KR20200013869A - Method for Improving Fuel Efficiency Based On Air Conditioning Load On Eco Friendly Vehicle - Google Patents

Abstract

A control method for improving fuel efficiency by an electric field load classification method in an eco-friendly vehicle of the present invention corrects the power consumption of an auxiliary electric field load detected in an auto mode, and controls the auto mode in a state in which the set value of engine start reference power is lowered by using the linearity of the power consumption of the auxiliary electric field load to greatly improve engine utilization against the auto mode in which the set value is maintained, thereby improving fuel efficiency when driving at medium and long distances longer than all electric range.

Description

Method for Improving Fuel Efficiency Based On Air Conditioning Load On Eco Friendly Vehicle}

The present invention relates to fuel efficiency improvement control of an environment-friendly vehicle, and more particularly, to a control method of improving fuel efficiency based on an air-conditioning vehicle that can improve fuel efficiency by improving control efficiency of an auto mode.

In general, a plug-in hybrid electric vehicle (PHEV) among environmentally friendly vehicles may have various advantages by greatly improving battery capacity and performance.

Therefore, since the PHEV can be driven only by charging the battery using an external power source when driving at a short distance compared to a long distance driving using an internal combustion engine, it is possible to implement a manual that can operate a substantial portion of the vehicle driving using only the electric energy of the battery. In hybrid vehicles (electric vehicles) or electric vehicles (electric vehicles) of the battery overcomes the limitation that was applied only as a power source in the low / low torque range.

In addition, the PHEV can realize a variety of control in the auto mode by utilizing a high degree of freedom in terms of fuel efficiency control compared to a hybrid vehicle with a large battery capacity.

For example, in the case of implementing control variability with a demand power or torque reference strategy, the demand power or torque reference strategy uses the engine power at a large demand power while the electric power is used at a low demand power, so that the instantaneous efficiency is maximized. Allows selection of power source.

As another example, when the control diversity is implemented by a high voltage battery state of charge (SOC) control strategy, the high voltage battery SOC control strategy is load modeling using all the received information about the path ahead of the driving, and optimizes the entire area or part of the path. The real-time execution of the optimization allows for optimal power distribution (engine start, torque distribution between engine / motor).

Domestic Patent Publication 10-2012-0023409 (March 13, 2012)

However, the PHEV requires the following improvements due to a strategy for implementing control diversity based on power source control.

First, there is a need to improve the fuel efficiency effect by simply improving the power source control based on instantaneous efficiency. Second, considering the operation of the air conditioner in the summer, there is a need not to reduce the fuel efficiency even under the operation of the air conditioner. Third, since the reception of necessary information for road modeling and real-time optimization of the forward route is technically limited, there is a need to overcome it. Fourth, since a high performance microprocessor is required for real-time optimization of the received necessary information, there is a need to solve it.

In view of the above, the present invention applies a full-load classification strategy to the setting of the engine starting reference power, and in particular, the engine starting reference power setting value is increased by an optimization technique using the full-load consumption consumed by the driving motor. The purpose of the present invention is to provide a fuel efficiency improvement method for electric loads of an environmentally friendly vehicle that improves fuel efficiency with high control efficiency for a long and medium distance longer than the all electric range.

The control method of the present invention for achieving the above object is, if the controller recognizes the auto mode using the drive motor as the driving power in the operating state of the engine set to the engine starting reference power, the auxiliary according to the operation of the auxiliary electric load Full-load load consumption power detection is performed, and the supplementary full-load load power correction is performed such that the engine starting reference power is set down according to the detection of the auxiliary full-load consumption power, and the engine is compared with the application of the engine starting reference power in the auto mode. It is characterized in that the utilization becomes higher as the engine starting reference power is lowered.

In a preferred embodiment, the auto mode is operated using an AVN or the like as an input device together with a button switch, a voice command and a (P) HEV dedicated mode.

In a preferred embodiment, the auxiliary electric load consumption power is detected through monitoring of the air conditioner and the LDC constituting the auxiliary electric load, and the auxiliary electric load consumption power correction according to the operation of the air conditioner and the LDC is an auxiliary electric load factor. (factor) is applied, and the auxiliary electric load factor weights the power consumption of the air conditioner compared to the LDC power consumption of the LDC.

