KR102135646B1 - Exhaust heat storage system of vehicle - Google Patents

Abstract

The present invention relates to an exhaust heat accumulator of a vehicle, having a heat accumulator for storing the heat of the recovered exhaust, and using heat stored in the heat accumulator during cold start to speed up warm-up to save fuel and reduce pollutant emissions. And heating is possible as soon as the engine starts.

Description

Exhaust heat storage system of vehicle

The present invention relates to an exhaust heat storage device for automobiles, and more particularly, to an exhaust heat storage device for automobiles that can be used for cold starting of engines and indoor heating after storing the exhaust heat as cooling water and storing it in a heat storage device.

The engine of a vehicle is a power generation device for a vehicle that enables driving by converting thermal energy generated by burning fuel into kinetic energy and transmitting it to a wheel through a drive line.

However, the energy used for driving the vehicle is only a part of the total generated energy, and most of the energy is dissipated and dissipated into the atmosphere in the form of thermal energy by exhausting the surfaces of the engine and exhaust system.

Among them, the energy loss due to the exhaust of high-temperature exhaust gas is particularly large, so a part of exhaust heat is recovered and used for indoor heating by applying an exhaust heat recovery system (EHRS).

The conventional exhaust heat recovery device, as shown in Figure 1, is provided with a heat exchanger (3) surrounding the outer circumferential surface of the exhaust pipe (2), the engine (1) and the heat exchanger (3) and the heater for indoor heating (4) It consists of a structure in which a circulating cooling water pipe (5) is installed.

Therefore, the cooling water discharged from the engine 1 absorbs and heats the exhaust gas while passing through the heat exchanger 3 installed in the exhaust pipe 2, and then passes the heater 4 to supply the air supplied to the room. Warming is done. That is, the energy utilization rate is improved by recovering the heat of exhaust gas that has been discharged from the engine 1 and then discharged to the atmosphere through the exhaust pipe 2 for use in indoor heating.

As described above, an exhaust heat recovery device for recovering exhaust heat with cooling water is disclosed in Korean Patent Application Publication No. 10-2012-0080867 (Automotive Components Research Institute, Cooling Water Preheating Device Using Exhaust Heat), and Patent Publication No. 10-2012-0133487 (Disense ( Note)/Gongju University Industry-University Cooperation Foundation, Automotive exhaust heat recovery device).

However, the conventional exhaust heat recovery device immediately after starting, that is, when the temperature of the exhaust gas and the exhaust pipe 2 is not sufficiently increased, the amount of cooling water is small, so the improvement effect of the engine warm-up performance is small, and immediately after starting in winter for the same reason There was a problem that indoor heating was impossible.

Accordingly, the present invention has been devised to solve the above problems, and reduces the fuel consumption, reduces the generation of contaminants, and reduces the generation of pollutants by achieving an early warm-up during cold start. The purpose is to provide.

The present invention for achieving the above object, a bypass cooling water pipe installed to form a dual path in the exhaust cooling water pipe connecting the heat exchanger for exhaust heat recovery installed in the exhaust pipe of the engine and the heater for indoor heating, and the exhaust cooling water pipe and the bypass It is installed at the branch point of the pass cooling water pipe and includes a flow path control valve for controlling the cooling water flow path and a heat accumulator installed in the bypass cooling water pipe.

The present invention, a first cooling water temperature sensor for measuring the temperature of the cooling water discharged from the heat exchanger for exhaust heat recovery is installed in the discharge cooling water pipe, the bypass cooling water pipe for measuring the temperature of the cooling water discharged from the regenerator 2 cooling water temperature sensor is installed, and further comprising an electronic control unit for controlling the operation of the flow path control valve using the measured values of the first cooling water temperature sensor and the second cooling water temperature sensor.

When the measured value of the first cooling water temperature sensor is smaller than the measured value of the second cooling water temperature sensor, the electronic control unit determines the engine warm-up stage, controls the flow path control valve to shut off the discharge cooling water pipe and opens the bypass cooling water pipe. So that all the coolant goes through the heat accumulator.

When the measured value of the first cooling water temperature sensor is greater than or equal to the measured value of the second cooling water temperature sensor, the electronic control unit determines that it is a warm-up step, and controls the flow path control valve to open the discharge cooling water pipe and block the bypass cooling water pipe. Make sure that all coolant goes through the heater for indoor heating, not through the heat accumulator.

