JP2012030709A - Coasting control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coasting control device superior in the responsiveness of acceleration when a gas pedal is operated.SOLUTION: The coasting control device includes: a rotation matching control part 4 which touches the clutch after the engine speed is raised to the touch allowable limits determined by the clutch rotation speed at the end of the coasting control; and a coasting control time rotation speed setting part 5 which sets the target engine speed VE at coasting control time between the clutch rotation speed VC, and the idle rotation speed VI.

Description

  The present invention relates to a coasting control device that disengages a clutch during traveling to return the engine to an idle state and suppresses fuel consumption, and relates to a coasting control device that has excellent acceleration responsiveness when an accelerator pedal is operated.

  In the vehicle, when the accelerator pedal is depressed when the clutch is disengaged, the accelerator is opened and the engine is so-called empty, and the engine speed settles at the engine speed corresponding to the accelerator opening. At this time, the driving force generated by the engine and the engine internal resistance (friction) are balanced, and the engine output torque is zero. That is, the engine does not work at all with respect to the outside, and fuel is wasted. For example, if the engine speed is 2000 rpm, the driver can hear a loud engine sound, so that a considerable amount of fuel is consumed wastefully.

  The state in which the engine does not work to the outside is not limited to the idling when the clutch is disengaged, but also occurs while the vehicle is running. That is, the engine only rotates at an engine speed corresponding to the accelerator opening, as in the case of flying, and does not contribute to acceleration / deceleration of the vehicle. At this time, fuel is consumed only for rotating the engine, which is very wasteful.

  The present applicant performs coasting control (also referred to as fuel consumption traveling control) that disengages the clutch and returns the engine to an idle state to reduce fuel consumption when the engine is rotating but not working to the outside. A coasting control device was proposed (Patent Document 1).

JP 2006-342832 A JP-A-8-67175 JP 2001-304305 A

  Conventionally, the target engine speed during coasting control is set to idle speed. That is, as shown in FIG. 12, if the clutch disengagement control by coasting control is being performed, the target engine speed VE is set to the idle speed VI. Thus, the engine speed becomes the idle speed during the coasting control regardless of the engine speed (engine speed corresponding to the vehicle speed) immediately before the coasting control.

  According to this coasting control device, during traveling by coasting control, the clutch is disengaged and the engine speed is the idle speed. At this time, if the driver depresses the accelerator pedal at a predetermined or higher accelerator pedal operation speed, the coasting control is terminated, the clutch is engaged, and the vehicle must be accelerated according to the driver's intention to accelerate. When the clutch is engaged, if there is a large difference between the engine speed and the clutch speed, the driver feels an impact. Therefore, when the engine speed is increased before the clutch is engaged and matched with the clutch speed, or when the engine speed is increased to within an allowable range where the clutch can be engaged without causing an impact. It is desirable to engage the clutch.

  For this reason, it is inevitable that a certain amount of time is required until the engine speed increases from the idle speed to the clutch speed and the clutch is engaged. However, while controlling the rotation alignment and clutch engagement, the driver feels that the vehicle does not start accelerating despite the accelerator operation. When the vehicle speed during coasting control is low, the clutch rotational speed is low, so the time required for rotation adjustment is short and there is no major problem, but when the vehicle speed during coasting control is high, the clutch rotational speed is high, so the engine speed The time required for the rotation adjustment to increase the number from the idle rotation speed to the clutch rotation speed is increased, and a feeling of idling is strongly felt, resulting in dissatisfaction and discomfort.

  Accordingly, an object of the present invention is to provide a coasting control device that solves the above-described problems and has excellent acceleration responsiveness when an accelerator pedal is operated.

  In order to achieve the above object, the present invention starts coasting control by disengaging the clutch and lowering the engine speed to the target engine speed when the engine is being operated without working to the outside. The coasting control execution unit that performs the coasting control, the rotation matching control unit that engages the clutch after increasing the engine speed to within the allowable contact range determined by the clutch rotational speed at the end of the coasting control, and the target engine speed during coasting control A coasting control rotation speed setting unit that is set between the rotation speed and the idle rotation speed is provided.

  The coasting control rotational speed setting unit obtains a difference between the clutch rotational speed and the idle rotational speed, uses a product of the difference and a predetermined value as an offset value, and uses the sum of the offset value and the idle rotational speed as the target engine rotational speed. It may be a number.

