JPH07293684A - Lockup controller of torque converter - Google Patents

Abstract

PURPOSE:To change advance speed into suitable speed by running conditions such as gear position of a transmission, etc., when a torque converter is locked up. CONSTITUTION:A computer 31 makes a lockup clutch 22 of a torque converter 13 between an engine 10 and a gear shift mechanism 42 tightened via a control valve 25 by a solenoid valve 29. At this time, the computer 31 calculates the number of revolutions of a turbine from a gear shift ratio obtained from a gear position G and the number of revolutions output by the mechanism 42 to obtain slip amount DELTAN based on a difference between the number of revolutions of an engine Ne and the number of revolutions of the turbine. The computer 31 makes the clutch 22 tightened at a speed which corresponds to a value obtained by multiplying DELTAN by feedback constant K, and changes the constant K in accordance with the gear position G in such a manner that the clutch 22 is tightened at higher speed, if it is at a higher speed gear position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lock for completing a torque converter inserted in a transmission system of an automatic transmission at an appropriate speed when the torque converter is brought into a lockup state in which input and output elements are directly connected. The present invention relates to an up control device.

[0002]

2. Description of the Related Art In order to improve fuel efficiency by improving transmission efficiency, an automatic transmission is equipped with a torque converter which is capable of operating under a vehicle operating condition in a lockup region where a torque increasing function and a torque fluctuation absorbing function are not required. In many cases, the input / output elements are of a type that can be brought into a lockup state in which they are directly connected to each other by engaging a lockup clutch.

In the lock-up control of this kind of torque converter, a specific shift is conventionally used, for example, as described in the automatic transmission described in "NISSAN RE4R01A type full range electronic control automatic transmission maintenance manual" issued by the applicant of the present application. For each gear or each gear, it is determined which of the vehicle operating state is the lockup region and the converter region defined by the throttle opening (engine load) and the vehicle speed, and the torque converter is determined according to the determination result. In the lockup region, it is a common practice to engage the lockup clutch to establish a lockup state in which the input / output elements are directly connected, and in the converter region to open the lockup clutch to establish a converter state in which the direct connection is released.

Generally, as described in the above-mentioned document, the lock-up clutch is engagement control based on a control command amount obtained by multiplying a torque converter slip amount, which is a relative rotation between torque converter input / output elements, by a feedback constant. Therefore, the engagement speed of the lockup clutch is determined by the feedback constant.

[0005]

By the way, conventionally, since the above feedback constant is a constant value, the engagement speed of the lock-up clutch is only one kind, which causes the following problems. That is, in order to enhance the fuel consumption improving effect due to the lockup of the torque converter, it is preferable to engage the lockup clutch as fast as possible. However, when the engagement speed of the lockup clutch is too fast, engagement shock of the clutch, that is, lockup shock occurs.

The most suitable engagement speed within the range in which the engagement shock of the lock-up clutch does not occur varies depending on the selected gear position of the transmission, the hydraulic oil temperature, the load state of the engine, and the vehicle speed. The reason is that when the selected gear position of the transmission is different, the rotational inertia of the power train including the transmission and the engine, which is related to the magnitude of the lockup shock that is related to the engagement speed of the lockup clutch, is different and the operation is different. Even if the oil temperature is different, the friction loss of the transmission, which is related to the magnitude of the lockup shock that is related to the engagement speed of the lockup clutch, is different, and the load state of the engine is also different, the lockup clutch Related to the magnitude of the lockup shock that occurs depending on the engagement speed, even when the engine output torque is different and the vehicle speed is also different, it is related to the magnitude of the lockup shock that occurs related to the engagement speed of the lockup clutch , Because the rotational inertia energy of the above power train is different A.

However, when the feedback constant is a constant value and there is only one type of engagement speed of the lockup clutch as in the conventional lockup control device, various suitable engagement speeds of the lockup clutch as described above are provided. It was not possible to achieve both of these by satisfying the above conditions at all times and satisfying both the fuel efficiency improvement effect due to the lockup and the elimination of the lockup shock at the same time.

The present invention is based on the fact that the selected gear position of the transmission has the greatest influence on the above-mentioned problem, and at least changes the engaging speed of the lockup clutch in accordance with the selected gear position to solve the above problem. The purpose is to eliminate.

To this end, the lockup control device for a torque converter according to the first aspect of the present invention is driven by an input element 2 driven by a power source 1 and a working fluid stirred by the input element 2 as shown in the concept of FIG. An output element 4 for transmitting power to the transmission 3 and a lockup clutch 5 capable of directly connecting these input / output elements are provided. The lockup clutch is used as a product of a torque converter slip amount and a feedback constant. In the lockup control device of the torque converter 6 provided with the lockup control means 7 for engaging at a speed corresponding to the gear position detection means 8 for detecting the selected gear position of the transmission 3 and the gear position detected by this means. Accordingly, a feedback constant changing means 9 for changing the feedback constant is provided. It is.

In the second aspect of the present invention, the feedback constant changing means changes the feedback constant so that the engagement speed of the lockup clutch becomes faster as the gear position becomes higher.

