JP5299310B2 - Control device for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an automatic transmission capable of reducing both judder and engaging shock when returning from neutral control. <P>SOLUTION: There is provided the control device for an automatic transmission, wherein target engine torque is controlled in return control from neutral control by a first target engine torque control means 116 in a step (SA4), feedback control is executed by a starting clutch control means 115 in a step (SA6) after request engine torque control by the first control means completed by a second target engine torque control means 118 in a step(SA5), the increase margin of engine torque is obtained during executing feedback control by the second target engine torque control means 118 in accordance with target engine torque controlled by the first target engine torque control means 116, and the control device is capable of reducing both judder and engaging shock as well as engaging the starting clutch in returning control from neutral control. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an automatic transmission control device, and more particularly, to a technique for controlling an automatic transmission upon return from neutral control.

  Neutral control is attracting attention as one of the control methods for automatic transmissions. For example, this is the technique described in Patent Document 1. In such neutral control, the automatic transmission is set to a neutral state in which power is not transmitted when the vehicle is stopped, and the fuel efficiency is improved by preventing dragging of the torque converter.

  When such neutral control is completed, the automatic transmission is switched from a state where power is not transmitted to a state where power is transmitted. Therefore, a shock may occur with the switching. In order to reduce such a shock, the input torque to the automatic transmission is controlled.

  Patent Document 1 discloses a vehicle control apparatus that performs engine torque control as the input torque control, and determines the end of the engine control based on the engine rotation speed and the input shaft rotation speed of the automatic transmission. Technology is disclosed.

JP 2009-191795 A

  By the way, when the neutral control is restored, for example, a hydraulic friction engagement device called a start clutch is engaged, and power is transmitted. At this time, judder (vibration / noise due to friction and vibration characteristics) may be generated with the engagement of the starting clutch. In order to reduce the judder, it is conceivable to increase the engagement hydraulic pressure of the starting clutch and increase the clutch torque of the starting clutch. However, when the clutch torque is increased, there is a problem that the engagement shock accompanying the engagement of the starting clutch increases. That is, the problem of achieving both reduction of judder and reduction of engagement shock has not been solved.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to provide an automatic transmission that can achieve both reduction of judder and reduction of engagement shock at the time of return from neutral control. It is to provide a control device.

In order to achieve this object, the invention according to claim 1 is directed to (a) an automatic transmission that performs feedback control so that a differential rotation speed of a starting clutch becomes a target clutch differential rotation speed in a return control from neutral control. (B) a first control means for limiting the required engine torque in the return control; and (c) executing the feedback control after the restriction of the required engine torque by the first control means is completed. (D) start clutch control means for controlling the engagement pressure of the start clutch so that the ratio of the change amount of the friction coefficient of the start clutch to the change amount of the rotational speed is 0 or more. (E) The first control means and the second control means may increase the required engine torque in accordance with an increase in the torque capacity of the starting clutch. And features.

In the invention according to claim 2 , the limitation of the required engine torque by the second control means is that the change gradient of the required engine torque is a difference between a change amount of the friction coefficient of the starting clutch and a change amount of the rotational speed. Is larger than the guard value of the engine torque at which the engine torque becomes 0 or more.

According to the first aspect of the present invention, the requested engine torque is limited in the return control by the first control means, and the feedback after the restriction of the requested engine torque by the first control means is finished by the second control means. Since the control is executed, an increase in torque is obtained when the feedback control is executed by the second control means when the required engine torque is limited by the first control means, so that the return from the neutral control is obtained. In the control, the start clutch can be engaged while reducing both judder and engagement shock. The starting clutch control means controls the engagement pressure of the starting clutch so that the ratio of the change amount of the friction coefficient of the starting clutch to the change amount of the rotational speed becomes 0 or more in the return control from the neutral control. In addition, since the required engine torque is increased according to the increase in the torque capacity of the starting clutch by the feedback control by the first control means and the second control means, the judder is reduced in the return control from the neutral control. Further, it is possible to achieve both reduction of engagement shock.

According to a second aspect of the present invention, the change gradient of the required engine torque is such that the ratio of the change amount of the friction coefficient of the starting clutch to the change amount of the rotational speed is 0 or more by the second control means. Since the engine torque is controlled to be larger than the guard value of the engine torque, the feedback control by the second control means can be sufficiently performed, and the judder and the engagement shock are reduced in the return control from the neutral control. Can be compatible.

1 is a skeleton diagram of a vehicle automatic transmission that is a part of a vehicle power transmission device to which the present invention is applied. FIG. FIG. 2 is an operation table for explaining an operation state of a friction engagement element, that is, a friction engagement device when a plurality of shift speeds are established in the automatic transmission of FIG. 1. FIG. 2 is a block diagram illustrating a schematic configuration of a main part of a control system provided in a vehicle for controlling the automatic transmission and the like of FIG. 1 and a power transmission system from an engine to driving wheels. FIG. 4 is a circuit diagram relating to a linear solenoid valve that controls the operation of clutch and brake hydraulic actuators (hydraulic cylinders) in the hydraulic control circuit of FIG. 3. It is a functional block diagram explaining the principal part of the control function by an electronic control apparatus. FIG. 7 is a shift diagram for determining a shift based on an actual vehicle speed and an accelerator opening from a relationship stored in advance with the vehicle speed and the accelerator opening as variables. It is a figure showing the relationship between the differential rotational speed in a clutch, and the friction coefficient with respect to pressing hydraulic pressure. It is a figure explaining the control action of the determination of the hydraulic gradient by a hydraulic gradient setting means in the figure showing the relationship between the differential rotational speed and the friction coefficient with respect to pressing hydraulic pressure. It is a flowchart explaining the control operation of the engine torque control in the main part of the control operation of the electronic control unit, that is, the release control from the neutral control. It is a flowchart explaining the control action of the pressing hydraulic pressure control in the main part of the control action of the electronic control unit, that is, the release control from the neutral control. It is a time chart for demonstrating the control action | operation in case cancellation | release control from neutral control in a present Example is performed.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a skeleton diagram of a vehicular automatic transmission 10 (hereinafter, automatic transmission 10) which is a part of a vehicular power transmission apparatus to which the present invention is applied. FIG. 2 is an operation table for explaining an operation state of the friction engagement element, that is, the friction engagement device when a plurality of shift speeds are established. The automatic transmission 10 is preferably used for an FF vehicle mounted in the left-right direction (horizontal) of the vehicle, and is a single pinion type first in a transmission case 26 as a non-rotating member attached to the vehicle body. A first transmission unit 14 mainly composed of one planetary gear unit 12, a double pinion type second planetary gear unit 16 and a single pinion type third planetary gear unit 18 are mainly composed of a Ravigneaux type. The second transmission unit 20 is provided on a common axis C, and the rotation of the input shaft 22 is shifted and output from the output rotation member 24. The input shaft 22 corresponds to an input member. In this embodiment, the input shaft 22 is a turbine shaft of a torque converter 32 as a fluid transmission device that is rotationally driven by an engine 30 that is a power source for traveling. The output rotating member 24 corresponds to the output member of the automatic transmission 10, and an output gear that meshes with the differential driven gear (large-diameter gear) 42 to transmit power to the differential gear device 40 shown in FIG. That is, it functions as a differential drive gear. The output of the engine 30 is transmitted to the pair of drive wheels 46 via the torque converter 32, the automatic transmission 10, the differential gear device 40, and the pair of axles 44 (see FIG. 3). The automatic transmission 10 and the torque converter 32 are substantially symmetrical with respect to the center line (axial center) C, and the lower half of the center line C is omitted in the skeleton diagram of FIG. .

