Terrain Driving Mode Control Method and Device for Hybrid Vehicle

Abstract

The present invention discloses a terrain driving mode control method for a hybrid vehicle, the method comprising: defining a required torque for vehicle driving according to driver demand and driving road environment; differentiating the required torque in response to a terrain driving mode; calculating cumulative driving energy starting from an operation time point in the terrain driving mode based on the differentiated required torque; and determining a terrain driving method based on the calculated cumulative driving energy and an energy state (SoE) considering a state of charge (SoC) and voltage condition of a battery cell.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10 - 2019 - 0167878, filed on December 16, 2019, which is hereby incorporated by reference as if fully set forth herein. Technical field

[0003] The present disclosure relates to a method and apparatus for controlling a terrain drive mode of a hybrid vehicle. Background art

[0004] Generally, a hybrid electric vehicle (HEV) refers to a vehicle that uses two power sources. In most cases, the two power sources are an engine and an electric motor. Compared with a vehicle that only includes an internal combustion engine, the HEV has excellent fuel efficiency and power performance and is beneficial to reducing exhaust emissions. Therefore, the HEV has been actively developed in recent years.

[0005] In the case of such a hybrid vehicle, when the use of the electric motor increases, the state of charge (SoC) of the battery decreases. To charge the battery, the vehicle enters a battery charging mode in which the battery is charged while the vehicle is parked. Therefore, the fuel efficiency of the hybrid vehicle decreases, and the performance of the vehicle also decreases.

[0006] Generally, a vehicle has a terrain drive mode for escape. However, in the case of a hybrid vehicle, there are the following problems: when the vehicle is driven only by the engine to generate a driving force for escaping from a steep road, the fuel efficiency decreases, and when the vehicle is driven in a hybrid mode, the SoC of the battery decreases, resulting in a decrease in the driving performance of the vehicle. Summary of the invention

[0007] Accordingly, the present disclosure relates to a method and apparatus for controlling a terrain drive mode of a hybrid vehicle, which improves the fuel efficiency of the vehicle while maintaining an optimal balance of the state of charge (SoC) of the high - voltage battery when the hybrid vehicle is driven in a steep road escape mode.

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

[0009] To achieve these objects and other advantages and in accordance with the purpose of the present disclosure, as presented and broadly described herein, a method for controlling a terrain driving mode of a hybrid vehicle includes: defining a required torque for vehicle driving according to driver demand and driving road environment; differentiating the required torque in response to the terrain driving mode; calculating cumulative driving energy starting from an operating time point in the terrain driving mode based on the differentiated required torque; and determining a terrain driving method based on the calculated cumulative driving energy and an energy state (SoE) considering the state of charge (SoC) and voltage condition of the battery unit.

[0010] In some embodiments, determining the terrain driving method may include: defining at least one of a boundary point A based on SoE and a boundary point A' based on cumulative driving energy; and determining whether SoE is less than the boundary point A or the cumulative driving energy is greater than the boundary point A'.

[0011] In some embodiments, defining the boundary point based on cumulative driving energy may include: defining the boundary point based on cumulative driving energy considering at least one of road environment, driving habits, and battery charging and discharging characteristics. In some embodiments, the method may further include: defining the SoE at the time point when the vehicle is switched from EV driving to series EV driving according to the terrain driving method as the boundary point A.

[0012] In some embodiments, the method may further include: when SoE is equal to or greater than the boundary point A or the cumulative driving energy is less than the boundary point A', selecting the terrain driving method as a first control period, and controlling the vehicle to drive in the EV mode in response to the first control period.

[0013] In some embodiments, the method may further include: defining at least one of a boundary point B based on SoE and a boundary point B' based on cumulative driving energy, where SoE is the SoE available based on the current SoC and voltage according to the terrain driving method, and the boundary point B is less than the boundary point A, and the boundary point B' is greater than the boundary point A'.

