JP4337214B2 - Cooling device for liquid-cooled internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cooling apparatus for a liquid-cooled internal combustion engine that is suitable for use in, for example, a cooling system for an on-vehicle water-cooled internal combustion engine.
[0002]
[Prior art]
Japanese Patent Laid-Open No. 8-14043 discloses an improvement in warm-up performance and heating performance at the start of a conventional liquid-cooled internal combustion engine. That is, as shown in FIG. 4, in a radiator circuit 210 that circulates coolant from the liquid-cooled internal combustion engine 100 to the radiator 200, the heating radiator 310 that uses the coolant as a heat source and the liquid-cooled internal combustion engine 100 are independent. And a pump 500 that operates, and the number of revolutions (discharge flow rate) of the pump 500 is controlled by the control means (electronic control device) 600 in accordance with the coolant temperature T detected by the water temperature sensor 620. .
[0003]
Specifically, the pump 500 is stopped at the start-up time when the coolant temperature T is low, and the pump 500 is rotated at a high speed at the warm-up promoting coolant temperature. Further, when heating is desired to be effective from a time when the coolant temperature T is relatively low (when the heater switch 340 is turned on), the pump 500 is rotated at a high speed, and the radiator circuit 320 that circulates the radiator 310 for heating is used. Control is performed so that the rotational speed of the pump 500 decreases as the coolant temperature T increases and the coolant temperature T increases.
[0004]
As a result, when the liquid-cooled internal combustion engine is started, the coolant temperature T can be quickly increased to improve the warm-up performance, and the heating performance can be improved even when the coolant temperature T is relatively low.
[0005]
[Problems to be solved by the invention]
However, in the above apparatus, the relationship between the coolant flow rate flowing through the radiator circuit 210, the bypass circuit 300 bypassing the radiator 200, and the radiator circuit 320 and the pump 500 is not considered. That is, in order to improve the warming-up performance and the heating performance, when increasing the coolant flow rate of each circuit, particularly the bypass circuit 300 or the radiator circuit 320, according to the coolant temperature T, the coolant flow rate is increased. Since the coolant flows in addition to the circuit to perform, it is necessary to rotate the pump 500 at a high speed in order to ensure the required flow rate. Therefore, power as a cooling device is consumed greatly.
[0006]
An object of the present invention is to provide a cooling apparatus for a liquid-cooled internal combustion engine that reduces the power consumption of the pump as much as possible and improves the warm-up performance and heating performance of the liquid-cooled internal combustion engine at the start. Is to provide.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention employs the following technical means.
[0008]
In the first aspect of the invention, after cooling the coolant flowing out from the liquid-cooled internal combustion engine (100), the radiator (200) that flows out the cooled coolant toward the liquid-cooled internal combustion engine (100). )When,
A bypass circuit (300) for bypassing the coolant flowing out from the liquid-cooled internal combustion engine (100) to the radiator (200) and leading to the outlet side of the radiator (200);
A heating radiator (310) that uses a coolant flowing out of the liquid-cooled internal combustion engine (100) as a heat source;
A flow rate control valve (400) for controlling the bypass flow rate (Vb) of the coolant flowing through the bypass circuit (300), the radiator flow rate (Vr) of the coolant flowing through the radiator (200), and
A pump (500) that operates independently of the liquid-cooled internal combustion engine (100) and circulates the coolant;
In a cooling apparatus for a liquid-cooled internal combustion engine having a flow control valve (400) and a control means (600) for controlling the operation of a pump (500),
The coolant outlet from the radiator (310) for heating is connected to the flow control valve (400),
The flow control valve (400) simultaneously controls the radiator flow rate (Vh) of the coolant flowing through the heating radiator (310) in addition to the bypass flow rate (Vb) and the radiator flow rate (Vr),
The control means (600) is configured such that a cooling air temperature (Tb ) of the liquid cooling internal combustion engine (100) is equal to or lower than a predetermined value and a heating air conditioner (301) having a heating radiator (310) is operated. When the flow control valve (400) is open , the radiator flow rate (Vh) is maximized, the radiator flow rate (Vr) and the bypass flow rate (Vb) are minimized, and the discharge flow rate of the pump (500) is increased. And the discharge flow rate of the pump (500) is controlled.
