU 60.

[0017] The first cooling system 100 includes a first radiator 120 . The first radiator 120 is a heat exchanger that cools the coolant that has become hot by circulating through a water jacket or the like provided inside the internal combustion engine 10.

[0018] The first radiator 120 is provided with a first fan 110 that cools the first radiator 120. The first fan 110 is, for example, an electric cooling fan driven by a motor.

[0019] The coolant is circulated between the first radiator 120 and the internal combustion engine 10 via a first coolant passage 130 that connects the first radiator 120 and the internal combustion engine 10. In addition, the first cooling system 100 also includes a water pump, a thermostat, a bypass passage that circulates the coolant bypassing the first radiator 120, a reserve tank, and the like, all of which are not shown.

[0020] The second cooling system 200 includes a second radiator 220 . The second radiator 220 is a heat exchanger that cools the intake air passing through the supercharger 20 and the intercooler 30, and the cooling water that has become hot by cooling the PCU 60.

[0021] The second radiator 220 is provided with a second fan 210 that cools the second radiator 220. The second fan 210 is, for example, an electric cooling fan driven by a motor.

[0022] The second cooling system 200 includes an outflow passage 240 , a first branch passage 250 , a second branch passage 260 , and an inflow passage 270 . The outflow passage 240 is a coolant passage connected to an out-port of the second radiator 220 through which the coolant cooled by the second radiator 220 flows out.

[0023] The first branch passage 250 is a coolant passage branched off from the outflow passage 240. A water jacket provided in the supercharger 20 is connected to the middle of the first branch passage 250. The second branch passage 260 is also a coolant passage branching off from the outflow passage 240. The PCU 60 and the intercooler 30 are connected midway through this second branch passage 260. More specifically, the second branch passage 260 has a connection passage 262 in which the PCU 60 and the intercooler 30 are connected in series in this order in the direction of the coolant flow. This connection passage 262 is a coolant passage through which the coolant flows from the PCU 60 toward the intercooler 30. The connection passage 262 is made of a metal material (e.g., aluminum, copper, iron, etc.).

[0024] The inflow passage 270 is a coolant passage where a first branch passage 250 and a second branch passage 260 branching from the outflow passage 240 converge. The inflow passage 270 is connected to the inlet of the second radiator 220 through which the coolant flows into the second radiator 220.

[0025] In addition, the second cooling system 200 is also provided with a water pump, a reserve tank, and the like, which are not shown. 2 shows the location of the connecting passage 262. In the following, the vertical direction will be referred to as downward.

[0026] As shown in Fig. 2, an oil pan 14 for storing lubricating oil is provided below the cylinder block 11 of the internal combustion engine 10. When the internal combustion engine 10 starts operating, the lubricating oil, whose temperature has risen due to heat received from various parts of the engine, returns to the oil pan 14. The connecting passage 262 is disposed adjacent to the outer wall of the oil pan 14. More specifically, the connecting passage 262 is disposed so as to pass below the outer wall of the oil pan 14. The distance L between the outer wall of the oil pan 14 and the connecting passage 262 is set to a distance that allows the temperature of the cooling water flowing through the connecting passage 262 to be increased to a degree that suppresses the generation of condensation in the intercooler 30. Note that it is desirable that the distance L be greater than "0" to avoid contact between the oil pan 14 and the connecting passage 262 due to engine vibrations, etc. However, for example, the distance L may be set to "0", that is, the connecting passage 262 may be disposed so that the oil pan 14 and the connecting passage 262 come into contact with each other.

[0027] <Action and effect> The operation and effects of this embodiment will be described. (1) The temperature of the cooling water flowing through the connecting passage 262 increases due to heat received from the oil pan 14. Therefore, the cooling water that has passed through the PCU 60 flows into the intercooler 30 with its temperature increased. This prevents the intake air from being overcooled in the intercooler 30, thereby preventing condensation in the intercooler 30.

[0028] (2) The connecting passage 262 is made of a metal material. Therefore, the temperature of the coolant flowing through the connecting passage 262 increases more than when the connecting passage 262 is made of a material with a lower thermal conductivity than a metal material, such as resin or rubber. Therefore, the generation of condensed water in the intercooler 30 can be further suppressed.

[0029] <Example of change> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0030] Although the connecting passage 262 is disposed so as to pass under the outer wall of the oil pan 14, the connecting passage 262 may be disposed so as to pass near the side surface of the outer wall of the oil pan 14. The connection passage 262 may be made of resin, rubber, etc. In this case, effects other than the above (2) can also be obtained.

[0031] In the above embodiment, the heat exchanger into which the coolant that has passed through the PCU 60 flows is the intercooler 30, but other heat exchangers may be used. For example, if the internal combustion engine 10 is equipped with an EGR passage that recirculates exhaust gas from the exhaust passage to the intake passage and an EGR cooler that cools the exhaust gas passing through this EGR passage, the EGR cooler may be used as the heat exchanger. In this case, it is possible to suppress the generation of condensed water in the EGR cooler.

[0032] Although the turbocharger 20 is disposed in the first branch passage 250, other devices may be disposed therein. Although the second cooling system 200 has the first branch passage 250, it does not have to have the first branch passage 250. In this case, the turbocharger 20 may be cooled by the cooling water flowing through the first cooling system 100, for example.

[0033] In the second branch passage 260, devices other than the PCU 60 and the intercooler 30 may be arranged. The number of motor generators provided in the vehicle 500 can be changed as appropriate as long as it is one or more.

[0034] The hybrid system of the vehicle is not limited to the system shown in FIG. 1, and may be any other system. [Explanation of symbols]

[0035] 10...Internal combustion engine 11...Cylinder block 14...Oil pan 20...Turbocharger 30...Intercooler 50...Transaxle 51...First motor generator 52...Second motor generator 53…Power splitting mechanism 60...Power control unit 100...1st cooling system 110...1st fan 120...First radiator 130...1st cooling water passage 200…Second cooling system 210...Second fan 220...Second radiator 240...Outflow passage 250...First branch passage 260...Second branch passage 262...Connecting passage 270...Inflow passage 500...vehicle

Claims

1. A cooling device applied to a hybrid vehicle equipped with an internal combustion engine and an electric motor as a driving source for traveling, the hybrid vehicle includes a power control unit that supplies power to the electric motor; the internal combustion engine includes a supercharger and an intercooler that cools intake air supercharged by the supercharger, the cooling device has a radiator that cools cooling water, an outflow passage through which the cooling water cooled by the radiator flows out, and a cooling water passage through which the cooling water flows from the power control unit toward the intercooler, the cooling water passage is disposed adjacent to an outer wall of an oil pan of the internal combustion engine, The cooling water flowing out from the radiator flows through the outflow passage, the power control unit, the cooling water passage, and the intercooler in this order. Hybrid vehicle cooling system.

2. The cooling water passage is made of a metal material. The cooling device for a hybrid vehicle according to claim 1.

3. The cooling water passage is disposed so as to pass under the outer wall of the oil pan. The cooling device for a hybrid vehicle according to claim 1 or 2.

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