  The torque converter 32 includes a lockup clutch 34 as a lockup mechanism that directly transmits the power of the engine 30 to the input shaft 22 without passing through fluid. The lock-up clutch 34 is a hydraulic friction clutch that is frictionally engaged by a differential pressure ΔP between the hydraulic pressure in the engagement-side oil chamber 36 and the hydraulic pressure in the release-side oil chamber 38, and is completely engaged (locked). The power of the engine 30 is directly transmitted to the input shaft 22 by being turned on. Further, the differential pressure ΔP, that is, the torque capacity is feedback-controlled so as to be engaged in a predetermined slip state, so that the turbine shaft (input shaft 22) has a predetermined slip amount of, for example, about 50 rpm when the vehicle is driven (power-on). Is rotated following the output rotation member of the engine 30, while the output rotation member of the engine 30 is rotated following the turbine shaft with a predetermined slip amount of, for example, about -50 rpm when the vehicle is not driven (power off). .

  The automatic transmission 10 corresponds to a combination of any one of the rotational states (sun gears S1 to S3, carriers CA1 to CA3, ring gears R1 to R3) of the first transmission unit 14 and the second transmission unit 20 according to the combination. Six forward shift stages (forward gear stages) from the first shift stage “1st” to the sixth shift stage “6th” are established, and the reverse shift stage (reverse gear stage) of the reverse shift stage “R” is established. It is done. As shown in FIG. 2, for example, in the forward gear stage, the first speed gear stage is engaged by the engagement of the clutch C1 and the brake B2, and the second speed gear stage is engaged by the engagement of the clutch C1 and the brake B1, and the clutch C1 is engaged. The third gear is set by engagement with the brake B3, the fourth gear is set by engagement of the clutch C1 and the clutch C2, and the fifth gear is set by engagement of the clutch C2 and the brake B3. The sixth gear is established by engaging the brake B1. Further, the reverse gear stage is established by the engagement of the brake B2 and the brake B3, and the neutral state is established by releasing any of the clutches C1, C2 and the brakes B1 to B3.

  The operation table of FIG. 2 summarizes the relationship between the above-mentioned shift speeds and the operation states of the clutches C1, C2 and the brakes B1 to B3, where “◯” indicates engagement and “◎” indicates only during engine braking. Represents the event. Particularly, since the one-way clutch F1 is provided in parallel to the brake B2 that establishes the first shift stage “1st”, only the clutch C1 is engaged and the engine brake is applied when starting (acceleration). Sometimes the clutch C1 and the brake B2 are engaged. Therefore, the so-called neutral control for suppressing the idling load of the engine 30 can be performed by setting the clutch C1 to the slipping state or the releasing state when the vehicle in which the first shift speed is established. Further, the gear ratios of the respective gear stages are the gear ratios of the first planetary gear device 12, the second planetary gear device 16, and the third planetary gear device 18 (= number of teeth of the sun gear / number of teeth of the ring gear) ρ1, ρ2. , Ρ3 as appropriate.

  The clutches C1 and C2 and the brakes B1 to B3 (hereinafter simply referred to as the clutch C and the brake B unless otherwise distinguished) are hydraulic friction engagement elements that are controlled by a hydraulic actuator such as a multi-plate clutch or a brake. (Hydraulic friction engagement device), the engagement and release states are switched by the excitation, de-excitation and current control of the linear solenoid valves SL1 to SL5 of the hydraulic control circuit 50 (see FIG. 3) and the engagement and release The transient oil pressure at the time is controlled.

  FIG. 3 is a block diagram illustrating a schematic configuration of a main part of a control system provided in the vehicle for controlling the automatic transmission 10 and the like of FIG. 1 and a power transmission system from the engine 30 to the drive wheels 46. .

  In FIG. 3, the electronic control unit 100 is configured to include a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface and the like, for example, and the CPU stores in the ROM in advance using the temporary storage function of the RAM. By performing signal processing according to the programmed program, output control of the engine 30, shift control of the automatic transmission 10, on / off control of the lock-up clutch 34, and the like are executed. It is divided into a shift control for controlling the linear solenoid valves SL1 to SL5 and a lock-up clutch control for controlling the linear solenoid valve SLU and the solenoid valve SL of the hydraulic control circuit 50.

