JP2006038212A - Starting friction element control device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a starting friction element control device of a vehicle capable of improving starting acceleration performance in restarting, by shifting a continuously variable transmission up to the lower gear ratio, without causing an engine stall, even if a wheel locks in sudden braking. <P>SOLUTION: A transmission controller 41 controls an advance clutch 20, and can shift a speed to the low gear ratio side of a belt type continuously variable transmission mechanism 19, by transmitting a part of motive power of an engine 1 to the belt type continuously variable transmission mechanism 19, by putting the advance clutch 20 in a slip state, when the vehicle is put in a sudden braking state. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle start friction element control device that is mounted on a vehicle and controls fastening and release of a start friction element such as a start clutch provided between an engine and a continuously variable transmission.

As this type of technology, instead of a torque converter as a starting element, a starting clutch is provided between the belt type continuously variable transmission and the engine, and the starting clutch is engaged and released to transmit power between them. What is used as a starting element to block is known (for example, see Patent Document 1).
JP 2000-291773 A

  However, in the above prior art, if the starting clutch remains engaged when the wheel is locked during sudden deceleration due to sudden braking or a low friction coefficient (μ) road, the engine stops. May occur. Therefore, in such a case, when the starting clutch is released for the purpose of avoiding the engine stop, the power transmission from the engine side to the primary pulley is interrupted. If the power transmission to the primary pulley remains cut off, the rotational power of the primary pulley and the secondary pulley may not be sufficient, and the continuously variable transmission may not return to near the minimum gear ratio. Therefore, when the vehicle restarts, the vehicle can start only at the high speed side gear ratio, and there is a problem that the vehicle start acceleration performance may deteriorate.

  The present invention has been made paying attention to the above problems, and the object of the present invention is to prevent the engine from being stopped even if the wheels are locked during sudden braking or the like, and to reduce the continuously variable transmission at a lower speed. It is an object of the present invention to provide a vehicle start friction element control device capable of shifting to a ratio and improving the start acceleration performance at the time of restart.

  In order to achieve the above object, according to the present invention, in a starting frictional element control device that is installed in a vehicle and provided between an engine and a continuously variable transmission mechanism that transmits and cuts power between them, the vehicle is braked suddenly. A sudden braking determination means for determining whether or not the vehicle is in a state, and if the sudden braking determination means determines that the braking is in a sudden braking state, the starting friction element is set in a slip state and the starting friction element is moved to the engine side. Sudden braking control means that transmits a part of the power to the continuously variable transmission and enables the continuously variable transmission to shift to the low gear ratio side.

  In the vehicle start friction element control device of the present invention, even if the wheel is locked during sudden braking or the like, the engine is not stopped, and the continuously variable transmission is shifted to a lower gear ratio to start acceleration at the time of restart. It is possible to provide a vehicle starting friction element control device capable of improving performance.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out a vehicle starting friction element control apparatus according to the present invention will be described below with reference to the drawings.

  First, the configuration of the starting frictional element control device according to the first embodiment will be described.

  FIG. 1 is an overall system diagram showing the configuration of a drive system and a control system of a vehicle equipped with a belt-type continuously variable transmission equipped with a starting friction element control device according to the first embodiment.

  A vehicle equipped with a belt-type continuously variable transmission includes an engine 1, a forward / reverse switching mechanism 6 having a forward clutch 20 and a reverse brake 21 as a starting clutch, a belt-type continuously variable transmission mechanism 19 that performs a continuously variable transmission between input and output, An output gear 12 and a drive gear 13 for reducing the output, and left and right drive wheels 17 and 18 driven via a differential gear 14 and left and right drive shafts 15 and 16 are provided.

  The engine 1 is composed of a gasoline engine, a diesel engine, or the like, and the engine output shaft 2 is connected to the clutch input shaft 5 of the forward / reverse switching mechanism 6.

  The forward / reverse switching mechanism 6 includes a simple planetary gear 22 capable of switching the rotation direction and gear ratio, a forward clutch 20 that is fastened and constitutes a starting friction element of the present invention, and a forward friction that is fastened backward and is also of the present invention. And a reverse brake 21 as an element.

  The simple planetary gear 22 rotatably supports a sun gear 22s that rotates concentrically with the clutch output shaft 7, a plurality of pinions 22p that mesh with the sun gear 22s, a ring gear 22r that meshes with the pinion 22p, and the pinion. And a carrier 22c.

