Driving force control device for hybrid vehicle

Abstract

The present application relates to a drive force control device for a hybrid vehicle. Provided is a drive force control device for a hybrid vehicle capable of suppressing a decrease in drive force during reverse travel while shortening the time from a shift request to a travel range to the start of travel. A drive force control device for a hybrid vehicle, in which torque transmitted from an engine to an output member via a transmission mechanism is opposed to reverse torque output from a second motor in a case where the engine is being driven, wherein in a case where a low mode is set in the transmission mechanism and a restriction condition for selecting a travel range to a reverse travel range is satisfied (Yes in steps S1 and S2), a start determination value for determining whether to start the engine is changed in such a manner that the engine is difficult to start as compared to a case where the restriction condition is not satisfied (step S3).

Description

Technical Field

[0001] The present invention relates to a drive force control device for a hybrid vehicle, comprising a differential mechanism connecting an engine and a first motor, and a second motor connected to a component on the output side of the differential mechanism. Background Technology

[0002] Patent Document 1 describes a hybrid vehicle equipped with a power distribution mechanism that distributes the engine's output torque to both the first motor side and the output side. In this manner, the power transmitted from the engine to the first motor is converted into electricity by the first motor and supplied to the second motor. Then, the vehicle travels by adding the torque transmitted from the engine to the drive wheels via the power distribution mechanism to the torque output from the second motor. The power distribution mechanism is configured to have two engagement mechanisms. By engaging one engagement mechanism, a low mode can be set where the proportion of torque transmitted to the output component of the power distribution mechanism is relatively large; by engaging the other engagement mechanism, a high mode can be set where the proportion of torque transmitted to the output component of the power distribution mechanism is relatively small compared to the low mode.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 6451524 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] In order to suppress the increase in engine speed caused by driving the engine, the hybrid vehicle described in Patent Document 1 outputs a reaction torque via a first motor. By outputting this reaction torque from the first motor, a portion of the engine torque is transmitted to the drive wheels. Since the direction of the torque when driving the engine is limited to one direction, the direction of the torque transmitted to the drive wheels is also limited to one direction. Therefore, the powertrain is configured such that the direction of the torque transmitted from the engine to the drive wheels via the power distribution mechanism becomes the drive torque for forward travel. Thus, in reverse travel, a second motor outputs drive torque for reverse travel; conversely, in the case of driving the engine, the drive torque for reverse travel decreases.

[0008] As described above, the proportion of torque transmitted from the engine to the drive wheels via the power distribution mechanism is smaller in the high mode than in the low mode. Therefore, in order to suppress the reduction of drive torque used for reverse driving, it is preferable to set the high mode. However, when driving forward at low vehicle speeds and requiring high driving force, there is a situation where the torque is insufficient due to the drive torque of the second motor alone. In addition, in order to reduce the energy loss of the engine and each motor, it is preferable to set the low mode, which transmits a large amount of torque from the engine via the power distribution mechanism.

[0009] Therefore, if the driving mode is switched based on the driving gear selected when parking, the engagement mechanism is switched after the gear lever is operated to change the driving gear. Thus, the time taken from operating the gear lever to starting to drive may cause discomfort to the driver.

[0010] The present invention was made in view of the above-mentioned technical problems, and its purpose is to provide a drive force control device for a hybrid vehicle that can suppress the reduction of drive force when driving backward and shorten the time from the request to shift to drive gear to the start of driving.

[0011] Solution for solving the problem

[0012] To achieve the above objectives, the present invention provides a drive force control device for a hybrid vehicle, characterized by comprising: an engine; a first rotary motor; a transmission mechanism configured such that: a first rotary member connected to the engine, a second rotary member connected to the first rotary motor, and a third rotary member connected to an output member are connected in a differentially rotatable manner, and a reaction torque is output from the first rotary motor to transmit torque from the engine to the output member, and the mechanism is capable of setting a low mode in which the proportion of torque transmitted to the output member from the torque output from the engine is a first predetermined value and a high mode in which the proportion is a second predetermined value smaller than the first predetermined value; a second rotary motor connected to the output member in a manner capable of transmitting torque; and an energy storage device. The device is electrically connected to the first rotary motor and the second rotary motor. The drive force control device of the hybrid vehicle is configured to perform reverse driving by outputting reverse torque from the second rotary motor. When the engine is driving, the torque transmitted from the engine to the output member via the transmission mechanism counteracts the reverse torque. The drive force control device of the hybrid vehicle includes a controller that controls the engine, the first rotary motor, and the second rotary motor. When the restriction condition of the transmission mechanism setting the low mode and the driving gear selecting the reverse driving gear is met, the controller changes the starting determination value used to determine starting the engine in a manner that makes it difficult to start the engine compared to the case where the restriction condition is not met.

[0013] In this invention, the starting determination value may include an engine starting threshold determined based on the required driving force or required driving power of the hybrid vehicle. The controller is configured to start the engine when the required driving force or the required driving power is above the engine starting threshold. When the limiting condition is met, the controller increases the engine starting threshold compared to when the limiting condition is not met.

[0014] In this invention, the first rotary motor may be configured to convert the power transmitted from the engine into electricity and supply the converted electricity to the energy storage device. The start-up determination value includes a charging start threshold based on the remaining charge amount of the energy storage device to start the engine. The controller is configured to start the engine when the remaining charge amount is below the charging start threshold. When the limiting condition is met, the controller lowers the charging start threshold compared to when the limiting condition is not met.

[0015] In this invention, the controller may be configured to determine the output power of the engine when the engine is driven as the total power obtained by combining the driving power used to drive the hybrid vehicle and the charging power used to charge the energy storage device. When the transmission mechanism is set to the low mode and the driving gear is selected to be reverse driving gear, the controller reduces the output torque of the engine compared to the case where the limiting condition is not met.

[0016] Furthermore, the present invention relates to a drive force control device for a hybrid vehicle, characterized by comprising: an engine; a first rotary motor; a transmission mechanism configured such that: a first rotary component connected to the engine, a second rotary component connected to the first rotary motor, and a third rotary component connected to an output member are connected in a differentially rotatable manner, and a reaction torque is output from the first rotary motor to transmit torque from the engine to the output member, and the mechanism is capable of setting a low mode in which the proportion of torque transmitted to the output member from the torque output from the engine is a first predetermined value and a high mode in which the proportion is a second predetermined value smaller than the first predetermined value; a second rotary motor connected to the output member in a manner capable of transmitting torque; and an energy storage device electrically connected to the first rotary motor and the second rotary motor, wherein the hybrid vehicle... The drive force control device is configured to perform reverse driving by outputting reverse torque from the second rotary motor. When the engine is driving, the torque transmitted from the engine to the output member via the transmission mechanism counteracts the reverse torque. The drive force control device of the hybrid vehicle includes a controller that controls the engine, the first rotary motor, and the second rotary motor. The controller is configured to determine the output power of the engine when the engine is driving as a total power obtained by combining the driving power used to drive the hybrid vehicle and the charging power used to charge the energy storage device. When the restriction condition that the transmission mechanism is set to the low mode and the driving gear is selected to be reverse driving gear is met, the controller reduces the output torque of the engine compared to the case where the restriction condition is not met.

[0017] In this invention, when the limiting condition is met, the controller maintains the engine's output power at the same level as when the limiting condition is not met, while increasing the engine's speed, thereby reducing the engine's output torque.

[0018] In this invention, the controller may set the charging power to be lower than the value when the limiting condition is not met, thereby reducing the output power and torque of the engine.

[0019] In this invention, the controller may be configured to also control the transmission mechanism, such that, after a predetermined period has elapsed since the hybrid vehicle began reversing, the controller switches the transmission mechanism from the low mode to the high mode and restores the changed start determination value to the start determination value under the condition that the limiting condition is not met.

[0020] In this invention, the controller may be configured to also control the transmission mechanism, such that, after a predetermined period has elapsed since the hybrid vehicle began reversing, the controller switches the transmission mechanism from the low mode to the high mode and restores the reduced engine output torque to the engine output torque under conditions where the limiting condition is not met.

[0021] In this invention, the controller may determine whether the hybrid vehicle is reversing on a high-load driving road where the required driving force is greater than the predetermined driving force. When driving on such a high-load road, the controller changes the starting determination value.

[0022] In this invention, the controller may determine whether the hybrid vehicle is reversing on a high-load driving road where the required driving force is greater than the predetermined driving force. When driving on such a high-load driving road, the controller reduces the output torque of the engine.

[0023] In this invention, the controller may determine whether the hybrid vehicle is approaching a high-load driving road where the required driving force for reversing is greater than a predetermined driving force. If the vehicle is approaching the high-load driving road, the controller increases the charging power of the energy storage device compared to the case where the vehicle is not approaching the high-load driving road.

[0024] Furthermore, the present invention relates to a drive force control device for a hybrid vehicle, characterized in that it comprises: an engine; a first rotary motor; a transmission mechanism configured such that: a first rotary component connected to the engine, a second rotary component connected to the first rotary motor, and a third rotary component connected to an output member are connected in a differentially rotatable manner, and a reaction torque is output from the first rotary motor to transmit torque from the engine to the output member, and the mechanism is capable of setting a low mode in which the proportion of torque transmitted to the output member from the torque output from the engine is a first predetermined value and a high mode in which the proportion is a second predetermined value smaller than the first predetermined value; a second rotary motor connected to the output member in a manner capable of transmitting torque; and an energy storage device connected to the first rotary motor. The first rotary motor and the second rotary motor are electrically connected. The drive force control device of the hybrid vehicle is configured to perform reverse driving by outputting reverse torque from the second rotary motor. When the engine is driving, the torque transmitted from the engine to the output member via the transmission mechanism counteracts the reverse torque. The drive force control device of the hybrid vehicle includes a controller that controls the engine, the first rotary motor, and the second rotary motor. The controller determines whether the hybrid vehicle is approaching a high-load driving road where the required drive force for reverse driving is greater than a predetermined drive force. If the vehicle is approaching the high-load driving road, the controller increases the charging power of the energy storage device compared to the case where the vehicle is not approaching the high-load driving road.

[0025] In this invention, when the engine stops near the high-load driving road, the controller can start the engine to increase the charging power of the energy storage device.

