Hybrid Vehicle and Method for Controlling Its Gear Shifting

Abstract

The present invention relates to a hybrid vehicle and a method for controlling shifting thereof. A method for controlling shifting of a hybrid vehicle including an engine, an electric motor, and a stepped transmission includes: predicting a required torque reduction amount demanded by the engine and the electric motor when there is a request for shifting of the transmission; determining whether to achieve the predicted required torque reduction amount by reducing the electric motor torque or applying a reverse torque; as a result of the determination, when the predicted required torque reduction amount cannot be achieved, determining an operating point correction amount for increasing the available torque reduction amount of the electric motor; before inputting an actually required torque reduction amount, determining whether to perform a first shift control in consideration of the efficiency of the first shift control, where the first shift control is to increase the electric motor torque and reduce the engine torque according to the operating point correction amount.

Description

Technical Field

[0001] The present invention relates to a hybrid vehicle and a method for controlling shifting thereof. Background Art

[0002] In recent years, with the continuous demand for improving the fuel efficiency of vehicles and the increasingly strict regulations on vehicle emissions in many countries, the demand for environmentally friendly vehicles has increased. As a practical representative thereof, hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs) have been developed.

[0003] Hybrid vehicles travel using two power sources, namely, an engine and an electric motor. When the engine and the electric motor work in coordination, optimal output and torque can be generated. In particular, in the case of a hybrid vehicle equipped with a parallel type or a TMED type (Transmission-Mounted-Electric-Device-type) hybrid system in which an electric motor and an engine clutch (EC) are installed between the engine and the transmission, the output of the engine and the output of the electric motor can be simultaneously transmitted to the drive shaft.

[0004] Generally, in the initial acceleration stage, a hybrid vehicle travels using electric energy (i.e., EV mode). However, when using only electric energy, the amount of electric power that can be provided in response to the driver's request is limited. Therefore, at some point, it is necessary to use the engine as the main power source (i.e., HEV mode). At this time, when the difference between the revolutions per minute of the electric motor and the revolutions per minute of the engine is within a predetermined range, the hybrid vehicle operates to engage the engine clutch so that the electric motor rotates together with the engine. Summary of the Invention

[0005] The present invention relates to a hybrid vehicle and a method for controlling shifting thereof. Specific embodiments relate to a hybrid vehicle and a control method therefor, which minimize fuel loss caused by shifting intervention.

[0006] Therefore, embodiments of the present invention provide a method for more effectively performing shifting intervention control in a hybrid vehicle and a vehicle for performing the method.

[0007] Specifically, embodiments of the present invention provide a shifting control method and a vehicle for performing the method, which determine an intervention method in consideration of energy consumption when redistributing power based on a prediction of a shifting intervention amount in a hybrid vehicle.

[0008] The technical problems solved by the embodiments are not limited to the above technical problems, and according to the following description, other technical problems not described herein will become apparent to those skilled in the art.

[0009] A method for controlling gear shifting of a hybrid vehicle including an engine, an electric motor, and a stepped transmission includes: predicting a required torque reduction amount demanded by the engine and the electric motor when there is a request for gear shifting of the stepped transmission; determining whether the predicted required torque reduction amount is achieved by reducing the electric motor torque or applying a reverse torque; as a result of the determination, when the predicted required torque reduction amount cannot be achieved, determining a working point correction amount for increasing the available torque reduction amount of the electric motor; and determining whether to perform a first gear shifting control of increasing the electric motor torque and reducing the engine torque according to the working point correction amount in consideration of the efficiency of the first gear shifting control before inputting the actually required torque reduction amount.