  The sun gear 22s is connected to the clutch output shaft 7 integral with the driven side portion of the forward clutch 20 and the primary pulley shaft. The carrier 22c is connected to the fixed side portion of the reverse brake 21. The ring gear 22r is connected to the drive side portion of the forward clutch 20 respectively.

  The forward clutch 20 has a plurality of plates interposed between a drive side portion connected to the clutch input shaft 5 and a driven side portion connected to the clutch output shaft 7. By applying clutch hydraulic pressure to a piston (not shown), the plates are pressed together so that power can be transmitted between the input and output. In addition, the clutch hydraulic pressure acting on the piston is discharged, so that the power cannot be transmitted to the output side portion. The forward clutch 20 is configured to be switchable between an engaged state and a released state.

  The reverse brake 21 has a plurality of plates interposed between an inner fixed portion of the transmission case 23 and a fixed side portion connected to the carrier 22c. By applying a brake hydraulic pressure to a piston (not shown), the plate is pressed to be in a fastening state in which the integral carrier 22c is fixed to the fixed side portion in a non-rotatable manner. Further, the brake hydraulic pressure acting on the piston is discharged, so that the fixed side portion and the carrier 22c are brought into a released state in which the portion can be rotated. The reverse brake 21 is configured to be switchable between an engaged state and a released state.

  The belt-type continuously variable transmission mechanism 19 changes the speed ratio between the input and output shafts continuously. A primary pulley 8 connected to a primary pulley shaft integral with the clutch output shaft 7, a secondary pulley 10 connected to a secondary pulley shaft 11, a CVT belt 9 spanned between the primary pulley 8 and the secondary pulley 10, It has.

  The primary pulley 8 and the secondary pulley 10 have fixed sheaves 8a and 10a, movable sheaves 8b and 10b that approach and leave the fixed sheaves 8a and 10a, respectively. A primary pulley oil chamber 33 is provided on the back surface of the movable sheave 8 b of the primary pulley 8. The hydraulic pressure supplied to the primary pulley oil chamber 33 is controlled by the hydraulic pressure control unit 32 so that the movable sheave 8b is moved relative to the stationary sheave 8a so as to approach and separate from the fixed sheave 8a. The hydraulic pressure control unit 32 is supplied with pressure oil obtained by the oil pump 31 sucked from the oil tank 30.

  Next, the control system of the vehicle equipped with the belt type continuously variable transmission according to the first embodiment will be described with reference to FIG.

  This control system includes an engine controller 40 that electronically controls the engine 1, a transmission controller 41 that electronically controls a hydraulic control unit 32 connected to the forward / reverse switching mechanism 6 and the belt-type continuously variable transmission mechanism 19, a transmission controller 41, Sensors connected to the engine controller 40.

  The engine controller 40 is connected to an engine speed sensor 42 that detects the rotational speed of the engine output shaft 2 and an accelerator opening sensor 43 that detects the degree of depression of the accelerator pedal. Engine speed information and accelerator opening information are input from the engine rotation sensor 42 and accelerator opening sensor 43, respectively. These engine speed information and accelerator opening information are also input from the engine controller 40 to the transmission controller 41.

  The transmission controller 41 includes a select lever sensor 44 that detects the position of the select lever, a vehicle speed sensor 45 that detects the vehicle speed, an input rotational speed sensor 46 that detects the rotational speed of the clutch input shaft 5 of the forward / reverse switching mechanism 6, and the front and rear An output rotational speed sensor 47 for detecting the rotational speed of the clutch output shaft 7 of the advance switching mechanism 6 is connected. From these, select lever position information, vehicle speed information, input rotational speed information, output rotational speed information, and the like are input.

  The transmission controller 41 is connected to a forward clutch solenoid 48 that controls the hydraulic pressure supplied to the forward clutch 20 and a reverse brake solenoid 49 that controls the hydraulic pressure supplied to the reverse brake 21. The transmission controller 41 controls the forward clutch solenoid 48 and the reverse brake solenoid 49 based on information from the sensors. By this control, the forward clutch 20 and the reverse brake 21 are switched to a completely engaged state, a slip state, and a released state, respectively.

  The transmission controller 41 further controls the hydraulic pressure supplied to the primary pulley oil chamber 33 by a solenoid valve (not shown) provided in the hydraulic pressure control unit 32.

  An output gear 12 is fixed to an end portion of the secondary pulley shaft 11 on the secondary pulley 10 side of the belt type continuously variable transmission mechanism 19, and meshed with a drive gear 13 having a larger diameter than the output gear 12.

