JP4063002B2 - Control device for power transmission mechanism for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for a vehicle power transmission mechanism, and more particularly to control when engaging or releasing an interrupting device that connects and disconnects power transmission.
[0002]
[Prior art]
(a) a power transmission mechanism including an intermittent device that transmits power by being frictionally engaged; and (b) a stop that reduces power transmission by reducing the engagement load of the intermittent device when the vehicle stops. There is known a control device for a vehicle power transmission mechanism having a time neutral means. The device described in Japanese Patent Laid-Open No. 5-79562 is an example, and when a predetermined neutral control execution condition is satisfied, the hydraulic pressure (engagement load) is reduced at a stroke until the forward clutch (interrupting device) starts to slide. After that, by gradually lowering the hydraulic pressure and releasing the forward clutch, the neutral state is achieved as quickly as possible while suppressing shocks such as fluctuations in driving force associated with clutch release. Further, according to the neutral control at the time of stopping, the engine load is reduced and the fuel efficiency is improved, and the creep force can be appropriately controlled.
[0003]
[Problems to be solved by the invention]
  However, in the conventional neutral control at the time of stopping, since the hydraulic pressure of the interrupting device is reduced to a predetermined value at a stretch, individual differences such as variations in μ (friction coefficient) of the friction material of the interrupting device, Due to the change, there is a possibility that a shock will occur when releasing to a predetermined slip state or the time until release (time lag) may be longer.It was.
[0004]
  The present invention has been made in the background of the above circumstances, the purpose of which is, regardless of individual differences or changes over time, such as variations in μ of the intermittent device,Prevents the occurrence of a shock or a long time to release when releasing to a predetermined slip state with neutral control when the vehicle is stoppedThere is.
[0005]
[Means for Solving the Problems]
  In order to achieve such an object, the first invention provides (a) an interrupting device for transmitting power by frictional engagement.A fluid-type power transmission device that is provided between the intermittent device and the driving force source and transmits power via a fluid;A power transmission mechanism comprising: (b) slipping by reducing the engagement load of the intermittent device when the vehicle is stopped.In addition, by feedback controlling the engagement load of the intermittent device so that the speed ratio or speed difference of the input / output rotation of the fluid power transmission device becomes a predetermined value,A control device for a vehicle power transmission mechanism having a neutral means for stopping to reduce power transmission, and (c)While comprising learning means for storing the feedback-controlled engagement load as a slip engagement load, (d) The neutral means at the time of stopping obtains an engagement load immediately before slipping immediately before the intermittent device slips based on the slip engagement load, and performs a first sweep control of the engagement load of the intermittent device to the engagement load immediately before the slip. When the engagement load immediately before the slip is reached, the slip is started by slowing down the lowering speed by the second sweep control. The engagement load immediately before the slip is determined by the oil temperature and the input. It is obtained by adding a predetermined value to the slip engagement load so that the higher the oil temperature and the higher the input torque estimation value, the torque estimation value is used as a parameter.It is characterized by that.
[0008]
  First2Invention is the firstMysteriousIn a control device for a vehicle power transmission mechanism, the intermittent device is engaged based on the slip engagement load when the intermittent device is switched from a disconnected state to a driven state by engaging the intermittent device. A switching engagement control means for controlling the engagement load at the time of transition is provided.
[0010]
【The invention's effect】
  In such a vehicle power transmission mechanism control device,Since the engagement load of the interrupting device is feedback controlled by the neutral means when the vehicle stops so that the speed ratio or speed difference of input / output rotation of the fluid power transmission device becomes a predetermined value, each part such as μ variation of the interrupting device Regardless of individual differences or changes over time, the intermittent device is always in a predetermined slip state, the engine load is reduced, the fuel consumption is improved, and the creep force is appropriately controlled. In addition, since the engagement load subjected to the feedback control is stored as the slip engagement load, it is easy to set the slip engagement load to be in a predetermined slip state as compared with the feedforward control or the like.
[0011]
  stopVehicle neutral meansAlso, aboveBased on the slip engagement load, the engagement load immediately before the slippage of the interrupting device is obtained, and the engagement load of the interrupting device is obtained up to the engagement load immediately before the slip.Large change rate due to the first sweep controlAfter reducing quickly,By the second sweep controlSince slip is started by slowing down the reduction speed, a neutral state can be quickly achieved while suppressing shocks such as fluctuations in driving force accompanying the release (slip) of the intermittent device. In this case, since the slip engagement load is an engagement load that brings the intermittent device into a predetermined slip state regardless of individual differences of each part such as variations in μ of the intermittent device or changes with time, the slip engagement load The engagement load just before the slip determined based on the above is also an appropriate value regardless of individual differences and changes over time of each part, and the sudden load until the engagement load reaches the engagement load immediately before slip due to individual differences and changes over time. When a change occurs, the intermittent device starts to release (slip) and a shock occurs. Conversely, the time to start releasing (slip) is delayed and the time until the neutral state is reached (time lag) may increase. Is prevented.
