JP4556535B2 - 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 control device for a continuously variable transmission in which a gear ratio is controlled using hydraulic oil controlled by an electromagnetic valve.

  Conventionally, a belt type continuously variable transmission (CVT) is known. In this belt type continuously variable transmission, a belt is wound around a driving pulley (input shaft pulley, primary pulley) and a driven pulley (output shaft pulley, secondary pulley) each having a V-groove pulley groove. By enlarging the width of the pulley groove of the pulley and simultaneously reducing the width of the pulley groove of the other pulley, the belt wrapping radius (effective diameter) for each pulley is continuously changed, so that there is no gear ratio. Configured to set stage. The torque transmitted in this belt type continuously variable transmission is a torque corresponding to the load acting in the direction in which the belt and the pulley come into contact with each other. Therefore, the belt is clamped by the pulley so as to apply tension to the belt. Yes.

  Further, as described above, the speed change is configured to be performed by enlarging / reducing the width of the pulley groove. Specifically, each pulley is configured by a fixed sheave and a movable sheave. Is shifted by moving it back and forth in the axial direction by a hydraulic actuator provided on the back side thereof.

  The flow rate of hydraulic fluid supplied to the hydraulic actuator is controlled by an upshift speed increasing flow control valve and a downshift speed reducing flow control valve. Further, the speed increasing flow control valve is controlled by the speed increasing solenoid valve. The deceleration flow control valve is controlled by a deceleration solenoid valve.

  At the time of upshifting, duty control is repeatedly performed on and off for the speed increasing solenoid valve, so that hydraulic fluid flows from the speed increasing flow control valve into the oil chamber of the primary sheave. As a result, the radius of rotation of the portion where the V-belt is wound around the primary sheave is increased and an upshift is performed. On the other hand, at the time of downshift, duty oil control for repeatedly turning on and off the deceleration solenoid valve causes the hydraulic oil in the primary sheave oil chamber to flow out of the deceleration flow control valve. As a result, the radius of rotation of the portion where the V-belt is wound around the primary sheave is reduced and downshifting is performed. Here, the flow rate of the hydraulic oil flowing in and out from the flow rate control valve is determined based on the duty ratio value of the electromagnetic valve. Regarding the duty ratio of the solenoid valve, the duty ratio-flow rate control output characteristic is stored in the memory of an ECU (Electronic Control Unit), and the duty ratio corresponding to the flow rate of the hydraulic oil for obtaining a desired gear ratio is obtained. -The value is determined by calculating the tee ratio.

  However, since the manufacturing variation occurs in the flow rate control valve and the electromagnetic valve, the duty ratio-flow rate control output characteristic also varies. Therefore, the duty ratio-flow rate control output characteristic stored in the memory of the ECU does not necessarily match the actual duty ratio-flow rate control output characteristic, and a characteristic difference occurs between them. Accordingly, an error occurs between the desired flow rate and the actual flow rate, and the followability of the actual speed ratio with respect to the desired speed ratio is deteriorated. In order to improve the deterioration of the followability, learning correction is performed on the stored duty ratio-flow rate control output characteristic.

  Japanese Patent Laying-Open No. 2003-227564 (Patent Document 1) discloses a control device for a continuously variable transmission that corrects a duty ratio-orifice area characteristic stored in an electronic control device. The control device described in Patent Document 1 has a flow rate control unit that controls the flow rate of hydraulic fluid flowing in and out of the speed change mechanism based on an input hydraulic control signal, and a hydraulic control signal-flow rate control output characteristic of the flow rate control unit. A hydraulic control signal calculation unit that calculates a hydraulic control signal corresponding to a flow rate control output for obtaining a desired transmission ratio based on the characteristics, and a hydraulic oil capacity in the transmission mechanism at a predetermined time during the shift operation. An oil capacity detection unit that detects a change, an oil capacity estimation unit that estimates a change in hydraulic oil capacity in the transmission mechanism at a predetermined time based on a physical model that takes hydraulic control signals into account, and a detection by the oil capacity detection unit A correction unit that corrects the hydraulic control signal-flow rate control output characteristic stored in the hydraulic control signal calculation unit based on a deviation between the value and the estimated value of the oil capacity estimation unit.

According to the control device disclosed in this publication, the hydraulic control signal-flow rate control output characteristic stored in the hydraulic control signal calculation unit based on the deviation between the detection value of the oil capacity detection unit and the estimation value of the oil capacity estimation unit. Therefore, the characteristic difference between the hydraulic control signal-flow rate control output characteristic map stored in the hydraulic control signal calculation unit and the actual hydraulic control signal-flow rate control output characteristic of the flow rate control unit is accurately learned and corrected. Can do. Therefore, an error between the desired flow rate and the actual flow rate can be suppressed, and the followability of the actual speed ratio with respect to the desired speed ratio can be improved.
JP 2003-227564 A

  In the control device described in Japanese Patent Laid-Open No. 2003-227564, a change in hydraulic fluid capacity is estimated based on a physical model. However, if the physical model itself includes an error, the estimated value includes the error. In this case, the stored hydraulic control signal-flow rate control output characteristic map is erroneously corrected for learning. If the hydraulic control signal-flow rate control output characteristic map is erroneously learned so that the operation amount of the hydraulic actuator becomes excessively large, the followability becomes excessively good. In the continuously variable transmission, the gear ratio is controlled such that the actual input rotational speed NIN of the primary pulley matches the target input rotational speed NINT determined based on the accelerator opening or the like. Therefore, if the followability is excessively improved, shift hunting in which the actual input rotational speed NIN repeats overshoot and undershoot with respect to the target input rotational speed NINT occurs. As a result, there is a problem that drivability deteriorates.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a continuously variable transmission control device capable of suppressing deterioration of drivability.

