vehicle

Abstract

Perform appropriate evasive maneuvers. [Solution] The vehicle's processor, upon detection of an abnormality in the first motor generator and the second motor generator, performs the following processes: deriving an estimated value of the first on-brake torque that would act on the engine if the first on-control were performed at this time; deriving a first target torque that is greater than the current target torque of the engine by the estimated value of the first on-brake torque; deriving a delay time, which is the estimated time required for the current actual torque of the engine to reach the first target torque, assuming that the first target torque is set as the target torque of the engine at this time; setting the first target torque as the target torque of the engine; and starting the execution of the first on-control after the delay time has elapsed since the time the first target torque was set as the target torque of the engine.

Description

Technical Field

[0006] , , ,

[0001] The present invention relates to a vehicle.

Background Art

[0002] For example, Patent Document 1 discloses a hybrid vehicle having an engine, MG1, MG2, and a power split mechanism. In such Patent Document 1, when an abnormality in MG1 and MG2 is detected, by performing three-phase on control on MG1, dragging torque is generated in MG1, and thereby, it is possible to perform evacuation travel.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, when three-phase on control is performed, braking torque due to the dragging torque of MG1 acts on the engine. Therefore, depending on the rotational speed of the engine at the start time of the three-phase on control, when the three-phase on control is started, the rotational speed of the engine may decrease and the engine may stop. Then, it becomes impossible to appropriately perform evacuation travel.

[0005] Therefore, an object of the present invention is to provide a vehicle capable of appropriately performing evacuation travel.

Means for Solving the Problems

[0006] In order to solve the above problems, a vehicle according to an embodiment of the present invention includes a planetary gear mechanism having a sun gear, a ring gear, a planetary gear, and a carrier that rotatably supports the planetary gear, The engine connected to the aforementioned carrier, A first motor generator connected to the sun gear, The ring gear and the second motor generator connected to the axle, A first power converter electrically connected to the first motor generator, Control device and Equipped with, The first power converter includes a plurality of arms connected in parallel, Each of the plurality of arms includes a first switching element and a second switching element connected in series between a positive electrode wire and a negative electrode wire. The connection point between the first switching element and the second switching element is connected to the winding of the first motor generator. The control device is One or more processors, One or more memory connected to the processor, It has, The first ON control is a control that turns on one of the first switching element and the second switching element in common across the plurality of arms, and turns off the other of the first switching element and the second switching element in common across the plurality of arms. The brake torque acting on the engine due to the brake torque generated in the first motor generator when the first ON control is performed is the first ON brake torque. The aforementioned processor, In response to the detection of abnormalities in the first motor generator and the second motor generator, an estimated value of the first on-brake torque acting on the engine, assuming that the first on-control is performed at this time, is derived. To derive a first target torque that is greater than the current target torque of the engine by the estimated value of the first on-brake torque, Assuming that the first target torque is set as the target torque for the engine at this point in time, the delay time is estimated to be the time required for the actual torque of the engine at this point in time to reach the first target torque. Setting the first target torque as the target torque for the engine, The execution of the first ON control is started after the delay time has elapsed from the time the first target torque is set as the target torque of the engine, Execute the process that includes this. [Effects of the Invention]