In a preferred embodiment, the auxiliary electric load consumption power correction is made to follow the linear drop characteristic of the battery SOC according to the operation of the air conditioner obtained as a result of the optimization using the dynamic programming technique.

In a preferred embodiment, the auxiliary electric load consumption power correction reduces the control sensitivity caused by the instantaneous fluctuation of the power consumption by applying a low pass filter technique or a moving average technique. In the low pass filter technique, a filter gain is provided by processing a low pass filter of a raw value of the auxiliary electric load consumption power. The moving average technique processes a moving average of a detected value of the auxiliary electric load consumption power.

In a preferred embodiment, the linearity of the auxiliary electric load consumption power is used to down the set value, and the linearity of the auxiliary electric load consumption power reflects the magnitude of the auxiliary electric load consumption power, and the driving is performed. It is applied to the section between the CD mode which runs using only a motor, and the CS mode which runs by mixing the said engine with the said drive motor. In particular, the linear engine starting reference power is lower than the engine starting reference power of the CD mode and is higher than the engine starting reference power of the CS mode by applying the engine starting reference power as a starting point when the air conditioning load is not used.

In a preferred embodiment, the controller switches to CD mode control for driving using only the drive motor or CS mode control for mixing with the engine and the driving motor when the auto mode is not recognized, and the CD mode. In each of the control and the CS mode control, the set value of the engine starting reference power is maintained.

In a preferred embodiment, the controller includes an engine starting reference power map to which the engine starting reference power is mapped, and the engine starting reference power map includes a set engine starting reference power reflecting the set value and a calculated engine starting reflecting the set value down. The engine start reference power is distinguished by reference power.

 In a preferred embodiment, the controller is associated with an auto mode input device for recognition of the auto mode, and the auto mode input device includes an AVN and the like together with a button switch, a voice command and a (P) HEV dedicated mode.

In addition, the environmentally friendly vehicle of the present invention for achieving the above object corrects the auxiliary electric load consumption power detected in the auto mode, and uses the linearity of the auxiliary electric load consumption power to start the engine. A controller which lowers the set value of the power to increase the engine usability of the auto mode compared to the engine starting reference power; Characterized in that the included.

In a preferred embodiment, the controller includes an engine start reference table in which the set engine start reference power and the calculated engine start reference power are constructed in a table or a start-up power map diagram to control the set engine start reference power and the calculated engine start reference power. A power map is provided.

In a preferred embodiment, the controller maintains a reference value for the set engine starting reference power in CD (EV) / CS (HEV) mode control.

The environmentally friendly vehicle of the present invention implements the following effects and effects by improving fuel efficiency by classifying the electric load.

First, the control variability of the PHEV's Auto Mode is greatly improved through improved fuel economy at longer and longer distances than the All Electric Range. Second, PHEV's Auto Mode is a control strategy of the dynamic programming method for the optimization result. By lowering the engine starting reference power at the high air conditioning load, the use of engine power is increased, which is advantageous in terms of fuel efficiency. Third, the system efficiency is improved when controlling the auto mode for medium to long distance driving by using the engine power advantageous in terms of fuel economy. Fourth, the control strategy for lowering the engine starting reference power is more precisely established because it monitors the power consumption according to the operation of the air conditioner and LDC (low voltage DC / DC converter) compared to the driving motor with the full-load.

Figure 1 is a flow chart of the electric load-loading division fuel efficiency improvement method applied to an eco-friendly vehicle according to the present invention, Figure 2 is an example of an eco-friendly vehicle in which the electric load-loading division fuel efficiency improvement control according to the present invention is performed, Figure 3 is Figure 4 is an example of the setting diagram of the required power reference value for the engine start, which is the standard using the engine power due to the air conditioner operation (ON / OFF) according to, Figure 4 is the engine starting reference power to which the full-load load classification according to the present invention is applied 5 is an example of a linear drop diagram of an air conditioner and a battery state of charge (SOC) through an optimization technique according to the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Since the exemplary embodiments of the present invention may be implemented in various different forms by one of ordinary skill in the art to which the present invention pertains, Not limited to the embodiment.

In an embodiment of the present invention, the eco-friendly vehicle is described as a plug-in hybrid electric vehicle capable of a forced charging mode in addition to an auto mode, a CD (EV) mode, and a CS (HEV) mode. It also includes a typical hybrid vehicle.

