JP2004270487A - Engine exhaust heat utilization device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively reduce emission of engine exhaust gas by promoting warming-up from the engine starting. <P>SOLUTION: The exhaust heat using device comprises a heat exchanger 18 for carrying out heat exchange between the engine exhaust gas and water, a first circulating circuit 22 for circulating the heat-exchanged water, a heat storage tank 23 for storing the heat of the water, an electric pump 24, and heat pipes 29, 30 for heat contacting with the water. The water is circulated in the first circulating circuit 22 by the electric pump 24 for warming the heat pipes 29, 30 and using the exhaust heat. The device also comprises a water jacket 5 for circulating the water, a second circulating circuit 34 for circulating the water into the jacket 5 so as to supply the heat stored in the heat storage tank 23 to the jacket 5, valves 28, 10, 25 for switching the water circulation from the first circulating circuit 22 to the second circulating circuit 34, and a controller 40. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an engine mounted on a vehicle such as an automobile, and more particularly, to an exhaust heat utilization device for utilizing exhaust heat of an engine for warming up.
[0002]
[Prior art]
DESCRIPTION OF RELATED ART Conventionally, as this kind of exhaust heat utilization apparatus, there exists a thing described in the following patent document 1, for example. This device is provided in a lubricating oil path for circulating lubricating oil in the internal combustion engine, an oil pump provided in the middle of the lubricating oil path, a bypass passage branching from a part of the exhaust pipe of the internal combustion engine, and a bypass passage. A heat exchanger, a heat storage material accommodated in the heat exchanger and storing heat by heat exchange with waste heat, and a heat insulating member disposed around the heat exchanger, and a lubricating oil path is formed by the heat exchanger. In thermal contact with As a result, immediately after the start of the internal combustion engine, the lubricating oil exchanges heat with the heat stored in the heat storage material capable of keeping the temperature at a high temperature for a long time, thereby promoting warm-up. On the other hand, after the start of the internal combustion engine, the lubricating oil exchanges heat with the exhaust heat and the heat storage material, so that the warm-up can be quickly performed. In addition, since the lubricating oil is warmed up by bringing the lubricating oil path and the heat exchanger into thermal contact with each other, a portion of the internal combustion engine that needs to be warmed up is directly warmed up. As a result, sliding friction of the internal combustion engine is reduced, fuel efficiency is improved, and emissions are reduced.
[0003]
[Patent Document 1]
JP-A-7-119455 (pages 2 to 4, FIGS. 1 to 3)
[0004]
[Problems to be solved by the invention]
However, in the device described in Patent Literature 1, since the warm-up is performed using the lubricating oil as a heat medium, only the specific portion to which the lubricating oil is supplied can be warmed up. There was a problem that there was no immediate effect on the machine and the reduction of exhaust emissions was insufficient.
[0005]
The present invention has been made in view of the above circumstances, and has as its object to promote the warm-up of an engine from the start of the engine, thereby effectively reducing the exhaust heat of the engine. It is to provide a utilization device.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 circulates a heat exchanger for performing heat exchange between an exhaust of an engine and a heat medium, and a heat medium exchanged by the heat exchanger. A first circulation circuit, a heat storage tank for storing heat of the heat medium in the first circulation circuit, an electric pump for supplying a flow to the heat medium in the first circulation circuit, and a heat medium in the first circulation circuit. An exhaust heat utilization device for an engine, comprising: a heat utilization medium that is in thermal contact with the exhaust heat, wherein the heat utilization medium is heated by circulating the heat medium by an electric pump in the first circulation circuit to warm the heat utilization medium, A heat medium passage provided in the engine for circulating the heat medium, a second circulation circuit for circulating the heat medium to the heat medium passage for supplying heat stored in the heat storage tank to the heat medium passage, and an engine. of During machine, and purpose, further comprising a switching means for switching the circulation in the first circulation circuit of the heat medium circulating in the second circulation circuit.
[0007]
According to the configuration of the present invention, when the engine is operated, by driving the electric pump, a flow is given to the heat medium, and the heat medium circulates in the first circulation circuit. At this time, heat is exchanged between the exhaust gas of the engine and the heat medium in the heat exchanger, and heat given to the heat medium is stored in the heat storage tank. Further, the heat medium circulating in the first circulation circuit comes into thermal contact with the heat utilization medium, whereby the heat utilization medium is warmed and the exhaust heat is used. Here, when the engine is warmed up, the switching of the heat medium in the first circulation circuit is switched to the circulation in the second circulation circuit by the switching means, so that the heat medium circulates through the heat medium passage provided in the engine. The engine is warmed up by the heat stored in the heat storage tank.