  The coasting control determination map is referred to by the clutch rotational speed and the accelerator opening, and the coasting control execution unit includes a plot point of the clutch rotational speed and the accelerator opening on the coasting control determination map within the coasting controllable region. When the accelerator pedal operation speed is within a predetermined range and the plot point of the clutch rotation speed and the accelerator opening passes the coasting control threshold line in the direction of decreasing the accelerator opening, the coasting control is started. The coasting control may be terminated when the operation speed is out of the predetermined range or when the plot point is outside the coasting controllable region.

  The present invention exhibits the following excellent effects.

  (1) The acceleration response when the accelerator pedal is operated is excellent.

It is a block block diagram of the coasting control apparatus of this invention. 1 is a block configuration diagram of a vehicle clutch system to which a coasting control device of the present invention is applied. It is a block diagram of the actuator which implement | achieves the clutch system of FIG. 1 is an input / output configuration diagram of a vehicle to which a coasting control device of the present invention is applied. It is an operation | movement conceptual diagram for demonstrating the outline of coasting control. It is a graph image figure of a coasting control determination map. It is a graph for demonstrating the fuel consumption reduction effect by coasting control. It is a graph of the accelerator opening actually measured in order to create a coasting control determination map, and clutch rotation speed. It is a flowchart which shows the procedure of the rotation speed setting at the time of coasting control in the coasting control apparatus of this invention. 4 is a timing chart from an accelerator operation to clutch engagement in a coasting control device to which the present invention is not applied. 4 is a timing chart from the accelerator operation to the clutch engagement in the coasting control device of the present invention. It is a flowchart which shows the procedure of the rotational speed setting at the time of coasting control in the conventional coasting control apparatus.

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

  As shown in FIG. 1, the coasting control device 1 according to the present invention includes a coasting control determination map 2 referred to by the clutch rotational speed and the accelerator opening, and the clutch rotational speed and the accelerator opening to the coasting control determination map 2. The plot point is within the coasting controllable region, the accelerator pedal operation speed is within the predetermined range, and the plot point of the clutch rotation speed and accelerator opening has passed the coasting control threshold line in the direction of decreasing accelerator opening. When it is determined that the engine is operating without working to the outside, the clutch is disengaged and the engine speed is reduced to the target engine speed to start coasting control. The coasting control execution unit 3 that terminates coasting control when it is out of the range or the plot point goes out of the coasting controllable region, and is determined by the clutch rotational speed when coasting control ends. The rotation matching control unit 4 that engages the clutch after increasing the engine speed to within the allowable contact range, and the target engine speed during coasting control is set between the clutch rotational speed and the idle rotational speed. And a setting unit 5.

  The coasting control determination map 2, the coasting control execution unit 3, the rotation alignment control unit 4, and the coasting control rotation speed setting unit 5 constituting the coasting control device 1 are preferably mounted on, for example, an ECU (not shown). .

  Each part is demonstrated about the vehicle carrying the coasting control apparatus 1 of this invention.

  As shown in FIG. 2, the vehicle clutch system 101 on which the coasting control device 1 of the present invention is mounted is a system in which a manual type and an automatic type by ECU control are compatible. A clutch master cylinder 103 mechanically coupled to the clutch pedal 102 supplies operating oil to an intermediate cylinder (also referred to as a clutch-free operating cylinder or a switching cylinder) 104 in accordance with a depression / return operation of the clutch pedal 102 by a driver. It is like that. On the other hand, a clutch-free actuator unit 105 controlled by an ECU (not shown) supplies hydraulic oil to the intermediate cylinder 104 in response to a clutch disengagement / contact command. The intermediate cylinder 104 supplies operating oil to the clutch slave cylinder 106. The piston 107 of the clutch slave cylinder 106 is mechanically connected to the movable part of the clutch 108.

