Engine torque control method and system according to variable speed hydraulic

Abstract

The engine torque control method according to the transmission oil pressure performed by the engine torque control system (1) of the present application is characterized in that, at the time of automatic transmission shifting, the engine torque controller (10) calculates the required turbine torque (S20) after confirming the engine torque control condition (S10), converts the turbine torque factor learning storage value derived and stored by learning the turbine torque factor (S30) according to the shift type and the shift time into the required engine torque control value (S40), and requests (S50) as the engine torque control value, thereby taking the time when the turbine speed deviates from the current shift stage synchronous speed at the time of shifting as the start time of physical shifting, and performing new turbine torque calculation using the oil pressure at the start time as a reference, thereby preventing shift shock and transmission burnout due to inappropriate, excessively large or small engine torque in advance.

Description

Technical Field

[0001] This invention relates to engine torque control during gear shifting, and more particularly to an engine torque control system that uses the hydraulic pressure at the start of the physical gear shift as a reference in the turbine torque calculation during gear shifting to perform engine torque control in order to prevent gear shifting shocks and transmission burnout in advance. Background Technology

[0002] Typically, a vehicle's automatic transmission follows a power transmission sequence of "engine → torque converter (damping clutch) → transmission input shaft → transmission output shaft → differential gear → wheels". In this case, "→" indicates the power transmission path.

[0003] In particular, the aforementioned torque converter, as a mechanical device existing between the pump impeller and the turbine and used for the purpose of doubling torque, plays the role of transmitting power between the engine and the automatic transmission via fluid connection.

[0004] Therefore, in the power transmission sequence of the above system, the damping clutch generates heat due to slippage during the direct connection between the pump impeller and the turbine rotor, which may lead to burnout when excessive torque is introduced. To prevent this, engine torque reduction request logic is used between system controllers to address excessive torque introduction. In this case, the above system controllers can be an engine control unit (ECU) and a transmission control unit (TCU).

[0005] For example, the engine torque reduction request logic described above uses an engine torque request value in a transmission that has been calibrated by engineers through repeated testing to improve the shift feel.

[0006] However, the engine torque request value in the transmission of the above-mentioned engine torque reduction request logic is executed based on the judgment of the calibration engineer, and in particular, it is determined through trial and error to obtain a value suitable for improving the transmission feel.

[0007] In this existing method, the requested engine torque value is either too large or too small and therefore unsuitable, making it difficult to prevent transmission shocks caused by engine torque and transmission burnouts caused by transmission shocks.

[0008] In particular, the calculation of the engine torque request value in existing transmissions can only be based on the experience of calibration engineers to evaluate the shift feel. It is very difficult to find the engine torque request value according to the vehicle and transmission through repeated testing by engineers. Therefore, it has the disadvantages of being time-consuming and inefficient in finding the corresponding value. Summary of the Invention

[0009] Technical problems to be solved

[0010] In view of the problems mentioned above, the object of the present invention is to provide an engine torque control method and system based on transmission hydraulic pressure. In the calculation of turbine torque during transmission shift, the method and system use the hydraulic pressure at the start of the physical transmission shift as a reference, in particular the moment when the turbine speed deviates from the synchronization speed of the current transmission gear as the start of the physical transmission shift. By calculating the turbine torque based on the hydraulic pressure at this start moment, the method and system can prevent transmission shock and transmission burnout caused by inappropriate, excessive or insufficient engine torque in advance.

[0011] Solution

[0012] The engine torque control method based on transmission hydraulics of the present invention for achieving the objectives described above includes: a step of determining, during automatic transmission shifting, whether an engine torque control entry condition is met by an engine torque controller based on a turbine speed difference; a step of calculating a required turbine torque to prevent shift shock using at least one of turbine angular acceleration, driving resistance torque, and coupling solenoid torque; a step of calculating, under the condition that no slippage occurs during shifting, applying at least one of actual shift start time, accelerator pedal displacement, engine torque, and transmission oil temperature in the turbine torque factor learning entry condition, and applying average turbine acceleration or engine torque difference reduction in the turbine torque factor learning prohibition condition, calculating a result of learning a turbine torque factor based on the shifting time from the actual shift start time, and performing turbine torque factor learning using the value of the result as a turbine torque factor learning storage value; a step of converting the turbine torque factor learning storage value into an engine torque control value using the required turbine torque; and a step of requesting the engine torque control value from the engine.

