JP2008291690A - Cooling system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling system capable of increasing heating effect of a heater core and suppressing flow resistance in circulating cooling water. <P>SOLUTION: In the cooling system, a cooling water passage to which an exhaust heat recovery device is attached and another cooling water passage to which the heater core is attached are provided in parallel, and the cooling system has two routes of a first route for cooling water passage and a second route for cooling water passage. The first route for cooling water passage is the route in which cooling water is circulated among an internal combustion engine, the exhaust heat recovery device and the heater core. The second route for cooling water passage is the route in which the cooling water is circulated between the exhaust heat recovery device and the heater core. In warming up the internal combustion engine, when heating is required by a user, the route for flow of the cooling water is set at the first route for cooling water passage and is then changed to the second route for cooling water passage. With this, the heating effect by the heater core can be increased and the flow resistance can be suppressed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cooling system that performs heat exchange with an exhaust heat recovery device.

  Conventionally, techniques for exchanging heat between exhaust gas and cooling water to recover exhaust heat have been proposed. For example, Patent Document 1 discloses that when cooling water is heated, heat exchange is performed between the cooling water and the exhaust heat recovery device, thereby enhancing the heating effect. A technique for suppressing heat exchange by bypassing an exhaust heat recovery device is described. Patent Document 2 discloses an exhaust gas recirculation device provided with a cooling water passage that bypasses the heater core.

JP 2006-283711 A JP 2004-285919 A

  However, in the technique described in Patent Document 1, a large amount of cooling water is circulated through the engine, so that the heating effect of the heater core is suppressed. In addition, since the heater core and the exhaust heat recovery device are connected in series, the water flow resistance when circulating the cooling water is increased. In the technique described in Patent Document 2, when the cooling water bypasses the heater core when the engine is warmed up, the cooling water does not flow at all in the heater core, so that the heating does not function.

  The present invention has been made to solve the above-described problems, and provides a cooling system capable of enhancing the heating effect of the heater core and suppressing the water flow resistance when circulating the cooling water. This is the issue.

  In one aspect of the present invention, a cooling system that warms up the internal combustion engine and performs heating by the heater core by circulating cooling water between the internal combustion engine, the exhaust heat recovery device, and the heater core includes the internal combustion engine. On the other hand, a cooling water passage to which the exhaust heat recovery device is attached and a cooling water passage to which the heater core is attached are provided in parallel, and the internal combustion engine, the exhaust heat recovery device and the heater core, A first cooling water passage route through which the cooling water circulates, a second cooling water passage route through which the cooling water circulates between the exhaust heat recovery device and the heater core, and the first A switching means for switching the route through which the cooling water flows between the cooling water passage route and the second cooling water passage route; and a control means for controlling the switching means, the control means comprising the internal combustion engine During warm-up, if there is a heating requirement from the user, the route of flow of the cooling water, after setting the second coolant passage route switches to the first coolant passage route.

  In the cooling system, the cooling water is circulated among the internal combustion engine (engine), the exhaust heat recovery device, and the heater core, so that the internal combustion engine is warmed up and heated by the heater core. The cooling water passage to which the exhaust heat recovery device is attached and the cooling water passage to which the heater core is attached are provided in parallel. The cooling system has two routes, a first cooling water passage route and a second cooling water passage route. The first cooling water passage route is a route through which the cooling water circulates between the internal combustion engine, the exhaust heat recovery device, and the heater core. The second cooling water passage route is a route through which the cooling water circulates between the exhaust heat recovery device and the heater core. The cooling system further includes a switching unit and a control unit. The switching means is, for example, a valve or a three-way valve, and switches the route through which the cooling water flows between the first cooling water passage route and the second cooling water passage route. The control means is, for example, an ECU (Engine Control Unit), and when the internal combustion engine is warmed up, if there is a heating request from a user, a route through which the cooling water flows is set to the second cooling water. After the passage route is set, for example, when the temperature in the vehicle reaches the set temperature requested by the user, the route is switched to the first cooling water passage route. By doing in this way, the cooling system of the present invention can increase the heating effect by the heater core and suppress the water flow resistance when circulating the cooling water, as compared with a general cooling system. Can do.

  According to another aspect of the cooling system, the control unit may change the route of the cooling water to the first cooling when there is no heating request from the user when the internal combustion engine is warmed up. Set to water passage route. Thereby, compared with a general cooling system, the water flow resistance when circulating the cooling water can be suppressed, and warm-up of the engine 1 can be promoted.

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

[First Embodiment]
First, a cooling system according to an embodiment of the present invention will be described. 1 and 2 are diagrams showing a schematic configuration of a cooling system 100 according to an 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 the present 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. The cooling water cools and warms up the engine 1 by passing through the cooling water passages 7a, 7b, 7c, 7d, and 7e.

