JP2018025106A - Heat exchange system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchange system capable of efficiently warming up an engine.SOLUTION: A heat exchange system 1 includes: an engine 10; a heat exchanger 30 provided in an exhaust passage (third passage 27) through which exhaust gas of the engine 10 flows, and exchanging heat between the exhaust gas and cooling water; a first cooling water flow passage 41 through which the cooling water flows from the heat exchanger 30 to the engine 10; a second cooling water flow passage 42 through which the cooling water flows from the engine 10 to the heat exchanger 30; and a first heat accumulating section 51 and a second heat accumulating section 52 provided in the first cooling water flow passage 41 and the second cooling water flow passage 42, and accumulating heat of the cooling water.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heat exchange system having an engine and a heat exchanger.

  The vehicle includes a heat exchanger that is provided in an exhaust passage of the engine and serves as a recovery unit that recovers exhaust heat by exchanging heat between the exhaust gas of the engine and the refrigerant. For example, a heat exchanger heats cooling water by exchanging heat between engine cooling water, which is an example of a refrigerant, and exhaust gas. The heated cooling water is used, for example, to promote engine warm-up.

JP 2007-247555 A

  By the way, when the engine is warmed up by the cooling water heated by the heat exchanger, it takes a long time to warm the engine to a predetermined temperature. In particular, when the flow path between the engine and the heat exchanger is long, the cooling water heated by the heat exchanger dissipates heat before reaching the engine, and the engine cannot be warmed up efficiently.

  Accordingly, the present invention has been made in view of these points, and an object thereof is to provide a heat exchange system that can efficiently warm up an engine.

In one aspect of the present invention, an engine, a heat exchanger provided in an exhaust passage through which exhaust gas of the engine flows, and exchanging heat between the exhaust gas and the refrigerant, and the refrigerant from the heat exchanger to the engine A first flow path through which the refrigerant flows, a second flow path through which the refrigerant flows from the engine to the heat exchanger, and a heat storage section that is provided in the first flow path and the second flow path and stores heat of the refrigerant. A heat exchange system is provided.
According to such a heat exchange system, the heat storage unit is provided in the first flow path and the second flow path, thereby suppressing the heat of the cooling water from being radiated. Thereby, at the time of engine warm-up, the engine can be efficiently warmed up by the refrigerant stored in the heat storage section. As a result, the engine can be warmed up early.

  The heat exchange system includes a first valve that is provided on the engine side in the first flow path and the second flow path, and opens or closes the flow path, and the first flow path and the second flow path. And a second valve that opens or closes the flow path, and the heat storage section is provided between the first valve and the second valve. Also good.

  The heat exchange system closes the flow path to the first valve and the second valve when the engine is stopped, and opens the flow path to the first valve and the second valve when the engine is warmed up. It is good also as providing a control part.

  The heat exchange system further includes: a first temperature detection sensor that detects the temperature of the refrigerant in the first flow path; and a second temperature detection sensor that detects the temperature of the refrigerant in the second flow path. The control unit operates the first valve and the second valve when the engine is warmed up, and supplies the refrigerant having the higher temperature of the refrigerant in the first flow path and the second flow path. It is good also as flowing to the engine side and flowing the refrigerant | coolant with a low temperature to the said heat exchanger.

  Further, the heat exchange system may be configured such that an outside air flow path through which the outside air flows via the heat exchanger and a target to be heat exchanged with the refrigerant in the heat exchanger are any of the exhaust gas and the outside air. A switching unit for switching, and the first flow path may flow the refrigerant cooled by exchanging heat with the outside air in the heat exchanger to the engine.

  According to the present invention, it is possible to provide a heat exchange system capable of efficiently warming up the engine.

It is a mimetic diagram showing an example of composition of heat exchange system 1 concerning one embodiment. It is a mimetic diagram showing heat exchange system 1 at the time of cooling engine 10 with cooling water. 1 is a schematic diagram showing a heat exchange system 1 when an engine 10 is stopped. It is a mimetic diagram showing heat exchange system 1 at the time of warming up engine 10 with cooling water.

<Configuration of heat exchange system>
The configuration of the heat exchange system 1 according to one embodiment of the present invention will be described with reference to FIGS.