[0009]
In the invention according to claim 2, the control means (600) is configured such that the coolant temperature (Tb) of the liquid-cooled internal combustion engine (100) is equal to or lower than a predetermined value and the heating air conditioner (301) is activated. If so, the opening of the flow control valve (400) is controlled to fully open the circuit (320) having the heating radiator (310), and the circuit (210) having the radiator (200) and the bypass circuit (300 ) Is fully closed .
[0010]
In the invention according to claim 3, when the coolant temperature (Tb) is not more than a predetermined value and the heating air conditioner (301) is not in operation , the control means (600) mainly controls the bypass circuit ( 300), the coolant is allowed to flow, and the discharge flow rate of the pump (500) is reduced.
When the coolant temperature (Tb) is higher than the predetermined value, the flow rate control valve (400) is opened so that the coolant flows mainly through the heating radiator (310) and the discharge flow rate of the pump (500) is increased. And the discharge flow rate of the pump (500) is controlled .
[0011]
The invention according to claim 4 is characterized in that the predetermined value of the coolant temperature (Tb) is the coolant temperature at the end of warm-up after the start of the liquid-cooled internal combustion engine (100). .
[0012]
According to invention of Claims 1-4, according to the operating state of coolant temperature (Tb) and a heating air conditioner (301) by a flow control valve (400), the radiator (200), the bypass circuit ( 300), among the heating radiators (310), a circuit in which cooling liquid is to be given priority can be selected, and the cooling liquid is not allowed to flow in other circuits, so that the consumption of the pump (500) Power can be reduced.
[0013]
In particular, after starting the liquid-cooled internal combustion engine (100), the bypass circuit (300) and the heating heat dissipation are based on the coolant temperature at the end of warm-up and the operating state of the heating air conditioner (301). Since the flow rate to the vessel (310) is adjusted, warm-up performance and heating performance can be improved.
[0014]
Moreover, since the flow rate of the radiator (200), the bypass circuit (300), and the heating radiator (310) can be adjusted integrally by the flow control valve (400), the heating radiator (310 ) A dedicated flow control valve can be abolished and a cooling device can be constructed at low cost.
[0015]
In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment description mentioned later.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
In the present embodiment, the cooling device for a liquid-cooled internal combustion engine according to the present invention is applied to a water-cooled internal combustion engine for vehicle travel, and FIG. 1 is a schematic diagram of the entire cooling device.
[0017]
The radiator 200 is a heat exchanger that cools cooling water circulating in the liquid-cooled internal combustion engine (hereinafter referred to as the engine) 100, and the radiator 200 is provided with a blower 230 that blows air. In this example, the blower 230 is a type that sucks air from the radiator 200 side, and the drive motor of the blower 230 can vary the rotation speed by changing the duty as a control amount, and the output can be adjusted to adjust the blower amount. Type. As the duty increases or decreases, the power consumption of the blower 230 also increases or decreases.
[0018]
The engine 100 and the radiator 200 are connected by a radiator circuit 210 in which cooling water circulates. In addition, a bypass circuit 300 is provided that guides the cooling water flowing out from the engine 100 to the outlet side of the radiator 200 in the radiator circuit 210 by bypassing the radiator 200. A flow rate control valve 400 that controls the flow rate of cooling water flowing through the radiator 200, the bypass circuit 300, and a heating radiator 310 described later is provided at a junction 220 between the bypass circuit 300 and the radiator circuit 210. An electric pump (hereinafter referred to as a pump) 500 that operates independently of the engine 100 and circulates the cooling water is provided downstream of the flow rate control valve 400 (on the engine 100 side). Yes. Similar to the blower 230, the pump 500 is a variable output type capable of continuously varying the number of rotations by varying the duty as the control amount and adjusting the discharge flow rate. As the duty increases or decreases, the power consumption of the pump 500 also increases or decreases.
[0019]
Further, a heating air conditioner 301 having a heating radiator (hereinafter referred to as a heater) 310 and a radiator fan (hereinafter referred to as a heater blower) 330 using cooling water flowing out from the engine 100 as a heat source is provided. Yes. The cooling water flow path on the side flowing out from the heater 310 is connected to the flow control valve 400 to form a radiator circuit (hereinafter referred to as a heater circuit) 320. When the air conditioner 301 for heating is operated, the heater blower 330 is operated, and the air blown is heat-exchanged by the heater 310 to become hot air, and is sent to the vehicle interior through a duct (not shown).