  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 transmission ratio of the continuously variable transmission is controlled by hydraulic oil. The flow rate of the hydraulic oil is controlled by a solenoid valve. The control device detects a control means for controlling the electromagnetic valve and the number of times of hunting of the control signal by transmitting a control signal to the electromagnetic valve based on predetermined information regarding the flow rate of the hydraulic oil. Detection means, and a correction means for correcting predetermined information based on the number of times of hunting of the control signal in a predetermined period.

  According to the first invention, when the number of huntings of the control signal transmitted from the control means to the electromagnetic valve is detected, the flow of the hydraulic oil in advance is determined based on the number of huntings of the control signal in a predetermined period. The determined information is corrected. For example, if the number of hunting times of the control signal in a predetermined period is greater than the predetermined number, the predetermined information is corrected so as to suppress the responsiveness when controlling the gear ratio. Thus, in a continuously variable transmission in which the gear ratio is controlled so that the actual input rotation speed NIN of the primary pulley matches the target input rotation speed NINT, an overshoot of the actual input rotation speed NIN with respect to the target input rotation speed NINT and Undershoot can be suppressed. Therefore, deterioration of drivability can be suppressed. As a result, it is possible to provide a control device for a continuously variable transmission that can suppress deterioration in drivability.

  In the control device for a continuously variable transmission according to the second invention, in addition to the configuration of the first invention, the correction means has the number of hunting times of the control signal in a predetermined period larger than the predetermined number of times. In some cases, it includes means for correcting the predetermined information.

  According to the second invention, when the number of hunting times of the control signal in a predetermined period is greater than the predetermined number, the predetermined information is corrected. The predetermined information is corrected so as to suppress, for example, responsiveness when controlling the gear ratio. Thus, in a continuously variable transmission in which the gear ratio is controlled so that the actual input rotation speed NIN of the primary pulley matches the target input rotation speed NINT, an overshoot of the actual input rotation speed NIN with respect to the target input rotation speed NINT and Undershoot can be suppressed. Therefore, deterioration of drivability can be suppressed.

  In the continuously variable transmission control device according to the third aspect of the invention, in addition to the configuration of the first or second aspect of the invention, the correcting means is predetermined so as to suppress the responsiveness when controlling the speed ratio. Means for correcting the information.

  According to the third invention, the predetermined information is corrected so as to suppress the responsiveness when the speed ratio is controlled. Thus, in a continuously variable transmission in which the gear ratio is controlled so that the actual input rotation speed NIN of the primary pulley matches the target input rotation speed NINT, an overshoot of the actual input rotation speed NIN with respect to the target input rotation speed NINT and Undershoot can be suppressed. Therefore, deterioration of drivability can be suppressed.

  In the control device for a continuously variable transmission according to the fourth invention, in addition to the configuration of any one of the first to third inventions, the correcting means corrects predetermined information according to the traveling state of the vehicle. Means for.

  According to the fourth aspect of the invention, for example, the predetermined information is corrected by distinguishing the traveling state of the vehicle depending on whether the vehicle is in the steady state or the coast state. In a continuously variable transmission in which the actual input rotational speed NIN of the primary pulley is controlled so that fuel consumption is suppressed, when the running state is a steady state, the frequency of upshifting is higher than the frequency of downshifting. In such a steady state, it is possible to suppress hunting on the upshift side by correcting predetermined information regarding the flow rate of the hydraulic oil. On the other hand, in a continuously variable transmission that is controlled so that the gear ratio is increased when the vehicle speed is low, the vehicle speed decreases in the coasting state, and therefore the frequency of downshifting is higher than the frequency of upshifting. In such a coast state, hunting on the downshift side can be suppressed by correcting predetermined information.

  In the control device for a continuously variable transmission according to the fifth invention, in addition to the configuration of any one of the first to fourth inventions, the detecting means has an output cycle of the control signal within a predetermined cycle range. A means for detecting that hunting has occurred.

  According to the fifth aspect, when the control signal is output within a predetermined period, it is detected that hunting has occurred. Thereby, when the hunting of the period which influences drivability is detected, the predetermined information regarding the flow volume of hydraulic fluid is correct | amended, and it can suppress that drivability deteriorates.

  In the continuously variable transmission control apparatus according to the sixth aspect of the invention, in addition to the configuration of the fifth aspect of the invention, the predetermined cycle is a cycle according to the running state of the vehicle.

  According to the sixth aspect of the invention, for example, the running state of the vehicle is distinguished between a steady state that tends to be upshifted and a coast state that tends to be downshifted. The output cycle in which it is detected that hunting has occurred is set according to the running state. Thereby, it is possible to suppress the deterioration of drivability by detecting hunting according to the characteristics of the running state.

  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.

  With reference to FIG. 1, a power train of a vehicle including a control device according to the present embodiment will be described. The control apparatus according to the present embodiment is realized by ECT (Electronic Controlled Automatic Transmission) _ECU 900 shown in FIG.

As shown in FIG. 1, the power source 100 is connected to the speed change mechanism 200, and the output shaft 300 of the speed change mechanism 200 is connected to the left and right drive wheels 500 via the differential gear 400. Here, the power source 100 includes various power sources that can be used in the vehicle, such as an internal combustion engine such as a gasoline engine or a diesel engine, or an electric motor such as a motor, and a device that combines the internal combustion engine and the electric motor. In the following description, as a power source 100, fuel is directly injected into the cylinder, and the injection amount and timing are controlled, so that a so-called direct injection gasoline engine capable of homogeneous combustion or stratified combustion, or a throttle opening is electrically generated. An example in which a gasoline engine equipped with an electronic throttle valve that can be freely controlled will be described (hereinafter, the power source 100 will be referred to as the engine 100).

