JP6922718B2 - Power storage device cooling system - Google Patents

Description

The present disclosure relates to a cooling system for a power storage device, and more specifically to a cooling system for cooling a power storage device mounted on a hybrid vehicle.

In recent years, hybrid vehicles equipped with power storage devices have become widespread. When the temperature of the power storage device rises excessively, the charge / discharge performance of the power storage device deteriorates and the deterioration rate of the power storage device increases. Therefore, in general, a cooling system is provided in the power storage device in the vehicle. In many hybrid vehicles, a power storage device is installed in a luggage room (luggage room) at the rear of the vehicle, and various technologies for cooling such the power storage device have been proposed.

For example, in FIG. 1 of Japanese Patent Application Laid-Open No. 2016-117366 (Patent Document 1), in a cooling system of a power storage device applied to a vehicle in which a power storage device is mounted in a luggage room, a cabin (vehicle compartment) and a power storage device are shown. A configuration is disclosed in which a duct for communicating, a blower provided in the duct for sucking air in the cabin and sending it to a power storage device, and a communication port for returning the air after cooling the power storage device to the inside of the cabin are provided. ing. In this configuration, the air in the cabin is taken in by the blower to cool the power storage device. The air after cooling the power storage device is exhausted into the luggage room, and a part of the air returns to the cabin through the communication port.

Japanese Unexamined Patent Publication No. 2016-117366

Under conditions where the outside air temperature is low, such as in winter, the interior of the vehicle can be cooled by the outside air and become cold. In particular, in the cooling system having the above configuration, the air returning from the luggage room to the cabin flows along the rear glass. Therefore, the air (cold air) that has become cold due to heat exchange with the outside air in the rear glass may reach the user sitting in the rear seat and cause discomfort to the user.

As a measure for suppressing the deterioration of the user's comfort, it is conceivable to reduce the intake amount of the blower when the predetermined condition is satisfied as compared with the case where the predetermined condition is not satisfied. By reducing the intake amount of the blower, the cold air reaching the user is reduced, so that the user's discomfort can be suppressed.

Although the details will be described later, since the user may be uncomfortable when the intake air temperature of the blower is low, an intake air temperature sensor is provided in the duct to detect that the intake air temperature is low as the above-mentioned predetermined condition. Can be considered. Further, since the outside air temperature of the hybrid vehicle can affect the intake air temperature, it is conceivable to provide an outside air temperature sensor to detect the outside air temperature.

However, if the intake air temperature sensor or the outside air temperature sensor is provided, an extra member cost will be incurred. In addition, since an abnormality such as a failure may occur in the intake air temperature sensor or the outside air temperature sensor, it is necessary to take measures against it, which is complicated. Therefore, without providing an intake air temperature sensor and an outside air temperature sensor, the intake amount of the blower is appropriately suppressed to suppress the discomfort of the user, and the intake amount of the blower is secured as necessary to appropriately operate the power storage device. It is desirable to cool.

The present disclosure has been made to solve the above problems, and an object of the present invention is to provide an intake air temperature sensor and an outside air temperature sensor in a cooling system of a power storage device for cooling a power storage device mounted on a vehicle. Instead, it is to provide a technology capable of appropriately cooling the power storage device while suppressing the discomfort of the user.

A power storage device cooling system according to an aspect of the present disclosure cools a power storage device mounted on a hybrid vehicle equipped with an engine. The cooling system of the power storage device includes a temperature sensor that detects the cooling water temperature of the engine, a duct that connects the passenger compartment and the power storage device, and a blower that is provided in the duct and takes in the air in the vehicle interior and sends it to the power storage device. It is provided near the rear glass and is provided with a communication port for returning the air after cooling the power storage device to the vehicle interior and a control device. When the elapsed time from the start of the system of the hybrid vehicle is shorter than the reference time, the control device controls the blower so as to reduce the intake amount of the blower as compared with the case where the elapsed time is longer than the reference time. .. The control device estimates the outside air temperature of the hybrid vehicle from the detected value of the temperature sensor when the stop period between the previous system stop and the current system start is longer than a predetermined period. The control device sets the reference time so that the higher the estimated outside air temperature is, the shorter the reference time is, and the shorter the stop period is, the shorter the reference time is.