For example, the electronic control unit 100 includes an accelerator opening signal indicating the accelerator opening Acc that is the operation amount of the accelerator pedal 52 detected by the accelerator opening sensor 54, and the rotation of the engine 30 detected by the engine rotation speed sensor 56. a signal indicative of the engine rotation speed N _E is a speed, a signal representing the cooling water temperature T _W of the engine 30 detected by a coolant temperature sensor 58, a signal representing the intake air quantity Q of the engine 30 detected by the intake air quantity sensor 60 , _A signal representing the intake air temperature TA detected by the intake air temperature sensor 62, a throttle opening signal representing the electronic throttle valve opening θ _TH detected by the throttle valve opening sensor 64, and a vehicle speed sensor 66 by rotational speed N _OUT ie vehicle speed signal corresponding to the vehicle speed V of the output rotary member 24, the brake Sui Operation of the foot brake pedal 68 shown in foot brake operation is a service brake, which is detected by the switch 70 (in depressing) (ON) signal representing the B _ON, the lever of the shift lever 72 detected by a lever position sensor 74 A signal representing the position (operation position, shift position) P _SH , a signal representing the turbine rotational speed N _T (= the rotational speed N _IN of the input shaft 22) detected by the turbine rotational speed sensor 76, and detected by the AT oil temperature sensor 78 A signal representing the AT oil temperature T _OIL which is the temperature of the hydraulic oil in the hydraulic control circuit 50 is supplied.

Further, the electronic control device 100 supplies a drive signal to a throttle actuator for operating the opening degree θ _TH of the electronic throttle valve, an ignition signal for instructing the ignition timing of the engine 30, and fuel to the intake pipe or cylinder of the engine 30. A fuel supply amount signal for controlling the fuel supply amount to the engine 30 by the fuel injection device to be stopped or stopped, a lever position P _SH display signal for operating the shift indicator, and a hydraulic control for switching the gear stage of the automatic transmission 10 A signal for controlling the shift solenoid that drives the shift valve in the circuit 50, a command signal for driving the linear solenoid valve for controlling the line pressure, a linear solenoid valve for controlling the engagement, release, and slip amount of the lockup clutch 34 A command signal or the like for driving is output.

  The shift lever 72 is disposed, for example, in the vicinity of the driver's seat, and is manually operated to five lever positions “P”, “R”, “N”, “D”, or “S” as shown in FIG. It has come to be.

  The “P” position (range) releases the power transmission path in the automatic transmission 10, that is, enters a neutral state (neutral state) in which the power transmission in the automatic transmission 10 is interrupted, and mechanically rotates the output by the mechanical parking mechanism. This is a parking position (position) for preventing (locking) the rotation of the member 24, and the “R” position is a reverse travel position (position) for reversing the rotation direction of the output rotation member 24 of the automatic transmission 10. The “N” position is a neutral position (position) for achieving a neutral state in which power transmission in the automatic transmission 10 is interrupted, and the “D” position is a shift range that allows the automatic transmission 10 to shift. In (D range), the forward travel position is set to execute the automatic shift control using all the forward gears from the first gear stage “1st” to the sixth gear stage “6th”. The “S” position is a forward travel that allows manual shifting by switching between multiple types of shift ranges that limit the range of gear change, that is, multiple types of shift ranges with different gears on the high vehicle speed side. Position.

In this “S” position, the shift range is shifted to the down side every time the shift lever 72 is operated, the “+” position as the lever position P _SH for shifting the shift range to the up side every time the shift lever 72 is operated. A “−” position is provided as a lever position P _SH for the movement. For example, in the “S” position, any of the “6” range to the “L” range is changed according to the operation of the shift lever 72 to the “+” position or the “−” position. The “L” range at the “S” position is also an engine brake range for obtaining a further engine braking effect by engaging the brake B2 at the first gear stage “1st”.

  The “D” position is an automatic transmission mode that is a control mode in which automatic transmission control is executed in the range of the first to sixth gears, for example, as shown in FIG. The “S” position is a lever position to be selected. In the “S” position, automatic shift control is executed in a range not exceeding the highest speed gear of each shift range of the automatic transmission 10 and the shift changed by manual operation of the shift lever 72 It is also a lever position for selecting a manual shift mode that is a control mode in which the manual shift control is executed based on the range (that is, the highest speed gear stage).

4 is a linear solenoid valve that controls the operation of the hydraulic actuators (hydraulic cylinders) A _C1 , A _C2 , A _B1 , A _B2 , A _B3 of the clutches C1, C2 and the brakes B1 to B3 in the hydraulic control circuit 50. It is a circuit diagram regarding SL1 to SL5.

In FIG. 4, each hydraulic actuator A _C1 , A _C2 , A _B1 , A _B2 , A _B3 has a line oil pressure PL corresponding to a command signal from the electronic control unit 100 by linear solenoid valves SL1 to SL5. The pressure is adjusted to P _C1 , P _C2 , P _B1 , P _B2 , and P _B3 and supplied directly. This line oil pressure PL is obtained by using, for example, a relief type pressure regulating valve (regulator valve) (not shown) with the hydraulic pressure generated from a mechanical oil pump 28 (see FIG. 1) rotated and driven by the engine 30 as a source pressure. The pressure is adjusted to a value corresponding to the engine load or the like represented by the opening.

The linear solenoid valves SL1 to SL5 have basically the same configuration, and are excited and de-energized independently by the electronic control unit 100, and the hydraulic pressure of each hydraulic actuator A _C1 , A _C2 , A _B1 , A _B2 , A _B3 . Are independently regulated to control the engagement pressures P _C1 , P _C2 , P _B1 , P _B2 , and P _{B3 of} the clutches C1 to C4 and the brakes B1 and B2. In the automatic transmission 10, for example, as shown in the engagement operation table of FIG. 2, each gear stage is established by engaging a predetermined engagement device. In the shift control of the automatic transmission 10, for example, a so-called clutch-to-clutch shift is performed in which release and engagement of the clutch C and the brake B involved in the shift are controlled simultaneously. For example, as shown in the engagement operation table of FIG. 2, in the upshift from the 3rd speed to the 4th speed, the brake B3 is released and the clutch C2 is engaged, so that the release transient hydraulic pressure of the brake B3 is suppressed so as to suppress the shift shock. And the engagement hydraulic pressure of the clutch C2 are appropriately controlled.