[0012]
  First2The invention relates to a case where the engagement load at the transition transition of the intermittent device is controlled by the switching engagement control means at the time of drive switching from the shut-off state to the drive state, and the engagement load at that time is used as the slip engagement load. Because it is based on control, it is possible to control the engagement appropriately regardless of individual differences such as variations in μ of the intermittent device and changes over time.For example, the drive state can be achieved quickly while suppressing the engagement shock. can do.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a vehicle having a fluid power transmission device that includes an engine such as an internal combustion engine that generates power by combustion of fuel as a driving power source for traveling and that transmits the output of the engine via a fluid. Although preferably applied, the present invention can also be applied to a hybrid vehicle including another driving force source such as an electric motor. As the fluid type power transmission device, a torque converter having a torque amplifying action is preferably used, but other fluid type power transmission devices such as a fluid coupling can also be adopted.
[0014]
As the interrupting device, a hydraulic friction engagement device that is frictionally engaged by a hydraulic cylinder such as a clutch or a brake is preferably used. However, the interrupting device is always held in a connected state (engaged state) by a diaphragm spring and the clutch release. A single-plate start clutch that is blocked (released) by a cylinder, or an electromagnetic friction engagement device that is frictionally engaged by the action of electromagnetic force may be used.
[0015]
The power transmission mechanism is, for example, a planetary gear type forward / reverse switching device, and a switching state of a rotating element is switched by an interrupting device such as a clutch or a brake so that a power transmission is interrupted, and a forward traveling capable of traveling forward is possible. The drive state and the reverse drive state in which reverse travel is possible are established. The power transmission mechanism may be an automatic transmission having a plurality of planetary gear units and a plurality of clutches and brakes (interrupting / disconnecting devices) and capable of establishing a plurality of forward shift stages having different gear ratios. Various modes are possible, for example, the power transmission may be connected or cut off by the neutral means, and the neutral means at the time of stopping may perform slip control of the intermittent device that can cut off the power transmission.
[0016]
The slip control of the intermittent device by the neutral means when the vehicle is stopped is an engagement load control device such as a solenoid valve or a linear solenoid valve capable of continuously changing the engagement hydraulic pressure (engagement load) by, for example, duty control of the excitation current. It is done using.
[0019]
  First2The invention relates to drive switching that engages the interrupting device to switch from the shut-off state to the drive state.FirstIn carrying out the invention, at the time of non-drive switching that releases the interrupting device and switches from the drive state to the shut-off state, the engagement load during the release transition of the interrupting device is controlled based on the slip engagement load, or the interrupting device The engagement load at the time of engagement transition or release transition of the intermittent device is controlled based on the slip engagement load at the time of shifting to switch to a gear stage having a different gear ratio by engaging or releasing Are possible.
[0020]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a skeleton diagram of a vehicle drive device 10 to which the present invention is applied. This vehicle drive device 10 is of a horizontal type and is suitably employed in an FF (front engine / front drive) type vehicle, and includes an engine 12 as a driving force source for traveling. The output of the engine 12 composed of an internal combustion engine is differentially transmitted from a torque converter 14 as a fluid power transmission device through a forward / reverse switching device 16, a belt type continuously variable transmission (CVT) 18, and a reduction gear 20. It is transmitted to the gear device 22 and distributed to the left and right drive wheels 24L, 24R.
[0021]
The torque converter 14 includes a pump impeller 14p connected to the crankshaft of the engine 12 and a turbine impeller 14t connected to the forward / reverse switching device 16 via a turbine shaft 34, and transmits power through a fluid. Is supposed to do. Further, a lock-up clutch 26 is provided between the pump impeller 14p and the turbine impeller 14t, and the engagement side oil chamber and the release side are provided by a switching valve of a hydraulic control circuit 86 (see FIG. 2). By switching the hydraulic pressure supply to the oil chamber, it is engaged or released, and the pump impeller 14p and the turbine impeller 14t are integrally rotated by being completely engaged. The pump impeller 14p includes a mechanical oil pump 28 that generates hydraulic pressure for controlling the shift of the belt-type continuously variable transmission 18, generating belt clamping pressure, or supplying lubricating oil to each portion. Is provided.