  Drawing 1 is a mimetic diagram showing an example of the composition of heat exchange system 1 concerning one embodiment. FIG. 2 is a schematic diagram showing the heat exchange system 1 when the engine 10 is cooled with cooling water. FIG. 3 is a schematic diagram showing the heat exchange system 1 when the engine 10 is stopped. FIG. 4 is a schematic diagram showing the heat exchange system 1 when the engine 10 is warmed up with cooling water. 1 to 4, the flow of exhaust gas is indicated by wavy arrows, and the flow of outside air is indicated by dashed-dotted arrows.

  Here, the heat exchange system 1 is mounted on a large vehicle such as a truck. As shown in FIG. 1 and the like, the heat exchange system 1 includes an engine 10, a first passage 20, an aftertreatment device 23, a second passage 25, a third passage 27, a heat exchanger 30, and cooling water. It has a passage 40 and an ECU 80. The heat exchange system 1 is a system that heats or cools the refrigerant by exchanging heat between the exhaust gas or outside air of the engine 10 and the refrigerant.

  The engine 10 is an engine including a plurality of cylinders, and is a diesel engine in the present embodiment, but can also be applied to a gasoline engine. The engine 10 generates power by burning and expanding a mixture of fuel and intake air (air) in a cylinder. The intake air is drawn into the cylinders of the engine 10 through an intake passage (not shown). Further, the engine 10 exhausts the exhaust gas after combustion.

  The first passage 20 is a passage through which exhaust gas discharged from the engine 10 flows. The 1st channel | path 20 is comprised, for example with the pipe | tube. One end of the first passage 20 in the longitudinal direction is connected to the engine 10. The other end in the longitudinal direction of the first passage 20 is a connection portion connected to the second passage 25 and the third passage 27 via the switching valve 29. In the present embodiment, the first passage 20, the second passage 25, and the third passage 27 constitute an exhaust gas exhaust passage.

The post-processing device 23 is provided in the first passage 20 and is a device that purifies exhaust gas. Here, the post-processing device 23 has a DPF (Diesel Particulate Filter) and an SCR (Selective Catalytic Reduction). The DPF collects PM in the exhaust gas. The SCR selectively reduces and purifies NO _x in the exhaust gas using ammonia (NH ₃ ) generated by hydrolysis from urea water as a reducing agent.

  The second passage 25 is a passage through which exhaust gas released to the atmosphere flows. One end in the longitudinal direction of the second passage 25 is connected to the other end in the longitudinal direction of the first passage 20 via the switching valve 29. The diameter of the switching valve 29 is changed inside, and the second passage 25 is connected to a portion of the switching valve 29 having a larger diameter. The switching valve 29 has a T-shaped T-shaped hole 29a inside and is rotatably provided. The other end of the second passage 25 in the longitudinal direction is provided with an opening through which the exhaust gas is released to the atmosphere. The inner diameter of the tubular second passage 25 is larger than the inner diameters of the first passage 20 and the third passage 27.

  The third passage 27 is a passage through which exhaust gas released to the atmosphere flows. One end in the longitudinal direction of the third passage 27 is connected to the other end in the longitudinal direction of the first passage 20 via the switching valve 29. The other end of the third passage 27 in the longitudinal direction is provided with an opening through which exhaust gas is released to the atmosphere. A heat exchanger 30 is provided in the third passage 27. Note that the third passage 27 also has a function of an outside air flow path in which outside air that has flowed in from the open port flows via the heat exchanger 30.

  In the present embodiment, by controlling the switching valve 29, the exhaust gas flowing through the first passage 20 is released to the atmosphere from either the second passage 25 or the third passage 27. For example, when the engine 10 is warmed up, as shown in FIG. 4, the exhaust gas flows through the third passage 27, exchanges heat with the cooling water of the engine 10 in the heat exchanger 30, and then is released to the atmosphere from the opening. . On the other hand, after the warm-up of the engine 10 is finished, as shown in FIG. 2, the exhaust gas flows through the second passage 25 and is released to the atmosphere from the opening. The opening of the second passage 25 may be provided on the rear side of the vehicle, and the opening of the third passage 27 may be provided on the front side of the vehicle.