  As shown in FIG. 3, the actuator 110 includes a clutch-free actuator 111. The clutch free actuator 111 includes an intermediate cylinder 104 and a clutch free actuator unit 105. The clutch free actuator unit 105 includes a solenoid valve 112, a relief valve 113, and a hydraulic pump 114. In the intermediate cylinder 104, a primary piston 116 and a secondary piston 117 are arranged in series. When the primary piston 116 is stroked by the operating oil from the clutch master cylinder 103, the secondary piston 117 is caused to stroke. . The intermediate cylinder 104 is configured such that the secondary piston 117 is stroked by the operating oil from the clutch-free actuator unit 105. Operating oil is supplied to the clutch slave cylinder 106 in accordance with the stroke of the secondary piston 117. With this configuration, when manual operation is performed, clutch disengagement / engagement is preferentially performed according to manual operation, and when manual operation is not performed, clutch disengagement / engagement according to ECU control is performed.

  The coasting control device of the present invention can also be applied to an automatic clutch system without a manual type.

  As shown in FIG. 4, the vehicle is provided with an ECU 121 that mainly controls a transmission and a clutch, and an ECM 122 that mainly controls an engine. The ECU 121 includes a shift knob switch, a transmission shift sensor, a select sensor, a neutral switch, a T / M rotation sensor, a vehicle speed sensor, an idle switch, a manual changeover switch, a parking brake switch, a door switch, a brake switch, a half-clutch adjustment switch, Input signal lines for the accelerator operation amount sensor, the clutch sensor, and the hydraulic switch are connected. Further, the ECU 121 is connected with output signal lines of a motor of the hydraulic pump 114 of the clutch system 101, a solenoid valve 112, a slope start assisting valve, and a warning & meter. Although not shown, various input signal lines and output signal lines used for engine control are connected to the ECM 122. The ECM 122 can transmit each signal of the engine speed, the accelerator opening, and the engine speed change request to the ECU 121 via a CAN (Controller Area Network) transmission path.

  The clutch rotational speed used in the present invention is the rotational speed on the driven side of the clutch, and is the same as the rotational speed of the input shaft of the transmission. The clutch rotational speed can be obtained from the input shaft rotational speed detected by an input shaft rotational speed sensor (not shown). Alternatively, the clutch rotational speed can be obtained from the vehicle speed detected by the vehicle speed sensor using the gear ratio of the current gear stage. The clutch rotational speed represents the engine rotational speed corresponding to the vehicle speed.

  Hereinafter, the operation of the coasting control device 1 of the present invention will be described.

  The operation concept of coasting control will be described with reference to FIG. However, here, the target engine speed during coasting control will be described as idle speed. The horizontal axis shows time and control flow, and the vertical axis shows engine speed. While the accelerator pedal 141 is largely depressed from the idling state and the accelerator opening degree continues to be 70%, the engine speed 142 increases and the vehicle is accelerated. Assume that a coasting control start condition described later is satisfied when the engine speed 142 is stabilized, the depression of the accelerator pedal 141 is reduced, and the accelerator opening is 35%. By starting coasting control, the clutch is controlled to be disengaged, and the engine speed 142 is controlled to the idle speed. The vehicle will run in coasting control. Thereafter, it is assumed that the accelerator pedal is no longer depressed and the accelerator opening becomes 0% or other coasting control end conditions are satisfied. When the coasting control ends, the engine is controlled to rotate and the clutch is controlled to contact. In this example, since the accelerator opening is 0%, the engine is braked and the vehicle is decelerated.

  If coasting control is not performed, the engine speed remains high as indicated by the broken line during the coasting control execution period, so that fuel is wasted, but coasting control is performed. Thus, during coasting control, the engine speed 142 becomes the idling speed and fuel is saved.

  FIG. 6 shows the coasting control determination map 2 as a graph image.

  The coasting control determination map 2 is a map in which the horizontal axis is the accelerator opening and the vertical axis is the clutch rotational speed. The coasting control determination map 2 can be divided into a minus region MA where the engine output torque is negative and a plus region PA where the engine output torque is positive. The minus region MA is a region where the engine friction is larger than the engine required torque and the engine output torque is negative. The positive region PA is a region where the engine output torque is positive because the engine required torque is larger than the engine friction. The engine output torque zero line ZL, which is the boundary between the minus area MA and the plus area PA, indicates that the engine does not work to the outside as described in the background art, and fuel is wasted.

  In the present embodiment, the coasting control threshold line TL is set slightly to the left of the engine output torque zero line ZL of the coasting control determination map 2 (on the side where the accelerator opening is small). In the coasting control determination map 2, a coasting controllable area CA having a finite width including the coasting control threshold line TL is set between the minus area MA and the plus area PA. In the coasting control determination map 2, a lower limit threshold line UL of the clutch rotational speed is set. The lower limit threshold line UL defines a lower limit threshold value of the clutch rotational speed regardless of the accelerator opening. The lower limit threshold line UL is set slightly above the clutch rotational speed in the idle state as shown in the figure.

The coasting control device 1 starts coasting control when all the following four coasting start conditions are satisfied.
(1) The accelerator pedal operating speed is within the threshold range. (2) In the coasting control determination map 2, the plot points of the clutch rotational speed and the accelerator opening pass the coasting control threshold line TL in the accelerator return direction. The plot point on the control determination map 2 is within the coasting controllable area CA. (4) In the coasting control determination map 2, the clutch rotational speed is equal to or greater than the lower limit threshold line UL.

The coasting control device 1 is configured to end coasting control when at least one of the following two coasting termination conditions is satisfied.
(1) The accelerator pedal operating speed is outside the threshold range. (2) The plot point on the coasting control determination map 2 is outside the coasting control possible area CA.

  The operation of the coasting control device 1 according to the coasting control determination map 2, the coasting start condition, and the coasting end condition will be described.

  The coasting control execution unit 3 constantly monitors the accelerator opening based on the accelerator pedal operation amount and the clutch rotational speed obtained from the input shaft rotational speed or the vehicle speed, and displays the accelerator opening on the coasting control determination map 2 of FIG. And plot the clutch rotation speed coordinate point. Coordinate points move over time. At this time, when the coordinate point exists in the coasting controllable area CA, the coasting control execution unit 3 determines whether or not to start coasting control. When the coordinate point does not exist in the coasting controllable area CA, the coasting control execution unit 3 does not determine whether to start coasting control.

  Next, when the coordinate point passes the coasting control threshold line TL in the direction in which the accelerator opening decreases, the coasting control execution unit 3 starts coasting control. That is, the coasting control device 1 controls the clutch to be disengaged and controls the control accelerator opening that the ECM 122 instructs the engine to correspond to the idle. As a result, the clutch is disengaged and the engine is in an idle state.

  As shown in FIG. 6 by the arrow indicating the moving direction of the coordinate point, the direction in which the accelerator opening decreases is the left direction in the figure. Even if the coordinate point passes the coasting control threshold line TL, if the movement direction of the coordinate point has a component in the right direction in the figure, the accelerator opening increases, so the coasting control execution unit 3 performs coasting control. Do not start.

  The coasting control execution unit 3 constantly monitors the accelerator opening and the clutch rotational speed even after starting coasting control, and plots the coordinate points of the accelerator opening and the clutch rotational speed on the coasting control determination map 2. When the coordinate point goes out of the coasting controllable area CA, the coasting control execution unit 3 ends the coasting control.

  With the above operation, when the accelerator pedal is operated to the depression side, coasting control is not started even if the coordinate point of the accelerator opening and the clutch rotational speed passes the coasting control threshold line TL, and the accelerator pedal is Since the coasting control is started when the coordinate point passes the coasting control threshold line TL only when operated on the return side, the driver does not feel uncomfortable.

  The coasting control execution unit 3 does not start coasting control when the coordinate point is below the lower limit threshold line UL (the clutch rotational speed is lower than the lower limit threshold). This is because even if the clutch is disengaged when the engine is in an idle state, many effects of suppressing fuel consumption cannot be expected. Therefore, coasting control execution unit 3 starts coasting control only when the coordinate point exists above the lower limit threshold line UL.

  The fuel consumption reduction effect by coasting control will be described with reference to FIG.

  First, it is assumed that coasting control is not performed. The engine speed changes in the range of 1600 to 1700 rpm from about 30 s to about 200 s, and decreases from about 1700 rpm to about 700 rpm (idle speed) between about 200 s and about 260 s. .

  The engine torque increases from about 30 s to about 100 s, but then starts to decrease and continues to decrease to about 150 s. The engine torque is about 0 Nm from about 150 s to about 160 s and increases between about 160 s and about 200 s, but becomes about 0 Nm at about 200 s. As a result, the period during which the engine torque is approximately 0 Nm is from about 150 s to about 160 s (ellipse B1), from about 200 s to about 210 s (ellipse B2), and from about 220 s to about 260 s (ellipse B3). is there.