[0010] In another embodiment of the present invention, a hybrid vehicle including an engine, an electric motor, and a stepped transmission includes: a transmission controller configured to determine whether gear shifting of the stepped transmission is required; and a hybrid controller configured to, when there is a request for gear shifting from the transmission controller, predict a required torque reduction amount demanded by the engine and the electric motor; determine whether the predicted required torque reduction amount is achieved by reducing the electric motor torque or applying a reverse torque; as a result of the determination, when the predicted required torque reduction amount cannot be achieved, determine a working point correction amount for increasing the available torque reduction amount of the electric motor; and based on the determined working point correction amount, determine whether to perform the first gear shifting control in consideration of the efficiency of the first gear shifting control; wherein the first gear shifting control is performed by increasing the electric motor torque and reducing the engine torque according to the working point correction amount before inputting the actually required torque reduction amount. Description of the Drawings

[0011] The accompanying drawings, which are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this application, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. In the drawings:

[0012] Figure 1 shows an exemplary structure of a powertrain of a general hybrid vehicle;

[0013] Figure 2 is a schematic diagram showing an example of an intervention process of upshifting in a general vehicle;

[0014] Figure 3 shows an example of a problem occurring in an intervention process in a general hybrid vehicle;

[0015] Figure 4is a schematic diagram showing an example of torque redistribution by predicting the intervention amount;

[0016] Figure 5A and Figure 5B show the changes in the engine operating points before and after shifting, respectively;

[0017] Figure 6 is a block diagram showing an example of a control system of a hybrid vehicle applicable to an embodiment of the present invention;

[0018] Figure 7 is a schematic diagram showing an example of the configuration of a hybrid controller applicable to an embodiment of the present invention;

[0019] Figure 8 is a schematic diagram showing an example of the form of environmental protection intervention according to an embodiment of the present invention;

[0020] Figure 9 is a flowchart showing an example of the process of controlling shifting according to an embodiment of the present invention; and

[0021] Figure 10 is a schematic diagram for explaining the high-efficiency operating threshold according to another embodiment of the present invention. Detailed Description of the Invention

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement them. However, the present invention can be implemented in various ways and is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description of the present invention will be omitted for clear description, and throughout the specification, similar parts are denoted by similar reference numerals.

[0023] Throughout the specification, when a part is referred to as "including" a certain component, this does not mean excluding other components, and other components can be further included unless specifically stated to the contrary. Throughout the drawings, the same reference numerals will be used to represent the same or similar components.

[0024] The structure of a hybrid vehicle will be described below with reference to Figure 1 Description of the structure of a hybrid vehicle.

[0025] Figure 1 shows an exemplary structure of the powertrain of a general hybrid vehicle.

[0026] Reference Figure 1, the powertrain of the hybrid vehicle adopts a parallel hybrid system, where the motor (or drive motor) 140 and the engine clutch 130 are installed between the internal combustion engine (ICE) 110 and the transmission 150.

[0027] Generally, when the driver presses the accelerator after starting the vehicle (i.e., the accelerator pedal position sensor is in the start mode), with the engine clutch 130 disengaged, the motor 140 is first driven using the power of the battery, and the wheels move by the power transmitted from the motor via the transmission 150 to the final drive (FD) 160 (i.e., EV mode). When greater driving force is required due to the gradual acceleration of the vehicle, the ICE 110 can be driven by operating the auxiliary motor (or starter / generator motor) 120.

[0028] Therefore, when the revolutions per minute of the ICE 110 and the revolutions per minute of the motor 140 are equal to each other, the vehicle is driven by both the ICE 110 and the motor 140 (i.e., converted from EV mode to HEV mode). When a predetermined engine shutdown condition (e.g., deceleration of the vehicle) is satisfied, the engine clutch 130 disengages and the ICE 110 stops (i.e., converted from HEV mode to EV mode). In this case, the driving force of the wheels in the vehicle is used to charge the battery 170 through the motor 140, which is called regenerative braking or braking energy regeneration. Therefore, the starter / generator motor 120 acts as a starter motor when starting the engine, and also acts as a generator when recovering the rotational energy of the engine after the vehicle starts or when the vehicle is shut down. Therefore, the starter / generator motor 120 can be called a hybrid starter generator (HSG).

[0029] Generally, the transmission 150 is a stepped transmission or a multi-plate clutch (e.g., a dual-clutch transmission (DCT)), and upshifts to the second gear according to the speed. When the transmission 150 shifts gears, especially during the upshift process, the vehicle performs control to reduce the kinetic energy (i.e., its speed) of the transmission input shaft by reducing the torque of the drive source, so as to shift gears smoothly and protect the clutch, and this aspect of control is called "intervention control". As will be described below, in a general vehicle, in order to perform intervention control, it is necessary to reduce the torque of the engine. In this case, air flow control and ignition angle control can be considered.

