JP2014199072A - Gear change controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CVT gear change control method capable of suppressing degradation in fuel economy due to a delay in gear change while simultaneously reducing a shift shock during upshift gear change.SOLUTION: A gear change controller of the present invention is a gear change controller for a vehicle including a continuously variable transmission having a lockup control mechanism, executes upshift followed by lockup to set a gear change command value to a predetermined value lower than a maximum command value of a target gear change ratio for a predetermined time (X) including the time of engagement of a lockup clutch. The gear shift controller of the present invention calculates a difference between a sheave moving amount for predetermined time (Y) within the predetermined time (X) and a sheave target moving amount relative to the upshift. After completion of the upshift, a duty value correction corresponding to the difference is performed on a solenoid duty value for a gear change command value at a next upshift.

Description

The present invention relates to a shift control method for a vehicle having a continuously variable transmission, and in particular, in a lockup control at a low speed, a shift shock at the time of upshifting with a lockup clutch engaged is reduced and at the same time the shift is slow. The present invention relates to a CVT shift control device that can also suppress a decrease in fuel efficiency due to the engine.

Conventionally, in vehicles having a continuously variable transmission (hereinafter referred to as “CVT”) or the like, lockup control in which an engine and a turbine are directly connected by a lockup clutch in a medium to high speed range has been adopted in order to improve fuel efficiency. In recent years, lock-up control has been executed even at low vehicle speeds in order to further improve fuel efficiency.

In the lockup in the low speed range, if the gear is rapidly changed, the rotation effect due to the moment of inertia of the rotating object inside is large, and the shock at the completion of the engagement between the engine and the turbine is large.

In order to solve this problem, for example, Patent Document 1 discloses a shift control device that performs shift hydraulic pressure control in order to suppress a shift shock during an upshift with a lockup clutch engaged.

However, in the case of the shift control device of Patent Document 1, there is a problem that fuel consumption performance is lowered because the shift hydraulic pressure is lowered to suppress the shift shock and slipped to increase the shift time. On the other hand, if the shift time is shortened, the shock due to the moment of inertia cannot be reduced as described above.

JP 2005-299860 A

The present invention was created in view of the above problems, and the present invention reduces shift shocks during upshifting in the lockup clutch engaged state in lockup control at low speed, and at the same time slow shifts. It is an object of the present invention to provide a CVT shift control device that can suppress a decrease in fuel efficiency due to the above.

The present invention provided to solve the above-described problems is as follows.
A shift control apparatus for a vehicle including a continuously variable transmission having a lockup control mechanism. Further, the speed change control device performs an upshift with lockup, and sets the shift command value to a predetermined value lower than the maximum command value of the target gear ratio for a predetermined time (X) including when the lockup clutch is engaged. Set.

According to the present invention, for the upshift after engagement of the lockup clutch, the shift command value is temporarily set to a predetermined value (generally constant value) lower than the maximum command value of the target gear ratio for a predetermined time (X). Therefore, it is possible to eliminate a push-out shock due to inertia (moment of inertia) during upshifting.

Further, the shift control device of the present invention includes:
A difference between a sheave movement amount at a predetermined time (Y) within the predetermined time (X) and a target movement amount of the sheave with respect to the upshift is calculated, and after the upshift is completed, a shift command at the next upshift is calculated. It is also possible to perform duty value correction corresponding to the difference on the solenoid duty value with respect to the value.

According to the present invention, the difference between the sheave movement amount after completion of engagement of the lockup clutch and the target movement amount is learned, and is corrected and reflected in the shift command value at the time of upshift at the next lockup. Thus, it is possible to suppress variations in the amount of shift due to variations in solenoids (particularly variations in reaction time). Further, if the target moving amount of the sheave is set in accordance with the fast solenoid, it is possible to avoid a reduction in fuel consumption due to a delay in the upshift.

Combined with the above effects, according to the shift control device of the present invention, the present invention reduces the shift shock at the time of upshift with the lockup clutch engaged in the lockup control at low speed, and at the same time conflicts. As a result, it is possible to suppress a decrease in fuel efficiency due to slow shifting.

