JP2006200422A - Control device for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control unit of an automatic transmission which can realize comfortable start even when a sufficient amount of oil cannot be ensured due to time degradation of oil or the like at the time of re-starting an engine after idling stop. <P>SOLUTION: An engagement pressure control means issues to an engine control unit a command to reduce torque of an engine so that the torque does not exceed the engagement capacity of a start clutch in an engagement phase. When a difference between a number of revolutions of a turbine and a number of revolutions of an input shaft of the transmission after completion of the engagement phase, is larger than a predetermined value, an engine torque reducing command is issued to set the engine torque limitation amount after the completion of the engagement phase larger than a predetermined value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control device for an automatic transmission having an idle stop control, and more particularly to a control device for a belt-type continuously variable transmission.

As a control device for an automatic transmission having an idle stop control, a technique described in Patent Document 1 is disclosed. In this publication, the end of the precharge phase is detected when the engine speed after the engine restarts exceeds a predetermined value, and the start clutch engagement control (so-called ND select control) is detected by shifting to the engagement phase. )It is carried out.
JP 2000-266172 A

  Here, the amount of oil charged in the starting clutch is affected by the rotational speed dependency of the pump volumetric efficiency and the size of various valve leaks, so it is difficult to accurately predict the amount of oil charged. Further, there is a problem that the amount of filled oil is greatly affected by deterioration with time of the oil pump and valve system. Therefore, in the technique described in Patent Document 1, it is doubtful whether the starting clutch is actually sufficiently filled with oil simply by predicting the end of the precharge phase based on the engine speed. In general, during ND selection control, the engine speed is controlled to be kept at an idle speed until the start clutch is completely engaged. In this state, if the initial phase of the starting clutch is insufficient and the engagement phase is entered, it will take time to complete the engagement, especially after restarting, when the accelerator pedal is depressed and all development progresses, it will move forward. There was a risk that the clutch would suddenly engage and a large starting shock would occur.

  The present invention has been made paying attention to the above-mentioned problem, and even when the engine is restarted after an idle stop, even when a sufficient amount of oil cannot be secured due to deterioration over time or the like, automatic transmission that can start without a sense of incongruity It is an object of the present invention to provide a control device for a machine.

  To achieve the above object, according to the present invention, an oil pump driven by an engine, a starting clutch fastened by a fastening pressure using the oil pump as a hydraulic source when the vehicle starts, and a state in which the starting clutch is disengaged from a released state. And the fastening pressure control means for performing the fastening pressure control through the fastening phase, and when the vehicle is stopped and the predetermined condition is satisfied, the engine is stopped and the predetermined condition is not satisfied. And an idle stop control means for restarting the engine, wherein the engagement pressure control means reduces the engine torque so as not to exceed the engagement capacity of the starting clutch in the engagement phase. The command is output to the engine control unit, and the turbine rotational speed and transmission input shaft rotational speed after completion of the engagement phase are Is equal to or greater than the predetermined value, it was decided to output a torque-down command of the engine to a subsequent engine torque restriction rate to or larger than a predetermined value.

  When the engine is restarted after idling stop, the amount of oil actually filled in the start clutch can be accurately estimated, and the start clutch engagement control is changed based on this amount of oil to prevent delay in clutch engagement timing. It is possible to achieve a start without a sense of incongruity.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for realizing an automatic transmission control apparatus according to the present invention will be described below based on embodiments shown in the drawings.

  FIG. 1 is a diagram illustrating a control system of an automatic transmission including a belt type continuously variable transmission 3 (hereinafter referred to as CVT) in the first embodiment.

  1 is a torque converter, 2 is a lock-up clutch, 3 is a CVT, 4 is a primary rotational speed sensor, 4a is a turbine rotational speed sensor, 5 is a secondary rotational speed sensor, 6 is a hydraulic control valve unit, and 8 is driven by an engine Oil pump, 9 is a CVT control unit, 10 is an accelerator opening sensor, 11 is an oil temperature sensor, 12 is a steering angle sensor that detects the steering angle of the steering wheel, 13 is an idle stop switch, 14 is a vehicle speed sensor, and 15 is a brake. Brake switch for detecting ON / OFF of pedal, 16 for line pressure sensor for detecting line pressure, 17 for idle stop control unit, 18 for engine control unit, 19 for engine, 19a for starter motor, 19b for engine output shaft is there.

