JP2011133012A - Starting clutch control device of idle stop vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a start clutch control device of an idle stop vehicle which can constrain belt slip when switching to a traveling range takes place immediately after transition to idle stop in a non-traveling range. <P>SOLUTION: It is decided whether or not or a state in which an engine speed is constant value Ne or more and a belt interposed pressure is constant value Pb or more continues over a constant time ΔT or more at the time of switching from N to D in idle stop state and if the decision is positive, a starting clutch is engaged in usual engagement pattern and if the decision is negative, it is engaged in pattern which controls a clutch pressure of the starting clutch so that the clutch transmission torque of the starting clutch does not exceed a belt transmission torque. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a starting clutch control device for an idle stop vehicle, and more particularly to a starting clutch control device when starting from an idle stop state.

2. Description of the Related Art Conventionally, an idle stop vehicle is known in which an engine is automatically stopped when the vehicle is stopped to suppress wasteful fuel consumption and emission of exhaust gas while the vehicle is stopped. Engine stop conditions in such an idle stop vehicle include vehicle stop and brake ON, and engine restart conditions (return conditions) include brake OFF and accelerator pedal depression.

In the idling stop vehicle as described above, an oil pump driven by the engine, a belt-type continuously variable transmission whose output shaft is connected to a drive wheel, and a starting clutch provided between the engine and the continuously variable transmission And a hydraulic control device that supplies hydraulic pressure to the continuously variable transmission and the starting clutch based on the hydraulic pressure generated by the oil pump. In such a vehicle, the oil pump is also stopped along with the idle stop, so that the hydraulic pressure supplied to the continuously variable transmission and the start clutch is lost during the idle stop. The idle stop is performed not only in the travel range such as D but also in the non-travel range such as the N range. In such an N (non-running) range idle stop state, when a return condition such as brake OFF is satisfied, the idle stop return (engine restart) is performed. However, if the shift lever is switched from the N range to the D range when the engine speed immediately after returning from idle stop is low, the clutch pressure may rise earlier than the belt clamping pressure, and belt slipping or shock may occur.

FIG. 7 shows the engine speed, belt clamping pressure, when the idle stop return command is issued at time t10 during idle stop in the N range, and the shift position is switched from the N range to the D range at time t11. The time change of clutch pressure is shown. At time t11, the engine speed is lower than the idle speed, and the belt clamping pressure is also low. At time t12, the engine speed increases and the belt clamping pressure also increases with a delay. On the other hand, the initial pressure (for example, the hydraulic pressure corresponding to the return spring force of the piston in the starting clutch) is initially supplied to the starting clutch, as in the normal (from engine driving) N → D switching. When the supply of pressure is completed, pressure increase control (sweep control) is performed with a certain time gradient from the initial pressure, and then the starting clutch is completely engaged.

However, the engine speed does not increase to the idle speed immediately after the idle stop return command is issued, but there is a certain time delay. In addition, at the beginning of idle stop return, the discharge pressure of the oil pump is low as the engine speed is low, and it takes time to fill the hydraulic oil in the pulley oil chamber of the continuously variable transmission, and the belt clamping pressure (belt transmission torque) The rise is also delayed. On the other hand, a clutch pressure having an initial pressure as a target value is supplied to the starting clutch, but the actual clutch pressure does not immediately rise to a hydraulic pressure corresponding to the initial pressure. As described above, due to the delay in the increase in the engine speed and the hydraulic pressure in each part, the clutch transmission torque of the starting clutch may exceed the belt transmission torque of the continuously variable transmission due to the switching timing from the N to D range. And shocks occurred.

In Patent Literature 1, when the shift position is switched from the non-traveling range to the traveling range, it is determined whether or not the engine has been automatically stopped, and when the engine has been automatically stopped or not. And changing the method of rapid pressure increase control in the initial stage of oil supply. In Patent Document 2, when the shift operation from the non-traveling range to the traveling range is performed after the engine is restarted, the mode of rapid pressure increase control of the starting clutch is changed according to the degree of rising of the hydraulic pressure or the elapsed time from the engine restart. Is disclosed.

Patent Document 1 is a rapid pressure increase control in a case where the engine is restarted by performing a shift operation from the non-traveling range to the traveling range, and is switched to the traveling range after the engine restart is started in the non-traveling range. In this case, only the same control as the normal clutch control is performed, and the problem of belt slip cannot be solved. In Patent Document 2, the clutch engagement control can be optimized in the shift operation after the engine restart, but since the degree of increase in the engine speed after the engine restart varies, Even if the rapid pressure increase control of the starting clutch is changed only by the elapsed time, it is not always possible to eliminate belt slip and shock. In particular, Patent Document 2 is directed to a multi-plate clutch type automatic transmission, and does not consider the correlation between the belt transmission torque of the continuously variable transmission and the clutch transmission torque of the starting clutch, thereby suppressing belt slip. It is difficult.