  In addition, when the second passage 25 and the third passage 27 are communicated with the first passage 20, the exhaust gas flowing through the first passage 20 has an inner diameter of the second passage 25 that is larger than an inner diameter of the third passage 27. Therefore, it flows through the second passage 25 as shown in FIG. In the present embodiment, when the exhaust gas flows into the second passage 25, outside air that flows in from the opening of the third passage 27 flows into the second passage 25 from the third passage 27. This is because the following phenomenon using the action of the jet flow involving the surrounding fluid occurs. That is, since the diameter of the path of the switching valve 29 is larger than the diameter of the first passage 20, the exhaust gas emitted from the first passage 20 becomes a jet at a portion where the diameter of the path changes in cross section, and the diameter of the path By connecting the third passage 27 to the portion where the air gap becomes larger, the outside air of the third passage 27 is drawn. The outside air that has flowed into the second passage 25 is mixed with the exhaust gas. Here, since the temperature of the outside air is lower than the temperature of the exhaust gas, the temperature of the exhaust gas is lowered by mixing the outside air with the exhaust gas.

  The heat exchanger 30 is provided in the third passage 27 and exchanges heat between the exhaust gas and the refrigerant. Here, the refrigerant is cooling water of the engine 10 that flows through the cooling water passage 40. Since the temperature of the cooling water is lower than the temperature of the exhaust gas, the cooling water is heated by exchanging heat with the exhaust gas.

  Further, the heat exchanger 30 exchanges heat between the outside air and the cooling water flowing through the cooling water passage 40 when the outside air flowing in from the opening of the third passage 27 flows through the third passage 27. Since the temperature of the cooling water is higher than the temperature of the outside air, the cooling water is cooled by exchanging heat with the outside air. That is, the heat exchanger 30 functions as a sub radiator.

  As described above, in the present embodiment, the switching valve 29 functions as a switching unit that switches an object to be heat exchanged with the cooling water in the heat exchanger 30 to the exhaust gas or the outside air. For example, when the switching valve 29 does not communicate the second passage 25 with the first passage 20, the exhaust gas flows from the first passage 20 to the third passage 27 as shown in FIG. Heat is exchanged with cooling water in the vessel 30. On the other hand, when the switching valve 29 communicates the second passage 25 and the third passage 27 with the first passage 20, the exhaust gas flows from the first passage 20 to the third passage as shown in FIG. 2. It flows to 27. At this time, outside air flows from the third passage 27 into the second passage 25.

  The cooling water passage 40 is a passage through which the cooling water of the engine 10 that is a refrigerant flows. The cooling water has a function of cooling the inside of the engine 10. The cooling water passage 40 is provided so that the cooling water circulates between the engine 10 and the heat exchanger 30. When the engine 10 is warmed up, the cooling water heated by exchanging heat with the exhaust gas in the heat exchanger 30 is sent to the engine 10. The cooling water passage 40 includes a first cooling water channel 41, a second cooling water channel 42, a first valve 45, a second valve 46, a first heat storage unit 51, a second heat storage unit 52, a first temperature sensor 61, and a first temperature sensor 61. A two temperature sensor 62 is provided.

  The first cooling water channel 41 is a channel through which cooling water flows from the heat exchanger 30 to the engine 10. The first cooling water channel 41 includes channels 41a to 41c. During normal operation after the engine 10 is warmed up, as shown in FIG. 2, the cooling water cooled by exchanging heat with the outside air in the heat exchanger 30 flows in the order of the flow path 41c, the flow path 41b, and the flow path 41a. To the engine 10.

  The second cooling water channel 42 is a channel through which cooling water flows from the engine 10 to the heat exchanger 30. The second cooling water channel 42 includes channels 42a to 42c. During normal operation after the engine 10 is warmed up, as shown in FIG. 2, the cooling water that has cooled the engine 10 flows in the order of the flow path 42 a, the flow path 42 b, and the flow path 42 c to reach the heat exchanger 30.

  In the present embodiment, at the time of warming up when the engine 10 is started, as shown in FIG. 4, the cooling water heated by exchanging heat with the exhaust gas in the heat exchanger 30 is supplied to the flow path 41 c and the flow. It flows in the order of the path 42b and the flow path 41a to the engine 10. Further, the cooling water that warms the engine 10 flows in the order of the flow path 42 a, the flow path 41 b, and the flow path 42 c to reach the heat exchanger 30. In addition, the change of the path | route of a flow path is implement | achieved by operating the 1st valve 45 and the 2nd valve 46 which are switching valves which can change the direction through which cooling water flows.