[0008]
In order to achieve the above object, the invention according to claim 2 is characterized in that, in the invention according to claim 1, the heat utilization medium is any one of engine oil, differential gear oil, and automatic transmission fluid. .
[0009]
According to the configuration of the invention described above, in addition to the operation of the invention described in claim 1, any one of engine oil, differential gear oil, and automatic transmission fluid is warmed and exhaust heat is used to lubricate the engine and lubricate the differential gear. Or, the smooth operation of the automatic transmission is promoted.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a device for utilizing exhaust heat of an engine of the present invention will be described in detail with reference to the drawings.
[0011]
FIG. 1 shows a conceptual configuration diagram of an exhaust heat utilization device for an engine. This exhaust heat utilization device is applied to an engine of an automobile (not shown). This vehicle is equipped with an engine 1, an automatic transmission as a power transmission device for transmitting the output of the engine 1 to driving wheels, a differential gear, and the like (not shown).
[0012]
The engine 1 includes a cylinder block 2 and an engine head 3. The engine 1 is provided with a water-cooled cooling device that circulates cooling water to cool the engine 1. The cooling device includes a water pump (W / P) 4 provided in the engine 1, a water jacket 5 provided inside the cylinder block 2 and the engine head 3, a radiator 6 for radiating cooling water, and a radiator. 6, a thermostat 7 provided on the downstream side, a heater core 8 for utilizing the heat of the cooling water for heating the passenger compartment, a cooling water passage 9 connecting these devices and the like 4 to 8, a cooling water and the like. And a first three-way valve 10 for switching the flow of air. In this embodiment, the water jacket 5 and the cooling water passage 9 correspond to a heat medium passage of the present invention for circulating circulating water as a heat medium of the present invention. The first three-way valve 10 includes a first inlet 10a and a second inlet 10b, and one outlet 10c. The first three-way valve 10 is an electromagnetic valve that switches the communication of the outlet 10c with the first inlet 10a or the second inlet 10b by an actuator. The water pump 4 is for giving a flow to and circulating the cooling water. In the cooling water passage 9, the cooling water flowing out of the water jacket 5 branches into a flow toward the radiator 6 and the first three-way valve 10. The cooling water flowing to the radiator 6 flows to the water pump 4 via the thermostat 7 and flows again to the water jacket 5. The cooling water flowing to the first three-way valve 10 flows to the water pump 4 via the heater core 8 by switching the valve 10, and flows again to the water jacket 5. The engine 1 is provided with a cooling water temperature sensor 11 for detecting a cooling water temperature. The engine 1 includes an intake passage (not shown) for sucking air and an exhaust passage 12 for discharging exhaust gas. A catalytic converter 13 is provided in the exhaust passage 12.
[0013]
A heat exchange unit 14 is provided in the exhaust passage 12. The heat exchange unit 14 includes an exhaust pipe 15 continuous with the exhaust passage 12, an exhaust switching valve 16 provided on the inlet side of the exhaust pipe 15, a bypass pipe 17 branched from the valve 16, and an intermediate portion of the pipe 17. And a heat exchanger 18 provided. The exhaust switching valve 16 is an electric valve driven by an actuator, and switches exhaust gas discharged from the engine 1 to the exhaust passage 12 between a flow to the exhaust pipe 15 and a flow to the bypass pipe 17. The exhaust gas flowing from the exhaust switching valve 16 to the bypass pipe 17 returns to the exhaust pipe 15 after passing through the heat exchanger 18 and is discharged to the outside through the exhaust passage 12. The heat exchanger 18 is for exchanging heat between exhaust gas flowing through the bypass pipe 17 and circulating water as a heat medium.
[0014]
FIG. 2 shows an example of the heat exchange unit 14 in a side view. FIG. 3 shows an enlarged cross section taken along line AA of FIG. As shown in FIG. 3, in the heat exchanger 18, a plurality of tubes 20 are arranged in parallel in a cylindrical shell 19 through which exhaust gas passes. Both ends of these tubes 20 are connected to one inlet pipe 21 and one outlet pipe, respectively (only the inlet pipe 21 is shown in FIG. 2).