JP-A-11-351371 JP 2000-190758 A

An object of the present invention is to provide a start clutch control device for an idle stop vehicle that can suppress belt slipping when switching to the travel range immediately after returning to the idle stop in the non-travel range.

To achieve the above object, the present invention provides an engine, an engine control device that automatically stops the engine when a predetermined stop condition is satisfied, and restarts the engine when a predetermined return condition is satisfied, and the engine An oil pump driven by the motor, a belt-type continuously variable transmission that transmits engine power to the drive wheels, a starting clutch provided between the engine and the continuously variable transmission, and a hydraulic pressure generated by the oil pump And a hydraulic control device that supplies hydraulic pressure to the continuously variable transmission and the starting clutch, and a shift position is either a travel range in which the start clutch is engaged or a non-travel range in which the start clutch is released. And a shift position detecting means for detecting the engine rotation speed of the engine for detecting the engine speed. Detecting means, belt clamping pressure detecting means for detecting belt clamping pressure of the continuously variable transmission, and restarting the engine satisfying the return condition while the engine is automatically stopped when the shift position is in a non-traveling range. First means for detecting that a command has been issued; and second means for detecting that the shift position has been switched from a non-traveling range to a traveling range after a restart command has been issued to the engine; A third means for determining whether or not the state in which the engine speed is equal to or higher than a predetermined value Ne and the belt clamping pressure is equal to or higher than a predetermined value Pb continues for a predetermined time ΔT or more at the time of switching to the travel range; If it is determined that the state has continued for a certain time or longer, the engine is not automatically stopped and the shift pattern is switched from the non-traveling range to the traveling range in the same first pattern. When the advance clutch is engaged, and it is determined that the state has not continued for a certain time or longer, the start clutch is engaged with a second pattern that increases the clutch pressure with a time gradient smaller than the first pattern. And a starting clutch control device for an idle stop vehicle.

The present invention assumes that the oil pump is stopped during idle stop, and that the oil pressure supplied to the continuously variable transmission and the starting clutch is eliminated. This relates to the control of the starting clutch. In this case, if normal clutch control (same clutch control as switching from N → D or R during engine driving) is performed on the starting clutch, belt slipping may occur as described above. Therefore, in the present invention, the engagement pattern of the starting clutch is switched to two types depending on whether or not the following conditions are met. The condition is whether or not the state in which the engine speed is equal to or greater than a certain value Ne and the belt clamping pressure is equal to or greater than a certain value Pb continues for a certain time ΔT at the time of switching to the travel range. Here, the constant engine speed Ne is a speed at which the oil pump can generate a desired discharge pressure, and is set to, for example, about 500 rpm. The constant belt clamping pressure Pb is a clamping pressure that can generate, for example, a belt transmission torque necessary for starting. The fixed time ΔT is a time during which the engine speed and the belt clamping pressure are stabilized, and may be set to about 1 to 2 seconds, for example. Of the two types of clutch engagement patterns, the first pattern is a normal clutch engagement pattern (engagement pattern similar to that when switching from N to D or R during engine driving). The initial pressure may be supplied, followed by sweep control, and finally fastening control. The second pattern is a pattern in which the time gradient of the clutch pressure is smaller than that of the first pattern. For example, the initial pressure may be set lower than normal, or the sweep control gradient may be set smaller.

As described above, since the two types of clutch engagement patterns are switched depending on whether or not the state in which the engine speed is equal to or higher than the predetermined value Ne and the belt clamping pressure is equal to or higher than the predetermined value Pb is continued for a predetermined time ΔT or more (Patent Document Compared with the case of changing only the elapsed time since switching to the travel range as in 2), stable clutch control is not affected by variations in the degree of increase in engine speed or belt clamping pressure. Can be implemented. In addition, when the first pattern is implemented, since the engine speed and the belt clamping pressure have already been sufficiently increased, there is no engagement shock and the time lag can be optimized. When the second pattern is implemented, the clutch pressure is gradually increased from the normal time, so that the occurrence of belt slip can be suppressed.

