JP2814682B2 - Control device for automatic transmission for vehicles - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for performing a shift control of an automatic transmission in a vehicle such as an automobile and a control for reducing an engine output torque during a shift.

2. Description of the Related Art A conventional stepped automatic transmission includes a gear train mainly including a plurality of sets of planetary gear mechanisms and a plurality of engagement means such as clutches and brakes. It is well known that a plurality of gear ratios are set according to the state. In this type of automatic transmission, if the number of planetary gear mechanisms and the number of engagement means to be used are large, the power transmission path in the gear train can be more diversified, so that the number of shift stages that can be set is large. The planetary gear mechanism is not involved in the transmission of torque at all speeds.There is a planetary gear mechanism that does not contribute to the transmission of torque at any speed, or the gear ratio does not change. Since the torque transmission path can be changed, there are many examples in which there are a plurality of types of engagement / release combination patterns (engagement / release patterns) of the engagement means for setting any one of the gear positions. . Depending on the configuration of the gear train, such engagement / disengagement patterns include those in which the rotational state does not change at all and those in which the rotational speed of any of the rotating members (such as a sun gear, a ring gear, or a carrier) differs. Therefore, the manner of selecting the engagement / disengagement pattern affects the shift controllability and the like. That is, for example, when a shift is executed by selecting an engagement / disengagement pattern in which the above-mentioned variable rotation speed of the rotating member is increased, the shift shock is deteriorated due to an increase in the inertial force of the rotating member, and this is eliminated. For this reason, complicated shift control has to be performed, and conversely, if the above-mentioned engagement / disengagement pattern in which the rotating speed of the rotating member fluctuates is selected, engagement or disengagement is performed in executing the shift. When the number of engagement means for switching the state becomes three or more, it becomes difficult to appropriately control the timing of engagement and disengagement, in other words, shift control becomes difficult, or shift shock worsens. Sometimes.

Therefore, as described above, the present applicant has proposed a control device for an automatic transmission having a plurality of types of engagement / disengagement patterns for setting a predetermined gear position. By selecting an engagement / disengagement pattern in which the ratio of the number of revolutions before and after the shift is reduced, and performing the shift, the actual fluctuating speed or inertia force is reduced to reduce the shift shock, and conversely, the input shaft speed Is small, the actual fluctuating speed or inertia force does not increase even if the ratio of the number of rotations of the rotating member before and after shifting is increased, so that priority is given to avoiding so-called simultaneous shifting, A control device that selects an engagement / disengagement pattern in which the number of rotations increases in proportion to the speed is already proposed (Japanese Patent Application No. 2-6857).

Problems to be Solved by the Invention In automatic transmissions, it is important to reduce shocks during shifting, but shifting shocks are essentially caused by sudden torque fluctuations. Therefore, control for temporarily lowering the output torque of the engine during gear shifting is performed. This lowers the engine output torque by slightly delaying the ignition timing of the engine during or around the execution of the shift, or stopping or reducing the supply of fuel, and further causing misfiring in one of the cylinders, etc. As a result, the input torque of the automatic transmission is reduced to suppress the torque fluctuation appearing on the output shaft. When such output torque control of the engine is performed together with the above-described shift control by the control device according to the present applicant's proposal, a plurality of engagement / disengagement patterns selected based on the input shaft rotation speed and the like are provided. Since it is common to determine the amount of decrease in the output torque of the engine in accordance with one of the engagement / disengagement patterns, another engagement / disengagement pattern is selected for some reason, such as avoiding simultaneous shifting. Is executed, the amount of decrease in the output torque of the engine may be excessive or too small, and the shift shock may not be sufficiently reduced.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control device for an automatic transmission for a vehicle, which can reduce a shift shock by lowering an engine output torque in accordance with a shift situation. It is the purpose.