[0013] As a preferred embodiment, the speed change status is distinguished by using a switch on / off signal for each speed change type.

[0014] In a preferred embodiment, the turbine speed difference is calculated using the formula: [turbine speed - turbine synchronization speed in the current gear], and the engine torque control entry condition is met when the turbine speed difference is above the turbine speed difference reference value.

[0015] In a preferred embodiment, the required turbine torque is calculated using the following formula: {[Turbine angular acceleration conversion value (turbine angular acceleration × inertial torque) - driving resistance torque conversion value (driving resistance torque × driving resistance coefficient) - coupling solenoid torque conversion value (coupling solenoid torque × coupling solenoid coefficient)] / turbine coefficient}.

[0016] In a preferred embodiment, the turbine angular acceleration conversion value is calculated using the following formula: [(turbine torque × turbine coefficient) + driving resistance torque conversion value + coupling solenoid torque conversion value]; the turbine angular acceleration is calculated using the following formula: [(turbine current synchronization speed - turbine target synchronization speed) / target shift time]; the driving resistance torque is calculated using the formula: (rolling resistance + slope resistance + wind resistance), the rolling resistance is calculated using the formula: [COS slope × vehicle weight × gravitational acceleration × rolling resistance coefficient], the slope resistance is calculated using the formula: [SIN slope × vehicle weight × gravitational acceleration], and the wind resistance is calculated using the formula: [vehicle speed × air density × front surface area × air resistance coefficient × 0.5].

[0017] In a preferred embodiment, the torque of the coupling solenoid is calculated using the following formula:

[0018] [((coupling solenoid hydraulic pressure × piston area) - spring force) × number of plates × 2 × plate area × 0.01 × friction factor × gravitational acceleration].

[0019] In a preferred embodiment, the condition for no fly-through is determined by the conditions for no fly-through during upshifting and no fly-through during downshifting. The condition for no fly-through during upshifting is determined by [turbo speed > current gear turbine sync speed] or [turbo speed < target gear turbine sync speed], and the condition for no fly-through during downshifting is determined by [turbo speed < current gear turbine sync speed] or [turbo speed > target gear turbine sync speed].

[0020] As a preferred embodiment, the turbine torque factor learning entry condition is satisfied when all of the following conditions are met: [the actual shift start time < the start time reference value], [sensor displacement value 1 < the accelerator pedal displacement APS < sensor displacement value 2], [engine torque value 1 < the engine torque < the engine torque value 2], and [oil temperature value 1 < the transmission oil temperature < oil temperature value 2].

[0021] As a preferred embodiment, the turbine torque factor learning prohibition condition is satisfied under one of the following conditions: [the average turbine acceleration during a predetermined time when the difference between the turbine synchronous speed and the turbine speed in the target gear is below a predetermined value > the average turbine acceleration reference value], and [the time of occurrence of the reduction in engine torque difference (engine torque - engine torque intervention) < engine torque difference reference value) > the engine torque difference reduction reference value].

[0022] In a preferred embodiment, the engine torque control value is calculated using the following formula: [Turbine torque factor learning storage value × (required turbine torque / torque converter torque multiplication ratio)], where the torque converter torque multiplication ratio is the ratio of turbine speed to engine speed.

[0023] Furthermore, the engine torque control system of the present invention for achieving the above-described objectives includes: an engine torque controller that, after confirming engine torque control conditions during automatic transmission shifting, calculates the required turbine torque, converts a turbine torque factor learning storage value into the required engine torque control value, and requests the engine torque control value, wherein the turbine torque factor learning storage value is a result value derived from learning a turbine torque factor based on the shift type and the shift time from the actual shift start time; and a vehicle data providing unit that detects sensor signals from the vehicle's engine and automatic transmission, and transmits the detected signals to the engine torque controller.

[0024] In a preferred embodiment, the engine torque controller includes: a confirmation unit that confirms the engine torque control conditions using data from the vehicle data providing unit; a calculation unit that calculates the required turbine torque when the engine torque control conditions are met; a learning unit that derives and stores the turbine torque factor learning storage value using a turbine torque factor learning mapping based on the gear shift type and shift time; a conversion unit that converts the turbine torque factor learning storage value into an engine torque control value using the required turbine torque; and a request unit that requests the engine torque control value from the engine.