In this case, auto mode, CD (EV) mode, CS (HEV) mode definition and driving mode characteristics are as follows.

Auto mode: EV mode can be entered. High voltage battery A function that considers driving conditions for high fuel efficiency in SOC state, and distributes electric power and engine power properly and uses high voltage battery to the destination when the destination is determined. We can use a strategy to increase fuel economy by fully utilizing the SOC of (e.g., up to EV mode deactivation SOC).

CD mode (Charge Depleting Mode): This mode is driven by electric power only. It can be used only when the SOC of the high voltage battery is over a certain value. When the required power exceeds the maximum power of the electric power, the engine power can be used. Therefore, Auto Mode enables fuel economy gains for mid to long distance driving, which cannot be driven by EV. Therefore, the CD (EV) mode is driven mainly by electric power, so it is possible to obtain noise, riding comfort, and fuel efficiency gains when driving within a distance that can be driven by EV after external charging.

CS mode (Charge Sustaining Mode): A mode that uses a mixture of engine and electric power. It uses the same power distribution strategy as a hybrid vehicle, and does not use the SOC Band as a full range of high voltage batteries. It is used only in SOC, and it enters unconditionally in SOC situation where EV mode cannot be entered. Therefore, CS (HEV) mode enables the most efficient operation in SOC situation where EV mode cannot be entered.

Referring to FIG. 1, the electric load improvement method for fuel efficiency is applied by setting engine starting reference power by performing auto mode control (S10 to S80) with a calculated engine starting reference power that is adapted to an operation state of an auxiliary electric load. It is characterized by differentiating from CD (EV) / CS (HEV) mode control (S10-1, S70-1, S80-1).

In particular, the auto mode through the electric load division fuel efficiency improvement method is a technique of dynamic programming (optimization method when the partial problems share the partial problems again due to the overlap of the partial problems) for the energy consumption of the auxiliary electric load. The CD (EV) / CS (HEV) transition request power reference value is varied as a result of the optimization using the CD (EV) / CS (HEV) transition. Apply to improve fuel economy.

Therefore, the Auto Mode sets the calculated engine starting reference power to lower the reference value compared to the engine starting reference power to increase the engine usage during driving, thereby making the following difference from the existing EV Auto, Adaptive CD / CS, and Auto CD. Can have.

For example, the auto mode does not need to consider driving requirements of EV Auto for CD (EV) / CS (HEV) transition, and loads like the high load CS and the low load CD of the adaptive CD / CS. There is no need for CD / CS mode transition condition, and there is no need to set EV line like “CS <Auto CD <CD” of Auto CD. Furthermore, the auto mode is not limited to a high load engine starting strategy such as EV Auto, and does not require a complementary strategy for low fuel efficiency effects such as Adaptive CD / CS and Auto CD.

Referring to FIG. 2, the eco-friendly vehicle 1 includes an engine ECU (Electronic Control Unit) 3, a MCU (Motor Control Unit) 5, an auxiliary electric load system 7, and an AVN (Audio & Video Navigation System) ( 8), an auto mode input device 9 and a controller 10 associated with the engine start reference power map 10-1 to control the set engine start reference power and the calculated engine start reference power. In addition, the eco-friendly vehicle 1 includes a vehicle-mounted sensor that detects information of an engine, a motor, and other vehicle systems and transmits the information to the engine ECU 3, the MCU 5, and the controller 10.

In one example, the engine ECU 3 controls an engine, and the MCU 5 controls a motor.

For example, the auxiliary electric load system 7 generates an auxiliary electric load that brings energy consumption power other than the motor, and includes a FATC (Full Auto Temperature Control System), a LDC (Low Voltage DC / DC Converter), and a PTC (Positive Temperature). Coefficient) to generate auxiliary electric load during its operation. In this case, the FATC may be a system for maintaining a comfortable indoor space irrespective of an external condition by automatically adjusting a blowing direction and a blowing amount, indoor air and inflow air, or simply an air conditioner of a vehicle. The LDC performs charge and discharge control and 12V voltage conversion control of a 12V battery that forms a battery system together with a 48V battery. The PTC is a heater.