[0020]
Here, the flow rate control valve 400 is provided with a valve that is opened and closed by a motor. The flow rate of cooling water flowing through the radiator 200 (hereinafter, this flow rate is referred to as the radiator flow rate Vr) and the bypass circuit 300. In addition to the flow rate of cooling water flowing through the interior (hereinafter, this flow rate is referred to as bypass flow rate Vb), the flow rate of cooling water flowing through the heater 310 (hereinafter referred to as radiator flow rate, ie, heater flow rate Vh). Is controlled by varying the valve opening. That is, the sum of the flow rates Vr, Vb, and Vh is the pump flow rate Vp discharged from the pump 500, and the pump flow rate Vp is distributed to the flow rates Vr, Vb, and Vh depending on the valve opening degree of the flow rate control valve 400. . Specifically, one of the circuits 210, 300, and 320 is fully opened, the other two circuits are fully closed, and the flow rate of the fully opened circuit is maximized (fully closed). The flow rate of the other circuits is minimized). Further, the heater circuit 320 is fixed in a fully opened state, the heater flow rate Vh is maximized, the opening degrees of the radiator circuit 210 and the bypass circuit 300 are increased and decreased, and the distribution ratio between the radiator flow rate Vr and the bypass flow rate Vb is adjusted. When the valve opening degree θ of the radiator circuit 210 (hereinafter, θ represents the opening degree of the radiator circuit 210) is 0%, the radiator flow rate Vr is minimum (bypass flow rate Vb is maximum), and the valve opening amount θ is 100. %, The radiator flow rate Vr is maximized (bypass flow rate Vb is minimized). Further, the heater circuit 320 is fixed in a fully closed state to minimize the heater flow rate Vh, and the opening degree of the radiator circuit 210 and the bypass circuit 300 is increased or decreased to adjust the distribution ratio between the radiator flow rate Vr and the bypass flow rate Vb.
[0021]
In addition, an electronic control unit (hereinafter referred to as ECU) 600 that controls the pump 500, the flow control valve 400 and the blower 230 is provided. Pressure sensor 610 (pressure detection means) for detecting Pa, rotation sensor 624 (rotation speed detection means) for detecting the rotation speed Ne of the engine 100, and outside air temperature sensor 626 (temperature detection means) for detecting the outside air temperature Ta. , A first water temperature sensor 621 (temperature detection means) for detecting the temperature of cooling water flowing into the pump 500 (hereinafter referred to as pump inlet water temperature) Tp, and the temperature of the cooling water flowing through the bypass circuit 300 (hereinafter referred to as bypass water temperature). The second water temperature sensor 622 (temperature detecting means) for detecting Tb, and the potentiometer for detecting the valve opening degree of the flow control valve 400. 424 (opening detection means), a detection signal from the heater blower 330 and an air conditioning apparatus 700 has been entered, ECU 600, based on these detection signals, controls the pump 500, the flow control valve 400 and the blower 230. Further, the ECU 600 counts the number N of readings of a target water temperature Tmap (described later) read based on detection signals from the sensors 610, 624, 626, 621, 622 and the air conditioner 700 (not shown). Z.) is provided.
[0022]
Next, the operation of the present embodiment will be described based on the flowchart shown in FIG.
[0023]
When an ignition switch (not shown) of the vehicle is turned on, power is turned on to ECU 600 and ECU 600 is activated. First, in step S50, the counter is reset and the number of readings N becomes zero. Next, in step S100, the detection signals of the sensors 610, 624, 626, 621, 622 and the air conditioner 700 are read in order to grasp the load state of the engine 100. The load of the engine 100 is detected mainly using the intake pressure Pa and the rotational speed Ne as parameters, which affect the bypass water temperature Tb and the pump inlet water temperature Tp. The larger the parameters, the greater the load on engine 100.
