JP2016117374A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid vehicle capable of achieving special traveling in a CD mode and reducing its accompanying uncomfortable feeling that may be provided to a user.SOLUTION: An ECU 26 can select a CD mode or a CS mode, and the start power threshold value of an engine 2 in the CD mode is larger than a threshold in the CS mode. The ECU 26 changes driving force characteristics according to mode switching when a predetermined condition is not met, and does not change the driving force characteristics when the condition is met. When the condition is not met, the ECU 26 changes, in the CD mode, the driving force characteristics between the CD mode and the CS mode so that vehicle driving torque at the same vehicle speed and the same accelerator opening can be larger than in the CS mode.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hybrid vehicle, and more particularly, to a hybrid vehicle including an internal combustion engine, a power storage device, and an electric motor that generates a driving force when supplied with power from the power storage device.

  Japanese Patent Laying-Open No. 2013-252853 (Patent Document 1) discloses a hybrid vehicle having a CD (Charge Depleting) mode and a CS (Charge Sustaining) mode. The CD mode is a mode that actively consumes the SOC (State Of Charge) of the power storage device by actively performing the EV traveling while allowing the HV traveling, and the CS mode is the HV traveling and the EV traveling. In this mode, the SOC is controlled within a predetermined range by appropriately switching the. The EV travel is travel using only the motor generator with the engine stopped, and the HV travel is travel performed by operating the engine. In the CD mode, it is described that the threshold value of the power at which the engine starts is increased as compared with the CS mode (see Patent Document 1).

JP2013-252853A

  In the hybrid vehicle described in Patent Document 1, the difference between the driving in the CD mode and the driving in the CS mode is realized by changing the EV driving opportunity between the CD mode and the CS mode. That is, in the hybrid vehicle described above, in the CD mode, the EV driving opportunity is expanded by increasing the threshold value of the power at which the engine starts compared to the CS mode. And realize the difference in running.

  On the other hand, advances in power electronics technology have improved the performance of motors, inverters, power storage devices, and the like, and increased motor output. With such a technical background, in the hybrid vehicle, the degree of freedom in selecting the driving force source (engine and motor) is high, and in the hybrid vehicle having the CD mode and the CS mode, the user satisfaction particularly in the CD mode. It is hoped that a special run with high degree will be realized.

  Therefore, in order to realize a special running in the CD mode, it is conceivable to change the driving force characteristics of the vehicle between the CD mode and the CS mode. Specifically, when the CD mode is selected, the CD mode and the CS mode are set so that the vehicle driving torque for the same vehicle speed and the same accelerator opening is larger than when the CS mode is selected. It is conceivable to change the driving force characteristics. Thereby, the acceleration performance of EV traveling in the CD mode can be improved, and in the CD mode, a strong acceleration feeling can be obtained by EV traveling while expanding the opportunities for EV traveling. However, a change in driving force characteristics accompanying switching between the CD mode and the CS mode may make the user feel uncomfortable.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a hybrid vehicle that realizes a special running in the CD mode and can reduce the uncomfortable feeling that can be given to the user in accordance with the realization.

  According to the present invention, the hybrid vehicle includes an internal combustion engine, a power storage device, an electric motor that generates a driving force when power is supplied from the power storage device, and a control for selecting one of the CD mode and the CS mode. Device. In each of the CD mode and the CS mode, the control device stops the internal combustion engine and travels by the electric motor according to the traveling state, and the second traveling by operating the internal combustion engine. The travel mode (HV travel) is switched. When the CD mode is selected, the power threshold value for switching from the first travel mode to the second travel mode is larger than the threshold value when the CS mode is selected. The control device changes the driving force characteristics of the vehicle according to the mode switching between the CD mode and the CS mode when the predetermined condition is not satisfied, and switches to the mode switching when the predetermined condition is satisfied. The change of the corresponding driving force characteristic is not implemented. When the predetermined condition is not satisfied, the control device increases the vehicle driving torque for the same vehicle speed and the same accelerator opening when the CD mode is selected than when the CS mode is selected. As described above, the driving force characteristics are changed between the CD mode and the CS mode.

  In this hybrid vehicle, the EV driving opportunities in the CD mode are expanded by setting the threshold values as described above, and the EV driving force in the CD mode is changed by changing the driving force characteristics of the vehicle as described above in accordance with the mode switching. Driving acceleration performance is improved. Thereby, in the CD mode, it is possible to obtain a strong acceleration feeling by EV traveling while expanding the opportunities for EV traveling. Here, in this hybrid vehicle, the change in the driving force characteristic accompanying the mode switching is set by setting the case where the change in the driving force characteristic accompanying the mode switching can give the user a sense of incongruity, etc. However, when the user may feel a sense of incongruity, the driving force characteristics can be changed according to the mode switching. Therefore, according to this hybrid vehicle, it is possible to realize a special running in the CD mode and to reduce the uncomfortable feeling given to the user in accordance with the realization.

  Preferably, the control device further includes a vehicle speed at the same accelerator opening degree when the CD mode is selected in a range where the vehicle driving torque is below a predetermined upper limit than when the CS mode is selected. The driving force characteristics of the vehicle are changed between the CD mode and the CS mode so that the decrease in the vehicle driving torque in accordance with the increase in the driving force is reduced.

  In this hybrid vehicle, when the CD mode is selected, a decrease in the vehicle driving torque according to the increase in the vehicle speed is small, so that a sense of acceleration can be obtained. Therefore, according to this hybrid vehicle, special running in the CD mode can be realized.

  Preferably, the control device responds to the mode switching when the vehicle driving torque is smaller than a predetermined value when the change of the driving force characteristic according to the mode switching is not performed when a predetermined condition is satisfied. Change the driving force characteristics.

  By adopting such a configuration, it is possible to reduce a sense of discomfort that can be given to the user as the driving force characteristics change according to mode switching. Note that the predetermined value is a small value that does not give the user a sense of incongruity even when the vehicle driving torque changes due to a change in driving force characteristics according to mode switching.

  Preferably, the predetermined condition includes that it is determined that the vehicle is traveling on a curve by a predetermined curve traveling determination.

  Preferably, the predetermined condition includes switching between the first traveling mode (EV traveling) and the second traveling mode (HV traveling) by changing the driving force characteristic according to the mode switching.

Preferably, the predetermined condition includes that the reverse range is selected.
Preferably, the hybrid vehicle further includes an input device for the user to select either the CD mode or the CS mode. The predetermined condition includes that mode switching is performed regardless of the operation of the input device.

  Preferably, the predetermined condition includes that the vehicle is determined to be in a stopped state on the slope by a predetermined slope balance determination.

  Preferably, the predetermined condition includes that it is determined that the vehicle is traveling in a constant state by a predetermined steady traveling determination.

  Preferably, the predetermined condition includes that it is determined by a predetermined coasting determination that the vehicle is traveling in a coasting state.

Preferably, the predetermined condition includes that the vehicle is accelerating.
Preferably, the predetermined condition includes that the vehicle is determined to be over the step by the predetermined step overcoming determination.

  Preferably, the predetermined condition includes that the change amount of the accelerator opening after the mode switching is performed is smaller than the predetermined amount.

  If the driving force characteristics are changed due to mode switching when each of the above conditions is satisfied, the change in the driving force can give the user a sense of incongruity. In this case, the driving force characteristics are not changed according to the mode switching. Therefore, it is possible to reduce the uncomfortable feeling that can be given to the user when the special running in the CD mode is realized.

