JP2903456B2 - Lockup control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lock-up control device for an automatic transmission for promoting warm-up.

[0002]

2. Description of the Related Art In an automatic transmission, in order to improve fuel efficiency by improving transmission efficiency, a torque converter requires a torque converter between input and output elements in a state where a torque increasing function and a torque fluctuation absorbing function are unnecessary. There is a tendency to switch to a lockup type that can be brought into a directly connected lockup state.

[0003] Lock-up control of this type of torque converter for promoting warm-up is conventionally performed by using an automatic transmission described in, for example, "NISSAN RE4R01A type full-range electronically controlled automatic transmission maintenance manual" issued by the present applicant. Until the hydraulic oil temperature of the automatic transmission reaches the set value, lock-up of the torque converter is prohibited and the torque converter is maintained in a converter state in which the direct connection between the input and output elements is broken. It is customary to promote warm-up by agitating the working oil by the relative rotation of the output element.

[0004]

[SUMMARY OF THE INVENTION However, such a conventional lock-up control technology for promotion of warming, monitors transmission working oil temperature Ta as shown in FIG. 5 (a), the engine start instant t ₁ , The transmission operating oil temperature Ta is equal to the set value Ta.
over during Delta] t _a to reach s, since it inhibits the lockup of the torque converter, it has arisen the following problems.

More specifically, referring to the engine cooling water temperature Te also illustrated in FIG. 5 (a), if the lock-up of the torque converter is performed in a low temperature range lower than a certain engine cooling water temperature set value Tes, the unburned unburned exhaust gas Although the harmful substances increase and cause a serious problem in the exhaust gas countermeasures, it must be avoided, but the engine cooling water temperature Te is set to the set value Tes.
In the high temperature range described above, it is preferable not to prohibit lock-up of the torque converter in terms of fuel efficiency. However, in the conventional lock-up control for promoting warm-up, the transmission operating oil temperature Ta
Lock-up of the torque converter is prohibited until the vehicle speed V reaches the set value Tas. Therefore, the lock-up of the torque converter performed on the condition that the vehicle speed V becomes equal to or higher than the lock-up vehicle speed _VL is performed during the period Δt _b. As a result, the lock-up period is shortened accordingly, which hinders improvement in fuel efficiency.

FIG. 5 (a) shows a time-dependent change characteristic when the vehicle is driven from the time when the engine is started and before the completion of warm-up, and the change over time as shown in FIG. 5 (b) is shown. When the vehicle is driven after a short period of warm-up operation after the engine starts, the lock-up inhibition period Δ
Since t _a becomes longer, the period Δt _b during which the torque converter is prohibited is longer even though it is better to lock up the torque converter, and the above problem becomes more remarkable.

However, as shown in FIG. 5 (c), when the set value Tas of the transmission operating oil temperature is lowered, particularly in FIG.
As in the case of (a), when the vehicle is driven from before the warm-up is completed at the same time as the start of the engine, the lock-up prohibition period Δt _a becomes extremely short, and the lock-up should not yet be performed in view of the exhaust gas countermeasures described above. An operation that must be avoided, such as locking up the torque converter during the period Δt _C , is performed.

In order to solve the above-mentioned problem, as is apparent from the above, the engine cooling water temperature Te is monitored,
It is conceivable that a period until this reaches the set value Tes is a period during which lockup of the torque converter should be prohibited to promote warm-up. In this case, the engine cooling water temperature Te is originally used for controlling the automatic transmission. Is not used, a signal line for taking in the detection signal of the engine cooling water temperature Te is newly required, so that the disadvantage in cost cannot be avoided.

The present invention, although there are some differences depending on the initial cooling water temperature Te _1, Te ₂ and operating conditions at the start of the engine, as shown in FIG. 4, an engine coolant temperature Te, the engine rotation from the start There is a substantially constant relationship between the integral value of the number {Ne} and the integral value of the engine speed Σ
The engine coolant temperature Te can be detected from Ne,
Based on the fact that after the integral value ΣNe of the engine speed reaches a set value K corresponding to the lower limit value Tes of the engine cooling water temperature range in which lockup is possible, it can be determined that lockup is possible, Since the signal line of the engine speed Ne originally exists in the control system of the automatic transmission and the addition of the signal line is unnecessary, the engine speed integral value from the start is calculated, and this is calculated as the above set value. It is an object of the present invention to eliminate all the above-mentioned various problems by adopting a configuration in which the lock-up prohibition period is set until the time when the lock-up is stopped.

