Hybrid electric vehicle

Abstract

To enable efficient consumption of a battery residual charge while assuring a travel on electricity in a specific section.SOLUTION: A control apparatus of a hybrid electric vehicle executes: first travel support control for creating a travel plan in which either of a charge consumption mode where a battery residual charge is not maintained and a charge maintaining mode where the battery residual charge is maintained is allocated to each of individual sections on a planned travel route on the basis of route information up to a destination and the battery residual charge; and second travel support control for requiring the charge maintaining mode in a case where a necessary residual charge for completing a travel on electricity throughout a specific section is not secured while traveling in a section prior to the specific section in which the travel on electricity is recommended. The requirement for the charge maintaining mode by the second travel support control is given priority over the travel plan. Allocation of the travel mode by the travel plan is executed on the basis of the route information and the battery residual charge and, in addition, on the basis of a requirement for allocating the charge consumption mode to the specific section.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a hybrid electric vehicle.

Background Art

[0002] Patent Document 1 discloses a control device for a hybrid vehicle. This control device is configured to assign an HV driving section or an EV driving section for each section based on the driving load of each section on the driving route.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a hybrid electric vehicle, it is conceivable to provide the following first and second driving support controls as controls for assisting vehicle driving to a destination. That is, the first driving support control generates a driving plan for assigning, to each section on the planned driving route to the destination, either a charging consumption mode that does not maintain the remaining battery level or a charging maintenance mode that maintains the remaining battery level, based on the route information to the destination and the remaining battery level. The second driving support control requests the charging maintenance mode when the necessary remaining battery level for traveling through a specific section by electric driving is not secured during traveling in a section before the specific section where electric driving is recommended.

[0005] The second driving support control described above does not switch driving modes to efficiently consume the remaining battery power while driving along the planned route, but rather requests a charge maintenance mode in response to a determination that the required battery power cannot be secured. Therefore, there is a concern that if the second driving support control is simply prioritized when the first and second driving support controls are executed simultaneously, there may be situations where the remaining battery power cannot be consumed efficiently.

[0006] This disclosure has been made in view of the above-mentioned issues, and its purpose is to enable a hybrid electric vehicle equipped with the above-mentioned first and second driving support controls to reliably perform electric driving in the above-mentioned specific section while efficiently consuming the remaining battery charge. [Means for solving the problem]

[0007] The hybrid electric vehicle according to this disclosure comprises a powertrain, a battery, and a control device. The powertrain is configured to perform hybrid driving and power generation through the cooperation of an internal combustion engine and one or more electric motors, and electric driving performed by one or more electric motors without operating the internal combustion engine. The battery exchanges power with the powertrain. The control device is configured to perform first and second driving support control. The first driving support control generates a driving plan that assigns either a charging consumption mode that does not maintain battery charge or a charging maintenance mode that maintains battery charge to each section of the planned driving route to the destination, based on route information to the destination and the battery charge level. The second driving support control requests the charging maintenance mode if the necessary battery charge to complete a specific section by electric driving is not secured while driving in a section preceding a specific section where electric driving is recommended. The request for the charging maintenance mode by the second driving support control takes precedence over the driving plan. The assignment of driving modes based on the driving plan is carried out based on route information and battery level, as well as requests to assign specific sections to the charging / consumption mode. [Effects of the Invention]

[0008] According to this disclosure, by prioritizing the charge maintenance mode request by the second driving support control over the driving plan of the first driving support control, it is possible to ensure that electric driving is reliably performed in a specific section. Furthermore, since the driving plan is executed in the first driving support control based on the request to assign the specific section to the charge consumption mode, the battery charge can be consumed efficiently. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram schematically shows the configuration of a hybrid electric vehicle according to an embodiment. [Figure 2] This diagram illustrates the challenges that arise when the first driving support control (control C1) and the second driving support control (control C2) operate simultaneously. [Figure 3] This diagram illustrates an example of the operation of an embodiment when control C1 and control C2 are operating simultaneously. [Figure 4] This flowchart shows the processing related to control C1 according to the embodiment. [Figure 5] This diagram shows specific examples A and B of the CD priority used in step S112. [Figure 6] This diagram illustrates the effect of prioritizing CD mode over specific section X when assigning downhill sections. [Modes for carrying out the invention]

[0010] 1. Example configuration of a hybrid electric vehicle (HEV) Figure 1 is a schematic diagram showing the configuration of a hybrid electric vehicle 1 according to an embodiment. The hybrid electric vehicle 1 comprises a powertrain 10, a control device 20, and an HMI (Human Machine Interface) device 30. The control device 20 includes a vehicle control ECU (Electronic Control Unit) 22 and a navigation ECU (Navigation ECU) 24.

