JP3967877B2 - Slip lockup control device for automatic transmission for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a slip lockup control device for an automatic transmission for a vehicle, and more particularly to a slip lockup control for controlling a difference in rotational speed between an input shaft and an output shaft of a torque converter.
[0002]
[Prior art]
Conventionally, in an automatic transmission for a vehicle having a lockup clutch that mechanically directly connects an input shaft and an output shaft of a torque converter, a rotational speed difference between the input shaft and the output shaft of the torque converter (hereinafter referred to as slip rotation). Slip lock-up control (half-clutch control) is known in which the engagement force of the lock-up clutch is controlled so that the speed (also referred to as speed) matches a target value.
[0003]
As an apparatus for performing the slip lock-up control, there has been one disclosed in Japanese Patent Application Laid-Open No. 11-082726.
This calculates a feedback command value based on a deviation between an actual slip rotation speed and a target slip rotation speed, converts the feedback command value into a target torque converter torque by a predetermined gain, and outputs the target torque converter torque. The engagement pressure command value of the lockup clutch is calculated from the engine output torque.
[0004]
[Problems to be solved by the invention]
In the above conventional slip lock-up control device, the gain is changed according to the turbine rotational speed (output shaft rotational speed of the torque converter), but the vehicle is in a coast state or a drive state even at the same turbine rotational speed. Depending on how the gain is required, the appropriate target torque converter torque for matching the slip rotation speed to the target cannot be set in both the coast state and the drive state, and the gain does not fit. In this state, the controllability is greatly impaired, and there is a possibility of generating a fastening shock or the like.
[0005]
The present invention has been made in view of the above problems, and is an automatic transmission for a vehicle that can set an appropriate target torque converter torque for making a slip rotation speed coincide with a target in both a coast state and a drive state. An object of the present invention is to provide a slip lockup control device for a machine.
[0006]
[Means for Solving the Problems]
Therefore, according to the first aspect of the present invention, the slip rotation speed that is the difference between the rotation speeds of the input shaft and the output shaft is detected, and the feedback command calculated based on the deviation between the detected slip rotation speed and the target slip rotation speed. A slip lockup control device for an automatic transmission for a vehicle configured to convert a value into a target torque converter torque based on a predetermined gain and to determine an engagement pressure command value for a lockup clutch based on the target torque converter torque In the above configuration, the gain is set smaller when the vehicle is in the driving state than when the vehicle is in the coasting state .
[0007]
According to such a configuration, when the vehicle is in the drive state, the gain is set smaller than that in the coast state, and the feedback command value is converted into the target torque converter torque with the gain . According to a second aspect of the present invention, the coast state / drive state is determined based on at least one of the throttle opening of the engine, the output torque of the engine, and the slip rotation speed.
[0008]
According to such a configuration, the opening degree of the throttle for adjusting the output torque of the engine, the output torque of the engine controlled by the throttle, and the slip rotation speed that is changed by reversing the driving side depending on whether the driving state or the coasting state is achieved. Based on this, the coast state / drive state is determined.
According to a third aspect of the present invention, an idle switch that is turned on when the throttle opening is equal to or less than a predetermined value is provided, and the coast state / drive state is discriminated based on ON / OFF of the idle switch.
[0009]
According to such a configuration, the idle switch is turned on when the throttle opening is equal to or less than a predetermined value, and is turned off when the opening exceeds the predetermined value. For example, the idle state of the idle switch is determined as the coast state. Then, the OFF state of the idle switch is determined as the drive state.
In the invention of claim 4, it is determined that the engine is in a coast state when the throttle opening of the engine is equal to or less than a predetermined opening, the throttle opening exceeds the predetermined opening, and the slip rotation speed is When it is less than the determination value, it is determined that the vehicle is in the coasting state. On the other hand, when the throttle opening exceeds the predetermined opening and the slip rotation speed is greater than the determination value, it is determined that the driving state is established. The configuration.
[0010]
According to such a configuration, if the throttle opening is equal to or less than the predetermined opening, it is determined that the coast is in the coasting state, but even if the throttle opening exceeds the predetermined opening, if the actual slip rotation speed is equal to or less than the determination value. It is determined that the vehicle is in the coasting state, and it is determined that the vehicle is in the driving state when the throttle opening exceeds a predetermined opening and the actual slip rotation speed is greater than the determination value.
