JP5186938B2 - Control device for continuously variable transmission - Google Patents

Description

  The present invention relates to a control device for a continuously variable transmission, and more particularly to a technique for controlling the gear ratio of a continuously variable transmission so as not to perform unnecessary downshifts.

  2. Description of the Related Art Conventionally, continuously variable transmissions that change a gear ratio steplessly are known. In the continuously variable transmission, it is possible to control the engine speed so that the fuel efficiency is optimized. For example, during acceleration, the engine speed (input shaft speed of the continuously variable transmission) is shifted down to a speed that provides a good balance between torque and fuel consumption, and then the engine speed is kept constant. Upshifts can be made to accelerate the vehicle.

  However, such an acceleration method is different from an acceleration method in a vehicle equipped with an automatic transmission or the like in which the gear ratio changes stepwise. The feeling of acceleration given to the driver by the acceleration method peculiar to the continuously variable transmission is called a rubber band feel, and gives an unnatural feeling to the driver who seeks an acceleration feeling that the vehicle speed increases with the engine speed. Therefore, in order to improve drivability, it is desirable to control the gear ratio so that the vehicle speed increases with the engine speed during acceleration even in a continuously variable transmission.

  Japanese Patent Laying-Open No. 2005-61428 (Patent Document 1) discloses a control device for a continuously variable transmission that performs speed ratio (gear ratio) control that eliminates a sense of incongruity that is felt by the driver after the acceleration has been completed and the acceleration has been emphasized. Is disclosed. A control device described in Patent Document 1 is a control device for a continuously variable transmission that switches a transmission ratio of a continuously variable transmission that is drivingly coupled to an engine that is an internal combustion engine. Based on this, the engine speed, which is the operating point with the best fuel consumption rate, is calculated, the engine speed is set as the target input speed of the continuously variable transmission, and acceleration driving is achieved based on the driver's accelerator operation amount and vehicle driving environment. Estimate the converging vehicle speed that is stable at a constant speed after that, calculate the target output speed of the continuously variable transmission necessary to achieve the converging vehicle speed, and input the rotational speed and output of the continuously variable transmission during acceleration transient The speed ratio of the continuously variable transmission is switched so as to make a substantially linear transition from a combination of rotation speeds to a combination of target input rotation speed and target output rotation speed.

According to the control device described in this publication, in relation to the input rotational speed of the continuously variable transmission, the vehicle speed is substantially linearly reduced from the vehicle speed before the accelerator increasing operation to the vehicle speed at the constant speed after the accelerator increasing operation. To rise. Therefore, as shown in FIG. 16 of Japanese Patent Application Laid-Open No. 2005-61428, the input shaft rotational speed of the continuously variable transmission is delayed as compared with the shift control in which the input shaft rotational speed is determined with priority on fuel efficiency, and increases with the vehicle speed. To do. As a result, the uncomfortable feeling associated with the switching control can be eliminated.
JP 2005-61428 A

  As in the control device described in Japanese Patent Application Laid-Open No. 2005-61428, during the acceleration, if the shift control different from the shift control that determines the input shaft rotational speed is executed with priority on fuel efficiency, the input of the continuously variable transmission is performed during the acceleration. The shaft rotation speed is controlled to be relatively low. Therefore, for example, when the accelerator opening is reduced during acceleration, when returning to the shift control that determines the input shaft rotation speed by giving priority to the fuel consumption from the shift control at the time of acceleration, the input shaft rotation speed is optimized until the fuel consumption is optimized. In order to raise the engine, a downshift can be performed in spite of a decrease in the accelerator opening. Therefore, an unnatural feeling can be given to a driver who seeks an upshift as the accelerator opening decreases. However, Japanese Patent Laid-Open No. 2005-61428 does not disclose or suggest such a problem.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a control device for a continuously variable transmission that can reduce a sense of discomfort given to a driver.

  A control device for a continuously variable transmission according to a first invention is a control device for a continuously variable transmission mounted on a vehicle. The control device includes a first setting means for setting the first target input shaft speed of the continuously variable transmission in the first mode, and a continuously variable transmission in a second mode different from the first mode. A second setting means for setting the second target input shaft rotational speed of the machine, and a smaller one of the first target input shaft rotational speed and the second target input shaft rotational speed as the third target input Third setting means for setting as the shaft rotational speed, and means for controlling the gear ratio of the continuously variable transmission so that the input shaft rotational speed of the continuously variable transmission becomes the third target input shaft rotational speed With.

  According to this configuration, the smaller one of the first target input shaft rotational speed set in the first mode and the second target input shaft rotational speed set in the second mode is the third target input shaft. Set as number of revolutions. The gear ratio of the continuously variable transmission is controlled so that the input shaft rotational speed of the continuously variable transmission becomes the third target input shaft rotational speed. Thereby, for example, when switching from the shift control in the second mode to the shift control in the first mode, the gear ratio of the continuously variable transmission can be controlled so as not to downshift. Therefore, it is possible to control the continuously variable transmission so as to meet the driver's intention for an upshift. As a result, it is possible to provide a control device for a continuously variable transmission that can reduce the uncomfortable feeling given to the driver.

  The control device for a continuously variable transmission according to the second invention includes means for detecting the rate of change of the accelerator opening, and a change greater than a predetermined positive threshold in addition to the configuration of the first invention. And a means for starting to set the second target input shaft rotational speed as the third target input shaft rotational speed when the accelerator opening increases at a rate. The third setting means reduces the accelerator opening at a rate of change equal to or less than a predetermined negative threshold value in a state where the second target input shaft speed is set as the third target input shaft speed. In this case, a means for starting to set the smaller one of the first target input shaft speed and the second target input shaft speed as the third target input shaft speed is included.

