JP2006002910A - Lock-up clutch fastening force control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lock-up clutch fastening force control device for carrying out pressure rise following a target slip rotating speed during open control. <P>SOLUTION: A slip rotating speed deviation ERRslp as a deviation between the target slip rotating speed Tslp and an actual slip rotating speed Nslp is calculated during open control, a basic pressure rise variation ΔPLU is corrected in accordance with the slip rotating speed deviation ERRslp by a pressure rise variation correcting coefficient K, and pressure rise is carried out using a pressure rise variation corrected value ΔPLUadj. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an engagement force control device for a lock-up clutch, and more particularly to open loop control.

  The lock-up control device for the torque converter inserted in the driving force transmission system of the automatic transmission including the continuously variable transmission is designed to increase the torque and / or the transmission shock in order to reduce the deterioration of the fuel consumption caused by the slip of the torque converter. In the operation region where the absorption function is not required, the input / output elements of the torque converter are directly connected using a lock-up clutch. This is called the lock-up mode. In addition to this, the converter mode that completely releases the input and output elements and transmits torque via the fluid, and the slip that makes the lock-up clutch semi-engaged and maintains the predetermined slip state. There are three modes, which are switched according to the driving state of the vehicle. This mode switching is performed by changing the lockup differential pressure, and the converter mode is set for the minimum pressure and the lockup mode is set for the maximum pressure.

  Among these, when switching from the converter mode to the lockup mode, or when switching from the converter mode to the slip mode, the pressure is increased by the open control up to the predetermined lockup differential pressure, and then switched to the slip control, and the lockup mode smoothly. The predetermined slip mode is maintained by shifting and continuing the slip control.

When switching from the converter mode to the lockup mode or slip mode, the boost pressure is set according to the amount of change in the primary rotation speed by open control, and the slip rotation falls below the set rotation. Japanese Patent Application Laid-Open No. H10-228707 discloses a transition to slip control when the condition is satisfied.
JP 2004-138150 A

  However, in the above-described invention, the open control performs a pressure increasing operation using a preset pressure increasing amount (basic fastening force increase amount), for example, a pressure increasing amount corresponding to a change amount of the throttle opening or the primary rotation speed. Is set, excessive boosting or insufficient boosting occurs due to variations in the hydraulic characteristics of the torque converter and differences in operation.

  For this reason, it is conceivable to adjust the pressure increase amount by feedback control immediately after the start of the open control. However, since the lockup clutch operates by the action of the hydraulic circuit, the response delay of the lockup clutch immediately after the pressure increase starts, that is, the engagement pressure command value There is a problem that the feedback control reacts excessively with respect to the slip rotation speed deviation caused by the delay of the actual capacity of the lock-up clutch with respect to the pressure increase, resulting in excessive pressure increase.

  The present invention has been invented to solve such problems, and an object thereof is to prevent a shortage of the boosting amount or suppress an excessive boosting amount and perform boosting that follows the target slip rotation speed.

  In the present invention, a torque converter that transmits the power of the prime mover and has a lock-up clutch, an open control means that controls the engagement state of the lock-up clutch by open loop control based on the driving state of the vehicle, and the turbine rotation of the torque converter Turbine rotational speed detecting means for detecting the speed, impeller rotational speed detecting means for detecting the impeller rotational speed of the torque converter, slip rotational speed detecting means for calculating the actual slip rotational speed based on the turbine rotation and the impeller rotational speed, Target slip rotation speed calculating means for calculating the target slip rotation speed during open loop control, slip rotation speed deviation calculating means for calculating the slip rotation speed deviation between the target slip rotation speed and the actual slip rotation speed, and slip rotation speed deviation Based on said lockup Comprising a fastening force correcting value calculating means for calculating a correction value for correcting the basic engagement force increasing amounts of the latch. In the open loop control, the fastening force of the lockup clutch is increased by the correction value.

  According to the present invention, when the actual slip rotation speed greatly deviates from the target slip rotation speed in the open control, the engagement force is increased by correcting the engagement force (the increase amount of the engagement hydraulic pressure), thereby preventing an insufficient increase in the increase amount. Further, it is possible to suppress the excessive pressure increase amount and increase the fastening force following the target slip rotation speed.

  The configuration of the embodiment of the present invention will be described using the system configuration schematic diagram of FIG. In this embodiment, a torque converter 1 that transmits an output from an engine (motor) (not shown) to a transmission, a lockup clutch 2 that directly connects an input element and an output element of the torque converter 1, and engagement of the lockup clutch 2 A lockup control valve 3 for controlling the force and a controller 5 for outputting a signal of the fastening force of the lockup clutch 2 to the lockup control valve 3 are provided.

  The lockup clutch 2 responds to a differential pressure PA-PR between the torque converter apply pressure PA and the torque converter release pressure PR on both sides thereof, and the lockup clutch 2 is released when the release pressure PR is higher than the apply pressure PA. When the release pressure PR becomes lower than the apply pressure PA without directly connecting the torque converter input / output elements, the lockup clutch 2 is fastened and directly connected between the torque converter input / output elements. The fastening force of the lock-up clutch 2, that is, the lock-up capacity, is determined by the differential pressure PA-PR, and the greater the differential pressure, the greater the fastening force of the lock-up clutch 2 increases the lock-up capacity. Increase.