[0014] In some embodiments, determining the terrain driving method may include: recalculating the cumulative driving energy from scratch; when SoE is equal to or greater than the boundary point B or the recalculated cumulative driving energy is less than the boundary point B', selecting the terrain driving method as a second control period; and controlling the vehicle to drive in the series EV mode in response to the second control period.

[0015] In some embodiments, determining the terrain driving method may include: selecting the terrain driving method for a third control period when the SoE is less than the boundary point B or the recalculated cumulative driving energy is greater than the boundary point B'; and in response to the third control period, changing the demanded torque to reduce the demanded torque and electrical load of the vehicle.

[0016] In some embodiments, determining the terrain driving method may include: determining whether the vehicle has escaped from a steep road based on the speeds of the four wheels of the vehicle and the vehicle speed.

[0017] In another aspect of the present disclosure, a terrain driving mode control device for a hybrid vehicle includes: a demanded torque determiner configured to define a demanded torque required for vehicle driving according to a driver demand and a driving road environment; a demanded torque differentiation determiner configured to differentiate the demanded torque in response to a terrain driving mode; a cumulative driving energy calculator configured to calculate a cumulative driving energy starting from a running time point in the terrain driving mode based on the differentiated demanded torque; and an electric vehicle / hybrid vehicle (EV / HEV) driving mode determiner configured to determine a terrain driving method based on the calculated cumulative driving energy and an energy state (SoE) considering a state of charge (SoC) and voltage conditions of a battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings are included to provide a further understanding of the present disclosure, are incorporated in the present application and constitute a part of the present application, the drawings illustrate embodiments of the present disclosure and are used in conjunction with the description to explain the principles of the present disclosure. In the drawings:

[0019] Figure 1 is a block diagram showing a configuration of a terrain driving mode control device according to an embodiment of the present disclosure;

[0020] Figure 2 is a diagram showing an example of a boundary point according to an energy state (SoE) according to an embodiment of the present disclosure;

[0021] Figure 3 and Figure 4 shows a driving mode according to a terrain driving mode of a hybrid vehicle according to an embodiment of the present disclosure; and

[0022] Figure 5 is a flowchart of a terrain driving mode control method according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0023] Reference will now be made in detail to exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. As used herein, the suffixes "module" and "unit" of elements are used for convenience of description and thus may be used interchangeably and have no distinguishable meaning or function.

[0024] In the description of the exemplary embodiments, it will be understood that when an element is referred to as being "on", "under", "in front of", or "behind" another element, the element may be directly on the other element or there may be intervening elements.

[0025] It will be understood that although terms such as "first", "second", "A", "B", "(a)", "(b)", etc. may be used herein to describe various elements of the present disclosure, these terms are only used to distinguish one element from another, and the basic order or sequence of the corresponding elements is not limited by these terms. It will be understood that when an element is referred to as being "connected to", "coupled to", or "accessed" another element, the one element may be "connected to", "coupled to", or "accessed" the other element via another element, or the one element may be directly connected to or directly accessed the other element.

[0026] The terms "comprising", "including", and "having" described herein should not be construed as excluding other elements, but should be construed as further including these other elements, because the corresponding elements may be included unless otherwise specifically stated. All terms, including technical or scientific terms, have the same meaning as commonly understood by those skilled in the art to which the present disclosure pertains, unless otherwise stated. Commonly used terms such as those defined in a dictionary should be construed as having a meaning consistent with the meaning of the relevant technology in the context. Unless otherwise defined in the present disclosure, these terms should not be construed in an unrealistic or overly formal manner.

[0027] Figure 1 is a block diagram showing the configuration of a terrain drive mode control device 100 according to an embodiment of the present disclosure.

[0028] Referring to Figure 1 , the terrain drive mode control device 100 may include a demand torque determiner 110, a demand torque differentiation determiner 120, an accumulated drive energy calculator 130, and an electric vehicle / hybrid electric vehicle (EV / HEV) drive mode determiner 140.

