JP2010261518A - Control device for vehicle provided with belt-type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for a vehicle provided with a belt-type continuously variable transmission, preventing a driver from feeling uncomfortable caused by drawing feeling. <P>SOLUTION: When deceleration is started by putting on a brake, hydraulic pressure higher than a belt clamping force, required in an area where a belt does not slip, is output, the belt clamping force is gradually reduced according as the vehicle stops, and a change in a longitudinal G value immediately before performing a lock-up OFF state from a lock-up ON state is eliminated, thereby suppressing the drawing feeling. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a control device for a vehicle including a belt-type continuously variable transmission (CVT: Continuously Variable Transmission).

  A belt-type continuously variable transmission applied to a power transmission device for an automobile has a primary pulley with a variable pulley groove width provided on a primary shaft on a driving side and a belt that is stretched between the primary pulley and a driven belt. And a secondary pulley with a variable pulley groove width provided on the secondary shaft on the side. If the ratio of the winding diameter of the belt to these pulleys, that is, the pulley ratio is changed by hydraulic pressure, the rotational speed of the secondary shaft can be changed steplessly.

  The shift control of the belt type continuously variable transmission is performed by adjusting the hydraulic pressure supplied to the drive oil chambers of the hydraulic cylinders provided in the primary pulley and the secondary pulley, respectively. The hydraulic pressure applied to is generated by an oil pump driven by an engine or an electric motor. The secondary pressure applied to the drive oil chamber on the secondary pulley side is regulated by the secondary pressure adjustment valve, and the primary pressure applied to the drive oil chamber on the primary pulley side is regulated by the primary pressure adjustment valve using the secondary pressure as the original pressure. Is done.

  In such a belt type continuously variable transmission, the fastening force (clamping pressure) of the primary pulley to the belt is weakened during deceleration to widen the groove width of the primary pulley, and the belt may slip with respect to the primary pulley. .

  Therefore, as disclosed in Patent Document 1, a target shift speed is set based on the throttle opening during deceleration, and the primary pressure and the secondary pressure are corrected from the target shift speed.

  Thus, even if the primary pressure and the secondary pressure are corrected uniformly based on the throttle opening for the entire rotation range of the primary pulley, the foot brake is depressed by the driver under the low-speed traveling state. Then, the belt may slip greatly in the radial direction with respect to the primary pulley, and gloss slip may occur.

  The reason for this is that the region where there is no gloss slip between the belt and the pulley during gear shifting, that is, the gear shifting speed at which gear shifting can be performed without gloss slip is proportional to the rotation speed of the primary pulley. Because it becomes late. For this reason, the foot brake is stepped on to a very low speed state, and the primary pulley rotation speed suddenly decreases despite the downshift. Will slip gross. As a result, when the vehicle stops, the inertia force of the primary pulley propagates to the vehicle and a shock is generated. This phenomenon was prominent when the gear ratio was on the large side (LOW side).

  Therefore, Patent Document 2 proposes a technique that prevents the belt from slipping even when the vehicle speed is extremely low due to sudden deceleration and the rotation speed of the primary pulley suddenly decreases.

  In the belt-type continuously variable transmission described in Patent Document 2, the ratio of the belt winding diameter changes by adjusting the primary pressure supplied to the primary pulley and the secondary pressure supplied to the secondary pulley. When the number of revolutions of the primary pulley is equal to or lower than the predetermined value, the vehicle speed is equal to or lower than the predetermined value, and the vehicle deceleration is higher than the predetermined value, the primary pressure is set to a higher pressure, the secondary pressure is increased and the primary pressure is increased. By setting the pressure higher according to the secondary pressure, increasing the secondary pressure according to the decrease in the rotation speed of the primary pulley, or setting the secondary pressure and the primary pressure higher, the belt during sudden deceleration Prevents gross slip.

JP 2000-97321 A JP 2002-327835 A

  In general belt-type continuously variable transmissions, hydraulic pressure is controlled so as to output a hydraulic pressure at which the belt does not slip during deceleration, and to return the belt to LOW when the brake is ON. That is, the hydraulic control considering the feeling of deceleration is not performed.

  In order to improve fuel efficiency, belt-type continuously variable transmissions are locked up to low vehicle speeds and fail cut. As a result, the lockup is turned on and the fail cut state is established with the LOW gear, and the deceleration G increases. As a result, the change in front and rear G is large immediately before the lockup is turned off, and a feeling of pulling in is felt.

  This is because when the speed is reduced in the lock-up ON and fail-cut state, the speed change of the belt-type continuously variable transmission is controlled so that the input rotation speed of the belt-type continuously variable transmission becomes constant, so that the gear ratio becomes LOW. Go (get bigger). Therefore, even if the friction torque is constant, the friction torque on the axis of the drive shaft increases as the vehicle speed decreases. Further, the belt clamping pressure of the belt-type continuously variable transmission has a higher required hydraulic pressure when the gear ratio is LOW (larger), so the belt clamping pressure needs to be increased as the vehicle speed decreases. Therefore, the friction torque on the input shaft also increases as the vehicle speed decreases. As a result, the deceleration G changes just before the lock-up is turned off, and a feeling of pulling in is felt.

