JP2006170150A - Control device for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an automatic transmission capable of starting without sense of incongruity at a time of restart of an engine after idling stop on a slope or the like. <P>SOLUTION: The control device for the automatic transmission performing idling stop control is provided with a rotation speed detection means detecting rotation speed equivalent value of a drive wheel, a road inclination judgment means judging whether rotation speed detected by the rotation speed detection means right after engine restart is rising or not, judging that the road is a slope if the speed is rising and judging that the road is flat surface if the speed is not rising, a torque down control means outputting torque down quantity limiting engine input torque according to a plurality of phases to the engine control means and a torque down quantity correction means performing correction to make the torque down quantity large when the road inclination judgment means judges that the road is slope. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control device for an automatic transmission having an idle stop control.

As a control device for an automatic transmission having an idle stop control, a technique described in Patent Document 1 is disclosed. In this publication, at the time of start by engine restart after idling stop, the engagement pressure control for engaging the forward clutch is performed by the lockup solenoid for adjusting the lockup clutch engagement pressure of the torque converter, and after the engagement, the clutch regulator By switching to the fastening pressure regulated in the high pressure region by the valve, fine fastening pressure control in the low pressure region is achieved.
JP 2004-239351 A

  In a vehicle that performs such idle stop control, at the time of restart after engine restart, a sufficient amount of oil is not secured in the starting clutch, and gradually from the viewpoint of avoiding a fastening shock. The fastening shock is avoided by fastening the starting clutch. However, on the uphill road and downhill road, since the gravitational acceleration component is loaded on the inertia of the vehicle, it is difficult to achieve stable fastening control.

  The present invention has been made paying attention to the above problems, and an object of the present invention is to provide a control device for an automatic transmission that can start without a sense of incongruity when the engine is restarted after an idle stop on an inclined road or the like.

  To achieve the above object, according to the present invention, an oil pump driven by an engine, a starting clutch fastened by a fastening pressure using the oil pump as a hydraulic source when the vehicle starts, and a state in which the starting clutch is disengaged from a released state. And the fastening pressure control means that performs the fastening pressure control through a plurality of phases, and when the vehicle is stopped and the predetermined condition is satisfied, the engine is stopped, and the predetermined condition is not satisfied. In an automatic transmission control device comprising an idle stop control means for restarting the engine and an engine control means for controlling the driving state of the engine, the rotational speed for detecting the value corresponding to the rotational speed of the drive wheels. It is determined whether the rotational speed detected by the rotational speed detection means immediately after restarting the engine and the engine speed is increased. And a road surface inclination judging means for judging that the road is a flat road when not rising, and a torque down control means for outputting to the engine control means a torque down amount for limiting an input torque of the engine according to the plurality of phases. And a torque down amount correcting means for correcting the torque down amount so as to increase when the road surface inclination determining means determines that the road is an inclined road.

  When the engine is restarted after idling stop, when it is determined that the road is on an inclined road, the torque-down amount is greatly corrected. Therefore, the start clutch can be engaged according to the inclined road, and the vehicle can start without a sense of incongruity. .

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

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

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

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

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

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

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

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

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

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

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

  Sensor signals from the steering angle sensor 12, the idle stop switch 13, the vehicle speed sensor 14, and the brake switch 15 are input to the idle stop control unit 17, and sensor signals, torque down control signals, and the like are mutually transmitted to the CVT control unit 9. Are communicating. When the idling stop control unit 17 determines that idling is stopped, a command to stop idling is output to the engine control unit 18. If it is determined that the engine is restarted after the idle stop, an engine restart command is output to the engine control unit 18, and the engine control unit 18 outputs a motor drive signal to the starter motor 19a. Start. Further, when the engine is restarted, a torque down amount corresponding to the engaged state of the forward clutch 25 is input, and the engine output state is controlled according to the torque down amount.

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

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

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

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

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

  Both the pressure regulator valve 40 and the clutch regulator valve 45 are regulated by the pressure modifier pressure. The pressure modifier pressure is a signal pressure that regulates the pressure modifier valve 73 supplied with the line pressure by the line pressure solenoid 72, and is regulated as a signal pressure higher than the signal pressure by the solenoids 70, 71, and 72. By adjusting the pressure by a signal pressure higher than the signal pressure by the solenoid 72, the pressure adjustment performance in the high pressure region is improved. On the other hand, the pressure regulated by the signal pressure by the solenoid 71 enables fine regulation in the low pressure region, but the maximum pressure that can be regulated is limited.

