JP2008232031A - Exhaust heat recovery device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To materialize efficient and effective recovery and use of exhaust heat. <P>SOLUTION: A vehicle 10 is provided with an exhaust heat recovery system 300. An exhaust heat recovery apparatus 360 and an EGR cooler 370 are arranged in a supply route of cooling water in series with a heater core 350 and mutually in parallel in the exhaust heat recovery system 300. A flow rate ratio control valve 380 varying flow rate ratio of cooling water among a plurality of exhaust heat collecting means is installed between the heater core 350 and the exhaust heat recovery means. ECU 100 controls an operation state of flow rate ratio control valve 380 by executing flow rate ratio control process. Each operation mode of a low water temperature mode, a middle water temperature mode, high water temperature mode or a very high water temperature mode is selected and executed according to cooling water temperature Thw, flow rate ratio between the exhaust heat recovery apparatus 360 and the EGR cooler 370 are optimized and flow rate of cooling water is optimized in each operation mode. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technical field of an exhaust heat recovery device capable of recovering exhaust heat of an internal combustion engine.

  As this type of apparatus, an apparatus provided with an EGR (Exhaust Gas Recirculation) cooler has been proposed (see, for example, Patent Document 1). According to the exhaust heat recovery system disclosed in Patent Document 1 (hereinafter referred to as “conventional technology”), the cooling water heated by heat exchange with the EGR cooler is supplied to the heater core, thereby heating the heater core. It is said that rapid heating can be performed even when the ability is insufficient, and passenger comfort can be improved.

  In addition, in the cooling circuit structure in which the heater core and the heat accumulator are arranged in parallel, an apparatus for heating with high-temperature cooling water stored in the heat accumulator when the engine is stopped has been proposed (for example, see Patent Document 2).

JP 2005-173582 A JP-A-9-272327

  The combustion of an internal combustion engine is not stable in a situation where engine warm-up is insufficient, such as at the time of starting. Usually, in such a period in which combustion is not stable, use of EGR that can further deteriorate the combustibility is not performed. When the EGR device is not used, the EGR cooler naturally does not recover the exhaust heat. Therefore, it is difficult to give exhaust heat to the cooling water in a situation where engine warm-up is insufficient. For this reason, when viewed from the viewpoint of warming up the internal combustion engine, the conventional technique does not always work effectively. In other words, the conventional technique has a technical problem that it is difficult to achieve both heating in the vehicle and engine warm-up in some cases.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an exhaust heat recovery apparatus capable of realizing efficient and effective recovery and use of exhaust heat.

  In order to solve the above-described problems, an exhaust heat recovery apparatus according to the present invention is an exhaust heat recovery apparatus that recovers exhaust heat related to exhaust gas from an internal combustion engine in a vehicle including an internal combustion engine and a heater core as a cooling water supply target. A plurality of exhaust heat recovery means capable of recovering the exhaust heat, arranged in series with the heater core as a part of the supply target and in parallel with the heater core, and the exhaust heat And a flow rate ratio changing means capable of changing the flow rate ratio of the cooling water between the recovery means.

  According to the exhaust heat recovery apparatus of the present invention, in the cooling water supply path, the flow rate of the cooling water in each of the plurality of exhaust heat recovery means arranged in series with the heater core and in parallel with each other is the flow rate ratio. It can be changed by changing means. Therefore, the flow rate of the cooling water supplied to each exhaust heat recovery means can be individually optimized.

  Therefore, according to the exhaust heat recovery apparatus according to the present invention, heat exchange with the cooling water is effectively performed in the heater core arranged in series with the plurality of exhaust heat recovery means (that is, sufficient heat is supplied to the heater core. Each of the plurality of exhaust heat recovery means is arranged in parallel with each other, and the flow resistance is reduced. It is possible to appropriately control the flow rate of the cooling water that can be used for heat exchange in. That is, the exhaust heat can be efficiently and effectively recovered and used.

  In one aspect of the exhaust heat recovery apparatus according to the present invention, specifying means for specifying an operating condition of the internal combustion engine including at least the temperature of the cooling water, the flow rate ratio and the plurality of the plurality of operating conditions based on the specified operating condition Setting means for setting at least one of the flow rates of the cooling water to be supplied to at least a part of the exhaust heat recovery means, and a first control for controlling the flow rate ratio changing means according to the set at least one Means.

  According to this aspect, the flow rate ratio set based on the operating conditions of the internal combustion engine including the cooling water temperature or the flow rate of the cooling water to be supplied to at least part of the plurality of exhaust heat recovery means, or both Accordingly, the flow rate ratio changing means is controlled. Therefore, the individual exhaust heat recovery means can be functioned more efficiently and effectively.

  In this aspect, the supply means capable of supplying the cooling water to the supply path independently from the engine rotation of the internal combustion engine, and the second control for controlling the supply means according to at least one of the set values. And a means.

  In this case, the flow rate of the cooling water to be supplied to each of the exhaust heat recovery means can be controlled substantially freely. Therefore, while enjoying the benefits of the waste heat recovery means being arranged in parallel with each other, the practically high benefit is provided in that the flow rate corresponding to each individual waste heat recovery means can be freely controlled. Is done.

  In this aspect, the plurality of exhaust heat recovery means include an EGR cooler capable of cooling EGR gas recirculated to the intake system of the internal combustion engine, and exhaust heat capable of heating the cooling water by the recovered exhaust heat. A collector may also be included.

  When the EGR cooler is provided as the exhaust heat recovery means, the exhaust as EGR gas recirculated to the intake system as a concept including the intake pipe, the intake manifold, the intake port, etc. can be cooled by heat exchange with the cooling water. This is preferable because it prevents a decrease in the performance of the internal combustion engine due to a decrease in intake efficiency or the like. Further, when an exhaust heat recovery device is provided as an exhaust heat recovery means, the heat recovered from the exhaust heat when the internal combustion engine is not warmed up, such as at the time of start-up, is applied to the cooling water, so that the internal combustion engine can be warmed up early. It is effective in that it can be achieved.

  On the other hand, the operating conditions between the EGR cooler and the exhaust heat recovery unit can vary greatly. For example, if the EGR gas is recirculated to the intake system when the engine is not warmed up, the combustibility may be further deteriorated. Therefore, the EGR device is generally in a non-operating state when the engine is not warmed up. On the other hand, if the exhaust heat recovery unit is used even after warming up (that is, if the heat supply to the cooling water is continued), the temperature of the cooling water is merely increased without meaning, and eventually the heat radiation means such as a radiator is frequently used. It only encourages proper use. If the operating conditions related to the plurality of exhaust heat recovery means can be relatively different in this way, the practical benefit brought about by the synergistic effect of the flow rate ratio changing means and the supply means will be great.