[0030] First, air flow control refers to a method of adjusting the amount of air and fuel being introduced currently to control the output torque. This control method advantageously improves the ignition efficiency by controlling the optimal ignition angle corresponding to the current air flow and fuel amount. However, due to the characteristics of fluid behavior, it is almost impossible to precisely control the introduced air flow and fuel amount to meet the required torque. Therefore, the torque fluctuation responsiveness is limited. Thus, this control method has high efficiency, but needs to be more robust to the errors related to the required torque tracking and response lag.

[0031] Ignition angle control refers to a method in which, for the required torque tracking, less consideration is given to efficiency. Here, considering the slow flow behavior of the fluid, in order to achieve the required torque, first, more air and fuel than the amount of air and fuel required by the engine cylinders need to be ensured (for example, torque reserve). When the excessive air and fuel are ensured, in the case where the ignition angle of the spark plug is delayed to achieve the required torque, the efficiency decreases, but the torque accuracy and responsiveness are ensured.

[0032] Therefore, generally, shift intervention control is implemented through ignition angle control for a quick response to engine torque reduction. However, as described above, when ignition angle control is executed, the amount of fuel injected is the same as in the normal control process, but the engine output decreases. Therefore, there is a problem of reduced fuel efficiency. Regardless of the control method used to reduce the engine torque, the engine torque is reduced through shift intervention control, and the wheel torque is also reduced. Therefore, there is the following problem: passengers will inevitably feel the change in torque during shifting.

[0033] However, in the case of a hybrid vehicle, in order to reduce the torque of the drive source, a negative torque is applied to the motor 140, as will be referenced Figure 2 described. In this case, the motor 140 generates electricity.

[0034] Figure 2 is a schematic diagram showing an example of the intervention process of an upshift in a general vehicle.

[0035] Figure 2 Three curves are shown. Here, the vertical axis represents intervention, the torque of the motor, and the speed of the transmission input shaft from top to bottom.

[0036] The shift process is roughly divided into a torque phase and an inertia phase. Here, the torque phase is the phase in which the speed of the input shaft increases. The inertia phase represents the phase in which the torque of the input shaft decreases and the speed of the input shaft decreases, and represents the phase in which corresponding intervention is performed when the controller for controlling the transmission issues a request for the actual intervention amount. In addition, applying a negative (-) torque to the motor represents power generation. Therefore, the electric power generated by the motor through power generation can be used to charge the battery.

[0037] However, depending on the situation, there is the following problem: only using the motor, the intervention amount cannot be satisfied, which will be described with reference to Figure 3 as follows.

[0038] Figure 3 An example of a problem that occurs during the intervention in a general hybrid vehicle is shown.

[0039] With reference to Figure 3 , the intervention amount that the motor can provide is the sum of the current torque and the reverse torque corresponding to the charging limit, and when the intervention demand (upper curve graph) exceeds the intervention amount that the motor can withstand, an additional intervention amount (i.e., ignition angle retard) needs to be satisfied by the engine. However, as described above, there is a problem that the ignition angle retard reduces the fuel efficiency.

[0040] To overcome this problem, a method is provided: predicting the intervention amount before a gear shift occurs and reallocating the torque in the powertrain according to the prediction result, which will be described with reference to Figure 4 as follows.

[0041] Figure 4 is a schematic diagram showing an example of torque reallocation by predicting the intervention amount.

[0042] With reference to Figure 4 , the intervention amount is predicted. However, when it is determined that the motor alone cannot provide the intervention amount considering the current operating state of the motor (i.e., output torque), the torque of the motor increases prematurely due to the shortage in the torque phase. In this case, the torque of the engine decreases due to the increased torque of the motor. This is because it is necessary to increase the torque of the motor to reduce the engine torque so as to maintain the total torque. In this case, the torque of the engine decreases during the torque phase, so there is no need to identify the rapidly changing ignition angle. Therefore, an air flow control method characterized by only a slightly reduced fuel efficiency can be applied.

[0043] However, when the method shown in Figure 4 is applied, the ignition angle identification control is avoided, but depending on the situation, it may be more disadvantageous in terms of fuel efficiency than the ignition angle identification control, which will be described with reference to Figure 5A and Figure 5B as follows.