The electronic control unit judges the driving step when the measured value of the first cooling water temperature sensor is higher than the set thermostat opening temperature, and controls the flow path control valve to open both the discharge cooling water pipe and the bypass cooling water pipe to open the cooling water accumulator. Make sure that it flows through both the non-via path and the path via the heat accumulator.

The regenerator includes a heat exchanger for heat storage through which cooling water passes, an inner case in which a heat exchanger for heat storage is built, an outer case in which an inner case is built, and a heat storage material filled in a space between the heat exchanger for heat storage and the inner case.

An insulating space is formed between the inner case and the outer case.

The insulation space is formed by vacuum.

Insulating material is installed in the insulating space.

The cooling water inlet and outlet of the heat exchanger for heat storage protrude through the cover of the outer case.

The heat storage material injection hole formed in the inner case protrudes to the outside through the cover of the outer case.

A sealing is installed at the top of the opening for the interior of the inner case of the outer case to seal the gap between the cover covering the opening.

According to the present invention as described above, by using the heat stored in the accumulator immediately after start-up to heat the cooling water to quickly achieve engine warm-up, fuel consumption at the beginning of start is reduced, thereby improving fuel efficiency.

In addition, since the engine warm-up is performed quickly, the amount of air pollutants generated in a large amount at the initial start-up can be reduced.

In addition, the cooling water heated while passing through the heat accumulator passes through the heater for indoor heating, thereby enabling indoor heating immediately after starting.

1 is a block diagram of a vehicle exhaust heat recovery device according to the prior art.
2 is a block diagram of an exhaust heat storage device for a vehicle according to the present invention.
3 is an operation explanatory diagram of the present invention in the engine warm-up phase.
Figure 4 is an explanatory view of the operation of the present invention before the cooling of the cooling water by the radiator after the engine wormham.
5 is an operation explanatory diagram of the present invention in the traveling step in which cooling water is cooled by a radiator.
6 is a perspective view of a heat accumulator which is one configuration of the present invention.
Fig. 7 is a sectional view taken along line II in Fig. 6, and is a schematic longitudinal sectional view of the regenerator.

The present invention can be applied to various changes and can have various embodiments, and specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. The thickness of the lines or the size of components shown in the accompanying drawings may be exaggerated for clarity and convenience.

In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to a user's or operator's intention or precedent. Therefore, definitions of these terms should be made based on the contents throughout this specification.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a configuration diagram of an exhaust heat storage device of a vehicle according to the present invention, the present invention is the exhaust heat recovery heat exchanger 30 installed in the exhaust pipe 20 of the engine 10 and the heater 40 for indoor heating discharge Bypass cooling water pipe (24) installed to form a dual path in the cooling water pipe (22), and installed at the branch points of the discharge cooling water pipe (22) and the bypass cooling water pipe (24) flow path control valve (50) for controlling the cooling water flow path ) And a heat accumulator 60 installed in the bypass cooling water pipe 24.

The heat exchanger 30 for exhaust heat recovery is installed in a form surrounding the outer circumference of the exhaust pipe 20 connected to the engine 10. A muffler is installed at the end of the exhaust pipe 20.

The inlet cooling water pipe 21 is connected between the engine 10 and the heat exchanger 30 for exhaust heat recovery, and the discharge cooling water pipe 22 is provided between the heat exchanger 30 for exhaust heat recovery and the heater 40 for indoor heating. The cooling water pipe 23 is connected between the heater 40 for indoor heating and the engine 10. Therefore, the cooling water discharged from the engine 10 returns to the engine 10 via the heat exchanger 30 for exhaust heat recovery and the heater 40 for indoor heating, and the cooling water can use the heat of the exhaust gas for indoor heating. have.

The bypass cooling water pipe 24 is connected to one side of the discharge cooling water pipe 22 and the other side of the downstream of the discharge cooling water pipe 22, thereby forming a path of cooling water supplied to the heater 40 for indoor heating in two paths. .

A flow path control valve 50 is installed at the branching point between the discharge cooling water pipe 22 and the bypass cooling water pipe 24. The flow control valve 50 is controlled by the electronic control unit 70, depending on the operating state, only the discharge cooling water pipe 22 is opened, only the bypass cooling water pipe 24 is opened, or the discharge cooling water pipe 22 ) And the bypass cooling water pipe 24 are both opened.

