Vehicle energy control method and vehicle energy control device

Abstract

To improve run-through performance in a severe travelling scene.SOLUTION: An energy control method of a vehicle V is used in the vehicle V which has: an engine 1; a battery 3 which is charged by an MG2 and an MG2 which are driven by the engine 1 to generate electric power; and an MG4 that drives a drive wheel 6 by the electric power supplied from the battery 3 or the electric power generated by the MG2. The method includes: enhancing the output of the engine 1 when the vehicle starts to travel in a severe travelling section including a section in which the vehicle keeps on travelling with electric power consumptions exceeding the electric amount of electric power that can be generated by the MG2; supplying the electric energy generated by the MG2 to the MG4 on a priority basis, while the vehicle travels in the sever travelling section; and supplying excess generated electric energy which is not consumed by the MG4 while the vehicle is traveling in the sever travelling section, as electric energy. to the battery 3.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to vehicle energy control. [Background technology]

[0002] Patent Document 1 discloses a technique for reducing an efficiency index and keeping a high state of charge of a battery in anticipation of the amount of energy consumed when traveling uphill based on uphill information of a vehicle's travel route. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3624839 Summary of the Invention [Problem to be solved by the invention]

[0004] Vehicles often encounter extremely challenging driving situations, such as uphill roads, which can only be negotiated by increasing the battery charge state as much as possible while driving. In these situations, increasing the battery charge state before reaching the situation may not provide sufficient energy to cover the energy consumed during the situation. As a result, the battery charge state may drop excessively during driving in the situation, making it necessary to limit the power of the drive motor or stop the vehicle to charge the battery before the situation is reached.

[0005] The present invention has been made in view of such problems, and aims to improve the driving performance in severe driving situations. [Means for solving the problem]

[0006] A vehicle energy control method according to one aspect of the present invention includes increasing engine output when the vehicle starts traveling through a severe driving section that includes a section in which a first motor, which is driven by the engine to generate electricity, continues to travel at an amount of power consumption that exceeds the amount of power that the first motor can generate. The method also includes preferentially supplying the generated energy of the first motor to a second motor that drives the drive wheels while traveling through the severe driving section, and supplying the surplus generated energy that is not consumed by the second motor to a battery as electric energy. The method further includes predicting an energy consumption rate of the second motor in the severe driving section before starting driving in the severe driving section, and setting the engine output higher as the predicted energy consumption rate increases.

[0007] According to another aspect of the present invention, there is provided a vehicle energy control device corresponding to the above vehicle energy control method. [Effects of the Invention]

[0008] According to these aspects, engine output is increased when starting to travel through a severe driving section, and generated energy is preferentially supplied to the second motor while traveling through the severe driving section. This reduces battery power consumption even while traveling through the severe driving section. Furthermore, surplus generated energy is supplied to the battery as electrical energy, so the battery state of charge can be maximized even while traveling through the severe driving section. As a result, excessive decreases in the battery state of charge are suppressed, and there is less need to limit the power of the drive motor or charge the battery while the vehicle is stopped, improving the vehicle's ability to traverse severe driving conditions. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a drive system of a vehicle. [Figure 2] FIG. 4 is a flowchart showing an example of control performed by a controller. [Figure 3] FIG. 10 is a diagram illustrating an example of a method for setting a severe driving section. [Figure 4] FIG. 4 is a flowchart illustrating an example of normal operation control. [Figure 5] FIG. 10 is a diagram showing a change in engine output from the start of travel in a severe travel section. [Figure 6]FIG. 10 is a diagram showing engine output changes in the case of a comparative example. [Figure 7] FIG. 4 is a diagram illustrating a first setting method for engine output. [Figure 8] FIG. 10 is a diagram illustrating a second setting method for the engine output. [Figure 9] FIG. 10 is a diagram illustrating the effect of severe scene running time. [Figure 10] FIG. 10 is a diagram illustrating the effect of a battery cooling request. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0011] 1 is a schematic diagram of the drive system of a vehicle V. The vehicle V includes an engine 1 consisting of an internal combustion engine, a first motor generator 2 (hereinafter referred to as MG2) as a first motor, a battery 3, a second motor generator 4 (hereinafter referred to as MG4) as a second motor serving as a drive source for traveling, an inverter 5, drive wheels 6, a gear mechanism 7 as a power transmission mechanism for transmitting power between the engine 1 and MG2, a gear mechanism 8 as a power transmission mechanism for transmitting power between the MG4 and the drive wheels 6, and a controller 10 as a control device. The vehicle V of this embodiment is a series-type hybrid vehicle in which the power of the engine 1 is used only for generating electricity, and the power of the MG4 is used to drive the drive wheels 6 and for regenerating electricity.