  According to this configuration, when the accelerator opening increases at a rate of change equal to or greater than a predetermined positive threshold value, the second target input shaft speed set in the second mode is set to the third target input shaft. Setting as the rotation speed is started. Thereby, at the time of acceleration of a vehicle, it can control so that the input shaft rotational speed of a continuously variable transmission may become the 2nd target input shaft rotational speed set in the 2nd mode. In a state where the second target input shaft rotational speed is set as the third target input shaft rotational speed, when the accelerator opening decreases at a rate of change equal to or less than a predetermined negative threshold, the first target Setting the smaller one of the input shaft speed and the second target input shaft speed as the third target input shaft speed is started. Thus, the gear ratio of the continuously variable transmission can be controlled so as not to downshift when switching from the shift control in the second mode to the shift control in the first mode. Therefore, the continuously variable transmission can be controlled so as to follow the driver's intention to request an upshift as the accelerator opening decreases.

  A control device for a continuously variable transmission according to a third aspect of the present invention further includes means for detecting the accelerator opening and means for detecting the vehicle speed in addition to the configuration of the first or second aspect of the invention. The first setting means includes means for setting the first target input shaft speed according to a first map having the vehicle speed and the accelerator opening as parameters. The second setting means includes means for setting the second target input shaft rotational speed according to a second map different from the first map, having the vehicle speed and the accelerator opening as parameters.

  According to this configuration, the first target input shaft rotational speed is set according to the first map having the vehicle speed and the accelerator opening as parameters. A second target input shaft speed is set according to a second map having the vehicle speed and the accelerator opening as parameters. Thereby, an appropriate target input shaft rotation speed can be set according to the driving state of the vehicle and the operation of the driver.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  A vehicle equipped with a control device according to the present embodiment will be described with reference to FIG. The output of the engine 200 of the drive device 100 mounted on the vehicle is input to the belt-type continuously variable transmission 500 via the torque converter 300 and the forward / reverse switching device 400. The output of the continuously variable transmission 500 is transmitted to the reduction gear 600 and the differential gear device 700, and is distributed to the left and right drive wheels 800. The driving device 100 is controlled by an ECU (Electronic Control Unit) 900 described later. Instead of the belt-type continuously variable transmission 500, a chain-type or toroidal-type continuously variable transmission may be used.

  The torque converter 300 includes a pump impeller 302 connected to the crankshaft of the engine 200 and a turbine impeller 306 connected to the forward / reverse switching device 400 via the turbine shaft 304. A lockup clutch 308 is provided between the pump impeller 302 and the turbine impeller 306. The lockup clutch 308 is engaged or released when the hydraulic pressure supply to the engagement side oil chamber and the release side oil chamber is switched.

  When the lockup clutch 308 is completely engaged, the pump impeller 302 and the turbine impeller 306 are integrally rotated. The pump impeller 302 is provided with a mechanical oil pump 310 that generates hydraulic pressure for controlling the transmission of the continuously variable transmission 500, generating a belt clamping pressure, and supplying lubricating oil to each part. ing.

  The forward / reverse switching device 400 is composed of a double pinion type planetary gear device. Turbine shaft 304 of torque converter 300 is connected to sun gear 402. The input shaft 502 of the continuously variable transmission 500 is connected to the carrier 404. Carrier 404 and sun gear 402 are connected via forward clutch 406. Ring gear 408 is fixed to the housing via reverse brake 410. The forward clutch 406 and the reverse brake 410 are frictionally engaged by a hydraulic cylinder. The input rotational speed of the forward clutch 406 is the same as the rotational speed of the turbine shaft 304, that is, the turbine rotational speed NT.

  When the forward clutch 406 is engaged and the reverse brake 410 is released, the forward / reverse switching device 400 enters the forward engagement state. In this state, the driving force in the forward direction is transmitted to the continuously variable transmission 500. When the reverse brake 410 is engaged and the forward clutch 406 is released, the forward / reverse switching device 400 enters the reverse engagement state. In this state, the input shaft 502 is rotated in the reverse direction with respect to the turbine shaft 304. As a result, the driving force in the reverse direction is transmitted to the continuously variable transmission 500. When both forward clutch 406 and reverse brake 410 are released, forward / reverse switching device 400 enters a neutral state in which power transmission is interrupted.

  The continuously variable transmission 500 includes a primary pulley 504 provided on the input shaft 502, a secondary pulley 508 provided on the output shaft 506, and a transmission belt 510 wound around these pulleys. Power is transmitted using frictional forces between the pulleys and the transmission belt 510.

  Each pulley is composed of a hydraulic cylinder so that the groove width is variable. By controlling the hydraulic pressure of the hydraulic cylinder of the primary pulley 504, the groove width of each pulley changes. As a result, the engagement diameter of the transmission belt 510 is changed, and the gear ratio GR (= primary pulley rotation speed NIN / secondary pulley rotation speed NOUT) is continuously changed.

  As shown in FIG. 2, the ECU 900 includes an engine speed sensor 902, a turbine speed sensor 904, a vehicle speed sensor 906, a throttle opening sensor 908, a cooling water temperature sensor 910, an oil temperature sensor 912, an accelerator opening sensor 914, a foot A brake switch 916, a position sensor 918, a primary pulley rotation speed sensor 922, and a secondary pulley rotation speed sensor 924 are connected.