  Two pinions of the differential gear 14 are fixed to the drive gear 13, and side gears are engaged with these pinions from the left and right, respectively. Drive shafts 15 and 16 are connected to the side gears to drive the left and right drive wheels 17 and 18.

  Next, the operation will be described.

[When the vehicle is stopped]
When the engine 1 is stopped, the oil pump 31 is not driven and no hydraulic pressure is generated. Further, since the hydraulic control unit 32 is not in the forward or reverse traveling state, both the forward clutch 20 and the reverse brake 21 are in a released state, and the belt type continuously variable transmission mechanism 19 is also in a state where power cannot be transmitted. .

  When the engine 1 is operating, the oil pump 31 is driven to supply pressure oil to the hydraulic control unit 32. At this time, the engine controller 40 controls the engine 1 based on the accelerator opening information input from the accelerator opening sensor 43, the engine speed information input from the engine speed sensor 42, and the like.

  The hydraulic control unit 32 does not supply pressure oil to the forward clutch 20 and the reverse brake 21 when a select lever (not shown) is in a non-traveling position such as a P (park) position or an N (neutral) position. Continue to release. Therefore, the driving force of the clutch input shaft 5 is not transmitted to the clutch output shaft 7, and the belt type continuously variable transmission mechanism 19 is not rotated. As a result, the driving force does not act on the driving wheels 17 and 18.

  During the operation of the engine 1, this power is transmitted to the clutch input shaft 5 after the vibration is attenuated by the torsional damper 3. The power here is substantially equivalent to the engine torque.

[When the vehicle starts]
When the engine 1 is in an operating state and the select lever is moved from a non-travel position to a forward travel position such as a D (drive) position, the transmission controller 41 switches a valve (not shown) in the hydraulic control unit 32. Then, control is performed so as to start supplying pressure oil to the forward clutch 20. At this time, the magnitude of the hydraulic pressure supplied to the forward clutch 20 is initially set to a hydraulic pressure lower than the complete engagement pressure until a predetermined time elapses as will be described later, and the forward clutch 20 is brought into a slip state. As a result, a part of the motive power output from the engine is changed to heat while the remaining motive power is output to the clutch output shaft 7 while avoiding the engagement shock caused by the forward clutch 20 being rapidly engaged at a high pressure.

  In this state, the forward clutch 20 is slipping. Therefore, the clutch output shaft 7 directly coupled to the sun gear 22s of the forward / reverse switching mechanism 6 and the driven side portion of the forward clutch 20 is rotated slower than the ring gear 22r of the forward / reverse switching mechanism 6 by the amount of the slip, and the transmission power is also increased. It is getting smaller.

  The power transmitted to the clutch output shaft 7 in this way is further transmitted to the belt type continuously variable transmission mechanism 19. Here, the motor is decelerated and output to the secondary pulley shaft 11, and then is transmitted to the drive wheels 17 and 18 through the output gear 12, drive gear 13, differential gear 14, and drive shafts 15 and 16 in this order. As a result, the vehicle starts and moves forward. In this forward travel position, no pressure oil is supplied to the reverse brake 21, and the reverse brake 21 is in a released state.

  After the first predetermined time has elapsed since the start of the slip control, the transmission controller 41 calculates the input / output rotational speed difference of the forward clutch 20. This input / output rotation speed difference is calculated based on the clutch input shaft rotation information obtained from the input rotation speed sensor 46 and the clutch output shaft rotation information obtained from the output rotation speed sensor 47. The hydraulic pressure supplied to the forward clutch 20 is gradually raised in accordance with the difference between the input and output rotational speeds, and is controlled to a fully engaged state in which the clutch does not slip eventually, that is, the clutch engaging torque is equal to or greater than the engine torque.

  On the other hand, when the select lever is moved from the non-traveling position to the R (reverse) position, the transmission controller 41 switches the valve in the hydraulic control unit 32 to a pressure lower than the hydraulic pressure required for complete engagement with the reverse brake 21. Oil is supplied until a second predetermined time has elapsed. As a result, the reverse brake 21 slips and transmits the remaining power to the clutch output shaft 7 while changing a part of the power output from the engine 1 into heat.

  That is, in this state, the carrier 22c rotates with the brake applied, so that a part of the power transmitted from the engine 1 to the clutch input shaft 5 and the ring gear 22r integrated therewith moves backward via the carrier 22c. The brake 21 is brought into a slip state. The remaining power is transmitted from the ring gear 22r to the sun gear 22s via the pinion 22p. The rotation direction of the sun gear 22s is opposite to the rotation direction of the clutch input shaft 5. The power transmitted to the sun gear 22s is transmitted to the drive wheels 17 and 18 via the clutch output shaft 7, the belt type continuously variable transmission mechanism 19 and the like. In this reverse position, no hydraulic pressure is supplied to the forward clutch 20, and the forward clutch 20 is in a released state.