[0026] The effects of the invention

[0027] The transmission mechanism in this invention is configured to transmit the torque output from the engine to the output member by outputting a reaction torque from the first rotary motor, which counteracts the reverse torque. Furthermore, the torque transmitted to the output member is configured to be greater in the low mode than in the high mode. In hybrid vehicles equipped with such a transmission mechanism, during reverse driving, the torque transmitted from the engine to the output member functions to reduce the driving force during reverse driving. Therefore, this invention, when the transmission mechanism is set to low mode and the reverse driving gear is selected, modifies the starting determination threshold used to determine engine start in a way that makes starting the engine difficult. That is, by changing the starting determination threshold, the area of ​​travel using the second rotary motor is expanded compared to the case where the starting determination threshold is not changed. In other words, it is possible to drive using only the driving force output by the second rotary motor, which is greater than when the starting determination threshold is not changed. As a result, when the engine is stopped and the low mode is set, reverse driving can be performed using only the power of the second rotary motor, shortening the time from selecting the reverse driving gear to starting reverse driving.

[0028] Furthermore, when the transmission mechanism is set to low mode and reverse gear is selected, reducing the engine's output torque suppresses the increase in torque that counteracts the torque used for reverse travel. Therefore, reverse travel can be performed simply by keeping the transmission mechanism in low mode, shortening the time from the gear shift request to the start of travel. Additionally, even when reverse travel is performed with the engine driven in low mode, reducing the engine's output torque suppresses the decrease in driving force during reverse travel.

[0029] Furthermore, by increasing the charging demand as one approaches a slope to accelerate the charging of the battery storage device, a higher State of Charge (SOC) can be maintained at the moment reverse travel begins on an uphill slope. Therefore, the electrical power output from the battery storage device to the second rotary motor can be increased. In other words, high driving force can be obtained when reversing using only the second rotary motor as the driving force source, and its travel time (or distance) can be extended. Therefore, reverse travel on uphill slopes is possible even with the engine stopped. In other words, reverse travel can be performed without changing the mode set by the transmission mechanism, thus shortening the time from shifting from driving gear to reverse gear to the start of reverse travel. Attached Figure Description

[0030] Figure 1 This is a frame diagram illustrating an example of a hybrid vehicle of the present invention.

[0031] Figure 2It is a chart that summarizes and shows the engagement and disengagement status of the clutch and brake mechanisms, the operating status of the motor, and whether the engine is driving in each driving mode.

[0032] Figure 3 It is a line graph used to illustrate the action state in HV-Hi mode.

[0033] Figure 4 It is a line graph used to illustrate the action state in HV-Lo mode.

[0034] Figure 5 It is a line diagram used to illustrate the action state in the direct connection mode.

[0035] Figure 6 It is a line graph used to illustrate the action state in EV-Lo mode.

[0036] Figure 7 It is a line graph used to illustrate the action status in EV-Hi mode.

[0037] Figure 8 It is a line graph used to illustrate the action state in a single mode.

[0038] Figure 9 This is a flowchart illustrating a control example that increases the engine starting threshold when the reverse gear is selected and the Lo clutch mechanism is engaged.

[0039] Figure 10 It means execution Figure 9 The timing diagram shows the changes in driving mode and engine start threshold under the control example shown.

[0040] Figure 11 This is a flowchart illustrating a control example that lowers the charging start threshold when the reverse driving gear is selected and the Lo clutch mechanism is engaged.

[0041] Figure 12 It means that it has been executed. Figure 11 The timing diagram shows the changes in driving mode and charging start threshold under the control example shown.

[0042] Figure 13 This is a flowchart illustrating a control example that increases engine speed when reversing.

[0043] Figure 14 It means that it has been executed. Figure 13 The timing diagram shows the driving mode, the indicator that enables the engine to operate, the engine speed, and the changes in engine torque under the control example shown.

[0044] Figure 15This is a flowchart illustrating a control example that reduces the charging requirement when reversing.

[0045] Figure 16 It means that it has been executed. Figure 15 The timing diagram shows the changes in driving mode, engine start signal, charging demand, engine speed, and engine torque under the control example shown.

[0046] Figure 17 This is a flowchart illustrating a control example for restoring the engine starting threshold.

[0047] Figure 18 It means that it has been executed. Figure 17 The timing diagram shows the changes in driving mode and engine start threshold under the control example shown.

[0048] Figure 19 This is a flowchart illustrating a control example for resuming the charging start threshold.

[0049] Figure 20 It means that it has been executed. Figure 19 The timing diagram shows the changes in driving mode and charging start threshold under the control example shown.

[0050] Figure 21 This is a flowchart illustrating a control example for restoring engine speed.

[0051] Figure 22 It means that it has been executed. Figure 21 The timing diagram shows the driving mode, the indicator that enables the engine to operate, the engine speed, and the changes in engine torque under the control example shown.

[0052] Figure 23 This is a flowchart illustrating a control example for restoring the required charging amount.

[0053] Figure 24 It means that it has been executed. Figure 23 The timing diagram shows the changes in driving mode, engine start signal, charging demand, engine speed, and engine torque under the control example shown.

[0054] Figure 25 It is performed when reversing, which requires high driving force. Figure 9 The flowchart for the control example shown.

[0055] Figure 26 This is a flowchart illustrating a control example for promoting the charging of an energy storage device when approaching a slope.

[0056] Figure 27 It means that it has been executed. Figure 26The timing diagram shows the changes in SOC determination flag, ramp determination flag, engine start flag, charge demand, engine speed, and engine torque under the control example shown.

[0057] Explanation of reference numerals in the attached figures

[0058] 1R, 1L, front wheels; 2, drive unit; 3, engine; 4, 5, motor; 6, power distribution mechanism; 30, energy storage device; 31, electronic control unit (ECU); C_Lo, Lo clutch mechanism; C_Hi, Hi clutch mechanism. Detailed Implementation

[0059] The drive force control device in the embodiments of the present invention is a drive force control device for a hybrid vehicle having a power distribution mechanism that distributes the torque output from the engine to the first motor side and the drive wheel side, and can set a low mode in which the torque output from the engine is relatively large to the drive wheel side and a high mode in which the torque transmitted to the drive wheel side is relatively small.

[0060] Reference Figure 1 This illustrates an example of such a hybrid vehicle. Figure 1 This refers to the drive unit 2 used to drive the front wheels 1R and 1L. The drive unit 2 is a so-called dual-motor type drive unit, equipped with an engine 3 and two motors 4 and 5 as driving power sources. It is configured such that the first motor 4 is a motor with power generation function (i.e., an electric generator: MG1), which controls the speed of the engine 3, and uses the electricity generated by the first motor 4 to drive the second motor 5, adding the torque output by the second motor 5 to the torque used for driving. It should be noted that the second motor 5 can be composed of a motor with power generation function (i.e., an electric generator: MG2). The aforementioned first motor 4 corresponds to the "first rotary motor" in the embodiments of the present invention, and the second motor 5 corresponds to the "second rotary motor" in the embodiments of the present invention.

[0061] The engine 3 is connected to a power distribution mechanism 6, which is equivalent to the "transmission mechanism" in the embodiments of the present invention. The power distribution mechanism 6 consists of a distribution section 7, which mainly distributes the torque output from the engine 3 to the first motor 4 and the output side, and a transmission section 8, which mainly changes the distribution rate of the torque.

[0062] The distribution unit 7 can be a structure that uses three rotating parts for differential action, and a planetary gear mechanism can be used. Figure 1 In the example shown, it is composed of a planetary gear mechanism of the single pinion type. Figure 1The distribution unit 7 shown comprises a sun gear 9, a ring gear 10 arranged concentrically on a circle relative to the sun gear 9 as an internal gear, a pinion 11 disposed between the sun gear 9 and the ring gear 10 and meshing with the sun gear 9 and the ring gear 10, and a planet carrier 12 that holds the pinion 11 so that it can rotate and revolve. The sun gear 9 mainly functions as a reaction force component, the ring gear 10 mainly functions as an output component, and the planet carrier 12 mainly functions as an input component.

[0063] The power output from engine 3 is configured to be input to the planetary carrier 12. Specifically, the input shaft 14 of the power distribution mechanism 6 is connected to the output shaft 13 of engine 3, and this input shaft 14 is connected to the planetary carrier 12. The planetary carrier 12 corresponds to the "first rotating member" in the embodiment of the present invention. It should be noted that, instead of directly connecting the planetary carrier 12 and the input shaft 14, the planetary carrier 12 and the input shaft 14 can be connected via a transmission mechanism such as a gear mechanism. In addition, a vibration damping mechanism, torque converter, or other mechanism can be arranged between the output shaft 13 and the input shaft 14.

[0064] The aforementioned sun gear 9 corresponds to the "second rotating component" in the embodiment of the present invention, and the sun gear 9 is connected to the first motor 4. Figure 1 In the example shown, the distribution unit 7 and the first motor 4 are arranged on the same axis as the rotation center axis of the engine 3, and the first motor 4 is arranged on the opposite side of the engine 3, separated by the distribution unit 7. Between the distribution unit 7 and the engine 3, a transmission unit 8 is arranged along the same axis as the distribution unit 7 and the engine 3.

[0065] The transmission unit 8 is composed of a single-pinion-type planetary gear mechanism, including a sun gear 15, a ring gear 16 arranged concentrically on the sun gear 15 as an internal gear, a pinion 17 disposed between and meshing with the sun gear 15 and the ring gear 16, and a planet carrier 18 that holds the pinion 17 so that it can rotate and revolve. It is a differential mechanism that performs differential action through these three rotating components: the sun gear 15, the ring gear 16, and the planet carrier 18. The sun gear 15 in the transmission unit 8 is connected to the ring gear 10 in the distribution unit 7. Furthermore, the ring gear 16 in the transmission unit 8 is connected to an output gear 19. The ring gear 16 corresponds to the "third rotating member" in the embodiment of the present invention, and the output gear 19 corresponds to the "output member" in the embodiment of the present invention.