  The engine speed sensor 902 detects the engine speed (engine speed) NE of the engine 200. The turbine rotation speed sensor 904 detects the rotation speed (turbine rotation speed) NT of the turbine shaft 304. The vehicle speed sensor 906 detects the vehicle speed V. The throttle opening sensor 908 detects the opening degree θ (TH) of the electronic throttle valve. Cooling water temperature sensor 910 detects cooling water temperature T (W) of engine 200. The oil temperature sensor 912 detects the oil temperature T (C) of the continuously variable transmission 500 or the like. The accelerator opening sensor 914 detects the accelerator pedal opening A (CC). The foot brake switch 916 detects whether or not the foot brake is operated. The position sensor 918 detects the position P (SH) of the shift lever 920 by determining whether the contact provided at the position corresponding to the shift position is ON or OFF. Primary pulley rotation speed sensor 922 detects input shaft rotation speed (rotation speed of primary pulley 504) NIN of continuously variable transmission 500. Secondary pulley rotation speed sensor 924 detects the output shaft rotation speed (rotation speed of secondary pulley 508) NOUT of continuously variable transmission 500. A signal representing the detection result of each sensor is transmitted to ECU 900. The turbine rotational speed NT coincides with the primary pulley rotational speed NIN during forward traveling with the forward clutch 406 engaged. The vehicle speed V becomes a value corresponding to the secondary pulley rotation speed NOUT.

  ECU 900 includes a CPU (Central Processing Unit), a memory, an input / output interface, and the like. The CPU performs signal processing according to a program stored in the memory. Thereby, output control of the engine 200, shift control of the continuously variable transmission 500, belt clamping pressure control, engagement / release control of the forward clutch 406, engagement / release control of the reverse brake 410, and the like are executed.

  Output control of the engine 200 is performed by an electronic throttle valve 1000, a fuel injection device 1100, an ignition device 1200, and the like. The hydraulic control circuit 2000 performs the shift control of the continuously variable transmission 500, the belt clamping pressure control, the engagement / release control of the forward clutch 406, and the engagement / release control of the reverse brake 410.

  A part of the hydraulic control circuit 2000 will be described with reference to FIG. The hydraulic control circuit 2000 described below is an example, and the present invention is not limited to this.

  The hydraulic pressure generated by the oil pump 310 is supplied to the primary regulator valve 2100, the modulator valve (1) 2310 and the modulator valve (3) 2330 through the line pressure oil path 2002.

The primary regulator valve 2100 is selectively supplied with control pressure from one of the SLT linear solenoid valve 2200 and the SLS linear solenoid valve 2210. In the present embodiment, both the SLT linear solenoid valve 2200 and the SLS linear solenoid valve 2210 are normally open solenoid valves (the hydraulic pressure output at the time of non-energization is maximized). Note that the SLT linear solenoid valve 2200 and the SLS linear solenoid valve 2210 may be normally closed (the hydraulic pressure output when not energized is minimized (“0”)).

  The spool of the primary regulator valve 2100 slides up and down according to the supplied control pressure. As a result, the hydraulic pressure generated by the oil pump 310 is regulated (adjusted) by the primary regulator valve 2100. The hydraulic pressure adjusted by primary regulator valve 2100 is used as line pressure PL. In the present embodiment, the higher the control pressure supplied to primary regulator valve 2100, the higher the line pressure PL. Note that the higher the control pressure supplied to the primary regulator valve 2100, the lower the line pressure PL may be.

  The SLT linear solenoid valve 2200 and the SLS linear solenoid valve 2210 are supplied with the hydraulic pressure regulated by the modulator valve (3) 2330 using the line pressure PL as a source pressure.

  SLT linear solenoid valve 2200 and SLS linear solenoid valve 2210 generate control pressure according to a current value determined by a duty signal (duty value) transmitted from ECU 900.

  Of the control pressure (output hydraulic pressure) of the SLT linear solenoid valve 2200 and the control pressure (output hydraulic pressure) of the SLS linear solenoid valve 2210, the control pressure supplied to the primary regulator valve 2100 is selected by the control valve 2400.

  When the spool of the control valve 2400 is in the state (A) in FIG. 3 (left side state), the control pressure is supplied from the SLT linear solenoid valve 2200 to the primary regulator valve 2100. That is, the line pressure PL is controlled according to the control pressure of the SLT linear solenoid valve 2200.

  When the spool of the control valve 2400 is in the state (B) in FIG. 3 (right state), the control pressure is supplied from the SLS linear solenoid valve 2210 to the primary regulator valve 2100. That is, the line pressure PL is controlled according to the control pressure of the SLS linear solenoid valve 2210.

  When the spool of the control valve 2400 is in the state of (B) in FIG. 3, the control pressure of the SLT linear solenoid valve 2200 is supplied to a manual valve 2600 described later.

  The spool of the control valve 2400 is urged in one direction by a spring. Hydraulic pressure is supplied from the shift control duty solenoid (1) 2510 and the shift control duty solenoid (2) 2520 so as to oppose the urging force of the spring.

  Shift control duty solenoid (1) 2510 and shift control duty solenoid (2) 2520 output a hydraulic pressure (control pressure) corresponding to a current value determined by a duty signal (duty value) transmitted from ECU 900.

  When hydraulic pressure is supplied to the control valve 2400 from both the shift control duty solenoid (1) 2510 and the shift control duty solenoid (2) 2520, the spool of the control valve 2400 is in the state of (B) in FIG.

