JP2010156315A - Engine waste heat utilizing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the recovery efficiency of waste heat, in a device utilizing the waste heat of an engine. <P>SOLUTION: This waste heat utilizing device 1 for utilizing the waste heat of the engine 2 includes a vapor generating part 5 for vaporizing a working fluid by the waste heat of an exhaust gas discharged from the engine 2, a working fluid passage 3 for circulating the vaporized working fluid, a coolant passage 4 circulated with the coolant used for cooling the engine 2, and a heat exchanger 6 laid in with the working fluid passage 3 and the coolant passage 4, and for exchanging the heat between the coolant and the working fluid. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a waste heat utilization device that effectively utilizes waste heat generated in an engine.

  2. Description of the Related Art Conventionally, there is known a waste heat utilization device that collects and uses waste heat energy generated by driving an engine via a fluid as a medium. In such a waste heat utilization device, for example, the working fluid vaporized by the heat of the exhaust gas of the engine is supplied to the heat exchanger, and the temperature of the other fluid is raised by the heat exchanger warmed up by this. Some use the energy of waste heat.

  An improvement of such a waste heat utilization device is disclosed in Patent Document 1. In the heating device of Patent Document 1, the energy of waste heat recovered from the exhaust gas is used for heating in the vehicle.

  In the heating device of Patent Document 1, steam that has recovered waste heat energy from exhaust gas warms up the condenser, and the air that flows in the duct by the operation of the blower warms the heater core in series with the condenser and passes through the heater core. The room is heated by blowing air.

Japanese Utility Model Publication No. 4-24805

  By the way, in the warming-up apparatus of patent document 1, in order to utilize the energy of the waste heat collect | recovered from exhaust gas for temperature rising of engine cooling water, it is necessary to operate a fan. Accordingly, since electric power for operating the blower is consumed, there is room for improvement in terms of overall waste heat recovery efficiency.

  Therefore, an object of the present invention is to improve waste heat recovery efficiency in an apparatus that uses engine waste heat.

  The engine waste heat utilization device of the present invention that solves such a problem includes a steam generator that vaporizes a working fluid by waste heat of exhaust gas discharged from the engine, and an operation in which the vaporized working fluid circulates. A fluid passage, a refrigerant passage through which a refrigerant used for cooling the engine circulates, and a heat exchanger in which the working fluid passage and the refrigerant passage are drawn and heat exchange is performed between the refrigerant and the working fluid. It is characterized by that.

  With such a configuration, the working fluid vaporized in the steam generator can flow through the working fluid passage by utilizing the difference in specific volume between the liquid-phase working fluid and the vaporized working fluid. it can. As a result, the waste heat utilization device for an engine of the present invention generates a flow of a vaporized working fluid without using a pump or a blower, thereby realizing highly efficient waste heat recovery without energy loss such as electric power. Can do.

  In such an engine waste heat utilization device, based on a control valve for changing the flow rate of the working fluid in the working fluid passage, grasping means for grasping a warm-up state of the engine, and a grasping result by the grasping means And a control means for controlling the open state of the control valve.

  With such a configuration, the heat energy recovered from the exhaust gas can be used for raising the temperature of the engine cooling refrigerant at a time when the temperature of the engine cooling refrigerant is low, for example, at a warm-up time at the time of starting the engine. . Thereby, an engine can be warmed up early.

  In the engine waste heat utilization apparatus, the steam generator includes a steam generation chamber in which the working fluid is vaporized, and the operation that is vaporized and formed in an upper portion of the steam generation chamber. A lead-out port for leading the fluid to the working fluid passage; and an inlet for introducing the working fluid liquefied by heat exchange in the heat exchanger into the steam generation chamber, formed at the bottom of the steam generation chamber. Can be configured.

  By adopting such a configuration, it is possible to circulate the working fluid without using a pump by utilizing the fact that the vaporized working fluid has a larger specific volume than the liquid-phase working fluid. Since the vaporized working fluid has a small specific gravity, it moves upward in the steam generation chamber. For this reason, the vaporized working fluid is likely to accumulate above the inside of the steam generation chamber, and the vaporized working fluid accumulated in this way can move from the outlet provided in the upper part to the working fluid passage. Further, since the working fluid expands when it is vaporized, the steam that loses its place in the steam generating chamber is led out from the outlet to the working fluid passage. Thus, the vaporized working fluid can flow toward the heat exchanger in the working fluid passage without using a pump.