Even if the cooling water temperature of the engine rises while the hybrid vehicle is running, if the stop period is longer than the predetermined period, the cooling water temperature drops to a temperature close to the outside air temperature due to heat dissipation from the cooling water. It is thought that it is. Therefore, it is possible to estimate the outside air temperature of the hybrid vehicle from the detected value of the temperature sensor.

When the stop period is short, not much time has passed since the system of the hybrid vehicle was stopped, so the temperature inside the vehicle (≈ blower intake temperature) that was warmed during the previous run is maintained at a relatively high temperature. There is a high possibility that it is. Further, even when the outside air temperature is relatively high, the temperature inside the vehicle interior is relatively high. Therefore, according to the above configuration, the shorter the stop period and the higher the outside air temperature, the shorter the reference time is set. As a result, the intake amount of the blower increases at an early stage, but since the intake temperature of the blower is high, it is unlikely to cause discomfort to the user. On the other hand, by increasing the intake amount of the blower at an early stage, the power storage device can be appropriately cooled. Therefore, according to the above configuration, the power storage device can be appropriately cooled while suppressing the discomfort of the user without providing the intake air temperature sensor and the outside air temperature sensor.

According to the present disclosure, it is possible to appropriately cool the power storage device while suppressing the discomfort of the user without providing the intake air temperature sensor and the outside air temperature sensor.

It is a figure which shows schematic the whole structure of the vehicle which mounted the cooling system of the battery pack which concerns on this embodiment. It is a figure which shows schematic structure of the cooling system of a battery pack. It is a figure which shows the relationship between the IG-OFF time and the intake air temperature according to the outside air temperature. It is a flowchart for demonstrating the cooling control of a battery pack in this embodiment. It is a figure for demonstrating an example of a map MP.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals, and the description thereof will not be repeated.

[Embodiment]
<Overall configuration of hybrid vehicle>
FIG. 1 is a diagram schematically showing an overall configuration of a vehicle equipped with a battery pack cooling system according to the present embodiment. With reference to FIG. 1, vehicle 1 is a hybrid vehicle (including a plug-in hybrid vehicle).

A front seat 21 and a rear seat 22 are arranged in the cabin (cabin) 2 of the vehicle 1. An engine compartment 3 is provided in front of the cabin 2. A luggage room 4 is provided behind the cabin 2. The vehicle 1 includes an engine 31, an air conditioner 32, and a motor generator (not shown) mounted in the engine compartment 3, and a battery pack 41 mounted in the luggage room 4. The battery pack 41 is provided with a cooling system 10.

The engine 31 is an internal combustion engine such as a gasoline engine or a diesel engine. The engine 31 outputs power by converting the combustion energy generated when the air-fuel mixture is burned into kinetic energy.

The air conditioner 32 is driven by electric power from the battery pack 41, and cools or heats the inside of the cabin 2 according to a control signal from the ECU 100 (see FIG. 2).

The battery pack 41 supplies electric power for generating the driving force of the vehicle 1 to the driving device of the motor generator (neither of them is shown). The battery pack 41 can also store the electric power generated by the motor generator.

<Battery pack cooling system configuration>
FIG. 2 is a diagram schematically showing the configuration of the cooling system 10 of the battery pack 41. With reference to FIG. 2, a package tray 5 for partitioning the cabin 2 and the luggage room 4 is provided above the rear side of the rear seat 22 arranged in the cabin 2. A rear glass 6 is provided above the package tray 5.

The battery pack 41 includes an assembled battery (not shown) including a plurality of cells, a battery temperature sensor 411, and a battery case (not shown) for accommodating the assembled battery. On the rear side of the battery pack 41, an exhaust port 412 for exhausting the air cooled by the assembled battery in the battery pack 41 to the luggage room 4 is provided.

Each cell constituting the assembled battery is typically a secondary battery such as a nickel hydrogen battery or a lithium ion secondary battery. However, each cell may be a capacitor such as an electric double layer capacitor. The battery pack 41 corresponds to the "power storage device" according to the present disclosure.

The battery temperature sensor 411 detects the temperature (hereinafter, also referred to as “battery temperature”) TB of the assembled battery, and outputs the detection result to the ECU 100.

