Control device for hybrid vehicle

Abstract

To provide a technique capable of improving the estimation accuracy of an execution possible period in a control device for a hybrid vehicle.SOLUTION: A control device for a hybrid vehicle includes: a setting unit which sets engine torque and motor generator torque according to request torque; and an information collection unit which collects travel information. The setting unit sets a difference between the engine torque and the request torque as motor generator torque as an assist mode when the allowable upper limit of the engine torque is smaller than the request torque, sets the sum of charging torque and the request torque as the engine torque as a charging travel mode when transitioning from a state where the allowable upper limit of engine torque is smaller than the request torque to a state where it is greater than the request torque, and refers to a map in which travel information during the assist mode is associated with an execution possible period where execution of the charging travel mode is possible to estimate the execution possible period.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control device for a hybrid vehicle. [Background technology]

[0002] Conventionally, hybrid vehicles are known that are equipped with an engine and a motor generator as driving sources, and a secondary battery that exchanges electric power with the motor generator. In such hybrid vehicles, the distribution of engine torque and motor generator torque is set according to the torque required for acceleration. Patent documents 1 to 3 disclose various control methods for setting this distribution. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-77897 A [Patent Document 2] JP 2002-256918 A [Patent Document 3] JP 2011-63089 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Documents 1 to 3, sufficient consideration was not given to suppressing a shortage of the charge amount of the secondary battery consumed by the operation of the motor generator. Here, in order to suppress a shortage of the charge amount of the secondary battery, for example, when the allowable upper limit of the engine torque at which the output is allowed is greater than the required torque, it is conceivable to implement a charging travel mode in which the sum of the charging torque used to charge the secondary battery and the required torque is set as the engine torque. In this case, the charging torque should be set according to the length of the executable period in which the charging travel mode can be implemented. However, this executable period is difficult to estimate because it varies due to the driving environment and the driver's state (hurrying, familiar road, etc.). In addition, if the charging torque is set according to the executable period estimated with low accuracy, there is a concern that the secondary battery cannot be sufficiently charged, and the effect of improving fuel efficiency and reducing exhaust gas due to the driving assistance of the motor generator cannot be maintained. Therefore, when the charging travel mode is implemented, a technology that can improve the estimation accuracy of the executable period is desired.

[0005] The present invention has been made to solve at least part of the above-mentioned problems, and aims to provide a technology that can improve the estimation accuracy of the executable period in a control device for a hybrid vehicle. [Means for solving the problem]

[0006] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following forms.

[0007] (1) According to one aspect of the present invention, a control device for a hybrid vehicle is provided. This control device is a control device for a hybrid vehicle including an engine and a motor generator as driving sources, and a secondary battery that supplies power to the motor generator and stores the power generated by the motor generator, and includes a setting unit that sets an engine torque output from the engine and a motor generator torque output from the motor generator in accordance with a required torque requested of the hybrid vehicle, and an information collecting unit that collects driving information about the hybrid vehicle while it is traveling. When an allowable upper limit of the engine torque for which output is allowed is smaller than the required torque, the setting unit sets the engine torque equal to or less than the allowable upper limit as an assist mode, and sets the difference between the engine torque and the required torque as the motor generator torque. When the allowable upper limit of the engine torque transitions from a state in which it is smaller than the required torque to a state in which it is larger than the required torque, the setting unit sets the engine torque to be equal to or less than the allowable upper limit as a charge driving mode, and sets the motor generator torque to a negative value in accordance with the charge torque, and estimates the feasible period by referring to a map that corresponds the driving information in the assist mode to a period in which the charge driving mode can be implemented.

[0008] The inventors of the present application analyzed a number of data obtained when a hybrid vehicle was driven in urban areas, suburban areas, and on highways, and found that there is a positive correlation between the driving information in the assist mode immediately before the charging driving mode is started and the executable period during which the charging driving mode can be implemented. According to this configuration, the executable period is estimated by referring to a map that is created based on such knowledge and that associates the driving information in the assist mode with the executable period, and therefore the estimation accuracy of the executable period can be improved. As a result, the charging driving mode is implemented based on the accurately estimated executable period, and therefore it is possible to prevent the secondary battery from becoming insufficient, thereby maintaining the effect of improving fuel efficiency and reducing exhaust gases due to the driving assistance of the motor generator.

[0009] (2) In the control device of the above embodiment, the driving information collected by the information collecting unit may include the vehicle speed of the hybrid vehicle at the time when the assist mode ends, and the driving information associated with the executable period may include the vehicle speed of the hybrid vehicle at the time when the assist mode ends. The inventors of the present application have found that there is a positive correlation between the vehicle speed of the hybrid vehicle at the time when the assist mode ends and the executable period. With this configuration, since the vehicle speed is included in the driving information associated with the executable period in the map, it is possible to further improve the estimation accuracy of the executable period.

[0010] (3) In the control device of the above embodiment, the map may be updated using the driving information in the assist mode and the executable period corresponding to the driving information when the hybrid vehicle is driven for the first time. According to this configuration, the map can be updated using data obtained when the hybrid vehicle is first driven, so that the accuracy of estimating the executable period can be further improved.

[0011] (4) In the control device of the above embodiment, a communication unit may be further provided for communicating with an external device of the hybrid vehicle, and the setting unit may be capable of referring to the map updated using the driving information during the assist mode when another hybrid vehicle is traveling and the executable period corresponding to the driving information via communication with the external device. According to this configuration, since it is possible to refer to a map that has been updated using data obtained by traveling other hybrid vehicles, it is possible to further improve the accuracy of estimating the executable period.