In the present invention, there is further provided a transmission torque calculating means for calculating the belt transmission torque of the continuously variable transmission from the detected belt clamping pressure, and the second pattern includes the belt transmission torque calculated from the clutch transmission torque of the starting clutch. It is good also as a pattern which controls the clutch pressure of a starting clutch so that it may not exceed. That is, at the time of low oil pressure immediately after the return to idle stop, belt slip prevention control is performed in which a predetermined initial pressure is not supplied to the starting clutch as a target clutch pressure but clutch pressure that does not cause belt slip is supplied. This belt slip prevention control is to control the clutch pressure so that the clutch transmission torque of the starting clutch does not exceed the belt transmission torque of the continuously variable transmission so that the target clutch pressure according to the belt transmission torque is obtained. In other words, the upper limit value of the target clutch pressure may be set to a hydraulic pressure corresponding to the belt transmission torque. Therefore, when the time from the idle stop return to the travel range is short, the starting clutch is engaged early, the belt clamping pressure of the continuously variable transmission is insufficient, and slip occurs between the belt and the pulley. Can be resolved. The belt transmission torque increases rapidly when the hydraulic oil is filled in the pulley oil chamber of the continuously variable transmission, but if the target clutch pressure is also increased following the belt transmission torque, an engagement shock may occur. . Therefore, the belt slip prevention control is performed only until the target clutch pressure reaches a predetermined value, and after the target clutch pressure reaches the predetermined value, the pressure increase control is performed similarly to the normal engagement control. .

The method for detecting the belt clamping pressure is arbitrary. For example, the hydraulic pressure of the secondary pulley of the continuously variable transmission may be detected by a hydraulic pressure sensor, and the belt clamping pressure may be calculated from the detected hydraulic pressure. Further, the belt clamping pressure may be estimated by measuring a value correlated with the belt clamping pressure, for example, a line pressure.

If the elapsed time from the engine restart until the target clutch pressure reaches the predetermined value (the period of belt slip prevention control) is shorter than the predetermined time, the target clutch pressure is held at the predetermined value until the predetermined time is reached. May be. In other words, the belt slip prevention control period varies depending on the rate of increase of the belt transmission torque, but when this period is shorter than the initial pressure supply period in normal clutch control, the clutch slip pressure is simultaneously with the end of the belt slip prevention control. When the pressure increase control is started, there is a possibility that the clutch is engaged too early and a shock occurs. Therefore, when the belt slip prevention control period is shorter than the predetermined time, the target clutch pressure is preferably maintained at a predetermined value (for example, initial pressure) until the predetermined time is reached. If it does in this way, the shock and time lag at the time of start can be optimized.

As described above, according to the present invention, when switching to the travel range immediately after returning to the idle stop in the non-travel range, the engine speed is equal to or higher than a certain value and the belt clamping pressure is switched to the travel range. Since the clutch engagement pattern is switched depending on whether or not the state where the value is equal to or greater than a certain value continues for a certain time or more, a shock can be avoided and belt slip can be suppressed at the same time.

It is a skeleton figure which shows an example of a structure of the idle stop vehicle which concerns on this invention. FIG. 2 is a hydraulic circuit diagram of the continuously variable transmission shown in FIG. 1. It is a figure which shows the detail of a garage shift valve. It is a figure which shows each characteristic of line pressure P _{L with} respect to solenoid pressure Psls, clutch modulator pressure Pcm, clutch control pressure, and secondary pressure. It is a time chart figure of an example of engagement control of a starting clutch at the time of idle stop return concerning the present invention. It is a flowchart figure of an example of engagement control of the starting clutch which concerns on this invention. It is a time chart figure of an example of starting clutch control at the time of the conventional idling stop return.

FIG. 1 shows an example of the configuration of an idle stop vehicle according to the present invention. An output shaft 1 a of the engine 1 is connected to a drive shaft (output shaft) 32 via a continuously variable transmission 2. The continuously variable transmission 2 is provided with a torque converter 3, a continuously variable transmission 4, a hydraulic control device 7, an oil pump 6 driven by the engine 1, and the like.

The continuously variable transmission 2 includes a forward / reverse switching device 8 that transmits the rotation of the turbine shaft 5 of the torque converter 3 to the primary shaft 10 by switching between forward and reverse, the primary pulley 11, the secondary pulley 21, and a V that is wound between the pulleys. The continuously variable transmission 4 having the belt 15, the differential device 30 that transmits the power of the secondary shaft 20 to the drive shaft 32, and the like. The turbine shaft 5 and the primary shaft 10 are arranged on the same axis, and the secondary shaft 20 and the drive shaft 32 are arranged parallel to the turbine shaft 5 and non-coaxially. Therefore, the continuously variable transmission 2 has a three-axis configuration as a whole. The V belt 15 used here is, for example, a known compression drive type metal belt composed of an endless tension band and a number of blocks slidably supported by the tension band.