[0015]
The heat exchanger 18 is provided with a first circulation circuit 22 for circulating the circulating water heat exchanged by the heat exchanger 18. In FIG. 1, the first circulation circuit 22 is indicated by a thick broken line. The first circulation circuit 22 is connected between the inlet pipe 21 and the outlet pipe of the heat exchanger 18. A heat storage tank 23 for storing heat of the circulating water in the first circulation circuit 22 is provided in the middle of the first circulation circuit 22. The heat storage tank 23 can store high-temperature circulating water. In this embodiment, the heat storage tank 23 has a capacity of 2 to 3 liters and is covered with a heat insulating material. This tank 23 can keep the circulating water warm in the range of “50 to 70 ° C.” for “about 36 hours”.
[0016]
In the first circulation circuit 22, an electric pump 24 for providing a flow to the circulating water in the same circuit 22 is provided downstream of the heat storage tank 23. In the first circulation circuit 22, a second three-way valve 25 is provided downstream of the electric pump 24. The second three-way valve 25 includes one inlet 25a, a first outlet 25b, and a second outlet 25c. The second three-way valve 25 is an electrically operated valve that switches the communication of the inlet 25a with the first outlet 25b or the second outlet 25c by an actuator. On the downstream side of the heat exchanger 18, a reserve tank 26 for absorbing a change in the amount of circulating water is provided. The reserve tank 26 is provided with a relief valve 27. In the first circulation circuit 22, an on-off valve 28 is provided downstream of the reserve tank 26. The on-off valve 28 is an electromagnetic valve that is opened and closed to allow or cut off the flow of circulating water in the first circulation circuit 22. Similarly, in the first circulation circuit 22, a plurality of heating pipes 29 and 30 for heating various oils and the like as heat utilization media related to various devices are provided upstream of the heat storage tank 23. These heating pipes 29 and 30 are provided in contact with the first circulation circuit 22 so that the circulating water is in thermal contact with various oils and the like. Therefore, when the engine 1 is operating, the circulating water is heated by the heat exchanger 18 by circulating the circulating water by the electric pump 24 in the first circulation circuit 22. Then, when the circulating water passes through the heating pipes 29 and 30, various oils and the like are warmed, so that the exhaust heat of the engine 1 is used. One heating pipe 29 is provided with a circulating water temperature sensor 31 for detecting the circulating water temperature. In this embodiment, the various oils include any of engine oil, differential gear oil, and automatic transmission fluid.
[0017]
Connection pipes 32 and 33 are provided between the first circulation circuit 22 and the cooling water passage 9. That is, the connection pipe 32 is connected between the vicinity of the downstream side of the on-off valve 28 in the first circulation circuit 22 and the vicinity of the downstream side of the heater core 8 in the cooling water passage 9. A connection pipe 33 is connected between the second three-way valve 25 in the first circulation circuit 22 and the first three-way valve 10 in the cooling water passage 9. The connection pipes 32 and 33 and the cooling water passage 9 provide a second circulation circuit 34 according to the present invention for circulating circulating water to the water jacket 5 in order to supply heat stored in the heat storage tank 18 to the water jacket 5. Is configured.
[0018]
In this embodiment, a controller 40 for controlling the exhaust switching valve 16, the electric pump 24, the on-off valve 28, the first three-way valve 10, and the second three-way valve 25 is provided. The controller 40 is connected with the exhaust switching valve 16, the electric pump 24, the on-off valve 28, the first three-way valve 10, and the second three-way valve 25. The circulating water temperature sensor 31 and the cooling water temperature sensor 11 are also connected to the controller 40. An ignition switch (IGSW) 41 is connected to the controller 40. The controller 40 includes a known CPU, ROM, and RAM. The ROM stores a control program for the exhaust heat utilization device. The controller 40 switches the circulation of the circulating water in the first circulation circuit 22 to the circulation in the second circulation circuit 34 when the engine 1 is warmed up. The two-way valve 25 is controlled. In this embodiment, the exhaust switching valve 16, the on-off valve 28, the first three-way valve 10, the second three-way valve 25, and the controller 40 correspond to switching means of the present invention for switching circulation of circulating water.
[0019]
FIG. 4 is a flowchart showing the control program. The controller 40 executes this routine periodically at predetermined intervals.
[0020]
First, in step 100, the controller 40 reads the state of the engine 1 before starting. In this embodiment, the controller 40 reads the value of the coolant temperature detected by the coolant temperature sensor 11. In this state, the exhaust switching valve 16 is turned on, the on-off valve 28 is turned off, and the first three-way valve 10 and the second three-way valve 25 are turned on.