In the third invention, in addition to the first invention or the second invention, working fluid temperature detecting means for detecting the temperature of the working fluid is provided. Then, the feedback constant changing means is configured to change the feedback constant also according to the working fluid temperature detected by the means.

In a fourth aspect of the invention, the feedback constant changing means in the third aspect of the invention is configured to change the feedback constant such that the engagement speed of the lockup clutch becomes faster as the working fluid temperature becomes higher.

In a fifth invention, the first invention or the second invention
In addition to the invention, power source load detection means for detecting the load state of the power source is provided. Then, the feedback constant changing means is configured to change the feedback constant also according to the power source load detected by the means.

In the sixth aspect of the invention, the feedback constant changing means in the fifth aspect of the invention is configured to change the feedback constant such that the higher the power source load, the faster the engagement speed of the lockup clutch.

In the seventh invention, the fifth invention or the sixth invention
In addition to the invention, vehicle speed detecting means for detecting the vehicle speed is provided. Then, the feedback constant changing means is configured to change the feedback constant also according to the vehicle speed detected by the means.

In the eighth invention, the feedback constant changing means in the seventh invention is configured to change the feedback constant so that the engagement speed of the lockup clutch becomes faster as the vehicle speed becomes higher.

In the ninth invention, the third invention or the fourth invention
In addition to the invention, a power source load detecting means for detecting a load state of the power source and a vehicle speed detecting means for detecting a vehicle speed are provided. Then, the feedback constant changing means is configured to change the feedback constant according to the power source load and the vehicle speed detected by the means.

In a tenth aspect of the invention, the feedback constant changing means in the ninth aspect of the invention is configured to change the feedback constant such that the engagement speed of the lockup clutch becomes faster as the power source load becomes higher.

In the eleventh invention, the feedback constant changing means in the ninth invention or the tenth invention is
The feedback constant is changed so that the engagement speed of the lockup clutch becomes faster as the vehicle speed becomes higher.

[0020]

In the first aspect of the present invention, the torque converter 6 is in a converter state in which the input / output elements 2 and 3 are not directly connected by the engagement of the lockup clutch 5 at a speed according to the product of the torque converter slip amount and the feedback constant. From the lockup state in which the input / output elements 2 and 3 are directly connected.

Here, the feedback constant changing means 9 is
The above feedback constant is changed according to the selected gear position of the transmission 3 detected by the gear position detecting means 8. Therefore, the engagement speed of the lock-up clutch determined by the feedback constant is changed according to the selected gear position of the transmission 3, and a different suitable engagement speed of the lock-up clutch can be achieved for each selected gear position. It is possible to perform control such that the lockup clutch is fastened within the range where the lockup shock is not generated, and it is possible to reduce the lockup shock and improve the fuel economy by the lockup.

In the second aspect of the invention, the feedback constant changing means changes the feedback constant such that the engagement speed of the lockup clutch becomes faster as the gear position becomes higher. Therefore, the higher the selected gear position of the transmission is, the lower the rotational speed of the power source is. As a result, the rotational inertia of the power train including the power source and the transmission is reduced, and the lockup shock is reduced. In response to this, the engagement speed of the lock-up clutch is increased, and it is possible to prevent the engagement speed of the lock-up clutch from being unnecessarily slowed and prevent the fuel consumption improving effect due to the lock-up from decreasing.

In the third invention, the working fluid temperature detecting means provided in addition to the first invention or the second invention detects the temperature of the working fluid, and the feedback constant changing means detects it. The feedback constant is also changed according to the working fluid temperature. Therefore, the engagement speed of the lockup clutch, which is determined by the feedback constant, is changed depending on the temperature of the working fluid, and it is possible to achieve a suitable engagement speed of the lockup clutch that varies depending on the temperature of the working fluid. In addition, the control such as engaging the lockup clutch most quickly within the range where lockup shock is not generated is possible more than the first invention or the second invention, and the effect of reducing the lockup shock and improving the fuel efficiency by the lockup is achieved. It is possible to achieve both and more reliably.

In the fourth invention, the feedback constant changing means in the third invention changes the feedback constant so that the engagement speed of the lockup clutch becomes faster as the working fluid temperature becomes higher. Therefore, as the temperature of the working fluid increases, the friction loss of the transmission decreases due to the decrease in viscosity, and as a result, the rotation inertia of the transmission decreases and the lockup shock decreases, which in turn reduces the engagement speed of the lockup clutch. Since the speed is increased, it is possible to prevent the engagement speed of the lockup clutch from being unnecessarily slowed and prevent the fuel consumption improving effect due to the lockup from decreasing.

In the fifth invention, the first invention or the second invention
The power source load detecting means provided in addition to the invention detects the load state of the power source, and the feedback constant changing means changes the feedback constant also according to the power source load detected by the means. Therefore, the engagement speed of the lockup clutch determined by the feedback constant is changed depending on the power source load state, and it is possible to achieve a suitable lockup clutch engagement speed for each power source load state. In addition, the control such as engaging the lockup clutch most quickly within the range where lockup shock is not generated is possible more than the first invention or the second invention, and the effect of reducing the lockup shock and improving the fuel efficiency by the lockup is achieved. It is possible to achieve both and more reliably.

