JP2009241780A - Circulating device for internal combustion engine - Google Patents

Abstract

An engine circulation device capable of suppressing the temperature drop of oil to a heat exchanger and improving the efficiency of heat exchange with cooling water in the heat exchanger.
A cooling water circulation path including a heat exchanger for exchanging heat between cooling water from an engine and oil and an exhaust heat recovery unit for exchanging heat between oil and exhaust heat of the engine. And an oil circulation path 2 provided with. The oil circulation path stores at least one of the heat from the oil exchanged with the cooling water by the heat exchanger and the heat from the oil exchanged with the exhaust heat by the exhaust heat recovery unit, A heat storage device 23 for releasing the stored latent heat to the oil is provided. Further, the oil circulation path is provided with limiting means 3 for bypassing the oil circulated from the heat storage device and the heat exchanger when the engine is cold started to the exhaust heat recovery device and restricting the oil circulation to the exhaust heat recovery device. Yes.
[Selection] Figure 1

Description

  The present invention relates to a circulation device for an internal combustion engine, and more particularly, to a measure for suppressing the temperature drop of a heat transport fluid that circulates during cold start of the internal combustion engine and improving the efficiency of heat exchange with cooling water.

  Conventionally, a heat transport fluid circulates, and a heat transport fluid circulation path including an exhaust heat exchange section that exchanges heat between the heat transport fluid and the exhaust heat of the engine, and cooling water from the engine circulates, A circulation device for an internal combustion engine is known that includes a cooling water circulation path including a heat exchange section that exchanges heat between the cooling water and the heat transport fluid (for example, see Patent Document 1). In this case, the heat transport fluid is heated by heat exchange with the exhaust heat of the engine in the exhaust heat exchange section, and is circulated through the heat transport fluid circulation path so that heat is exchanged with the cooling water in the heat exchange section. Yes. And the cooling water heated by exchanging heat with the heat transport fluid in the heat exchanging section is introduced into the engine and circulates in the cooling water circulation path so as to heat the inside of the engine.

Some heat transfer fluid circulation paths include a heat storage device in which a latent heat type heat storage material is accommodated in a container (see, for example, Patent Document 2). In this configuration, the heat storage material in the container of the heat storage device changes phase to the liquid phase by receiving heat from the heat transport fluid and stores latent heat, while releasing the latent heat to the heat transport fluid by phase change to the solid phase. It has become. When the engine is cold started, the heat transport fluid is heated by heat exchange between the exhaust heat of the engine and the latent heat of the heat storage material to heat the heat transport fluid to a higher temperature.
JP 2006-176042 A JP 2006-17436 A

  However, in any of the above conventional ones, an exhaust heat exchanging portion is provided in the middle of the exhaust path for exchanging heat with the exhaust heat. Therefore, heat exchange is performed during cold start of an internal combustion engine such as an engine. The heat transport fluid circulation path between the section and the exhaust heat exchange section is exposed to cold air, and the temperature of the heat transport fluid inside thereof is significantly reduced. In addition, when applied to an internal combustion engine such as a vehicle, if the heat exchange unit is accommodated in an accommodation space (for example, an engine room) of the internal combustion engine, heat between the heat exchange unit and the exhaust heat exchange unit is obtained. The transport fluid circulation path becomes very long. For this reason, even if the heat transport fluid is heated by the latent heat of the heat storage material, it circulates through the long and cold heat transport fluid circulation path between the heat exchange section and the exhaust heat exchange section when the internal combustion engine is cold started. During this time, the temperature is inevitably lowered, and the heat exchange efficiency with the cooling water in the heat exchange section is significantly deteriorated.

  The present invention has been made in view of such a point, and the object of the present invention is to suppress a temperature drop due to circulation of a heat transport fluid heated by latent heat from a heat storage device during a cold start of an internal combustion engine, An object of the present invention is to provide an internal combustion engine circulation device capable of improving the efficiency of heat exchange with cooling water in a heat exchange section.

