JP2007331688A - Electric power generation control apparatus of hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform high level charge control while enabling motor travelling, motor assist travelling, and energy regeneration freely at anytime. <P>SOLUTION: A hybrid vehicle 1 comprises an electric power generator 17 to be driven by an engine 11, a battery 20 for charging electric energy to be generated by the electric power generator 17, and a motor 12 to be driven by the electric energy generated by the electric power generator 17 or the electric energy to be charged in the battery 20. A control unit 30 estimates amount of charge in the battery 20, and controls the electric power generator 17 so that the estimated amount of charge becomes the targeted amount of charge. The electric power generator 17 is controlled so that the amount of charge of the battery 20 becomes higher than the targeted amount of charge when an execution condition of the high level charge control is satisfied. However, the execution of the high level charge control is suspended until the vehicle 1 stops when the execution condition of the high level charge control is satisfied during cruise of the vehicle 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power generation control device for a hybrid vehicle, and more particularly to a power generation control device for a hybrid vehicle configured to control a charge amount of a battery to a predetermined target charge amount.

  Conventionally, regardless of whether it is a series type or a parallel type, the generator includes an engine and an electric motor, and is driven by the engine to generate electric energy, and a battery that stores electric energy generated by the generator, There is known a hybrid vehicle configured to drive the motor by electric energy generated by the generator or electric energy stored in the battery. In that case, the battery of the hybrid vehicle is composed of an assembled battery of several cells to several hundred cells, and there is no problem when the charge amount is in the normal range of, for example, 50 to 60%, but the charge amount is larger than the normal range. If the battery is in an overdischarge region or an overdischarge region that is less than the normal region, there is a problem in that the deterioration of the battery is promoted. Therefore, by detecting the charging current and discharging current of the battery and adding the integrated value of these charging current and discharging current to the previous charging amount, the latest battery charging amount is estimated, and the estimated charging amount is The generator is controlled so that it stays in the normal range.

  However, due to the fact that the detected values of the charging current and discharging current contain errors, and the battery self-discharges when the vehicle is not running, the estimated value of the charging amount with time elapses. The accuracy of the estimated value of the battery charge will decrease, and as a result, even if the charge amount is intended to remain within the normal range, the charge amount will actually fall into the overcharge range or overdischarge range. A problem such as migration has occurred.

Therefore, for example, in Patent Document 1, the battery charge amount detected in the load connection state is calibrated based on the battery charge amount accurately detected in the load release state, so that the charge amount can be accurately determined even in the load connection state. The technology to detect is described. Patent Document 2 describes a technique for accurately detecting the amount of charge by detecting that the battery has been charged to a predetermined capacity in a state where the battery is activated after the start of the engine is completed. .
JP 2002-51470 (paragraph 0006) JP2004-168126 (paragraphs 0011 and 0012)

  By the way, in general, as a characteristic of the battery, there is a characteristic that the battery voltage increases as the charge amount increases, and the battery voltage decreases as the charge amount decreases, so by detecting the battery voltage using this characteristic, It is proposed to accurately and easily detect the amount of battery charge. However, when the charge amount fluctuates in the middle charge range including the normal range, the battery voltage does not change much, and fluctuates in the high charge range where the charge amount is greater than the middle charge range or in the low charge range where the charge amount is less than the middle charge range. Since the battery voltage greatly fluctuates when the battery is charged, it is necessary to perform high charge control for once increasing the battery charge amount to the high charge range in order to accurately detect and determine the charge amount from the battery voltage. Then, if this high charge control is performed while the vehicle is running, the use of the battery is restricted during that time, so it is impossible to achieve discharge from the battery to the motor, that is, motor driving at start and motor assist at acceleration, In addition, charging from the motor to the battery, that is, energy regeneration at the time of deceleration cannot be achieved, resulting in a disadvantageous effect in terms of fuel consumption and running performance.

  The present invention addresses the problem in the hybrid vehicle configured to control the battery charge amount to a predetermined target charge amount and perform high charge control to make the battery charge amount higher than the target charge amount. It is an object of the present invention to perform high charge control while allowing motor travel, motor assist, energy regeneration, etc. to be freely achieved at any time.