[0011] The powertrain 10 includes an internal combustion engine 12, one or more (e.g., two) electric motors 14, and a battery 16, and is configured to perform hybrid driving (HEV driving) and power generation through the cooperation of the internal combustion engine 12 and the electric motors 14, and electric driving (BEV driving) performed by the electric motors 14 without operating the internal combustion engine 12. The battery 16 exchanges power with the powertrain 10, and more specifically with the electric motors 14. Specifically, the battery 16 is charged by the power generated by the electric motors 14 and discharged by the power consumed by the electric motors 14. The hybrid system of the vehicle 1 is not particularly limited and can be, for example, a series-parallel system, a parallel system, or a series system. More specifically, the vehicle 1 is an externally rechargeable plug-in hybrid electric vehicle (PHEV), but does not necessarily have to be configured to be externally rechargeable.

[0012] The vehicle control ECU 22 includes a processor and a memory device. The vehicle control ECU 22 receives sensor signals from sensors 26 attached to the vehicle 1 and outputs operation signals to the powertrain 10. The memory device stores various control programs for controlling the powertrain 10. The processor reads and executes the control programs from the memory device, thereby realizing various controls related to the powertrain 10. The sensors 26 include various sensors used for controlling the powertrain 10, such as a vehicle speed sensor, an accelerator position sensor, and a battery level sensor. The accelerator position sensor detects the amount of accelerator pedal operation (depression). The battery level sensor detects the remaining charge of the battery 16 (battery charge). In the following description, the battery charge is also referred to as SOC (State of Charge).

[0013] The Navi ECU24 is equipped with a processor and memory. The Navi ECU24 is configured to communicate with external systems via a wireless communication network and can acquire various data from external systems.

[0014] For example, the navigation ECU 24 obtains the current position of vehicle 1 using GNSS (Global Navigation Satellite System). Furthermore, the navigation ECU 24 can pinpoint the current position of vehicle 1 on a map by obtaining map information from, for example, an external server. The map information here includes information on specific service areas (SAs) where BEV driving, i.e., non-operation of the internal combustion engine 12, is recommended, and geographical information (e.g., speed limits, distance, and road type). Specific service areas are, for example, low-emission zones where the operation of vehicle 1 with the internal combustion engine 12 is restricted. The navigation ECU 24 can also obtain various traffic information from a traffic information center, such as congestion information, regulatory information, and traffic accident information. The navigation ECU 24 can notify the user of vehicle 1 of such various information using the HMI device 30. The HMI device 30 includes, for example, an output unit and an input unit installed inside the cabin of vehicle 1. The output unit includes a display unit, for example, a navigation system display or a meter installed on the instrument panel. The output section may include a speaker. The input section may be a touch panel or switches.

[0015] The navigation ECU 24 can also accept user input via the HMI device 30. For example, when a user operates the HMI device 30 and inputs a destination, the navigation ECU 24 creates a planned driving route PR from the vehicle 1's current location to the destination, displays it on the HMI device 30, and provides route guidance. In addition, the specific area SA may be arbitrarily set by the user operating the HMI device 30, for example.

[0016] Furthermore, the navigation ECU24 can calculate the required driving power PW and section driving energy E needed to travel through each section (section S) of the planned driving route PR, based on at least one of past driving data and information such as the type of road surface or gradient included in the map information. The navigation ECU24 can also calculate the required energy Esum needed to complete the planned driving route PR by integrating the driving energy E of each section S. In addition, the navigation ECU24 can also calculate the required energy Eev needed to travel through the "specific section X" described later using BEV driving.

[0017] The navigation ECU24 is connected to the vehicle control ECU22 via, for example, CAN (Controller Area Network) communication. This allows the vehicle control ECU22 to obtain various information (route information), including the planned driving route PR and various information related to the planned driving route PR, from the navigation ECU24. The route information referred to here is information about the route ahead of the vehicle that is read in advance, and is therefore also referred to as "predictive information" below. More specifically, the predictive information includes information about each section S along the planned driving route PR. The predictive information includes, for example, the map information, traffic information, section vehicle speed, and required driving power PW.