[0025] Beneficial effects

[0026] The engine torque control system of this invention, based on variable-speed hydraulic engine torque control, achieves the following functions and effects.

[0027] First, by using the hydraulic pressure at the physical start of the shift in the turbine torque calculation during gear changes, optimal shift times and engine torque request values ​​can be used. Second, by requesting the required engine torque based on the shift start hydraulic pressure, shift shock is reduced, thereby improving the shift feel. Third, by requesting appropriate engine torque during shifts, excessive or insufficient engine torque is prevented in advance, thus preventing clutch disc burn-out and extending vehicle life. Fourth, the difficulty in calculating engine torque request values ​​that occurs when performing operations in a trial-and-error manner based on the judgment of calibration engineers can be resolved, and in particular, the drawbacks of long time and inefficiency in finding the corresponding value can be overcome. Attached Figure Description

[0028] Figure 1 This is a flowchart of the engine torque control method based on variable-speed hydraulics according to the present invention.

[0029] Figure 2 This is an example of the configuration of an engine torque control system according to the present invention, which utilizes the reduction of engine torque to perform engine torque control.

[0030] Explanation of reference numerals in the attached figures

[0031] 1: Engine torque control system

[0032] 10: Engine torque controller

[0033] 11: Confirmation Department

[0034] 13: Computing Department

[0035] 15: Academic Department

[0036] 17: Conversion Department

[0037] 19: Request Department

[0038] 20: Vehicle Data Provision Department Detailed Implementation

[0039] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. These embodiments are examples and can be implemented in various different forms by those skilled in the art to which the present invention pertains, and are therefore not limited to the embodiments described herein.

[0040] Reference Figure 1The characteristic of the variable hydraulic engine torque control method is that it confirms whether the engine torque control entry condition is met (S10), calculates the required turbine torque (S20), performs turbine torque factor learning (S30), then converts the engine torque control value (S40), and then requests the engine torque control value (S50).

[0041] As described above, the engine torque control method based on the transmission hydraulic system can calculate the turbine torque based on the hydraulic pressure at the moment when the turbine speed deviates from the synchronous speed of the current gear at the start of the physical shift during gear change, and then request an appropriate engine torque value to match it. This can prevent the provision of inappropriate engine torque, such as excessive or insufficient torque, that could lead to shift shock, and in particular, can prevent transmission burnout caused by shift shock.

[0042] The following is for reference Figure 2 The above-mentioned engine torque control method based on variable-speed hydraulics is explained in detail.

[0043] Reference Figure 2 The engine torque control system 1 includes an engine torque controller 10 and a vehicle data providing unit 20 employing an 8-speed automatic transmission for the front wheels. The engine torque controller 10 is functionally divided into a confirmation unit 11, a calculation unit 13, a learning unit 15 having a turbine torque factor learning map and a torque converter torque multiplication ratio map, a conversion unit 17, and a request unit 19. In this configuration, the engine torque controller 10 includes a memory housing engine torque control logic based on the transmission hydraulic system, operates using a central processing unit (CPU), and its components are interconnected via a controller area network (CAN).

[0044] Specifically, the vehicle data providing unit 20 can transmit signals from on-board sensors such as vehicle speed sensor, engine speed sensor, turbine speed sensor, hydraulic sensor, transmission switch sensor, oil temperature sensor, torque sensor, and gravity acceleration sensor to the engine torque controller 10. It can also provide the engine torque controller 10 with information about the torque converter, turbine, solenoid, piston spring, plate, etc., which are components of the automatic transmission, so that the engine torque controller 10 can calculate the turbine angular acceleration, driving resistance torque (i.e., rolling resistance, slope resistance, and wind resistance), and coupling solenoid torque.

[0045] Furthermore, the formulas used in the following description are general under the same conditions for preventing shift shock, and the control variables and variable values ​​applied to the formulas in accordance with this feature are calculated differently depending on the specifications and type of the automatic transmission, and are therefore not limited to any specific values.

[0046] The flare phenomenon refers to the instantaneous increase in engine speed (rpm) that occurs immediately after shifting to a lower gear and at the moment the current gear ratio reaches the target gear ratio, due to the rotational inertia of the transmission (varistor). This is caused by the speed of the actual drive pulley becoming faster than the speed of the target drive pulley.

[0047] First, the step (S10) above, which confirms whether the engine torque control entry conditions are met, is a step that confirms the engine torque control conditions when the vehicle is changing gears.