It is a term chart which shows the signal change etc. of each element in this transmission control apparatus. It is a graph which shows the relationship figure of sheave movement amount and correction | amendment (beta) (%). The control flow of this embodiment shown in the time chart of FIG. 1 is shown.

FIG. 1 is a term chart showing signal changes and the like of each element in the speed change control device.
From the upper stage, the shift command value (DQSC) as the first stage, the solenoid duty value (DS1) as the second stage, the engine speed (NE) as the third stage, the turbine speed (NIN) as the fourth stage, the fifth The gear ratio (RATIO) is shown as the stage, and the sheave movement amount (GRTO) is shown as the sixth stage.

The premise here is lock-up in a low speed range, and the vehicle is in a stopped state until time t0. The engine speed (NE) also increases as the vehicle speed is increased by stepping on the accelerator while the vehicle is stopped, and the turbine speed (NIN) follows and approaches this. At this time, the gear ratio remains fixed, and the low gear is normally selected. Then, the turbine rotational speed (NIN) catches up with the engine rotational speed (NE) and becomes the same rotational speed at time t1, and the engagement of the lockup clutch is completed.

When the lock-up clutch is engaged, the low gear shifts up because the fuel efficiency is poor. However, since an upshift after completion of engagement of the lockup clutch is slow, an upshift gear shift command is issued in advance. First, before the lock-up clutch is engaged, if the difference between the turbine speed (NIN) and the engine speed (NE) is equal to or less than a predetermined value, the gear shift is started (time t1) because the engagement is close. The When this shift start point t1, that is, when the lockup clutch comes into contact and begins to slip, the shift command value (DQSC) is suppressed to be lower than the maximum command value 1 (dotted line) at which the target gear ratio is achieved. The predetermined time (X) during which the shift command value (DQSC) is suppressed is referred to as a shift guard time (X), and is set from time t1 to t3 in FIG.

The duty value (DS1) of the upshift solenoid (upshift solenoid valve) is also set according to the shift command value (DQSC). This duty value is set to control the pressure of the upshift signal pressure. Since the shift command value (DQSC) is set low, the solenoid duty value (DS1) also becomes low (from time t1 to time t3). (See solid line). The shift command value (DSQC) 2 at the time of shift guard (X) is determined from a preset oil temperature and torque map (not shown).

A shift command (DQSC) is issued at time t1, and the engine speed (NE) and turbine speed (NIN) approach each other while further increasing the speed, and the engagement is completed at time t2. After the engagement is completed, the lockup state is established, and the engine speed (NE) and the turbine speed (NIN) proceed at the same speed. When the engagement is completed at time t2, an upshift is started as a response to the shift command (DSQC), and thereafter it can be seen that the engine and turbine rotation speeds (NE, NIN) are reduced. As described above, since the shift command value (DQSC) is suppressed when the lockup clutch is engaged (reference number 2), the shock caused by pushing out is reduced when the engagement is completed.

Further, there is a variation in the reduction speed of the engine and the turbine speed (NE, NIN) after the engagement of the lockup clutch is completed. This is due to variations in individual characteristics of the upshift solenoid. In FIG. 1, there are an upper limit value 3 (solid line) and a lower limit value 3 ′ (broken line) for the reduction speed of the engine and turbine speed (NE, NIN). It is shown. After the engagement is completed, the actual gear ratio (RATIO) also becomes smaller, that is, the gear ratio on the upshift side. At this time, the speed change ratio after a predetermined time (Y = time t4 to t3) also varies due to variations in the individual upshift solenoids as well as variations 3 and 3 ′ in the decrease speed of ethidine and turbine rotation speed (NE, NIN). Arise. In FIG. 1, an upper limit 4 (solid line) and a lower limit 4 '(dotted line) of the gear ratio reduction speed are shown. In the case of the lower limit 4 ', it is understood that the response of the upshift solenoid is slow, and it can be seen that there is a delay in the time until the gear ratio reduction starts compared to the response time in the case of the upper limit solenoid.