  In one aspect of the exhaust heat recovery apparatus according to the present invention including an EGR cooler and an exhaust heat recovery device, the setting means is configured to increase the specified cooling water when the temperature of the cooling water is low. The flow rate ratio corresponding to at least the exhaust heat recovery device is set according to the temperature.

  In this case, since the flow rate ratio corresponding to at least the exhaust heat recovery device is set so as to increase when the temperature of the cooling water is low, warming up of the internal combustion engine can be promoted, which is beneficial in practice.

  In another aspect of the exhaust heat recovery apparatus according to the present invention including an EGR cooler and an exhaust heat recovery device, the setting means is configured to increase the specified cooling water so as to increase when the temperature of the cooling water is high. The flow rate ratio corresponding to at least the EGR cooler is set according to the temperature.

  In this case, since the flow rate ratio corresponding to at least the EGR cooler is set so as to increase when the temperature of the cooling water is high, the EGR gas can be effectively cooled, which is useful in practice.

  In another aspect of the exhaust heat recovery apparatus according to the present invention including an EGR cooler and an exhaust heat recovery device, the specifying means specifies a load state of the internal combustion engine as a part of the operating condition, and the setting means includes When the specified load state corresponds to a predetermined high load state, at least one is set so that the exhaust heat recovery device is cooled at least in preference to the EGR cooler.

  In this case, cooling of the exhaust heat recovery device can be prioritized over cooling of the EGR cooler, so that the exhaust heat recovery device is prevented from falling into an excessively high temperature state, which is useful in practice.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

<Embodiment of the Invention>
<First Embodiment>
<Configuration of Embodiment>
First, the configuration of the vehicle 10 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram conceptually showing the configuration of the vehicle 10.

  In FIG. 1, the vehicle 10 includes an ECU 100, an engine 200, and an exhaust heat recovery system 300.

The ECU 100 is an electronic control unit that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown) and is configured to be able to control the entire operation of the vehicle 10. ,
Each of the “specifying means”, “setting means”, “first control means”, and “second control means” according to the present invention is configured to function as an example. It should be noted that the physical, mechanical, mechanical, or electrical configuration of each means according to the present invention is not limited to the ECU 100 that is integrally configured in hardware as long as the function according to the means can be realized. For example, different hardware configurations may be adopted, and various other processing units, various controllers, various computer systems such as a microcomputer device, and the like may be employed. The ECU 100, together with the exhaust heat recovery system 300, constitutes an example of an “exhaust heat recovery device” according to the present invention, and can execute a flow rate ratio control process, which will be described later, according to a control program stored in the ROM. Configured to be possible.

  The engine 200 is a gasoline engine as an example of the “internal combustion engine” according to the present invention. The “internal combustion engine” according to the present invention is, for example, a mixture of various fuels such as gasoline or various alcohols and intake air in a combustion chamber in each of the plurality of cylinders. Includes engines that can output power as explosive power generated when the air-fuel mixture burns, as appropriate, via a mechanical transmission path such as a piston and connecting rod, for example, via an output shaft such as a crankshaft. This is a concept that preferably includes, for example, a 2-cycle or 4-cycle reciprocating engine. Here, a detailed configuration of the engine 200 will be described with reference to FIG. Here, FIG. 2 is a schematic diagram of the engine 200. In FIG. 2, the same reference numerals are given to the same portions as those in FIG. 1, and the description thereof is omitted as appropriate.

  In FIG. 2, an engine 200 burns an air-fuel mixture through an ignition operation by an ignition device 202 in which a part of a spark plug (not shown) is exposed in a combustion chamber in a cylinder 201, and an explosive force due to such combustion. The reciprocating motion of the piston 203 that occurs in response to the above is converted into the rotational motion of the crankshaft 205 via the connecting rod 204. A crank position sensor 206 that detects the rotational position (ie, crank angle) of the crankshaft 205 is installed in the vicinity of the crankshaft 205. The crank position sensor 206 is electrically connected to the ECU 100, and the ECU 100 is configured to be able to control the ignition timing and the like of the ignition device 202 based on the crank angle detected by the crank position sensor 206. Yes. Further, the ECU 100 is configured to be able to calculate the engine speed NE of the engine 200 based on the rotational position of the crankshaft 205. The engine 200 is an in-line four-cylinder engine in which four cylinders 201 are arranged in series in a direction perpendicular to the paper surface. However, since the configurations of the individual cylinders 201 are equal to each other, in FIG. Only the cylinder 201 will be described.

  In the engine 200, the air sucked from the outside passes through the intake pipe 207 and is mixed with the fuel injected from the injector 212 in the intake port 210 to become the above-mentioned air-fuel mixture. The fuel is stored in a fuel tank (not shown), and is pumped and supplied to the injector 212 via a delivery pipe (not shown) by the action of a feed pump (not shown). The injector 212 is electrically connected to the ECU 100, and is configured to be able to inject the supplied fuel into the intake port 210 in accordance with the control of the ECU 100. The form of the injection means for injecting the fuel does not have to adopt a so-called intake port injector configuration as shown in the figure. For example, the pressure of fuel pumped by a feed pump or other low-pressure pump is further increased by a high-pressure pump. It may have a form such as a so-called direct injection injector configured to be able to directly inject fuel into the high-temperature and high-pressure cylinder 201.

  The communication state between the inside of the cylinder 201 and the intake pipe 207 is controlled by opening and closing the intake valve 211. The air-fuel mixture combusted inside the cylinder 201 becomes exhaust and is led to the exhaust pipe 215 via the exhaust port 214 when the exhaust valve 213 that opens and closes in conjunction with opening and closing of the intake valve 211 is opened.

  On the other hand, on the upstream side of the intake port 210 in the intake pipe 207, a throttle valve 208 for adjusting the intake air amount related to the intake air guided through a cleaner (not shown) is disposed. At this time, the intake air amount is detected by an air flow meter (not shown) and is grasped by the ECU 100 electrically connected to the air flow meter.

  The slot valve motor 209 is a motor that is electrically connected to the ECU 100 and configured to drive the throttle valve 208. The ECU 100 is configured to be able to control the drive state of the throttle valve motor 209 based on an access opening (not shown) detected by an accelerator position sensor (not shown) provided in the vehicle 10, thereby The opening / closing state of the valve 208 (that is, the throttle opening) is controlled. The throttle valve 208 is a kind of electronically controlled throttle valve as described above, and the throttle opening can be controlled by the ECU 100 regardless of the driver's intention (that is, the accelerator opening).