FIG. 5 is a functional block diagram illustrating the main part of the control function of the electronic control device 100. In FIG. 5, the engine output control means 102 controls opening and closing of an electronic throttle valve by a throttle actuator for throttle control, controls fuel injection by a fuel injection device for fuel injection control, and controls ignition timing. The output control of the engine 30 is executed by controlling the ignition timing by an ignition device such as an igniter. For example, the engine output control unit 102 drives the throttle actuator based a predetermined stored relationship of the accelerator opening signal Acc, the throttle control to increase the throttle valve opening theta _TH as the accelerator opening Acc is increased Execute. Specifically, for example, the engine output control means 102 can perform control so that the engine torque output from the engine 30 becomes the required engine torque instructed by the neutral control return means 110 described later.

  The shift control means 104 determines shift based on the actual vehicle speed V and the accelerator opening Acc from the relationship (map, shift diagram) stored in advance with the vehicle speed V and the accelerator opening Acc as variables, for example, as shown in FIG. To determine whether or not the automatic transmission 10 should be shifted. For example, the automatic transmission 10 is automatically determined so as to obtain the determined shift speed. Shift control is executed. At this time, the shift control means 104 engages and / or releases the hydraulic friction engagement device involved in the shift of the automatic transmission 10 so that the shift stage is achieved according to, for example, the engagement table shown in FIG. A command (shift output, hydraulic command) is output to the hydraulic control circuit 50.

The hydraulic control circuit 50 operates the linear solenoid valves SL1 to SL5 in the hydraulic control circuit 50 so that the shift of the automatic transmission 10 is executed according to the command, and the hydraulic friction engagement device involved in the shift Hydraulic actuators A _C1 , A _C2 , A _B1 , A _B2 , A _B3 are operated.

  In the shift diagram of FIG. 6, the solid line is a shift line (upshift line) for determining an upshift, and the broken line is a shift line (downshift line) for determining a downshift. Further, the shift line in the shift diagram of FIG. 6 indicates whether or not the actual vehicle speed V has crossed the line on the horizontal line indicating the actual accelerator opening Acc (%), that is, the value on which the shift on the shift line is to be executed ( This is for determining whether or not the shift point vehicle speed) VS has been exceeded, and is also stored in advance as a series of this value VS, that is, the shift point vehicle speed.

The neutral control condition determination unit 106 determines whether or not a predetermined neutral control condition is satisfied at the travel position of the shift lever 72. The predetermined neutral control condition is, for example, that the vehicle is stopped, the accelerator pedal 52 is not depressed, and the foot brake pedal 68 is depressed. More specifically, the neutral control condition determination unit 106 determines that the vehicle speed V is equal to or less than a predetermined stop determination value and the brake switch 70 is ON B _ON , for example, when the lever position P _SH is the “D” position. In this case, it is determined that the neutral control condition is satisfied.

In addition, the neutral control condition determination unit 106 determines whether or not the predetermined neutral control condition is satisfied during the neutral control by the neutral control unit 108 to be described later, thereby releasing (ending) the neutral control. It is also a neutral control release determination means that sequentially determines whether or not, that is, sequentially determines whether or not to return from neutral control. Specifically, the neutral control condition determination unit 106 determines the start of the neutral control release when the brake switch 70 is not turned _ON during the neutral control.

  When the neutral control condition determining means 106 determines that the predetermined neutral control condition is satisfied, for example, at the “D” position of the shift lever 72, the neutral control means 108 is used to achieve the first gear. Neutral control that outputs a neutral command to put the clutch C1 that is an engagement device into a slipping state or a releasing state to the shift control means 104 so that the power transmission path including the automatic transmission 10 is in a power transmission suppression state or a power transmission cut-off state. Execute. The shift control means 104 outputs to the hydraulic control circuit 50 a control signal for reducing the engagement pressure of the clutch C1 in accordance with a predetermined pattern so that the clutch C1 is in the slip state or the release state in accordance with the neutral command. . When the power transmission in the automatic transmission 10 is suppressed or cut off (released), the torque converter 32 rotates substantially integrally and the idling load of the engine 30 is suppressed, and fuel consumption and NVH (noise / vibration / riding) are reduced. Comfort) performance is improved.

  Thus, in this neutral control, the clutch C1 is disengaged (a state just before engagement that slightly slips in engagement), for example, so that the power transmission path in the automatic transmission 10 is substantially disengaged. On the other hand, a start standby state is set in which the clutch C1 can start immediately by switching from half-engagement to engagement.

  When the neutral control condition determination unit 106 determines that the neutral control is canceled during neutral control, the neutral release control unit 110 sets the power transmission path including the automatic transmission 10 to a power transmission enabled state. A neutral control release command for increasing the torque transmission capacity of the clutch C1, which is the engaging side engaging device for the first gear, is output to the shift control means 104. The clutch C1 corresponds to the starting clutch of the present invention.

  By the way, when the neutral control return means 110 is executed, the clutch C1, which is an engaging device, is engaged. At this time, a torque step due to a deviation between the clutch torque at the end of engagement (clutch torque capacity) and the input torque. In order to avoid this, feedback control is performed on the amount of change in the target differential rotation speed. In such feedback control, the friction material pressing pressure in the clutch C1 changes due to the differential rotation speed and the engagement hydraulic pressure. If Δμ which is the amount of change in the friction coefficient μ of the friction material of the clutch C1 and the amount of change ΔV in the differential rotational speed V satisfy the relationship Δμ / ΔV <0, the state of the clutch C1 becomes unstable and judder occurs. I know you will.

  On the other hand, in order to avoid or reduce such judder, it is conceivable to change the behavior of the engagement hydraulic pressure so that Δμ / ΔV> 0. However, in a general hydraulic friction engagement device, the behavior of the engagement hydraulic pressure is a change in the direction in which the hydraulic pressure increases. Therefore, when the clutch is engaged, the deviation between the clutch torque and the input torque increases, and the engagement shock may deteriorate.

  In order to solve such a problem, the neutral control return means 110 of the present embodiment has a target differential rotational speed change setting means 112, a differential rotational speed detection means 113, a hydraulic pressure gradient setting means 114, an engagement hydraulic pressure setting means 115, a first request. The engine torque control means 116, the second required engine torque control means 118, and the guard value setting means 120 are functionally provided.