  In such an engine waste heat utilization device, the steam generator includes a steam generation chamber in which the working fluid is vaporized, and the vaporized working fluid formed in an upper portion of the steam generation chamber. An outlet for leading to the working fluid passage, an inlet for introducing the working fluid formed at the bottom of the steam generation chamber and liquefied by heat exchange in the heat exchanger into the steam generation chamber, and the steam generation A reserve tank for the working fluid communicated with a chamber, and a pressure regulating valve installed in a passage communicating with the reserve tank and the steam generation chamber, and a liquid level of the working fluid in a liquid phase in the steam generation chamber And a gap between the outlet and the outlet.

  By adopting such a configuration, it is possible to prevent the liquid-phase working fluid from blocking the working fluid passage and preventing the inflow of steam. Further, the steam generation chamber can be maintained at a constant pressure. Thereby, the vaporized working fluid can be stably supplied to the heat exchanger.

  In the engine waste heat utilization apparatus, the heat exchanger may have a structure in which a ventilation passage is formed so that air for indoor heating of the vehicle exchanges heat with the refrigerant and the working fluid.

  By setting it as such a structure, even if it is before completion of engine warm-up, it can heat-up indoor ventilation using the thermal energy collect | recovered from exhaust gas. For this reason, the room can be heated immediately after the engine is started.

  In the engine waste heat utilization device, the steam generator may be disposed downstream of an exhaust heat utilization unit that utilizes heat of exhaust gas in an exhaust pipe of the engine.

By setting it as such a structure, the function of the exhaust-heat utilization part which exhibits the function using the heat | fever of exhaust gas can be maintained. If the steam generator is arranged on the upstream side of such an exhaust heat utilization part, the temperature of the exhaust gas is lowered by the steam generator, so that the necessary heat quantity may not be supplied to the exhaust heat utilization part. . Therefore, the present invention has a configuration in which the steam generator is arranged on the downstream side of the exhaust heat utilization section. Examples of such an exhaust heat utilization unit include an oxidation-reduction catalyst and an O ₂ sensor.

  The engine waste heat utilization apparatus according to the present invention can generate a flow of vaporized working fluid without using a pump, and can realize highly efficient waste heat recovery without energy loss such as electric power.

It is explanatory drawing which showed schematic structure of the waste heat utilization apparatus of the engine of this invention. It is explanatory drawing which expanded and showed the working fluid channel | path in FIG. 1, and a steam generator. It is explanatory drawing which showed the pressure regulation valve, Comprising: (a) shows the case where a working fluid moves from a steam generation chamber into a reserve tank, (b) shows that a working fluid moves from a reserve tank to a steam generation chamber It is explanatory drawing which showed the case where it does. It is explanatory drawing which showed the heat exchanger, (a) shows the external appearance of a heat exchanger, (b) shows the AA cross section in (a), (c) is (a) and ( It is explanatory drawing which expanded and showed the BB cross section in b). It is the flow of control about the early warming-up and early heating which C / U processes.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for implementing the present invention will be described in detail with reference to the drawings.

  Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of a waste heat utilization apparatus 1 of the present invention. The waste heat utilization apparatus 1 is assembled to an engine 2 mounted on a vehicle. The waste heat utilization apparatus 1 includes a working fluid passage 3 through which a working fluid circulates and a refrigerant passage 4 through which a refrigerant used for cooling the engine 2 circulates.

  The working fluid passage 3 is connected to a steam generator 5 that vaporizes the working fluid by waste heat of exhaust gas discharged from the engine 2. Further, the working fluid passage 3 is drawn into the heat exchanger 6. The working fluid passage 3 includes a pipe 31 on the upstream side of the heat exchanger 6 and a pipe 32 on the downstream side of the heat exchanger 6.