[0024]
In step S110, a target water temperature Tmap is read from a water temperature control map (not shown). The water temperature control map is obtained by assigning in advance target water temperature values of cooling water to be controlled in accordance with the outside air temperature Ta, the operating state of the air conditioner 700, the intake pressure Pa and the rotation speed Ne. What is the target water temperature Tmap? This means the target water temperature value. For example, as the intake pressure Pa is higher (the throttle valve opening of the engine 100 is larger) and the rotational speed Ne is larger, the load of the engine 100 is higher, and the target water temperature Tmap is set to a lower value. When the intake pressure Pa is low (throttle valve opening is small) and the rotational speed Ne is small, the load on the engine 100 is low, so the target water temperature Tmap is set to a higher value.
[0025]
In step S112, the number N of reads of the target water temperature Tmap is set to N + 1. In subsequent step S115, it is determined whether or not the number of readings N is 1. If N is 1, it is determined that the engine 100 has just started, and the process proceeds to step S118. If NO is determined, the process proceeds to step S120 because the process in step S118 described later is unnecessary.
[0026]
In step S118, the basic duty of the pump 500 and the basic valve opening of the flow control valve 400 are determined as initial values from a map (not shown), the pump 500 is operated, and the valve of the flow control valve 400 is opened. As the duty of the pump 500 increases, the pump rotation speed increases, the flow rate of the cooling water flowing through each circuit 210, 300, 320 increases, and the power consumption of the pump 500 itself increases. Moreover, the flow rate which flows through the circuit increases, so that the valve opening degree of the flow control valve 400 is large.
[0027]
In step S120, it is determined whether or not the bypass water temperature Tb detected by the water temperature sensor 622 is lower than the warm-up end water temperature Tw1, and if it is lower, the process proceeds to step S130. Incidentally, the warm-up end water temperature Tw1 is decreased by the frictional loss of the operating portion of the engine 100 due to the rise of the cooling water temperature, the lubricating oil temperature in the engine 100, etc. after the engine 100 is started. The temperature of the cooling water at which the engine 100 operates stably is set as a value around 80 degrees C in this embodiment.
[0028]
In step S130, it is determined whether or not the heater blower 330 is operating. If it is determined that the heater blower 330 is not operating, the process proceeds to step S160 and warm-up priority control is performed. That is, in order to increase the coolant temperature quickly, the valve opening degree of the flow rate control valve 400 is controlled so that the bypass circuit 300 is fully opened, and the radiator circuit 210 and the heater circuit 320 are fully closed. The duty is controlled to be lower than the basic duty set in step S118, and low-flow cooling water is circulated only in the bypass circuit 300.
[0029]
However, if the heater blower 330 is operating in step S130 (when the occupant operates the heating air conditioner 301 from an early stage after starting the engine 100), the process proceeds to step S140 to perform heater priority control. That is, in order to make the heating air conditioner 301 work more efficiently, the valve of the flow control valve 400 is controlled so that the heater circuit 320 is fully opened, and the radiator circuit 210 and the bypass circuit 300 are fully closed. In S150, the duty of the pump 400 is controlled to be higher than the basic duty set in Step S118, and a high flow rate of cooling water is circulated only in the heater circuit 320.
[0030]
If the bypass water temperature Tb exceeds the warm-up end water temperature Tw1 in step S120 and becomes higher, it is further determined in step S180 whether or not it is lower than the target water temperature Tmap, and if it is lower, the process proceeds to step S140 and the heater priority control is performed. I do.
[0031]
If it is determined NO in step S180, in step S190, the pump inlet water temperature Tp is within a predetermined range based on the target water temperature Tmap (in this embodiment, a range of ± 2 degrees with respect to the target water temperature). If the pump inlet water temperature Tp is within the predetermined range, the process proceeds to step S200, and the pump duty and valve opening set in step S118 or steps S220, S240, S250, and S270 described later are maintained. The
[0032]
When the pump inlet water temperature Tp is not within the predetermined range in step S190, the process proceeds to step S210 in order to optimize the cooling capacity of the cooling device and adjust the pump inlet water temperature Tp to the target water temperature Tmap.