  Among these, the target difference rotation speed change setting means 112 sets a target value ΔVtgt of a change amount ΔV per predetermined minute time of the difference rotation speed V between the two rotation elements engaged by the clutch C1, which is the starting clutch. Specifically, the target value ΔVtgt of the temporal change in the differential rotational speed of the clutch C1 is, for example, from the viewpoint of drivability in the return control from the neutral control, that is, from the viewpoint of reducing the uncomfortable feeling given to the driver. It is set based on the torque that is allowed to be generated.

  The differential rotational speed detection means 113 detects a differential rotational speed V (hereinafter simply referred to as the differential rotational speed V of the clutch C1), which is the difference between the rotational speeds of the two rotational elements engaged with the clutch C1. Specifically, for example, the rotational speed NOUT of the output rotating member 24 of the automatic transmission 10 detected by the vehicle speed sensor 66, the turbine rotational speed NT detected by the turbine rotational speed sensor 76 (= the rotational speed NIN of the input shaft 22). Based on the gear ratio γ and the like of the automatic transmission 10, the differential rotational speed V between the two rotating elements engaged by the clutch C1 is detected. Further, the differential rotational speed detection means 113 calculates a differential rotational speed change ΔV that is a predetermined amount of change per minute time of the detected differential rotational speed V.

  The hydraulic gradient setting means 114 sets the gradient ΔP in the change of the engagement hydraulic pressure P of the clutch C1 that is the starting clutch based on the differential rotation speed change amount ΔV detected by the differential rotation speed change setting means 112. Specifically, for example, the electronic control unit 100 stores in advance the relationship between the differential rotational speed V, the friction coefficient μ of the clutch C1, and the engagement hydraulic pressure (pressing hydraulic pressure) P of the clutch C1 as shown in FIG. ing. Then, the hydraulic gradient setting means 114 sets the engagement hydraulic pressure gradient ΔP of the clutch C1 using this stored relationship.

  FIG. 7 is a graph showing the relationship between the differential rotational speed V, the friction coefficient μ of the clutch C1, and the engagement hydraulic pressure (pressing hydraulic pressure) P of the clutch C1. In FIG. 7, the horizontal axis is provided with a differential rotational speed V of the clutch C1, and the vertical axis is provided with a coordinate plane representing the pressing hydraulic pressure P of the clutch C1, and each position on the coordinate plane, that is, the differential rotational speed V and The friction coefficient μ of the clutch C1 corresponding to the combination of the pressing hydraulic pressures P is shown in contour lines. Note that the differential rotational speed V of the clutch C1 represented by the horizontal axis of FIG. 7 is made smaller as it goes to the right. That is, the differential rotational speed decreases as the engagement of the clutch C1 proceeds, and the point representing the state of the clutch C1 moves to the right side of the drawing as the engagement proceeds. Further, as shown in FIG. 7, the lower the pressing hydraulic pressure P, the higher the friction coefficient μ generally.

  FIG. 8 is a partially enlarged view of part of FIG. Hereinafter, the control operation for determining the hydraulic gradient ΔP by the hydraulic gradient setting means 114 will be described with reference to FIG. Also in FIG. 8, as in FIG. 7, the horizontal axis is provided with a differential rotational speed V of the clutch C <b> 1, and the vertical axis is provided with a pressing hydraulic pressure P of the clutch C <b> 1. That is, the friction coefficient μ of the clutch C1 corresponding to the combination of the differential rotation speed V and the pressing hydraulic pressure P is indicated by contour lines by L1 to L3. That is, the friction coefficient μ at each point on the line L1 is μ1, the friction coefficient μ at each point on the line L2 is μ2 larger than the μ1, and the friction coefficient μ at each point on the line L3 is It is μ3 smaller than the μ1.

A point S1 in FIG. 8 represents the state of the clutch C1 at a certain point in time. The differential rotational speed is V1, the pressing hydraulic pressure is P1, and the friction coefficient is μ1. Consider a case where the differential rotational speed of the clutch C1 changes by the target differential rotational speed change amount ΔV for the clutch C1 in the state represented by this point S1. As shown in FIG. 8, when the target differential rotational speed change amount of the clutch C1 changes by ΔV (decreases in the example of FIG. 8), the pressing hydraulic pressure P changes by ΔPth shown in FIG. 8 (in the example of FIG. 8). Is increased), the clutch C1 after the change is in a state represented by a point S2 in FIG. This corresponds to the arrow A2 in FIG. In the state represented by this point S2, the differential rotational speed of the clutch C1 is V1 + ΔV, and the pressing hydraulic pressure is P1 + ΔPth. Here, since both the points S1 and S2 are on the line L1, the friction coefficient when the clutch C1 is in a state corresponding to the point S1 and in the state corresponding to the point S2 is both μ1. . Therefore, when the differential rotational speed decreases by ΔV, if the pressing hydraulic pressure ΔPth increases, the friction coefficient change amount Δμ becomes zero. Therefore, Δμ / ΔV = 0. Similarly, when the differential rotational speed is decreased by ΔV, if it is increased or decreased by a value smaller than the pressing hydraulic pressure ΔPth, for example, the friction coefficient increases as shown by the arrow A1 in FIG. The amount Δμ is Δμ> 0. Therefore, Δμ / ΔV <0. Further, when the differential rotational speed is decreased by ΔV, if the differential rotational speed increases by a value larger than the pressing hydraulic pressure ΔPth, for example, the friction coefficient decreases as shown by an arrow A3 in FIG. 0. Therefore, Δμ / ΔV> 0.

  Thus, in order to satisfy Δμ / ΔV ≧ 0 when the differential rotational speed is decreased by ΔV, the pressing hydraulic pressure only needs to be increased by ΔPth or more. In this way, the hydraulic gradient setting means 114 determines the hydraulic gradient ΔP when the differential rotational speed changes by ΔV as ΔPth. When the hydraulic pressure gradient ΔP of the pressing hydraulic pressure is only required to be equal to or greater than ΔPth, the hydraulic gradient setting means 114 determines the hydraulic pressure gradient ΔP as ΔPth as the value of ΔP decreases. This is because becomes smaller.