[0011]
In the invention according to claim 5, as a table storing gains corresponding to the output shaft rotational speed of the torque converter, a table corresponding to the coast state and a table corresponding to the drive state are provided in advance, and the coast state / drive state The table to be referred to is selected based on the determination result.
According to such a configuration, one of the two tables is selected according to the determination result of the coast state / drive state, the gain corresponding to the output shaft rotation speed at that time is searched from the selected table, and the search is performed. The feedback command value is converted into the target torque converter torque using the gain.
[0012]
【The invention's effect】
According to the first aspect of the present invention, the gain used for converting the feedback command value into the target torque converter torque is smaller when the vehicle is in the driving state than in the coasting state. It is possible to respond to different gain requirements in the state and the drive state, and by this, the optimum target torque converter torque is set in both the coast state and the drive state, and a shock is generated in the slip lockup control. There is an effect that can be prevented.
[0013]
According to the second aspect of the present invention, there is an effect that the coast drive state of the vehicle can be accurately determined from the throttle opening of the engine, the output torque of the engine, and the slip rotation speed.
According to the third aspect of the invention, there is an effect that the coast state and the drive state can be easily distinguished using the idle switch.
[0014]
According to the fourth aspect of the present invention, since the coast state and the drive state are discriminated from both the throttle opening and the slip rotation speed, the gain can be switched more accurately.
According to the fifth aspect of the present invention, there is an effect that it is possible to easily cope with a request for a gain change according to a coast drive state while responding to a request for a gain change according to the output shaft rotation speed of the torque converter.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
FIG. 1 is a system configuration diagram of a vehicle automatic transmission according to an embodiment.
In FIG. 1, a gear type transmission 3 is coupled to an engine 1 via a torque converter 2. The transmission 3 may be a belt-type or toroidal-type continuously variable transmission (CVT).
[0016]
The torque converter 2 is provided with a lockup clutch 21 that mechanically directly connects the input shaft and the output shaft, and is engaged with the hydraulic pressure supplied to the release side of the lockup clutch 21 by the lockup hydraulic control valve 22. The hydraulic pressure supplied to the side is controlled.
The transmission control unit 31 that controls the lockup hydraulic control valve 22 includes a throttle sensor 13 that detects the opening TVO of the throttle valve 12 interposed in the intake pipe 11 of the engine 1, and the rotational speed Ne of the engine 1. The engine speed sensor 32 to detect, the turbine speed sensor 33 to detect the turbine speed ωtr of the torque converter 2, the vehicle speed sensor 34 to detect the vehicle running speed (vehicle speed) VSP, and the temperature of the automatic transmission fluid (ATF). Detection signals from an oil temperature sensor 35 that detects Tatf, an impeller rotation speed sensor 36 that detects an impeller rotation speed ωir of the torque converter 2, and the like are input, and the lockup hydraulic control valve 22 is controlled based on these detection signals. In addition, the various types of friction constituting the gear transmission 3 Controlling the gear valve for controlling the supply of hydraulic pressure for the engaging element.
[0017]
The throttle sensor 13 is provided with an idle switch 13a that is turned on when the throttle opening is equal to or less than a predetermined value (substantially fully closed).
The transmission control unit 31 controls the shift valve according to a preset shift schedule corresponding to the throttle opening TVO (accelerator opening) and the vehicle speed VSP, while the throttle opening TVO (accelerator opening) and In the slip lock-up control region set in advance according to the vehicle speed VSP, the lock-up hydraulic pressure control is performed so that the slip rotation speed that is the difference between the input shaft rotation speed and the output shaft rotation speed of the torque converter 2 becomes a target value. The valve 22 is controlled.
[0018]
The slip lock-up control by the transmission control unit 31 is performed by the arithmetic processing shown in the control block diagram of FIG.
In FIG. 2, the target slip rotation calculation unit 101 determines a target slip rotation speed Tslip based on the vehicle speed VSP, the throttle opening TVO, the gear ratio, and the oil temperature Tatf, and the target slip rotation Tslip is determined as the slip rotation deviation calculation unit 103. Output to.
[0019]
The actual slip rotation calculating unit 102 subtracts the turbine rotation speed ωtr corresponding to the output shaft rotation speed from the impeller rotation speed ωir corresponding to the input shaft rotation speed of the torque converter 2, thereby obtaining the actual slip rotation speed Slip of the torque converter 2. And the actual slip rotation speed Slip is output to the slip rotation deviation calculation unit 103.