In the sixth invention, the feedback constant changing means in the fifth invention changes the feedback constant such that the engagement speed of the lockup clutch becomes faster as the power source load becomes higher. Therefore, as the power source load increases, the output torque of the power source increases and it becomes difficult to engage the lock-up clutch, so the engagement speed of the lock-up clutch is increased, and the lock-up clutch is unnecessarily locked up. It is possible to prevent the fuel consumption improvement effect due to lockup from being lowered by slowing the clutch engagement speed.

In the seventh invention, the fifth invention or the sixth invention
The vehicle speed detecting means provided in addition to the invention detects the vehicle speed, and the feedback constant changing means changes the feedback constant according to the vehicle speed detected by the means. Therefore, the engagement speed of the lockup clutch that is determined by the feedback constant is also changed according to the vehicle speed, and it is possible to achieve a suitable engagement speed of the lockup clutch that differs for each vehicle speed, resulting in a lockup shock. In the range that does not exist, the control such as engaging the lockup clutch most quickly is possible even more than the fifth invention or the sixth invention, and it is possible to more reliably reduce the lockup shock and improve the fuel efficiency by the lockup. Can be made.

In the eighth invention, the feedback constant changing means in the seventh invention changes the feedback constant such that the engagement speed of the lockup clutch becomes faster as the vehicle speed becomes higher. Therefore, the higher the vehicle speed, the higher the rotational speed of the power train including the power source and the transmission, and the greater the rotational inertia energy of the power train.
Since the engagement speed of the lockup clutch is increased, it is possible to prevent the engagement speed of the lockup clutch from being unnecessarily decreased to prevent the fuel consumption improving effect due to the lockup from decreasing.

In the ninth invention, the third invention or the fourth invention is provided.
The power source load detection means and the vehicle speed detection means provided in addition to the invention respectively detect the load state of the power source and the vehicle speed. Then, the feedback constant changing means also changes the feedback constant according to the power source load and the vehicle speed detected by these means. Therefore, the engagement speed of the lockup clutch, which is determined by the feedback constant, is changed depending on the power source load condition and the vehicle speed. It is possible to achieve the control such as engaging the lock-up clutch at the fastest speed within the range where lock-up shock is not generated, more easily than the third invention or the fourth invention. The effect of improving fuel efficiency can be more reliably achieved at the same time.

In the tenth aspect of the invention, the feedback constant changing means in the ninth aspect of the invention changes the feedback constant such that the higher the power source load, the faster the engagement speed of the lockup clutch. Therefore, as the power source load increases, the output torque of the power source increases and it becomes difficult to engage the lock-up clutch, so the engagement speed of the lock-up clutch is increased, and the lock-up clutch is unnecessarily locked up. It is possible to prevent the fuel consumption improvement effect due to lockup from being lowered by slowing the clutch engagement speed.

In the eleventh invention, the feedback constant changing means in the ninth invention or the tenth invention is:
The feedback constant is changed so that the engagement speed of the lockup clutch becomes faster as the vehicle speed becomes higher. Therefore, the higher the vehicle speed, the higher the rotational speed of the power train including the power source and the transmission, and the greater the rotational inertia energy of the power train. Since the speed is increased, it is possible to prevent the engagement speed of the lockup clutch from being unnecessarily slowed and prevent the fuel consumption improving effect due to the lockup from decreasing.

[0032]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 shows an embodiment of the lock-up control device of the present invention together with a torque converter in an automatic transmission for a vehicle to be controlled by the lock-up control device. Reference numeral 10 in the drawing is an engine as a power source, 11 is its crankshaft, and 12 is a fly. A wheel, 13 is a torque converter, and 14 is a torque converter output shaft. During operation of the engine 10, the crankshaft 11 is rotating together with the flywheel 12, and the torque converter 13 is drive-coupled to the crankshaft 11 via the flywheel 12 and a pump impeller (input element) 13a that is always driven by the engine, The turbine runner 13 includes a turbine runner (output element) 13b and a stator (reaction force element) 13c that face each other.
b is drivingly connected to the output shaft 14, and the stator 13c is placed on the hollow fixed shaft 16 via the one-way clutch 15.

In the torque converter 13, the working fluid from the pump 17 is supplied to the internal converter chamber 13d through the supply passage 18, the working fluid is returned to the reservoir 20 through the return passage 19, and the radiator provided in the middle thereof. Cool with 21. A pressure-retaining valve (not shown) is inserted in the return path 19 to keep the pressure in the converter chamber 13d at a pressure (converter pressure) P _C below a certain value. Thus, the pump impeller 13a driven by the engine as described above stirs the internal working fluid, collides it with the turbine runner 13b, and then causes it to flow to the stator 13c, while the torque of the turbine runner 13b is increased under the reaction force of the stator 13c. Rotate while letting. The operating torque converter 13 in such a converter state can transmit the power of the engine 10 to the output shaft 14 under vibration control and torque increase while causing slip (relative rotation) between the input / output elements 13a and 13b. The power from the output shaft 14 is shifted by a gear transmission 42 of the automatic transmission (in this example, the first speed to the fourth speed can be selected) 42 to rotate the drive wheels of the vehicle,
The vehicle can be driven.