  The engine output shaft 19b is connected to the oil pump 8 and the torque converter 1 as a rotation transmission mechanism, and is provided with a lockup clutch 2 that directly connects the engine 19 and the CVT 3. A turbine shaft 1 a is connected to the output side of the torque converter 1, and the turbine shaft 1 a is connected to a ring gear 21 of the forward / reverse switching mechanism 20. The forward / reverse switching mechanism 20 includes a planetary gear mechanism including a ring gear 21 connected to the turbine shaft 1a, a pinion carrier 22, and a sun gear 23 connected to the transmission input shaft 1b. The pinion carrier 22 is provided with a reverse brake 24 that fixes the pinion carrier 22 to the transmission case, and a forward clutch 25 (starting clutch) that integrally connects the transmission input shaft 1b and the pinion carrier 22.

  A primary pulley 30a of the CVT 3 is provided at the end of the transmission input shaft 1b. The CVT 3 includes the primary pulley 30a, the secondary pulley 30b, a belt 34 that transmits the rotational force of the primary pulley 30a to the secondary pulley 30b, and the like. The primary pulley 30a is fixed by a fixed conical plate 31 that rotates integrally with the transmission input shaft 1b and a V-shaped pulley groove that is disposed opposite to the fixed conical plate 31 and is shifted by hydraulic pressure acting on the primary pulley cylinder chamber 33. The movable conical plate 32 is movable in the axial direction of the machine input shaft 1b.

  The secondary pulley 30 b is provided on the driven shaft 38. The secondary pulley 30 b has a fixed conical plate 35 that rotates integrally with the driven shaft 38, a V-shaped pulley groove that is disposed so as to face the fixed conical plate 35, and is driven by hydraulic pressure that acts on the secondary pulley cylinder chamber 37. The movable conical plate 36 is movable in the axial direction.

  A drive gear (not shown) is fixed to the driven shaft 38, and this drive gear drives a drive shaft that reaches a wheel (not shown) via a pinion, a final gear, and a differential gear provided on the idler shaft.

  The rotational force input from the engine output shaft 12 to the CVT 3 as described above is transmitted to the transmission input shaft 1 b via the torque converter 1 and the forward / reverse switching mechanism 20. The rotational force of the transmission input shaft 1b is transmitted to the differential device through the primary pulley 30a, belt 34, secondary pulley 30b, driven shaft 38, drive gear, idler gear, idler shaft, pinion, and final gear.

  During the power transmission as described above, by moving the movable conical plate 32 of the primary pulley 30a and the movable conical plate 36 of the secondary pulley 30b in the axial direction to change the contact position radius with the belt 34, the primary pulley 30a The rotation ratio between the secondary pulley 30b, that is, the gear ratio can be changed. Control for changing the width of the V-shaped pulley groove is performed by hydraulic control to the primary pulley cylinder chamber 33 or the secondary pulley cylinder chamber 37 via the CVT control unit 9.

  The CVT control unit 9 includes a turbine rotational speed Nt from the turbine rotational speed sensor 4 a, a throttle opening TVO from the throttle opening sensor 10, a transmission oil temperature f from the oil temperature sensor 11, and a primary rotational speed sensor 4. The primary rotational speed Npri, the secondary rotational speed Nsec from the secondary rotational speed sensor 5, the line pressure from the line pressure sensor 16, and the like are input. A control signal is calculated based on this input signal, and the control signal is output to the hydraulic control valve unit 6.

  A control signal from the CVT control unit 9 is input to the hydraulic control valve unit 6, and shift control is performed by supplying control pressure to the primary pulley cylinder chamber 33 and the secondary pulley cylinder chamber 37.

