KR20240021408A - Method for Variable Gear Ratio Control Using Turbine Speed of Continuously Variable Transmission - Google Patents

Abstract

The turbine speed type variable gear ratio control method of the continuously variable transmission (1) of the present invention is based on the lever position, torque converter clutch, accelerator pedal APS, vehicle speed, and turbine-engine speed difference detected in the TCU (Transmission Control Unit) (10). For Lever position = D (Drive), torque converter clutch = Open, accelerator pedal APS = 0, lower limit set value <vehicle speed <upper limit set value, and turbine-engine speed difference > set value are met as conditions, and the above conditions are met. When satisfied, the turbine speed of the torque converter 50 is adjusted to the engine speed of the engine 100 by adjusting the turbine speed of the torque converter 50 to the engine speed of the engine 100 with the setting value applied to the target gear ratio to reduce the pulley gear ratio. In particular, the turbine speed control that matches the engine speed is implemented by changing the CVT target pulley gear ratio, which significantly improves the engine and turbine crossing feel when tipping in at low speeds.

Description

Method for variable gear ratio control using turbine speed of continuously variable transmission {Method for Variable Gear Ratio Control Using Turbine Speed of Continuously Variable Transmission}

The present invention relates to variable gear ratio control of a continuously variable transmission, and in particular, to a turbine speed type variable gear ratio control method that controls the turbine speed in a tip-in situation due to pressing the accelerator pedal at low speed.

In general, a continuously variable transmission (CVT) for automobiles is a type of transmission in which continuous, continuous shifting is performed without a specific shift range between each shift stage.

For example, among the continuously variable transmissions, the belt-type CVT uses two pulleys tied together with a belt to change the contact radius of the belt by changing the axial gap by applying hydraulic pressure in the axial direction of the pulley, and through this, a transmission ratio suitable for low/high speeds and Shifting is implemented by varying the driving force.

In particular, the belt-type CVT requires improvement in engine and turbine crossing feel. This is because at low speeds, when the torque convertor of the CVT is open, the engine and transmission turbine This is because when you step on the accelerator pedal while there is a speed difference, the shifting sensation at the starting point of the shift deteriorates due to crossing caused by the difference between the engine speed and the transmission turbine speed.

For this purpose, the belt-type CVT performs engine speed-type variable gear ratio control, and the engine speed-type variable gear ratio control controls the turbine speed to match the engine speed when the accelerator pedal is pressed in the speed difference between the engine and transmission turbine, and these engines Speed control reduces engine and turbine crossing feel.

Japanese registered patent JP 3475678 B (2003.09.26)

However, the engine speed variable gear ratio control of the belt-type CVT requires increasing the idle speed of the engine in the process of controlling the turbine speed to match the engine speed, and this increase in engine idle speed is due to the engine-turbine crossover feeling (Engine & Turbine). By limiting the reduction of the (crossing feel), the driver has no choice but to feel that the vehicle is moving forward.

Accordingly, taking the above into account, the present invention matches the turbine speed to the engine speed when shifting, and in particular, the turbine speed control adjusted to the engine speed is implemented by changing the CVT target pulley gear ratio to achieve tip-in ( The purpose is to provide a turbine speed type variable gear ratio control method for a continuously variable transmission that significantly improves the engine-turbine crossing feel (Tip in).

The turbine speed type variable gear ratio control method of the present invention to achieve the above object applies the pulley gear ratio setting value of the continuously variable transmission by satisfying the conditions of the detected shift information, and controls the turbine speed of the torque converter to the setting value. It is characterized by matching the engine speed of the engine.

In a preferred embodiment, the pulley gear ratio setting reduces the turbine speed.

In a preferred embodiment, the shift information is the lever position and the torque converter clutch, and the condition is met when the lever position is D and the torque converter clutch is not engaged.

In a preferred embodiment, the shift information is the lever position, torque converter clutch, and accelerator pedal APS, and the conditions are met when the lever position is D, the torque converter clutch is not fastened, and the accelerator pedal is not depressed. am.

In a preferred embodiment, the shift information is the lever position, torque converter clutch, accelerator pedal APS, and vehicle speed, and the conditions are met when the lever position is D, the torque converter clutch is not fastened, and the accelerator pedal is depressed. It is not turned on, and the vehicle speed is between the lower limit and upper limit set speed.