The torque converter 13 is further provided with the above slip.
Lock up to make it a lock-up type that can be stopped
It has a clutch 22 and a torsion damper 23.
It is drivingly connected to the output shaft 14 via the
The lock-up chamber 24 is set to be movable in the direction. Kura
The switch 22 has a lockup pressure P in the lockup chamber 24.
_{L / U}Converter in the converter chamber 13d
Pressure P_CThe left-hand side in the figure is fastened and fastened, and the input / output element 13
Torque convertor by driving connection between a and 13b
The key 13 can be locked up.

The lock-up pressure P _{L / U} is adjusted by the lock-up control valve 25 as will be described later. For this purpose, the lock-up chamber 24 passes through the hollow hole of the shaft 14 and the circuit 26, and the lock-up control valve 25 of the lock-up control valve 25. Connect to port 25a. The valve 25 is additionally provided with a port 25b for guiding the converter pressure P _C by a circuit 27 and a drain port 25c, and when the spool 25d is in the neutral position shown in the drawing, the port 25b is provided.
a from both ports 25b and 25c, and the spool 25
It is assumed that the port 25a is connected to the port 25b when d goes left in the figure, and the port 25a is connected to the port 25c when the spool 25d goes right in the figure.

In the spool 25d, the force exerted by the converter pressure P _C acting on the pressure receiving area difference of the spool land in the chamber 25e and the force exerted by the lock-up pressure P _{L / U} acting on the pressure receiving area difference of the spool land in the chamber 25f. And in response to the force exerted by the control pressure P _S acting on the left end surface of the spool in the chamber 25g, the control pressure P _S is controlled by the control pressure generation circuit 28.
And the solenoid valve 29 is used to make the following.

That is, the control pressure generating circuit 28 has one end 2
Reference pressure from 8a (for example, line pressure in the case of automatic transmission) P
_L is supplied, and this line pressure is applied to the orifices 28c and 28d.
The other end 28b of the circuit 28 is drained through. By determining the drain amount by the duty-controlled solenoid valve 29, a control pressure P _S can be created between the orifices 28c and 28d, and this is guided to the chamber 25g by the circuit 30.

The solenoid valve 29 is provided with a plunger 29a and a solenoid 29b for moving the solenoid 29b to the left when energized. By depressing the solenoid 29b, the plunger 29a is pushed away by the drain working fluid from the drain opening end 28b. The drain is allowed and the drain opening end 28b is closed by moving the plunger 29a to the left when the solenoid 29b is energized. The energization (energization) to the solenoid valve solenoid 29b is duty-controlled by a command from a lockup control computer 31 that performs lockup control of the torque converter, which is the object of the present invention. Here, when the duty (%) from the computer 31 to the solenoid 29b is small, the solenoid valve 29 causes the drain opening end 28b.
Is short, the control pressure P _S therefore becomes a very low constant value determined only by the pressure receiving area difference between the orifices 28c and 28d as shown in FIG. As the duty (%) becomes larger, the solenoid valve 29 becomes the drain opening end 28 for a long time.
As a result, the control pressure P _S gradually increases as shown in FIG. 3 and finally becomes equal to the line pressure P _L.

In FIG. 2, as the control pressure P _S rises, this control pressure causes the spool 25d to move to the right as shown in FIG. 4 (a) so that the port 25a is gradually and largely communicated with the port 25c, and the lock-up pressure P _S is increased. _{L / U} decreases. On the other hand, as the control pressure P _S decreases, the spool 25d will move to the position shown in FIG.
As shown in the left direction, the port 25a is gradually and widely communicated with the port 25b, and the lockup pressure P _{L / U} rises. By the way, since the control pressure P _S increases as the duty (%) increases as shown in FIG. 3, the lockup pressure P _{L / U}
Is kept equal to the converter pressure P _C in a region where the duty (%) is small as shown in FIG. 5, decreases as the duty (%) increases, and finally changes to zero. Then, the lockup pressure P _{L / U} is the converter pressure P
When the lockup clutch 22 is set to the maximum value equal to _C , the lockup clutch 22 is released because the pressures in the chambers 13d and 24 are equal, and the torque converter 13 is operated in the converter state with the maximum slip amount, and the lockup pressure P _{L / As U} decreases, the pressure difference between the pressure P _C in the chamber 13d and the pressure in the lock-up chamber 24 increases in the lock-up clutch 22, so that the lock-up clutch 22 is gradually slip-engaged to increase the binding force, resulting in the slip of the torque converter 13. gradually decreases the amount, the lock-up clutch 22 when the lock-up pressure P _{L / U} becomes zero is fully engaged by the converter pressure P _C in the chamber 13d, to function the torque converter 13 with a lock-up state of the slip amount zero.

