KR20130055082A - Control method for preventing backward slipping of hybrid electric vehicles on slope road - Google Patents

Abstract

PURPOSE: A control method for preventing backward slipping of a hybrid electric vehicle on a slope road is provided to prevent the vehicle from being slipped behind by applying only one gear step change control so that the vehicle is forced to change the gear step to a second step not rotating reversely in case of starting at the slope. CONSTITUTION: According to a method for preventing backward slipping of a hybrid electric vehicle on a slope road, a travelling inclination of a vehicle is judged(S102). It is checked that a brake is changed from on-state to off-state(S103). When the brake is in off-state, wheel braking by an EBS is performed by CAS or HAS(S106). A gear step control step(S108) changes the gear step of a gear transmission into a second step according to the APS on/off judgment result. When the APS is not turned on after wheel braking is done, the gear step of an automobile transmission is forced to be changed to a second step by one way clutch of the mobile transformer. [Reference numerals] (AA) Driving; (BB) Compulsory second stage(slipping prevention); (S101) Calculate load; (S102) Load >= A (according to gradient)?; (S103) Brake on & Vehicle speed = 0 ?; (S105) Operate HAS; (S106) Operate EBS(compulsory wheel lock); (S110) Required driving torque = First stage ?; (S111) First stage transmission; (S112) Second stage start

Description

Control method for preventing backward slipping of hybrid electric vehicles on slope road}

The present invention relates to a method for preventing slope incline of a hybrid vehicle, and more particularly, to a method for controlling slope incline of a hybrid vehicle using a point in which slope inclines are not generated in a two-stage sport mode of an automatic transmission for a hybrid vehicle.

Briefly looking at the system configuration of the hybrid vehicle, as shown in the configuration diagram of FIG. 7, the engine 10, the motor 20, and the six-speed automatic transmission 30 are directly connected to one axis, and the engine 10 ) And the motor 20 are connected by the engine clutch 40, and of course include an inverter, an ISG 50, a high voltage battery, and the like for their operation, and although not shown as a control means, a HCU (Hybrid Control Unit) , Motor control unit (MCU), battery management system (BMS), and the like.

The main driving mode of the hybrid vehicle based on such a configuration is, as is well known, the EV (electric vehicle) mode, which is a pure electric vehicle mode using only motor power, and the rotational force of the motor while the rotational force of the engine is the main power. HEV (hybrid electric vehicle) mode, which is used as an auxiliary mode, and regenerative braking (RB) mode, in which the braking and inertia energy of the vehicle is recovered from the motor and charged to the battery when the vehicle is driven by braking or inertia. It includes.

As a hybrid vehicle, when the mode is changed from the EV mode to the HEV mode, the engine clutch 40 is coupled, and the automatic transmission 30 is shifted to determine the driving point of the engine.

Since the automatic transmission of the hybrid vehicle as described above is directly connected to the motor, there is no torque converter, so that a large amount of slip occurs in the slope, and the slope preventing function is limited.

That is, when it is determined that the inclination of the inclination sensor is a gradient of 8% or more, the wheel pedal is braked by EBS (Electric Brake System) for 2 seconds after the CAS (Creep Aided System) is operated to turn off the brake pedal. Or the HAS (Hill Assist System) is operated at a certain load or more by determining the load due to the inclination using the acceleration sensor, and the brake pedal is turned off, Wheel braking is performed.

Thus, when starting after stopping at the ramp, the wheel braking for 2 seconds by the control of the Creep Aided System (CAS) or the wheel braking for 2 seconds by the control of the Hill Assist System (HAS), for 2 seconds The vehicle is not pushed to provide driving convenience.

However, after wheel braking is performed for two seconds under the control of CAS or HAS, if the driver does not step on the accelerator pedal and the APS (acceleration position sensor) is not turned on within two seconds, the vehicle may be pushed back. There are disadvantages.

Of course, the accelerator pedal may be pressed within 2 seconds of the wheel braking, but the driver may be pushed in a slope where the accelerator pedal is not stepped in a specific situation such as a driver's attention is low.

The present invention has been made in view of the above, the wheel braking for 2 seconds under the control of the CAS or HAS, after the driver does not step on the accelerator pedal APS (acceleration position sensor) came within 2 seconds If it is not turned on, the shift control of the inclination of the hybrid vehicle is improved by forcibly shifting the number of stages of the automatic transmission to two stages in which the output is not reversed by the one-way clutch, thereby improving driver convenience and driving safety. The purpose is to provide a method.

The present invention for achieving the above object comprises the steps of determining the inclination angle of the vehicle; Confirming that the brake is in an off state from the on state; Performing wheel braking by the EBS under control of the CAS or the HAS when the brake is off; A shift stage control step of forcibly shifting the transmission stage to two gears according to the APS on / off determination result; It provides a method for preventing slope rolling of a hybrid vehicle comprising a.