  Even at the time of reverse, the hydraulic pressure supplied to the reverse brake 21 is gradually raised after the second predetermined time has elapsed since the start of slip control, as in the case of forward start. It is concluded.

[When the vehicle is running after starting]
As described above, when the first predetermined time elapses after starting at the forward travel position, the transmission controller 41 controls the valve of the hydraulic control unit 32 to change the hydraulic pressure supplied to the forward clutch 20 to the clutch input / output rotational speed difference. Increase according to. Finally, the forward clutch 20 is brought into a fully engaged state without slip so that the clutch engagement torque in the forward clutch 20 becomes equal to or higher than the engine torque.

  In this state, the sun gear 22s of the forward / reverse switching mechanism 6 has the same rotational speed as that of the ring gear 22r, and these rotate together with the carrier 22c. Therefore, the clutch output shaft 7 rotates in the same direction and at the same rotational speed as the clutch input shaft 5, and the power of the engine 1 is input to the belt type continuously variable transmission mechanism 19 as it is.

  The transmission ratio of the belt-type continuously variable transmission mechanism 19 is controlled by the transmission controller 41. That is, the target gear ratio is determined based on vehicle speed information obtained from the vehicle speed sensor 45 by the transmission controller 41, accelerator opening information obtained from the engine controller 40, engine speed information, and the like. The hydraulic pressure supplied to the primary pulley oil chamber 33 is adjusted so as to achieve this target gear ratio, and the movable sheaves of the primary pulley 8 and the secondary pulley 10 are displaced.

  The output of the belt-type continuously variable transmission mechanism 19 obtained according to the gear ratio is transmitted to the left and right drive wheels 17, 18 via the output gear 12, the drive gear 13, the differential gear 14, and the drive shafts 15, 16. Drive wheels 17 and 18 are driven to drive the vehicle forward.

  On the other hand, even during reverse travel, when the second predetermined time elapses while the reverse brake 21 is slipped, the transmission controller 41 controls the valve of the hydraulic control unit 32 to clutch the hydraulic pressure supplied to the reverse brake 21. Increase according to the input / output rotational speed difference. Finally, the reverse brake 21 is brought into a completely engaged state without slip so that the brake torque at the reverse brake 21 becomes equal to or higher than the engine torque.

  In this completely engaged state, the power input from the engine 1 as it is is transmitted to the ring gear 22 r of the forward / reverse switching mechanism 6 connected to the clutch input shaft 5. The power transmitted to the ring gear 22r causes the pinion 22p to rotate on the carrier 22c fixed so as not to rotate, and the sun gear 22s meshing with the pinion 22p is increased and reversely rotated. This reversed output is input to the belt type continuously variable transmission mechanism 19 and transmitted to the drive wheels 17 and 18 as in the case of the forward traveling, although the rotational direction is different.

[Vehicle sudden braking]
If the driving wheels 17 and 18 are locked during sudden braking of the vehicle and the starting clutch remains engaged, the engine may stop due to a load from the driving wheels 17 and 18 side. Therefore, in such a case, when the starting clutch is released for the purpose of avoiding the engine stop, the power transmission from the engine side to the primary pulley is interrupted. If power transmission to the primary pulley remains interrupted, the rotational power of the primary pulley and secondary pulley may not be sufficient, and the belt-type continuously variable transmission mechanism 19 may not return to near the minimum gear ratio. . Therefore, when the vehicle restarts, the start acceleration performance of the vehicle, which can start only at the high speed side gear ratio, may deteriorate.

  Therefore, in this embodiment, the starting clutch is released when the vehicle is suddenly braked and the rotational speeds of the drive wheels 17 and 18 are below a predetermined value. The predetermined value is, for example, a state in which the rotational speed of the drive wheels 17 and 18 is locked or extremely low, and the engine wheels may be stopped if the start clutch remains engaged. The number of revolutions. In the following description, the predetermined value is set assuming that the rotational speed of the drive wheels 17 and 18 is zero, that is, when the drive wheels 17 and 18 are locked.

  When the drive wheels 17 and 18 start to rotate again, the starting clutch is engaged to transmit power to the belt type continuously variable transmission mechanism 19.