  When hydraulic pressure is not supplied to the control valve 2400 from at least one of the shift control duty solenoid (1) 2510 and the shift control duty solenoid (2) 2520, the spool of the control valve 2400 is driven by the biasing force of the spring. 3 is in the state (A).

  The hydraulic pressure adjusted by the modulator valve (4) 2340 is supplied to the shift control duty solenoid (1) 2510 and the shift control duty solenoid (2) 2520. The modulator valve (4) 2340 regulates the hydraulic pressure supplied from the modulator valve (3) 2330 to a constant pressure.

  The modulator valve (1) 2310 outputs a hydraulic pressure that is regulated using the line pressure PL as a source pressure. The hydraulic pressure output from the modulator valve (1) 2310 is supplied to the hydraulic cylinder of the secondary pulley 508. The hydraulic cylinder of the secondary pulley 508 is supplied with a hydraulic pressure that does not cause the transmission belt 510 to slip.

  The modulator valve (1) 2310 is provided with a spool that can move in the axial direction and a spring that biases the spool to one side. Modulator valve (1) 2310 regulates line pressure PL introduced to modulator valve (1) 2310 using the output hydraulic pressure of SLS linear solenoid valve 2210, which is duty controlled by ECU 900, as a pilot pressure. The hydraulic pressure adjusted by the modulator valve (1) 2310 is supplied to the hydraulic cylinder of the secondary pulley 508. The belt clamping pressure is increased or decreased according to the output hydraulic pressure from the modulator valve (1) 2310.

  The SLS linear solenoid valve 2210 is controlled to have a belt clamping pressure that does not cause belt slip, according to a map using the accelerator opening A (CC) and the gear ratio GR as parameters. Specifically, the excitation current for the SLS linear solenoid valve 2210 is controlled with a duty ratio corresponding to the belt clamping pressure. When the transmission torque changes suddenly during acceleration / deceleration or the like, belt slippage may be suppressed by increasing the belt clamping pressure.

  The hydraulic pressure supplied to the hydraulic cylinder of the secondary pulley 508 is detected by the pressure sensor 2312.

  The manual valve 2600 will be described with reference to FIG. Manual valve 2600 is mechanically switched according to the operation of shift lever 920. Thereby, the forward clutch 406 and the reverse brake 410 are engaged or released.

  Shift lever 920 is operated to a “P” position for parking, an “R” position for reverse travel, an “N” position for interrupting power transmission, a “D” position and “B” position for forward travel.

  In the “P” position and the “N” position, the hydraulic pressure in the forward clutch 406 and the reverse brake 410 is drained from the manual valve 2600. Thereby, the forward clutch 406 and the reverse brake 410 are released.

  In the “R” position, hydraulic pressure is supplied from the manual valve 2600 to the reverse brake 410. Thereby, the reverse brake 410 is engaged. On the other hand, the hydraulic pressure in forward clutch 406 is drained from manual valve 2600. As a result, the forward clutch 406 is released.

  When the control valve 2400 is in the state (A) in FIG. 4 (left side state), the modulator pressure PM supplied from the modulator valve (2) (not shown) is supplied to the manual valve 2600 via the control valve 2400. . The reverse brake 410 is held in the engaged state by the modulator pressure PM.

  When the control valve 2400 is in the state (B) in FIG. 4 (right side state), the hydraulic pressure adjusted by the SLT linear solenoid valve 2200 is supplied to the manual valve 2600. By adjusting the hydraulic pressure by the SLT linear solenoid valve 2200, the reverse brake 410 is gently engaged, and a shock at the time of engagement is suppressed.

  Further, when the control valve 2400 is in the state (B) in FIG. 4 (right side state), if the duty ratio of the SLT linear solenoid valve 2200 is set to 100% and the energization amount is maximized, the SLT linear solenoid valve 2200 The hydraulic pressure is not output, and the hydraulic pressure supplied to the reverse brake 410 becomes “0”. That is, the hydraulic pressure is drained from the reverse brake 410 via the SLT linear solenoid valve 2200, and the reverse brake 410 is released.

  In the “D” position and the “B” position, hydraulic pressure is supplied from the manual valve 2600 to the forward clutch 406. As a result, the forward clutch 406 is engaged. On the other hand, the hydraulic pressure in the reverse brake 410 is drained from the manual valve 2600. Thereby, the reverse brake 410 is released.

  When the control valve 2400 is in the state (A) in FIG. 4 (left side state), the modulator pressure PM supplied from the modulator valve (2) (not shown) is supplied to the manual valve 2600 via the control valve 2400. . The forward clutch 406 is held in the engaged state by the modulator pressure PM.

  When the control valve 2400 is in the state (B) in FIG. 4 (right side state), the hydraulic pressure adjusted by the SLT linear solenoid valve 2200 is supplied to the manual valve 2600. By adjusting the hydraulic pressure by the SLT linear solenoid valve 2200, the forward clutch 406 is gently engaged, and a shock at the time of engagement is suppressed.

  The SLT linear solenoid valve 2200 normally controls the line pressure PL via the control valve 2400. The SLS linear solenoid valve 2210 normally controls the belt clamping pressure via the modulator valve (1) 2310.

  On the other hand, when the neutral control execution condition including the condition that the vehicle stops (the vehicle speed becomes “0”) with the shift lever 920 in the “D” position is satisfied, the SLT linear solenoid valve 2200 The engagement force of the forward clutch 406 is controlled so that the engagement force of 406 decreases. The SLS linear solenoid valve 2210 controls the belt clamping pressure via the modulator valve (1) 2310, and controls the line pressure PL instead of the SLT linear solenoid valve 2200.