[0022]
The forward / reverse switching device 16 is mainly composed of a double pinion type planetary gear device, and the turbine shaft 34 of the torque converter 14 is integrally connected to the sun gear 16 s, and the input shaft 36 of the belt type continuously variable transmission 18. Is integrally connected to the carrier 16c, while the carrier 16c and the sun gear 16s are selectively connected via the forward clutch C1, and the ring gear 16r is selectively fixed to the housing via the reverse brake B1. It is like that. The forward clutch C1 and the reverse brake B1 correspond to an interrupting device, both of which are hydraulic friction engagement devices that are frictionally engaged by a hydraulic cylinder. The forward clutch C1 is engaged and the reverse brake When B1 is released, the forward / reverse switching device 16 enters a driving state for forward traveling and is integrally rotated, and the driving force in the forward direction is transmitted to the belt-type continuously variable transmission 18 side. When the brake B1 is engaged and the forward clutch C1 is disengaged, the forward / reverse switching device 16 is in a drive state for reverse travel, and the input shaft 36 rotates in the reverse direction with respect to the turbine shaft 34. As a result, the driving force in the reverse direction is transmitted to the belt type continuously variable transmission 18 side. When both the forward clutch C1 and the reverse brake B1 are released, the forward / reverse switching device 16 enters a shut-off state (neutral) that cuts off power transmission. In the present embodiment, the forward / reverse switching device 16 corresponds to a power transmission mechanism.
[0023]
The forward clutch C1 and the reverse brake B1 are engaged and released when the manual valve 120 (see FIG. 3) of the hydraulic control circuit 86 is mechanically switched according to the operation of the shift lever 77. Yes. The shift lever 77 is operated to the “P” position for parking, the “R” position for reverse travel, the “N” position for interrupting power transmission, the “D” position and “L” position for forward travel. In the “P” position and the “N” position, the hydraulic oil in the forward clutch C1 and the reverse brake B1 are both drained from the manual valve 120 and released together. In the “R” position, the hydraulic oil adjusted to the modulator hydraulic pressure PM by the modulator valve 122 is supplied from the manual valve 120 to the reverse brake B1 and engaged therewith, and the hydraulic oil in the forward clutch C1 is supplied to the manual valve. Drained from 120 and released. Further, in the “D” position and the “L” position, the hydraulic oil adjusted to the modulator hydraulic pressure PM is supplied from the manual valve 120 to the forward clutch C1 and engaged, and the hydraulic oil in the reverse brake B1 is engaged. Is drained from the manual valve 120 and released.
[0024]
Returning to FIG. 1, the belt-type continuously variable transmission 18 includes an input-side variable pulley 42 having a variable effective diameter provided on the input shaft 36 and an output-side variable having a variable effective diameter provided on the output shaft 44. A pulley 46 and a transmission belt 48 wound around the variable pulleys 42 and 46 are provided, and power is transmitted through a frictional force between the variable pulleys 42 and 46 and the transmission belt 48. The variable pulleys 42 and 46 each have a variable V-groove width and are configured to include a hydraulic cylinder. The hydraulic pressure of the hydraulic cylinder of the input-side variable pulley 42 is controlled by a hydraulic control circuit 86, so that both variable pulleys 42. , 46 is changed to change the engagement diameter (effective diameter) of the transmission belt 48, and the gear ratio γ (= input shaft rotational speed NIN / output shaft rotational speed NOUT) is continuously changed. Further, the hydraulic pressure of the hydraulic cylinder of the output side variable pulley 46 is regulated by a hydraulic control circuit 86 so that the transmission belt 48 does not slip.
[0025]
FIG. 2 is a block diagram for explaining a control system provided in the vehicle for controlling the engine 12, the belt type continuously variable transmission 18, and the like of FIG. 1. The electronic controller 60 includes an engine rotation speed sensor 62. , Turbine rotational speed sensor 64, input shaft rotational speed sensor 65, vehicle speed sensor 66, throttle sensor 68 with idle switch, cooling water temperature sensor 70, oil temperature sensor 72, accelerator operation amount sensor 74, foot brake switch 76, lever position sensor 78 Are connected, and the rotational speed of the engine 12 (engine rotational speed) NE, the rotational speed of the turbine shaft 34 (turbine rotational speed) NT, the rotational speed of the input shaft 36 (input shaft rotational speed) NIN, the vehicle speed V, and the electronic throttle valve 80 fully closed state (idle state) and its opening (throttle valve opening) θ_TH, Cooling water temperature T of engine 12_WThe oil temperature T of the hydraulic control circuit 86 of the belt type continuously variable transmission 18 or the like_OIL, Operation amount (accelerator operation amount) Acc of an accelerator operation member such as an accelerator pedal, presence / absence of operation of a foot brake as a service brake, lever position (operation position) P of the shift lever 77_SH, Etc. are supplied. The turbine rotational speed NT coincides with the input shaft rotational speed NIN during forward traveling with the forward clutch C1 engaged, and the vehicle speed V is the rotational speed of the output shaft 44 of the belt-type continuously variable transmission 18 (output shaft rotational speed). Speed) corresponds to NOUT. The accelerator operation amount Acc represents the driver's requested output amount.