In one example, the AVN 8 and the auto mode input device 9 generate signals for operating in the auto mode. The AVN 8 performs basic functions such as driving path setting and GPS signal-based vehicle location voice information guidance based on a vehicle's origin and destination, and shares navigation information with the controller 10. The auto mode input device 9 performs an auto mode control entry determination in which a medium to long distance driving mode selection, a destination setting, a distance to the destination and an EV driving distance are made, and a selection button for selecting a driver ( That is, it is equipped with a device such as a button switch input) and a microphone for driver's voice recognition (ie voice command input), and recommends a PHEV-only mode suitable for a route when performing an auto mode entry release or setting a route Auto mode selection, etc., can be performed during mode only signal).

For example, the controller 10 processes the detection signal of the on-vehicle sensor as input data, receives a GPS signal, calculates engine starting reference power, and references the calculated engine starting reference power in auto mode control. While the value is lowered than the set engine start reference power, it maintains the reference value with the existing set engine start reference power in the CD (EV) / CS (HEV) mode control. The engine starting reference power map 10-1 constructs the set engine starting reference power and the calculated engine starting reference power as a table or a start-up power map diagram.

Hereinafter, the electric load-loading division fuel efficiency improving method applied to the eco-friendly vehicle of FIG. 1 will be described in detail with reference to FIGS. 2 to 5. In this case, the control subjects are the controller 10 connected to the engine ECU 3 and the MCU 5, and the control targets are the engine controlled by the engine ECU 3 and the motor controlled by the MCU 5.

First, the controller 10 performs a determination on the auto mode selection of S10. 2, the controller 10 applies the AVN 8 and the auto mode input device 9 to the determination of the auto mode selection. Therefore, the controller 10 can determine the auto mode selection as the AVN 8, and can determine the button switch operation of the driver selection of the auto mode input device 9 or the voice command of the driver or the PHEV dedicated mode. If the auto mode is not selected at this stage, the controller 10 maintains or switches the CD (EV) / CS (HEV) mode control (S10-1, S70-1, S80-1) to be described in detail later. On the other hand, when the auto mode is selected in this step, the controller 10 selects the medium- and long-distance driving mode for entering the auto mode control, whether the destination is set, and compares the distance to the destination and the EV driving distance. Is the same as

Subsequently, the controller 10 performs monitoring of the auxiliary electric load operation state of S20. Referring to FIG. 2, the controller 10 applies the operating state of the auxiliary electric load system 7. In this case, the auxiliary electric load is described as air consumption power according to the operation of the air conditioner and the LDC, but is not limited thereto.

Subsequently, the controller 10 determines the air conditioner alone auxiliary electric load of S30 through the auxiliary electric load monitoring. In this case, the air conditioner is first applied to the auxiliary electric load based on FIG. 3.

Referring to FIG. 3, the SOC profile of the battery which is the highest fuel economy does not vary greatly depending on whether the air conditioner is operating, but in the case of the required power reference value for starting the engine, which is a criterion for using engine power, the air conditioner is turned on. This is due to the lower setting of the air conditioner. Therefore, in the case of a high air conditioning load such as an air conditioner, it is proved to be advantageous in terms of fuel economy to lower the required power reference value for starting the engine in order to increase the use of the engine than in the case of high air conditioning load.

Subsequently, the controller 10 detects power consumption of the air conditioner when the air conditioner is operated alone as in S40. On the other hand, the controller 10 detects air conditioner power consumption and LDC power consumption when the S50, the air conditioner, and the LDC operate together, and assigns an auxiliary electric load factor to reflect energy consumption according to the operation of the S51 air conditioner and the LDC. Give it. In this case, the auxiliary electric load factor is applied to increase the ratio of air conditioner power consumption to LDC power consumption.

Further, the controller 10 performs an auxiliary electric load consumption power correction of S60, but applies a low pass filter technique of S60-1 or a moving average technique of S60-2. This is because the power consumption of air conditioners and other electric fields, including LDCs, are momentarily fluctuating to make the control sensitive, and power consumption processing by low pass filter and moving average techniques allows insensitive control even in the instantaneous change. Because.

For example, the calculation of the supplementary electric field load power consumption correction value using the low pass filter technique (S60-1) is described as "secondary electric field load power consumption correction value = low pass filter (secondary electric field load power consumption raw value) x filter gain (filter gain). ) Settings ”. In the calculation of the auxiliary electric load consumption power correction value using the moving average technique (S60-2), "secondary electric load consumption power correction value = moving average (auxiliary electric load consumption power raw value)" is applied.