[0029] The terrain drive mode control device 100 may perform optimal charge state (SoC) balance control of the high-voltage battery according to a driving method based on a terrain drive mode, terrain detailed drive mode information, SoC information of the high-voltage battery, vehicle sensor information, etc., and may control the engine torque, HSG torque, and motor torque of the vehicle.

[0030] The required torque determiner 110 can determine the required torque for vehicle driving based on the driver's demand and the driving road environment. The required torque can be determined based on the APS opening and the vehicle speed according to Equation 1 below.

[0031] [Equation 1]

[0032] T Dmd_Driver＝f(aps,vs)

[0033] Where T Dmd_Driver can be the driving torque required for vehicle driving, aps can be the APS opening, and vs can be the vehicle speed.

[0034] Then, the required torque determiner 110 can determine the required torque by considering the correction torque according to the driving road environment (road gradient, outside temperature, etc.) in the calculated required torque according to Equation 2 below.

[0035] [Equation 2]

[0036] T Dmd_Normal = T Dmd_Driver * T factor_Env

[0037] Where T Dmd_Normal can be the required torque in the normal state of the vehicle, T Dmd_Driver can be the driving torque, and T factor_Env can be the correction torque according to the driving road environment.

[0038] The required torque differentiator 120 can apply different distribution curves according to the terrain to the distribution curve (profile) of the driving torque for escaping from a steep road according to the terrain driving mode.

[0039] In some embodiments, when the terrain of the terrain driving is snow, the required torque differentiator 120 can operate the terrain driving mode in a snow mode. In this case, the required torque differentiator 120 can reduce the required torque at vehicle start-up but determine that the required torque is similar to the normal driving torque when there is vehicle speed.

[0040] In some embodiments, when the terrain of the terrain driving is sand, the required torque differentiator 120 can operate the terrain driving mode in a sand mode. In this case, the required torque differentiator 120 can determine to control the required torque and reduce the responsiveness at vehicle start-up.

[0041] In some embodiments, when the terrain-driven terrain is muddy, the demand torque differentiator 120 may operate the terrain drive mode in a mud / ruts mode. In this case, the demand torque differentiator 120 may determine an increase in the demand torque and responsiveness when controlling the vehicle to start.

[0042] Therefore, the demand torque differentiator 120 may calculate the demand torque according to the terrain drive mode according to Equation 3 below, and may generate a torque command considering the terrain.

[0043] [Equation 3]

[0044] T Dmd = T Dmd_Normal * T factor_terrain

[0045] where T Dmd may be the demand torque according to the terrain drive mode, T Dmd_Normal may be the demand torque in the normal state of the vehicle, and T factor_terrain may be the correction torque according to the terrain drive mode.

[0046] The cumulative drive energy calculator 130 may accumulate the demand torque according to the terrain drive mode from the time point of entering the terrain drive mode according to Equation 4 below to calculate the cumulative drive energy.

[0047] [Equation 4]

[0048]

[0049] where E terrain may be the cumulative drive energy, and T Dmd may be the demand torque according to the terrain drive mode.

[0050] The EV / HEV drive mode determiner 140 may determine the terrain drive method based on the state of charge (SoE) considering the SoC and voltage conditions of the battery cells and the cumulative drive energy received from the cumulative drive energy calculator 130.

[0051] To this end, the EV / HEV drive mode determiner 140 may define a boundary based on the cumulative drive energy considering the state of the vehicle system for the drive energy consumed during a specific time period in the terrain drive mode. The boundary will be described in detail with reference to Figure 2 The boundary will be described in detail.

[0052] The EV / HEV drive mode determiner 140 may select one of the first control period, the second control period, the third control period, and the fourth control period of the drive method according to the terrain drive mode based on the cumulative drive energy and the SoE.

[0053] When the energy state (SoE) considering the SoC and voltage conditions of the battery cell is equal to or greater than the boundary point A and the cumulative driving energy accumulated from the running time point in the terrain-driven mode is less than the boundary point A', the EV / HEV drive mode determiner 140 may execute the first control cycle to drive the vehicle in the EV mode.