  The differential pressure PA-PR is controlled by a well-known lockup control valve 3, and the apply pressure PA and the release pressure PR are applied to the lockup control valve 3 so as to face each other, and the spring 3 a in the same direction as the apply pressure PA. The spring force is applied in the same direction as the release pressure PR, and at the same time, the signal pressure PS is applied in the same direction as the release pressure PR. The lockup control valve 3 determines the differential pressure PA-PR so that the forces generated by these components are balanced. Here, the signal pressure PS is generated by the lockup solenoid 4 according to the lockup duty D using the pump pressure PP as the original pressure, and the controller 5 controls the differential pressure PA-PR through the lockup solenoid 4.

  The controller 5 is a signal indicating the running state of the vehicle and the driving situation of the driver, for example, a signal from the output shaft rotation sensor 9 that is disposed in the automatic transmission and detects the vehicle speed (or vehicle speed equivalent value), the turbine runner rotation speed. Impeller rotational speed sensor (detecting vibration from turbine rotational speed sensor (turbine rotational speed detecting means) 8 for detecting (input shaft rotational speed or primary rotational speed), input rotational speed (or engine rotational speed) to torque converter A signal from the impeller rotational speed detection means 7, a signal from the hydraulic pressure sensor 11, a signal from the throttle opening sensor 10 for detecting the throttle opening (or the accelerator pedal operation amount), etc. are input, and lock-up fastening is performed based on the signals. Control calculations such as and release. The controller 5 determines the drive duty D of the lockup solenoid 4 based on the control calculation result and corrects the lockup duty D according to the power supply voltage signal 6.

With the above configuration, the lockup clutch 2 can be set to the converter mode, the slip mode, and the lockup mode.
Next, operation control of the lockup clutch 2 performed by the controller 5 will be described with reference to the flowchart of FIG. This control is performed every 20 ms, for example.

  In step S101, the vehicle speed sensor (not shown) detects the vehicle speed and the throttle opening degree by the throttle opening sensor 10, and the control performed by the lockup clutch 2 is determined from the map of FIG. 3 based on the speed and the throttle opening degree. . FIG. 3 is a map showing the control method of the vehicle speed, the throttle opening, and the lockup clutch 2. When the vehicle speed is smaller than the predetermined value V1, the lockup clutch 2 is controlled by the converter, the vehicle speed is larger than the predetermined value V1, and When the throttle opening is smaller than the predetermined value TVO1, slip control is performed. When the vehicle speed is larger than the predetermined value V2, or when the throttle opening is larger than the predetermined value TVO1, lockup control is performed. When the control of the lockup clutch 2 is the slip control, the process proceeds to step S104, and otherwise, the process proceeds to step S102 for the converter control and the lockup control. Note that conditions for determining converter control, slip control, and lockup control (boundaries of each control region) are set in advance.

  In step S102, if the result determined in step S101 is lock-up control, the process proceeds to step S103, and if it is converter control, the process proceeds to step S114.

  In step S103, it is determined whether or not the lockup control is completed, that is, whether or not the differential pressure between the apply pressure PA and the release pressure PR is a differential pressure command value necessary for engaging the lockup clutch 2 with the torque converter 1. If the differential pressure is the differential pressure command value, the lockup control has been completed, so the process proceeds to step S113. If the differential pressure is smaller than the differential pressure command value, the lockup control is completed. If not, the process proceeds to step S104.

  If it is determined in step S101 that the slip control has been performed, or if it is determined in step S103 that the lockup control has not been completed, it is determined in step S104 whether the previous control of the lockup clutch 2 was converter control. If the previous control of the lock-up clutch 2 is converter control, the process proceeds to step S105, and if not, the process proceeds to step S107.

  In step S105, since the converter control was performed at the previous cycle, the initial differential pressure between the apply pressure PA and the release pressure PR for performing the slip control or the lockup control is set from the map of FIG. 4 according to the throttle opening. . FIG. 4 is a map showing the relationship between the throttle opening and the initial differential pressure. When the throttle opening is small, the initial differential pressure is a constant value, but when the throttle opening is larger than the set value, The differential pressure gradually increases, and then the initial differential pressure becomes constant again.

  In step S106, a flag indicating that open control is performed to shift to slip control or lock-up control is set (fopen_EXE = 1). Further, the countdown of ONTMR for a predetermined time set in advance by a timer (not shown) is started. The predetermined time ONTMR is a mechanical response delay (dead time). The open control will be described in detail in step S109.

  In steps S105 and S106 described above, the initial differential pressure is set as preparation for performing the open control at the first cycle when the control of the lockup clutch 2 shifts from the converter control to the slip control or the lockup control. If the previous cycle is not converter control, step S105 and step S106 are omitted.

  In step S107, it is determined from the flag whether the open control is performed or is being executed. If the flag is set (fopen_EXE = 1), the process proceeds to step S108. If the flag is not set (fopen_EXE = 0), the process proceeds to step S112. This flag is set in step S106 when a transition is made from converter control to slip control or lock-up control, and is set during the slip control or lock-up control, and is set according to the previous cycle when open control is being performed. ing.