Here, the auxiliary electric load consumption power is an air conditioner, the raw value of the low pass filter (auxiliary electric load consumption power raw value) is a detection value of the air conditioning consumption power, and the filter gain setting is the linear SOC drop diagram of FIG. It is a reflected value, and the raw value of the moving average (auxiliary electric field power consumption power value) is a detection value of air conditioner / LDC power consumption.

After that, the controller 10 applies the calculated engine starting reference power of S70, and performs the auto mode control of S80 through this.

 Referring to FIG. 4, the engine starting reference power is divided into a set engine starting reference power and a calculated engine starting reference power.

For example, the set engine start reference power is a CD (EV) mode engine start reference power at which the maximum output of the drive motor is output, air conditioning is not used (that is, the auxiliary electric load is not operated). HEV) mode engine start reference power, and the air conditioning unused engine start reference power is set between the highest CD (EV) mode engine start reference power and the lowest CS (HEV) mode engine start reference power. This setting is the same as the existing case.

On the other hand, the calculated engine starting reference power is calculated as the auxiliary electric load power consumption between the interval between the unoperated engine starting reference power and the CS (HEV) mode engine starting reference power, but is linear with respect to the magnitude of the auxiliary electric load consumption power. Is set to a lowered relationship. In other words, the change of the calculated engine starting reference power is set to have linearity with respect to the auxiliary electric load consumption power, and the linearity is higher when the calculated engine starting reference power is operated when the air conditioner and the LDC are operated. Lower it. In particular, the start of the linearity is lower than the engine starting reference power of the CD mode (Charge Depleting Mode), and maintained higher than the engine starting reference power of the CS mode (Charge Sustaining Mode).

As a result, as the auxiliary electric load consumption power increases, the engine starting demand power reference value can be lowered, which can increase the fuel consumption, which is good for fuel consumption.

Referring also to Figure 5, it illustrates that the operation of the air conditioner is derived from a linear SOC down curve from the optimization result using the dynamic programming technique. In this case, the dynamic programming technique is a result of performing an analysis depending on whether the air conditioner (ie, air conditioning load) is operated in the same driving cycle, and this is because the falling rate of the SOC profile is linear without being dependent on the air conditioning operation. The low reference value of the required power for starting the engine in air conditioning demonstrates the advantage of frequent fuel economy. Therefore, the above result reflects the air-conditioning load usage (ie, auxiliary electric load) to the engine starting reference power of the existing Auto Mode, and it is possible to establish a control strategy to lower the engine starting reference power when the load is large. The strategy proves that the system efficiency of the eco-friendly vehicle 1 can be improved when controlling the auto mode for long-distance driving.

Referring back to FIG. 1, when the auto mode is not selected in S10, the controller 10 applies the set engine starting reference power of S70-1, and performs CD mode control or CS mode control of S80-1 through this. give. In this case, referring to FIG. 4, since the CD mode control brings the highest engine starting reference power, the maximum driving motor output is used for driving, while the CS mode control brings the lowest engine starting reference power. Make the most of your engine usage while using the minimum drive motor output.

Therefore, since the CD mode control is driven mainly by electric power as in the conventional definition and operation characteristics, the fuel efficiency gain is achieved when driving within a distance (near distance) that can be driven by EV after noise, riding comfort, and external charging. In addition, the CS mode control is the most efficient operation in the SOC situation impossible to enter the EV mode, as in the conventional definition and operation characteristics.

As described above, the full-load load classification fuel efficiency improvement method of the environmentally friendly vehicle according to the present embodiment corrects the auxiliary electric load consumption power detected in the auto mode, and linearity of the auxiliary electric load consumption power. Auto mode is controlled while the set value of the engine starting reference power is lowered by using the engine, which greatly improves the engine utilization compared to the auto mode in which the set value is maintained.