[0033]
In step S210, it is further determined whether or not the pump inlet water temperature Tp is higher than the target water temperature Tmap. If higher, in step S220, first, in order to lower the pump inlet water temperature Tp without increasing the power consumption of the cooling device, The flow control valve 400 is preferentially operated to increase the valve opening degree θ of the radiator circuit 210 by a predetermined amount. As a result, the radiator flow rate Vr is increased, and the heat dissipation capability of the radiator 200 is increased to lower the pump inlet water temperature Tp. In step S230, it is determined whether or not the valve opening θ is 100%. If it has reached 100%, in step S240, the duty of the pump 500 is changed by a predetermined amount to change the rotational speed of the pump 500. In this case, in order to lower the pump inlet water temperature Tp, the duty of the pump 500 is increased and the pump rotational speed is increased to increase the discharge flow rate. If the valve opening degree θ does not reach 100% in step S230, the valve opening degree θ opened in step S220 is maintained.
[0034]
On the other hand, if it is determined in step S210 that the pump inlet water temperature Tp is lower than the target water temperature Tmap, the process proceeds to step S250, and first, the pump 500 is preferentially operated so that less power is consumed by the cooling device. The duty is changed by a predetermined amount, and the rotational speed of the pump 500 is changed. In this case, in order to raise the pump inlet water temperature Tp, the duty of the pump 500 is lowered and the pump rotation speed is lowered to reduce the discharge flow rate. In step S260, it is determined whether or not the duty of the pump 500 has reached the minimum value. If the minimum value has been reached, the valve opening θ of the flow control valve 400 is further decreased by a predetermined amount in step S270, and the radiator The pump inlet water temperature Tp is raised by decreasing the flow rate Vr and lowering the heat dissipation capability of the radiator 200. If the duty of the pump 500 has not reached the minimum value in step S260, the duty of the pump 500 controlled in step S250 is maintained. Steps S230, S240, S260, and S270 are feedback controlled so that the pump inlet water temperature Tp converges to the target water temperature Tmap by repeating the return to step S100.
[0035]
In steps S150, S170, S200, S240, and S250 in the above flowchart, the air flow of the blower 230 is determined and operated so that the power consumption of the pump 500 and the blower 230 is minimized.
[0036]
With the above configuration and operation, the flow control valve 400 can select a circuit in which the cooling water is to flow preferentially in the heater 310 in addition to the radiator 200 and the bypass circuit 300 according to the bypass water temperature Tb and the pump inlet water temperature Tp. Since the cooling water is prevented from flowing through the other circuits, the power consumption of the pump 500 can be reduced.
[0037]
And the warming-up performance and heating performance at the time of starting of the engine 100 can be improved. Specifically, as shown in FIG. 3 (indicating the flow rate in the circuit and the cooling water temperature on the outlet side of the engine 100), in the warm-up priority control (part A), a low flow rate (Vb of the prior art) Since the cooling water of Vb) is circulated with respect to ', the power consumption of the pump 500 can be reduced. And since the rise of the wall temperature of the engine 100 becomes faster and the temperature difference with the cooling water becomes larger, the temperature rise time of the cooling water is shortened and the warm-up performance is improved. When the time to reach the stoichiometric water temperature at which the engine 100 can be operated at the stoichiometric air-fuel ratio (around 60 degrees C in this embodiment) is compared between the present invention and the prior art, ΔT can be shortened and the fuel efficiency of the engine 100 can be improved. It can be improved. In the heater priority control (B section), the cooling water is circulated in the bypass circuit 300 and the heater circuit 320 in the conventional technique, whereas the high flow rate (Vb ″ + Vh in the conventional technique is increased) only in the heater circuit 320. On the other hand, since the cooling water (only Vh) is circulated, the work of the pump 500 can be concentrated in the heater circuit 320, and the heating performance can be improved with the minimum necessary power consumption.
[0038]
In addition, since the blower 230 is operated in combination with the pump 500 like the flow control valve 400, the power consumption of the pump 500 can be further reduced.
[0039]
Furthermore, since the flow rate adjustment function of the radiator 200, the bypass circuit 300, and the heater 310 is integrally provided by the flow rate control valve 400, the flow rate adjustment valve dedicated to the heater 310 can be eliminated and a cooling device can be configured at low cost.
[0040]
In this embodiment, the intake pressure Pa and the rotational speed Ne are used as parameters for detecting the load of the engine 100. However, the engine state and the running state of the vehicle that affect the coolant temperature Tp and Tb are shown. For example, parameters such as the vehicle speed Vv, the throttle valve opening of the engine 100, and the intake air amount can be used.