In a preferred embodiment, the shift information is the lever position, torque converter clutch, accelerator pedal APS, vehicle speed, and turbine-engine speed difference, and the conditions are met when the lever position is D, the torque converter clutch is in an unfastened state, The accelerator pedal is not depressed, the vehicle speed is between the lower limit and the upper limit set speed, and the turbine-engine speed difference is greater than the speed difference set value.

In a preferred embodiment, the turbine-engine speed difference is the turbine speed minus the engine speed, and the speed difference set value is 150 rpm.

In addition, the turbine speed type variable gear ratio control method of the present invention to achieve the above object includes the steps of detecting a plurality of lever position, torque converter clutch, accelerator pedal APS, vehicle speed, and turbine-engine speed difference as shift information, A shift entry condition confirmation step of determining that the driving position state of the lever position (D), the torque converter clutch is not engaged (Open), and the accelerator pedal APS is not detected (APS = 0), and the vehicle speed is lower than the lower limit. Confirming the CVT variable gear ratio control condition is between a set value and an upper limit set value and determining that the turbine-engine speed difference is greater than the speed difference set value, applying a set value for reducing the pulley gear ratio of the continuously variable transmission to the target gear ratio, and reducing the turbine speed to the set value so that the turbine speed of the torque converter matches the engine speed of the engine.

In a preferred embodiment, the accelerator pedal APS is detected before the turbine speed decreases, thereby confirming that the accelerator pedal is depressed.

In a preferred embodiment, the reduction control of the turbine speed is stopped when the turbine speed matches the engine speed.

In order to achieve the above object, the continuously variable transmission of the present invention includes a data detector that detects a plurality of lever position, torque converter clutch, accelerator pedal APS, vehicle speed, and turbine-engine speed difference as shift information; And for each of the lever position, the torque converter clutch, the accelerator pedal APS, the vehicle speed, and the turbine-engine speed difference, lever position = D (Drive), torque converter clutch = Open, accelerator pedal APS = 0, lower limit. The set value <vehicle speed <upper limit set value, and turbine-engine speed difference> is set to meet the conditions, and when the above conditions are met, the turbine speed of the torque converter is set to the set value applied to the target gear ratio to reduce the pulley gear ratio of the engine. It is characterized by including a TCU that adjusts the engine speed.

In a preferred embodiment, the data detector is linked to a sensor signal, and the sensor signal includes an accelerator pedal sensor for detecting APS, a vehicle speed sensor for detecting vehicle speed, a turbine sensor for detecting turbine speed, and an engine sensor for detecting engine speed. and a torque converter sensor that detects the torque converter clutch operating state.

In a preferred embodiment, the TCU is linked to a gear ratio map, and the gear ratio map outputs the target gear ratio to the TCU when the accelerator pedal is depressed based on accelerator pedal APS information.

The variable gear ratio control implemented in the continuously variable transmission of the present invention implements the following actions and effects.

First, tip in control can be performed at low speeds using the turbine speed as the control variable among the turbine speed and engine speed. Second, by adjusting the turbine speed to the engine speed, the increase in engine idle speed that previously occurred is prevented. Third, the engine and turbine crossing feel is greatly improved when tipping in at low speeds through turbine speed control. Fourth, the shift feel and tip in feel are improved by improving the engine-turbine crossing feel at the starting point of shifting, thereby improving vehicle marketability by preventing the driver from feeling that the vehicle is moving forward. Fifth, turbine speed control is implemented by changing the CVT target pulley gear ratio, making it suitable for belt-type CVT.

Figure 1 is a flow chart of a turbine speed type variable gear ratio control method of a continuously variable transmission according to the present invention, Figure 2 is an example of a continuously variable transmission according to the present invention, and Figure 3 is a low-speed tip-in engine-turbine intersection feeling ( This is an example of the condition of Engine & Turbine Crossing Feel.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached illustration drawings. These embodiments are examples and may be implemented in various different forms by those skilled in the art to which the present invention pertains, so they are described herein. It is not limited to the embodiment.