[0007] According to the present invention, it becomes possible to perform evasive maneuvers appropriately. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing an example of the configuration of a vehicle according to the first embodiment. [Figure 2] Figure 2 is a circuit diagram showing an example of the electrical configuration of the first power converter and the first motor generator. [Figure 3] Figure 3 shows an example of a collinear diagram based on the gear ratio of a planetary gear mechanism. [Figure 4] Figure 4 is a flowchart showing an example of the operation flow of the vehicle control unit in the first embodiment. [Figure 5] Figure 5 shows an example of the first on-brake torque table. [Figure 6] Figure 6 is a graph showing the relationship between the rotational speed of the first motor generator and the first on-brake torque in the first on-brake torque table. [Figure 7] Figure 7 shows an example of a delay time map. [Figure 8] Figure 8 is a diagram illustrating the overview of the vehicle control according to the second embodiment. [Figure 9] Figure 9 is a flowchart showing an example of the operation flow of the vehicle control unit in the second embodiment. [Figure 10] FIG. 10 is a diagram showing an example of a duty ratio map. [Figure 11] FIG. 11 is a flowchart showing an example of the flow of operations of a vehicle control unit of a vehicle according to the third embodiment. [Figure 12] FIG. 12 is a flowchart showing an example of the flow of operations of a vehicle control unit of a vehicle according to the fourth embodiment. [Figure 13] FIG. 13 is a flowchart showing an example of the flow of operations of a vehicle control unit of a vehicle according to the fifth embodiment. [Figure 14] FIG. 14 is a diagram showing an example of a first upper limit value table. [Figure 15] FIG. 15 is a flowchart showing an example of the flow of operations of a vehicle control unit of a vehicle according to the sixth embodiment. [Figure 16] FIG. 16 is a diagram showing an example of a selection map.

BEST MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The specific dimensions, materials, numerical values, etc. shown in such embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same functions and configurations are denoted by the same reference numerals to omit redundant description, and elements not directly related to the present invention are not shown.

[0010] (First Embodiment) Figure 1 is a schematic diagram showing an example of the configuration of vehicle 1 according to the first embodiment. Vehicle 1 of the first embodiment includes a planetary gear 10, an engine 12, a first motor generator 14, a second motor generator 16, a reduction gear 18, a differential 20, an axle 22, wheels 24, a first power converter 26, a second power converter 28, a battery 30, a first resolver 32, a second resolver 34, an engine speed sensor 36, an accelerator sensor 38, a brake sensor 40, a vehicle speed sensor 42, a voltage sensor 44, a temperature sensor 46, and a control device 48. For convenience of explanation, the motor generator may be denoted as MG.

[0011] The planetary gear mechanism 10 includes a sun gear 50, a ring gear 52, planetary gears 54, and a carrier 56. The sun gear 50 is formed, for example, in the shape of a disc. The ring gear 52 is formed in the shape of a ring. The sun gear 50 is located inside the ring gear 52 and is arranged coaxially with the sun gear 50. One or more planetary gears 54 are provided between the sun gear 50 and the ring gear 52 and mesh with the sun gear 50 and the ring gear 52. The carrier 56 rotatably supports the planetary gears 54. The planetary gears 54 are capable of rotating on their own axis and revolving around the outer circumference of the sun gear 50. The carrier 56 converts the revolving of the planetary gears 54 into rotation of the carrier 56.

[0012] Engine 12 is, for example, a reciprocating engine and is the power source for vehicle 1. Engine 12 is connected to the carrier 56 of the planetary mechanism 10.

[0013] The first motor generator 14 is connected to the sun gear 50 of the planetary mechanism 10. The first motor generator 14 primarily functions as a generator that generates electricity in accordance with the drive of the engine 12, but it can also function as a motor.

[0014] The second motor generator 16 is connected to the reduction gear 18. The ring gear 52 of the planetary gear mechanism 10 is connected to the reduction gear 18. The reduction gear 18 is connected to the axle 22 via the differential 20. In other words, the second motor generator 16 is connected to the ring gear 52 and the axle 22. The axle 22 is connected to the wheel 24. The reduction gear 18 reduces the rotational speed of the ring gear 52 and the rotational speed of the second motor generator 16 and outputs it to the axle 22. The second motor generator 16 mainly functions as a motor that drives the vehicle 1, but it can also function as a generator.

[0015] The first power converter 26 is, for example, an inverter and is electrically connected to the first motor generator 14 and the battery 30. The first power converter 26 performs power conversion between the first motor generator 14 and the battery 30. The first power converter 26 will be described in detail later.