[0041]
In the present embodiment, the configuration has been described on the assumption that the electric pump is used. However, the same effect can be obtained with a hydraulic pump.
[Brief description of the drawings]
FIG. 1 is a schematic view of an entire cooling device showing an embodiment of the present invention.
FIG. 2 is a control flowchart of a cooling device.
FIG. 3 is a graph showing a comparison of cooling water temperature between the present invention and the prior art.
FIG. 4 is a schematic diagram of the entire cooling device showing the prior art.
[Explanation of symbols]
100 engine (liquid-cooled internal combustion engine)
200 Radiator 210 Radiator Circuit 220 Merging Port 230 Blower 300 Bypass Circuit 301 Heating Air Conditioner 310 Heater (Heating Radiator)
320 Heater circuit (heatsink circuit)
330 Heater blower (radiator blower)
400 Flow control valve 424 Potentiometer 500 Electric pump (pump)
600 ECU (electronic control unit)
610 Pressure sensor 621 First water temperature sensor 622 Second water temperature sensor 624 Rotation sensor 626 Outside air temperature sensor 700 Air conditioner

Claims (4)

A radiator (200) that cools the coolant flowing out from the liquid-cooled internal combustion engine (100) and then flows the cooled coolant toward the liquid-cooled internal combustion engine (100);
A bypass circuit (300) for bypassing the coolant flowing out from the liquid-cooled internal combustion engine (100) to the radiator (200) and leading to the outlet of the radiator (200);
A heating radiator (310) that uses a coolant flowing out of the liquid-cooled internal combustion engine (100) as a heat source;
A flow rate control valve (400) for controlling the bypass flow rate (Vb) of the coolant flowing through the bypass circuit (300), the radiator flow rate (Vr) of the coolant flowing through the radiator (200), and
A pump (500) that operates independently of the liquid-cooled internal combustion engine (100) and circulates a coolant;
In a cooling apparatus for a liquid-cooled internal combustion engine, comprising a flow rate control valve (400) and a control means (600) for controlling the operation of the pump (500).
A coolant outlet from the heating radiator (310) is connected to the flow control valve (400);
The flow control valve (400) simultaneously controls the radiator flow rate (Vh) of the coolant flowing through the heating radiator (310) in addition to the bypass flow rate (Vb) and the radiator flow rate (Vr). ,
The control means (600) includes a heating air conditioner (301) having a cooling liquid temperature (Tb) of the liquid-cooled internal combustion engine (100) equal to or lower than a predetermined value and having the heating radiator (310). When operating, the radiator flow rate (Vh) is maximized, the radiator flow rate (Vr) and the bypass flow rate (Vb) are minimized, and the discharge flow rate of the pump (500) is increased. A cooling device for a liquid-cooled internal combustion engine, wherein the opening degree of the flow control valve (400) and the discharge flow rate of the pump (500) are controlled. When the coolant temperature (Tb) of the liquid-cooled internal combustion engine (100) is equal to or lower than a predetermined value and the heating air conditioner (301) is operating, the control means (600) By controlling the opening degree of the control valve (400), the circuit (320) having the heating radiator (310) is fully opened, and the circuit (210) having the radiator (200) and the bypass circuit (300) are 2. The cooling device for a liquid-cooled internal combustion engine according to claim 1, wherein the cooling device is fully closed . When the coolant temperature (Tb) is not more than a predetermined value and the heating air conditioner (301) is not operating, the control means (600) mainly supplies coolant to the bypass circuit (300). In order to reduce the discharge flow rate of the pump (500),
When the coolant temperature (Tb) is higher than the predetermined value, the flow rate control valve is configured so that the coolant flows mainly through the heating radiator (310) and the discharge flow rate of the pump (500) is increased. The cooling device for a liquid-cooled internal combustion engine according to claim 1 or 2 , wherein the opening degree of (400) and the discharge flow rate of said pump (500) are controlled. Any predetermined value of the coolant temperature (Tb) and the of claims 1 to 3, wherein the liquid is a coolant temperature during the warm-up completion after the start of the cooled internal combustion engine (100) A cooling apparatus for a liquid-cooled internal combustion engine according to claim 1.

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