  Sensor signals from the rudder angle sensor 12, the idle stop switch 13, the vehicle speed sensor 14, and the brake switch 15 are input to the idle stop control unit 17, and sensor signals, torque down control signals, and the like are mutually transmitted to the CVT control unit 9. Are communicating. When the idling stop control unit 17 determines that idling is stopped, a command to stop idling is output to the engine control unit 18.

  If it is determined that the engine is restarted after the idle stop, an engine restart command is output to the engine control unit 18, and the engine control unit 18 outputs a motor drive signal to the starter motor 19a. Start.

  In addition, an idle stop command or the like output from the idle stop control unit 17 is output to, for example, a hill hold control unit or the like provided in the brake unit so as to prevent the vehicle from retreating at an idle stop on an inclined road surface or the like. It may be configured. Further, at the time of restart, a torque down amount corresponding to the engaged state of the forward clutch 25 is input, and the engine output state is controlled according to the torque down amount.

  FIG. 2 is a circuit diagram illustrating a hydraulic circuit of the belt type continuously variable transmission according to the first embodiment. The pressure regulator valve 40 regulates the discharge pressure of the oil pump 8 supplied from the oil passage 8a as a line pressure (pulley clamp pressure). An oil passage 8b communicates with the oil passage 8a. The oil passage 8 b is a pulley clamp pressure supply oil passage that supplies a pulley clamp pressure for clamping the belt 34 to the primary pulley cylinder chamber 33 and the secondary pulley cylinder chamber 37 of the CVT 3. An oil passage 8e communicating with the oil passage 8b supplies the original pressure of the pilot valve 50.

  The clutch regulator valve 45 adjusts the forward clutch pressure using the hydraulic pressure drained from the pressure regulator valve 40 as a source pressure. The pressure regulator valve 40 and the clutch regulator valve 45 communicate with each other via an oil passage 41. In addition, the oil passage 41 communicates with the line pressure oil passage 8c and an oil passage 8d having an orifice 8f. Further, the oil passage 41 communicates with the oil passage 42 for supplying the hydraulic pressure adjusted by the clutch regulator valve 45 to the select switching valve 75 and the select control valve 90.

  The pilot valve 50 sets a constant supply pressure to the lockup solenoid 71 and the select switching solenoid 70 via the oil passage 51. The output pressure of the select switching solenoid 70 is supplied from the oil passage 70 a to the select switching valve 75 to control the operation of the select switching valve 75. The output pressure of the lockup solenoid 71 is supplied to the select switching valve 75 from the oil passage 71a.

  When the signal of the select switching solenoid 70 is ON, the signal pressure of the lockup solenoid 71 acts as the signal pressure of the select control valve 90 via the select switching valve 75. When the signal of the select switching solenoid 70 is OFF, the signal pressure of the lockup solenoid 71 is led to a lockup control valve (not shown) through the select switching valve 75.

  When the signal of the select switching solenoid 70 is zero and the signal of the lockup solenoid 71 is also zero, the signal pressure to the select control valve 90 is zero. At this time, the spool valve 92 is moved rightward in the figure by the spring load of the return spring 91 of the select control valve 90.

  Both the pressure regulator valve 40 and the clutch regulator valve 45 are regulated by the pressure modifier pressure. The pressure modifier pressure is a signal pressure that regulates the pressure modifier valve 73 supplied with the line pressure by the line pressure solenoid 72, and is regulated as a signal pressure higher than the signal pressure by the solenoids 70, 71, and 72.

  By adjusting the pressure with a signal pressure higher than the signal pressure by the solenoid 72, the pressure adjustment performance in the high pressure region is improved (corresponding to the second fastening means). On the other hand, the pressure regulated by the signal pressure by the solenoid 71 enables fine regulation in the low pressure region, but the maximum pressure that can be regulated is limited (corresponding to the fastening pressure means).

