JP2008223488A - Cooling system for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling system for a hybrid vehicle capable of suppressing deterioration of fuel economy. <P>SOLUTION: The cooling system for the hybrid vehicle is provided with a first exhaust heat recovery unit; and a first cooling water passage. The first exhaust heat recovery unit is arranged on an exhaust passage of an internal combustion engine. The first cooling water passage is a cooling water passage for circulating cooling water between the internal combustion engine and the first exhaust heat recovery unit. Further, the cooling system for the hybrid vehicle is provided with a second cooling water passage provided independently of the first cooling water passage. The second cooling water passage is a cooling water passage for circulating cooling water between the first exhaust heat recovery unit and a heater core. Thereby, since the time when the temperature of cooling water of the first cooling water passage becomes a predetermined temperature or lower can be delayed, the number of restarting of the internal combustion engine can be also reduced. Namely, deterioration of the fuel economy can be suppressed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cooling system for a hybrid vehicle that circulates cooling water between a heater core and an exhaust heat recovery device.

  2. Description of the Related Art Conventionally, there has been proposed an exhaust heat utilization type heating device that uses exhaust heat of an engine for a heater core. For example, Patent Document 1 and Patent Document 2 disclose a technique for heating conditioned air by recovering exhaust heat from an internal combustion engine with cooling water using an exhaust heat recovery device and then circulating the cooling water to a heater core. Are listed.

JP 2006-283711 A JP 2000-240510 A

  By the way, in the hybrid vehicle, when the cooling water is radiated in the heater core when the engine is stopped, the temperature of the cooling water is lowered. In the hybrid vehicle, when the temperature of the cooling water falls below a certain level, the engine restarts to increase the temperature of the cooling water. That is, even if the engine stops, the engine restarts whenever the temperature of the cooling water decreases. If this happens frequently, the fuel efficiency will deteriorate despite the fact that the vehicle is a hybrid vehicle. However, Patent Document 1 and Patent Document 2 do not particularly examine this point.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a hybrid vehicle cooling system that can suppress deterioration in fuel consumption.

  In one aspect of the present invention, a first exhaust heat recovery device disposed on an exhaust passage of an internal combustion engine, and a first coolant water circulated between the internal combustion engine and the first exhaust heat recovery device. A cooling system for a hybrid vehicle including one cooling water passage and a heater core is provided between the first exhaust heat recovery device and the heater core, which are provided independently of the first cooling water passage. And a second cooling water passage for circulating the cooling water, and an electric pump for circulating the cooling water in the second cooling water passage.

  The cooling system for the hybrid vehicle includes a first exhaust heat recovery unit, a first cooling water passage, and a heater core. The first exhaust heat recovery unit is disposed on an exhaust passage of the internal combustion engine. The first cooling water passage is a cooling water passage that circulates cooling water between the internal combustion engine and the first exhaust heat recovery device.

  The hybrid vehicle cooling system includes a second cooling water passage provided independently of the first cooling water passage, and an electric pump for circulating the cooling water in the second cooling water passage. It has. The second cooling water passage is a cooling water passage through which the first exhaust heat recovery unit, the heater core, and the cooling water circulate. The term “independently provided” as used herein means that the second cooling water passage is not connected to the first cooling water passage, that is, the cooling water in the first cooling water passage and the This means that the cooling water in the second cooling water passage does not cross each other. Thus, since the second cooling water passage is provided independently of the first cooling water passage, the cooling water in the first cooling water passage is only for warming up the internal combustion engine. The cooling water in the second cooling water passage is used only for heat dissipation in the heater core.

  Therefore, in the cooling system of the hybrid vehicle described above, the temperature of the cooling water in the first cooling water passage is reduced when the internal combustion engine is stopped, compared to a general cooling system. You can delay when: Here, the predetermined temperature is the temperature of the cooling water that can smoothly warm up the internal combustion engine. When the temperature of the cooling water becomes lower than the predetermined temperature, the internal combustion engine is restarted. It is necessary to let In the cooling system for the hybrid vehicle described above, since the number of restarts of the internal combustion engine can be reduced as compared with a general cooling system, deterioration of fuel consumption can be suppressed.