  Such a sense of incongruity due to the pull-in feeling is caused by increasing the belt clamping pressure during braking and increasing the belt clamping pressure as the gear ratio changes to the low (LOW) side. It can also occur in a machine.

  The reason for this is that if the belt clamping pressure is increased, the friction torque increases, so the deceleration of the vehicle increases. However, when the above control is performed, the deceleration increases even if the brake pedal force does not change. Because it becomes. Therefore, there is a possibility of giving a sense of incongruity.

  The present invention has been made in view of the above technical problem, and an object of the present invention is to provide a vehicle control device including a belt-type continuously variable transmission that does not give the driver a sense of incongruity due to a feeling of being pulled.

  In order to achieve the above object, the present inventor has (1) In the belt type continuously variable transmission, when the vehicle is decelerated and stopped by the foot brake, the lockup OFF vehicle speed is pulled to a low speed. G changes to cause a sense of incongruity due to a feeling of pulling in, and (2) during deceleration stop, the speed ratio of the belt-type continuously variable transmission is changed toward the maximum speed ratio γmax side. Focusing on the fact that it is necessary to increase the clamping pressure (line pressure), and that this promotes the feeling of pulling in. When deceleration is started with the brake turned on, hydraulic pressure greater than the necessary belt clamping pressure is output within the range where the belt does not slip As the belt stops, the belt clamping pressure is gradually reduced to eliminate the change in the front and rear G immediately before the lock-up is turned off to suppress the pull-in feeling. The idea that it would be may be Re.

  The specific invention based on this idea is as follows.

  A control apparatus for a vehicle including a belt-type continuously variable transmission according to the present invention includes a belt-type continuously variable transmission having a pair of pulleys having variable groove widths and belts wound around these pulleys. A control device for detecting whether or not a speed reduction operation has been performed, and a speed ratio determining means for determining whether or not the gear ratio is shifted to a larger speed ratio, based on the rotation ratio of both pulleys. In a partial period during which the speed reduction operation detecting means and the speed ratio determining means determine that the gear ratio is shifted to the larger side and the speed reduction operation is detected by the speed reduction operation detecting means. Control means for gradually decreasing the clamping pressure after increasing the clamping pressure.

  The speed change can be suppressed by gradually decreasing the belt clamping pressure after increasing the belt clamping pressure in a part of the period during which the gear ratio is shifted to the larger side and the deceleration operation is detected. Therefore, the driver does not feel uncomfortable due to the pull-in.

  In the vehicle control device including the belt type continuously variable transmission, the control unit increases the belt clamping pressure immediately after detecting that the deceleration operation is performed by the deceleration operation detection unit, and then decreases the belt clamping pressure.

  Immediately after detecting that the deceleration operation has been performed, the belt clamping pressure is increased and then decreased, so that the deceleration change caused by the driver's deceleration operation and the deceleration change due to the belt clamping pressure change are changed. It will be performed almost simultaneously. Therefore, the driver does not feel a change in deceleration caused by a change in belt clamping pressure.

  In the control apparatus for a vehicle including the belt type continuously variable transmission, the control unit sets the belt clamping pressure while the deceleration operation is detected by the deceleration operation detecting unit to be smaller as the gear ratio is larger. To do.

  According to the present invention, it is possible to provide a control device for a vehicle including a belt-type continuously variable transmission that does not give the driver a sense of incongruity due to a feeling of being pulled.

1 is a schematic configuration diagram of a vehicle to which a control device according to an embodiment of the present invention is applied. It is a hydraulic control circuit block diagram which controls the hydraulic pressure of the hydraulic actuator of the primary pulley of a belt type continuously variable transmission, and the hydraulic actuator of a secondary pulley among hydraulic control circuits. It is a block diagram which shows the structure of control systems, such as ECU. It is a figure which shows a thrust ratio map. It is a figure which shows the relationship between a primary sheave hydraulic pressure and a secondary sheave hydraulic pressure, and a line pressure. It is a flowchart which shows the flow of control of belt clamping pressure control. It is a figure which shows P0 map. It is a figure which shows a Pup map. It is a timing chart which shows the control contents of belt clamping pressure control. It is a timing chart which shows the control contents of belt clamping pressure control when deceleration is large. It is a timing chart which shows the control contents of belt clamping pressure control when deceleration is small.

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

  FIG. 1 is a schematic configuration diagram of a vehicle to which a control device according to an embodiment of the present invention is applied.

  The vehicle shown in FIG. 1 is an FF (front engine / front drive) type vehicle, and includes an engine 1, a torque converter 2, a forward / reverse switching device 3, a belt-type continuously variable transmission 4, a reduction gear device 5, A dynamic gear device 6 and an ECU (Electronic Control Unit) 8 are mounted.

