KR100494887B1 - Method of decreasing engine torgue under kick-down for an automatic transmission in vehicles - Google Patents

Abstract

If the engine speed is too high during the kick-down shift, the engine torque proportional to the slip amount is reduced from that point to improve the shift response, and the shift shock is reduced to improve the performance of the transmission. To provide a method for reducing the engine torque at the time of shifting;

If it is determined that the kick-down shift is currently performed while the vehicle is being driven, the engine slip amount is calculated, and the ratio with the sync point is calculated, and the engine torque is calculated according to the calculated ratio of the excess slip amount with the sync point of the engine. The present invention provides a method for reducing engine torque during a kick-down shift of an automatic transmission for a vehicle in which a reduction amount is calculated and the control for reducing the engine torque is repeatedly returned until the kick-down shift is completed.

Description

Engine Torque Reduction Method for Kick Down of Automatic Transmission for Vehicle {METHOD OF DECREASING ENGINE TORGUE UNDER KICK-DOWN FOR AN AUTOMATIC TRANSMISSION IN VEHICLES}

The present invention relates to a method for reducing engine torque during a kick-down shift of an automatic transmission for a vehicle. More particularly, when the engine speed is excessively increased during a kick-down shift, the engine torque proportional to the slip amount is reduced from the point of time. The present invention relates to a method for reducing engine torque during a kick-down shift of an automatic transmission for a vehicle to improve responsiveness and reduce transmission shock.

 For example, an automatic transmission applied to a vehicle is controlled by a shift control device controlling a plurality of solenoid valves to control oil pressure according to a driving speed of a vehicle, an opening ratio of a throttle valve, and various detection conditions, thereby operating a gear shift of a target shift stage. To make the shift.

In other words, when the driver changes the select lever to the desired gear range, the manual valve port is changed and the hydraulic pressure supplied from the oil pump is selectively operated according to the duty control of the solenoid valve. Let this be done.

The automatic transmission operated according to this operating principle has a friction element that is deactivated in the operating state when the shift to the target shift stage is performed, and a friction element that is converted from the deactivation state to the operating state. Since the shift performance of the automatic transmission is determined according to the timing of deactivation and start of operation of these friction elements, recent studies on shift control methods for better shift performance have been actively conducted.

In view of the above, in the technical background of the present invention, in the case of a vehicle equipped with an automatic transmission, if a sudden acceleration pedal is tip-in for acceleration during driving, it is a means for increasing the driving force at least than the current driving gear stage. The kick-down shift is shifted to the shift stage of one step or less.

Accordingly, if the accelerator pedal is tip-in operation in the process of driving at the D-range 4 speed, the kick down shift is made at the 2nd speed according to the degree, and such kick-down shift is a fast kick due to the sudden stepping on the accelerator pedal. For example, downshifting, and slow kickdown, where a kickdown occurs due to lack of driving power even when the accelerator pedal is pressed down slowly.

Looking at the kick-down shift control process, as shown in (a) or (b) of FIG. 4, when the turbine speed Nt reaches a predetermined speed, a torque reduction signal for reducing a predetermined amount of engine torque for a predetermined time is generated. The pattern is generated.

In the case where the control is performed as described above, in the case of the fast kick-down shift, as shown in FIG. 4 (a), the kick-down shift is performed without occurrence of overrun of the turbine rotation speed Nt, thereby providing a different sense of shifting or shifting shock. The problem does not occur.

However, in the case of slow kick down shifting, shifting is performed in a state where the engine slip is increased (torque is increased in torque) as shown in FIG. 4 (b), in which the same setting as in the case of the fast kickdown shifting is performed. By outputting a signal of the torque reduction amount thus made, there is a problem that an overrun shock is generated.

In addition, in order to overcome the excessively increased engine torque and to achieve the kick-down shift, the hydraulic pressure of the releasing element must be set so high that the shift time becomes very long, thereby impairing the acceleration response.

Therefore, the inventors of the present invention is to focus on the torque reduction amount change controller proportional to the torque increase, if the engine speed is excessively increased during the kick-down shift, reducing the engine torque proportional to the slip amount from the point of time shift response The engine torque reduction method for the kick-down shift of the automatic transmission for a vehicle that can improve the performance and reduce the transmission shock is improved.