[0012] MG2 is a three-phase AC permanent magnet synchronous motor mounted as both a generator and an electric motor. Specifically, when MG2 receives rotational power from engine 1, it functions as a generator. When MG2 receives power from battery 3, it can function as a starter motor for engine 1 and as a motoring motor that rotates and drives engine 1.

[0013] The battery 3 may be, for example, an all-solid-state battery or semi-solid-state battery using a solid electrolyte, or a lithium-ion battery using an electrolyte solution, with the charge rate increased from the conventional 2C to approximately 6C by improving the negative electrode material with graphene as a conductive additive. For safety reasons, batteries using an electrolyte solution (organic solvent), such as lithium-ion batteries, have a maximum charge capacity (approximately 90%) that is a certain safety factor (e.g., approximately 10%) relative to the charge capacity (assumed to be 100%) when the battery voltage reaches the upper limit for safe repeated charging and discharging. In contrast, all-solid-state batteries, semi-solid-state batteries, or lithium-ion batteries using the above-mentioned electrolyte solution with an increased charge rate can achieve a maximum charge capacity (100%) that is approximately the same as the charge capacity when the battery voltage reaches the upper limit for safe repeated charging and discharging. Therefore, using the above-mentioned battery as the battery 3 allows for maximum utilization of the battery capacity. The battery 3 is charged with power generated by the MG2 and power regenerated by the MG4, and supplies the charged power to the MG4 or the MG2.

[0014] The SOC (State Of Charge) of the battery 3 is detected by an SOC sensor 3a and transmitted to the controller 10. The SOC indicates the battery charge state and is represented by a charging rate R in this embodiment. The controller 10 controls the charging of the battery 3 based on the SOC, the temperature of the battery 3, and the like. When the SOC of the battery 3 drops to the lower limit of the charging control, the controller 10 drives the engine 1. This drives the MG2, and power generated by the MG2 is supplied to the battery 3, charging the battery 3. When the SOC of the battery 3 rises to the upper limit of the charging control, the controller 10 stops the engine 1. This stops the MG2, and power generation by the MG2 stops.

[0015] The MG4 is a three-phase AC permanent magnet synchronous motor powered by the battery 3. The MG4 may be, for example, a wound field motor. The MG4 is driven by power supplied from the battery 3. The rotational power of the MG4 is transmitted to the drive wheels 6 via a gear mechanism 8, causing the vehicle V to move. The MG4 also has a regenerative function that generates power to charge the battery 3 when it receives rotational power from the drive wheels 6 during deceleration or braking of the vehicle V.

[0016] The inverter 5 includes a first inverter that controls MG2 and a second inverter that controls MG4, and connects MG2 and MG4 to the battery 3. The inverter 5 has the functions of converting the power of the battery 3 into three-phase AC and supplying it to MG2 and MG4, converting the power generated by MG2 and the regenerated power of MG4 into DC and supplying it to the battery 3, and exchanging power between MG2 and MG4 without going through the battery 3. The inverter 5 performs these functions based on commands from the controller 10, thereby exchanging power between the battery 3, MG2, and MG4.

[0017] The controller 10 is composed of one or more computers (microcomputers) equipped with a central processing unit (CPU), read-only memory (ROM), random access memory (RAM), and an input / output interface (I / O interface). The controller 10 performs integrated control of the engine 1, inverter 5 (MG2, MG4), etc. by executing a program stored in the ROM or RAM using the CPU. The program may be stored in a non-transitory storage medium such as a CD-ROM. In addition to the output signal from the SOC sensor 3a, the controller 10 receives the output signal from the rotation speed sensor 1a, the output signal from the MG4, information from a navigation system (not shown), and the like. The rotation speed Ne of the engine 1 is detected based on the output signal from the rotation speed sensor 1a. The information from the navigation system includes information on the current location of the vehicle V.