  The cooling water passage 7 d extends from the engine 1 and is connected to the cooling water passage 7 e via the three-way valve 11. The cooling water passage 7a is connected to the cooling water passage 7e. The cooling water passage 7 c is connected to the cooling water passage 7 a, the cooling water passage 7 b extending from the cooling water passage 7 e, and the thermostat 4. The cooling water passage 7 c communicates with the engine 1. Here, the radiator 3 is provided on the cooling water passage 7b.

  The cooling water passage 7e is configured to branch again into the cooling water passage 7e1 and the cooling water passage 7e2 and then merge again. That is, the cooling water passage 7e1 and the cooling water passage 7e2 are connected to the engine 1. The configuration is provided in parallel. Specifically, the cooling water passage 7e1 and the cooling water passage 7e2 are connected via the cooling water passage 7d and the three-way valve 11. The electric WP 8 and the exhaust heat recovery device 2 are provided on the cooling water passage 7e1, and the heater core 9 is provided on the cooling water passage 7e2. The cooling water passage 7b branches off from the cooling water passage 7e1.

  A cooling water passage 7e3 is provided to connect the cooling water passage 7e1 and the cooling water passage 7e2. The valve 10 is provided on the cooling water passage 7e3, and the flow rate of the cooling water in the cooling water passage 7e3 can be controlled by opening and closing. The valve 10 opens and closes the valve based on a control signal S10 from the ECU 50.

  The three-way valve 11 has a cooling water inlet / outlet in three directions, and an openable / closable valve at the inlet / outlet in each direction. In the example shown in FIG. 1, the three-way valve 11 has a cooling water inlet / outlet in each direction of the cooling water passages 7d, 7e1, 7e2, and a valve is provided at the inlet / outlet of each direction of the cooling water passages 7d, 7e1, 7e2. Have. The three-way valve 11 opens and closes the inlet / outlet valves in each direction based on a control signal S11 from the ECU 50.

  Hereinafter, when the cooling water passages 7a to 7e are not distinguished from each other, they are simply used as the cooling water passage 7.

  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 cooling water flows into the engine 1 from the cooling water passage 7c.

  The coolant flowing into the engine 1 passes through a water jacket (not shown) inside the engine 1 and then flows out from the coolant passage 7d. The water jacket is provided around a cylinder (not shown) inside the engine 1, and the cylinder is warmed up by exchanging heat with cooling water passing through the water jacket.

  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. Thereby, the cooling water is heated.

  The electric pump (hereinafter referred to as “electric WP”) 8 includes an electric motor, and circulates cooling water in the cooling water passage 7 by driving the motor. Specifically, the electric WP 8 is supplied with electric power from a battery, and the rotation speed and the like are controlled by a control signal S 8 supplied from the ECU 50.

  The heater core 9 is a device (heating device) that warms the air in the passenger compartment 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).

  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 thermostat 4 is configured by a valve that opens and closes according to the temperature of the cooling water. Basically, the thermostat 4 opens when the temperature of the cooling water 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.

  On the other hand, when the temperature of the cooling water is relatively low, the thermostat 4 is closed. In this case, the cooling water does not pass through the radiator 3. Thereby, since the temperature fall of a cooling water is suppressed, the overcool of the engine 1 is suppressed.

  The ECU (Engine 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 controls the valve 10 and the three-way valve 11 based on detection signals supplied from various sensors (not shown).

(Control method for cooling water)
Next, a cooling water control method will be described. The solid line arrows in FIG. 1 indicate the flow of cooling water when the valve 10 is open and the three-way valve 11 is open on the cooling water passages 7d and 7e1 and the cooling water passage 7e2 is closed (hereinafter referred to as the flow of cooling water). , The passage route through which the cooling water flows is referred to as “first passage passage of the cooling water”). The solid line arrow in FIG. 2 indicates the flow of cooling water when the valve 10 is closed and the three-way valve 11 is opened on the cooling water passages 7e1 and 7e2 and the cooling water passage 7d is closed (hereinafter referred to as the cooling water flow). The passage route through which the cooling water flows is referred to as “second passage route of the cooling water”).