[0054] The EV / HEV drive mode determiner 140 may recalculate the cumulative driving energy from the beginning, and when the SoE is equal to or greater than the boundary point B or the recalculated cumulative driving energy is less than the boundary point B', the EV / HEV drive mode determiner 140 may execute the second control cycle to drive the vehicle in the series EV mode.

[0055] In some embodiments, when the vehicle is restricted on a steep road and cannot be driven, engine stall occurs due to the speed difference between the engine and the motor when the engine clutch is engaged in the TMED system, so the engine clutch cannot be engaged. That is, when the driving force of the engine cannot be transmitted through the transmission, the motor directly connected to the engine can be used to charge and the charged energy can be used to execute the control of transmitting the driving force using the drive motor directly connected to the transmission.

[0056] For this reason, vehicle engine control can be performed through partial load control to optimize fuel efficiency. In some embodiments, partial load control can be performed to conform to an air-fuel ratio of 14.6:1.

[0057] When the charging torque and SoC according to the SoC of the high-voltage battery and the driver's demanded torque are low, in order to prevent over-discharge, the vehicle HSG can be controlled to increase the charging amount of the HSG to prevent the SoC of the high-voltage battery from decreasing.

[0058] Therefore, the EV / HEV drive mode determiner 140 can perform vehicle motor control to meet the demanded torque, which is the sum of the engine friction torque and the charged HSG torque.

[0059] Therefore, the EV / HEV drive mode determiner 140 can execute the SoC defense strategy by controlling the HEV drive mode to change in the second control cycle. That is, the defense strategy in the second control cycle can increase the engine torque, the excess torque of the engine can be converted into generator energy using the HSG connected to the engine, the converted energy can be used to charge the high-voltage battery, and the charged energy can be used as the driving force of the motor, thereby minimizing the SoC discharge.

[0060] The EV / HEV drive mode determiner 140 may recalculate the cumulative driving energy from scratch, and when the SoE is less than the boundary point B or the recalculated cumulative driving energy is greater than the boundary point B', the EV / HEV drive mode determiner 140 may execute a third control cycle for reducing the demand torque. That is, when the cumulative driving energy is greater than the boundary point B', the EV / HEV drive mode determiner 140 may execute a third control cycle in which the demand is higher than the driver's demand for system protection to maintain vehicle driving considering the vehicle system.

[0061] When the SoC of the hybrid vehicle is too low to adversely affect the driving performance and it is difficult to bear the entire electric load, the EV / HEV drive mode determiner 140 may execute a third control cycle for reducing the demand torque based on the SoE usage to restore the SoC without entering such a situation. That is, the EV / HEV drive mode determiner 140 may control the vehicle to drive in the HEV mode through the third control cycle, thereby enabling SoC defense.

[0062] Therefore, the EV / HEV drive mode determiner 140 may execute the SoC defense strategy by controlling the third control cycle to change the HEV drive mode. That is, the defense strategy in the third control cycle may reduce the driver's demand torque to protect the vehicle system.

[0063] When the speed difference Diff of the four wheels of the vehicle slip is equal to or less than a specific value and the vehicle speed is equal to or greater than a specific value, the EV / HEV drive mode determiner 140 may determine that the vehicle has escaped from a steep road and may execute a fourth control cycle to drive the vehicle in normal HEV.

[0064] Therefore, when checking whether the vehicle has escaped from a steep road, the EV / HEV drive mode determiner 140 may convert the drive torque control to normal control and may execute a fourth control cycle.

[0065] Figure 2 is a diagram showing an example of boundary points according to SoE according to an embodiment of the present disclosure.

[0066] In Figure 2 the shown graph, the horizontal axis is the SoC of the battery and the vertical axis is the open circuit voltage (OCV) of the battery.