[0018] The driving scenarios of vehicle V include extremely severe driving scenarios, such as uphill roads, which can only be negotiated by increasing the SOC as much as possible while driving. In such scenarios, there is a concern that increasing the SOC before reaching the scenario may not provide sufficient energy for the energy consumption in the scenario. As a result, there is a concern that the SOC may drop excessively while driving in the scenario, which may require limiting the power of MG4 or stopping the vehicle to charge battery 3 before driving through the scenario.

[0019] In view of these circumstances, in this embodiment, the controller 10 is programmed to perform the control described below.

[0020] FIG. 2 is a flowchart showing an example of control performed by the controller 10. The controller 10 repeatedly executes the processing of the flowchart shown in FIG. 2. The control related to this flowchart is performed based on a program pre-stored in the controller 10. The same applies to FIG. 3, which will be described later. In step S1, the controller 10 detects the current location of the vehicle V based on information from the navigation system. In step S2, the controller 10 determines whether the vehicle V is traveling in a severe driving section. A severe driving section includes a section in which the MG2 continues to travel with an amount of power consumption that exceeds the amount of power it can generate, and the determination in step S2 can be made based on the current location of the vehicle V and information about the severe driving section. The severe driving section can be set, for example, as follows.

[0021] FIG. 3 is a diagram showing an example of a method for setting a severe driving section. FIG. 3 shows, for example, the change in power consumption W by MG4 when an uphill road is present along the driving route. Power consumption W1 is the same value as the power generated by engine 1 (MG2) at maximum, that is, the value at which the balance with the power generated at maximum is zero. When power consumption W by MG4 is equal to or greater than W1, even if engine 1 (MG2) generates power at maximum, the power generated by engine 1 (MG2) alone will not be enough to drive MG4. In this state, power from battery 3 will be used, and the charging rate R of battery 3 will decrease.

[0022] Therefore, in this embodiment, if it is predicted that the state in which the power consumption W of the MG4 is equal to or greater than W1, in other words, the state in which the vehicle V travels at an amount of electricity that exceeds the amount of power that can be generated by the MG2, will continue for a predetermined time, the travel section (between points C1 and C4) is determined to be a severe travel section. The predetermined time can be set in advance as a determination value for determining whether the travel section is a severe travel section. Note that, as shown in FIG. 3 , even if the power consumption W of the MG4 temporarily falls below W1 (for a predetermined time) (between points C2 and C3), if it is predicted that the power consumption by the MG4 will continue to be equal to or greater than W1 for a certain period of time, these travel sections are also determined to be severe travel sections. In other words, severe travel sections include travel sections in which the vehicle V travels at an amount of electricity that exceeds the amount of power that can be generated by the MG2, and travel sections in which such a state tends to continue. Furthermore, the power consumption W here may be the power consumption of the MG4 alone, or may be the total power consumption of the devices required to drive the vehicle V.

[0023] The above-described prediction and determination of severe driving sections can be performed, for example, by a navigation system when predicting a driving route. When predicting a severe driving section, in addition to the location of the severe driving section, the power consumption W, driving distance, and driving time are also predicted as information about the severe driving section. The information about the severe driving section may be set in advance in, for example, the navigation system. The information about the severe driving section may be stored in the navigation system, or, for example, in an external server of the vehicle V that can acquire information via the controller 10 or wireless communication. The determination of whether or not the vehicle is traveling through a severe driving section may also be performed by the navigation system, etc. In this case, the controller 10 can determine whether or not the vehicle is traveling through a severe driving section based on the determination result. The controller 10 may predict a severe driving section and determine whether or not the vehicle is traveling through a severe driving section by learning driving patterns rather than by using information from the navigation system.