  A three-way catalyst 216 is installed in the exhaust pipe 215. The three-way catalyst 216 is a catalyst capable of purifying CO (carbon monoxide), HC (hydrocarbon), and NOx (nitrogen oxide) discharged from the engine 200, respectively. A water temperature sensor 217 for detecting a cooling water temperature Thw related to cooling water (LLC) that is circulated and supplied to cool the engine 200 is disposed in the water jacket installed in the cylinder block that houses the cylinder 201. Has been. The water temperature sensor 217 is electrically connected to the ECU 100, and the detected cooling water temperature Thw is grasped by the ECU 100 constantly or at a constant or indefinite period.

  On the other hand, an exhaust heat recovery device 360 is installed downstream of the three-way catalyst 216 in the exhaust pipe 215. The exhaust heat recovery unit 360 is an example of the “exhaust heat recovery means” according to the present invention configured to be able to recover exhaust heat from the high-temperature exhaust led into the exhaust pipe 215. The exhaust heat recovery device 360 has a structure in which a plurality of stainless steel matrix members (or mesh members) as heat storage materials are stacked, and heat transfer from the exhaust gas when the exhaust gas passes through the matrix member. It is possible to take away at least a part of the exhaust heat through the air. At this time, the flow loss and the pressure loss of the exhaust heat recovery device 360 are determined so that the magnitude of the exhaust resistance does not become practical.

  In the present invention, “recovering exhaust heat” means, for example, exhaust gas guided to an exhaust system as a concept including various parts such as an exhaust port, an exhaust manifold, and an exhaust pipe located downstream of these. Including at least taking a part of the exhaust heat, and as a preferred form, at least a part of the taken exhaust heat is temporarily stored, for example, through some heat storage means, or such Including heat treatment as a concept including spatial radiation, physical heat transfer, etc. directly with the cooling water without going through a heat storage process, etc. Is a broad concept including, for example, converting the exhaust heat thus taken into mechanical energy, converting it into electrical energy through a heat pump, a thermoelectric conversion module, or the like. As long as such a concept can be satisfied, the physical, mechanical, mechanical, electrical, or chemical configuration of the exhaust heat recovery means in the exhaust heat recovery apparatus according to the present invention is not limited.

  Further, an EGR pipe 218 is branched from the exhaust pipe 215 downstream of the exhaust port 214 and communicates with the intake port 210 upstream of the intake pipe 207. An EGR valve 219 is installed on the EGR pipe 218. The EGR valve 219 is an electromagnetic on-off valve that is electrically connected to the ECU 100 and configured to be controlled by the ECU 100. The EGR valve 219 has a physical configuration in which the opening degree that defines the open / close state can continuously change.

  The EGR valve 219 and the EGR pipe 218 constitute a so-called EGR device, and are configured to be able to recirculate a part of the exhaust gas guided to the exhaust pipe 215 to the intake system as EGR gas. At this time, the flow rate of the EGR gas is controlled by the EGR valve 219.

  On the other hand, an EGR cooler 370 is installed upstream of the EGR valve 219 in this EGR pipe 218 (in this case, on the exhaust pipe side). The EGR cooler 370 is one of the elements constituting the EGR device, and is configured to be able to cool the EGR gas by heat exchange between the EGR gas and the cooling water. As another example.

  Returning to FIG. 1, the exhaust heat recovery system 300 includes a cooling water circulation path 310, an electric W / P 320, a thermostat 330, a radiator 340, a heater core 350, a flow rate control valve 380, and the above-described exhaust heat recovery device 360 and EGR cooler 370. Consists of.

  The cooling water circulation path 310 includes the above-described water jacket stretched around the cylinder block of the engine 200, and a cooling water supply path appropriately discharged by the electric W / P 320 (that is, the “supply path” according to the present invention). For example, it is a pipe made of metal or resin.

  The cooling water circulation path 310 is disposed upstream of the main circulation path 310d and the heater core 350 through the electric W / P 320, the engine 200 (mainly a water jacket), the heater core 350, the exhaust heat recovery device 360, and the EGR cooler 370 to the thermostat 330. A radiator bypass passage 310a branched from the main circulation passage 310d to the thermostat 330, a radiator inlet 310b branched from the water jacket of the engine 200 to guide the cooling water to the radiator 340, and the cooling water after passing through the radiator 340 is supplied to the electric W / P320 is recirculated from the main circulation path 310d at the radiator outlet 310c and the flow rate control valve 380, and passes through the exhaust heat recovery device 360 and the EGR cooler 370, respectively, and then returns to the main circulation path 310d. Configured to include a branch passage 210e and 310f to flow.

  The electric W / P 320 is a spiral electric pump. The electric W / P 320 is configured to be able to suck the cooling water by the rotational force of a motor (not shown) and discharge the cooling water in an amount corresponding to the rotational speed of the motor.

  Here, the electric W / P 320 is configured to be able to supply the cooling water independently of the engine rotation of the internal combustion engine, and is an example of the “supply means” according to the present invention. Note that “independent of the engine rotation of the internal combustion engine” according to the present invention refers to, for example, rotation according to the rotational state of the crankshaft (crankshaft 205 in this embodiment) of the internal combustion engine (engine 200 in this embodiment). This is a concept indicating that the state cannot be uniquely determined, and indicates that the supply amount of the cooling water can be controlled without being influenced by the engine rotation of the internal combustion engine. Therefore, as long as it does not violate such a concept, the aspect of the “supply means” according to the present invention is not limited to the electric W / P 320, and is connected to, for example, the crankshaft 205, and a part of the rotational driving force of the crankshaft 205 It is possible to rotate using the rotation, and to control the rotation speed related to the rotation by variably controlling the engagement force in the physical engagement means such as a clutch in a binary, stepwise or continuous manner. It may be a mechanical pump or the like configured to be capable of being controlled in a binary, stepwise or continuous manner.

  In the electric W / P 320, the motor is supplied with electric power from a power supply source (not shown) (for example, a vehicle-mounted 12V battery or other battery) and supplied via a motor drive system (not shown). According to the duty ratio of (or current), the rotation speed is controlled to increase or decrease. Further, the motor drive system is in a state of being electrically connected to the ECU 100, and the operation state including the above-described duty ratio is controlled by the ECU 100. That is, the operation state of the electric W / P 320 is controlled by the ECU 100.

  In addition, when the supply means which concerns on this invention is comprised as an electric drive type pump illustrated by this electric W / P320, for example, the electric power and voltage supplied via such an electric power supply source and a motor drive system Alternatively, various control amounts such as currents or duty ratios corresponding thereto are detected according to various operating conditions of the internal combustion engine, such as engine speed and / or load, or detected by a rotation sensor or the like. It is possible to accurately and easily control the motor rotation speed, the motor rotation speed, the pump rotation speed, or the like to a target value by feeding back the motor rotation speed to the various control amounts.