The cooling system 10 of the battery pack 41 includes an intake duct 11, a blower 12, a communication port 13, an engine water temperature sensor 14 (see FIG. 1), and an ECU 100.

One end of the intake duct 11 is open to the cabin 2, and the other end of the intake duct 11 is connected to the battery pack 41. That is, the intake duct 11 communicates the cabin 2 with the battery pack 41.

The blower 12 is provided in the intake duct 11. The blower 12 takes in the air in the cabin 2 and sends the air (cooling air) to the assembled battery (not shown) in the battery pack 41.

The communication port 13 is provided in the package tray 5 and communicates the cabin 2 and the luggage room 4. The number of communication ports 13 is not particularly limited, and may be one or a plurality.

The engine water temperature sensor 14 is provided in a flow path (not shown) of cooling water of the engine 31. The engine water temperature sensor 14 detects the temperature of the cooling water of the engine 31 (hereinafter, also referred to as “engine water temperature”) TW, and outputs the detection result to the ECU 100.

Although not shown, the ECU 100 includes a CPU (Central Processing Unit), a memory, a buffer, and a timer. The ECU 100 controls each device so that the vehicle 1 is in a desired state based on the detection value of each sensor and the program stored in the memory. The main control executed by the ECU 100 in the present embodiment is the control of the blower 12. This blower control will be described in detail below.

<Blower control>
When the blower 12 is driven, the air in the cabin 2 is sent to the battery pack 41 via the intake duct 11 (see arrow AIR1). Then, the air sent to the battery pack 41 exchanges heat with the assembled battery (not shown) to cool the assembled battery. The air after heat exchange is discharged from the exhaust port 412 to the luggage room 4 behind the battery pack 41 (see arrow AIR2). The air in the luggage room 4 is pushed out from the communication port 13 provided in the package tray 5 by the air discharged from the exhaust port 412 and flows into the cabin 2 (see arrow AIR3).

The air returning from the luggage room 4 to the cabin 2 flows along the rear glass 6 as shown by the arrow AIR3. When the outside air temperature is low (for example, below freezing point) such as in winter, the rear glass 6 may be cooled by the outside air to a low temperature. In such a case, the air (cold air) that has become cold due to heat exchange with the outside air in the rear glass 6 reaches the user sitting in the rear seat 22. As a result, it may cause discomfort to the user.

As a measure for suppressing such discomfort, when the intake air temperature Tin from the cabin 2 is lower than the predetermined temperature, the intake amount of the blower 12 is reduced as compared with the case where the intake air temperature Tin is equal to or higher than the predetermined temperature. Can be considered. The intake air temperature Tin can be detected by providing an intake air temperature sensor (not shown) in the intake air passage (any place of the intake duct 11) (for example, the intake air temperature sensor described in FIG. 2 of Patent Document 1). 26).

However, if such an intake air temperature sensor is provided, an extra member cost will be incurred. In addition, since an abnormality of the intake air temperature sensor may occur, it is necessary to take measures against it. More specifically, depending on the regulations to be observed (such as national regulations), it may be required to detect the abnormality of the intake air temperature sensor. However, it is difficult to achieve the required detection accuracy and detection frequency and satisfy the regulation without incurring excessive costs such as duplicating the intake air temperature sensor. Therefore, it is desirable to control the intake air amount of the blower 12 without providing the intake air temperature sensor so as not to cause discomfort to the user.

<Effect of outside temperature>
Here, the present inventor has focused on the fact that the outside air temperature TA of the vehicle 1 can affect the intake air temperature Tin.

FIG. 3 is a diagram showing the relationship between the IG-OFF time Δtoff and the intake air temperature Tin according to the outside air temperature TA. In FIG. 3, the horizontal axis indicates the IG-OFF time Δt _OFF . The IG-OFF time Δt _OFF is the elapsed time since the electric system of the vehicle 1 was stopped (ignition off: IG-OFF) in the previous running (trip), and corresponds to the “stop time” according to the present disclosure. do. The vertical axis indicates the intake air temperature Tin. _{In FIG. 3, how much the intake air temperature Tin decreases with the passage of the IG-OFF time Δt OFF} from the state of room temperature (25 ° C.) is shown for each outside air temperature TA.

