JP2956333B2 - Transmission control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a shift control apparatus for line Umudan transmission stepless by changing the diameter ratio winding belt that is wound around a pair of pulleys by switching operation of the hydraulic actuator.

[0002]

Conventionally, wound around the drive belt between the primary pulley and the secondary pulley, a continuously variable transmission of the belt drive to perform continuously variable by changing the diameter ratio winding belt that is wound around the pulleys Machines are known. This continuously variable transmission includes both hydraulic actuators for operating the relative distance between the fixed-side pulley member and the movable-side pulley member of both the primary and secondary pulleys, and the gear ratio vehicle determined according to the driving information of the vehicle. a gear ratio determined in accordance with the operation information
Supplied to the primary hydraulic actuator
Controls the hydraulic pressure and determines it according to the driving information of the vehicle.
Secondary hydraulic actuator to achieve
It is configured to control the hydraulic pressure supplied to the motor .

[0003]

Where [0005] back when vehicles are such as to stop entering the sudden braking state during overdrive, the wrapping ratio of the primary pulley and the secondary pulley of the continuously variable transmission of the state of Fururo That means
Without returning to this case completely, breaks in the middle of, fall into a state that does not given enough tension on the belt. As a result,
At the start of the next vehicle, a belt slip occurs,
There is a problem in that slippage between the belt and the pulley is likely to occur, uneven wear on the belt and the pulley is likely to occur, and damage is caused.

An object of the present invention is to provide a shift control device for a continuously variable transmission which can prevent both pulleys from being damaged during a sudden braking.

[0005]

According to a first aspect of the present invention, there is provided a primary pulley connected to an engine side, a secondary pulley connected to a drive shaft side, and a hook between the two pulleys. The vehicle endless belt includes a transferred endless belt, a primary hydraulic actuator for changing a winding diameter of the endless belt on the primary pulley side, and a secondary hydraulic actuator for changing a winding diameter of the endless belt on the secondary pulley side. In a shift control device for a stepped transmission, primary pulley control means for setting a target primary pulley rotation speed according to the engine load, and controlling a hydraulic pressure supplied to the primary hydraulic actuator according to the target primary pulley rotation speed, The secondary hydraulic actuator is operated according to the driving state of the vehicle. A line pressure setting means for setting a line pressure supplied to the motor, a low-speed range determination means for determining whether or not the primary pulley rotation speed is lower than a predetermined low-speed range determination value; A line pressure correcting means for increasing and correcting the line pressure, and storing a cycle proportional to an increase in the rotation speed of the primary pulley so as to intermittently supply a predetermined control oil pressure to the primary hydraulic actuator in each cycle. a control hydraulic pressure intermittent output setting means for setting, when it is determined that the low speed range by the low speed region determining means, is set by the control oil pressure intermittent output setting means
The predetermined control hydraulic pressure is the primary hydraulic actuator
Controls the primary pulley control means so that it is supplied to the
And the low-speed range is determined by the low-speed range determination means.
For a predetermined time after the stop state is detected and the
The line pressure corrected by the in-pressure correction means is
The above-mentioned line is supplied to the candali hydraulic actuator.
Shift control means for controlling the in-pressure setting means .

[0006] A second aspect of the present invention is a pump connected to the engine.
Primary pulley and secondary pulley connected to the drive shaft
And the endless belt stretched between both pulleys
Winding the endless belt on the primary pulley side
Primary hydraulic actuator for changing the diameter
The winding diameter of the endless belt on the cantilever pulley side
Changing the secondary hydraulic actuator and consisting of the car
In the shift control device for a two-way continuously variable transmission, the engine
Set the target primary pulley rotation speed according to the load, and
The above primary oil according to the target primary pulley rotation speed
Primary that controls the oil pressure supplied to the pressure actuator
Pulley control means and the security control means according to the driving state of the vehicle.
Set the line pressure supplied to the kandari hydraulic actuator.
Line pressure setting means and the primary pulley rotation speed
Low speed range to determine whether it is lower than a predetermined low speed range determination value
The determining means and the low-speed area determining means determine that the low-speed area has been determined.
After that, a start request determination step to determine whether a start request has been made
And stage start request is detected by the start request determining hands stage
The primary hydraulic actuator for a predetermined time
After the maximum oil pressure is supplied to the
Lower than the above maximum hydraulic pressure to the primary hydraulic actuator
The primary pulley control means is set so that a predetermined hydraulic pressure is supplied.
Shift control means for controlling the speed .