Referring to FIG. 1, the variable gear ratio control method implemented in a continuously variable transmission is that when the CVT variable gear ratio control condition is confirmed (S30) in the state of shift entry condition confirmation (S20) after shift information detection (S10), the pulley gear ratio is then reduced. After setting the value (S40), target pulley gear ratio control (S60) is performed in the state of accelerator pedal operation confirmation (S50). In this case, the accelerator pedal operation confirmation (S50) is confirmed as Tip In, and the Tip In is the APS (Acclcerator Position Scope) of the accelerator pedal when shifting from 0% to ), the acceleration request during tip-in is a phenomenon in which an impact is generated by the intersection of engine speed and turbine speed in a mechanically (or physically) engaged gear stage as the engine speed increases.

Therefore, the variable gear ratio control method is a turbine speed method that changes the CVT target pulley gear ratio to match the turbine speed to the engine, preventing the phenomenon of feeling that the vehicle is moving forward in the process of increasing the engine's idle speed to match the turbine speed. It is characterized by a variable gear ratio control method.

Meanwhile, referring to FIG. 2, the continuously variable transmission (1) includes a transmission control unit (TCU) (10) and a data detection unit (20). It includes a gear ratio map 30, a pulley device 40, a torque converter 50, and an engine 100.

For example, the TCU (10) transmits the shift lever signal of the continuously variable transmission (1) to the engine ECU (not the engine ECU), and exchanges information from the data detector 20 using CAN (Controller Area Network) as a vehicle communication network. Receive.

For example, the data detection unit 20 is composed of sensors, and the sensors include an accelerator pedal sensor 21, a vehicle speed sensor 22, a turbine sensor 23, an engine sensor 24, and a torque converter sensor 25. When applied, detection information generated from these sensors (21, 22, 23, 24, and 25) is transmitted to the TCU (10) through CAN communication. In this case, the accelerator pedal sensor 21 is APS (Accelerator Position Scope) for the pedal opening degree, the vehicle speed sensor 22 is the vehicle speed (Km/h), and the turbine sensor 23 is the turbine of the torque converter 50. Revolution Per Minute for the speed, the engine sensor 24 is the Revolution Per Minute for the engine speed, and the torque converter sensor 25 is for the operation of the torque converter clutch of the torque converter 50. It is an open/lock up signal. In this case, the torque converter open signal means clutch disengagement, and the lock up signal means clutch engagement.

For example, the gear ratio map 30 calculates the CVT target pulley gear ratio by matching the shift information detection value with the condition, and in particular, the vehicle speed information and APS information of the tip in provider 30A along with the CVT target pulley gear ratio. It is output to the TCU (10) so that the actuator of the pulley device (40) is driven. In this case, the actuator drive changes the pulley gear ratio of the pulley device 40 so that the turbine speed reduction is matched to the CVT target pulley gear ratio to which the set value (S40 in FIG. 1) is applied, and through this, tip-in according to the accelerator pedal is depressed. Prevent a crossing feeling from occurring.

For example, the pulley device 40 is composed of a drive pulley and a driven pulley tied with a belt, and the pulley gear ratio according to the shift and the set target pulley gear ratio are changed by the operation of the actuator controlled by the TCU 10.

For example, the torque converter 50 is connected to the pulley device 40 via a torque converter clutch, and is connected to the engine 100 to rotate together with the engine. In this case, the torque converter 50 is hydraulic and the engine 100 is an internal combustion engine.

Hereinafter, the turbine speed type variable gear ratio control method of the continuously variable transmission will be described in detail with reference to FIG. 2. In this case, the control subject is the TCU 10, and the control object is the turbine of the torque converter 50 by the pulley device 40.

First, the TCU 10 performs the shift information detection step of S10.

Referring to FIG. 2, the TCU 10 receives the APS signal from the accelerator pedal sensor 21, the vehicle speed (Km/h) from the vehicle speed sensor 22, the turbine sensor 23, and The rotation speed (RPM) of each engine sensor 24 is read and confirmed by the data detection unit 20, and in addition, the shift gear position (e.g., D gear) and the release of the torque converter clutch are determined by the shift lever (not shown). Disengage or engagement signals are also read and confirmed as information.

Next, the TCU 10 performs the shift entry condition confirmation step of S20, the lever position confirmation step of S21, the torque converter clutch confirmation step of S22, and the accelerator pedal APS confirmation step of S23.