[0012] (5) In the control device of the above embodiment, a communication unit that communicates with an outside of the hybrid vehicle may be further provided, and the setting unit may be capable of referring to the map corrected using an other vehicle map that is referenced by another of the hybrid vehicles via communication with the outside. According to this configuration, since it is possible to refer to a map corrected using the other vehicle map that is being referred to by the other hybrid vehicle, it is possible to further improve the accuracy of estimating the executable period.

[0013] (6) In the control device according to the above aspect, the setting unit may set the charging torque in accordance with the estimated possible charging period. According to this configuration, when the estimated executable period is relatively long, the charging torque is set to be small, so that the secondary battery can be charged while suppressing an increase in engine torque. On the other hand, when the estimated executable period is relatively short, the charging torque is set to be large, so that the charge amount of the secondary battery can be ensured even if the estimated executable period is short. In other words, according to this configuration, an appropriate charging torque can be set in terms of the load on the engine and the charging efficiency in the charging travel mode.

[0014] The present invention can be realized in various forms, for example, in the form of a hybrid vehicle equipped with the control device, a control method for a hybrid vehicle, and the like. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is an explanatory diagram illustrating the configuration of a control device according to the first embodiment. [Diagram 2] 4 is an explanatory diagram of a mode that changes depending on the vehicle speed of a hybrid vehicle. FIG. [Diagram 3] FIG. 11 is an explanatory diagram relating to setting of the duration of the charging travel mode. [Figure 4] FIG. 11 is an explanatory diagram relating to setting of the duration of the charging travel mode. [Diagram 5] FIG. 11 is an explanatory diagram relating to setting of the duration of the charging travel mode. [Figure 6] FIG. 11 is an explanatory diagram showing the occurrence frequency of vehicle speeds extracted from market driving patterns. [Figure 7] FIG. 11 is an explanatory diagram showing the relationship between the vehicle speed at the time when the assist mode ends and the executable period. [Figure 8] FIG. 11 is an explanatory diagram showing a map in which vehicle speed is associated with an executable period; [Figure 9] 11A and 11B are explanatory diagrams showing the driving results of a hybrid vehicle with different duration setting periods. [Figure 10] 5 is an explanatory diagram showing the results of a comparison of performance between a hybrid vehicle of a comparative example and a hybrid vehicle equipped with the control device of the present embodiment. FIG. [Figure 11] FIG. 11 is an explanatory diagram illustrating the configuration of a control device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] First Embodiment 1 is an explanatory diagram illustrating the configuration of a hybrid vehicle 1 equipped with a control device 20 (described in detail later) according to a first embodiment. In addition to the control device 20, the hybrid vehicle 1 is equipped with an engine 11, a transmission 12, a propeller shaft 13, a differential gear 14, a drive shaft 15, tires 16, a motor generator 17, and a secondary battery 18.

[0017] In the hybrid vehicle 1, engine torque (hereinafter referred to as EG torque) output from the engine 11 is transmitted to the propeller shaft 13 as axle torque. During power running, motor generator torque (hereinafter referred to as MG torque) output from the motor generator 17 using electric power supplied from a secondary battery 18 is transmitted to the propeller shaft 13 as axle torque. The axle torque is transmitted to the tires 16 as drive torque via the differential gear 14 and the drive shaft 15. The engine 11 and the motor generator 17 serve as drive sources for the hybrid vehicle 1.

[0018] On the other hand, during regeneration, the axle torque is transmitted to the motor generator 17 as MG torque. This MG torque is used for power generation by the motor generator 17. The electric power generated by the motor generator 17 is charged to the secondary battery 18. In this way, the secondary battery 18 supplies electric power to the motor generator 17 during power running, and stores the electric power generated by the motor generator 17 during regeneration.

[0019] The control device 20 includes a setting unit 21, an EG drive control unit 23, an MG drive control unit 25, and an information collection unit 27. The setting unit 21 sets the EG torque output from the engine 11 and the MG torque output from the motor generator 17 according to the required torque required for the hybrid vehicle 1. Here, the required torque is calculated according to the depression amount of an accelerator pedal (not shown) and a brake pedal (not shown) of the hybrid vehicle 1. The EG drive control unit 23 drives the engine 11 according to the set EG torque. The MG drive control unit 25 drives the motor generator 17 according to the set MG torque. The information collection unit 27 collects travel information related to the hybrid vehicle 1 during travel. The information collection unit 27 periodically collects the travel information while the hybrid vehicle 1 is operating, and transmits a signal indicating the information to the setting unit 21. For example, the travel information includes the current charge amount of the secondary battery 18.

[0020] FIG. 2 is an explanatory diagram of a mode that changes according to the vehicle speed of the hybrid vehicle 1. FIG. 2(A) is a diagram showing the change over time of the vehicle speed of the hybrid vehicle 1. The vertical axis of FIG. 2(A) indicates the vehicle speed of the hybrid vehicle 1, and the horizontal axis of FIG. 2(A) indicates time. The horizontal axes of FIG. 2(B) and (C) described below also indicate time. FIG. 2(B) is a diagram showing the change over time of the EG torque output by the engine 11. The vertical axis of FIG. 2(B) indicates the EG torque output by the engine 11. The solid line b1 of FIG. 2(B) indicates the EG torque that changes over time, and the dashed line b2 indicates the required torque that changes over time. FIG. 2(C) is a diagram showing the change over time of the charge amount of the secondary battery 18. The vertical axis of FIG. 2(C) indicates the charge amount of the secondary battery 18. The solid line c1 of FIG. 2(C) indicates the charge amount of the secondary battery 18 that changes over time. The dashed line c2 in FIG. 2C indicates a recovery target charge amount that is a recovery target for the charge amount of the secondary battery 18.

