JP6840445B2 - Shift control device for belt-type continuously variable transmission - Google Patents

Description

The present invention relates to a speed change control device for a belt-type continuously variable transmission capable of steplessly changing the gear ratio when transmitting power between pulleys by a belt.

Conventionally, Patent Document 1 describes that in the shift pressure control of a belt-type stepless transmission, the difference between the target shift ratio and the actual shift ratio is feedback-controlled, while the variable pulley is based on a predetermined shift difference thrust characteristic. A technique is disclosed in which the thrust is feed-forward controlled and the learning control of the shift difference thrust characteristic related to the feed-forward control is performed based on the control amount of the feedback control in the shift pressure control performed in the past. Further, it is disclosed that feedforward control according to the shift difference thrust characteristic is performed for each unit by changing the shift difference thrust characteristic using the feedback control amount at the time of shifting as a learning value.

Japanese Unexamined Patent Publication No. 2012-241799

However, since the characteristics of the continuously variable transmission change every time the gear is changed, or due to the difference in the number of revolutions and the difference in the oil pressure, the learning control of the feedforward control is finally carried out at the stage when the feedback control amount is accumulated. It took time for the control to stabilize, and it was difficult to achieve the target driving performance.
The present invention has been made with attention to the above problems, and an object of the present invention is to provide a speed change control device for a belt-type continuously variable transmission capable of achieving stable speed change control.

In order to achieve the above object, the speed change control device for the belt-type continuously variable transmission of the present invention includes a belt-type continuously variable transmission including a primary pulley, a secondary pulley, and a belt wound around both pulleys.
The balance thrust ratio, which is the ratio of the pulley hydraulic pressure supplied to the hydraulic chamber of each pulley, is calculated based on the input torque to the belt-type continuously variable transmission and the target gear ratio, and the reference pulley oil pressure based on the balance thrust ratio is calculated. A shift control means that calculates the feedback oil pressure by feedback control according to the difference between the target gear ratio and the actual gear ratio, and performs shift control based on the reference pulley oil pressure and the feedback hydraulic pressure.
In the shift control device of the belt type continuously variable transmission equipped with
When the target gear ratio is changed to the second target gear ratio, the shift control means is preset to the reference pulley oil pressure, and the value corresponding to the rotation speed of the secondary pulley at the second target gear ratio is set in advance. The higher the value, the larger the feed forward oil pressure is added.

Therefore, even if the characteristics of the belt-type continuously variable transmission change according to the operating state, stable shift control can be achieved while ensuring responsiveness.

It is a system diagram which shows the shift control device of the belt type continuously variable transmission of Example 1. FIG. It is a control block diagram which shows the shift control process of Example 1. FIG. It is a map which shows the characteristic of the secondary oil pressure with respect to the required torque of Example 1. It is a torque ratio-thrust ratio map used for the shift control of the belt type continuously variable transmission of Example 1. It is a map which shows the secondary rotation speed compensation amount HNsec based on the secondary rotation speed of Example 1. It is a map which shows the secondary pressure compensation amount HPsec based on the secondary pressure of Example 1. It is a map which shows the gear ratio compensation amount HGb based on the actual gear ratio of Example 1. It is a flowchart which shows the integral component control process performed by the integrator of Example 1. FIG. It is a time chart which shows the relationship between the compensation amount H and the deviation ΔG at the time of shift control of Example 1. FIG.

FIG. 1 is a system diagram showing a shift control device for the belt-type continuously variable transmission according to the first embodiment. The vehicle of the first embodiment has an engine 1 which is an internal combustion engine and a belt-type continuously variable transmission, and transmits a driving force to the drive wheels 8 via a differential gear 7. The belt-type continuously variable transmission includes a transmission input shaft 2 connected to the crankshaft of the engine 1, a primary pulley 3 that rotates integrally with the transmission input shaft 2, and a secondary that rotates integrally with the transmission output shaft 6. It has a pulley 5 and a belt 4 that is wound between the primary pulley 3 and the secondary pulley 5 to transmit power.

