JP2013181408A - Control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize an electric oil pump in a control device for a vehicle on which a continuously variable transmission capable of mechanically locking a primary pulley at the time of the maximum gear ratio is mounted and which can perform idle stop control.SOLUTION: A primary pulley of a continuously variable transmission is locked to the maximum gear ratio and idle stop control is performed (permitted) only when belt slip is suppressed by only supplying hydraulic pressure to a secondary pulley during engine restart. The idle stop control is not performed (electric oil pump stop) when it is necessary to supply hydraulic pressure to both the primary pulley and the secondary pulley. Such control eliminates the necessity for making the discharge flow rate of the electric oil pump secure the hydraulic pressure of both the primary pulley and the secondary pulley. Consequently, the electric oil pump can be miniaturized.

Description

  The present invention relates to a control device for a vehicle equipped with an engine and a continuously variable transmission.

  In a vehicle equipped with an engine (internal combustion engine), for the purpose of improving fuel consumption (fuel consumption rate) and reducing emissions, when a predetermined engine stop condition is satisfied, for example, when the vehicle stops waiting for an intersection signal In addition, idle stop control (eco-run control) is employed in which fuel supply to the combustion chamber of the engine is stopped (fuel cut) to stop the engine. Further, when a predetermined engine start condition is satisfied from this idle stop state (a state where the engine is stopped), cranking is performed by an electric motor such as a starter motor to restart the engine.

  Further, in a vehicle equipped with an engine, a belt-type continuously variable transmission (CVT) is used as a transmission that appropriately transmits torque and rotational speed generated by the engine to driving wheels in accordance with the traveling state of the vehicle. There is.

  A belt-type continuously variable transmission (hereinafter sometimes simply referred to as “continuously variable transmission”) is connected to a primary pulley (input pulley) to which driving force of an engine is transmitted and a drive wheel (output shaft). A secondary pulley (output pulley) and a belt wound around the primary pulley and the secondary pulley are provided. At the same time, the width of the pulley groove of one pulley is increased, and at the same time, the pulley groove of the other pulley is By narrowing the groove width, the belt winding radius (effective diameter) for each pulley is continuously changed to adjust the transmission ratio. Specifically, the primary pulley and the secondary pulley are each composed of a fixed sheave and a movable sheave, and the movable sheave is moved back and forth in the axial direction by a hydraulic actuator provided on the back side thereof, so that the transmission gear ratio is reduced to the minimum transmission gear ratio. The stepless adjustment is performed within the range of γmin (maximum speed gear ratio: maximum Hi) and maximum transmission ratio γmax (minimum speed gear ratio: maximum Low).

  Some continuously variable transmissions can mechanically lock the primary pulley at the maximum gear ratio γmax. For example, at the maximum gear ratio γmax, the primary sheave (movable sheave) is mechanically moved when the movable sheave of the primary pulley hits the wall on the case side and further movement (movement toward the opening side of the movable sheave) is restricted. There is a continuously variable transmission that locks to (see, for example, Patent Document 1). In the continuously variable transmission with such a configuration, the movable sheave of the primary pulley hits the wall on the case side at the maximum gear ratio γmax (because movement to the opening side of the movable sheave is restricted) The groove width of the primary pulley can be held (locked) by the reaction force (belt tension). As a result, when the gear ratio of the continuously variable transmission is in the maximum gear ratio γmax state, it is not necessary to secure the hydraulic pressure of the primary pulley, and the hydraulic pressure is reduced by that amount (the amount by which the primary pulley can be mechanically locked). can do. That is, in the maximum gear ratio γmax state, only the hydraulic pressure on the secondary pulley side needs to be secured.

  As a technique related to control of a vehicle equipped with a continuously variable transmission (eco-run vehicle), when the transmission ratio of the continuously variable transmission is on the Hi side (side where the transmission ratio is smaller) than a predetermined value, A technique for prohibiting automatic stop has been proposed (see, for example, Patent Document 2).