[0066] A Lo clutch mechanism C_Lo is provided in such a manner that the distribution section 7 and the transmission section 8 constitute a compound planetary gear mechanism. The Lo clutch mechanism C_Lo is configured to selectively connect the planet carrier 18 in the transmission section 8 to the planet carrier 12 in the distribution section 7. This Lo clutch mechanism C_Lo can be a friction clutch mechanism such as a wet multi-plate clutch, or a meshing clutch mechanism such as a dog-tooth clutch. By engaging the Lo clutch mechanism C_Lo, the planet carrier 12 in the distribution section 7 and the planet carrier 18 in the transmission section 8 are connected, forming a compound planetary gear mechanism in which the planet carrier 12 in the distribution section 7 and the planet carrier 18 in the transmission section 8 become input components, the sun gear 9 in the distribution section 7 becomes a reaction force component, and the ring gear 16 in the transmission section 8 becomes an output component.

[0067] Furthermore, a Hi clutch mechanism C_Hi is provided for integrating the transmission unit 8. This Hi clutch mechanism C_Hi connects at least two rotating components in the transmission unit 8, such as connecting the planet carrier 18 to the ring gear 16 or the sun gear 15, or connecting the sun gear 15 to the ring gear 16, and can be constructed from a friction-type or engagement-type clutch mechanism. Figure 1 In the example shown, the Hi clutch mechanism C_Hi is configured to connect the planetary carrier 18 and the ring gear 16 in the transmission section 8.

[0068] Furthermore, the Lo clutch mechanism C_Lo and the Hi clutch mechanism C_Hi are arranged on the same axis as the engine 3, the distribution unit 7, and the transmission unit 8, and are located on the opposite side from the distribution unit 7, separated by the transmission unit 8. It should be noted that... Figure 1 As shown, the clutch mechanisms C_Lo and C_Hi can also be configured to be arranged along the radial direction on the inner and outer circumferential sides, or they can be arranged along the axial direction. Figure 1 When arranged radially as shown, the shaft length of the drive unit 2 as a whole can be shortened. Furthermore, when arranged axially, the constraints on the outer diameters of each clutch mechanism C_Lo and C_Hi are reduced, thus reducing the number of friction plates when using a friction-type clutch mechanism.

[0069] A secondary shaft 20 is arranged parallel to the rotational center axis of the aforementioned engine 3, distribution unit 7, or transmission unit 8. A driven gear 21, which meshes with the output gear 19, is mounted on this secondary shaft 20. In addition, a drive gear 22 is mounted on the secondary shaft 20, which meshes with the ring gear 24 in the differential gear unit 23, which serves as the final reducer.

[0070] Furthermore, the drive gear 26 mounted on the rotor shaft 25 of the second motor 5 meshes with the driven gear 21. Therefore, the power or torque output from the output gear 19 is added to the power or torque output from the second motor 5 at a portion of the driven gear 21. This combined power or torque is then output from the differential gear unit 23 to the left and right drive shafts 27, and this power or torque is transmitted to the front wheels 1R and 1L.

[0071] It should be noted that, Figure 1 The drive unit 2 shown is equipped with a friction-type or engagement-type brake mechanism B. This friction-type or engagement-type brake mechanism B is configured to selectively fix the output shaft 13 or the input shaft 14 so that the drive torque output from the first motor 4 can be transmitted to the front wheels 1R and 1L. That is, by fixing the output shaft 13 or the input shaft 14 through engaging the brake mechanism B, the planet carrier 12 in the distribution section 7 and the planet carrier 18 in the transmission section 8 can function as reaction force members, and the sun gear 9 in the distribution section 7 can function as an input member. This brake mechanism B only needs to generate a reaction torque when the first motor 4 outputs drive torque, and is not limited to a structure that completely fixes the output shaft 13 or the input shaft 14, as long as the required reaction torque can be applied to the output shaft 13 or the input shaft 14. Alternatively, a one-way clutch that prevents the output shaft 13 and the input shaft 14 from rotating in the opposite direction to the direction of rotation when the engine 3 is driven can also be provided as the brake mechanism B.

[0072] The first motor 4 is connected to a first power control device 28 equipped with an inverter, converter, etc., and the second motor 5 is connected to a second power control device 29 equipped with an inverter, converter, etc. These power control devices 28 and 29 are connected to an energy storage device 30 composed of lithium-ion batteries, capacitors, etc. In other words, each motor 4 and 5 is electrically connected in a manner that allows for power exchange with the energy storage device 30. Furthermore, the first power control device 28 and the second power control device 29 are configured to supply power to each other. Specifically, when the first motor 4 functions as a generator with output reaction torque, the power generated by the first motor 4 can be supplied to the second motor 5 without passing through the energy storage device 30.

[0073] An electronic control unit (ECU) 31 is provided for controlling the inverters, converters, engine 3, clutch mechanisms C_Lo, C_Hi, and brake mechanism B in the aforementioned power control devices 28 and 29. This ECU 31 is equivalent to a "controller" in this embodiment of the invention, and is primarily composed of a microcomputer. Based on input signals and pre-stored mappings or formulas, it outputs signals for controlling the power control devices 28 and 29, engine 3, clutch mechanisms C_Lo, C_Hi, and brake mechanism B. Examples of signals input to the ECU 31 include those from sensors that detect the operation of the accelerator pedal and brake pedal, sensors that detect vehicle speed, sensors that detect the remaining charge (SOC) of the battery storage device 30, the temperature of the battery storage device 30, the temperature and rotational speed of each motor 4 and 5, sensors that detect (receive) external conditions via radar, navigation systems, GPS, etc.

[0074] The aforementioned drive unit 2 can be set to an HV driving mode, in which the vehicle travels by outputting drive torque from the engine 3, and an EV driving mode, in which the vehicle travels by outputting drive torque from the first motor 4 and the second motor 5 instead of the engine 3. Furthermore, the HV driving mode can be set to an HV-Lo mode, in which the proportion (distribution rate) of the torque output from the engine 3 is large, an HV-Hi mode, in which the distribution rate of this torque is small, and a direct connection mode, in which the torque output from the engine 3 is directly transmitted to the output gear 19.

[0075] Specifically, when the torque output from engine 3 is set to Te, in HV-Lo mode, the torque transmitted to output gear 19 is (1 / (1-ρ1·ρ2))Te, in HV-Hi mode it is (1 / (1+ρ1))Te, and in direct-drive mode it is Te. Here, ρ1 is the ratio of the number of teeth of ring gear 10 to the number of teeth of sun gear 9, ρ2 is the ratio of the number of teeth of ring gear 16 to the number of teeth of sun gear 15, and ρ1 and ρ2 are values ​​smaller than "1". Therefore, when HV-Lo mode is set, the torque mechanically transmitted to output gear 19 via power distribution mechanism 6 is greater than when HV-Hi mode is set. Therefore, it is configured to set HV-Lo mode at the moment of starting forward travel. It should be noted that HV-Lo mode is equivalent to "low mode" in the embodiment of the present invention, and the ratio of torque transmitted to output gear 19 (1 / (1-ρ1·ρ2)) when the above-mentioned HV-Lo mode is set is equivalent to "first predetermined value" in the embodiment of the present invention. Similarly, the HV-Hi mode is equivalent to the "high mode" in the embodiment of the present invention, and the ratio of the torque transmitted to the output gear 19 (1 / (1+ρ1)) when the above-mentioned HV-Hi mode is set is equivalent to the "second predetermined value" in the embodiment of the present invention.

[0076] Furthermore, the aforementioned HV-Lo and HV-Hi modes are configured as continuously variable transmission modes that can control the speed of the engine 3 by controlling the speed of the first motor 4. In contrast, for the direct-connect mode, the speeds of the engine 3 and the output gear 19 are the same.

[0077] Furthermore, the EV driving mode can be set to a dual mode where drive torque is output from both motor 4 and motor 5, and a single mode where drive torque is output only from motor 5, not motor 4. Furthermore, the dual mode can be set to an EV-Lo mode with a higher amplification rate of the torque output from motor 4, and an EV-Hi mode with a lower amplification rate of the torque output from motor 4. It should be noted that in single mode, the vehicle can operate with drive torque output only from motor 5 when the Lo clutch mechanism C_Lo is engaged, with drive torque output only from motor 5 when the Hi clutch mechanism C_Hi is engaged, or with drive torque output only from motor 5 when all clutch mechanisms C_Lo and C_Hi are released.

[0078] These driving modes are set by controlling the Lo clutch mechanism C_Lo, the Hi clutch mechanism C_Hi, the brake mechanism B, and the engine 3, and each of the motors 4 and 5. Figure 2 The diagram illustrates these driving modes, the engagement and disengagement states of the Lo clutch mechanism C_Lo, Hi clutch mechanism C_Hi, and brake mechanism B in each driving mode, the operating states of the first motor 4 and the second motor 5, and an example of whether or not there is a drive torque output from the engine 3. In the diagram, the symbol "●" indicates engagement, "-" indicates disengagement, "G" indicates primary operation as a generator, "M" indicates primary operation as a motor, an empty column indicates that the engine 4 and second motor 5 are not functioning as a motor or generator, or that they are not involved in driving. "ON" indicates that the engine 3 outputs drive torque, i.e., it drives the engine 3 as an energy source to power the hybrid vehicle, and "OFF" indicates that the engine 3 does not output drive torque, i.e., it does not drive the engine 3 as an energy source to power the hybrid vehicle.

[0079] The operation in the HV-Hi and HV-Lo modes described above is illustrated using nomograms. A nomogram is a diagram in which straight lines representing the rotating components in the power distribution mechanism 6 are drawn parallel to each other, spaced apart by the gear ratio. The distance from a baseline orthogonal to these lines is used to represent the rotational speed of each rotating component. Arrows are used on the straight lines representing each rotating component to indicate the direction of the torque, and the length of the arrow indicates its magnitude.

[0080] like Figure 3 and Figure 4 As shown, in HV-Hi and HV-Lo modes, drive torque is output from engine 3, engaging either the Lo clutch mechanism C_Lo or the Hi clutch mechanism C_Hi, and reaction torque is output from the first motor 4. In this case, the speed of the first motor 4 can be controlled in an optimal manner, taking into account the fuel economy of engine 3, the drive efficiency of the first motor 4, and the overall efficiency of the drive unit 2 (the value obtained by dividing the energy consumed by the energy of the front wheels 1R and 1L). The speed of the first motor 4 can be continuously varied, and the engine speed is determined based on the speed of the first motor 4 and the vehicle speed. Therefore, the power distribution mechanism 6 functions as a continuously variable transmission.