  Preferably, the hybrid vehicle further includes a charging mechanism for charging the power storage device using electric power from a power source outside the vehicle.

  According to this hybrid vehicle, it is possible to achieve a strong acceleration feeling in EV traveling while improving fuel efficiency in the CD mode using electric power supplied from a power source outside the vehicle.

  According to the present invention, it is possible to provide a hybrid vehicle that realizes a special running in the CD mode and can reduce the uncomfortable feeling that can be given to the user in accordance with the realization.

1 is a block diagram illustrating an overall configuration of a hybrid vehicle according to a first embodiment of the present invention. It is a figure for demonstrating CD mode and CS mode. It is a figure for demonstrating the view of the driving force characteristic in each of CS mode and CD mode. It is a flowchart for demonstrating the process sequence of vehicle drive torque (request value) calculation performed by ECU. It is the figure which showed an example of the driving force map for CS mode. It is the figure which showed an example of the driving force map for CD modes. 10 is a flowchart for illustrating a processing procedure for calculating a vehicle driving torque in the second embodiment. 12 is a flowchart for illustrating a processing procedure for calculating a vehicle driving torque in the third embodiment. 14 is a flowchart for illustrating a processing procedure for calculating a vehicle driving torque in the fourth embodiment. 10 is a flowchart for illustrating a processing procedure for calculating a vehicle driving torque in the fifth embodiment. 18 is a flowchart for illustrating a processing procedure for calculating a vehicle driving torque in the sixth embodiment. 18 is a flowchart for illustrating a processing procedure for calculating a vehicle driving torque in the seventh embodiment. 20 is a flowchart for illustrating a processing procedure for calculating vehicle driving torque in the eighth embodiment. FIG. 38 is a flowchart for illustrating a procedure for calculating vehicle driving torque in the ninth embodiment. 42 is a flowchart for illustrating a processing procedure for calculating vehicle driving torque in the tenth embodiment. FIG. 38 is a flowchart for illustrating a procedure for calculating vehicle driving torque in the eleventh embodiment. FIG. 38 is a flowchart for illustrating a procedure for calculating vehicle driving torque in the twelfth embodiment. It is a flowchart for demonstrating the process sequence of vehicle drive torque calculation in a modification. It is a block diagram explaining the modification of the whole structure of a hybrid vehicle.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, a plurality of embodiments will be described. However, it is planned from the beginning of the application to appropriately combine the configurations described in the embodiments. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is a block diagram for illustrating the overall configuration of a hybrid vehicle according to the first embodiment of the present invention. Referring to FIG. 1, hybrid vehicle 100 includes an engine 2, a drive device 22, a transmission gear 8, a drive shaft 12, wheels 14, a power storage device 16, an ECU (Electronic Control Unit) 26, a mode, and the like. And a switch (mode SW) 28. The hybrid vehicle 100 further includes a power converter 23 and a connection unit 24.

  The engine 2 is an internal combustion engine that outputs power by converting thermal energy from combustion of fuel into kinetic energy of a moving element such as a piston or a rotor. As the fuel for the engine 2, hydrocarbon fuels such as gasoline, light oil, ethanol, liquid hydrogen, and natural gas, or liquid or gaseous hydrogen fuel are suitable.

  Drive device 22 includes a power split device 4, motor generators 6, 10, and power converters 18, 20. Motor generators 6 and 10 are AC rotating electric machines, for example, three-phase AC synchronous motors in which permanent magnets are embedded in a rotor. The motor generator 6 is used as a generator driven by the engine 2 via the power split device 4 and also as an electric motor for starting the engine 2. The motor generator 10 mainly operates as an electric motor and drives the drive shaft 12. On the other hand, when braking the vehicle or reducing acceleration on a downward slope, the motor generator 10 operates as a generator and performs regenerative power generation.

  The power split device 4 includes, for example, a planetary gear mechanism having three rotation shafts of a sun gear, a carrier, and a ring gear. Power split device 4 divides the driving force of engine 2 into power transmitted to the rotation shaft of motor generator 6 and power transmitted to transmission gear 8. The transmission gear 8 is connected to a drive shaft 12 for driving the wheels 14. Transmission gear 8 is also coupled to the rotating shaft of motor generator 10.

  The power storage device 16 is a rechargeable DC power supply, and includes, for example, a secondary battery such as a nickel metal hydride battery or a lithium ion battery, a large-capacity capacitor, and the like. The power storage device 16 supplies power to the power converters 18 and 20. The power storage device 16 is charged by receiving the generated power when the motor generator 6 and / or 10 generates power. Furthermore, the power storage device 16 can be charged by receiving electric power supplied from a power source outside the vehicle through the connection unit 24.

  The state of charge of power storage device 16 is indicated by, for example, an SOC that represents the current amount of power stored in the fully charged state of power storage device 16 as a percentage. The SOC is calculated based on, for example, the output voltage and / or input / output current of the power storage device 16 detected by a voltage sensor and / or current sensor (not shown). The SOC may be calculated by an ECU provided separately in the power storage device 16, or may be calculated by the ECU 26 based on the output voltage of the power storage device 16 and / or the detected value of the input / output current.

  Power converter 18 performs bidirectional DC / AC power conversion between motor generator 6 and power storage device 16 based on a control signal received from ECU 26. Similarly, power converter 20 performs bidirectional DC / AC power conversion between motor generator 10 and power storage device 16 based on a control signal received from ECU 26. Thereby, motor generators 6 and 10 can output a positive torque for operating as an electric motor or a negative torque for operating as a generator, with the transfer of electric power to and from power storage device 16. . Power converters 18 and 20 are constituted by inverters, for example. It is also possible to arrange a boost converter for DC voltage conversion between power storage device 16 and power converters 18 and 20.

  The power converter 23 converts electric power from an external power supply (not shown) outside the vehicle that is electrically connected to the connection unit 24 into a voltage level of the power storage device 16 and outputs the voltage level to the power storage device 16 (hereinafter, external). The charging of the power storage device 16 by the power source is also referred to as “external charging”). The power converter 23 includes, for example, a rectifier and an inverter. Note that the method of receiving power from the external power source is not limited to contact power reception using the connection unit 24, and may receive power from the external power source in a non-contact manner using a power receiving coil or the like instead of the connection unit 24.

  The ECU 26 includes a CPU (Central Processing Unit), a storage device, an input / output buffer, and the like (all not shown), and controls each device in the hybrid vehicle 100. Note that these controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuit).

  As the main control of the ECU 26, the ECU 26 calculates a vehicle driving torque (required value) based on the vehicle speed and the accelerator opening corresponding to the operation amount of the accelerator pedal, and the vehicle driving power based on the calculated vehicle driving torque. (Required value) is calculated. Then, ECU 26 further calculates the required charging power of power storage device 16 based on the SOC of power storage device 16, and generates power obtained by adding the required charging power to vehicle drive power (hereinafter referred to as “vehicle power”). The engine 2 and the drive device 22 are controlled.

  When the vehicle power is low, the ECU 26 controls the driving device 22 so that the engine 2 is stopped and the motor generator 10 travels only (EV travel). When the vehicle power increases, the ECU 26 controls the engine 2 and the drive device 22 so that the engine 2 operates to travel (HV traveling).

  Here, the ECU 26 switches the SOC by appropriately switching between the CD mode in which the SOC of the power storage device 16 is actively consumed by allowing the EV running while allowing the HV running, and the HV running and the EV running as appropriate. The traveling control for controlling the traveling of the vehicle is executed by selectively applying the CS mode for controlling to a predetermined range.