[0026]
The electronic control unit 60 includes a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM, and performs signal processing according to a program stored in the ROM in advance. By performing the processing, output control of the engine 12, shift control of the belt-type continuously variable transmission 18, belt clamping pressure control, engagement and release control of the lock-up clutch 26, and the like are executed. Depending on the situation, the engine control and the shift control are divided. The output control of the engine 12 is performed by an electronic throttle valve 80, a fuel injection device 82, an ignition device 84, etc., and the shift control of the belt type continuously variable transmission 18, the belt clamping pressure control, and the engagement and release of the lockup clutch 26. All the controls are performed by a hydraulic control circuit 86. The hydraulic control circuit 86 is a solenoid valve that opens and closes the oil passage when excited by the electronic control device 60, a linear solenoid valve that performs hydraulic control, and opens and closes the oil passage according to the signal pressure output from these solenoid valves. It includes an on-off valve, a pressure regulating valve, and the like.
[0027]
FIG. 3 is a hydraulic circuit diagram of a portion related to the engagement and release control of the forward clutch C1 and the reverse brake B1 in the hydraulic control circuit 86. In addition to the manual valve 120, a garage shift control valve 112, a garage shift valve 114 are shown. It has. The garage shift control valve 112 includes a spool 112a that can move in the axial direction and a spring 112b as a biasing means that biases the spool 112a in one direction, and is a linear solenoid valve SLT that is duty-controlled by the electronic control unit 60. With the output hydraulic pressure as the pilot pressure, the modulator hydraulic pressure PM is continuously regulated to output the garage shift hydraulic pressure PG. The garage shift hydraulic pressure PG advances through the garage shift valve 114 and the manual valve 120. By being supplied to the clutch C1, the engagement transient hydraulic pressure of the forward clutch C1 and the like are controlled.
[0028]
The garage shift valve 114 includes a spool 114a movable in the axial direction and a spring 114b as a biasing unit that biases the spool 114a to one side. In a normal “D” position, the electronic control unit 60 controls a solenoid. When both the valve SL and DSU are excited and signal pressure is output, the modulator hydraulic pressure PM is output to the manual valve 120 side as it is held in the OFF state shown in the right half of the figure. The clutch C1 is held in the engaged state. Even in the “R” position, the garage shift valve 114 is in the OFF state shown in the right half of the figure, and the modulator hydraulic pressure PM is output to the manual valve 120 side as it is, and the reverse brake B1 is engaged by the modulator hydraulic pressure PM. Kept in a state.
[0029]
On the other hand, when the shift lever 77 is operated from the “N” position to the “D” position (N → D shift), only the solenoid valve SL is energized and the solenoid valve DSU is de-energized. The shift valve 114 is in the ON state shown in the left half of the figure, and outputs the garage shift hydraulic pressure PG output from the garage shift control valve 112 to the manual valve 120 side. The garage shift hydraulic pressure PG is adjusted according to the output hydraulic pressure of the linear solenoid valve SLT, and the forward clutch C1 is smoothly engaged by the pressure control of the garage shift hydraulic pressure PG. Further, when the vehicle is stopped at the “D” position and the predetermined neutral control execution condition is satisfied, the solenoid valve DSU is de-energized in the same manner as in the N → D shift, so that the left half of FIG. When the garage shift hydraulic pressure PG output from the garage shift control valve 112 is output to the manual valve 120 side, the garage shift hydraulic pressure PG is adjusted according to the output hydraulic pressure of the linear solenoid valve SLT. The clutch C1 is brought into a predetermined slip state to reduce power transmission. The linear solenoid valve SLT and the garage shift control valve 112 function as a garage shift hydraulic pressure PG that is an engagement hydraulic pressure of the forward clutch C1, that is, an engagement load control device that controls the engagement load. The N → D shift is a drive switch for switching the forward / reverse switching device 16 from the shut-off state to the drive state. Even in the “R” position for reverse travel, the reverse brake B1 is used when the reverse brake B1 is smoothly engaged by the garage shift hydraulic pressure PG during N → R shift or when a predetermined neutral control execution condition is satisfied. Can be brought into a slip state.
[0030]
FIG. 4 shows the various functions executed by the signal processing of the electronic control unit 60 when the vehicle stops when the forward clutch C1 is in a predetermined slip state when the vehicle is stopped in the “D” position, that is, the forward drive state. FIG. 2 is a block diagram for explaining a portion related to neutral control and control of the engagement transient hydraulic pressure (garage shift hydraulic pressure PG) of the forward clutch C1 at the time of garage shift (drive switching), and functionally neutral means 100 at the time of stopping, learning Means 106 and switching engagement control means 108 are provided, and the neutral means 100 at stop includes sweep means 102 and feedback control means 104.