[0021] At time t1, when an acceleration request to accelerate to vehicle speed V (see FIG. 2(A)) is detected due to an increase in accelerator pedal depression, a required torque is calculated according to the depression amount. At this time, the information collecting unit 27 transmits a signal indicating information such as the intake air amount, intake pipe pressure, fuel injection amount, and rotation speed of the engine 11 as driving information to the setting unit 21. Based on this information, the setting unit 21 sets the EG torque below the upper limit of the allowable range (allowable upper limit) that satisfies the emission standards for exhaust gas from the engine 11. With this setting, the EG torque starts to increase from time t1, as shown by the solid line b1 in FIG. 2(B).

[0022] The allowable range that satisfies the emission standards of the exhaust gas from the engine 11 means an allowable range that satisfies the emission standards for harmful substances such as nitrogen oxides (NOx), particulate matter (PM), hydrocarbons (HC), and carbon monoxide (CO) in the exhaust gas emitted from the hybrid vehicle 1. This allowable range is calculated using an engine model expressed by a physical formula created by a physical model, an empirical formula, or a combination of these, a numerical map, a neural network, or the like. The allowable range at the next point in time is calculated by inputting the current operating conditions (rotation speed, load, etc.) and state quantities (boost pressure, EGR rate, etc.) into such an engine model. Note that the method of setting such an allowable range is not limited to a method using an engine model, and any method may be used.

[0023] The EG torque between timing t1 and timing t3 is the upper limit of the allowable EG torque. Therefore, during this period, the upper limit of the allowable EG torque that is allowed to be output is smaller than the required torque. In this case, the setting unit 21 sets an EG torque equal to or lower than the upper limit of the allowable EG torque as the assist mode, and sets the difference between this EG torque and the required torque as the MG torque. That is, during the period from timing t1 to timing t3, the MG torque is set as an auxiliary torque for the EG torque that is set to be equal to or lower than the upper limit of the allowable EG torque. At this time, as shown by the solid line c1 in FIG. 2C, during the period from timing t1 to timing t3, the charge amount of the secondary battery 18 decreases by the amount of the MG torque used to assist the EG torque.

[0024] As the vehicle speed of the hybrid vehicle 1 approaches the vehicle speed V (see FIG. 2(A)), the accelerator pedal depression amount starts to decrease from timing t2, and the required torque also starts to decrease (see FIG. 2(B)). After that, at timing t3, the decreasing required torque becomes equal to the EG torque that increases while maintaining the allowable upper limit (solid line b1 and dashed line b2 intersect). At this time, the allowable upper limit of the EG torque transitions from a state in which it is smaller than the required torque to a state in which it is larger than the required torque, and this triggers the setting unit 21 to set the sum of the charging torque used to charge the secondary battery 18 and the required torque as the EG torque for the charging travel mode. FIG. 2(B) shows the charging torque Tc. The setting unit 21 also sets a negative MG torque according to the charging torque. The negative MG torque means the MG torque during regeneration in which power is generated to be stored in the secondary battery 18. The charging torque is calculated by dividing the power deficit, which is the difference between the target recovery charge amount (see dashed line c2 in FIG. 2C), which is the recovery target for the charge amount of the secondary battery 18, and the current charge amount of the secondary battery 18 (see solid line c1 in FIG. 2C), by the duration of the charging travel mode and the rotation speed of the motor generator 17. The target recovery charge amount is set in consideration of the amount of power that can be recovered by brake regeneration when the hybrid vehicle 1 comes to a stop from the current vehicle speed, the charging efficiency of the secondary battery 18 by the motor generator 17, etc. In addition, if the sum of the calculated charging torque and the required torque is greater than the allowable upper limit of the EG torque, it is preferable to adjust the charging torque so that the sum is equal to or less than the allowable upper limit of the EG torque. The calculation of the charging torque will be described later.

[0025] Since the charging travel mode is continued after the timing t3, the charge amount of the secondary battery 18 reaches the recovery target charge amount at the timing t4 as shown in FIG. 2C (the solid line c1 and the dashed line c2 intersect). At this time, the charging travel mode ends, and as shown by the solid line b1 in FIG. 2B, the EG torque corresponding to only the required torque is set by setting the torque corresponding to the charging torque Tc out of the EG torque corresponding to the sum of the charging torque and the required torque to 0. Since the EG torque corresponding to only the required torque is set between the timing t4 and the timing t5, the solid line b1 and the dashed line b2 overlap. Then, at the timing t5, the depression amount of the accelerator pedal increases again, and when the required torque is calculated according to the depression amount, the setting unit 21 sets the EG torque equal to or less than the allowable upper limit as the assist mode, and sets the difference between the EG torque and the required torque as the MG torque. In FIG. 2, the charging travel mode ends when the charge amount of the secondary battery 18 reaches the recovery target charge amount. However, the charging travel mode also ends when the allowable upper limit of the EG torque becomes smaller than the required torque again, or when the required torque becomes negative due to an increase in the amount of depression of the brake pedal of the hybrid vehicle 1.