The slip rotation deviation calculation unit 103 calculates a slip rotation deviation Eslip that is a deviation between the target slip rotation speed Tslip and the actual slip rotation speed Slip.
[0020]
Eslip = Tslip-Slip
The slip rotation command value calculation unit 104 eliminates the slip rotation deviation Eslip by using, for example, a known proportional (P) / integration (I) operation based on the slip rotation deviation Eslip, and converts the actual slip rotation speed Slip to the target slip rotation speed Tslip. A slip rotation command value (feedback command value) Scnv is calculated to match the above.
[0021]
Based on the slip rotation command value Scnv and the slip rotation gain Cg, the target converter torque calculation unit 105 is a torque converter that should be a target for achieving the slip rotation command value Scnv under the turbine rotation speed ωtr at that time. Torque Tcnv is calculated.
The gain Cg is set by a drive slip rotation gain calculation unit 106, a coast slip rotation gain calculation unit 107, a drive / coast determination unit 108, and a switching unit 109.
[0022]
Turbine rotational speed ωtr is input to the driving slip rotational gain calculator 106 and the coast slip rotational gain calculator 107, respectively, while the slip rotational gain calculators 106 and 107 are set in advance to the turbine rotational speed ωtr. A table storing corresponding slip rotation gains Cgd and Cgc is provided (see FIG. 3).
[0023]
Then, the slip rotation gain calculation units 106 and 107 search for slip rotation gains Cgd and Cgc corresponding to the inputted turbine rotation speed ωtr, and output the searched slip rotation gains Cgd and Cgc.
The slip rotation gain Cgd table provided in the drive slip rotation gain calculation unit 106 is adapted to convert the slip rotation command value Scnv into the target converter torque Tcnv in the drive state, while on the coast slip slip gain calculation. The table of the slip rotation gain Cgc provided in the section 107 is adapted to convert the slip rotation command value Scnv to the target converter torque Tcnv in the coast state, and is smaller as the turbine rotation speed ωtr is higher, as shown in FIG. The driving slip rotation gain Cgd is set to a value smaller than the coast slip rotation gain Cgc.
[0024]
The slip rotation gains Cgd and Cgc output from the drive slip rotation gain calculation unit 106 and the coast slip slip gain calculation unit 107 are input to the switching unit 109 and correspond to a selection command signal from the drive / coast determination unit 108. One of the slip rotation gains Cgd and Cgc is output to the target converter torque calculation unit 105 by the switching operation of the switching unit 109.
[0025]
The drive / coast determination unit 108 determines whether the vehicle is in a driving state or a coasting state. When the vehicle is in a driving state, the driving slip rotation gain Cgd is selected and output to the target converter torque calculation unit 105. As described above, the selection command signal is output to the switching unit 109. When the coasting state is in effect, the coasting slip rotation gain Cgc is selected and output to the target converter torque calculating unit 105 so that the switching unit 109 is selected. In response, a selection command signal is output.
[0026]
In the above description, the slip rotation gains Cgd and Cgc are respectively calculated and either one is selectively output based on the determination result of the drive / coast state. Based on this, either one of the slip rotation gain calculation units 106 and 107 may be operated.
The details of the drive / coast discrimination process are shown in the flowchart of FIG.
[0027]
In the flowchart of FIG. 4, in step S1, it is determined whether the idle switch 13a is on or off.
When the idle switch 13a is ON, the process proceeds to step S2, where it is determined that the coasting state is established. When the idle switch 13a is OFF, the process proceeds to step S3, where it is determined that the driving state is established.
[0028]
The drive / coast discrimination process can be performed by the process shown in the flowchart of FIG. 5 in place of the process shown in the flowchart of FIG.
In the flowchart of FIG. 5, in step S11, the engine output torque is estimated based on, for example, the throttle opening TVO and the engine rotation speed Ne. In step S12, whether or not the estimated engine output torque is equal to or less than a predetermined value. Is determined.
[0029]
If the engine output torque is equal to or less than the predetermined value, the process proceeds to step S13, where it is determined that the engine is in the coast state. If the engine output torque exceeds the predetermined value, the process proceeds to step S14, where the drive state is determined. .