[0031]
FIG. 5 is a flowchart for explaining the specific processing contents of the neutral means 100 at the time of stopping and the learning means 106. Steps S2 to S4 are executed by the sweep means 102, and steps S5 to S7 are executed by the feedback control means 104. Steps S8 and S9 are executed by the learning means 106. FIG. 6 is an example of a time chart showing changes of each part when neutral control at the time of stop is performed according to the flowchart of FIG.
[0032]
In step S1 of FIG. 5, it is determined whether or not the neutral control execution start condition is satisfied, specifically, for example, when the forward / reverse switching device 16 is in the driving state for forward travel, the vehicle speed V is substantially 0, and the foot It is determined whether the brake has been depressed and whether or not that state has continued for a predetermined time (for example, about several seconds). Whether or not the drive state is for forward travel is determined by, for example, the operation position P of the shift lever 77._SHCan be determined by whether or not the forward travel position is “D” or “L”. When the stop neutral control execution start condition is satisfied, the stop neutral control in step S2 and subsequent steps is executed. Time t in FIG.₁Is the time when the foot brake is depressed and the vehicle speed V becomes 0 when traveling in the “D” or “L” position, and the time t₂Is the time when the determination in step S1 is YES (affirmed) after a predetermined time has elapsed.
[0033]
In step S2, the solenoid valve DSU is first de-energized and the garage shift valve 114 is turned on as shown in the left half of FIG. 3, and the garage shift hydraulic pressure PG output from the garage shift control valve 112 advances through the manual valve 120. So as to be supplied to the clutch C1. Thereafter, a predetermined value pc1sw2 is added to the slip hydraulic pressure learning value gpc1fb to obtain a hydraulic pressure command value immediately before slip (gpc1fb + pc1sw2), and the hydraulic pressure command value pc1 is rapidly decreased to a hydraulic pressure command value immediately before the slip (gpc1fb + pc1sw2) with a relatively large change rate. The first sweep control is performed. In the linear solenoid valve SLT, the duty ratio DSLT of the excitation current is controlled according to the hydraulic pressure command value pc1, and the garage shift hydraulic pressure PG is changed according to the hydraulic pressure command value pc1. The slip hydraulic pressure learning value gpc1fb is stored in the storage device 88 (see FIG. 2) in step S9 during feedback control, and is a slip engagement load at which the forward clutch C1 enters a predetermined slip state. The hydraulic pressure command value immediately before slip (gpc1fb + pc1sw2) is the engagement load immediately before slipping immediately before the forward clutch C1 slips, and the predetermined value pc1sw2 added to the slip hydraulic pressure learning value gpc1fb is that the forward clutch C1 slips. It is predetermined so as not to be stored in the storage device 88. Oil temperature T_OILIs high, the friction coefficient μ decreases and slipping easily occurs, and slipping easily occurs when the input torque is large. Therefore, the predetermined value pc1sw2 is equal to the oil temperature T_OILAnd the estimated input torque (such as the idling speed of the engine 12) as a parameter, the oil temperature T_OILIs set to be larger as the input torque is higher, and larger as the estimated input torque is larger. The change rate of the predetermined value pc1sw2 and the first sweep is determined so that the forward clutch C1 is not released (slipped) due to an undershoot of the garage shift hydraulic pressure PG.
[0034]
In step S3, it is determined whether or not the hydraulic pressure command value pc1 has decreased to a value lower than the hydraulic pressure command value immediately before slip (gpc1fb + pc1sw2). If pc1 <(gpc1fb + pc1sw2), the second sweep control is executed in step S4. Time t in FIG._ThreeIs the time when the hydraulic pressure command value pc1 reaches the hydraulic pressure command value immediately before slip (gpc1fb + pc1sw2) and the determination in step S3 is YES. In the second sweep control, the hydraulic pressure command value pc1 is slowly decreased at a relatively small change rate so that the driving force fluctuation (shock) accompanying the start of the slip of the forward clutch C1 is suppressed as much as possible, and the hydraulic pressure command value By controlling the duty ratio DSLT of the linear solenoid valve SLT according to pc1, the garage shift oil pressure PG is slowly lowered following the oil pressure command value pc1.