  The starting clutch control means 115 is based on the target value ΔVtgt of the time change of the differential rotational speed set by the target differential rotational speed change setting means 112 and the time change ΔV of the differential rotational speed calculated by the differential rotational speed detection means 113. Thus, the pressing hydraulic pressure P of the clutch C1, which is the starting clutch, is set. Specifically, for example, feedback control is executed to change the clutch torque of the clutch C1 so that the deviation between the target value ΔVtgt of the time difference in the differential rotational speed and the time change ΔV of the actual differential rotational speed becomes small.

  In addition to the feedback control, the starting clutch control means 115 changes the hydraulic pressure so as to be equal to the pressing hydraulic pressure gradient ΔP when the hydraulic pressure gradient setting means 114 sets the pressing hydraulic pressure gradient ΔP.

  The first required engine torque control means 116 limits the value of the required engine torque when the neutral control condition determination means 106 determines the end of the neutral control, that is, the execution of the return control from the neutral control. The limitation on the value of the required engine torque will be described later. The control by the first request engine torque control means 116 is executed from the start of the return control from the neutral control to the elapse of a predetermined time, specifically until the execution of control by the second request engine torque control means 118 described later, for example. . The first required engine torque control means 116 corresponds to the first control means of the present invention.

The second required engine torque control means 118 controls the required engine torque so that the change in the pressing hydraulic pressure P of the clutch C1 becomes the pressing hydraulic pressure gradient ΔP set by the hydraulic pressure gradient setting means 114. The required engine torque control by the second required engine torque control means 118 is started when the differential rotational speed V starts to decrease in the engagement of the clutch C1, for example, and is executed until the engagement is completed. Specifically, the equation of motion of the clutch C1 uses the engine torque (input torque of the clutch C1) Te, the clutch torque Tcl of the clutch C1, the inertia I of the clutch C1, and the rotational angular velocity ω of the clutch C1 Te−Tcl = I · (d / dt) ω (1)
When the engine torque Te is increased while the clutch torque Tcl is increased accordingly, the inertia I and the amount of change (d / dt) ω of the rotational angular velocity do not change. Based on such characteristics, when the pressing hydraulic pressure gradient ΔP is set by the hydraulic pressure gradient setting unit 114, the second required engine torque control unit 118 balances the engine torque with the clutch torque Tcl that satisfies the pressing hydraulic pressure gradient ΔP. The required engine torque is controlled so that the engine torque Te is changed by the gradient ΔTe so as to be output. The relationship between the pressing hydraulic pressure of the clutch C1 and its clutch torque Tcl can be obtained in advance experimentally or by simulation or the like. Therefore, the clutch torque Tcl of the clutch C1 is determined based on the pressing hydraulic pressure P and the obtained relationship. Can be obtained. In the following, the required engine torque gradient ΔTe set in this way is referred to as a required engine torque gradient ΔTe corresponding to the pressing hydraulic pressure gradient ΔP. Further, when the return control from the neutral control is completed, that is, when the engagement of the clutch C1 is completed, the engine torque determined based on the accelerator opening Acc is controlled. Then, the engine output control means 102 is controlled based on the required engine torque. The second required engine torque control means 118 corresponds to the second control means of the present invention.

  Next, the restriction of the required engine torque value by the first required engine torque control means 116 will be described. As described above, the engine torque limit by the second required engine torque control means 118 is such that the engine torque Te is the gradient of the pressing hydraulic pressure so that the engine torque Te is balanced with the clutch torque Tcl that satisfies the pressing hydraulic pressure gradient ΔP. The output is changed by a gradient ΔTe corresponding to ΔP, and at the end of the return control from the neutral control, the engine torque determined based on the accelerator opening Acc is controlled. For this reason, the first required engine torque control means 116 secures an increase in the engine torque Te (corresponding to Te2-Te1 in FIG. 11) by the second required engine torque control means regardless of the accelerator opening Acc. Control the value of the requested engine torque. More specifically, in the second required engine torque control means 118, the engine is accompanied with the pressure ΔP of the pressing hydraulic pressure from when the differential rotational speed V of the clutch C1 starts to decrease until the engagement is completed. Since the torque Te is increased to be the engine torque based on the accelerator opening Acc, the required engine torque is set to be smaller than the value obtained by subtracting the increase in the engine torque from the engine torque based on the accelerator opening Acc. The value of is controlled.

  The guard value setting means 120 controls the change gradient of the required engine torque during the control by the second required engine torque control means 118 so as to be larger than a predetermined guard value. This guard value is, for example, the change gradient ΔP of the pressing hydraulic pressure P of the clutch C1 set by the hydraulic gradient setting means 114, that is, the change gradient ΔTeth of the engine torque Te corresponding to ΔPth. In other words, the difference Δμ of the friction coefficient μ of the clutch C1 is the difference gradient of the engine torque corresponding to the smallest pressing hydraulic pressure ΔPth at which the gradient Δμ / ΔV with respect to the variation ΔV of the rotational speed V becomes Δμ / ΔV> 0. Is set as follows. Thus, even when the accelerator is stepped back during the execution of the second required engine torque control means 118, that is, when the accelerator opening degree Acc is changed to be small, the time of the required engine torque It is possible to suppress the occurrence of judder when the gradient is smaller than the guard value ΔTeth.

  FIG. 8 is a flowchart for explaining the control operation of the engine torque control in the control operation of the electronic control device 100, that is, the release control from the neutral control. For example, an extremely short cycle time of about several msec to several tens msec. Is executed repeatedly.

  First, in a step (hereinafter, “step” is omitted) SA1 corresponding to the neutral control condition determining means 106, it is determined whether or not the return control from the neutral control is executed. That is, when the neutral control is already executed and the condition for the return control from the neutral control is satisfied, the determination at this step is affirmed and SA2 is executed. On the other hand, when the neutral control is not executed or when the condition for the return control from the neutral control is not satisfied, the determination of this step is denied and the present flowchart is ended.

  In SA2 corresponding to the hydraulic gradient setting means 114, when the change amount of the differential rotational speed is ΔV, a pressing hydraulic pressure gradient ΔP determined so as not to satisfy Δμ / ΔV <0 is set.

  In SA3 corresponding to the first required engine torque control means 116 and the second required engine torque control means 118, the value of the required engine torque limited in SA4 described later is calculated. The value of the required engine torque is set to a value sufficient to secure a margin for increasing the engine torque that is increased in SA6 described later.