[0024] Returning to FIG. 2 , in step S1, for example, SOC may be detected instead of the current location. In this case, in step S2, if the degree of decline in SOC (the amount of decline in SOC per unit time) exceeds a predetermined value and continues for a predetermined time or more, it can be determined that the vehicle is traveling in a severe driving section. The predetermined value is set in advance as a determination value for determining whether the power consumption W of MG4 exceeds the power generated by MG2 when maximum power is generated, and the predetermined time is set in advance as a determination value for determining that the vehicle is traveling in a severe driving section. In this case, in step S2, if the degree of decline in SOC continues to be equal to or less than the predetermined value and continues for a predetermined time or more, it is determined that the vehicle is not traveling in a severe driving section, that is, that the vehicle has left the severe driving section. This makes it possible to determine whether the vehicle is traveling in a severe driving section even when the navigation system cannot be used. The predetermined time for determining that the vehicle is not traveling in a severe driving section can be set to a value different from the predetermined time, for example, to be longer than the predetermined time for determining that the vehicle is traveling in a severe driving section.

[0025] In step S1, the driving state of vehicle V may be detected instead of the current location. The driving state of vehicle V may be, for example, the driving force of MG4. In this case, if the driving force of MG4 exceeds the required driving force for a predetermined period of time or more, it can be determined in step S2 that vehicle V is traveling in a severe driving section. The required driving force is the driving force of MG4 obtained by the power generated by MG2 when it generates maximum power, and the predetermined period of time can be set in the same way as when detecting SOC. The driving state of vehicle V may be, for example, the power consumption W of MG4. In this case, it can be determined in step S2 whether the power consumption W of MG4 exceeds the power generated by MG2 when it generates maximum power for a predetermined period of time or more.

[0026] If the determination in step S2 is affirmative, the process proceeds to step S3, where the controller 10 performs SOC decline suppression control. If the determination in step S2 is negative, the process proceeds to step S4, where the controller 10 performs normal driving control. First, normal driving control will be described. Normal driving control is driving control performed in normal driving sections (driving sections other than severe driving sections), that is, driving control other than SOC decline suppression control, and includes high charge control. High charge control is charging control of the battery 3 performed in normal driving sections so that the SOC of the battery 3 is maximized when the vehicle V starts driving in the severe driving section.

[0027] FIG. 4 is a flowchart showing an example of normal operation control including high charge control. In this embodiment, "100%" refers to the charge capacity when the battery voltage of the battery 3 reaches the upper limit at which charging and discharging can be safely repeated. As shown in FIG. 4, in step S11, the travel route of the vehicle V is predicted. Specifically, the controller 10 acquires route information to the destination from a navigation system installed in the vehicle V. In step S12, the state of charge of the battery 3 is detected. Specifically, the controller 10 estimates the SOC of the battery 3 from a state detection signal of the battery 3 detected by the SOC sensor 3a.

[0028] In step S13, the acceleration / deceleration of the vehicle V on the travel route is predicted, and the amount of power regenerated (amount of regenerative power) while traveling on the travel route is predicted. Specifically, the acceleration / deceleration of the vehicle V is predicted, and the amount of power regenerated (amount of regenerative power) is predicted based on route information acquired from a navigation system (not shown) and learning results of travel data of the vehicle V in the past.

[0029] In step S14, the controller 10 determines whether the vehicle V is scheduled to travel through a severe driving section. Specifically, the controller 10 determines whether the distance D from the current position of the vehicle V to the severe driving section is equal to or less than a predetermined value D1, based on route information acquired from the navigation system. The predetermined value D1 is set to a distance that will allow the charging rate R of the battery 3 to reach 100% when the vehicle V reaches the entrance to the severe driving section. If it is determined that the distance D from the current position to the severe driving section is equal to or less than the predetermined value D1, the process proceeds to step S15. On the other hand, if it is determined that the distance D is greater than the predetermined value D1, the process proceeds to step S17, where normal control is performed. The normal control is control other than the high charge control performed in the normal driving section, such as charge control according to the SOC. The normal control will be described later.