The first cooling water temperature sensor 81 and the second cooling water temperature sensor are respectively provided at the rear end of the heat exchanger 30 for recovering the exhaust heat of the discharge cooling water pipe 21 and the rear end of the heat accumulator 60 of the bypass cooling water pipe 24, respectively. 82) is installed. The first cooling water temperature sensor 81 and the second cooling water temperature sensor 82 transmit the measured cooling water temperature value to the electronic control unit 70.

The electronic control unit 70 may be an engine control unit that controls the operation of the engine and discharges the heat exchanger 30 for recovering exhaust heat measured by the first cooling water temperature sensor 81 and the second cooling water temperature sensor 82. The cooling water temperature value and the discharge cooling water temperature value of the heat accumulator 60 are used for control of the flow path control valve 50.

The electronic control unit 70 controls the flow path regulating valve 50 by dividing it into an engine warm-up step, a warm-up step, and a driving step.

The electronic control unit 70 controls the flow control valve 50 to be opened only toward the bypass cooling water pipe 24 in the warm-up step immediately after the engine starts (see FIG. 3), and the flow control valve 50 in the warm-up step. Is controlled to open only toward the discharge cooling water pipe 22 (see FIG. 4 ), and in the subsequent driving step, the flow path control valve 50 is opened so that both the discharge cooling water pipe 22 and the bypass cooling water pipe 24 are opened. Control (see FIG. 5).

The electronic control unit 70 recognizes the engine start by the engine start switch on signal, and the outlet temperature value of the heat exchanger for recovering exhaust heat measured by the first cooling water temperature sensor 81 is measured by the second cooling water temperature sensor 82 When it is lower than the outlet temperature value of the accumulator, it is judged as the engine warm-up stage.

And, when the temperature of the outlet temperature of the heat exchanger for recovering exhaust heat from the first cooling water temperature sensor 81 is greater than or equal to the value of the outlet temperature of the heat accumulator of the second cooling water temperature sensor 82, the engine warm-up stage is determined.

Finally, when the exit temperature value of the heat exchanger for recovering exhaust heat from the first cooling water temperature sensor 81 is greater than or equal to the thermostat opening temperature, it is determined as the driving step. The thermostat opening temperature is generally about 85°C, and in the present invention, it is used as a reference value for determining the driving step (i.e., determining whether excess heat is generated) by setting it to an appropriate value slightly above.

The heat accumulator 60 spaces the heat exchanger for heat storage 61 and the heat exchanger for heat storage 61 through which the cooling water discharged from the heat exchanger 30 for exhaust heat recovery passes, as shown in FIGS. 6 and 7. It consists of an inner case (62) surrounding the space, and an outer case (63) surrounding the inner case (62) with space.

The heat exchanger for heat storage 61 has inlets 61a and outlets 61b formed on both sides of the upper surface. The inlet 61a and the outlet 61b are respectively connected to both ends of the heat accumulator 60 of the bypass cooling water pipe 24 to form a cooling water path through the heat exchanger 61 for heat storage.

In the center of the upper surface of the inner case 62, a heat storage material inlet 62a is formed.

The outer case 63 is provided with a cover 63a covering the upper surface, and the cover 63a has an inlet 61a and an outlet 61b of the heat exchanger 61 for heat storage, and a heat storage material inlet of the inner case 62 Through holes are formed at the corresponding positions of (62a), the inlet (61a) and the outlet (61b) and the heat storage material inlet (62a) is projected to the upper side of the cover (63a) through each through hole.

The upper edge portion of the outer case 63 is fitted with a rubber-like sealing 66 to seal the gap between the outer case 63 and the cover 63a.

A heat storage material 64 is filled in a space between the heat exchanger for heat storage 61 and the inner case 62. The heat storage material 64 is injected into the inner space of the inner case 62 through the heat storage material injection hole 62a. As the heat storage material, a phase change material called a phase change material (PCM) or a molten salt may be used.

As described above, since the heat storage material 64 surrounds the heat exchanger 61 for heat storage, when the cooling water discharged from the heat exchanger 30 for exhaust heat recovery passes through the heat exchanger 61 for heat storage, the heat of the cooling water Heat is transferred to the heat storage material 64 and heat is stored in the heat storage material 64.

The space between the inner case 62 and the outer case 63 is an insulating space 65, which can be formed as a simple empty space or a vacuum space, or a heat insulating material can be installed. As the insulation material, a new material insulation airgel may be filled or a vacuum insulation panel may be installed.

The heat transfer between the inner case 62 and the outer case 63 is suppressed as much as possible by the insulating space 65 provided with the insulating material, so that heat stored in the heat storage material 64 can be preserved for a long time.