[0067] Figure 2 shows boundary points A and B in the energy state (SoE) considering the SoC and voltage conditions of battery cells for SoC balance of the vehicle.

[0068] In this case, the SoE may be the available battery energy and may be defined according to Equation 5 below.

[0069] [Formula 5]

[0070]

[0071] E rem = Q rem U ocv|soc = [0%, SOC], E max = Q max U ocv|soc = [0%, 100%]

[0072] The boundary point A can correspond to the "Normal SoC" region required during hybrid drive and can be the set reference of the SoC required for engine drive to prevent the SoC of the vehicle from discharging.

[0073] In this case, the boundary point A can be set as the SoE at the time point when the vehicle converts from EV drive to series EV drive. That is, the boundary point A can be defined according to {Available battery energy amount = (Current SoE - SoE required for conversion from EV to series EV) * High-voltage battery capacity (Kwh)}.

[0074] The boundary point B can correspond to the "Critical Low" region, and the SoC reference can be the set reference of the SoC required to prevent adverse effects on the SoC of vehicle systems such as air conditioners or auxiliary batteries that use the high-voltage battery, prevent a reduction in drive performance, and protect the system when the energy of the high-voltage battery in a hybrid electric vehicle (HEV) and a plug-in hybrid electric vehicle (PHEV) is insufficient.

[0075] In this case, the boundary point B can be defined by calculating the SoE available based on the current SoC and voltage. That is, the boundary point B can be defined according to {Available battery energy amount = (Current SoE - SoE required for conversion from EV to series EV) * High-voltage battery capacity (Kwh)}.

[0076] Figure 3 and Figure 4 shows a drive mode according to the terrain drive mode of a hybrid vehicle according to an embodiment of the present disclosure.

[0077] In Figure 3 and Figure 4 In the shown curve graphs, the horizontal axis is time and the vertical axis is cumulative drive energy.

[0078] Referring to Figure 3 and Figure 4 Boundary points A' and B' can be defined considering the state of the vehicle system for the drive energy consumed at a specific time in the terrain drive mode.

[0079] In this case, as Figure 2 shown, boundary point A and boundary point B can be set based on the SoE of the battery, the set boundary point A and boundary point B can be converted into an accumulated driving energy value, and boundary point A' and boundary point B' based on the accumulated driving energy can be set.

[0080] When the boundary point A and boundary point B based on the SoE are converted into the boundary point A' and boundary point B' based on the accumulated driving energy, at least one of the road environment, driving habits, and battery charge and discharge characteristics can be considered to change the calculated value.

[0081] As Figure 3 shown, when the accumulated driving energy accumulated from the running time point in the terrain driving mode is less than boundary point A', the vehicle can be controlled in the first control cycle of the driving method. Therefore, when the SoE at the time point of entering the terrain driving mode is higher than the boundary point A based on the SoE, the vehicle can calculate the available energy based on the remaining SoE, and can perform the EV driving mode based on the calculated available energy. In this case, the EV driving mode can be a driving mode that satisfies the driver's required torque through an electric motor.

[0082] The vehicle can recalculate the accumulated driving energy from the beginning, and when the SoE is equal to or greater than boundary point B or the recalculated accumulated driving energy is less than boundary point B', the vehicle can be controlled in the second control cycle of the driving method.

[0083] Therefore, when the SoE at the time point of entering the terrain driving mode is lower than the boundary point A based on the SoE, the vehicle can immediately enter the second control cycle and can perform the series EV driving mode. In this case, the series EV driving mode can be a driving mode having the same driving strategy as the EV mode, but can also be a driving mode in which the engine is driven to use the HSG to charge using the excess energy of the engine and increase the EV available energy.

[0084] As Figure 4 shown, the accumulated driving energy can be recalculated from the beginning, and when the SoE is less than boundary point B or the recalculated accumulated driving energy is greater than boundary point B', the control can be performed in the third control cycle of the driving method.