[0035]
In step S5, whether or not the forward clutch C1 has started to be released (slip) due to a decrease in the garage shift hydraulic pressure PG, for example, whether or not the turbine rotational speed NT has reached a predetermined value (for example, about 50 rpm) or more. When the release starts, the target rotational speed nttget is set in step S6, and the hydraulic pressure command value pc1, that is, the duty ratio DSLT is set so that the actual turbine rotational speed NT becomes the target rotational speed nttget in step S7. Feedback control. The target rotational speed nttget is set so that the speed ratio e (= NT / NE) of the torque converter 14 becomes a predetermined value K (for example, about 0.9) smaller than when the forward clutch C1 is completely released. Using the engine speed NE and the predetermined value K, the following equation (1) is obtained. As a result, the forward clutch C1 enters a predetermined slip state, and a predetermined creep is generated by power transmission in accordance with the slip state. Time t in FIG._FourIs the time when the turbine rotational speed NT is substantially matched with the target rotational speed nttget by feedback control.
nttget = NE × K (1)
[0036]
In step S8, whether or not the feedback control is in a stable state, for example, whether the deviation | nttget-NT | between the target rotational speed nttget and the turbine rotational speed NT is smaller than a predetermined value fberr (for example, about 20 to 30 rpm). If it is not stable, step S10 is executed. If it is stable, step S9 is executed, and the hydraulic pressure command value pc1 at that time is stored in the storage device 88 as the slip hydraulic pressure learning value gpc1fb ( Overwrite. In step S10, it is determined whether or not a stop neutral control end condition is satisfied, and step S7 and subsequent steps are repeated until the end condition is satisfied. Note that the learning in step S9 may be performed only once by a series of stopping neutral control.
[0037]
The termination condition of step S10 is whether or not the driver may start the vehicle. For example, when the foot brake is released or the accelerator pedal is depressed, or when the brake force ( When the end condition is satisfied, the return control in step S11 is executed. Time t in FIG._FiveIs the time when the end condition is satisfied. In the return control of step S11, the hydraulic pressure command value pc1, that is, the engagement of the hydraulic clutch command value pc1 so as to be engaged as quickly as possible while suppressing fluctuations in the driving force (shock) due to the sudden engagement of the forward clutch C1. By raising the garage shift hydraulic pressure PG at a predetermined rate of change, the forward clutch C1 is smoothly engaged. Since the forward clutch C1 is in the slip state, it can be quickly engaged in a short time while suppressing the shock, compared to a case where it is completely released by the neutral control.
[0038]
In step S12, for example, a deviation | NT−NIN | between the turbine rotational speed NT and the input shaft rotational speed NIN is determined in advance as to whether or not the engagement of the forward clutch C1 is completed due to the increase in the garage shift hydraulic pressure PG. Judgment is made based on whether or not the value has become smaller than a predetermined value (for example, about 50 rpm). Instead of the input shaft rotational speed NIN, a value obtained by multiplying the output shaft rotational speed NOUT by the speed ratio γ can be used. Then, when the engagement of the forward clutch C1 is completed, in step S13, the solenoid valve DSU is excited to place the garage shift valve 114 in the OFF state shown in the right half of FIG. 3, and the modulator hydraulic pressure PM is changed to the garage shift valve. An end process such as supplying the forward clutch C1 from 114 through the manual valve 120 is performed, and a series of stop-time neutral control is ended. Time t in FIG.₆Is the time when the engagement of the forward clutch C1 is completed and the determination in step S12 is YES.
[0039]
On the other hand, the engagement transition control during the garage shift by the switching engagement control means 108 executes signal processing according to the flowchart shown in FIG. In step R1 of FIG. 7, it is determined whether or not the shift lever 77 is operated from the “N” position to the “D” position based on the signal of the lever position sensor 78, ie, N → D shift, that is, drive switching. In the case of shift, step R2 and subsequent steps are executed. FIG. 8 is an example of a time chart showing changes in the hydraulic pressure command value pc1 and the rotational speeds NE and NT when the engagement transient hydraulic pressure of the forward clutch C1 is controlled according to the flowchart of FIG.₁Is the time when the N → D shift is performed and the determination in step R1 is YES.
[0040]
In step R2, first, the solenoid valve SL is energized with the solenoid valve DSU de-energized to turn the garage shift valve 114 to the ON state shown in the left half of FIG. 3, and the garage shift hydraulic pressure PG output from the garage shift control valve 112 is obtained. Is supplied to the forward clutch C1 via the manual valve 120. After that, fast fill control is performed in which the hydraulic pressure command value pc1, that is, the garage shift hydraulic pressure PG, is increased for a predetermined time α, and the hydraulic oil in the forward clutch C1 is quickly filled. In the first fill control, the piston of the hydraulic cylinder is rapidly advanced until immediately before the forward clutch C1 generates the engagement torque. The predetermined time α is an oil temperature T that affects the filling speed._OILFor example, oil temperature T_OILThe lower the is, the longer the time is set.