  FIG. 2 is a diagram for explaining the CD mode and the CS mode. Referring to FIG. 2, it is assumed that traveling is started in the CD mode after power storage device 16 is fully charged (SOC = MAX) by external charging by an external power source.

  The CD mode is a mode in which the SOC of the power storage device 16 is actively consumed. Basically, the power stored in the power storage device 16 (mainly electric energy by external charging) is consumed. When traveling in the CD mode, the engine 2 does not operate in order to maintain the SOC. Specifically, for example, when the CD mode is selected, the required charging power of power storage device 16 is set to zero. As a result, the SOC may temporarily increase due to the regenerative power collected when the vehicle decelerates or the power generated by the operation of the engine 2, but as a result, the rate of discharge rather than charging As a whole, the SOC decreases as the travel distance increases.

  The CS mode is a mode for controlling the SOC of the power storage device 16 within a predetermined range. As an example, when the SOC decreases to a predetermined value Stg indicating a decrease in SOC at time t1, the CS mode is selected, and the subsequent SOC is maintained within a predetermined range. Specifically, when the SOC decreases, the engine 2 operates (HV traveling), and when the SOC increases, the engine 2 stops (EV traveling). That is, in the CS mode, the engine 2 operates to maintain the SOC.

  In this hybrid vehicle 100, when the vehicle power is smaller than a predetermined engine start threshold value, the engine 2 is stopped and the motor generator 10 travels (EV travel). On the other hand, when the vehicle power exceeds the engine start threshold value, the engine 2 is operated to travel (HV traveling). In the HV traveling, the hybrid vehicle 100 travels using the driving force of the engine 2 in addition to the driving force of the motor generator 10 or instead of the motor generator 10. The electric power generated by the motor generator 6 during the HV traveling due to the operation of the engine 2 is directly supplied to the motor generator 10 or stored in the power storage device 16.

  Here, the engine start threshold value in the CD mode is larger than the engine start threshold value in the CS mode. That is, the region where hybrid vehicle 100 travels in EV in the CD mode is larger than the region where hybrid vehicle 100 travels in EV in CS mode. Thereby, in the CD mode, the frequency at which the engine 2 is started is suppressed, and the opportunity of EV traveling is expanded as compared with the CS mode. On the other hand, in the CS mode, control is performed so that hybrid vehicle 100 travels efficiently using both engine 2 and motor generator 10.

  Even in the CD mode, the engine 2 operates if the vehicle power (equal to the vehicle drive power) exceeds the engine start threshold value. Even if the vehicle power does not exceed the engine start threshold value, the operation of the engine 2 may be allowed, such as when the engine 2 or the exhaust catalyst is warmed up. On the other hand, even in the CS mode, the engine 2 stops when the SOC increases. That is, the CD mode is not limited to the EV travel that travels while the engine 2 is always stopped, and the CS mode is not limited to the HV travel that travels while the engine 2 is always operated. In both the CD mode and the CS mode, EV running and HV running are possible.

  Referring to FIG. 1 again, the mode switch 28 is an input device that enables the user to select either the CD mode or the CS mode. Mode switch 28 outputs signal MD to ECU 26 in response to the mode selected by the user's operation. The mode switch 28 is not essential.

  The ECU 26 selects the CS mode when the CD mode is selected based on the SOC or in response to the operation of the mode switch 28 by the driver when a predetermined condition described later is not satisfied. The driving force characteristics of the vehicle are changed between the CD mode and the CS mode so that the vehicle driving torque with respect to the same vehicle speed and the same accelerator opening becomes larger than when the vehicle is present. By changing the driving force characteristics as described above, in the CD mode, it is possible to obtain a strong acceleration feeling in the EV running while expanding the EV running opportunities, and it is possible to realize a special running in the CD mode. On the other hand, when a predetermined condition (described later) is satisfied, the ECU 26 assumes that the change in the driving force characteristic accompanying the mode switching may give the user a sense of incongruity, and changes the driving force characteristic according to the mode switching. Not implemented. These will be described in detail below.

  FIG. 3 is a diagram for explaining the concept of driving force characteristics in each of the CS mode and the CD mode. Referring to FIG. 3, the horizontal axis indicates the vehicle speed, and the vertical axis indicates the driving torque of the vehicle. A curve PL1 indicates a start threshold value (equal power line) of the engine 2 when the CS mode is selected, and a curve PL2 indicates a start threshold value (etc.) of the engine 2 when the CD mode is selected. Power line). As described above, the starting power threshold value of engine 2 when the CD mode is selected is larger than the starting power threshold value when CS mode is selected.

  Line L1 shows the driving force characteristic of the vehicle when the accelerator opening is X% when the CS mode is selected. That is, when the CS mode is selected and the accelerator opening is X%, the vehicle driving torque (required value) is determined according to this line L1.

  A line L2 indicates the driving force characteristic of the vehicle when the accelerator opening is X% when the CD mode is selected. That is, when the CD mode is selected and the accelerator opening is X%, the vehicle driving torque (required value) is determined according to this line L2.

  The driving force characteristics when the accelerator opening is X% are not limited to those indicated by lines L1 and L2, but in hybrid vehicle 100 according to the first embodiment, CD mode is selected. When the vehicle is in the driving mode, the driving force characteristics are changed between the CD mode and the CS mode so that the vehicle driving torque for the same vehicle speed and the same accelerator opening becomes larger than when the CS mode is selected.

  When the CS mode is selected, as shown by the line L1, the driving torque characteristic is controlled so that the engine 2 does not start until the operating point indicated by the point S1 is reached by suppressing the driving torque according to the increase in the vehicle speed. Is set. For the purpose of obtaining a strong acceleration feeling during EV traveling, if a driving force characteristic that increases the driving torque to the extent indicated by the line L2 is set, the engine 2 starts at an early stage at the operating point indicated by the point S2. EV driving opportunities are significantly reduced.

  On the other hand, when the CD mode is selected, as described above, the starting power threshold value of engine 2 is larger than the starting power threshold value when CS mode is selected. Specifically, engine 2 does not start until vehicle power (vehicle drive power) reaches a line indicated by curve PL2. Therefore, in hybrid vehicle 100 according to the first embodiment, when the CD mode is selected, the vehicle driving torque for the same vehicle speed and the same accelerator opening is greater than when CS mode is selected, as indicated by line L2. The driving force characteristic is set so as to increase. When the CD mode is selected, the engine 2 is not started until the operating point indicated by the point S3 is reached even if the driving force characteristic according to the line L2 is given. Thereby, when the CD mode is selected, a strong acceleration torque in the EV traveling along the line L2 can be realized while expanding the EV traveling opportunity (point S2 → point S3).

  Referring to FIG. 1 again, as described above, the ECU 26 does not change the driving force characteristics according to the mode switching when the predetermined condition is satisfied. That is, as described with reference to FIG. 3, by changing the driving force characteristics accompanying the mode switching, it is possible to obtain a strong acceleration feeling in EV traveling while expanding the opportunities for EV traveling in the CD mode. On the other hand, there is a possibility that the change in the driving force characteristics accompanying the mode switching may give the user a feeling of strangeness. Specifically, when the driving force characteristic change associated with the mode switching is performed during curve travel, the change in the driving force associated with the mode switching may give the user a sense of incongruity.