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

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

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

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

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

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

  In step 104, the engine 10 is stopped.

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

  In step 106, engine restart control is executed.

  That is, if the driver desires idle stop control, the vehicle is stopped, the brake is depressed, and the steering angle is 0, the engine is stopped. Here, the idle stop switch conveys the intention of the driver to execute or cancel the idle stop. This switch is energized when the ignition key is turned. The reason why the rudder angle is 0 is that, for example, idle stop is prohibited when the vehicle is temporarily stopped during traveling such as when turning right. Note that the idle stop permission flag is set by other control logic or the like, and is set when undesirable engine restart control cannot be achieved even when idle stop is performed. Specific examples include a case where the engagement control of the starting clutch 25 described later is not successful, and a case where the starter motor 19a cannot be driven due to insufficient charge amount of the battery, but is not particularly limited.

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

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

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

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

(Engine restart control)
Next, engine restart control will be described. FIG. 4 is a flowchart showing engine restart control in the first embodiment.

[Starter motor drive processing]
In step 201, it is determined whether or not the engine 19 has been completely detonated. If not, the process proceeds to step 202. If the detonation has been completed, the process proceeds to step 203. The complete explosion determination is not particularly limited as long as it is determined whether the engine speed is equal to or higher than a predetermined speed.
In step 202, a drive command is output to the starter motor 19a.
In step 203, a stop command for the starter motor 19a is output.

[Forward clutch engagement processing and torque down amount setting processing]
Next, forward clutch engagement control and torque down amount setting processing will be described. Basically, when the forward clutch 25 is engaged, the state until the clutch piston stroke ends by crushing the backlash or the disc spring of the clutch plate is defined as the precharge phase, and the clutch piston stroke ends, A state in which the clutch plate slip state is maintained is defined as an engagement phase, and a state in which the clutch plate slip is eliminated and the state shifts to complete engagement is defined as an engagement end phase.

  In step 301, it is determined whether or not the accelerator pedal is depressed. If it is depressed, the process proceeds to step 311. Otherwise, the process proceeds to step 302.

      (Forward clutch engagement control when accelerator pedal is OFF)

  In step 302, the select switching solenoid 70 is turned ON and the select switching valve 75 is switched.

  In step 303, the phase timer TF starts counting.

<Precharge phase processing>
In step 304, the engagement command value Ppre in the precharge phase is output to the lockup solenoid 71, and the engagement pressure is adjusted by the select control valve 90.
In step 305, it is determined whether or not the precharge time Tp has elapsed. If it has elapsed, the process proceeds to step 306. Otherwise, steps 304 to 305 are repeated.

<Fastening phase processing>
In step 306, the engagement command value Pcc in the engagement phase is set as an engagement pressure command value P (Vp) that achieves the shelf pressure advance speed Vp.
In Step 307, it is determined whether or not the fastening phase time Ts has elapsed. If it has elapsed, the process proceeds to Step 308. If not, Steps 306 to 307 are repeated.

<Ending phase process>
In step 308, the engagement pressure command value Pend in the engagement end phase is set.
In step 309, it is determined whether or not the fastening end phase time TL has elapsed. If it has elapsed, the process proceeds to step 310. Otherwise, steps 308 to 309 are repeated.

<Source pressure switching process>
In step 310, the select switching solenoid 70 is turned off.

      (Forward clutch engagement control when accelerator pedal is ON)

  In step 311, the select switching solenoid 70 is turned ON and the select switching valve 75 is switched.

  In step 312, the primary rotational speed Npri is read from the primary rotational speed sensor 4, and the turbine rotational speed Nt is read from the turbine rotational speed sensor 4a.

  In step 313, the phase timer TF starts counting.

<Precharge phase processing>
In step 314, the engagement command value Ppre in the precharge phase is output to the lockup solenoid 71, and the engagement pressure is adjusted by the select control valve 90.
In step 315, the torque reduction amount TDpre in the precharge phase is output to the engine control unit 18 to limit the input torque to the forward clutch 25. The torque down amount calculation process will be described later.
In step 316, it is determined whether or not the precharge time Tp has elapsed. If it has elapsed, the process proceeds to step 317. Otherwise, steps 314 to 316 are repeated.