[0030] In step S15, the target charging rate, which is the charging rate R of the battery 3 that will be the target when the vehicle V starts traveling through the severe driving section (point C1 in FIG. 3), is set to charging rate R1. The charging rate R1 is set to a value obtained by subtracting a fluctuation F of the predetermined charging rate R from 100%. Even while the vehicle V is traveling through the normal driving section, the charging rate R of the battery 3 varies depending on the driving conditions of the vehicle V due to the power consumed and the power regenerated. Therefore, the charging rate R at the time when the vehicle V starts traveling through the severe driving section may differ from the expected value. However, while the vehicle V is traveling through the normal driving section, the fluctuation range of the charging rate R (fluctuation F) falls within an approximately constant range. Therefore, in this embodiment, the target charging rate R1 is set to a value obtained by subtracting a predetermined fluctuation F (fixed value) from 100%. This prevents problems such as overcharging even if there is a discrepancy between the expected values ​​of power consumption W and regenerative power while the vehicle V is traveling through the normal traveling section before reaching the severe traveling section and the actual values ​​of power consumption W and regenerative power. The fluctuation F is set by learning the traveling pattern or based on the results of experiments conducted in advance.

[0031] In step S16, high charge control is performed so that the charging rate R of the battery 3 becomes the charging rate R1 when the vehicle V starts traveling through the severe traveling section. Specifically, the controller 10 drives the engine 1 to generate electricity using the MG2 and controls the regenerative power of the MG4 so that the charging rate R of the battery 3 becomes the charging rate R1 when the vehicle V starts traveling through the severe traveling section.

[0032] By performing high charge control in this manner, the charging rate R of the battery 3 can be made as high as possible when the vehicle V starts traveling through the severe traveling section. This makes it possible to prevent the battery 3 from becoming insufficiently charged while traveling through the severe traveling section.

[0033] When the vehicle reaches the severe driving section, a positive determination is made in step S2 of FIG. 2, and the normal driving control in step S4 is no longer performed. As a result, the processing in the flowchart shown in FIG. 4 is no longer performed. The normal driving control in step S4 may be, for example, charging control according to the SOC. In other words, when performing the SOC decline suppression control in step S3, it is not necessary to perform high charging control before starting driving in the severe driving section. On the other hand, high charging control can increase the charging rate R of the battery 3 as much as possible when starting driving in the severe driving section, so using it in combination with the SOC decline suppression control described next is effective for driving through extremely severe driving conditions.

[0034] Next, the SOC decline suppression control performed in step S3 will be described. The SOC decline suppression control is a control that increases the output P_ICE of the engine 1 when starting to travel in the severe travel section, supplies the generated energy of the MG2 to the MG4 with priority, and supplies the surplus generated energy that is not consumed by the MG4 to the battery 3 as electric energy.

[0035] In severe driving sections, the power consumption W of MG4 normally exceeds the power generation of MG2. Therefore, normally, all of the generated energy supplied to MG4 by the SOC decline suppression control is consumed by MG4, and only the remaining energy is supplied to MG4 as electrical energy from battery 3. As a result, battery power consumption is suppressed, and the decline in SOC is suppressed. On the other hand, in the driving section between points C2 and C3 described with reference to FIG. 3, the power consumption W of MG4 is lower than the power generation of MG2. Therefore, in this case, the surplus generated energy not consumed by MG4 is supplied to battery 3 as electrical energy by the SOC decline suppression control. As a result, the SOC is increased as much as possible even when driving in severe driving sections. "Preferentially" means that the generated energy of MG2 is supplied to MG4 without being supplied to battery 3, but if there is surplus generated energy even after supplying the generated energy to MG4, the surplus generated energy is supplied to battery 3 as electrical energy.

[0036] In the SOC decline suppression control, the output P_ICE is increased regardless of the SOC. In the SOC decline suppression control, the output P_ICE is increased compared to when normal control, which will be described below, is performed, provided that the SOC has not decreased excessively. The condition that the SOC has not decreased excessively means that the normal control does not include the case where the engine 1 is operated at maximum output. The output P_ICE of the engine 1 changes between the SOC decline suppression control and the normal control as follows:

[0037] Fig. 5 is a diagram showing the change in output of engine 1 from the start of driving in a severe driving section. Fig. 6 is a diagram showing the change in output of engine 1 in a comparative example. Fig. 6 shows, as a comparative example, a case where normal control is performed while driving in a severe driving section. Output P_ICEX represents output P_ICE in the comparative example.