  Further, when the supply means according to the present invention has an aspect in which the engagement force can be changed like the electric W / P 320 or the engagement means described above, the supply amount (discharge amount) of the cooling water is substantially equal to the engine 200. The degree of freedom in control is accordingly increased. In particular, an electrically driven pump is preferable because it can be driven even if the engine 200 is stopped in an extreme case.

  The thermostat 330 is temperature adjusting means provided to stabilize the cooling water temperature Thw. Inside the thermostat 330, a control valve for controlling the communication state between the radiator outlet 310c and the main circulation path 310d described above is provided. When the control valve is in the open state, the thermostat 330 guides the cooling water to the radiator 340 via the radiator inlet 310b, and the cooling water after passing through the radiator 340 is supplied to the main circulation path via the radiator outlet 310c. It is configured to be able to reflux to 310d. The thermostat 330 is electrically connected to the ECU 100, and the open / close state of the control valve is controlled to the upper level by the ECU 100. In this embodiment, when the cooling water temperature Thw reaches 80 ° C., the valve body of the control valve is driven and controlled by the ECU 100 so that the cooling water is provided for heat dissipation by the radiator 340.

  The thermostat 330 has a control valve for controlling the communication state between the radiator bypass passage 310a and the main circulation passage 310d in addition to the control valve for controlling the communication state between the radiator outlet 310c and the main circulation passage 310d. One of the control valves may be configured to be opened. Alternatively, a three-way valve may be provided instead of such a plurality of control valves, and an operation equivalent to the operation of the control valve described above may be realized. That is, when the cooling water is used for heat radiation by the radiator 340, the radiator bypass passage 310a may be used in combination, or the use of the radiator bypass passage 310a may be stopped.

  The radiator 340 includes a plurality of water pipes arranged in communication with the radiator inlet 310b and the radiator outlet 310c. The radiator 340 includes a plurality of corrugated fins on the outer periphery of the water pipe. When the water flows, the cooling water can be relatively cooled by heat exchange with the atmosphere via the fins, that is, by radiating the heat of the cooling water to the outside. Therefore, the temperature of the cooling water discharged from the radiator outlet 310c is lower than that of the cooling water flowing into the radiator 340 via the radiator inlet 310b.

  The heater core 350 is configured to function as a heat source of a heating device (not shown). The heater core 350 is installed on the main circulation path 310d of the cooling water circulation path 310, and is configured to be able to exchange heat with the cooling water supplied to the main circulation path 310d. On the other hand, the heater core 350 communicates with an air conditioning duct (not shown) of the vehicle 10 and is configured to be able to raise the temperature of air sucked into the air conditioning duct by heat acquired by heat exchange with cooling water. Has been.

  The flow rate control valve 380 is an electromagnetic on-off valve that is electrically connected to the ECU 100 and is configured to be electrically controlled by the ECU 100 as an example of the “flow rate changing means” according to the present invention. is there. The flow rate ratio control valve 380 is configured to be able to change a flow rate ratio that is a ratio between the flow rate of the cooling water flowing through the branch path 310e and the flow rate of the cooling water flowing through the branch path 310f according to the open / closed state. ing. The ECU 100 holds in advance a control map that prescribes the relationship between the energization amount to the flow rate control valve 380 and the flow rate ratio, and selects one energization amount from the map to select the flow rate control valve 380. By being subjected to the energization control, the flow rate ratio between the branch pipe 310e and the branch pipe 310f can be controlled to a desired value. This flow rate ratio is controlled by a flow rate control process.

  Note that the flow rate ratio changing means according to the present invention is capable of changing the flow rate of the cooling water between the plurality of exhaust heat recovery means, for example, stepwise or continuously, for example, depending on the open / closed state. However, the configuration of the flow rate control valve 380 may not be employed, and various other movable valve devices such as a butterfly valve may be employed. Although the flow rate ratio is changed, the actual flow rate ratio is not necessarily controlled quantitatively. For example, the flow rate ratio may be qualitatively controllable only for the flow rate ratio.

<Operation of Embodiment>
<Outline of flow ratio control process>
Here, in view of the fact that the plurality of exhaust heat recovery means (EGR cooler 370 and exhaust heat recovery device 360 in this embodiment) are arranged in parallel with each other in the cooling water supply path, one exhaust heat recovery unit is provided. Even if there is a situation where exhaust is not supplied to the means (for example, the EGR cooler is not supplied with exhaust when the EGR valve 219 is fully closed and the EGR device is not in operation), the exhaust is supplied to other exhaust heat recovery means As such, it may be possible to perform at least some significant significant exhaust heat recovery. Further, like the exhaust heat recovery device 360, the exhaust gas can be supplied without being affected by the operating conditions of the engine 200 or the vehicle 10 as the internal combustion engine (may be excluded when the internal combustion engine is stopped). By providing at least one exhaust heat recovery means, the exhaust is somewhat subject to exhaust heat recovery. Moreover, compared with the case where these are arrange | positioned mutually in series, the flow-path resistance in the supply path | route of a cooling water becomes comparatively small easily, and it becomes possible to circulate and supply cooling water efficiently.

  Here, in particular, the flow rate of the cooling water corresponding to each exhaust heat recovery means is often different in required amount or required amount depending on various operating conditions of the engine 200 or the vehicle 10. In this case, in the configuration in which the plurality of exhaust heat recovery means are only arranged in parallel with each other, physically, mechanically, or electrically, for example, via the cooling water discharge amount control in various pumps, In addition to increasing or decreasing the flow rate of the cooling water in the entire supply path (that is, the supply amount of the cooling water), there is hardly any means for controlling the flow rate corresponding to each of them. Therefore, when a change in the flow rate of the cooling water is required in one exhaust heat recovery means, it is difficult to avoid a change in the flow rate of the cooling water corresponding to the other exhaust heat recovery means arranged in parallel.