[0007]

In the first invention, the primary pulley control means sets the target primary pulley rotation speed according to the engine load, controls the hydraulic pressure supplied to the primary hydraulic actuator according to the target primary pulley rotation speed, and sets the line pressure. The setting means sets the line pressure to be supplied to the secondary hydraulic actuator in accordance with the driving state of the vehicle, and determines whether the primary pulley rotation speed is lower than a predetermined low-speed range determination value by the low-speed range determining means, The pressure compensating means compensates for the increase of the line pressure, the control oil pressure intermittent output setting means memorizes a cycle proportional to the increase of the primary pulley rotation speed, and intermittently applies a predetermined control oil pressure to the primary hydraulic actuator at the same cycle. When the transmission is set to be supplied and the shift control unit determines that the speed is in the low speed range, the control hydraulic intermittent output setting unit sets
The set control hydraulic pressure is the primary hydraulic actuator
Control the primary pulley control means so that
At the same time as the low speed range
Within a predetermined time after the
Line pressure is supplied to the secondary hydraulic actuator.
The line pressure setting means can be controlled so that
Intermittent oil to primary pulley hydraulic actuator
Can be supplied and refilled, and stop condition detected in low speed range
After that, the pressure compensated
It can be filled by supplying in pressure.

In the second invention, the primary pulley control means
Stage is the target primary pulley rotation speed according to the engine load
Set according to the target primary pulley rotation speed.
Controls the hydraulic pressure supplied to the Imari hydraulic actuator,
The in-pressure setting means sets the secondary oil according to the driving state of the vehicle.
Set the line pressure supplied to the pressure actuator,
The primary pulley rotation speed is set to a predetermined low speed by the
Start request determination means that determines whether the value is lower than the area determination value.
Is determined to be in the low speed range by the low speed range determination means,
The shift control means determines whether or not there has been a start request.
When the primary hydraulic actuator is
Maximum hydraulic pressure is supplied and a predetermined time between elapsed after plies to eta
Predetermined oil pressure lower than the maximum oil pressure for the Mari hydraulic actuator
Control the primary pulley control means so that
To the primary hydraulic actuator when starting
Oil can be filled.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The continuously variable transmission shown in FIG. 1 has a continuously variable transmission 2 on a power transmission system P connected to an engine 60 of a vehicle.
It is attached to 0. Here, the engine 60 is an electronically controlled fuel injection type four-cycle engine, such as an injector 1 for injecting fuel and a spark plug 2 for igniting an air-fuel mixture.
Various devices are DBWE as electronic control means of engine
It is placed under the control of CU3, and this DBWECU3
Is connected to a CVT ECU 21 which is an electronic control unit of a continuously variable transmission (CVT) 20 in the power transmission system P. The two ECUs 3 and 21 are connected by a communication line so that signals can be exchanged between the two ECUs 3 and 21 at all times.

The DBWECU 3 is connected to an actuator 11 for driving a throttle valve 9 as an intake air amount operating means which is driven independently of the operation of an accelerator pedal 10 as an artificial operating member. electromagnetic control valve 40 for adjusting the electromagnetic control valve 23 and the line pressure for hydraulic control of the transmission speed of the variable transmission 20 is connected.

Here, the overall configuration of the engine 60 will be briefly described. The flow rate of the intake air sucked from the air cleaner element 5 is measured by a Karman vortex airflow sensor 6 immediately after the intake air. In the air cleaner body 4, in addition to the air flow sensor 6, devices such as an atmospheric pressure sensor and an atmospheric temperature sensor (not shown) are provided, and various data relating to the intake air are measured and input to the DBWECU 3. It has a well-known configuration.

The amount of intake air flowing into the throttle body 8 from the air cleaner body 4 via the intake pipe 7 is controlled by a butterfly type throttle valve 9. The throttle valve 9 is opened and closed by an actuator (in this embodiment, a step motor) 11, not by an accelerator pedal 10 depressed by the driver. In this embodiment,
A so-called DBW (drive-by-wire) system in which the actuator 11 is controlled by the DBWECU 3 is employed. In the figure, reference numeral 12 denotes a throttle position sensor (hereinafter, a throttle sensor) that outputs opening degree information of the throttle valve 9 as intake air amount information, and a detection signal thereof is input to the DBWECU 3.
Incidentally, the accelerator opening sensor 13 as an acceleration request detection means is attached to the accelerator pedal 10, the depression amount θa is are entered into DBWECU3 is converted into an electric signal as acceleration requirement information of the driver.