In the case where the engine is restarted immediately after the vehicle is stopped from the running state and the vehicle is started, for example, the engine cooling water temperature is already considerably high. Therefore, the integral value of the engine speed indicating the engine speed is the engine cooling water temperature. If lockup is prohibited until this integral value reaches a set value without accurately responding to the above, the prohibition period is too long and the fuel efficiency improvement effect due to lockup is diminished.

Therefore, the present invention also stops the lock-up inhibiting action when the elapsed time from when the start of the engine is detected reaches a set time for each hydraulic oil temperature of the automatic transmission. It is an object of the present invention to solve the above-mentioned problem by adopting the configuration described above.

[0012]

To achieve these objects, the lock-up control device for an automatic transmission according to the first invention, as schematically shown in FIG. In a vehicle equipped with an automatic transmission that receives a rotation and changes the rotation and outputs the rotation, an engine start detection unit that detects the start of the engine and a rotation speed detection unit that detects a rotation speed that indicates the rotation speed of the engine In response to signals from these means, from the time when the start of the engine is detected, to the number of revolutions integrating means for integrating the number of revolutions representing the number of revolutions of the engine, and A lock-up prohibiting unit for prohibiting lock-up of the torque converter and an elapsed time from when the engine start detecting unit detects the start of the engine. Time means, temperature detection means for detecting a temperature representing the operating oil temperature of the automatic transmission at the time of detection of the engine start, and time elapsed from when the start of the engine is detected in response to a signal from these means. A lock-up prohibition suspending means for suspending a lock-up prohibiting action by the lock-up prohibiting means when a set time for each temperature representing a hydraulic oil temperature of the automatic transmission is reached. It is.

According to a second aspect of the present invention, in the first aspect, the engine speed itself is used as the engine speed representing the engine speed.

According to a third aspect of the present invention, in the first aspect, the vehicle speed is used as the number of revolutions indicating the number of revolutions of the engine.

[0015]

In the first aspect of the invention, the torque converter transmits the engine rotation to the automatic transmission in a lockup state in which the input / output elements are directly connected or in a converter state in which the input / output elements are disconnected. Ri by the outputting by shifting the rotation, drive the vehicle.

By the way, when the engine start detecting means detects the start of the engine, from this time, the rotational speed integrating means integrates the rotational speed representing the engine rotational speed detected by the rotational speed detecting means. Lock-up prohibition means prohibits the lock-up of the torque converter and promotes warm-up until the integrated value reaches a set value.

Accordingly, the engine cooling water temperature is indirectly detected by the above-mentioned integral value of the number of revolutions, and the lock-up prohibition period for promoting the warm-up operation is determined based on the detected temperature. The torque converter should not be locked up, it can be matched to the engine coolant temperature range, and in any operating condition, the torque converter may be locked up during the period when the Despite the fact that the lockup should be performed without causing any problem, it is possible to eliminate the adverse effects such as the fact that the torque converter is not locked up for a long period of time and the fuel efficiency improvement effect is reduced. Moreover,
Since this effect is achieved by indirect monitoring of the engine cooling water temperature, the effect can be achieved without adding a signal line for the engine cooling water temperature, and there is no disadvantage in cost.

Further, in addition to the above functions, the following functions are obtained. That is, the elapsed time from when the engine start detecting means detects the start of the engine is measured by the timer means, and the temperature indicating the operating oil temperature of the automatic transmission at the time of detecting the engine start is detected by the temperature detecting means. In response to a signal from these means, the lock-up prohibition suspending means detects when the elapsed time from when the start of the engine is detected reaches a set time for each temperature representing the operating oil temperature of the automatic transmission. The lock-up prohibiting action by the lock-up prohibiting means is stopped.

Therefore, when the engine is restarted immediately after the vehicle is stopped from the running state and the vehicle is started, for example, the engine cooling water temperature is already sufficiently high. If the lockup is prohibited until the integral value reaches the set value without accurately responding to the water temperature, the prohibition period is too long and the fuel efficiency improvement effect by the lockup is diminished. When the time elapsed since the detection is reached reaches the set time for each hydraulic oil temperature of the automatic transmission, the lock-up prohibiting action is stopped.After stopping the vehicle from the running state, the engine is restarted. When starting, the lock-up prohibition action is interrupted before the above-mentioned integral value reaches the set value. That such fuel efficiency fades, it is possible to solve the above problems.