[0085] Therefore, the vehicle can change the driver's required torque in response to the third control cycle. Therefore, the driver's required torque can be reduced, and the reduced torque amount f of the required torque can be defined according to the function of the remaining SoC and the power consumption power of the high-voltage battery. de-rating。The remaining SoC can be the margin between the current SoC and the SoC that causes the system to shut down, and the power load can be the power consumption available through the high-voltage battery. Therefore, when the power load is high, the SoE can be consumed more quickly.

[0086] Therefore, the cumulative energy amount in the third control period can be calculated according to Equation 6 below.

[0087] [Equation 6]

[0088]

[0089] where E terrain can be the cumulative driving energy, and T Dmd can be the required torque according to the terrain driving mode.

[0090] Figure 5 is a flowchart of a terrain driving mode control method according to an embodiment of the present disclosure.

[0091] Referring to Figure 5 , when the vehicle enters the terrain driving mode (S501), the terrain driving mode control device 100 can define the required torque (S502).

[0092] In some embodiments, the required torque T in the case of normal driving Dmd_Normal can be {driving torque T Dmd_Driver * correction torque T according to the driving road environment factor_Env}.

[0093] In some embodiments, the required torque T in the case of entering the terrain driving mode Dmd can be {driving torque T for escaping from a steep road factor_terrain * required torque T in the case of normal driving Dmd_Normal}.

[0094] In some embodiments, the required torque T when entering the third control period Dmd can be {reduction torque amount f of the required torque de-rating * driving torque T for escaping from a steep road factor_terrain * required torque T in the case of normal driving Dmd_Normal}.

[0095] After operation S502, the terrain driving mode control device 100 can detect whether the vehicle has escaped from the steep road (S503). In this case, when the speed difference Diff of the four wheels of the vehicle slipWhen it is equal to or less than a specific value and the vehicle speed is equal to or greater than a specific value, the terrain driving mode control device 100 can determine that the vehicle has escaped from a steep road.

[0096] After operation S503, the terrain driving mode control device 100 can define boundary point A based on SoE considering the SoC and voltage conditions of the battery cells, and can define boundary point A' of the cumulative driving energy from the time point of entering the terrain driving mode based on boundary point A (S504).

[0097] After operation S504, the terrain driving mode control device 100 can determine whether the SoE is less than boundary point A or whether the cumulative driving energy is greater than boundary point A' (S505).

[0098] After operation S505, when the cumulative driving energy is less than boundary point A' and the energy state (SoE) considering the SoC and voltage conditions of the battery cells is equal to or greater than boundary point A ( "No" in S505), the terrain driving mode control device 100 can detect whether the vehicle has escaped from a steep road (S506).

[0099] After operation S506, as a detection result, when the vehicle fails to escape from a steep road ( "No" in S506), the terrain driving mode control device 100 can select the first control cycle of the driving method of the terrain driving mode and can control the vehicle to drive in the EV mode (S507).

[0100] After operation S506, as a detection result, when the vehicle has escaped from a steep road ( "Yes" in S506), the terrain driving mode control device 100 can select the fourth control cycle of the driving method of the terrain driving mode and can control the vehicle to drive in the normal HEV mode (S531).

[0101] After operation S505, when the SoE is less than boundary point A or the cumulative driving energy is greater than boundary point A' ( "Yes" in S505), the terrain driving mode control device 100 can define boundary point B based on SoE considering the SoC and voltage conditions of the battery cells, and can define boundary point B' of the cumulative driving energy based on boundary point B (S511).

[0102] After operation S511, the terrain driving mode control device 100 can determine whether the SoE is less than boundary point B or whether the recalculated cumulative driving energy is greater than boundary point B' (S512).

[0103] After operation S512, when the SoE is equal to or greater than the boundary point B or the recalculated cumulative driving energy is less than the boundary point B' ( "No" in S512), the terrain driving mode control device 100 may detect whether the vehicle has escaped from the steep road (S513).