JP 2010-053879 A JP 2000-328980 A JP-A-11-132321

  A vehicle that can execute idle stop control (eco-run vehicle) includes an electric oil pump that supplies hydraulic pressure when the engine is stopped (see, for example, Patent Document 2). The electric oil pump becomes larger as the required discharge flow rate increases, and the cost increases, so a reduction in the discharge flow rate is required.

  On the other hand, in an eco-run vehicle equipped with a continuously variable transmission, the speed ratio of the continuously variable transmission is the maximum speed ratio when the vehicle is stopped due to sudden deceleration or other factors (for example, at high oil temperature). There is a case where it does not return to γmax. If the vehicle does not return to the maximum gear ratio γmax when the vehicle is stopped, it is necessary to supply hydraulic pressure to both the primary pulley and the secondary pulley to prevent belt slippage, and there is a problem that it is difficult to reduce the size of the electric oil pump.

  The present invention has been made in consideration of such circumstances, and is equipped with a continuously variable transmission capable of mechanically locking a primary pulley at the maximum gear ratio and capable of executing idle stop control. An object of the present invention is to realize a control capable of reducing the size of an electric oil pump in a vehicle control device.

  The present invention includes an engine, a primary pulley to which power of the engine is input, a secondary pulley, and a belt wound around the primary pulley and the secondary pulley, and the primary gear is at a maximum gear ratio. A continuously variable transmission capable of mechanically locking the pulley and an electric oil pump that supplies hydraulic pressure to the secondary pulley when the engine is stopped are mounted, and when a preset condition is satisfied It is premised on a vehicle control device capable of executing idle stop control for automatically stopping the engine. In such a vehicle control device, as one of the preset conditions, a condition that a speed ratio of the continuously variable transmission is a maximum speed ratio (lowest) is included. Characteristic.

  According to the present invention, the idle stop control is executed to automatically stop the engine when a condition (idle stop condition) including that the speed ratio of the continuously variable transmission is the maximum speed ratio (lowest) is satisfied. In other words, idle stop control is executed (permitted) only when the primary pulley of the continuously variable transmission is locked to the maximum gear ratio and belt slippage can be suppressed during engine restart by supplying hydraulic pressure only to the secondary pulley. When it is necessary to supply hydraulic pressure to both the primary pulley and the secondary pulley, idle stop control is not executed (electric oil pump stop). Such control eliminates the need for the discharge flow rate of the electric oil pump to be a flow rate that can ensure the hydraulic pressures of both the primary pulley and the secondary pulley, and thus enables the electric oil pump to be downsized.

  According to the present invention, the idle stop control is performed only when the speed ratio of the continuously variable transmission is the maximum speed ratio and the belt slip can be suppressed when the engine is restarted only by supplying the hydraulic pressure only to the secondary pulley. Therefore, the electric oil pump can be downsized.

It is a schematic structure figure showing an example of a vehicle to which the present invention is applied. It is sectional drawing which shows the structure of the primary pulley of a belt-type continuously variable transmission, and its peripheral part. It is a circuit block diagram of the hydraulic control circuit 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 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 block diagram which shows the structure of control systems, such as ECU. It is a flowchart which shows an example of the control at the time of a vehicle stop. It is a timing chart which shows an example of control at the time of a vehicle stop.

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

  FIG. 1 is a schematic configuration diagram of a vehicle to which the present invention is applied.

  The vehicle 100 in this example is an FF (front engine / front drive) type vehicle, and is an engine (internal combustion engine) 1 that is a driving power source, a torque converter 2 as a fluid transmission device, a forward / reverse switching device 3, a belt. A continuously variable transmission (CVT) 4, a reduction gear device 5, a differential gear device 6, and an ECU (Electronic Control Unit) 300 are mounted.

  A crankshaft 11, which 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 through the forward / reverse switching device 3, the belt type continuously variable transmission 4, and the reduction gear device 5. Are transmitted to the differential gear device 6 and distributed to the left and right drive wheels 7.

  The engine 1, torque converter 2, forward / reverse switching device 3, belt type continuously variable transmission 4, hydraulic control circuit 20, and ECU 300 will be described below.