Means for Solving the Problems The present invention achieves the above object by the configuration shown in FIG. That is, the control device of the present invention
A gear train connected to the engine E, and a plurality of engaging means for setting the gear train to a plurality of shift speeds having different speed ratios according to an engaged / disengaged state. In the automatic transmission A for a vehicle, in which there are a plurality of types of patterns in which the number of rotations of any one of the rotating members in the gear train is different as a combination pattern of engagement and disengagement of the engagement means for setting, such as an engine load and a vehicle speed. A traveling condition detector 10 for detecting traveling conditions, and the traveling condition detector 10
Speed determining means 11 for determining a speed to be set based on data given from the CPU, and a plurality of types of the engaging means in which the speed determined by the speed determining means 11 is different from the rotational speed of the rotating member. A first combination pattern of engagement / disengagement of the engagement means and a variable rotation speed of the rotating member, in which the variable rotation speed of the rotating member is reduced when the shift speed is set by the combination pattern of engagement and release of the rotation member; And a second combination pattern of engagement / disengagement of the engagement means for increasing the engagement / release pattern selection means 12 based on predetermined conditions, and an engagement / disengagement pattern selected by the engagement / release pattern selection means 12 Gear position setting means 13 for outputting a command signal to the hydraulic control device C to set the gear position in accordance with the engagement / release pattern of the means;
When the first combination pattern of the release is selected, the decrease in the output torque of the engine E is reduced, and
And an engine output torque control means for increasing the output torque reduction amount of the engine when the second combination pattern of release is output.

Operation Therefore, in the present invention, the gear position determining means 11
Determines the gear position based on data provided from the traveling condition detector 10, and the engagement / release pattern selection device 12 selects a combination pattern of engagement / release of the engagement device for setting the gear position. . On the other hand, when the determined gear position is a gear position in which the rotational speed of the rotating member can be set in a plurality of combinations of engagement and disengagement patterns different from each other, the variable rotation speed of the rotating member is determined based on a predetermined condition. Either the first engagement / disengagement combination pattern in which the number is reduced or the second engagement / release combination pattern in which the rotating speed of the rotating member is increased is selected by the engagement / disengagement pattern selecting means 12. You. The gear position setting means 13 outputs the determined gear position in accordance with the selected combination pattern of engagement and disengagement.
Supplies hydraulic pressure to engage predetermined engagement means and releases pressure to release it from other predetermined engagement means. On the other hand, the engagement / disengagement pattern selection means 12 outputs a signal to the engine output torque control means 16,
Is selected, the engine output torque control means 16 performs control so as to reduce the output torque decrease amount of the engine E, and conversely, the second engagement / disengagement pattern is selected. When the release combination pattern is selected, the engine output torque control means 16 controls to increase the output torque decrease amount of the engine E. As a result, the control for reducing the output torque of the engine E at the time of shifting is performed without any excess or deficiency in accordance with the situation of shifting, so that deterioration of shift shock is prevented.

Embodiment Next, a description will be given based on an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of the present invention,
The automatic transmission A connected to the engine E is mainly composed of a plurality of sets of planetary gear mechanisms described below, and is configured to set a plurality of shift speeds by a combination of engagement and disengagement of a plurality of friction engagement means. Has columns. Further, a hydraulic control device C for supplying or discharging hydraulic pressure to the friction engagement means for setting each shift speed is provided.
For example, a hydraulic pump, a pressure regulating valve, a shift valve, a solenoid valve and the like, which are employed in a conventional general automatic transmission, can be used. An electronic control unit 20 is provided to control the output torque of the engine E and to control the hydraulic control device C to set each shift speed.
The input / output device 21 of the electronic control unit 20 includes:
A throttle opening sensor 22 which detects and outputs a throttle opening θ in the engine E, a vehicle speed sensor 23 which detects a turbine speed or an output shaft speed in the automatic transmission A and outputs it as a vehicle speed V, and an automatic transmission A rotation speed sensor 24 for detecting and outputting the rotation speed of a predetermined rotation element such as an input shaft of A is connected.

On the other hand, the electronic control unit 20 has a first memory 25 in which information for setting the gear position is stored, and a second memory 26 in which information for controlling the amount of decrease in the output torque of the engine E is stored. And an arithmetic unit (CPU) 27. The first memory 25 stores a shift diagram that determines a shift speed using the vehicle speed V and the throttle opening θ as parameters and a combination pattern (engagement / disengagement) of friction engagement means for setting each shift speed. The second memory 26 stores, for example, two types of output torque reduction amounts corresponding to the throttle opening θ, and this is represented, for example, by the diagram of FIG.