  In order to solve the above-mentioned problem, the invention according to claim 1 is directed to an engine, a generator that is driven by the engine to generate electric energy, a battery that stores electric energy generated by the generator, A power generation control device for a hybrid vehicle comprising: electric energy generated by a generator or a motor driven by electric energy stored in the battery; and a charge amount estimating means for estimating a charge amount of the battery; The generator is controlled so that the charge amount estimated by the charge amount estimation means becomes a predetermined target charge amount, and when a predetermined high charge control execution condition is satisfied, the charge amount of the battery is set to the target charge amount. When the generator control means for controlling the generator so as to be higher than the charge amount, and the execution condition of the high charge control is established while the vehicle is running, Both are characterized by having a control-hold means for holding the execution of the high charging control until stops.

  Next, the invention according to claim 2 of the present application is the power generation control device for the hybrid vehicle according to claim 1, wherein the engine is automatically stopped when a predetermined execution condition is satisfied when the vehicle is stopped. Stop means is provided, and when the vehicle stops, the control suspension means performs high charge control in preference to automatic engine stop by the idle stop means.

  Next, the invention according to claim 3 of the present application is the power generation control device for a hybrid vehicle according to claim 1, wherein the control suspension unit is configured to stop the vehicle and perform an engine stop operation. The high charge control is executed.

  Next, the invention according to claim 4 of the present application is the power generation control device for a hybrid vehicle according to claim 2 or 3, further comprising notification means for notifying that during execution of the high charge control. It is characterized by being.

  Next, the invention according to claim 5 of the present application is the power generation control device for a hybrid vehicle according to claim 1, wherein the high charge control is control for determining a charge amount of the battery. And

  The invention according to claim 6 of the present application is the power generation control device for a hybrid vehicle according to claim 5, wherein the execution condition of the high charge control is every time a certain period elapses. And

  First, according to the first aspect of the present invention, in a hybrid vehicle including an engine, a generator, a battery, and a motor, when the execution condition of the high charge control is satisfied while the vehicle is running, until the vehicle stops. Since the execution of the high charge control is suspended, the high charge control is not performed while the vehicle is running, but is performed when the vehicle is stopped. As a result, the use of the battery is no longer restricted with the execution of the high charge control while the vehicle is running, and motor running at the start, motor assist at the time of acceleration, or energy regeneration at the time of deceleration can be freely achieved at any time. This will not adversely affect fuel economy and driving performance.

  Next, according to the second aspect of the invention, when the vehicle stops, the high charge control is executed in preference to the idle stop. By using this, it is possible to satisfactorily execute the high charge control without affecting other equipment or control.

  Next, according to the invention described in claim 3, since the high charge control is executed when the vehicle stops and the engine stop operation is performed, the engine may be originally stopped in this case as well. By using the period, it is possible to satisfactorily execute the high charge control without affecting any other equipment or control.

  Next, according to the fourth aspect of the present invention, as described above, when the high charge control is executed in preference to the idle stop, or when the high charge control is executed when the engine stop operation is performed. In this case, since this is notified, the passenger's uncomfortable feeling about the continued operation of the engine in a situation where the engine is originally stopped is reduced.

  Next, according to the fifth aspect of the present invention, since the high charge control is control for determining the battery charge amount, a decrease in accuracy of the estimated value of the battery charge amount is suppressed.

  According to the sixth aspect of the present invention, since the high charge control is executed every time a certain period of time elapses, the battery charge amount is determined before the battery charge amount estimation accuracy is greatly reduced. The quantity estimate will be modified. Hereinafter, the present invention will be described in more detail through the best mode for carrying out the invention.

  FIG. 1 is a system configuration diagram of a hybrid vehicle 1 according to the present embodiment. The hybrid vehicle 1 is of a parallel type, and includes an engine 11, a generator 17 that is driven by the engine 11 to generate electric energy, a hybrid battery 20 that stores electric energy generated by the generator 17, And an electric motor 12 driven by the electric energy generated by the generator 17 or the electric energy stored in the hybrid battery 20.

  In that case, a power split mechanism 13 is provided between the engine 11 and the generator 17, and a power merging mechanism 14 is provided between the electric motor 12 and the speed reducer 15. The power split mechanism 13 and the power merge mechanism 14, and the electric motor 12 and the speed reducer 15 are connected by a mechanical power transmission path. On the other hand, a three-phase alternating current flows between the generator 17 and the inverter 18 and between the electric motor 12 and the inverter 19, and a direct current flows between the inverters 18 and 19 and the hybrid battery 20.