  Another aspect of the cooling system for the hybrid vehicle described above is a second exhaust heat recovery device that is disposed on the exhaust passage and has a catalyst that is warmed up by the exhaust gas in the exhaust passage. A third cooling water passage that is provided independently of the first cooling water passage and circulates the cooling water between the second exhaust heat recovery device and the heater core, and the cooling water for the heater core. A valve for switching a route to be circulated between the second cooling water passage and the third cooling water passage; and a switching control means for controlling switching of the valve; When the internal combustion engine is stopped, control is performed to switch the route through which the cooling water of the heater core flows to the third cooling water passage. Here, the switching means is, for example, an ECU (Electronic Control Unit). The time for which the catalyst retains the heat of reaction is longer than the time for which the exhaust heat of the exhaust gas retains. Therefore, when the internal combustion engine is stopped, the time when the temperature of the cooling water becomes equal to or lower than the predetermined temperature can be further delayed.

  In another aspect of the cooling system for the hybrid vehicle described above, the switching means may be configured such that when the temperature of the catalyst is lower than a predetermined temperature, a route through which the cooling water for the heater core is circulated is the second cooling water. Control to switch to the passage. Specifically, the predetermined temperature is the lowest temperature at which the purification function of the catalyst does not deteriorate. By doing in this way, degradation of the purification function due to a decrease in the catalyst temperature of the catalyst can be suppressed.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[Configuration of cooling system]
FIG. 1 is a diagram showing a schematic configuration of a cooling system 100 according to each embodiment of the present invention. In FIG. 1, solid arrows indicate the flow of cooling water, and broken arrows indicate input / output of signals. A solid line indicated by a bold line indicates a passage (cooling water passage) through which the cooling water flows.

  The cooling system 100 according to each embodiment cools the engine 1 using cooling water, collects exhaust heat by exchanging heat between the cooling water and the exhaust gas, and warms the engine 1. This system is used as a heat source for the machine and the heater core 9. In this case, the cooling water cools and warms up the engine 1 by passing through the cooling water passages 7a, 7b, and 7c. The exhaust heat recovery device 2 is provided on the cooling water passage 7a, the radiator 3 is provided on the cooling water passage 7b, and the electric pump 5 is provided on the cooling water passage 7c.

  The engine (internal combustion engine) 1 is a device that generates power by burning a mixture of supplied fuel and air. For example, the engine 1 is configured by a gasoline engine, a diesel engine, or the like. The engine 1 is mounted on a hybrid vehicle or the like.

  The exhaust heat recovery device 2 is provided on an exhaust passage (not shown) through which exhaust gas from the engine 1 passes. The exhaust heat recovery device 2 recovers exhaust heat by allowing cooling water to pass through and exchanging heat between the cooling water and the exhaust gas. This exhaust heat recovery device 2 functions as a first exhaust heat recovery device in the present invention.

  In the radiator 3, the cooling water passing through the inside thereof is cooled by outside air. In this case, cooling of the cooling water in the radiator 3 is promoted by the wind introduced by the rotation of the electric fan (not shown). The electric pump (hereinafter referred to as “electric WP”) 5 includes an electric motor, and circulates cooling water in the cooling water passages 7a, 7b, and 7c by driving the motor. Specifically, the electric WP 5 is supplied with electric power from a battery, and the rotational speed and the like are controlled by a control signal supplied from the ECU 50.

  The thermostat 4 is configured by a valve that opens and closes according to the coolant temperature. Basically, the thermostat 4 is opened when the temperature of the coolant becomes high. In this case, the cooling water passage 7 b and the cooling water passage 7 c are connected via the thermostat 4, and the cooling water passes through the radiator 3. Thereby, a cooling water is cooled and the overheating of the engine 1 is suppressed. In contrast, when the coolant temperature is relatively low, the thermostat 4 is closed. In this case, the cooling water does not pass through the radiator 3. Thereby, since the water temperature fall of a cooling water is suppressed, the overcool of the engine 1 is suppressed.