[0026] In the charging travel mode (from timing t3 to timing t4 in FIG. 2), the charging torque used to set the EG torque and the MG torque is calculated by dividing the amount of power shortage by the duration of the charging travel mode and the rotation speed of the motor generator 17, as described above. The amount of power shortage and the rotation speed of the motor generator 17 change from moment to moment, but can be acquired from the travel information successively collected by the information collecting unit 27. On the other hand, although the end timing of the duration of the charging travel mode is unknown at the start of the charging travel mode, it is a parameter required for calculating the charging torque used to set the EG torque and the MG torque in the charging travel mode, so it needs to be set in advance at the start of the charging travel mode. From the viewpoint of the load on the engine 11 and the charging efficiency in the charging travel mode, the longer the duration is set, the smaller the charging torque is calculated, and the shorter the duration is set, the larger the charging torque is calculated.

[0027] 3 to 5 are explanatory diagrams relating to setting of the duration of the charging travel mode. The vertical and horizontal axes in Figs. 3 to 5 are the same as those in Fig. 2(B). Also, the dashed dotted line b2 indicates the required torque that changes over time, as in Fig. 2.

[0028] In Fig. 3, timing st is the timing when the allowable upper limit of the EG torque changes from a state where it is smaller than the required torque to a state where it is larger than the required torque, and corresponds to the timing when the mode changes from the assist mode to the charging driving mode. Timing gen is the timing when the allowable upper limit of the EG torque becomes smaller than the required torque due to an increase in the amount of depression of the accelerator pedal, and corresponds to the timing when the mode changes from the charging driving mode to the assist mode. In other words, the period from timing st to timing gen is an executable period g during which the charging driving mode can be implemented. The same applies to timing st, timing gen, and executable period g in Figs. 4 and 5.

[0029] On the other hand, in FIG. 3, the duration setting period f is a period that is set in advance as an expected length of the period during which the charge traveling mode will continue in order to calculate the charging torque at the start of the charge traveling mode. Timing fen is the end timing of the duration setting period f. The same applies to the duration setting period f and timing fen in FIGS. 4 and 5. In FIGS. 3 to 5, when the duration setting period f is set, the charge traveling mode ends at timing fen. Also, even if the executable period g ends during the duration setting period f, the charge traveling mode ends. In FIGS. 3 to 5, the magnitude relationship between the duration setting period f and the executable period g is different. FIG. 3 shows a case where the duration setting period f is longer than the executable period g. FIG. 4 shows a case where the duration setting period f is shorter than the executable period g. FIG. 5 shows a case where the duration setting period f and the executable period g match.

[0030] First, FIG. 3 will be described. The solid line d1 in FIG. 3 indicates the EG torque that changes over time. In the case of FIG. 3, the executable period g ends (timing gen arrives) before the timing fen arrives, so the charge travel mode can only continue for a period shorter than the duration setting period f. The charge torque Tc1 in the charge travel mode at this time is calculated on the assumption that the charge travel mode continues for the duration setting period f. In FIG. 3, the duration setting period f is interrupted by the end of the executable period g, so the amount of power generated in the charge travel mode implemented during this period (from timing st to timing gen) is less than the amount of power generated if the charge travel mode is implemented throughout the duration setting period f. If the occurrence frequency of the event as shown in FIG. 3 is high, the amount of charge in the secondary battery 18 becomes insufficient, and as a result, the EG torque cannot be assisted by the MG torque in the assist mode. As a result, for example, an EG torque greater than the allowable upper limit may be output in order to meet the required torque, making it impossible to meet exhaust gas emission standards from the engine 11, or the MG torque may be insufficient to assist the EG torque below the allowable upper limit, so that only a portion of the required torque can be met, thereby impairing the drivability of the hybrid vehicle 1.

[0031] Next, FIG. 4 will be described. The solid line d2 in FIG. 4 indicates the EG torque that changes over time, similar to the solid line d1 in FIG. 3. In the case of FIG. 4, the duration setting period f ends before the end of the executable period g. For this reason, a sufficient amount of power can be secured, but the shorter the duration setting period f is set, the larger the calculated charging torque (shown as charging torque Tc2 in FIG. 4) is. In some cases, the EG torque in the charging travel mode may be greater than the required torque when acceleration is required. In other words, the sum of the charging torque and the required torque in the charging travel mode may be greater than the allowable upper limit of the EG torque, which is undesirable because it would not be possible to meet the emission standards for exhaust gas from the engine 11.

[0032] Finally, FIG. 5 will be described. The solid line d3 in FIG. 5 indicates the EG torque that changes over time, similar to the solid line d1 in FIG. 3 and the solid line d2 in FIG. 4. In the case of FIG. 5, the executable period g ends at the same time as the continuous setting period f. That is, the timing gen and the timing fen are the same timing. Therefore, since the continuous setting period f and the executable period g match, it is possible to ensure a sufficient amount of power generation while suppressing the calculation of a large charging torque (shown as charging torque Tc3 in FIG. 5) due to the short continuous setting period f. From the explanation of FIG. 3 to FIG. 5, when setting the continuous setting period f in advance, it is preferable to set it so that it matches the executable period g. However, the executable period g is difficult to estimate because it varies due to the influence of the driving environment and the driver's state (hurrying, familiar road, etc.).