  In the forward clutch 25 engagement control of the first embodiment, the engagement pressure control after shifting to the fully engaged state is performed by the clutch regulator valve 45, and for example, at the time of starting engagement control before shifting to the fully engaged state. Thus, the fastening pressure control by the lockup solenoid 71 is executed. When performing the engagement control from the forward clutch 25 disengaged state, the select switching solenoid 70 is turned ON, so that the oil passage 42 and the oil passage 77 are disconnected, and the oil pressure in the oil passage 42 passes through the select control valve 90. Then, the oil passage 77 is configured to be supplied. At the same time, the signal pressure of the lock-up solenoid 71 is configured so as to be in communication with a lock-up control valve (not shown) and supplied as a counter pressure of the select control valve 90. As a result, the signal pressure of the lockup solenoid 71 controls the engagement pressure of the forward clutch 25 in the oil passage 42 by the select control valve 90. This makes it possible to control the engagement pressure more finely than the clutch regulator valve 45.

  When the above engagement control is completed, the select switching solenoid 70 and the lockup solenoid 71 are turned off, and the oil passage 42 and the oil passage 77 are communicated, whereby the engagement pressure of the forward clutch 25 is adjusted by the clutch regulator valve 45. It is assumed that the pressure is supplied as it is. In the first embodiment, the configuration for switching the engagement control of the forward clutch 25 as described above is defined as the source pressure switching type.

  FIG. 3 is a flowchart showing the basic control contents of the idle stop control in the first embodiment.

  In step 101, it is determined whether the idle stop permission flag is ON, the idle stop switch is energized, the vehicle speed is 0, the brake switch is ON, the steering angle is 0, etc., and the process proceeds to step 102 only when all the conditions are satisfied. Otherwise, idle stop control is ignored.

  In step 102, it is determined whether or not the selected position is the travel range. If the travel position is the travel range, the process proceeds to step 103. Otherwise, the process proceeds to step 104.

  In step 103, it is determined whether the oil temperature Toil is higher than the lower limit oil temperature Tlow and lower than the upper limit oil temperature Thi. If the condition is satisfied, the process proceeds to step 104. Otherwise, the process proceeds to step 101.

  In step 104, the engine 10 is stopped.

  In step 105, it is determined whether or not the brake switch 2 is OFF.

  In step 106, engine restart control is executed.

  That is, if the driver desires idle stop control, the vehicle is stopped, the brake is depressed, and the steering angle is 0, the engine is stopped. Here, the idle stop switch conveys the intention of the driver to execute or cancel the idle stop. This switch is energized when the ignition key is turned. The reason why the rudder angle is 0 is that, for example, idle stop is prohibited when the vehicle is temporarily stopped during traveling such as when turning right.

  The idle stop permission flag is set by other control logic or the like, and is set when undesirable engine restart control cannot be achieved even when idle stop is performed. Specific examples include a case where the engagement control of the forward clutch 25 described later is not successful, and a case where the starter motor 19a cannot be driven due to insufficient charge of the battery, but is not particularly limited.

  Next, it is determined whether the oil temperature Toil is higher than the lower limit oil temperature Tlow and lower than the upper limit oil temperature Thi. This is because if the oil temperature is not equal to or higher than the predetermined temperature, there is a possibility that the predetermined amount of oil cannot be filled before the engine complete explosion due to the viscous resistance of the oil. In addition, when the oil temperature is high, the volumetric efficiency of the oil pump 8 decreases due to a decrease in viscous resistance, and the amount of leakage at each part of the valve increases. This is because there is a possibility that cannot be filled.

  Next, when the brake is released, it is determined that the driver is willing to start the engine, and even when the brake is stepped on, when it is confirmed that the idle stop switch is not energized, It is determined that the driver is willing to start the engine. This is because, for example, when the driver feels that the temperature in the passenger compartment is hot, the battery will be overloaded and the air conditioner cannot be used when the engine is stopped due to idle stop. Thus, the idle stop control can be canceled by the control so that the control more in line with the driver's intention can be executed.

  When it is determined that the driver intends to start the engine, the engine is restarted by operating the starter motor 19a.