[0048] Therefore, the confirmation unit 11 of the engine torque controller 10 confirms the ON state of the switch for each transmission type while shifting gears by using the information provided by the vehicle data providing unit 20, and determines whether the entry condition is met by using the engine torque control entry condition confirmation formula.

[0049] Engine torque control entry condition confirmation formula: Turbine speed difference (turbine speed - current gear turbine synchronization speed) > turbine speed difference reference value — (1)

[0050] As described above, the turbine speed difference is used to confirm whether the engine torque control entry condition is met (S10).

[0051] The following section on gear shifting divides multiple gear shifting phases into gear shifting preparation intervals, actual gear shifting intervals, and gear shifting completion intervals. Each interval has a gear shifting time corresponding to the time required from start to end, and the transition state from one interval to the next interval is defined as the start time.

[0052] Next, the step (S20) of calculating the required turbine torque is a step of calculating the required turbine torque that will not cause shift shock during gear shifting, and this step is performed when the turbine speed difference between the turbine speed and the turbine synchronous speed of the current gear is greater than or equal to a predetermined difference.

[0053] Therefore, the calculation unit 13 of the engine torque controller 10 applies the information provided by the vehicle data providing unit 20 to the calculation formula of the required turbine torque.

[0054] Formula for calculating the required turbine torque: Required turbine torque = [(turbine angular acceleration × inertial torque) - (driving resistance torque × driving resistance coefficient) - (coupling solenoid torque × coupling solenoid coefficient)] / turbine coefficient — (2)

[0055] Here, 1) Turbine angular acceleration × inertial torque = (Turbine torque × Turbine coefficient) + (Drag torque × Drag coefficient) + (Coupled solenoid torque × Coupled solenoid coefficient); 2) Turbine angular acceleration = (Current turbine synchronization speed - Target turbine synchronization speed) / Target shift time (changing to a fast but shock-free shift target); 3) Drag torque = Rolling resistance (COS (gradient) × Vehicle weight × Gravitational acceleration × Rolling resistance coefficient) + Slope resistance (SIN (gradient) × Vehicle weight × Gravitational acceleration) + Wind resistance [(Vehicle speed (m / s)^2 × Air density × Front surface area × Air drag coefficient × 0.5]. Here, the above "target shift time" represents the time required from start to finish for shifting gears with the goal of preventing shift shock.

[0056] In addition, 4) the torque of the coupling solenoid = [((coupling solenoid hydraulic pressure × piston area) - spring force) × number of plates × 2 × plate area × 0.01 × friction factor × gravitational acceleration].

[0057] In addition, the inertial torque is the inertial torque value according to the specifications of the transmission, and the coefficient represents a coefficient mapping diagram that reflects the design value.

[0058] As a result, in the step (S20) of calculating the required turbine torque, the required turbine torque is calculated based on the hydraulic pressure at the moment of physical shift start during shifting, by simultaneously reflecting the characteristics of the automatic transmission and the vehicle characteristics.

[0059] Then, the above-described step of performing turbine torque factor learning (S30) is implemented by the learning unit 15 of the engine torque controller 10, which derives the learning value and stores it in the mapping map using a turbine torque factor learning mapping map based on the shift type and shift time. Here, the "shift time" refers to the time required for shifting from start to finish.

[0060] Therefore, the aforementioned step of performing turbine torque factor learning (S30) is performed by confirming whether the turbine torque factor learning entry condition is met (S31), confirming whether the turbine torque factor learning prohibition condition is not met (S32), and calculating and applying the turbine torque factor learning value based on the actual shift time (S33). Here, the aforementioned "actual shift time" refers to the actual time required for the shift from start to finish.

[0061] For example, in the step (S32) of confirming whether the turbine torque factor learning prohibition condition is not met, the turbine torque factor learning entry condition is applied under the condition that no flare occurs during gear change.