  In order to achieve the above object, in the present invention, a heat transport fluid circulation path provided with an exhaust heat exchange section that circulates a heat transport fluid and exchanges heat between the heat transport fluid and exhaust heat of an internal combustion engine, It is premised on a circulation device for an internal combustion engine that includes a cooling water circulation path provided with a heat exchange section that circulates cooling water from the internal combustion engine and exchanges heat between the cooling water and the heat transport fluid. Further, the heat transport fluid circulation path includes an amount of heat from the heat transport fluid exchanged with the cooling water of the internal combustion engine by the heat exchange unit and a heat transport fluid exchanged with the exhaust heat by the exhaust heat exchange unit. A heat storage device is provided that stores at least one of the heat amounts of the heat, and releases the stored latent heat to the heat transport fluid. The heat transport fluid circulation path is provided with restriction means for restricting circulation of the heat transport fluid from the heat storage device and the heat exchange unit with respect to the exhaust heat exchange unit when the internal combustion engine is cold-started.

  Due to this specific matter, the heat transport fluid circulation path restricting means restricts the circulation of the heat transport fluid from the heat storage device and the heat exchange unit to the exhaust heat exchange unit at the cold start of the internal combustion engine. The heat transport fluid from the heat exchange section and the heat storage device is limited to the heat transport fluid whose temperature is significantly reduced inside the heat transport fluid circulation path near the exhaust heat exchange section exposed to cold air during cold start. And difficult to mix. In addition, the heat transport fluid circulation path between the heat exchange part accommodated in the accommodation space (engine room) of the internal combustion engine such as a vehicle and the exhaust heat exchange part for exchanging heat with the exhaust heat is very long. Even when the internal combustion engine is cold-started, circulation of the heat transport fluid from the heat exchange unit and the heat storage device to the exhaust heat exchange unit is limited and circulates in a short circuit. As a result, the temperature drop due to the circulation of the heat transport fluid heated by the latent heat released from the heat storage device during the cold start of the internal combustion engine is minimized, and the heat exchange efficiency with the cooling water in the heat exchange section is reduced. It becomes possible to improve.

  Further, the following configurations are listed as specifying the limiting means. That is, the limiting means includes a bypass passage for bypassing the circulation of the heat transport fluid from the heat storage device and the heat exchanging section to the exhaust heat exchanging section, and the bypass passage with respect to the bypass passage during a cold start of the internal combustion engine. The heat storage device and switching means for switching the heat transport fluid circulation path so as to circulate the heat transport fluid from the heat exchange section are provided.

  By this specific matter, the heat transport fluid from the heat exchange section heated by the latent heat released from the heat storage device during the cold start of the internal combustion engine passes through the heat transport fluid circulation path switched by the switching means, and the exhaust heat exchange section It circulates in the bypass passage with a short circuit without circulating until. Thereby, it is possible to configure the restricting means with a simple configuration of the bypass passage and the switching means.

  And when the temperature of the heat transport fluid in the vicinity of the exhaust heat exchange section becomes higher than the temperature of the heat transport fluid circulating in the bypass passage, the heat storage device and the heat exchange section for the exhaust heat exchange section When the heat transport fluid circulation path is switched by the restriction means so as to allow the heat transport fluid to circulate, the heat transport fluid heated by the heat exchange with the exhaust heat is efficiently heated in the exhaust heat exchange section. The heat exchange efficiency with the cooling water in the heat exchange part can be further improved by being led to the exchange part. In addition, when the temperature of the heat transport fluid in the vicinity of the exhaust heat exchange section becomes higher than the temperature of the heat transport fluid circulating in the bypass passage, the circulation of the heat transport fluid from the heat storage device and the heat exchange section is the exhaust heat exchange section. Therefore, it is possible to reliably prevent overheating of the heat transport fluid heated by heat exchange with the exhaust heat at the exhaust heat exchange section.

  Further, when the heater core for exchanging heat with the cooling water circulating through the cooling water circulation path is provided in the cooling water circulation path, the heat heated by the latent heat of the heat storage device at the cold start of the internal combustion engine The heater core is quickly heated by the transport fluid or the cooling water, and the immediate effect of the heating device using the heater core as a heat source can be improved.

  Further, when the heat exchange unit, the heat storage device, and the bypass passage are housed in the housing space of the internal combustion engine, heat transport that connects the heat exchange unit, the heat storage device, and the bypass passage with a short circuit. The length of the fluid circulation path is short, and it is possible to very efficiently prevent a temperature drop of the heat transport fluid that circulates during the cold start of the internal combustion engine.

