JPH0626373A - Control device for vehicle with automatic transmission - Google Patents

Abstract

PURPOSE:To provide a control device for vehicle with automatic transmission that will not increase an engine brake force suddenly toward the stoppage of a vehicle even if fuel cut control is carried out not to give an uneasy feeling to a driver. CONSTITUTION:In a state in which it is judged that the fuel cut control of an electronic control device for engine control 160 is in operation, a solenoid stop valve is operated by an electronic control device for transmission control 162 through the electronic control device for engine control 160 so that a target reverse drive torque-Te deg. calculated based on the vehicle speed V and transmission speed ratio gamma1 of a CVT14 during the fuel cut control can be obtained. Therefore, even if the transmission speed ratio gamma is changed to the maximum value gammamax before stoppage of the vehicle during the fuel cut control, in the course of the change, the target reverse drive torque Te deg. can be obtained and an engine brake force is optimized to a desired value to relive it more than before.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vehicle equipped with an automatic transmission, and more particularly to a technique for eliminating an uncomfortable feeling caused by excessive engine braking during deceleration of the vehicle.

[0002]

2. Description of the Related Art An automatic transmission capable of changing the speed of an engine and transmitting it to driving wheels and automatically changing a gear ratio, a throttle valve opening of substantially zero, and a predetermined engine speed. A fuel cut control device that shuts off fuel supplied to the engine when the fuel cut rotation speed is higher than the fuel cut rotation speed, and a gear ratio of the automatic transmission according to a decrease in vehicle speed when the throttle valve opening is substantially zero. There is known a vehicle control device including a gear ratio control device that changes the gear ratio to a deceleration side. According to such a device, when the vehicle is decelerated while the accelerator pedal is released, the gear ratio of the automatic transmission is controlled so that the engine rotation speed exceeds the predetermined fuel cut rotation speed.
The fuel cut region is expanded and suitable fuel economy is obtained. For example, it is the control device described in Japanese Patent Laid-Open No. 58-200843.

[0003]

By the way, according to the above conventional control device, in order to obtain the driving force when the vehicle restarts, it is necessary to change the gear ratio to the maximum value before the vehicle stops. Therefore, the vehicle braking force due to the reverse drive torque of the engine during the fuel cut control, that is, the engine braking force rapidly increases toward the stop of the vehicle, which causes the driver to feel uncomfortable.

The present invention has been made in view of the above circumstances, and an object thereof is that the engine braking force does not rapidly increase toward the stop of the vehicle even if the fuel cut control is performed, and the driver An object of the present invention is to provide a control device for a vehicle equipped with an automatic transmission that does not give a feeling of strangeness.

[0005]

The gist of the present invention for achieving the above object is to change the rotation of an engine to drive wheels as shown in the gist of the invention of FIG. An automatic transmission that transmits and can automatically change the gear ratio, and is supplied to the engine when the throttle valve opening is substantially zero and the engine rotation speed is higher than a predetermined fuel cut rotation speed. A vehicle provided with a fuel cut control device for shutting off fuel and a gear ratio control device for changing the gear ratio of the automatic transmission to a deceleration side in accordance with a decrease in vehicle speed when the throttle valve opening is substantially zero. Of the control device of (a) the fuel cut control device for determining whether or not the fuel cut control device is operating, and (b) the engine braking force generated prior to the stop of the vehicle. So that the target reverse drive torque calculation means calculates the target reverse drive torque based on at least the gear ratio of the automatic transmission, and (c) the rotational resistance of the engine in the state where the fuel to the engine is cut off. And (d) during the operation of the fuel cut control device, the rotational resistance control means for operating the rotational resistance adjustment means so as to obtain the target reverse drive torque. is there.

[0006]

With this configuration, in the state where the fuel cut control means determines that the fuel cut control device is operating, at least the engine braking force generated prior to the stop of the vehicle becomes a desired value. The rotation resistance control means operates the rotation resistance adjustment means so that the target reverse drive torque calculated by the target reverse drive torque calculation means is obtained based on the gear ratio of the automatic transmission.