With reference to FIG. 3, when the IG-OFF time Δt _OFF is relatively short, the cooling inside the cabin 2 by heat exchange with the outside air has not progressed so much, and the intake air temperature Tin is also maintained at a relatively high state. Has been done. After that, as the IG-OFF period Δt _OFF becomes longer, the inside of the cabin 2 is cooled and the intake air temperature Tin decreases. Further, when the outside air temperature TA is low such as below freezing point, the intake air temperature Tin decreases rapidly, but the higher the outside air temperature TA, the more gradual the decrease in the intake air temperature Tin.

It is also conceivable to control the intake amount of the blower 12 based only on _{the IG-OFF time Δt OFF} without considering the outside air temperature TA in particular. As an example, when giving priority to suppressing user discomfort, it is assumed that the outside air temperature TA is extremely low (for example, TA = −32 ° C. as shown in FIG. 3), and the blower is used. It is also conceivable to maintain the state in which the intake amount of 12 is reduced for a long time. However, in that case, when the outside air temperature TA is actually high (for example, when the temperature is 0 ° C. or higher), the cooling capacity of the battery pack 41 is excessively lowered as the intake amount of the blower 12 is reduced. As a result, the charge / discharge performance of the assembled battery may decrease or the deterioration rate of the assembled battery may increase.

In view of such circumstances, it is conceivable to provide an outside air temperature sensor (not shown) in order to reflect the outside air temperature TA in the intake air amount control of the blower 12. However, as with the intake air temperature sensor, if the outside air temperature sensor is installed, an extra member cost will be incurred, and measures will be required to prepare for the occurrence of the abnormality. Therefore, it is desirable to reflect the outside air temperature TA in the intake air amount control of the blower 12 without providing the outside air temperature sensor.

Therefore, in the present embodiment, a configuration is adopted in which the outside air temperature TA is estimated based on the engine water temperature TW that can be detected by the engine water temperature sensor 14, and the intake air amount of the blower 12 is controlled using the estimated outside air temperature TA. do. This control will be described in detail below.

<Battery pack cooling control flow>
FIG. 4 is a flowchart for explaining the cooling control of the battery pack 41 according to the present embodiment. This flowchart is called and executed from the main routine after the system is started (ignition on: IG-ON) of the vehicle 1, for example, every time a predetermined calculation cycle elapses. Each step of this flowchart (hereinafter abbreviated as "S") is basically realized by software processing by the ECU 100, but may be realized by hardware (electronic circuit) manufactured in the ECU 100. ..

It is assumed that the ECU 100 counts the _{IG-OFF time Δt OFF} by using a timer (not shown) in another routine (not shown), for example.

In S1, the ECU 100 acquires the battery temperature TB from the battery temperature sensor 411 provided in the battery pack 41.

In S2, the ECU 100 determines whether or not the battery temperature TB is equal to or higher than a predetermined determination temperature. The determination temperature is a temperature predetermined by an experiment or a simulation so that the charge / discharge performance of the battery pack 41 does not deteriorate or the deterioration rate of the battery pack 41 does not become excessively high. The determination temperature is stored in the memory (not shown) of the ECU 100. When the battery temperature TB is lower than the determination temperature (NO in S2), the ECU 100 proceeds to S10 assuming that the battery pack 41 does not need to be cooled in particular, and stops the blower 12. If the blower 12 has already stopped, the stopped state of the blower 12 is maintained.

On the other hand, for example, when the vehicle 1 is a plug-in hybrid vehicle, the battery temperature TB may become higher than the determination temperature after charging the battery pack 41 with electric power supplied from the outside of the vehicle (so-called plug-in charging). When the battery temperature TB is equal to or higher than the determination temperature (YES in S2), the ECU 100 determines that the battery pack 41 needs to be cooled. _{Then, the ECU 100 acquires the IG-OFF time Δt OFF} counted in the above-mentioned separate routine (S3).

In S4, the ECU 100 _{determines whether or not the IG-OFF time Δt OFF} is equal to or greater than the threshold value TH. The threshold value TH is a relaxation time (for example, 6 hours) required for the engine water temperature TW, which has risen while the vehicle 1 is running, to drop to a certain degree close to the outside air temperature TA due to heat dissipation of the cooling water of the engine 31. Can be predetermined. The threshold value TH is also stored in the memory of the ECU 100. The threshold TH corresponds to the "predetermined period" according to the present disclosure.