  FIG. 2 is a flowchart showing the flow of the start friction element control process executed by the transmission controller 41 during sudden braking of the vehicle. Each step will be described below. Although only the start control of the forward clutch 20 will be described here, the same control logic as that of the forward clutch start control is basically used for the reverse brake 21 as well.

  In step S1, it is determined whether or not the vehicle is suddenly braked from the information of the vehicle speed sensor 45. If the vehicle is suddenly braked, the process proceeds to step S2. If the vehicle is not suddenly braked, the process is performed. finish.

  In step S2, when sudden braking is started, it is determined whether or not the drive wheels 17 and 18 are rotating. If YES, the process proceeds to step S2, and if NO, the process proceeds to step S3.

  In step S3, if the drive wheels 17 and 18 are rotating, the clutch engagement torque Tc is set to the prescribed clutch torque T1, and the process returns to step S1. This prescribed clutch torque T1 is a value that can transmit the maximum torque that does not cause engine stop in idle control. At this time, the forward clutch 20 is in a slip state. In step S3, the slip control process is executed while the drive wheels 17 and 18 are rotating. When the drive wheels 17 and 18 are locked, the process proceeds to step S4, the forward clutch 20 is released, and the process ends.

  Steps S2 to S4 correspond to the sudden braking control means of the present invention.

  FIG. 3 is a time chart showing the relationship between the vehicle speed from the start of sudden braking of the vehicle to the stop of the vehicle, the speed ratio of the continuously variable transmission, and the clutch torque in the process of the above flowchart.

As shown in FIG. 3, the drive wheels 17 and 18 are rotating during the time t ₁ -t _2, during the time t ₃ -t _{4, and} during the time t ₅ -t _6, so that the clutch torque is increased to the specified clutch torque T1. Let As the clutch torque increases, rotational power is applied to the primary pulley 8 and the secondary pulley 10 of the belt-type continuously variable transmission mechanism 19, and the speed of the belt-type continuously variable transmission mechanism 19 is changed to increase the gear ratio, resulting in a lower speed side. .

On the other hand, the drive wheels 17 and 18 do not rotate during the time t ₀ -t ₁ , t ₂ -t ₃ , and t ₄ -t ₅ , so the forward clutch 20 is released.

  With this action, power can be transmitted to the belt-type continuously variable transmission mechanism 19 to return to the vicinity of the minimum speed ratio while avoiding engine stop during sudden braking of the vehicle.

  Next, the effect of the present embodiment will be described.

  (1) At the time of sudden braking of the vehicle, when the drive wheels 17 and 18 are rotating, the forward clutch 20 is engaged in a slip state and a part of power is transmitted to the belt type continuously variable transmission mechanism 19. Therefore, the belt-type continuously variable transmission mechanism 19 can be shifted to the low speed ratio side when the vehicle is stopped, compared to the state in which the forward clutch 20 is completely released at the time of sudden braking of the vehicle. , The acceleration of vehicle start is improved.

  (2) During sudden braking of the vehicle, when the drive wheels 17 and 18 are rotating, the forward clutch 20 is engaged with a clutch torque T1 that can transmit the maximum torque without stopping the engine. Therefore, the power can be transmitted to the belt type continuously variable transmission mechanism 19 while avoiding the engine stop, and the continuously variable transmission can be shifted to the lower speed ratio side. Therefore, since the vehicle can start at a lower speed ratio when the vehicle restarts after the vehicle stops, the start acceleration of the vehicle is improved.

  (3) During sudden braking of the vehicle, if the drive wheels 17 and 18 are not more than a predetermined value, for example, if the drive wheels 17 and 18 are not rotating, the forward clutch 20 is inhibited and the forward clutch 20 is released. I made it. Therefore, when the drive wheels 17 and 18 are locked and the secondary pulley 10 of the belt type continuously variable transmission mechanism 19 cannot be rotated, the forward clutch 20 is released from the slip state, thereby preventing deterioration of fuel consumption due to an increase in load. can do.

  In other words, during deceleration with the accelerator pedal returned, a fuel cut is made on the engine 1 when engine speed> recovery speed. When engine speed ≦ recovery speed, the engine enters idle control for injecting fuel so as to maintain idle speed.

  During the slip control of the forward clutch 20, the engine 1 injects fuel so that the engine speed does not fall below the recovery speed. Therefore, if the slip control is continued even when the drive wheels 17 and 18 are locked, the belt type continuously variable transmission mechanism 19 will continue to inject fuel despite the inability to shift, resulting in wasteful fuel blowing. Become. In the first embodiment, since slip control is prohibited when the wheel speed is substantially zero, it is possible to minimize deterioration in fuel consumption due to this slip control.

