JPH0893906A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE: To reduce the occurrence shift shock and shorten the gear change time y positively lowering engine rotational frequency at up shifting gear change in accordance with reduction of throttle opening. CONSTITUTION: Whether a 1→ flag shifting up from one-speed to two speed in back out state is determined (step S2). If the 1→flag is provided, a delay timer DRYT is set to an initial value KDR12BO (step S3) and also line pressure PL discharged by an oil pump 56 is set at maximum pressure (step S4). The delay timer DRYT 18 subtracted by one (step S6, S7) and a solenoid pattern is set to two-speed at the time the initial value KDR12BO passes (step S8) and also the line pressure PL is set to 1→2 change gear value (step S9).

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 an automatic transmission having a shift mode in which automatic shift is performed with a throttle opening of an engine as one of control parameters, and shift up is performed by a decrease in throttle opening.

[0002]

2. Description of the Related Art As is generally known, an automatic transmission mounted on a vehicle uses a throttle opening and a vehicle speed as main parameters of a shift control, and a shift line as a switching boundary of each shift speed is a throttle opening. It has a characteristic that it changes proportionally with a certain inclination as the degree and vehicle speed increase.
For this reason, when the accelerator pedal is returned in the coasting state where the engine brake does not act, only the throttle opening is reduced while the vehicle speed is kept substantially constant. Therefore, the shift point crosses the shift line on the upshift side, resulting in an upshift.

By the way, in the case of shifting up by returning the accelerator in this way, a large shock is generated because the gear ratio sharply decreases in a state where the engine speed is high. Therefore, conventionally, the point at which the upshift is substantially performed is delayed to wait for a decrease in the engine speed due to the accelerator release, and the upshift is performed in a state in which the engine speed has decreased to some extent. For example, Japanese Patent Laid-Open No. 3-2
Japanese Patent Publication No. 29061 (F16H 61/08) discloses that the delay time for upshifting is changed depending on the traveling condition.

[0004]

However, in such a conventional control device for an automatic transmission, even when the upshift delay time is made to depend on the running condition, it is passively waited for a decrease in the engine speed. As a result, the delay time inevitably becomes long, resulting in a long shift time. Therefore, there is a problem that it is difficult to further improve the shift feeling.

In view of the conventional problems, the present invention reduces the occurrence of gear shift shock by positively reducing the engine speed during a gear shift that is upshifted as the throttle opening decreases. An object of the present invention is to provide a control device for an automatic transmission, which can shorten the shift time.

[0006]

In order to achieve the above object, the present invention is directed to a control device for an automatic transmission having a shift mode in which the engine shifts up as the throttle opening is decreased. Speed-up command due to a decrease in the degree of shift, a shift-delay means for executing a substantial upshift shift after maintaining the current shift-stage for a predetermined time, and a shift-stage before the shift-up by the operation of the shift-delay means. Is maintained, the engine rotation speed lowering means for forcibly lowering the rotation speed of the engine is provided.

Further, the engine speed reduction means can be constructed as a line pressure correction means for increasing the line pressure controlled by the line pressure control means.

Further, the engine speed reduction means can be configured as a means for increasing the load of an auxiliary machine driven by the engine.

Furthermore, it is desirable that the accessory be a variable displacement type oil pump for generating a line pressure for engaging a friction element of an automatic transmission.

[0010]

In the automatic transmission control device of the present invention having the above-described structure, the shift delay means causes the shift-up command to shift up for a predetermined period of time from the actual shift-up command.
The current shift speed is maintained, and while the current shift speed is maintained, the engine speed is forcibly reduced by the rotation speed reduction means, so The period during which the engine speed drops corresponding to the change is significantly shortened.

Further, the engine speed reduction means is constituted as a line pressure correction means for increasing the line pressure controlled by the line pressure control means, whereby the engine load is increased by increasing the line pressure and the engine rotation speed is increased. The number has been reduced, and it is possible to deal with this by simply changing the line pressure control software.