  Therefore, in hybrid vehicle 100 according to the first embodiment, when it is determined that the vehicle is traveling on a curve according to a predetermined curve traveling determination, the driving force characteristics are not changed according to the mode switching. Is. Thereby, the uncomfortable feeling given to the user by the change of the driving force characteristics accompanying the mode switching can be reduced.

  FIG. 4 is a flowchart for explaining a processing procedure for calculating the vehicle driving torque (required value) executed by the ECU 26 shown in FIG. The process shown in this flowchart is called from the main routine and executed every predetermined time or when a predetermined condition is satisfied.

  Referring to FIG. 4, ECU 26 receives detected values of the accelerator opening and the vehicle speed (step S10). The accelerator opening is detected by an accelerator opening sensor (not shown), and the vehicle speed is detected by a vehicle speed sensor that detects the vehicle speed by detecting the rotational speed of the axle, for example.

  Next, the ECU 26 determines whether or not the mode has been switched between the CD mode and the CS mode (step S20). For example, the mode can be switched based on the SOC as shown in FIG. 2 or according to the operation of the mode switch 28 (FIG. 1) by the user.

  If it is determined in step S20 that the mode has been switched (YES in step S20), ECU 26 determines whether or not the vehicle is traveling in a curve based on a predetermined curve traveling determination (step S30). For example, when the detected value of a steering angle sensor or acceleration sensor (detecting acceleration in the vehicle lateral direction) not shown is equal to or greater than a certain value and the vehicle speed or accelerator opening is equal to or greater than a certain value, it is determined that the vehicle is traveling in a curve. Can be done.

  If it is determined in step S30 that the vehicle is not traveling on a curve (NO in step S30), the ECU 26 determines whether or not the CD mode is selected (step S40). Here, it may be determined whether or not the CS mode is selected. If it is determined that the CD mode is selected (YES in step S40), the ECU 26 uses the driving force map A for CD mode (described later) and the accelerator operation amount detected in step S10 and Based on the vehicle speed, the required driving torque of the vehicle (the required value or target value of the vehicle driving torque) is calculated (step S50).

  On the other hand, if it is determined in step S40 that the CS mode is selected (NO in step S40), ECU 26 uses the driving force map B for CS mode (described later) to detect the accelerator detected in step S10. A required driving torque is calculated based on the opening and the vehicle speed (step S60).

  FIG. 5 is a diagram showing an example of the driving force map B for the CS mode. Referring to FIG. 5, the horizontal axis indicates the vehicle speed, and the vertical axis indicates the driving torque of the vehicle. Line R indicates the rated output line. Line L11 shows the driving force characteristic of the vehicle when the accelerator opening is X1%, and lines L12 and L13 show the driving force characteristics when the accelerator opening is X2% and X3% (X1> X2> X3), respectively. Indicates. Although not shown when the accelerator opening is other than X1%, X2%, or X3%, the line indicating the driving force characteristic shifts in the upper right direction of the figure as the accelerator opening increases.

  On the other hand, FIG. 6 is a diagram showing an example of the driving force map A for the CD mode. FIG. 6 corresponds to FIG. Referring to FIG. 6, line L21 indicates the driving force characteristic of the vehicle when the accelerator opening is X1%, and lines L22 and L23 indicate the driving force characteristics when the accelerator opening is X2% and X3%, respectively. Indicates.

  With reference to FIGS. 5 and 6, as can be seen from the comparison at the same accelerator opening (the comparison between the line L11 and the line L21, the comparison between the line L12 and the line L22, the comparison between the line L13 and the line L23), When the mode is selected (FIG. 6), the vehicle is switched between the CD mode and the CS mode so that the vehicle driving torque for the same vehicle speed and the same accelerator opening is greater than when the CS mode is selected (FIG. 5). The driving force characteristic is changed. Thereby, in the CD mode, it is possible to obtain a strong acceleration feeling by EV traveling while expanding the opportunities for EV traveling.

  As shown in FIGS. 5 and 6, in the range where the vehicle driving torque falls below the rated output line R, the CD mode selection (FIG. 6) is the same as the CS mode selection (FIG. 5). It is preferable to change the driving force characteristics in the CD mode and the CS mode so that the decrease in the vehicle driving torque corresponding to the increase in the vehicle speed at the accelerator opening is reduced. Specifically, for example, when comparing the line L12 (CS mode) and the line L22 (CD mode) of the same accelerator opening, the slope of the line L22 in the CD mode (the vehicle driving torque corresponding to the increase in vehicle speed). The degree of decrease) is smaller than the slope of the line L12 in the CS mode. Thereby, when the CD mode is selected, a sense of acceleration (a feeling of maintaining the driving force with respect to an increase in vehicle speed) can be obtained compared to when the CS mode is selected.

  Referring to FIG. 4 again, if it is determined in step S30 that the vehicle is traveling on a curve (YES in step S30), ECU 26 uses the driving force map before the mode switching to open the accelerator detected in step S10. The required driving torque of the vehicle is calculated based on the degree and the vehicle speed (step S70). That is, when it is determined that the vehicle is traveling on a curve, the change in the driving force characteristic accompanying the mode switching can give the user a sense of incongruity, so the driving force characteristic changing according to the mode switching is not performed. The

  If it is determined in step S20 that there is no mode switching (NO in step S20), the ECU 26 determines the driving force map for the current mode (the driving force map A if the current mode is the CD mode, the current state). If the mode is the CS mode, the required driving torque of the vehicle is calculated based on the accelerator opening and the vehicle speed detected in step S10 using the driving force map B) (step S80).

  As described above, in the first embodiment, the EV driving opportunity in the CD mode is expanded, and the EV driving acceleration performance in the CD mode is improved by changing the driving force characteristics of the vehicle according to the mode switching. Is done. Thereby, in the CD mode, it is possible to obtain a strong acceleration feeling by EV traveling while expanding the opportunities for EV traveling. Here, during driving on a curve, the change in the driving force characteristics accompanying the mode switching can give the user a sense of incongruity, so that the driving force characteristics are not changed according to the mode switching. Therefore, according to the first embodiment, the special running in the CD mode can be realized, and the uncomfortable feeling given to the user in accordance with the realization can be reduced.

[Embodiment 2]
If the driving force characteristic of the vehicle is changed in accordance with mode switching during reverse travel, the user may feel uncomfortable. Therefore, in the hybrid vehicle according to the second embodiment, when the mode is switched while the reverse range (R range) is selected, the driving force characteristics are not changed according to the mode switching.

  The overall configuration of the hybrid vehicle according to the second embodiment is the same as that of hybrid vehicle 100 shown in FIG.

  FIG. 7 is a flowchart for illustrating a procedure of required drive torque switching processing executed by ECU 26 in the second embodiment. Referring to FIG. 7, this flowchart includes step S31 instead of step S30 in the flowchart shown in FIG.

  That is, if it is determined in step S20 that the mode has been switched (YES in step S20), ECU 26 determines whether or not the reverse range (R range) is selected (step S31). If it is determined that a range other than the reverse range is selected (NO in step S31), the process proceeds to step S40. Step S40 and subsequent steps S50 and S60 are as described in FIG.

  On the other hand, if it is determined in step S31 that the reverse range is selected (YES in step S31), the process proceeds to step S70, and the required driving torque is calculated using the driving force map before the mode switching. In other words, if it is determined that the reverse range is selected, the change in the driving force characteristics accompanying the mode switching can give the user a sense of incongruity, so the driving force characteristics are not changed according to the mode switching. It is said.