[0033] In this regard, the inventors of the present application analyzed a plurality of data obtained when the hybrid vehicle 1 was driven in urban areas, suburban areas, and on expressways, and found that there is a positive correlation between the driving information in the assist mode immediately before the charging driving mode is started and the executable period g. Therefore, the setting unit 21 included in the control device 20 of this embodiment estimates the executable period g by referring to a map in which the driving information in the assist mode and the executable period g are associated with each other. Here, estimating the executable period g from the map means applying the driving information in the assist mode to this map and acquiring the executable period g corresponding to the driving information. In this embodiment, the driving information associated with the executable period g is the vehicle speed of the hybrid vehicle 1 at the time when the assist mode ends. Therefore, the driving information collected by the information collecting unit 27 includes the vehicle speed of the hybrid vehicle 1 at the time when the assist mode ends. In addition, the setting unit 21 sets the charging torque (corresponding to the charging torques Tc1 to Tc3 in FIGS. 3 to 5) according to the estimated executable period g.

[0034] The reason for referring to the map in which the driving information in the assist mode and the executable period g are associated when estimating the executable period g will be described with reference to Figs. 6 to 8. Fig. 6 is an explanatory diagram showing the frequency of occurrence of the vehicle speed extracted from the market driving pattern of the hybrid vehicle 1. The horizontal axis of Figs. 6(A) to (C) all indicates the vehicle speed of the hybrid vehicle 1, and the vertical axis of Figs. 6(A) to (C) all indicates the frequency of occurrence of the vehicle speed of the hybrid vehicle 1. Fig. 6(A) shows the frequency of occurrence of the vehicle speed when the hybrid vehicle 1 runs in an urban area. Fig. 6(B) shows the frequency of occurrence of the vehicle speed when the hybrid vehicle 1 runs in a suburban area. Fig. 6(C) shows the frequency of occurrence of the vehicle speed when the hybrid vehicle 1 runs on a highway. As Figs. 6(A) to (C) show, the frequency of occurrence of the vehicle speed of the hybrid vehicle 1 differs between an urban area, a suburban area, and a highway.

[0035] FIG. 7 is an explanatory diagram showing the relationship between the vehicle speed Vc of the hybrid vehicle 1 at the time when the assist mode ends (corresponding to timing st in FIGS. 3 to 5) and the executable period g. The horizontal axis of FIG. 7 indicates the vehicle speed Vc, and the vertical axis of FIG. 7 indicates the executable period g. The multiple white circle plots in FIG. 7 indicate the measurement results measured when measuring the market driving patterns of FIGS. 6(A) to (C). The multiple black circle plots in FIG. 7 indicate the average value of the vehicle speed Vc and the average value of the executable period g in each vehicle speed range. The vehicle speed ranges are a vehicle speed range of 0 to 30 km / h, a vehicle speed range of 30 to 60 km / h, a vehicle speed range of 60 to 90 km / h, a vehicle speed range of 90 to 120 km / h, and a vehicle speed range of 120 to 150 km / h.

[0036] FIG. 8 is an explanatory diagram showing a map M in which the vehicle speed Vc corresponds to the executable period g. The map M shown by an approximation curve is derived by fitting a quadratic curve to the multiple black circle plots shown in FIG. 7 using the least squares method. As shown in FIG. 8, it was confirmed that there is a positive correlation between the driving information in the assist mode immediately before the charging driving mode is started (in this embodiment, the vehicle speed Vc of the hybrid vehicle 1 at the time when the assist mode is ended) and the executable period g. For this reason, as described above, the setting unit 21 included in the control device 20 of this embodiment estimates the executable period g by referring to the map M in which the driving information in the assist mode corresponds to the executable period g. This map M may be stored in the setting unit 21, or may be stored in a separate device that can communicate with the setting unit 21. This separate device may be provided either inside or outside the hybrid vehicle 1.

[0037] Fig. 9 is an explanatory diagram showing the driving results of each hybrid vehicle (details will be described later) with different lengths of the preset sustained setting period f. The driving results shown in Fig. 9 are the results when each hybrid vehicle runs in an urban area from 0 to 2000 seconds, runs in a suburban area from 2000 to 4000 seconds, and runs on a highway from 4000 to 6000 seconds.

[0038] The solid line M1 is the result of driving the hybrid vehicle 1 equipped with the control device 20 of this embodiment. In the hybrid vehicle 1, the length of the possible period g estimated by referring to the map M is set as the sustained setting period f every time the assist mode is switched to the charging driving mode (corresponding to the timing st in Figs. 3 to 5). The sustained setting period f set by the control device 20 of this embodiment is used to calculate the charging torque at the start of the charging driving mode, and the charging driving mode is terminated when the end timing of the sustained setting period f (corresponding to the timing fen in Figs. 3 to 5) arrives. As described in Fig. 2, the charging driving mode of the hybrid vehicle 1 is also terminated in any of the following cases: when the charge amount of the secondary battery 18 reaches the recovery target charge amount, when the allowable upper limit of the EG torque becomes smaller than the required torque again, or when the required torque becomes negative due to an increase in the amount of depression of the brake pedal of the hybrid vehicle 1. The dashed line M2 is the result of driving the hybrid vehicle as a comparative example in which the sustained setting period f is always set to 10 seconds. The dashed-dotted line M3 shows the driving results of a hybrid vehicle in which the sustained setting period f is always set to 15 seconds as a comparative example. The dashed-two-dotted line M4 shows the driving results of a hybrid vehicle in which the sustained setting period f is always set to 20 seconds as a comparative example. In these comparative examples, as with the hybrid vehicle 1, the sustained setting period f is used to calculate the charging torque at the start of the charging travel mode, and when the end timing of the sustained setting period f (corresponding to timing fen in Figures 3 to 5) arrives, the charging travel mode is ended.