The forward / reverse switching device 8 includes a planetary gear mechanism 80, a reverse brake (B1) 85, and a direct clutch (C1) 86, and the reverse brake 85 or the direct clutch 86 corresponds to the starting clutch in the present invention. The reverse brake 85 and the direct coupling clutch 86 are wet multi-plate brakes and clutches, respectively. A sun gear 81 of the planetary gear mechanism 80 is connected to the turbine shaft 5 as an input member, and a ring gear 82 is connected to the primary shaft 10 as an output member. The planetary gear mechanism 80 is a single pinion system, the reverse brake 85 is provided between the carrier 84 supporting the pinion gear 83 and the transmission case, and the direct coupling clutch 86 is provided between the carrier 84 and the sun gear 81. When the direct coupling clutch 86 is released and the reverse brake 85 is engaged, the rotation of the turbine shaft 5 is reversed, decelerated, and transmitted to the primary shaft 10. Then, the drive shaft 32 rotates in the same direction as the engine rotation direction via the secondary shaft 20, so that the vehicle travels forward. Conversely, when the reverse brake 85 is released and the direct clutch 86 is engaged, the carrier 84 and the sun gear 81 rotate together, so that the turbine shaft 5 and the primary shaft 10 are directly connected. Then, since the drive shaft 32 rotates in the direction opposite to the engine rotation direction via the secondary shaft 20, a reverse traveling state is set.

The primary pulley 11 of the continuously variable transmission 4 includes a fixed sheave 11a that is integrally fixed on the primary shaft 10 and a movable sheave 11b that is supported on the primary shaft 10 so as to be axially movable and integrally rotatable. I have. A cylinder 12 fixed to the primary shaft 10 is provided behind the movable sheave 11 b, and an oil chamber 13 is formed between the movable sheave 11 b and the cylinder 12. Shift control is performed by controlling the amount of oil supplied to the oil chamber 13.

The secondary pulley 21 includes a fixed sheave 21a that is integrally fixed on the secondary shaft 20, and a movable sheave 21b that is supported on the secondary shaft 20 so as to be axially movable and integrally rotatable. A piston 22 fixed to the secondary shaft 20 is provided behind the movable sheave 21 b, and an oil chamber 23 is formed between the movable sheave 21 b and the piston 22. By controlling the hydraulic pressure supplied to the oil chamber 23, a belt clamping pressure necessary for torque transmission is applied. The oil chamber 23 may be provided with a bias spring that applies an initial clamping pressure. In the supply oil passage in the vicinity of the oil chamber 23 of the secondary pulley 21, a hydraulic pressure sensor 108 that detects the supply oil pressure of the oil chamber 23 is provided as will be described later.

One end portion of the secondary shaft 20 extends toward the engine side, and the output gear 27 is fixed to this end portion. The output gear 27 meshes with the ring gear 31 of the differential device 30, and power is transmitted from the differential device 30 to the drive shaft 32 extending left and right to drive the wheels.

The engine 1 and the continuously variable transmission 2 are controlled by the electronic control unit 100. The electronic control unit 100 includes an engine speed sensor 101, a vehicle speed (or secondary pulley speed) sensor 102, a throttle opening (or accelerator opening) sensor 103, a shift position sensor 104, a primary pulley speed (or turbine speed). ) Signals are input from the sensor 105, the brake signal sensor 106, the CVT hydraulic oil temperature sensor 107, and the hydraulic pressure sensor 108 that detects the hydraulic pressure supplied to the secondary pulley 21. In addition, a road surface inclination angle, an idle signal, a start signal, an engine water temperature, an intake air amount, an air conditioner signal, an ignition signal, and the like may be input as input signals. For the sake of simplicity, FIG. 1 shows an example in which both the engine 1 and the continuously variable transmission 2 are controlled by a single electronic control unit 100, but in actuality, control is performed by individual electronic control units. Both electronic control units are linked to each other by a communication bus.

The electronic control unit 100 performs idle stop control that stops the engine 1 (idle stop) when a predetermined stop condition is satisfied, and restarts the engine 1 when a predetermined return condition is satisfied. As a condition for permitting the idle stop, for example, there is a brake ON (depressing the brake pedal). However, idling stop is not permitted when the engine water temperature is low, the electric load is large, or the accelerator pedal is depressed. On the other hand, idle stop return (engine restart) conditions include, for example, brake OFF, accelerator pedal depression, and input of a vehicle speed signal. Since the idle stop permission condition and the return condition are known, detailed description thereof is omitted here.