  When the vehicle 1 travels with the power of the engine 11, the power of the engine 11 is transmitted to the left and right drive wheels 16 and 16 via the power split mechanism 13, the power merge mechanism 14, and the speed reducer 15. Further, when the vehicle 1 travels with the power of the motor 12 using the electric energy generated by the generator 17, the power of the engine 11 is transmitted to the generator 17 via the power split mechanism 13, and the generator 17 generates power. The electrical energy thus supplied is supplied to the motor 12 via the inverters 18 and 19, and the power of the motor 12 is transmitted to the left and right drive wheels 16 and 16 via the power merging mechanism 14 and the speed reducer 15. Further, when the vehicle 1 travels with the power of the motor 12 using the electric energy stored in the battery 20, the electric energy stored in the battery 20 is supplied to the motor 12 via the inverter 19, and the motor 12. Is transmitted to the left and right drive wheels 16 and 16 via the power merging mechanism 14 and the speed reducer 15. When charging the battery 20 with the power of the engine 11, the power of the engine 11 is transmitted to the generator 17 via the power split mechanism 13, and the electric energy generated by the generator 17 passes through the inverter 18. And supplied to the battery 20. When the battery 20 is charged with the regenerative energy of the vehicle 1, the regenerative energy from the drive wheels 16 and 16 is transmitted to the motor 12 via the speed reducer 15 and the power merging mechanism 14, and the motor 12 generates power ( The electric energy that is also used by the motor 12 as a generator is supplied to the battery 20 via the inverter 19.

  The control unit 30 of the vehicle 1 includes a signal from the battery control unit 21 that can detect the charging current and discharging current of the battery 20 and the voltage of the battery 20, a signal from the vehicle speed sensor 31, and a signal from the accelerator pedal 32. A signal, a signal from the brake pedal 33, and a signal from the operation unit 34 for performing a start operation and a stop operation of the engine 11 are input, and based on these signals, the engine 11, the electric motor 12, and the generator 17 are input. And a control signal is output to the meter unit 35 provided in front of the driver's seat. In particular, the control unit 30 estimates the latest charge amount of the battery 20 by adding the integrated value of the charge current and the discharge current to the previous charge amount.

  FIG. 2 is an explanatory diagram of the charge amount of the hybrid battery 20. The battery 20 is composed of an assembled battery of several cells to several hundred cells, and can be charged and discharged freely when the charge amount (SOC: State of charge) is in a normal range of 50 to 60%. The generator 17 is controlled so that the amount of charge estimated by the unit 30 stays within this normal range (more specifically, converges to a predetermined target charge amount within the normal range). The discharge request area of 60 to 70% where the amount of charge is larger than the normal area is an area where the battery 20 is positively discharged if there is an opportunity to discharge. The forcible discharge area of 70% or more where the charge amount is greater than the discharge request area is an area where the battery 20 is forcibly discharged under any circumstances. Otherwise, the deterioration of the battery 20 will be promoted. On the other hand, the charge request area of 40 to 50% where the charge amount is smaller than the normal use area is an area where the battery 20 is positively charged if there is an opportunity to charge. The forcible charging range where the amount of charge is 40% or less, which is less than the charging request range, is a region where the battery 20 is forcibly charged in any situation. Otherwise, the deterioration of the battery 20 will be promoted.

  FIG. 3 is an explanatory diagram of the high charge control of the hybrid battery 20. The battery 20 has a characteristic that the battery voltage (V) increases as the charge amount (SOC) increases, and the battery voltage (V) decreases as the charge amount (SOC) decreases. However, when the charge amount fluctuates in the middle charge range (20 to 80% in the example) including the normal range (50 to 60%), the battery voltage does not change much. In other words, the detection accuracy of the battery charge based on the battery voltage is low. On the other hand, when the charge amount fluctuates in a high charge range (80% or more in the example) greater than the middle charge range or a low charge range (20% or less in the example) less than the middle charge range, the battery voltage greatly fluctuates. To do. In other words, the battery charge amount detection accuracy based on the battery voltage is high. Therefore, in order to accurately detect and determine the battery charge amount based on the battery voltage using this characteristic, high charge control for temporarily raising the battery charge amount to a high charge range (80% or more) is performed. [Corresponding to the configuration of claim 5].