[0007]

As a result, during fuel cut control, even if the gear ratio is changed to the maximum value before stopping the vehicle in order to obtain the driving force when the vehicle restarts,
In this process, since the rotation resistance adjusting means is operated so as to obtain the target reverse drive torque calculated based on at least the gear ratio of the automatic transmission, the engine braking force is set to a desired value, and the engine braking force is set to a desired value. Is also alleviated, so that the driver does not feel uncomfortable.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 2, in the vehicle, the power of the engine 10 is a fluid coupling 12 with a lockup clutch, a belt type continuously variable transmission (hereinafter referred to as CVT) 1.
4, the forward / reverse switching device 16, the intermediate gear device 18, and the drive gear 2 connected to the drive shaft 22 via the differential gear device 20.
4 is transmitted.

The fluid coupling 12 includes a pump impeller 28 connected to a crankshaft 26 of the engine 10 and a CVT 1.
4, a turbine impeller 32 fixed to the input shaft 30 and rotated by oil from the pump impeller 28, a lockup clutch 36 fixed to the input shaft 30 via a damper 34, and an engagement side oil passage 33L. The engagement side oil chamber 33 connected and the release side oil chamber 3 connected to the release side oil passage 35R.
5 and. The inside of the fluid coupling 12 is constantly filled with hydraulic oil. For example, when the vehicle speed exceeds a predetermined value,
Alternatively, when the rotational speed difference between the pump impeller 28 and the turbine impeller 32 becomes equal to or less than a predetermined value, the working oil is supplied to the engagement side oil chamber 33 and the working oil flows out from the release side oil chamber 35. The lockup clutch 36 is engaged and the crankshaft 26 and the input shaft 30 are directly connected. On the contrary, when the vehicle speed becomes less than or equal to the predetermined value, or when the rotation speed difference becomes greater than or equal to the predetermined value, the release side oil chamber 3
5 is supplied with hydraulic oil and the hydraulic oil is discharged from the engagement side oil chamber 33, so that the lock-up clutch 3
6 is released.

The CVT 14 is equipped with variable pulleys 40 and 42 of the same diameter provided on the input shaft 30 and the output shaft 38 thereof, respectively, and a transmission belt 44 wound around the variable pulleys 40 and 42. Variable pulley 40
And 42 are fixed rotary bodies 46 and 48 fixed to the input shaft 30 and the output shaft 38, respectively, and movable bodies provided on the input shaft 30 and the output shaft 38, respectively, so as to be movable in the axial direction and non-rotatable around the shaft. Rotating bodies 50 and 52
The movable rotary bodies 50 and 52 are moved by the primary side hydraulic cylinder 54 and the secondary side hydraulic cylinder 56 that function as hydraulic actuators, thereby changing the V groove width, that is, the hanging diameter (effective diameter) of the transmission belt 44. Thus, the gear ratio γ of the CVT 14 (= rotational speed N _in of the input shaft 30 / rotational speed N _out of the output shaft 38) is automatically changed.

The forward / reverse switching device 16 is a well-known double-pinion type planetary gear mechanism, and a pair of planetary gears 62 and 64 are rotatably supported by a carrier 60 fixed to an output shaft 58 of the planetary gear mechanism and mesh with each other. A sun gear 66 that is fixed to the input shaft (output shaft of the CVT 14) 38 of the forward / reverse switching device 16 and that meshes with the planet gear 62 on the inner circumference side; and a ring gear 6 that meshes with the planet gear 64 on the outer circumference side.
8, the reverse brake 70 for stopping the rotation of the ring gear 68, the carrier 60, and the forward / reverse switching device 16
And a forward clutch 72 that connects the input shaft 38 of FIG. Reverse brake 70 and forward clutch 72
Is a friction engagement device of the type that is hydraulically actuated, and when they are not engaged together, the forward / reverse switching device 1
6 is brought to a neutral state and power transmission is cut off. But,
When the forward clutch 72 is engaged, the output shaft 38 of the CVT 14 and the output shaft 58 of the forward / reverse switching device 16 are directly connected to each other to transmit power in the vehicle forward direction. When the reverse brake 70 is engaged, the rotational direction is reversed between the output shaft 38 of the CVT 14 and the output shaft 58 of the forward / reverse switching device 16, so that power in the reverse direction of the vehicle is transmitted.