  A crankshaft 11 that is an output shaft of the engine 1 is connected to the torque converter 2, and the output of the engine 1 is transmitted from the torque converter 2 to the forward / reverse switching device 3, the belt type continuously variable transmission 4, and the reduction gear device 5. To the differential gear device 6 and distributed to the left and right drive wheels (not shown).

<Engine>
The engine 1 is, for example, a multi-cylinder gasoline engine. The amount of intake air taken into the engine 1 is adjusted by an electronically controlled throttle valve 12. The throttle valve 12 can electronically control the throttle opening independently of the driver's accelerator pedal operation, and the opening (throttle opening) is detected by the throttle opening sensor 102. . Further, the coolant temperature of the engine 1 is detected by a water temperature sensor 103.

  The throttle opening of the throttle valve 12 is driven and controlled by the ECU 8. Specifically, the optimum intake air amount (target) according to the operating state of the engine 1 such as the engine speed Ne detected by the engine speed sensor 101 and the accelerator pedal depression amount (accelerator operation amount) Acc of the driver. The throttle opening of the throttle valve 12 is controlled so that the intake amount) is obtained. More specifically, the actual throttle opening of the throttle valve 12 is detected using the throttle opening sensor 102, and the actual throttle opening coincides with the throttle opening (target throttle opening) at which the target intake air amount can be obtained. Thus, the throttle motor 13 of the throttle valve 12 is feedback-controlled.

<Torque converter>
The torque converter 2 includes a pump impeller 21 on the input shaft side, a turbine runner 22 on the output shaft side, a stator 23 that develops a torque amplification function, and a one-way clutch 24, and is provided between the pump impeller 21 and the turbine runner 22. The power is transmitted through the fluid.

  The torque converter 2 is provided with a lockup clutch 25 that directly connects the input side and the output side of the torque converter 2. The lockup clutch 25 has a differential pressure (lockup differential pressure) ΔP between the hydraulic pressure in the engagement side oil chamber 26 and the hydraulic pressure in the release side oil chamber 27 (ΔP = hydraulic pressure in the engagement side oil chamber 26 minus the release side). A hydraulic friction clutch that is frictionally engaged with the front cover 2a by the hydraulic pressure in the oil chamber 27, and controls the differential pressure ΔP to fully engage / semi-engage (engagement in a slip state). Or released.

  By completely engaging the lockup clutch 25, the pump impeller 21 and the turbine runner 22 rotate integrally. Further, by engaging the lockup clutch 25 in a predetermined slip state (half-engaged state), the turbine runner 22 rotates following the pump impeller 21 with a predetermined slip amount during driving. On the other hand, the lockup clutch 25 is released by setting the lockup differential pressure ΔP to be negative.

  The torque converter 2 is provided with a mechanical oil pump 7 that is connected to and driven by the pump impeller 21.

<Forward / backward switching device>
The forward / reverse switching device 3 includes a double pinion type planetary gear mechanism 30, a forward clutch C1, and a reverse brake B1.

  The sun gear 31 of the planetary gear mechanism 30 is integrally connected to the turbine shaft 28 of the torque converter 2, and the carrier 33 is integrally connected to the input shaft 40 of the belt type continuously variable transmission 4. The carrier 33 and the sun gear 31 are selectively connected via the forward clutch C1, and the ring gear 32 is selectively fixed to the housing 3a via the reverse brake B1.

  The forward clutch C1 and the reverse brake B1 are hydraulic friction engagement elements that are engaged / released by the hydraulic control circuit 20, and the forward clutch C1 is engaged and the reverse brake B1 is released. As a result, the forward / reverse switching device 3 is integrally rotated to establish the forward power transmission path, and in this state, the forward driving force is transmitted to the belt type continuously variable transmission 4 side.

  On the other hand, when the reverse brake B1 is engaged and the forward clutch C1 is released, the forward / reverse switching device 3 establishes a reverse power transmission path. In this state, the input shaft 40 rotates in the reverse direction with respect to the turbine shaft 27, and the driving force in the reverse direction is transmitted to the belt type continuously variable transmission 4 side. Further, when both the forward clutch C1 and the reverse brake B1 are released, the forward / reverse switching device 3 is in a neutral state (blocking state) for blocking power transmission.

<Belt type continuously variable transmission>
The belt-type continuously variable transmission 4 includes an input-side primary pulley 41, an output-side secondary pulley 42, and a metal belt 43 wound between the primary pulley 41 and the secondary pulley 42. .

  The primary pulley 41 is a variable pulley having a variable effective diameter, and a fixed sheave 411 fixed to the input shaft 40 and a movable sheave 412 disposed on the input shaft 40 in a state in which sliding is possible only in the axial direction. And is composed of. Similarly to the primary pulley 41, the secondary pulley 42 is a variable pulley having a variable effective diameter, and a fixed sheave 421 fixed to the output shaft 44 and a state in which the output shaft 44 can slide only in the axial direction. The movable sheave 422 is provided.