-Engine-
The engine 1 is a multi-cylinder gasoline engine, for example. 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 300. Specifically, the optimum intake air amount (in accordance with 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 as to obtain a target intake air amount. 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 exhibits 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 (engage 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 8 that is connected to and driven by the pump impeller 21.

  Further, in this embodiment, as shown in FIG. 3, an electric oil pump 80 that is driven by an electric motor 81 to generate hydraulic pressure is provided in parallel with the mechanical oil pump 8 (driven by the engine 1). When the engine 1 is stopped and the mechanical oil pump 8 does not generate hydraulic pressure, the electric oil pump 80 generates hydraulic pressure. The discharge flow rate of the electric oil pump 80 is, as will be described later, when the gear shift γ of the belt-type continuously variable transmission 4 is the maximum gear ratio γmax (when the primary pulley 41 is locked to the maximum gear ratio γmax). The flow rate is such that the hydraulic pressure of the secondary pulley 42 can be secured.

-Forward / reverse 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 via the reverse brake B1.

  The forward clutch C1 and the reverse brake B1 are hydraulic friction engagement elements that are engaged and released by a hydraulic control circuit 20 to be described later. The forward clutch C1 is engaged and the reverse brake B1 is released. Thus, the forward / reverse switching device 3 is integrally rotated to establish (achieve) 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 (achieves) a reverse power transmission path. In this state, the input shaft 40 rotates in the reverse direction with respect to the turbine shaft 28, 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 becomes neutral (interrupted state) for interrupting 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, a metal belt 43 wound between the primary pulley 41 and the secondary pulley 42, and the like. Yes.

  A primary pulley rotation speed sensor 105 is disposed in the vicinity of the primary pulley 41. From the output signal of the primary pulley rotation speed sensor 105, the input shaft rotation speed Nin of the belt type continuously variable transmission 4 can be calculated. Further, a secondary pulley rotation speed sensor 106 is disposed in the vicinity of the secondary pulley 42. From the output signal of the secondary pulley rotation speed sensor 106, the output shaft rotation speed Nout of the belt type continuously variable transmission 4 can be calculated. Further, the vehicle speed spd can be calculated based on the output signal of the secondary pulley rotation speed sensor 106. The primary pulley rotation speed sensor 105 and the secondary pulley rotation speed sensor 106 are both electromagnetic pickup type rotation speed sensors.

  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, the secondary pulley 42 is a variable pulley whose effective diameter is variable, and is a fixed sheave 421 fixed to the output shaft 44 and a movable sheave arranged on the output shaft 44 so as to be slidable only in the axial direction. 422.

  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 300 and the hydraulic control circuit 20.

<Specific configuration around the primary pulley>
Next, a specific configuration of the primary pulley 41 and its peripheral part in the belt type continuously variable transmission 4 will be described with reference to FIG. The upper half of FIG. 2 shows a state where the winding radius of the belt 43 around the primary pulley 41 is reduced (maximum speed ratio γmax), and the lower half shows a larger winding radius of the belt 43 around the primary pulley 41. (The state of the minimum gear ratio γmin).

  As described above, the primary pulley 41 includes the fixed sheave 411 integrally formed with the input shaft 40 and the movable sheave 412 disposed so as to be movable forward and backward with respect to the fixed sheave 411. The input shaft 40 is rotatably supported by the transmission case 400 via two bearings 61 and 62.

  The movable sheave 412 has an inner cylindrical portion 412a that slides along the outer peripheral surface of the input shaft 40, and a radius that is continuously formed from the end portion (end portion on the fixed sheave 411 side) of the inner cylindrical portion 412a toward the outer peripheral side. It has a direction part 412b and a substantially cylindrical outer cylinder part 412c formed continuously at the outer peripheral end of the radial direction part 412b and extending in the direction opposite to the side where the fixed sheave 411 is disposed.

  A cylinder member 50 constituting a hydraulic actuator 413 is disposed on the back side of the movable sheave 412. The cylinder member 50 has an inner radial direction portion 51 constituting an inner peripheral portion thereof, and is directed to the outer side so as to be continuous with the inner radial direction portion 51 and to face the back surface of the radial direction portion 412b of the movable sheave 412. The outer radial direction part 52 extended and the cylindrical part 53 continuously formed on the outer peripheral side of the outer radial direction part 52 and positioned on the outer peripheral side of the outer cylindrical part 412c of the movable sheave 412. .