  The engine 100 is configured to be electrically controllable, and an engine ECU 800 mainly including a microcomputer for the control is provided. The engine ECU 800 is configured to control at least the output of the engine 100, and the output shaft rotational speed (engine rotational speed) NE and the requested output amount such as the accelerator opening PA are input as data for the control. Is done.

  This required output amount is a signal for increasing / decreasing the output of the engine 100, and the operation amount signal of the acceleration / deceleration operation device 700 such as an accelerator pedal operated by the driver and the operation amount are electrically processed. The obtained signal can be used, and in addition, it may be an output request amount signal from a cruise control system (not shown) for maintaining the vehicle speed at the set vehicle speed.

  The transmission mechanism 200 includes a fluid transmission mechanism 210, a forward / reverse switching mechanism 220, and a belt type continuously variable transmission (CVT) 230.

  The fluid transmission mechanism 210 is a device configured to transmit torque between an input-side member and an output-side member via a fluid such as oil, and is adopted as an example in a general vehicle. A torque converter can be mentioned. The fluid transmission mechanism 210 includes a lockup clutch 212. That is, the lock-up clutch 212 is a clutch configured to directly connect the input side member and the output side member by mechanical means such as a friction plate, and is an elastic body such as a coil spring for buffering. The damper 214 which consists of is provided.

  A hydraulic pump that is rotated by the engine 100 as a power source and has a discharge pressure that increases in accordance with the rotational speed is provided at a position close to the fluid transmission mechanism 210. Specifically, it is disposed between the fluid transmission mechanism 210 and the forward / reverse switching mechanism 220. When the fluid transmission mechanism 210 is provided in order to keep the engine 100 driven even when the vehicle is stopped, the automatic clutch that is automatically engaged and disengaged based on the state of the vehicle is The fluid transmission mechanism 210 can be used as a replacement.

  An input member of fluid transmission mechanism 210 is connected to an output member of engine 100, and an output member of fluid transmission mechanism 210 is connected to an input member of forward / reverse switching mechanism 220. This forward / reverse switching mechanism 220 is constituted by a double pinion type planetary gear mechanism as an example, and although not particularly shown, either one of the sun gear and the carrier is used as an input element and the other is used as an output element, and a ring gear is used. A brake element for selectively fixing, and a clutch element for integrating the entire planetary gear mechanism by selectively connecting any two of the three elements of the sun gear, the carrier, and the ring gear. That is, the forward state is set by engaging the clutch element, and the reverse state is set by engaging the brake element.

  A belt type continuously variable transmission 230 shown in FIG. 1 is a belt capable of continuously (continuously) changing the ratio of the rotation speed of the input side member and the rotation speed of the output side member, that is, the gear ratio. Type continuously variable transmission. An example of the belt type continuously variable transmission 230 will be described with reference to FIG.

A driving pulley (primary pulley) 232, a driven pulley (secondary pulley) 234, and a belt 236 wound around these pulleys 232 and 234 are provided . Each of the pulleys 232 and 234 includes a fixed sheave 238 and 240 and movable sheaves 242 and 244 that approach and separate from the fixed sheave 238 and 240. The movable sheaves 242 and 244 are fixed to the fixed sheaves 238 and 240. Are provided with hydraulic actuators 246 and 248 for pressing in the direction of approaching. These sheaves 238, 240, 242, and 244 form a V-groove belt winding groove (pulley groove) for winding the belt 236.

  A primary pulley 232 is attached to the input shaft 290, and a secondary pulley 234 is attached to the output shaft 300 disposed in parallel with the input shaft 290. The hydraulic actuator 248 in the secondary pulley 234 is supplied with hydraulic pressure corresponding to the required driving force obtained based on the output request typified by the accelerator pedal opening PA, and presses the movable sheave 244 toward the fixed sheave 240 side. By sandwiching the belt 236, a force necessary to transmit torque is applied to the belt 236.

  In addition, hydraulic oil is supplied to and discharged from the hydraulic actuator 246 of the primary pulley 232 so as to obtain a gear ratio that matches the rotational speed of the input shaft 290 with the target input rotational speed. That is, by changing the groove width (interval between the fixed sheaves 238 and 240 and the movable sheaves 242 and 244) in the pulleys 232 and 234, the wrapping radius of the belt 236 around the pulleys 232 and 234 is changed to be large or small. Shifting is executed.

  More specifically, the shift is executed by feedback-controlling the hydraulic oil of the primary pulley 232 based on the rotational speed deviation (control deviation) between the actual input rotational speed and the target input rotational speed, and thus the control deviation is large. The faster the speed is changed.

  With reference to FIG. 3, a hydraulic circuit that performs shift control will be described.

  The supply and discharge of hydraulic oil to and from the primary pulley 232 is performed by flow control. The valve mechanism for that purpose is configured as shown in FIG. That is, the hydraulic actuator 246 of the primary pulley 232 communicates with the first flow control valve 3100 that supplies the line pressure PL and the second flow control valve 3200 connected to the drain. The first flow control valve 3100 is a valve for executing an upshift, and a flow between the input port 3300 to which the line pressure PL is supplied and the output port 3400 communicated with the hydraulic actuator 246 of the primary pulley 232. The road is configured to be opened and closed by a spool 3500. A spring 3600 is disposed at one end of the spool 3500, and a first signal pressure port 3700 for applying a signal pressure is formed at an end opposite to the spring 3600 across the spool 3500. Yes. In addition, a second signal pressure port 3800 for applying a signal pressure to the one end side where the spring 3600 is disposed is formed.