  As shown in FIG. 1, the first valve 45 is provided on the engine 10 side in the first cooling water passage 41 and the second cooling water passage 42. The first valve 45 opens or closes the first cooling water channel 41 and the second cooling water channel 42, respectively. The second valve 46 is provided on the heat exchanger 30 side in the first cooling water channel 41 and the second cooling water channel 42. The second valve 46 opens or closes the first cooling water channel 41 and the second cooling water channel 42, respectively.

  For example, the first valve 45 and the second valve 46 open the first cooling water passage 41 and the second cooling water passage 42 during operation of the engine 10, and the first cooling water passage 41 and the second cooling passage 42 when the engine 10 is stopped. 2 The cooling water flow path 42 is closed. Then, when the first valve 45 and the second valve 46 open the first cooling water channel 41 and the second cooling water channel 42, the cooling water circulates through the first cooling water channel 41 and the second cooling water channel 42. . On the other hand, when the first valve 45 and the second valve 46 close the first cooling water channel 41 and the second cooling water channel 42, the cooling water does not flow.

  The first heat storage unit 51 is provided in the first cooling water channel 41 and stores heat of the cooling water. The first heat storage unit 51 is provided between the first valve 45 and the second valve 46 in the first cooling water channel 41. Here, the first heat storage unit 51 is formed by covering the piping that is the first cooling water passage 41 with a heat insulating material. For example, VIP (Vacuum Insulation Panel) which is a vacuum heat insulating material is used as the heat insulating material. A vacuum heat insulating material has a function which improves the heat insulation performance by making the circumference | surroundings of a heat insulating material into a vacuum state, and making the heat conduction by gas approach zero as much as possible.

  The second heat storage unit 52 is provided in the second cooling water channel 42 and stores heat of the cooling water. The second heat storage unit 52 is provided between the first valve 45 and the second valve 46 in the second cooling water channel 42. Here, the second heat storage section 52 is formed by covering the piping that is the second cooling water passage 42 with a heat insulating material. For example, VIP (Vacuum Insulation Panel) which is a vacuum heat insulating material is used as the heat insulating material. Note that the heat insulating material of the second heat storage unit 52 may be different from the heat insulating material of the first heat storage unit 51.

  In addition to storing the heat of the cooling water, the first heat storage unit 51 and the second heat storage unit 52 described above function to block the heat from the outside, and to dissipate the cooling water whose temperature has been increased by heat exchange. It has a function to suppress. Thereby, it can suppress that the cooling water of the 1st cooling water flow path 41 arrange | positioned near the 1st channel | path 20 receives heat from the 1st channel | path 20 into which exhaust gas flows, and temperature rises. In particular, when the engine 10 is not warmed up, the engine 10 can be effectively cooled by suppressing an increase in the temperature of the cooling water.

  The first temperature sensor 61 is provided in the first cooling water passage 41 and detects the temperature of the cooling water in the first cooling water passage 41. For example, the first temperature sensor 61 detects the temperature of the cooling water stored in the first heat storage unit 51.

  The second temperature sensor 62 is provided in the second cooling water channel 42 and detects the temperature of the cooling water in the second cooling water channel 42. For example, the second temperature sensor 62 detects the temperature of the cooling water stored in the second heat storage unit 52.

  The ECU 80 is an electronic control unit (Electric Control Unit) including a microcomputer having a CPU, a ROM, a RAM, and the like. In the present embodiment, the ECU 80 functions as a control unit that controls the operations of the first valve 45 and the second valve 46.

  As shown in FIG. 3, the ECU 80 causes the first and second valves 45 and 46 to close the first cooling water passage 41 and the second cooling water passage 42 when the engine 10 is stopped. By closing the first cooling water channel 41 and the second cooling water channel 42 in this way, the heat of the cooling water in the first cooling water channel 41 and the second cooling water channel 42 is changed to the first heat storage unit 51 and the first cooling water channel 51. 2 The heat is stored by the heat storage unit 52.

  On the other hand, the ECU 80 opens the first cooling water passage 41 and the second cooling water passage 42 in the first valve 45 and the second valve 46 when the engine 10 is warmed up. Then, the ECU 80 operates the first valve 45 and the second valve 46 when the engine 10 is warmed up, and the temperature of the coolant in the first coolant channel 41 or the second coolant channel 42 is higher. The cooling water in the flow path is caused to flow toward the engine 10, and the cooling water in the flow path having a low temperature is caused to flow into the heat exchanger 30. Specifically, the ECU 80 determines which one of the cooling water in the first cooling water passage 41 and the cooling water in the second cooling water passage 42 from the detection results of the first temperature sensor 61 and the second temperature sensor 62. Whether the temperature of the water is high is specified, and the cooling water having the higher temperature is allowed to flow to the engine 10 side.