The hydraulic control circuit 78 is disclosed in, for example, Japanese Patent Laid-Open No. 4-
The configuration is similar to that described in Japanese Patent No. 125354, and a first solenoid valve 80 for switching the shift direction of the CVT 14, a second solenoid valve 82 for controlling the shift speed of the CVT 14, and a lockup. A third solenoid valve 84 and a fourth solenoid valve 86 for controlling engagement and disengagement of the clutch 36, and a fifth solenoid valve 88 for controlling a second line pressure which is a tension control pressure of the transmission belt 44 are provided. A manual valve (not shown) that selectively operates the reverse brake 70 and the forward clutch 72 in association with the operation of the shift lever 90 is provided.

The CVT 14 has an input shaft rotational speed sensor 92 for detecting the rotational speed N _in of the input shaft 30,
An output shaft rotation speed sensor 94 for detecting the rotation speed N _out of the output shaft 38 is provided. The shift lever 90 is provided with an operation position sensor 96 for detecting its operation position P _s . Also, the engine 1
The 0, the engine rotational speed sensor 102 for detecting the rotational speed N _e of the engine 10 is provided, the intake pipe 104 of the engine 10, the intake air quantity Q
An air flow meter 106 for detecting the above, a throttle valve 108, a throttle sensor 110 for detecting the opening degree θ _th thereof, and a fuel injection valve 112 are respectively provided. A vehicle speed sensor 114 for detecting the vehicle speed V is provided near the output shaft 58.

The engine 10 is provided with a rotation resistance adjusting device 118 for adjusting the pumping loss of the engine 10 in the fuel cut state, that is, the rotation resistance. As shown in detail in FIG. 3, the engine 10 includes a cylinder block 122 in which a piston 120 is fitted, a cylinder head 124 fixed to one end of the cylinder block 122, and an intake valve 128 for opening and closing an intake port 126. And an exhaust valve 132 for opening and closing the exhaust port 130, and the intake pipe 104 is connected to the cylinder head 124 so as to communicate with the intake port 126. The rotation resistance adjusting device 118 includes an escape passage 140 provided in the cylinder head 124 so as to communicate with the combustion chamber 138, and an electromagnetic opening / closing valve 142 that opens and closes the escape passage 140. The solenoid opening / closing valve 142 has a hole 146 for communicating with the valve chamber 144 and the escape passage 140.
A valve 148 that opens and closes the valve 148, an electromagnetic solenoid 150 that drives the valve 148, and a spring 152 that urges the valve 148 in the valve closing direction.
And a return port 156 provided in the intake pipe 104 are connected by a return line 158.

When the electromagnetic opening / closing valve 142 is driven at a predetermined duty ratio α during the fuel cut control, a gas having a flow rate according to the duty ratio α is generated in the combustion chamber 1.
Since it is escaped from 38 to the intake pipe 104, the engine 1
The rotation resistance of 0 is reduced according to the duty ratio α.

Returning to FIG. 2, the engine control electronic control unit 160 provides the throttle sensor 110 with a signal indicating the intake air amount Q detected by the airflow meter 106.
The detected signal representing the throttle valve opening theta _th, a signal indicative of engine rotational speed N _e detected by the engine speed sensor 102, such as a signal representing the vehicle speed V detected by the vehicle speed sensor 114 is supplied by There is. The engine control electronic control unit 160 includes a CPU, R
The CPU is a so-called microcomputer including an AM, a ROM, an input / output interface circuit, etc. The CPU processes an input signal according to a program stored in advance in the ROM while utilizing the temporary storage function of the RAM, and adjusts the fuel injection valve 112 and the rotation resistance. The device 118 and the like are controlled.

For example, the engine control electronic control unit 1
In the fuel injection control at 60, the engine speed N _e
And the basic injection time is calculated from the intake air amount Q, and the optimum injection time is calculated by adding the correction based on the signal from each sensor to the fuel injection so that the fuel is injected at this optimum injection time. The valve 112 is driven.