In a preferred embodiment of the present invention, the shift stage control may include: after wheel braking is performed by control of CAS or HAS in a ramp, and if the APS is not turned on, the output of the automatic transmission may not be reversed by the one-way clutch. It is characterized by consisting of a two-speed forced shift.

More preferably, the wheel braking is performed for 2 seconds after the brake off, and the shift stage control forcibly shifting to the second stage is performed 1.5 seconds after the brake off time.

In addition, after the gear shift stage is shifted to two gears, the gear shift gear may be shifted to one gear or maintained to two gears according to the required driving torque of the vehicle to start the vehicle.

Through the above-mentioned means for solving the problems, the present invention provides the following effects.

According to the present invention, after wheel braking is performed for two seconds under the control of CAS or HAS at the start of the ramp, if the APS (acceleration position sensor) is not turned on within two seconds as the driver does not press the accelerator pedal, By forcibly shifting the number of stages of the automatic transmission to two stages in which the output is not reversed by the one-way clutch, the driver's convenience and driving safety can be further improved.

In addition, only the shift stage control which eliminates the system itself in which the wheel braking of the EBS is performed by CAS or HAS control at the start of the ramp, and forcibly shifts the number of stages of the automatic transmission to two stages in which the output is not reversed by the one-way clutch. Even if it is applied, the rolling of the vehicle can be prevented.

1 is a flow chart illustrating a method for preventing slope rolling of a hybrid vehicle according to the present invention;
2 is a speed line diagram for explaining that the output of the two-stage forced shifting is not reversely rotated during the slope prevention control of the hybrid vehicle according to the present invention;
3A and 3B are waveform diagrams illustrating a method for preventing slope incline of a hybrid vehicle according to the present invention;
4 is a speed diagram at the first speed of the automatic transmission of the hybrid vehicle,
5 and 6 are a power transmission system diagram and a planetary gear lever structure diagram for an automatic transmission of a hybrid vehicle,
7 is a schematic diagram illustrating a powertrain structure of a hybrid vehicle.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the configuration and operation flow of the six-speed automatic transmission of the hybrid vehicle will be briefly described to help understanding of the present invention.

The six-speed automatic transmission is composed of three planetary gear sets, as shown in the transmission transmission system diagram of FIG. 5 and the planetary gear lever structure diagram of FIG. 6, and a third planetary gear on the input shaft IN connected to the engine side. The third sun gear S3 of the set is connected, and the third carrier C3 of the third planetary gear set and the carrier C2 of the second planetary gear set coaxially transmit power by the one-way clutch OWC. It is supposed to be done.

In addition, the second ring gear R2 of the second planetary gear set and the first carrier C1 of the first planetary gear set are connected, and the third ring gear R3 and the first planetary gear of the third planetary gear set are connected. The first ring gear R1 of the set is connected, and the output shaft OUT is connected to the first carrier C1 of the first planetary gear set.

Briefly referring to the speed diagram of FIG. 4 attached to the first-speed power flow of the automatic transmission based on this configuration, when power from the motor is input to the third sun gear S3 of the third planetary gear set, the third ring Rotation of the gear R3, transmission of power to the first ring gear R1 of the first planetary gear set connected to the third ring gear R3, and a first from the first ring gear R1. Through the process of transmitting power to the carrier (C1), the output to the output shaft (OUT) is made.

At this time, the first carrier gear S1 of the first planetary gear set, the second carrier C2 of the second planetary gear set and the third carrier C3 of the third planetary gear set are brakes LR / B, UD / B).

When the brake pedal is turned off in this first speed power flow, that is, when the driver releases the brake pedal, the output of the transmission may be switched from the forward direction to the reverse direction, and thus the vehicle may be pushed.

On the other hand, in the two-speed power flow of the automatic transmission, the forward output of the transmission cannot be reversed, and the reason thereof will be described with reference to FIG.

Power transmission flowchart of the second speed As in the first speed, when the power from the motor is input to the third sun gear S3 of the third planetary gear set, the third ring gear R3 rotates, and the third ring gear ( Through the process of transmitting power to the first ring gear (R1) of the first planetary gear set connected to R3) and the power is transmitted from the first ring gear (R1) to the first carrier (C1), the output shaft ( Output to OUT) is made.

At this time, the first sun gear (S1) of the first planetary gear set and the second sun gear (S2) of the second planetary gear set are respectively fixed by the brakes (UD / B, 26 / B), and the one-way clutch By operating the OWC, the second carrier C2 of the second planetary gear set and the third carrier C3 of the third planetary gearset are rotated coaxially, and the second speed is controlled through a gear ratio adjustment step including a process of rotating in coaxial manner. The output will be made.