In step S108, the actual slip rotation speed Nslp is calculated from the impeller rotation speed Ne and the turbine rotation speed Nt by the actual slip rotation speed calculation unit 21 described later. Further, from the map shown in FIG. 5, a slip rotation speed (hereinafter referred to as an end slip rotation speed) Nslp_end for shifting from the open control to the slip control is calculated based on the throttle opening. FIG. 5 is a map showing the relationship between the accelerator opening and the end slip rotation speed Nslp_end. The end slip rotation speed is constant until the accelerator opening reaches a predetermined value, but when the accelerator opening becomes larger than the predetermined value. The end slip rotation speed also increases according to the accelerator opening. Then, the actual slip rotation speed Nslp and the end slip rotation speed Nslp_end are compared,
Nslp ≦ Nslp_end Formula (1)
Is not satisfied, it is determined that boosting for shifting from the open control to the slip control is not sufficiently performed, and the process proceeds to step S109. If the expression (1) is satisfied, the open control is switched to the slip control. It is determined that boosting for shifting has been sufficiently performed, and the process proceeds to step S110.

  In step S109, open control is continued. Details of this open control will be described later (step S109 constitutes an open control means).

  In step S110, a control system initialization process is performed in order to shift from the open control to the slip control. Although a detailed description of this initialization process is omitted, the procedure described in Japanese Patent Application Laid-Open No. 2000-145949 is used by associating an integrator or the like used in the slip control calculation with the differential pressure command value at the start of the slip control. To initialize.

  In step S111, the flag indicating the open control set in step S106 when shifting from the converter control to the slip control or the lock-up control is cleared (open_EXE = 0). Also, the timer ONTMR is reset for a predetermined time.

  In step S112, the lockup clutch 2 is set to the torque converter 1 in a semi-engaged state, and slip control is performed. In the slip control, control with F / B control is performed so that the actual slip rotation speed becomes the set target slip rotation speed, and a necessary differential pressure command value is calculated. Note that this control includes, for example, Japanese Patent Nos. 0340979, 0183235, and 0230465, and detailed description thereof is omitted here. Further, the boosting operation at the time of shifting from the slip control to the lockup control is performed by the boosting operation using the slip control described in, for example, Japanese Patent Laid-Open No. 2000-240786, but detailed description thereof is omitted here.

  In step S109, the differential pressure command value at the time of open control is set in the above control, and preparation for shifting from the open control to the slip control is performed in steps S110 and S111, and the slip control is performed in step S112.

  When the lockup control of the lockup clutch 2 is completed in step S103, the lockup control is performed in step S113. At this time, the differential pressure is maximum, that is, the apply pressure PA is maximum, the lockup clutch 2 is engaged with the torque converter 1, and the input rotation and the output rotation coincide.

  If lockup control is not selected in step S102, converter control is performed in step 114. As a result, the differential pressure is minimized, that is, the apply pressure PA is minimized, and the lockup clutch 2 is released from the torque converter 1. In the converter control, when the difference between the differential pressure command value at the time of calculation and the minimum pressure is large, the minimum pressure is gradually decreased by a predetermined change amount so that the minimum pressure is not suddenly set. To change.

  With the above control, the engagement state of the lockup clutch 2 and the torque converter 1 is controlled by the throttle opening and the vehicle speed.

  Next, the open control in step S109 will be described with reference to the control configuration diagram of FIG.

  First, in step S200, the target slip rotation speed calculation unit 20 calculates the target slip rotation speed Tslp in the open control based on the accelerator opening degree TVO, which will be described in detail later (step S200 constitutes the target slip rotation speed detection means). To do).

  In step S201, the actual slip rotation speed Nslp is calculated from the difference between the impeller rotation speed Ne detected by the impeller rotation speed sensor 7 in the actual slip rotation speed calculation unit 21 and the turbine rotation speed Nt detected by the turbine rotation speed sensor 8. (Step S201 constitutes an actual slip rotation speed detecting means).

In step S202, the slip rotational speed deviation calculation unit 22 calculates the target slip rotational speed Tslp and the actual slip rotational speed Nslp from
ERRslp = Tslp−Nslp Formula (2)
The slip rotation speed deviation ERRslp is calculated. When the slip rotational speed deviation ERRslp is a positive value, the actual slip rotational speed Nslp is smaller than the target slip rotational speed Tslp, the current boost amount is larger than the target boost amount, and the slip rotation deviation ERRslp is negative. In the case of the value, the actual slip rotation speed Nslp is larger than the target slip rotation speed Tslp, and the current pressure increase amount is smaller than the target pressure increase amount (step S202 constitutes the slip rotation speed deviation calculating means). .

  In step S203, as will be described in detail later, the boost correction coefficient calculator 23 calculates a boost amount correction coefficient K. The boost amount correction coefficient calculation unit 23 includes a slip rotation speed deviation control unit 30 and a correction coefficient calculation unit 31 (step S203 constitutes a fastening force correction value calculation unit).