[0081] By outputting reaction torque from the first motor 4 as described above, when the first motor 4 functions as a generator, a portion of the power of the engine 3 is converted into electrical energy by the first motor 4. Then, the power obtained by subtracting the amount of power converted into electrical energy by the first motor 4 from the power of the engine 3 is transmitted to the ring gear 16 in the transmission unit 8. The ratio of the torque transmitted to the first motor 4 to the torque transmitted to the ring gear 16 (or output gear 19) differs between HV-Lo and HV-Hi modes. That is, when the HV-Lo mode is set as described above, the torque transmitted to the ring gear 16 is greater than when the HV-Hi mode is set; conversely, when the HV-Lo mode is set, the reaction torque output from the first motor 4 should be smaller than when the HV-Hi mode is set.

[0082] Furthermore, the electricity generated by the first motor 4 is supplied to the second motor 5 and the energy storage device 30. Specifically, when the first motor 4 generates more than or equal to the output (power) required by the second motor 5, the remaining electricity is supplied to the energy storage device 30 in addition to the second motor 5. On the other hand, when the electricity generated by the first motor 4 is less than or equal to the output (power) required by the second motor 5, electricity is supplied to the second motor 5 from the energy storage device 30 in addition to the first motor 4.

[0083] In direct connection mode, the clutches C_Lo and C_Hi engage, such as... Figure 5As shown, all rotating components in the power distribution mechanism 6 rotate at the same speed. That is, all the power of the engine 3 can be output from the power distribution mechanism 6. In this case, a portion of the power of the engine 3 is not converted into electrical energy by the first motor 4 and the second motor 5. Therefore, there is no loss, mainly due to resistance generated during conversion into electrical energy, thus improving the power transmission efficiency. It should be noted that even in the direct connection mode, the first motor 4 and the second motor 5 can function as generators to charge the energy storage device 30.

[0084] With the HV driving mode set as described above, the total power output from engine 3 is configured to be the sum of the driving power required to drive the hybrid vehicle and the charging power required to charge the battery storage device 30. This is also true during reverse driving, as described later. It should be noted that, with the output (power) of engine 3 thus determined, the speed of the first motor 4 is controlled to ensure that the engine 3 operates at a fuel-efficient speed.

[0085] It should be noted that, as Figure 6 and Figure 7 As shown, in EV-Lo and EV-Hi modes, the brake mechanism B engages, and drive torque is output from each of the motors 4 and 5 for propulsion. Figure 6 and Figure 7 As shown, the ratio of the rotational speed of the first motor 4 to the rotational speed of the gear ring 16 in the transmission unit 8 is greater in EV-Lo mode than in EV-Hi mode. That is, the reduction ratio in EV-Lo mode is greater than that in EV-Hi mode. Therefore, by setting the EV-Lo mode, a larger driving force can be obtained. Furthermore, in single mode, such as... Figure 8 As shown, drive torque is output only from the second motor 5, and the clutch mechanisms C_Lo and C_Hi are released, thereby stopping the rotating parts of the distribution unit 7. Therefore, power loss caused by driving the engine 3 and the first motor 4 to rotate can be reduced.

[0086] like Figure 3 and Figure 4 As shown, when torque is output from engine 3, a reaction torque is output from first motor 4 to suppress excessive increase in engine speed. As a result, a portion of the torque output from engine 3 is transmitted to the front wheels 1R and 1L via power distribution mechanism 6 in the direction that propels the hybrid vehicle forward. Therefore, in reverse driving, it is preferable to set a single mode and use the power of second motor 5 for driving.

[0087] On the other hand, when the output power required by the second motor 5 for reverse driving is relatively large, and the power supplied by the energy storage device 30 alone cannot meet the required output power of the second motor 5, power is supplied from the first motor 4 to the second motor 5 in addition to the energy storage device 30. Specifically, the Lo clutch mechanism C_Lo or the Hi clutch mechanism C_Hi is engaged, and the engine 3 is driven. At least a portion of the power output from the engine 3 by the first motor 4 is converted into electricity, and this converted electricity is supplied to the second motor 5. That is, the output power of the engine 3 is determined so that the first motor 4 provides power that is insufficient in the energy storage device 30. In this case, the torque transmitted from the engine 3 via the power distribution mechanism 6 acts in opposition to the torque output from the second motor 5 for reverse driving (reverse torque). Therefore, when reverse driving requires a relatively large driving force, it is preferable to set the HV-Hi mode, where the torque transmitted via the power distribution mechanism 6 is relatively small.

[0088] When the hybrid vehicle begins to move forward as described above, the HV-Lo mode is set. Therefore, the HV-Lo mode is typically set when the hybrid vehicle is stopped. Thus, when reversing from forward motion to a stop, and more specifically, when reversing on high-load driving roads requiring significant driving force, such as uphill roads, it is preferable to switch the driving mode from HV-Lo mode to HV-Hi mode to reduce the torque opposing the reversing torque of the second motor 5. In this case, the driving mode is switched to HV-Hi mode after the driver shifts the gear lever from the drive position to the reverse position. Therefore, a driving mode switch is required from the gear shift operation until the hybrid vehicle begins to reverse, thus taking time. Furthermore, when the Lo clutch mechanism C_Lo and the Hi clutch mechanism C_Hi are engaging engagement mechanisms, a clicking sound, such as canine teeth contacting each other, may occur when the Hi clutch mechanism C_Hi is engaged to switch to HV-Hi mode. In particular, the Hi clutch mechanism C_Hi needs to be engaged when parking, so if a locking sound is produced, the driver may experience discomfort (unpleasant feeling).

[0089] Therefore, the drive force control device in the embodiments of the present invention is configured such that, by changing the determination threshold for starting the engine 3 from a predetermined normal value (i.e., a determination threshold where the conditions described in the following control examples are not met), in a manner where the engine 3 is difficult to start, reverse driving can be performed while the engine 3 is stopped. In other words, it is configured to expand the area where driving is possible solely by the power of the second motor 5. That is, by configuring the clutch mechanism that engages the engine 3 without starting it or without shifting gears, the time from the request to shift gears to the start of driving can be shortened. Figure 9 The diagram shows a flowchart illustrating an example of this control. Figure 9 In the example shown, the first step is to determine whether the driving gear is reverse (R gear) (step S1). This step S1 can be determined based on whether the gear lever has been moved to the reverse position.

[0090] If a negative judgment is made in step S1 because the driving gear is not a reverse driving gear, the routine is temporarily terminated. Conversely, if a positive judgment is made in step S1 because the driving gear is a reverse driving gear, it is determined whether only the Lo clutch mechanism C_Lo is engaged (step S2). In other words, it is determined whether the driving mode when the engine 3 is driven is HV-Lo mode. This step S2 can be determined, for example, based on whether a signal is output to engage the actuator for operating the Lo clutch mechanism C_Lo and a signal is output to release the actuator for operating the Hi clutch mechanism C_Hi, and whether the operating positions of these actuators are in a position that only engages the Lo clutch mechanism C_Lo. The conditions of the above steps S1 and S2 are equivalent to the "limiting conditions" in the embodiments of the present invention.

[0091] If the Lo clutch mechanism C_Lo is not engaged, and a negative judgment is made in step S2 because the Hi clutch mechanism C_Hi is also engaged in addition to the Lo clutch mechanism C_Lo, the routine is temporarily terminated. Conversely, if a positive judgment is made in step S2 because only the Lo clutch mechanism C_Lo is engaged, the engine starting threshold is increased by a predetermined value from the normal value when the above conditions are not met (step S3), and the routine is temporarily terminated. This engine starting threshold is a threshold used to determine the switch from EV driving mode to HV driving mode, and can take accelerator opening, required driving force determined based on accelerator opening and vehicle speed as parameters. That is, when the required driving force or required driving power is greater than or equal to the engine starting threshold, the engine 3 is started. It should be noted that this engine starting threshold is equivalent to the "starting determination value" in the embodiments of the present invention.

[0092] Here, the range of driving force required for setting the EV driving mode is defined as the range of power less than the power that can be output from the second motor 5. That is, the range in which EV driving mode can be performed is defined as the range obtained by subtracting a predetermined margin from the maximum output of the second motor 5. The power that can be output from the second motor 5 varies based on the battery storage device 30, the temperature of the second motor 5, or the remaining charge of the battery storage device 30. Therefore, the engine starting threshold in step S3 can also be a variable value that varies based on the temperature of the battery storage device 30, the second motor 5, or the remaining charge of the battery storage device 30.

[0093] In addition, the predetermined value can be appropriately determined within the aforementioned margin range. It can be a fixed value that has been predetermined, or a variable value that corresponds to the required driving force.

[0094] Figure 10 It means that it has been executed. Figure 9 The timing diagram shows the changes in driving mode and engine start threshold under the control example shown. Figure 10 At time t0, when the vehicle is stopped, the gear shift position becomes Parking (P). Therefore, since at... Figure 9 In step S1, a negative judgment is made, therefore the engine starting threshold is set to a predetermined value that is the usual value. It should be noted that when the car is stopped, the frequency of switching to forward gear is high, therefore the Lo clutch mechanism C_Lo is engaged.

[0095] At time t1, if the gear lever is switched to reverse (R), then at... Figure 9 In step S1, a positive judgment is made. Furthermore, since the Lo clutch mechanism C_Lo remains engaged from time t0, a positive judgment is also made in step S2. As a result, the engine starting threshold is increased by a predetermined value at time t1.

[0096] When the reverse gear is selected as described above and the Lo clutch mechanism C_Lo is engaged, by increasing the engine start threshold, the driving range in EV mode is expanded compared to the case where the engine start threshold is not increased. That is, it is possible to drive using only the second motor 5, which outputs a greater driving force than when the engine start threshold is not increased. As a result, when the engine 3 is stopped and the Lo clutch mechanism C_Lo is engaged, reverse driving can be performed using only the power of the second motor 5, shortening the time from selecting the reverse gear to starting reverse driving. Furthermore, when the Hi clutch mechanism C_Hi is a meshing clutch mechanism, it is possible to suppress the engagement of the Hi clutch mechanism C_Hi when the vehicle is stopped, thus reducing driver discomfort caused by the engagement sound.