  A hydraulic actuator 413 for changing the V groove width between the fixed sheave 411 and the movable sheave 412 is disposed on the movable sheave 412 side of the primary pulley 41. Similarly, a hydraulic actuator 423 for changing the V groove width between the fixed sheave 421 and the movable sheave 422 is also arranged on the movable sheave 422 side of the secondary pulley 42.

  In the belt type continuously variable transmission 4 having the above-described structure, by controlling the hydraulic pressure of the hydraulic actuator 413 of the primary pulley 41, the V groove widths of the primary pulley 41 and the secondary pulley 42 change, and the engagement diameter of the belt 43 ( The effective gear ratio) is changed, and the gear ratio γ (γ = primary pulley rotation speed (input shaft rotation speed) Nin / secondary pulley rotation speed (output shaft rotation speed) Nout) continuously changes. The hydraulic pressure of the hydraulic actuator 423 of the secondary pulley 42 is controlled such that the belt 43 is clamped with a predetermined clamping pressure that does not cause belt slip. These controls are executed by the ECU 8 and the hydraulic control circuit 20.

<Hydraulic control circuit>
Next, in the hydraulic control circuit 20, the hydraulic control circuit of the hydraulic actuator 413 of the primary pulley 41 of the belt type continuously variable transmission 4, the hydraulic control circuit of the hydraulic actuator 423 of the secondary pulley 42, etc. will be described with reference to FIG. I will explain.

  The hydraulic control circuit 20 shown in FIG. 2 includes a primary regulator valve 201, a select valve 202, a line pressure modulator valve 203, a solenoid modulator valve 204, an SLP linear solenoid valve 205, an SLS linear solenoid valve 206, a transmission control valve 207, and a belt clamp. A pressure control valve 208 is provided.

  In the hydraulic control circuit 20 described above, the hydraulic pressure generated by the oil pump 7 is regulated by the primary regulator valve 201 to generate the line pressure PL. The primary regulator valve 201 is supplied with the control hydraulic pressure output from the SLS linear solenoid valve 206 via the select valve 202, and operates with the control hydraulic pressure as a pilot pressure. Then, the line pressure PL adjusted by the primary regulator valve 201 is supplied to the line pressure modulator valve 203, the transmission control valve 207, and the belt clamping pressure control valve 208.

  The line pressure modulator valve 203 is a pressure regulating valve that regulates the line pressure PL regulated by the primary regulator valve 201 to a constant hydraulic pressure (line pressure LPM2) lower than that. The line pressure LPM2 output from the line pressure modulator valve 203 is supplied to the SLP linear solenoid valve 205, the SLS linear solenoid valve 206, and the solenoid modulator valve 204.

  The solenoid modulator valve 204 is a pressure regulating valve that regulates the line pressure LPM2 regulated by the line pressure modulator valve 203 to a constant hydraulic pressure (modulator hydraulic pressure PSM) lower than that. The modulator hydraulic pressure PSM output from the solenoid modulator valve 204 is supplied to the transmission control valve 207 and the belt clamping pressure control valve 208.

  The SLP linear solenoid valve 205 and the SLS linear solenoid valve 206 are normally open type solenoid valves. The SLP linear solenoid valve 205 and the SLS linear solenoid valve 206 output a control hydraulic pressure (output hydraulic pressure) according to a current value determined by a duty signal (duty value) transmitted from the ECU 8. The control hydraulic pressure output from the SLP linear solenoid valve 205 is supplied to the shift control valve 207. The control hydraulic pressure output from the SLS linear solenoid valve 206 is supplied to the primary regulator valve 201 and the belt clamping pressure control valve 208.

  Note that the SLP linear solenoid valve 205 and the SLS linear solenoid valve 206 may be normally closed solenoid valves.

  Here, the shift control valve 207 and the belt clamping pressure control valve 208 will be described in detail.

(Shift control valve)
As shown in FIG. 2, a shift control valve 207 is connected to a hydraulic actuator (hereinafter also referred to as “primary hydraulic actuator”) 413 of the primary pulley 41 of the belt type continuously variable transmission 4.

  The transmission control valve 207 is provided with a spool 271 that is movable in the axial direction. A compression coil spring 272 is disposed in a compressed state on one end side (the lower end side in FIG. 2) of the spool 271 and a control hydraulic pressure port 273 is provided on one end side thereof. The SLP linear solenoid valve 205 described above is connected to the control hydraulic pressure port 273, and the control hydraulic pressure output from the SLP linear solenoid valve 205 is applied to the control hydraulic pressure port 273. Furthermore, the transmission control valve 207 is provided with an input port 274 to which the line pressure PL is supplied and an output port 275 connected (communication) to the hydraulic actuator 413 of the primary pulley 41.