[0018] 2. Vehicle Driving Control The control device 20 is configured to be able to execute "first driving support control" and "second driving support control" as vehicle driving support functions. The driving modes of the vehicle 1 include a charge depleting (CD) mode and a charge sustaining (CS) mode. The CD mode is a mode that does not maintain the state of charge (SOC), and is used when realizing BEV driving. More specifically, the CD mode is a mode of driving mainly with the power charged in the battery 16. The CS mode is a mode that maintains the SOC, and is used when realizing HEV driving. More specifically, the CS mode is a mode of operating the internal combustion engine 12 and the electric motor 14 so as to maintain the target SOC. Also, in addition to the CD mode and the CS mode, the driving mode of the vehicle 1 may include, for example, a charging mode. The charging mode is a mode of performing HEV driving to recover the SOC to a predetermined threshold value when the SOC is depleted.

[0019] 2-1. First Driving Support Control In the first driving support control (control C1), the control device 20 generates a driving plan TP that assigns either the CD mode or the CS mode to each section S on the planned driving route PR to the destination based on the route information (advance information) to the destination and the current SOC. Then, in control C1, the control device 20 controls the driving mode of each section S according to the generated driving plan TP. As a result, BEV driving and HEV driving are automatically switched.

[0020] More specifically, the assignment of the CD mode / CS mode to each section S by the above driving plan TP is executed so that the SOC is efficiently consumed during driving on the planned driving route PR. For example, the assignment is executed so as to use up the SOC in accordance with the arrival of the vehicle 1 at the destination based on the advance information of each section S together with the SOC at the time of generating the driving plan TP. The advance information includes, for example, driving load information (e.g., required driving power PW) and traffic information.

[0021] Additionally, the control device 20 may use the HMI device 30 to notify the user (driver or other passenger) of the distance traveled by the BEV during the execution of control C1 (electric driving distance). This allows the user to check the electric driving distance using the HMI device 30 upon arrival at the destination.

[0022] 2-2. Second Driving Assistance Control In the second driving support control (control C2), the control device 20 manages the State of Charge (SOC) so that the necessary battery charge (required SOCev) for driving through the specified section X in BEV mode is secured before entering the specified section X, if the specified section X exists on the planned driving route PR of vehicle 1 to the destination. The specified section X is the section S on the planned driving route PR included in the specified area SA mentioned above. The required SOCev is the SOC value corresponding to the required energy Eev mentioned above.

[0023] More specifically, the request for a driving mode by control C2 is made as follows: For a specific section X, the CD mode is requested. Then, while driving in section S before the specific section X, the control device 20 determines whether the required SOCev is secured. For example, this determination is made considering a predetermined margin α. That is, the determination is made based on whether the current SOC satisfies the required SOCev plus the margin α, which is called sufficient SOCevm (=SOCev+α). As a result, when the current SOC falls below sufficient SOCevm, in other words, when it can be determined that "the required SOCev is not secured when entering the specific section X", the CS mode is requested by control C2. Also, when the current SOC falls below the required SOCev while driving in section S before the specific section X, the charging mode is requested by control C2 in order to secure the required SOCev.

[0024] According to the control C2 described above, BEV driving and HEV driving are switched so that the necessary SOCev is secured before entering the specific section X. By monitoring the SOC before entering the specific section X with this control C2, BEV driving can be reliably performed in the specific section X.

[0025] 2-3. Details of assigning driving modes based on the driving plan TP Figure 2 illustrates the problems that arise when control C1 and control C2 operate simultaneously. Figure 2 corresponds to a comparative example in which these problems occur.

[0026] The travel plan TP0 (i.e., the request for control C1) for the comparative example of control C1 is generated at point P1. More specifically, the travel plan TP0 is generated based on the route information (look-ahead information) acquired at point P1 and the current SOC at point P1. According to the travel plan TP0, either CD mode or CS mode is assigned to each section S on the planned travel route PR1 to the destination. Figure 2 shows each CD planned section to which CD mode is assigned, and each CS planned section to which CS mode is assigned, according to the travel plan TP0. Each of these CD and CS sections consists of one or more sections S.