[0097] Figure 11This is a flowchart illustrating another example of the driving force control device in an embodiment of the present invention, performing... Figure 9 The same steps as steps S1 and S2 are performed. Then, if a positive judgment is made in step S2 because the Lo clutch mechanism C_Lo is engaged, the charging start threshold is lowered by a predetermined value from the charging start threshold under the condition that the conditions of steps S1 and S2 are not met, i.e., the predetermined normal value (step S13), and the routine is temporarily terminated. This charging start threshold is a predetermined remaining amount that is determined to start the engine 3 and begin charging the battery storage device 30 in order to suppress the depletion of the SOC of the battery storage device 30. That is, it is determined to be a value with a predetermined surplus amount higher than the lower limit of the SOC. Therefore, the predetermined value in step S13 can be appropriately determined within the range of the surplus amount, and can be either a predetermined fixed value or a variable value that varies based on the discharge power corresponding to the required driving force. It should be noted that this charging start determination value is equivalent to the "start determination value" in the embodiments of the present invention.

[0098] Figure 12 It means that it has been executed. Figure 11 The timing diagram shows the changes in driving mode and charging start threshold under the control example shown. Figure 12 At time t10, the gear shifts to Park (P) when the vehicle is stopped. Therefore, at... Figure 11 In step S1, a negative judgment is made, therefore the charging start threshold is set to a predetermined SOC value. It should be noted that when the vehicle is parked, the frequency of shifting to forward gear is high, so the Lo clutch mechanism C_Lo is engaged.

[0099] At time t11, if the gear lever is operated to switch to reverse (R), then at... Figure 11 In step S1, a positive judgment is made. Furthermore, since the Lo clutch mechanism C_Lo remains engaged from time t10, a positive judgment is also made in step S2. As a result, the charging start threshold is lowered by a predetermined value at time t11.

[0100] As described above, when the reverse gear is selected and the Lo clutch mechanism C_Lo is engaged, by lowering the charging start threshold, it is possible to suppress situations where the engine 3 starts before the reverse gear is selected, such as when the SOC decreases and charging begins while the vehicle is stationary. As a result, when the reverse gear is selected, the torque of the engine 3 acting on the front wheels 1R and 1L can be suppressed, allowing reverse driving to begin without switching the engaged clutch mechanism. That is, the time from selecting the reverse gear to starting reverse driving can be shortened. Furthermore, even if the SOC decreases due to driving using only the power of the second motor 5, starting the engine 3 can be suppressed, thus suppressing the decrease in driving force during reverse driving.

[0101] It should be noted that the driving force control device in the embodiments of the present invention is not limited to changing the engine starting threshold or the charging start threshold, but can be any parameter that changes the way in which the engine 3 is difficult to start to become the main reason for starting the engine 3. Alternatively, it can also be... Figure 9 The control example shown is similar to Figure 11 The control example shown is executed in combination. That is, it can also be configured to increase the engine start threshold and decrease the charging start threshold when reversing. By configuring it in this way, it is possible to suppress engine 3 from starting due to either condition being met.

[0102] Next, a control example will be explained to suppress the reduction of driving force during reverse driving by reducing the torque output from engine 3 and not switching the clutch mechanism to be engaged. Figure 13 This is a flowchart illustrating an example of this control, execution and Figure 9 and Figure 11 The steps S1 and S2 are the same. Then, if a positive judgment is made in step S2 because the Lo clutch mechanism C_Lo is engaged, it is determined whether the engine 3 is being driven (step S23). This step S23 can be determined based on the output signal of the fuel injection device or the like that supplies fuel to the engine 3.

[0103] If a negative judgment is made in step S23 due to engine 3 stopping, the routine is temporarily terminated directly. Conversely, if a positive judgment is made in step S23 due to engine 3 driving, the output power of engine 3 is maintained, and the engine speed is increased from the normal value (where the conditions of steps S1 and S2 are not met) (step S24), and the routine is temporarily terminated. In other words, while maintaining the output power of engine 3, the output torque of engine 3 is reduced from the normal value (where the conditions of steps S1 and S2 are not met). Specifically, the engine speed in step S24 is determined by increasing the engine speed so that the torque transmitted to the front wheels 1R and 1L via the power distribution mechanism 6 when the Lo clutch mechanism C_Lo is engaged is equal to the torque transmitted to the front wheels 1R and 1L via the power distribution mechanism 6 when the engine speed is controlled at a fuel-efficient speed and the HV-Hi mode is set.

[0104] Figure 14 It means that it has been executed. Figure 13 The timing diagram shows the changes in driving mode, the indicator that enables engine 3 to operate, engine speed, and output torque of engine 3 under the control example shown. Figure 14 At time t20, the gear position is Park (P). Therefore, at... Figure 13The process ends directly after making a negative judgment in step S1. Figure 13 The example program is shown. It should be noted that at time t20, engine 3 is stopped.

[0105] At time t21, if the gear lever is operated to switch to reverse (R), then at... Figure 13 In step S1, a positive judgment is made. Additionally, in... Figure 14 In the example shown, the engine 3 start flag is switched to ON simultaneously with the gear shift. Therefore, from time t22, the engine speed and engine torque begin to increase.

[0106] By operating engine 3 like this, in Figure 13 In step S23, a positive judgment is made. As a result, the engine speed increases to a level higher than if no action is taken. Figure 13 In the case of the control example, the engine speed (dashed line) is a high speed. In addition, in order to maintain the output power of engine 3, the engine torque is maintained proportionally and not executed. Figure 13 The engine torque (dashed line) is low under the control example.

[0107] When the engine speed is increased in this way, the speed of the first motor 4 also increases, and the engine torque decreases, thereby reducing the reaction torque of the first motor 4. Therefore, the electrical power generated by the first motor 4 does not vary significantly depending on whether the engine speed is increased.

[0108] When the reverse gear is selected and the Lo clutch mechanism C_Lo is engaged as described above, the engine speed is controlled to a speed higher than the fuel-efficient speed of engine 3, maintaining the output power of engine 3 and reducing engine torque, thereby suppressing the increase in torque that counteracts the torque used for reverse driving. Therefore, reverse driving can be performed with the Lo clutch mechanism C_Lo engaged, shortening the time from the request to shift gears to the start of driving. Furthermore, even when driving engine 3 in reverse with the Lo clutch mechanism C_Lo engaged as described above, the reduction in driving force during reverse driving can be suppressed by reducing the output torque of engine 3.

[0109] In the HV driving mode described above, where engine 3 is driven, the total power output from engine 3 is the sum of the power required to drive the hybrid vehicle and the power required to charge the energy storage device 30. In other words, by temporarily reducing the power required to charge the energy storage device 30, the required output power of engine 3 can be reduced. As a result, even when engine 3 is operated at a fuel-efficient speed, the output torque of engine 3 can be reduced compared to the case where the power required to charge the energy storage device 30 is not reduced.

[0110] Therefore, the drive force control device in the embodiments of the present invention can also reduce the power required to charge the energy storage device 30 when reversing in a state where the Lo clutch mechanism C_Lo is engaged. Figure 15 The diagram shows a flowchart illustrating an example of this control. Figure 15 In the example shown, with Figure 9 , Figure 11 as well as Figure 13 Similarly, in the control example shown, steps S1 and S2 are executed, and when a positive judgment is made in step S2, the control proceeds in accordance with the control procedure. Figure 13 The control example shown similarly determines whether engine 3 is driving (step S23).

[0111] If a negative judgment is made in step S23 due to engine 3 stopping, the routine is temporarily terminated directly. Conversely, if a positive judgment is made in step S23 due to engine 3 driving, the charging requirement for charging the energy storage device 30 is reduced compared to the normal value when the conditions of steps S1 and S2 are not met (step S34), and the routine is temporarily terminated. In other words, the output power of engine 3 is reduced. Specifically, when engine 3 is operated with a total power obtained by adding the power required to drive the hybrid vehicle to the charging requirement reduced in step S34, the engine speed is controlled at a speed that is fuel-efficient for engine 3.

[0112] Figure 16 It means that it has been executed. Figure 15 The timing diagram shows the changes in driving mode, the indicator that enables engine 3 to operate, the charge requirement, engine speed, and the output torque of engine 3 under the control example shown. Figure 16 At time t30, the gear is in Park (P). Therefore, since at... Figure 15 The process ends directly after making a negative judgment in step S1. Figure 16 The example shown. It should be noted that at time t30, engine 3 is stopped.

[0113] At time t31, if the gear lever is operated to switch to reverse (R), at Figure 15 In step S1, a positive judgment is made. On the other hand, in Figure 16 In the example shown, the flag that starts engine 3 at the moment of gear shifting is OFF. Therefore, at time t31, engine 3 remains stationary.

[0114] Next, at time t32, the flag for starting engine 3 is switched to "on". Therefore, at Figure 15 In step S23, a positive judgment is made. As a result, although the charging requirement increases from 0, the charging requirement (solid line) is set lower than if no action is taken. Figure 15 The charging requirement (dashed line) is low under the control example. Therefore, although the engine speed and engine torque increase from time t33, the engine speed and engine torque are maintained at a level lower than when no control is executed. Figure 15 In the case of control example, the engine speed and engine torque are low.

[0115] When the reverse gear is selected and the Lo clutch mechanism C_Lo is engaged as described above, by reducing the charging demand, the engine torque can be reduced even when the engine 3 is controlled at a speed that promotes good fuel economy. Therefore, the increase in torque that counteracts the torque used for reverse driving can be suppressed. As a result, reverse driving can be performed with the Lo clutch mechanism C_Lo engaged, shortening the time from the gear shift request to the start of driving. Furthermore, even when the engine 3 is driven in reverse with the Lo clutch mechanism C_Lo engaged as described above, the reduction in the driving force during reverse driving can be suppressed by reducing the output torque of the engine 3.