  In the cooling system 100 according to each embodiment, the cooling water passage 7d provided independently of the cooling water passages 7a, 7b, and 7c is provided. Here, “provided independently” means that the cooling water passage 7d is not connected to the cooling water passages 7a, 7b, 7c, that is, the cooling water and the cooling water passage 7a of the cooling water passage 7d. , 7b, 7c means that they do not cross each other.

  An exhaust heat recovery unit 2, a heater core 9, and an electric WP 8 are provided on the cooling system passage 7d. In other words, the exhaust heat recovery device 2 is provided on the two cooling water passages 7a and 7d. The cooling water passage 7 d is a closed cooling water passage for circulating the cooling water through the exhaust heat recovery device 2 and the heater core 9. Here, the cooling water passages 7a, 7b, and 7c function as the first cooling water passage in the present invention, and the cooling water passage 7d functions as the second cooling water passage in the present invention.

The heater core 9 is a device that warms the air in the vehicle interior with cooling water passing through the inside. In this case, the air warmed by the heater core 9 is blown into the vehicle interior by a blower called a blower (not shown).

  The electric WP 8 circulates the cooling water in the cooling water passage 7d by driving the motor. Similarly to the electric WP5, the electric WP8 is also supplied with electric power from the battery, and the rotational speed and the like are controlled by a control signal S8 supplied from the ECU 50.

  The ECU (Electronic Control Unit) 50 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown). The ECU 50 executes control of the electric WP 8 based on the in-vehicle warm-up request from the user.

[First Embodiment]
Next, an example of the cooling system 100a according to the first embodiment will be specifically described with reference to FIG. FIG. 2 is an enlarged view showing a part of a cooling system 100a in which the exhaust heat recovery device 2 and the heater core 9 are connected by a cooling water passage 7d. The thick arrow indicates the flow of exhaust gas, the solid line arrow indicates the flow of cooling water, and the broken line arrow indicates input / output of signals. Further, in FIG. 2, the cooling water passage 7a is not shown.

  The exhaust heat recovery device 2 is provided on an exhaust passage 10 through which exhaust gas from the engine 1 flows. Specifically, the exhaust heat recovery device 2 is installed on the exhaust passage 10 on the downstream side of the catalyst 11 that purifies the exhaust gas.

  The exhaust heat recovery device 2 has a cooling water passage 12 disposed so as to cover the outer wall surface of the exhaust passage 10. For example, the cooling water passage 12 has a shape surrounding the exhaust passage 10 in a cylindrical shape. In the cooling water passage 12, the cooling water flows from the cooling water passage 7d as indicated by an arrow B1, and the cooling water flows out to the cooling water passage 7d as indicated by an arrow B2.

  By adopting such a structure, the exhaust heat recovery device 2 transmits the exhaust heat of the exhaust gas to the cooling water in the cooling water passage 12 through the wall surface of the exhaust passage 10 and realizes heat exchange. To do.

  The exhaust heat recovery device 2 has a cooling water passage (not shown) for warming up the engine 1 independent of the cooling water passage 12. The cooling water passage for warming up the engine 1 is also disposed so as to cover the outer wall surface of the exhaust passage. The cooling water passage 7 a is connected to a cooling water passage for warming up the engine 1. The cooling water flowing in from the cooling water passage 7a exchanges heat with the exhaust heat of the exhaust gas when passing through the warming-up cooling water passage of the engine 1, and then flows out to the cooling water passage 7a.