[0038] First, referring to Figure 6, in normal control, charging control is performed according to the SOC, and the output P_ICEX increases as the SOC decreases. Multiple thresholds are set for the SOC, and the output P_ICEX is increased in stages each time the SOC falls below one of the thresholds, starting from the highest. When the vehicle starts traveling in a severe driving section near zero elapsed time, the SOC is increased as much as possible through high charging control. Therefore, the output P_ICEX is relatively small at this time, but as the SOC decreases, the output P_ICEX is eventually increased to the maximum output obtainable by engine 1 in a WOT (Wide Open Throttle) state. In this example, vehicle V is traveling in an extremely severe driving situation. Therefore, even if the output P_ICEX is increased to the maximum output, the SOC continues to decrease, and the decrease in SOC is ultimately prevented by the power limit of MG4.

[0039] In the present embodiment shown in FIG. 5, when the severe driving section starts, the engine 1 starts operating in a WOT state due to the SOC decline suppression control, and the output P_ICE is increased to its maximum output. However, the output is not necessarily limited to the maximum output, and it may be increased compared to when normal control is performed, such as to an output range of more than half of the maximum output. The SOC decline suppression control maintains the increased output P_ICE while driving through the severe driving section. As a result, in this embodiment, the decrease in SOC is more gradual than in the comparative example, and the severe driving section can be completed before the power of the MG4 needs to be limited. The reason why the output P_ICE decreases in a noise-like manner in FIG. 5 is as follows.

[0040] Here, the gradient of the road may temporarily become downward even in a severe driving section. In this case, MG4 performs regeneration, making it unnecessary to supply generated energy to MG4. For this reason, in vehicle V, power generation is stopped even while SOC decline suppression control is being executed, and as a result, output P_ICE temporarily becomes zero. As a result, output P_ICE temporarily decreases, and this decrease in output P_ICE appears as a kind of noise in FIG. 5. Therefore, output P_ICE is maintained by SOC decline suppression control at least when MG4 is functioning as an electric motor while traveling in a severe driving section. As a result, power generation is stopped when it is unnecessary to supply generated energy to MG4, thereby preventing more power generation than necessary.

[0041] On the other hand, even when MG4 is functioning as a generator, the output P_ICE may be maintained by SOC decrease suppression control. In this case, all of the generated energy of MG2 becomes surplus and is supplied to battery 3 as electrical energy together with the regenerated energy of MG4. Therefore, in this case, by maintaining output P_ICE within a predetermined SOC setting range so that battery 3 is not overcharged, for example, it is possible to maximize the SOC even when traveling in a severe driving section. Note that on a gentle uphill gradient, the power consumption W of MG4 is lower than the generated power of MG2 when generating maximum power. For this reason, even when power generation is stopped on a downhill gradient, it is possible to supply the surplus generated energy to battery 3 as electrical energy.

[0042] As described above, in the SOC decrease suppression control, for example, the output P_ICE can be set to the maximum output of the engine 1. In this case, the decrease in SOC is suppressed as much as possible, which significantly improves the driving performance in severe driving sections, but it also has the side effect of generating more electricity than necessary when driving in severe driving sections. In light of this, the output P_ICE can also be set, for example, as follows.

[0043] FIG. 7 is a diagram illustrating a first setting method for output P_ICE. The change in SOC represents the change when engine 1 is operated under the same conditions, for example, when engine 1 is not generating electricity. In the first setting method, output P_ICE is set based on the energy consumption rate of MG4 in the severe driving section. The energy consumption rate is the amount of energy consumed by MG4 per unit time, and in FIG. 7 it is represented by the degree of decrease in SOC. In the first setting method, the output P_ICE is set higher as the energy consumption rate increases. Therefore, in the three examples showing different energy consumption rates using the solid line, the dashed-dot line, and the dashed-dot line, the output P_ICE is set highest when the energy consumption rate is the highest, as indicated by the dashed-dot line. This allows output P_ICE to be set taking into account differences in energy consumption depending on the driving load, such as road gradient, thereby enabling driving through the severe driving section with just the right amount of power generation.

[0044] In the first setting method, the energy consumption rate in the severe driving section is predicted before driving in the severe driving section begins, and the output P_ICE is set using SOC decline suppression control based on the predicted energy consumption rate. The energy consumption rate can be predicted based on the predicted value of the power consumption W consumed in the severe driving section and the predicted value of the driving time in the severe driving section. Using the example of Figure 3 described above, the energy consumption rate in this case is predicted by dividing the integrated value of the power consumption W from point C1 to point C4 by the preset driving time. By predicting the energy consumption rate in this way, the output P_ICE to be maintained in the severe driving section can be set taking into account differences in energy consumption depending on the driving load. Note that obtaining information about the severe driving section, such as the preset driving time, is included in predicting the driving time, etc. in the severe driving section.