  When a garage shift is performed in which the shift lever 920 is operated from the “N” position to the “D” position or the “R” position, the forward clutch 406 or the reverse brake 410 is gently engaged with the SLT linear solenoid valve 2200. Thus, the engagement force of the forward clutch 406 or the reverse brake 410 is controlled. The SLS linear solenoid valve 2210 controls the belt clamping pressure via the modulator valve (1) 2310, and controls the line pressure PL instead of the SLT linear solenoid valve 2200.

  When the shift lever 920 is operated to the “R” position while the vehicle is traveling forward (when the vehicle speed is equal to or higher than the return speed V (R)), the SLT linear solenoid valve 2200 releases the reverse brake 410. Be controlled.

  With reference to FIG. 5, a configuration for performing the shift control will be described. Shift control is performed by controlling the supply and discharge of hydraulic pressure to and from the hydraulic cylinder of the primary pulley 504. Supply and discharge of hydraulic fluid to and from the hydraulic cylinder of the primary pulley 504 is performed using a ratio control valve (1) 2710 and a ratio control valve (2) 2720.

  The hydraulic cylinder of the primary pulley 504 is in communication with a ratio control valve (1) 2710 to which the line pressure PL is supplied and a ratio control valve (2) 2720 connected to the drain.

  The ratio control valve (1) 2710 is a valve for executing an upshift. The ratio control valve (1) 2710 is configured to open and close the flow path between the input port to which the line pressure PL is supplied and the output port connected to the hydraulic cylinder of the primary pulley 504 with a spool.

  A spring is disposed at one end of the spool of the ratio control valve (1) 2710. A port to which the control pressure from the shift control duty solenoid (1) 2510 is supplied is formed at the end opposite to the spring across the spool. Further, a port to which a control pressure is supplied from the shift control duty solenoid (2) 2520 is formed at the end on the side where the spring is disposed.

  When the control pressure from the shift control duty solenoid (1) 2510 is increased and the control pressure is not output from the shift control duty solenoid (2) 2520, the spool of the ratio control valve (1) 2710 in FIG. (D) state (right side state).

  In this state, the hydraulic pressure supplied to the hydraulic cylinder of the primary pulley 504 increases and the groove width of the primary pulley 504 becomes narrower. As a result, the gear ratio decreases. That is, an upshift is performed. Further, by increasing the supply flow rate of hydraulic oil at that time, the speed change speed is increased.

  The ratio control valve (2) 2720 is a valve for executing a downshift. A spring is disposed at one end of the spool of the ratio control valve (2) 2720. A port to which the control pressure from the shift control duty solenoid (1) 2510 is supplied is formed at the end on the side where the spring is disposed. A port to which the control pressure from the shift control duty solenoid (2) 2520 is supplied is formed at the end opposite to the spring across the spool.

  When the control pressure from the shift control duty solenoid (2) 2520 is increased and the control pressure is not output from the shift control duty solenoid (1) 2510, the spool of the ratio control valve (2) 2720 in FIG. The state (C) (the state on the left side) is reached. At the same time, the spool of the ratio control valve (1) 2710 is in the state (C) (left side state) in FIG.

  In this state, the hydraulic oil is discharged from the hydraulic cylinder of the primary pulley 504 via the ratio control valve (1) 2710 and the ratio control valve (2) 2720. Therefore, the groove width of the primary pulley 504 is widened. As a result, the gear ratio increases. That is, downshift. Further, by increasing the discharge flow rate of the hydraulic oil at that time, the speed change speed is increased.

  When controlling the gear ratio, the hydraulic pressure (control pressure) output from the shift control duty solenoid (1) 2510 and the hydraulic pressure (control pressure) output from the shift control duty solenoid (2) 2520 are It becomes a value corresponding to the duty value transmitted to the shift control duty solenoid.

  In the present embodiment, the higher the duty value, the higher the control pressure of the shift control duty solenoid. The duty value is determined according to the difference between the actual rotational speed of the input shaft 502 of the continuously variable transmission 500 and a target input shaft rotational speed set according to a map or the like described later. The greater the difference between the actual rotational speed of the input shaft 502 and the target input shaft rotational speed, the higher the duty value is set.

  In the ratio control valve (1) 2710, the force acting on the spool by the hydraulic pressure output from the shift control duty solenoid (1) 2510 acts on the spool by the hydraulic pressure output from the shift control duty solenoid (2) 2520. If it is smaller than the sum of the force and the urging force of the spring, the spool of the ratio control valve (1) 2710 will be in the state (C) (left side state).

  In the ratio control valve (2) 2720, the force acting on the spool by the hydraulic pressure output from the shift control duty solenoid (2) 2520 acts on the spool by the hydraulic pressure output from the shift control duty solenoid (1) 2510. If it is smaller than the sum of the force and the urging force of the spring, the spool of the ratio control valve (2) 2720 will be in the state (D) (right side state).

  Therefore, if the control pressure is not output from both the shift control duty solenoid (1) 2510 and the ratio control valve (2) 2720, the spool of the ratio control valve (1) 2710 is in the (C) state (the left side state). At the same time, the spool of the ratio control valve (2) 2720 is in the state (D) (right side state).

  In this state, the hydraulic pressure adjusted by the bypass control valve 2800 connected to the ratio control valve (2) 2720 is supplied to the hydraulic cylinder of the primary pulley 504. That is, the flow rate of the hydraulic oil supplied to the hydraulic cylinder of the primary pulley 504 is controlled by the bypass control valve 2800.