As described above, the heat accumulator 60 absorbs heat from the cooling water that has recovered the exhaust heat while passing through the heat exchanger 30 for exhaust heat recovery, and stores heat storage.

Now, the operation and effects of the present invention will be described.

If the engine is started and the outlet temperature value of the heat exchanger for recovering exhaust heat measured by the first cooling water temperature sensor 81 is smaller than the outlet temperature value of the heat accumulator measured by the second cooling water temperature sensor 82, as an engine warm-up step, the electronic The control unit 70 operates the flow path control valve 50, as shown in FIG. 3, the discharge cooling water pipe 22 is closed and the bypass cooling water pipe 24 is opened.

At this time, the heat accumulating in the previous driving step is stored in the heat accumulator 60.

Therefore, when the cooling water path is controlled as described above, the cooling water discharged from the heat exchanger 30 for exhaust heat recovery may be heated once again by absorbing heat from the heat accumulator 60 while passing through the heat accumulator 60. The cooling water heated through the heat accumulator 60 passes through the heater 40 for indoor heating and returns to the engine 10 through the return cooling water pipe 23.

As described above, since the cooling water is heated by the heat accumulator 60 as well as the heat exchanger 30 for recovering the engine 10 and the exhaust heat, the temperature increase rate is improved, so that the engine warm-up is performed early. Therefore, during the initial cold-start operation, fuel consumption is reduced by reducing fuel consumption since it is not necessary to artificially increase the fuel supply amount by the engine control logic for rapid warm-up, thereby increasing the engine speed.

In addition, after cooling water absorbs the heat of the heat accumulator 60, the air blown into the room can be heated while passing through the heater 40 for indoor heating, thereby enabling indoor heating even after starting. That is, even in winter, it is possible to immediately start heating with starting.

When the engine is continuously operated and the cooling water temperature is improved, the engine warms up when the outlet temperature value of the heat exchanger for recovering the exhaust heat of the first cooling water temperature sensor 81 is greater than or equal to the outlet temperature value of the heat accumulator of the second cooling water temperature sensor 82. It is judged that the post-warm-up phase is over.

In this step, the electronic control unit 70 operates the flow path regulating valve 50 to open the discharge cooling water pipe 22 and close the bypass cooling water pipe 24 as shown in FIG. 4. In this step, since the heat accumulator 60 can no longer heat the cooling water, the cooling water flow toward the heat accumulator 60 is blocked, so that all the cooling water flows through the discharge cooling water pipe 22 to the heater 40 for indoor heating. All of the heat of the cooling water heated in the engine 10 and the heat exchanger 30 for recovering exhaust heat is used for indoor heating.

Subsequently, when the time elapses, the temperature of the coolant rises further, and the thermostat is opened, and the coolant circulates not only the heating circulation path described above, but also a circulation path for cooling water cooling (not shown) circulating through the engine and the radiator. This step is a driving step in which normal running is performed, and cooling of cooling water is required, that is, a step in which excess heat is generated in the cooling water, and the excess heat is stored in the heat accumulator 60.

Therefore, when the outlet temperature value of the heat exchanger for recovering exhaust heat of the first cooling water temperature sensor 81 is greater than or equal to the thermostat opening temperature, the electronic control unit 70 determines that it is a driving step, and as shown in FIG. 5, the flow control valve 50 ) To open both the discharge cooling water pipe 22 and the bypass cooling water pipe 24.

Therefore, since the cooling water flows through both the exhaust cooling water pipe 22 and the bypass cooling water pipe 24, the heat absorbed by the engine 10 and the heat exchanger 30 for recovering exhaust heat is used for indoor heating and a heat accumulator. It becomes available for heat storage of (60).

In the driving step, the heat stored in the heat accumulator 60 is stored in the heat accumulator 60 in a vehicle stop (engine stop) state, and when the engine starts to start the vehicle operation, the engine warms up quickly and immediately in the room. Used for heating.

On the other hand, the heat accumulator 60 effectively heats from the cooling water by the double case structure consisting of the inner case 61 and the outer case 62, the heat storage performance of the heat storage material 64, and the heat insulation performance of the heat insulation space 65. It can be absorbed and stored, and the stored heat can be maintained for a long time. Since detailed description thereof has already been made in the configuration description of the heat accumulator 60, further description is omitted.

As described above, according to the present invention, fuel consumption during cold start in winter can be reduced, pollutant emissions can be reduced, and indoor heating is possible immediately after start-up by storing heat energy that is wasted into the air while driving the vehicle and can be used when necessary. Do.