  The first solenoid valve 3900 whose output pressure increases according to the duty is connected to the first signal pressure port 3700, and the second solenoid valve whose output pressure increases according to the duty is connected to the second signal pressure port 3800. 4000 is connected to each of the signal pressure ports 3700 and 3800 so that the signal pressure output from the solenoid valves 3900 and 4000 is applied thereto. That is, by increasing the hydraulic pressure applied to the first signal pressure port 3700 and opening the input port 3300, hydraulic oil is supplied from the output port 3400 to the hydraulic actuator 246 of the primary pulley 232, and the groove width of the primary pulley 232 is narrowed. As a result, the gear ratio is lowered. That is, it is upshifted. Further, by increasing the supply flow rate of hydraulic oil at that time, the speed change speed is increased.

The second flow control valve 3200 is a valve for executing a downshift, the first port 4100 communicating with the hydraulic actuator 246 of the primary pulley 232, pressure regulating as a source pressure to the line pressure PL The spool 4400 selectively communicates with the second port 4200 and the drain port 4300 to which the hydraulic pressure is supplied. A spring 4500 is disposed on one end of the spool 4400, and a first signal pressure port 4600 for applying a signal pressure is formed on the one end. A second signal pressure port 4700 for applying a signal pressure is formed at the end opposite to the spring 4500 across the spool 4400.

  The first solenoid valve 3900 is connected to the first signal pressure port 4600, and the second solenoid valve 4000 is connected to the second signal pressure port 4700. These solenoid valves are connected to the signal pressure ports 4600 and 4700, respectively. A signal pressure output by 3900, 4000 is applied. That is, by increasing the hydraulic pressure applied to the second signal pressure port 4700 and causing the first port 4100 to communicate with the drain port 4300, hydraulic oil is discharged from the hydraulic actuator 246 of the primary pulley 232, and the groove width of the primary pulley 232. As a result, the transmission ratio increases. That is, it is downshifted. Further, by increasing the discharge flow rate of the hydraulic oil at that time, the speed change speed is increased.

  Further, a pressure regulating valve 4800 is connected to the second port 4200 of the second flow control valve 3200. This pressure regulating valve 4800 has an input port 5100 to which a line pressure PL is supplied formed on the front side of the piston 5000 pressed by a spring 4900, and an output port communicating with the front side and the back side of the piston 5000. The output port 5200 communicates with the second port 4200 of the second flow rate control valve 3200. Further, the line pressure PL is supplied to the input port 5100 through a double orifice 5300 having a small opening area. That is, the pressure regulating valve 4800 is configured such that a hydraulic pressure having a pressure obtained by subtracting the elastic force of the spring 4900 from the line pressure PL is generated at the output port 5200, that is, the second port 4200 of the second flow rate control valve 3200.

  More specifically, when the first port 4100 and the second port 4200 of the second flow control valve 3200 are communicated with the input port 3300 of the first flow control valve 3100 being closed, the pressure regulating valve 4800 The hydraulic oil pressure-adjusted is supplied to the hydraulic actuator 246 of the primary pulley 232 via the second port 4200. In this case, the flow rate is a very small amount limited by the double orifice 5300. As a result, the hydraulic pressure of the hydraulic actuator 246 of the primary pulley 232 increases. However, since the hydraulic pressure of the hydraulic actuator acts on the back side of the piston 5000 in the pressure regulating valve 4800, the pressure is changed from the line pressure PL to the elastic force of the spring 4900. When the pressure is reduced, the piston 5000 is pressed toward the input port 5100 to close the input port 5100, and the hydraulic oil is prevented from being supplied any further. Therefore, in a so-called closed (in-place) state where hydraulic fluid is not supplied from the first flow control port 3100 to the hydraulic actuator 246 of the primary pulley 232 and is not discharged from the second flow control valve 3200, the hydraulic actuator 246 of the primary pulley 232 Is maintained at the hydraulic pressure regulated by the pressure regulating valve 4800 (pressure lower than the line pressure PL).

  Such a state of maintaining the hydraulic pressure is the same when an unavoidable oil leakage occurs during the closing control, and the hydraulic actuator of the primary pulley 232 is caused by the oil leakage from the hydraulic circuit or the hydraulic control device. When the hydraulic pressure of 246 decreases, hydraulic oil is supplied little by little from the input port 5100 of the pressure regulating valve 4800 to the hydraulic actuator 246 of the primary pulley 232, and the pressure regulated value by the pressure regulating valve 4800 is maintained. As a result, the shift state tends to be slightly upshifted, and the speed is gradually increased so that the gear ratio is gradually decreased.

In the belt-type continuously variable transmission 230, the speed ratio on the lowest speed side (maximum speed ratio: the maximum speed ratio: On the other hand, the belt 236 has a maximum winding radius with respect to the primary pulley 232 and a minimum winding radius of the belt 236 with respect to the secondary pulley 234. Ratio (minimum transmission ratio: maximum speed increase state) is set.

  Control of each state of engagement / release of the lockup clutch 212 in the transmission mechanism 200 and half-engagement with slipping, switching of the forward / reverse movement in the forward / reverse switching mechanism 220, and the transmission ratio of the belt-type continuously variable transmission 230 Basically, the control is performed based on the running state of the vehicle so as to improve the fuel consumption. For this control, an ECT_ECU 900 composed mainly of a microcomputer is provided.

  The ECT_ECU 900 is connected to the above-described engine ECU 800 so as to be able to perform data communication. On the other hand, as data for control, the ECT_ECU 900 is input as the vehicle speed, the input side rotational speed (actual input rotational speed NIN), and the output rotational speed (actual Data such as output rotation speed NOUT) is input. The rotation speed sensor 600 is a sensor that detects the rotation speed of the primary pulley 232, the secondary pulley 234, and the like in order to execute the shift control in the belt-type continuously variable transmission 230. When the pulse gear teeth (not shown) pass through the electromagnetic pickup, a pulse signal is generated in the electromagnetic pickup, and the actual input rotation speed NIN and the actual output rotation speed NOUT are based on the interval and width of the pulse signal. Is configured to ask for.