  A spring is disposed at one end of the spool of the bypass control valve 2800. This spring connects the input port to which the line pressure PL is supplied and the output port for outputting the hydraulic pressure (hydraulic pressure adjusted by the bypass control valve 2800) PBY finally supplied to the hydraulic cylinder of the primary pulley 504. Energize the spool in the direction.

  A port to which the output hydraulic pressure POUT from the modulator valve (1) 2310 is supplied is formed at the end where the spring is disposed. A feedback port to which the hydraulic pressure POUT output from the bypass control valve 2800 is fed back is formed at the end opposite to the spring across the spool.

  Here, in the bypass control valve 2800, the sectional area on the feedback port side is A (1), the sectional area on the port side to which the hydraulic pressure POUT from the modulator valve (1) 2310 is supplied is A (2), and the biasing force of the spring When W is W, the bypass control valve 2800 is in an equilibrium state by the following equation.

PBY × A (1) = POUT × A (2) + W (1)
When this equation (1) is transformed, the hydraulic pressure PBY output from the bypass control valve 2800 is
PBY = {A (2) / A (1)} × POUT + W / A (1) (2)
It becomes.

  In other words, the ratio control valve (2) 2720 receives the hydraulic pressure represented by the equation (2) having the term {A (2) / A (1)} × POUT.

  Therefore, when the spool of the ratio control valve (1) 2710 is in the (C) state (left side state) and the spool of the ratio control valve (2) 2720 is in the (D) state (right side state). Can finally supply the hydraulic pressure corresponding to the hydraulic pressure POUT output to control the belt clamping pressure to the hydraulic cylinder of the primary pulley 504.

  When hydraulic oil leaks from a hydraulic control circuit or hydraulic control equipment and the hydraulic pressure of the hydraulic cylinder of the primary pulley 504 decreases, the hydraulic oil is supplied little by little from the bypass control valve 2800 to the hydraulic cylinder of the primary pulley 504. The For this reason, the shift state tends to be slightly upshifted, and is a slow upshift in which the gear ratio gradually decreases.

  Hereinafter, the function of the ECU 900 will be described with reference to FIG. Note that the functions described below may be realized by software or hardware. ECU 900 may be divided into a plurality of ECUs.

  The ECU 900 includes an accelerator opening detection unit 930, a change rate detection unit 932, a vehicle speed detection unit 934, a first setting unit 941, a second setting unit 942, a steady travel control unit 950, and a linear shift control unit 952. And an off-upshift control unit 954 and a gear ratio control unit 956.

  The accelerator opening detector 930 detects the accelerator opening A (CC) based on the signal transmitted from the accelerator opening sensor 914.

  The change rate detection unit 932 detects (calculates) the change rate of the accelerator opening A (CC). When the accelerator opening A (CC) increases, the rate of change is represented by a positive value. When the accelerator opening A (CC) decreases, the rate of change is represented by a negative value. The vehicle speed detection unit 934 detects the vehicle speed V based on the signal transmitted from the vehicle speed sensor 906.

  The first setting unit 941 sets the target input shaft rotational speed NINOPT of the continuously variable transmission 500 during steady running. In the present embodiment, steady running means, for example, a running state where the vehicle speed is constant or a slow acceleration state where the acceleration is below a threshold value. During steady running, the target input shaft speed NINOPT is set as the final target input shaft speed NINC, and the actual input shaft speed NIN is continuously set to the final target input shaft speed NINC. The gear ratio of transmission 500 is controlled. However, the target input shaft rotational speed NINOPT during steady running is always set.

  The target input rotational speed NINOPT during steady travel is a target input shaft rotational speed suitable for steady travel, and is determined with priority on fuel consumption, for example. As shown in FIG. 7, the target input shaft speed NINOPT during steady running is set according to a map having the vehicle speed V and the accelerator opening A (CC) as parameters.

  The second setting unit 942 sets a target input shaft rotational speed NINLINE during linear shift control. In the present embodiment, the linear shift control means a shift control for increasing the input shaft rotational speed NIN of the continuously variable transmission 500 in proportion to the vehicle speed V after downshifting once. In the linear shift control, for example, the accelerator opening A (CC) is greater than or equal to a predetermined positive threshold and the rate of change is greater than or equal to a predetermined positive threshold. It is executed when increases.

  During linear shift control, the target input shaft speed NINLINE is set as the final target input shaft speed NINC, and the actual input shaft speed NIN is set to the final target input shaft speed NINC. The gear ratio of the step transmission 500 is controlled. However, the target input shaft speed NINLINE during linear shift control is always set.

  The target input shaft rotational speed NINLINE during the linear shift control is set according to a map having the vehicle speed, the accelerator opening, and the change rate of the accelerator opening as parameters. More specifically, the initial value of the target input shaft speed NILINE at the time of starting the linear shift control is set according to a map having the vehicle speed, the accelerator opening, and the change rate of the accelerator opening as parameters. The initial value is set in consideration of the driving force and responsiveness after the downshift. After the initial value is set, the target input shaft speed NINLINE is set in proportion to the rising gradient of the vehicle speed V (the rising gradient of the output shaft rotation speed NOUT) ΔαNOUT, as shown in FIG.

  When the accelerator opening A (CC) decreases at a rate of change equal to or less than a predetermined negative threshold during the execution of the linear shift control, the target input shaft speed NINLINE is calculated as follows: It is set according to a map having V and accelerator opening A (CC) as parameters.

  The steady travel control unit 950 sets the target input shaft speed NINOPT during steady travel as the final target input shaft speed NINC during steady travel.