  For example, it is assumed that the charge amount is currently in a black circle. From here, the power generation amount of the generator 17 is increased, and the charge amount of the battery 20 is increased as shown by the arrow (i). Then, when the battery voltage rises to the predetermined determination voltage Vo, the charging of the battery 20 is terminated, and the charge amount of the battery 20 is fixed to A. Thereafter, the generator 17 is controlled so that the charge amount of the battery 20 converges to a predetermined target charge amount in the normal range, so that the charge amount of the battery 20 settles in the normal range as indicated by an arrow (ii) ( White circle).

  FIG. 4 is a time chart of conventional control of the vehicle 1. In the figure, when the engine is “OFF”, the fuel supply is stopped and no torque (power) is output, and when the engine is “ON”, the fuel is supplied and torque (power) is output. Say. The vehicle 1 starts at time t1, the vehicle speed increases, and the vehicle 1 is accelerated at time t2. Then, the vehicle 1 decelerates at time t3, and the vehicle 1 stops at time t4, for example, by waiting for a signal. During this time, when the vehicle starts, the motor 12 travels and the battery 20 is discharged. When the vehicle speed increases, the engine 11 is switched to running and the battery 20 stops discharging. During acceleration, the motor 12 assists and the battery 20 is discharged. And at the time of deceleration, energy is regenerated and the battery 20 is charged.

  Subsequently, the vehicle 1 restarts at time t5, the vehicle speed is increased, the vehicle 1 is decelerated at time t6, and the vehicle 1 is parked in the garage at time t7. During this time, when the vehicle restarts, the motor 12 travels and the battery 20 is discharged. When the vehicle speed increases, the engine 11 is switched to running and the battery 20 stops discharging. And at the time of deceleration, energy is regenerated and the battery 20 is charged. In this case, between time t4 and t5, predetermined execution conditions when the vehicle 1 stops (for example, the vehicle speed is almost zero, the accelerator pedal 32 is not depressed, the brake pedal 33 is depressed, etc.) When is established, idle stop control for automatically stopping the engine 11 is executed. Further, the engine 11 is stopped at time t8 after time t7 (using the engine start / stop operation unit 34 in FIG. 1).

  In such conventional control, since the high charge control of FIG. 3 is performed even while the vehicle 1 is traveling (periods T1 and T2), the use of the battery 20 is restricted while the high charge control is being executed. . Therefore, discharging from the battery 20 to the motor 12, that is, assisting by the motor 12 at the time of starting and acceleration by the motor 12 cannot be achieved, and charging from the motor 12 to the battery 20, that is, energy regeneration at the time of deceleration is not achieved. Since it cannot be achieved, there is a disadvantage in terms of fuel consumption and driving performance.

  Therefore, as illustrated in FIG. 5, in the present embodiment, when the execution condition of the high charge control is satisfied while the vehicle 1 is traveling, the execution of the high charge control is performed until the vehicle stops (including parking). Is suspended [corresponding to the configuration of claim 1]. As a result, for example, when the high charge control execution condition is satisfied during the travel period T1 (time t1 to t4) in FIG. 4, the high charge control is executed while the vehicle 1 is stopped (time t4 to tx: period a). Is done. As a result, in period A, the engine 11 is turned “ON” and the battery 20 is charged. For example, when the execution condition of the high charge control is satisfied during the travel period T2 (time t5 to t7) in FIG. 4, the high charge control is executed while the vehicle 1 is parked (time t8 to ty: period a). The As a result, even during the period A, the engine 11 is turned “ON” and the battery 20 is charged.

  FIG. 6 is a flowchart showing an example of the control of the present invention including the time of stopping (time t4 to t5). In step S1, various signals are read, and in step S2, it is determined whether or not an execution condition for high charge control of the battery 20 is satisfied. Here, the execution condition of the high charge control is, for example, that a certain period has elapsed since the previous high charge control was executed [corresponding to the configuration of claim 6]. That is, the high charge control is executed every time a certain period elapses. The fixed period in this case is determined by the degree of error included in the detected values of the charging current and the discharging current, the self-discharge rate of the battery 20 while the vehicle 1 is not running, etc., for example, several days. .