  In short, at the time of cold start of the internal combustion engine, the circulation of the heat transport fluid from the heat exchange section that performs heat exchange with the cooling water is limited to the exhaust heat exchange section, and the heat transport fluid from the heat exchange section is short-circuited Minimize temperature drop due to circulation of heat transport fluid during cold start of internal combustion engine by circulating in circuit or prohibiting circulation of heat transport fluid to heat storage device that exchanges heat with cooling water Therefore, heat exchange efficiency with cooling water can be improved.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an overall configuration of a system when a circulation device according to an embodiment of the present invention is applied to a vehicle engine (internal combustion engine). In the figure, reference numeral 1 denotes a cooling water circulation path having one end connected to a cooling water inlet E11 and a cooling water outlet E12 of the engine E. In this cooling water circulation path 1, heat exchange as a heat exchange unit is performed. A vessel 11 and a heater core 12 are provided.

  Further, an exhaust heat recovery device 21 as an exhaust heat exchanging portion for recovering exhaust heat of the exhaust gas discharged from the engine E is provided in the middle of the exhaust pipe E2 connected to the exhaust manifold E1 of the engine E. . The exhaust heat recovery device 21 is provided in an oil circulation path (heat transport fluid circulation path) 2 that circulates oil as a heat transport fluid. The exhaust heat recovery device 21 is a conventionally known one that exchanges heat between the exhaust heat of the exhaust gas flowing through the exhaust pipe E2 and the oil circulating in the oil circulation path 2. In this case, the exhaust heat recovery device 21 is provided on the downstream side of the catalyst device that purifies the exhaust gas flowing in the exhaust pipe E2.

  The oil circulation path 2 is provided with an oil pump 22, a heat storage device 23, and the heat exchanger 11 in order from the downstream side of the exhaust heat recovery device 21. In the exhaust heat recovery device 21, heat exchange with the exhaust gas is performed. The oil heated by is circulated by the oil pump 22 so as to be returned to the exhaust heat recovery unit 21 through the heat storage device 23 and the heat exchanger 11 in order. Further, the heat exchanger 11 includes a storage container 111 into which the cooling water from the cooling water circulation path 1 flows. The storage vessel 111 has an upstream end connected to the downstream end of the forward pipe 1a of the cooling water circulation path 1 connected to the cooling water outlet E12 of the engine E, and a downstream end connected to the cooling water inlet E11 of the engine E. The cooling water circulation path 1 is connected to the upstream end of the return pipe 1b so that the cooling water circulating in the cooling water circulation path 1 flows in. As shown in FIG. 2, a spiral tube 24 spirally wound around the axis n of the storage container 111 is accommodated in the storage container 111. One end (right end in FIG. 2) of the spiral tube 24 is connected to the downstream end of the oil tube 2a of the oil circulation path 2 whose upstream end is connected to the heat storage device 23, while the other end ( The left end in FIG. 2 is connected to the upstream end of the oil pipe 2a of the oil circulation path 2 whose downstream end is connected to a switching valve 32 described later, and the oil in the oil circulation path 2 flowing in the spiral pipe 24 and Heat exchange is performed with the cooling water.

  In this case, a water pump is provided at the downstream end of the return pipe 1b of the cooling water circulation path 1, and the cooling water in the cooling water circulation path 1 is circulated by this water pump. In addition, upstream and downstream ends of a radiator circulation path for circulating cooling water to a radiator (not shown) are connected to the return pipe 1b on the downstream side of the heater core 12, respectively, by a thermostat provided at a connection portion with the radiator circulation path. When the temperature of the cooling water is low, such as when the engine E is cold started, circulation of the cooling water to the radiator via the radiator circulation path is prohibited. Further, the heater core 12 is provided in the return pipe 1 b of the cooling water circulation path 1.