In order to realize this, the present invention, if it is determined that the kick-down shift is currently being made while driving the vehicle, the excess slip amount of the engine is calculated, the ratio with the sync point is calculated, and the excess slip amount and synchronization of the engine calculated thereon are calculated. The engine torque reduction method for the kick-down shift of the automatic transmission for a vehicle, characterized in that the engine torque reduction amount is calculated according to the ratio of the point and the engine control is repeatedly repeated until the kick-down shift is completed. to provide.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described in detail.

1 is a block diagram of an integrated control system for operating the present invention. When the driving state of the current vehicle is input to the ECU 20 from various sensors forming the engine control sensing unit 10, the ECU 20 may display these. The engine is controlled to the optimum state by controlling the engine control driver 30 by comparing the information with previously input data.

At the same time, the ECU 20 transmits information to the transmission control unit 40 (hereinafter referred to as TCU) if the information necessary for shift control is performed so that the shift control is performed. In this case, the information transmitted from the ECU 20 is transmitted from the ECU 20. And by comparing the information input from the shift control detecting unit 50 with the previously input data and controlling the shift control driving unit 60, the optimum shift control is achieved.

The engine control detection unit 10 is, as is known, all information necessary for engine control such as a vehicle speed sensor, a crank angle sensor, an engine speed sensor, a coolant temperature sensor, a turbine speed sensor, a throttle position sensor, and the like. The shift control detecting unit 50 refers to sensors that provide information necessary for shift control such as an input / output speed sensor, an oil temperature sensor, a pulse generator A, B, an inhibitor switch, a brake switch, and the like.

In addition, the engine control driving unit 30 means all driving units for engine control, and in the present invention, the fuel system can be specified, and the shift control driving unit 60 means all solenoid valves applied to the hydraulic control means of the automatic transmission. do.

In addition, a communication method for exchanging information between the ECU 20 and the TCU 40 may include CAN communication and serial (SIRIAL) communication, and any one of them may be selected and used.

As described above, engine control and shift control are performed based on signals input from the engine control detection unit 10 and the shift control detection unit 50. In the present invention, as shown in FIG. When the engine speed was increased above the target speed of the turbine, the engine torque reduction signal was output from that point of time until a certain time after the shift was completed.

In order to reduce the engine torque in the pattern as described above is made by the operation flow as shown in Figure 3, in this case, the signal input from the engine control detector 10 and the shift control detector 50 ECU (20) And TCU 40 perform engine control and shift control while exchanging information with each other.

At this time, if it is determined whether the kickdown shift is being made at present (S100), and if it is determined that the kickdown shift is being made, an excessive slip amount (Ns; The concept of defining the engine speed contributing to the overrun speed.) Is calculated (S110).

The excessive slip amount (Ns) in the step S110 is calculated as Ne-(No × Ro), where Ne is the engine speed (rpm), No is the transmission output speed (rpm), Ro is the target gear stage Rotation speed (rpm).

After calculating the excessive slip amount Ns in step S110, a ratio SyncS.% Is calculated (S120), and the ratio SyunR of the sync point is [(Nt-No x). Ro) / {No × (Ro-Ri)}] × 100, where Ro is the gear ratio of the current shift stage.