The intake gas flows into the intake manifold 15 from the throttle body 8 via the surge tank 14, and becomes an air-fuel mixture by the fuel injected from the injector 1 according to a command from the DBWECU 3. The air-fuel mixture becomes exhaust gas after the explosion / expansion process of the engine 60 ends, flows into the exhaust manifold 16, and after harmful components are removed through an exhaust gas purification device (not shown), the mixture is introduced into the atmosphere from a muffler (not shown). Has been released. Reference numeral 24 denotes an engine rotation sensor that outputs engine rotation information. Reference numeral 61 denotes a speed detector that is mounted on a speed selection lever (not shown) and that outputs speed information. The fluid coupling 41 is attached to the crankshaft of the engine 60.
4 is connected via a planetary gear type forward / reverse switching device 42.

Here, the continuously variable transmission 20 has a primary pulley 26 having a primary shaft 22 integrally connected to an output shaft of a forward / reverse switching device 42 and a secondary shaft 29 having a secondary shaft 29 for outputting torque to the speed reducer 30 side. A pulley 28 is provided, and a steel belt 27 is stretched over the primary pulley 26 and the secondary pulley 28. The secondary shaft 29 is configured to transmit torque to the drive wheels 32 of the drive shaft 31 via a speed reducer 30 and a differential (not shown). As shown in FIG. 4, both the pulleys 26 and 28 are configured in two parts, and the movable side pulley members 261 and 281 are externally fitted to the fixed side pulley members 262 and 282 so that the relative pulleys can be relatively separated from and separated from each other. . The movable pulley members 261 , 281 and the fixed pulley member 26
2 and 282, a primary cylinder 33 as a hydraulic actuator for operating the relative distance between the two pulleys.
And a secondary cylinder 34 are formed .

A pair of rotation sensors s1 and s2 for detecting the rotational speeds Wp and Ws of the primary pulley 26 and the secondary pulley 28 are mounted as means for detecting the actual speed ratio In (= Wp / Ws). In this case, by moving the movable pulley 261 closer to the fixed pulley 262 of the primary pulley 26 and increasing the winding diameter of the primary pulley, the movable pulley 281 is separated from the fixed pulley 282 of the secondary pulley 28. the winding diameter is small, the high gear position, and is configured so as to achieve low gear position by operating in reverse. The hydraulic circuit of the continuously variable transmission 20 will be described with reference to FIG. The hydraulic circuit includes an oil pump 37, and the discharge oil is supplied to the fluid coupling 41, the forward clutch 43 and the reverse clutch 44 of the forward / reverse switching unit 42, and the primary cylinder 33 and the secondary cylinder 34 of the continuously variable transmission 20. You.

Here, the oil pump 37 is driven in accordance with the rotation of the engine, changes its oil pressure and supplies it to the line pressure line 49. Line pressure Lilly in this order line pressure passage 49 for restricting the maximum allowable pressure of the discharge pressure of the oil pump 37
Off valve 47 is mounted, moreover regulator valve 48 so as pressure regulating the line pressure to the set value is attached. The regulator valve 48 changes the oil pressure of the line pressure port 481 to the drain port 483 according to the rightward movement of the land 482.
And adjust the oil pressure. The hydraulic pressure adjustment is performed by the pilot pressure supplied to the left end of the spool 484 and the spring 63.
And the control hydraulic pressure supplied to the right end of the spool
This is performed by the balance operation of the screw 64. The pilot pressure is adjusted by a modulator valve 53 described later.
That is, the regulator valve 4 8 is controlled by CVTECU21 via the conductive magnetic control valve 40.

Part of the line pressure line 49 is a clutch module.
Is connected to over motor valve 50, hydraulic fluid pressure regulated to the set value by Doben is supplied to the manual valve 52 through the clutch oil passage 51. The manual valve 52 is interlocked with a manual shift lever for shifting gears, so that the forward side D,
2 and L, a reverse R range, and a neutral N and parking P range. The manual valve 52 connects the forward clutch 43 and the clutch oil passage 51 when the range is forward D, 2 or L, and
Chi is joined . At this time, the engine rotation is transmitted to the continuously variable transmission 20 in the forward rotation direction , while the engine rotation is reversed and transmitted to the continuously variable transmission 20 in the reverse R range. A part of the line pressure line 49 branches off and is adjusted to a set value by the modulator valve 53, and the oil pressure is adjusted to a predetermined value by the electromagnetic control valves 23 and 40, and each is adjusted as a control pressure.
The right end of the regulator 48 and a speed ratio control
The lube 54 is supplied to the right end.

The primary cylinder 33 of the continuously variable transmission 20
And the secondary cylinder 34 are respectively connected to a main port 541 and a sub port 542 of the speed ratio control valve 54,
In particular, the secondary cylinder 34 is directly connected to the line pressure path 49. Here, the gear ratio control valve 54 is
In addition to 41, 542, the shift control oil pressure P of the electromagnetic control valve 23
c, a pilot port 543 for receiving the pressure from the modulator valve 53, and a drain port X communicating with the oil tank 55. The spool 56 controls the switching of the oil path. .