When signals are input to the input / output device 21 from the sensors 22, 23, and 24, a calculation is performed by the calculation device 27 based on these signals and the information stored in the first memory 25, and the setting is performed. The shift speed to be set is determined, and an engagement / disengagement pattern for setting the shift speed is selected. In this case, as the engagement / disengagement pattern for setting the determined shift speed, a plurality of engagement / disengagement patterns in which the rotation speed of any of the rotating members (sun gear, ring gear, carrier, etc.) in the gear train is different from each other. If so, a different engagement / disengagement pattern is selected according to the rotation speed detected by the rotation speed sensor 24. That is, if the detected rotation speed is larger than a predetermined reference value, an engagement / disengagement pattern in which the variable rotation speed of the rotating member in the gear train is reduced is selected, and if the detected rotation speed is smaller than the reference value,
An engagement / disengagement pattern in which the rotational speed of the rotating member in the gear train increases is selected. The details will be described later.

The arithmetic unit 27 also stores input data and a second memory.
Based on the information stored in 26, the amount of reduction in engine output torque during gear shifting is calculated. That is, for example,
When the rotation speed detected by the rotation speed sensor 24 is low and the driving condition is such that the engagement / disengagement pattern in which the variable rotation speed of the rotating member is increased is selected, the output torque reduction amount ΔT during gear shifting is determined. The running is controlled as indicated by the line I in FIG. 3, and the engagement / disengagement pattern is selected such that the rotation speed detected by the rotation speed sensor 24 is large and the variable rotation speed of the rotating member is small. Under the conditions, the output torque reduction amount ΔT during the shift is controlled as shown by the line II in FIG.

The selected engagement / disengagement pattern is an input / output device.
21 to output a command signal to the hydraulic control device C. As a result,
The setting is made by supplying and discharging hydraulic pressure to a predetermined friction engagement means. In addition, engine output torque reduction control
For example, it is executed by performing a retard control of the ignition timing by a signal output from the input / output device 21 to the engine E.

Here, an example of the gear train in the automatic transmission A is shown in FIG. 4, and the example shown here mainly includes three sets of single pinion type planetary gear mechanisms 1, 2, and 3, The respective elements in the planetary gear mechanisms 1, 2, and 3 are connected as follows. That is, the first planetary gear mechanism 1
The carrier 1C and the ring gear 3R of the third planetary gear mechanism 3 are connected so as to rotate integrally, and the ring gear 2R of the second planetary gear mechanism 2 and the carrier 3C of the third planetary gear mechanism 3 are integrally formed. It is connected so that it turns. The sun gear 1S of the first planetary gear mechanism 1 is connected to the carrier 2C of the second planetary gear mechanism 2 via the second clutch means K2, while the sun gear of the second planetary gear mechanism 2 is connected via the fourth clutch means K4. 2S, and the carrier 2C of the second planetary gear mechanism 2 is connected to the third
It is connected to the sun gear 3S of the planetary gear mechanism 3.

In addition, as a connection structure of the above-described components, a connection structure employed in a general automatic transmission such as a hollow shaft, a solid shaft, or an appropriate connecting drum can be employed.

The input shaft 4 is connected to an engine (not shown) via a power transmission means (not shown) such as a torque converter and a fluid coupling, and the input shaft 4 and the ring gear 1R of the first planetary gear mechanism 1 are connected to each other. In between, the first to selectively connect the two
A clutch means K1 is provided, and a third clutch means K3 for selectively connecting the input shaft 4 and the sun gear 1S of the first planetary gear mechanism 1 is provided between the input means 4 and the sun gear 1S.

The fourth clutch means K4 of the first to fifth clutch means K1 to K5 is constituted by a one-way clutch 20 and a multi-plate clutch 22 which are in parallel with each other, and the other clutch means are It is constituted by a multi-plate clutch. In addition, in practical use, there is a restriction on the arrangement of each constituent member, so that an appropriate intermediate member such as a connecting drum can be interposed as a connecting member for each clutch means K1, K2, K3, K4, K5. is there.