[0062] The condition for a flare to occur during an upshift is: [Turbine speed > turbine synchronization speed of the current gear] or [Turbine speed < turbine synchronization speed of the target gear] — (3)

[0063] The condition for a flare to occur during downshift is: [Turbine speed < turbine synchronization speed of the current gear] or [Turbine speed > turbine synchronization speed of the target gear] — (4)

[0064] Turbine torque factor learning entry condition: [Actual shift start time < Start time reference value] & [Sensor displacement value 1 < Accelerator pedal displacement (APS) < Sensor displacement value 2] & [Engine torque value 1 < Engine torque < Engine torque value 2] & [Oil temperature value 1 < Transmission oil temperature < Oil temperature value 2] —— (5)

[0065] Here, the actual shift start time and the reference value for the start time are defined by the transition time between the shift stages, and the application of the reference value is based on the time interval before and after the start time. Furthermore, sensor displacement value 1, engine torque value 1, and oil temperature value 1 represent the lower limit values ​​for their respective components, while sensor displacement value 2, engine torque value 2, and oil temperature value 2 represent the upper limit values ​​for their respective components.

[0066] Furthermore, the step (S32) above, which confirms whether the turbine torque factor learning prohibition condition is not met, is to avoid the situation where the learning prohibition condition of "unstable average turbine acceleration at a specific time" or "delayed engine torque control end time" is met after the turbine torque factor learning entry condition (S31) is met. For this reason, the turbine torque factor learning prohibition condition formula is used.

[0067] Turbine torque factor learning prohibition condition: [Average turbine acceleration > average turbine acceleration reference value within a predetermined time when the difference between turbine synchronous speed and turbine speed in the target gear is below a predetermined value] or [Time when the reduction of engine torque difference (engine torque - engine torque intervention) < engine torque difference reference value) occurs > engine torque difference reduction reference value] — (6)

[0068] As a result, the step (S33) above, which calculates and applies the turbine torque factor learning value based on the actual shift time, obtains the turbine torque factor learning result by using the turbine torque factor learning mapping based on the shift type and the shift time from the actual shift start time after calculating the shift time based on the shift type, and uses the result value as the turbine torque factor learning storage value (i.e., shift type, shift time).

[0069] Next, the above-mentioned step (S40) of converting the engine torque control value determines the engine torque control value required to prevent transmission shock by reflecting the calculated turbine torque factor learning value.

[0070] Therefore, the conversion unit 17 of the engine torque controller 10 applies the required engine torque control value conversion formula.

[0071] Engine torque control value conversion formula: Engine torque control value = [Turbine torque factor learning storage value (gear shift type / gear shift time) × (required turbine torque / torque converter torque multiplication ratio (ratio of turbine speed / engine speed))] — (7)

[0072] Here, the torque multiplication ratio of the aforementioned torque converter is calculated using the torque multiplication ratio mapping diagram of the torque converter.

[0073] Finally, the step of requesting the engine torque control value (S50) described above is achieved by the requesting unit 19 of the engine torque controller 10 requesting the transmitter to execute the calculated engine torque control value conversion result. In this case, the engine torque controller 10 and the engine communicate via a controller area network (CAN).

[0074] Therefore, during the shifting process of the aforementioned engine torque controller 10 in the 8-speed automatic transmission of the front wheels, it learns and calculates the turbine torque factor learning value based on the shifting time from the actual shifting start moment only during normal shifting when no overshoot occurs. In particular, it reflects the learning value of the current shifting process in the next shifting process, and then through continuous monitoring, it can reflect the turbine torque factor learning value calculated with appropriate factor learning value.

[0075] As described above, in the engine torque control method based on transmission hydraulic pressure executed by the engine torque control system 1 according to this embodiment, during the shifting process of the automatic transmission, the engine torque controller 10 calculates the required turbine torque after confirming the engine torque control entry condition (S10) (S20), converts the turbine torque factor learning storage value derived and stored by learning the turbine torque factor according to the shifting type and shifting time (S30) into the required engine torque control value (S40), and requests it as the engine torque control value (S50). Thus, the moment when the turbine speed deviates from the synchronous speed of the current shifting gear is taken as the start moment of physical shifting, and a new turbine torque calculation is performed based on the hydraulic pressure at that start moment, thereby preventing shifting shock and transmission burnout caused by inappropriate, excessive or insufficient engine torque in advance.