[0041]
In step R3, a constant pressure standby command value (gpc1fb + pc1st) is obtained by adding a predetermined value pc1st to the slip hydraulic pressure learned value gpc1fb stored in the neutral control at the time of stopping, and the hydraulic pressure command value pc1 is maintained at the constant pressure standby command value (gpc1fb + pc1st). The constant pressure standby control is performed. By controlling the duty ratio DSLT of the linear solenoid valve SLT in accordance with the hydraulic pressure command value pc1, the garage shift hydraulic pressure PG is controlled to a hydraulic pressure corresponding to the hydraulic pressure command value pc1, that is, the constant pressure standby command value (gpc1fb + pc1st). The constant pressure standby command value (gpc1fb + pc1st) is an engagement load that can engage the forward clutch C1 while suppressing fluctuation in driving force (shock) due to the sudden engagement of the forward clutch C1, and is a slip hydraulic pressure learning value gpc1fb. The predetermined value pc1st to be added to is predetermined and stored in the storage device 88 so that the forward clutch C1 starts to slip at least. Oil temperature T_OILIs high, the friction coefficient μ decreases and slipping easily occurs, and slipping easily occurs when the input torque is large. Therefore, the predetermined value pc1st is determined by the oil temperature T_OILAnd the estimated input torque (such as the idling speed of the engine 12) as a parameter, the oil temperature T_OILIs set to be larger as the input torque is higher, and larger as the estimated input torque is larger. Since the slip hydraulic pressure learning value gpc1fb is a slip engagement load at which the forward clutch C1 enters a predetermined slip state, the slip hydraulic pressure learning value gpc1fb can be used as it is as a constant pressure standby command value.
[0042]
In step R4, it is determined whether or not the forward clutch C1 has started engagement (slip), for example, a change in the turbine rotational speed NT, specifically, a reduction range from the maximum value NTmax after the start of control (NTmax−NT). Is determined to be greater than a predetermined value (for example, about 50 rpm) or the like, and when the engagement starts, the sweep control in step R5 is executed. Time t in FIG.₂Is the time when the forward clutch C1 starts to be engaged and the determination in step R4 becomes YES, and the sweep control in step R5 suppresses fluctuations in the driving force (shock) due to the sudden engagement of the forward clutch C1. The hydraulic clutch command value pc1, that is, the garage shift hydraulic pressure PG, is raised at a predetermined change rate so that the forward clutch C1 is smoothly engaged.
[0043]
In step R6, for example, a deviation | NT−NIN | between the turbine rotational speed NT and the input shaft rotational speed NIN is determined in advance as to whether or not the engagement of the forward clutch C1 is completed due to the increase in the garage shift hydraulic pressure PG. Judgment is made based on whether or not the value has become smaller than a predetermined value (for example, about 50 rpm). When the engagement of the forward clutch C1 is completed, in step R7, the solenoid valve DSU is excited to place the garage shift valve 114 in the OFF state shown in the right half of FIG. 3, and the modulator hydraulic pressure PM is changed to the garage shift valve. An end process such as supplying from 114 to the forward clutch C1 via the manual valve 120 is performed, and a series of garage shift control is ended. Time t in FIG._ThreeIs the time when the engagement of the forward clutch C1 is completed and the determination in step R6 is YES.
[0044]
In this way, in this embodiment, the neutral means 100 at the time of stopping feedback-controls the hydraulic pressure command value pc1 so that the speed ratio e of the torque converter 14 becomes the predetermined value K. Therefore, the friction coefficient μ of the forward clutch C1 and the hydraulic pressure The forward clutch C1 is always in a predetermined slip state regardless of individual differences in each part, such as variations in the urging force of the return spring of the cylinder, and changes over time, the engine load is reduced, fuel consumption is improved, and the creep force is appropriate To be controlled. Further, the feedback-controlled hydraulic pressure command value pc1 is stored as it is in the storage device 88 as the slip hydraulic pressure learning value gpc1fb, so that it is easy to set a slip engagement load that is in a predetermined slip state as compared with feedforward control or the like. It is.
[0045]
Further, the neutral means 100 at the time of stoppage adds the predetermined value pc1sw2 to the slip hydraulic pressure learned value gpc1fb at which the forward clutch C1 enters a predetermined slip state to obtain the hydraulic pressure command value immediately before slip (gpc1fb + pc1sw2), and the hydraulic pressure command value pc1 is obtained. The driving force fluctuation accompanying the start of slipping of the forward clutch C1 is performed in order to start the slip by slowing down the decreasing speed by the second sweep control after the first sweep control quickly decreases to the hydraulic pressure command value (gpc1fb + pc1sw2) immediately before the slip. It is possible to quickly achieve the neutral state while stopping while suppressing such shocks. In this case, the slip hydraulic pressure learning value gpc1fb is the hydraulic pressure command value pc1 obtained by feedback control that causes the forward clutch C1 to be in a predetermined slip state regardless of individual differences or changes with time of each part. The oil pressure command value immediately before the slip (gpc1fb + pc1sw2) determined based on the slip oil pressure learning value gpc1fb is also an appropriate value regardless of individual differences or changes with time of each part. The time until the forward clutch C1 starts to slip when a sudden change occurs until it reaches the hydraulic pressure command value immediately before slip (gpc1fb + pc1sw2) and a shock occurs, or on the contrary, the time when the slip starts slowly and becomes neutral when the vehicle stops ( It is possible to prevent the time lag) from becoming long.