In addition, the third planetary gear mechanism 3 serves as brake means for preventing rotation of the rotating members in the planetary gear mechanisms 1, 2, and 3 described above.
A first brake means B1 for selectively preventing rotation of the sun gear 3S, a second brake means B2 for selectively preventing rotation of the carrier 2C of the second planetary gear mechanism 2, and a sun gear of the second planetary gear mechanism 2. Third brake means B3 for selectively preventing the rotation of 2S is provided. Among these brake means, the first brake means B1 includes a one-way clutch 40 provided between the sun gear 3S of the third planetary gear mechanism 3 and a transmission case (hereinafter simply referred to as a case) 6, and a one-way clutch 40. A second brake means B2 is provided in one direction provided between the carrier 2C of the second planetary gear mechanism 2 and the case 6 or an integral part thereof. It comprises a clutch 60 and a multiple disc brake 61 arranged in parallel with the one-way clutch 60, and the third brake means B3 is constituted by a band brake. In practical use, an appropriate connecting member may be interposed between the brake means B1, B2, B3 and each element to be fixed by the brake means B1, B2, B3 or the case 6. Of course.

An output shaft 5 for transmitting rotation to a propeller shaft and a counter gear (not shown) is connected to a ring gear 2R of the second planetary gear mechanism 2 and a carrier 3C of the third planetary gear mechanism 3 connected to each other. ing.

Further, the input shaft 4 is provided with a rotation speed sensor 24, and the output shaft 5 is provided with the aforementioned vehicle speed sensor 23.

In the automatic transmission A described above, five forward speeds and one reverse speed are defined as main gear speeds, and so-called 2.2 speeds, 2.5 speeds, and 2.7 speeds are provided between the second speed and the third speed. It is possible in principle to set 10 forward speeds and 1 reverse speed by adding so-called 3.2th and 3.5th speeds between the third forward speed and the fourth forward speed. In other gears except the 2.2nd, 2.7th, 3.2th, and 3.5th gears, a combination of engagement and disengagement of the clutch means and the brake means for setting the gear (the so-called engagement There are a plurality of combinations / release patterns, which are shown in Table 1 as an operation table.
Further, Table 2 shows the rotation speeds of the rotation elements of the planetary gear mechanisms 1, 2, and 3 in the respective engagement / disengagement patterns, as ratios when the rotation speed of the input shaft 4 is "1". In Table 1, a circle indicates that the vehicle is engaged, a blank indicates that the vehicle is released, and an asterisk indicates that the vehicle may be engaged. The gear ratio and the rotation state do not change even when released, such as the five-clutch means K5 and the first brake means B1, but if the clutch is released like the first brake means B1 in the pattern in the column b of the fourth speed, The gear ratio does not change, but the rotation state changes. The fourth clutch means K4 and the third brake means B3 in the pattern of the second speed column b.
As long as the other means marked with * are engaged, the gear ratio and the rotation state do not change even if released. In Tables 1 and 2, the 2nd speed, 3rd speed, 4th speed
In the columns labeled a, b, c,... In the speed, the fifth speed, and the reverse speed, the rotational speeds of the rotating elements of the planetary gear mechanism in the engagement / disengagement patterns for setting the speed are different. It indicates that it is an engagement / disengagement pattern,
.. Represent the types of the engagement / disengagement patterns although the rotation speeds of the rotating elements of the planetary gear mechanism are not different.

The gears shown in Table 1 are mainly selected by the electronic control unit 20 based on running conditions such as the vehicle speed V and the throttle opening θ, and the shift to the selected gear is performed by the electronic control unit 20. And outputs a signal to the hydraulic control device C, based on which the hydraulic control device C supplies and discharges hydraulic pressure to and from the friction engagement means in the automatic transmission A. Output torque reduction control is performed. In this case, in the automatic transmission A described above, when setting a shift speed having a plurality of types of engagement / disengagement patterns, different engagement / disengagement patterns are selected in accordance with a signal input from the rotation speed sensor 24. You. Specifically, when the driving condition for shifting to the fifth speed is satisfied in a state where the third speed is set in the engagement / disengagement pattern in the column d of Table 1, the rotation speed detected by the rotation speed sensor 24 is set. If the number is smaller than the reference value, the engagement / disengagement pattern of the fifth speed column b or c column in Table 1 is selected as the engagement / disengagement pattern for setting the fifth speed. This shift is the first
As can be seen from the table, this is achieved by releasing the first brake means B1 and engaging the third brake means B3, or releasing the first clutch means K1 and engaging the third brake means B3. Therefore, the so-called simultaneous shifting is not performed, and the control of the hydraulic pressure is facilitated. On the other hand, the rotation speed of the sun gear 3S of the third planetary gear mechanism 3 is reduced to the second
As shown in the table, the rotation speed changes from “0.00” to “2.40”, or the rotation speed of the ring gear 1R of the first planetary gear mechanism 1 becomes “1.0”.
From "0" to "2.41", the variable rotation speed increases.