<Fastening phase processing>
In step 317, the primary acceleration α is calculated.
In step 318, it is determined whether or not the primary rotational speed Npri read in step 312 has increased immediately after the brake pedal is turned off, specifically, whether or not the acceleration α of the primary rotational speed Npri is greater than the threshold value X. In the following cases, it is determined that the road is not an uphill road or a downhill road, and the process proceeds to step 318. Otherwise, the process proceeds to step 321.

(Fastening phase processing on flat road)
In step 319, the engagement command value Pcc in the engagement phase is set as an engagement pressure command value P (Vp) that achieves the shelf pressure advance speed Vp.
In step 320, the torque-down amount TDs in the engagement phase is output to the engine control unit 18 to limit the input torque to the forward clutch 25.
In step 321, it is determined whether or not the fastening phase time Ts has elapsed. If it has elapsed, the process proceeds to step 325, and if it has not elapsed, step 319 to step 321 are repeated.

(Conclusion phase processing on uphill or downhill roads)
In step 322, the engagement command value Pcc in the engagement phase is set as the engagement pressure command value P (Vp) that achieves the shelf pressure advance speed Vp.
In step 323, the torque down amount TDs (α) corresponding to the primary acceleration α is calculated based on the torque down amount map shown in FIG. 7, and TDs (α) is set as the torque down amount.
In step 324, it is determined whether or not the fastening phase time Ts has elapsed. If it has elapsed, the process proceeds to step 325, and if not, steps 322 to 324 are repeated.

<Ending phase process>
In step 325, the engagement command value Pcc in the engagement end phase is set to the engagement pressure command value Pend.
In step 326, the slip amount SLIP of the forward clutch 25, which is the difference between the turbine speed Nt and the primary speed Npri, is calculated.
In step 327, it is determined whether or not the slip amount SLIP is 0 (or less than the number of revolutions at which shock or the like does not cause a problem even if it is completely engaged). If it is 0, the process proceeds to step 328, otherwise steps 325 to 327 are performed. repeat. Note that the torque-down amount TDs or TDs (α) set in the engagement phase is continuously set as the torque-down amount.

<Source pressure switching process>
In step 328, the select switching solenoid 70 is turned OFF.
In step 329, the torque reduction amount TD is gradually released.

(Operation of forward clutch engagement processing and torque down amount setting processing)
Next, the operation based on the flowchart will be described. When the engine restart command is output, the starter motor 19a is driven in steps 201 to 203 to start the engine 19. In parallel with this operation, it is determined whether or not the accelerator pedal is ON. If the accelerator pedal is not depressed, the engine 19 maintains the idling speed so that no large torque is output, so the transition from the precharge phase to the engagement phase to the engagement end phase based on normal timer management Then, the forward clutch 25 is engaged.

  On the other hand, when the accelerator pedal is depressed, the engine output torque increases according to the accelerator opening. Here, when the hydraulic pressure necessary for fastening the forward clutch 25 is not sufficiently secured, when the input torque from the engine 19 is increased, the forward clutch slip state is prolonged, and the durability of the clutch plate is reduced. Start response delay will be caused. Therefore, when the accelerator pedal is depressed, a torque down amount TD is output to the engine control unit 18 to limit the input torque to the forward clutch 25. Hereinafter, the torque down amount setting logic will be described.

[Setting of torque reduction amount]
In the automatic transmission according to the first embodiment, the rotation of the engine output shaft 19b is amplified by the torque converter 1 and drives the turbine shaft 1a. Here, controlling the input torque to the forward clutch 25 means controlling the torque of the turbine shaft 1a.

Since the turbine torque Tt is determined by the engagement capacity of the forward clutch 25, the turbine torque Tt (Pcc) is estimated from the engagement pressure command value of the forward clutch 25. FIG. 6 is a diagram illustrating the relationship between the speed ratio e and the torque ratio t, which are values representing the characteristics of the torque converter 1. The target engine torque Te * that outputs this turbine torque Tt (Pcc) is
Speed ratio e = Nt / Ne Torque ratio t = Tt / Te
From the relationship
Te * = 1 / t ・ Tt (Pcc)
It becomes. The turbine speed is Nt, the engine speed is Ne, the turbine torque is Tt, and the engine torque is Te.

