KR101704251B1

KR101704251B1 - Transmission method during engine stop control for hev vehicle and transmission apparatus therefor

Info

Publication number: KR101704251B1
Application number: KR1020150121104A
Authority: KR
Inventors: 김성덕; 김상준
Original assignee: 현대자동차주식회사
Priority date: 2015-08-27
Filing date: 2015-08-27
Publication date: 2017-02-07

Abstract

The present invention relates to a transmission method and a transmission apparatus in controlling to stop an engine of a hybrid electric vehicle (HEV). According to the present invention, the transmission method of controlling to stop an engine of the HEV vehicle comprises: a step of requesting an engine to stop (S100); a step of changing a transmission to a lower level before the engine stops (S200); a step of separating a clutch, and stopping the engine spraying fuel (S300); and a step of controlling torque of a hybrid starter generator (HSG) motor until the engine stops, and charging a battery (S400). Thus, the present invention increases an engine revolutions per minute (RPM) through a transmission change to a lower level when the engine is controlled to stop, thereby increasing an amount of energy recovered by regenerative braking of the HSG motor.

Description

TECHNICAL FIELD [0001] The present invention relates to a shift control method and a shift control method for controlling an engine stoppage of an HEV vehicle,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a shifting method and a shifting device for controlling an engine stoppage of an HEV vehicle, and more particularly, .

Recently, HEV (Hybrid Electric Vehicle) vehicles developed for the purpose of improving environmental protection and performance have been spreading. The HEV vehicle is equipped with two drive sources, an engine and a drive motor, and is equipped with an inverter that converts the direct current of the secondary battery into an alternating current and supplies it to the motor. In addition, since the engine is stopped when the driving motor is used, it is common to provide a hybrid starting and generating (HSG) motor for starting the stopped engine. The HSG motor may be used for regenerative braking to generate a current using the rotation of the engine.

1 is a view for explaining a problem of the prior art. Referring to FIG. 1, HSG motor control is performed to maximize the regenerative braking efficiency until the RPM of the HSG motor at the time of control entry reaches 0 RPM in stopping the engine. However, the control by the conventional technique can not sufficiently regenerate braking, and the operation of the engine for charging the battery is required, so that the fuel consumption is lowered.

Patent Publication No. 2013-0030859 (March 31, 2013)

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide an engine stop control system for a vehicle, which is capable of performing engine stop control by a driver's deceleration request And to provide a shifting method and a shifting device upon engine stop control of an HEV vehicle.

The shifting method at the time of engine stop control of an HEV vehicle according to an embodiment of the present invention includes an engine stop request step (SlOO); A step S200 of shifting the speed change stage before the engine stop to the lower stage; Separating the clutch and stopping the fuel injection of the engine (S300); And controlling the torque of the HSG motor until the engine is stopped to charge the battery (S400).

The step S200 of shifting the speed change stage before the engine stop to the lower stage is a first determination step S210 of determining whether the vehicle is in the other traveling state or the deceleration traveling state.

The step S200 of shifting the speed change stage before the engine stop to the lower stage may be performed when the current speed change stage is higher than the predetermined speed change stage in the case where the vehicle is determined to be in the other traveling state or the deceleration traveling state in the first determination step And a second determination step (S220) of determining whether the current engine RPM is less than a predetermined engine RPM.

The step S200 of shifting the speed change stage before the engine stop to the lower stage is a shift stage in which the current speed change stage is higher than the predetermined speed change stage in the second determination step S220, (Step S230) of shifting down by a speed change stage derived from a current speed change stage and a current RPM by a preset reference.

And the speed change stages derived from the preset reference are one or two stages.

And the current engine RPM is increased by 1000 or 2000 RPM when the transmission is shifted down by the speed change stage derived by the preset reference.

The time required for the engine RPM to reach 0 is increased compared with the case where the downshift is not performed when the vehicle speed is lowered by the speed change stage derived from the preset reference.

The storage medium according to another embodiment of the present invention is characterized in that a shift method at the time of engine stop control of the HEV vehicle is stored.

In the engine stop control of the HEV vehicle according to another embodiment of the present invention, the transmission includes the storage medium 100; An engine (200) for generating power by burning fuel injected therein; A drive motor (300) generating power using current; A transmission 400 for converting the power generated by the engine 200 or the driving motor 300 according to the driving state of the vehicle; A clutch (500) for transmitting the power generated by the engine (200) or the drive motor (300) to the transmission (400) or for blocking transmission of the power; An HSG motor 600 for starting the stopped engine 200 or generating current by using the rotation of the engine 200; And a battery 700 that stores the current generated by the HSG motor 600 or drives the HSG motor 600 using the stored current.