[0044] Figure 5A and Figure 5B show the changes in the engine operating points before and after a gear shift, respectively.

[0045] Figure 5Ashows the case where the engine operating point is formed near the optimal operating line (OOL) before the gear shift, and Figure 5B The figure shows the case where the engine operating point is formed below OOL before the gear shift. Figure 5A and Figure 5B The common point is that the required power is maintained before and after the gear shift. In this case, it is assumed that the RPM of the operating point B after the gear shift is reduced and the torque is increased compared to the operating point A before the gear shift (e.g., upshift).

[0046] First, refer to Figure 5A ,Due to the reduction of engine torque during the gear shift, the conversion path from the working point A before the gear shift to the working point B after the gear shift remains near OOL, so the engine efficiency is not greatly reduced.

[0047] In contrast, Figure 5B In the embodiment, due to the reduction of the engine torque during the gear shift, the conversion path from the operating point A before the gear shift to the operating point B after the gear shift deviates from the OOL, so there is a problem that the engine efficiency is greatly reduced when the intervention is performed.

[0048] Therefore, when executing Figure 4 During the intervention shown, the engine efficiency decreases according to the operating point, power consumption occurs as the torque of the motor increases in the torque phase, and power consumption is also accompanied by path loss, so there is a problem that the actual energy loss is higher than Figure 3 The ignition angle identification method shown.

[0049] Before describing the method for controlling gear shifting according to an embodiment of the present invention, reference will be made to Figure 6 The relationship between the powertrain and the controller applicable to this embodiment will be described. Figure 6 The configuration can be applied to include Figure 1 A hybrid vehicle having the above-described powertrain configuration.

[0050] Figure 6 is a block diagram showing an example of a control system of a hybrid vehicle applicable to an embodiment of the present invention.

[0051] refer to Figure 6, in a hybrid vehicle suitable for an embodiment of the present invention, an internal combustion engine (ICE) 110 can be controlled by an engine controller 210, the torques of a starter / generator motor 120 and a motor 140 can be controlled by a motor control unit (MCU) 220, and an engine clutch 130 can be controlled by a clutch controller 230. Here, the engine controller 210 can also be referred to as an engine management system (EMS). A transmission 150 can be controlled by a transmission controller 250. If necessary, the starter / generator motor 120 and the motor 140 can be controlled by different separate motor controllers.

[0052] Each controller can be connected as a high-level controller in the hybrid vehicle to a hybrid controller 240 for controlling the overall operation of the powertrain, and can provide the information required for switching the driving mode and controlling the engine clutch during a gearshift process and / or the information required for controlling the engine shutdown to the hybrid controller 240, or can perform operations according to control signals under the control of the hybrid controller 240.

[0053] More specifically, the hybrid controller 240 can determine whether the mode has been switched according to the driving state of the vehicle. For example, the hybrid controller can determine the disengagement time of the engine clutch (EC) 130, and can control the hydraulic pressure when the EC disengages (in the case of a wet EC) or control the torque capacity (in the case of a dry EC). The hybrid controller 240 can determine the EC state (locked, slipping, disengaged, etc.), and can control the stop time of the fuel injection of the ICE 110. In addition, the hybrid controller can send a torque command for controlling the torque of the starter / generator motor 120 to the MCU 220 to control the engine shutdown, and can control the recovery of the engine rotational energy. The hybrid controller 240 can learn past driving data, and can calculate the distance to empty (DTE) information of the remaining fuel according to the state of charge (SoC) of the battery by applying the current driving data.

[0054] Obviously, it will be obvious to those of ordinary skill in the art that the foregoing relationship between the controllers and the function / division of the controllers is exemplary, and thus the present invention is not limited thereto. For example, the hybrid controller 240 can be implemented such that any one of the other controllers other than the hybrid controller 240 provides the corresponding function, or two or more other controllers can be allocated and provide the corresponding function.

[0055] Hereinafter, a method for controlling gearshift according to an embodiment of the present invention will be described based on the foregoing configuration of the vehicle.