[0045] FIG. 8 is a diagram illustrating a second setting method for the output P_ICE. In the second setting method, the output P_ICE is set based on the driving distance in the severe driving section. This is because the longer the driving distance, the greater the drop in SOC, as indicated by the thicker arrow. In the second setting method, the longer the driving distance, the higher the output P_ICE is set. Therefore, in three examples showing different driving distances using the solid line, the dashed-dot line, and the dashed-dot line, the output P_ICE is set to the highest for the longest driving distance, the dashed-dot line. This allows the output P_ICE to be set taking into account differences in energy consumption depending on the driving distance, making it possible to drive through the severe driving section with just the right amount of power generation. In addition, the output P_ICE to be maintained in the severe driving section can be set taking into account differences in energy consumption depending on the driving distance.

[0046] In the second setting method, the travel distance of the severe driving section is predicted before starting to drive through the severe driving section, and the output P_ICE is set by the SOC decrease suppression control based on the predicted travel distance. The travel distance can be predicted by obtaining a travel distance set in advance in a navigation system, for example. The second setting method can be used together with the first setting method. This allows differences in driving load and travel distance to be taken into account, making it more effective in driving through the severe driving section with just the right amount of power generation.

[0047] FIG. 9 is a diagram illustrating the effect depending on the driving time in a severe driving situation. Comparative Example 1 shows a case where high charging control and SOC decline suppression control are not performed. Comparative Example 2 shows a case where high charging control is performed but SOC decline suppression control is not performed. In Comparative Example 2, the SOC at the start of driving in a severe driving section is increased as much as possible by high charging control. Therefore, Comparative Example 2 can ensure a longer driving time in a severe driving situation compared to Comparative Example 1. In this embodiment, not only high charging control but also SOC decline suppression control is performed. Therefore, according to this embodiment, a longer driving time in a severe driving situation can be ensured compared to not only Comparative Example 1 but also Comparative Example 2.

[0048] FIG. 10 is a diagram illustrating the effect of the cooling request for battery 3. In Comparative Example 1, high charge control is not performed, but SOC decline suppression control is not performed either, so all of the power consumed by driving MG4 while traveling in the severe driving section is supplied by power from battery 3. As a result, a large amount of power is taken from battery 3, making battery 3 more likely to overheat and increasing the cooling request for battery 3. In the present embodiment, high charge control is performed, but during the subsequent severe driving section, SOC decline suppression control causes the generated power of MG2 to be supplied to MG4. As a result, a small amount of power is taken from battery 3, making battery 3 less likely to overheat and reducing the cooling request for battery 3.

[0049] Next, the main effects of this embodiment will be described.

[0050] The energy control method for a vehicle V according to this embodiment is used in a vehicle V that has an engine 1, an MG2 driven by the engine 1 to generate electricity, a battery 3 charged by the MG2, and an MG4 that drives drive wheels 6 with power supplied from the battery 3 or power generated by the MG2. This method includes increasing the output power P_ICE of the engine 1 when the vehicle V starts traveling in a severe driving section that includes a section in which the MG2 continues to consume more power than it can generate, preferentially supplying the generated energy of the MG2 to the MG4 while traveling in the severe driving section, and supplying surplus generated energy not consumed by the MG4 while traveling in the severe driving section to the battery 3 as electric energy.

[0051] According to this method, the output power P_ICE of the engine 1 is increased when starting to travel through the severe driving section, and the generated energy is preferentially supplied to the MG4 while traveling through the severe driving section, thereby suppressing power consumption of the battery 3 even while traveling through the severe driving section. Furthermore, surplus generated energy is supplied to the battery 3 as electric energy, so the SOC can be increased as much as possible even while traveling through the severe driving section. As a result, excessive decreases in the SOC are suppressed, and it becomes less necessary to limit the power of the MG4 or charge the battery 3 while the vehicle is stopped, thereby improving the vehicle's ability to traverse severe driving conditions.