Further, as shown in the flowchart of FIG. 6, the drive / coast discrimination process can be performed based on the idle switch 13a and the actual slip rotation speed Slip.
[0030]
In the flowchart of FIG. 6, in step S21, it is determined whether the idle switch 13a is ON or OFF. If the idle switch 13a is ON, the process proceeds to step S24 and is determined to be in the course state.
On the other hand, when the idle switch 13a is OFF, the process proceeds to step S22, and it is determined whether or not the actual slip rotation speed Slip is smaller than the first determination value KSLIP1.
[0031]
Here, when the actual slip rotation speed Slip is smaller than the first determination value KSLIP1, the process proceeds to step S24 and is determined to be in the course state.
When the actual slip rotation speed Slip is equal to or higher than the first determination value KSLIP1, the process proceeds to step S23.
In step S23, it is determined whether or not the actual slip rotation speed Slip is greater than a second determination value KSLIP2 that is greater than the first determination value KSLIP1.
[0032]
When the actual slip rotation speed Slip is larger than the second determination value KSLIP2, the process proceeds to step S25 and it is determined that the drive state is set.
On the other hand, when it is determined in step S23 that the actual slip rotation speed Slip is equal to or lower than the second determination value KSLIP2, that is, the actual slip rotation speed Slip is equal to or higher than the first determination value KSLIP1 and the second determination value. When the value is equal to or less than the value KSLIP2, the process proceeds to step S26 to determine that the state is intermediate between the coast state and the drive state.
[0033]
When the coasting / driving state is determined as described above, the slip rotation gain Cg is set based on the determination result. In the case of determining either the coasting state or the driving state, FIG. The gain Cg is set as shown in the flowchart.
In the flowchart of FIG. 7, in step S31, as shown in the flowchart of FIG. 4 or FIG. 5, the operation state at that time is discriminated as either a coast state or a drive state.
[0034]
In step S32, it is determined whether the determination result is the coast state or the drive state. If the determination result is the coast state, the process proceeds to step S33, and the coast slip rotation gain Cgc is output to the target converter torque calculation unit 105. If it is in the drive state, the process proceeds to step S 34, and the drive-time slip rotation gain Cgd is output to the target converter torque calculation unit 105.
[0035]
On the other hand, when it is determined according to the flowchart of FIG. 6 that the coast state, the drive state, or the intermediate state is set, the gain Cg is set as shown in the flowchart of FIG.
In the flowchart of FIG. 8, in step S41, as shown in the flowchart of FIG. 6, the operation state at that time is determined as one of a coast state, a drive state, and an intermediate state.
[0036]
In step S42, it is determined whether or not the determination result in step S41 is in an intermediate state. If it is determined in the intermediate state, the process proceeds to step S44, and the coast slip rotation gain Cgc is sent to the target converter torque calculation unit 105. Output.
If it is determined in step S42 that the state is not the intermediate state, the process proceeds to step S43, and it is determined whether or not the determination result in step S41 is the drive state.
[0037]
Here, when it is not determined that the vehicle is in the drive state, it is determined that the remaining coast state is not in either the intermediate state or the drive state. Therefore, the process proceeds to step S44, and the slip rotation during coasting is performed. The gain Cgc is output to the target converter torque calculator 105.
If it is determined in step S43 that the vehicle is in the drive state, the process proceeds to step S45, and the drive-time slip rotation gain Cgd is output to the target converter torque calculation unit 105.
[0038]
In the above description, the coast-time slip rotation gain Cgc is output to the target converter torque calculation unit 105 in the intermediate state. However, depending on the settings of the first and second determination values KSLIP1, KSLIP2, The driving slip rotation gain Cgd may be output in the state.
Further, when the vehicle is in the intermediate state, an intermediate value between the coast slip rotational gain Cgc and the drive slip rotational gain Cgd is output, or in the intermediate state when shifting from the coast to the drive, the coast slip rotational gain is obtained. The driving slip rotational gain Cgd may be gradually changed from Cgc, and the driving slip rotational gain Cgd may be gradually changed to the coast slip rotational gain Cgc in an intermediate state when the driving is shifted to the coast.
[0039]
The target converter torque calculation unit 105 calculates the target torque converter torque Tcnv from the slip rotation gain Cg and the slip rotation command value Scnv set as described above.
The engine output torque estimating unit 110 obtains an estimated value Te of the engine output torque from the engine speed Ne and the throttle opening TVO, and outputs the estimated value Te.