[0027] Furthermore, the planned driving route PR1 shown in Figure 2 includes a specific section X that is the focus of control C2. However, in the comparative example, the driving plan TP0 of control C1 is generated without any special consideration to enable BEV driving in this specific section X.

[0028] On the other hand, control C2 monitors the State of Charge (SOC) to ensure reliable BEV driving in a specific section X. Specifically, if the SOC at point P1 meets the required SOCevm (=SOCev + α), control C2 only requests that the specific section X be in CD mode. However, if the SOC falls below the required SOCevm between point P1 and the specific section X, control C2 requests CS mode to avoid the SOC falling below the required SOCev before entering the specific section X. In one example shown in Figure 2, such a request for CS mode is made at point P2. If the SOC at point P1 does not meet the required SOCevm (=SOCev + α) but does meet the required SOCev, control C2 requests CS mode from point P1 until entering the specific section X. Furthermore, if the SOC at point P1 does not meet the required SOCev, control C2 requests charging mode at point P1. Then, if the SOC recovers to a level exceeding the required SOCev, control C2 requests CS mode until entering a specific section X.

[0029] Figure 2 also shows the final requirements. These final requirements correspond to the driving mode ultimately required of the powertrain 10. Here, the final requirements are determined by mediating between the driving plan TP0 of control C1 and the requirements of control C2, such that the requirements of control C2 take precedence over the driving plan TP0 of control C1. As a result, the final requirements shown in Figure 2 are obtained. That is, in sections S where there are requirements of control C2, the final requirements are determined according to those requirements. And in sections S where there are no requirements of control C2, the final requirements are determined according to the driving plan TP0.

[0030] As already explained, unlike control C1, control C2 does not determine the CD mode / CS mode by considering the efficient consumption of SOC, but rather requests a driving mode purely to ensure that BEV driving can be reliably performed in a specific section X. Therefore, if the request of control C2 is simply prioritized when controls C1 and C2 are executed simultaneously, situations may arise where SOC cannot be consumed efficiently, as shown in the comparative example in Figure 2.

[0031] In other words, according to the final requirements for this comparative example, battery depletion occurs at point P3. When battery depletion occurs, the control device 20 automatically switches the driving mode to CS mode in order to perform HEV driving. Thus, according to the final requirements, the SOC is used up at an earlier time (point P3) compared to the driving plan TP0 of control C1. Furthermore, in this comparative example, the total electric driving distance on the planned driving route PR1 is also shorter than that of the driving plan TP0. The reason why the final requirements are inferior to the driving plan TP0 is as follows: In a specific section X where the CD mode was not assigned in the driving plan TP0, the CD mode is selected according to the requirements of control C2, which does not consider the efficient consumption of SOC. Furthermore, in section S1 where the CD mode is not assigned in the driving plan TP0, the CS mode is selected according to the requirements of control C2.

[0032] In view of the above-mentioned issues, in this embodiment, in order to ensure reliable BEV driving in a specific section X while efficiently consuming the State of Charge (SOC), the control device 20 performs the following processing. That is, in this embodiment as well, the request for CS mode by control C2 takes precedence over the driving plan TP of control C1. Furthermore, the assignment of CD mode / CS mode by the driving plan TP is performed based on route information (predictive information) and SOC, as well as a request to assign the specific section X to CD mode.

[0033] Figure 3 is a diagram illustrating an example of the operation of an embodiment when control C1 and control C2 are operating simultaneously. In Figure 3, the same planned travel path PR1 as in Figure 2 is shown as an example.

[0034] Unlike the comparative example shown in Figure 2, the driving plan TP1 of control C1 shown in Figure 3 takes a specific section X into consideration. Specifically, specific section X is treated as one of the "CD priority sections" to which CD mode is preferentially assigned. As a result, in the example shown in Figure 3, CD mode is actually assigned to specific section X. Specific examples of setting CD priority sections will be described later, along with Figures 5(A) and 5(B).

[0035] When a travel plan TP1 is generated based on a request to assign a specific section X to CD mode, it becomes possible to assign section S, which was assigned to CD mode in a travel plan TP0 generated without such a request, to CS mode. Specifically, for example, a section S with a relatively high driving load within the CD planned section in travel plan TP0 can be assigned to CS mode instead of the specific section X. In the example of travel plan TP1 shown in Figure 3, a part of section S2 and section S3 correspond to the sections to which CS mode is assigned in this way. This makes it possible to generate a travel plan TP1 that efficiently consumes SOC while assigning CD mode to the specific section X, taking into account the entire planned travel route PR1. This leads to an improvement in electric driving range.