  The transmission mechanism 200 is automatically set in accordance with the stopped state (parking position: P position), reverse state (reverse position: R position), neutral state (neutral position: N position), and the running state of the vehicle. An automatic forward state in which normal travel is performed (drive position: D position), a state in which the pumping loss of the engine 100 is used as a braking force (brake position: B position), and a state in which the setting of a high-speed side gear ratio exceeding a predetermined value is prohibited. A shift device 1000 for selecting each state (position) of (SD position) is provided, and this shift device 1000 is electrically connected to the ECT_ECU 900.

  The ECT_ECU 900 also controls the duty ratio (duty command value) of the control signal to the first solenoid valve 3900 and the second solenoid valve 4000 and the hydraulic oil supplied and discharged from the first flow control valve 3100 and the second flow control valve 3200. A duty ratio-flow rate control output characteristic that is a relationship with the flow rate is stored in a memory (not shown).

  The ECT_ECU 900 calculates a duty ratio for obtaining a desired gear ratio based on the duty ratio-flow rate control output characteristic. However, the first flow control valve 3100, the second flow control valve 3200, the first solenoid valve 3900, and the second solenoid valve 4000 have individual differences due to manufacturing variations. Therefore, the flow rate of the hydraulic oil that is actually supplied and discharged may differ from the stored duty ratio-flow rate control output characteristic. In this case, learning correction of the stored duty ratio-flow rate control output characteristic is performed.

  In order to perform the learning correction of the duty ratio-flow rate control output characteristic, the ECT_ECU 900 calculates the estimated amount of change in the hydraulic oil capacity of the hydraulic actuator 246 in the time from the start of the shift to the end of the shift or the predetermined time during the shift To do. The estimated value of the change amount of the hydraulic oil capacity is calculated in consideration of the duty ratio using the physical models of the first flow control valve 3100 and the second flow control valve 3200. The physical model is stored in the memory. In addition, about the method of calculating the variation | change_quantity estimated value of hydraulic fluid capacity | capacitance, what is necessary is just to use a known general technique, Therefore Here, detailed description is not repeated.

  The ECT_ECU 900 calculates the amount of movement of the movable sheave 242 of the primary pulley 232 from the amount of change in the gear ratio during the time from the start of the shift to the end of the shift or the predetermined time during the shift. Based on the amount of movement of the movable sheave 242, the ECT_ECU 900 calculates a change amount detection value of the hydraulic oil capacity of the hydraulic actuator 246 in the time from the start of the shift to the end of the shift or a predetermined time during the shift.

  The ECT_ECU 900 learns and corrects the duty ratio-flow rate control output characteristic based on the deviation between the detected value and the estimated value of the hydraulic oil capacity. Thereby, the followability of the actual speed ratio with respect to the target speed ratio can be improved.

  However, the physical model stored in the memory does not necessarily match the actual first flow control valve 3100 and the second flow control valve 3200. Therefore, an error is included in the estimated change amount of the hydraulic oil capacity. If the duty ratio-flow rate control output characteristics are learned and corrected based on such an estimated value, there is a risk of erroneous learning.

  Incidentally, in the belt type continuously variable transmission 230, the hydraulic actuator 246 is controlled so that the actual input rotational speed NIN of the primary pulley 232 coincides with the target input rotational speed NINT. Here, if the duty ratio is calculated based on the erroneously learned duty ratio-flow rate control output characteristic to control the first solenoid valve 3900 and the second solenoid valve 4000, the operation amount of the hydraulic actuator 246 becomes excessively large, Responsiveness may become excessively good.

  In such a case, the actual input rotational speed NIN does not match the target input rotational speed NINT. Therefore, as shown in FIG. 4, the output of the control signal from the ECT_ECU 900 to the first solenoid valve 3900 and the output of the control signal to the second solenoid valve 4000 hunt in a short cycle (0 to 50 msec) (alternately Output).

  Further, as shown in FIG. 5, the output of the control signal from the ECT_ECU 900 to the first solenoid valve 3900 and the output of the control signal to the second solenoid valve 4000 are hunted at an intermediate period (about 200 msec).

  Thereby, shift hunting in which the actual input rotational speed NIN repeats overshoot and undershoot with respect to the target input rotational speed NINT occurs. When shift hunting occurs, the actual input rotational speed NIN of the primary pulley 232 periodically increases and decreases, so the output rotational speed of the secondary pulley 234, that is, the vehicle speed, periodically increases and decreases. As a result, longitudinal vibrations occur in the vehicle, and drivability deteriorates. ECT_ECU 900 of the control device according to the present embodiment suppresses shift hunting due to erroneous learning of the duty ratio-flow rate control output characteristic.

  With reference to FIG. 6, a control structure of a program executed by ECT_ECU 900 of the control device according to the present embodiment will be described. Note that the program described below is repeatedly executed at a predetermined cycle.

  In step (hereinafter, step is abbreviated as S) 100, ECT_ECU 900 performs duty command value for solenoid valve, accelerator opening, brake signal, engine speed, actual input shaft speed NIN, actual output speed NOUT, and estimation. Get input torque information. Information on the accelerator opening and the brake signal is transmitted from the acceleration / deceleration operating device 700 to the ECT_ECU 900 via the engine ECU 800. The engine speed is transmitted from engine ECU 800 to ECT_ECU 900. The estimated input torque is calculated from the map by the ECT_ECU 900 based on the engine speed.

  In S200, ECT_ECU 900 determines whether the traveling state of the vehicle is a steady state based on the acquired information. As a method for determining whether or not it is in a steady state, a well-known general technique may be used. Therefore, detailed description thereof will not be repeated here. If it is in a steady state (YES in S200), the process proceeds to S202. If not (NO in S200), the process proceeds to S300.

  In S202, ECT_ECU 900 outputs the control signal output time when the output of the control signal to first solenoid valve 3900 and the output of the control signal to second solenoid valve 4000 are hunted within a predetermined time ΔT. The number of times A that TO is longer than a predetermined time TA (MIN) and shorter than a predetermined time TA (MAX) is counted. That is, the ECT_ECU 900 counts the number A of times that the hunting cycle is longer than the predetermined time TA (MIN) and shorter than the predetermined time TA (MAX) within the predetermined time ΔT. To do. In the present embodiment, TA (MIN) is set to 0 msec and TA (MAX) is set to 50 msec.

  In S204, ECT_ECU 900 determines whether or not counted number A is greater than a predetermined number A (0). If counted number A is greater than predetermined number A (0) (YES in S204), the process proceeds to S206. If not (NO in S204), the process proceeds to S208.

  In addition, instead of or in addition to the condition that the counted number A is greater than the predetermined number A (0), the duty command value (duty ratio) when hunting is greater than a predetermined value. If larger, the process may be moved to S206.

  In S206, ECT_ECU 900 corrects the duty ratio-flow rate control output characteristic stored in the memory, and corrects the operation amount of hydraulic actuator 246. At this time, assuming that the correction amount of the hydraulic actuator 246 is GA, the duty ratio-flow rate control output characteristic is corrected so that the response of the hydraulic actuator 246 is suppressed.

  In S208, ECT_ECU 900 outputs the control signal output time when the output of the control signal to first solenoid valve 3900 and the output of the control signal to second solenoid valve 4000 are hunted within a predetermined time ΔT. TO is longer than a predetermined time TB (MIN) (TB (MIN)> TA (MIN)) and shorter than a predetermined time TB (MAX) (TB (MAX)> TA (MAX)). Count the number of times B. That is, the ECT_ECU 900 counts the number of times B in which the hunting period is longer than the predetermined time TB (MIN) and shorter than the predetermined time TB (MAX) within the predetermined time ΔT. To do. In the present embodiment, TB (MIN) is set to 150 msec, and TB (MAX) is set to 250 msec.

  In S210, ECT_ECU 900 determines whether or not the counted number B is larger than a predetermined number B (0). If the counted number B is greater than a predetermined number B (0) (YES in S210), the process proceeds to S212. If not (NO in S210), this process ends.

  In addition, instead of or in addition to the condition that the counted number B is greater than the predetermined number B (0), the duty command value (duty ratio) when hunting is greater than a predetermined value. If larger, the process may be moved to S212.

  In S212, ECT_ECU 900 corrects the duty ratio-flow rate control output characteristic stored in the memory, and corrects the operation amount of hydraulic actuator 246. At this time, the correction amount of the hydraulic actuator 246 is GB (GA> GB), and the duty ratio-flow rate control output characteristic is corrected so that the response of the hydraulic actuator 246 is suppressed.

At S300, ECT_ECU900 based on the acquired information, the traveling state of the vehicle is equal to or a course bets state. As a method for determining whether or not the coasting state is used, a well-known general technique may be used. Therefore, detailed description thereof will not be repeated here. If it is in the coast state (YES in S300), the process proceeds to S302. If not (NO in S300), this process ends.

  In S302, the ECT_ECU 900 outputs the control signal output time when the output of the control signal to the first solenoid valve 3900 and the output of the control signal to the second solenoid valve 4000 are hunted within a predetermined time ΔT. The number of times C in which TO is longer than a predetermined time TC (MIN) and shorter than a predetermined time TC (MAX) is counted. That is, the ECT_ECU 900 counts the number C of times that the hunting cycle is longer than the predetermined time TC (MIN) and shorter than the predetermined time TC (MAX) within the predetermined time ΔT. To do.

  TC (MIN) may be the same value as TA (MIN), or may be set to a value different from TA (MIN) according to the output characteristics of the control signal in the coast state. Similarly, TC (MAX) may be the same value as TA (MAX), or may be set to a value different from TA (MAX) according to the output characteristics of the control signal in the coast state.

  In S204, ECT_ECU 900 determines whether or not the counted number C is greater than a predetermined number C (0) (C (0) <A (0)). If the counted number C is greater than the predetermined number C (0) (YES in S304), the process proceeds to S306. If not (NO in S304), the process proceeds to S308.

  It should be noted that the duty command value (duty ratio) at the time of hunting is greater than a predetermined value in place of or in addition to the condition that the counted number C is greater than the predetermined number C (0). If it is larger, the process may be moved to S306.

  In S306, ECT_ECU 900 corrects the duty ratio-flow rate control output characteristic stored in the memory and corrects the operation amount of hydraulic actuator 246. At this time, assuming that the correction amount of the hydraulic actuator 246 is GC, the duty ratio-flow rate control output characteristic is corrected so that the response of the hydraulic actuator 246 is suppressed. The correction amount GC may be the same value as the correction amount GA, or may be set to a value different from the correction amount GA according to the output characteristics of the control signal in the coast state.

  In S308, ECT_ECU 900 outputs the control signal output time when the output of the control signal to first solenoid valve 3900 and the output of the control signal to second solenoid valve 4000 are hunted within a predetermined time ΔT. TO is longer than a predetermined time TD (MIN) (TD (MIN)> TC (MIN)) and shorter than a predetermined time TD (MAX) (TD (MAX)> TC (MAX)). Count the number of times D. That is, the ECT_ECU 900 counts the number D of times that the hunting cycle is longer than the predetermined time TD (MIN) and shorter than the predetermined time TD (MAX) within the predetermined time ΔT. To do.

