JPH01141273A - Lock-up clutch controller for automatic transmission - Google Patents

Abstract

PURPOSE:To suppress lowering of fuel consumption and to reduce torque impact during deceleration by setting a target slippage of a slip control means corresponding to deceleration. CONSTITUTION:In a controller 10, a slip control means 7 receives outputs from a speed change operating means 105 and a lock-up judging means 106, an engine rotation signal and a vehicle speed signal, then sets a target slippage corresponding to operating condition and controls fastening force of a lock-up clutch such that the target slippage can be obtained. A correcting means 108 varies the target slippage to be set through a slip control means 107 corresponding to deceleration in fuel-cut region based on outputs from a fuel-cut judging means 102 and a deceleration judging means 104. Consequently, lowering of fuel consumption can be suppressed and the torque impact can be reduced under deceleration.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a lock-up clutch control device for an automatic transmission;
In particular, the present invention relates to a device for controlling a lock-up clutch so that the pump rotational speed and the turbine rotational speed are within a predetermined rotational speed difference during deceleration.

(Prior art) A lock-up control device for an automatic transmission is disclosed in JP-A No. 5, for example.
It is widely known as described in Japanese Patent No. 8-68539.

In such vehicles, lock-up prevents the engine speed from dropping during deceleration,
Things that improve fuel efficiency are known. In addition, there is also a known method that does not completely lock up, but instead controls the lock-up clutch to slip so that the pump rotation speed and turbine rotation speed are within a predetermined rotation speed difference, thereby reducing torque shock during deceleration. ing.

(Problems to be Solved by the Invention) However, in such a device, the target value of the slip amount is constant regardless of the deceleration, so it is not possible to perform optimal control according to the deceleration state. For example, if the deceleration is large, the torque shock may not be sufficiently reduced, especially in the early stages of deceleration. Further, if the target value is increased, torque shock can be reduced, but this is disadvantageous in terms of fuel efficiency. This tendency is particularly noticeable in the fuel cut region.

The present invention has been made in view of the above, and is a lock-up clutch control device for an automatic transmission that provides optimum control according to the deceleration state, for example, suppresses deterioration of fuel efficiency as much as possible and reduces torque shock during deceleration. The purpose is to provide

(Means for Solving the Problems) In order to achieve the above object, the present invention controls a lock-up clutch so that the pump rotation speed and the turbine rotation speed are within a predetermined rotation speed difference during deceleration. a deceleration detection means for detecting deceleration; and a slip control means for setting a target value of the slip amount according to the operating condition and controlling the engagement force of the lock-up clutch so that the slip amount becomes the target value. , receives the output of the deceleration detection means,
The present invention is characterized by comprising a correction means for changing the target value set by the slip control means in accordance with deceleration.

(Function) During deceleration, the target value of the slip amount by the slip control means is set according to the deceleration, so that optimal slip lockup control can be performed.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

In FIG. 1 showing the overall configuration of a lock-up clutch control device for an automatic transmission, reference numeral 1 denotes an engine body, to which an intake passage 2 and an exhaust passage 3 are connected.

The intake passage 2 is provided with an air cleaner (not shown), an air flow meter 4, a throttle valve 5, and an injector 6 in this order from the upstream side, and the exhaust passage 3 is provided with a catalyst device 7. There is.

10 is a controller which receives the intake air amount signal Q air from the air flow meter 4 and the engine rotation speed signal N from the rotation speed sensor 11, and is connected to an injection pulse calculation means 101 for calculating a fuel injection pulse, and an engine rotation speed signal Ng.
and fuel cut determination means 102 for determining whether or not the throttle relationship signal Tvo from the throttle sensor 12 is in the fuel cut region;
2, and a fuel cut execution means 1o3 that prohibits fuel injection from the injector 6 in the fuel cut region.

The controller 10 also includes a deceleration determining means 104 that receives the throttle opening signal and determines deceleration, and receives the throttle opening signal and the vehicle speed signal from the vehicle speed sensor 13 and calculates the gear stage of the automatic transmission 14. Shift calculation means 105 outputs a gear selection signal to the shift solenoid, and lock-up determination means 1 receives the throttle opening signal and vehicle speed signal and determines whether or not the vehicle is in the lock-up region.
Further, upon receiving the outputs of the shift calculation means 105 and the lock-up determination means 106, as well as the engine rotational speed signal and the vehicle speed signal, a target value of the amount of slip is set according to the driving condition, and the amount of slip is set as the target value. A slip control means 1 for controlling the engagement force of the lock-up clutch as shown in FIG.
07, and a correction means 108 which receives the outputs of the fuel cut determination means 102 and deceleration determination means 104 and changes the target value set by the slip control means 1.7 in accordance with the deceleration in the fuel cut region. and has.