  A step 40 a is formed in the vicinity of the tip of the input shaft 40, and the inner radial direction portion 51 of the cylinder member 50 is connected to the input shaft via the step 40 a and the inner race of the bearing 62. It is fixed to the input shaft 40 by a lock nut 63 that is fastened to the outer periphery of the 40.

  The position near the tip of the outer cylindrical portion 412c of the movable sheave 412 is in contact with the inner surface of the cylindrical portion 53 of the cylinder member 50 via the seal ring 412d, and between the seal ring 412d and the inner surface of the cylindrical portion 53. A sealing surface is formed. As a result, a control hydraulic chamber 54 constituting the hydraulic actuator 413 of the primary pulley 41 is formed by a space surrounded by the movable sheave 412 and the cylinder member 50, and the hydraulic pressure of the control hydraulic chamber 54 is controlled (amount of supplied oil). ), The moving position of the movable sheave 412 relative to the fixed sheave 411 is changed.

  In the primary pulley 41 of this example, the tip 412e (the end opposite to the fixed sheave 411) of the inner cylindrical portion 412a of the movable sheave 412 is the cylinder member when the maximum gear ratio γmax is in the state. 50, the inner radial direction 51 (corresponding to the wall on the case side; hereinafter referred to as “lock wall 51”), and further movement (to the side where the movable sheave 412 opens (the side away from the fixed sheave 411)) (See the upper half of FIG. 2). In this state, the reaction force from the secondary pulley 42 (belt tension generated by the clamping pressure) acts, so that the movable sheave 412 is in contact with the lock wall 51. That is, the primary pulley 41 (movable sheave 412) is mechanically locked when the speed ratio of the belt type continuously variable transmission 4 is in the maximum speed ratio γmax state.

-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. 3 includes a primary regulator valve 201, a select valve 202, a line pressure modulator valve 203, a solenoid modulator valve 204, a linear solenoid valve (SLP) 205, a linear solenoid valve (SLS) 206, and a shift control valve 207. , And a belt clamping pressure control valve 208 and the like.

  The hydraulic control circuit 20 uses a mechanical oil pump 8 using the engine 1 as a driving force source and an electric oil pump 80 using the electric motor 81 as a driving force source as hydraulic sources. The mechanical oil pump 8 and the electric oil pump 80 are connected in parallel.

  In the hydraulic control circuit 20 of this example, the hydraulic pressure generated by the mechanical oil pump 8 (the electric oil pump 80 when the engine is stopped) 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 linear solenoid valve (SLS) 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 linear solenoid valve (SLP) 205, the linear solenoid valve (SLS) 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 linear solenoid valve (SLP) 205 and the linear solenoid valve (SLS) 206 are normally open type solenoid valves. The linear solenoid valve (SLP) 205 and the linear solenoid valve (SLS) 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 300. The control hydraulic pressure output from the linear solenoid valve (SLP) 205 is supplied to the shift control valve 207. The control hydraulic pressure output from the linear solenoid valve (SLS) 206 is supplied to the primary regulator valve 201 and the belt clamping pressure control valve 208.

  The linear solenoid valve (SLP) 205 and the linear solenoid valve (SLS) 206 may be normally closed solenoid valves.

  Next, the transmission control valve 207 and the belt clamping pressure control valve 208 will be described.