  If YES in step S2, it is determined in step S3 whether the vehicle is traveling. If the result is YES, in step S4, the execution of the high charge control of the battery 20 is suspended, and then the process returns. On the other hand, if NO in step S2, the process returns as it is, and if NO in step S3, that is, when the vehicle 1 is stopped, the execution condition of the idle stop control is satisfied in step S5. It is determined whether or not. Here, the execution condition of the idle stop control is, for example, that the vehicle speed is substantially zero, the accelerator pedal 32 is not depressed, and the brake pedal 33 is depressed, as described above.

  When YES is determined in step S5, execution of idle stop control is suspended in step S6, and then high charge control is started in step S7. On the other hand, if NO at step S5, the process directly proceeds to step S7. Next, in step S8, a text for calling attention such as “during battery maintenance” is displayed on the meter unit 35 of FIG. 1 [corresponding to the configuration of claim 4]. Of course, voice notification may be performed instead of or together with the display of text and graphics. Next, in step S9, the engine 11 is maintained “ON”, and in step S10, the battery 20 is charged.

  As a result, when it is determined in step S11 that the battery voltage has reached the determination voltage Vo as shown in FIG. 3, the battery charge amount (SOC) is fixed to A in step S12. On the other hand, when it is determined in step S11 that the battery voltage has not yet reached the determination voltage Vo, steps S8 to S10 are repeated. In step S13, the high charge control is terminated. Instead, in step S14, idle stop control is started. And it becomes the end.

  FIG. 7 is a flowchart showing an example of the control of the present invention including the time of parking (from time t7). In step S21, various signals are read, and in step S22, it is determined whether or not an execution condition for high charge control of the battery 20 is satisfied. When YES is determined in the step S22, it is determined whether or not the vehicle is traveling in a step S23. If the result is YES, in step S24, execution of the high charge control of the battery 20 is suspended, and then the process returns. On the other hand, if NO in step S22, the process returns as it is, and if NO in step S23, that is, if the vehicle 1 is parked, it is determined in step S25 whether or not the engine 11 is stopped. . Here, the presence / absence of the stop operation of the engine 11 can be determined based on the signal from the engine start / stop operation unit 34 of FIG. 1 as described above.

  If YES in step S25, the suspension of the engine 11 is suspended in step S26, and then high charge control is started in step S27. On the other hand, if NO in step S25, the system waits until there is a stop operation of the engine 11. Next, in step S28, a text for calling attention such as “during battery maintenance” is displayed on the meter unit 35 of FIG. 1 [corresponding to the configuration of claim 4]. Next, in step S29, the engine 11 is maintained “ON”, and in step S30, the battery 20 is charged.

  As a result, when it is determined in step S31 that the battery voltage has reached the determination voltage Vo as shown in FIG. 3, the battery charge amount (SOC) is fixed to A in step S32. On the other hand, when it is determined in step S31 that the battery voltage has not yet reached the determination voltage Vo, steps S28 to S30 are repeated. In step S33, the high charge control is terminated, and in step S34, the engine 11 is stopped. And it becomes the end.

  As described above, according to the present invention, in the hybrid vehicle 1 including the engine 11, the generator 17, the battery 20, and the motor 12, when the execution condition of the high charge control is satisfied while the vehicle 1 is traveling (step S3). Since the execution of the high charge control is suspended until the vehicle 1 stops (steps S4 and S24), the high charge control is not performed while the vehicle 1 is running and the vehicle 1 is stopped. Will be done sometimes. As a result, the use of the battery 30 is not restricted with the execution of the high charge control while the vehicle 1 is traveling, and the motor 12 travels at the start, the motor 12 assists at the time of acceleration, or the energy regeneration at the time of deceleration is free at any time. To avoid adverse effects in terms of fuel consumption and driving performance.

  Further, when the vehicle 1 stops, the high charge control is executed in preference to the idle stop (steps S6 and S7) [corresponding to the configuration of claim 2]. It is possible to satisfactorily execute the high charge control without any influence on other facilities and control using the good period (during the stop period: times t4 to t5).