The electronic control device 100 controls a solenoid valve built in the hydraulic control device 7. The hydraulic control device 7 is connected to the oil pump 6, the oil chamber 13 of the primary pulley 11, the oil chamber 23 of the secondary pulley 21, the reverse brake 85, and the direct coupling clutch 86, respectively. The electronic control unit 100 determines the target primary rotational speed according to a shift map set in advance according to the vehicle speed and the throttle opening, and controls the solenoid valve in the hydraulic control unit 7 to thereby control the continuously variable transmission 2. The oil amount / hydraulic pressure of the oil chambers 13 and 23 of the primary pulley 11 and the secondary pulley 21 is adjusted to control the primary rotational speed to the target value, and the belt clamping pressure of the secondary pulley 21 is set to a value that does not cause belt slip. I have control. The hydraulic control device 7 also has a function of controlling the hydraulic pressure supplied to the reverse brake 85 and the direct coupling clutch 86, and this control includes the engagement control of the reverse brake (starting clutch) 85 from an idle stop state to be described later. Is also included.

FIG. 2 is a hydraulic circuit diagram of an example of the hydraulic control device 7. In FIG. 2, 71 is a regulator valve, 72 is a clutch modulator valve, 73 is a solenoid modulator valve, 74 is a garage shift valve, 75 is a manual valve, 76 is an upshift ratio control valve, 77 is a downshift ratio control valve, 78 is a ratio check valve and 79 is a clamping pressure control valve. Further, the SLS outputs the solenoid pressure Psls in order to perform pressure regulation control of the line pressure, transient control of the reverse brake 85 (B1) and the direct coupling clutch 86 (C1), and pressure regulation control of the oil chamber 23 of the secondary pulley 21. A pressure regulating solenoid valve, DS1 is an upshift solenoid valve for regulating the pressure of the upshift signal pressure Pds1, and DS2 is a downshift solenoid valve for regulating the pressure of the downshift signal pressure Pds2. In the present embodiment, the solenoid valve SLS uses a normally open linear solenoid valve, and the solenoid valves DS1 and DS2 both use a normally closed duty solenoid valve.

In FIG. 2, only the hydraulic circuit relating to the primary pulley 11, the secondary pulley 21, the reverse brake B1 and the direct coupling clutch C1 is shown. However, the hydraulic circuit of the lock-up clutch 3a built in the torque converter 3 is the same as that of the present invention. Omitted because there is no direct relationship. Note that the hydraulic pressure source of the hydraulic control device 7 is only the oil pump 6 driven by the engine 1, and no special oil pump such as an electric pump is provided.

The regulator valve 71 is a valve that regulates the discharge pressure of the oil pump 6 to a predetermined line pressure P _L, and regulates the line pressure P _L according to the solenoid pressure Psls input to the signal port 71a.

The clutch modulator valve 72 is a valve that outputs a clutch modulator pressure Pcm that is a source pressure of supply pressures (P _C1 , P _B1 ) to the direct coupling clutch C1 and the reverse brake B1. The line pressure P _L is input to the input port 72a, and the clutch modulator pressure Pcm is output from the output port 72b. The output pressure is fed back to the first signal port 72c so as to face the spring load. Therefore, the clutch modulator pressure Pcm is adjusted to a constant pressure corresponding to the spring load.

The solenoid modulator valve 73 is a valve that regulates the clutch modulator pressure Pcm and generates a constant solenoid modulator pressure Psm corresponding to the spring load. The solenoid modulator pressure Psm is the original pressure of the upshift solenoid valve DS1 and the downshift solenoid valve DS2, and is also supplied to the garage shift valve 74 and the clamping pressure control valve 79.

The manual valve 75 is a manually operated valve mechanically connected to the shift lever. The manual valve 75 is switched to each range of P, R, N, D, S, and B, and the hydraulic pressure supplied from the garage shift valve 74 is directly coupled to the clutch C1. Alternatively, it selectively leads to the reverse brake B1. The input port 75a is supplied with hydraulic pressure from the garage shift valve 74, the output port 75b is connected to the direct clutch C1, and the output ports 75c and 75d are both connected to the reverse brake B1. In the R range, the manual valve 75 supplies hydraulic pressure to the direct clutch C1 and drains the hydraulic pressure of the reverse brake B1. In the D, S, and B ranges, the manual valve 75 supplies hydraulic pressure to the reverse brake B1 and drains the hydraulic pressure of the direct clutch C1. In the P and N ranges which are non-traveling ranges, the hydraulic pressures of the direct clutch C1 and the reverse brake B1 are drained together.