[0021]
Here, “on” of the exhaust gas switching valve 16 means a switching state in which the exhaust gas flows to the bypass pipe 17, and “off” in the opposite sense means a switching state in which the exhaust gas flows to the exhaust pipe 15. . “On” of the on-off valve 28 means an open state, and the opposite “off” means a closed state. “On” of the first three-way valve 10 means a switching state in which circulating water flowing through the connection pipe 33 flows to the heater core 8, and “Off” on the contrary indicates that the cooling water flowing out of the water jacket 5 is supplied to the heater core 8. Means the switching state to flow to “On” of the second three-way valve 25 means a switching state in which the circulating water flowing out of the electric pump 24 flows to the connection pipe 33, and the opposite “off” means that the circulating water flowing out of the electric pump 24 is turned off. This means a switching state of flowing to the heat exchanger 18.
[0022]
In step 110, the controller 40 determines whether or not the engine 1 needs to be warmed up by heat storage. The controller 40 makes this determination based on the read coolant temperature value. Here, if the cooling water temperature is high and warm-up is not necessary, the controller 40 proceeds to step 150 without performing any processing. If the cooling water temperature is low and warm-up is required, the controller 40 shifts the processing to step 120.
[0023]
In step 120, the controller 40 turns on the electric pump 24. Next, the controller 40 waits for a predetermined time to elapse in Step 130, and then turns off the electric pump 24 in Step 140. Therefore, while the electric pump 24 is turned on, the circulating water circulates in the second circulation circuit 34 as shown by the solid line arrow in FIG. 1, and the circulating water flows to the cooling water passage 9 and the water jacket 5 of the engine 1. Sent. At this time, the heat stored in the heat storage tank 23 is supplied to the cooling water passage 9 and the water jacket 5 by the circulating water through the second circulation circuit 34.
[0024]
Next, in step 150, the controller 40 turns on the on-off valve 28 and turns off the first three-way valve 10 and the second three-way valve 25. Thereby, in the first circulation circuit 22, the flow of the circulating water from the reserve tank 26 to the heating pipes 29 and 30 is allowed. In the circuit 22, the state in which the circulating water from the electric pump 24 flows to the connection pipe 33 is switched to the state to flow to the heat exchanger 18. Further, in the cooling water circuit 9, the flow of circulating water from the connection pipe 33 to the heater core 8 is cut off, and the flow of cooling water from the water jacket 5 of the engine 1 to the heater core 8 is allowed.
[0025]
Next, the controller 40 waits until the IGSW 41 is turned on in step 160, that is, the engine 1 is started, and then turns on the exhaust switching valve 16 in step 170. As a result, the exhaust gas in the exhaust passage 12 flows to the bypass pipe 17, and the circulating water in the heat exchanger 18 is heated by the exhaust heat.
[0026]
Next, in step 180, the controller 40 turns on the electric pump 24. As a result, the circulating water circulates in the first circulation circuit 22 as shown by the dashed arrow in FIG. As a result, the heat of the circulating water warmed by the heat exchanger 18 is stored in the heat storage tank 23.
[0027]
Thereafter, in step 190, the controller 40 determines whether the circulating water temperature detected by the circulating water temperature sensor 31 is higher than a predetermined value. If the determination result is negative, the controller 40 repeats the processing of steps 180 and 190, and continues storing heat in the heat storage tank 23. If this determination result is affirmative, the controller 40 turns off the exhaust gas switching valve 16 in step 200. As a result, the state in which the exhaust gas in the exhaust passage 12 flows to the exhaust pipe 15 is switched.
[0028]
Thereafter, in step 210, the controller 40 determines whether or not the IGSW 41 has been turned off. If this determination result is negative, the engine 1 is operating and the controller 40 repeats the processing of steps 180 to 210. If this determination result is affirmative, the engine 1 is stopped, and the controller 40 shifts the processing to step 220.
[0029]
In step 220, the controller 40 turns off the electric pump 24. Next, at step 230, the controller 40 turns on the exhaust gas switching valve 16. As a result, the state in which the exhaust gas in the exhaust passage 12 flows to the bypass pipe 17 is switched.
[0030]
Thereafter, at step 240, the controller 40 turns off the on-off valve 28 and turns on the first three-way valve 10 and the second three-way valve 25. Thereby, the state in which the circulating water flowing out of the electric pump 24 flows from the heat exchanger 18 to the connection pipe 33 is switched to a state in which the flow of the circulating water from the reserve tank 26 to the heating pipes 29 and 30 is cut off.