[0056] Embodiments of the present invention provide a method of comparing energy consumption between a control for reducing engine torque while increasing motor torque in advance during a torque phase and an ignition angle identification control, selecting a more effective method, and predicting an intervention amount before shifting, and performing an intervention when it is determined that the motor alone cannot provide the intervention amount.

[0057] In the following description, for convenience, as Figure 4 shown, a control for reducing engine torque while increasing motor torque in advance during a torque phase and increasing the intervention amount to be provided by the motor will be referred to as "eco-friendly intervention". According to an embodiment of the present invention, it is assumed that the transmission 150 is a stepped transmission (including a DCT), whose gears are physically divided and an intervention is required during a gear shift.

[0058] Figure 7 is a schematic diagram showing an example of the configuration of a hybrid controller applicable to an embodiment of the present invention.

[0059] Referring to Figure 7 , a hybrid controller 240 according to an embodiment may include: an intervention amount predictor 241, a motor intervention determiner 243, an eco-friendly intervention determiner 245, and an intervention torque calculator 247; the intervention amount predictor 241 is configured to predict an intervention amount; the motor intervention determiner 243 is configured to determine whether the motor alone can provide the intervention amount predicted by the intervention amount predictor 241; the eco-friendly intervention determiner 245 is configured to compare energy consumption between an eco-friendly intervention control and an ignition angle retard control and determine whether to perform an eco-friendly intervention; the intervention torque calculator 247 is configured to calculate an engine torque and a motor torque for intervention according to the form of the intervention determined by the eco-friendly intervention determiner 245.

[0060] Reference will be made to the accompanying drawings and Figure 8 to describe the functions of the components of the hybrid controller 240 and the form of the intervention control. Figure 8 is a schematic diagram showing an example of the form of an eco-friendly intervention according to an embodiment of the present invention.

[0061] First, when there is a request for a gear shift from the transmission controller 250, the intervention amount predictor 241 can obtain information about the target gear, gear shift stage, gear shift category, etc. from the transmission controller 250 and can predict the intervention amount based on information about the currently required torque, vehicle speed, etc. Here, the gear shift stage can represent the process of a gear shift performed in an automatic transmission, and generally, the gear shift stage includes approximately ten stages, but the present embodiment is not limited in terms of the configuration of the gear shift stage. The gear shift category refers to a parameter indicating the characteristics of the currently executed gear shift. For example, the gear shift category can include an upshift with increasing power, a downshift with decreasing power, etc., but is not limited thereto.

[0062] The motor intervention determiner 243 can compare the intervention amount predicted by the intervention amount predictor 241 with the available motor reduction amount (i.e., the difference between the motor torque and the charge limit corresponding to Figure 3 ), and can determine whether the intervention amount can be provided only by the motor. That is, when "(predicted intervention amount) ≤ (available motor reduction amount)" is true, the motor intervention determiner 243 can determine that intervention can be performed only by the motor.

[0063] When it is determined that the entire intervention amount can be provided only by the motor, the environmental protection intervention determiner 245 can calculate the operating point correction amount (i.e., Figure 8 the change in the operating point) in the torque phase assuming that environmental protection intervention is to be performed. In this case, the operating point correction amount can be the shortage amount in the available intervention amount of the motor (i.e., operating point correction amount = predicted intervention amount - available motor reduction amount, where the available motor reduction amount is the amount obtained by subtracting the charge limit from the current motor torque).

[0064] When the operating point correction amount is calculated, the environmental protection intervention determiner 245 can determine the energy consumption during the environmental protection intervention control process. The energy consumption during the environmental protection intervention control process can be the sum of the battery energy consumed by increasing the motor torque according to the operating point correction amount and the fuel energy consumed during the control time period.

[0065] First, the battery energy consumption consumed by the motor to increase the operating point correction amount from the original torque can correspond to Figure 8 the area represented after and before the inertia phase in the middle curve graph on the left side of

[0066] The amount of fuel consumed by the engine according to the operating point correction amount can be obtained by integrating the product of the brake specific fuel consumption (BSFC) and the engine output power during the entire control time period (i.e., "∫BSFC (rpm, corrected operating point torque) * engine output power dt").