  As described above, in the second embodiment, during reverse travel, the change in the driving force characteristics accompanying the mode switching can give the user a sense of incongruity. It is supposed to be implemented. Therefore, according to the second embodiment, special running in the CD mode can be realized, and the uncomfortable feeling given to the user accompanying the realization can be reduced.

[Embodiment 3]
The mode switching between the CD mode and the CS mode is automatically performed regardless of the operation of the mode switch 28, for example, when the user performs the operation of the mode switch 28 or when the SOC of the power storage device 16 decreases. May be. When the mode switching is automatically performed regardless of the user operation, the change of the driving force characteristics according to the mode switching can give the user a sense of incongruity.

  Therefore, in the hybrid vehicle according to the third embodiment, when the mode switching is automatically performed regardless of the operation of mode switch 28, the driving force characteristics are not changed according to the mode switching. In addition, the automatic mode switching is performed in cooperation with a car navigation device or the like (not shown) in addition to the case where the mode is automatically switched from the CD mode to the CS mode according to the decrease in the SOC of the power storage device 16 as described above. This may include a case where the engine 2 is automatically switched to the CS mode when traveling on an expressway with good fuel efficiency.

  The overall configuration of the hybrid vehicle according to the third embodiment is the same as that of hybrid vehicle 100 shown in FIG.

  FIG. 8 is a flowchart for illustrating a procedure of required drive torque switching processing executed by ECU 26 in the third embodiment. Referring to FIG. 8, this flowchart includes step S32 instead of step S30 in the flowchart shown in FIG.

  That is, if it is determined in step S20 that the mode has been switched (YES in step S20), ECU 26 determines whether or not the mode has been automatically switched (step S32). For example, when the mode is switched without the user operating the mode switch 28, it can be determined that the mode has been switched automatically.

  If it is determined in step S32 that the mode is not automatically switched, that is, if the mode switch 28 is operated by the user (NO in step S32), the process proceeds to step S40. Migrated. Step S40 and subsequent steps S50 and S60 are as described in FIG.

  On the other hand, if it is determined in step S32 that the mode has been automatically switched (YES in step S32), the process proceeds to step S70, and the required driving torque is calculated using the driving force map before the mode switching. The That is, when the mode is switched automatically, not by the user's operation of the mode switch 28, the change of the driving force characteristics accompanying the mode switching can give the user a sense of incongruity, so that The driving force characteristic is not changed.

  As described above, in the third embodiment, when mode switching is performed automatically, a change in driving force characteristics accompanying mode switching can give the user a sense of incongruity, so driving according to mode switching is possible. Changes in force characteristics are not implemented. Therefore, according to the third embodiment, a special running in the CD mode can be realized, and the uncomfortable feeling given to the user in accordance with the realization can be reduced.

[Embodiment 4]
When the user operates the accelerator pedal on a hill and the vehicle is stopped, the accelerator opening in that state is automatically maintained, or the brake pressure is automatically applied for a short time even if the brake is turned off when the hill starts. If the driving force characteristic of the vehicle is changed in accordance with the mode switching during “while balancing on a slope” such as when holding the vehicle at the time, there is a possibility that the user will feel uncomfortable. Therefore, in the hybrid vehicle according to the fourth embodiment, when it is determined that the vehicle is “on the slope balance” by the predetermined slope balance determination, the driving force characteristics are not changed according to the mode switching.

  The overall configuration of the hybrid vehicle according to the fourth embodiment is the same as that of hybrid vehicle 100 shown in FIG.

  FIG. 9 is a flowchart for illustrating a procedure of required drive torque switching processing executed by ECU 26 in the fourth embodiment. Referring to FIG. 9, this flowchart includes step S33 instead of step S30 in the flowchart shown in FIG.

  That is, if it is determined in step S20 that the mode has been switched (YES in step S20), the ECU 26 determines whether or not the hill is being balanced by a predetermined hill balance determination (step S33). For example, when the vehicle speed is below a certain level and the output of a gradient sensor (not shown) is above a certain level, or when the vehicle speed is below a certain level and the accelerator opening is above a certain level, etc. It can be determined that there is.

  If it is determined in step S33 that the road is not balanced (NO in step S33), the process proceeds to step S40. Step S40 and subsequent steps S50 and S60 are as described in FIG.

  On the other hand, if it is determined in step S33 that the road is being balanced (YES in step S33), the process proceeds to step S70, and the required driving torque is calculated using the driving force map before the mode switching. That is, during the hill balance, the change in the driving force characteristics accompanying the mode switching can give the user a sense of incongruity, so that the driving force characteristics are not changed according to the mode switching.

  As described above, in the fourth embodiment, the change in the driving force characteristic accompanying the mode switching can give the user a sense of incongruity during the balance of the slope, so that the change of the driving force characteristic according to the mode switching is not changed. It is supposed to be implemented. Therefore, according to the fourth embodiment, the special running in the CD mode can be realized, and the uncomfortable feeling given to the user in accordance with the realization can be reduced.

[Embodiment 5]
If the driving force characteristic of the vehicle is changed in accordance with mode switching during steady driving on an expressway or the like, there is a possibility that the user will feel uncomfortable. Therefore, in the hybrid vehicle according to the fifth embodiment, when it is determined that the vehicle is in steady driving based on the predetermined steady driving determination, the driving force characteristics are not changed according to the mode switching.

  The overall configuration of the hybrid vehicle according to the fifth embodiment is the same as that of hybrid vehicle 100 shown in FIG.

  FIG. 10 is a flowchart for illustrating the procedure of the required drive torque switching process executed by ECU 26 in the fifth embodiment. Referring to FIG. 10, this flowchart includes step S34 instead of step S30 in the flowchart shown in FIG.

  That is, if it is determined in step S20 that the mode has been switched (YES in step S20), the ECU 26 determines whether or not the vehicle is in steady running based on a predetermined steady running decision (step S34). For example, when the fluctuation range of the accelerator opening is equal to or less than a certain value, the vehicle speed is equal to or greater than a certain value, or the detection value of an acceleration sensor (detecting acceleration in the vehicle longitudinal direction) not illustrated is equal to or less than a certain value, When established, it can be determined that the vehicle is in steady running.

  If it is determined in step S34 that the vehicle is not in steady running (NO in step S34), the process proceeds to step S40. Step S40 and subsequent steps S50 and S60 are as described in FIG.

  On the other hand, if it is determined in step S34 that the vehicle is in steady running (YES in step S34), the process proceeds to step S70, and the required driving torque is calculated using the driving force map before mode switching. That is, during steady running, the change in the driving force characteristics accompanying the mode switching can give the user a sense of incongruity, and therefore the driving force characteristics are not changed according to the mode switching.

  As described above, in the fifth embodiment, the change in the driving force characteristics accompanying the mode switching can give the user a sense of incongruity during the steady running, so that the driving force characteristics are not changed according to the mode switching. It is supposed to be implemented. Therefore, according to the fifth embodiment, the special running in the CD mode can be realized, and the uncomfortable feeling given to the user in accordance with the realization can be reduced.

[Embodiment 6]
If the driving force characteristics of the vehicle are changed according to mode switching during coasting where neither acceleration by power nor deceleration by braking is applied, there is a possibility that the user will feel uncomfortable. Therefore, in the hybrid vehicle according to the sixth embodiment, when it is determined that the vehicle is coasting by a predetermined coasting determination, the driving force characteristics are not changed according to the mode switching.