  The transmission control valve 207 adjusts the line pressure PL using the control hydraulic pressure output from the SLP linear solenoid valve 205 as a pilot pressure, and supplies it to the hydraulic actuator 413 of the primary pulley 41. That is, the output hydraulic pressure (hereinafter also referred to as “primary sheave hydraulic pressure”) Pin of the shift control valve 207 controlled by the SLP linear solenoid valve 205 is supplied to the hydraulic actuator 413 of the primary pulley 41. Thereby, the hydraulic pressure supplied to the hydraulic actuator 413 of the primary pulley 41 is controlled, and the gear ratio γ of the belt-type continuously variable transmission 4 is controlled.

  Specifically, when the control hydraulic pressure output from the SLP linear solenoid valve 205 is increased from the state where a predetermined hydraulic pressure is supplied to the hydraulic actuator 413 of the primary pulley 41, the spool 271 moves upward in FIG. As a result, the output hydraulic pressure Pin of the shift control valve 207 increases, and the hydraulic pressure supplied to the hydraulic actuator 413 of the primary pulley 41 increases. As a result, the V-groove width of the primary pulley 41 becomes narrower and the speed ratio γ becomes smaller (upshift).

  On the other hand, when the control hydraulic pressure output from the SLP linear solenoid valve 205 decreases from the state in which a predetermined hydraulic pressure is supplied to the hydraulic actuator 413 of the primary pulley 41, the spool 271 moves downward in FIG. As a result, the output hydraulic pressure Pin of the transmission control valve 207 decreases, and the hydraulic pressure supplied to the hydraulic actuator 413 of the primary pulley 41 decreases. As a result, the V-groove width of the primary pulley 41 is increased and the transmission gear ratio γ is increased (downshift).

  In this case, for example, the target gear ratio is calculated from a preset shift map using the accelerator opening and the vehicle speed as parameters, and the actual gear ratio and the target gear ratio are set so that the actual gear ratio becomes the target gear ratio. The shift control of the belt type continuously variable transmission 4 is performed in accordance with the deviation. Specifically, by controlling the control oil pressure of the SLP linear solenoid valve 205, the oil pressure of the hydraulic actuator 413 of the primary pulley 41 of the belt type continuously variable transmission 4 is regulated and controlled, and the belt type continuously variable transmission 4 The gear ratio γ is continuously controlled.

(Belt clamping pressure control valve)
As shown in FIG. 2, a belt clamping pressure control valve 208 is connected to a hydraulic actuator (hereinafter also referred to as “secondary hydraulic actuator”) 423 of the secondary pulley 42 of the belt type continuously variable transmission 4.

  The belt clamping pressure control valve 208 is provided with a spool 281 that is movable in the axial direction. A compression coil spring 282 is disposed in a compressed state on one end side (the lower end side in FIG. 2) of the spool 281 and a control hydraulic pressure port 283 is provided on one end side thereof. The SLS linear solenoid valve 206 described above is connected to the control hydraulic pressure port 283, and the control hydraulic pressure output from the SLS linear solenoid valve 206 is applied to the control hydraulic pressure port 283. Further, the transmission control valve 207 is formed with an input port 284 to which the line pressure PL is supplied and an output port 285 connected (communication) to the hydraulic actuator 423 of the secondary pulley 42.

  The belt clamping pressure control valve 208 regulates the line pressure PL using the control hydraulic pressure output from the SLS linear solenoid valve 206 as a pilot pressure, and supplies it to the hydraulic actuator 423 of the secondary pulley 42. That is, the output hydraulic pressure (hereinafter also referred to as “secondary sheave hydraulic pressure”) Pd of the belt clamping pressure control valve 208 controlled by the SLS linear solenoid valve 206 is supplied to the hydraulic actuator 423 of the secondary pulley 42. As a result, the hydraulic pressure supplied to the hydraulic actuator 423 of the secondary pulley 42 is controlled, and the belt clamping pressure of the belt type continuously variable transmission 4 is controlled.

  Specifically, when the control hydraulic pressure output from the SLS linear solenoid valve 206 increases from a state in which a predetermined hydraulic pressure is supplied to the hydraulic actuator 423 of the secondary pulley 42, the spool 281 moves upward in FIG. As a result, the output hydraulic pressure Pd of the belt clamping pressure control valve 208 increases, and the hydraulic pressure supplied to the hydraulic actuator 423 of the secondary pulley 42 increases. As a result, the belt clamping pressure increases.

  On the other hand, when the control hydraulic pressure output from the SLS linear solenoid valve 206 decreases from the state in which the predetermined hydraulic pressure is supplied to the hydraulic actuator 423 of the secondary pulley 42, the spool 281 moves downward in FIG. As a result, the output hydraulic pressure Pd of the belt clamping pressure control valve 208 decreases, and the hydraulic pressure supplied to the hydraulic actuator 423 of the secondary pulley 42 decreases. As a result, the belt clamping pressure decreases.