Here, the spool 56 opposes the pilot port 543 and receives the shift control pressure Pc leftward, and the other end receives the adjustment pressure and spring force in the opposite direction, and switches to the balance position. In this case, the spool 56
The drain port X is closed in response to the rightward movement (the shift control oil pressure Pc decreases), is completely closed after the constant movement, and the communication port between the main port 541 and the sub port 542 increases after the constant movement. The primary pulley control hydraulic pressure Pp of the primary cylinder 33 is increased (the secondary pulley control hydraulic pressure Ps is normally a line pressure), and the actual gear ratio In
Reduces the the high gear position, the reverse leftward movement of the spool 56 (speed change control hydraulic pressure Pc is increased) is released drain port X in response to the reduce the primary pulley control pressure Pp (secondary pulley control pressure Ps is normal state line pressure), increases the actual gear ratio in a low gear position that it is possible. In addition, the electromagnetic control valve 2 that generates the shift control hydraulic pressure Pc
3 is that if the duty ratio Du it receives is low, the hydraulic pressure Pc
And the hydraulic pressure Pc is increased when the duty ratio Du is high.

The main parts of the DBWECU 3 and the CVT ECU 21 are both constituted by a microcomputer.
In particular, the built-in storage circuit stores and processes the maps of FIGS. 5 to 9 and the shift control programs as shown in FIGS. Here, the target primary pulley rotation speed calculation map in FIG. 5 is used to calculate the target primary pulley rotation speed Wpo during normal operation according to the throttle opening θs (or the accelerator opening θa). The target secondary cylinder oil pressure calculation map in FIG.
It is used to calculate the target oil pressure Pso from e, the gear ratio I, and the vehicle speed V. The primary pulley hydraulic pressure output cycle calculation map of FIG. 7 is used when the set level pulley control hydraulic pressure Pp is intermittently supplied to the primary pulley in the low speed control range described later at a set cycle S, and the cycle S is the primary pulley hydraulic cycle. It is set so as to increase in a quadratic curve in accordance with an increase in the rotation speed Wp. The intake air amount calculation map of FIG. 8 is used to calculate an intake air amount according to the slot opening θs and the engine speed Ne. Torque calculating map in FIG. 9 Ru used to calculate the input torque Te from the suction air amount A / N and the engine speed Ne.

Hereinafter, a shift control device for a continuously variable transmission according to the present embodiment will be described with reference to control programs shown in FIGS. 10 to 13 and a block diagram shown in FIG. In this embodiment,
By operating an ignition key (not shown), the engine body 60 is started, and the DBWE shown in FIGS.
The control in the CU 3 and the CVT ECU 21 is also started.
The DBWECU 3 controls the fuel injection valve 1 associated with the fuel supply amount control.
The driving process of the ignition plug 2, the driving process of the spark plug 2 accompanying the ignition timing control, and the driving process of the throttle valve accompanying the engine output control are executed according to a known program.

On the other hand, the CVT ECU 21 starts the shift control of the continuously variable transmission shown in FIGS. 10 to 17, makes initial settings in the main routine of FIG. 10, and detects primary pulley 26 and secondary pulley which are detection data of each sensor. , The throttle opening θa from the DBWECU 3, the throttle opening θs, the engine speed Ne,
The gear position information and the like from the gear position detector 61 are fetched and stored in a predetermined area. Primary pulley rotation speed in step a 2 Wp and the secondary pulley rotational speed W
s and the actual speed ratio In, and in step a3, the speed reduction ratio r of the speed reducer 30 and the secondary pulley rotation speed Ws
The vehicle speed V is calculated, and in step a4, the target primary pulley rotation speed Wpo is calculated from the throttle opening θs. Further, in step a5, the secondary pulley rotation speed Ws is differentiated to calculate the absolute value | ΔV | of the deceleration rate, and stores the calculated value in a predetermined area. Further, in step a6, the intake air amount A / N is calculated from the engine speed Ne and the throttle opening θs, the input torque Te is calculated from the intake air amount A / N and the engine speed Ne, and stored in a predetermined area. I do.

Thereafter, a control process during braking in step a7 is performed. In the brake control process, FIG.
As shown in FIG. 2, first, the control mode is determined. In the brake mode M1, the process proceeds to step b2. In the non-brake normal mode M0, the process proceeds to step b3, and the process returns to the main routine. In the control mode determination process shown in FIG. 12, first, at step b4, the vehicle speed V is 50 km
/ H or not, and if so, go to step b5 to prevent the continuously variable transmission from over-rotating due to a high-speed downshift .
Clear the advance brake flag, and in the following, step b6
Proceed to.