  The refrigerant passage 4 includes a refrigerant pipe 41. A water jacket 2 a that forms a part of the refrigerant passage 4 is formed in the engine 2. The refrigerant pipe 41 and the water jacket 2a are connected to form a loop path through which the refrigerant circulates. The refrigerant pipe 41 is drawn into the heat exchanger 6. In the heat exchanger 6, the working fluid vapor flowing through the working fluid passage 3 drawn into the inside exchanges heat with the refrigerant flowing through the refrigerant pipe 41 drawn into the inside. The refrigerant passage 4 is assembled with a device having a function for efficiently cooling the engine 2 such as a water pump, a thermostat, and a radiator.

  The engine 2 includes an exhaust pipe 7 that exhausts exhaust gas discharged from the engine 2 to the outside. A reduction catalyst 8 is disposed in the exhaust pipe 7. The reduction catalyst 8 is warmed up using the heat of the exhaust gas discharged from the engine 2 and exhibits a reduction function.

  Next, the steam generator 5 will be described. FIG. 2 is an explanatory view showing the working fluid passage 3 and the steam generator 5 in FIG. 1 in an enlarged manner. The steam generator 5 includes a steam generation chamber 50 that stores a working fluid. The steam generation chamber 50 is assembled to the exhaust pipe 7 on the downstream side of the reduction catalyst 8, and is formed so that the exhaust pipe 7 penetrates the inside of the steam generation chamber 50. Further, the steam generation chamber 50 has an outlet 52 formed in the upper part 51 and an inlet 54 formed in the bottom 53. The outlet 52 is connected to the piping 31, that is, the working fluid passage 3. The introduction port 54 is connected to the pipe 32, that is, the working fluid passage 3. Further, the diameter Φa of the pipe 31 of the working fluid passage 3 is larger than the diameter Φb of the pipe 32 for the purpose of preventing the backflow of the working fluid.

  Further, the steam generator 5 includes a reserve tank 9 maintained at a constant pressure. The steam generation chamber 50 and the reserve tank 9 are connected by a communication path 10. The reserve tank 9 stores a working fluid in a liquid state. A pressure regulating valve 11 is disposed in the communication path 10.

  FIG. 3 is an explanatory view showing the pressure regulating valve 11. 3A shows a case where the working fluid moves from the inside of the steam generation chamber 50 into the reserve tank 9, and FIG. 3B shows a case where the working fluid moves from the inside of the reserve tank 9 into the steam generation chamber 50. It is explanatory drawing which showed the case.

  The pressure regulating valve 11 includes a housing 11a in which a flow path for the working fluid is formed, a relief valve 11b, a vacuum valve 11c, a relief pressure adjusting spring 11d that applies a biasing force to the relief valve 11b, and a vacuum pressure control that applies a biasing force to the vacuum valve 11c. A spring 11e is provided.

  The open / close state of the pressure regulating valve 11 changes depending on the pressure in the steam generation chamber 50. In a normal state where the pressure in the steam generation chamber 50 is generated and flowed without any obstacles, both the relief valve 11b and the vacuum valve 11c are closed. When the pressure in the steam generation chamber 50 rises and a pressing force exceeding the urging force of the relief pressure adjusting spring 11d is applied to the relief valve 11b, the relief valve 11b is opened as shown in FIG. The working fluid flows from the generation chamber 50 into the reserve tank 9. At this time, the vacuum valve 11c is in a closed state. On the other hand, when the pressure in the steam generation chamber 50 decreases and a suction force exceeding the biasing force by the vacuum pressure adjusting spring 11e is applied to the vacuum valve 11c, the vacuum valve 11c opens as shown in FIG. The working fluid flows from the reserve tank 9 into the steam generation chamber 50. At this time, the relief valve 11b is closed. By this pressure regulating valve 11, the liquid-phase working fluid stored in the steam generation chamber 50 is adjusted so that a gap is provided between the liquid level of the working fluid and the outlet 52. Thereby, it is suppressed that the liquid-phase working fluid closes the working fluid passage and prevents the inflow of steam. Further, the amount of refrigerant in the steam generation chamber 50 is kept, and the pressure in the steam generation chamber 50 is kept constant.