  In SA4 corresponding to the first required engine torque control means 116, the required engine torque is limited to the engine torque value calculated in SA3.

  SA5 and SA6 correspond to the second required engine torque control means 118. Among these, at SA5, it is determined whether or not the reduction of the differential rotational speed of the clutch C1 has started. When the differential rotation speed of the clutch C1 starts to decrease, the determination in this step is affirmed, the restriction of the requested engine torque is ended, and SA6 is executed. On the other hand, if the differential rotation speed of the clutch C1 has not started to decrease, the determination at this step is denied and the restriction of the requested engine torque is continued.

  In SA6, the value of the requested engine torque is increased. In this step, the required engine torque Te is changed so that the engine torque Te is balanced with the clutch torque Tcl generated corresponding to the hydraulic pressure gradient ΔP set in SA2.

  SA7 and SA8 correspond to the guard value setting means 120. First, at SA7, it is determined whether or not the accelerator pedal is stepped back, that is, whether or not the accelerator opening degree Acc has decreased. If the accelerator opening Acc has decreased, the determination at this step is affirmed and SA8 is executed. If the accelerator opening degree Acc has not decreased, the determination in this step is denied, and the control of SA6 is executed until the return control from the neutral control is completed, that is, until the engagement of the clutch C1 is completed.

  In SA8, the change gradient of the required engine torque is controlled so as not to fall below a preset guard value. This guard value is, for example, a change gradient of the engine torque corresponding to the change gradient ΔP of the pressing hydraulic pressure P of the clutch C1 set at SA2.

  FIG. 9 is a flowchart for explaining the control operation of the pressing hydraulic pressure control of the clutch C1 in the control operation of the electronic control device 100, that is, the release control from the neutral control. It is executed repeatedly with a short cycle time.

  First, in SB1 corresponding to the target differential rotational speed change setting means 112, a predetermined differential rotational speed target value ΔVtgt is read. This target value ΔVtgt of the differential rotation speed is designed in advance from the viewpoint of drivability in the return control from the neutral control, that is, from the viewpoint of reducing the uncomfortable feeling given to the driver.

  Subsequently, in SB2 corresponding to the differential rotation speed detection means 113, the differential rotation speed V of the clutch C1 is detected. Specifically, for example, the rotational speed NOUT of the output rotating member 24 of the automatic transmission 10 detected by the vehicle speed sensor 66, the turbine rotational speed NT detected by the turbine rotational speed sensor 76 (= the rotational speed NIN of the input shaft 22). , Based on the gear ratio γ of the automatic transmission 10 and the like. Further, a difference rotational speed change ΔV that is a predetermined amount of change per minute time of the detected differential rotational speed V is calculated.

  SB3 to SB6 correspond to the starting clutch control means 115. Among these, in SB3, the pressing hydraulic pressure P is calculated such that the deviation between the target value ΔVtgt of the differential rotational speed read in SB1 and the differential rotational speed change ΔV detected in SB2 becomes zero. This control is, for example, feedback control performed using a predesigned gain or the like.

  In SB4, it is determined whether or not the control by the second request engine torque control means 118 is being executed. When the control by the second request engine torque control means 118 is being executed, the determination in this step is affirmed because the pressing hydraulic pressure P needs to satisfy the hydraulic gradient ΔP set by the hydraulic gradient setting means 114 or the like. , SB5 are executed. On the other hand, if the control by the second required engine torque control means 118 is not being executed, the pressing hydraulic pressure P may be based on the feedback control calculated in SB3, the determination of this step is denied, and SB6 is Executed.

  In SB5, the pressing oil pressure P calculated in SB3 is changed so as to satisfy the set oil pressure gradient ΔP.

  In SB6, the shift control is performed so that the pressing hydraulic pressure P calculated in SB3 when the determination of SB4 is negative, and the pressing hydraulic pressure P changed in SB5 when the determination of SB4 is positive. The pressing hydraulic pressure of the clutch C1 is controlled via the means 104.

  FIG. 10 is a time chart for explaining the control operation when the release control from the neutral control in this embodiment is executed.

If the brake pedal 68 is turned off (brake SW off) at the time point t1 in a state where the neutral control is being executed, the neutral control condition determination means 106 determines that the neutral control release control is executed, and the neutral control return means. The return control from the neutral control by 110 is started. Specifically, at the time point t1, the engagement hydraulic pressure P _C1 (command hydraulic pressure) of the clutch C1, which is an engagement device that establishes the first gear, as shown by the solid line, is rapidly increased, whereby the clearance of the clutch C1 is increased. A so-called first fill is performed.

  Then, the accelerator pedal 52 is depressed at time t2, but the required engine torque at this time is limited by the first required engine torque control means 116 instead of the required engine torque corresponding to the value of the accelerator opening Acc. The value Te1. In FIG. 10, a broken line indicates an example when this control is not executed. That is, when this control is not executed, the required engine torque corresponds to the accelerator opening Acc.

  When the differential rotational speed of the clutch C1 starts to decrease at t3, control by the second request engine torque control means 118 is performed instead of control by the first request engine torque control means 116. That is, the value of the required engine torque is the value of the required engine torque corresponding to the change gradient ΔP of the pressing hydraulic pressure of the clutch C1 set in the hydraulic gradient setting means 114. In FIG. 10, the engagement hydraulic pressure P of the clutch C1 is increased stepwise before t3. This is the target value ΔVtgt of the time change of the differential rotation speed performed by the start clutch control means 115. This is based on feedback control based on the deviation between the time difference ΔV and the actual differential rotational speed.

  At this time, as shown by the solid line in FIG. 10, the pressing hydraulic pressure of the clutch C1 is changed so that the time change amount becomes ΔP. On the other hand, when the present invention is not applied and the feedback control based only on the deviation between the target change amount ΔVtgt of the differential rotation speed and the actual change amount ΔV of the differential rotation speed is performed, In FIG. 10, it is represented by a broken line. In this way, when the present invention is not applied and the feedback control is performed, the pressing hydraulic pressure P of the clutch C1 decreases, so the time change amount Δμ of the friction coefficient of the clutch C1 and the time change amount ΔV of the differential rotational speed. When the present invention is applied, the pressing hydraulic pressure P of the clutch C1 increases, and Δμ / ΔV> 0, so that judder is generated. Does not occur.