  In this case, for example, the SLS linear is set according to a map of required oil pressure (corresponding to belt clamping pressure) set in advance so that belt slip does not occur with the accelerator opening corresponding to the transmission torque and the gear ratio γ as parameters. By controlling the control hydraulic pressure of the solenoid valve 206, the belt clamping pressure is controlled by adjusting the hydraulic pressure of the hydraulic actuator 423 (secondary sheave hydraulic pressure Pd) of the secondary pulley 42 of the belt type continuously variable transmission 4.

  As described above, in the shift control of the belt-type continuously variable transmission 4 that independently controls the primary sheave oil pressure Pin and the secondary sheave oil pressure Pd, the thrust ratio τ (τ = [secondary sheave oil pressure Pd × secondary side hydraulic cylinder). The primary sheave oil pressure Pin and the secondary sheave oil pressure Pd are controlled so as to be able to hold the pressure receiving area] / [primary sheave oil pressure Pin × primary side hydraulic cylinder pressure receiving area]). Specifically, the thrust ratio τ is calculated based on the speed ratio γ with reference to the thrust ratio map shown in FIG. 4, and the primary sheave oil pressure Pin and the secondary sheave oil pressure Pd are adjusted so as to balance with the calculated thrust ratio τ. I have control.

  Here, in the present embodiment, the line pressure PL regulated by the primary regulator valve 201 is an area where the speed ratio γ of the belt-type continuously variable transmission 4 is LOW (larger side) as shown in FIG. Then, in the region where the secondary sheave oil pressure Pd is higher by a predetermined margin and the speed ratio γ is high (smaller side), the control is performed so as to be higher than the primary sheave oil pressure Pin by a predetermined margin. By such control, it is possible to set the minimum necessary oil pressure at which the secondary sheave oil pressure Pd and the primary sheave oil pressure Pin can be obtained, and it is possible to prevent energy loss due to wasteful oil pressure output.

  The hydraulic control including the shift control of the belt type continuously variable transmission 4 and the line pressure PL control is performed by the hydraulic control circuit 20 and the ECU 8.

(ECU)
The ECU 8 includes a CPU 81, a ROM 82, a RAM 83, a backup RAM 84, and the like as shown in FIG.

  The ROM 82 stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU 81 executes arithmetic processing based on various control programs and maps stored in the ROM 82. The RAM 83 is a memory that temporarily stores the calculation results of the CPU 81 and data input from each sensor. The backup RAM 84 is a nonvolatile memory that stores data to be saved when the engine 1 is stopped. It is memory.

  The CPU 81, ROM 82, RAM 83, and backup RAM 84 are connected to each other via a bus 87 and are connected to an input interface 85 and an output interface 86.

  The input interface 85 includes an engine speed sensor 101, a throttle opening sensor 102, a water temperature sensor 103, a turbine speed sensor 104, a primary pulley speed sensor 105, a secondary pulley speed sensor 106, an accelerator position sensor 107, and a CVT oil. A temperature sensor 108, a hydraulic pressure sensor 109 for detecting the secondary sheave hydraulic pressure Pd, a lever position sensor 110 for detecting the lever position (operation position) of the shift lever 9, a sports mode switch 111, a brake pedal sensor 112, and a deceleration are detected. The front and rear G sensors 113 and the like are connected, and the output signals of the sensors, that is, the engine speed (engine speed) Ne, the throttle opening θth of the throttle valve 12, the cooling water temperature Tw of the engine 1, the turbine Rotational speed of turbine 27 (turbine rotational speed) Nt, primary pulley rotational speed (input shaft rotational speed) Nin, secondary pulley rotational speed (output shaft rotational speed) Nout, accelerator pedal operation amount (accelerator function) Acc, hydraulic control The oil temperature of the circuit 20 (CVT oil temperature Thc), the secondary sheave oil pressure Pd of the belt-type continuously variable transmission 4, the lever position (operation position) of the shift lever 9, the presence / absence of a sport mode request (ON / OFF), the brake pedal Signals representing the amount of depression, deceleration (front and rear G), and the like are supplied to the ECU 8.

  The output interface 86 is connected to the throttle motor 13, the fuel injection device 14, the ignition device 15, the hydraulic control circuit 20, and the like.

  Here, among the signals supplied to the ECU 8, the turbine rotational speed Nt coincides with the primary pulley rotational speed (input shaft rotational speed) Nin during forward travel in which the forward clutch C1 of the forward / reverse switching device 3 is engaged. The secondary pulley rotational speed (output shaft rotational speed) Nout corresponds to the vehicle speed V. The accelerator operation amount Acc represents the driver's requested output amount. The vehicle speed V may be detected by a vehicle speed sensor.

  The shift lever 9 includes a parking position “P” for parking, a reverse position “R” for reverse traveling, a neutral position “N” for interrupting power transmission, a drive position “D” for forward traveling, Further, during forward traveling, the gear ratio γ of the belt-type continuously variable transmission 4 is selectively operated to each position such as a manual position (sequential mode position) “M” where the manual operation can be increased or decreased.