  The overall configuration of the hybrid vehicle according to the sixth embodiment is the same as that of hybrid vehicle 100 shown in FIG.

  FIG. 11 is a flowchart for illustrating a procedure of required drive torque switching processing executed by ECU 26 in the sixth embodiment. Referring to FIG. 11, this flowchart includes step S35 instead of step S30 in the flowchart shown in FIG.

  That is, when it is determined in step S20 that the mode has been switched (YES in step S20), ECU 26 determines whether or not the vehicle is coasting based on a predetermined coasting determination (step S35). For example, it can be determined that the vehicle is coasting when the accelerator opening is equal to or less than a certain value and the vehicle speed is equal to or greater than a certain value.

  If it is determined in step S35 that the vehicle is not coasting (NO in step S35), the process proceeds to step S40. Step S40 and subsequent steps S50 and S60 are as described in FIG.

  On the other hand, if it is determined in step S35 that the vehicle is coasting (YES in step S35), the process proceeds to step S70, and the required driving torque is calculated using the driving force map before mode switching. That is, during coasting, the change in the driving force characteristics accompanying the mode switching can give the user a sense of incongruity, so the driving force characteristics are not changed according to the mode switching.

  As described above, in the sixth embodiment, during the coasting, the change in the driving force characteristics accompanying the mode switching can give the user a sense of incongruity, so the driving force characteristics are not changed according to the mode switching. It is said. Therefore, according to the sixth embodiment, the special running in the CD mode can be realized, and the uncomfortable feeling given to the user in accordance with the realization can be reduced.

[Embodiment 7]
It is desirable not to change the driving force characteristic of the vehicle during acceleration such as when the vehicle ahead is overtaking. For example, if the mode is switched from the CD mode to the CS mode during acceleration, the user may feel uncomfortable with a decrease in driving torque accompanying the mode switching. Therefore, in the hybrid vehicle according to the seventh embodiment, when it is determined that the vehicle is accelerating, the driving force characteristics are not changed according to the mode switching.

  The overall configuration of the hybrid vehicle according to the seventh embodiment is the same as that of hybrid vehicle 100 shown in FIG.

  FIG. 12 is a flowchart for illustrating a procedure of required drive torque switching processing executed by ECU 26 in the seventh embodiment. Referring to FIG. 12, this flowchart includes step S36 instead of step S30 in the flowchart shown in FIG.

  That is, when it is determined in step S20 that the mode has been switched (YES in step S20), ECU 26 determines whether or not acceleration is being performed (step S36). For example, it can be determined that the vehicle is accelerating when the increase rate of the accelerator opening is equal to or greater than a certain value, or when the detection value of an acceleration sensor (detecting acceleration in the vehicle longitudinal direction) not illustrated is equal to or greater than a certain value.

  If it is determined in step S36 that the vehicle is not accelerating (NO in step S36), the process proceeds to step S40. Step S40 and subsequent steps S50 and S60 are as described in FIG.

  On the other hand, if it is determined in step S36 that the vehicle is accelerating (YES in step S36), the process proceeds to step S70, and the required driving torque is calculated using the driving force map before mode switching. That is, during acceleration, the change in driving force characteristics accompanying the mode switching can give the user a sense of incongruity, so that the driving force characteristics are not changed according to the mode switching.

  As described above, in the seventh embodiment, during acceleration, a change in the driving force characteristic accompanying the mode switching can give the user a sense of incongruity, so the driving force characteristic is not changed according to the mode switching. It is said. Therefore, according to the seventh embodiment, the special running in the CD mode can be realized, and the uncomfortable feeling given to the user in accordance with the realization can be reduced.

[Embodiment 8]
When the user is operating the accelerator pedal appropriately and the vehicle is going over a step (during step over), the user may feel uncomfortable if the driving force characteristic of the vehicle is changed according to mode switching. . Therefore, in the hybrid vehicle according to the eighth embodiment, when it is determined that the vehicle is over the step as described above based on the predetermined step overcoming determination, the driving force characteristic is not changed according to the mode switching. It is said.

  The overall configuration of the hybrid vehicle according to the eighth embodiment is the same as that of hybrid vehicle 100 shown in FIG.

  FIG. 13 is a flowchart for illustrating the procedure of the required drive torque switching process executed by ECU 26 in the eighth embodiment. Referring to FIG. 13, this flowchart includes step S37 in place of step S30 in the flowchart shown in FIG.

  That is, if it is determined in step S20 that the mode has been switched (YES in step S20), the ECU 26 determines whether or not the vehicle has been stepped over by a predetermined step overstep determination (step S37). For example, when the accelerator opening is above a certain level and the vehicle speed is below a certain level, or when the rate of change of the accelerator opening is below a certain level and the vehicle speed is below a certain level, the vehicle is over the step. Can be determined.

  If it is determined in step S37 that the vehicle is not overstepping (NO in step S37), the process proceeds to step S40. Step S40 and subsequent steps S50 and S60 are as described in FIG.

  On the other hand, if it is determined in step S37 that the step is being overcome (YES in step S37), the process proceeds to step S70, and the required driving torque is calculated using the driving force map before the mode switching. In other words, during overcoming a step, the change in the driving force characteristics accompanying the mode switching can give the user a sense of incongruity, so the driving force characteristics are not changed according to the mode switching.

  As described above, in the eighth embodiment, the change in the driving force characteristic accompanying the mode switching can give the user a sense of incongruity during the step over the step. It is supposed to be implemented. Therefore, according to the eighth embodiment, special running in the CD mode can be realized, and the uncomfortable feeling given to the user in accordance with the realization can be reduced.

[Embodiment 9]
In the ninth embodiment, the driving force characteristic is not changed until it is determined that the accelerator opening has changed after the mode is switched. And if it determines with the accelerator opening having changed, the change of the driving force characteristic according to mode switching will be implemented. By changing the driving force characteristics in accordance with the operation for changing the accelerator opening after the mode switching, it is possible to reduce the uncomfortable feeling given to the user by the change of the driving force characteristics accompanying the mode switching.

  The overall configuration of the hybrid vehicle according to the ninth embodiment is the same as that of hybrid vehicle 100 shown in FIG.

  FIG. 14 is a flowchart for illustrating a procedure of required drive torque switching processing executed by ECU 26 in the ninth embodiment. Referring to FIG. 14, this flowchart includes step S38 instead of step S30 in the flowchart shown in FIG.

  That is, when it is determined in step S20 that the mode has been switched (YES in step S20), ECU 26 has an absolute value of the change amount of the accelerator opening after the mode switching is smaller than a predetermined value δ. It is determined whether or not (step S38). This determination process is for determining whether or not the accelerator opening change operation has been performed after the mode is switched, and when the accelerator opening increase from the accelerator opening at the time of the mode switching is greater than or equal to a predetermined value δ. (Step increase determination) or when the accelerator opening decrease amount from the accelerator opening at the time of mode switching is equal to or greater than a predetermined value δ (step return determination), it is determined that the accelerator opening change operation has been performed. The

  If it is determined in step S38 that the absolute value of the change amount of the accelerator opening after the mode switching is greater than or equal to predetermined value δ (NO in step S38), the process proceeds to step S40. . Step S40 and subsequent steps S50 and S60 are as described in FIG.

  On the other hand, when it is determined in step S38 that the absolute value of the change in accelerator opening after the mode is switched is smaller than predetermined value δ (YES in step S38), the process proceeds to step S70. The required driving torque is calculated using the driving force map before mode switching.