  On the other hand, when the change in the flow rate of the cooling water corresponding to the other exhaust heat recovery unit occurs with the change in the flow rate of the cooling water in the one exhaust heat recovery unit, the situation in the other exhaust heat recovery unit is originally considered. Therefore, in the other exhaust heat recovery means, a problem that cannot be overlooked in practice, such as an excessive amount of cooling water being supplied or a flow rate of the cooling water being insufficient, is likely to occur. Therefore, as one of the more realistic choices, it may be necessary to determine the flow rate of the cooling water in the entire supply path according to the circumstances of the exhaust heat recovery means having a higher degree of urgency. However, when the flow rate of the cooling water increases in the entire supply path, in some cases, excessive cooling of the wall of the internal combustion engine causes a cooling loss (hereinafter referred to as “cold loss” as appropriate). Deterioration of fuel consumption and emission can occur. That is, even if a plurality of exhaust heat recovery means are simply arranged in series with each other in parallel with the heater core, the heat supply to the heater core itself can be suitably performed, but the engine warm-up or cooling water utilization efficiency, etc. It may be difficult to eliminate the adverse effects on

  In that regard, the vehicle 10 according to the present embodiment includes a flow rate control valve 380 that is an example of the “flow rate changing unit” according to the present invention, and the flow rate ratio of the cooling water between the plurality of exhaust heat recovery units is The exhaust heat recovery system 300 can be changed so as to be optimally operated. The operation state of the flow rate control valve 380 is controlled by the flow rate control process.

<Details of flow rate control process>
The ECU 100 controls the open / closed state of the flow rate control valve 380 by executing the flow rate control process, thereby realizing efficient and effective recovery and use of exhaust heat. Here, the details of the flow rate control process will be described with reference to FIG. FIG. 3 is a flowchart of the flow rate ratio control process.

  In FIG. 3, the ECU 100 determines whether or not the cooling water temperature Thw detected by the water temperature sensor 217 is lower than a preset first threshold thw1 (step S101).

  Such an operation of the ECU 100 is an example of “specification” in the present invention relating to the cooling water temperature. Here, “specific” according to the present invention refers to, for example, detecting directly or indirectly as a physical numerical value or an electric signal or the like corresponding to the physical numerical value via some detection means, or storing appropriate memory in advance. From the map stored in the means etc., select the corresponding numerical value, or estimate through such selection, the detected physical numerical value or electrical signal or the selected or estimated numerical value, etc. It is a broad concept encompassing derivation or estimation in accordance with an algorithm, a calculation formula, or the like, or simply acquiring a value detected, selected, estimated or derived as an electrical signal or the like. Therefore, the aspect in which the ECU 100 acquires the cooling water temperature Thw is not limited to that in the present embodiment.

  Here, the first threshold thw1 is set to a value that can define whether or not the engine 200 has been warmed up, and is set to 40 ° C. in the present embodiment. When the coolant temperature Thw is less than the first threshold thw1 (step S101: YES), the ECU 100 selects and executes the low water temperature mode as the operation mode of the flow rate control valve 380, and changes the operation state of the flow rate control valve 380. The operation state corresponding to the low water temperature mode is controlled (step S102). The low water temperature mode will be described later.

  On the other hand, when the cooling water temperature Thw is equal to or higher than the first threshold thw1 (step S101: NO), the ECU 100 determines whether the cooling water temperature Thw detected by the water temperature sensor 217 is lower than a preset second threshold thw2. It is determined whether or not (step S103). Here, the second threshold thw2 is set to a value that can define whether or not the cooling water is in a high temperature state, and is set to 80 ° C. in the present embodiment. When the cooling water temperature Thw is lower than the second threshold thw2 (step S103: YES), the ECU 100 selects and executes the intermediate water temperature mode as the operation mode of the flow rate control valve 380, and changes the operation state of the flow rate control valve 380. It controls to the operation state corresponding to the said middle water temperature mode (step S104). The medium water temperature mode will be described later.

  On the other hand, when the cooling water temperature Thw is equal to or higher than the second threshold thw2 (step S103: NO), the ECU 100 determines whether the cooling water temperature Thw detected by the water temperature sensor 217 is lower than a preset third threshold thw3. It is determined whether or not (step S105). Here, the third threshold thw3 is set to a value that can define whether or not the cooling water is in an ultra-high temperature state, and is set to 95 ° C. in the present embodiment. When the cooling water temperature Thw is less than the third threshold thw3 (step S105: YES), the ECU 100 selects and executes the high water temperature mode as the operation mode of the flow rate control valve 380, and changes the operation state of the flow rate control valve 380. It controls to the operation state corresponding to the said high water temperature mode (step S106). The high water temperature mode will be described later.

  On the other hand, when the cooling water temperature Thw is equal to or higher than the third threshold thw3 (step S105: NO), the ECU 100 selects and executes the ultra-high water temperature mode as the operation mode of the flow rate control valve 380, and sets the flow rate control valve 380. The operation state is controlled to an operation state corresponding to the ultra high water temperature mode (step S107). The super high water temperature mode will be described later. Here, supplementally, as a situation where the coolant temperature Thw is likely to be equal to or higher than the third threshold thw3, there is a case where the engine 200 is mainly in a high load state. Therefore, the process according to step S107 can be replaced by determining whether or not the engine 200 is in a high load state. Of course, the cooling water temperature Thw is not necessarily equal to or higher than thw3 in a high load state, but in other words, in this case, the cooling water temperature Thw is prevented from being equal to or higher than thw3. Therefore, the ECU 100 determines whether or not the engine 200 is in a high load state based on the intake air amount, the accelerator opening, the throttle opening, or a load factor that can be calculated from the intake air amount, the fact that it is in the high load state. If it is determined, the super high water temperature mode may be executed.

  In the process according to step S102, S104, S106 or S107, when the operation state of the flow rate control valve 380 is controlled to an operation state corresponding to any of the operation modes described above, the ECU 100 returns the process to step S101, Repeat a series of processes. The flow rate ratio control process is executed as described above.

  Here, with reference to FIG. 4, details of various operation modes selected and executed in the flow ratio control process will be described. FIG. 4 is a table showing the flow rate ratio and flow rate corresponding to each operation mode.

  In FIG. 4, in the low water temperature mode, the flow rate ratio between the EGR cooler 370 and the exhaust heat recovery device 360 is set to “0: 100”. That is, all of the cooling water (hereinafter referred to as “reference cooling water” as appropriate) led to the flow rate control valve 380 in the main circulation path 310d (ie, 100%, hereinafter referred to as “reference flow rate” as appropriate). Is supplied to the exhaust heat recovery device 360. In FIG. 4, it is assumed that the reference flow rate is 6 L (liter) / min uniformly for each operation mode.

  Here, the situation where the low water temperature mode is executed is a situation where the engine 200 can be judged to be in an unwarmed state, that is, a situation where the combustibility is judged to be relatively poor. Therefore, the ECU 100 closes the EGR valve 219 at the timing when the low water temperature mode should be executed. In the state where the EGR valve 219 is closed, the EGR gas does not recirculate through the EGR pipe 218, so that the necessity of cooling the EGR gas by the EGR cooler 370 also does not occur. On the other hand, considering that the engine 200 is in an unwarmed state, the engine 200 should be warmed up early, and the cooling water needs to be heated as quickly as possible.