Here, the current input torque is a specified value, for example, 0
(Kg · fcm), that is, whether or not the engine is being braked. If it is not the engine brake, the brake flag is cleared in step b7. If the engine is in the brake state, the process proceeds to step b8.

In step b8, the deceleration rate | ΔV | is set to a predetermined value α2 for brake mode determination (for example, (7 km / h) / s).
ec), and if so, the step
In step b10, the brake control flag is set, and the brake mode is regarded as M1. Deceleration rate | [Delta] V | is lower than the predetermined value alpha 2 for determining braking mode, in particular, a predetermined value α1 of brake release determination (e.g. (4Km / h) / sec) and lower than the non-clears the brake flag in step b11 It is assumed that the brake mode is M0. That is, here, as shown in the mode setting map m4 in FIG. 2, a difference is provided between the determination value for the determination of the brake mode and the determination value for whether the brake is released, so that hunting does not occur in the control.

[0026] After this, in the case of the brake control flag set, to reach the step b12 from step b2. Here, the target secondary pulley pressure is set to the maximum value of the line pressure (the duty ratio to the electromagnetic control valve 40 is 100%),
In step b13, the target primary pulley rotation speed Wpo is directly set according to the throttle opening θs from the m1 map in FIG . In this way when the brake, the maximum hydraulic pressure is supplied to the secondary cylinder 34, the winding diameter of belt 27 by the secondary pulley 28 can be activated early so that the maximum value, along with this, the ply
The winding diameter of the Mari pulley 26 moves to the minimum side early.
Belt slack is prevented and the vehicle restarts after stopping
Sometimes slip between the belt and the pulley is prevented .

Next, when the brake control flag is cleared,
The process proceeds to step b3 through Step b14. Here the target hydraulic pressure Pso of the input torque T of the secondary cylinder 34
e, actual speed ratio In, vehicle speed V, and the like . In this case, the value calculated from the input torque Te and the actual gear ratio In using the m2 map of FIG.
Target oil pressure Pso which is the line pressure of secondary pulley 28
To determine. As a result, the line pressure that has been rapidly increased at the time of braking can be returned to the normal value. Subsequently, in step b15, the target primary pulley rotation speed Wpo corresponding to the throttle opening degree θs is calculated from the m1 map, stored, and the process returns to the main routine.

As a result, in the normal operation state, the line pressure, the target primary pulley rotation speed Wpo, and the ratio control gain K3 return to the normal values, and the durability of the continuously variable transmission is maintained.

Returning to the main routine, step a8 is reached, the current gear position information is fetched, and the vehicle moves to step a9 when traveling back and forth outside the P and N ranges, and to step a10 when traveling in the P and N ranges. move on. When the vehicle is traveling back and forth, the process proceeds to low speed control (a) in step a9 (see FIG. 13), and enters into low speed control determination. In the low-speed control (a) first, in step c 3
Currently in low-speed control, that is, the previously set low-speed control flag
Determine whether it is on . Advances the low-speed control flag is not on in step c6, the primary pulley rotation speed Wp is whether below the low speed region determination value (e.g., 11 rpm)
Judge . Can be below the same determination value, it is determined that the low speed range is set low <br/> deceleration control flag, directed to the process of step c2. Incidentally, when the low-speed control flag in step c 3 proceeds to step c4 ON, the primary pulley rotation speed Wp is slow
If it is not less than the range determination value , the low speed control flag is cleared, and the process proceeds to the normal traveling mode.

When the low speed control flag is on , step c
It reaches c8 from 2. Not shown in step c8
Within a predetermined time (for example, 3 seconds) after stopping
It is determined whether or not . Here if it is within a predetermined time period to hold the pulley control pressure Ps to the cell Kanda <br/> Ripuri 28 to the maximum line pressure (e.g. 20Kgf / cm ^2), after a predetermined time has elapsed, the process proceeds to step c10, target secondary pulley The control oil pressure Pso is calculated using the m2 map of FIG. 6 according to the input torque Te, the actual gear ratio In, and the vehicle speed V. In this case, the value calculated from the input torque Te and the actual gear ratio In is appropriately corrected according to the increase in the vehicle speed V, and the target hydraulic pressure Pso, which is the line pressure of the secondary pulley, is determined.