Claims

1. A method for controlling engine torque based on variable-speed hydraulics, comprising: When the automatic transmission shifts gears, the engine torque controller determines whether the engine torque control entry conditions are met based on the turbine speed difference. The steps for calculating the required turbine torque to prevent gear shift shock using turbine angular acceleration, driving resistance torque, and coupling solenoid torque; Under the condition that no fly-through occurs during gear shifting, the turbine torque factor learning entry condition applies at least one of the actual gear shift start time, accelerator pedal displacement, engine torque, and transmission oil temperature, and the turbine torque factor learning prohibition condition applies the average turbine acceleration or engine torque difference reduction. The result of learning the turbine torque factor based on the gear shifting time from the actual gear shift start time is calculated, and the value of the result is used as the turbine torque factor learning storage value to perform the turbine torque factor learning step. The step of converting the turbine torque factor learned and stored value into an engine torque control value using the required turbine torque; as well as The step of requesting the engine to execute the engine torque control value; The required turbine torque is calculated as follows: (Turbine angular acceleration conversion value - driving resistance torque conversion value - coupling solenoid torque conversion value) divided by turbine coefficient, where, Turbine angular acceleration conversion value equals (Turbine angular acceleration × inertial torque). The driving resistance torque conversion value is equal to (Drag torque × Drag coefficient), and The torque conversion value of the coupled solenoid is equal to (Coupled solenoid torque × Coupled solenoid coefficient); The engine torque control value is calculated as follows: Turbine torque factor learning storage value × (required turbine torque divided by torque converter torque multiplication ratio).

2. The engine torque control method based on variable-speed hydraulics according to claim 1, wherein, Regarding the state of the speed change, the speed change type is distinguished by the switch on / off signal for each speed change type.

3. The engine torque control method based on variable-speed hydraulics according to claim 1, wherein, The turbine speed difference is calculated using the formula: (Turbine speed - Current gear turbine synchronization speed). When the turbine speed difference is above the turbine speed difference reference value, the engine torque control entry condition is met.

4. The engine torque control method based on variable-speed hydraulics according to claim 1, wherein, The turbine angular acceleration conversion value is calculated as follows: (Turbine torque × turbine coefficient) + the driving resistance torque conversion value + the coupling solenoid torque conversion value.

5. The engine torque control method based on variable-speed hydraulics according to claim 1, wherein, The turbine angular acceleration is calculated as follows: (Current turbine synchronization speed - Target turbine synchronization speed) divided by the target speed change time.

6. The engine torque control method based on variable-speed hydraulics according to claim 1, wherein, The driving resistance torque is calculated using the formula: (rolling resistance + slope resistance + wind resistance). The rolling resistance is calculated as: COS (gradient) × vehicle weight × gravitational acceleration × rolling resistance coefficient. The slope resistance is calculated as: SIN (gradient) × vehicle weight × gravitational acceleration, and The wind resistance is calculated as: vehicle speed × air density × front surface area × air resistance coefficient × 0.

5.

7. The engine torque control method based on variable-speed hydraulics according to claim 1, wherein, The torque of the coupling solenoid is calculated as follows: [(coupling solenoid hydraulic pressure × piston area) - spring force] × number of plates × 2 × plate area × 0.01 × friction factor × gravitational acceleration.

8. The engine torque control method based on variable-speed hydraulics according to claim 1, wherein, The conditions for not experiencing a fly-through are determined by the conditions for not experiencing a fly-through during upshifting and the conditions for not experiencing a fly-through during downshifting. The condition that no fly-through occurs during the upshift is determined using the following: Turbine speed > turbine synchronization speed of the current gear, or Turbine speed < target gear turbine synchronization speed, and The condition that no fly-through occurs during downshifting is determined using the following: Turbine speed < turbine synchronization speed in the current gear, or Turbine speed > target gear turbine synchronization speed.

9. The engine torque control method based on variable-speed hydraulics according to claim 1, wherein, The turbine torque factor learning entry condition is satisfied if all of the following conditions are met: The actual start time of the gear shift is less than the reference value of the start time. Sensor displacement value 1 < accelerator pedal displacement < sensor displacement value 2 Engine torque value 1 < the stated engine torque < engine torque value 2, and Oil temperature value 1 < the transmission oil temperature < oil temperature value 2.

10. The engine torque control method based on variable-speed hydraulics according to claim 1, wherein, The turbine torque factor learning prohibition condition is satisfied under one of the following conditions: The average turbine acceleration is greater than the average turbine acceleration reference value within a predetermined time period during which the difference between the turbine synchronous speed and the turbine speed at the target gear is below a predetermined value; and The time when the engine torque difference decreases is greater than the time when the difference between the engine torque and the engine torque intervention is less than the engine torque difference reference value.

11. The engine torque control method based on variable-speed hydraulics according to claim 1, wherein, The torque converter's torque multiplication ratio is the turbine speed divided by the engine speed.

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