Note that lockup control is performed as follows.

The structure of the torque converter and its control hydraulic circuit will be explained with reference to FIG. A rotating pump 24 , a turbine 25 rotatably provided on the other side of the case 23 so as to face the pump 24 and rotationally driven via hydraulic oil by the rotation of the pump 24 ; A starter 26 is interposed between the turbine 25 and the starter 26, which increases the torque when the speed ratio of the turbine rotation speed to the pump rotation speed is below a predetermined value. Lockup clutch 2
7. The rotation of the turbine 25 is outputted by a turbine shaft 28 and inputted to a speed change gear mechanism (not shown), and the lock-up clutch 27 is connected to the turbine shaft 28 and is connected to the case 23. When fastened, the engine output shaft 22 and the turbine shaft 28 are connected through the case 23.
It is designed to be directly connected to

Further, hydraulic oil is introduced into the torque converter 21 through a main line 29 led from an oil pump (not shown) via a lock-up valve 30 and a converter inline 31, and the pressure of this hydraulic oil is The lock-up clutch 27 is always biased in the engagement direction, and the lock-up valve 3 is provided in the space 32 between the clutch 27 and the case 23.
A lock-up release line 33 led from 0 is connected, and the lock-up clutch 27 is released when hydraulic pressure (release pressure) is introduced from the line 33 into the space 32. Further, a converter outline 36 is connected to the torque converter 21 to send hydraulic oil to an oil cooler 35 via a pressure holding valve 34.

On the other hand, the lock-up valve 3o has a spool 30a.
and a spring 30b that urges this to the right in the drawing, and a pressure regulating port 30d and a drain port 30e to which the main line 29 is connected on both sides of the port 30c to which the lock-up release line 33 is connected. is provided.

Further, a control line 37 for applying pilot pressure to the spool 30a is provided at the right end of the valve 30 in the drawing.
A duty solenoid valve 39 is installed in a drain line 38 branched from the control line 37. This duty solenoid valve 39 is turned on and off at a duty rate according to an input signal.
By repeating FF to open and close the drain line 38 in extremely short cycles, the pilot pressure in the control line 37 is adjusted to a value corresponding to the duty rate6.Then, this pilot pressure is applied to the spool of the lock-up valve 30. A force is applied to the spool 30a in a direction opposing the biasing force of the spring 30b, and the spring 3 is applied to the spool 30a.
The release pressure in the lock-up release line 33 acts in the same direction as the urging force of 0b, and the spool 30a moves due to the force relationship between these oil pressures or urging forces, and the lock-up release line 33 moves toward the main line. 29
By communicating with the pressure regulating port 30d or the drain port 30e, the lockup release pressure is controlled to a value corresponding to the pilot pressure, that is, the duty rate of the duty solenoid valve 39. Here, when the duty rate is at its maximum value, the amount of drain from the control line 37 is at its maximum, and the pilot pressure or release pressure is at its minimum, so that the lock-up clutch 27 is completely engaged, and the duty rate is at its maximum value. At 100%, the drain amount becomes the minimum, and the pilot pressure or release pressure becomes the maximum, so that the lock-up clutch 27 is completely released. And the maximum value is 10
At a duty rate of 50%, which is between 0% and the minimum value O%, the lock-up clutch 27 is in a slip state, and in this state, the release pressure is adjusted according to the duty rate, thereby increasing the slip amount of the lock-up clutch 27. is now under control.

Next, the flow of processing by the controller 10 will be explained with reference to FIGS. 4(a) and 4(b).

When started, first, the throttle opening degree Tvo, the engine speed NIl, and the intake air amount Qair are read (step S1), and the injection pulse T is calculated (step S2).

Then, determine whether the rate of change of the throttle opening degree Tvo with respect to time t is negative, that is, d T Vo/d
It is determined whether t < 0 (step Sa).

If the above rate of change is negative, set FLAG to 1 (
Step 54)-' On the other hand, if the rate of change is positive, set FLAG to O, step SS), determine the deceleration line (step S6), and then determine whether or not to perform a fuel cut based on FIG. A determination is made (step S7).

If it is in the region where fuel cut is to be performed, the fuel cut is executed (step 5S), whereas if it is not in the region where fuel cut is to be performed, the injection pulse T set in step S2 is executed.
Then, fuel is injected (step S9).