[0039] The horizontal axis in FIG. 9 indicates the running time, and the vertical axis in FIG. 9 indicates the accumulated value of the error. The error is the difference between a preset duration setting period f and the actual duration during which the charging running mode continues. If the duration setting period f is longer than the actual duration, the accumulated value is increased by the amount of the error, and if the duration setting period f is shorter than the actual duration, the accumulated value is decreased by the amount of the error. For example, if the duration setting period f is 2 seconds longer than the actual duration, the accumulated value is increased by 2 seconds, and if the duration setting period f is 2 seconds shorter than the actual duration, the accumulated value is decreased by 2 seconds.

[0040] Among the driving results of the hybrid vehicle with a constant sustained setting period f (dashed line M2, dashed line M3, and double-dashed line M4), in the hybrid vehicle in which the sustained setting period f is always set to 15 seconds, as shown by dashed line M3, the cumulative value of the error was almost zero. On the other hand, in the hybrid vehicle 1 in which the sustained setting period f is set to the feasible period g estimated by referring to map M each time the charging driving mode is started, as shown by solid line M1, the cumulative value of the error was also almost zero. From these results, it was confirmed that when the sustained setting period f is set by referring to map M, it is possible to drive with the cumulative value of the error being almost zero without performing a parameter study on the sustained setting period f.

[0041] FIG. 10 is an explanatory diagram showing the results of comparing the performance of a hybrid vehicle that always sets the sustained setting period f to 15 seconds and a hybrid vehicle 1 equipped with the control device 20 of this embodiment. The results shown in FIG. 10 are the results when the vehicle is driven in an urban area from 0 to 2000 seconds, in the suburbs from 2000 to 4000 seconds, and on a highway from 4000 to 6000 seconds, as in FIG. 9. FIG. 10 shows the ratio of the performance of the hybrid vehicle 1 equipped with the control device 20 of this embodiment when the performance of the hybrid vehicle that always sets the sustained setting period f to 15 seconds is set to 1. The types of performance compared are the charge amount, fuel efficiency, and NOx. x The amount of NO emissions is shown. The larger the ratio, the more improved the charge amount and fuel efficiency are. x The smaller the ratio, the greater the improvement in emissions is considered to be.

[0042] From the results shown in FIG. 10, the hybrid vehicle 1 equipped with the control device 20 of this embodiment had the same fuel economy as the hybrid vehicle in which the continuous setting period f is always set to 15 seconds, but the charge amount and NO xIt was confirmed that the amount of emissions was improved. Meanwhile, in the results this time, only the charge amount was improved among the charge amount and fuel efficiency, which are the performance related to the driving energy of the hybrid vehicle, but it is also possible to reduce the amount of improvement in the charge amount (the portion corresponding to the ratio 0.05=1.05-1 in FIG. 10) by decreasing the value of the recovery target charge amount of the secondary battery 18, and to use the reduced amount for improving fuel efficiency.

[0043] Furthermore, map M (see FIG. 8) is updated using the driving information in the assist mode when the hybrid vehicle 1 is newly driven and the executable period g corresponding to the driving information. In this embodiment, map M is updated using the vehicle speed of the hybrid vehicle 1 at the time when the assist mode ends and the executable period g corresponding to the vehicle speed when the hybrid vehicle 1 is newly driven. The vehicle speed and the executable period g corresponding to it correspond to the white circle plots shown in FIG. 7. When updating, weights are applied to each of the data newly obtained in the new drive (new white circle plots) and the black circle plots (see FIGS. 7 and 8). Each weight is set taking into consideration the degree of reflection of the new white circle plots relative to the black circle plots.

[0044] As described in FIG. 6 to FIG. 8, the inventors of the present application analyzed a plurality of data obtained when the hybrid vehicle 1 was driven in urban areas, suburban areas, and on expressways, and found that there is a positive correlation between the driving information in the assist mode immediately before the charging driving mode is started (in this embodiment, the vehicle speed Vc of the hybrid vehicle 1 at the time when the assist mode is ended) and the executable period g. According to the control device 20 of the first embodiment described above, the executable period g is estimated by referring to the map M that associates the driving information in the assist mode with the executable period g, which is created based on such knowledge, and therefore the estimation accuracy of the executable period g can be improved. As a result, the charging driving mode is implemented (an appropriate charging torque is set) based on the accurately estimated executable period g, and therefore it is possible to prevent the charge amount of the secondary battery 18 from becoming insufficient, and therefore it is possible to maintain the effect of improving fuel efficiency and reducing exhaust gas by the driving assistance of the motor generator 17.

[0045] In the control device 20 of the first embodiment, the travel information associated with the executable period g is the vehicle speed Vc of the hybrid vehicle at the time when the assist mode ends. The inventors of the present application have found that there is a positive correlation between the vehicle speed Vc and the executable period g. Since the travel information associated with the executable period g in the map M is the vehicle speed Vc, the estimation accuracy of the executable period g can be further improved.

[0046] Furthermore, in the control device 20 of the first embodiment, the map M (see FIG. 8) is updated using the driving information in the assist mode when the hybrid vehicle 1 first travels and the executable period g corresponding to the driving information. Therefore, since the map M can be updated using data when the hybrid vehicle 1 first travels, the estimation accuracy of the executable period g can be further improved.

[0047] Furthermore, in the control device 20 of the first embodiment, the setting unit 21 sets the charging torque according to the estimated executable period g. Therefore, when the estimated executable period g is relatively long, the charging torque is set small, so that the secondary battery 18 can be charged while suppressing an increase in the EG torque. On the other hand, when the estimated executable period g is relatively short, the charging torque is set large, so that the amount of charge of the secondary battery 18 can be ensured even if the estimated executable period g is short. That is, it is possible to set an appropriate charging torque from the viewpoints of the load on the engine 11 and the charging efficiency in the charging travel mode.