The primary pulley 3 has a fixed sheave 3a formed integrally with the transmission input shaft 2 and a movable sheave 3b that can move on the transmission shaft 2. The movable sheave 3b is provided with a primary hydraulic chamber 3b1, and a pressing force is generated between the fixed sheave 3a and the movable sheave 3b by the primary hydraulic Ppri supplied to the primary hydraulic chamber 3b1 to hold the belt 4. Similarly, the secondary pulley 5 has a fixed sheave 5a formed integrally with the transmission output shaft 6 and a movable sheave 5b that can move on the axis of the transmission output shaft 6. A secondary hydraulic chamber 5b1 is provided in the movable sheave 5b, and a pressing force is generated between the fixed sheave 5a and the movable sheave 5b by the secondary hydraulic pressure Psec supplied to the secondary hydraulic chamber 5b1 to sandwich the belt 4.

The engine controller 10 controls the engine speed and the engine torque by controlling the operating state (fuel injection amount, ignition timing, etc.) of the engine 1. Further, in the engine controller 10, the required torque calculation for calculating the driver's required torque TD based on the accelerator opening signal APO detected by the accelerator opening sensor 21 and the actual vehicle speed signal VSP detected by the vehicle speed sensor 22. It has a unit 10a and an engine torque calculation unit 10b that calculates the engine torque TENG transmitted to the transmission input shaft 2.
In the transmission controller 20, the primary oil pressure Ppri and the secondary oil pressure Psec are calculated according to the traveling state, and a control signal is output to the control valve unit 30. Details of the transmission controller 20 will be described later.
The control valve unit 30 uses an oil pump 9 chain-driven on the transmission input shaft 2 as a hydraulic source, and regulates each oil pressure based on a control signal transmitted from the transmission controller 20. Then, the primary hydraulic Ppri and the secondary hydraulic Psec are supplied to the primary hydraulic chamber 3b1 and the secondary hydraulic chamber 5b1, respectively, and the shift control is executed.

FIG. 2 is a control block diagram showing a shift control process in the transmission controller of the first embodiment. The target gear ratio calculation unit 201 calculates the target gear ratio Ga based on the accelerator opening signal APO and the target vehicle speed signal VSP. This target gear ratio Ga is performed based on the gear shifting characteristics set in advance so that the engine 1 achieves the optimum fuel consumption. Further, when the shift lever or the shift switch requests the control of the fixed gear ratio, the fixed gear ratio control for changing the gear ratio step by step is performed. The torque ratio calculation unit 202 calculates the torque ratio Qt, which is the ratio of the engine torque TENG to the torque Tmax (see FIG. 3) according to the secondary torque set based on the required torque TD.

The actual gear ratio calculation unit 203 reads the actual primary rotation speed Npri detected by the primary rotation speed sensor 23 and the actual secondary rotation speed Nsec detected by the secondary rotation speed sensor 24, and calculates the actual gear ratio Gb.

The gear ratio feedforward control unit 204 calculates the feedforward oil pressure Pff based on the target gear ratio Ga and outputs it to the addition unit 207 described later.

The gear ratio feedback control unit 205 includes a deviation calculation unit 205a, a proportional device 205b, a differentiator 205c, an integrator 205d, and an addition unit 205e. The deviation calculation unit 205a calculates the deviation ΔG between the target gear ratio Ga and the actual gear ratio Gb. In the proportional device 205b, the detected deviation ΔG is multiplied by the proportional gain to calculate the proportional component. In the differentiator 205c, the detected deviation ΔG is differentiated, the differential gain is multiplied, and the differential component is calculated. In the integrator 205d, the detected deviation ΔG is multiplied by the integration gain and integrated to calculate the integration component Ix. As a result, the oil pressure to be added to or subtracted from the primary oil pressure Ppri and the secondary oil pressure Psec by PID control (hereinafter referred to as feedback oil pressure Pfb) is output. In the addition unit 205e, the components output from the proportional device 205b, the differentiator 205c, and the integrator 205d are added and output as the feedback pressure Pfb. The details of the integrator 205d will be described later.