  In step S204, the basic pressure increase change amount calculation unit 24 calculates a basic pressure increase change amount (basic fastening force increase amount) ΔPLU from the map of FIG. 7 based on the throttle opening TVO. The map of FIG. 7 is a map showing the relationship between the throttle opening TVO and the basic pressure increase change ΔPLU. When the throttle opening TVO increases, the basic pressure increase ΔPLU also increases. Instead of the throttle opening TVO, the amount of pressure increase may be set according to the amount of change in primary rotation described in Japanese Patent Application Laid-Open No. 2004-138150, for example.

In step S205, the boost change calculation unit 25 calculates the basic boost change ΔPLU and the boost correction coefficient K from
ΔPLUadj = ΔPLU × K Equation (3)
Thus, a boost change amount correction value ΔPLUadj that is the current boost amount is calculated.

In step S206, the lockup clutch engagement pressure command value calculation unit 26 determines from the previous lockup clutch engagement pressure command value PLUC_z and the pressure increase change amount correction value ΔPLAddj.
PLUC = PLUC_z + ΔPLUAdj Expression (4)
To calculate a lockup clutch engagement pressure command value PLUC (hereinafter, engagement pressure command value). The current engagement pressure command value PLUC is used as the engagement pressure command value PLUC_z in the next control.

  In step S207, the solenoid drive signal calculation unit 27 calculates the lockup duty SDUTY so that the engagement force between the torque converter 1 and the lockup clutch 2 becomes the engagement pressure command value PLUC.

  The fastening pressure command value PLUC is calculated by the above control, and the pressure is increased by open control.

  Next, a method of calculating the target slip rotation speed Tslp performed by the target slip rotation speed calculation unit 20 in step S200 will be described using the flowchart of FIG.

  When the open control is started in step S106, the count-down of a predetermined time ONTMR is started. In step S300, whether or not a predetermined time has elapsed since the start of the open control is determined whether ONTMR = 0. . If ONTMR = 0, the process proceeds to step S301. If ONTMR = 0 is not satisfied, the process proceeds to step S305.

In step S301, the turbine rotational speed sensor 8 calculates the current turbine rotational speed Nt, and reads the turbine rotational speed Nt_z of the previous cycle,
ΔNt = Nt−Nt_z (5)
Thus, the turbine rotation speed change amount ΔNt from the previous cycle to the current cycle is calculated. Further, although the turbine rotational speed Nt_z of the previous cycle is used here, an average value per cycle may be used by using a value before a predetermined period (predetermined cycle) set in advance. In this case, even when the turbine rotational speed Nt increases while oscillating, since the evaluation is performed using data between a plurality of cycles, it is possible to prevent a vibrational change in the turbine rotational speed change amount ΔNt.

  In step S302, a target engine speed change amount (impeller rotation speed change amount) ΔNe to be changed in the current cycle is set based on the throttle opening TVO from the map shown in FIG. 9 is a map showing the relationship between the accelerator opening and the target engine speed change amount ΔNe. When the throttle opening TVO is smaller than the predetermined throttle opening, the target engine speed change amount ΔNe is constant. However, if the throttle opening is larger than the predetermined throttle opening, the target engine speed change amount ΔNe also increases.

In step S303, from the turbine rotation speed change amount ΔNt and the target engine rotation speed change amount ΔNe,
ΔTslp = ΔNe−ΔNt (6)
Is used to calculate the target slip rotation speed change amount ΔTslp.

In step S304, the target slip rotation speed Tslp in the current cycle is calculated from the target slip rotation speed Tslp_z and the target slip rotation speed change amount ΔTslp in the previous cycle.
Tslp = Tslp_z + ΔTslp (7)
Calculated by The current target slip rotation speed Tslp is used as the target slip rotation speed Tslp_z in the next cycle.

  On the other hand, if it is determined in step S300 that ONTMR = 0 is not satisfied, in step S305, the impeller rotational speed sensor 7 calculates the impeller rotational speed Ne and the turbine rotational speed sensor 8 to calculate the impeller rotational speed Ne. And the actual slip rotation speed Nslp is calculated from the difference between the turbine rotation speed Nt and the turbine rotation speed Nt. Then, the actual slip rotation speed Nslp is set as the target slip rotation speed Tslp. Thus, the actual slip rotation speed Nslp is set as the initial value of the target slip rotation speed Tslp_z of the previous cycle in the equation (7) at the next cycle.

  The target slip rotation speed Tslp targeted in the current cycle is calculated by the above control. Note that the target slip rotation speed Tslp is a method of gradually decreasing from the actual slip rotation speed Nslp at the start of the open control, as described in, for example, Japanese Patent No. 03240979, such that the target slip rotation speed Tslp becomes a target slip rotation speed set after the elapse of a predetermined time. A filter output with the current slip rotation speed as an initial value may be used.

  Next, a calculation method of the boost amount correction coefficient K in the boost amount correction coefficient calculation unit 23 in step S203 will be described with reference to the flowchart of FIG.

  In step S400, it is determined whether or not the predetermined time ONTMR that has started the countdown in step S106 becomes ONTMR = 0, that is, whether or not the predetermined time ONTMR has elapsed since the start of the open control. If ONTMR = 0, the process proceeds to step S401. If ONTMR = 0 is not satisfied, the process proceeds to step S410.