[0104] After operation S513, as a detection result, when the vehicle fails to escape from the steep road ( "No" in S513), the terrain driving mode control device 100 may select the second control period of the driving method of the terrain driving mode, and may control the vehicle to be driven in the series EV mode (S514).

[0105] After operation S513, as a detection result, when the vehicle escapes from the steep road ( "Yes" in S513), the terrain driving mode control device 100 may select the fourth control period of the driving method of the terrain driving mode, and control the vehicle to be driven in the normal HEV mode (S531).

[0106] After operation S512, when the SoE is less than the boundary point B or the recalculated cumulative driving energy is greater than the boundary point B' ( "Yes" in S512), the terrain driving mode control device 100 may change the driver demand torque (S521). In this case, the changed driver demand torque may be the torque corresponding to the third control period.

[0107] After operation S521, the terrain driving mode control device 100 may detect whether the vehicle has escaped from the steep road (S522).

[0108] After operation S522, as a detection result, when the vehicle fails to escape from the steep road ( "No" in S522), the terrain driving mode control device 100 may select the third control period of the driving method of the terrain driving mode, and may perform control to reduce the demand torque and power load of the vehicle (S523).

[0109] After operation S522, as a detection result, when the vehicle escapes from the steep road ( "Yes" in S522), the terrain driving mode control device 100 may select the fourth control period of the driving method of the terrain driving mode, and may control the vehicle to be driven in the normal HEV mode (S531).

[0110] The terrain driving mode control method and device of the hybrid vehicle according to the present disclosure can minimize the entry into the battery charging mode by controlling the terrain driving mode of the battery, thereby improving fuel efficiency and maintaining performance.

[0111] Those skilled in the art will understand that the effects that can be achieved using the present disclosure are not limited to the specific content described above, and other advantages of the present disclosure will be more clearly understood from the detailed description.

[0112] The above-described method according to an embodiment can also be implemented as computer-readable code in a computer-readable recording medium. Examples of the computer-readable recording medium include read-only memory (ROM), random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage device, etc. The computer-readable recording medium can also be distributed over a networked computer system so as to store and execute the computer-readable code in a distributed manner. In addition, programmers in the field to which the present disclosure pertains can easily understand the functional programs, codes, and code segments for implementing the present disclosure.

Claims

1. A terrain driving mode control method for a hybrid vehicle, comprising: Defining a required torque for vehicle driving according to driver demand and driving road environment; Differentiating the required torque in response to the terrain driving mode; Calculating the cumulative driving energy starting from the operation time point in the terrain driving mode based on the differentiated required torque; And Determining a terrain driving method based on the calculated cumulative driving energy and the energy state i.e., SoE considering the state of charge i.e., SoC and voltage condition of the battery cell.

2. The method according to claim 1, wherein Determining the terrain driving method includes: Defining at least one of a boundary point A based on the SoE and a boundary point A' based on the cumulative driving energy; and Judging whether the SoE is less than the boundary point A or whether the cumulative driving energy is greater than the boundary point A'.

3. The method according to claim 2, wherein Defining the boundary point based on the cumulative driving energy includes: Defining the boundary point based on the cumulative driving energy in consideration of at least one of road environment, driving habit, and battery charging and discharging characteristics.

4. The method according to claim 2, further comprising: Defining the SoE at the time point when the vehicle is converted from EV driving to series EV driving according to the terrain driving method as the boundary point A.

5. The method according to claim 4, further comprising: When the SoE is equal to or greater than the boundary point A or the cumulative driving energy is less than the boundary point A', selecting the terrain driving method as the first control cycle; And Controlling the vehicle to drive in the EV mode in response to the first control cycle.

6. The method according to claim 5, further comprising: Defining at least one of a boundary point B based on the SoE and a boundary point B' based on the cumulative driving energy, where the SoE is the SoE available based on the current SoC and voltage according to the terrain driving method; Wherein the boundary point B is less than the boundary point A, and the boundary point B' is greater than the boundary point A'.