  Since the oil pump 8 is in a stopped state when the engine is stopped, the oil supplied to the forward clutch 25 and the pulley cylinder chambers 33 and 37 of the CVT 3 also escapes from the oil passage and the hydraulic pressure decreases. For this reason, when the engine is restarted, the forward clutch 25 is also in a state of being disengaged, so it is necessary to supply hydraulic pressure when the engine is restarted. The oil stored in the pulley cylinder chambers 33 and 37 does not come out so much when the idle stop time is short, and a certain amount of oil is secured. When the vehicle is stopped for a long time, the oil gradually comes out. It is configured as follows.

[Engine restart control]
Next, forward clutch engagement control will be described. Basically, when the forward clutch 25 is engaged, the state until the clutch piston stroke ends by crushing the backlash or the disc spring of the clutch plate is defined as the precharge phase. It is defined as the fastening phase. A state where the clutch plate slip state is still not resolved after the engagement phase is finished is defined as an engagement end phase, and a state where the clutch plate slip is resolved and a transition to complete engagement is defined as a complete engagement phase.

[Engine restart control processing]
FIG. 4 is a flowchart showing a flow of engine restart control executed in the idle stop control unit 17. Hereinafter, each step S will be described.

  In step S200, it is determined whether or not the select position is the travel range. If YES, the process proceeds to step S220, and if NO, the process proceeds to step S210.

<Starter motor drive control processing>
Steps S240 to S242 show the flow of starter motor drive control processing.

  In step S240, it is determined whether or not the engine has completely exploded. If YES, the process proceeds to step S242, and if NO, the process proceeds to step S241. The complete explosion determination is not particularly limited as long as it is determined whether the engine speed is equal to or higher than a predetermined speed.

  In step S241, the starter motor is driven, and the process returns to step S240.

  In step S242, the starter motor is stopped and the control is terminated.

<Forward clutch engagement state judgment control process>
Steps S220 to S218 show the flow of control processing for determining whether the engaged state of the forward clutch 25 corresponds to the precharge phase, the engaged phase, or the engaged end phase.

  In step S210, the select switching solenoid 70 is turned on and the control is terminated.

<Torque down control processing>
Steps S220 to S234 show the flow of the engine torque down control process according to the engaged state of the forward clutch.

  In step S220, the select switching solenoid 70 is turned on, and the process proceeds to step S221.

  In step S221, time measurement from the engine start is started by the phase timer, and the process proceeds to step S222.

(Precharge phase)
In step S222, the forward clutch engagement pressure command value Pcc is set to the engagement command value Ppre in the precharge phase, and the process proceeds to step S223.

  In step S223, the torque-down command value TD is set as the torque-down command value Tdpre in the precharge phase, and the process proceeds to step S224.

  In step S224, it is determined whether or not the precharge phase time Tp has elapsed. If YES, the process proceeds to step S225 to execute torque reduction control in the engagement phase, and if NO, the process returns to step S222.

(Conclusion phase)
In step S225, the forward clutch engagement pressure command value Pcc is set to a pressure P (Vp) at which the shelf pressure advancement speed becomes Vp, and the process proceeds to step S226.

  In step S226, the torque-down command value TD is set as the torque-down command value TDs in the engagement phase, and the process proceeds to step S227.

  In step S227, it is determined whether the engagement phase time Ts has elapsed. If YES, the process proceeds to slip determination in step S228, and if NO, the process returns to step S225.

(Forward clutch slip judgment and slip reduction control in the engagement phase)
In step S228, the rotational speed difference SLIP between the turbine shaft 1a and the transmission input shaft 1b is calculated, and the process proceeds to step S229.

  In step S229, it is determined whether or not the rotational speed difference SLIP calculated in step S228 exceeds a predetermined value. If YES, the process proceeds to step S230, and if NO, the process proceeds to step S231.

  In step S230, the torque-down command value TD is set to TDL (SLIP) larger than the torque-down amount TDs in the engagement phase to eliminate the slip of the forward clutch 25, and the process proceeds to step S231. The setting of TDL (SLIP) reads a value corresponding to SLIP calculated in step S208 based on the SLIP-TDL (SLIP) map shown in FIG.

  In step S231, the forward clutch engagement pressure command value Pcc is set as the engagement command value Pend in the engagement end phase, and step S232 is set.