  For example, when warming up after the engine 10 is stopped, the ECU 80 causes the cooling water in the second cooling water passage 42 having a high temperature to flow toward the engine 10 as shown in FIG. 4 and the first cooling water passage 41 having a low temperature. The cooling water is passed through the heat exchanger 30. Thereby, since the engine 10 can be warmed up by the cooling water having a high temperature, the engine 10 can be warmed up at an early stage. In particular, in the case of a large vehicle such as a truck as in the present embodiment, the cooling water flow path tends to be long, so that the effect of providing the first heat storage unit 51 and the second heat storage unit 52 is more effectively exhibited. Is done.

<Effect in this embodiment>
The heat exchange system 1 according to the above-described embodiment stores heat of cooling water in a first cooling water channel 41 and a second cooling water channel 42 that are provided between the engine 10 and the heat exchanger 30 and through which cooling water flows. A first heat storage unit 51 and a second heat storage unit 52 are provided.
In such a case, the first heat storage part 51 and the second heat storage part 52 are provided in the first cooling water flow path 41 and the second cooling water flow path 42 so that the heat of the cooling water can be suppressed from being radiated. . Thereby, when the engine 10 is warmed up, the engine 10 can be efficiently warmed up by the cooling water stored in the first heat storage unit 51 and the second heat storage unit 52. As a result, the engine 10 can be warmed up early, and fuel consumption can be improved.
Moreover, the heat (heat receiving) which cooling water receives from the 1st channel | path 20 into which exhaust gas flows can be suppressed because the 1st heat storage part 51 and the 2nd heat storage part 52 consist of a heat insulating material. Thereby, since it can suppress that the temperature of a cooling water rises, it can suppress that the cooling efficiency of the engine 10 by a cooling water falls. Further, it is possible to prevent the heat radiation of the cooling water whose temperature has been increased after heat exchange.

  In the above description, the switching valve 29 is used between the first passage 20, the second passage 25, and the third passage 27. However, the switching valve 29 is not limited to this. It may be a valve.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Heat exchange system 10 Engine 29 Switching valve 30 Heat exchanger 41 1st cooling water flow path 42 2nd cooling water flow path 45 1st valve 46 2nd valve 51 1st heat storage part 52 2nd heat storage part 61 1st temperature sensor 62 1st 2 temperature sensor 80 ECU

Claims (5)

Engine,
A heat exchanger that is provided in an exhaust passage through which the exhaust gas of the engine flows, and exchanges heat between the exhaust gas and the refrigerant;
A first flow path through which the refrigerant flows from the heat exchanger to the engine;
A second flow path through which the refrigerant flows from the engine to the heat exchanger;
A heat storage section provided in the first flow path and the second flow path for storing heat of the refrigerant;
A heat exchange system. A first valve that is provided on the engine side in the first flow path and the second flow path and opens or closes the flow path;
A second valve provided on the heat exchanger side in the first flow path and the second flow path to open or close the flow path,
The heat storage unit is provided between the first valve and the second valve.
The heat exchange system according to claim 1. A control unit that closes the flow path to the first valve and the second valve when the engine is stopped and opens the flow path to the first valve and the second valve when the engine is warmed up;
The heat exchange system according to claim 2. A first temperature detection sensor for detecting a temperature of the refrigerant in the first flow path;
A second temperature detection sensor for detecting the temperature of the refrigerant in the second flow path,
The control unit operates the first valve and the second valve when the engine is warmed up so that the refrigerant having the higher temperature of the refrigerant in the first flow path and the second flow path is supplied to the engine side. Flowing the refrigerant having the lower temperature to the heat exchanger,
The heat exchange system according to claim 3. An outside air flow path through which outside air flows via the heat exchanger;
A switching unit that switches a target to be heat-exchanged with the refrigerant in the heat exchanger to either the exhaust gas or the outside air;
The first flow path causes the refrigerant cooled by exchanging heat with the outside air in the heat exchanger to flow to the engine.
The heat exchange system according to any one of claims 1 to 4.

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