[0116] The above Figure 9 and Figure 11 The control example shown is configured to make it difficult to start the engine 3 by changing the determination threshold that is the main reason for starting the engine 3. In contrast, Figure 13 and Figure 15 The control example shown is configured to reduce the output torque of engine 3 after engine 3 starts compared to the case when the front wheels are moving and the Hi clutch mechanism C_Hi is engaged. Therefore, it can also be configured based on Figure 9 , Figure 11 The control example shown modifies the threshold for starting engine 3. If the required driving force and SOC change due to exceeding the modified threshold, the following actions are executed. Figure 13 , Figure 15 The control example shown. Alternatively, it can be combined with... Figure 9 , Figure 11 The control example shown is executed in parallel. Figure 13 , Figure 15 The control example shown.

[0117] In addition, Figure 9 , Figure 11 as well as Figure 15 In the control example shown, compared to normal conditions, the power output from the energy storage device 30 is greater, or the state of charge (SOC) of the energy storage device 30 is lowered. If the Lo clutch mechanism C_Lo is kept engaged for a long period of time, the durability of the energy storage device 30 may decrease. Furthermore, in Figure 13 In the control example shown, the engine 3 is driven at a point where fuel economy is optimal, which may worsen fuel economy. Therefore, after a predetermined period of reverse driving, the clutch mechanism to be engaged can be switched from the Lo clutch mechanism C_Lo to the Hi clutch mechanism C_Hi.

[0118] Figure 17 , Figure 19 , Figure 21 as well as Figure 23 This is a flowchart used to illustrate this control example. Figure 17 The control example shown is similar to Figure 9 The control example shown similarly increases the engine starting threshold by a predetermined value (step S3). Next, after a predetermined period, the clutch mechanism to be engaged is switched from the Lo clutch mechanism C_Lo to the Hi clutch mechanism C_Hi (step S4). Specifically, the Lo clutch mechanism C_Lo is first released. Next, the speed difference between the planetary carrier 18 and the ring gear 16 is reduced to below a predetermined difference by controlling the speed of the first motor 4. When reversing while the Lo clutch mechanism C_Lo is engaged, the first motor 4 rotates in the opposite direction to the engine 3, and the planetary carrier 18 rotates in the opposite direction to the ring gear 16. Therefore, by rotating the first motor 4 in the same direction as the engine 3, the speed difference between the planetary carrier 18 and the ring gear 16 can be reduced. Then, at the moment when the speed difference between the planetary carrier 18 and the ring gear 16 becomes below the predetermined difference, the Hi clutch mechanism C_Hi is engaged. It should be noted that, as described above, in order to suppress the decrease in the durability of the energy storage device 30, the clutch mechanism to be engaged is switched to the Hi clutch mechanism C_Hi. Therefore, the above-mentioned predetermined period is the period during which the hybrid vehicle is driving backward, excluding the period when it is stopped.

[0119] By switching the clutch mechanism to be engaged from the Lo clutch mechanism C_Lo to the Hi clutch mechanism C_Hi as described above, even if the engine 3 starts and outputs torque, the torque transmitted to the front wheels 1R and 1L via the power distribution mechanism 6 can be reduced compared to the case where the Lo clutch mechanism C_Lo is engaged. Therefore, in step S4, the increased engine starting threshold is restored to the normal value α (step S5), and the routine is temporarily terminated. That is, the engine starting threshold is set to the same value as in the case where a negative judgment was made in steps S1 and S2 above. It should be noted that when the gear shift is changed to a forward gear, the engine starting threshold is also restored to the normal value α.

[0120] Figure 18 It means that it has been executed. Figure 17 The timing diagram shows the changes in driving mode and engine start threshold under the control example shown. Figure 18 In the example shown, with Figure 10 Similarly, in the example shown, the engine starting threshold is increased (at time t1). Next, if a predetermined period elapses from the increase in the engine starting threshold (at time t2), step S4 is executed, thereby releasing the Lo clutch mechanism C_Lo and engaging the Hi clutch mechanism C_Hi. That is, the driving mode is switched to Hi mode. Then, at time t3, the engine starting threshold is reduced to its normal value α.

[0121] By restoring the engine starting threshold to its normal value after a predetermined period of reverse driving as described above, the load on the battery storage device 30 can be reduced, thereby suppressing a decrease in the durability of the battery storage device 30. Furthermore, even when the engine 3 is started by restoring the engine starting threshold to its normal value, the torque transmitted via the power distribution mechanism 6 can be reduced, thus suppressing a decrease in driving force. Moreover, in the case where the Hi clutch mechanism C_Hi is configured with an engaging clutch mechanism, since the Hi clutch mechanism C_Hi is engaged during driving, even if a locking sound is produced, driver discomfort can be suppressed.

[0122] Figure 19 This is a flowchart illustrating a control example that, after a predetermined period of reverse driving, switches the clutch mechanism to be engaged to the Hi clutch mechanism C_Hi, and restores the reduced charging start threshold to its normal value. Figure 19 The control example shown is similar to Figure 11 Similarly, in the control example shown, the charging start threshold is lowered by a predetermined value (step S13). Next, after a predetermined period, the clutch mechanism to be engaged is switched from the Lo clutch mechanism C_Lo to the Hi clutch mechanism C_Hi (step S14). Step S14 is the same as step S4 described above.

[0123] By switching the clutch mechanism to be engaged from the Lo clutch mechanism C_Lo to the Hi clutch mechanism C_Hi as described above, even if the engine 3 starts and outputs torque, the torque transmitted to the front wheels 1R and 1L via the power distribution mechanism 6 can be reduced compared to the case where the Lo clutch mechanism C_Lo is engaged. Therefore, in step S14, the reduced charging start threshold is restored to its normal value (step S15), and the routine is temporarily terminated. That is, the charging start threshold is set to the same value as the case where a negative judgment was made in steps S1 and S2 above. It should be noted that when the gear shift is changed to a forward gear, the charging start threshold is also restored to its normal value.

[0124] Figure 20 It means that it has been executed. Figure 19 The timing diagram shows the changes in driving mode and charging start threshold under the control example shown. Figure 20 In the example shown, with Figure 12 Similarly, in the example shown, the charging start threshold is lowered (at time t11). Next, if a predetermined period has elapsed since the charging start threshold was lowered (at time t12), then by executing step S14 above, the Lo clutch mechanism C_Lo is released and the Hi clutch mechanism C_Hi is engaged. That is, the driving mode is switched to Hi mode. Then, at time t13, the charging start threshold is increased to the normal value α.

[0125] By restoring the charging start threshold to its normal value after a predetermined period of reverse driving as described above, the load on the battery storage device 30 can be reduced, thereby suppressing a decrease in the durability of the battery storage device 30. Furthermore, even if the engine 3 is started after restoring the charging start threshold to its normal value, the torque transmitted via the power distribution mechanism 6 can be reduced, thus suppressing a decrease in driving force. Moreover, in the case where the Hi clutch mechanism C_Hi is configured with an engaging clutch mechanism, the Hi clutch mechanism C_Hi is engaged during driving, so even if a locking sound is produced, driver discomfort can be suppressed.

[0126] Figure 21 This is a flowchart illustrating a control example that, after a predetermined period of reverse driving, switches the clutch mechanism to be engaged to the Hi clutch mechanism C_Hi, and restores the increased engine speed to the normal speed. Figure 21 The control example shown is similar to Figure 13The control example shown similarly increases the engine speed (step S24). Next, after a predetermined period, the clutch mechanism to be engaged is switched from the Lo clutch mechanism C_Lo to the Hi clutch mechanism C_Hi (step S25). This step S25 is the same as steps S4 and S14 described above.

[0127] By switching the clutch mechanism to be engaged from the Lo clutch mechanism C_Lo to the Hi clutch mechanism C_Hi as described above, the torque transmitted to the front wheels 1R and 1L via the power distribution mechanism 6 is reduced compared to when the Lo clutch mechanism C_Lo is engaged. Therefore, in step S25, the increased engine speed is restored to the normal speed (step S26), and the routine is temporarily terminated. That is, the engine speed is controlled to a speed at which the engine 3 is fuel-efficient. It should be noted that when the gear shift is changed to a forward gear, the engine speed is also restored to the normal value.

[0128] Figure 22 It means that it has been executed. Figure 21 The diagram shows the timing of changes in the driving mode, the indicator that enables engine 3, the engine speed, and the output torque of engine 3 under the control example shown. Figure 22 In the example shown, with Figure 14 Similarly, in the example shown, at time t22, the engine speed begins to increase. Then, at time t23, the engine speed increases to a target speed, which is higher than the normal engine speed. Next, if a predetermined period (time t24) has elapsed since the engine speed increased to the target speed, step S25 described above is executed, thereby releasing the Lo clutch mechanism C_Lo and engaging the Hi clutch mechanism C_Hi. That is, the driving mode is switched to Hi mode. Then, at time t25, the engine speed decreases to the normal speed. It should be noted that in order to maintain the output power of engine 3, the engine torque increases as the engine speed decreases.

[0129] By restoring the engine speed to its normal speed after a predetermined period of reverse driving as described above, the deterioration of the fuel economy of engine 3 can be suppressed. Furthermore, even if the engine torque increases as the engine speed is restored to its normal speed, the torque transmitted via the power distribution mechanism 6 can be reduced, thus suppressing a decrease in driving force. Moreover, in the case where the Hi clutch mechanism C_Hi is configured with an engaging clutch mechanism, the Hi clutch mechanism C_Hi is engaged during driving, so even if a locking sound is produced, driver discomfort can be suppressed.

[0130] Figure 23This is a flowchart illustrating a control example that, after a predetermined period of reverse driving, switches the clutch mechanism to be engaged to the Hi clutch mechanism C_Hi, and restores the reduced charging demand to its normal value. Figure 23 The control example shown is achieved by performing a control with... Figure 15 The control example shown uses the same steps to reduce the charging requirement (step S34). Next, after a predetermined period, the clutch mechanism to be engaged is switched from the Lo clutch mechanism C_Lo to the Hi clutch mechanism C_Hi (step S35). This step S35 is the same as steps S4, S14, and S25 described above.