  In step S232, it is determined whether the rotational speed difference SLIP is 0. If YES, the process proceeds to step S233, and if NO, the process returns to step S228.

(Conclusion end phase)
In step S233, the select switching solenoid 70 is turned OFF, and the process proceeds to step S234.

  In step S234, the torque-down command value TD is gradually released and the control is terminated.

[Operation of forward clutch engagement processing and torque down amount setting processing]
Next, the operation based on the flowchart will be described. When the engine restart command is output, the starter motor 19a is driven in step S240 to step S242, and the engine 19 is started. In parallel with this operation, it is determined whether or not the accelerator pedal is ON.

  If the accelerator pedal is not depressed, a large torque is not output because the engine 19 maintains the idling speed. Therefore, the process proceeds from the precharge phase based on normal timer management to the engagement phase → the engagement end phase, and the forward clutch 25 is engaged.

  On the other hand, when the accelerator pedal is depressed, the engine output torque increases according to the accelerator opening. Here, when the hydraulic pressure necessary for engaging the forward clutch 25 is not sufficiently secured, the forward clutch slip state does not continue for a long time when the input torque from the engine 19 increases, and the clutch plate is deteriorated or the start response is increased. Incurs a delay.

  Therefore, when the accelerator pedal is depressed, the torque reduction amount TD is output to the engine control unit 18 to limit the input torque to the forward clutch 25. Hereinafter, the torque down amount setting logic will be described.

[Torque down amount setting]
In the automatic transmission according to the first embodiment, the output torque of the engine output shaft 19b is amplified by the torque converter 1 and drives the transmission input shaft 1b. Here, the input torque control to the forward clutch 25 is achieved by controlling the torque of the turbine shaft 1a. Since the turbine torque Tt is determined by the engagement capacity of the forward clutch 25, the turbine torque Tt (Pcc) is estimated from the engagement pressure command value to the forward clutch 25.

FIG. 7 is a diagram illustrating the relationship between the speed ratio e and the torque ratio t in the torque converter 1. Here, if the turbine speed is Nt, the engine speed is Ne, the turbine torque is Tt, and the engine torque is Te, the speed ratio e = Nt / Ne Torque ratio t = Tt / Te
Therefore, the target engine torque Te * that outputs the turbine torque Tt is
Te * = (1 / t) ・ Tt (Pcc)
It becomes.

  Here, when the engine is restarted in a state where the forward clutch 25 is not engaged, since the inertia applied to the turbine shaft 1a is only its own inertia, the turbine shaft 1a is rotated by the engine output, and the turbine rotational speed Nt increases. Resulting in. If the speed ratio e is calculated as the ratio between the engine speed Ne and the turbine speed Nt in this state, the speed ratio e becomes a very large value, and accordingly, the torque ratio t becomes a small value.

  That is, as the target engine torque Te * with respect to the turbine torque Tt increases, the torque reduction amount also decreases, and the engine feels like being blown up. Therefore, in the torque-down control amount calculation process of the first embodiment, the torque-down amount is calculated using the primary rotation speed Npri instead of the turbine rotation speed Nt. Since the primary rotational speed Npri is a value dependent on the vehicle load, an accurate torque reduction amount can be calculated. Hereinafter, torque down amount setting control processing based on the above logic will be described.

[Torque down amount setting control processing]
FIG. 6 is a flowchart showing the flow of torque down amount setting control processing.
In step S401, the engine speed Ne and the primary speed Npri are read.

  In step S402, the speed ratio e = Npri / Ne is read.

  In step S403, the torque ratio t (= Tt / Te) is read from the speed ratio-torque ratio map shown in FIG.

  In step S404, a turbine torque estimated value Tt (Pcc) corresponding to the forward clutch engagement pressure command value Pcc is calculated.

  In step S405, the estimated turbine torque value Tt (Pcc) in each phase is read, the target engine torque Te * is calculated based on the estimated turbine torque value Tt (Pcc) and the torque ratio t, and is output to the engine control unit 18. . The torque ratio t is determined by the characteristics of the torque converter 1, and the turbine torque estimated value Tt (Pcc) can also be determined from the forward clutch engagement pressure command value Pcc. Therefore, the target engine torque Te * can be calculated from the speed ratio e. it can. The torque-down amount is set so that the target engine torque Te * becomes an optimum input torque in each phase in the forward clutch engagement control.