It should be noted that it is preferable to use the engine speed itself as in the second invention in order to further ensure the above-mentioned effects, but it is preferable to use the engine speed itself as the engine speed indicating the engine speed. The vehicle speed can be used as in the third invention. This vehicle speed is indispensable for speed change control in any automatic transmission, and is already existing and is advantageous in that versatility is enhanced. However, since the vehicle speed is of course not generated unless the vehicle runs, it goes without saying that the above-described operational effects can be obtained only when the vehicle runs at the same time as the start of the engine.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 shows a lock-up control device for an automatic transmission according to an embodiment of the present invention.
Denotes an engine, and 2 denotes an automatic transmission. The automatic transmission 2 receives the power of the engine 1 via the torque converter 3,
It is assumed that the input rotation is shifted at a gear ratio according to the selected shift speed and transmitted to the output shaft 4.

Here, the automatic transmission 2 turns on and off the shift solenoids 6 and 7 in the control valve 5.
The gear ratio is determined by the combination of the torque converter 3 and the torque converter 3 is turned on or off by the lock-up solenoid 8 in the control valve 5 in a lock-up state in which the input / output elements are directly connected or in a converter state in which the direct connection is released. Power transmission shall be performed.

ON / OFF of shift solenoids 6 and 7;
The ON / OFF of the lock-up solenoid 8 is controlled by a controller 9. The controller 9 receives a signal from an engine rotation sensor 10 for detecting the rotation speed Ne of the engine 1 and a throttle opening TH of the engine 1. A signal from the throttle opening sensor 11 to be detected,
A signal from a vehicle speed sensor 12 for detecting a vehicle speed V from the rotation speed of the transmission output shaft 4 and a hydraulic oil temperature Ta of the automatic transmission 2
Are respectively input from the oil temperature sensors 13 for detecting the pressure.

Although not shown, the controller 9 performs the following shift control and normal lock-up control by well-known calculations based on these input information. That is, first, the shift control will be described. The throttle opening TH and the vehicle speed V
The optimum gear position for the current operation state is obtained by, for example, a table look-up method, and the shift solenoids 6 and 7 are turned ON and OFF to perform a predetermined gear shift so that the optimum gear position is selected. Next, the normal lock-up control will be described. In the lock-up region where the torque increasing function and the torque fluctuation absorbing function by the torque converter 3 are not necessary based on the throttle opening TH and the vehicle speed V for each specific gear or each gear. It is determined whether the motor is operating in the converter region where these functions are required or in the converter region where these functions are required.
Into a lockup state where the input and output elements are directly connected,
Lock-up solenoid 8 is OFF in converter area
Then, the torque converter 3 is brought into a converter state in which the direct connection is released.

The controller 9 performs a lock-up control for promoting warm-up, in addition to the normal lock-up control, based on the control program shown in FIG. 3 as follows. The control program shown in FIG. 3 is started in step 21 when the ignition switch is turned on to start the engine, and thereafter is repeatedly executed in step 22 by a periodic interruption every 0.1 seconds, for example.

At the start of the program in step 21, the following initial settings are made. This start determination flag ... OFF Engine speed Ne ... 0 rpm Previous start determination flag ... OFF Lockup prohibition flag ... ON Start timer ······· 油 Hydraulic oil temperature for timer setting ······ − Engine speed integral ΣNe ··· 0

In step 23, the engine speed Ne is read. In step 24, whether the engine has been started or not has been checked based on whether or not the previous start determination flag is ON. If the engine has not been started, it is determined at step 25 whether or not the engine has been started based on whether or not the engine speed Ne is, for example, 800 rpm or more. At the time of starting at which Ne ≧ 800 rpm, at step 26, the present start determination flag is turned ON to indicate this.

In step 24, if it is determined that the engine has been started, then in step 27, it is checked whether or not the engine should be stopped by checking if the engine speed Ne is, for example, 200 rpm or less. Is
In step 28, the present start determination flag is turned off, in step 29, the lock-up prohibition flag is turned on, and in step 30, a timer described later is reset.

[0029] At step 31, the previous engine start determination flag is OFF, and the current whether or not the engine start determination flag is ON, the checks whether reaches the engine start instant t ₁ of FIG. Steps 32 to 35 are executed only once at the moment of starting the engine, and the transmission operating oil temperature Ta at this instant is read, and the operating oil temperature Ta is measured by a timer for measuring the elapsed time from the instant. To the timer setting oil temperature used for setting the time, and for the next control, the current start determination flag is set to the previous start determination flag. Set the time according to the temperature.

Here, the time corresponding to the timer setting oil temperature is set as follows. That is,
As described above, in the case where the engine is immediately restarted and started after the vehicle is stopped from the running state, the engine cooling water temperature is already considerably high, and therefore the integral value of the engine speed indicating the engine speed is the engine cooling water temperature. If lock-up is prohibited until this integral value reaches the set value, the lock-up period is too long and the fuel efficiency improvement effect of lock-up is diminished. The prohibition period is not determined by the integral value of the engine speed that indicates the engine speed, and in order to shorten the prohibition period, the time corresponding to the timer setting oil temperature is set to be higher as the setting oil temperature is higher. It shall be set short.