[0067] Eco-intervention determiner 245 can obtain the amount of fuel consumed when performing intervention by reducing engine torque (e.g., retarding the ignition angle) without changing the available intervention amount of the electric machine (i.e., without operating point correction). When there is no operating point correction, the amount of fuel consumed in the engine can be obtained by integrating the product of BSFC and engine output power during the entire control period (i.e., "∫BSFC (rpm, raw operating point torque) * engine output power dt").

[0068] When energy consumption is obtained using two different intervention methods, the eco-intervention determiner 245 can compare the two energy consumption amounts. Here, in the case of an eco-intervention, the battery energy consumption can be converted into fuel consumption by multiplying the battery energy consumption by the fuel / battery equivalence coefficient. The fuel / battery equivalence coefficient can be set based on the efficiency characteristics of the engine and motor. Therefore, the eco-intervention determiner 245 can compare "(battery energy consumption * fuel / battery equivalence coefficient) + the amount of fuel consumed during the operating point correction process" with the amount of fuel consumed without the operating point correction. If the amount of fuel consumed without the operating point correction is greater, it can be determined that an eco-intervention is to be performed; otherwise, it can be determined that an intervention is to be performed without the operating point correction.

[0069] When eco-intervention determiner 245 determines to execute eco-intervention, intervention torque calculator 247 distributes torque, increasing motor torque and reducing engine torque according to the operating point correction amount during the torque phase. In this case, engine torque reduction can be performed through air flow control for efficiency. In this case, engine torque can be increased and decreased at a predetermined ratio to account for responsiveness. Then, during the inertia phase, intervention torque calculator 247 provides the actual requested intervention amount received from transmission controller 250 as motor torque. If the actual requested amount exceeds the intervention amount predicted by intervention amount predictor 241, the shortfall can be compensated by retarding the engine's ignition angle.

[0070] When the gear shift is completed, the intervention torque calculator 247 may release the correction of the operating point and may restore the torque of each of the motor and the engine to its original operating point.

[0071] Obviously, when the environmental protection intervention determiner 245 determines not to perform the environmental protection intervention, the intervention torque calculator 247 may not correct the operating point in the torque phase, may allocate the torque corresponding to the available reduction of the motor in the inertia phase, and may allocate the compensation for the shortage of the intervention to the engine.

[0072] Figure 9 The flowchart obtained by summarizing the process of controlling the shift described so far is shown.

[0073] Figure 9 It is a flowchart showing an example of the process of controlling the shift according to an embodiment of the present invention.

[0074] [[ID=ll]]Reference Figure 9 , first, when there is a shift request from the transmission controller 250, the hybrid controller 240 may estimate the intervention amount based on the target gear, shift phase, shift category, accelerator pedal sensor (APS) value, vehicle speed, current gear, etc. (step S910).

[0075] The hybrid controller 240 may determine whether the intervention amount can be provided only by the motor based on the estimated intervention amount (i.e., the predicted intervention amount) (step S920), and when the predicted intervention amount is greater than the available motor reduction amount (i.e., "No" in step S920), the hybrid controller 240 may subtract the available motor reduction amount from the predicted intervention amount to determine the operating point correction amount for the environmental protection intervention (step S930).

[0076] Then, the hybrid controller 240 may compare the energy consumption with the energy consumption in the intervention process without the correction of the operating point based on the determined operating point correction amount, and may determine whether to perform the environmental protection intervention (step S940).

[0077] When the hybrid controller 240 determines to perform the environmental protection intervention because the energy consumption in the intervention process without the correction of the operating point is greater (i.e., "Yes" in step S940), the hybrid controller 240 may correct the operating points of the motor and the engine according to the correction amount in the torque phase (step S950).

[0078] Then, in the inertia phase, the hybrid controller 240 may first reduce the motor torque by the required intervention amount transmitted by the transmission controller 250, and if necessary, may also additionally reduce the engine torque by ignition angle control (step S960).

[0079] When the shift is completed, the hybrid controller 240 may restore the torques of the engine and the motor (step S970).

[0080] In the foregoing embodiments, the energy consumption in the environmentally friendly intervention with the correction of the operating point and the energy consumption without the correction of the operating point can be calculated and compared with each other. However, according to another embodiment, it can be determined whether to perform the environmentally friendly intervention (i.e., corresponding to Figure 9 operation S940) by determining whether the corrected operating point is greater than the high-efficiency operating threshold for achieving a preset minimum engine efficiency, which will be described with reference to Figure 10 .