In the present embodiment, learning control is performed to eliminate the delay in shifting of the upshift solenoid that becomes the lower limit 4 '. This is because if the shift response is delayed, the decrease in the engine speed (NE) is also delayed (reference 3 '), so that the fuel efficiency is worse than that in the case of the upper limit 4. Therefore, the sheave movement amount (GRTO) is calculated so that the gear ratio (RATIO) at the time t3 is close to the upper limit 4 and the speed is increased. The sheave movement amount (GRTO) is calculated from the amount of change in the gear ratio (RATIO) with respect to the predetermined time (Y).

Then, the difference between the sheave movement amount (GRTO) at t3 and the sheave target movement amount is calculated, and the sheave is moved by the difference sheave movement amount (GRTO) L at time t3. The target sheave movement amount is the amount (upper limit 4) at the time of sheave movement in an upper limit product such as a solenoid that causes variation in the sheave movement amount (GRTO).

Further, it is added to the solenoid duty value (DS1) corresponding to the shift command value (DQSC) at the time of the next upshift by the correction β (%) of the duty value (DS1) corresponding to this difference L. The correction amount β (%) of the duty value (DS1) is calculated from the relationship diagram between the sheave movement amount and the correction β (%) shown in FIG.

As a result, the variation in the reaction time of the solenoid for the upshift can be corrected from the next upshift, and a reduction in fuel consumption due to a delay in the upshift can be prevented. Further, as described above, the shift command value (DQSC) is suppressed from the maximum shift value until time t3 in order to reduce shock when the lockup clutch is engaged, but after time t3, the maximum shift value 5 is gradually changed. The shift shock is reduced.

Next, FIG. 3 shows a control flow of the present embodiment shown in the time chart of FIG.
First, the engine speed NE and the turbine speed NIN are detected by an existing detection sensor or the like (STEP 2). Next, when the engine speed (NE) and the turbine speed (NIN) approach each other and the rotational speed difference becomes equal to or smaller than a predetermined value α, it is determined that the lockup clutch is immediately engaged (STEP 4). When engine speed (NE) -turbine speed (NIN) ≦ predetermined value α, shift start point (hour) t1 is set, and predetermined time (X) from time t1 to time t3 is determined from the maximum shift command value. It is set as a shift guard time (X) for transmitting a low shift command value. The shift guard time (X) is usually about 1 second.

Then, when the shift guard time (X) including the completion of engagement has elapsed from the shift start point t1 and reaches the time t2 (STEP 8), the gear ratio (RATIO) at the time t2 is detected (STEP 10), The sheave movement amount (GRTO) in a predetermined time (Y = t4 to t3) is determined from the gear ratio (RATIO) (STEP 12). A difference L between the sheave movement amount (GRTO) and the target sheave movement amount (target GRTO) is calculated (STEP 14).

Next, the solenoid duty value (DS1) at the next upshift is corrected to suppress the shift amount variation due to the upshift solenoid variation. Specifically, a corrected solenoid duty value (DS1) β (%) corresponding to the sheave movement amount of the difference L calculated in STEP 14 is calculated from FIG. 2 (STEP 16), and the duty value (DS1) at the next upshift is calculated. (STEP 18). Actually, β (%) increases to the duty value (DS1) at the previous upshift.

As mentioned above, although embodiment, its concept, and peripheral technology about the shift control apparatus in this invention were described, this invention is not limited to this, It deviates from the mind and teaching as described in a claim, a description, etc. It will be understood by those skilled in the art that other modifications and improvements can be obtained without departing from the scope.

Claims (2)

A shift control apparatus for a vehicle including a continuously variable transmission having a lock-up control mechanism,
Perform an upshift with lockup,
A speed change control apparatus, characterized in that a speed change command value is set to a predetermined value lower than a maximum command value of a target speed ratio for a predetermined time (X) including when the lockup clutch is engaged. Calculating a difference between a sheave movement amount at a predetermined time (Y) within the predetermined time (X) and a target sheave movement amount with respect to the upshift;
After completion of the upshift, a duty value correction corresponding to the difference is performed on the solenoid duty value known to the shift command value at the next upshift.
The speed change control device according to claim 1, wherein: