JP2005164000A - Speed change control device of continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress vehicle noise and improve fuel consumption performance by adequately canceling an acceleration mode depending on a travelling condition of a vehicle. <P>SOLUTION: The continuously variable transmission includes a primary pulley and a secondary pulley and executes variable speed change by changing a pulley groove width. When a normal speed change mode is switched to an acceleration mode by pushing an accelerator at a status point P1, a target primary rotational speed Np is set on the basis of an acceleration map. Then, when an actual primary rotational speed reaches to the target primary rotational speed Np3 through a status point P2, speed change control along a characteristic line TV3' of the acceleration map is executed. This speed change control is executed until a hold time Th passes, and the acceleration mode is canceled after the hold time Th passes. Thereby, a rotation increase of the target primary rotational speed Np is suppressed, and the vehicle noise is suppressed and the fuel consumption performance is improved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a shift control device for a continuously variable transmission mounted on a vehicle.

  The continuously variable transmission (CVT) mounted in the power transmission system of the vehicle includes a belt type continuously variable transmission and a toroidal type continuously variable transmission. In any transmission, the gear ratio depends on the driving state. Automatically controlled. The belt-type continuously variable transmission includes a primary pulley provided on an input shaft, a secondary pulley provided on an output shaft, and a drive belt stretched over these pulleys, and changes a winding diameter of the drive belt. Thus, the rotation of the input shaft can be transmitted to the output shaft while changing the gear ratio steplessly. The toroidal continuously variable transmission includes an input disk provided on the input shaft, an output disk provided on the output shaft, and a power roller that contacts the input disk and the output disk facing each other. By changing the contact radius of the power roller to the gear ratio, the transmission gear ratio can be changed steplessly.

  These continuously variable transmission control devices are provided with a shift characteristic map that is set based on simulations and tests, and by referring to the shift characteristic map based on the throttle opening, the vehicle speed, etc. Set the target rotational speed of the input disc. Then, the target transmission ratio is set from the target rotational speed, and a drive signal corresponding to the target transmission ratio is output to the continuously variable transmission, so that the transmission control of the continuously variable transmission is performed according to the running state of the vehicle. Execute. Further, in order to improve the power performance of the vehicle in the acceleration mode, a shift control device including a shift characteristic map in which the target rotational speed is set to the high rotation side in addition to the shift characteristic map used in normal times has been developed. .

As described above, the plurality of shift characteristic maps provided in the shift control device are switched according to the accelerator opening and the accelerator opening speed, so that the acceleration mode is maintained until the accelerator pedal is largely returned. For this reason, even if the initial acceleration request is satisfied, depending on the return state of the accelerator pedal, the target rotational speed may be maintained high without being released from the acceleration mode. In view of this, a shift control device for a continuously variable transmission has been developed in which the opening threshold value that is compared with the accelerator opening amount when the acceleration mode is released is changed according to the traveling state of the vehicle (for example, Patent Documents). 1). According to this speed change control device, the acceleration mode can be canceled accurately according to the decrease in the driver's acceleration request, and the uncomfortable feeling given to the driver can be suppressed.
JP 2002-372143 A (page 5, FIG. 4)

  According to the above-described shift control device, although the opening degree threshold for determining the release of the acceleration mode is changed according to the driving state, when the driver continues to step on the accelerator pedal, the accelerator opening degree becomes smaller than the opening degree threshold. The acceleration mode is maintained without going below. However, even in a situation where the accelerator pedal is depressed, continuing the traveling in the acceleration mode does not necessarily improve the power performance. In other words, if the engine continues to be driven in a high rotation range based on the acceleration mode, the engine will eventually rotate past the torque peak, and therefore, further increase in driving torque cannot be desired, and the driver It was difficult to give a sense of acceleration. Moreover, maintaining the engine speed at a high speed has been a factor that causes an increase in vehicle noise and fuel consumption.

  An object of the present invention is to suppress vehicle noise and improve fuel efficiency performance by appropriately canceling an acceleration mode according to the traveling state of the vehicle.

  The transmission control device for a continuously variable transmission according to the present invention is a continuously variable transmission that continuously changes the rotation of an input-side rotating body driven by an engine via a power transmission element and transmits it to an output-side rotating body. Acceleration request determination means for determining a driver's acceleration request according to the accelerator pedal depression state, and acceleration from the normal shift mode when the acceleration request determination means determines that there is an acceleration request. Acceleration mode switching means for controlling the target rotational speed of the input-side rotator to a higher rotational speed than the normal speed change mode, and a hold time for maintaining the acceleration mode are set based on the running state of the vehicle. Under the hold time setting means and the state switched to the acceleration mode, the hold time has elapsed since the input side rotating body has reached the target rotational speed. Kiniwa, and having an acceleration mode canceling means for canceling the acceleration mode.

  In the transmission control device for a continuously variable transmission according to the present invention, the hold time setting means is configured to determine the hold time based on at least one of throttle opening, accelerator operation frequency, vehicle acceleration, road gradient, and traveling landform. It is characterized by setting the length.

  According to the present invention, since the release of the acceleration mode is determined using the hold time, the acceleration mode is positively activated in a driving situation in which a feeling of acceleration cannot be obtained even if the target rotation speed is maintained at a high speed. It can be canceled. For this reason, it is possible to suppress the noise of the vehicle and improve the fuel efficiency without continuing to drive the engine in a high rotation range.

  In addition, since the length of the hold time is set according to the traveling state of the vehicle, the acceleration mode can be continued for a long time when the driver's acceleration request is large, and the driver does not feel uncomfortable.

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

  FIG. 1 is a skeleton diagram showing a continuously variable transmission 10 mounted on a vehicle. As shown in FIG. 1, the continuously variable transmission 10 is a belt-type continuously variable transmission, and includes a primary shaft 12 driven by an engine 11 and a secondary shaft 13 parallel to the primary shaft 12. A transmission mechanism is provided between the primary shaft 12 and the secondary shaft 13, and the rotation of the primary shaft 12 is shifted and transmitted to the secondary shaft 13. The rotation of the secondary shaft 13 is transmitted to the left and right drive wheels 16 and 17 via the speed reduction mechanism 14 and the differential mechanism 15.

  The primary shaft 12 is provided with a primary pulley 20 which is an input side rotating body. The primary pulley 20 is fixed to the primary shaft 12 in the axial direction, and a fixed pulley 20 a integrated with the primary shaft 12. And a movable pulley 20b that is slidably mounted. Further, the secondary shaft 13 is provided with a secondary pulley 21 that is an output side rotating body. The secondary pulley 21 is fixed to the secondary shaft 13 and a fixed pulley 21a integrated with the secondary shaft 13, and the secondary shaft 21 is opposed to the secondary shaft 13. And a movable pulley 21b mounted so as to be slidable in the direction.

  A drive belt 22 that is a power transmission element is stretched between the primary pulley 20 and the secondary pulley 21, and the groove width between the primary pulley 20 and the secondary pulley 21 is changed to change the ratio of the winding diameter of the drive belt 22. Is changed, the rotation of the primary shaft 12 is steplessly changed and transmitted to the secondary shaft 13. If the winding diameter of the drive belt 22 around the primary pulley 20 is Rp and the winding diameter around the secondary pulley 21 is Rs, the transmission ratio is Rs / Rp.

  In order to change the groove width of the primary pulley 20, a plunger 23 is fixed to the primary shaft 12, and a primary cylinder 24 slidably contacting the outer peripheral surface of the plunger 23 is fixed to the movable pulley 20b. A hydraulic oil chamber 25 is defined by the primary cylinder 24 and the primary cylinder 24. On the other hand, in order to change the groove width of the secondary pulley 21, a plunger 26 is fixed to the secondary shaft 13, and a secondary cylinder 27 slidably contacting the outer peripheral surface of the plunger 26 is fixed to the movable pulley 21b. And the secondary cylinder 27 define a hydraulic oil chamber 28. The groove widths of the pulleys 20 and 21 are set by adjusting the primary pressure Pp introduced into the primary hydraulic fluid chamber 25 and the secondary pressure Ps introduced into the secondary hydraulic fluid chamber 28. .

  A torque converter 30 and a forward / reverse switching mechanism 31 are provided between the crankshaft 11 a and the primary shaft 12 in order to transmit engine power to the primary pulley 20. The torque converter 30 includes a pump shell 30a connected to the crankshaft 11a and a turbine runner 30b facing the pump shell 30a. A torque converter shaft 32 is connected to the turbine runner 30b. In addition, a lock-up clutch 33 for fastening the crankshaft 11a and the torque converter shaft 32 is incorporated in the torque converter 30 according to the traveling state.

  The forward / reverse switching mechanism 31 includes a double-pinion planetary gear train 34, a forward clutch 35, and a reverse brake 36. By operating the forward clutch 35 and the reverse brake 36, the forward / reverse switching mechanism 31 is operated. The power transmission path inside can be switched. When both the forward clutch 35 and the reverse brake 36 are released, the torque converter shaft 32 and the primary shaft 12 are disconnected, and the forward / reverse switching mechanism 31 is switched to a neutral state in which no power is transmitted to the primary shaft 12. When the forward clutch 35 is engaged with the reverse brake 36 released, the rotation of the torque converter shaft 32 is transmitted to the primary pulley 20 as it is. Further, when the reverse brake 36 is engaged with the forward clutch 35 released, the rotation of the torque converter shaft 32 is reversed and transmitted to the primary pulley 20.

  FIG. 2 is a schematic diagram showing a hydraulic control system and an electronic control system of the continuously variable transmission 10. As shown in FIG. 2, the continuously variable transmission 10 is provided with an oil pump 40 driven by the engine 11 in order to supply hydraulic oil to the primary pulley 20 and the secondary pulley 21. The secondary pressure path 42 connected to the discharge port of the oil pump 40 is connected to the hydraulic oil chamber 28 of the secondary pulley 21 and to the pressure regulating port 43 a of the secondary pressure regulating valve 43. The line pressure, that is, the secondary pressure Ps adjusted by the secondary pressure adjusting valve 43 is adjusted to a pressure that gives the drive belt 22 a tension necessary for torque transmission.

  The secondary pressure path 42 is connected to the input port 44 a of the primary pressure adjustment valve 44, and the primary pressure path 45 extending from the output port 44 b of the primary pressure adjustment valve 44 is connected to the hydraulic oil chamber 25 of the primary pulley 20. Yes. The primary pressure adjusting valve 44 adjusts the secondary pressure Ps to the primary pressure Pp according to the target gear ratio, and the groove width of the primary pulley 20 is set.

  Here, the primary pressure Pp is a pressure obtained by reducing the secondary pressure Ps. Since the pressure receiving area of the hydraulic oil chamber 25 is set larger than that of the hydraulic oil chamber 28, the primary pulley Pp is controlled by controlling the primary pressure Pp. The groove width of the secondary pulley 21 can be changed via the drive belt 22 while changing the groove width of 20. The secondary pressure regulating valve 43 and the primary pressure regulating valve 44 are electromagnetic pressure control valves, respectively. By controlling the current value supplied from the CVT control unit 41 to the solenoid coils 43b and 44c, the secondary pressure Ps and the primary pressure Pp Can be adjusted.

  The CVT control unit 41 that controls the gear ratio of the continuously variable transmission 10 by controlling the groove widths of the primary pulley 20 and the secondary pulley 21 includes a microprocessor (CPU) (not shown). The ROM, RAM, and I / O port are connected via the interface. The ROM stores a control program, an engine torque map, and the like, and the RAM temporarily stores data calculated by the CPU. Also, detection signals indicating the running state of the vehicle are input from various sensors to the CPU via the I / O port.

  As various sensors for inputting a detection signal to the CVT control unit 41, a primary rotational speed sensor 50 for detecting the rotational speed of the primary pulley 20, a secondary rotational speed sensor 51 for detecting the rotational speed of the secondary pulley 21, an accelerator opening Ao, An accelerator pedal sensor 52 that detects the accelerator opening speed VAo, a vehicle speed sensor 53 that detects the vehicle speed, a throttle opening sensor 54 that detects the opening of the throttle valve, an engine speed sensor 55 that detects the engine speed, and a vehicle width direction There are a lateral G sensor 56 for detecting the acting vehicle acceleration, a longitudinal G sensor 57 for detecting the vehicle acceleration acting in the longitudinal direction of the vehicle, and the like. An engine control unit 58 is connected to the CVT control unit 41 so that the continuously variable transmission 10 and the engine 11 are controlled in cooperation with each other. A turbine rotational speed sensor that detects the rotational speed of the torque converter shaft 32 may be provided, and the rotational speed of the primary pulley 20 may be detected based on a detection signal from the turbine rotational speed sensor.

  Hereinafter, the shift control of the continuously variable transmission 10 by the CVT control unit 41 will be described. FIG. 3 is a block diagram showing a shift control system of the CVT control unit 41. As shown in FIG. 3, the CVT control unit 41 includes a target primary rotation speed calculation unit 60, a target gear ratio calculation unit 61, a hydraulic pressure ratio calculation unit 62, and a target primary pressure calculation unit 63 in order to calculate the target primary pressure Pp. I have. The target primary rotational speed calculation unit 60 calculates the target primary rotational speed Np by referring to the speed change characteristic map based on the vehicle speed V and the throttle opening degree To, and the target speed ratio calculation unit 61 calculates the target primary rotational speed Np and A target gear ratio is calculated based on the actual secondary rotational speed Ns ′. Next, the hydraulic ratio calculation unit 62 calculates the hydraulic ratio (Pp / Ps) between the target primary pressure Pp and the target secondary pressure Ps corresponding to the target speed ratio i, and the target primary pressure calculation unit 63 calculates the hydraulic ratio. The target primary pressure Pp is calculated by multiplying the target secondary pressure Ps.

  Further, the CVT control unit 41 includes an actual gear ratio calculation unit 64, a feedback value calculation unit 65, and an addition unit 66 in order to perform feedback control of the target primary pressure Pp. The actual gear ratio calculation unit 64 calculates the actual gear ratio i ′ based on the actual primary rotation speed Np ′ and the actual secondary rotation speed Ns ′, and the feedback value calculation unit 65 calculates the actual gear ratio i ′ and the target gear ratio. A feedback value is calculated based on i. Next, the adding unit 66 adds the feedback value to the target primary pressure Pp, and the target primary pressure Pp is feedback-controlled. Then, based on the feedback-controlled target primary pressure Pp, the primary pressure adjustment valve 44 is controlled, and the groove width of the primary pulley 20 is adjusted.

  Further, the CVT control unit 41 includes an input torque calculation unit 67, a required secondary pressure calculation unit 68, and a target secondary pressure calculation unit 69 in order to calculate the target secondary pressure Ps. The input torque calculation unit 67 calculates the input torque Ti input from the engine 11 to the primary shaft 12 based on the engine speed and the throttle opening degree To, and the required secondary pressure calculation unit 68 sets the target speed ratio i. Based on this, the required secondary pressure is calculated. The input torque Ti and the required secondary pressure are input to the target secondary pressure calculation unit 69, and the target secondary pressure calculation unit 69 calculates the target secondary pressure Ps. Based on the target secondary pressure Ps, the primary pressure adjustment valve 44 is controlled, and the secondary pulley 21 generates a tightening force commensurate with the transmission torque capacity of the drive belt 22.

  The CVT control unit 41 executes a shift control while appropriately switching between a normal shift mode applied during normal travel and an acceleration mode applied according to the driver's acceleration request according to the travel state of the vehicle. The CVT control unit 41 stores a shift characteristic map, a control program, and the like corresponding to these two shift modes. Next, a shift characteristic map applied in the normal shift mode, that is, a normal shift map, and a shift characteristic map applied in the acceleration mode, that is, an acceleration map will be described.

  FIGS. 4A and 4B are shift characteristic maps for calculating the target primary rotational speed Np based on the vehicle speed V and the throttle opening degree To, and FIG. 4A is a normal characteristic applied in the normal shift mode. A shift map is shown, and (B) shows an acceleration map applied in the acceleration mode.

  As shown in FIG. 4 (A), the normal speed change map increases or decreases between the characteristic line Low at which the speed ratio is maximum and the characteristic line OD at which the speed ratio is minimum as the accelerator pedal is depressed. A plurality of characteristic lines TV1 to TV4 corresponding to the throttle opening degree To are set. When the throttle opening To is low, the target primary rotational speed Np is calculated along the characteristic line TV1, and as the throttle opening To increases, the target primary rotational speed Np is calculated along the characteristic line TV2 and the characteristic line TV3. The When the throttle opening degree To is fully opened, the target primary rotational speed Np is calculated along the characteristic line TV4.

  For example, when the accelerator pedal is fully opened to accelerate the vehicle from a stopped state, the target primary rotational speed Np reaches point A along the characteristic line Low, and the speed ratio is changed to the overdrive side and the target The point B is reached with a slight increase in the primary rotational speed Np. When the accelerator pedal is released from this state, the target primary speed Np reaches point C along the characteristic line OD, changes the gear ratio to the low side, and decreases the target primary speed Np slightly while reducing the point D. To reach. Then, the vehicle stops in a state where the gear ratio is maintained on the low side. In actual traveling, since the throttle opening To changes according to the driver's operation, the speed is changed based on the target primary rotational speed Np within the range of the thick line indicated by points A to D in FIG. Control is executed.

  Further, as shown in FIG. 4B, the acceleration map includes a characteristic line TV1 between the characteristic line Low and the characteristic line OD on the higher rotation side than the characteristic lines TV1 to TV4 in FIG. “˜TV4” is set, and these characteristic lines TV1 ′ to TV4 ′ indicate the characteristics at the same throttle opening degree To as the characteristic lines TV1 to TV4, respectively. In other words, under the state of switching to the acceleration mode, when the driver depresses the accelerator pedal up to the characteristic line TV3, the target primary rotational speed Np is set based on the characteristic line TV3 ′ on the higher rotation side than the characteristic line TV3. Therefore, in the acceleration mode, the target primary rotation speed Np is set on the higher rotation side than in the normal transmission mode. When the vehicle actually travels in a state where the acceleration mode is set, as described above, the target primary rotational speed within the range of the thick line indicated by points A ′ to D in FIG. 4B. Shift control with improved vehicle acceleration performance is executed based on Np.

  Next, switching between the normal shift map and the acceleration map referred to when calculating the target primary rotation speed Np, that is, switching control between the normal shift mode and the acceleration mode will be described. FIG. 5 is a block diagram showing a shift mode switching control system of the CVT control unit 41. As shown in FIG.

  As shown in FIG. 5, the CVT control unit 41 includes an acceleration request determination unit 70 that is an acceleration request determination unit, and a shift mode switching unit 71 that is an acceleration mode switching unit and an acceleration mode release unit. The acceleration request determination unit 70 determines whether or not there is an acceleration request by the driver based on the accelerator opening Ao and the accelerator opening speed VAo input from the accelerator pedal sensor 52. The acceleration request determination unit 70 operates when the accelerator opening speed VAo, which is the accelerator pedal depression speed, exceeds a predetermined value, and the accelerator opening Ao, which is the accelerator pedal depression amount, exceeds a predetermined value. It is determined that there is an acceleration request from the user, and this determination signal is output to the shift mode switching unit 71. Further, when the accelerator opening speed VAo and the accelerator opening Ao do not satisfy the conditions, it is determined that there is no acceleration request from the driver, and this determination signal is output to the shift mode switching unit 71.

  If it is determined that there is an acceleration request, the shift mode switching unit 71 selects an acceleration map in which the target primary rotational speed Np is set to the high rotational side, and the acceleration map is used when calculating the target primary rotational speed Np. Will be referenced. On the other hand, when it is determined that there is no acceleration request, the shift mode switching unit 71 selects the normal shift map in which the target primary rotation speed Np is set to the low rotation side, and calculates the target primary rotation speed Np. The normal shift map is referred to.

  The CVT control unit 41 includes an operation frequency calculation unit 72 and a hold time calculation unit 73 that is a hold time setting unit. The operation frequency calculation means calculates the accelerator operation frequency Af based on the accelerator opening Ao input from the accelerator pedal sensor 52, and outputs the accelerator operation frequency Af to the hold time calculation unit 73. Furthermore, the throttle opening degree To is input from the throttle opening degree sensor 54 to the hold time calculation unit 73, and the hold time calculation unit 73 sets the hold time Th based on the accelerator operation frequency Af and the throttle opening degree To. calculate. The calculated hold time Th is input from the hold time calculation unit 73 to the transmission mode switching unit 71 and used as a determination condition when releasing the acceleration mode. Note that the calculation procedure of the accelerator operation frequency Af in the operation frequency calculation unit 72 and the calculation procedure of the hold time Th in the hold time calculation unit 73 will be described later.

  FIG. 6 is a speed change characteristic map showing a changing process of the target primary rotational speed Np in the acceleration mode. In the speed change characteristic map of FIG. 6, the normal speed change map and the acceleration map are shown in an overlapping manner. Hereinafter, the shift control when the accelerator pedal is depressed to the characteristic line TV3 ′ and the shift mode is switched from the normal shift mode to the acceleration mode will be described.

  As shown in FIG. 6, when the accelerator pedal is depressed quickly while traveling at the state point P1 in a state where the normal shift mode is set, the shift mode is changed from the normal shift mode to the acceleration mode. Can be switched to. In this acceleration mode, the first acceleration control for rapidly controlling the gear ratio to the low side, the second acceleration control for increasing the engine speed while maintaining the gear ratio, and the characteristic lines TV1 ′ to TV4 ′ of the acceleration map Along with this, the third acceleration control is performed in which the engine speed is increased while changing the gear ratio to the overdrive side. That is, the first acceleration control and the second acceleration control are transient controls for shifting from the normal shift map to the acceleration map.

  When the shift mode is switched to the acceleration mode by depressing the accelerator pedal, the target primary rotational speed calculation unit 60 sets the target primary rotational speed Np3 corresponding to the state point P3 on the characteristic line TV3 ′, that is, the target rotational speed in the acceleration mode. Is calculated. This target primary rotation speed Np3 is calculated from the state point P3 that is the intersection of the speed ratio applied in the second acceleration control and the characteristic line TV3 ′.

In this way, the CVT control unit 41 first executes the first acceleration control in order to reach the actual primary rotational speed Np ′ to the calculated target primary rotational speed Np3.
In the first acceleration control, the gear ratio is rapidly controlled to the low side while increasing the engine speed from the state point P1 toward the state point P2. As a result, the continuously variable transmission 10 is downshifted to prepare for acceleration of the vehicle. Subsequently, in the second acceleration control, in order to make the actual primary rotational speed Np ′ reach the target primary rotational speed Np3 corresponding to the state point P3, the engine rotational speed increase control is performed under a state where the gear ratio is fixed. Is executed.

  Subsequently, when it is determined that the actual primary rotational speed Np ′ has reached the target primary rotational speed Np3, the hold time Th is set and the third acceleration control along the characteristic line TV3 ′ is started. . A predetermined hysteresis width is set for the target primary rotational speed Np3, and it is determined that the target primary rotational speed Np3 has been reached when the actual primary rotational speed Np ′ converges within this hysteresis width. It is like that.

  When the third acceleration control is started, the CVT control unit 41 starts the count control of the hold time Th, and the third acceleration control is released when the hold time Th elapses from the start. That is, even if the driver maintains the amount of depression of the accelerator pedal, the acceleration mode is canceled as the hold time Th elapses, and the CVT control unit 41 changes the target primary rotational speed Np from the state point P4 to the state. After that, the shift control is executed based on the normal shift mode.

  Next, a procedure for setting the hold time Th that is a condition for canceling the acceleration mode will be described. FIG. 7 shows map data referred to when the hold time Th is set. As shown in FIG. 7, a hold time Th having various time lengths is set as map data according to the accelerator operation frequency Af and the throttle opening degree To, and this map data is the hold time of the CVT control unit 41. It is stored in the calculation unit 73. Here, the accelerator operation frequency Af is data obtained by moving and averaging the absolute value of the accelerator opening speed VAo at a predetermined sampling period, and is a numerical value of the operation state of the accelerator pedal by the driver. The accelerator operation frequency Af is calculated to be large when the accelerator pedal is frequently operated, and is calculated to be small when the operation of the accelerator pedal is kept constant.

  As shown in the map data of FIG. 7, the hold time Th is set based on the accelerator operation frequency Af, and the hold time Th is set longer as the accelerator operation frequency Af increases. The hold time Th is set separately for a case where the throttle opening degree To is fully open (To = fully open) and an opening process (To <fully open). When the throttle opening degree To is fully open, the opening time Th is set. The hold time Th is set longer than that in the process. That is, when the throttle opening To is in the opening process, the hold time Ta is selected if the accelerator operation frequency Af is calculated to be small, while the hold time longer than the hold time Ta is calculated if the accelerator operation frequency Af is calculated to be large. Time Tb is selected. Even if the same accelerator operation frequency Af is calculated, if the throttle opening To is fully open, hold times Tc and Td longer than the hold times Ta and Tb are selected. become.

  Thus, the hold time Th is set shorter as the accelerator operation frequency Af and the throttle opening To are smaller, that is, the acceleration request by the driver is weaker, and as the accelerator operation frequency Af and the throttle opening To are larger, that is, the operation. The hold time Th is set longer as the acceleration request by the person is stronger. The map data shown in the figure is set separately for the case where the throttle opening degree To is fully open and the case where the throttle opening degree To is in the opening process. However, the present invention is not limited to this, and from fully closed to fully open. The hold time Th may be set for each throttle opening range by further dividing the throttle opening To. Further, the condition for selecting the hold time Th is not limited to the accelerator operation frequency Af and the throttle opening degree To, but is calculated from the vehicle acceleration and the running resistance to which the vertical G sensor and the lateral G sensor are input. Information such as the road surface gradient and the traveling terrain input from the navigation system may be used.

  FIG. 8 is a flowchart showing a switching procedure between the normal transmission mode and the acceleration mode. In addition, the flowchart of FIG. 8 is connected in the position of the code | symbol a. Hereinafter, the shift mode switching control described above will be described with reference to a flowchart.

  As shown in FIG. 8, the normal shift mode is set in step S1, and the normal shift control is executed in step S2. Thus, under the state where the normal shift control is executed, in step S3, the driver's acceleration request is determined based on the accelerator opening Ao and the accelerator opening speed VAo. If it is determined in step S3 that there is an acceleration request, the process proceeds to step S4, and the shift mode is switched to the acceleration mode. On the other hand, if it is determined that there is no acceleration request, the normal shift control is continued. It will be.

  When the mode is switched to the acceleration mode in step S4, the first and second acceleration controls, which are the transient controls described above, are executed in step S5, and whether or not the actual primary rotation speed Np ′ has reached the target primary rotation speed Np in step S6. Is determined. If it is determined in step S6 that the target primary speed Np has been reached, the process proceeds to step S7, where the hold time Th is set based on the throttle opening To and the accelerator operation frequency Af, while the target primary speed is set. When it is determined that Np has not been reached, the first and second acceleration control is executed until the target primary rotational speed Np is reached.

  When the hold time Th is set in step S7, the third acceleration control along the characteristic line TV3 ′ is started in the subsequent step S8, and the hold time Th has elapsed since the third acceleration control was started in the subsequent step S9. It is determined whether or not. If it is determined in step S9 that the hold time Th has elapsed, the process proceeds to step S10, and the acceleration mode is canceled to exit the routine. On the other hand, if it is determined that the hold time Th has not elapsed, the hold time Th is The third acceleration control is executed until the time Th elapses.

  In the flowchart shown in FIG. 8, the acceleration mode is canceled only when the hold time Th elapses. However, during the execution of the first to third acceleration controls in the acceleration mode, the driver depresses the accelerator pedal. When it is largely returned or a failure signal is output from the accelerator pedal sensor 52 or the throttle opening sensor 54, the acceleration mode is canceled even if the hold time Th has not elapsed.

  Next, an effect obtained by releasing the acceleration mode with the lapse of the hold time Th will be described. FIG. 9 is a diagram showing the accelerator opening Ao and the target primary rotational speed Np. In this diagram, the acceleration mode is switched by the driver's accelerator operation, and the acceleration mode is canceled when the hold time Th elapses. The process up to this point is shown.

  As shown in FIG. 9, the third acceleration control in the acceleration mode started when the actual primary rotational speed Np ′ reaches the state point P3 described above is performed when the hold time Th elapses from the start. Even if the pedal depression amount is maintained, it is released. Therefore, after the hold time Th elapses, as shown by a broken line in FIG. 9, the high target primary rotational speed Np based on the acceleration map is not continuously maintained, and the target primary rotational speed suppressed based on the normal shift map is maintained. Np is calculated.

  That is, since the release of the acceleration mode is determined using the hold time Th without determining the cancellation of the acceleration mode only by the driver's accelerator operation, even if the target primary rotational speed Np is maintained at a high speed. The acceleration mode can be positively canceled in a driving situation in which a feeling of acceleration cannot be obtained. For this reason, it is possible to suppress the noise of the vehicle and improve the fuel efficiency without continuing to drive the engine in a high rotation range. Moreover, since the length of the hold time Th is set based on the magnitude of the driver's acceleration request, the acceleration mode can be continued for a long time when the acceleration request is large, giving the driver a sense of incongruity. There is nothing.

  Further, as described above, when the length of the hold time Th is set based on the vehicle acceleration, the magnitude of the acceleration feeling given to the driver can be appropriately determined, and the hold time for continuing the acceleration mode. Th can be set more accurately. Thereby, the power performance of the vehicle can be enhanced while considering the vehicle noise and fuel efficiency. In addition, when setting the length of the hold time Th based on the road surface gradient or the traveling landform, for example, the hold time Th applied on a mountain road with a height difference or a mountain road with continuous corners is set appropriately. Can do. In such a running state, by setting the hold time Th to be long and maintaining the acceleration mode, the engine speed can be kept high, the acceleration performance can be improved and the engine brake operation can be ensured. It is possible to run the vehicle.

  FIG. 10 is a shift characteristic map showing the changing process of the target primary rotation speed Np, and shows the changing process when the accelerator operation is performed during the execution of the third acceleration control. In addition, about the same state point as the state point shown in FIG. 6, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 10, when the accelerator pedal is fully opened by the driver at the state point P3 ′ in which the third acceleration control is being executed, a new target corresponding to the depressed throttle opening To is obtained. A primary rotational speed (target rotational speed) Np4 is calculated. Subsequently, the second acceleration control is executed by the CVT control unit 41 in order to reach the actual primary rotational speed Np ′ to the calculated target primary rotational speed Np4. When it is determined at the state point P3a that the actual primary rotational speed Np ′ has reached the target primary rotational speed Np3, a new hold time Tha is set, and along the characteristic line TV4 ′ at this hold time Tha Third acceleration control is executed. Then, after the hold time Tha elapses, the acceleration mode is switched to the normal shift mode, and the target primary rotational speed Np decreases from the state point P4a to the state point P5a with the normal shift map as a target.

  In addition, when the accelerator pedal is gradually loosened in the range where the acceleration mode is not released by the driver at the state point P3 ′, a new target primary rotational speed (target rotational speed) corresponding to the relaxed throttle opening To. ) Np1 is calculated. Subsequently, in order to make the actual primary rotational speed Np ′ reach the calculated target primary rotational speed Np1, the rotational speed lowering control is executed by the CVT control unit 41. When it is determined at the state point P3b that the actual primary rotational speed Np ′ has reached the target primary rotational speed Np1, a new hold time Thb is set, and the characteristic line TV1 ′ is met at the hold time Thb. Third acceleration control is executed. After the hold time Thb elapses, the acceleration mode is switched to the normal shift mode, and the target primary rotation speed Np decreases from the state point P4b to the state point P5b with the normal shift map as a target.

  As described above, when the accelerator operation is performed during the third acceleration control, the target primary rotation speed Np as the target rotation speed changes every time, and therefore the third acceleration control is once canceled together with the hold time Th. The new hold times Tha and Thb are set according to the vehicle state, and the third acceleration control corresponding to the new target primary rotation speed Np is executed within the hold times Tha and Thb. Thereby, even if the accelerator operation is executed during the third acceleration control, it is possible to execute the appropriate acceleration control without causing the driver to feel uncomfortable.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, the throttle opening To may be calculated based on the accelerator opening Ao from the accelerator pedal sensor 52, and the accelerator operation frequency Af may be calculated based on the throttle opening To from the throttle opening sensor 54. Anyway.

  The CVT control unit 41 controls the transmission ratio of the continuously variable transmission 10 while appropriately selecting two transmission modes according to the running state. However, the transmission mode is limited to the normal transmission mode and the acceleration mode. In this case, more shift modes may be set.

  Furthermore, characteristic lines TV1 to TV4 and TV1 ′ to TV4 ′ for calculating the target primary rotational speed Np are set in the normal shift map and the acceleration map shown in the figure. A characteristic line may be set.

  Further, in the above description, the target primary rotational speeds Np1, Np3, and Np4 are described as target rotational speeds. However, the target rotational speed is not limited to these, and the target rotational speed may be the vehicle speed V or the throttle opening degree. It is appropriately set according to To.

  Note that the continuously variable transmission to which the shift control device of the present invention is applied is not limited to the belt-type continuously variable transmission 10 shown in the figure, and may be a toroidal continuously variable transmission. Absent.

It is a skeleton figure which shows the continuously variable transmission mounted in a vehicle. It is the schematic which shows the hydraulic control system and electronic control system of a continuously variable transmission. It is a block diagram which shows the transmission control system of a CVT control unit. (A) and (B) are shift characteristic maps for calculating the target primary rotational speed based on the vehicle speed and the throttle opening. It is a block diagram which shows the transmission mode switching control system of a CVT control unit. 6 is a speed change characteristic map showing a changing process of a target primary rotational speed in an acceleration mode. This is map data referred to when setting the hold time. It is a flowchart which shows the switching procedure of normal transmission mode and acceleration mode. It is a diagram which shows an accelerator opening and a target primary rotation speed. 6 is a speed change characteristic map showing a changing process of a target primary rotational speed in an acceleration mode.

Explanation of symbols

10 continuously variable transmission 11 engine 20 primary pulley (input side rotating body)
21 Secondary pulley (output side rotating body)
22 Drive belt (power transmission element)
70 Acceleration request determination unit (acceleration request determination means)
71 Shift mode switching unit (acceleration mode switching means, acceleration mode release means)
73 Hold time calculation section (hold time setting means)
Np1, Np3, Np4 Target primary speed (target speed)
Th, Tha, Thb Hold time To Throttle opening Af Accelerator operation frequency

Claims (2)

A transmission control device for a continuously variable transmission that continuously changes the rotation of an input-side rotator driven by an engine via a power transmission element and transmits it to an output-side rotator,
Acceleration request determination means for determining the driver's acceleration request according to the accelerator pedal depression state;
When the acceleration request determination means determines that there is an acceleration request, the mode is switched from the normal shift mode to the acceleration mode, and the acceleration mode switch for controlling the target rotational speed of the input side rotating body to the higher rotation side than the normal shift mode Means,
A hold time setting means for setting a hold time for maintaining the acceleration mode based on a running state of the vehicle;
Acceleration mode canceling means for canceling the acceleration mode when the hold time elapses after the input side rotating body reaches the target rotation speed under the state of switching to the acceleration mode. A transmission control device for a continuously variable transmission. 2. The shift control device for a continuously variable transmission according to claim 1, wherein the hold time setting means is based on at least one of throttle opening, accelerator operation frequency, vehicle acceleration, road gradient, and traveling terrain. A transmission control device for a continuously variable transmission, characterized in that the length of time is set.

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