  TD (MIN) may be the same value as TB (MIN), or may be set to a value different from TB (MIN) according to the output characteristics of the control signal in the coast state. Similarly, TD (MAX) may be the same value as TB (MAX), or may be set to a value different from TB (MAX) according to the output characteristics of the control signal in the coast state.

  In S310, ECT_ECU 900 determines whether or not the counted number D is greater than a predetermined number D (0) (D (0) <B (0)). If the counted number D is greater than a predetermined number D (0) (YES in S310), the process proceeds to S312. If not (NO in S310), this process ends.

  In addition, instead of or in addition to the condition that the counted number of times D is larger than the predetermined number of times D (0), the duty command value (duty ratio) when hunting is greater than a predetermined value. If larger, the process may be moved to S312.

  In S312, ECT_ECU 900 corrects the duty ratio-flow rate control output characteristic stored in the memory and corrects the operation amount of hydraulic actuator 246. The correction amount of the hydraulic actuator 246 is GD (GD> GC), and the duty ratio-flow rate control output characteristic is corrected so that the response of the hydraulic actuator 246 is suppressed. The correction amount GD may be the same value as the correction amount GB, or may be set to a value different from the correction amount GB according to the output characteristics of the control signal in the coast state.

  An operation of ECT_ECU 900 of the control device in the present embodiment based on the above-described structure and flowchart will be described.

  Information required to detect shift hunting while the vehicle is running includes duty command value to solenoid valve, accelerator opening, brake signal, engine speed, actual input shaft speed NIN, output speed and estimated input Torque information is acquired.

  Based on the acquired information, it is determined whether the running state of the vehicle is a steady state (S200). In the steady state (YES in S200), the output time TO when the output of the control signal is hunted within a predetermined time ΔT in order to determine whether or not a short-cycle shift hunting has occurred. However, the number of times A that is longer than the predetermined time TA (MIN) and shorter than the predetermined time TA (MAX) is counted (S202).

  Like the time ΔT from time T (1) to time T (2) and the time ΔT from time T (2) to time T (3) in FIG. 7, the counted number of times A is a predetermined number of times. If it is less than A (0) (NO in S204), the duty ratio-flow rate control output characteristic correction, that is, the operation amount of hydraulic actuator 246 is not corrected.

  On the other hand, when the counted number of times A is greater than the predetermined number of times A (0), such as time ΔT from time T (3) to time T (4) (YES in S204), the hydraulic actuator Using the correction amount of 246 as GA, the duty ratio-flow rate control output characteristic is corrected so that the response of the hydraulic actuator 246 is suppressed (S206). Thereby, the operation amount of the hydraulic actuator 246 is reduced, the responsiveness is suppressed, and the occurrence of shift hunting is suppressed.

  Further, in order to determine whether or not middle-cycle shift hunting has occurred, the control signal output time TO when the control signal output is hunted within a predetermined time ΔT is a predetermined time. The number of times B that is longer than TB (MIN) and shorter than a predetermined time TB (MAX) is counted (S208).

  If the number of times B counted within the predetermined time ΔT is smaller than the predetermined number of times B (0) (NO in S210), since middle-cycle shift hunting has not occurred, the duty ratio − The flow rate control output characteristics are not corrected.

  On the other hand, when the number of times B counted within a predetermined time ΔT is greater than the predetermined number of times B (0) (YES in S210), a middle-cycle shift hunting has occurred, so the hydraulic actuator With the correction amount of 246 as GB, the duty ratio-flow rate control output characteristic is corrected so that the response of the hydraulic actuator 246 is suppressed (S212). Thereby, the operation amount of the hydraulic actuator 246 is reduced, the responsiveness is suppressed, and the occurrence of shift hunting is suppressed.

  The response of the hydraulic actuator 246 when the medium-cycle shift hunting occurs is lower than the response when the short-cycle shift hunting occurs. Therefore, the correction amount GB of the hydraulic actuator 246 when the medium-cycle shift hunting occurs may be smaller than the correction amount GA when the short-cycle shift hunting occurs.

  When the running state of the vehicle is a steady state, the belt type continuously variable transmission 230 is controlled so as to improve the fuel consumption, and therefore the frequency of upshifting is higher than the frequency of downshifting. Therefore, when the duty ratio-flow rate control output characteristic is corrected in the steady state, it is effective when the duty ratio-flow rate control output characteristic is erroneously learned so that the operation amount of the hydraulic actuator 246 is excessively increased on the upshift side. is there.

  On the other hand, when the running state of the vehicle is a coast state (NO in S200, YES in S300), in the same way as in the steady state, it is determined in advance to determine whether short-cycle shift hunting has occurred. Within the predetermined time ΔT, the output time TO of the control signal when the output of the control signal is hunted is longer than the predetermined time TC (MIN) and shorter than the predetermined time TC (MAX). The number of times C is counted (S302).

  When the number of times C counted within the predetermined time ΔT is smaller than the predetermined number of times C (0) (NO in S304), correction of the duty ratio-flow rate control output characteristic, that is, the hydraulic actuator 246 The operation amount is not corrected.

  If the number of times C counted within the predetermined time ΔT is greater than the predetermined number of times C (0) (YES in S304), the response amount of the hydraulic actuator 246 is set to GC as the correction amount of the hydraulic actuator 246. The duty ratio-flow rate control output characteristic is corrected so that the characteristics are suppressed (S306). As a result, the amount of operation of the hydraulic actuator 246 is reduced, responsiveness is suppressed, and occurrence of short-cycle shift hunting is suppressed.