The lock-up control computer 31 is operated by the power source + V, and a signal from the temperature sensor 32 as a working fluid temperature detecting means for detecting the hydraulic oil temperature C of the automatic transmission, the engine, and the rotation speed Ne (input element). 13a) and a signal from the rotation sensor 33 that detects the rotation speed of the gear 13a and the output rotation speed No of the gear transmission 42 (the rotation speed of the output element 13b is obtained by multiplying this rotation speed by the gear ratio of the gear transmission 42). A signal from a rotation sensor 34 for detecting, a signal from a throttle opening sensor (power source load detecting means) 35 for detecting a throttle opening TH of the engine 10, and a gear position for detecting a gear position G of a gear shift mechanism 42. Receiving the signals from the sensors (gear position detecting means) 43, the duty control of the solenoid valve 29 is performed as follows.

6 and 7 show a control program executed by the computer 31 for lock-up control. FIG. 6 shows a main routine which is repeatedly executed by an interrupt signal input at a constant time interval in step 50. FIG. 7 shows the subroutine.

First, to explain the main routine of FIG.
In step 51, the operating oil temperature C of the automatic transmission is read, and then in step 52, it is judged from the oil temperature C whether or not the warm-up operation is being performed. If so, the control proceeds to step 53 because the operation of the engine 10 is unstable, where the lockup clutch 22 is released and then the next step 54 is performed.
Then, the control is ended once. When releasing the lock-up clutch 22, the output duty is set to 0%, so that the lock-up pressure P _{L / U as} shown in FIG.
Is set to the maximum value equal to the converter pressure P _C, and the lockup clutch 22 is released, as is apparent from the above description.
In this case, the torque converter 13 functions in the converter state, and the unstable operation of the engine 10 can be supplemented by the torque increasing function and the torque fluctuation absorbing function.

When it is determined in step 52 that the warm-up operation is completed, the control proceeds to step 55, in which the output speed No of the gear speed change mechanism 42 is read, and the vehicle speed V is obtained based on this. Therefore, step 55 serves as a vehicle speed detecting means. In the next step 56, at least this vehicle speed V
It is determined whether it is the lockup area or the converter area based on.

If it is determined in step 56 that it is in the converter region, the control proceeds to step 53, where the torque converter 13 is made to function in the converter state as required by releasing the lockup clutch 22 as described above.

If it is determined in step 56 that the lockup region is present, the control proceeds to step 57, in which it is first determined whether or not the lockup region has been changed due to the region change, that is, the previous converter region has become the lockup region this time. It is determined whether or not If so, control proceeds to step 58.
7, the control program described later with reference to FIG. 7 is executed to perform the release-> engagement control of the lockup clutch 22 which is the object of the present invention.
3 is changed from the converter state to the lockup state. Otherwise, step 57 selects step 59, where it is determined whether or not there is a gear change depending on whether the gear position G has changed to indicate a gear change in the lockup region. When there is a gear shift in the lock-up region, the torque converter 13 should be in the converter state in the lock-up region in order to prevent a gear shift shock from the gear shift command to the completion of the gear shift. Since 13 should be returned from the converter state to the lockup state, it is determined in step 60 whether or not a predetermined time T ₁ has elapsed from the shift command,
Until the predetermined time T ₁ elapses, the shift is incomplete T and the control is advanced to step 53 to keep the torque converter 13 in the converter state. When the predetermined time T ₁ has elapsed, the shift is completed and the control is advanced to step 58. Return 13 to the lockup state.

If step 59 determines that there is no gear change,
The control proceeds to step 61, where the lockup clutch 22
To join. For this combination, the output duty is 1
As shown in FIG. 5, the lockup pressure P _{L / U is set} to zero, and the lockup clutch 22 is completely engaged, as is apparent from the above-mentioned process. In this case, the torque converter 13 keeps the lock-up state in the lock-up region as required and there is no slip, so
The fuel efficiency improvement effect of can be achieved.

Next, the release-> engagement control of the lockup clutch 22, which is to be performed in step 58, that is, the lockup control of the torque converter 13, which is the object of the present invention, will be described.

This lockup control is executed by the control program shown in FIG. 7. First, in step 71, the gear position G and the throttle opening TH are read. Then, in step 72, the engine speed (the speed of the pump impeller 13a) Ne is read, and in the next step 73, the gear ratio i of the gear transmission 42 based on the gear position G is multiplied by the output speed No of the mechanism 42. Then, the rotational speed N _T (N _T = i × No) of the turbine runner 13b is calculated. Next, at step 74, the torque converter slip amount ΔN is changed to ΔN =
It is calculated by Ne- _NT .

Further, in steps 75 to 85, the lockup clutch is engaged and advanced as follows. First,
The feedback constant K used to obtain the current solenoid drive duty D (NEW) as in step 84 is determined as shown in the control map of FIG. 8 in steps 75 to 83 corresponding to the feedback constant changing means. In step 75, it is checked whether the gear position G is the fourth speed, which is the highest speed, or the other first, second, and third speeds. In the case of the fourth speed, it is checked in step 76 whether or not the hydraulic oil temperature C is a high temperature exceeding the set temperature Cs, and in step 77, it is checked whether or not the engine is in a high load operation in which the throttle opening TH exceeds the set opening THs. If the temperature is high and the load is high, the feedback constant K is set to K in step 78.
_4H is set, otherwise, as long as it is the fourth speed, the feedback constant K is set to K _4L in step 79.

When it is determined in step 75 that the gear position G is the first speed, the second speed, and the third speed other than the highest speed, the hydraulic oil temperature C exceeds the set temperature Cs in step 80. It is checked whether or not the temperature is high and whether or not the throttle opening TH is a high load operation in which the throttle opening TH exceeds the set opening THs in step 81. If the temperature is high and the load is high, step 82
In step 83, the feedback constant K is set to K _3H. Otherwise, in step 83, the feedback constant K is set to K _3L .

In step 84 corresponding to the lock-up control means, the feedback constant K determined as described above is used, and the previous solenoid drive duty D (O
The duty value higher than LD) by the product of the torque converter slip amount ΔN and the feedback constant K is set as the current solenoid drive duty D (NEW). Then, in step 85, this duty value D (NEW) is output to the solenoid valve solenoid 29b. Thus,
The solenoid drive duty D (NEW) increases at a speed according to the product of the torque converter slip amount ΔN and the feedback constant K, and the lockup clutch 22 can be engaged and advanced at a corresponding speed.

By the way, as described above,
Feedback constant relating to the speed of engagement of the clutch 22
K given in advance as K in FIG._4H, K_4L, K_3H, K
_3LIs determined as follows. That is, for high speed gear positions
Feedback constant K_4H, K _4LFor the low gear position
Feedback constant K_3H, K_3LLarger than
The speed at which the clutch is engaged increases at high gear positions.
I will The reason is that the higher the gear position, the more engine rotation
As a result of the lower number, the power including engine and transmission is reduced.
The rotational inertia energy of the train becomes smaller
Lockup shock is small and lockup clutch
This is because there is no hindrance even if they are fastened at a relatively high speed.

Even at the same gear position, the higher the transmission operating oil temperature C, the larger the feedback constant,
Therefore, K _4H > K _4L and K _3H > K _3L are set so that the engagement progress speed of the lockup clutch is increased at a high oil temperature. The reason is that the higher the hydraulic oil temperature C, the lower the viscosity of the hydraulic oil, and the smaller the friction loss of the transmission. As a result, the rotation inertia of the transmission becomes smaller, the lock-up shock is smaller, and the lock-up clutch is opened. This is because there is no problem even if they are fastened at a relatively high speed.

Further, even at the same transmission gear position, the higher the throttle opening TH, the larger the feedback constant,
Also in this sense, K _4H > K _4L and K _3H > K _3L are set so that the engagement progress speed of the lock-up clutch is increased at a high throttle opening (high load). The reason is that the larger the throttle opening TH, the larger the engine output torque and the harder it becomes to engage the lock-up clutch. Therefore, if the lock-up clutch is engaged at a low speed during this operation, the fuel efficiency improvement effect due to the lock-up is improved. This is because it is significantly reduced.

The condition of the vehicle speed V is not shown in FIG.
In this example, K depends on the vehicle speed V._4H, K _4L, K_3H, K_3LBut
Although it is assumed that the vehicle speed V does not change, the vehicle speed V does not exceed the set vehicle speed Vs.
The feedback constant varies depending on whether it exceeds or is less than
Needless to say, it can be done. In this case, the vehicle speed
The higher the V, the larger the feedback constant and
At the vehicle speed, engage the lockup clutch at a relatively high speed.
To do so. The reason is that the higher the vehicle speed, the more power train
Has a high rotational speed and its rotational inertia energy is large.
I don't care about lock-up shock
It is.

Further, in this example, in order to save memory, the fourth speed,
Although the feedback constants are only switched according to the other 1st speed to 3rd speed, it is preferable to change the feedback constant between the 1st speed to the 3rd speed because more detailed control can be realized. Of course.

Incidentally, in addition to FIG. 8, the fourth
If the operating oil temperature rises during high throttle opening operation with speed selected, the lockup clutch is most engaged because the engine output torque is high and the operating oil viscosity is low due to the high throttle opening. Therefore, the feedback constant K is set to a relatively large value K _4H so that the lockup clutch can be engaged at a relatively high speed even at the same fourth speed as in the low load and low temperature state. By the way, the third
When the speed is selected, the engine speed is higher and the rotational inertia energy of the engine is higher than when the fourth speed is selected. Therefore, at the same lock-up clutch engagement speed as in the fourth speed, a push-up shock occurs during engagement, The feedback constant K is set to K _3H , K _3L smaller than K _4H , K _4L.
Set to. When the operating oil temperature becomes high during the high throttle opening operation even at the same third speed, the engine output torque is large because of the high throttle opening and the viscosity of the operating oil is low. It is difficult to conclude. Therefore, the feedback constant K is set to K _3H , which is larger than K _3L , in order to engage the lockup clutch at a relatively high speed even in the same third speed as in the case of low load and low temperature. Further, in the above embodiment, the hydraulic oil temperature C is directly detected by the temperature sensor 32, but it may be estimated from the temperature related to the hydraulic oil temperature, such as estimation from the engine cooling water temperature. Further, although the gear position G is detected by the gear position sensor 43, it may be a gear ratio calculated from the input / output rotation of the transmission or a gear ratio when commanding a shift calculated by the control unit.