  Here, when the engine is restarted in a state where the forward clutch 25 is not engaged, since the turbine shaft 1a has only a load of the inertia of the turbine shaft itself, the turbine shaft 1a itself is also driven by the engine, and the turbine rotational speed Nt is It will increase. If the speed ratio e is calculated as the ratio between the engine speed Ne and the turbine speed Nt in this state, the speed ratio e is calculated as a very large value, and accordingly, the torque ratio t is also calculated to be small. That is, since the target engine torque Te * with respect to the turbine torque Tt is calculated to be large, the amount of torque reduction is also small, and the engine speed increases. Then, the slip state in the engagement phase of the forward clutch 25 does not converge, and there is a possibility that the durability is lowered and a time lag at the time of starting is caused.

  Therefore, in the torque reduction amount calculation process of the first embodiment, the calculation is performed using the primary rotation speed Npri instead of the turbine rotation speed Nt. Since the primary rotational speed Npri is a value related to the load of the vehicle, an accurate torque-down amount can be calculated. The torque down amount setting process based on the above logic will be described below.

FIG. 5 is a flowchart showing torque down amount setting processing.
In step 401, the engine speed Ne and the primary speed Npri are read.
In step 402, the speed ratio e = Npri / Ne is calculated.
In step 403, the torque ratio t (= Tt / Te) is read from the speed ratio-torque ratio map shown in FIG.
In step 404, an estimated turbine torque value Tt (Pcc) corresponding to the forward clutch engagement pressure command value Pcc is calculated.
In step 405, the turbine torque estimated value Tt (Pcc) in each phase is read, the target engine torque Te * corresponding to the turbine torque estimated value Tt (Pcc) is calculated, and the torque is reduced according to the target engine torque Te *. The quantity TD is output to the engine control unit 18.

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

  Here, when traveling forward on a flat road, it is possible to set the torque reduction amount based on the above logic. However, there is an aspect in which the above logic cannot be applied as it is when idling stops on the uphill road. Exists. Hereinafter, the operation during the uphill road and the downhill road will be described based on the time chart of FIG.

(Challenges on the uphill road)
After idling stop on the uphill road, the brake pedal is turned off and the engine 19 is restarted to start. Since the hydraulic pressure necessary for engaging the forward clutch 25 is not sufficiently secured at the initial stage of engine restart, the vehicle starts to reverse during that time. At this time, the primary rotational speed sensor 4 is rotated by the driving wheel in the direction opposite to the forward direction (hereinafter referred to as negative rotation). The primary rotational speed sensor 4 basically outputs a pulse signal from the concave and convex shape that rotates integrally with the primary pulley 30a, and only outputs a rectangular wave according to the rotational speed as the sensor signal. I can't recognize it.

  In this state, when the sensor signal is recognized as a forward rotation (hereinafter referred to as a forward rotation) and the torque reduction amount is controlled, the value of the speed ratio e as shown in the speed ratio-torque ratio map of FIG. As the engine speed increases, the torque ratio t becomes smaller, a larger value is calculated for the target engine torque Te *, and a smaller value is set as the torque reduction amount. However, as shown in FIG. 6, when viewed from the actual characteristics of the torque converter 1, when the speed ratio e is a negative value, the torque ratio t is a large value that is the same as when the speed ratio e = 0. . That is, from the state where the primary pulley 30a is rotated in the negative direction, the fastening capacity of the forward clutch 25 is gradually secured, and the torque reduction amount is calculated to be small until the one-way reverse stops and the forward start is started. There is a risk of exceeding the fastening capacity of 25.

(Challenges on downhill road)
Consider a case where the brake pedal is turned off and the engine 19 is restarted after starting idling on a downhill road. Although the hydraulic pressure necessary for fastening the forward clutch 25 is not sufficiently secured at the initial stage of engine restart, the vehicle starts to move forward due to gravity. At this time, the primary rotational speed sensor 4 is rotated in the same direction as the forward movement by the drive wheel.

  When the torque reduction amount is controlled in this state, the torque ratio t decreases as the speed ratio e increases, the target engine torque Te * is calculated to be a larger value, and the torque reduction amount is smaller. Will be set. However, since a gravitational acceleration component acts on the vehicle, a target engine torque Te * more than necessary is calculated. That is, there is a possibility that the engagement capacity required for the forward clutch 25 may be exceeded.

(Means for solving problems on uphill and downhill roads)
Therefore, in step 317, it is determined whether or not the primary rotational speed has increased immediately after the brake pedal is turned off. If it has increased, it is determined that the road is uphill or downhill. Specifically, it is determined whether or not the acceleration α of the primary rotational speed Npri is larger than the threshold value X. The engine torque that does not exceed the engagement capacity of the forward clutch 25 as much as possible is set by setting a large torque down amount TDs (α) corresponding to the primary acceleration α.