When the brake pedal is turned off in this second speed power flow, that is, when the driver releases the brake pedal, the second carrier C2 of the second planetary gear set and the third carrier C3 of the third planetary gear set are used. Since only the forward rotation is possible by the operation of the one-way clutch OWC, and the reverse rotation is impossible, the output of the transmission cannot be switched from the forward direction to the reverse direction, thereby preventing the vehicle from being pushed.

The present invention focuses on the fact that the two-speed output of the automatic transmission cannot be switched from the forward direction to the reverse direction as described above, so that the vehicle can be prevented from running on a slope.

That is, according to the present invention, if the wheel braking is performed for two seconds under the control of the CAS or the HAS, and the APS (acceleration position sensor) is not turned on within two seconds as the driver does not press the accelerator pedal, as described above, The driver's convenience is achieved by controlling the shift of the second carrier C2 and the third carrier C3 by the one-way clutch so that the shift output is forcibly shifted to the second stage in which the transmission output is not reversed. It is characteristic in that it can improve driving safety more.

As an embodiment of the present invention, as shown in the accompanying FIG. 1, the step of determining the driving inclination angle of the vehicle is determined by using an acceleration sensor (LOAD) due to the inclination (S101), and the load gradient Determining if the reference value is exceeded (S102) is preceded.

Subsequently, a step (S103) of confirming that the brake is on, a step (S104) of confirming that the brake is off, a step (S105) of operating a HAS (Hill Assist System) when the brake is off, and control of the HAS After the brake pedal is turned off by (OFF), the step of performing the wheel braking by EBS for 2 seconds (S106) proceeds sequentially, and then forcibly shifts the transmission gear stage to the second gear according to the APS on / off determination result. Shift stage control is achieved.

As the shift stage control process, an APS on / off determination step S107 is first performed.

Of course, when the APS is on, since the driver has stepped on the accelerator pedal, driving of the vehicle is performed on the slope.

On the other hand, after wheel braking is performed by the control of the HAS, if the APS (acceleration position sensor) is not turned on (on) within 2 seconds, since the vehicle is pushed after 2 seconds, the shift stage control as described above is performed. It is made (S108).

That is, the wheel braking by the HAS proceeds for 2 seconds after the brake off, and the shift stage control which forcibly shifts the number of stages of the automatic transmission to the second stage where the output is not reversed by the one-way clutch is 1.5 seconds after the brake off point. Will be done.

Next, when the APS on / off determination step (S109) is repeatedly performed, and if the APS is determined to be on, the amount of driving required torque required for driving the ramp is calculated (S110), and according to the amount of driving required torque of the vehicle. The shift stage is shifted to the first stage (S111), or is maintained at the second stage as it is (S112), the vehicle is started.

On the other hand, as shown in the waveform diagram of the ramp driving test result shown in FIG. 3A, after the driver releases the brake pedal and the brake is turned off, the timing at which the motor is reversed by the anti-rolling operation by the HAS operation control is completed. It takes about 2.2sec.

That is, the anti-roll control by the HAS is operated for 2 seconds, it can be said that it takes about 0.2sec from the moment the anti-roll control of the HAS is completed to the time when the motor is reverse rotation.

In this case, since the shift time takes about 0.5 to 0.7 seconds, the shift response may be slower about 0.3 to 0.5 seconds than the HAS, but as shown in the waveform diagram of FIG. Since the results show that the second takes a long time, it can be seen that there is a vehicle speed delay time that overcomes the gradient resistance in the ramp, and as a result, the shift response time to the forced second speed does not act as a large delay factor when the ramp starts.

Therefore, by forcibly shifting the number of stages of the automatic transmission at the start of the ramp to two stages in which the output is not reversed by the one-way clutch, it is possible to further improve the driver's convenience and driving safety.

10: Engine
20: Motor
30: Automatic transmission
40: engine clutch
50: ISG

Claims (4)

Determining a driving inclination angle of the vehicle;
Confirming that the brake is in an off state from the on state;
Performing wheel braking by the EBS under control of the CAS or the HAS when the brake is off;
A shift stage control step of forcibly shifting the transmission stage to two gears according to the APS on / off determination result;
Inclined rolling prevention control method of a hybrid vehicle comprising a.
The method according to claim 1,
The shift stage control step is:
And after the wheel braking is performed, if the APS is not turned on, forcibly shifting the number of stages of the automatic transmission to two stages in which the output is not reversed by the one-way clutch.
The method according to claim 1 or 2,
The wheel braking is performed for 2 seconds after the brake off, and the shift stage control forcibly shifting to the second stage is performed 1.5 seconds after the brake off time, the control method for preventing rolling of the hybrid vehicle.
The method according to claim 1,
After the shift stage is shifted to two gears, the shift stage is shifted to one gear or maintained in two gears according to the required amount of torque required to drive the vehicle so that the vehicle starts. .

Images