[0052] The energy control method for the vehicle V according to this embodiment may further include predicting the energy consumption rate of the MG4 in the severe driving section before starting to drive through the severe driving section. In this case, the output power P_ICE of the engine 1 can be set based on the predicted energy consumption rate. According to this method, the output power P_ICE can be set taking into account differences in energy consumption depending on the driving load, such as road gradient, so that the vehicle can travel through the severe driving section with just the right amount of power generation. Furthermore, the output power P_ICE to be maintained in the severe driving section can be set taking into account differences in energy consumption depending on the driving load.

[0053] The energy control method for the vehicle V according to this embodiment may further include predicting a travel distance in the severe travel section before starting travel in the severe travel section. In this case, the output power P_ICE of the engine 1 can be set based on the predicted travel distance. According to this method, the output power P_ICE can be set taking into account differences in energy consumption depending on travel distance, so that travel in the severe travel section can be achieved with just the right amount of power generation. Furthermore, the output power P_ICE to be maintained in the severe travel section can be set taking into account differences in energy consumption depending on travel distance.

[0054] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments. [Explanation of symbols]

[0055] 1 engine 2 MG (first motor) 3 Battery 4 MG (second motor) 5 inverters 6 drive wheels 10 Controllers V vehicle

Claims

1. 1. An energy control method for a vehicle having an engine, a first motor driven by the engine to generate electricity, a battery charged by the first motor, and a second motor that drives drive wheels using electric power supplied from the battery or electric power generated by the first motor, comprising: increasing the output of the engine when starting to travel in a severe travel section including a section in which the first motor continues to travel at an amount of power consumption that exceeds the amount of power that can be generated; During travel in the severe travel section, the generated energy of the first motor is preferentially supplied to the second motor; and supplying the surplus generated energy that is not consumed by the second motor while traveling in the severe traveling section to the battery as electric energy, and further comprising predicting an energy consumption rate of the second motor in the severe driving section before starting driving in the severe driving section. The output of the engine is set higher as the predicted energy consumption rate increases. A vehicle energy control method comprising:

2. An energy control method for a vehicle having an engine, a first motor driven by the engine to generate electricity, a battery charged by the first motor, and a second motor that drives drive wheels with power supplied from the battery or power generated by the first motor, comprising: increasing the output of the engine when starting to travel in a severe travel section including a section in which the first motor continues to travel at an amount of power consumption that exceeds the amount of power that can be generated; During travel in the severe travel section, the generated energy of the first motor is preferentially supplied to the second motor; and and further comprising predicting a travel distance in the severe travel section before starting travel in the severe travel section. The output of the engine is set higher as the predicted traveling distance is longer. A vehicle energy control method comprising:

3. An energy control device for a vehicle having an engine, a first motor driven by the engine to generate electricity, a battery charged by the first motor, and a second motor that drives drive wheels with power supplied from the battery or power generated by the first motor, a controller that performs SOC decrease suppression control by increasing the output of the engine when starting to travel in a severe driving section including a section in which the first motor continues to travel at an amount of power consumption that exceeds the amount of power that can be generated, and by preferentially supplying the generated energy of the first motor to the second motor while traveling in the severe driving section, and supplying the surplus generated energy that is not consumed by the second motor to the battery as electric energy; The controller predicting an energy consumption rate of the second motor in the severe travel section before starting travel in the severe travel section; An energy control device for a vehicle, characterized in that the output of the engine is set higher as the predicted energy consumption rate increases.

4. An energy control device for a vehicle having an engine, a first motor driven by the engine to generate electricity, a battery charged by the first motor, and a second motor that drives drive wheels with power supplied from the battery or power generated by the first motor, a controller that performs SOC decrease suppression control by increasing the output of the engine when starting to travel in a severe driving section including a section in which the first motor continues to travel at an amount of power consumption that exceeds the amount of power that can be generated, and by preferentially supplying the generated energy of the first motor to the second motor while traveling in the severe driving section, and supplying the surplus generated energy that is not consumed by the second motor to the battery as electric energy; The controller predicting a travel distance in the severe travel section before starting travel in the severe travel section; The output of the engine is set higher as the predicted traveling distance is longer.

1. A vehicle energy control device comprising:

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