  (4) The determination that the rotational speeds of the drive wheels 17 and 18 are equal to or lower than the predetermined value is based on the determination of the wheel lock in the antilock brake system. Therefore, the judgment information from the antilock brake system can be used as it is, and the antilock brake control of the antilock brake system and the slip control of the forward clutch 20 can be linked. Therefore, it is possible to efficiently downshift.

  These effects can be similarly obtained when the reverse brake 21 is used.

  The overall system of the vehicle equipped with a belt type continuously variable transmission provided with the starting friction control device of this embodiment is the same as that of the first embodiment, but the control is different. That is, when the vehicle is suddenly braked and the drive wheels 17 and 18 are rotating, the transmission controller 41 controls the clutch torque of the forward clutch 20 as a value corresponding to the engine speed. In addition, about the structure similar to Example 1, the code | symbol same as Example 1 is attached | subjected and those description is abbreviate | omitted.

  Next, the operation will be described.

  In order to shift the belt type continuously variable transmission mechanism 19 to the low speed ratio side when the vehicle is stopped, the clutch torque of the forward clutch 20 is when the drive wheels 17 and 18 are rotating and the engine speed is high. It is necessary to increase power to transmit power to the belt type continuously variable transmission mechanism 19 side. However, even when the drive wheels 17 and 18 are not locked, there is a risk that the engine will stop when the engine 1 is subjected to slip control and a load is applied to the engine 1 when the engine speed is low.

  Therefore, in this embodiment, when the drive wheels 17 and 18 are rotating and the engine speed is equal to or higher than a predetermined value, the clutch torque of the forward clutch 20 is controlled according to the engine speed. did. Further, the forward clutch 20 is released when the engine speed is smaller than a predetermined value.

  FIG. 4 is a flowchart showing the flow of the starting clutch control process executed by the transmission controller 41 when the vehicle is suddenly braked in this embodiment. Each step will be described below. Although only the start control of the forward clutch 20 will be described here, the same control logic as that of the forward clutch start control is basically used for the reverse brake 21 as well.

  In step S11, it is determined whether or not the vehicle is suddenly braking from the information of the vehicle speed sensor 45. If the vehicle is suddenly braked, the process proceeds to step S12. If the vehicle is not suddenly braked, the process is performed. finish.

  In step S12, when sudden braking is started, it is determined whether or not the drive wheels 17 and 18 are rotating. If YES, the process proceeds to step S13, and if NO, the process proceeds to step S14.

  In step S13, if the drive wheels 17 and 18 are rotating, a clutch torque corresponding to the engine speed is set. When the engine speed is smaller than the predetermined engine speed n1, the clutch torque is zero, that is, the forward clutch 20 is released and the slip control of the forward clutch 20 is not performed. When the rotational speed is equal to or higher than the predetermined rotational speed n1, the clutch torque is transmitted so that torque that does not stop the engine is transmitted to the engine 1 according to the rotational speed of the engine. The predetermined rotational speed n1 is a rotational speed that may cause the engine to stop when a load is applied to the engine, and is calculated in advance through experiments or calculations.

  When the clutch torque is set, the process returns to step S12 to determine again whether or not the drive wheels 17 and 18 are rotating. If the drive wheels 17 and 18 are rotating, the clutch torque corresponding to the engine speed at that time is set. As the engine speed increases, the clutch torque of the forward clutch 20 is increased so that the belt-type continuously variable transmission mechanism 19 can quickly shift to the low speed side.

  In step S14, if the drive wheels 17 and 18 are locked, the clutch torque is released and the process ends.

  Due to this action, when the drive wheels 17 and 18 are rotating during the sudden braking of the vehicle, more power can be transmitted to the belt type continuously variable transmission mechanism 19 according to the engine speed, and the speed is shifted to the low speed ratio side. be able to. When the engine speed is smaller than the predetermined speed n1, the forward clutch 20 is released, so that it is possible to avoid engine stop during sudden braking of the vehicle.

  Next, the effect of the present embodiment will be described.

  (5) When the drive wheels 17 and 18 are rotating during the sudden braking of the vehicle, the forward clutch 20 is engaged with a clutch torque corresponding to the engine speed. Therefore, a large driving force can be transmitted to the belt-type continuously variable transmission mechanism 19, and the belt-type continuously variable transmission mechanism 19 can be shifted to the lower speed ratio side.