When the ratio (SyncR.%) With the synchronization point is calculated in step S120, the engine torque reduction amount is determined (S130), which is determined by the excess slip amount Ns obtained in steps S110 and S120 and the synchronization point. The calculated value is determined as the engine torque reduction amount according to the ratio SyncR.%, And when the engine torque reduction amount is determined in step S130, the engine torque reduction amount is outputted to reduce the engine torque. Here, the engine torque reduction amount is excessively slipped. The functional relationship obtained according to the ratio between the quantity and the synchronization point is briefly described as follows. Usually, the overrun that occurs during kick down is closely related to the engine speed at the synchronous point. That is, overrun can never occur if the engine speed is smaller than the turbine speed, which is the transmission input speed, as in the case of downshift (power off downshift) in the idle state without the engine power. However, in the power state in which the engine drives the vehicle, the engine speed is increased more than the turbine speed during the kick-down operation, so overrun occurs when the transmission hydraulic pressure is insufficient. The amount of overrun is proportional to the amount of engine speed increase during the kickdown operation. That is, the higher the engine speed at the synchronizing point, the greater the amount that the turbine departs from synchronism and rises. Therefore, regardless of the increase in the engine speed during the conventional kickdown, if the torque reduction amount is set in proportion to the degree of the engine speed being larger than the turbine speed at the synchronizing point than in the case of the torque reduction, it is proportional to the expected overrun. The effect of setting the optimum torque reduction amount in advance is obtained. The appropriate amount of torque reduction cannot be determined mathematically, and in general, it is necessary to use an empirical value obtained in the form of a map in which the engine speed can contribute to overrun, that is, a value proportional to the engine speed beyond the synchronous point. do. In other words, the ratio between the synchronization point and the synchronization point is more finely controlled by setting the turbine ascending than by outputting a constant value when determining the torque reduction execution amount. The position is converted into a ratio. That is, when the turbine before the shift is set to 100% and when the shift is completed to 0%, the position of the transient turbine speed in the middle of the shift is between 100 and 0%. In the reduction control process of the engine torque as described above, it is determined whether the current shift is now completed (S150). If the shift is not completed, the flow returns to the step S110, and the excessive slip amount (Ns) and the synchronization point after reducing the engine torque are determined. The engine torque reduction control accordingly is calculated until the shift is completed while repeatedly calculating the ratio (SyncR.%). That is, the amount of engine speed beyond the turbine synchronizing point is a proportional factor causing overrun, thereby reducing torque in proportion to this amount. In other words, if the engine rotation speed is excessively increased during the shift down, and the engine rotation speed is excessively increased during the shift, the turbine speed is controlled by reducing the torque proportional to the amount of slip of the engine from the time point. As shown in FIG. 2, the time turbine speed Nt rises only to the set target speed of the turbine speed, so that the shift is performed.

delete

delete

In comparison with the prior art, although the torque reduction element is conventionally the turbine rotational speed, the present invention is an excessive amount of engine slip, and in the related art, the torque reduction time and the torque reduction amount are fixed, but in the present invention, it varies according to the engine slip amount.

As described above, according to the present invention, if the engine speed is excessively increased during the kick-down shift, by reducing the engine torque that is proportional to the amount of slip of the engine from the time point and reducing the engine torque that is excessively raised, a good shifting feeling can be obtained. In particular, when the initial shift of the engine torque decreases, the release side hydraulic pressure can be set as low as possible, and the present invention can achieve an effect of improving shift response.

1 is a block diagram of an integrated control system for operating the present invention.

2 is a pattern diagram showing changes in engine speed and turbine speed during kickdown shift control.

3 is a flowchart of engine torque reduction according to the present invention;

4A and 4B are pattern diagrams showing changes in engine speed and turbine speed during a conventional shift control.

Claims (3)

If it is determined that the kick-down shift is currently performed while the vehicle is being driven, the engine slip amount is calculated, and the ratio with the sync point is calculated, and the engine torque is calculated according to the calculated ratio of the excess slip amount with the sync point of the engine. A method of reducing engine torque during a kick-down shift of an automatic transmission for a vehicle, characterized in that the reduction is calculated and the control for reducing the engine torque is repeatedly returned until the kick-down shift is completed. The engine of claim 1, wherein the excessive slip amount of the engine is produced by a formula of Ne-(No x Ro), wherein Ne is engine speed (rpm), No is transmission output speed (rpm), and Ro is a target. A method of reducing engine torque during a kick-down shift of an automatic transmission for a vehicle, characterized in that the gear speed is rpm. The method of claim 1, wherein the ratio with the synchronization point is calculated by the formula [(Nt-No × Ro) / {No × (Ro-Ri)}] × 100, wherein Ne is the engine speed (rpm). , No is transmission output speed (rpm), Ro is the target gear speed (rpm), Ro is the gear ratio of the current gear, the engine torque reduction method during the kick-down shift of the automatic transmission