  Next, the heat exchanger 6 will be described. FIG. 4 is an explanatory view showing the heat exchanger 6. 4A shows the appearance of the heat exchanger 6, FIG. 4B shows the AA cross section in FIG. 4A, and FIG. 4C shows FIGS. 4A and 4B. It is explanatory drawing which expanded and showed the BB cross section in (b). 4A, the heat exchanger 6 includes an upper tank 61, a lower tank 62, several tubes 63 communicating with the inside of the upper tank 61 and the lower tank 62, and fins 64 arranged side by side between the tubes 63. It has.

  As shown in FIG. 4B, the upper tank 61 is divided into two rooms 61b and 61c by a partition wall 61a. The pipe 31 is connected to the room 61b, and the refrigerant pipe 41 is connected to the room 61c. Yes. Similarly, the lower tank 62 is also divided into chambers 62b and 62c by a partition wall 62a. The piping 32 is connected to the chamber 62b, and the refrigerant piping 41 is connected to the chamber 63c. As shown in FIGS. 4B and 4C, the tube 63 has a passage 63b and a passage 63c formed by a partition wall 63a. The passage 63b communicates the room 61b and the room 62b. The passage 63c communicates the room 61c and the room 62c. Further, the gap formed by the tube 63 and the fin 64 is a ventilation passage 65 through which the air sent by the operation of the blower 12 shown in FIG. 1 passes.

  Next, the working fluid and refrigerant flow and heat exchange in the waste heat utilization apparatus 1 will be described.

  The working fluid stored in the steam generation chamber 50 is vaporized by the waste heat of the exhaust gas that passes through the exhaust pipe 7. Since the vaporized working fluid has a larger specific volume than the liquid-phase working fluid, it floats upward in the steam generation chamber 50. Furthermore, since the working fluid expands when it is vaporized from the liquid state, the working fluid loses its place in the vapor generating chamber 50 and is led out from the outlet 52 into the working fluid pipe 31. Since the working fluid is continuously vaporized and pushes the preceding steam, the working fluid flows in the pipe 31 and the working fluid moves toward the heat exchanger 6. Thus, the working fluid in the vapor state flowing in the pipe 31 flows into the chamber 61 b of the upper tank 61 from the steam pipe 31. The working fluid that has flowed into the chamber 61 b of the upper tank 61 flows into the passage 63 b of the plurality of tubes 63.

  On the other hand, the refrigerant is supplied from the refrigerant pipe 41 into the room 62 c of the lower tank 62. The refrigerant supplied into the chamber 62c of the lower tank 62 flows into the passage 63c. The working fluid flowing in the passage 63b and the refrigerant flowing in the passage 63c exchange heat through the partition wall 63a. The working fluid flowing through the passage 63b exchanges heat with the air passing through the air passage 65. Thereby, the warmed air blows up the vehicle interior.

  The working fluid that passes through the passage 63b is condensed by releasing heat by heat exchange with the refrigerant or blowing air, and returns to the liquid phase. Since the working fluid in the liquid state has a specific gravity greater than that of the working fluid in the vapor state, it flows into the chamber 62b of the lower tank 62 by gravity. The working fluid in the chamber 62 b of the lower tank 62 is sent to the steam generation chamber 50 side through the pipe 32 due to gravity, and is introduced into the steam generation chamber 50 through the introduction port 54.

  On the other hand, the refrigerant flowing through the passage 63c collects heat from the working fluid and rises in temperature at a low temperature during cold start. Further, at the time of high temperature after the completion of warming, heat is released to the air and the air is warmed while being cooled. At this time, the warmed air blows up the vehicle interior.