The engine control electronic control unit 160 is also provided.
In the fuel cut control in (1), the engine speed N _e is set to a value of about 1200 r.pm, for example, during the coasting in which the throttle valve opening θ _th is substantially zero within the predetermined vehicle speed range of the vehicle. When the rotation speed N _cut is exceeded, the fuel injection valve 112 is closed and the fuel supply to the engine 10 is cut off in order to improve fuel economy. Then, the engine control electronic control unit 160 outputs a signal F _cut indicating that the fuel cut control is being performed.
Is output to the electronic control unit 162 for gear shift control, while the electronic control unit 1 for gear shift control is performed during the fuel cut control.
The rotation resistance adjusting device 118 is operated so as to generate the rotation resistance of the engine 10 corresponding to the signal R _res supplied from 62.

The shift control electronic control unit 162 includes an input shaft rotation speed sensor 92 and an output shaft rotation speed sensor 94.
Of the input shaft rotation speed N _in and the output shaft rotation speed N _out detected by the engine rotation speed sensor 102, the signal indicating the operation position P _s of the shift lever 90 detected by the operation position sensor 96, and the engine rotation speed sensor 102 detected by A signal representing the rotation speed N _e of the engine 10, the throttle sensor 11
A signal representing the throttle valve opening θ _th detected by 0,
A signal indicating the vehicle speed V detected by the vehicle speed sensor 114 is supplied. Electronic control unit 16 for shift control
2 is also a so-called microcomputer including a CPU, a RAM, a ROM, an input / output interface circuit, and C
The PU processes the input signal in accordance with a program stored in advance in the ROM while utilizing the temporary storage function of the RAM, and controls the gear ratio by the first solenoid valve 80 and the second solenoid valve 8
2. The third solenoid valve 84 and the fourth solenoid valve 86 for controlling the lockup clutch 36, and the fifth solenoid valve 88 for controlling the second line pressure are respectively driven.

For example, the electronic control unit 162 for shift control
In the gear shift control in (1), the gear shift diagram corresponding to the operation position P _s of the shift lever 90 (for example, the upper half portion of FIG. 4) is selected from a plurality of pre-stored gear shift diagrams, and the actual vehicle speed is selected from the gear shift diagram. The target input shaft rotation speed N _in ° (that is, target engine rotation speed N _e °) is determined based on V and the throttle valve opening θ _th , and the target input shaft rotation speed N is determined.
speed ratio of the CVT 14 gamma is controlled so _in DEG actual input shaft rotational speed N _in the (i.e. the actual engine rotational speed N _e) match. The above-mentioned shift diagram is obtained in advance so that fuel economy and drivability are compatible with each other. Also,
In this shift control, during fuel cut control, the period during which the engine rotation speed N _e exceeds the fuel cut rotation speed N _cut is as long as possible, in other words, the operating range of the fuel cut control is expanded. Then, the gear ratio is controlled. That is, in the state where the fuel cut control is executed in the coasting state in which the accelerator pedal is returned and the throttle opening θ _th becomes substantially zero,
As shown in, the target rotation input shaft speed N _in ° is initially decreased along the line of γ _min as the vehicle speed V decreases, but when it falls below a predetermined vehicle speed V ₁ , the fuel cut rotational speed N It is fixed to the target rotation input shaft speed N _inf ° during the fuel cut control set slightly higher than _cut , and the actual input shaft rotation speed N _in is equal to the target rotation input shaft speed N _inf ° during the fuel cut control. The gear ratio γ is rapidly changed toward the maximum gear ratio γ _max so as to coincide with each other.

As described above, in the process in which the gear ratio γ is rapidly changed prior to the stop of the vehicle, there is no feeling of idling as compared with a vehicle equipped with a conventional automatic transmission (so-called A / T).
As shown in the lower half line J in FIG. 4, a relatively large engine braking action occurs and gives the driver a feeling of strangeness. Therefore, in the present embodiment, the rotational resistance of the engine 10 is relaxed in the above process. The engine brake mitigation control for eliminating the discomfort is performed by the electronic control unit 16 for shift control.
2 is executed. Hereinafter, the engine brake mitigation control will be described with reference to the flowchart of FIG.

In step S1 of FIG. 5, the throttle valve 1
Whether or not 08 is fully closed, in other words, whether or not the throttle valve opening degree θ _th is zero is determined based on the signal from the throttle sensor 110. If the determination in step S1 is negative, the routine is terminated because the coasting state is not established. However, if the determination in step S1 is affirmative, whether or not the fuel cut control is being executed in step S2 is determined from the engine control electronic control device 160 to the shift control electronic control device 16.
Judgment is made based on the signal F _cut to 2.