  As described above, in the ninth embodiment, the driving force characteristics are not changed according to the mode switching until it is determined that the accelerator opening is changed after the mode switching is performed. The driving force characteristics are changed along with the mode switching in accordance with the subsequent accelerator opening changing operation. Therefore, according to the ninth embodiment, a special running in the CD mode can be realized, and the uncomfortable feeling given to the user in accordance with the realization can be reduced.

[Embodiment 10]
In the tenth embodiment, when a predetermined condition is satisfied at the time of mode switching (in the case of YES in each of steps S30 to S38 in each of the above-described embodiments), the driving force characteristics are not changed according to the mode switching. In this case, if the required driving torque is smaller than a predetermined value, the driving force characteristic is changed according to the mode switching. Note that the predetermined value is a small value that does not give the user a sense of incongruity even when the vehicle driving torque changes suddenly as the driving force characteristics change. Since the driving force characteristic is changed in a state where the vehicle driving torque is small, it is possible to reduce a sense of discomfort that can be given to the user when the driving force characteristic is changed.

  The overall configuration of the hybrid vehicle according to the tenth embodiment is the same as that of hybrid vehicle 100 shown in FIG.

  FIG. 15 is a flowchart for illustrating a procedure of required drive torque switching processing executed by ECU 26 in the tenth embodiment. Referring to FIG. 15, this flowchart further includes step S100 in the flowchart shown in FIG.

  That is, when it is determined that the vehicle is traveling on a curve in step S30 (YES in step S30), ECU 26 determines whether the required drive torque (here, a calculated value immediately before mode switching) is smaller than a predetermined value δT. Is determined (step S100). The predetermined value δT is set to a small value that does not give the user a sense of incongruity even when the vehicle driving torque changes suddenly as the driving force characteristic changes.

  If it is determined in step S100 that the required drive torque is smaller than predetermined value δT (YES in step S100), the process proceeds to step S40. That is, when the required driving torque is smaller than the predetermined value δT, the driving force characteristic is changed along with the mode switching.

  On the other hand, if it is determined in step S100 that the required drive torque is equal to or greater than the predetermined value δT (NO in step S100), the process proceeds to step S70, and the required drive torque is calculated using the drive force map before mode switching. Is done. That is, when the required drive torque is large, the change of the driving force characteristic according to the mode switching is not performed.

  In the above flowchart, the description has been made based on the first embodiment, but in the other embodiments as well, although not particularly illustrated, the processing shown in step S100 can be added in the same manner.

  In the above description, when the required driving torque is smaller than the predetermined value δT, the driving force characteristic is changed along with the mode switching. However, when the required driving torque becomes zero, the driving force characteristic is changed. Changes may be made.

  As described above, according to the tenth embodiment, since the driving force characteristic is changed along with the mode switching while the vehicle driving torque is small, the driving force characteristic is changed along with the mode switching. The uncomfortable feeling that can be given to the user can be reduced.

[Embodiment 11]
When the driving mode (EV driving / HV driving) is switched according to the change in the driving force characteristics of the vehicle accompanying the mode switching, the frequency of starting / stopping the engine 2 increases, and the user may feel uncomfortable. is there. Therefore, in the hybrid vehicle according to the eleventh embodiment, when the driving mode is switched according to the change in the driving force characteristic accompanying the mode switching, the driving force characteristic changing accompanying the mode switching is changed. Not implemented.

  The overall configuration of the hybrid vehicle according to the eleventh embodiment is the same as that of hybrid vehicle 100 shown in FIG.

  FIG. 16 is a flowchart for illustrating a procedure of required drive torque switching processing executed by ECU 26 in the eleventh embodiment. Referring to FIG. 16, steps S10, S20, S80 are as described in FIG.

  If it is determined in step S20 that the mode has been switched (YES in step S20), ECU 26 proceeds to step S40 and determines whether or not the CD mode is selected. Steps S40, S50, and S60 are as described in FIG.

  When the required driving torque is calculated in step S50 or S60, the ECU 26 determines whether or not the driving mode (EV driving / HV driving) is switched by changing the driving force characteristics accompanying the mode switching ( Step S110). Specifically, the ECU 26 calculates vehicle power based on the required drive torque calculated in step S50 or S60. If the calculated vehicle power exceeds a predetermined engine start threshold, the ECU 26 determines that the travel mode (EV travel / HV travel) is switched.

  If it is determined in step S110 that the driving mode is to be switched (YES in step S110), ECU 26 uses the driving force map before the mode switching, based on the accelerator opening and the vehicle speed detected in step S10. To calculate the required drive torque (step S120). In other words, in this case, the change of the driving force characteristics accompanying the mode switching is not performed.

  On the other hand, when it is determined in step S110 that the driving mode is not switched (NO in step S110), ECU 26 skips step S120 and proceeds to step S90. That is, in this case, based on the required driving torque after mode switching calculated in step S50 or S60, the driving force characteristics are changed along with mode switching.

  As described above, in the eleventh embodiment, when the driving mode (EV traveling / HV traveling) is switched by changing the driving force characteristic accompanying the mode switching, the driving accompanying the mode switching is performed. Since the change in the force characteristic can give the user a sense of incongruity, the change in the driving force characteristic according to the mode switching is not performed. Therefore, according to the eleventh embodiment, a special running in the CD mode can be realized, and the uncomfortable feeling given to the user along with the realization can be reduced.

[Embodiment 12]
Similar to the tenth embodiment with respect to the first to ninth embodiments, this twelfth embodiment is required in the above-described eleventh embodiment when the change of the driving force characteristic according to the mode switching is not implemented. When the driving torque is smaller than a predetermined value, the driving force characteristic is changed according to the mode switching.

  The overall configuration of the hybrid vehicle according to the twelfth embodiment is the same as hybrid vehicle 100 shown in FIG.

  FIG. 17 is a flowchart for illustrating a procedure of required drive torque switching processing executed by ECU 26 in the twelfth embodiment. Referring to FIG. 17, this flowchart further includes step S115 in the flowchart shown in FIG.

  That is, when it is determined in step S110 that the travel mode is to be switched (YES in step S110), ECU 26 determines whether the required drive torque (here, a calculated value immediately before mode switching) is smaller than a predetermined value δT. It is determined whether or not (step S115). The predetermined value δT is set to a small value that does not give the user a sense of incongruity even when the vehicle driving torque changes suddenly as the driving force characteristic changes.

  If it is determined in step S115 that the required drive torque is smaller than predetermined value δT (YES in step S115), step S120 is skipped and the process proceeds to step S90. That is, when the required driving torque is smaller than the predetermined value δT, the required driving torque calculated in step S50 or S60 is adopted, and the driving force characteristic is changed along with the mode switching.

  On the other hand, when it is determined in step S115 that the required drive torque is equal to or greater than predetermined value δT (NO in step S115), the process proceeds to step S120. That is, when the required drive torque is large, the change of the driving force characteristic accompanying the mode switching is not performed.

  In the above description, when the required drive torque is smaller than the predetermined value δT, the driving force characteristic is changed according to the mode switching. However, when the required drive torque becomes zero, the driving force characteristic is changed. The force characteristics may be changed. Specifically, when the required drive torque is zero in step S115, step S120 may be skipped.