  If it is an uphill road, after the primary rotational speed Npri starts to rise, it will fall again with the state where the engagement capacity of the forward clutch 25 is gradually secured. The point at which a large torque ratio t actually acts is corrected according to the primary acceleration α at this time. On the other hand, on the downhill road, when the primary rotational speed Npri starts to increase, the rotational speed gradually increases regardless of the engagement capacity of the forward clutch 25. The point where the gravitational acceleration component acting on the vehicle is acting according to the primary acceleration α at this time is corrected. As a result, the forward clutch 25 does not continue to slip due to insufficient torque reduction, and the forward clutch 25 can be quickly engaged.

FIG. 8 is a time chart when the engine is restarted after idling stop. First, a description will be given based on a time chart on an uphill road.
When the brake pedal is turned off at time t1, engine restart control processing is started. At this time, the starter motor 19a is driven, and the line pressure rises by the oil pump 8. At this time, since the vehicle starts to move backward due to gravity, the primary rotational speed Npri starts to rise.
When the driver turns on the accelerator pedal at time t2, it is determined that there is an intention to start, and engagement control of the forward clutch 25 is started while requesting the engine control unit 18 for a torque reduction amount.
When the line pressure reaches a predetermined value at time t3, the precharge phase is started, and the torque down amount TDpre in the precharge phase is output.

When the precharge phase is completed at time t4, the engagement phase is started, and the torque reduction amount TDs in the engagement phase is output. With the start of the engagement phase, the engagement capacity of the forward clutch 25 gradually increases, and the primary rotation speed Npri gradually begins to decrease.
At time t5, when the torque down amount TDs (α) corresponding to the acceleration α of the primary rotational speed Npri becomes larger than the torque down amount TDs in the engagement phase, the torque down amount is switched to TDs (α) to limit the input torque. . This reduces the slip amount and avoids a state where the slip state cannot be converged.

When the engagement phase is completed at time t6, the slip amount SLIP, which is the rotational speed difference between the turbine rotational speed Nt and the primary rotational speed Npri, is not 0, so the torque down amount TDs (α) set at time t5 is continuously set. To do. In this way, the primary rotational speed Npri is quickly converged to 0 by increasing the engagement capacity of the forward clutch 25 while limiting the input torque from the engine 19.
When the slip amount SLIP becomes 0 at time t7, the source pressure of the engagement pressure supplied to the forward clutch 25 is switched. At this time, the torque-down amount TDs (α) is canceled, and the torque-down amount is gradually reduced to return to normal engine torque.

  Therefore, on the uphill road, the target engine torque Te * based on the torque converter characteristics can be accurately set by setting the torque reduction amount based on the change in the primary rotational speed Npri immediately after the brake pedal is turned off. As a result, the slip state of the forward clutch 25 can be quickly eliminated and the vehicle can start with good response.

  Next, the downhill road will be described. Since it is basically the same as the uphill road, only the differences will be described. On the downhill road, the primary rotational speed Npri continues to increase gradually. At this time, the target engine torque Te * is calculated to be smaller according to the primary acceleration α. As a result, a larger torque-down amount TDs (α) is set corresponding to the reduction in the load on the vehicle due to the gravitational acceleration component, so that the same effect as that on the uphill road can be obtained.

Hereinafter, the effects of the first embodiment will be listed.
(1) The primary acceleration α is detected from the primary rotational speed Npri, which is the value equivalent to the rotational speed of the drive wheel, and the vehicle moves due to the influence of the ramp immediately after the engine restarts depending on whether the primary acceleration α is greater than the threshold value X. Determine whether you are doing. When it was determined that the road was an inclined road, specifically, TDs was corrected to TDs (α) so that the amount of torque reduction was increased. As a result, the torque input to the forward clutch 25 can be accurately controlled, and the vehicle can start without a sense of incongruity.

  (2) The torque down amount TDs (α) is corrected according to the primary acceleration α from the torque down amount map. Accordingly, it is possible to set a torque reduction amount according to the slope, and it is possible to start without a sense of incongruity regardless of the slope of the slope.