In step 36, the time is set as described above. In step 37, whether the timer decremented by one step (0.1 second) is 0 or not, the set time of the timer has elapsed from the moment when the engine is started. Check whether or not. As is apparent from the above description, except for the case where the engine is immediately restarted and the vehicle is started after the vehicle is stopped from the traveling state, the control time is set to a sufficiently long time. Follow, Step 3
In step 8, an integral value ΣNe of the engine speed Ne from the moment of engine start is calculated, and in step 39, the integral value ΣNe
Is determined to be greater than or equal to the set value K described above with reference to FIG.

While the integral value ΣNe of the engine speed Ne is less than the set value K, step 40 is skipped and the lock-up prohibition flag is turned on in step 21 or 29.
In this state, lock-up is prohibited as described later. Integral value of engine speed Ne ΣN
When e becomes equal to or greater than the set value K, step 40 is executed to turn off the lock-up prohibition flag, thereby releasing the lock-up prohibition.

If it is determined in step 36 that the set time of the timer has elapsed from the moment when the engine is started, step 40 is executed even before the integration value ΣNe ≧ K is confirmed in step 39, and lockup is prohibited. Flags OF
F, thereby releasing the lock-up prohibition.

In step 41, the lock-up prohibition flag is checked. In the lock-up prohibition releasing state in which the lock-up prohibition flag is turned off, the normal lock-up control and the shift control described above are executed in step 42, and the lock-up prohibition flag is turned on. In the lock-up prohibition state, the lock-up is prohibited in step 43, and only the normal shift control described above is executed.

According to the above control, the operation illustrated in FIG. 5D occurs. That is, from the instant t ₁ when the engine is started, an integral value ΣNe of the engine speed is obtained,
Until instant t ₂ this is a set value K, the torque converter lockup is prohibited, for performing power transmission by the relative rotation between the torque converter input and output elements by the prohibition of the automatic transmission by the relative rotation Stir hydraulic oil to promote warm-up. The instant t ₂ after the integrated value ΣNe of the engine speed reaches the set value K, the prohibition of the lock-up is released, it is possible to lock-up control torque converter as usual.

By the way, the integral value ΣNe engine speed from engine start instant t ₁ is represents a generally engine coolant temperature Te as described above per 4, also setting value K
Is determined in accordance with the lower limit value Tes of the engine cooling water temperature range, which does not cause a problem in the exhaust gas countermeasure even when the torque converter locks up, so that the moment the engine cooling water temperature Te reaches the lower limit value Tes, slower than, but it is possible to release the prohibition of only near instant t ₂ in the lock-up can be to this. Therefore, in any operation state, it is possible to prevent the torque converter from being locked up during the period of Te <Tes in which the torque converter should not be locked up for the exhaust gas countermeasure. The period Δt _b during which the torque converter is not locked up during the period of ≧ Tes can be minimized, and the effect of improving fuel efficiency by locking up the torque converter can be enhanced.

The following operations and effects can be obtained by the processing of steps 32 to 36 and 40. That is, when the engine is restarted immediately after the vehicle is stopped from the running state and the vehicle is started, for example, the engine cooling water temperature is already considerably high.
If the lockup is prohibited by the above control until the integrated value reaches the set value K, the prohibition period is too long, and the engine cooling may be locked up due to exhaust measures. The period Δt _b during which the lock-up is prohibited in spite of the water temperature range is greatly lengthened, and the effect of the lock-up to improve the fuel efficiency is diminished. However, according to the processes of steps 32 to 36 and 40, the lockup prohibition control is forcibly performed by the timer management when the time determined according to the operating oil temperature at the time of engine start has elapsed from the moment of engine start. Since the lockup prohibition period is shortened by terminating the lockup, the problem at the time of the restart can be eliminated.

In the above-described example, the engine speed itself is integrated and the integrated value is used for determining the lock-up inhibition period. However, the integrated value may be used instead of the vehicle speed. However, in this case, since the vehicle speed does not occur unless the vehicle travels, it is needless to say that the same operation and effect as in the above embodiment cannot be obtained unless the vehicle travels at the same time as the engine start.

Further, in the above-described example, the time set in the timer is determined by the automatic transmission operating oil temperature Ta at the time of starting the engine, but may be determined according to the outside air temperature.