  In step S406, the difference Te-Te * between the actual engine torque Te and the target engine torque Te * is calculated, and the engine torque-down control is performed using the difference Te-Te * as the torque-down amount TD.

[Change over time in torque-down control when the reference time Ts is exceeded]
FIG. 8 is a time chart showing the change over time of the torque-down control when the time of the engagement phase exceeds the reference time Ts.

(Time t1)
The brake is turned off by the driver at time t1, the supply of hydraulic oil to the forward clutch 25 is started to prepare for restart, and a precharge phase in which the clutch plate is loosened, that is, a piston stroke is started.

(Time t1 to t2)
At time t1 to t2, the accelerator is turned on, and immediately after that, the secondary pulley pressure starts to rise. At this time, the forward clutch 25 is in the precharge phase, and even if the engine torque Te is input, the torque transmission is hardly performed. Therefore, the engine torque Te is suppressed by the torque down control and does not increase.

(Time t2)
At time t2, the actual pressure in the piston chamber of the forward clutch 25 starts to rise. At this time, the hydraulic pressure of the secondary pulley continues to rise.

(Time t2 to t3)
At times t2 to t3, the actual pressure of the forward clutch 25 starts to rise, but does not reach the command pressure. Until the time t3, the precharge phase continues, so the engine torque does not increase. On the other hand, the secondary pulley pressure reaches the target pressure and becomes a constant pressure, and the constant pressure is continued thereafter.

(Time t3)
At time t3, the piston stroke of the forward clutch 25 ends and the clutch phase shifts to an engagement phase where the clutch plate starts to slip. Accordingly, the actual pressure of the forward clutch 25 reaches the command pressure, and the transmittable torque of the forward clutch 25 starts to increase. By shifting to the engagement phase, a torque-down command corresponding to the engagement phase is output by torque-down control, and the torque-down amount of the engine starts to rise while being suppressed so as not to exceed the transmittable torque of the forward clutch 25.

(Time t4)
At time t4, the measurement time from the start of the fastening phase reaches the reference time Ts. However, the slip of the clutch plate has not yet been resolved, and the shift to the engagement end phase is made without shifting to the complete engagement. In order to quickly eliminate the clutch plate slip, the torque reduction amount of the engine is increased in the engagement end phase at times t4 to t5, and is larger than the torque reduction amount in the engagement phase at times t3 to t4. As a result, the engine torque Te decreases, and the difference ΔN between the turbine rotational speed Nt, that is, the drive-side rotational speed of the forward clutch 25, and the primary rotational speed Ni, that is, the output-side rotational speed of the forward clutch 25 gradually decreases, and the clutch plate slips. Gradually disappears.

(Time t5)
At time t5, the clutch plate slip is eliminated, and the phase shifts to a complete engagement phase in which the forward clutch 25 can be completely engaged. The command pressure of the forward clutch 25 is used as a base pressure, the fastening pressure is used as the base pressure, and the engine torque down command is canceled.

(Time t6)
The engine torque becomes maximum at time t6.

[Effects of Example 1]
In the first embodiment, the engine torque is controlled so as not to exceed the engagement capacity of the forward clutch 25 during the restart after the idle stop, and the turbine rotational speed Nt and the transmission input shaft rotation after the engagement phase of the forward clutch 25 ends. When the difference from the number Npri is equal to or greater than a predetermined value, the subsequent torque down amount TDL (SLIP) is assumed to be larger than the torque down amount TDs in the engagement phase. Thus, even when the sufficient amount of oil cannot be ensured due to deterioration over time when the engine is restarted after idling stop, it is possible to make it possible to restart without a sense of incongruity.