[0031] Proceeding from this step c8 to step c11, first calculates the set cycle S (see primary pulley hydraulic output period calculation map of FIG. 7) in accordance with the increase in the primary pulley speed Wp, according to the same period Predetermined level
Pulley control hydraulic pressure Pp intermittent to primary hydraulic cylinder
It is set to put in. Thereby, the winding diameter of the secondary pulley 28 can be moved to the maximum side early,
In addition, the winding diameter of the primary pulley 26 can be moved to the minimum side early, and the slack of the belt can be reliably removed.

[0032] On the other hand, from the step a8 of the main routine, step a 9 when the current gear position P, a N-range
And two who performs the low-speed control of FIG. 14 (b). Here, in step d3, it is determined whether or not the low speed control is currently being performed, that is, the previously set low speed control flag is on. If the low-speed control flag is not on, the process proceeds to step d6, and the same low-speed range determination value when the primary pulley rotation speed Wp is in the P, N range.
Is determined . When the control value falls below the control value , the low speed control flag is set, and the process proceeds to step d2. Steps d low speed control flag is on in step d 3
Proceeding to 4, clears the low-speed control flag in step d5 if the primary pulley rotation speed Wp low-speed range-size value or more, the process proceeds to the normal running mode.

[0033] When low-speed control flag is ON, it reaches to d 8 from step d 2. In this case, since the current gear position is in the P and N ranges, unnecessary supply of line pressure is prevented.
Shift shots such as reduction of implosion and shift from N to D
Control hydraulic pressure Ps to the secondary pulley to prevent
Is maintained at the minimum line pressure, and the process proceeds to step d9 . here
Calculates a set cycle S (see the primary pulley hydraulic pressure output cycle calculation map in FIG. 7) in accordance with an increase in the primary pulley rotation speed Wp, and sets a predetermined level of pulley control in accordance with the same cycle.
The hydraulic pressure Pp is intermittently inserted into the primary hydraulic cylinder.
It is set so as that.

As a result, while the current gear position is in the P, N range and there is no intention to start, unnecessary increase processing of the secondary pulley pulley control hydraulic pressure Ps is not performed, and the primary pulley hydraulic pressure Pp is intermittently charged. Oil dropout from the primary pulley 26 and slack of the belt can be reliably removed. FIG. 15 shows the control in the case where the start determination is made while the low-speed control flag is on as the start control in step a11 . For low speed control, the process proceeds to step e2, between the primary pulley rotation speed Wp does not exceed the start determination value (e.g. 500 rpm), the process proceeds to step e3 or e5 or e7, brake as a starting intention information of the driver Step e4, when it is detected that either the signal is off, the accelerator switch signal is on, or the engine torque Te exceeds a predetermined value .
The process proceeds to the execution control processing of e6 and e8 .

In this case, the rotation speed Wp of the primary pulley is
The process proceeds to step e9 exceeds origination advance determination value, the flow returns to the main routine clears the timer set flag. When the start control process shown in FIG. 16 starts, the process proceeds to step f3 as long as the timer set flag is not turned on. Here, the flag is turned on, and the process proceeds to step f4. If the timer set flag is turned on in step f1, the timer is started , and the process proceeds to step f4. In step f4, after the start determination,
Determines whether the elapsed constant time (e.g., 50 m sec).
If it is before a predetermined time elapses the process proceeds to step f7, the hydraulic pressure supplied to the primary cylinder to set the duty ratio of the maximum value, for example electrostatic solenoid valve control valve 23 to the corresponding 30%, prior to starting, the deviation pulley and the belt Is finally removed.

When a predetermined time has elapsed in step f4, the target primary pulley control oil pressure Pp1 in another current routine (for example, a normal control routine) is fetched, and the intermediate value ( for example, an oil pressure equivalent to a duty ratio of 55% ) is taken. Only during this time, the process proceeds to step f6, where the target primary pulley control hydraulic pressure for start control Pp2 is set to the above-mentioned intermediate value, and the oil amount in the primary cylinder 33 is maintained.
The electromagnetic control valve 23 is driven . The target primary pulley control pressure Pp1 is below the set intermediate value (de Yuti
When the rate exceeds 55%), the process returns to the main without setting the output value (Du value) to the electromagnetic control valve 23 in the start control process.
For this reason, the subsequent target primary pulley control hydraulic pressure Pp
1 is the target primary pulley control oil pressure P in another routine
Since p1 is adopted, it is possible to eliminate a sense of incongruity when the vehicle heads for normal traveling rather than starting at the time of starting.