  The linear shift control unit 952 determines that the accelerator opening A (CC) is greater than or equal to a predetermined positive threshold and has a rate of change greater than or equal to a predetermined positive threshold. When increases, the target input shaft speed NINLINE at the time of linear shift control is set as the final target input shaft speed NINC. That is, linear shift control is started.

  The off-up shift control unit 954 is in a state where the target input shaft rotational speed NINLINE at the time of linear shift control is set as the final target input shaft rotational speed NINC, that is, during execution of the linear shift control, If the accelerator opening A (CC) decreases at a rate of change below the threshold value, the smaller of the target input shaft speed NINOPT during steady running and the target input shaft speed NINLINE during linear shift control, Start setting the final target input shaft speed NINC. Thereby, the off-up shift control is started. In the present embodiment, the off-upshift control means a shift control that controls the gear ratio of the continuously variable transmission 500 so that the upshift is performed when the accelerator opening is decreased.

  The gear ratio control unit 956 controls the gear ratio of the continuously variable transmission 500 so that the actual input shaft rotational speed NIN becomes the finally set target input shaft rotational speed NINC.

  A control structure of a program executed by ECU 900 will be described with reference to FIGS. 10 and 11. The program executed by the ECU 900 may be recorded on a recording medium such as a CD (Compact Disc) or a DVD (Digital Versatile Disc) and distributed to the market.

  In step (hereinafter step is abbreviated as S) 100, ECU 900 determines whether or not the linear shift execution flag is on. If the linear shift execution flag is on (YES in S100), the process proceeds to S124. If the linear shift execution flag is off (NO in S100), the process proceeds to S102.

  In S102, ECU 900 determines whether or not the off-up execution flag is on. If the off-up execution flag is on (YES in S102), the process proceeds to S130. If the off-up execution flag is off (NO in S102), the process proceeds to S110.

  In S110, ECU 900 determines whether or not accelerator opening A (CC) is greater than or equal to a positive threshold value. If accelerator opening A (CC) is equal to or greater than the positive threshold value (YES in S110), the process proceeds to S112. If not (NO in S110), the process proceeds to S132.

  In S112, ECU 900 determines whether or not the rate of change of accelerator opening A (CC) is equal to or greater than a predetermined positive threshold value. If the rate of change of accelerator opening A (CC) is equal to or greater than a predetermined positive threshold value (YES in S112), the process proceeds to S120. If not (NO in S112), the process proceeds to S132.

  In S120, ECU 900 starts to set target input shaft speed NINLINE at the time of linear shift control as final target input shaft speed NINC. That is, linear shift control is started. In S122, ECU 900 turns on the linear shift execution flag.

  In S124, ECU 900 determines whether or not the change rate of accelerator opening A (CC) is equal to or less than a predetermined negative threshold value. If the rate of change of accelerator opening A (CC) is equal to or less than a predetermined negative threshold value (YES in S124), the process proceeds to S126. If not (NO in S124), the process proceeds to S130.

  In S126, ECU 900 sets the smaller one of target input shaft speed NINOPT during steady running and target input shaft speed NINLINE during linear shift control as the final target input shaft speed NINC. Start. That is, off-up shift control is started.

  In S128, ECU 900 turns off the linear shift execution flag and turns on the off-up execution flag.

  In S130, ECU 900 determines whether or not the vehicle is in a steady running state. If the vehicle is in a steady running state (YES in S130), the process proceeds to S132. If not (NO in S130), the process proceeds to S140.

  In step S132, the ECU 900 sets the target input shaft speed NINOPT during steady running as the final target input shaft speed NINC. In S134, ECU 900 turns off the linear shift execution flag and the off-up execution flag.

  In S140, ECU 900 controls the gear ratio of continuously variable transmission 500 so that actual input shaft rotational speed NIN becomes finally set target input shaft rotational speed NINC. Thereafter, the process returns to S100.

  An operation of the control device according to the present embodiment based on the above-described structure and flowchart will be described.

  If linear shift execution flag is off (NO in S100) and off-up execution flag is off (NO in S102), is accelerator opening A (CC) greater than or equal to a positive threshold value? Is determined (S110).

  At time T1 in FIG. 12, accelerator opening A (CC) is greater than or equal to a positive threshold value (YES in S110), and a positive threshold at which the rate of change of accelerator opening A (CC) is predetermined. When the value exceeds the value (YES in S112), setting of the target input shaft speed NINLINE during linear shift control as the final target input shaft speed NINC is started (S120), and the linear shift execution flag is set. Turned on (S122). The gear ratio of the continuously variable transmission 500 is controlled so that the actual input shaft rotational speed NIN becomes the finally set target input shaft rotational speed NINC (S140).

  Thereby, as shown in FIG. 12, the input shaft rotational speed NIN of the continuously variable transmission 500 can be increased in proportion to the rising gradient ΔαNOUT of the vehicle speed V. Therefore, the engine speed NE can be increased together with the vehicle speed V when the vehicle is accelerated. As a result, the rubber band feel can be reduced.

  The rate of change of the accelerator opening A (CC) at the time T2 when the target input shaft rotational speed NINLINE during linear shift control is set as the final target input shaft rotational speed NINC, that is, during execution of the linear shift control. Is equal to or smaller than a predetermined negative threshold value (YES in S124), the smaller of target input shaft speed NINOPT during steady running and target input shaft speed NINLINE during linear shift control is finally determined. The setting of the target input shaft rotational speed NINC is started (S126). That is, off-up shift control is started. The linear shift execution flag is turned off and the off-up execution flag is turned on (S128).