  Therefore, the ECU 100 controls the flow rate control valve so that all the reference cooling water is supplied to the exhaust heat recovery device 360 in order to raise the temperature of the cooling water by exchanging heat between the exhaust heat recovery device 360 and the cooling water. 380 is controlled. As a result, the flow rate of the cooling water in the exhaust heat recovery device 360 is controlled to 6 L / min which is equal to the reference flow rate. In this way, in the low water temperature mode, the flow rate control valve 380 supplies heat to the cooling water with the maximum efficiency that can be substantially realized, and is used to warm up the engine 200. That is, the engine 200 is warmed up preferentially.

  As far as the flow rate ratio is concerned, if the flow rate ratio corresponding to the exhaust heat recovery device 360 is increased, the flow rate ratio corresponding to the EGR cooler 370 is uniquely reduced. As described above, since the necessity of operating the EGR cooler 370 is low when the cooling water temperature Thw is low, a sufficient effect in practice can be obtained only by changing the flow rate ratio, but as a more effective aspect, With the setting of the flow rate ratio, the supply amount of the cooling water may be changed by the control of the electric W / P 320. That is, when the required flow rate of the cooling water as the entire supply path is small, the supply amount is controlled before or after the control of the flow rate ratio, and for example, the flow rate corresponding to the exhaust heat recovery device 360 is increased. However, the flow rate of the cooling water in the entire supply path may be suppressed as compared with, for example, the case where the cooling water temperature Thw is not low (that is, at least when the unwarmed state can be considered to have been removed).

  In FIG. 4, in the intermediate water temperature mode, the flow rate ratio between the EGR cooler 370 and the exhaust heat recovery device 360 is “50:50”, that is, the reference cooling water is equally divided and corresponds to 50% of the reference flow rate. Cooling water is supplied to the exhaust heat recovery device 360 and the EGR cooler 370. That is, 3 L / min of cooling water is supplied. Supplementally, in the situation where the medium water temperature mode is executed, it can be determined that the engine 200 is warmed up to such an extent that combustion of the engine 200 does not become unstable even when the EGR device is operated. Therefore, the ECU 100 opens the EGR valve 219 at the timing when the middle water temperature mode should be executed. In the state where the EGR valve 219 is opened, the EGR gas recirculates to the intake system via the EGR pipe 218, so that it may be necessary to cool the EGR gas by the EGR cooler 370. On the other hand, the engine 200 is not necessarily sufficiently warmed up, and still has room for warming up. Therefore, warm-up of engine 200 is continued. Therefore, by controlling the flow rate control valve 380 so that the flow rate ratio becomes “50:50”, warm-up of the engine 200 and cooling of the EGR gas are compatible in the intermediate water temperature mode.

  In FIG. 4, in the high water temperature mode, the flow rate ratio between the EGR cooler 370 and the exhaust heat recovery device 360 is “100: 0”, that is, all the reference cooling water is supplied to the EGR cooler 370. That is, the flow rate of the cooling water in the EGR cooler 370 is 6 L / min equal to the reference flow rate. Supplementally, the situation in which the high water temperature mode is executed is a situation in which it can be determined that the engine 200 has been warmed up. Therefore, the ECU 100 opens the EGR valve 219 more greatly at the timing when the high water temperature mode is to be executed, and actively recirculates the EGR gas to the intake system. Therefore, the necessity for cooling the EGR gas is higher than in the two types of modes described above.

  On the other hand, when the engine 200 is warmed up, it is not necessary to warm up the engine 200 by applying exhaust heat to the cooling water. For example, the engine 200 is used as a heat source for the heater core 350 when the engine 200 is stopped. Except for the situation described above, the exhaust heat recovery device 360 is substantially unnecessary. That is, in this situation, there is basically no need to supply cooling water to the exhaust heat recovery unit 360. However, unlike the EGR device, the exhaust heat recovery unit 360 does not have the concept of operation and non-operation, and therefore the exhaust heat recovery unit 360 continues to recover exhaust heat regardless of the cooling water temperature Thw. Here, in particular, when the supply of the cooling water to the exhaust heat recovery device 360 is continued, the cooling water is supplied with excess heat from the exhaust heat recovery device 360. At the timing when the high water temperature mode is executed, the ECU 100 causes the radiator 340 to appropriately dissipate the cooling water while supplying the cooling water, so that the excess heat supplied from the exhaust heat recovery device 360 is eventually passed through the radiator 340 to the outside as it is. It will only be released. Therefore, in the high water temperature mode, it is better not to supply the cooling water to the exhaust heat recovery device 360, and all the reference cooling water is supplied to the EGR cooler 370 so that the recovered heat can be used efficiently. It becomes.

  As far as the flow rate ratio is concerned, if the flow rate ratio corresponding to the EGR cooler 370 is increased, the flow rate ratio corresponding to the exhaust heat recovery device 360 is uniquely lowered. Thus, when the cooling water temperature Thw is high, the necessity of heat exchange between the exhaust heat recovery device 360 and the cooling water is reduced as described above, and a practically sufficient effect can be obtained only by changing the flow rate ratio. However, as a more effective aspect, the supply amount of the cooling water may be changed by the control of the electric W / P 320 in accordance with the setting of the flow rate ratio. That is, if the required flow rate of the cooling water for the entire supply path is small, the supply amount is controlled immediately before the flow rate ratio control, for example, while increasing the flow rate corresponding to the EGR cooler 370. The overall flow rate may be suppressed.

  In FIG. 4, in the super high water temperature mode, the flow rate ratio between the EGR cooler 370 and the exhaust heat recovery device 360 is “0: 100”, that is, all of the reference cooling water (ie, as in the low water temperature mode) Cooling water having a flow rate of 6 L / min is supplied to the exhaust heat recovery device 360.

  When the load state of the internal combustion engine corresponds to a high load state typified by, for example, transient operation, the exhaust heat recovery means recovers more heat than when it is not in a high load state, and is set in advance. There is a possibility that the heat capacity will be exceeded. In this case, the cooling water remaining inside the exhaust heat recovery device 360 may boil and cause some adverse effects. On the other hand, the EGR cooler 370 similarly cools the exhaust gas. However, the EGR device is provided with an EGR valve 219 for controlling the flow rate of the EGR gas, and the operating state of the EGR device can be controlled relatively easily. Therefore, in such a high load state, the exhaust heat recovery device 360 is more likely to cause a practical disadvantage due to excessively high cooling water. Therefore, when the ultra high water temperature mode is executed, the flow rate ratio and / or flow rate of the cooling water is set so that the exhaust heat recovery device 360 is cooled at least in preference to the EGR cooler 370.