1: Eco-friendly vehicle 3: Engine ECU (Electronic Control Unit)
5: MCU (Motor Control Unit)
7: auxiliary electric load system 8: AVN (Audio & Video Navigation System)
9: Auto mode input device 10: Controller
10-1: engine start reference power map

Claims (25)

When the controller 10 recognizes an auto mode using the driving motor as driving power in the engine operating state set to the engine starting reference power, the auxiliary electric load consumption power is detected according to the operation of the auxiliary electric load. The auxiliary electric load consumption power correction is performed such that the engine starting reference power is set down according to the detection of the auxiliary electric load consumption power, and the engine usability is compared to the application of the engine starting reference power in the auto mode. Higher as the engine start reference power is lowered
Control method characterized in that.
The control method according to claim 1, wherein the auto mode is operated by a signal.
The control method of claim 2, wherein the signal is any one of a button switch, an audio and video navigation system (AVN), and a voice command.
The control method according to claim 1, wherein the auxiliary electric load consumption power is detected through monitoring of the auxiliary electric load.
The control method according to claim 4, wherein the auxiliary electric load includes an air conditioner and a low voltage DC / DC converter (LDC).
The method according to claim 5, wherein the auxiliary electric load consumption power correction according to the operation of the air conditioner and the LDC is applied to the auxiliary electric load factor (factor), the auxiliary electric load factor (factor) compared to the LDC power consumption of the LDC The control method characterized in that to give a weight to the power consumption of the air conditioner.
The control method according to claim 1, wherein the correction of the auxiliary electric load consumption power is adapted to a linear falling characteristic of the battery SOC, and the linear falling characteristic reflects the operation of the air conditioner.
The control method according to claim 7, wherein the linear falling characteristic is derived by optimization of a dynamic programming technique.
The control method according to claim 1, wherein the auxiliary electric load consumption power correction reduces the sensitivity of the control caused by the instantaneous variation of the power consumption by applying a low pass filter technique or a moving average technique.
The control method according to claim 9, wherein the low pass filter technique provides a filter gain by performing a low pass filter process on a raw value of the auxiliary electric load consumption power.
The control method according to claim 9, wherein the moving average technique processes a moving average of a detected value of the auxiliary electric load consumption power.
The control method according to claim 1, wherein the set value is used for linearity with respect to the auxiliary electric load consumption power.
The control method according to claim 12, wherein the linearity reflects the magnitude of the auxiliary electric load consumption power.
The method of claim 13, wherein the linearity is in the interval between the CD mode (Charge Depleting Mode) to run using only the drive motor, the CS mode (Charge Sustaining Mode) to run the engine mixed with the drive motor Control method characterized in that applied.
15. The method of claim 14, wherein the engine starting reference power of the linearity (linearity) is lower than the engine starting reference power of the CD mode (Charge Depleting Mode), it is maintained that higher than the engine starting reference power of the CS mode (Charge Sustaining Mode) Control method characterized in that.
The control method as claimed in claim 14, wherein the linearity applies an engine starting reference power as a starting point when no air conditioning load is used.
The CD mode control of claim 1, wherein the controller switches to CD mode control that runs using only the drive motor or CS mode control that runs by mixing with the engine and the drive motor when the auto mode is not recognized. And a set value of the engine starting reference power in each of the control and the CS mode control.
The control method according to claim 1, wherein the controller comprises an engine starting reference power map to which the engine starting reference power is mapped.
The control method according to claim 18, wherein the engine starting reference power map divides the engine starting reference power into a set engine starting reference power and a calculated engine starting reference power.
The control method according to claim 19, wherein the set engine starting reference power reflects the set value, and the calculated engine starting reference power reflects the set value down.
The method of claim 1, wherein the controller is connected to an input device for recognizing the auto mode, and the input device includes a button switch, a voice command, and an AVN.
The auxiliary electric load consumption power detected in the auto mode is corrected, and the set value of the engine starting reference power is lowered by using the linearity of the auxiliary electric load consumption power. A controller that increases engine usability compared to the engine starting reference power;
Eco-friendly vehicle comprising a.
23. The environment-friendly vehicle of claim 22, wherein the controller is provided with an engine starting reference power map for controlling the set engine starting reference power and the calculated engine starting reference power.
24. The eco-friendly vehicle according to claim 23, wherein the engine starting reference power map is constructed with a table or a start-up power map diagram of the set engine starting reference power and the calculated engine starting reference power.
The environmentally friendly vehicle of claim 22, wherein the controller maintains a reference value for the set engine starting reference power in the CD (EV) / CS (HEV) mode control.

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