Further, the engine speed reducing means is a means for increasing the load of the auxiliary equipment driven by the engine, so that the engine speed can be effectively reduced by using the existing apparatus.

Furthermore, the auxiliary machine is a variable displacement type oil pump for generating a line pressure for engaging the friction element of the automatic transmission, so that the capacity of the oil pump is increased to provide a proper engine. The load can be applied, and the forced reduction of the engine speed can be smoothly performed.

[0014]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 1 to 5 show an embodiment of a control device for an automatic transmission according to the present invention, FIG. 1 is a schematic configuration diagram of a gear train of the automatic transmission, and FIG. 2 is a diagram showing friction elements in each gear of the automatic transmission. FIG. 3 is an explanatory diagram showing an operating state, FIG. 3 is a schematic configuration diagram of a control device for an automatic transmission, FIG. 4 is a flowchart for performing shift control of this embodiment, and FIG. 5 is a time of each element obtained by the shift control of this embodiment. It is a chart.

That is, as shown in FIG. 1, the automatic transmission 10 of this embodiment is provided with two planetary gear mechanisms, a first planetary gear 12 and a second planetary gear 14, and these first and second planetary gear mechanisms are provided. In each power transmission path of the planetary gears 12, 14, a forward clutch 16, a 3-4 clutch 18,
Reverse clutch 20, low and reverse brake 2
A friction element such as a 2, 2-4 brake 24 and a one-way clutch 26 are arranged. Further, engagement and disengagement of each of the friction elements is controlled by an operating oil pressure supplied from an oil pump (not shown), so that a shift speed corresponding to each operating condition such as vehicle speed and accelerator opening degree can be obtained. The forward clutch 16 and the 3-4 clutch 1
8, the reverse clutch 20 and the low and reverse brake 22 are each configured as a multi-plate clutch, and the 2-4 brake 24 is configured as a band brake.

An engine (not shown) is arranged on the right side of the automatic transmission 10 in the drawing, and the engine rotation is input to the input shaft 30 of the automatic transmission 10 via the torque converter 28. Is appropriately shifted by the gear train, and then output to the differential gear 36 via the output drive gear 32 and the output driven gear 34.

Further, the automatic transmission 10 of this embodiment provided with the gear train having the above-mentioned structure is provided with a forward clutch 16
(Fwd CL), 3-4 clutch 18 (3-4 CL), reverse clutch 20 (Rev CL), low and reverse brake 22 (L / R Br), 2-4 brake 24 (2-4 Br) By engaging and releasing as shown in 2, 1
st (forward 1st speed), 2nd (forward 2nd speed), 3rd (forward 3)
Each of the speed stages, 4th (4th forward speed) and Rev (reverse speed) can be obtained. In the table, ◯ indicates a fastened state and x indicates a released state. The table also shows the operating state of the one-way clutch (OWC), where L indicates the locked state and F indicates the free state.

The forward clutch 16 (Fwd CL),
3-4 clutch 18 (3-4 CL), reverse clutch 20
(Rev CL) and low and reverse brake 22 (L /
R Br) and 2-4 brake 24 (2-4 Br) are connected and released by the control valve 38 shown in FIG. That is,
FIG. 3 schematically shows a control device 40 of the automatic transmission 10,
A shift signal is input to the control valve 38 from a controller 42 formed of a microcomputer. The controller 42 is provided with a shift means 44 for controlling the shift signal, and mainly uses the throttle opening signal and the vehicle speed signal input from the throttle opening sensor 46 and the vehicle speed sensor 48 and other operating conditions such as oil. The shift signal is processed according to a shift map that is input in advance while taking into consideration the temperature and the like.

A line pressure control signal is input from the controller 42 to the control valve 38, and a line pressure control means 51 provided in the controller 42 outputs a throttle opening signal indicating an engine load. The corresponding line pressure is controlled. The control valve 38 is specifically a duo that controls the control pressure of the pressure regulating valve that controls the line pressure.
A tea solenoid or the like is provided and controlled by a control signal from the controller 42.