[0036] Furthermore, similar to the comparative example shown in Figure 2, in the final request according to this embodiment, the request of control C2 takes precedence over the driving plan TP0 of control C1. However, in the example shown in Figure 3, the driving plan TP1 of control C1 remains the final request. This is because no request for CS mode has been issued from control C2. On the other hand, unlike this example, due to errors in control C1, such as errors in predicting the planned energy requirement Esum, the SOC may fall below the above-mentioned sufficient SOCevm before entering the specific section X. However, in this embodiment, if the SOC falls below the sufficient SOCevm in this way, control C2 requests CS mode. And this request for CS mode takes precedence over the driving plan TP1. That is, in accordance with this request, the driving mode for the CD planned section of the driving plan TP1 is changed to CS mode. Therefore, even if the above-mentioned decrease in SOC occurs, control C2 guarantees that BEV driving will be performed in the specific section X.

[0037] Next, Figure 4 is a flowchart showing the processing related to control C1 according to the embodiment. The processing in this flowchart is started when the system of vehicle 1 is started and is executed by the control device 20 (more specifically, for example, the cooperation of vehicle control ECU 22 and navigation ECU 24). Figure 4 also shows the processing when control C1 is executed under conditions in which control C2 is executed.

[0038] In step S100, the control device 20 determines whether the start conditions for control C1 (in other words, the start conditions for driving assistance) are met. Specifically, the start conditions include, for example, that the switch requesting control C1 is ON, that route guidance based on the user's request has started, that vehicle 1 is on the planned driving route PR, that the SOC is above a predetermined threshold, and that no abnormality has occurred in vehicle 1. If the result of this determination is Yes, the process proceeds to step S102.

[0039] In step S102, the control device 20 determines whether the look-ahead information used for control C1 has been updated. If the look-ahead information has been updated, the process proceeds to step S104. On the other hand, if the look-ahead information has not been updated, the process proceeds to step S118.

[0040] In step S104, the control device 20 calculates the section travel energy (energy consumed) E and the sum (required energy) Esum for each section S on the planned travel route PR based on the current lookahead information.

[0041] Next, in step S106, the control device 20 determines whether the sum Esum calculated in step S104 is greater than the value obtained by adding a predetermined margin β to the current SOC. If the result of this determination is Yes, that is, if it is determined that the vehicle cannot reach its destination using only BEV power, the process proceeds to step S108.

[0042] In step S108, the control device 20 determines whether control C2 is active and whether a specific section X exists on the planned travel route PR. If the result of this determination is Yes, the control device 20 assigns the specific section X to a CD priority section in step S110. More specifically, the storage device of the control device 20 stores CD priority information used in the travel plan TP of control C1 (see, for example, Figure 5(A) or 5(B)). Assigning the specific section X to a CD priority section in step S110 is equivalent to using the CD priority information, including the CD priority of the specific section X, to generate the travel plan TP. On the other hand, if the result of this determination is No, the process proceeds directly to step S112.

[0043] Next, in step S112, the control device 20 generates a travel plan TP that assigns either CD mode or CS mode to each section S on the planned travel route PR, based on the current look-ahead information, the current SOC, and the CD priority.

[0044] Figures 5(A) and 5(B) show specific examples A and B of the CD priority used in step S112, respectively. Here, "CD priority" refers to the priority, or more specifically, the priority, of assigning the CD mode to each section S included in the planned travel route PR in control C1. The smaller the CD priority number, the higher the CD priority. Furthermore, specific examples A and B show the setting of the CD priority when a specific section X is included in the CD priority section. On the other hand, the setting of the CD priority when a specific section X is not included in the CD priority section is equivalent to specific example A with the specific section X removed.