The balance thrust control unit 206 calculates the balance thrust ratio from a preset map based on the target gear ratio Ga and the torque ratio Qt calculated by the torque ratio calculation unit 202. FIG. 4 is a torque ratio-balance thrust ratio map used for shift control of the belt-type continuously variable transmission according to the first embodiment. A characteristic is selected based on the target gear ratio Ga, and the balance thrust ratio Qf is calculated from the selected characteristic and the torque ratio Qt. Next, the reference secondary oil pressure Psecb, which is the reference oil pressure, is calculated from the map showing the secondary oil pressure characteristics in FIG. Calculate Pprib. Hereinafter, the reference secondary oil pressure Psecb and the reference primary oil pressure Pprib are collectively referred to as the reference pulley oil pressure Pb.

In the balance compensator 208, the actual gear ratio Gb, the actual secondary oil pressure Psec, and the secondary rotation speed Nsec are input, and the belt-type continuously variable transmission is displayed from a preset map according to the operating state of each parameter. Calculates the feed-forward compensating oil pressure Pbf (hereinafter referred to as the compensating amount H) for balancing.

FIG. 5 is a map showing the secondary rotation speed compensation amount HNsec based on the actual secondary rotation speed of the first embodiment. The larger the actual secondary rotation speed Nsec, the larger the secondary rotation speed compensation amount HNsec is set.
FIG. 6 is a map showing the secondary pressure compensation amount HPsec based on the secondary pressure of the first embodiment. The smaller the actual secondary flood control Psec, the more negative compensation is output, and 0 is output above the predetermined flood control.
FIG. 7 is a map showing the gear ratio compensation amount HGb based on the actual gear ratio of the first embodiment. When the actual gear ratio Gb is lower than the predetermined gear ratio, a negative compensation amount is output, and when the actual gear ratio Gb is higher than the predetermined gear ratio, a positive compensation amount is output.

The maps shown in FIGS. 5, 6 and 7 are set based on the results of analysis by extracting correlated factors from tens of thousands of measurement data. It was found that this factor is expressed in the form of the amount of hydraulic pressure correction, not as the correction gain of the balance thrust ratio. The belt-type continuously variable transmission has a map for calculating the balanced thrust ratio, but the characteristic that the balanced thrust changes due to changes in other parameters that cannot be shown on the map for calculating the balanced thrust ratio. Has. Conventionally, these indescribable characteristic changes have been adjusted by gear ratio feedback control. Here, for example, when introducing a control that changes the gear ratio step by step, or when the gear ratio is significantly changed due to kickdown, responsiveness becomes a problem. If the feedback gain is set large in order to improve the responsiveness, it may cause instability such as divergence of control. Further, if the feedback gain is suppressed in order to ensure robustness, it takes time to reach the target gear ratio. Therefore, in the first embodiment, when the target gear ratio is changed, the compensation amount due to the newly discovered three parameters is added in advance to reduce the compensation amount by the feedback control and secure the robustness. At the same time, we decided to ensure responsiveness.

The multiplication unit 207 adds the reference pulley oil pressure Pb, the feedback oil pressure Pfb, and the compensation amount H, and outputs the primary oil pressure command value and the secondary oil pressure command value (hereinafter, collectively referred to as the pulley oil pressure command value). To do.