-Shift control valve-
As shown in FIG. 3, a shift control valve 207 is connected to a hydraulic actuator 413 (hereinafter also referred to as a primary side 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. 3) of the spool 271 and a control hydraulic pressure port 273 is provided on one end side thereof. The control hydraulic pressure port 273 is connected to the linear solenoid valve (SLP) 205 described above, and the control hydraulic pressure output from the linear solenoid valve (SLP) 205 is applied to the control hydraulic pressure port 273. Further, 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 shift control valve 207 regulates the line pressure PL using the control hydraulic pressure output from the linear solenoid valve (SLP) 205 as a pilot pressure, and supplies it to the hydraulic actuator 413 of the primary pulley 41. That is, the output oil pressure Pin (hereinafter also referred to as primary sheave oil pressure Pin) of the shift control valve 207 controlled by the linear solenoid valve (SLP) 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 a predetermined hydraulic pressure is supplied to the hydraulic actuator 413 of the primary pulley 41 and the control hydraulic pressure output from the linear solenoid valve (SLP) 205 increases, 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 linear solenoid valve (SLP) 205 decreases from the state where 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 Acc and the vehicle speed spd as parameters, and the actual gear ratio and the target gear shift are set so that the actual gear ratio becomes the target gear ratio. Shift control of the belt type continuously variable transmission 4 is performed according to the deviation from the ratio. Specifically, by controlling the control hydraulic pressure of the linear solenoid valve (SLP) 205, the hydraulic pressure of the hydraulic actuator 413 of the primary pulley 41 of the belt type continuously variable transmission 4 is regulated and controlled. The gear ratio γ of the machine 4 is continuously controlled.

-Belt clamping pressure control valve-
As shown in FIG. 3, a belt clamping pressure control valve 208 is connected to a hydraulic actuator 423 (hereinafter also referred to as a 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 arranged in a compressed state on one end side (the lower end side in FIG. 3) of the spool 281 and a control hydraulic pressure port 283 is provided on one end side thereof. The control hydraulic pressure port 283 is connected to the linear solenoid valve (SLS) 206 described above, and the control hydraulic pressure output from the linear solenoid valve (SLS) 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 linear solenoid valve (SLS) 206 as a pilot pressure, and supplies it to the hydraulic actuator 423 of the secondary pulley 42. That is, the output hydraulic pressure Pd (hereinafter also referred to as secondary sheave hydraulic pressure Pd) of the belt clamping pressure control valve 208 controlled by the linear solenoid valve (SLS) 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 linear solenoid valve (SLS) 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 linear solenoid valve (SLS) 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, a linear solenoid valve according to a map of necessary hydraulic pressure (corresponding to belt clamping pressure) set in advance so that belt slip does not occur with the accelerator opening Acc and the gear ratio γ corresponding to the transmission torque as parameters. By controlling the control hydraulic pressure of (SLS) 206, 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 is controlled to control the belt clamping pressure.

  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.

  In this example, the line pressure PL regulated by the primary regulator valve 201 is, as shown in FIG. 5, the secondary sheave hydraulic pressure in the region where the speed ratio γ of the belt type continuously variable transmission 4 is low (larger). In a region where the gear ratio γ is higher than the Pd by a predetermined margin and the gear ratio γ is high (smaller), the primary sheave oil pressure Pin is controlled to be higher by a predetermined margin. By such control, it is possible to set the minimum necessary hydraulic pressure at which the secondary sheave hydraulic pressure Pd and the primary sheave hydraulic pressure Pin can be obtained, and it is possible to prevent energy loss due to wasteful hydraulic 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 300.

-ECU-
As shown in FIG. 6, the ECU 300 includes a CPU (Central Processing Unit) 301, a ROM (Read Only Memory) 302, a RAM (Random Access Memory) 303, a backup RAM 304, and the like.

  The ROM 302 stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU 301 executes arithmetic processing based on various control programs and maps stored in the ROM 302. A RAM 303 is a memory for temporarily storing calculation results in the CPU 301 and data input from each sensor. A backup RAM 304 is a non-volatile memory for storing data to be saved when the engine 1 is stopped. is there.

  The CPU 301, ROM 302, RAM 303, and backup RAM 304 are connected to each other via a bus 307, and are connected to an input interface 305 and an output interface 306.