When the IG-OFF time Δt _OFF is equal to or greater than the threshold value TH (YES in S4), the ECU 100 acquires the engine water temperature TW from the engine water temperature sensor 14 (S5). Then, the ECU 100 estimates the outside air temperature TA based on the engine water temperature TW (S6). More specifically, when the current calculation cycle is the n (n is a natural number) th cycle, the outside air temperature TA (n) in the current calculation cycle is the outside air temperature TA (n-1) in the previous calculation cycle. ) And the engine water temperature TW acquired in S5, can be estimated according to the following equation (1).
TA (n) = α × TA (n-1) + (1-α) × TW ・ ・ ・ (1)

In the formula (1), α is an internal division ratio greater than 0 and less than 1 (for example, α = 0.9), and is a constant obtained in advance in a conforming manner. The initial value TA (0) of the outside air temperature TA is predetermined to be an appropriate value (for example, 25 ° C., which is room temperature).

When the IG-OFF time Δt _OFF is shorter than the threshold value TH in S4 (NO in S4), the increased engine water temperature TW still remains high, and it is highly possible that the correlation with the outside air temperature TA is low. Therefore, the ECU 100 skips the processing after S5 and returns the processing to the main routine.

However, since the engine 31 is provided in the engine compartment 3 suitable for heat dissipation, when a long period of time elapses after IG-OFF and the IG-OFF time Δt _OFF becomes the threshold TH or more, the engine is cooled by the outside air. The water temperature TW decreases. On the other hand, since the cabin 2 has improved heat insulating properties, the temperature inside the cabin 2 does not drop to the outside air temperature TA even if the IG-OFF time ΔtOFF becomes equal to or higher than the threshold value TH.

In S7, the ECU 100 calculates the _{reference time t REF.} The reference time t _REF is a time required for the temperature in the cabin 2 to become sufficiently high due to heating of the air conditioner 32 or the like, for example, a time of several tens of seconds to several tens of minutes. As described below, the ECU 100 calculates the _{reference time t REF from the IG-OFF time Δt OFF} and the outside air temperature TA by referring to the map MP stored in the memory (not shown).

FIG. 5 is a diagram for explaining an example of the map MP. In FIG. 5, the horizontal axis represents the IG-OFF time Δt _OFF , and the vertical axis represents the reference time t _REF . In the map MP, the correlation between the _{IG-OFF time Δt OFF} and the reference time t _REF is determined for each outside air temperature TA based on the results of prior experiments or simulations.

In the map MP, as shown in FIG. 5, the _{longer the IG-OFF time Δt OFF} , the longer the reference time t _REF . Further, when compared with the same IG-OFF time Δt _OFF , the lower the outside air temperature TA, the longer the _{reference time t REF.} By referring to such a map MP, the _{reference time t REF} can be calculated _{from the IG-OFF time Δt OFF} and the outside air temperature TA.

The numerical value of the outside air temperature TA shown in FIG. 5 is only an example. _{Further, in order to avoid complicating the drawings, FIG. 5 shows the correlation between the IG-OFF time Δt OFF} and the reference time t _REF at intervals of the outside air temperature TA of about 10 ° C., but the temperature is narrower. The correlation may be defined at intervals. Here, an example using the map MP will be described, but a relational expression or a function may be used instead of the map MP.

Returning to FIG. 4, in S8, the ECU 100 uses a timer (not shown) to acquire the elapsed time Δt from the time when the vehicle 1 is IG-ON. Then, the ECU 100 compares the elapsed time Δt with the reference time t _REF calculated in S8 (S9).

When the elapsed time Δt is _{less than the reference time t REF} , that is, when a certain amount of time (for example, several tens of seconds to several tens of minutes) has not passed since the time of IG-ON (NO in S9), the user Is not yet operating the air conditioner 32, or even if the user is operating the air conditioner 32, it is considered that the inside of the cabin 2 is not sufficiently warmed up. Therefore, the intake air temperature of the blower 12 is likely to be low. Therefore, the ECU 100 advances the process to S11 and drives the blower 12 (or maintains the driving state of the blower 12), but sets the intake amount of the blower 12 to IN2, which is lower than the normal amount IN1 (IN2 <IN1). ). After the processing of S11 is completed, the processing is returned to the main routine, and a series of processing is repeated at predetermined calculation cycles.