Here, in this embodiment, the controller 4
2, a shift delay means 50 and a line pressure correction means 52 as an engine speed reduction means are provided. The gear shift delay means 50 substantially holds the current gear stage for a predetermined period of time when a so-called loose back-out shift-up is performed in which the accelerator pedal is released to shift up in a coasting state where the engine brake does not act. It is designed to execute an upshift. Further, the line pressure correcting means 52 increases the driving load of the engine 54 by increasing the line pressure while the current shift speed is maintained by the shift delaying means 50, and the engine 54
It is designed to forcibly reduce the rotation speed of.

The engine 5 serves as a hydraulic pressure source for the line pressure.
An oil pump 56 that is driven four times is used. The hydraulic oil discharged from the oil pump 56 is supplied as a line pressure via a pressure regulating valve provided in the control valve 38, and the line pressure is supplied to the friction elements so that these friction elements are It is designed to be concluded and released.

FIG. 4 is a flow chart for the controller 42 to execute the control at the time of the back-out shift. First, various signals such as the engine speed Ne and the throttle opening are read in step S1, and the back speed is set in the next step S2. Shifting up from 1st gear to 2nd gear in the out state 1
→ 2 It is determined whether or not the flag is output (0 → 1).
In the present embodiment, the shift control will be described by taking upshifting from the first speed to the second speed as an example.

If it is determined in step S2 that the 1 → 2 flag is output (YES), the delay timer DRYT is set to the initial value KDR12BO in step S3, and the line pressure PL is set to the maximum (MAX) in step S4. ) Set to pressure. The initial value KDR12BO is set to a time during which the engine speed is reduced to near idle speed.

On the other hand, if NO is determined in the step S2, if the 1 → 2 flag is not output, or if the 1 → 2 flag is already set.
→ If the 2 flag has been output, the next step S
5, it is determined whether the 1 → 2 flag is in the 1 state, that is, whether the 1 → 2 flag is continuously output. Then, when the 1 → 2 flag continues to appear (Y
ES) subtracts the delay timer DRYT by 1 in steps S6 and S7, and when the initial value KDR12BO set in step S3 has passed, step S8
Sets the solenoid (SOL) pattern to 2nd speed. By setting the solenoid pattern to the 2nd speed in this manner, the 2-4 brake 24 as shown in FIG.
(2-4 Br) is engaged to switch to the 2nd speed. Also,
In step S9, the line pressure PL, which has been set to the MAX pressure in step S4, is set to the 1 → 2 shift pressure. If it is determined in step S5 that the 1 → 2 flag is not output (NO), the line pressure PL is set to the normal pressure in step S10.

In the automatic transmission control apparatus of the present embodiment having the above-described structure, when the 1 → 2 flag as the shift-up shift command is issued in the backout state as shown in the time chart of FIG. , The delay timer is activated to delay the second speed of the solenoid pattern to maintain the first speed, and while the delay timer is operating,
The line pressure PL is the maximum pressure. In the figure, the solid line shows the characteristics of this embodiment, and the broken line shows the conventional characteristics. By thus maximizing the line pressure PL, the driving force of the oil pump 56 increases, and the load of the engine 54 increases correspondingly. Therefore, the rate of decrease of the engine speed reduced by the accelerator return is significantly larger than that of the conventional engine.

When the engine speed is reduced to near the idle speed, the delay timer is ended, the solenoid pattern is set to the second speed, and the second speed is applied. The line pressure PL is lowered to the set pressure of the second speed at the time of being applied to the second speed, and the load of the oil pump 56 acting on the engine 54 is reduced.

As described above, in this embodiment, when shifting up in the back-out state, the line pressure PL can be maximized to increase the rate of decrease of the engine speed. It is possible to significantly reduce the time until it is done. Further, since the engine rotation speed is rapidly reduced, the engine rotation speed at the time of being put into the second gear can be further lowered. Therefore, the fluctuation portion P of the shaft torque when substantially upshifted is reduced to the conventional value. Fluctuation part Q
It is possible to make it much smaller than the above, and it is possible to significantly reduce the thrust shock at the time of shifting.

In this embodiment, the means for lowering the engine speed by increasing the line pressure PL is disclosed, but other than this, the means for increasing the load of the auxiliary equipment driven by the engine is used to rotate the engine during upshifting. Can be reduced. For example, the oil pump 56 is configured as a variable displacement type in which the discharge amount is variable by driving a solenoid, but the engine load can be increased by increasing the discharge amount of the oil pump 56. Further, in the present embodiment, the upshift by the 1 → 2 shift is shown as an example, but it goes without saying that the present invention can be applied to other upshifts.

[0029]

As described above, in the control device for an automatic transmission according to claim 1 of the present invention, the predetermined time from the shift up command to the substantial upshift is currently controlled by the shift delay means. The gear speed is maintained and the engine speed is forcibly reduced by the engine speed lowering means, so that the engine inertia speed corresponding to the shift to the up-shift gear speed is promoted to absorb the absorption inertia. As a result, the shock of thrusting up the shaft torque is reduced to enable a smoother gear shift, and a faster shift up is made possible by promoting a decrease in the engine speed to improve the feeling during gear shift.

Further, according to a second aspect of the present invention, since the engine speed reduction means is constituted as a line pressure correction means for increasing the line pressure controlled by the line pressure control means, the engine is increased by increasing the line pressure. It is possible to reduce the engine speed by increasing the drive load of the above, and it is possible to deal with it only by changing the line pressure control software, and the configuration can be remarkably simplified.

Further, according to the third aspect of the present invention, the engine speed reduction means is means for increasing the load of the auxiliary machine driven by the engine. The number can be reduced, and the control device can be configured without increasing the cost.

Further, in claim 4 of the present invention, the auxiliary machine is a variable displacement type oil pump for generating a line pressure for engaging the friction element of the automatic transmission.
By increasing the capacity of the oil pump, an appropriate engine load can be applied, and various excellent effects can be achieved such that the engine speed can be forcibly reduced smoothly.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a gear train showing an embodiment of an automatic transmission to which a control device of the present invention is applied.

FIG. 2 is an explanatory diagram showing an operating state of a friction element at each shift speed of the automatic transmission according to the embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a control device for an automatic transmission showing an embodiment of the present invention.

FIG. 4 is a flowchart for performing shift control in an embodiment of the control device of the present invention.

FIG. 5 is a time chart of each element obtained by the shift control of the embodiment of the control device of the present invention.

[Explanation of symbols]

10 Automatic Transmission 40 Control Device 42 Controller 44 Gear Shifting Means 46 Throttle Opening Sensor 48 Vehicle Speed Sensor 50 Gear Shift Delaying Means 51 Line Pressure Control Means 52 Line Pressure Correcting Means (Engine Revolution Decreasing Means) 54 Engine 56 Oil Pump

Claims (4)

[Claims] 1. A control device for an automatic transmission having a shift mode that shifts up with a decrease in the throttle opening of an engine, in a predetermined time after receiving a shift up command due to a decrease in the throttle opening. A shift delay means for executing a substantial upshift after the current shift speed is maintained, and the engine speed is forcibly reduced while the shift speed before the upshift is maintained by the operation of the shift delay means. A control device for an automatic transmission, comprising: an engine rotation speed lowering means for controlling the engine speed. 2. The control means for an automatic transmission according to claim 1, wherein the engine speed reduction means is a line pressure correction means for increasing the line pressure controlled by the line pressure control means. 3. The control device for an automatic transmission according to claim 1, wherein the engine speed reduction means is means for increasing a load of an auxiliary machine driven by the engine. 4. The control device for an automatic transmission according to claim 3, wherein the auxiliary device is a variable displacement type oil pump for generating a line pressure for engaging a friction element of the automatic transmission. .