  In step S401, an error selection flag for correction coefficient reference (hereinafter, error selection flag) ERRselect is determined. If the error selection flag ERRselect is 0 (not selected), the process proceeds to step S402, and the error selection flag ERRselect is not 0. If (selected), the process proceeds to step S406. Here, when the error selection flag ERRselect is 0, a flag indicating that the open control is being executed is set (open_EXE = 1) in step S106 after the open control is started, and the slip rotation speed deviation ERRslp is a predetermined value described later. This is a case where the slip rotational speed deviation P_ERR or M_ERR is not exceeded.

  In step S402, the slip rotation speed deviation ERRslp calculated in step S202 is compared with a predetermined slip rotation speed deviation P_ERR (positive value) set in advance, and the slip rotation speed deviation ERRslp is larger than the predetermined slip rotation speed deviation P_ERR. If the actual slip rotational speed Nslp is smaller than the target slip rotational speed Tslp and the difference is larger than the predetermined slip rotational speed deviation P_ERR, the process proceeds to step S403, where the slip rotational speed deviation ERRslp is the predetermined slip rotational speed. If it is smaller than the speed deviation P_ERR, the process proceeds to step S404. The predetermined slip rotation speed deviation P_ERR is a value for determining whether or not the boost change amount correction coefficient K is set to 1 in accordance with a slip rotation speed deviation limit value ERRslp_adj in step S412 described later.

  In step S403, the error selection flag ERRselect is set to 1.

  In step S404, the slip rotation speed deviation ERRslp calculated in step S202 is compared with a predetermined slip rotation speed deviation M_ERR (negative value) set in advance, and the slip rotation speed deviation ERRslp is smaller than the predetermined slip rotation speed deviation M_ERR. If the actual slip rotation speed Nslp is larger than the target slip rotation speed Tslp and the absolute value of the difference is larger than the absolute value of the predetermined slip rotation speed deviation M_ERR, the process proceeds to step S405, where the slip rotation speed deviation is determined. If ERRslp is greater than the predetermined slip rotation speed deviation M_ERR, the process proceeds to step S409. The predetermined slip rotation speed deviation M_ERR is a value for determining whether or not the step-up change correction coefficient K is set to 1 in accordance with a slip rotation speed deviation limit value ERRslp_adj in step S412 described later (steps S402 and S404 are slips). Constitutes a rotation speed comparison means).

  In step S405, the error selection flag ERRselect is set to 2.

  If it is determined in step S401 that the error selection flag ERRselect is other than 0, it is determined in step S406 whether the error selection flag ERRselect is 1 or 2. If the error selection flag ERRselect is 1, that is, if the error selection flag ERRselect is set to 1 in step S403 in the previous cycle, the process proceeds to step S407, and if the error selection flag ERRselect is 2, that is, step in the previous cycle. When the error selection flag ERRselect is set to 2 in S405, the process proceeds to step S408 (step S406 constitutes a storage unit).

  In step S407, the slip rotation speed deviation ERRslp is limited to a value equal to or greater than 0, and is set as a slip rotation speed deviation limit value ERRslp_adj. Thus, the boost amount correction value coefficient K calculated in step S412 described later is set to 1 or less.

  On the other hand, in step S408, the slip rotation speed deviation ERRslp is limited to a value equal to or less than 0 to obtain a slip rotation speed deviation limit value ERRslp_adj. As a result, the boost amount correction value coefficient K calculated in step S412 to be described later is set to 1 or more (steps S407 and S408 constitute correction value limiting means).

  From the above control, when the error selection flag ERRselect is set in step S403 and step S405, the flag once set is not changed unless it is initialized in step S411 described later.

  If it is determined in step S404 that the slip rotation speed deviation ERRslp is larger than the predetermined slip rotation speed deviation M_ERR, that is, the error selection flag ERRselect is not set, and the slip rotation speed deviation ERRslp is larger than the predetermined rotation speed M_ERR. When the rotational speed is smaller than the predetermined rotational speed P_ERR, the process proceeds to step S409. However, in step S409, the slip rotational speed deviation ERRslp is not limited to the slip rotational speed deviation ERRslp in step S412 described later. Let it be the value ERRslp_adj.

  In step S400, if ONTMR is not ONTMR = 0 for the predetermined time, the process proceeds to step S410.

  In step S410, the error selection flag ERRselect is initialized, that is, the error selection flag ERRselect is set to 0 (step S410 constitutes an erasing unit).

  In step S411, since the error selection flag ERRselect is set to 0, the slip rotation speed deviation ERRslp is set to the slip rotation speed deviation limit value ERRslp_adj, and the slip rotation speed deviation limit value ERRslp_adj is set to 0. Accordingly, even when the open control is started, the boosting amount is not corrected during the time when the mechanical response delay occurs, so that it is possible to prevent the boosting amount from being excessively increased.