  As described above, according to the twelfth embodiment, since the driving force characteristic is changed along with the mode switching while the vehicle driving torque is small, the driving force characteristic is changed along with the mode switching. The uncomfortable feeling that can be given to the user can be reduced.

[Modification]
In each of the above embodiments, when a predetermined condition is satisfied (for example, in the case of the first embodiment, when it is determined that the vehicle is traveling in a curve by a predetermined curve traveling determination), the mode change is accompanied. The driving force characteristic is not changed. That is, although the mode is switched, the driving force characteristics are not changed along with the mode switching. On the other hand, mode switching itself may not be performed when a predetermined condition is satisfied.

  The overall configuration of the hybrid vehicle according to this modification is the same as that of hybrid vehicle 100 shown in FIG.

  FIG. 18 is a flowchart for explaining the procedure of the required drive torque switching process executed by the ECU 26 in the modified example. FIG. 18 representatively illustrates a modification corresponding to the first embodiment. The process shown in this flowchart is also called and executed from the main routine at predetermined time intervals or when a predetermined condition is satisfied.

  Referring to FIG. 18, ECU 26 receives detected values of the accelerator opening and the vehicle speed (step S10). Next, the ECU 26 determines whether or not there has been a request for mode switching (step S22). In this modification, only the mode switching is requested based on the SOC or according to the operation of the mode switch 28 (FIG. 1) by the user, and the mode switching is not immediately performed at this stage.

  If it is determined in step S22 that there has been a request for mode switching (YES in step S22), ECU 26 determines whether or not the vehicle is traveling on a curve based on a predetermined curve traveling determination (step S30). If it is determined that the vehicle is not traveling on a curve (NO in step S30), ECU 26 executes switching to the mode requested in step S22 (step S140).

  On the other hand, if it is determined in step S30 that the vehicle is traveling on a curve (YES in step S30), or if it is determined in step S22 that mode switching is not required (NO in step S22), ECU 26 The mode is maintained (step S142). That is, when it is determined that the vehicle is traveling on a curve, mode switching is not performed.

  Next, the ECU 26 determines whether or not the CD mode is selected (step S40). Note that it may be determined whether the CS mode is selected. If it is determined that the CD mode is selected (YES in step S40), the process proceeds to step S50, and if it is determined that the CS mode is selected (NO in step S40). The process proceeds to step S60. Steps S50 and S60 are as described in FIG.

Also by this modification, the same effects as those of the above embodiments can be obtained.
In each of the above embodiments, the control in hybrid vehicle 100 (FIG. 1) in which engine 2 and two motor generators 6 and 10 are connected by power split device 4 has been described. The hybrid vehicle to be used is not limited to such a configuration.

  For example, as shown in FIG. 19, the hybrid vehicle 100 </ b> A having a configuration in which the engine 2 and one motor generator 10 are connected in series via a clutch 15 will be described in the above embodiments. The applied control can be applied.

  Although not particularly shown, the present invention is also applicable to a so-called series type hybrid vehicle that uses the engine 2 only for driving the motor generator 6 and generates the driving force of the vehicle only by the motor generator 10. .

  Further, in each of the embodiments described above, hybrid vehicle 100 (100A) is a hybrid vehicle that can externally charge power storage device 16 with an external power source. The present invention is also applicable to a hybrid vehicle that does not have the section 24). The CD mode / CS mode is suitable for an externally chargeable hybrid vehicle, but is not necessarily limited to only an externally chargeable hybrid vehicle.

  In the above, engine 2 corresponds to an example of “internal combustion engine” in the present invention, and motor generator 10 corresponds to an example of “electric motor” in the present invention. ECU 26 corresponds to an embodiment of “control device” in the present invention, and power converter 23 and connecting portion 24 form an embodiment of “charging mechanism” in the present invention.

  The embodiments disclosed this time are also scheduled to be implemented in appropriate combinations. The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiment but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

  2 engine, 4 power split device, 6, 10 motor generator, 8 transmission gear, 12 drive shaft, 14 wheels, 15 clutch, 16 power storage device, 18, 20, 23 power converter, 22 drive device, 24 connection, 26 ECU, 28 mode switch, 100, 100A hybrid vehicle.

Claims (14)

An internal combustion engine;
A power storage device;
An electric motor that receives a supply of electric power from the power storage device and generates a driving force;
A CD (Charge Depleting) mode or a CS (Charge Sustaining) mode is selected, and in each of the CD mode and the CS mode, the internal combustion engine is stopped and the electric motor is driven in accordance with the driving situation. A control device for switching between a traveling mode of 1 and a second traveling mode for traveling by operating the internal combustion engine;
When the CD mode is selected, the power threshold value for switching from the first travel mode to the second travel mode is greater than the threshold value when the CS mode is selected. big,
When the predetermined condition is not satisfied, the control device changes the driving force characteristic of the vehicle according to the mode switching between the CD mode and the CS mode, and when the predetermined condition is satisfied, Change the driving force characteristics according to mode switching is not implemented,
When the predetermined condition is not satisfied, the control device drives the vehicle for the same vehicle speed and the same accelerator opening when the CD mode is selected than when the CS mode is selected. A hybrid vehicle in which the driving force characteristic is changed between the CD mode and the CS mode so that the torque is increased.   The control device further includes a vehicle speed at the same accelerator opening degree when the CD mode is selected in a range where the vehicle driving torque falls below a predetermined upper limit than when the CS mode is selected. 2. The hybrid vehicle according to claim 1, wherein the driving force characteristics of the vehicle are changed between the CD mode and the CS mode so that a decrease in the vehicle driving torque corresponding to the increase of the vehicle is reduced.   When the vehicle driving torque is smaller than a predetermined value when the driving force characteristic is not changed in accordance with the mode switching when the predetermined condition is satisfied, The hybrid vehicle according to claim 1, wherein the driving force characteristic is changed according to switching.   The hybrid vehicle according to any one of claims 1 to 3, wherein the predetermined condition includes that it is determined that the vehicle is traveling along a curve based on a predetermined curve traveling determination.   The predetermined condition includes switching between the first traveling mode and the second traveling mode by changing the driving force characteristic according to the mode switching. The hybrid vehicle of any one of Claims.   The hybrid vehicle according to any one of claims 1 to 3, wherein the predetermined condition includes selection of a reverse range. An input device for a user to select either the CD mode or the CS mode;
The hybrid vehicle according to any one of claims 1 to 3, wherein the predetermined condition includes that the mode switching is performed without operation of the input device.   The hybrid vehicle according to any one of claims 1 to 3, wherein the predetermined condition includes that the vehicle is determined to be in a stopped state on the slope by a predetermined slope balance determination.   The hybrid vehicle according to any one of claims 1 to 3, wherein the predetermined condition includes that the vehicle is determined to be traveling in a constant state by a predetermined steady traveling determination.   The hybrid vehicle according to any one of claims 1 to 3, wherein the predetermined condition includes that the vehicle is determined to travel in a coasting state by a predetermined coasting determination.   The hybrid vehicle according to claim 1, wherein the predetermined condition includes that the vehicle is accelerating.   The hybrid vehicle according to any one of claims 1 to 3, wherein the predetermined condition includes that the vehicle is determined to be over the step by a predetermined step overcoming determination.   The hybrid vehicle according to any one of claims 1 to 3, wherein the predetermined condition includes a change amount of an accelerator opening after the mode switching is smaller than a predetermined amount.   The hybrid vehicle according to claim 1, further comprising a charging mechanism for charging the power storage device using electric power from a power source external to the vehicle.

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