  The fuel consumption (no vertical axis scale; for convenience, it is arranged so as to overlap with the engine torque) changes from about 50 s to about 200 s almost accompanying the transition of the engine torque. Even if the engine torque is approximately 0 Nm, the fuel consumption is not zero.

  Here, when coasting control is performed, the engine speed is controlled to the idle speed during a period in which the engine torque is approximately 0 Nm. The graph shows a line (thick solid line) of the engine speed during coasting control so as to be separated from a line (solid line) of the engine speed not performing coasting control. The coasting control was executed three times for ellipses B1, B2 and B3. The fuel consumption amount in the period when the coasting control is performed is lower than the fuel consumption amount when the coasting control is not performed, and it is understood that the fuel consumption is saved.

  Next, a specific setting example of the coasting control determination map 2 will be described.

  As shown in FIG. 8, in order to create the coasting control determination map 2, the characteristics of the accelerator opening and the clutch rotational speed are measured, the horizontal axis is the accelerator opening, and the vertical axis is the clutch rotational speed (= engine rotational speed). ; When the clutch is engaged). Thereby, the actually measured engine output torque zero line ZL can be drawn. The entire left side of the engine output torque zero line ZL is the minus region MA, and the entire right side is the plus region PA.

  A coasting control threshold line TL is defined and drawn slightly to the left of the engine output torque zero line ZL. A deceleration zero threshold line TLg is estimated and drawn slightly to the left of the coasting control threshold line TL. An acceleration zero threshold line TLk is estimated and drawn slightly to the right of the engine output torque zero line ZL. A region sandwiched between the deceleration zero threshold line TLg and the acceleration zero threshold line TLk is defined as a coasting controllable region CA. In this example, the lower limit threshold line UL is set to 880 rpm.

  The deceleration zero threshold line TLg and the acceleration zero threshold line TLk are set to such an extent that the driver is difficult to drive. However, since they are problems of human sense, they cannot be quantified by design, so they are tuned with an actual vehicle. The coasting control threshold line TL is set at the center of the deceleration zero threshold line TLg and the acceleration zero threshold line TLk.

  The graph of FIG. 8 created as described above is appropriately digitized (discretized) and written into the storage element, whereby the coasting control determination map 2 that can be used for the arithmetic processing by the coasting control execution unit 3 is obtained.

  Next, a procedure for setting the target engine speed VE in the coasting control device 1 of the present invention will be described with reference to FIG.

  When the coasting control execution unit 3 starts coasting control, the coasting control rotation speed setting unit 5 determines in step S91 whether the clutch disengagement control by coasting control is being performed. If no, go to the end. In the case of YES, the coasting control rotation speed setting unit 5 obtains the clutch rotation speed VC in step S92. The clutch rotational speed VC is an engine rotational speed corresponding to the current vehicle speed, and can be obtained from the input shaft rotational speed or can be obtained from the vehicle speed using the gear ratio of the current gear stage.

  Next, the coasting control rotation speed setting unit 5 obtains a difference dV between the clutch rotation speed VC and the idle rotation speed VI in step S92. The coasting control speed setting unit 5 sets the product of the difference dV and the predetermined value α as an offset value dV × α, and sets the sum of the offset value and the idle speed VI as the target engine speed VE. As a result, during the coasting control, the coasting control execution unit 3 controls the engine speed to the target engine speed VE. The predetermined value α is preferably set to an appropriate value by experiment.

  After that, when the accelerator pedal is depressed at a predetermined or higher accelerator pedal operation speed, the coasting control execution unit 3 ends the coasting control. Immediately after the coasting control is completed, the rotation matching control unit 4 starts the rotation matching control. In the rotation matching control, the engine speed that has been reduced to the target engine speed VE is increased, and the clutch is engaged when the engine speed falls within the allowable contact range determined by the clutch speed.

  The effect of the coasting control device 1 of the present invention will be described with reference to a comparison between FIG. 10 and FIG.