[0040]
In the estimation of the engine output torque based on the engine rotational speed Ne and the throttle opening TVO, the delay is made to cope with the response delay of the actual engine output torque with respect to changes in the engine rotational speed Ne and / or the throttle opening TVO. It is preferable to perform a filtering process corresponding to the characteristics.
The target lockup clutch engagement capacity calculation unit 111 subtracts the target converter torque Tcnv from the engine output torque Te to obtain the target lockup clutch engagement capacity Tlu.
[0041]
Tlu = Te-Tcnv
The lockup clutch engagement pressure command value calculation unit 112 calculates a lockup clutch engagement pressure command value Plu for achieving the target lockup clutch engagement capacity Tlu.
The drive signal calculation unit 113 determines a drive signal Dlu for setting the actual lockup clutch engagement pressure to the lockup clutch engagement pressure command value Plu, and outputs this to the lockup hydraulic control valve 22.
[0042]
In the above embodiment, the table for storing the slip rotation gain Cgc at the coast and the table for storing the slip rotation gain Cgd at the time of driving are separately provided. Only a table that stores one of the rotation gains Cgd may be provided, and the rotation gain retrieved from the table may be corrected and used with a correction value stored in advance when the table is in an incompatible operating state.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram of an automatic transmission according to an embodiment.
FIG. 2 is a functional block diagram of slip lock-up control in the embodiment.
FIG. 3 is a diagram showing a characteristic of slip rotation gain in the embodiment.
FIG. 4 is a flowchart showing a state of drive / coast state determination based on an idle switch.
FIG. 5 is a flowchart showing a state of drive / coast state determination based on engine output torque.
FIG. 6 is a flowchart showing a state of drive / coast state determination based on an idle switch and a slip rotation speed.
FIG. 7 is a flowchart showing setting of a slip rotation gain based on a determination result of a drive / coast state.
FIG. 8 is a flowchart showing setting of a slip rotation gain based on a determination result of a drive / coast / intermediate state.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Torque converter 3 ... Gear-type transmission 12 ... Throttle valve 13 ... Throttle sensor 13a ... Idle switch 21 ... Lock-up clutch 22 ... Lock-up hydraulic control valve 31 ... Transmission control unit 32 ... Engine rotational speed sensor 33 ... Turbine rotation speed sensor 34 ... Vehicle speed sensor 35 ... Oil temperature sensor 36 ... Impeller rotation speed sensor

Claims (5)

A lockup clutch that mechanically directly connects an input shaft and an output shaft of a torque converter interposed between an engine and a transmission, and a slip rotational speed that is a rotational speed difference between the input shaft and the output shaft; Detecting and converting a feedback command value calculated based on a deviation between the detected slip rotation speed and the target slip rotation speed into a target torque converter torque based on a predetermined gain, and based on the target torque converter torque In the slip lockup control device for an automatic transmission for a vehicle configured to determine the engagement pressure command value of the lockup clutch,
A slip lock-up control device for an automatic transmission for a vehicle, wherein the gain is made smaller when the vehicle is in a driving state than when the vehicle is in a coasting state . 2. The vehicle automatic according to claim 1, wherein the coast state / drive state is determined based on at least one of the throttle opening of the engine, the output torque of the engine, and the slip rotation speed. Slip lockup control device for transmission. The idle state switch which is turned on when the throttle opening is equal to or less than a predetermined value is provided, and the coast state / drive state is discriminated based on ON / OFF of the idle switch. A slip lock-up control device for an automatic transmission for a vehicle. When it is determined that the engine is in a coast state when the throttle opening of the engine is less than or equal to a predetermined opening, and when the throttle opening exceeds the predetermined opening and the slip rotation speed is less than or equal to a determination value 2. While determining that the vehicle is in a coasting state, it is determined that the vehicle is in a driving state when the throttle opening exceeds the predetermined opening and the slip rotation speed is greater than the determination value. 3. A slip lock-up control device for an automatic transmission for vehicles according to 2. As a table storing the gain corresponding to the output shaft rotation speed of the torque converter, a table corresponding to the coast state and a table corresponding to the drive state are provided in advance, and based on the determination result of the coast state / drive state The slip lock-up control device for an automatic transmission for a vehicle according to any one of claims 1 to 4, wherein the table to be referred to is selected.

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