  First, the passage route of the first cooling water will be described with reference to FIG. At this time, in the three-way valve 11, the valves on the cooling water passages 7d and 7e1 side are opened, and the valve on the cooling water passage 7e2 side is closed. Therefore, as shown in FIG. 1, all the cooling water flowing out from the cooling water passage 7d flows into the cooling water passage 7e1 and is pushed out by the electric WP 8, but does not flow into the cooling water passage 7e2. When the valve 10 is opened, the cooling water also flows from the cooling water passage 7e1 to the cooling water passage 7e3. Therefore, the cooling water pushed out by driving the electric WP 8 advances in two routes. One is a route that travels through the cooling water passage 7e1, passes through the exhaust heat recovery device 2, and reaches the cooling water passage 7a. The other is a route that travels from the cooling water passage 7e1 to the cooling water passage 7e3. This is a route that reaches the cooling water passage 7a after passing through the heater core 9 on the cooling water passage 7e2. In the three-way valve 11, since the valve on the cooling water passage 7e2 side is closed, the cooling water does not flow in the direction from the cooling water passage 7e3 toward the three-way valve 11 of the cooling water passage 7e1. The cooling water that has passed through these two routes merges when it reaches the cooling water passage 7a, passes through the cooling water passages 7a and 7c, and flows into the water jacket inside the engine 1. Then, after passing through a water jacket (not shown) inside the engine 1, the cooling water flows out of the cooling water passage 7d, flows again into the cooling water passage 7e1, and is pushed out by the electric WP8.

  Next, the passage route of the second cooling water will be described with reference to FIG. As shown in FIG. 2, when the valve 10 is closed, the cooling water does not flow into the cooling water passage 7e3. Therefore, the cooling water pushed out by driving the electric WP 8 travels through the cooling water passage 7 e 1 and passes through the exhaust heat recovery device 2. At this time, in the three-way valve 11, the valves on the cooling water passages 7e1 and 7e2 side are open and the valve on the cooling water passage 7d side is closed, so that the cooling water in the water jacket inside the engine 1 does not flow. Therefore, the cooling water that has passed through the exhaust heat recovery device 2 does not proceed to the cooling water passage 7 a but proceeds to the cooling water passage 7 e 2 and passes through the heater core 9. The cooling water that has passed through the heater core 9 advances through the cooling water passage 7e2, then goes to the cooling water passage 7e1, and is pushed out again by the electric WP8.

  That is, in the cooling system 100 according to the present embodiment, the valve 10 is opened, and the three-way valve 11 includes a valve on the cooling water passage 7d side and a valve on the cooling water passage 7e1 side where the electric WP 8 is installed. By opening and closing the valve on the side of the cooling water passage 7e2, the exhaust heat recovery device 2 and the heater core 9 are connected in parallel, and the cooling water flows between the engine 1, the exhaust heat recovery device 2 and the heater core 9. Circulate with. Accordingly, the first coolant passage route (solid arrow in FIG. 1) is the first coolant passage route of the present invention. Further, when the valve 10 is closed and the three-way valve 11 is opened, the valves on the cooling water passages 7e1 and 7e2 side are opened and the valve on the cooling water passage 7d side leading to the engine 1 is closed. The cooling water is circulated between the exhaust heat recovery device 2 and the heater core 9. Accordingly, the second cooling water passage route (solid arrow in FIG. 2) is the second cooling water passage route of the present invention. Further, the valve 10 and the three-way valve 11 function as switching means in the present invention, and the ECU 50 functions as control means in the present invention.

  In a general cooling system applied to a general vehicle, when the user requests heating when the engine is warmed up, the heating is operated until the temperature of the cooling water reaches a predetermined temperature (for example, 40 ° C.). In other words, the blower in the heater core does not operate. Therefore, even if the user operates the air conditioner and tries to warm the interior of the vehicle by heating, it becomes necessary to wait for the time until the entire amount of cooling water is heated to reach a predetermined temperature, and the heating effect of the heater core is increased. It will be suppressed. In addition, since the heater core and the exhaust heat recovery device are connected in series, when the cooling water is circulated between the engine, the heater core, and the exhaust heat recovery device, the water flow resistance increases.

  Therefore, in the cooling system 100 according to the present embodiment, the ECU 50 sets the route through which the coolant flows as the second coolant passage route when the user requests heating when the engine 1 is warmed up. After that, the first cooling water passage route is switched.

  Specifically, the ECU 50 controls the valve 10 and the three-way valve 11 when the user requests heating when the engine 1 is warmed up, and passes the second coolant through the route through which the coolant flows. Set to root. As a result, only the cooling water in the cooling water passages 7e1 and 7e2 circulates between the exhaust heat recovery device 2 and the heater core 9 as shown by the solid arrows in FIG. Compared with a general cooling system that is heated, the temperature of the cooling water that passes through the heater core is increased quickly, and the time required to reach a predetermined temperature at which the blower operates can be shortened. Thus, in the cooling system 100 according to the present embodiment, the heating effect by the heater core can be enhanced as compared with a general cooling system.