  Since the high charge control is executed when the vehicle 1 stops and the engine stop operation is performed (YES in step S25, S27) [corresponding to the configuration of claim 3], in this case as well, the original engine It is possible to satisfactorily execute the high charge control without any influence on other facilities and control by using the period during which 11 may be stopped (during the parking period: time t7).

  Further, as described above, when high charge control is executed in preference to idle stop (steps S6 and S7), or when high charge control is executed when an engine stop operation is performed (YES in step S25, In S27), this is notified (steps S8, S28), so that the occupant's uncomfortable feeling about the continued operation of the engine 11 in a situation where the engine 11 is originally stopped is reduced.

  Further, in the present embodiment, since the high charge control of the battery 20 is control for determining the battery charge amount (steps S12 and S32), a decrease in accuracy of the estimated value of the battery charge amount is suppressed.

  Since the high charge control of the battery 20 is executed every time a certain period of time elapses (steps S2 and S22), the battery charge amount is determined and the battery charge amount is determined before the estimation accuracy of the battery charge amount greatly decreases. Will be corrected.

  The above embodiment is the best embodiment of the present invention, but it goes without saying that various modifications and changes may be made without departing from the scope of the claims. For example, in the above-described embodiment, the vehicle 1 is a parallel hybrid vehicle, but is not limited thereto, and may be a series hybrid vehicle, for example. Moreover, in the said embodiment, although high charge control was control for determining the charge amount of the battery 20, it is not restricted to this, The charge amount of the battery 20 is made higher than a regular use area | region or a medium charge area. It may be control for any purpose.

  As described above in detail with reference to specific examples, the present invention is configured to perform high charge control that controls the battery charge amount to a predetermined target charge amount and makes the battery charge amount higher than the target charge amount. In such a hybrid vehicle, since it is possible to perform high charge control while allowing motor driving, motor assist, energy regeneration, etc. to be freely achieved at any time, it is widely used in the technical field of power generation control devices for hybrid vehicles. Has industrial applicability.

1 is a system configuration diagram of a hybrid vehicle according to a best embodiment of the present invention. It is explanatory drawing of the charge amount of a battery. It is explanatory drawing of high charge control. It is a time chart of conventional control. It is a time chart of control of the present invention. It is a flowchart which shows one example of the control of this invention including the time of a stop. It is a flowchart which shows an example of the control of this invention including the time of parking.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hybrid vehicle 11 Engine 12 Electric motor 17 Generator (generator)
20 Hybrid battery 21 Battery control unit 30 Control unit (charge amount estimation means, generator control means, control hold means, idle stop means)
34 Engine start / stop operation section 35 Meter unit (notification means)

Claims (6)

An engine, a generator that is driven by the engine to generate electric energy, a battery that stores electric energy generated by the generator, electric energy generated by the generator, or electric power stored in the battery A power generation control device for a hybrid vehicle including a motor driven by energy,
Charge amount estimating means for estimating a charge amount of the battery;
The generator is controlled so that the charge amount estimated by the charge amount estimation means becomes a predetermined target charge amount, and when a predetermined high charge control execution condition is satisfied, the charge amount of the battery is set to the target charge amount. Generator control means for controlling the generator to be higher than the charge amount;
And a control holding means for holding the execution of the high charge control until the vehicle stops when the execution condition of the high charge control is satisfied while the vehicle is running. A power generation control device for a hybrid vehicle according to claim 1,
Idle stop means for automatically stopping the engine when a predetermined execution condition is satisfied when the vehicle is stopped is provided,
When the vehicle stops, the control suspension means gives priority to the automatic stop of the engine by the idle stop means and executes the high charge control. A power generation control device for a hybrid vehicle according to claim 1,
The control suspension means is a power generation control device for a hybrid vehicle, which performs high charge control when the vehicle stops and an engine stop operation is performed. A power generation control device for a hybrid vehicle according to claim 2 or 3,
A power generation control device for a hybrid vehicle, comprising a notification means for notifying that during execution of the high charge control. A power generation control device for a hybrid vehicle according to claim 1,
The power generation control device for a hybrid vehicle, wherein the high charge control is control for determining a charge amount of a battery. A power generation control device for a hybrid vehicle according to claim 5,
The power generation control device for a hybrid vehicle is characterized in that the execution condition of the high charge control is every time a predetermined period elapses.

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