The upshift ratio control valve 76 and the downshift ratio control valve 77 are supplied with and discharged into the oil chamber 12 of the primary pulley 11 by the relative relationship between the upshift signal pressure Pds1 and the downshift signal pressure Pds2. It is a valve that adjusts. Further, the ratio check valve 78 switches the oil chamber 12 of the primary pulley 11 from the flow rate control to the hydraulic control for closing control so that the oil pressure of the oil chamber 12 of the primary pulley 11 and the oil chamber 23 of the secondary pulley 21 are controlled. It is a valve for maintaining the ratio with the hydraulic pressure in a preset relationship and maintaining the gear ratio. The upshift ratio control valve 76 and the downshift ratio control valve 77 are known from, for example, Japanese Patent Application Laid-Open No. 2007-263207, and the description thereof is omitted.

The clamping pressure control valve 79 is a valve for controlling the hydraulic pressure of the hydraulic oil chamber 23 of the secondary pulley 21 and includes a spool biased in one direction by a spring. A constant pressure Psm is supplied from the solenoid modulator valve 73 to the signal port 79a at one end facing the spring load. Line pressure P _L is supplied to the input port 79b, the output port 79c is connected to the hydraulic oil chamber 23 of the secondary pulley 21, and the output pressure is fed back to the port 79d. Solenoid pressure Psls is supplied to the signal port 79e on the other end side in which the spring is accommodated. Therefore, the hydraulic pressure obtained by amplifying the solenoid pressure Psls input to the signal port 79e with a predetermined amplification degree can be supplied to the hydraulic oil chamber 23. The hydraulic pressure supplied to the hydraulic oil chamber 23 is detected by the hydraulic pressure sensor 108, and the belt transmission torque can be obtained based on the detected hydraulic pressure.

The garage shift valve 74 is for switching the oil path so that the supply pressure to the direct coupling clutch C1 and the reverse brake B1 can be transiently controlled when the shift lever is switched from N to D or from N to R (in garage shift). It is a switching valve. FIG. 3 shows the detailed structure of the garage shift valve 74. The left side of the center line is a transient state and the right side is a holding state. A spool 74b is inserted into the valve body 74a so as to be movable in the axial direction, and a spring 74c for urging the spool 74b in one direction is provided at one end. One end of the valve body 74a is provided with signal ports 74d and 74e to which the upshift signal pressure Pds1 and the downshift signal pressure Pds2 are input in the same direction as the spring load. On the other end side of the valve body 74a, a counter port 74f to which the solenoid modulator pressure Psm is input in a direction opposite to the spring load is provided. The pressure receiving area of the spool 74b in the counter port 74f is set equal to the sum of the pressure receiving areas of the spool 74b in the signal ports 74d and 74e to which the signal pressures Pds1 and Pds2 are input. An intermediate part of the valve body 74a includes an input port 74g to which the clutch modulator pressure Pcm is input, an input port 74h to which the solenoid pressure Psls is input, and an output port 74i connected to the input port 75a of the manual valve 75. Is provided.

FIG. 4 shows the characteristics of the line pressure P _L , the clutch modulator pressure Pcm, the clutch control pressure, and the secondary pressure with respect to the solenoid pressure Psls. The line pressure P _L is adjusted to a hydraulic pressure substantially proportional to the solenoid pressure Psls. The clutch modulator pressure Pcm is the same as the line pressure P _L until the solenoid pressure Psls reaches a predetermined value, and is controlled to a constant pressure when the pressure exceeds the predetermined value. Further, since the solenoid pressure Psls is directly supplied to the reverse brake B1 or the direct coupling clutch C1 in a transient state, the clutch control pressure becomes the solenoid pressure Psls itself. The secondary pressure is proportional to the solenoid pressure Psls and is adjusted to a hydraulic pressure slightly lower than the hydraulic line pressure P _L.

Here, the engagement control of the starting clutch (B1) at the time of idle stop return (engine restart) in the present invention will be described with reference to FIG. FIG. 5 shows the clutch hydraulic pressure and the belt clamping pressure, both of which can be controlled by the solenoid valve SLS. The belt clamping pressure can be calculated based on the oil pressure of the oil chamber 23 of the secondary pulley 21 detected by the oil pressure sensor 108.