As shown in FIG. 3, the heat storage device 23 includes a heat storage material storage container 231 filled with a latent heat storage material X made of, for example, sodium acetate trihydrate (CH ₃ COONa 3H ₂ O). Yes. In the heat storage material storage container 231, a spiral tube 25 wound in a spiral shape around the axis m of the heat storage material storage container 231 is stored. One end (right end in FIG. 3) of the spiral pipe 25 is connected to the downstream end of the oil pipe 2a of the oil circulation path 2 whose upstream end is connected to the discharge port of the oil pump 22, and the other end (left end in FIG. 3). Is connected to the upstream end of the oil pipe 2 a of the oil circulation path 2 whose downstream end is connected to the heat exchanger 11, and between the oil of the oil circulation path 2 flowing in the spiral pipe 25 and the heat storage material X. Heat exchange is performed.

  Sodium acetate trihydrate as the heat storage material X does not cause a phase change from the liquid phase to the solid phase even when cooled from a temperature state exceeding the melting point (58 ° C.) to a temperature state below the melting point, and minus 20 °. It has a characteristic of being in a supercooled state while storing latent heat from C to about minus 30 ° C. Inside the heat storage material storage container 231, a nucleation device that operates so as to promote the phase change of the heat storage material X is provided, and this nucleation device is operated by vibration generated when the engine E is started. When the heat storage material X is in a supercooled state and the nucleation device is activated by vibration generated at the start of the engine E, the phase change of the heat storage material X to the solid phase is promoted, and the spiral tube of the oil circulation path 2 The latent heat is quickly released from the oil circulating in the cylinder 25. Further, when the heat storage material X finishes releasing latent heat due to the phase change to the solid phase and receives heat from the oil circulating in the spiral tube 25 of the oil circulation path 2, the heat storage material X changes from the temperature state exceeding the melting point to the liquid phase. It changes to store latent heat.

  The oil circulation path 2 is provided with restriction means 3 for restricting the circulation of oil from the heat storage device 23 and the heat exchanger 11 to the exhaust heat recovery device 21 when the engine E is cold-started. The restricting means 3 includes a bypass passage 31 that bypasses oil circulation from the heat exchanger 11 and the heat storage device 23 (heat storage material container 231) to the exhaust heat recovery device 21, and a bypass passage 31 when the engine E is cold started. On the other hand, a switching valve 32 is provided as switching means for switching the oil circulation path 2 so that oil from the heat exchanger 11 and the heat storage device 23 is circulated. The upstream end of the bypass passage 31 is connected to the oil pipe 2a of the oil circulation path 2 located between the heat exchanger 11 and the exhaust heat recovery device 21, while the downstream end is connected to the exhaust heat recovery device 21 and the oil. It is connected to the oil pipe 2 a of the oil circulation path 2 located between the pump 22. The switching valve 32 is a three-way valve attached to the upstream end of the bypass passage 31, and the entire amount of oil heat-exchanged in the heat exchanger 11 is oiled via the exhaust heat recovery device 21 side or the bypass passage 31. The pump 22 is switched to circulate. Further, the switching valve 32 is configured such that when the temperature of the oil in the oil circulation path 2 near the exhaust heat recovery device 21 becomes higher than the temperature of the oil circulating in the bypass path 31, the heat exchanger 11 and the heat storage device 23. The oil circulation path 2 is switched so as to allow the oil to circulate from the exhaust gas to the exhaust heat recovery unit 21.

  As shown in FIG. 4, the heat exchanger 11, the heat storage device 23, the oil pump 22, the bypass passage 31, and the switching valve 32 are accommodated in an engine compartment E <b> 0 as an accommodation space for accommodating the engine E. Specifically, the heat exchanger 11 is accommodated on the left side of the engine E in the engine compartment E0. The heat storage device 23 is accommodated below the left headlamp E4 in the engine compartment E0. The oil pump 22 is accommodated immediately after the heat storage device 23 in the engine compartment E0. The bypass passage 31 extends in the left-right direction of the vehicle body immediately after the oil pump 22 in the engine compartment E0. The switching valve 32 is provided at the right end of the bypass passage 31. In this case, the oil pump 22 and the switching valve 32 are controlled by the ECU of the engine E composed of a digital computer.