  The gear ratio of the continuously variable transmission 500 is controlled so that the actual input shaft rotational speed NIN becomes the finally set target input shaft rotational speed NINC (S140).

  Thereby, the gear ratio of continuously variable transmission 500 can be controlled so as not to downshift. Therefore, the gear ratio of continuously variable transmission 500 can be controlled so as to meet the driver's intention to request an upshift as accelerator opening A (CC) decreases. As a result, it is possible to reduce a sense of discomfort that can be given to the driver when the linear shift control is stopped and the shift control is performed during steady running.

  If the vehicle is in a steady running state (YES in S130), target input shaft speed NINOPT during steady running is set as final target input shaft speed NINC (S132), linear shift execution flag and off-up execution The flag is turned off (S134). The gear ratio of the continuously variable transmission 500 is controlled so that the actual input shaft rotational speed NIN becomes the finally set target input shaft rotational speed NINC (S140). As a result, the vehicle can be driven with the optimum fuel economy.

  As described above, according to the control device according to the present embodiment, the smaller of the target input shaft speed NINOPT during steady running and the target input shaft speed NINLINE during linear shift control is the final target Set as input shaft speed NINC. Thereby, for example, when switching from linear shift control to shift control during steady running, the gear ratio of the continuously variable transmission can be controlled so as not to downshift. Therefore, the gear ratio of the continuously variable transmission can be controlled so as to meet the driver's intention to request an upshift. As a result, the uncomfortable feeling given to the driver can be reduced.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic block diagram of the vehicle carrying the control apparatus which concerns on embodiment of this invention. It is a control block diagram which shows the control apparatus which concerns on embodiment of this invention. It is a figure (the 1) which shows a hydraulic control circuit. FIG. 3 is a second diagram illustrating a hydraulic control circuit. FIG. 6 is a third diagram illustrating the hydraulic control circuit. It is a functional block diagram of ECU. It is a figure which shows the map used in order to set the target input shaft rotational speed NINOPT. It is a figure which shows target input shaft rotational speed NINLINE etc. It is a figure which shows the map used in order to set the target input shaft rotational speed NINLINE. It is FIG. (1) which shows the control structure of the program which ECU performs. It is FIG. (2) which shows the control structure of the program which ECU performs. It is a figure which shows target input shaft rotational speed NINC etc.

Explanation of symbols

  100 drive device, 200 engine, 300 torque converter, 310 oil pump, 400 forward / reverse switching device, 402 sun gear, 404 carrier, 406 forward clutch, 408 ring gear, 410 reverse brake, 500 continuously variable transmission, 502 input shaft, 504 primary Pulley, 506 Output shaft, 508 Secondary pulley, 510 Transmission belt, 600 Reduction gear, 700 Differential gear device, 800 Drive wheel, 900 ECU, 902 Engine speed sensor, 904 Turbine speed sensor, 906 Vehicle speed sensor, 908 Open throttle Degree sensor, 910 Cooling water temperature sensor, 912 Oil temperature sensor, 914 Accelerator opening sensor, 916 Foot brake switch, 918 Position sensor, 920 Shift lever, 922 Imari pulley rotation speed sensor, 924 secondary pulley rotation speed sensor, 930 accelerator opening detection section, 932 change rate detection section, 934 vehicle speed detection section, 941 first setting section, 942 second setting section, 950 steady travel control section, 952 linear Shift control unit, 954 Off-up shift control unit, 956 Gear ratio control unit, 1000 Electronic throttle valve, 1100 Fuel injection device, 1200 Ignition device, 2000 Hydraulic control circuit, 2002 Line pressure oil passage, 2100 Primary regulator valve, 2200 SLT linear Solenoid Valve, 2210 SLS Linear Solenoid Valve, 2310 Modulator Valve (1), 2330 Modulator Valve (3), 2340 Modulator Valve (4), 2312 Pressure Sensor, 2400 Controller Valve, 2510 shift control duty solenoid (1), 2520 shift control duty solenoid (2), 2600 manual valve, 2710 ratio control valve (1), 2720 ratio control valve (2), 2800 bypass control valve.

Claims (3)

A control device for a continuously variable transmission mounted on a vehicle,
First setting means for setting a first target input shaft speed of the continuously variable transmission in a first mode;
Second setting means for setting a second target input shaft speed of the continuously variable transmission in a second mode different from the first mode;
A third setting means for setting the smaller one of the first target input shaft speed and the second target input shaft speed as the third target input shaft speed;
And a means for controlling a gear ratio of the continuously variable transmission so that an input shaft rotational speed of the continuously variable transmission becomes the third target input shaft rotational speed. Means for detecting the rate of change of the accelerator opening;
In order to start setting the second target input shaft rotational speed as the third target input shaft rotational speed when the accelerator opening increases at a rate of change equal to or greater than a predetermined positive threshold value. And further comprising means,
The third setting means opens the accelerator at a rate of change equal to or less than a predetermined negative threshold value in a state where the second target input shaft speed is set as the third target input shaft speed. Means for starting to set the smaller one of the first target input shaft speed and the second target input shaft speed as the third target input shaft speed when the degree decreases. The control device for a continuously variable transmission according to claim 1. Means for detecting the accelerator opening;
Means for detecting the vehicle speed,
The first setting means includes means for setting the first target input shaft rotational speed according to a first map having vehicle speed and accelerator opening as parameters.
The second setting means includes means for setting the second target input shaft speed according to a second map different from the first map, having a vehicle speed and an accelerator opening as parameters. The control device for a continuously variable transmission according to claim 1 or 2.

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