  Note that, in this case, the cooling water supply to the exhaust heat recovery device 360 is given priority in this case. Ideally, the cooling water supply to the EGR cooler 370 is such an exhaust heat recovery device. It may be better to continue regardless of the circumstances of 360. In preparation for such a case, the ECU 100 increases the flow rate of the cooling water corresponding to the exhaust heat recovery device 360 by increasing the flow rate of the cooling water supply path as a whole via the electric W / P 320, and the EGR. An optimal amount of cooling water may be supplied to the cooler 370.

  Further, the determination as to whether or not the engine 200 is in a high load state in which the super high water temperature mode should be executed may not be made based only on the cooling water temperature Thw. For example, the ECU 100 determines the load state of the engine 200 that is an internal combustion engine (for example, alternatively defined by torque, intake air amount, accelerator opening, etc.) as part of the “operating condition” according to the present invention. , By acquiring electrical signals corresponding to various indicators such as intake air amount, accelerator opening or throttle opening obtained from an air flow meter, accelerator position sensor or throttle opening sensor, etc. Based on the determination of whether or not it is satisfied, it may be determined whether or not the vehicle is in a high load state separately from or in addition to the determination based on the cooling water temperature Thw. In this case, it is possible to detect such a situation before the cooling water temperature Thw actually rises. In other words, it is possible to actively control the cooling water temperature Thw.

  As described above, according to the flow rate control process according to the present embodiment, the flow rate ratio between the EGR cooler 370 and the exhaust heat recovery device 360 is basically controlled according to the cooling water temperature Thw. Here, in particular, in the case where there is no flow rate change means corresponding to the flow rate control valve 380 in the present embodiment, the flow rate ratio can only be a fixed value that is adapted in advance. Here, for example, when the fixed flow rate ratio is “50:50 (ie, 1: 1)”, for example, if the low water temperature mode described above is taken as an example, a sufficient amount for the exhaust heat recovery device 360 is obtained. In order to supply cooling water (for example, 6 L / min), the flow rate of cooling water in the EGR cooler 370 inevitably has to be approximately the same. In this case, the flow rate of the reference cooling water (that is, the reference flow rate) is 12 L / min, the supply amount of the cooling water is clearly excessive as compared with the present embodiment, the cooling loss of the cooling water increases, and the engine 200 As a result, the wall is excessively cooled, and warm-up is hindered. Alternatively, fuel consumption may be deteriorated by unnecessarily increasing the amount of cooling water supplied.

  On the other hand, according to this embodiment, since the flow rate ratio is variable, the flow rate of the cooling water corresponding to one exhaust heat recovery means is changed while maintaining the flow rate of the cooling water in the entire cooling water supply path. It becomes possible to make it. Alternatively, by changing the flow rate ratio while changing the cooling water supply amount, for example, while maintaining the flow rate of the cooling water corresponding to one exhaust heat recovery means, the flow rate corresponding to another exhaust heat recovery means Can be increased or decreased. In other words, it becomes possible to effectively and effectively control the flow rate of the cooling water supplied to the individual exhaust heat recovery means. Therefore, efficient and effective recovery and use of exhaust heat can be realized without causing such an increase in cooling loss and without causing deterioration of fuel consumption.

  The kinematic viscosity of the cooling water changes according to the cooling water temperature, and the kinematic viscosity tends to increase as the cooling water temperature decreases. Therefore, qualitatively, the cooling water becomes difficult to flow as the cooling water temperature is low, and the pressure loss (hereinafter referred to as “pressure loss” as appropriate) increases. When the cooling water temperature changes, the expected flow rate may not be obtained. In order to deal with such a problem, for example, the reference flow rate of the cooling water itself in various operation modes according to the present embodiment may be variable according to the operating conditions including the cooling water temperature. Alternatively or additionally, the flow rate ratio may be determined or corrected taking into account the kinematic viscosity of such cooling water.

In the present embodiment, the cooling water temperature Thw is divided into four regions associated with the operation mode of the flow rate control valve 380, and the operation mode is changed depending on which temperature region the cooling water temperature Thw belongs to. However, “when the temperature of the cooling water is low” or “when the temperature of the cooling water is high” according to the present invention is not necessarily defined by such a fixed stepwise index. For example, the determination may be made flexibly by using an index that is variable according to various operating conditions of the internal combustion engine at that time, environmental conditions in which the vehicle 10 is placed, and the like. Furthermore, the operation state of the flow ratio control valve 380 is not limited to the four types of operation modes according to the present embodiment, and may be changed more continuously.
Second Embodiment
In the first embodiment described above, the operating state of the flow ratio control valve 380 is controlled using the flow ratio as a parameter. On the other hand, the electric W / P 320 provided in the exhaust heat recovery system 300 is controlled by the ECU 100 and the drive unit so that the discharge amount of the cooling water or the motor rotation speed defining the discharge amount is independent of the rotation of the crankshaft 205 of the engine 200. Can be done. Therefore, when performing various operation modes corresponding to each cooling water temperature range, not only the flow rate ratio described in the first embodiment, but also the supply amount of cooling water circulated and supplied into the cooling water circulation path 310 is set to the flow rate ratio. It can be changed accordingly.

  Here, with reference to FIG. 5, details of various operation modes in the flow ratio control process according to the second embodiment of the present invention will be described. FIG. 5 is a table showing the flow rate ratio and flow rate corresponding to each operation mode. In the figure, the same reference numerals are given to the same portions as those in FIG. 4, and the description thereof will be omitted as appropriate.

  In FIG. 5, the flow rate ratio between the EGR cooler 370 and the exhaust heat recovery device 360 in each operation mode is the same as that in the first embodiment except for the super high water temperature mode. Here, in the low water temperature mode, the flow rate ratio between the EGR cooler 370 and the exhaust heat recovery device 360 is “0: 100” as in the first embodiment, but the reference flow rate is reduced to 5 L / min. Has been. That is, when executing the low water temperature mode, the ECU 100 controls the electric W / P 320 as efficiently as possible as long as a flow rate sufficient to warm up the engine 200 is obtained, and the flow rate of the cooling water is appropriately adjusted. change. That is, in this case, it is sufficient that the flow rate of 5 L / min is substantially secured, and the power resource required to drive the electric W / P 320 is saved as compared with the first embodiment.

  The same applies to the high water temperature mode. Assuming that the flow rate to be supplied to the EGR cooler 370 is 5 L / min, not only the flow rate ratio but also the discharge amount of the electric W / P 320 is changed. In the middle water temperature mode, the reference flow rate is controlled to 6 L / min as in the first embodiment.