If the determination in step S2 is negative, the routine is terminated because the vehicle is in a traveling state in which no discomfort due to the fuel cut control will occur.
However, when the determination in step S2 is affirmative, it is determined in step S3 whether the gear ratio γ of the CVT 14 is larger than a preset determination reference value γ _O. The determination reference value γ _O is an experimental value for determining whether or not the vehicle is in a running state that does not require the engine brake mitigation control, and is, for example, the third gear ratio in the fourth gear A / T and the third gear ratio. An intermediate value of the gear ratio of the fourth speed is set.
If the determination in step S3 is negative, this routine is ended.

However, if the determination in step S3 is affirmative, then in step S4, the target engine braking force F (V) which is the desired optimum value for eliminating the discomfort during coasting with fuel cut control. ) ° is calculated based on the actual vehicle speed V from the pre-stored relationship shown in FIG. 6, and the gear ratio γ ₁ for calculating the reverse drive torque is calculated from the following equation (1), and the target engine The target reverse drive torque -T _e ° of the engine 10 for obtaining the braking force F (V) ° is calculated from the following equation (2) based on the target engine braking force F (V) ° and the gear ratio γ _1. . In the following equations (1) and (2), C and A are constants.

[0026]

[Equation 1] γ ₁ = N _in ° C / V ・ ・ ・ (1)

[0027]

[Equation 2] −T _e ° = F (V) ° / (γ ₁ · A) (2)

In the following step S5, in order to generate the target reverse drive torque -T _e ° calculated in step S4, for example, the actual engine rotational speed N _e and the target reverse drive torque are calculated from the prestored relationship shown in FIG. Torque-T
The duty ratio α ° of the solenoid valve 142 is determined based on _e °, and a signal R _res representing the duty ratio α ° is output from the shift control electronic control unit 162 to the engine control electronic control unit 160. . Therefore, the engine control electronic control unit 160 drives the electromagnetic on-off valve 142 at the duty ratio α ° to cause the engine 10 to generate the target reverse drive torque −T _e °. As shown by the line, the feeling of coasting similar to that of a vehicle equipped with a conventional A / T can be obtained.

As described above, according to this embodiment, the fuel cut control of the engine control electronic control unit 160 (that is, the fuel cut control unit) is in operation in step S2 corresponding to the fuel cut determination means. In the determined state, the target reverse drive torque -T _e ° calculated based on the vehicle speed V and the gear ratio γ ₁ of the CVT 14 during the fuel cut control is obtained in step S4 corresponding to the target reverse drive torque calculation means. Further, the electromagnetic on-off valve 142 is operated via the engine control electronic control unit 160 by the shift control electronic control unit 162 functioning as the rotation resistance control means.

Therefore, during the fuel cut control, even if the gear ratio γ is changed toward its maximum value γ _max prior to the stop of the vehicle in order to obtain the driving force when the vehicle restarts, the change is obtained. In the process, since the electromagnetic on-off valve 142 is operated so as to obtain the target reverse drive torque -T _e °, the engine braking force is set to the desired optimum value and is relaxed as compared with the conventional one, so that the driver is informed. The discomfort is preferably eliminated.

Further, according to this embodiment, the solenoid opening / closing valve 14
The gas escaped from the combustion chamber 138 through No. 2 is returned to the intake pipe 104 again via the recirculation pipe line 158.
It has the advantage of not releasing hydrocarbons into the atmosphere.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention can be applied to other modes.

For example, in the above-described embodiment, the CVT 14 is used as a transmission that automatically changes the gear ratio γ. However, a plurality of sets of planetary gear units and their elements may be mutually or non-rotating members. It may be an automatic transmission of a type in which a desired gear stage among a plurality of gear stages is established by being selectively engaged and the gear ratio is automatically switched.

In step S4 of the above-mentioned embodiment,
In the formula (1), the target input shaft rotation speed N _in ° and the vehicle speed V
The gear ratio γ ₁ for reverse drive torque calculation is calculated from (2)
In the formula, the gear ratio γ ₁ is used to calculate the target reverse drive torque −T _e °, but it follows the target input shaft rotation speed N _in ° even during coasting running in which the fuel cut control is executed. If the control is suitable,
The actual gear ratio γ of the CVT 14 may be used because the gear ratio γ ₁ for calculating the reverse drive torque is approximately the same value. Further, the actual input shaft rotation speed N _in may be used instead of the target input shaft rotation speed N _in ° _{in the} equation (1).