Here, the details of the integrator 205d of the gear ratio feedback control unit 205 will be described. In the integrator 205d of the first embodiment, the change speed ΔGb of the actual gear ratio Gb and the integral specified value Ia that estimates the range of the variation of the balance deviation are input, and the integral component is reset based on these two values. Make a judgment.
FIG. 8 is a flowchart showing the integral component control process performed by the integrator of the first embodiment.
In step S1, it is determined whether or not the change speed ΔGb is a predetermined value g1 or more indicating a preset sudden shift, and if g1 or more is determined to be a sudden shift, the process proceeds to step S2, otherwise the flow ends. Then, the usual integral integral is calculated.
In step S2, it is determined whether or not the absolute value | Ix | of the integral component is equal to or less than the integral specified value Ia, and if it is less than or equal to Ia, a large steady deviation such as the hydraulic offset value does not occur, that is, only the balance deviation. Is determined to occur and the process proceeds to step S3. If it is larger than Ia, it is determined that a large steady-state deviation has occurred, and this flow is terminated to calculate the normal integral component.
In step S3, the integral component Ix is reset.

The details of the control in the integrator 205d will be described. In the first embodiment, since the compensation amount H based on the three parameters is given, the deviation ΔG to be compensated by the feedback control is less likely to occur. However, when shifting is continuous, it is assumed that the integrator component Ix is accumulated in the integrator 205d in the process of shifting from the previous gear ratio to the next gear ratio. For example, when a downshift is executed in a state where a positive value is accumulated as the integral component Ix due to the upshift, a negative value is preferable as the integral component Ix. However, if a large positive value is set for the integral component Ix, it takes time to subtract the integral component Ix, which may reduce the responsiveness. Therefore, in the first embodiment, when there is a sudden shift request, the responsiveness can be ensured by resetting the integral component Ix to 0.

FIG. 9 is a time chart showing the relationship between the compensation amount H and the deviation ΔG at the time of shift control in the first embodiment. When the deviation ΔG is settled, the compensation amount H obtained by adding HNsec, HPsec, and HGb is the value of H1. When the downshift request is output at time t1, the deviation ΔG increases. At this time, since the change in the characteristics of the belt-type continuously variable transmission due to the change in the operating point has not been taken into consideration in the past, the gear ratio feedback control has to be used. On the other hand, in the first embodiment, since the compensation amount H is changed to H2, the portion corresponding to the change in the characteristics of the belt-type continuously variable transmission can be compensated in advance, and the other portion can be fed back to the gear ratio. Since it is only necessary to control the speed, it is possible to shift gears with high responsiveness.

At time t2, when an upshift is requested this time, the deviation ΔG becomes a negative value, and the required integral component Ix also becomes a negative value. At this time, since the compensation amount H is changed to H3 and the integral component Ix is reset to 0 as in the time t1, the deviation ΔG can be eliminated immediately. Since the same applies after time t3, the description thereof will be omitted.

As described above, resetting the integral component Ix is effective in ensuring responsiveness if a compensation amount for balancing the belt-type continuously variable transmission at a desired gear ratio is given. However, when there is a large steady-state deviation that is not a balance deviation, such as an offset in the pulley oil pressure, the integral component Ix may be accumulated until it reaches a large value even if the target gear ratio is constant. is there. If the large integral component Ix accumulated at the time of sudden shift request is reset at once, the offset amount of the pulley oil pressure cannot be compensated, and it becomes difficult to secure the stability of shift control. Therefore, if the integral component Ix is equal to or greater than the predetermined value Ia estimated by the range of the variation of the balance deviation, it is considered that the integral component Ix is constantly accumulated due to a large disturbance that is not the balance deviation, and the reset of the integral component Ix is prohibited. And said. As a result, the stability of shift control can be further ensured.