In the engine stop control of the HEV vehicle, the transmission includes a sensing unit for sensing at least one of the speed of the vehicle, whether the accelerator pedal is operated, whether the brake pedal is operated, the RPM of the engine 200, (800). &Lt; / RTI >

The transmission is controlled to stop any one of the engine 200, the transmission 400, the clutch 500, and the HSG motor 600 according to information sensed by the sensing unit 800 And a control unit (900) for controlling the above-described operations.

A transmission 1000 disposed between the engine 200 and the HSG motor 600 for transmitting the power of the engine 200 or the HSG motor 600; And a control unit.

And an inverter 1100 for converting the alternating current generated in the HSG motor 600 into a direct current and storing the converted direct current in the battery 700. [

As described above, according to the present invention, the engine RPM is raised through the downshift during the engine stop control, so that the amount of energy recovered by the regenerative braking of the HSG motor can be increased. As a result, the fuel efficiency of the HEV vehicle can be improved.

1 is a view for explaining a problem of the prior art;
FIG. 2 and FIG. 3 are flowcharts of a shift method in engine stop control of an HEV vehicle according to an embodiment of the present invention. FIG.
4 is a block diagram of a speed change device in engine stop control of an EV vehicle according to another embodiment of the present invention.
5 is a view for explaining the effect of the present invention;

It is to be understood that the words or words used in the present specification and claims are not to be construed in a conventional or dictionary sense and that the inventor can properly define the concept of a term to describe its invention in the best way And should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents It should be understood that water and variations may be present. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 and FIG. 3 are flowcharts of a shift method in engine stop control of an HEV vehicle according to an embodiment of the present invention. Referring to FIGS. 2 and 3, a method of shifting an engine stop control of an HEV vehicle according to an embodiment of the present invention includes an engine stop request step S100; A step S200 of shifting the speed change stage before the engine stop to the lower stage; Separating the clutch and stopping the fuel injection of the engine (S300); And controlling the torque of the HSG motor until the engine is stopped to charge the battery (S400).

The engine stop requesting step (SlOO) is a step of inputting an engine stop signal of the HEV vehicle. In the case where the engine stop signal of the HEV vehicle is inputted, when the charging of the battery is completed by the driving force of the engine in the stopped state of the vehicle and when the heating of the exhaust gas purifying catalyst (CATALYST) There is a case. Further, there is a case where there is a deceleration request of the driver (running or decelerating) while the vehicle is running, or the driving force of the vehicle can be sufficiently covered by the driving motor alone.

The engine stop signal of the HEV vehicle may be input according to the speed of the vehicle, the operation of the accelerator pedal and the brake pedal, the amount of charge of the battery, and the exhaust gas purifying catalyst (CATALYST).

In the step S200 of shifting the speed change stage before the engine stop to the lower stage, the HSG motor adjusts the shift pattern of the transmission in the engine stop control in the case where there is the driver's deceleration request (the other running or the deceleration running) And a lower shift is performed to recover a large amount of energy. In contrast to the conventional engine stop control, in which the HSG motor is controlled to perform the maximum charge according to the RPM of the engine without any shift, the present invention actively shifts the transmission to the lower engine RPM (and the HSG The RPM of the motor) is increased, and then the HSG motor is controlled to be fully charged.

The step S200 of shifting the speed change stage before the engine stop to the lower stage is a first determination step S210 of determining whether the vehicle is in the other running state or in the deceleration running state; If it is determined in the first determination step that the vehicle is in the other-travel running state or the decelerating-travel running state, it is determined whether or not the current gear position is higher than the predetermined gear position and the current engine RPM is less than the predetermined engine RPM (S220); And when the current gear stage is higher than the predetermined gear stage in the second determining step S220 and the current engine RPM is less than the preset engine RPM, And a step S230 of shifting the speed by a speed change stage derived by the step S230.

In the first determination step (S210), the driver decides the deceleration request (the other-run or slow-down run). This is because, in order to regenerate braking of the HSG motor, it is required not only to stop the engine but also to perform the other running or decelerating running state. The first determination step S210 includes determining the speed of the vehicle sensed by the sensing unit 200, the operation of the accelerator pedal, the operation of the brake pedal, the RPM of the engine 200 and the gear stage of the transmission 400 It is judged based on whether the present running state is the other running or decelerating running.