On the other hand, when the rotation speed detected by the rotation speed sensor 24 is larger than the reference value, the engagement / disengagement pattern for setting the fifth speed is determined by the engagement / disengagement in the column a of the fifth speed in the first table. A release pattern is selected. As is apparent from Table 1, this shift is achieved by disengaging the first clutch means K1 and the first brake means B1 and engaging the third brake means B3, which is a so-called simultaneous shift. However, the maximum rotational speed of the rotating member is from "1.00" to "1.8" when the rotational speed of the ring gear 1R of the first planetary gear mechanism 1 is changed.
It is about 3 ", and the fluctuating rotation speed accompanying the shift can be suppressed to a small value.

The automatic transmission A selects an engagement / disengagement pattern in which the rotation speed of any one of the rotating members varies greatly depending on the input shaft rotation speed. Therefore, the engine output torque of the engine output torque is changed in accordance with the selected engagement / release pattern. The amount of reduction is controlled so as to change to a large or small amount. This will be specifically described with reference to the example of the shift from the third speed to the fifth speed as described above.
When the above-mentioned engagement / disengagement pattern in the column b or the engagement / disengagement pattern in the column c is selected as the release pattern, the rotational speed of the rotating members constituting the gear train becomes large, so that the engine E Is greatly reduced, for example, as shown by the line I in FIG. On the other hand, when the engagement / disengagement pattern in the column a described above is selected as the engagement / disengagement pattern for setting the fifth speed, the variable rotation speed of the rotating members constituting the gear train becomes small. The output torque of the engine E is reduced slightly, for example, as shown by the line II in FIG.

The shift control from the third speed to the fifth speed and the control for reducing the engine output torque described above will be described below with reference to the flowchart of FIG. First step 1
In step 2, various data such as the throttle opening θ, the vehicle speed V, and the input shaft speed ni are input, and the target gear is calculated and determined based on the running conditions such as the throttle opening θ and the vehicle speed V (step 2). ). It is determined whether or not the shift to the shift stage determined in this way is from the third speed to the fifth speed (step 3). If the determination result is “yes”,
It is determined whether the input shaft rotation speed ni is smaller than a predetermined reference value Ni (step 4). The result is “yes”
Then, the engagement / release pattern (5-b or 5-c) in the column b or c of Table 1 is selected as the engagement / release pattern for setting the fifth speed, and the third An output is made to change the engagement / disengagement pattern (3-d) in the d column where the speed is set to the engagement / disengagement pattern of (5-b) or (5-c) (step 5). Then, control is performed to reduce the output torque of the engine E as shown by the line I in FIG. 3 (step 6). That is, the engine E
, The amount of retard of the ignition timing is increased.

If the determination result of step 4 is “NO”, that is, if the input shaft rotation speed ni is equal to or more than the reference value Ni,
As the engagement / disengagement pattern for setting the fifth speed, the engagement / disengagement pattern (5-a) in column a of Table 1 described above is selected, and the engagement / disengagement pattern in column d for setting the third speed is set. An output is made to change the release pattern (3-d) to the engagement / release pattern of (5-a) (step 7). And in this case, since the fluctuating rotation speed of the rotating member in the gear train becomes small,
Control is performed to reduce the output torque of the engine E as indicated by the line II in FIG. 3 (step 8).

If the result of the determination in step 3 is “no”,
Proceeding to step 9, it is determined whether the shift is from the third speed to the fourth speed.

Therefore, in the above-described control device, the amount of reduction in the output torque of the engine E during the speed change depends on the magnitude of the variable rotation speed of the rotating member in the gear train, so that the speed change is performed smoothly.