[0040]

Thus, the lock-up control device according to the first aspect of the present invention integrates the rotation speed representing the engine rotation speed from the time of starting the engine, and this integrated value is set to the set value from the moment of starting the engine. Until the lockup of the torque converter is prohibited for promoting warm-up operation, the engine cooling water temperature is indirectly detected by the above integrated value, and based on this, the The lock-up prohibition period is determined, and this period can be accurately matched to the engine cooling water temperature range where the torque converter should not be locked up for exhaust measures. The torque converter is locked up during the period when it should not be locked up, or the torque converter is locked up Motor fuel consumption improvement effect fades without being locked up for a long period of time, it is possible to eliminate the adverse effect like.

Further, this operation and effect can be achieved without adding a signal line for the engine cooling water temperature, and there is no disadvantage in cost.

In addition, the first invention measures the elapsed time from the start of the engine, and when the elapsed time reaches a set time for each temperature indicating the hydraulic oil temperature of the automatic transmission at the start of the engine, the lock is set. Since the operation of prohibiting the up is stopped, the following operation and effect can be obtained in addition to the above operation.

In other words, in the case where the engine is immediately restarted and started after stopping from the running state, the lock-up prohibition operation can be interrupted before the above-mentioned integrated value reaches the set value. It is possible to solve a problem peculiar to the restart, that is, a problem that the lock-up prohibition period is too long and the fuel efficiency improvement effect by the lock-up is reduced.

In the case where the engine speed itself is used as the engine speed representing the engine speed as in the second aspect of the present invention, the above control and operation and effect are more accurate.

Further, as in the third aspect of the present invention, the vehicle speed may be used as the rotation speed representing the engine rotation speed. This vehicle speed is an essential signal for speed change control in any automatic transmission, and has an advantage of high versatility since it is always present. However, since the vehicle speed is of course not generated unless the vehicle runs, it goes without saying that the above-described operational effects can be obtained only when the vehicle runs at the same time as the start of the engine.

[Brief description of the drawings]

1A is a conceptual diagram showing a lock-up control device for an automatic transmission, and FIG. 1B is a conceptual diagram showing a lock-up control device for an automatic transmission according to a first invention.

FIG. 2 is a system diagram showing an embodiment of the lock-up control device of the present invention.

FIG. 3 is a flowchart showing a lock-up control program for promoting warm-up executed by a controller in the example.

FIG. 4 is a diagram illustrating a relationship between an engine cooling water temperature and an engine speed;

FIG. 5 (a) shows a lock-up prohibition period when a vehicle equipped with a conventional lock-up control device is run at the same time as the start of the engine. (B) shows a lock-up prohibition period when a vehicle equipped with a conventional lock-up control device is driven after a warm-up operation. (C) is a lock-up prohibition period when the vehicle equipped with the conventional lock-up control device is run under the same conditions as (a) by lowering the set value of the transmission operating oil temperature. A time chart showing the relationship between the engine cooling water temperature, the transmission operating oil temperature, and the vehicle speed, and (d) shows the lock-up prohibition period by the lock-up control device shown in FIGS. A cooling water temperature, a time chart shown with the relationship between the vehicle speed.

[Explanation of symbols]

 Reference Signs List 1 engine 2 automatic transmission 3 torque converter 5 control valve 6 shift solenoid 7 shift solenoid 8 lock-up solenoid 9 controller 10 engine rotation sensor 11 throttle opening sensor 12 vehicle speed sensor 13 oil temperature sensor

Claims (3)

(57) [Claims] 1. A vehicle equipped with an automatic transmission that receives the rotation of an engine via a torque converter that can be locked up, and that outputs the rotation after shifting the rotation, wherein engine start detection means for detecting the start of the engine; Rotation speed detection means for detecting a rotation speed representing the rotation speed of the engine; and a rotation speed for integrating the rotation speed representing the engine rotation speed from the time when the start of the engine is detected in response to signals from these means. Integrating means; lock-up prohibiting means for prohibiting lock-up of the torque converter until the integrated value of the means reaches a set value; and measuring an elapsed time from when the engine start detecting means detects the start of the engine. Time detecting means for detecting the temperature of the operating oil of the automatic transmission at the time of detecting the start of the engine; When the elapsed time from when the start of the engine is detected in response to these signals reaches a set time for each temperature indicating the hydraulic oil temperature of the automatic transmission, the lock-up prohibiting means inhibits lock-up. A lock-up control device for an automatic transmission, comprising: lock-up prohibition suspending means for suspending operation. 2. The lock-up control device for an automatic transmission according to claim 1, wherein the rotation speed is the engine rotation speed itself. 3. The lockup control device for an automatic transmission according to claim 1, wherein the rotation speed is a vehicle speed.