[0058]

As described above, according to the first aspect of the present invention, the lock-up control device is configured to change the feedback constant according to the selected gear position of the transmission.
The lockup clutch engagement speed determined by the feedback constant is changed according to the selected gear position of the transmission, and a different lockup clutch engagement speed that is different for each selected gear position can be achieved. In such a range that does not occur, it is possible to perform control such that the lockup clutch is engaged fastest, and it is possible to reduce the lockup shock and improve the fuel efficiency by the lockup.

According to the lock-up control device of the second aspect of the invention, as described in claim 2, the feedback constant is changed so that the engagement speed of the lock-up clutch becomes faster at higher gear positions. The higher the gear position is, the lower the speed of the power source will be,
In response to the decrease in the rotation inertia of the power train including the power source and the transmission to reduce the lock-up shock, the engagement speed of the lock-up clutch is increased, and the engagement speed of the lock-up clutch is unnecessarily increased. It is possible to prevent the fuel consumption improving effect due to the lockup from being lowered at a later time.

As described in claim 3, the lock-up control device according to the third aspect of the present invention is, in addition to the first or second aspect of the invention, configured to change the feedback constant even in accordance with the temperature of the transmission working fluid. Therefore, the engagement speed of the lockup clutch determined by the feedback constant is changed depending on the temperature of the working fluid, and a suitable lockup clutch engagement speed that differs for each temperature of the working fluid is also achieved. As a result, the control such as engaging the lock-up clutch at the fastest speed within the range where the lock-up shock does not occur is possible more than in the first invention or the second invention, and the lock-up shock is reduced and the fuel consumption by the lock-up is improved. The improvement effect can be more reliably achieved at the same time.

According to the fourth aspect of the present invention, the lock-up control device is configured to change the feedback constant so that the engagement speed of the lock-up clutch becomes faster as the working fluid temperature becomes higher. Corresponding to the fact that the higher the fluid temperature, the smaller the friction loss of the transmission due to the decrease in viscosity, the smaller the rotation inertia of the transmission and the smaller the lock-up shock.
Since the engagement speed of the lockup clutch is increased, it is possible to prevent the engagement speed of the lockup clutch from being unnecessarily slowed and prevent the fuel consumption improving effect due to the lockup from decreasing.

As described in claim 5, the lock-up control device according to the fifth aspect of the invention is added to the first or second aspect of the invention, and is configured to change the feedback constant also according to the load state of the power source. Therefore, the engagement speed of the lockup clutch determined by the feedback constant is changed depending on the power source load state, and it is possible to achieve a suitable lockup clutch engagement speed that is different for each power source load state. In addition, the control such as engaging the lockup clutch most quickly within the range where lockup shock is not generated is possible more than the first invention or the second invention, and the effect of reducing the lockup shock and improving the fuel efficiency by the lockup is achieved. It is possible to achieve both and more reliably.

According to the sixth aspect of the lock-up control device of the present invention, the feedback constant is changed so that the engagement speed of the lock-up clutch becomes higher as the power source load becomes higher. As the load increases, the output torque of the power source increases and it becomes difficult to engage the lockup clutch, so that the engagement speed of the lockup clutch is increased, and the engagement speed of the lockup clutch is unnecessarily increased. It is possible to prevent the fuel efficiency improvement effect due to lockup from being lowered by delaying.

The lock-up control device of the seventh invention is, in addition to the fifth invention or the sixth invention, configured to change the feedback constant depending on the vehicle speed as described in the seventh aspect. The engagement speed of the lockup clutch that is determined by the constant will be changed depending on the vehicle speed, and it is possible to achieve a suitable engagement speed of the lockup clutch that differs for each vehicle speed, within a range that does not cause a lockup shock. Control such as engaging the lockup clutch at the fastest speed is possible more than in the fifth or sixth invention, and it is possible to more reliably achieve both the reduction of the lockup shock and the fuel consumption improvement effect of the lockup. .

According to the eighth aspect of the lock-up control device of the present invention, the feedback constant is changed as the vehicle speed increases so that the engagement speed of the lock-up clutch is increased. In response to the fact that the rotational speed of the power train including the power source and the transmission is high and the rotational inertia energy becomes large and the lock-up shock becomes unnoticeable, the engagement speed of the lock-up clutch will be increased, It is possible to prevent the fuel consumption improving effect due to the lockup from being lowered by slowing the engagement speed of the lockup clutch as necessary.

The lock-up control device of the ninth invention is, in addition to the third invention or the fourth invention, as described in claim 9, configured to change the feedback constant depending on the power source load and the vehicle speed. Therefore, the engagement speed of the lockup clutch, which is determined by the feedback constant, is changed depending on the power source load condition and the vehicle speed. It is possible to achieve such control that the lockup clutch is fast engaged within the range in which the lockup shock is not generated.
This is possible even more than the invention, and it is possible to more surely achieve both the reduction of the lockup shock and the effect of improving the fuel efficiency due to the lockup.