[0031]
According to the exhaust heat utilization device for an engine of the embodiment described above, when the circulating water temperature is not higher than a predetermined value during operation of the engine 1, a flow is given to the circulating water by the electric pump 24 so that the circulating water is The first circulation circuit 22 is circulated. At this time, the heat exchanger 18 exchanges heat between the exhaust gas of the engine 1 and the circulating water, and the heat storage tank 23 stores heat given to the circulating water. Further, the circulating water circulating in the first circulation circuit 22 is brought into thermal contact with various oils and the like by the heating pipes 29 and 30, so that the oil and the like are warmed and the exhaust heat is used.
[0032]
Here, when the engine 1 needs to be warmed up, the circulation of the circulating water in the first circulation circuit 22 is switched to the circulation in the second circulation circuit 34 under the control of the controller 40, and the heat stored in the heat storage tank 23 is reduced. The water is supplied to the cooling water passage 9 and the water jacket 5 by the circulating water. Therefore, the circulating water circulates through the cooling water passage 9 and the water jacket 5, and the heat stored in the heat storage tank 23 warms up the engine 1. Since this warm-up is performed by flowing cooling water through the water jacket 5, it is possible to use the heat stored in the heat storage tank 23 effectively to warm up the entire engine 1 with immediate effect. it can. As a result, the warm-up of the engine 1 from the start can be promoted, and the exhaust emission of the engine 1 can be effectively reduced.
[0033]
In this embodiment, since various oils and the like heated by the heating pipes 29 and 30 are any of engine oil, differential gear oil, and automatic transmission fluid, they are heated and exhaust heat is used. Therefore, lubrication of the engine 1, lubrication of the differential gear, or smooth operation of the automatic transmission is promoted. Thereby, the fuel efficiency of the engine 1 can be improved.
[0034]
It should be noted that the present invention is not limited to the above-described embodiment, and can be carried out as follows without departing from the spirit of the invention.
[0035]
For example, in the above-described embodiment, circulating water is circulated through the second circulation circuit 34, and the circulating water flows through the cooling water passage 9 and the water jacket 5 to supply the heat stored in the heat storage tank 23 to the engine 1. I did it. On the other hand, a passage dedicated to circulating water may be provided as a heat medium passage in the engine, and the circulating water may flow through the passage to supply the heat stored in the heat storage tank to the engine. In this case, the heat medium may be a liquid other than the circulating water.
[0036]
【The invention's effect】
According to the first aspect of the invention, the warm-up of the engine can be promoted from the start of the engine, and the exhaust emission of the engine can be effectively reduced.
[0037]
According to the second aspect of the invention, in addition to the effects of the first aspect of the invention, it is possible to improve the fuel efficiency of the engine.
[Brief description of the drawings]
FIG. 1 is a conceptual configuration diagram showing an exhaust heat utilization device according to an embodiment.
FIG. 2 is a side view showing the heat exchange unit.
FIG. 3 is a sectional view taken along line AA of FIG. 2;
FIG. 4 is a flowchart showing a control program.
[Explanation of symbols]
1 engine 5 water jacket (heat medium passage)
10 First three-way valve 16 Exhaust switching valve 18 Heat exchanger 22 First circulation circuit 23 Heat storage tank 24 Electric pump 25 Second three-way valve 29 Heating pipe 30 Heating pipe 34 Second circulation circuit 40 Controller

Claims (2)

A heat exchanger for exchanging heat between the exhaust gas of the engine and the heat medium,
A first circulation circuit for circulating the heat medium exchanged by the heat exchanger;
A heat storage tank for storing heat of the heat medium in the first circulation circuit;
An electric pump for providing a flow to the heat medium in the first circulation circuit;
A heat utilization medium that is in thermal contact with the heat medium in the first circulation circuit; and the exhaust heat is utilized by circulating the heat medium by the electric pump in the first circulation circuit to warm the heat utilization medium. The exhaust heat utilization device of the engine,
A heat medium passage provided in the engine to circulate the heat medium,
A second circulation circuit for circulating the heat medium to the heat medium passage to supply heat stored in the heat storage tank to the heat medium passage;
A switching device for switching the circulation of the heat medium in the first circulation circuit to the circulation in the second circulation circuit when the engine is warmed up. The exhaust heat utilization device for an engine according to claim 1, wherein the heat utilization medium is any one of engine oil, differential gear oil, and automatic transmission fluid.

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