  As can be seen from the above description, in the cooling system 100a according to the first embodiment, the cooling water passages 7a, 7b, 7c for circulating the cooling water between the engine 1 and the exhaust heat recovery device 2 are independent. A cooling water passage 7d that circulates cooling water between the exhaust heat recovery device 2 and the heater core 9, an electric WP8 that circulates the cooling water in the cooling water passage 7d, and an ECU 50 that controls the electric WP8. I have. In this way, the cooling water passage 7d for circulating the cooling water between the exhaust heat recovery device 2 and the heater core 9 is used as the cooling water passage 7a, 7b for circulating the cooling water between the engine 1 and the exhaust heat recovery device 2. , 7c are provided as follows.

  For example, when the engine 1, the heater core 9, and the exhaust heat recovery device 2 are connected by one cooling water passage, specifically, the cooling water passage 7 d is not provided in FIG. Consider a general cooling system in which the heater core 9 is provided on the water passage 7a. In this case, when there is a vehicle warm-up request from the user, the ECU 50 drives the electric WP 5 to circulate the cooling water in the cooling water passages 7a, 7b, 7c. As a result, the cooling water heated by exchanging heat with the exhaust heat recovery device 2 dissipates heat when passing through the heater core 9 and warms the interior of the vehicle. However, in a general cooling system, the cooling water passes not only through the heater core 9 but also through the engine 1. Therefore, the heat of the cooling water is not only radiated by the heater core 9 but also radiated by the engine 1. Will be.

  Here, when the engine 1 is stopped, the exhaust gas does not flow in the exhaust passage 10. Therefore, the amount of heat transferred from the exhaust heat recovery device 2 to the cooling water decreases with time. For this reason, the amount of heat radiated from the cooling water in the heater core 9 and the engine 1 becomes larger than the amount of heat absorbed in the cooling water in the exhaust heat recovery device 2 with the passage of time, so the temperature of the cooling water gradually decreases. To do.

  When the temperature of the cooling water in the cooling water passages 7a, 7b, 7c becomes a predetermined temperature (for example, 65 ° C.) or lower, it is necessary to heat the cooling water in order to smoothly warm up the engine 1. is there. Therefore, the ECU 50 restarts the engine 1 when it is determined that the temperature of the cooling water is equal to or lower than the predetermined temperature based on a control signal supplied from a cooling water temperature sensor (not shown). That is, since the ECU 50 restarts the engine every time the temperature of the cooling water falls below the predetermined temperature, the fuel efficiency deteriorates despite the fact that the ECU 50 is a hybrid vehicle.

  Therefore, in the cooling system 100a according to the first embodiment, as described above, the cooling water passage 7d for circulating the cooling water between the exhaust heat recovery device 2 and the heater core 9 is provided with the engine 1 and the exhaust heat. The cooling water passages 7a, 7b, and 7c that circulate the cooling water with the recovery unit 2 are provided independently. Thus, the cooling water in the cooling water passages 7a, 7b, 7c is used only for warming up the engine 1, and the cooling water in the cooling water passage 7d is used only for heat dissipation in the heater core 9. Become.

  That is, in the cooling system 100a according to the first embodiment, the cooling water in the cooling water passages 7a, 7b, and 7c is radiated by the heater core 9 when the engine 1 is stopped as compared with a general cooling system. However, since the heat is radiated only by the engine 1, the rate of decrease in the water temperature can be reduced. Thereby, in the cooling system 100a according to the first embodiment, the temperature of the cooling water in the cooling water passages 7a, 7b, and 7c is the predetermined temperature when the engine 1 is stopped, as compared with a general cooling system. Since the following time can be delayed, the number of engine restarts can also be reduced, that is, deterioration of fuel consumption can be suppressed.

  Further, in the cooling system 100a according to the first embodiment, unlike a general cooling system, cooling water passages 7a, 7b, 7c for circulating the cooling water between the engine 1 and the exhaust heat recovery device 2, Electric cooling WPs 5 and 8 are provided in the cooling water passage 7d for circulating the cooling water between the heater core 9 and the exhaust heat recovery unit 2, respectively. Therefore, the cooling water can be circulated at different flow rates in the cooling water passages 7a, 7b, 7c and the cooling water passage 7d. For example, when the warm-up of the engine 1 is completed and there is a vehicle warm-up request from the user, the general cooling system increases the flow rate of cooling water flowing through the heater core 9. As a result, the flow rate of the cooling water flowing into the engine 1 also increased, and the engine 1 might be overheated. However, in this case, in the cooling system 100a according to the first embodiment, the flow rate of the cooling water in the cooling water passages 7a, 7b, and 7c is decreased, and the flow rate of the cooling water in the cooling water passage 7d is increased. As a result, overheating of the engine 1 can be prevented.