[0048] <Second embodiment> 11 is an explanatory diagram illustrating the configuration of a hybrid vehicle 1a equipped with a control device 20a of the second embodiment. The control device 20a of the second embodiment is the same as the control device 20 of the first embodiment, except that the control device 20a of the second embodiment further includes a communication unit 29 compared to the control device 20 of the first embodiment.

[0049] The control device 20a includes a communication unit 29 that communicates with the outside of the hybrid vehicle 1a. In the second embodiment, the setting unit 21 can refer to the map M updated using the travel information during the assist mode due to travel of another hybrid vehicle different from the hybrid vehicle 1a (own vehicle) and the executable period g corresponding to the travel information through communication with the outside. That is, the setting unit 21 can acquire data (corresponding to the white circle plot in FIG. 7) that associates the vehicle speed Vc at the end of the assist mode implemented when the other hybrid vehicle traveled with the executable period g thereafter by communicating with the other hybrid vehicle, and estimate the executable period g by referring to the map M updated using the data. Alternatively, the setting unit 21 may transmit data corresponding to a plurality of white circle plots (see FIG. 7) possessed by the hybrid vehicle 1a to an external calculation device, and then receive the map M updated in the external calculation device using the data and data corresponding to the white circle plots due to travel of the other hybrid vehicle, and estimate the executable period g by referring to the map M. In any case, the control device 20a of the second embodiment can refer to the map M updated using data from the traveling of other hybrid vehicles, and therefore can further improve the estimation accuracy of the executable period g. In addition, when the setting unit 21 refers to the map M updated in the external computing device, if the data corresponding to the white circle plots of other hybrid vehicles used to update the map M can be limited to data from traveling around the area in which the hybrid vehicle 1 is currently traveling, then the map M can be updated using such limited data to generate a map M specialized for improving the estimation accuracy of the executable period g when traveling around that area.

[0050] <Third embodiment> The control device of the third embodiment has the same configuration as the control device 20a of the second embodiment, but differs in the type of information exchanged through communication with the outside.

[0051] In the third embodiment, the setting unit 21 can refer to the map M corrected using the other vehicle map referred to by another hybrid vehicle different from the hybrid vehicle 1a through communication with the outside. The other vehicle map corresponds to the map M in the other hybrid vehicle. That is, the setting unit 21 can acquire the other vehicle map by communicating with the other hybrid vehicle, and estimate the executable period g by referring to the map M corrected using the other vehicle map. Alternatively, the setting unit 21 may transmit data corresponding to the map M to an external calculation device, receive the map M corrected by the external calculation device using the map M and the other vehicle map, and estimate the executable period g by referring to the corrected map M. In any case, the control device of the third embodiment can refer to the map M corrected using the other vehicle map referred to by the other hybrid vehicle, and thus the estimation accuracy of the executable period g can be further improved. Furthermore, when the setting unit 21 refers to the map M corrected in an external calculation device, if the other vehicle map used to correct the map M can be limited to the other vehicle map of another hybrid vehicle that has traveled around the area in which the hybrid vehicle 1 is currently traveling, then by correcting the map M using such a limited other vehicle map, it is possible to generate a map M specialized in improving the estimation accuracy of the feasible period g when traveling around that area.

[0052] <Modifications of this embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit and scope of the invention. For example, the following modifications are also possible.

[0053] [Variation 1] In the above embodiment, the control device 20, 20a includes the EG drive control unit 23 and the MG drive control unit 25, but is not limited to this. The control device 20, 20a may not include the EG drive control unit 23 and the MG drive control unit 25. In such a case, the EG drive control unit 23 and the MG drive control unit 25 provided outside the control device 20, 20a in the hybrid vehicle 1, 1a receive the EG torque and the MG torque set by the setting unit 21, and then drive the engine 11 and the motor generator 17 according to the EG torque and the MG torque.

[0054] [Variation 2] In the above embodiment, the travel information associated with the executable period g is the vehicle speed of the hybrid vehicle 1 at the time when the assist mode ends, but is not limited to this. For example, the travel information associated with the executable period g may include the vehicle speed of the hybrid vehicle 1, 1a at the time when the assist mode ends, and may also include other information. Examples of the other information include the vehicle speed at the start of the assist mode, the amount of change in the vehicle speed during the assist mode, and the duration of the assist mode, and it has been found that these pieces of information also have a positive correlation with the executable period g. In such a case, the map used to acquire the executable period g is a map that can acquire the corresponding executable period g when the vehicle speed of the hybrid vehicle 1, 1a at the time when the assist mode ends and the above-mentioned other information are applied. Of course, the travel information collected by the information collecting unit 27 in such a case includes the vehicle speed of the hybrid vehicle 1, 1a at the time when the assist mode ends and the above-mentioned other information. In addition, the above-mentioned other information may also be used to update the map within the vehicle or via communication with the outside.

[0055] [Variation 3] In the above embodiment, the map M is derived by fitting a quadratic curve to the multiple black circle plots shown in Fig. 7 using the least squares method, but the present invention is not limited to this. For example, the map M may be derived by fitting a quadratic curve to the multiple white circle plots shown in Fig. 7 using the least squares method. Alternatively, the map M may be derived by linearly interpolating between the multiple black circle plots shown in Fig. 7.