In the second determination step S220, it is determined whether or not the downshifting is possible. That is, the downshift is performed only when the current speed change stage is higher than the predetermined speed change stage and the current engine RPM is less than the predetermined engine RPM, thereby increasing the engine RPM (and the RPM of the HSG motor connected to the engine). Otherwise, since the downshift can not be performed, the clutch is immediately disconnected and the fuel injection of the engine is stopped (S300). The predetermined speed change stage and the predetermined engine RPM may be set differently according to the type of the vehicle, the performance of the transmission, the engine, and the like.

The downshifting step S230 is a step of increasing the engine RPM (and the RPM of the HSG motor connected to the engine). The downshifting is performed by the speed change stage derived from the current speed change stage and the current RPM by a preset reference to increase the engine RPM (and the RPM of the HSG motor connected to the engine). The predetermined criteria may be set differently according to the type of the vehicle, the performance of the transmission, the engine, and the like.

The gear stage derived from the preset reference may be one or two single gears, and the current engine RPM may be increased by 1000 or 2000 RPM when shifted down by the gear stage derived by the preset reference. For example, when the speed change stage derived from the preset reference is a first stage, the first speed is shifted downward by one stage. In this case, the engine RPM (and the RPM of the HSG motor connected to the engine) rises about 1000 RPM. Further, when the speed change stage derived by the predetermined reference is two-stage, the lower speed is changed by two stages. In this case, the engine RPM (and the RPM of the HSG motor connected to the engine) rises about 2000 RPM (see FIG. 5).

In addition, when the vehicle is downshifted by the speed change stage derived from the preset reference, the time required for the engine RPM to reach zero is increased compared to the case where the downshift is not performed (refer to FIG. 5). As a result, it can be seen that the area of the cross-sectional area formed by the torque graph and the time axis (sec) of the HSG motor in the case of downshifting increases compared with the case where the downshift is not performed (conventional control). That is, it can be confirmed that the amount of the recovered energy increases.

In separating the clutch and stopping the fuel injection of the engine (S300), since the clutch is disengaged, the rotation torque of the wheel is prevented from being transmitted to the engine, and the fuel is no longer injected into the engine, It rotates only by inertia from the RPM raised in step S230. Therefore, the rotation torque of the engine due to inertia is transmitted to the HSG motor, and the power generation by the regenerative braking in the HSG motor is started. Further, the rotation torque of the wheel is transmitted to the drive motor, and the battery can be charged according to the regenerative braking separately from the HSG motor.

In step S400 of controlling the torque of the HSG motor until the engine is stopped, the torque of the HSG motor connected to the engine is controlled until the rotation torque of the engine becomes zero due to inertia to charge the battery. Accordingly, the amount of charge of the battery, that is, the energy recovered by regenerative braking of the HSG motor, can be maximized.

FIG. 4 is a block diagram of a transmission in engine stop control of an HEV vehicle according to another embodiment of the present invention. Referring to FIG. 4, the transmission in the engine stop control of the HEV vehicle according to another embodiment of the present invention includes: a storage medium 100 storing a shift method at engine stop control of the HEV vehicle; An internal combustion engine (ISG) 200 for generating power by burning the fuel injected into the internal combustion engine 200; A drive motor (300) generating power using current; A transmission 400 for converting the power generated by the engine 200 or the driving motor 300 according to the driving state of the vehicle; A clutch (500) for transmitting the power generated by the engine (200) or the drive motor (300) to the transmission (400) or for blocking transmission of the power; An HSG motor 600 for starting the stopped engine 200 or generating current by using the rotation of the engine 200; And a battery 700 that stores the current generated by the HSG motor 600 or drives the HSG motor 600 using the stored current.

When the engine stop control of the HEV vehicle is performed, the transmission senses at least one of the speed of the vehicle, the operation of the accelerator pedal, the operation of the brake pedal, the RPM of the engine 200 and the speed change stage of the transmission 400 And a sensing unit 800.

In the engine stop control of the HEV vehicle, a speed change device is disposed between the engine 200, the transmission 400, the clutch 500, and the HSG motor 600 according to information sensed by the sensing unit 800. [ And a control unit (900) for controlling any one or more of them.

The speed change device during engine stop control of the HEV vehicle includes a belt 1000 interposed between the engine 200 and the HSG motor 600 to transmit power of the engine 200 or the HSG motor 600 ); &Lt; / RTI >

In addition, the speed change device in the engine stop control of the HEV vehicle may include an inverter 1100 that converts the alternating current generated in the HSG motor 600 to a direct current and stores the converted direct current in the battery 700.