[Second Embodiment]
Next, a cooling system 100b according to a second embodiment of the present invention will be specifically described with reference to FIGS. 3 and 4 are enlarged views showing a part of the cooling system 100b in which the exhaust heat recovery devices 2, 2a and the heater core 9 are connected by the cooling water passages 7d, 7e. The thick arrow indicates the flow of exhaust gas, the solid line arrow indicates the flow of cooling water, and the broken line arrow indicates input / output of signals. 3 and 4 also omit illustration of the cooling water passage 7a.

Unlike the cooling system 100a according to the first embodiment described above, the cooling system 100b according to the second embodiment has a cooling water passage 7e branched from the cooling water passage 7d, and the exhaust heat recovery device 2 In addition, an exhaust heat recovery device 2a is provided. The exhaust heat recovery device 2a is provided on the cooling water passage 7e. The cooling water passage 7e is also a cooling water passage provided independently of the cooling water passages 7a, 7b, and 7c passing through the engine 1, similarly to the cooling water passage 7d. The exhaust heat recovery device 2a functions as the second exhaust heat recovery device in the present invention, and the cooling water passage 7e.
However, it functions as the third coolant passage in the present invention.

  Similarly to the exhaust heat recovery unit 2, the exhaust heat recovery unit 2 a is provided on the exhaust passage 10 through which the exhaust gas from the engine 1 circulates, and is disposed so as to cover the outer wall surface of the exhaust passage 10. A water passage 13 is provided. As shown in FIG. 4, in the cooling water passage 13, the cooling water flows from the cooling water passage 7e as shown by the arrow C1, and the cooling water flows out to the cooling water passage 7e as shown by the arrow C2.

  Unlike the exhaust heat recovery device 2, the exhaust heat recovery device 2 a has a catalyst 11. Specifically, the catalyst 11 is provided inside the exhaust passage 10 covered with the cooling water passage 13. The exhaust gas flowing through the exhaust passage 10 contacts the catalyst 11 and is purified by a chemical reaction such as an oxidation reaction with the catalyst 11. At this time, reaction heat is generated in the catalyst 11 due to a chemical reaction with the exhaust gas.

  By adopting such a structure, the exhaust heat recovery device 2a transmits not only the exhaust heat but also the reaction heat of the catalyst 11 to the cooling water in the cooling water passage 13 through the wall surface of the exhaust passage 10. And efficient heat exchange.

  A catalyst temperature sensor (not shown) for detecting the temperature of the catalyst 11 is attached to the exhaust heat recovery device 2a. The catalyst temperature sensor supplies a detection signal S11 corresponding to the detected temperature to the ECU 50.

  A valve 14 is attached to a branch position between the cooling water passage 7d and the cooling water passage 7e. The valve 14 performs switching of the cooling water passage based on a control signal S14 from the ECU 50. Specifically, the valve 14 switches the route through which the cooling water of the heater core 9 flows between the cooling water passage 7d and the cooling water passage 7e based on the control signal S14. Therefore, the ECU 50 functions as switching control means in the present invention.

  When the engine 1 is not stopped when there is a vehicle warm-up request from the user, the ECU 50 circulates the cooling water between the heater core 9 and the exhaust heat recovery device 2 as in the first embodiment. The coolant of the heater core 9 is circulated through the route of the passage 7d (see FIG. 3). On the other hand, when the engine 1 is stopped, the ECU 50 performs a switching control of the valve 14 so as to circulate the cooling water between the heater core 9 and the exhaust heat recovery device 2a through the route of the cooling water passage 7e. Then, the cooling water of the heater core 9 is circulated (see FIG. 4). The reason for this is as follows.