  Further, when the engine torque-down amount TDL (SLIP) in the engagement end phase is equal to or greater than the torque-down amount TDs at the end of the engagement phase, the difference in the rotational speed between the drive plate and the driven-side clutch plate of the forward clutch 25, that is, the turbine The difference ΔN between the rotational speed Nt and the primary rotational speed Ni is calculated, and the torque-down amount TDL (SLIP) is gradually increased based on the rotational speed difference ΔN. As a result, even when the forward clutch 25 slips after the engagement phase ends, the clutch plate slip is gradually eliminated, thereby making it possible to avoid sudden clutch engagement and perform a smooth start.

  The lockup solenoid 71, the select switching solenoid 70, the select switching valve 75 and the select control valve 90, which are means capable of adjusting the pressure only in the low pressure region, perform engine restart fastening pressure control and are higher than the low pressure region after the fastening is completed. A clutch regulator valve 45, a pressure modifier valve 73, and a line pressure solenoid 72, which are second engagement pressure means capable of adjusting pressure only in the high pressure region, are provided, and after the forward clutch 25 is completely engaged, the engagement pressure control by the clutch regulator valve 45 is performed. Switch to. At that time, the torque-down amount was gradually decreased, and the torque-down was canceled after the engine torque reached a certain amount. As a result, engine torque is not suddenly input, and belt slippage of the belt type continuously variable transmission can be prevented.

(Other examples)
As described above, the best mode for carrying out the present invention has been described based on the first embodiment. However, the specific configuration of the present invention is not limited to each embodiment, and does not depart from the gist of the present invention. Such design changes are included in the present invention.

It is a figure showing the control system of the automatic transmission provided with the belt-type continuously variable transmission. It is a circuit diagram showing the hydraulic circuit of a belt type continuously variable transmission. It is a flowchart showing the basic control content of idle stop control. It is a flowchart which shows the flow of engine restart control. It is a SLIP-TDL (SLIP) map. It is a flowchart which shows the flow of a torque down amount setting control process. It is a figure which shows the relationship between the speed ratio and torque ratio in a torque converter. 6 is a time chart showing a change with time of torque-down control when the engagement phase time exceeds a reference time Ts. It is a time chart which shows the time-dependent change of the slip confirmation torque down cancellation | release control in a fastening phase.

Explanation of symbols

3 Belt type continuously variable transmission 4 Primary rotational speed sensor 5 Secondary rotational speed sensor 6 Hydraulic control valve unit 8 Oil pump 9 Control unit 10 Engine 13 Idle stop switch 16 Line pressure sensor 17 Idle stop control unit 18 Engine control unit 19 Engine 19b Engine output shaft 25 Forward clutch 33 Primary pulley cylinder chamber 40 Pressure regulator valve 45 Clutch regulator valve 50 Pilot valve 70 Select switching solenoid 71 Lockup solenoid 72 Line pressure solenoid 73 Pressure modifier valve 75 Select switching valve 83 Pressure modifier valve 90 Select Control valve

Claims (2)

An oil pump driven by an engine;
A starting clutch fastened by a fastening pressure using the oil pump as a hydraulic source when the vehicle starts,
An engagement pressure control means for performing an engagement pressure control through an engagement phase when shifting from the released state of the starting clutch to the engaged state;
An idle stop control means for stopping the engine when the vehicle is stopped and when a predetermined condition is satisfied, and restarting the engine when the predetermined condition is not satisfied;
In an automatic transmission control device comprising:
The engagement pressure control means outputs an engine torque down command to the engine control unit so as not to exceed the engagement capacity of the start clutch in the engagement phase.
When the difference between the turbine rotational speed after the end of the engagement phase and the transmission input shaft rotational speed is equal to or greater than a predetermined value, an engine torque down command for outputting a subsequent engine torque limit amount equal to or greater than the predetermined value is output. Automatic transmission control device. The control apparatus for an automatic transmission according to claim 1,
The fastening pressure control means calculates a rotational speed difference between the driving side and the driven side of the start clutch when the torque limit amount of the engine is greater than or equal to the predetermined value, and gradually increases the engine based on the rotational speed difference. A control device for an automatic transmission, wherein a torque down command for increasing a torque limit amount is output to an engine control unit.

Images