[0131] By switching the clutch mechanism to be engaged from the Lo clutch mechanism C_Lo to the Hi clutch mechanism C_Hi as described above, the torque transmitted to the front wheels 1R and 1L via the power distribution mechanism 6 is reduced compared to the case where the Lo clutch mechanism C_Lo is engaged. Therefore, in step S35, the reduced charging demand is restored to the normal demand (step S36), and the routine is temporarily terminated. That is, the charging demand is set to the same level as in the case where a negative judgment was made in steps S1 and S2 above. It should be noted that when the gear shift is changed to a forward gear, the charging demand is also restored to the normal value.

[0132] Figure 24 It means that it has been executed. Figure 23 The timing diagram shows the changes in driving mode, the indicator that enables engine 3 to operate, the charge requirement, engine speed, and the output torque of engine 3 under the control example shown. Figure 24 In the example shown, with Figure 16 Similarly, in the example shown, at time t33, the engine speed begins to increase. Then, at time t34, the engine speed increases to a target speed, which is lower than the normal engine speed. Next, if a predetermined period (time t35) has elapsed since the engine speed increased to the target speed, step S35 is executed, thereby releasing the Lo clutch mechanism C_Lo and engaging the Hi clutch mechanism C_Hi. That is, the driving mode is switched to Hi mode. Then, at time t36, the charging demand returns to the normal demand, thereby increasing the engine speed to the normal speed. It should be noted that in order to drive the engine 3 at its fuel-efficient operating point, the engine torque increases along with the increase in the output power of the engine 3.

[0133] By restoring the charging demand to its normal level after a predetermined period of reverse driving as described above, excessive reduction in the remaining charge of the battery storage device 30 can be prevented. Furthermore, even if engine torque increases as the charging demand is restored to its normal value, the torque transmitted via the power distribution mechanism 6 can be reduced, thus suppressing a decrease in driving force. Moreover, in the case where the Hi clutch mechanism C_Hi is configured with an engaging clutch mechanism, the Hi clutch mechanism C_Hi is engaged during driving, so even if a locking sound is produced, driver discomfort can be suppressed.

[0134] Figures 3 to 23 The control examples are designed to suppress the reduction in driving force caused by the torque transmitted from the engine 3 to the front wheels 1R and 1L via the power distribution mechanism 6 in the forward direction opposing the torque output from the second motor 5 for reverse driving. The engine 3 starts primarily because the state of charge (SOC) of the battery storage device 30 is low, resulting in low electrical output from the battery storage device 30. Therefore, the aforementioned controls only need to be executed during reverse driving when high driving force is required.

[0135] exist Figure 25 The diagram shows a flowchart illustrating an example of this control. Figure 25 The control example shown is configured to execute the following when reversing on an uphill road: Figure 9 The control example shown is as follows. Specifically, firstly, it is determined whether the current position is a slope (step S6). This step S6 is used to determine whether a situation requiring high driving force is encountered when reversing. Therefore, in step S6, it is determined whether the road is uphill when reversing. In other words, the situation of an uphill road when moving forward is excluded. This step S6 can be based on the detection values ​​of various sensors installed in the hybrid vehicle, such as acceleration sensors and radar, or on location information such as GPS and IP address. In addition, while step S6 determines whether the current position is a slope, it can also determine, for example, whether there is an uphill road within a predetermined distance that is encountered when reversing. Moreover, it is not limited to slopes; for example, it can also determine whether the environment requiring high driving force is encountered when reversing, such as crossing steps.

[0136] If a negative judgment is made in step S6 because the current location is not a ramp, the operation is not performed. Figure 9 The control example shown temporarily terminates the routine. Conversely, if a positive judgment is made in step S6 because the current position is a ramp, the procedure is executed. Figure 9 The control example shown is as follows: The process proceeds to step S1, where it is determined whether the driving gear is reverse driving gear.

[0137] In situations where high driving force is required for driving on slopes or where high driving force may be required, by changing the engine start threshold, engine speed, or charging requirement, the durability of the battery storage device 30 can be suppressed, or the fuel economy can be suppressed.

[0138] Furthermore, if the State of Charge (SOC) of the energy storage device 30 is maintained at a high level at the moment reverse travel begins, the electrical power output from the energy storage device 30 to the second motor 5 can be increased. That is, high driving force can be obtained when reverse travel is performed using only the second motor 5 as the driving force source, and its travel time (or distance) can be extended. Therefore, the driving force control device in the embodiment of the present invention is configured to increase the SOC when it is possible to travel uphill by reverse travel.

[0139] exist Figure 26 The diagram shows a flowchart illustrating an example of this control. Figure 26 In the control example shown, the system first determines whether the current location is one where there is a possibility of traveling uphill by reversing. That is, it determines whether the vehicle is approaching a slope (step S41). This step S41 can be based on location information such as GPS and IP address, or on past driving history stored in the ECU31. It should be noted that in this control example, the hybrid vehicle can travel either forward or backward.

[0140] If a negative judgment is made in step S41 due to not approaching the ramp, the routine is temporarily terminated. Conversely, if a positive judgment is made in step S41 due to approaching the ramp, it is determined whether the SOC is less than a predetermined SOC value (step S42). The predetermined SOC value in step S42 is more than... Figure 11 The charging start threshold value in step S13 is more specifically the SOC value required for reversing and stopping on an uphill road using only the second motor 5 as the driving force source. It should be noted that the SOC can be determined based on the signal from the sensor that detects the SOC, the output voltage of the energy storage device 30, etc.

[0141] If a negative judgment is made in step S42 because the SOC is above the predetermined SOC value, the routine is temporarily terminated because sufficient electricity is supplied to the battery storage device 30 for reversing, using only the second motor 5 as the driving force source. Conversely, if a positive judgment is made in step S42 because the SOC is below the predetermined SOC value, it is determined whether the engine 3 is being driven (step S43). Step S43 is the same as step S23 described above.

[0142] If a positive determination is made in step S43 because engine 3 is running, the charging demand is increased by a predetermined amount (step S44), and the routine is temporarily terminated. That is, by increasing the output power of engine 3, the power generated by the first motor 4 is increased, thereby promoting the charging of the energy storage device 30. In other words, the charging power of the energy storage device 30 is increased. It should be noted that the predetermined amount can also be a variable value that varies based on the difference between the current SOC value and the predetermined SOC value, the distance to the ramp, etc.

[0143] Conversely, if a negative judgment is made in step S43 because engine 3 is not driven, engine 3 is started (step S45), and the process proceeds to step S44.

[0144] It should be noted that, after charging the storage device 30 by increasing the charging demand as described above, and when the SOC becomes sufficiently high and the driving gear is switched to R, the engine 3 can also be stopped.

[0145] Figure 27 It means that it has been executed. Figure 26 The timing diagrams shown illustrate the changes in SOC determination, ramp determination, engine 3 drive status, charging demand, engine speed, and engine torque under the control example illustrated. It should be noted that... Figure 27 The example shown is an example of starting the engine 3 and charging the battery storage device 30 by performing the above-described step S45 from a state where the engine 3 is stopped and the vehicle is in motion.

[0146] Therefore, at time t40, engine 3 stops, and the engine speed and engine torque are maintained at 0. Additionally, at time t40, the ramp determination flag (hereinafter referred to as the ramp determination flag) is set to off because the ramp is not approached. Moreover, at time t40, the SOC is sufficiently high, therefore, the SOC determination flag in step S42 above, which determines whether the SOC is higher than a predetermined SOC value, becomes Hi.

[0147] At time t41, the ramp determination flag is switched to "on" due to the approaching ramp. On the other hand, at time t41, the SOC determination flag is still "Hi," so a negative determination is made in step S42 above. Therefore, engine 3 remains in a stopped state.

[0148] At time t42, the SOC determination flag switches to Lo. Therefore, a positive determination is made in step S42. On the other hand, at time t42, a negative determination is made in step S43 because engine 3 has stopped. Therefore, engine 3 starts (at time t43). As a result, at time t43, engine speed and engine torque begin to increase. In addition, the charging requirement used to determine the output power of engine 3 is increased compared to the normal charging requirement by performing step S44.

[0149] Therefore, in order to suppress the deterioration of fuel economy as the output power of engine 3 increases, engine speed and engine torque will be controlled as target values ​​(solid lines) that are higher than the target speed (dashed line) and target torque (dashed line) without increasing the charging demand.

[0150] By increasing the charging demand as described above when approaching a slope, the charging of the battery storage device 30 is promoted, thereby maintaining a high state of charge (SOC) of the battery storage device 30 when reversing uphill begins. Therefore, the electrical power output from the battery storage device 30 to the second motor 5 is increased. That is, high driving force is obtained when reversing using only the second motor 5 as the driving force source, and its driving time (or distance) is extended. Therefore, reversing uphill is possible with the engine 3 stopped. In other words, reversing can be performed without switching the engaged clutch mechanism, thus shortening the time from shifting from driving gear to reverse gear to starting reversing.

[0151] It should be noted that even if implemented Figure 26 The control example shown increases the State of Charge (SOC). If the reverse travel distance (or time) is long, or if the required driving force for reverse travel is higher than assumed, engine 3 will also start. Therefore, it can also be configured to perform the above-described actions simultaneously. Figures 3 to 25 The control example shown.

[0152] This invention is not limited to the embodiments described above, and can be appropriately modified without departing from the purpose of this invention. Therefore, the hybrid vehicle that is the object of this invention can be configured with at least two driving modes in which the ratio of the torque transmitted to the first rotating motor (first motor) side is different from the ratio of the torque transmitted to the output member (drive wheel) side, and can be a hybrid vehicle with a structure in which the torque transmitted to the output member side via the power distribution mechanism acts in the direction of reducing the driving force for reverse driving. Specifically, it is "a vehicle comprising: a first differential mechanism that connects a first rotating component and a second rotating component to a third rotating component in a differentially rotatable manner, wherein the first and second rotating components are two of a rotating component connected to an engine, a rotating component connected to a motor, and a rotating component connected to a drive wheel; a second differential mechanism that connects a fourth rotating component, a fifth rotating component connected to the third rotating component, and a sixth rotating component in a differentially rotatable manner, wherein the fourth rotating component is another rotating component connected to an engine, a rotating component connected to a motor, and a rotating component connected to a drive wheel; the first..." A locking mechanism sets a low mode where the torque transmitted from the engine to the drive wheel is greater by engaging one of the first rotating component pair and the second rotating component pair, wherein the first rotating component pair is a pair of rotating components of the first rotating component and the second rotating component and the sixth rotating component, and the second rotating component pair is any one of the fourth rotating component, the fifth rotating component, and the sixth rotating component; and a second locking mechanism sets a high mode where the torque transmitted from the engine to the drive wheel is less than the low mode by engaging the other rotating component pair of the first rotating component pair and the second rotating component pair.