[0045] (Specific example A) First, in specific example A, all sections S of the planned driving route PR are classified into six categories based on CD priority. Specifically, sections S with CD priority 1 are off-road sections and the first short-distance section during replanning. Off-road sections are assumed to be low-speed and low-load sections such as parking lots. The first short-distance section during replanning is the short distance from a point where the driving plan TP is updated (replanned) while driving in a section S to which CD mode is assigned, to the end of that section S. The driving plan TP is updated in accordance with the update of predictive information, which takes place at a predetermined interval (e.g., 1 minute). In other words, replanning is performed. In order to avoid the driving mode switching solely for passing through the first short-distance section due to CS mode being assigned to the first short-distance section during replanning, the CD priority of the first short-distance section is set to 1.

[0046] Section S with CD priority 2 is a low-load section. A low-load section is a section S in which the driving load (e.g., required driving power PW) is below a predetermined threshold. Low-load sections include, for example, sections between urban areas and downhill sections. By increasing the CD priority of such low-load sections compared to congested sections, an improvement in electric driving range can be expected. Whether or not section S is a downhill section can be determined, for example, based on map information included in the predictive information.

[0047] Section S with CD priority 3 consists of congested sections and specific section X. Since the internal combustion engine 12 is inefficient during congested driving, fuel efficiency can be improved by increasing the CD priority of congested sections. Furthermore, by moderately increasing the CD priority of specific section X, it is possible to suppress the request for CS mode from control C2 while suitably achieving both ensuring BEV driving in specific section X and an efficient driving plan TP in control C1. Whether or not section S is a congested section can be determined, for example, based on traffic information included in the predictive information.

[0048] Section S with CD priority 4 is a general section, in other words, the remaining section S that does not fall under any of the sections S with CD priority 1 to 3 or the sections S with CD priority 5 and 6. In specific example A, sections S with CD priority 1 to 3 correspond to CD priority sections where BEV driving is desired to be prioritized. Sections S with CD priority 5 and 6, as explained below, correspond to CS priority sections where HEV driving is desired to be prioritized.

[0049] Section S with CD priority 5 consists of high-load sections and exceptional integrated high-load sections. A high-load section is a section S where the driving load is higher than a predetermined threshold, such as a highway. By lowering the CD priority of such high-load sections, highly efficient HEV driving using CS mode can be expected in high-load sections. Furthermore, an improvement in the electric driving range along the planned driving route PR can be expected compared to when BEV driving is performed in high-load sections. An exceptional integrated high-load section is a section S that has been integrated as a high-load section in cases where the planned driving route PR is long, and is included in section S with CD priority 5 for the same purpose as the high-load sections described above. Note that, in order to reduce the number of sections S due to limitations of memory and communication, such integration of section S is carried out by integrating multiple sections S closer to the end of the planned driving route PR into two sections, namely exceptional integrated high-load sections and exceptional integrated high-load sections, based on the level of driving load. An exceptional integrated low-load section is included, for example, in a general section with CD priority 4.

[0050] The sections S with CD priority 6 are the end margin section, the emergency HEV section, and the second short-distance section for replanning. More specifically, the driving plan TP by control C1 may be generated such that the SOC is consumed to below a predetermined threshold before the end margin section, which is one or more sections S near the destination, while the destination is the endpoint. The reason for this is to more reliably meet the user's expectation that the SOC will be consumed appropriately by the time of arrival at the destination, in other words, that the SOC will be used up. The emergency HEV section is a section S located before a downhill section where a significant recovery of SOC can be expected through energy regeneration during vehicle deceleration, when the SOC at the time of generation of the driving plan TP is below a predetermined threshold. Such an emergency HEV section may be provided to prevent battery depletion before entering the downhill section. Furthermore, the second short-distance section, unlike the first short-distance section mentioned above, is the short distance from a point where the driving plan TP is updated (replanned) while driving in section S to which CS mode is assigned, to the end of section S. In order to avoid switching the driving mode solely for this second short-distance section, the CD priority for this second short-distance section is set to 6.

[0051] Next, Specific Example B differs from Specific Example A in the following respects. In Specific Example B, in order to differentiate the CD priority of a specific section X from the CD priority of a congested section, all sections S of the planned route PR are classified into seven categories according to their CD priority. In other words, in Specific Example B, the CD priority of a specific section X is 3, and the CD priority of a congested section is 4. In Specific Example B, each section S with a CD priority from 1 to 4 corresponds to a CD priority section.

[0052] In step S112 of Figure 4, the control device 20 identifies the CD planned section according to the travel plan TP of control C1, based on the current SOC and CD priority (specific example A or B). Then, the control device 20 assigns the CD mode to the section S that was not assigned to the CD planned section.