In step S412, the boost amount correction coefficient K is calculated from the map of FIG. 11 based on the slip rotation speed deviation limit value ERRslp_adj set in step S407, step S408, step S409, and step S411. The map of FIG. 11 is a map showing the relationship between the slip rotation speed deviation limit value ERRslp_adj and the boost amount correction coefficient K. The slip rotation speed deviation limit value ERRslp_adj is
M_ERR ≦ ERRslp_adj ≦ P_ERR Formula (8)
In this case, the pressure increase correction coefficient K is 1, and when the slip rotation speed deviation limit value ERRslp_adj is smaller than the predetermined slip rotation speed deviation M_ERR, the pressure increase correction coefficient K is larger than 1, and the slip rotation speed is increased. When the deviation limit value ERRslp_adj is larger than the predetermined slip rotation speed deviation P_ERR, the boost amount correction coefficient K is smaller than 1. As a result, when the slip rotation speed deviation limit value ERRslp_adj satisfies the equation (8), that is, when the slip rotation speed deviation ERRslp is small (including step S411), the boost amount correction coefficient K is set to 1, and the basic boost change ΔPLU The pressure is boosted by the basic pressure increase change amount ΔPLU based on the throttle opening TVO shown in FIG. When the error selection flag is set to 1, the boosting amount correction coefficient K is set to 1 or less, the basic boosting change amount ΔPLU is corrected by the equation (3), and the basic boosting amount ΔPLU is set as the upper limit value. Boosting is performed with the change amount correction value ΔPLUadj. When the error selection flag is set to 2, the boost amount correction coefficient K is set to 1 or more, the basic boost change amount ΔPLU is corrected by the equation (3), and the basic boost change amount ΔPLU is set as the lower limit value. Boosting is performed with the change amount correction value ΔPLUadj.

  By the above control, when the slip rotation speed deviation ERRslp exceeds a predetermined slip rotation speed deviation (M_ERR, P_ERR), the basic step-up change ΔPLU is corrected by the boost amount correction coefficient K, so that the target slip rotation speed Tslp Boosting can be performed following the above.

  Also, the open control is started, and when the slip rotation speed deviation ERRslp exceeds a predetermined slip rotation speed deviation (M_ERR, P_ERR), the error selection flag ERRselect is set, and the error selection flag ERRselect is maintained during the open control. Therefore, even when the sign of the slip rotational speed deviation ERRslp changes during the open control, that is, when the relationship between the target slip rotational speed Tslp and the actual slip rotational speed Nslp is switched, the boost amount correction coefficient K is set to 1, that is, the basic In order to set the step-up change amount ΔPLU as a limit value, the amount of change in the step-up amount can be reduced, and step-up can be performed following the target slip rotation speed Tslp. In addition, since the basic boost amount ΔPLU is not corrected transiently, hunting can be prevented.

  Next, changes in engine rotational speed (impeller rotational speed) Ne and the like when the present invention is not used and when the present invention is used will be described with reference to time charts of FIGS. 12, 13, and 14.

  FIG. 12 is a time chart when the pressure increase amount during the open control is set according to the change amount of the throttle opening without using the present invention. FIG. 13 is a time chart when boosting is performed by feedback control when shifting from converter control to slip control without using the present invention. FIG. 14 is a time chart when the present invention is used.

  First, FIG. 12 will be described. At time t0, the vehicle starts from a stopped state, and the torque converter 1 first performs converter control. Note that the throttle opening TVO is constant. In the converter control, the lockup control valve 3 does not boost the pressure, so that the basic pressure change amount ΔPLU and the engagement pressure command value PLUC are constant. The engine rotation speed (impeller rotation speed) Ne and the turbine rotation speed Nt increase.

  At time t1, the transition from the converter control to the slip control is started, and the open control is started. Since boosting is performed by open control, the basic boosting change amount ΔPLU is a certain boosting amount, and the engagement pressure command value PLUC increases with time. The engine speed Ne is reduced by increasing the pressure by open control. The broken line in the engine speed at this time indicates the target engine speed.

  Since the slip rotation speed Nslp, which is the difference between the engine rotation speed Ne and the turbine rotation speed Nt, decreases and reaches the end slip rotation speed Nslp_end at time t2, the control shifts from the open control to the slip control. At this time, since the basic pressure increase amount change ΔPLU is set according to the throttle opening TVO, for example, even when the slip rotation speed deviation ERRslp is large, the pressure is increased by the basic pressure increase change amount ΔPLU. The transition time from slip to slip control becomes longer.

  Next, FIG. 13 will be described. At time t0, the vehicle starts from a stopped state, and the torque converter first performs converter control. Note that the throttle opening TVO is constant. In the converter control, the lockup control valve 3 does not boost the pressure, so that the basic pressure change amount ΔPLU and the engagement pressure command value PLUC are constant. The engine rotation Ne and the turbine rotation Nt increase.

  At time t1, the converter control is shifted to the slip control, and the voltage is boosted using the feedback control used in the slip control. The actual fastening pressure at this time is indicated by a dotted line. Although the actual engagement pressure has a mechanical delay with respect to the engagement pressure command value PLUC, when feedback control is performed, hunting is caused by excessive pressure increase to increase the amount of pressure increase in order to correct slip rotational speed deviation caused by the delay. Occurs.

  Next, FIG. 14 is a time chart when the present invention is used, and FIG. 14 will be described.