  The manual position “M” includes a plurality of ranges in which a downshift position and an upshift position for increasing / decreasing the speed ratio γ, or a plurality of speed ranges in which the upper limit of the speed range (the side where the speed ratio γ is smaller) are different can be selected. Position etc. are provided.

  The lever position sensor 110 is, for example, a parking position “P”, a reverse position “R”, a neutral position “N”, a drive position “D”, a manual position “M”, an upshift position, a downshift position, or a range position. A plurality of ON / OFF switches for detecting that the shift lever 9 is operated are provided. In order to change the gear ratio γ manually, a downshift switch, an upshift switch, or a lever can be provided on the steering wheel or the like separately from the shift lever 9.

  The sport mode switch 111 selects a sport mode in which high running performance is obtained by shifting the shift line of the shift map during normal running to the high vehicle speed side.

  The ECU 8 controls the output of the engine 1, the gear ratio control and the belt clamping pressure control of the belt-type continuously variable transmission 4, and the engagement of the lock-up clutch 25 based on the output signals of the various sensors described above. The release control and the engagement / release control of the forward clutch C1 and the reverse brake B1 of the forward / reverse switching device 3 are executed.

  The output control of the engine 1 is executed by the throttle motor 13, the fuel injection device 14, the ignition device 15, the ECU 8, and the like.

<Belt clamping pressure control>
Here, the belt clamping pressure control executed by the ECU 8 will be described with reference to the flowchart shown in FIG. Note that the control routine of FIG. 6 is repeatedly executed by the ECU 8 at predetermined intervals (for example, several milliseconds to several tens of milliseconds).

  First, based on the output signal from the throttle opening sensor 101 or the accelerator opening sensor 107, the CPU 81 of the ECU 8 waits for the accelerator to be turned off while the vehicle is traveling normally (steps S1 and S2).

  When the accelerator is turned off during steady running, the CPU 81 of the ECU 8 changes the speed based on the output signals from the primary pulley rotation speed sensor 105 and the secondary pulley rotation speed sensor 106, that is, the primary pulley rotation speed Nin / secondary pulley rotation speed Nout. It is determined whether or not the ratio γ is shifted (shifted) to the LOW side (larger side) (step S3). When the gear ratio γ is not shifted to the LOW side, the CPU 81 of the ECU 8 returns the control to step S2. On the other hand, when the gear ratio γ is shifted to the LOW side, the CPU 81 of the ECU 8 advances the control to step S4.

  When the control proceeds to step S4, the CPU 81 of the ECU 8 sets the belt clamping pressure P to Pa (= P0 + Pup). Here, “P0” is the base belt clamping pressure (hydraulic pressure at which belt slip does not occur), and “Pup” is the belt clamping pressure to be increased during deceleration (hydraulic pressure γ, which is the LOW gear). It is set so small.) These P0 and Pup are obtained by referring to the P0 map shown in FIG. 7 and the Pup map shown in FIG. The P0 map and the Pup map are stored in the ROM 83 in the ECU 8.

  When the belt clamping pressure P is set to Pa, the CPU 81 of the ECU 8 detects whether the brake is turned on (whether the deceleration operation has been performed) based on the output signal from the brake pedal sensor 112 (step S5).

  When the brake ON is not detected, the CPU 81 of the ECU 8 determines whether or not the lock-up is OFF (step S6). When the lockup is OFF, the CPU 81 sets the belt clamping pressure P to the above P0, and returns the control to step S1. On the other hand, when the lockup is not OFF, the control is returned to step S1 without performing any control.

  On the other hand, when the brake ON is detected, the CPU 81 of the ECU 8 determines whether the deceleration is large (front / rear G ≦ −α) based on the output signal from the front / rear G sensor 113 (step 8). . If the deceleration is large (front and rear G ≦ −α), the CPU 81 sets the larger one of Pa and the hydraulic pressure Pbk (= P0 + ΔPbk) when the brake is ON as the belt clamping pressure P (step S9). Here, “ΔPbk” is a hydraulic pressure amount to be increased when the brake is ON. Thereafter, the CPU 81 returns the control to step S1. On the other hand, if the deceleration is small (front-back G> −α), the CPU 81 directly adopts Pa set in step S4 as the belt clamping pressure P (step S10). Thereafter, the CPU 81 returns the control to step S1.

<Action and effect>
According to the present embodiment, the following operations and effects are achieved.

  In the belt-type continuously variable transmission 4, when the vehicle is decelerated and stopped by the foot brake, the lockup OFF vehicle speed is pulled to a low speed. Therefore, the deceleration G changes just before the lockup is turned off, and an uncomfortable feeling due to the pull-in feeling occurs. At the time of deceleration stop, since the speed ratio γ of the belt type continuously variable transmission 4 is changed toward the maximum speed ratio γmax side, it is necessary to increase the belt clamping pressure (line pressure) as it stops. The feeling is promoted.