  Further, in order to determine whether or not middle-cycle shift hunting has occurred, the output time TO of the control signal when the control signal is hunted at a predetermined time ΔT is set to a predetermined time TB (MIN). The number of times D that is longer and shorter than the predetermined time TB (MAX) is counted (S308).

  If the number of times D counted within the predetermined time ΔT is smaller than the predetermined number of times D (0) (YES in S310), since middle-cycle shift hunting has not occurred, the duty ratio − The flow rate control output characteristics are not corrected.

  On the other hand, if the number of times D counted within a predetermined time ΔT is greater than the predetermined number of times D (0) (YES in S210), the middle cycle shift hunting has occurred, so the hydraulic pressure Using the correction amount of the actuator 246 as GD, the duty ratio-flow rate control output characteristic is corrected so that the response of the hydraulic actuator 246 is suppressed (S312). As a result, the amount of operation of the hydraulic actuator 246 is reduced, responsiveness is suppressed, and occurrence of short-cycle shift hunting is suppressed.

  The response of the hydraulic actuator 246 when the medium-cycle shift hunting occurs is lower than the response when the short-cycle shift hunting occurs. Therefore, the correction amount GD of the hydraulic actuator 246 when the medium-cycle shift hunting occurs may be smaller than the correction amount GC when the short-cycle shift hunting occurs.

  When the running state of the vehicle is a coast state, the frequency of downshift is greater than the frequency of upshift as the vehicle speed decreases. Therefore, when the duty ratio-flow rate control output characteristic is corrected in the coast state, it is effective when the duty ratio-flow rate control output characteristic is erroneously learned so that the operation amount of the hydraulic actuator 246 is excessively increased on the downshift side. is there.

  As described above, the ECT_ECU of the control device according to the present embodiment allows the output time TO of the control signal when the output of the control signal hunts within the predetermined time ΔT to be within a predetermined time range. Count the number of times it was in. If the counted number is greater than the predetermined number, the ECT_ECU corrects the duty ratio-flow rate control output characteristic so that the response of the hydraulic actuator is suppressed. Thereby, the operation amount of the hydraulic actuator is reduced, the responsiveness is suppressed, and the occurrence of shift hunting is suppressed.

  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 control block diagram of the control apparatus which concerns on embodiment of this invention. FIG. 2 is a detailed view of the CVT shown in FIG. 1. It is a figure which shows a part of hydraulic circuit for the transmission control of CVT. It is a figure which shows the control signal output to a solenoid valve from ECT_ECU in a short cycle. It is a figure which shows the control signal output to a solenoid valve from ECT_ECU with a medium period. It is a figure which shows the control structure of the program performed by ECU of the control apparatus which concerns on embodiment of this invention. It is a timing chart which shows the control signal output to a solenoid valve from ECT_ECU when the driving | running | working state of a vehicle is a steady state.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 Engine, 200 Transmission mechanism, 210 Fluid transmission mechanism, 212 Lock-up clutch, 214 Damper, 220 Forward / reverse switching mechanism, 232 Primary pulley, 234 Secondary pulley, 236 Belt, 290 Input shaft, 300 Output shaft, 400 Differential gear, 500 Drive wheel, 600 revolution speed sensor, 700 acceleration / deceleration operation device, 800 engine ECU, 900 ECT_ECU, 1000 shift device, 3100 first flow control valve, 3200 second flow control valve, 3900, 4000 solenoid valve, 4800 pressure regulating valve.

Claims (5)

A control device for a continuously variable transmission mounted on a vehicle, wherein a speed ratio of the continuously variable transmission is controlled by hydraulic oil, and a flow rate of the hydraulic oil is controlled by an electromagnetic valve,
Control means for controlling the solenoid valve by transmitting a control signal to the solenoid valve based on predetermined information relating to the flow rate of hydraulic oil;
Detecting means for detecting the number of times of hunting of the control signal;
Correction means for correcting the predetermined information based on the number of hunting times of the control signal in a predetermined period,
Said correction means hunting number of the control signal in a period in which said predetermined found if more than a predetermined number of times, so as to suppress the responsiveness in controlling the gear ratio, and of the control signal It is determined whether a hunting cycle is a first cycle or a second cycle longer than the first cycle, and the degree of suppression of the responsiveness when hunting occurs in the second cycle is A control device for a continuously variable transmission, including means for correcting the predetermined information so as to be smaller than the degree of suppression of the responsiveness at the time of occurrence of the first cycle . The control device for a continuously variable transmission according to claim 1 , wherein the correction means includes means for correcting the predetermined information in accordance with a traveling state of the vehicle. The continuously variable transmission according to claim 1 or 2 , wherein the detecting means includes means for detecting that hunting has occurred when an output cycle of the control signal is within a predetermined cycle range. Control device. The control device for a continuously variable transmission according to claim 3 , wherein the predetermined cycle is a cycle according to a traveling state of the vehicle. A control device for a continuously variable transmission mounted on a vehicle, wherein a speed ratio of the continuously variable transmission is controlled by hydraulic oil, and a flow rate of the hydraulic oil is controlled by an electromagnetic valve,
Control means for controlling the solenoid valve by transmitting a control signal to the solenoid valve based on predetermined information relating to the flow rate of hydraulic oil;
Detecting means for detecting the number of times of hunting of the control signal;
Correction means for correcting the predetermined information based on the number of hunting times of the control signal in a predetermined period,
The detection means includes means for detecting that hunting has occurred when the output period of the control signal is within a predetermined period range;
The control device for a continuously variable transmission, wherein the predetermined cycle is a cycle according to a traveling state of the vehicle.

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