For example, when a predetermined return condition (for example, brake OFF) is satisfied at time t1 while the vehicle is stopped in the N range, an idle stop return command is output, and the engine speed starts to gradually increase due to cranking. Subsequently, when the shift lever is switched to the D range at time t2 (case 1), at this time, the state where the engine speed is equal to or higher than a predetermined value Ne and the belt clamping pressure is equal to or higher than a predetermined value Pb as described later. Since it does not continue for ΔT or more, the clutch pressure of the starting clutch is controlled by the second clutch engagement pattern. As the second clutch engagement pattern, the belt transmission possible torque of the secondary pulley 21 is calculated based on the secondary clamping pressure detected by the hydraulic sensor 108, and the clutch transmission torque of the starting clutch exceeds the calculated belt transmission torque. The target clutch pressure is set so as not to occur, and the clutch pressure is controlled to approach the target value. For the belt transmission torque, the hydraulic pressure of the secondary pulley 21 is detected by the hydraulic pressure sensor 108, the secondary clamping pressure is calculated from the secondary pressure and the pressure receiving area, and the secondary clamping pressure, the friction coefficient with the belt, the winding diameter, etc. Secondary transmission torque can be calculated. In FIG. 5, the broken line Pr indicates the clutch pressure corresponding to the belt transmission torque, and the solid line Pa indicates the actual clutch pressure. Therefore, the clutch transmission torque of the starting clutch does not exceed the belt transmission torque of the continuously variable transmission, and belt slip can be suppressed.

At time t3 when the cranking period ends, the engine speed rapidly increases, and accordingly, the discharge pressure of the oil pump increases and the belt clamping pressure also increases. When the target clutch pressure rises to a predetermined value corresponding to the initial pressure at time t4, the clutch hydraulic pressure of the starting clutch is maintained at a predetermined value corresponding to the initial pressure instead of the target clutch pressure corresponding to the belt transmission torque after time t4. And a sudden increase in clutch transmission torque is suppressed.

When the supply of the initial pressure is completed at time t5, the pressure increase control (sweep control) is started with a certain time gradient from the initial pressure. The clutch transmission torque gradually increases with the boost control. When the synchronized state is reached at time t6, the starting clutch is completely engaged. In this example, since the turbine rotation speed is not detected, the initial pressure supply period (t2 to t5) is set to a predetermined period corresponding to the oil temperature. However, when the turbine rotation speed is detected, the turbine rotation speed is determined. The time point when the number starts to deviate from the engine speed (out of synchronization) may be set as the initial pressure supply end point.

In the above-described control, after the target clutch pressure has increased to a predetermined value at time t4, the pressure is not immediately shifted to the pressure increase control but is maintained at a predetermined value corresponding to the initial pressure until time t5. This is a case where the period is shorter than the normal initial pressure supply period, and if the belt clamping pressure rises slowly and the period from t2 to t4 becomes longer than the normal initial pressure supply period, immediately from time t4. You may transfer to step-up control. In addition, after the target clutch pressure rises to a predetermined value, a predetermined time may be awaited when shifting to the pressure increase control, or a condition that the CVT original pressure (line pressure) is a certain value or more may be added. . In this case, it is possible to cope with variations in oil temperature, idle stop time, clutch characteristics, and the like.

On the other hand, when the shift lever is switched to the D range at a time t7 after a certain amount of time has elapsed from the idle stop return command (case 2), before the time t7, a period Δte in which the engine speed is equal to or greater than a predetermined value Ne, A period Δtb in which the belt clamping pressure is equal to or greater than a certain value Pb is obtained, and these times are compared with a preset time ΔT. If Δte ≧ ΔT and Δtb ≧ ΔT, that is, if the engine speed is equal to or greater than a certain value Ne and the belt clamping pressure is equal to or greater than a certain value Pb, the first is continued. The clutch pressure of the starting clutch is controlled with the clutch engagement pattern. Here, Ne is an engine speed at which the oil pump can generate a desired discharge pressure, and is set to about 500 rpm, for example. Pb is, for example, belt clamping pressure that can generate belt transmission torque necessary for starting. ΔT is the time during which the engine speed and the belt clamping pressure are stabilized, and is set to, for example, about 1 to 2 seconds. In Case 2, since both the engine speed and the belt clamping pressure have increased to the normal state, clutch control similar to normal clutch control (garage shift) is performed. That is, as indicated by Pc in FIG. 5, the initial pressure is supplied for a predetermined time from time t7 to time t8, the pressure increase control (sweep control) is performed from time t8 to time t9, and the starting clutch is completely completed at time t9. Engage.