After that, when the elapsed time Δt becomes equal to _{or greater than the reference time t REF} , that is, when a certain amount of time elapses from the time of IG-ON (YES in S9), the user can use the cabin 2 even if the temperature inside the cabin 2 is low during IG-ON. It is considered that the air conditioner 32 is operated, thereby warming the inside of the cabin 2. As a result, the intake air temperature of the blower 12 may also be high to some extent. Therefore, the ECU 100 advances the process to S12, and while maintaining the blower 12 in the driving state, increases the intake amount of the blower 12 to the normal amount IN1.

As described above, according to the present embodiment, the _{reference time t REF} is calculated by using the map MP (see FIG. 5) including the two parameters of _{the IG-OFF time Δt OFF and the outside air temperature TA.} According to the map MP, the _{shorter the IG-OFF time Δt OFF} , the shorter the reference time t _REF is calculated. Further, when the outside air temperature TA is high (for example, when the temperature is 0 ° C. or higher), the reference time t _REF is shorter than when the outside air temperature TA is low (for example, when the temperature is below freezing point).

More specifically, when the IG-OFF time Δt _OFF is short, not much time has passed since the IG-OFF operation of the vehicle 1 was performed, so that the inside of the cabin 2 that was warmed during the previous run was used. It is highly possible that the temperature (in other words, the intake air temperature Tin of the blower 12) is maintained at a relatively high temperature. Further, even when the outside air temperature TA is high, the temperature inside the cabin 2 is relatively high. Therefore, according to the present embodiment, the _{shorter the IG-OFF time Δt OFF} and the higher the outside air temperature TA, the _{shorter the reference time t REF} is set. As a result, the intake amount of the blower 12 increases from the low amount IN2 to the normal amount IN1 at an early stage, but since the intake temperature Tin is high, it is unlikely to cause discomfort to the user. On the other hand, by increasing the intake amount of the blower 12 at an early stage, the battery pack 41 can be appropriately cooled.

_{In this way, by calculating the reference time t REF} in consideration of both the IG-OFF time Δt _OFF and the outside air temperature TA, the battery pack 41 can be appropriately cooled while suppressing the discomfort of the user. ..

It was explained that when the IG-OFF time ΔtOFF is shorter than the threshold value TH in S4 (NO in S4), the subsequent processing is skipped and the processing is returned to the main routine. However, in this case, although the outside air temperature TA is not estimated, the reference time t _REF may be calculated _{from the IG-OFF time Δt OFF.} For example, the reference time t _REF can be calculated _{from the IG-OFF time Δt OFF} by referring to a map (not shown) that does not depend on the outside air temperature TA unlike the map MP shown in FIG. can.

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The scope of the present disclosure is indicated by the scope of claims rather than the description of the embodiment described above, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 vehicle, 2 cabins, 21 front seats, 22 rear seats, 3 engine compartments, 31 engines, 32 air conditioners, 4 luggage rooms, 41 battery packs, 411 battery temperature sensors, 412 exhaust ports, 5 package trays, 6 rear glasses, 10 cooling system, 11 intake duct, 12 blower, 13 communication port, 14 engine water temperature sensor, 100 ECU.

Claims (1)

A power storage device cooling system that cools the power storage device mounted on a hybrid vehicle equipped with an engine.
A temperature sensor that detects the cooling water temperature of the engine and
A duct that connects the passenger compartment and the power storage device,
A blower provided in the duct, which takes in the air in the vehicle interior and sends it to the power storage device,
A communication port provided near the rear glass for returning the air after cooling the power storage device to the passenger compartment, and
When the elapsed time from the start of the system of the hybrid vehicle is shorter than the reference time, the blower is controlled so as to reduce the intake amount of the blower as compared with the case where the elapsed time is longer than the reference time. Equipped with a control device
The control device estimates the outside air temperature of the hybrid vehicle from the detection value of the temperature sensor when the stop period between the previous system stop and the current system start is longer than a predetermined period. A cooling system for a power storage device that sets the reference time so that the higher the outside air temperature, the shorter the reference time, and the shorter the stop period, the shorter the reference time.

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