  The input interface 305 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, a brake pedal. The brake pedal sensor 108 for detecting the operation amount (brake pedaling force), the hydraulic sensor 109 for detecting the secondary sheave oil pressure Pd, the lever position sensor 110 for detecting the lever position (operation position) of the shift lever 9, and the like are connected. The output signals of the sensors, that is, the rotation speed Ne of the engine 1 (engine rotation speed) Ne, the throttle opening θth of the throttle valve 12, the cooling water temperature Tw of the engine 1, the rotation speed of the turbine shaft 28 (turbine rotation speed) Nt, Primary pulley rotation speed (input shaft rotation speed) Nin, secondary pulley rotation speed (output shaft rotation speed) Nout, accelerator pedal operation amount (accelerator function) Acc, brake pedal operation amount (brake pedaling force), belt-type continuously variable transmission Signals representing the secondary sheave hydraulic pressure Pd of the machine 4 and the lever position (operation position) of the shift lever 9 are supplied to the ECU 300. In addition, an ignition switch 120 is connected to the input interface 305, and an IG-ON signal or an IG-OFF signal from the ignition switch 120 is supplied to the ECU 300.

  Connected to the output interface 306 are the throttle motor 13, the fuel injection device 14, the ignition device 15, the hydraulic control circuit 20, the electric motor 81 of the electric oil pump 80, and the like.

  Here, among the signals supplied to the ECU 300, the turbine rotational speed Nt coincides with the primary pulley rotational speed (input shaft rotational speed) Nin during forward travel where the forward clutch C1 of the forward / reverse switching device 3 is engaged. The secondary pulley rotation speed (output shaft rotation speed) Nout corresponds to the vehicle speed spd. The accelerator operation amount Acc represents the driver's requested output amount. A vehicle speed sensor that detects the vehicle speed spd may be provided.

  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, During forward running, the gear ratio γ of the belt type continuously variable transmission 4 is selectively operated to each position such as a manual position “M” where the manual operation can increase or decrease the speed ratio γ.

  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 of the belt type continuously variable transmission 4 by manual operation, 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 ECU 300 controls the output of the engine 1, the transmission ratio control and the belt clamping pressure control of the belt-type continuously variable transmission 4, and the lock-up clutch 25 based on the output signals of the various sensors described above. Engagement / release control is executed.

  Furthermore, the ECU 300 executes [idle stop control] and [control when the vehicle stops], which will be described later. Note that “when the vehicle is stopped” includes immediately before the vehicle is stopped.

  Here, 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 300, and the like. Further, as the control of the engine 1, the ECU 300 controls the intake air amount (the opening degree of the throttle valve 12) so that the actual engine speed Ne calculated from the output signal of the engine speed sensor 101 becomes the target idle speed. Idle rotation speed control for feedback control is executed.

  Further, as one control of the belt-type continuously variable transmission 4, for example, the ECU 300 monitors the vehicle speed based on the output signal of the secondary pulley rotation speed sensor 106, and the vehicle speed spd is a predetermined first determination during vehicle deceleration. When the threshold Thspd1 is lowered (for example, 10 km / h) (when spd ≦ Thspd1), control is performed to change the gear ratio of the belt-type continuously variable transmission 4 toward the maximum gear ratio γmax.

  The vehicle control device of the present invention is realized by the program executed by the ECU 300 described above.

[Idle stop control]
The ECU 300 automatically stops the engine 1 when an idle stop condition (engine automatic stop condition) is satisfied, and automatically starts the engine 1 when an idle stop release condition (engine automatic start condition) is satisfied. It is possible to execute so-called idle stop control (eco-run control).

  Examples of the idle stop condition include that the ignition switch 120 is on (IG-ON), the accelerator is off (recognized from the output signal of the accelerator opening sensor 107), and the brake pedal force (the output of the brake pedal sensor 108). (Recognized from the signal) is equal to or greater than a predetermined determination threshold value, and includes a vehicle stop state (vehicle speed spd is 0). Furthermore, in the present embodiment, the condition that the speed ratio γ of the belt-type continuously variable transmission 4 is the maximum speed ratio (lowest) γmax when the vehicle is stopped is also included in one of the idle stop conditions. When such an idle stop condition is satisfied, the ECU 300 issues a command to the fuel injection device 14 to automatically stop the engine 1 by stopping the fuel injection (fuel cut). In addition to fuel cut, ignition cut may be performed.