[0053] More specifically, in order to identify the CD planning section, the control device 20 accumulates the running energy E of each section S within the planned route PR in order of CD priority. Then, within the range where the accumulated value of running energy E does not exceed the current SOC, the control device 20 identifies the section S with the maximum number of entries subject to the accumulation as the CD planning section. Through this process, within the range where the accumulated value of running energy E of the CD planning section does not exceed the current SOC, each section S within the planned route PR can be assigned to CD mode in order of CD priority. In addition, depending on the current SOC, it is not necessarily the case that all CD priority sections (for example, sections S with CD priority 1 to 3 in Figure 5(A)) will be assigned to CD mode. Also, between two sections S with the same CD priority, for example, the section S with the lower running load will be preferentially included in the above accumulation, that is, preferentially assigned to CD mode.

[0054] On the other hand, if the result of step S106 is No, that is, if it is determined that the destination can be reached using only BEV driving, the process proceeds to step S114. In step S114, the control device 20 generates a driving plan TP so as to assign CD mode to all sections S on the planned driving route PR.

[0055] In step S116, following step S112 or S114, the control device 20 mediates the travel plan TP of control C1 processed in steps S104 to S114 with the request from control C2 to determine the final request. The control device 20 then controls the travel mode in accordance with the determined final request. Specifically, as shown in the example in Figure 3, if there is no request for a CS mode from control C2, the travel plan TP remains the final request. If there is a request for a CS mode from control C2, the travel plan TP modified according to that request corresponds to the final request.

[0056] Next, in step S118, the control device 20 determines whether the termination conditions of control C1 are met. Specifically, the termination conditions include, for example, that route guidance has been stopped or terminated, that vehicle 1 has deviated from the planned driving route PR, that the battery has been depleted, or that an abnormality has occurred in vehicle 1. As long as the termination conditions are not met, the processes from step S102 onward are repeatedly executed. On the other hand, if the termination conditions are met, the process shown in Figure 4 is terminated.

[0057] 3. Effects As described above, according to this embodiment, the function of control C2 ensures that BEV driving can be reliably performed in a specific section X, while control C1, which generates a driving plan TP based on a request to assign the specific section X to CD mode, enables efficient consumption of SOC. This leads to an improvement in the electric driving distance in the planned driving route PR.

[0058] Furthermore, according to this embodiment, as illustrated in Figures 5(A) and 5(B), the CD priority of a specific section X is set to be lower than the CD priority of a low-load section. This makes it easier for the CD mode to be assigned to a low-load section. When the driving load of a certain section S is low, the SOC consumed by driving in that section S decreases. This leads to an improvement in the electric driving distance in the planned driving route PR. Therefore, by setting the CD priority in this way, the user's expectation of improved electric driving distance through the use of control C1 can be better met. In addition, according to this embodiment, control C2 ensures that BEV driving can be reliably performed in a specific section X. Therefore, by setting the CD priority in this way, it is possible to appropriately lower the CD priority of a specific section X in order to improve the electric driving distance while reliably performing BEV driving in that specific section X.

[0059] Furthermore, according to this embodiment, the low-load section includes a downhill section. This provides the effects described below with reference to Figure 6. Figure 6(A) shows the operation of control example A, where the CD priority of a specific section X is higher than the CD priority of the downhill section. Figure 6(B) shows the operation of control example B, where the CD priority of a specific section X is lower than the CD priority of the downhill section. In control examples A and B, the driving plans TP2 and TP3 of control C1 are generated at point P4. Also, there is a downhill section before the specific section X. The SOC at point P4 is 200Wh. The driving energy E of the downhill section is -600Wh. That is, in the downhill section, the energy regeneration effect performed by the powertrain 10 is taken into consideration, and the driving energy E becomes a negative value. The driving energy E of the specific section X (i.e., required SOCev) is 200Wh.

[0060] First, let's explain control example A shown in Figure 6(A). The State of Control (SOC) at the time of generating the travel plan TP2 in control C1 (i.e., at point P4) is 200 Wh, the same as the travel energy E of the specific section X. In control example A, the specific section X is preferentially assigned to CD mode over the downhill section, making it impossible to assign the downhill section to CD mode. Therefore, according to the travel plan TP2, CD mode is assigned to the specific section X, and CS mode is assigned to the other section S, which includes the downhill section.