As described above, in Example 1, the effects listed below can be obtained.
(1) A belt-type continuously variable transmission equipped with a primary pulley 3, a secondary pulley 5, and a belt 4 wound around both pulleys, and an engine torque TENG (input torque to the belt-type continuously variable transmission). The thrust ratio, which is the ratio of the pulley oil pressure supplied to the hydraulic chamber of each pulley, is calculated based on the target gear ratio Ga, the reference pulley oil pressure is calculated based on the thrust ratio, and the target gear ratio Ga and the actual gear ratio Gb are calculated. A belt-type continuously variable transmission equipped with a transmission controller 20 (shift control means) that calculates the feedback oil pressure by feedback control according to the difference between the two and controls the shift based on the reference pulley hydraulic pressure and the feedback hydraulic pressure. In the shift control device, when changing the target gear ratio to the second target gear ratio, the transmission controller 20 is preset in the reference pulley oil pressure and compensates according to the operating state at the second target gear ratio Ga. Add the amount H (feed forward oil pressure for the continuously variable transmission to balance).
Therefore, even if the characteristics of the belt-type continuously variable transmission change according to the operating state, stable shift control can be achieved while ensuring responsiveness.

(2) The actual secondary rotation speed compensation amount HNsec is a larger value as the secondary rotation speed Nsec (value equivalent to the rotation speed of the secondary pulley) is higher. Therefore, even if the characteristics of the balance thrust ratio of the belt-type continuously variable transmission change according to the secondary rotation speed Nsec, stable shift control can be achieved by applying an appropriate compensation amount HNsec. Not limited to the actual secondary rotation speed Nsec, the target secondary rotation speed Nsec *, the actual vehicle speed VSP, the target vehicle speed VSP *, the target primary rotation speed Npri *, and the actual primary rotation speed Npri may be used.
(3) The secondary oil pressure compensation amount HPsec is a negative value whose absolute value increases as the secondary oil pressure Psec (value equivalent to the oil pressure of the secondary pulley) decreases. Therefore, even if the characteristics of the balance thrust ratio of the belt-type continuously variable transmission change according to the secondary hydraulic pressure Psec, stable shift control can be achieved by giving an appropriate compensation amount HPsec. Not limited to the actual secondary oil pressure Psec, the target secondary oil pressure Psec *, the actual engine torque TENG, the target engine torque TENG *, the target primary pressure Ppri *, and the actual primary oil pressure Ppri may be used.
(4) The gear ratio hydraulic compensation amount HGb is a negative compensation amount HGb when the actual gear ratio Gb is lower than the predetermined gear ratio, and is a positive compensation amount HGb when the actual gear ratio Gb is higher than the predetermined gear ratio. Therefore, even if the characteristics of the balance thrust ratio of the belt-type continuously variable transmission change according to the actual gear ratio Gb, stable shift control can be achieved by applying an appropriate compensation amount HGb. The target gear ratio Ga may be used instead of the actual gear ratio Gb.

(5) When the change speed ΔGb of the actual gear ratio Gb is equal to or greater than the predetermined value g1 indicating a sudden shift, the integral component Ix of the feedback control is reset. Therefore, it is possible to further secure the responsiveness and achieve stable shift control. The target gear ratio Ga may be used instead of the actual gear ratio Gb.

(6) When the absolute value | Ix | of the integral integration of the feedback control is equal to or greater than the predetermined value Ia indicating the range of the variation of the balance deviation, the reset of the integral component Ix is prohibited. Therefore, it is possible to further secure the responsiveness and achieve stable shift control. The target gear ratio Ga may be used instead of the actual gear ratio Gb, and the upper and lower limits of the predetermined value Ia representing the estimated value of the balance deviation may be set to different values. .. That is, when the integral component of the feedback control is outside the predetermined range representing the range of the variation of the balance deviation, the reset of the integral component of the feedback control is prohibited.

(Other Examples)
Although the description has been described above based on the first embodiment, the present invention includes not only the above-described embodiment but also other configurations. Although the example of calculating the balance thrust ratio according to the torque ratio is shown in the first embodiment, the balance thrust ratio may be calculated according to the target gear ratio and the input torque.