  For example, in the conventional control described in the above-mentioned Patent Document 2 and the like, as indicated by a dotted line in FIG. 9, the belt clamping pressure is increased and the speed ratio γ is large (LOW) during braking when the idle determination flag is switched from OFF to ON. The belt clamping pressure is increased as it changes to the side. When the belt clamping pressure is increased in this way, the friction torque increases, so the vehicle deceleration increases. However, when the above-described conventional control is performed, the deceleration (front-rear) G) becomes large and may give a sense of incongruity.

  On the other hand, in the present embodiment, as indicated by a solid line in FIG. 9, the belt clamping pressure is changed during a partial period T while the gear ratio γ is shifted to the larger side and the deceleration operation is detected. After increasing the size, gradually decrease. In other words, when deceleration is started with the brake on, a higher hydraulic pressure than the necessary belt clamping pressure is output within a range where the belt does not slip, and the belt clamping pressure is gradually lowered as the belt stops and the lockup is turned off from the lockup ON. The change of the front and rear G immediately before is eliminated. Accordingly, the change in the front-rear G (deceleration) is small as surrounded by an ellipse in FIG. As a result, the driver does not feel uncomfortable due to the pull-in.

  Further, in the present embodiment, the belt clamping pressure is increased immediately after detecting that the deceleration operation has been performed, and then decreased. Specifically, the belt clamping pressure while the deceleration operation is detected is set smaller as the speed ratio γ is larger. As a result, the deceleration change caused by the driver's deceleration operation and the deceleration change due to the change in the belt clamping pressure are performed almost simultaneously. Therefore, the driver does not feel a change in deceleration due to a change in belt clamping pressure.

  Further, in the present embodiment, so-called belt LOW return control is executed in which the speed ratio γ of the belt type continuously variable transmission 4 is changed toward the maximum speed ratio γmax when the brake is turned on. Under such control, when the deceleration after the brake is turned on is small (front-rear G> −α), Pa (set as the belt clamping pressure P when the gear ratio γ is shifted to the larger side (LOW side)). = P0 + Pup) is adopted as it is, so that the belt clamping pressure P changes along the Pa line L1, as shown in FIG. On the other hand, when the deceleration after the brake is ON (longitudinal G ≦ −α), the Pa is compared with the hydraulic pressure Pbk (= P0 + ΔPbk) when the brake is ON, and the larger hydraulic pressure is output. As shown in FIG. 10, P transitions along the Pa line L1 while the Pa line L1 exceeds the Pbk line L2, and then, at the point CP where the Pa line L1 and the Pbk line L2 cross each other. , The transition occurs along the Pbk line L2 exceeding the Pa line L1. Thereby, the feeling can be improved while ensuring the belt LOW return performance (basic performance).

  The present invention is not limited to the above embodiment.

  In the said embodiment, the example which applied this invention of the vehicle carrying a gasoline engine was described. However, the present invention is not limited to such a configuration. It can also be applied to vehicles equipped with other engines such as diesel engines. In addition to the engine (internal combustion engine), the vehicle power source may be an electric motor or a hybrid power source including both the engine and the electric motor.

  Moreover, in the said embodiment, the example which applied this invention to FF type vehicle was described. However, the present invention is not limited to such a configuration. The present invention can also be applied to FR (front engine / rear drive) type vehicles and four-wheel drive vehicles.

  In addition, it goes without saying that various design changes and modifications can be made within the scope of the claims attached to this specification.

102 throttle opening sensor 105 primary pulley rotation speed sensor 106 secondary pulley rotation speed sensor 107 accelerator opening sensor 112 brake pedal sensor 113 front and rear G sensor 4 belt type continuously variable transmission 41 primary pulley 42 secondary pulley 43 belt 8 ECU
81 CPU
82 ROM
83 RAM

Claims (3)

A vehicle control device including a belt-type continuously variable transmission having a pair of pulleys having variable groove widths and a belt wound around both pulleys,
A gear ratio determining means for determining whether or not the gear ratio is shifted to the larger side based on the rotation ratio of the two pulleys;
A deceleration operation detecting means for detecting whether or not a deceleration operation has been performed;
The gear ratio determining means determines that the gear ratio is shifted to a larger speed ratio and gradually increases the belt clamping pressure during a part of the period while the deceleration operation detecting means detects the deceleration operation. And a control means for reducing the size of the vehicle. A vehicle control device comprising a belt-type continuously variable transmission. In the control apparatus of the vehicle provided with the belt type continuously variable transmission according to claim 1,
The control means increases the belt clamping pressure immediately after detecting that the deceleration operation has been performed by the deceleration operation detection means, and then decreases the belt clamping pressure, for a vehicle equipped with a belt-type continuously variable transmission. Control device. In the control apparatus of the vehicle provided with the belt type continuously variable transmission according to claim 2,
The control means sets the belt clamping pressure while the speed reduction operation is detected by the speed reduction operation detecting means to be smaller as the gear ratio is larger. Control device.

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