[0061] In control example A, control C2 requests CD mode for a specific section X. Here, the SOC at point P4 does not meet the required SOCevm but is equal to the required SOCevm. Therefore, control C2 requests CS mode at point P4. This request for CS mode continues until point P5, when the SOC recovers to the required SOCevm through energy regeneration during downhill driving. In other words, no requests are made by control C2 between point P5 and point P6, the entry point to specific section X.

[0062] In control example A, even in the final request, CS mode is requested until entering a specific section X, and CD mode is requested in section X. With such control example A, the requirement of control C2, which is to enable BEV driving in specific section X, can be met. However, BEV driving cannot be performed in downhill sections. In other words, it is not possible to extend the electric driving range by utilizing downhill sections. For this reason, it can be said that control example A does not adequately meet the user's expectation of improving the electric driving range by using control C1.

[0063] In contrast, in control example B shown in Figure 6(B), in the driving plan TP3 of control C1, the downhill section is assigned to CD mode with priority over the specific section X. According to the process in step S112 described above, in order to identify the CD planned section, the driving energy E of each section S is accumulated in order of CD priority. In control example B, the value obtained by accumulating the driving energy E in the order of the downhill section and the specific section X is -400Wh, which is below the SOC of point P4, which is 200Wh. Therefore, both the downhill section and the specific section X are assigned to CD mode.

[0064] Furthermore, the requirements of control C2 are based solely on a comparison between the current SOC and the sufficient SOCevm or required SOCev. For this reason, the requirements of control C2 in control example B are the same as those in control example A.

[0065] In control example B, the final request is as shown in Figure 6(B), as a result of the control C2 request taking priority over the travel plan TP3. In other words, compared to control example A, in control example B, the CD mode is assigned from point P5 where the CS request of control C2 disappears to point P6 where the vehicle enters specific section X. As a result, BEV driving is performed for most of the downhill section. Therefore, according to control example B, the user's expectation of improved electric driving range through the use of control C1 can be better met compared to control example A.

[0066] Furthermore, according to this embodiment, as shown in specific example B in Figure 5(B), the CD priority of a specific section X may be set higher than the CD priority of a congested section. Here, if the CD priority is the same between the congested section and the specific section X, as in specific example A, depending on the SOC when generating the driving plan TP, there may be cases where the CD mode is assigned to the congested section but not to the specific section X. In such cases, a request for CS mode from control C2 may result in HEV driving in a section S that is less efficient than the CS planned section based on the driving plan TP (for example, a low-load section). In contrast, according to specific example B, it becomes possible to perform driving plan TP while suppressing such requests for CS mode from control C2. [Explanation of symbols]

[0067] 1 Hybrid electric vehicle, 10 Powertrain, 12 Internal combustion engine, 14 Electric motor, 16 Battery, 20 Control unit, 26 Sensors, 30 HMI device

Claims

1. A powertrain capable of performing hybrid driving and power generation through the cooperation of an internal combustion engine and one or more electric motors, and electric driving performed by the one or more electric motors without operating the internal combustion engine, A battery that exchanges power with the aforementioned powertrain, A control device that performs first and second driving support control, Equipped with, The first driving support control generates a driving plan that assigns either a charging consumption mode that does not maintain the battery level or a charging maintenance mode that maintains the battery level to each section of the planned driving route to the destination, based on the route information to the destination and the remaining battery level. The second driving support control requests the charge maintenance mode if, while driving in the section preceding the specific section where electric driving is recommended, the necessary battery charge for driving the specific section using electric driving is not secured. The request for the charge maintenance mode by the second driving support control takes precedence over the driving plan. The assignment of the driving mode according to the aforementioned driving plan is performed based on the route information and the remaining battery level, and also takes into consideration the specific section as one of the priority sections to which the charging consumption mode is preferentially assigned. In the first driving support control, the priority for assigning the charging consumption mode to the specific section is lower than the priority for assigning the charging consumption mode to the low-load section where the driving load is below a threshold, and higher than the priority for assigning the charging consumption mode to the congested section. Hybrid electric vehicle.

2. The aforementioned low-load section is a section that includes a downhill slope. The hybrid electric vehicle according to claim 1.

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