[0046]
Further, the switching engagement control means 108 for controlling the transitional hydraulic pressure of the forward clutch C1 during the N → D garage shift is a constant pressure standby control after the first fill control, and sets the slip hydraulic pressure learning value gpc1fb to a predetermined value pc1st. The constant pressure standby command value (gpc1fb + pc1st) is obtained by addition and the garage shift hydraulic pressure PG is controlled to a hydraulic pressure corresponding to the constant pressure standby command value (gpc1fb + pc1st) to start the engagement of the forward clutch C1. The forward drive state can be achieved by promptly engaging the forward clutch C1 while suppressing shocks such as fluctuations in the driving force accompanying the start of engagement. In this case, the slip hydraulic pressure learning value gpc1fb is the hydraulic pressure command value pc1 obtained by feedback control that causes the forward clutch C1 to be in a predetermined slip state regardless of individual differences or changes with time of each part. The constant pressure standby command value (gpc1fb + pc1st) determined based on the slip hydraulic pressure learning value gpc1fb is also an appropriate value regardless of individual differences or changes with time of each part, and the forward clutch C1 is suddenly caused by individual differences or changes with time. It is possible to prevent the occurrence of a shock due to the engagement, and conversely the increase of the time (time lag) until the engagement is delayed and the forward drive state is established.
[0047]
As mentioned above, although the Example of this invention was described in detail based on drawing, this is an embodiment to the last, and this invention implements in the aspect which added various change and improvement based on the knowledge of those skilled in the art. Can do.
[Brief description of the drawings]
FIG. 1 is a skeleton diagram of a vehicle drive device to which the present invention is applied.
2 is a block diagram illustrating a control system of the vehicle drive device of FIG. 1. FIG.
FIG. 3 is a circuit diagram for explaining a portion related to hydraulic control of a forward clutch C1 and a reverse brake B1 of the forward / reverse switching device in the hydraulic control circuit provided in the vehicle drive device of FIG. 1;
4 is a block diagram for explaining a main part of functions provided in the electronic control unit of FIG. 2;
FIG. 5 is a flowchart for specifically explaining the processing content of the neutral means at the time of stopping in FIG. 4;
6 is an example of a time chart for explaining changes in the operating state of each part when neutral control at stop is performed according to the flowchart of FIG. 5;
7 is a flowchart for specifically explaining the processing content of the switching engagement control means in FIG. 4; FIG.
FIG. 8 is an example of a time chart for explaining changes in the operating state of each part when engagement transient hydraulic pressure control is performed during a garage shift according to the flowchart of FIG. 7;
[Explanation of symbols]
12: Engine (drive power source) 14: Torque converter (fluid power transmission device) 16: Forward / reverse switching device (power transmission mechanism) 60: Electronic control device 100: Neutral means at stop 106: Learning means 108: Time at switching Combined control means C1: Forward clutch (intermittent device) gpc1fb: Slip hydraulic pressure learning value (slip engagement load) gpc1fb + pc1sw2: Hydraulic pressure command value immediately before slip (engagement load just before slip) pc1: Hydraulic pressure command value (engagement load)

Claims (2)

Power transmission comprising: an interrupting device that transmits power by being frictionally engaged; and a fluid power transmission device that is provided between the interrupting device and a driving force source and transmits power via a fluid. Mechanism,
Lowering the engagement force of the interrupter when the vehicle is stopped by slipping Rutotomoni, as the speed ratio or the speed difference between the input and output rotation of the fluid type power transmission device becomes a predetermined value, the engagement load of the cross connection device A neutral means for stopping when reducing power transmission by feedback control ,
In a control device for a vehicle power transmission mechanism having
While comprising learning means for storing the feedback-controlled engagement load as a slip engagement load,
The neutral means at the time of stopping obtains an engagement load immediately before slipping immediately before the intermittent device slips based on the slip engagement load, and performs a first sweep control of the engagement load of the intermittent device to the engagement load immediately before the slip. When the engagement load immediately before the slip is reached, the slip is started by slowing down the lowering speed by the second sweep control. The engagement load immediately before the slip is determined by the oil temperature and the input. It is obtained by adding a predetermined value, which is set so as to increase as the oil temperature increases and increases as the input torque estimate increases, to the slip engagement load using a torque estimated value as a parameter. Control device for vehicle power transmission mechanism. Switching for controlling the engagement load at the time of the engagement transition of the intermittent device based on the slip engagement load at the time of driving switching from the disconnected state where the intermittent device is released to the drive state by engaging the intermittent device. The vehicle power transmission mechanism control device according to claim 1, further comprising an hour engagement control unit.

Images