1 engine
2 Transmission input shaft
3 Primary pulley
3a fixed sheave
3b movable sheave
3b1 Primary hydraulic chamber
4 belt
5 Secondary pulley
5a fixed sheave
5b movable sheave
5b1 Secondary hydraulic chamber
10 engine controller
20 transmission controller
30 Control valve unit
205 Gear ratio feedback control unit
208 Balance Compensator

Claims (5)

A belt-type continuously variable transmission equipped with a primary pulley, a secondary pulley, and a belt wound around both pulleys.
The balance thrust ratio, which is the ratio of the pulley hydraulic pressure supplied to the hydraulic chamber of each pulley, is calculated based on the input torque to the belt-type continuously variable transmission and the target gear ratio, and the reference pulley oil pressure based on the balance thrust ratio is calculated. A shift control means that calculates the feedback oil pressure by feedback control according to the difference between the target gear ratio and the actual gear ratio, and performs shift control based on the reference pulley oil pressure and the feedback hydraulic pressure.
In the shift control device of the belt type continuously variable transmission equipped with
When the target gear ratio is changed to the second target gear ratio, the shift control means is preset to the reference pulley oil pressure, and the value corresponding to the rotation speed of the secondary pulley at the second target gear ratio is set in advance. A speed change control device for a belt-type continuously variable transmission, characterized in that the higher the value, the larger the feed forward oil pressure is added. A belt-type continuously variable transmission equipped with a primary pulley, a secondary pulley, and a belt wound around both pulleys.
The balance thrust ratio, which is the ratio of the pulley hydraulic pressure supplied to the hydraulic chamber of each pulley, is calculated based on the input torque to the belt-type continuously variable transmission and the target gear ratio, and the reference pulley oil pressure based on the balance thrust ratio is calculated. A shift control means that calculates the feedback oil pressure by feedback control according to the difference between the target gear ratio and the actual gear ratio, and performs shift control based on the reference pulley oil pressure and the feedback hydraulic pressure.
In the shift control device of the belt type continuously variable transmission equipped with
When the target gear ratio is changed to the second target gear ratio, the shift control means is preset to the reference pulley oil pressure, and the oil pressure equivalent value of the secondary pulley at the second target gear ratio is small. A speed change control device for a belt-type continuously variable transmission that is characterized by adding a moderately large feed forward oil pressure. A belt-type continuously variable transmission equipped with a primary pulley, a secondary pulley, and a belt wound around both pulleys.
The balance thrust ratio, which is the ratio of the pulley hydraulic pressure supplied to the hydraulic chamber of each pulley, is calculated based on the input torque to the belt-type continuously variable transmission and the target gear ratio, and the reference pulley oil pressure based on the balance thrust ratio is calculated. A shift control means that calculates the feedback oil pressure by feedback control according to the difference between the target gear ratio and the actual gear ratio, and performs shift control based on the reference pulley oil pressure and the feedback hydraulic pressure.
In the shift control device of the belt type continuously variable transmission equipped with
When the target gear ratio is changed to the second target gear ratio, the shift control means is preset in the reference pulley oil pressure, and when the second target gear ratio is lower than the predetermined gear ratio, the shift control means is set in advance. A speed change control device for a belt-type continuously variable transmission, characterized in that a negative feed-forward oil pressure is added to a positive feed-forward oil pressure when the speed is higher than the predetermined gear ratio. In the speed change control device for the belt-type continuously variable transmission according to any one of claims 1 to 3.
A shift control device for a belt-type continuously variable transmission, characterized in that the integral component of the feedback control is reset when the change speed of the gear ratio is equal to or greater than a predetermined value representing a sudden shift. In the speed change control device for the belt-type continuously variable transmission according to any one of claims 1 to 4.
A speed change control device for a belt-type continuously variable transmission, characterized in that resetting of the integrated component of the feedback control is prohibited when the integrated component of the feedback control is out of a predetermined range representing an estimated value of the deviation of the balance.

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