According to a tenth aspect of the present invention, as in the tenth aspect of the present invention, in the ninth aspect of the present invention, the higher the power source load is, the more the feedback constant is changed so that the engagement speed of the lockup clutch becomes faster. According to the configuration, as the load on the power source increases, the output torque of the power source increases and it becomes difficult to engage the lockup clutch, so that the engagement speed of the lockup clutch is increased, which is unnecessary. Further, it is possible to prevent the fuel consumption improving effect due to the lockup from being lowered by slowing the engagement speed of the lockup clutch.

According to the eleventh aspect of the present invention, as in the eleventh aspect of the present invention, in the ninth aspect of the present invention, the feedback constant is changed so that the higher the vehicle speed, the faster the lockup clutch engaging speed becomes. Therefore, the higher the vehicle speed, the higher the rotation speed of the power train including the power source and the transmission, and the greater the inertia energy of the rotation. Since the speed is increased, it is possible to prevent the engagement speed of the lockup clutch from being unnecessarily slowed and prevent the fuel consumption improving effect due to the lockup from decreasing.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a lockup control device for a torque converter according to the present invention.

FIG. 2 is a control system diagram showing an embodiment of a lockup control device according to the present invention.

FIG. 3 is a diagram showing a change characteristic of control pressure with respect to a solenoid drive duty in the same example.

FIG. 4 is an operation explanatory view of the lockup control valve in the example.

FIG. 5 is a diagram showing a change characteristic of lockup pressure with respect to a solenoid drive duty in the same example.

FIG. 6 is a main routine showing a flowchart of lockup control executed by a computer in the same example.

FIG. 7 is a flowchart showing a subroutine of the lockup control.

FIG. 8 is a diagram illustrating a feedback constant setting map.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 power source 2 input element 3 transmission 4 output element 5 lockup clutch 6 torque converter 7 lockup control means 8 gear position detecting means 9 feedback constant changing means 10 engine (power source) 13 torque converter 13a pump impeller (input element) 13b Turbine runner (output element) 14 Torque converter output shaft 17 Oil pump 22 Lockup clutch 24 Lockup chamber 25 Lockup control valve 28 Control pressure generation circuit 29 Electromagnetic valve 31 Lockup control computer 32 Oil temperature sensor (working fluid temperature) Detection means) 33 engine speed sensor 34 gear speed change mechanism output speed sensor 35 engine throttle opening sensor (power source load detection means) 42 gear speed change mechanism 43 gear position sensor (gear position detection means)

Front page continued (72) Inventor Hideharu Yamamoto 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72) Inventor Shigeru Ishii 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72) Invention Person Yoshihide Shinso 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72) Inventor Mitsuo Murata 2- Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd.

Claims (11)

[Claims] 1. A lockup clutch capable of directly connecting an input element driven by a power source, an output element driven by a working fluid stirred by the power source to transmit power to a transmission, and a direct connection between these input / output elements. A lockup control device for a torque converter, comprising: lockup control means for engaging the lockup clutch at a speed according to a product of a torque converter slip amount and a feedback constant. A lock-up control device for a torque converter, comprising: a gear position detecting means for detecting a position; and a feedback constant changing means for changing the feedback constant according to the gear position detected by the means. 2. The lockup of a torque converter according to claim 1, wherein the feedback constant changing means is configured to change the feedback constant such that the engagement speed of the lockup clutch becomes faster at a higher gear position. Control device. 3. The working fluid temperature detecting means for detecting the temperature of the working fluid according to claim 1 or 2, wherein the feedback constant changing means is adapted to perform the feedback even in accordance with the working fluid temperature detected by the means. A lock-up control device for a torque converter, which is configured to change a constant. 4. The torque converter according to claim 3, wherein the feedback constant changing means is configured to change the feedback constant such that the engagement speed of the lockup clutch becomes faster as the working fluid temperature becomes higher. Lockup controller. 5. The power source load detecting means for detecting a load state of the power source according to claim 1 or 2, wherein the feedback constant changing means is adapted to detect the power source load detected by the means. A lock-up control device for a torque converter, which is configured to change a feedback constant. 6. The torque converter according to claim 5, wherein the feedback constant changing means changes the feedback constant such that the higher the power source load, the faster the engagement speed of the lockup clutch. Lockup controller. 7. The vehicle speed detecting means for detecting a vehicle speed according to claim 5 or 6, wherein the feedback constant changing means is configured to change the feedback constant according to the vehicle speed detected by the means. A lock-up control device for a torque converter, characterized by: 8. The lock of a torque converter according to claim 7, wherein the feedback constant changing means is configured to change the feedback constant such that the higher the vehicle speed, the faster the engagement speed of the lockup clutch. Up control device. 9. The power source load detecting means for detecting a load state of the power source and the vehicle speed detecting means for detecting a vehicle speed according to claim 3 or 4, wherein the feedback constant changing means is provided by the means. A lock-up control device for a torque converter, characterized in that the feedback constant is also changed depending on the detected power source load and vehicle speed. 10. The torque converter according to claim 9, wherein the feedback constant changing means is configured to change the feedback constant such that the engagement speed of the lockup clutch becomes faster as the power source load becomes higher. Lockup controller. 11. The torque converter according to claim 9 or 10, wherein the feedback constant changing means changes the feedback constant such that the engagement speed of the lockup clutch becomes faster as the vehicle speed becomes higher. Lockup controller.