Referring to FIG. 2, the TCU 10 checks the lever position, torque converter clutch, and accelerator pedal APS among the information of the data detection unit 20, and applies the following shift entry conditions to these.

Shift entry conditions:

Lever position = D (Drive)?, Torque converter clutch = Open (unfastened and open)?, Accelerator pedal APS = 0 (unoperated state)?

From this, the lever position is checked with the lever position D ready for driving (S21), the torque converter clutch is checked with the torque converter clutch open (S22), and the accelerator pedal APS is checked with the accelerator pedal APS = 0 and the accelerator pedal not pressed. (S23) etc. are performed respectively.

As a result, the TCU (10) returns to the shift information detection stage of S10 when any of the conditions of lever position D stage, torque converter clutch opening, and accelerator pedal not being operated are not met, while lever position D stage and If the conditions for torque converter clutch open are met or the conditions for lever position D, torque converter clutch open, and accelerator pedal APS = 0 are all met, the S30's CVT variable gear ratio control condition confirmation step is entered.

In this way, the CVT variable gear ratio control condition check (S30) can be entered immediately when the conditions of lever position D and torque converter clutch open are met, or when the conditions of lever position D and torque converter clutch open are met, the accelerator pedal APS = You can enter if the condition of 0 is also met. That is, the condition of the lever position D stage and the condition of the torque converter clutch open are “and”, and the condition of the accelerator pedal APS = 0 is “and” with respect to the condition of the lever position D stage and the condition of the torque converter clutch open. It can be performed in an “or” or “and” relationship.

Subsequently, the TCU 10 performs the CVT variable gear ratio control condition checking step of S30, the vehicle speed condition checking step of S31, and the speed difference checking step between the turbine and the engine at S32.

Referring to FIG. 2, the TCU 10 checks the vehicle speed, turbine speed, and engine speed among the information of the data detection unit 20, and applies the following gear ratio variable conditions to them.

Gear ratio variable conditions:

Set value A (kph) < vehicle speed < set value B (kph)?, turbine-engine speed difference > set value C (rpm)?

In this case, the vehicle speed is the detection value at the time of confirmation, “Set value A (kph)” is the lower limit value for vehicle speed and “Set value B (kph)” is the upper limit value for vehicle speed, and “Turbine-Engine speed difference” is the turbine speed difference. The speed difference between the turbine and the engine (turbine speed - engine speed) is the value obtained by subtracting the engine speed from the speed, and the “set value C (rpm)” is the allowable speed difference between the turbine and the engine, and the lower vehicle speed limit of the set value A (kph) The value is 0kph when the vehicle is stationary, the upper limit of vehicle speed for the set value B (kph) is 5kph or less when there is little vehicle movement, and the set value C (rpm) generates a crossing feel when the turbine and engine are combined. Each can be set to about 150 rpm or less. However, in the case where the lower vehicle speed limit of the set value A (kph) is when the vehicle is stopped, the upper vehicle speed limit of the set value B (kph) can be applied to the vehicle moving speed rather than the movement caused by the vehicle pressing the accelerator pedal. .

If the vehicle speed detected from this is confirmed to be between the lower limit set value A (kph) and the upper limit set value B (kph), the vehicle speed condition is checked (S31) in the driving ready state, and the turbine-engine speed difference is set to the set value C. If it is greater than (rpm), the speed difference between the turbine and the engine is checked (S32) by considering the combined impact state of the turbine and the engine.

As a result, the TCU (10) returns to the shift information detection step of S10 when the conditions of the vehicle speed and the turbine-engine speed difference are not met, while if the conditions of the vehicle speed and/or the conditions of the turbine-engine speed difference are met, the TCU (10) returns to the shift information detection step of S10. In this case, the S40 enters the pulley gear ratio reduction stage.

In this way, the pulley gear ratio reduction (S40) can be entered immediately when the vehicle speed condition is met, or when the turbine-engine speed difference condition is also satisfied while the vehicle speed condition is met. That is, the vehicle speed condition and the turbine-engine speed difference condition may be implemented in an “or” or “and” relationship.

Next, the TCU 10 changes the pulley gear ratio to decrease to the CVT target gear ratio setting in the pulley gear ratio reduction step (S40).