  At time t0, the vehicle starts from a stopped state, and the torque converter first performs converter control. Note that the throttle opening TVO is constant. In converter control, boosting is not performed by the lockup control valve 3, and therefore the boosting change amount correction amount ΔPLUAdj and the engagement pressure command value PLUC are constant. The engine rotation Ne and the turbine rotation Nt increase.

  At time t1, the transition from the converter control to the slip control is started, and the open control is started. Then, the countdown by the timer is started (step S106). During the countdown, the boosting amount correction coefficient K is set to 1, and the boosting is performed without correcting the basic boosting change amount ΔPLU.

  When the countdown ends at time t2, a boost amount correction coefficient K is calculated based on the slip rotation speed deviation ERRslp. Here, since the slip rotation speed deviation ERRslp (slip rotation speed deviation limit value ERRslp_adj) satisfies the relationship of Expression (8), the boost amount correction coefficient K is 1, and the boost is performed without correcting the basic boost change amount ΔPLU. Do.

  Since the slip rotation speed deviation ERRslp becomes larger than the predetermined slip rotation speed deviation P_ERR at time t3, the pressure increase change amount correction amount ΔPLUadj is decreased. In the present invention, the error selection flag ERRselect is set to 1 (step S403), the slip rotation speed deviation limit value ERRslp_adj is limited to 0 or more (step S407), and the boost amount correction coefficient K is calculated from the map shown in FIG. Since the basic boosting change amount ΔPLU is corrected, the basic boosting change amount correction value ΔPLUadj changes with the correction. Here, since the boosting change amount correction amount ΔPLUadj is decreased, the boosting amount correction coefficient K is a value smaller than 1, and the boosting change amount correction value ΔPLUadj is smaller than the basic boosting change amount ΔPLU (in the figure, the dotted line indicates the basic boosting amount). The amount of change ΔPLU is shown).

  Since the slip rotational speed deviation ERRslp becomes smaller than the predetermined slip rotational speed deviation P_ERR at time t4, the boosting amount correction coefficient K is set to 1, and the basic boosting change amount ΔPLU is boosted without correction.

  At time t5, the actual slip rotation speed Nslp becomes larger than the target slip rotation speed Tslp, and the sign of the slip rotation speed deviation ERRslp is reversed. However, in the present invention, since the error selection flag ERRselect once set during the open control is not reset during the open control, the boost amount correction coefficient K is set to 1 to limit the slip rotation speed deviation limit value ERRslp_adj to 0 or more. Boosting is performed without correcting the boosting change amount ΔPLU.

  Since the slip rotation speed Nslp becomes the open control end rotation Nslp_end at time t6, the control shifts from the open control to the slip control. Further, the timer is reset, ONTMR is set for a predetermined time, and the error selection flag ERRselect is set to 0.

  As described above, by setting the pressure increase correction coefficient K in accordance with the slip rotation speed deviation ERRslp, it is possible to quickly increase the pressure following the target slip rotation speed Tslp in which the pressure increase is set in advance. In addition, by maintaining the error selection flag ERRselect once set, the basic boost change ΔPLU is set to a limit value (upper limit or lower limit), so that the basic boost change ΔPLU is not transiently corrected, thereby preventing hunting. can do.

  When making a determination at each step, it is possible to set a hysteresis for the determination value to prevent hunting of the determination result.

  The effect of 1st Embodiment of this invention is demonstrated.

  In the open control, the basic pressure increase change amount ΔPLU is corrected based on the slip rotation speed deviation ERRslp, so that it is possible to perform pressure increase that follows the preset target slip rotation speed Tslp.

  When the actual slip rotation speed Nslp is larger than the target slip rotation speed Tslp and the slip rotation speed deviation ERRslp is smaller than the predetermined slip rotation speed deviation M_ERR, the boost amount correction coefficient K is set larger than 1, so By increasing the amount correction value ΔPLUadj above the basic pressure increase change amount ΔPLU, it is possible to perform pressure increase following the target slip rotation speed Tslp, and therefore it is possible to quickly end pressure increase by open control.

  When the actual slip rotation speed Nslp is lower than the target slip rotation speed Tslp, if the pressure is increased as it is with the basic pressure increase change amount ΔPLU, the shift to the slip control in which the feedback control is performed causes excessive pressure increase and the shift to the slip control is performed. Hunting occurs. However, in the present invention, when the actual slip rotation speed Nslp is smaller than the target slip rotation speed Tslp and the slip rotation speed deviation ERRslp is larger than the predetermined slip rotation speed deviation P_ERR, the step-up change correction coefficient K is smaller than 1. Therefore, the boosting change amount correction value ΔPLUadj is made smaller than the basic boosting change amount ΔPLU, so that excessive boosting can be suppressed and hunting can be prevented. Moreover, the pressure | voltage rise which followed target slip rotational speed Tslp can be performed.