5 is a diagram for explaining the effect of the present invention. Referring to FIG. 5, in the present invention, a downshift control is performed in response to an engine stop control request. At this time, the engine RPM and the current speed change stage can be shifted down by one stage or two stages. As a result, the RPM of the engine rises and the RPM of the HSG motor connected to the engine also rises. Therefore, the amount of energy recovered by the regenerative braking of the HSG motor is increased, and the fuel economy of the HEV vehicle can be improved. Table 1 below is a table comparing the energy recovered according to the gear stage at a vehicle speed of 85 km / h. As can be seen from the following Table 1, it can be seen that the amount of energy recovered increases as the speed change stage is shifted downward.

Speed range 6 stages 4 stage 3rd stage Start of engine stop control rpm 1858 rpm 2800 rpm 4100 rpm Energy recovery due to engine stop control 2436 J 4368 J 7436 J

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory only and are not restrictive of the invention, as claimed, and will be fully understood by those of ordinary skill in the art. The present invention is not limited thereto. It will be apparent to those skilled in the art that various substitutions, modifications and variations are possible within the scope of the present invention, and it is obvious that those parts easily changeable by those skilled in the art are included in the scope of the present invention .

100 storage medium
200 engine
300 drive motor
400 transmission
500 clutch
600 HSG motor
700 battery
800 sensing unit
900 controller
1000 belt
1100 Inverter

Claims

An engine stop request step (SlOO);
A step S200 of shifting the speed change stage before the engine stop to the lower stage;
Separating the clutch and stopping the fuel injection of the engine (S300); And
And controlling the torque of the HSG motor until the engine is stopped to charge the battery (S400)
The step S200 of shifting the speed change stage before the engine stop to the lower stage,
A first determination step (S210) of determining whether the vehicle is in the other running state or in the reduced running state;
If it is determined in the first determination step that the vehicle is in the other-travel running state or the decelerating-travel running state, it is determined whether or not the current gear position is higher than the predetermined gear position and the current engine RPM is less than the predetermined engine RPM (S220); And
If it is determined in the second determination step S220 that the current gear range is higher than the predetermined gear range and the current engine RPM is less than the preset engine RPM, (S230) of shifting downward by a speed change stage derived by the shifting control means (S230).

delete

The method according to claim 1,
Wherein the gear stage derived from the preset reference is one or two stages.

The method according to claim 1,
Wherein the current engine RPM is increased by 1000 or 2000 RPM when shifting is performed by the speed change stage derived from the preset reference.

The method according to claim 1,
Wherein when the engine speed is lowered by the speed change stage derived by the predetermined reference, the time required for the engine RPM to reach 0 is increased as compared with the case where the downshift is not performed.

A storage medium storing a shift method in engine stop control of an HEV vehicle according to any one of claims 1 to 7.

A storage medium (100) according to claim 8;
An engine (200) for generating power by burning fuel injected therein;
A drive motor (300) generating power using current;
A transmission 400 for converting the power generated by the engine 200 or the driving motor 300 according to the driving state of the vehicle;
A clutch (500) for transmitting the power generated by the engine (200) or the drive motor (300) to the transmission (400) or for blocking transmission of the power;
An HSG motor 600 for starting the stopped engine 200 or generating current by using the rotation of the engine 200; And
A battery 700 that stores the current generated by the HSG motor 600 or drives the HSG motor 600 using the stored current;
And the engine is stopped.

10. The method of claim 9,
A sensing unit 800 for sensing at least one of a speed of the vehicle, an operation state of an accelerator pedal, an operation state of a brake pedal, an RPM of the engine 200, and a speed change stage of the transmission 400;
Wherein the engine is stopped when the engine is stopped.

11. The method of claim 10,
A control unit 900 for controlling at least one of the engine 200, the transmission 400, the clutch 500, and the HSG motor 600 according to information sensed by the sensing unit 800;
Wherein the engine is stopped when the engine is stopped.

12. The method of claim 11,
A belt 1000 interposed between the engine 200 and the HSG motor 600 to transmit power of the engine 200 or the HSG motor 600;
Wherein the engine is stopped when the engine is stopped.

13. The method of claim 12,
An inverter 1100 for converting an alternating current generated by the HSG motor 600 into a direct current and storing the converted direct current in the battery 700;
Wherein the engine is stopped when the engine is stopped.