  When the engine 1 is not stopped, the exhaust gas always flows through the exhaust passage 10. As long as the exhaust gas always flows through the exhaust passage 10, the amount of heat transferred from the exhaust heat recovery device 2 to the cooling water does not decrease with the passage of time. That is, in this case, the cooling water is circulated in the route of the cooling water passage 7d for circulating the cooling water between the heater core 9 and the exhaust heat recovery device 2, so that the heat of the cooling water is radiated by the heater core 9. However, the cooling water is always heated by the exhaust heat of the exhaust gas flowing through the exhaust passage 10, and the temperature of the cooling water does not decrease.

  Therefore, when the engine 1 is not stopped, the ECU 50 controls the valve 14 to cool the coolant in the route of the coolant passage 7d that circulates the coolant between the heater core 9 and the exhaust heat recovery device 2. Circulate.

  On the other hand, when the engine 1 is stopped, no exhaust gas flows in the exhaust passage 10. Therefore, the amount of heat transferred from the exhaust heat recovery device 2 to the cooling water decreases with the passage of time. However, since the exhaust heat recovery device 2 a has the catalyst 11, not only the exhaust heat but also the reaction heat of the catalyst 11 with respect to the cooling water in the cooling water passage 13 through the wall surface of the exhaust passage 10. introduce. Since the heat capacity of the catalyst 11 is greater than the heat capacity of the exhaust gas, the time for which the catalyst 11 retains the reaction heat is longer than the time for which the exhaust gas retains the exhaust heat.

  Therefore, when the engine 1 is stopped, the ECU 50 controls the valve 14 to supply the cooling water through the route of the cooling water passage 7e that circulates the cooling water between the heater core 9 and the exhaust heat recovery device 2a. It will be circulated. By doing in this way, compared with the cooling system which concerns on 1st Embodiment, when an engine stops, the time when the temperature of cooling water becomes below predetermined temperature can be delayed longer.

(Cooling water control process)
Next, a cooling water control method in the cooling system 100b according to the second embodiment will be specifically described with reference to the flowchart shown in FIG. FIG. 5 is a flowchart showing a cooling water control process in the cooling system 100b according to the second embodiment.

  ECU50 will determine whether the engine 1 has stopped, if there exists a vehicle warm-up request | requirement from a user (step S101). Specifically, the ECU 50 determines that the engine 1 has stopped when the ECU 50 itself has transmitted a control signal for stopping to the engine 1. When the ECU 50 determines that the engine 1 is not stopped (step S104), as shown in FIG. 3, the cooling water passage 7d for circulating the cooling water between the heater core 9 and the exhaust heat recovery device 2 is used. The valve 14 is controlled so that the cooling water flows through.

  As described above, when the engine 1 is not stopped, the exhaust gas always flows through the exhaust passage 10 and the exhaust gas always flows through the exhaust passage 10. As long as the heat of the cooling water is radiated by the heater core 9, the cooling water is always heated by the exhaust heat of the exhaust gas flowing through the exhaust passage 10, and the temperature of the cooling water does not decrease. is there.

  If the ECU 50 determines in step S101 that the engine 1 is stopped (step S101: Yes), as shown in FIG. 4, the ECU 50 supplies cooling water between the heater core 9 and the exhaust heat recovery device 2a. The valve 14 is controlled so that the cooling water flows through the circulating cooling water passage 7e (step S102).

  As described above, this is because the exhaust heat recovery device 2a having the catalyst 11 uses only the exhaust heat to the cooling water in the cooling water passage 13 through the wall surface of the exhaust passage 10. This is because the reaction heat of the catalyst 11 is also transmitted, and the time during which the catalyst 11 retains the reaction heat is longer than the time during which the exhaust gas retains the exhaust heat. By doing in this way, in the cooling system 100b which concerns on 2nd Embodiment, compared with the cooling system 100a which concerns on 1st Embodiment, the time when the temperature of cooling water becomes below predetermined temperature is delayed more. Can do. Thereafter, the ECU 50 proceeds to step S103.