  Therefore, in the above embodiment, when the engine E is cold started, oil from the heat storage device 23 and the heat exchanger 11 in the oil circulation path 2 flows into the oil pipe 2a between the heat exchanger 11 and the exhaust heat recovery device 21. The switching valve 32 is switched to the bypass passage 31 connected to the upstream end and connected to the oil pipe 2a between the exhaust heat recovery device 21 and the oil pump 22, and the exhaust heat recovery device is circulated. The circulation of oil from the heat storage device 23 and the heat exchanger 11 with respect to 21 is limited. For this reason, the oil from the heat exchanger 11 and the heat storage device 23 is used for the oil whose temperature is remarkably lowered in the oil circulation path 2 in the vicinity of the exhaust heat recovery device 21 exposed to the cold air during the cold start of the engine E. The oil circulation is limited and it will not mix. In addition, the oil circulation path 2 between the heat exchanger 11 in which the heat exchanger 11 is housed in the engine compartment E0 and the exhaust heat recovery unit 21 that performs heat exchange with the exhaust heat is very long. However, during the cold start of the engine E, the circulation of oil from the heat exchanger 11 and the heat storage device 23 to the exhaust heat recovery device 21 is limited, and the oil is circulated in a short circuit via the bypass passage 31. As a result, the temperature drop due to the circulation of the oil heated by the latent heat released from the heat storage device 23 during the cold start of the engine E is minimized, and the heat exchange efficiency with the cooling water in the heat exchanger 11 is improved. Can be improved.

  Further, when the engine E is cold started, the limiting means 3 for limiting the circulation of oil from the heat storage device 23 and the heat exchanger 11 to the exhaust heat recovery device 21 is constituted by the bypass passage 31 and the switching valve 32. The oil from the heat exchanger 11 heated by the latent heat released from the heat storage device 23 during the cold start of the engine E is circulated to the vicinity of the exhaust heat recovery device 21 by switching the oil circulation path 2 by the switching valve 32. Instead, the bypass passage 31 is circulated on the short circuit. Thereby, the restricting means 3 can be configured with a simple configuration of the bypass passage 31 and the switching valve 32.

  The switching valve 32 is connected to the exhaust heat recovery device 21 from the heat storage device 23 and the heat exchanger 11 when the temperature of the oil near the exhaust heat recovery device 21 becomes higher than the temperature of the oil circulating in the bypass passage 31. Therefore, the oil heated by the heat exchange with the exhaust heat in the exhaust heat recovery device 21 is efficiently guided to the heat exchanger 11, and the cooling water in the heat exchanger 11 is switched. The heat exchange efficiency with can be further improved. Moreover, when the temperature of the oil in the vicinity of the exhaust heat recovery device 21 becomes higher than the temperature of the oil circulating in the bypass passage 31, the oil circulation from the heat storage device 23 and the heat exchanger 11 to the exhaust heat recovery device 21 is performed. Since it is allowed, overheating of the oil heated by the heat exchange with the exhaust heat in the exhaust heat recovery device 21 can be reliably prevented.

  Further, since the heater core 12 is provided on the downstream side of the heat exchanger 11 in the return pipe 1b of the cooling water circulation path 1, heat exchange with the oil heated by the latent heat of the heat storage device 23 during the cold start of the engine E is performed. The cooling water immediately after being heated by the heat exchanger 11 flows into the heater core 12 and the heater core 12 is quickly heated, so that the immediate effect of the heating apparatus using the heater core 12 as a heat source can be improved.

  Furthermore, since the heat exchanger 11, the heat storage device 23, the oil pump 22, the bypass passage 31, and the switching valve 32 are accommodated in the engine compartment E0, the heat exchanger 11, the heat storage device 23, the oil pump 22, and the bypass passage 31 are accommodated. The length of the oil circulation path 2 that connects the two with a short circuit becomes short, and the temperature drop of the oil circulating when the engine E is cold started can be prevented very efficiently.

  In addition, this invention is not limited to the said embodiment, The other various modifications are included. For example, in the above embodiment, when the engine E is cold-started, the switching valve 32 is switched and circulated from the heat storage device 23 and the heat exchanger 11 of the oil circulation path 2 to the bypass passage 31 to circulate oil to the exhaust heat recovery device 21. However, another bypass passage is provided in parallel and another oil pump is provided near the downstream side of the exhaust heat recovery device. Oil may be circulated by another route by another oil pump. In this case, the temperature of the oil near the exhaust heat recovery device, that is, the temperature of the oil heated by heat exchange with the exhaust heat of the exhaust heat recovery device can be detected more accurately, and the oil temperature near the exhaust heat recovery device can be detected. It is possible to improve the switching accuracy of the switching valve that is switched when the temperature becomes higher than the temperature of the oil in the short circuit portion of the cooling water circulation path that circulates from the heat storage device and the heat exchanger through the bypass passage.