  On the other hand, as the idle stop release condition, for example, after the idle stop condition is satisfied, for example, the pedal effort of the brake pedal is relaxed, and the brake pedal effort (recognized from the output signal of the brake pedal sensor 108) is greater than a predetermined determination threshold. On condition that it has become smaller. When the idle stop cancellation condition is satisfied when the engine 1 is automatically stopped (idle stop state), the ECU 300 issues a command to the fuel injection device 14 and a starter motor (not shown) to start fuel injection. Then, the starter motor is operated to crank the engine 1 and the engine 1 is automatically restarted.

[Control when the vehicle is stopped]
Next, an example of the control performed by the ECU 300 when the vehicle is stopped (including immediately before the stop) will be described with reference to the flowchart of FIG. 7 and the timing chart of FIG. The control routine of FIG. 7 is repeatedly executed in ECU 300.

  When the control routine of FIG. 7 is started, first, in step ST101, it is determined whether or not the vehicle is decelerating based on the vehicle speed spd calculated from the output signal of the secondary pulley rotation speed sensor 106. If the determination result is negative (NO), the process returns. If the determination result of step ST101 is affirmative (YES), the process proceeds to step ST102.

  In step ST102, it is determined whether or not the vehicle speed spd calculated from the output signal of the secondary pulley rotation speed sensor 106 is equal to or lower than a predetermined first determination threshold Thspd1. If the determination result is negative (NO), the process returns. When the determination result of step ST102 is affirmative (YES) (when [vehicle speed spd ≦ Thspd1]), the process proceeds to step ST103.

  The first determination threshold Thspd1 used in the determination process of step ST102 starts the above-described speed change control during deceleration (control for changing the speed ratio of the belt type continuously variable transmission 4 toward the maximum speed ratio γmax). The vehicle speed (for example, 10 km / h).

  In step ST103, a maximum gear ratio γmax determination (maximum Low determination) is performed. Specifically, the amount of movement of the movable sheave 412 of the primary pulley 41 per unit time is sequentially calculated based on the primary sheave oil pressure Pin and the secondary sheave oil pressure Pd from the time when the above step ST102 is affirmative (YES). Then, the gear ratio γ of the belt type continuously variable transmission 4 is estimated based on the moving amount of the movable sheave 412. Then, it is determined whether or not the estimated speed ratio has reached the maximum speed ratio γmax before the vehicle speed spd decreases to the predetermined second determination threshold Thspd2, and the estimated speed ratio reaches the maximum speed ratio γmax. If it is determined (indicated by the solid line in FIG. 8), “γmax determination ON” is determined. On the other hand, the estimated speed ratio becomes the maximum speed ratio γmax until the vehicle speed spd decreases to the predetermined second determination threshold Thspd2. If not reached (indicated by a broken line in FIG. 8), it is determined that “γmax determination is OFF”.

  The second determination threshold value Thspd2 is based on the lower limit value of the value (vehicle speed spd) with which the secondary pulley rotational speed sensor 106 can accurately detect the rotational speed (output shaft rotational speed) Nout of the secondary pulley 42. The set value (for example, 3 km / h) is used.

  Next, in step ST104, it is determined whether or not the above-described idle stop condition is satisfied. Specifically, (j1) the ignition switch 120 is on (IG-ON), (j2) the accelerator is off (recognized from the output signal of the accelerator opening sensor 107), (j3) the brake pedal force (brake In addition to the condition that (recognized from the output signal of the pedal sensor 108) is equal to or greater than a predetermined determination threshold and (j4) the vehicle is in a stopped state (the vehicle speed spd is 0), the determination result in the step ST103 is “ If the condition that “γmax determination is ON” is satisfied, it is determined that the idle stop condition is satisfied, and the process proceeds to step ST105.

  On the other hand, when any one of the conditions (j1) to (j4) is not satisfied and when all the conditions (j1) to (j4) are satisfied, However, if the determination result in step ST103 is “γmax determination OFF”, it is determined that the idle stop condition is not satisfied, and the process proceeds to step ST110.