FIG. 6 is a flowchart of an example of clutch engagement control in the present invention. First, it is determined whether or not an idle stop return command has been issued (step S1). If no command has been issued, the flag F = 0 is determined (step S2). F = 0 is a normal engagement pattern (garage shift pattern) and corresponds to case 2 shown in FIG. On the other hand, F = 1 is an engagement pattern (idle stop return pattern) at the time of idle stop return, and corresponds to the case 1 shown in FIG. If an idle stop return command is issued, it is next determined whether the engine speed is equal to or greater than a certain value Ne and the belt clamping pressure is equal to or greater than a certain value Pb (step S3). If either one is not satisfied, flag F = 1 is set (step S5). If the engine speed is equal to or greater than a certain value Ne and the belt clamping pressure is equal to or greater than a certain value Pb, it is determined whether or not this state has continued for a certain time ΔT (step S4). If it is less than the predetermined time, the flag F is set to 1 (step S5), and if it continues for a predetermined time or more, the flag F is determined to be 0 (step S2).

Next, it is determined whether or not the shift position has been switched from N → D or N → R (step S6). When switched, it is determined whether the flag F is 0 or 1 (step S7). If F = 0, the clutch is engaged in a garage shift pattern (step S8), and if F = 1, idle is performed. The clutch is engaged with the stop return pattern (step S9).

In the above-described embodiment, the case where the start clutch is the reverse brake (B1) 85 has been described as an example in order to start forward travel when returning to idle stop. However, when starting reverse travel, the start clutch is a direct clutch. (C1) 86.

The hydraulic circuits of the continuously variable transmission and the starting clutch are not limited to those shown in FIGS. When starting with the return to idle stop, the hydraulic pressure can be immediately supplied to the continuously variable transmission, and the configuration is optional as long as the starting clutch can be supplied with a hydraulic pressure approximately proportional to the command current to the solenoid valve. is there. FIG. 2 shows an example in which the clamping control of the secondary pulley 21 and the engagement control of the start clutch 85 are performed using the common solenoid valve SLS. However, the present invention is not limited to this. The hydraulic control of both may be performed using

DESCRIPTION OF SYMBOLS 1 Engine 2 Continuously variable transmission 3 Torque converter 4 Continuously variable transmission 5 Turbine shaft 6 Oil pump 7 Hydraulic control device 8 Forward / reverse switching device 11 Primary pulley 21 Secondary pulley 74 Garage shift valve 79 Nipping pressure control valve 85 (B1) Reverse rotation Brake (starting clutch)
86 (C1) Direct coupling clutch 100 Electronic control unit 101 Engine speed sensor 102 Vehicle speed sensor 103 Throttle opening sensor 104 Shift position sensor 105 Primary pulley speed sensor 106 Brake sensor 107 Oil temperature sensor 108 Oil pressure sensor SLS Solenoid valve DS1 Solenoid valve DS2 Solenoid valve

Claims (2)

Engine,
An engine control device that automatically stops the engine when a predetermined stop condition is satisfied, and restarts the engine when a predetermined return condition is satisfied;
An oil pump driven by the engine;
A belt-type continuously variable transmission that transmits engine power to drive wheels;
A starting clutch provided between the engine and the continuously variable transmission;
A hydraulic control device for supplying hydraulic pressure to the continuously variable transmission and the starting clutch based on the hydraulic pressure generated by the oil pump;
In an idle stop vehicle comprising a shift position detecting means for detecting whether a shift position is a travel range in which the start clutch is engaged or a non-travel range in which the start clutch is released,
Engine speed detecting means for detecting the engine speed;
Belt clamping pressure detecting means for detecting belt clamping pressure of the continuously variable transmission;
A first means for detecting that a restart command is issued to the engine while satisfying the return condition while the engine is automatically stopped when the shift position is in a non-traveling range;
Second means for detecting that the shift position has been switched from a non-traveling range to a traveling range after a restart command is issued to the engine;
A third means for determining whether or not the state where the engine speed is equal to or greater than a certain value Ne and the belt clamping pressure is equal to or greater than a certain value Pb continues for a certain time ΔT at the time of switching to the travel range;
When it is determined that the state has continued for a certain time or more, the engine is not automatically stopped, and the start clutch is engaged in the same first pattern as when the shift position is switched from the non-traveling range to the traveling range. A fourth means for engaging the start clutch in a second pattern that raises the clutch pressure with a time gradient smaller than the first pattern when it is determined that the state has not continued for a certain period of time; A start clutch control device for an idling stop vehicle. A transmission torque calculating means for calculating a belt transmission torque of the continuously variable transmission from the detected belt clamping pressure;
The said 2nd pattern is a pattern which controls the clutch pressure of the said starting clutch so that the clutch transmission torque of the said starting clutch may not exceed the calculated belt transmission torque. A start clutch control device for an idle stop vehicle as described.

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