  Further, during the sudden braking of the vehicle, when the driving wheels 17 and 18 are not more than a predetermined value, for example, when the driving wheels 17 and 18 are not rotating, the forward clutch 20 is released by prohibiting the slip control of the forward clutch 20. did. Therefore, when the drive wheels 17 and 18 are locked and the secondary pulley 10 of the belt type continuously variable transmission mechanism 19 cannot be rotated, the forward clutch 20 is released from the slip state, thereby preventing deterioration of fuel consumption due to an increase in load. can do.

  (6) When the drive wheels 17 and 18 are rotating during the sudden braking of the vehicle, the clutch torque of the forward clutch 20 is reduced as the engine speed is smaller, and the transmission to the belt type continuously variable transmission mechanism 19 is performed. Reduce the torque. Therefore, even when the engine speed is small, the belt-type continuously variable transmission mechanism 19 can be shifted to the lower speed ratio side while avoiding engine stop.

  (7) When the engine speed is smaller than the predetermined speed n1, the forward clutch 20 is released so that the forward clutch 20 is not slipped. Therefore, no load is applied to the engine 1 and the engine stop can be avoided.

  The overall system of the vehicle equipped with a belt type continuously variable transmission provided with the starting friction control device of this embodiment is the same as that of the first embodiment, but the control is different. That is, during sudden braking of the vehicle, the transmission controller 41 controls the clutch torque of the forward clutch 20 as a value corresponding to the engine speed. In addition, about the structure similar to Example 1, the code | symbol same as Example 1 is attached | subjected and those description is abbreviate | omitted.

  Next, the operation will be described.

  In order to shift the belt-type continuously variable transmission mechanism 19 to the low speed ratio side when the vehicle is stopped, the clutch torque of the forward clutch 20 is controlled according to the engine speed even during sudden braking of the vehicle, and the belt-type continuously variable transmission mechanism. It is necessary to transmit power to the 19th side. Further, if the forward clutch 20 is completely released during the sudden braking of the vehicle, the slip control of the forward clutch 20 starts after the clutch torque of the forward clutch 20 starts to be increased when reacceleration is performed during the sudden braking of the vehicle. It takes time to be done.

  Therefore, in this embodiment, when the engine speed is greater than or equal to a predetermined value, the clutch torque of the forward clutch 20 is increased according to the engine speed. Further, when the engine speed is smaller than a predetermined value, the forward clutch 20 is engaged with a clutch torque that does not stop the engine.

  FIG. 5 is a flowchart showing the flow of the start clutch control process executed by the transmission controller 41 when the vehicle is suddenly braked in the present embodiment. Each step will be described below. Although only the start control of the forward clutch 20 will be described here, the same control logic as that of the forward clutch start control is basically used for the reverse brake 21 as well.

  In step S21, it is determined whether or not the vehicle is suddenly braked from the information of the vehicle speed sensor 45. If the vehicle is suddenly braked, the process proceeds to step S22. If the vehicle is not suddenly braked, the process is performed. finish.

  In step S22, when sudden braking is started, a clutch torque corresponding to the engine speed is set. When the engine speed is smaller than the predetermined engine speed n2, the clutch torque is set to a constant value T1 regardless of the engine speed. When the engine speed is equal to or higher than the predetermined engine speed n2, the smaller the engine speed, the smaller the clutch torque is set to avoid engine stop. The clutch torque T2 is a value at which the load applied to the engine 1 does not stop regardless of the engine speed when the forward clutch 20 is engaged with the clutch torque T2, and is calculated in advance by experiment or calculation.

  Due to this action, the forward clutch 20 is not completely released during the sudden braking of the vehicle, so that even when reacceleration is performed during the sudden braking of the vehicle, slip control of the clutch torque of the forward clutch 20 is immediately started.

  Next, the effect of the present embodiment will be described.

  (8) Since the forward clutch 20 is engaged with the clutch torque corresponding to the engine speed during the sudden braking of the vehicle, the load transmitted from the drive wheels 17 and 18 to the engine 1 can be controlled according to the engine speed. Therefore, since the forward clutch 20 is not completely released while avoiding the engine stop, the slip torque control of the forward clutch 20 is immediately started even when re-acceleration is performed during the sudden braking of the vehicle. Acceleration response is improved.

  (9) During sudden braking of the vehicle, the clutch torque is reduced as the engine speed decreases, so the load transmitted from the drive wheels 17 and 18 to the engine 1 is also reduced. Therefore, power can be transmitted to the belt type continuously variable transmission mechanism 19 while avoiding engine stop.