Referring to FIG. 2, the TCU 10 matches vehicle speed information and APS information among the information of the data detection unit 20 in the gear ratio map 30 through the tip-in providing unit 30A, and as a result, the turbine speed is reduced. Set the CVT target gear ratio for the pulley gear ratio.

In particular, the CVT target gear ratio setting satisfies the conditions of lever position D (S21) and torque converter clutch open (S22), lever position D (S21), torque converter clutch open (S22), and accelerator pedal APS = 0 (S23). Satisfying the conditions of lever position D (S21) and torque converter clutch open (S22), accelerator pedal APS = 0 (S23) and vehicle speed setting value (S31), and lever position D (S21) and torque It can be performed when the conditions of converter clutch open (S22), accelerator pedal APS = 0 (S23), vehicle speed set value (S31), and turbine-engine speed difference (S32) are met.

Subsequently, the TCU 10 performs the accelerator pedal operation confirmation step of S50, which applies the APS recheck condition. In this case, the step of checking the accelerator pedal operation (S50) is performed to clearly indicate the reduction of the cross feeling, which is the accelerator tip, which is the main feature of variable gear ratio control, and in actual control, this is a reduction in empty speed (S61). It can be processed automatically according to the pulley gear ratio change.

APS revalidation conditions:

Accelerator pedal APS > 0 (operation state)?

As a result, when the accelerator pedal APS is 0, the TCU (10) returns to the shift information detection stage of S10. On the other hand, when the accelerator pedal APS is greater than 0, the TCU (10) recognizes the accelerator pedal depressed state and controls the target pulley gear ratio of S60. Enter the stage.

Referring to FIG. 3, a tip-in situation in which the accelerator pedal is pressed while there is a turbine-engine speed difference (S32) of about 150 rpm or more (i.e., turbine speed 1250 rpm - engine speed 1100 rpm) is a torque converter 50. When combining the and engine 100, the engine speed increases higher than the turbine speed, thereby generating an engine-turbine crossing feel.

Therefore, the TCU 10 lowers the turbine speed of 1250 rpm to the engine speed of 1100 rpm by setting the CVT target gear ratio in the pulley gear ratio reduction step (S40), thereby reducing the torque converter 50 and the engine ( Even if 100) are combined, a crossing feeling does not occur.

Matching the turbine speed to the engine speed is accomplished by controlling the target pulley gear ratio of the S60.

Finally, the TCU 10 performs the target pulley gear ratio control step of S60, the turbine speed reduction start step of S61, the turbine-engine speed matching step of S62, and the turbine speed reduction stop step of S63.

Referring to FIG. 2, the TCU 10 changes the pulley ratio of the drive pulley and the driven pulley tied to the belt of the pulley device 40 to drive the actuator.

To this end, the TCU (10) drives the actuator to start reducing the turbine speed (S61), stops driving the actuator to stop reducing the turbine speed (S61), and checks the turbine-engine speed match between driving and stopping the actuator (S62). It comes true.

From this, the TCU (10) adjusts the turbine speed, which is higher than the engine speed before tip-in, to the engine speed with the pulley gear ratio reduction value (S40), and then generates a crossing feel at tip-in. It can be prevented.

As described above, the turbine speed type variable gear ratio control method of the continuously variable transmission 1 according to this embodiment includes the lever position detected in the TCU (Transmission Control Unit) 10, torque converter clutch, accelerator pedal APS, vehicle speed, and For each turbine-engine speed difference, lever position = D (Drive), torque converter clutch = Open, accelerator pedal APS = 0, lower limit set value <vehicle speed < upper limit set value, and turbine-engine speed difference > set value. The conditions are met, and the turbine speed of the torque converter 50 is adjusted to the engine speed of the engine 100 with a set value applied to the target gear ratio to reduce the pulley gear ratio when the above conditions are met, thereby adjusting the turbine speed at the time of shifting. Engine & Turbine Crossing Feel is significantly improved when tipping in at low speeds by adjusting the engine speed, and in particular, turbine speed control tailored to the engine speed is implemented by changing the CVT target pulley gear ratio. do.