In the above embodiment, the case where the speed is changed from the third speed to the fifth speed is described as an example. However, the present invention selects a plurality of engagement / disengagement patterns having different rotation speeds of the rotating members of the gear train. The present invention can be applied to the case where the shift is performed by changing the speed, and can be effectively applied to other than the shift between the shift speeds shown in the above-described embodiment. An automatic transmission according to the present invention includes an automatic transmission including a gear train having a plurality of engagement / disengagement patterns having different rotation speeds of rotating members as engagement / disengagement patterns for setting a predetermined gear position. Therefore, the present invention is not limited to the one shown in FIG. Other examples of this type of automatic transmission include, for example, Japanese Patent Application No. 1-185151, Japanese Patent Application No. 1-185152, and Japanese Patent Application No.
186991, Japanese Patent Application No. 1-186999, Japanese Patent Application No. 1-205478,
Examples of each configuration described in the specification and drawings such as Japanese Patent Application No. 1-280957 can be cited.

Further, in the above-described embodiment, the control for reducing the engine output torque is performed by increasing the retardation of the ignition timing. However, the present invention is not limited to the above-described embodiment. For example, the engine output torque is reduced by reducing the fuel injection amount. The torque reduction control may be performed, or may be performed by causing a misfire in any of a plurality of cylinders.

Advantageous Effects of the Invention As is apparent from the above description, according to the present invention, the output torque of the engine is reduced according to the magnitude of the fluctuating rotation speed of the rotating member according to the selection of the engagement / disengagement pattern for setting the gear position. Since the amount is controlled, the output torque of the engine during the shifting process does not become excessively large or small. As a result, it is possible to perform a smooth shifting with little shift shock.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of the present invention, FIG. 2 is a block diagram showing a configuration of an embodiment of the present invention, and FIG. 3 is a diagram showing a reduction amount of an engine output torque, a throttle opening, and the like during gear shifting. FIG. 4 is a skeleton diagram showing an example of a gear train, and FIG. 5 is a flowchart showing a control routine in the present invention. 1,2,3 ... Planetary gear mechanism, 1S, 2S, 3S ... Sun gear, 1C, 2
C, 3C Carrier, 1R, 2R, 3R Ring gear, 4 Input shaft, 5 Output shaft, 10 Running condition detector, 11 Shift speed determining means, 12 Disengagement Pattern selection means, 13 ...
... gear speed setting means, 14 ... engine output torque control means, 20 ... electronic control unit, 22 ... throttle opening degree sensor, 23 ... vehicle speed sensor, 24 ... rotation speed sensor, 25,26 ... memory, 27 ... Calculator, A ...
Automatic transmission, C: hydraulic control device, E: engine.

Continuation of the front page (56) References JP-A-2-92747 (JP, A) JP-A-3-213758 (JP, A) JP-A-2-256960 (JP, A) JP-A-3-181670 (JP) , A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60K 41/00-41/28 F02D 29/00-29/06 F16H 61/00

Claims (1)

(57) [Claims] A gear train connected to an engine; and a plurality of engaging means for setting the gear train to a plurality of gears having different speed ratios according to an engaged / released state. In an automatic transmission for a vehicle having a plurality of types of patterns in which the number of rotations of any one of the rotating members in the gear train is different as a combination pattern of engagement and disengagement of the engagement means for setting the gear stage, A traveling condition detector that detects traveling conditions such as a vehicle speed, and a gear position determining unit that determines a gear position to be set based on data provided from the traveling condition detector,
When the speed determined by the speed determining means is a speed set by a plurality of types of engagement / disengagement combination patterns of the engagement means having different rotational speeds of the rotating member, A first combination pattern of engagement / disengagement of the engagement means having a reduced variable rotation speed and a second combination pattern of engagement / disengagement of the engagement means having a large variable rotation speed of the rotating member are defined by predetermined conditions. Engagement / disengagement pattern selection means for selecting a gear position based on the engagement / disengagement pattern selection means, and a gear position setting means for outputting a signal to set a gear position with an engagement / release pattern of the engagement means selected by the engagement / release pattern selection means; The output torque reduction of the engine is reduced when the first combination pattern of engagement / disengagement is selected, and the output torque of the engine is reduced when the second combination pattern of engagement / disengagement is output. Control apparatus for a vehicular automatic transmission, characterized in that it comprises an engine output torque control means for increasing the reduction amount.