  In step ST105, the idle stop control is permitted and the engine 1 is automatically stopped. When the operation of the engine 1 is stopped, the electric oil pump 80 is driven to ensure the hydraulic pressure of the secondary pulley 42 of the belt type continuously variable transmission 4. Thereafter, when the above-described idle stop cancellation condition (the brake pedal force is equal to or less than the predetermined determination threshold) is satisfied, the stopped engine 1 is restarted (automatically started), for example, the hydraulic pressure by the mechanical oil pump 8 rises. Then, the driving of the electric oil pump 80 is stopped.

  On the other hand, if the determination result in step ST104 is negative (NO) (when the idle stop condition is not satisfied), the idle stop prohibition flag is turned ON in step ST110 (the state of the broken line in FIG. 8), and the idle Stop control is prohibited. When the idle stop control is prohibited, the electric oil pump 80 remains stopped.

  Thereafter, in step ST111, it is determined whether an idle stop prohibition reset condition is satisfied. Specifically, for example, it is determined whether or not the current gear ratio γ of the belt-type continuously variable transmission 4 has reached the maximum gear ratio γmax (determines whether or not [γmax determination ON] has been reached), and the determination. If the result is affirmative (YES), the idle stop prohibition flag is turned OFF (for example, timing ta in FIG. 8), and idle stop control is permitted (step ST105). On the other hand, if the determination result in step ST111 is negative (NO), prohibition of idle stop control is continued.

<Effect>
As described above, according to the control of this example, the primary pulley 41 of the belt type continuously variable transmission 4 is locked to the maximum gear ratio γmax ([γmax determination ON]), and only the secondary pulley 42 is used. The idle stop control is permitted (executed) only when the belt slip can be suppressed when the engine 1 is restarted only by supplying the hydraulic pressure, and the hydraulic pressure needs to be supplied to both the primary pulley 41 and the secondary pulley 42 ( When [γmax determination is OFF], the idle stop control is not executed (the electric oil pump 80 is stopped). Such control eliminates the need for the discharge flow rate of the electric oil pump 80 to be a flow rate that can ensure the hydraulic pressures of both the primary pulley 41 and the secondary pulley 42. As a result, the electric oil pump 80 can be reduced in size.

-Other embodiments-
In the above example, the present invention is applied to a continuously variable transmission control device for a vehicle equipped with a gasoline engine. However, the present invention is not limited to this, and other engines such as a diesel engine are mounted. The present invention can also be applied to a control device for a continuously variable transmission of a vehicle. 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.

  The present invention is not limited to FF (front engine / front drive) type vehicles, but can be applied to FR (front engine / rear drive) type vehicles and four-wheel drive vehicles.

  INDUSTRIAL APPLICABILITY The present invention can be used in a control device for a vehicle on which an engine and a continuously variable transmission are mounted. More specifically, the continuously variable transmission capable of mechanically locking a primary pulley at the maximum gear ratio is mounted. The present invention can be effectively used for a vehicle control device.

DESCRIPTION OF SYMBOLS 1 Engine 4 Belt type continuously variable transmission mechanism 8 Mechanical oil pump 20 Hydraulic control circuit 41 Primary sheave 412 Movable sheave 413 Hydraulic actuator 42 Secondary pulley 423 Hydraulic actuator 43 Belt 80 Electric oil pump 105 Primary pulley rotation speed sensor 106 Secondary pulley rotation speed Sensor 107 Accelerator opening sensor 108 Brake pedal sensor 120 Ignition switch ECU 300

Claims (1)

Engine,
It has a primary pulley to which the engine power is input, a secondary pulley, and a belt wound around the primary pulley and the secondary pulley, and mechanically locks the primary pulley at the maximum gear ratio. A continuously variable transmission capable of
An electric oil pump for supplying hydraulic pressure to the secondary pulley when the engine is stopped;
Is installed,
A vehicle control apparatus capable of executing idle stop control for automatically stopping the engine when a preset condition is satisfied,
One of the preset conditions includes a condition that the gear ratio of the continuously variable transmission is a maximum gear ratio.

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