1: Continuously Variable Transmission
10: TCU (Transmission Control Unit) 20: Data detection unit
21: Accelerator pedal sensor 22: Vehicle speed sensor
23: turbine sensor 24: engine sensor
25: Torque converter sensor 30: Gear ratio map
30A: Tip In providing part 40: Pulley device
50: Torque Convertor 100: Engine

Claims (13)

Apply the pulley gear ratio setting value of the continuously variable transmission by satisfying the conditions of the detected shifting information,
Controls the turbine speed of the torque converter to the above setting value to match the engine speed of the engine.
A turbine speed type variable gear ratio control method, characterized in that.
The method according to claim 1, wherein the pulley gear ratio setting value reduces the turbine speed.
The method of claim 1, wherein the shift information includes lever position and torque converter clutch,
The above conditions are met when the lever position is D (Drive) and the torque converter clutch is in an unfastened state.
The method of claim 1, wherein the shift information includes lever position, torque converter clutch, and accelerator pedal APS (Accelerator Position Scope),
The conditions are met when the lever position is D (Drive), the torque converter clutch is not engaged, and the accelerator pedal is not depressed.
The method of claim 1, wherein the shift information includes lever position, torque converter clutch, accelerator pedal APS (Accelerator Position Scope), and vehicle speed,
The conditions are met when the lever position is D (Drive), the torque converter clutch is not engaged, the accelerator pedal is not depressed, and the vehicle speed is between the lower limit and upper limit set speed. Speed variable gear ratio control method.
The method of claim 1, wherein the shift information includes lever position, torque converter clutch, accelerator pedal APS (Accelerator Position Scope), vehicle speed, and turbine-engine speed difference,
The above conditions are met when the lever position is D (Drive), the torque converter clutch is not engaged, the accelerator pedal is not depressed, the vehicle speed is between the lower limit and upper limit set speed, and the turbine-engine A turbine speed type variable gear ratio control method, characterized in that the speed difference is greater than the speed difference set value.
The method of claim 6, wherein the turbine-engine speed difference is the turbine speed minus the engine speed,
A turbine speed type variable gear ratio control method, characterized in that the speed difference setting value is 150 rpm.
Detecting a plurality of lever position, torque converter clutch, accelerator pedal APS, vehicle speed, and turbine-engine speed difference as shift information,
A shift entry condition confirmation step of determining that the lever position is in a driving position (Drive), the torque converter clutch is not engaged (Open), and the accelerator pedal APS is not detected (APS = 0);
A CVT variable gear ratio control condition confirmation step of determining that the vehicle speed is between a lower limit setting value and an upper limit setting value and that the turbine-engine speed difference is greater than the speed difference setting value,
A step of applying a setting value for reducing the pulley gear ratio of a continuously variable transmission to the target gear ratio, and
Reducing the turbine speed to the set value so that the turbine speed of the torque converter matches the engine speed of the engine.
A turbine speed type variable gear ratio control method, characterized in that performed by.
The method of claim 8, wherein the accelerator pedal APS is detected before the turbine speed decreases, thereby confirming that the accelerator pedal is depressed.
The method of claim 8, wherein the reduction control of the turbine speed is stopped when the turbine speed matches the engine speed.
A data detection unit that detects a plurality of lever position, torque converter clutch, accelerator pedal APS, vehicle speed, and turbine-engine speed difference as shift information; and
Lever position = D (Drive), torque converter clutch = Open, accelerator pedal APS = 0, lower limit setting for each of the lever position, the torque converter clutch, the accelerator pedal APS, the vehicle speed, and the turbine-engine speed difference. Each of the set values <vehicle speed, <upper limit set value, and turbine-engine speed difference> is set to meet the conditions, and when the above conditions are met, the turbine speed of the torque converter is set to the set value applied to the target gear ratio to reduce the pulley gear ratio. TCU (Transmission Control Unit) that matches the engine speed of
A continuously variable transmission characterized in that it includes.
The method of claim 11, wherein the data detection unit is linked to a sensor signal,
The sensor signal is generated from an accelerator pedal sensor that detects APS, a vehicle speed sensor that detects vehicle speed, a turbine sensor that detects turbine speed, an engine sensor that detects engine speed, and a torque converter sensor that detects the torque converter clutch operating state. A continuously variable transmission characterized in that.
The method of claim 11, wherein the TCU is associated with a gear ratio map,
The gear ratio map is a continuously variable transmission characterized in that the target gear ratio is output when the accelerator pedal is pressed based on the accelerator pedal APS information.

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