  Moreover, as shown in FIG. 1, the waste heat utilization apparatus 1 is provided with the temperature sensor 13 which measures the temperature of the refrigerant | coolant in the engine 2, and the air-conditioning switch 14 for a user to request indoor heating. The temperature sensor 13 corresponds to the grasping means of the present invention for grasping the warm-up state of the engine 2 from the refrigerant temperature in the engine 2. The temperature sensor 13 and the air conditioning switch 14 are electrically connected to a C / U (Control Unit) 15. Further, the waste heat utilization apparatus 1 includes a first control valve 16 and a second control valve 17. The first control valve 16 is disposed on the pipe 31 and changes the flow rate of the working fluid in the pipe 31 by changing the open / close state. The second control valve 17 is disposed between the engine 2 on the refrigerant pipe 41 and the heat exchanger 6, and changes the open / closed state, whereby the refrigerant in the refrigerant pipe 41 flowing into the heat exchanger 6 is changed. Change the flow rate. Each of the first control valve 16 and the second control valve 17 is electrically connected to the C / U 15. The C / U 15 determines the open state of each of the first control valve 16 and the second control valve 17 based on the refrigerant temperature information acquired from the temperature sensor 13 and the ON / OFF information of the air conditioning switch 14. A command signal is sent to control each valve. Moreover, C / U15 and the air blower 12 are electrically connected, and the air blower 12 is drive | operated based on the command signal of C / U15.

  Next, control processing for early warm-up and early heating according to the present invention will be described. This control process is performed by the C / U 15. FIG. 5 is a flow of control processing for early warm-up and early heating. Hereinafter, the control processing of the present invention will be described with reference to the flow of FIG.

  In step S1, C / U 15 acquires the refrigerant temperature. Here, the C / U 15 acquires the temperature in the engine 2 measured by the temperature sensor 13. When the C / U 15 finishes the process of step S1, the process proceeds to step S2.

  In step S2, C / U 15 determines whether or not the refrigerant temperature acquired in step S1 is equal to or lower than a predetermined value Thw. Here, the predetermined value Thw is the temperature of the refrigerant when the engine 2 has been warmed up.

  If C / U 15 determines YES in step S2, that is, if the refrigerant temperature acquired in step S1 is equal to or lower than a predetermined value Thw, the process proceeds to step S3.

  In step S3, the C / U 15 determines whether or not there is a room heating request. Here, the C / U 15 determines that there is a heating request based on the ON information of the air conditioning switch 14. If the C / U 15 determines YES in step S3, that is, if the information on the ON of the air conditioning switch 14 is acquired, the process proceeds to step S4.

  In step S4, the C / U 15 determines to open the first control valve 16 and close the second control valve 17. Further, the C / U 15 transmits a signal indicating the determined valve state to each of the first control valve 16 and the second control valve 17. In addition, an operation start signal is sent to the blower 12 to start blowing into the room.

  When C / U 15 determines YES in step S2, that is, during cold operation when the engine 2 is not warmed up, the temperature of the refrigerant is low, so even if the refrigerant is supplied to the heat exchanger 6, The amount of heat for warming the air for indoor heating cannot be obtained. Even in this case, since the working fluid that has recovered the amount of heat from the exhaust gas is in a higher temperature than the refrigerant and has the amount of heat that warms the air for indoor heating, the working fluid is supplied to the heat exchanger 6 to operate. The air for room heating is warmed by the heat of the fluid to heat the room. This makes it possible to heat the room earlier than before.

  By the way, if C / U 15 determines NO in step S2, that is, if the refrigerant temperature acquired in step S1 is higher than the predetermined value Thw, the process proceeds to step S5.

  In step S5, the C / U 15 determines to close the first control valve 16 and open the second control valve 17. Further, the C / U 15 transmits a signal indicating the determined valve state to each of the first control valve 16 and the second control valve 17.

  When the C / U 15 determines NO in step S2, that is, when the engine 2 has been warmed up, the refrigerant has a high temperature and can warm the air for indoor heating. Therefore, when there is a heating request in this case, the air for indoor heating is raised to a temperature sufficient to warm the room only by heat exchange with the refrigerant. For this reason, it is set as the structure which supplies only a refrigerant | coolant to the heat exchanger 6. FIG.

  Further, if the C / U 15 determines NO in step S3, that is, if the information on the air-conditioning switch 14 is not acquired, the process proceeds to step S6.