[0056] Although the present aspect has been described above based on the embodiment and modified examples, the above-mentioned embodiment of the aspect is intended to facilitate understanding of the present aspect and does not limit the present aspect. The present aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents are included in the present aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate.

[0057] The present invention can also be realized in the following forms. [Application example 1] A control device for a hybrid vehicle including an engine and a motor generator as drive sources, and a secondary battery that supplies electric power to the motor generator and stores electric power generated by the motor generator, a setting unit that sets an engine torque output from the engine and a motor generator torque output from the motor generator in accordance with a required torque required for the hybrid vehicle; an information collection unit that collects driving information related to the hybrid vehicle while the hybrid vehicle is running; The setting unit is When an allowable upper limit of the engine torque for which output is permitted is smaller than the required torque, the engine torque is set to be equal to or smaller than the allowable upper limit as an assist mode, and a difference between the engine torque and the required torque is set as the motor generator torque; a control device for a hybrid vehicle, when the allowable upper limit of the engine torque transitions from a state smaller than the required torque to a state larger than the required torque, a sum of a charging torque used to charge the secondary battery and the required torque is set as the engine torque in a charging travel mode, and a negative motor generator torque is set in accordance with the charging torque, and the feasible period is estimated by referring to a map that corresponds the travel information in the assist mode to a period during which the charging travel mode can be implemented. [Application example 2] A control device for a hybrid vehicle according to Application Example 1, The traveling information collected by the information collecting unit includes a vehicle speed of the hybrid vehicle at a time when the assist mode is terminated, A control device for a hybrid vehicle, wherein the driving information associated with the executable period includes a vehicle speed of the hybrid vehicle at a time when the assist mode ends. [Application example 3] The control device for a hybrid vehicle according to the first or second aspect of the present invention, A control device for a hybrid vehicle, wherein the map is updated using the driving information in the assist mode and the executable period corresponding to the driving information when the hybrid vehicle is driven for the first time. [Application example 4] The control device for a hybrid vehicle according to any one of Application Examples 1 to 3, further comprising: A communication unit that communicates with an outside of the hybrid vehicle, A control device for a hybrid vehicle, wherein the setting unit is capable of referring to the map updated using the driving information during the assist mode when another hybrid vehicle is traveling and the executable period corresponding to the driving information via communication with the outside. [Application example 5] The control device for a hybrid vehicle according to any one of Application Examples 1 to 4, further comprising: A communication unit that communicates with an outside of the hybrid vehicle, A control device for a hybrid vehicle, wherein the setting unit is capable of referring to the map corrected using an other vehicle map referred to by another of the hybrid vehicles via communication with the outside. [Application Example 6] A control device for a hybrid vehicle according to any one of Application Examples 1 to 5, A control device for a hybrid vehicle, wherein the setting unit sets the charging torque in accordance with the estimated possible charging period. [Explanation of symbols]

[0058] 1,1a…Hybrid vehicle 11…Engine 12…Gearbox 13…Propeller shaft 14…Differential gear 15…Drive shaft 16…Tire 17...Motor generator 18…Secondary battery 20, 20a...Control device 21. Setting section 23...EG drive control unit 25...MG drive control unit 27…Information Gathering Department 29…Communications Department

Claims

1. A control device for a hybrid vehicle including an engine and a motor generator as drive sources, and a secondary battery that supplies electric power to the motor generator and stores electric power generated by the motor generator, a setting unit that sets an engine torque output from the engine and a motor generator torque output from the motor generator in accordance with a required torque required for the hybrid vehicle; an information collection unit that collects driving information related to the hybrid vehicle while the hybrid vehicle is running; The setting unit is When an allowable upper limit of the engine torque for which output is permitted is smaller than the required torque, the engine torque is set to be equal to or smaller than the allowable upper limit as an assist mode, and a difference between the engine torque and the required torque is set as the motor generator torque; a control device for a hybrid vehicle, when the allowable upper limit of the engine torque transitions from a state smaller than the required torque to a state larger than the required torque, a sum of a charging torque used to charge the secondary battery and the required torque is set as the engine torque in a charging travel mode, and a negative motor generator torque is set in accordance with the charging torque, and the feasible period is estimated by referring to a map that corresponds the travel information in the assist mode to a period during which the charging travel mode can be implemented.

2. The control device for a hybrid vehicle according to claim 1, The traveling information collected by the information collecting unit includes a vehicle speed of the hybrid vehicle at a time when the assist mode is terminated, A control device for a hybrid vehicle, wherein the driving information associated with the executable period includes a vehicle speed of the hybrid vehicle at a time when the assist mode ends.

3. The control device for a hybrid vehicle according to claim 1, A control device for a hybrid vehicle, wherein the map is updated using the driving information in the assist mode and the executable period corresponding to the driving information when the hybrid vehicle is driven for the first time.

4. The control device for a hybrid vehicle according to claim 3, further comprising: A communication unit that communicates with an outside of the hybrid vehicle, A control device for a hybrid vehicle, wherein the setting unit is capable of referring to the map updated using the driving information during the assist mode when another hybrid vehicle is traveling and the executable period corresponding to the driving information via communication with the outside.

5. The control device for a hybrid vehicle according to claim 1, further comprising: A communication unit that communicates with an outside of the hybrid vehicle, A control device for a hybrid vehicle, wherein the setting unit is capable of referring to the map corrected using an other vehicle map referred to by another of the hybrid vehicles via communication with the outside.

6. A control device for a hybrid vehicle according to any one of claims 1 to 5, A control device for a hybrid vehicle, wherein the setting unit sets the charging torque in accordance with the estimated possible charging period.

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