As described above, the present invention has been described with reference to the embodiment shown in the drawings, but this is only exemplary, and those skilled in the art to which the art pertains have various modifications and other equivalent embodiments You will understand that it is possible. Therefore, the true technical protection scope of the present invention should be defined by the claims below.

10: engine 20: exhaust pipe
21: inlet cooling water pipe 22: discharge cooling water pipe
23: return cooling water pipe 24: bypass cooling water pipe
30: heat exchanger for exhaust heat recovery 40: heater for indoor heating
50: flow control valve 60: heat storage
70: electronic control unit 81: first cooling water temperature sensor
82: second cooling water temperature sensor

Claims (12)

A bypass cooling water pipe (24) installed to form a dual path in the exhaust cooling water pipe (22) connecting the heat exchanger (30) for exhaust heat recovery installed in the exhaust pipe (20) of the engine (10) and the heater (40) for indoor heating ,
A flow path control valve (50) is installed at the branch points of the discharge cooling water pipe (22) and the bypass cooling water pipe (24) to control the cooling water flow path, and
It includes a heat storage (60) installed in the bypass cooling water pipe (24),
A first cooling water temperature sensor 81 that measures the temperature of the cooling water discharged from the heat exchanger 30 for recovering exhaust heat is installed in the discharge cooling water pipe 22, and a heat accumulator 60 is installed in the bypass cooling water pipe 24. ) Is installed a second cooling water temperature sensor 82 for measuring the temperature of the cooling water discharged from the flow control valve using the measured values of the first cooling water temperature sensor 81 and the second cooling water temperature sensor 82 ( 50) further comprising an electronic control unit 70 for controlling the operation,
When the measured value of the first cooling water temperature sensor 81 is greater than or equal to the measured value of the second cooling water temperature sensor 82, it is determined as a warm-up step, and the discharge cooling water pipe 22 is opened by controlling the flow path control valve 50. And by blocking the bypass cooling water pipe 24, the exhaust heat storage device of the vehicle so that all the cooling water is passed through the heater 40 for indoor heating without going through the heat storage (60). delete The method according to claim 1,
The electronic control unit 70 determines the engine warm-up step when the measured value of the first cooling water temperature sensor 81 is smaller than the measured value of the second cooling water temperature sensor 82, and controls the flow control valve 50 Exhaust heat storage device of a vehicle, characterized in that to block the exhaust cooling water pipe (22) and open the bypass cooling water pipe (24) so that all cooling water passes through the heat storage (60).
delete The method according to claim 1,
The electronic control unit 70 determines the driving step when the measured value of the first cooling water temperature sensor 81 is equal to or higher than the set thermostat opening temperature, and controls the flow control valve 50 to discharge the cooling water pipe 22 and the bi Exhaust heat storage device of a vehicle, characterized in that by opening all of the pass cooling water pipe (24), the cooling water flows through both the path that does not pass through the heat accumulator (60) and the path that passes through the heat accumulator (60).
The method according to claim 1,
The heat accumulator 60 is a heat exchanger for heat storage 61 through which cooling water passes, an inner case 62 in which a heat exchanger for heat storage 61 is built, and an outer case 63 in which an inner case 62 is built. And a heat storage material (64) filled in a space between the heat exchanger (61) for heat storage and the inner case (62).
The method according to claim 6,
Exhaust heat storage device of a vehicle, characterized in that the insulation space 65 is formed between the inner case (62) and the outer case (63).
The method according to claim 7,
Exhaust heat storage device of the vehicle, characterized in that the insulating space 65 is a vacuum.
The method according to claim 7,
Exhaust heat storage device of a vehicle, characterized in that the insulation is installed in the heat insulation space (65).
The method according to claim 6,
Cooling water inlet (61a) and the outlet (61b) of the heat exchanger for heat storage (61) passes through the cover (63a) of the outer case (63) protruding outside the exhaust heat storage device of a vehicle.
The method according to claim 6,
Exhaust heat storage device of a vehicle, characterized in that the heat storage material injection hole (62a) formed in the inner case (62) penetrates the cover (63a) of the outer case (63) and protrudes to the outside.
The method according to claim 6,
The exhaust heat storage device of a vehicle, characterized in that a seal (66) is installed at the top of the opening for the interior of the inner case (62) of the outer case (63), and the gap between the cover (63a) covering the opening is sealed.

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