Thereafter, the gear position of the automatic transmission 14 is calculated (Step 5zo), and a gear selection signal is output based on the calculation (Step S1). ), it is determined whether or not FLAG=1 (step S1□), and if FLAG=1, it is then determined whether or not it is the moment when FLAG=1 (step 51a). , at the moment when FLAG=1, it means that the vehicle is in a deceleration state.Because of the need to change the amount of slip, the duty ratio is set to 50, for example, in step 5t4), and the initial value is changed to set the current vehicle speed. Value V. Determine whether or not the following is true (Step 5)
1s) - Vehicle speed is set value V. If it is below, it is a low speed range, and in order to improve the effectiveness of engine braking, the smaller the amount of slip, the better, so normal control is performed and the rotation difference Δ is set as the target value.
Set N0=A0 (step S), while setting value V,
If it exceeds, calculate the rate of change dTVo/dt described above (step 5ty).

Based on the result, the rotational difference ΔNO (=A) as a target value is calculated based on FIG. 6 (step 51s), and the process moves to step Sts.

If it is determined in step 813 that it is not the moment when FLAG=1, the process immediately moves to step Stg without passing through steps 814 to StS.

In step StS, it is determined whether ΔN (1=A (3), and if ΔNo=Ao, step S
While moving to 2□, if 8 No = A, then target value ΔN
. The value ΔN obtained by subtracting the fixed amount a from (=A) (1-a is set as the new target value ΔNo (step 5211)), 1 is added to the count number T of the timer, (step 521)
The process moves to step S22.

In step S22, the turbine rotation speed NT is calculated from the vehicle speed and gear ratio, and then it is determined whether the difference between the turbine rotation speed NT and the engine rotation speed NE is less than the target value ΔN.
That is, it is determined whether or not (step 523).

If it is less than the target value ΔNo, the duty ratio Duty is increased, that is, Duty + Δd (Δd: set value) (step 524), and the duty ratio Duty is output as a slip control signal (step 5zs).
- If it is not less than ΔNo, it is determined whether or not there is a difference in the rotation speed (step 5zs), and the difference duty ratio Duty is decreased, that is, Duty -
Δd (step 527), if not larger.

The process immediately moves to step SO5.

After the process of step SO5, it is determined again whether ΔN,=Ao (step 5zs), and ΔN.

If = A0, the process ends as is, while if ΔNo = Ao, it is determined whether the count number T is smaller than the set count number calculated during the calculation in step 5ill (step 829), tJS. If so, the target value ΔN0 has not been reached, so return to step S2□, repeat the processes of steps Ski to S29, and if it is not smaller, reset the count number T and set it to O (step 5ao)
,finish.

Note that if FLAG=1 is not determined in step S□2, the duty ratio is set to 100 and step S
3□), the duty ratio is output as a control signal, step S3□), the lockup is released, and the process ends.

In addition, in the above embodiment, in order to emphasize shock, the amount of slip is increased when the deceleration is large, and the amount of slip is decreased when the deceleration is small, but conversely, when the deceleration is large However, if the slip amount is increased, the engine speed may drop faster and the engine may stall. Therefore, contrary to the above embodiment, the slip amount may be reduced. , only in the early stages of deceleration when torque shock is most noticeable,
Although the amount of slip is changed, control may be performed over the entire slip region, and open control may be used instead of focusing on feedback control.

(Effects of the Invention) As described above, the present invention changes the target value of the slip amount set by the slip control means in accordance with the deceleration, thereby suppressing deterioration of fuel consumption as much as possible and It is possible to improve reliability and reduce torque shock during fuel cut. This is particularly effective in the fuel cut region where torque shock is large.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall configuration diagram of a lock-up clutch control device for an automatic transmission, and FIG.
FIG. 3 is a block diagram showing the configuration of the controller, FIG. 3 is an explanatory diagram of the lock-up clutch, FIG. FIG. 6 is a diagram showing the relationship between the rate of change in throttle opening and slip ratio. 10... Controller, 102... Fuel cut determining means, 104... Deceleration determining means, 107... Slip control means, 108...
...Correction means. Figure 1 Taku Figure 5

Claims (1)

[Claims] (1) In a device that controls a lock-up clutch so that the pump rotation speed and the turbine rotation speed are within a predetermined rotation speed difference during deceleration, there is a deceleration detection means for detecting deceleration, and a slip-up clutch that detects deceleration according to the operating state. a slip control means for setting a target value of the slip amount and controlling the engagement force of the lockup clutch so that the slip amount becomes the target value; and a slip control means that receives the output of the deceleration detection means and is set by the slip control means A lock-up clutch control device for an automatic transmission, comprising a correction means for changing a target value according to deceleration.