  Here, when the super high water temperature mode is executed, in the first embodiment, the flow rate ratio between the EGR cooler 370 and the exhaust heat recovery device 360 is “0: 100 ". However, the EGR cooler 370 originally needs to be supplied with cooling water. In view of this point, the ECU 100 increases the reference flow rate, and the exhaust heat recovery device 360 has 6 L / min of cooling water as in the first embodiment. The cooling water of 5 L / min is also supplied to the EGR cooler 370. As a result, the flow rate ratio is “55:45”.

  As described above, according to the second embodiment, the cooling water corresponding to the EGR cooler 370 and the exhaust heat recovery device 360 is controlled not only by the flow rate ratio but also by variably controlling the cooling water discharge amount by the electric W / P 320. It is possible to substantially freely control the flow rate. Also, as shown in the low water temperature mode and high water temperature mode, it is possible to suppress the overall cooling water flow rate, and as shown in the super high water temperature mode, supply the required amount of cooling water to the necessary locations. It is also possible to increase the amount of cooling water supplied to the entire cooling water circulation path 310. That is, according to the second embodiment, exhaust heat can be recovered and used more efficiently and effectively.

When the flow rate of the cooling water itself is made variable in this way, the influence of the kinematic viscosity of the cooling water according to the cooling water temperature Thw, that is, the lower the cooling water temperature Thw, the higher the kinematic viscosity of the cooling water and the pressure loss. The increasing problem can be dealt with favorably. That is, when such an increase in pressure loss is expected, the flow rate of the cooling water is not affected by the pressure loss by correcting the overall flow rate of the cooling water so that the increase amount of the pressure loss can be canceled in advance. Can be optimized.
<Third Embodiment>
On the other hand, the change in pressure loss of the cooling water circulation path 310 when the cooling water is circulated and supplied does not depend only on the kinematic viscosity of the cooling water as described above, but various types as shown in the first and second embodiments. It can also occur when the flow ratio changes through the embodiment. The change in the pressure loss leads to a change in the flow rate of the cooling water. For example, the change in the pressure loss caused by the change in the flow rate ratio may cause a sudden change in the cooling water temperature Thw, which may affect the control of the flow rate ratio. is there. Further, there is a concern that knocking may occur due to such a rapid change in the cooling water temperature Thw.

  As a third embodiment of the present invention that can deal with such a problem, a change may be made to the execution mode of each operation mode in the flow rate ratio control processing according to each of the above-described embodiments. That is, when executing each operation mode in steps S102, S104, S106, and S107, the ECU 100 continuously monitors the output of the water temperature sensor 217, and prevents the rapid change in the cooling water temperature Thw from occurring. You may control the operation state of 380 or electric W / P320 or both. At this time, the following process (1) or (2) may be performed as a technique for suppressing the sudden change in the cooling water temperature Thw.

(1) Sudden change suppression control based on time differential value of cooling water temperature Thw (2) Sudden change suppression control based on difference of cooling water temperature Thw before and after changing the flow rate ratio When the control corresponding to the above (1) is performed, the ECU 100 The flow rate ratio is calculated so that the time change amount of the cooling water temperature Thw is calculated as the differential value, and the time change amount is equal to or less than a predetermined value set in advance so that it can be determined that the cooling water temperature Thw has not suddenly changed. Control the control valve 380 or the electric W / P 320 or both. When the control corresponding to (2) is performed, the ECU 100 controls the flow rate ratio control valve 380 so that the difference in the cooling water temperature Thw before and after the execution of the process related to the step corresponding to each operation mode is equal to or less than a predetermined value. Alternatively, the electric W / P 320 is controlled.

  By adopting these various aspects, a sudden change in the cooling water temperature Thw is suppressed, so that control problems and knocking are prevented, and the benefits according to the various embodiments described above are more remarkably enjoyed. Is possible.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and an exhaust heat recovery apparatus with such a change. Is also included in the technical scope of the present invention.

1 is a schematic configuration diagram conceptually illustrating a configuration of a vehicle according to a first embodiment of the present invention. It is a schematic diagram of the engine in the vehicle of FIG. 2 is a flowchart of a flow ratio control process executed by an ECU in the vehicle of FIG. It is a table | surface explaining the various operation modes of the flow ratio control valve selected and performed in the process of FIG. It is a table | surface explaining various operation modes of the flow ratio control valve which concerns on 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Vehicle, 100 ... ECU, 200 ... Engine, 300 ... Exhaust heat recovery system, 310 ... Cooling water circulation flow path, 320 ... Electric W / P, 330 ... Thermostat, 340 ... Radiator, 350 ... Heater core, 360 ... Exhaust heat recovery 370 ... EGR cooler, 380 ... Flow ratio control valve.

Claims (7)

An exhaust heat recovery device that recovers exhaust heat related to exhaust of an internal combustion engine in a vehicle including an internal combustion engine and a heater core as a cooling water supply target,
A plurality of exhaust heat recovery means capable of recovering the exhaust heat disposed in parallel to each other in series with the heater core in the cooling water supply path as part of the supply target;
An exhaust heat recovery apparatus comprising: a flow rate ratio changing means capable of changing a flow rate ratio of the cooling water between the plurality of exhaust heat recovery means. Specifying means for specifying an operating condition of the internal combustion engine including at least a temperature of the cooling water;
Setting means for setting at least one of the flow rate and the flow rate of the cooling water to be supplied to at least some of the plurality of exhaust heat recovery means based on the specified operating condition;
The exhaust heat recovery apparatus according to claim 1, further comprising: a first control unit that controls the flow rate ratio changing unit according to at least one of the set values. Supply means capable of supplying the cooling water to the supply path independently of engine rotation of the internal combustion engine;
The exhaust heat recovery apparatus according to claim 2, further comprising: a second control unit that controls the supply unit in accordance with at least one of the set values. The plurality of exhaust heat recovery means includes an EGR cooler capable of cooling EGR gas recirculated to the intake system of the internal combustion engine, and an exhaust heat recovery device capable of heating the cooling water by the recovered exhaust heat. The exhaust heat recovery apparatus according to claim 2 or 3, characterized in that The setting means sets the flow rate ratio corresponding to at least the exhaust heat recovery device according to the temperature of the specified cooling water so as to increase when the temperature of the cooling water is low. The exhaust heat recovery apparatus according to claim 4. The setting means sets the flow rate ratio corresponding to at least the EGR cooler according to the temperature of the specified cooling water so as to increase when the temperature of the cooling water is high. The exhaust heat recovery apparatus according to 4 or 5. The specifying means specifies a load state of the internal combustion engine as a part of the operating condition,
The setting means sets the at least one so that the exhaust heat recovery device is cooled at least in preference to the EGR cooler when the specified load state corresponds to a predetermined high load state. The exhaust heat recovery apparatus according to any one of claims 4 to 6, characterized in that

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