  Further, in the above embodiment, the switching valve 32 is configured to circulate the entire amount of oil heat-exchanged in the heat exchanger 11 during the cold start of the engine to the oil pump 22 through the exhaust heat recovery device 21 side or the bypass passage 31. However, the switching valve is configured to have an adjustable opening, and most of the heat exchanged in the heat exchanger is circulated to the oil pump through the bypass passage, while the remaining oil from the heat exchanger is circulated. May be circulated through the exhaust heat recovery unit to restrict the circulation of oil from the heat storage device and the heat exchanger to the exhaust heat recovery unit when the engine is cold-started.

  In the above-described embodiment, the case where the engine circulation device is applied to a vehicle has been described. However, the engine circulation device may be used for purposes other than the vehicle.

1 is a system configuration diagram illustrating an overall configuration of a system when a circulation device according to an embodiment of the present invention is applied to an engine of a vehicle. It is a perspective view which shows the structure inside a heat exchanger. It is a perspective view which shows the structure inside a thermal storage apparatus. It is a perspective view which shows the whole structure of the system in the state mounted in the motor vehicle.

Explanation of symbols

1 Cooling water circulation path 11 Heat exchanger (Heat exchange part)
12 Heater core 2 Oil circulation path (Heat transport fluid circulation path)
21 Exhaust heat recovery unit (exhaust heat exchanger)
23 heat storage device 3 limiting means 31 bypass passage 32 switching valve (switching means)
E engine (internal combustion engine)
E0 engine compartment (storage space for internal combustion engine)

Claims (5)

A heat transport fluid circulation path provided with an exhaust heat exchange section for circulating the heat transport fluid and exchanging heat between the heat transport fluid and the exhaust heat of the internal combustion engine;
Cooling water from the internal combustion engine circulates, and includes a cooling water circulation path provided with a heat exchange section for exchanging heat between the cooling water and the heat transport fluid,
In the heat transport fluid circulation path,
The amount of heat from the heat transport fluid exchanged with the cooling water of the internal combustion engine by the heat exchange unit and the amount of heat from the heat transport fluid exchanged with the exhaust heat by the exhaust heat exchange unit While storing heat, while being provided with a heat storage device that releases the stored latent heat to the heat transport fluid,
A circulating apparatus for an internal combustion engine, characterized by being provided with limiting means for limiting the circulation of the heat transport fluid from the heat storage device and the heat exchange unit to the exhaust heat exchange unit when the internal combustion engine is cold-started. The internal combustion engine circulation device according to claim 1,
The limiting means is
A bypass passage for bypassing circulation of the heat transport fluid from the heat storage device and the heat exchange unit to the exhaust heat exchange unit;
Switching means for switching the heat transport fluid circulation path so as to circulate the heat transport fluid from the heat storage device and the heat exchanging section to the bypass passage at the time of cold start of the internal combustion engine, A circulating device for an internal combustion engine. The internal combustion engine circulation device according to claim 2,
When the temperature of the heat transport fluid in the vicinity of the exhaust heat exchange section becomes higher than the temperature of the heat transport fluid circulating in the bypass passage, the limiting means includes the heat storage device and the heat exchange for the exhaust heat exchange section. A circulating apparatus for an internal combustion engine, wherein the heat transport fluid circulation path is switched so as to allow the heat transport fluid to circulate from the section. In the circulation device for an internal combustion engine according to any one of claims 1 to 3,
An internal combustion engine circulation device, wherein the cooling water circulation path is provided with a heater core for exchanging heat with the cooling water circulating through the cooling water circulation path. In the circulation device for an internal combustion engine according to any one of claims 2 to 4,
The internal combustion engine circulation device, wherein the heat exchange unit, the heat storage device, and the bypass passage are accommodated in an accommodation space of the internal combustion engine.

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