  Further, the increase of the pressing hydraulic pressure P of the clutch C1 is performed so that the torque of the clutch C1 and the increase of the required engine torque Te are balanced, and therefore, the rotational angular speed and inertia of the rotating element in the clutch C1 may be affected. And the uncomfortable feeling given to the driver is suppressed. As described above, when ΔPth, which is the smallest value in the range that the change gradient ΔP can take, is set by the hydraulic gradient setting means 114 as the change gradient ΔP of the pressing hydraulic pressure P of the clutch C1, t3 to The change gradient ΔTe of the requested engine torque at t4 is the same as the guard value ΔTeth. This guard value ΔTeth is represented by a two-dot chain line in FIG. When such a guard value is provided, for example, even when the accelerator pedal is stepped back, the change gradient ΔTeth of the required engine torque does not become smaller than the guard value ΔTeth. That is, the gradient does not become gentler than that of the two-dot chain line in FIG.

  At t4, the engagement of the clutch C1, which is the starting clutch, is completed. At this time, the value of the required engine torque is controlled to be a value Te2 corresponding to the accelerator opening Acc.

  According to the above-described embodiment, the required engine torque is limited in the return control from the neutral control by the first required engine torque control means 116 (SA4), and the first control is performed by the second required engine torque control means 118. After the restriction of the requested engine torque by the means is finished (SA5), the feedback control by the starting clutch control means 115 is executed (SA6), so that the requested engine torque is restricted by the first requested engine torque control means 116. Along with this, a margin for increasing the engine torque is obtained when the second required engine torque control means 118 executes the feedback control. In the return control from the neutral control, both the reduction of the judder and the reduction of the engagement shock are achieved and the engagement of the start clutch is achieved. Can be done.

  Further, according to the above-described embodiment, the start clutch control means 115 causes the gradient of the difference Δμ in the friction coefficient μ of the clutch C1 as the start clutch to the change ΔV in the rotational speed V in the return control from the neutral control. The engagement pressure of the start clutch is controlled so that the value becomes 0 or more, and the torque capacity of the start clutch is controlled by feedback control by the first request engine torque control means 116 and the second request engine torque control means 118. Since the required engine torque Te is increased as Tcl increases, both judder reduction and engagement shock reduction can be achieved in return control from neutral control.

  Further, according to the above-described embodiment, the change gradient of the required engine torque Te is determined by the change amount of the friction coefficient μ of the clutch C1 as the starting clutch by the second required engine torque control means 118 and the guard value setting means 120. Since the gradient (Δμ / ΔV) with respect to the change amount ΔV of the difference rotational speed ΔΔ is controlled to be larger than the guard value of the engine torque that becomes 0 or more (SA8), the second required engine torque control means 118 From the feedback control, it is possible to achieve both reduction of judder and reduction of engagement shock in the return control from the neutral control.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  For example, in the above-described embodiment, the automatic transmission 10 is a stepped transmission having six forward speeds and one reverse speed, but is not limited thereto. For example, when the automatic transmission 10 is a stepped transmission, the number of shift stages is not limited. Further, the automatic transmission is not limited to the internal transmission disclosed in the embodiment, and may be a so-called double clutch type automatic transmission. Further, the automatic transmission 10 may be a continuously variable transmission (CVT) as long as it has an engagement device that can shut off power when neutral control is executed, such as a starting clutch. That is, the present invention can be applied as long as neutral control can be performed and a predetermined engagement device is engaged when neutral control is canceled. Further, a lock-up clutch 34 of the torque converter 32 may be used as a starting clutch instead of the clutch C1.

  In the above-described embodiment, the clutch C1 functions as an engagement device. However, the clutch C1 does not necessarily function as an engagement device, and is appropriately changed according to the internal structure of the automatic transmission. Is done.

In the above-described embodiment, the differential rotational speed V of the clutch C1 is calculated based on the output shaft rotational speed NOUT and the turbine rotational speed _NT . However, the present invention is not limited to this, and for example, the vehicle speed may be used. .

  In the above-described embodiment, the first required engine torque control means 116 and the second required engine torque control means 118 are switched when the differential rotational speed V of the clutch C1 starts to decrease. It is not limited to. For example, it may be switched when a predetermined time elapses from the start of the return control from the neutral control.

  In the above-described embodiment, the setting of the guard value by the guard value setting means 120 (SA7, SA8) is executed when the accelerator pedal is stepped back, that is, when the accelerator opening degree Acc is decreased. Instead, it can be executed when an operation for reducing the required engine torque is performed. Further, the guard value setting means 120 is not essential in the implementation of the present invention, and a certain effect can be produced even if it is not provided.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

10: Automatic transmission 30: Engine 46: Drive wheel 52: Accelerator pedal 108: Neutral control means 106: Neutral control condition determination means 110: Neutral control return means 114: Hydraulic gradient setting means 115: Start clutch control means 116: First Required engine torque control means (first control means)
118: Second required engine torque control means (second control means)
120: Guard value setting means C1: Clutch (starting clutch)
Teth: Guard value of required engine torque ΔPth: Guard value of change amount of engagement hydraulic pressure (pressing hydraulic pressure)

Claims (2)

A control device for an automatic transmission that performs feedback control so that the differential rotation speed of the starting clutch becomes the target clutch differential rotation speed in the return control from the neutral control,
First control means for limiting the required engine torque in the return control;
Second control means for executing the feedback control after the restriction of the requested engine torque by the first control means is completed;
It possesses a starting clutch control means for controlling the engagement pressure of the starting clutch such that the ratio for amount of change in the differential rotational speed of the variation of the friction coefficient of the starting clutch becomes 0 or more,
The control apparatus for an automatic transmission, wherein the first control means and the second control means increase a required engine torque in accordance with an increase in torque capacity of the starting clutch . The restriction of the required engine torque by the second control means is that the change gradient of the required engine torque is a guard value of the engine torque at which the ratio of the change amount of the friction coefficient of the starting clutch to the change amount of the rotational speed is 0 or more. The control device for an automatic transmission according to claim 1 , wherein the control device is larger.

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