Claims

1. A drive force control device of a hybrid vehicle, characterized by comprising: Possessing: an engine; a first rotary electric machine; a transmission mechanism configured to link a first rotary member of the engine, a second rotary member of the first rotary electric machine, and a third rotary member of an output member in a manner that enables differential rotation, and output a reaction torque from the first rotary electric machine, thereby transmitting torque from the engine to the output member, and capable of setting a low mode in which a proportion of torque transmitted to the output member side among torque output from the engine is a first predetermined value, and a high mode in which the proportion is a second predetermined value smaller than the first predetermined value; a second rotary electric machine linked to the output member in a manner that enables transmission of torque; and a power storage device electrically connected to the first rotary electric machine and the second rotary electric machine, the drive force control device of the hybrid vehicle is configured to perform reverse travel by outputting a reverse torque from the second rotary electric machine, in a case where the engine is being driven, torque transmitted from the engine to the output member via the transmission mechanism is opposed to the reverse torque, wherein the drive force control device of the hybrid vehicle possesses a controller that controls the engine, the first rotary electric machine, and the second rotary electric machine, the controller, in a case where the transmission mechanism is set to the low mode and a restriction condition in which a travel range is selected to be a reverse travel range is satisfied, executes control that suppresses starting of the engine, wherein the control that suppresses starting of the engine includes changing a start determination value for determining starting of the engine in a manner that the engine is difficult to start compared to a case where the restriction condition is not satisfied, thereby expanding a region in which reverse travel is performed by only the second rotary electric machine.

2. The drive force control device of a hybrid vehicle according to claim 1, wherein the start determination value includes an engine start threshold value determined based on a required drive force or a required drive power of the hybrid vehicle, the controller is configured to start the engine in a case where the required drive force or the required drive power is the engine start threshold value or more, in the case where the restriction condition is satisfied, the controller increases the engine start threshold value compared to the case where the restriction condition is not satisfied.

3. The drive force control device of a hybrid vehicle according to claim 1, wherein the first rotary electric machine is configured to convert power transmitted from the engine into electric power, and supply the converted electric power to the power storage device, the start determination value includes a charge start threshold value for starting the engine based on a charge remaining amount of the power storage device, the controller is configured to start the engine in a case where the charge remaining amount is the charge start threshold value or less, in the case where the restriction condition is satisfied, the controller decreases the charge start threshold value compared to the case where the restriction condition is not satisfied.

4. The drive force control device of a hybrid vehicle according to any one of claims 1 to 3, wherein The controller is configured to determine the output power of the engine at the time when the engine is driven as a total power obtained by adding a drive power used to drive the hybrid vehicle and a charging power used to charge the electrical storage device, The controller reduces the output torque of the engine in a case where the limit condition is established.

5. The drive force control device of a hybrid vehicle according to claim 4, wherein The controller maintains the output power of the engine at the same level as in a case where the limit condition is not established while increasing the engine speed in a case where the limit condition is established, thereby reducing the output torque of the engine.

6. The drive force control device of a hybrid vehicle according to claim 4, wherein The controller sets the charging power lower in a case where the limit condition is established than in a case where the limit condition is not established, thereby reducing the output power of the engine and reducing the output torque of the engine.

7. The drive force control device of a hybrid vehicle according to any one of claims 1 to 3, wherein The controller is configured to also control the transmission mechanism, The controller switches the transmission mechanism from the low mode to the high mode and restores the changed start determination value to the start determination value in a case where the limit condition is not established, in a case where a predetermined period has elapsed since the hybrid vehicle is driven in reverse.

8. The drive force control device of a hybrid vehicle according to claim 4, wherein The controller is configured to also control the transmission mechanism, The controller switches the transmission mechanism from the low mode to the high mode and restores the reduced output torque of the engine to the output torque of the engine in a case where the limit condition is not established, in a case where a predetermined period has elapsed since the hybrid vehicle is driven in reverse.

9. The drive force control device of a hybrid vehicle according to any one of claims 1 to 3, wherein The controller determines whether the hybrid vehicle is driven in reverse on a high-load travel road on which a required drive force when the hybrid vehicle is driven in reverse is greater than a predetermined drive force, The controller changes the start determination value in a case where the hybrid vehicle is driven on the high-load travel road.

10. The drive force control device of a hybrid vehicle according to claim 4, wherein The controller determines whether the hybrid vehicle is driven in reverse on a high-load travel road on which a required drive force when the hybrid vehicle is driven in reverse is greater than a predetermined drive force, The controller reduces the output torque of the engine in a case where the hybrid vehicle is driven on the high-load travel road.

11. The drive force control device of a hybrid vehicle according to any one of claims 1 to 3, wherein The controller determines whether the hybrid vehicle is approaching a high-load travel road on which a required driving force during reverse travel is greater than a predetermined driving force, The controller increases the charging power of the electrical storage device in a case where the high-load travel road is approached, as compared with a case where the high-load travel road is not approached.

12. A drive force control device of a hybrid vehicle, characterized by comprising: Possessing: an engine; a first rotary electric machine; a transmission mechanism configured to link a first rotary member to which the engine is linked, a second rotary member to which the first rotary electric machine is linked, and a third rotary member to which an output member is linked in a manner capable of differential rotation, and output a reaction torque from the first rotary electric machine, thereby transmitting torque from the engine to the output member, and capable of setting a low mode in which a proportion of torque transmitted to the output member side among torque output from the engine is a first predetermined value and a high mode in which the proportion is a second predetermined value smaller than the first predetermined value; a second rotary electric machine linked to the output member in a manner capable of transmitting torque; and an electrical storage device electrically connected to the first rotary electric machine and the second rotary electric machine, the driving force control device of the hybrid vehicle is configured to perform reverse travel by outputting a reverse torque from the second rotary electric machine, in a case where the engine is being driven, torque transmitted from the engine to the output member via the transmission mechanism is opposed to the reverse torque, wherein the driving force control device of the hybrid vehicle possesses a controller that controls the engine, the first rotary electric machine, and the second rotary electric machine, the controller is configured to execute control for suppressing the engine torque opposition in a case where the low mode is set in the transmission mechanism and a restriction condition in which a travel range is selected to be a reverse travel range is satisfied, wherein the control for suppressing the engine torque opposition includes determining an output power of the engine at the time when the engine is driven to be a total power obtained by adding a driving power for driving the hybrid vehicle and a charging power for charging the electrical storage device, and the controller reduces an output torque of the engine, thereby suppressing torque transmitted via the transmission mechanism and opposed to the reverse torque, as compared with a case where the restriction condition is not satisfied.

13. The driving force control device of the hybrid vehicle according to claim 12, wherein in a case where the restriction condition is satisfied, the controller maintains the output power of the engine to be the same as in a case where the restriction condition is not satisfied, while increasing a rotational speed of the engine, thereby reducing the output torque of the engine.

14. The driving force control device of the hybrid vehicle according to claim 12, wherein the controller sets the charging power to be lower in a case where the restriction condition is satisfied than in a case where the restriction condition is not satisfied, thereby reducing the output power of the engine and reducing the output torque of the engine.

15. The driving force control device of the hybrid vehicle according to any one of claims 12 to 14, wherein The controller is configured to also control the transmission mechanism, In a case where a predetermined period elapses from the time when the hybrid vehicle is running in reverse, the controller switches the transmission mechanism from the low mode to the high mode and restores the reduced output torque of the engine to the output torque of the engine in a case where the limitation condition does not hold.

16. The drive force control device of a hybrid vehicle according to any one of claims 12 to 14, characterized in that The controller determines whether the hybrid vehicle is running in reverse on a high-load travel road on which a required drive force when running in reverse is greater than a predetermined drive force, The controller reduces the output torque of the engine when running on the high-load travel road.

17. The drive force control device of a hybrid vehicle according to any one of claims 12 to 14, characterized in that The controller determines whether the hybrid vehicle is approaching a high-load travel road on which a required drive force when running in reverse is greater than a predetermined drive force, The controller increases the charge power of the electric storage device when approaching the high-load travel road, as compared with a case where the high-load travel road is not approached.

18. The drive force control device of a hybrid vehicle according to claim 17, characterized in that The controller starts the engine and increases the charge power of the electric storage device when the engine is stopped at a time when the high-load travel road is approached.

19. A drive force control device of a hybrid vehicle, characterized by provided with: an engine; a first rotary electric machine; a transmission mechanism configured to link a first rotary member of the engine, a second rotary member of the first rotary electric machine, and a third rotary member of an output member in a manner that allows differential rotation, and output a reaction torque from the first rotary electric machine, thereby transmitting torque from the engine to the output member, and capable of setting a proportion of torque transmitted to the output member side among torque output from the engine to a first predetermined value in a low mode and to a second predetermined value smaller than the first predetermined value in a high mode; a second rotary electric machine linked to the output member in a manner that allows transmission of torque; and an electric storage device electrically connected to the first rotary electric machine and the second rotary electric machine, The drive force control device of the hybrid vehicle is configured to run in reverse by outputting a reverse torque from the second rotary electric machine, In a case where the engine is being driven, torque transmitted from the engine to the output member via the transmission mechanism is opposed to the reverse torque, wherein the drive force control device of the hybrid vehicle is provided with a controller that controls the engine, the first rotary electric machine, and the second rotary electric machine, The controller is configured to execute charge control for maintaining a retreating travel driving force, wherein the charge control includes determining whether the hybrid vehicle is approaching a high-load travel road on which a driving force required when retreating is greater than a predetermined driving force, and increasing charge power of the electric storage device to maintain sufficient power for retreating travel by only the second rotary electric machine on the high-load travel road, when the high-load travel road is approached.

20. The driving force control device of a hybrid vehicle according to claim 19, characterized in that, when the engine is stopped at a time when the high-load travel road is approached, the controller starts the engine to increase charge power of the electric storage device.

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