  In step S6, the C / U 15 determines to open the first control valve 16 and open the second control valve 17. Further, the C / U 15 transmits a signal indicating the determined valve state to each of the first control valve 16 and the second control valve 17.

  When the C / U 15 determines NO in step S3, that is, during the cold operation before the completion of warm-up, and when there is no heating request, the waste heat utilization device 1 uses the amount of heat recovered from the exhaust gas to increase the refrigerant. Used to warm up the engine 2 As a result, warm-up is promoted, and effects such as improved fuel efficiency can be obtained.

  Further, as in the present invention, the recovery of the thermal energy of the exhaust gas to the indoor warm air via the working fluid is considered to occur when the exhaust gas and the air for indoor heating are directly subjected to heat exchange. This has the effect of suppressing fluctuations in the air conditioning temperature due to the invasion of toxic gas into the air and the temperature change of the exhaust gas.

  In the present embodiment, the refrigerant temperature in the water jacket 2a is acquired to determine whether or not the engine 2 has been warmed up. Based on temperature information correlated with the refrigerant temperature in the water jacket 2a. Judgment can be made. In addition, any information that can determine whether or not the engine 2 has been warmed up can be determined based on other information.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope.

DESCRIPTION OF SYMBOLS 1 Waste heat utilization apparatus 2 Engine 3 Working fluid passage 31, 32 Piping 4 Refrigerant passage 41 Refrigerant piping 5 Steam generator 50 Steam generation chamber 52 Outlet port 54 Inlet port 6 Heat exchanger 65 Air passage 7 Exhaust pipe 8 Reduction catalyst 9 Reserve tank 11 Pressure regulating valve 13 Temperature sensor 14 Air conditioning switch 15 C / U (control unit)
16 First control valve 17 Second control valve

Claims (6)

A steam generator that vaporizes the working fluid by waste heat of exhaust gas exhausted from the engine;
A working fluid passage through which the vaporized working fluid circulates;
A refrigerant passage through which a refrigerant used for cooling the engine circulates;
A heat exchanger in which the working fluid passage and the refrigerant passage are drawn, and the refrigerant and the working fluid exchange heat;
An engine waste heat utilization device characterized by comprising: The engine waste heat utilization apparatus according to claim 1,
A control valve for varying the flow rate of the working fluid in the working fluid passage;
Grasping means for grasping a warm-up state of the engine;
Control means for controlling the open state of the control valve based on temperature information measured by the temperature measuring means;
An engine waste heat utilization device characterized by comprising: The engine waste heat utilization apparatus according to claim 1 or 2,
The steam generator
A steam generation chamber in which the working fluid is vaporized;
A lead-out port formed at the upper part of the steam generation chamber for leading the vaporized working fluid to a working fluid passage;
An inlet for introducing the working fluid formed at the bottom of the steam generation chamber and liquefied by heat exchange in the heat exchanger into the steam generation chamber;
An engine waste heat utilization device characterized by comprising: The engine waste heat utilization apparatus according to claim 1 or 2,
The steam generator
A steam generation chamber in which the working fluid is vaporized;
A lead-out port that is formed in the upper part of the steam generation chamber and leads the vaporized working fluid to the working fluid passage;
An inlet for introducing the working fluid formed at the bottom of the steam generation chamber and liquefied by heat exchange in the heat exchanger into the steam generation chamber;
A reserve tank for the working fluid in communication with the steam generation chamber;
A pressure regulating valve installed in a passage communicating the reserve tank and the steam generation chamber;
With
A waste heat utilization apparatus for an engine, wherein a gap is provided between a liquid level of the working fluid in a liquid phase in the steam generation chamber and the outlet. The engine waste heat utilization apparatus according to any one of claims 1 to 4,
The waste heat utilization apparatus for an engine, wherein the heat exchanger is formed with a ventilation passage so that air for indoor heating of the vehicle exchanges heat with the refrigerant and the working fluid. The engine waste heat utilization apparatus according to any one of claims 1 to 5,
The waste heat utilization device for an engine, wherein the steam generator is disposed downstream of an exhaust heat utilization unit that utilizes heat of exhaust gas in an exhaust pipe of the engine.

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