[0081] s is a schematic diagram for illustrating the high-efficiency operating threshold according to another embodiment of the present invention.

[0082] With reference to Figure 10 , the corrected operating point can be a value obtained by subtracting the operating point correction amount from the current engine operating point, and the high-efficiency operating threshold can be set in a form obtained by subtracting a predetermined margin torque from OOL. In the Figure 10 Figure 10 shown case, the corrected operating point is equal to or less than the high-efficiency operating threshold. Therefore, the hybrid controller 240 can determine to perform the intervention without the correction of the operating point instead of performing the environmentally friendly intervention.

[0083] According to the foregoing embodiments of the present invention, it is possible to minimize the reduction in engine efficiency and path loss caused by the use of the motor during the process of avoiding engine intervention through engine ignition angle control. Therefore, the shift efficiency can also be improved under various operating conditions, thereby improving the fuel efficiency.

[0084] The hybrid vehicle according to at least one embodiment of the present invention configured as described above can effectively control the shift.

[0085] In particular, in the case where it is impossible to intervene only with the motor by predicting the intervention amount before shifting, the energy consumption when performing the control of pre-increasing the motor torque can be compared with the energy consumption when performing the ignition angle identification control, and a more effective method can be selected, thereby improving the efficiency.

[0086] Those skilled in the art will understand that the effects that can be achieved by using the present invention are not limited to the effects specifically described above, and other advantages of the present invention will be more clearly understood from the specific description.

[0087] The present invention can also be implemented as computer-readable code on a computer-readable recording medium. A computer-readable recording medium is any data storage device that can store data that can be subsequently read by a computer system. Examples of computer-readable recording media include read-only memory (ROM), random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage device.

[0088] Accordingly, the above exemplary embodiments are to be construed in all respects as illustrative and not restrictive. The scope of the present invention is to be determined by the appended claims and their legal equivalents, and not by the foregoing description, and all variations within the meaning and scope of the appended claims are intended to be embraced therein.

Claims

1. A method for controlling gear shifting of a hybrid vehicle, the hybrid vehicle including an engine, an electric motor, and a stepped transmission, the method comprising: When there is a request for gear shifting of the stepped transmission, predicting a required torque reduction amount demanded by the engine and the electric motor; Determining whether to achieve the predicted required torque reduction amount by reducing the electric motor torque or applying a reverse torque; As a result of the determination, when the predicted required torque reduction amount cannot be achieved, determining a working point correction amount for increasing the available torque reduction amount of the electric motor; Determining whether to perform a first gear shifting control or a second gear shifting control in consideration of the efficiency of the gear shifting control, where the first gear shifting control is to increase the electric motor torque and reduce the engine torque according to the working point correction amount before inputting the actually required torque reduction amount, and in the second gear shifting control, the working point correction amount is not applied to the engine torque and the electric motor torque.

2. The method according to claim 1, wherein Determining whether to perform the first gear shifting control or the second gear shifting control includes: Determining a first energy consumed during the gear shifting process by the first gear shifting control and a second energy consumed during the gear shifting process by the second gear shifting control; Determining whether to perform the first gear shifting control or the second gear shifting control according to the magnitudes of the first energy and the second energy.

3. The method according to claim 2, wherein: The first energy includes: the battery energy consumption required to increase the electric motor torque according to the working point correction amount during the gear shifting process by the first gear shifting control and the first engine fuel consumption consumed during the gear shifting process; The second energy includes: the second engine fuel consumption consumed during the gear shifting process by the second gear shifting control.

4. The method according to claim 3, wherein Determining whether to perform the first gear shifting control or the second gear shifting control includes: comparing the value obtained by adding the value converted into fuel consumption by multiplying the battery energy consumption by an equivalent coefficient to the first engine fuel consumption with the magnitude of the second engine fuel consumption.

5. The method according to claim 1, wherein Determining whether to perform the first gear shifting control or the second gear shifting control includes: Comparing the value obtained by subtracting the working point correction amount from the current engine torque with a preset threshold; When the value obtained by subtracting the working point correction amount from the current engine torque is greater than the preset threshold, determining to perform the first gear shifting control.