[0037] After the end of the start control returns to the main routine, reached in step a12, enter the normal shift speed processing. As shown in FIG. 17, here, first, step g
The target primary pulley rotational speed Wpo and the actual primary pulley rotational speed Wp corresponding to the target gear ratio are fetched in 1, 2, and 3, and a deviation E (= Wpo-Wp) thereof is obtained, and the responsiveness is reduced as the engine rotational speed increases. The change gain K1 and the change gain K2 for increasing the responsiveness in accordance with the increase in the deviation between the actual value of the primary pulley and the target value are fetched. Step g3
Then, the basic shift speed Vi1 is calculated by multiplying the deviation E by the gains K1 and K2. Further, at step g4, the basic shift speed Vi1 is integrated, a deviation from the previous value is calculated, and the deviation is multiplied by a limiter for diffusion prevention.
The current integrated corrected shift speed ViI is obtained by multiplying / Z. Then, the basic shift speed Vi1 and the integrated corrected shift speed ViI are added to calculate the shift speed Vi. In step g5, a shift speed signal Du corresponding to the shift control oil pressure Pc capable of achieving the shift speed Vi is calculated. In step g6, the electromagnetic control valve 23 is driven by the shift speed signal Du. Thereby, the electromagnetic control valve regulates the shift control oil pressure Pc,
Transmission ratio control valve 54 which receives the transmission control oil pressure Pc is Pla
Supplying Imari pulley control pressure Pp to the cylinder hydraulic actuator of the primary pulley, switching the primary pulley at the target speed change rate, and thus to achieve the target speed ratio I.

[0038]

As described above, according to the first aspect of the present invention, when the low speed range is determined, the predetermined hydraulic pressure is intermittently supplied to the primary hydraulic actuator, and the hydraulic pressure is applied to the primary hydraulic actuator when the vehicle starts moving after stopping. Can be maintained, even if the line pressure corrected for pressure is supplied to the secondary hydraulic actuator for a predetermined time after stopping, the gear ratio will be changed to the full low state with the start even if the return to the full low state is not performed. When returning to the primary hydraulic actuator, the primary pulley is suppressed from suddenly moving to the full low state due to the flow resistance acting when the hydraulic pressure charged in the primary hydraulic actuator is discharged, and is gradually returned to the full low state. As a result, damage caused by slippage between the belt and the pulley at the time of starting can be reliably prevented. In addition, since the supply of the predetermined hydraulic pressure to the primary hydraulic actuator is performed intermittently, the winding diameter of the primary pulley is reliably prevented from moving to the upshift side. Drive loss is suppressed. Moreover,
When the stop state is detected in the low-speed range and the stop state is detected, the line pressure corrected for pressure is supplied to the secondary hydraulic actuator for a predetermined time from the stop state. The hanging diameter is moved to the maximum side early and can be returned to the full-low side in a short time after the stop, and the slack of the belt is reliably removed, which is caused by slipping between the belt and the pulley at the time of starting. Damage can be prevented. Furthermore,
By setting the supply of the pressure-increasing corrected line pressure to the secondary hydraulic actuator for a predetermined time, the drive loss due to the oil pump is suppressed, and the deterioration of fuel efficiency is suppressed.

According to the second aspect of the present invention, when a start request is detected after it is determined that the vehicle is in the low speed range, the maximum hydraulic pressure is supplied to the primary hydraulic actuator for a predetermined period of time. Even at times, an abrupt shift to the full low side due to an increase in line pressure due to an increase in input load is suppressed, and occurrence of belt slip is prevented. Further, after the lapse of the predetermined time, the predetermined hydraulic pressure lower than the maximum hydraulic pressure is supplied to the primary hydraulic actuator, so that the speed is gradually shifted to the full low side due to the flow resistance caused by the discharge of the oil, and the speed is changed between the belt and the pulley. It is possible to prevent damage caused by slippage of the vehicle, and to suppress a feeling of strangeness at the time of shifting when starting.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a vehicle power transmission system including a shift control device of a continuously variable transmission as one embodiment of the present invention.

FIG. 2 is a functional block diagram of an electronic control unit in the apparatus of FIG.

FIG. 3 is a hydraulic circuit diagram of the continuously variable transmission used by the continuously variable transmission in the apparatus of FIG.

FIG. 4 is a sectional view of a main part of a continuously variable transmission in the apparatus of FIG. 1;

FIG. 5 is a characteristic diagram of a target primary pulley rotation speed calculation map adopted by the electronic control device in the device of FIG. 1;

FIG. 6 is a characteristic diagram of a target hydraulic pressure calculation map of a secondary cylinder employed by an electronic control device in the device of FIG. 1;

FIG. 7 is a characteristic diagram of a primary cylinder hydraulic pressure output cycle calculation map employed by the electronic control unit in the apparatus of FIG. 1;

FIG. 8 is a characteristic diagram of an intake air amount calculation map adopted by an electronic control unit in the apparatus of FIG. 1;

FIG. 9 is a characteristic diagram of a torque calculation map adopted by an electronic control unit in the apparatus of FIG.