  When the open control is started and the slip rotation speed deviation ERRslp exceeds the predetermined slip rotation speed deviation M_ERR or the predetermined slip rotation speed deviation P_ERR, the error selection flag ERRselect is set to 1 or 2, and then the open control ends. The error selection flag ERRselect is maintained until the basic boosting change amount ΔPLU is set to the upper limit value or the lower limit value based on the error selection flag ERRselect. Therefore, for example, the sign of the slip rotational speed deviation ERRslp is reversed in the middle of the open control, that is, the target slip rotational speed Tslp is compared with the actual slip rotational speed Nslp. Therefore, it is possible to perform boosting following the target slip rotation speed Tslp. Moreover, hunting can be prevented.

  Since ONTMR for the predetermined time immediately after the start of the open control does not correct the basic boost amount ΔPLU, it is possible to prevent an excessive boost due to the mechanical delay after the start of the open control.

  It goes without saying that the present invention is not limited to the above-described embodiments, and includes various modifications and improvements that can be made within the scope of the technical idea.

  It can be used for a vehicle equipped with a torque converter.

1 is a schematic configuration diagram of the present invention. It is a flowchart which shows the operation control of the lockup clutch of this invention. It is a map which shows the control method of the lockup clutch by the vehicle speed and throttle opening of this invention. It is a map which shows the relationship between the throttle opening at the time of shifting to the slip control from the converter control of this invention, and an initial differential pressure | voltage. It is a map which shows the relationship between the throttle opening degree of this invention, and completion | finish slip rotational speed. It is a control block diagram which shows the open control of this invention. It is a map which shows the relationship between the throttle opening of this invention, and basic pressure | voltage rise change amount. It is a flowchart for calculating the target slip rotation speed of this invention. It is a map which shows the relationship between the throttle opening of this invention, and target engine rotation variation | change_quantity. 5 is a flowchart for calculating a boost amount correction coefficient according to the present invention. It is a map which shows the relationship between the slip rotational speed deviation limiting value of this invention, and a pressure | voltage rise correction coefficient. 6 is a time chart showing changes in engine rotation, turbine rotation, engagement pressure command value, basic pressure increase amount, and throttle opening when the present invention is not used. 6 is a time chart showing changes in engine rotation, turbine rotation, fastening pressure command value, slip rotation speed deviation, and throttle opening when the present invention is not used. Engine rotation, turbine rotation, fastening pressure command value, pressure increase change correction value, target slip rotation speed, actual slip rotation speed, slip rotation speed deviation, slip rotation speed deviation limit value, error selection flag when using the present invention, It is a time chart which shows the change of a pressure increase correction coefficient, a timer, and a throttle opening.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Torque converter 2 Lock-up clutch 3 Lock-up clutch control valve 5 Controller 7 Impeller rotation sensor (impeller rotation speed detection means)
8 Turbine rotation sensor (turbine rotation speed detection means)
DESCRIPTION OF SYMBOLS 10 Throttle opening sensor 20 Target slip rotational speed calculating part 21 Actual slip rotational speed calculating part 22 Slip rotational speed deviation calculating part 23 Boosting correction coefficient calculating part 25 Boosting change amount calculating part

Claims (5)

A torque converter that transmits the power of the prime mover and has a lock-up clutch;
Open control means for controlling the engagement state of the lockup clutch by open loop control based on the driving state of the vehicle;
Turbine rotation speed detection means for detecting the turbine rotation speed of the torque converter;
Impeller rotation speed detection means for detecting the impeller rotation speed of the torque converter;
Slip rotation speed detection means for calculating an actual slip rotation speed based on the turbine rotation and the impeller rotation speed;
Target slip rotation speed calculating means for calculating the target slip rotation speed during the open loop control;
Slip rotation speed deviation calculating means for calculating a slip rotation speed deviation between the target slip rotation speed and the actual slip rotation speed;
Engagement force correction value calculation means for calculating a correction value for correcting the basic engagement force increase amount of the lockup clutch based on the slip rotation speed deviation, and
The opening control means increases the fastening force of the lockup clutch according to the correction value.   2. The engagement force correction value calculating means multiplies the basic engagement force increase amount of the lockup clutch by 1 when the slip rotation speed deviation is within a predetermined range. Lockup clutch tightening force control device. The fastening force correction value calculating means includes
Slip rotation speed comparison means for comparing the target slip rotation speed with the actual slip rotation speed;
When the slip rotation speed deviation exceeds a predetermined range and the target slip rotation speed is larger than the actual slip rotation speed, a correction value is calculated with the basic fastening force increase amount as a lower limit, and the slip rotation speed deviation is Correction value limiting means for calculating a correction value with the amount of increase in the basic fastening force as an upper limit when the target slip rotation speed exceeds a predetermined range and the actual slip rotation speed is smaller than the actual slip rotation speed. The fastening force control device for a lockup clutch according to claim 2. The fastening force correction value calculating means includes
Storage means for storing the result of the slip rotation speed comparison means;
Erasing means for erasing the result of the slip rotation speed comparison means when ending the open loop control,
4. The lockup clutch engagement force control according to claim 3, wherein the basic engagement force increase amount is corrected based on the storage means unless the result of the slip rotation speed comparison means is erased by the erasure means. apparatus.   5. The lockup according to claim 1, wherein the open control does not perform the correction by the fastening force correction value calculation means for a predetermined time after the open loop control is started. Clutch engagement force control device.

Images