  As shown in FIG. 10, in the coasting control device to which the present invention is not applied, the engine speed is the idling speed during the coasting control (# 101) in which the clutch is disengaged (# 102). It is assumed that the coasting termination condition described above is satisfied when the accelerator pedal operation speed exceeds the threshold value and coasting control is terminated (# 103). Immediately, rotation matching is started (# 104), the control accelerator opening commanded by the ECM 122 to the engine is increased (# 105), and the engine speed is increased (# 106). When the engine speed matches the clutch speed (reaches within the allowable contact range) (# 107), clutch engagement is started (# 108). As a result, the clutch engagement is completed (# 109).

  In this timing chart, the time from coasting control end # 103 to clutch engagement completion # 109 (or the time from start of depression of the accelerator pedal to clutch engagement completion # 109) does not start the acceleration of the vehicle. It will be a free running time where you can feel free running.

  As shown in FIG. 11, in the coasting control device 1 of the present invention, during coasting control (# 111) in which the clutch is disengaged, the engine speed is higher than the idle speed by an offset value dV × α ( # 112). It is assumed that the coasting end condition described above is satisfied when the accelerator pedal operation speed exceeds the threshold value, and the coasting control is terminated (# 113). Immediately, rotation matching is started (# 114), the control accelerator opening degree commanded by the ECM 122 to the engine is increased (# 115), and the engine speed is increased (# 116). When the engine speed matches the clutch speed (reaches within the allowable contact range) (# 117), clutch engagement is started (# 118). As a result, the clutch engagement is completed (# 119).

  During the time from coasting control end # 113 to clutch engagement completion # 119 (or from the start of the accelerator pedal to clutch engagement completion # 119), the vehicle does not start accelerating, so the driver feels free running It will be a free running time. However, as compared with FIG. 10 drawn on the same scale, the engine rotation speed during coasting control is higher than the idle rotation speed, so that the time for performing rotation matching is shortened. For this reason, it can be seen that the idle running time is shortened.

  As described above, according to the coasting control device 1 of the present invention, the target engine speed at the time of coasting control is set between the clutch rotational speed and the idle rotational speed. The idle run time is shortened. As a result, the vehicle accelerates with high responsiveness, and the driver's uncomfortable feeling when entering acceleration from coasting control is reduced.

  According to the coasting control device 1 of the present invention, the target engine speed VE during coasting control is set to an offset value dV × α that is a product of a difference dV between the clutch rotational speed VC and the idle rotational speed VI and a predetermined value α. Since the engine speed is the sum of the idle speed VI, the higher the engine speed immediately before coasting control, that is, the higher the clutch rotational speed during rotation matching, the higher the engine speed during coasting control is controlled. Contributes to shortening the idle time.

  In the present invention, since the engine speed is higher than the idle speed during coasting control, the fuel consumption saving effect described with reference to FIG. 7 is slightly reduced. Therefore, the predetermined value α is preferably determined by a trade-off between the effect of shortening the idle running time and the effect of saving fuel consumption.

1 coasting control device 2 coasting control determination map 3 coasting control execution unit 4 rotation matching control unit 5 coasting control rotation speed setting unit

Claims (3)

A coasting control execution unit for starting coasting control by disengaging the clutch and lowering the engine speed to the target engine speed when the engine is operated without performing work on the outside;
A rotation matching control unit that engages the clutch after increasing the engine speed to within a contact allowable range determined by the clutch speed at the end of coasting control;
A coasting control device comprising: a coasting control speed setting unit that sets a target engine speed during coasting control between a clutch speed and an idle speed.   The coasting control rotational speed setting unit obtains a difference between the clutch rotational speed and the idle rotational speed, uses a product of the difference and a predetermined value as an offset value, and uses the sum of the offset value and the idle rotational speed as the target engine rotational speed. The coasting control device according to claim 1, wherein the coasting control device is a number. It has a coasting control determination map referred to by the clutch rotational speed and the accelerator opening,
The coasting control execution unit has a plot point of the clutch rotational speed and the accelerator opening to the coasting control determination map in the coasting controllable region, the accelerator pedal operation speed is within a predetermined range, and the clutch rotational speed When the accelerator opening plot point passes the coasting control threshold line in the accelerator opening decreasing direction, coasting control is started and the accelerator pedal operation speed is out of the specified range or the plot point is outside the coasting controllable area. The coasting control device according to claim 1 or 2, wherein the coasting control is ended when the coasting control is finished.

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