FIG. 10 is a flowchart of a shift control main routine employed by the electronic control unit in the apparatus of FIG.

FIG. 11 is a flowchart of a brake control routine employed by the electronic control unit in the apparatus of FIG. 1;

FIG. 12 is a flowchart of a brake control routine employed by the electronic control unit in the apparatus of FIG. 1;

FIG. 13 is a flowchart of a low-speed control (a) routine employed by the electronic control unit in the apparatus shown in FIG. 1;

FIG. 14 is a flowchart of a low-speed control (b) routine employed by the electronic control unit in the apparatus of FIG. 1;

FIG. 15 is a flowchart of a start control routine adopted by the electronic control unit in the apparatus of FIG. 1;

FIG. 16 is a flowchart of a start control routine employed by the electronic control unit in the apparatus shown in FIG. 1;

FIG. 17 is a flowchart of a shift speed control routine employed by the electronic control unit in the apparatus of FIG.

[Explanation of symbols]

12 throttle opening sensor 13 accelerator opening sensor 20 continuously variable transmission 21 CVT ECU 23 electromagnetic control valve 26 primary pulley 27 drive belt 28 secondary pulley 33 primary cylinder 34 secondary cylinder 40 electromagnetic control valve 45 hydraulic actuator 46 hydraulic actuator 48 regulator valve 54 Transmission oil pressure control valve 70 Line pressure adjustment valve 71 Transmission control valve Ws Secondary pulley rotation speed Wp Primary pulley rotation speed Wpo Target primary pulley rotation speed Wp1 Target primary pulley rotation speed Wp2 Target primary pulley rotation speed Vi Target shift speed S period

Claims (2)

(57) [Claims] A primary pulley connected to the engine; a secondary pulley connected to the drive shaft; an endless belt stretched between the two pulleys; and a winding diameter of the endless belt on the primary pulley. A shift control device for a continuously variable transmission for a vehicle, comprising: a primary hydraulic actuator to be changed; and a secondary hydraulic actuator to change a winding diameter of the endless belt on the secondary pulley side. Primary pulley control means for controlling the hydraulic pressure supplied to the primary hydraulic actuator according to the target primary pulley rotation speed, and the line pressure supplied to the secondary hydraulic actuator according to the operating state of the vehicle. Line pressure setting means to be set A low-speed range determining means for determining whether or not the rotation speed of the pulley pulley is lower than a predetermined low-speed range determining value; a line pressure correcting means for increasing and correcting the line pressure set by the line pressure setting means; A control oil pressure intermittent output setting means for storing a cycle proportional to an increase in the number of revolutions, and setting a predetermined control oil pressure to be intermittently supplied to the primary hydraulic actuator at the same cycle; when it is determined that the frequency, the upper
Predetermined control set by the control oil pressure intermittent output setting means
Hydraulic pressure is supplied to the primary hydraulic actuator
Control the primary pulley control means
The low-speed range determining means determines that the vehicle is in the low-speed range and
During the predetermined time after the stop state is detected, the line pressure
The line pressure corrected by the means
Line pressure setting to be supplied to pressure actuator
And a shift control means for controlling the shift means. A primary pulley connected to the engine side, a secondary pulley connected to the drive shaft side, an endless belt stretched between the two pulleys, and a winding diameter of the endless belt on the primary pulley side. A shift control device for a continuously variable transmission for a vehicle, comprising: a primary hydraulic actuator to be changed; and a secondary hydraulic actuator to change a winding diameter of the endless belt on the secondary pulley side. Primary pulley control means for controlling the hydraulic pressure supplied to the primary hydraulic actuator according to the target primary pulley rotation speed, and the line pressure supplied to the secondary hydraulic actuator according to the operating state of the vehicle. Line pressure setting means to be set A low-speed range determining means for determining whether or not the rotation speed of the immersion pulley is lower than a predetermined low-speed range determination value; and a start request for determining whether or not a start request has been made after the low-speed range determining means has determined that the low-speed range has been determined. Determining means, when a start request is detected by the start request determining means, a maximum hydraulic pressure is supplied to the primary hydraulic actuator for a predetermined time and a predetermined hydraulic pressure lower than the maximum hydraulic pressure is supplied to the primary hydraulic actuator after the predetermined time has elapsed. A shift control device for controlling the primary pulley control device so that hydraulic pressure is supplied, the shift control device for a continuously variable transmission.