In step S4 of the above-mentioned embodiment,
The target engine braking force F (V) ° was determined based on the actual vehicle speed V from the relationship indicating the desired engine braking force in FIG. 6, but the relationship is not limited to that shown in FIG. It may be set to a straight line, and the target engine braking force F (V) ° may be a constant value, for example. Even in this case, the reverse drive torque of the engine as shown by the line C in FIG. 4, for example, can be obtained, and the discomfort can be reduced as compared with the conventional case. In this case, the target reverse drive torque -T _e ° is calculated from the equation (2) based on the gear ratio γ ₁ for calculating the reverse drive torque or the actual gear ratio γ of the CVT 14.

Further, in the above-described embodiment, in order to change the reverse driving torque of the engine 10, that is, the rotation resistance, the operation shown in FIG.
Although the rotation resistance adjusting device 118 shown in FIG. 2 is used, a valve timing switching means described in, for example, Japanese Patent Laid-Open No. 63-147957 may be used instead. In this case, the intake valve 128 is closed early or the intake valve 128 and the exhaust valve 132 are overlapped with each other to reduce the pumping loss.

Further, in the above-described embodiment, the engine braking torque of the engine 10 is changed by the electromagnetic opening / closing valve 142 during the fuel cut control in coasting, but the CV is changed during traveling downhill at a low vehicle speed.
The vehicle speed V may be controlled to be constant by changing the engine brake torque of the engine 10 by the electromagnetic opening / closing valve 142 without changing the gear ratio γ of T14 so much. With this configuration, the rotation speed of the engine 10 can be reduced and noise can be suppressed as compared with the control that keeps the vehicle speed V constant by changing the gear ratio γ of the CVT 14 while traveling on a downhill. is there.

The above description is merely one embodiment of the present invention, and the present invention can be variously modified without departing from the gist thereof.

[Brief description of drawings]

FIG. 1 is a schematic diagram of the present invention.

FIG. 2 is a block diagram illustrating a configuration of an exemplary embodiment of the present invention.

FIG. 3 is an enlarged view for explaining the configuration of the main part of the embodiment of FIG.

FIG. 4 is a diagram illustrating a shift control operation and a change in reverse drive torque in the embodiment of FIG.

FIG. 5 is a flowchart illustrating an operation of engine brake mitigation control according to the embodiment of FIG.

6 is a diagram showing a pre-stored relationship used when determining a target engine braking force F (V) ° in the flowchart of FIG.

FIG. 7 is a duty ratio α in the flowchart of FIG.
It is a figure which shows the pre-stored relationship used when determining (degree).

[Explanation of symbols]

142: electromagnetic on-off valve (rotational resistance adjusting means) 160: electronic control device for engine control (fuel cut control device) 162: electronic control device for gear change control (gear ratio control device, rotation resistance control means) Step S2: fuel cut determination Means Step S4: Target Reverse Driving Torque Calculating Means

Claims (1)

[Claims] 1. An automatic transmission capable of speed-changing engine rotation and transmitting it to drive wheels and automatically changing a gear ratio, a throttle valve opening being substantially zero, and an engine rotation speed being predetermined. A fuel cut control device that shuts off fuel supplied to the engine when the fuel cut rotation speed is higher than the fuel cut rotation speed, and a gear ratio of the automatic transmission according to a decrease in vehicle speed when the throttle valve opening is substantially zero. Is a deceleration side gear ratio control device for a vehicle, the fuel cut control device for determining whether or not the fuel cut control device is in operation; Target reverse drive torque calculating means for calculating a target reverse drive torque based on at least the gear ratio of the automatic transmission so that the engine braking force to be achieved becomes a desired value, The rotational resistance adjusting means for adjusting the rotational resistance of the engine in the state where the fuel to the engine is cut off, and the rotational resistance adjustment so as to match the target reverse drive torque during the operation of the fuel cut control device. A control device for a vehicle having an automatic transmission, comprising: a rotation resistance control means for operating the means.