  Next, in step S103, the ECU 50 determines whether or not the catalyst temperature of the catalyst 11 is equal to or higher than a predetermined temperature. Specifically, the ECU 50 obtains the catalyst temperature of the catalyst 11 based on the detection signal S11 supplied from the catalyst temperature sensor, and determines whether or not the obtained catalyst temperature is equal to or higher than a predetermined temperature. Specifically, the predetermined temperature is the lowest temperature at which the purification function of the catalyst 11 does not deteriorate. If it is determined in step S103 that the catalyst temperature of the catalyst 11 is equal to or higher than the predetermined temperature, the ECU 50 repeats the process of step S103.

  If the ECU 50 determines in step S103 that the catalyst temperature of the catalyst 11 is lower than the predetermined temperature (step S103: No), the ECU 50 proceeds to step S104. That is, as shown in FIG. 3, the ECU 50 controls the valve 14 so that the cooling water flows through the cooling water passage 7 d that circulates the cooling water between the heater core 9 and the exhaust heat recovery device 2. Thereafter, the ECU 50 ends the cooling water control process.

  That is, when the catalyst temperature of the catalyst 11 becomes lower than the predetermined temperature, the purification function of the catalyst 11 is deteriorated. Therefore, the ECU 50 prevents the cooling temperature of the catalyst 11 from further decreasing. Is switched from the route of the cooling water passage 7e passing through the exhaust heat recovery device 2a to the route of the cooling water passage 7d passing through the exhaust heat recovery device 2. By doing in this way, degradation of the purification function due to a decrease in the catalyst temperature of the catalyst 11 can be suppressed.

It is a figure which shows schematic structure of the cooling system which concerns on each embodiment. It is an enlarged view which shows a part of cooling system which concerns on 1st Embodiment. It is an enlarged view which shows a part of cooling system which concerns on 2nd Embodiment. It is an enlarged view which shows a part of cooling system which concerns on 2nd Embodiment. It is a flowchart which shows the control process of the cooling water which concerns on 2nd Embodiment.

Explanation of symbols

1 engine (internal combustion engine)
2, 2a Exhaust heat recovery device 3 Radiator 4 Thermostat 5 Electric pump (Electric WP)
6 Water temperature sensor 7a, 7b, 7c Cooling water passage 7d Cooling water passage 10 Exhaust passage 11 Catalyst 50 ECU
100 Cooling system

Claims (3)

A first exhaust heat recovery device disposed on an exhaust passage of the internal combustion engine; a first cooling water passage for circulating cooling water between the internal combustion engine and the first exhaust heat recovery device; and a heater core And a cooling system for a hybrid vehicle comprising:
A second cooling water passage that is provided independently of the first cooling water passage and circulates the cooling water between the first exhaust heat recovery device and the heater core;
An electric pump that circulates the cooling water in the second cooling water passage, and a cooling system for a hybrid vehicle. A second exhaust heat recovery device that is disposed on the exhaust passage and has a catalyst that is warmed up by exhaust gas in the exhaust passage;
A third cooling water passage that is provided independently of the first cooling water passage and circulates the cooling water between the second exhaust heat recovery device and the heater core;
A valve for switching a route through which the cooling water of the heater core is circulated between the second cooling water passage and the third cooling water passage;
Switching control means for controlling switching of the valve, and
2. The hybrid vehicle according to claim 1, wherein the switching control unit performs a control of switching a route through which the cooling water of the heater core is circulated to the third cooling water passage when the internal combustion engine is stopped. 3. Cooling system.   The switching means performs control to switch a route through which the cooling water of the heater core is circulated to the second cooling water passage when the temperature of the catalyst is lower than a predetermined temperature. A cooling system for a hybrid vehicle described in 1.

Images