  (10) During sudden braking of the vehicle, when the engine speed is smaller than the predetermined speed n2, the clutch torque of the forward clutch 20 is set to the clutch torque T2 for stopping the engine regardless of the engine speed.

  The vehicle starting clutch control device of the present invention has been described based on the first embodiment. However, the specific configuration is not limited to these embodiments, and the claims relate to each claim. Design changes and additions are allowed without departing from the spirit of the invention.

  In the first to third embodiments, the start clutch control system is applied to the engagement control of the forward clutch and the reverse brake of the vehicle equipped with the belt type continuously variable transmission, but the vehicle equipped with the stepped automatic transmission or the toroidal type is shown. The present invention can be applied to various vehicles including a continuously variable transmission-equipped vehicle, an automatic MT-equipped vehicle, a hybrid vehicle, an electric vehicle, and the like that have a clutch that is engaged at the time of starting and transmits input torque from a drive source.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall system diagram showing a drive system and a control system of a vehicle equipped with a belt type continuously variable transmission to which a starting friction element control device according to a first embodiment is applied. 3 is a flowchart illustrating a flow of a starting friction element control process executed by a transmission controller according to the first embodiment. 4 is a time chart of the conventional starting friction element control and the starting clutch control according to the first embodiment. 12 is a flowchart illustrating a flow of a starting friction element control process executed by a transmission controller according to a second embodiment. 12 is a flowchart illustrating a flow of a starting friction element control process executed by a transmission controller according to a third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 6 Forward / reverse switching mechanism 19 Belt type continuously variable transmission mechanism 20 Forward clutch 21 Reverse brake 41 Transmission controller

Claims (10)

In a vehicle start friction element control device that is installed in a vehicle and provided between an engine and a continuously variable transmission mechanism, and that transmits and blocks power between them,
Sudden braking determination means for determining whether or not the vehicle is in a sudden braking state;
If it is determined by the sudden braking determination means that the sudden braking state is in effect, the starting friction element is brought into a slip state, and a part of the engine-side power is transmitted to the starting friction element to the continuously variable transmission. Sudden braking control means for enabling the continuously variable transmission to shift to a low gear ratio side;
A starting friction element control device for a vehicle, comprising: The vehicle starting friction element control device according to claim 1,
The sudden braking control means controls the slip state so that the starting friction element can transmit the maximum torque at which engine stop does not occur in idle control. In the vehicle starting friction element control device according to claim 1 or 2,
When the sudden braking control means determines that the rotational speed of the drive wheels connected to the continuously variable transmission has become a predetermined value or less, the control means for prohibiting the control of bringing the starting friction element into a slip state is prohibited. A vehicle starting friction element control device. The starting friction element control device for a vehicle according to claim 3,
The vehicle starting friction element control device according to claim 1, wherein the determination that the rotational speed of the driving wheel is equal to or lower than a predetermined value is based on a determination of wheel locking in an anti-lock brake system. The starting friction control device for a vehicle according to claim 1,
When the sudden braking control means determines that the rotational speed of the drive wheels connected to the continuously variable transmission has become a predetermined value or less, the control means prohibits the control of bringing the starting friction element into a slip state, When it is determined that the rotational speed of the drive wheel is greater than a predetermined value, the starting friction element is controlled to the slip state so that the starting friction element can transmit torque according to the engine speed. A starting friction element control device for a vehicle. The vehicle start friction control device according to claim 5,
When the sudden braking control means determines that the rotational speed of the drive wheel connected to the continuously variable transmission is larger than a predetermined value, the starting friction element can transmit a smaller torque as the engine speed is smaller. A starting friction element control device for a vehicle, wherein the slip state is controlled so as to become. The vehicle start friction control device according to claim 6,
The vehicle start friction element control device according to claim 1, wherein the sudden braking control means prohibits the control of making the start friction element slip when the engine speed is smaller than a predetermined value. The starting friction control device for a vehicle according to claim 1,
The vehicle start friction element control device according to claim 1, wherein the sudden braking control means controls the slipping state so that the start friction element can transmit a torque according to an engine speed. The vehicle start friction control device according to claim 8,
The sudden braking control means controls the slip state so that the starting friction element can transmit a smaller torque as the engine speed is smaller. The vehicle start friction control device according to claim 9,
The sudden braking control means controls the slip state so that when the engine speed is smaller than a predetermined value, the starting friction element can transmit a predetermined torque regardless of the engine speed. A starting friction element control device for a vehicle.

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