6. The method according to claim 5, wherein, The preset threshold is set by subtracting a predetermined margin from the optimal working line of the engine.

7. The method according to claim 1, wherein, Determining the working point correction amount includes: Subtracting the current available torque reduction amount of the electric motor from the predicted required torque reduction amount; Wherein, the current available torque reduction amount corresponds to the sum of the current torque of the electric motor and the reverse torque value corresponding to the charging limit.

8. The method according to claim 1, further comprising: When it is determined to perform the first gear shifting control, before inputting the actually required torque reduction amount, reducing the engine torque according to the working point correction amount in the gear shifting stage.

9. The method according to claim 8, wherein Reducing the engine torque is performed through air flow control to achieve a predetermined change rate.

10. The method according to claim 1, wherein, Predicting the required torque reduction amount is performed based on at least one of a target gear, a gear shifting stage, a gear shifting category, a currently required torque, or a vehicle speed.

11. A non - volatile computer - readable recording medium having recorded thereon a program for executing the method according to claim 1.

12. A hybrid vehicle, comprising: an engine; an electric motor; a stepped transmission; a transmission controller configured to determine whether a shift of the stepped transmission is required; and a hybrid controller configured to: predict a required torque reduction amount demanded of the engine and the electric motor when there is a request for a shift from the transmission controller; determine whether to achieve the predicted required torque reduction amount by reducing the electric motor torque or applying a reverse torque; when the predicted required torque reduction amount cannot be achieved, determine a working point correction amount for increasing the available torque reduction amount of the electric motor; based on the determined working point correction amount, determine whether to perform a first shift control or a second shift control in consideration of the efficiency of the shift control; wherein the first shift control is configured to be performed by increasing the electric motor torque and reducing the engine torque by the working point correction amount before inputting the actually required torque reduction amount, and in the second shift control, the working point correction amount is not applied to the engine torque and the electric motor torque.

13. The hybrid vehicle according to claim 12, wherein, The hybrid controller is configured to: determine a first energy consumed during a shift by the first shift control and a second energy consumed during a shift by the second shift control; determine whether to perform the first shift control or the second shift control based on the magnitudes of the first energy and the second energy.

14. The hybrid vehicle according to claim 13, wherein: the first energy includes: a battery energy consumption required to increase the electric motor torque by the working point correction amount during a shift by the first shift control and a first engine fuel consumption consumed during the shift; the second energy includes: a second engine fuel consumption consumed during a shift by the second shift control.

15. The hybrid vehicle according to claim 14, wherein, The hybrid controller is configured to: compare a value obtained by adding a value obtained by converting the battery energy consumption by multiplying by an equivalent coefficient into a fuel consumption to the first engine fuel consumption with the magnitude of the second engine fuel consumption; determine whether to perform the first shift control or the second shift control.

16. The hybrid vehicle according to claim 12, wherein, The hybrid controller is configured to: compare a value obtained by subtracting the working point correction amount from the current engine torque with a preset threshold; when the value obtained by subtracting the working point correction amount from the current engine torque is greater than the preset threshold, determine to perform the first shift control.

17. The hybrid vehicle according to claim 16, wherein, The preset threshold is set by subtracting a predetermined margin from an optimal operating line of the engine.

18. The hybrid vehicle according to claim 12, wherein, The hybrid controller is configured to: determine the working point correction amount by subtracting the current available torque reduction amount of the electric motor from the predicted required torque reduction amount; the current available torque reduction amount corresponds to the sum of the current torque of the electric motor and a reverse torque value corresponding to a charge limit.

19. The hybrid vehicle according to claim 12, wherein, When it is determined to perform the first shift control, the hybrid controller is configured to: perform control before inputting the actually required torque reduction amount, so as to reduce the engine torque at a predetermined rate of change according to the working point correction amount in the shift stage by air flow control.

20. The hybrid vehicle according to claim 12, wherein, The hybrid controller is configured to predict a required torque reduction amount based on at least one of a target gear position, a shift stage, a shift category, a currently required torque, or a vehicle speed.

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