  When the ECU 50 determines, for example, that the temperature inside the vehicle is a set temperature requested by the user by a temperature sensor (not shown) that measures the temperature inside the vehicle, the ECU 50 sets the valve 10 and the three-way valve 11. By controlling, the route through which the cooling water flows is switched from the second cooling water passage route to the first cooling water passage route. As a result, as shown by the solid line arrow in FIG. 1, the cooling water flows separately in a route passing through the exhaust heat recovery device 2 and a route passing through the heater core 9, so that the exhaust heat recovery device and the heater core are connected in series. Compared with a general cooling system in which cooling water passes through the route connected to, the water flow resistance when circulating the cooling water can be suppressed, and the driving force of the electric WP 8 can be reduced.

  In the cooling system 100 according to the present embodiment, the ECU 50 controls the valve 10 and the three-way valve 11 when the user does not request heating when the engine 1 is warmed up, and the route through which the cooling water flows. Is set as the first coolant passage route from the beginning. Thereby, as also stated above, compared with a general cooling system, the water flow resistance when circulating the cooling water can be suppressed.

  At this time, the cooling water heated by the exhaust heat recovery device 2 passes from the cooling water passage 7e1 to the cooling water passage 7a, and hardly passes from the cooling water passage 7e1 to the cooling water passage 7e2. . This is because there is a flow of cooling water that passes from the cooling water passage 7e2 to the cooling water passage 7a as shown in FIG. Accordingly, the cooling water heated by the exhaust heat recovery device 2 proceeds from the cooling water passage 7e1 to the cooling water passage 7a and flows into the engine 1 through the cooling water passage 7c. That is, the amount of heat recovered in the exhaust heat recovery device 2 is not radiated by the heater core 9 before being radiated by the engine 1. Therefore, in the cooling system 100 according to the present embodiment, most of the amount of heat recovered in the exhaust heat recovery unit 2 can be used for warming up the engine 1, so that the cooling water causes the exhaust heat recovery unit and the heater core to be used together. As compared with a general cooling system that flows into the engine after passing through a route connected in series, warm-up of the engine 1 can be promoted.

  Note that the cooling system of the present invention is not limited to the illustrated examples shown in FIGS. 1 and 2, and it is needless to say that various modifications can be made without departing from the scope of the present invention. For example, although the electric WP 8 is provided on the cooling water passage 7e1, the electric WP 8 is not limited to this. Instead, the electric WP 8 may be provided on the cooling water passage 7e2 (position of the broken line 8a in FIG. 1). In this case, the cooling water passage 7b leading to the radiator 3 is branched from the cooling water passage 7e2. In this case, the valve 10 is opened, and in the three-way valve 11, the valve on the cooling water passage 7d side and the valve on the cooling water passage 7e2 side where the electric WP 8 is installed are opened and the cooling water passage 7e1 side is opened. When the valve is closed, the exhaust heat recovery device 2 and the heater core 9 are connected in parallel, and the cooling water circulates between the engine 1, the exhaust heat recovery device 2 and the heater core 9 (first Cooling water passage route). Further, when the valve 10 is closed and the three-way valve 11 is opened, the valves on the side of the cooling water passages 7e1 and 7e2 are opened and the valve on the side of the cooling water passage 7d leading to the engine 1 is closed. 9 is connected in series, and the cooling water circulates between the exhaust heat recovery device 2 and the heater core 9 (second cooling water passage route). Even if it does in this way, it cannot be overemphasized that the effect similar to the effect of this invention mentioned above is acquired.

It is a figure which shows schematic structure of the cooling system which concerns on this embodiment. It is a figure which shows schematic structure of the cooling system which concerns on this embodiment.

Explanation of symbols

1 engine (internal combustion engine)
2 Exhaust heat recovery device 3 Radiator 4 Thermostat 8 Electric pump (Electric WP)
7 Cooling water passage 9 Heater core 10 Valve 11 Three-way valve

Claims (2)

A cooling system that warms up the internal combustion engine and heats the heater core by circulating cooling water between the internal combustion engine, the exhaust heat recovery device, and the heater core,
For the internal combustion engine, a cooling water passage to which the exhaust heat recovery device is attached and a cooling water passage to which the heater core is attached are provided in parallel.
A first coolant passage route through which the coolant circulates between the internal combustion engine, the exhaust heat recovery unit and the heater core;
A second coolant passage route through which the coolant circulates between the exhaust heat recovery device and the heater core;
Switching means for switching a route through which the cooling water flows between the first cooling water passage route and the second cooling water passage route;
Control means for controlling the switching means,
When the internal combustion engine is warmed up, and when there is a heating request from the user, the control means sets the route through which the cooling water flows to the second cooling water passage route, and then A cooling system characterized by switching to a cooling water passage route.   The control means sets the route through which the cooling water flows to the first cooling water passage route when there is no heating request from the user when the internal combustion engine is warmed up. Item 4. The cooling system according to Item 1.

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