  (3) The torque reduction amount TDs is controlled based on the torque ratio t of the torque converter 1 and the engagement capacity of the forward clutch 25. As a result, even if the influence of the characteristics of the torque converter 1 or the influence of the gravitational acceleration component of the vehicle occurs on an inclined road (uphill road, downhill road), it is possible to secure a sufficient amount of torque down, without a sense of incongruity. You can start.

  In the first embodiment, the belt type continuously variable transmission is applied as the automatic transmission. However, the present invention may be applied to a stepped automatic transmission, and is not particularly limited. Further, although the line pressure is detected as the hydraulic pressure detection means, the forward clutch pressure may be directly detected, or another hydraulic pressure related to the forward clutch pressure, for example, the secondary hydraulic pressure or the primary hydraulic pressure may be detected.

  Further, in the first embodiment, in step 317, the primary acceleration α is detected as a means for detecting an uphill road or a downhill road. Is the primary rotational speed Npri greater than the threshold value N within a certain time after the engine is started? You may judge by how. When the primary rotational speed Npri is larger than the threshold N, the torque down amount TD = TDs (N) is set as the torque down amount according to the primary rotational speed Npri. Set it to TDs.

It is a figure which shows the structure of the main unit of the vehicle provided with the belt-type continuously variable transmission in Example 1. FIG. 1 is a circuit diagram illustrating a configuration of a hydraulic circuit in Embodiment 1. FIG. 3 is a flowchart illustrating basic control of idle stop control according to the first embodiment. 3 is a flowchart illustrating engine restart control in the first embodiment. 3 is a flowchart illustrating torque down amount setting processing in the first embodiment. 3 is a map showing a relationship between a speed ratio and a torque ratio that are torque converter characteristics in the first embodiment. 3 is a map showing the relationship between primary acceleration and torque down amount in the first embodiment. 3 is a time chart showing a start time when the engine is restarted in the first embodiment.

Explanation of symbols

Engine 19
Oil pump 8
Forward clutch (start clutch) 25
Idle stop control unit (idle stop control means) 17
Line pressure sensor (hydraulic pressure detecting means) 16
Primary rotational speed sensor (rotational speed detection means) 4

Claims (5)

An oil pump driven by an engine;
A starting clutch fastened by a fastening pressure using the oil pump as a hydraulic source when the vehicle starts,
An engagement pressure control means for performing engagement pressure control through a plurality of phases when shifting from the released state of the starting clutch to the engaged state;
An idle stop control means for stopping the engine when the vehicle is stopped and when a predetermined condition is satisfied, and restarting the engine when the predetermined condition is not satisfied;
Engine control means for controlling the driving state of the engine;
In an automatic transmission control device comprising:
A rotational speed detection means for detecting a rotational speed equivalent value of the drive wheel;
A road surface that determines whether or not the rotational speed detected by the rotational speed detection means is increasing immediately after the engine is restarted. When the engine speed is increasing, the road surface is determined to be an inclined road. Inclination determination means;
Torque down control means for outputting to the engine control means a torque down amount for limiting engine input torque according to the plurality of phases;
A torque down amount correcting unit that corrects the torque down amount to be increased when the road surface inclination determining unit determines that the road is an inclined road;
A control device for an automatic transmission, characterized by comprising: The control apparatus for an automatic transmission according to claim 1,
An acceleration detection means for detecting an acceleration corresponding to the rotation speed of the drive wheel detected by the rotation speed detection means;
2. The automatic transmission control apparatus according to claim 1, wherein the torque down amount correcting means is means for correcting the torque down amount in accordance with the acceleration detected by the acceleration detecting means. The control apparatus for an automatic transmission according to claim 1 or 2,
The automatic transmission has a torque converter as a starting element,
The automatic transmission control apparatus according to claim 1, wherein the torque down amount determining means is means for controlling the torque down amount based on a torque ratio of the torque converter and an engagement capacity of the starting clutch. The control device for an automatic transmission according to any one of claims 1 to 3,
The road surface inclination determining means determines whether or not the rotational speed acceleration detected by the rotational speed detecting means immediately after the engine restart is equal to or greater than a predetermined value. A control device for an automatic transmission, characterized in that a means for judging a flat road is sometimes used. The control device for an automatic transmission according to any one of claims 1 to 3,
The road surface inclination determination means determines whether or not the rotation speed detected by the rotation speed detection means immediately after the engine is restarted is greater than or equal to a predetermined value. Is a means for determining a flat road, and is a control device for an automatic transmission.

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