7. The method according to claim 6, wherein Determining the terrain driving method includes: Recalculating the cumulative driving energy from the beginning; When the SoE is equal to or greater than the boundary point B or the recalculated cumulative driving energy is less than the boundary point B', selecting the terrain driving method as the second control cycle; and Controlling the vehicle to drive in the series EV mode in response to the second control cycle.

8. The method according to claim 6, wherein Determining the terrain driving method includes: When the SoE is less than the boundary point B or the recalculated cumulative driving energy is greater than the boundary point B', selecting the terrain driving method as the third control cycle; and Changing the required torque in response to the third control cycle to reduce the required torque and power load of the vehicle.

9. The method according to claim 1, wherein Determining the terrain driving method includes: Judging whether the vehicle escapes from a steep road based on the speeds of the four wheels of the vehicle and the vehicle speed.

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

11. A terrain driving mode control device for a hybrid vehicle, comprising: A required torque determiner that defines a required torque for driving the vehicle according to a driver's demand and a driving road environment; A required torque differentiator that differentiates the required torque in response to a terrain driving mode; An accumulated driving energy calculator that calculates, based on the differentiated required torque, the accumulated driving energy starting from a running time point in the terrain driving mode; And An electric vehicle / hybrid vehicle driving mode determiner, i.e., an EV / HEV driving mode determiner, that determines a terrain driving method based on the calculated accumulated driving energy and an energy state, i.e., SoE, considering a state of charge, i.e., SoC, and a voltage condition of a battery unit.

12. The terrain driving mode control device according to claim 11, wherein The EV / HEV driving mode determiner defines at least one of a boundary point A based on the SoE and a boundary point A' based on the accumulated driving energy, and determines whether the SoE is less than the boundary point A or whether the accumulated driving energy is greater than the boundary point A'.

13. The terrain driving mode control device according to claim 12, wherein The EV / HEV driving mode determiner defines a boundary point based on the accumulated driving energy in consideration of at least one of a road environment, a driving habit, and battery charging and discharging characteristics.

14. The terrain driving mode control device according to claim 12, wherein The EV / HEV driving mode determiner defines the SoE at a time point when the vehicle switches from EV driving to series EV driving according to the terrain driving method as the boundary point A.

15. The terrain driving mode control device according to claim 14, wherein When the SoE is equal to or greater than the boundary point A or the accumulated driving energy is less than the boundary point A', the EV / HEV driving mode determiner selects the terrain driving method for a first control period, and In response to the first control period, the EV / HEV driving mode determiner controls the vehicle to drive in the EV mode.

16. The terrain driving mode control device according to claim 15, wherein The EV / HEV driving mode determiner defines at least one of a boundary point B based on the SoE and a boundary point B' based on the accumulated driving energy, the SoE being the SoE available based on a current SoC and voltage according to the terrain driving method, and The boundary point B is less than the boundary point A, and the boundary point B' is greater than the boundary point A'.

17. The terrain driving mode control device according to claim 16, wherein The EV / HEV driving mode determiner recalculates the accumulated driving energy from the beginning. When the SoE is equal to or greater than the boundary point B or the recalculated cumulative driving energy is less than the boundary point B', the EV / HEV driving mode determiner selects the terrain driving method for the second control period, and In response to the second control period, the EV / HEV driving mode determiner controls the vehicle to drive in a series EV mode.

18. The terrain driving mode control device according to claim 16, wherein When the SoE is less than the boundary point B or the recalculated cumulative driving energy is greater than the boundary point B', the EV / HEV driving mode determiner selects the terrain driving method for the third control period, and In response to the third control period, the EV / HEV driving mode determiner changes the demand torque to reduce the demand torque and electrical load of the vehicle.

19. The terrain driving mode control device according to claim 11, wherein The EV / HEV driving mode determiner determines whether the vehicle escapes from a steep road based on the speeds of the four wheels of the vehicle and the vehicle speed.

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