[0016] The second power converter 28 is, for example, an inverter and is electrically connected to the second motor generator 16 and the battery 30. The second power converter 28 performs power conversion between the second motor generator 16 and the battery 30. The specific configuration of the second power converter 28 is substantially the same as the specific configuration of the first power converter 26.

[0017] The battery 30 is a rechargeable secondary battery, such as a lithium-ion battery or a nickel-metal hydride battery. The battery 30 can supply power to the first motor generator 14 through the first power converter 26 and to the second motor generator 16 through the second power converter 28. The first motor generator 14 can charge the battery 30 through the first power converter 26. The second motor generator 16 can charge the battery 30 through the second power converter 28.

[0018] The first resolver 32 is provided, for example, on the rotating shaft of the first motor generator 14. The first resolver 32 detects the rotation angle of the first motor generator 14. The second resolver 34 is provided, for example, on the rotating shaft of the second motor generator 16. The second resolver 34 detects the rotation angle of the second motor generator 16. The engine speed sensor 36 is provided, for example, on the output shaft of the engine 12. The engine speed sensor 36 detects the rotation speed of the engine 12.

[0019] The accelerator sensor 38 detects the amount of accelerator operation by the driver. For example, the accelerator sensor 38 may detect the amount of accelerator operation by detecting the depression angle of an accelerator pedal (not shown). The brake sensor 40 detects the amount of brake operation by the driver. For example, the brake sensor 40 may detect the amount of brake operation by detecting the depression angle of a brake pedal (not shown). The vehicle speed sensor 42 detects the speed of the vehicle 1 (i.e., vehicle speed). For example, the vehicle speed sensor 42 may detect the vehicle speed by detecting the rotational speed of the wheels 24.

[0020] The voltage sensor 44 detects the terminal voltage of the battery 30. The temperature sensor 46 detects the temperature of the first motor generator 14.

[0021] The control device 48 includes one or more processors 60 and one or more memories 62 connected to the processors 60. The memories 62 include ROM, which stores programs, etc., and RAM as a work area. The memories 62 may also include storage, which stores programs, etc. The processors 60 cooperate with the programs contained in the memories 62 to function as a vehicle control unit 70.

[0022] The vehicle control unit 70 controls various parts of the vehicle 1. For example, the vehicle control unit 70 can control the engine 12. The vehicle control unit 70 can substantially control the first motor generator 14 by controlling the first power converter 26. The vehicle control unit 70 can substantially control the second motor generator 16 by controlling the second power converter 28.

[0023] Figure 2 is a circuit diagram showing an example of the electrical configuration of the first power converter 26 and the first motor generator 14. The electrical configurations of the second power converter 28 and the second motor generator 16 are substantially the same as those of the first power converter 26 and the first motor generator 14, and therefore their explanation is omitted.

[0024] As shown in Figure 2, the first motor generator 14 includes a U-phase winding 80U, a V-phase winding 80V, and a W-phase winding 80W. For convenience of explanation, the U-phase winding 80U, V-phase winding 80V, and W-phase winding 80W are sometimes collectively referred to simply as winding 80.

[0025] The U-phase winding 80U, the V-phase winding 80V, and the W-phase winding 80W are connected, for example, in a star connection. More specifically, one end of the U-phase winding 80U, one end of the V-phase winding 80V, and one end of the W-phase winding 80W are connected at the neutral point 82. Each winding 80 can generate a rotating magnetic field when current flows through it.

[0026] The first motor generator 14 is not limited to a three-phase motor containing windings 80 for three phases, but may also be a single-phase motor or a multi-phase motor other than three phases. In other words, the first motor generator 14 may contain one or more windings 80.

[0027] The first power converter 26 includes a U-phase arm 90U, a V-phase arm 90V, and a W-phase arm 90W. For convenience of explanation, the U-phase arm 90U, V-phase arm 90V, and W-phase arm 90W are sometimes collectively referred to simply as "arm 90."

[0028] The U-phase arm 90U includes a first U-phase switching element 92U, a second U-phase switching element 94U, a first U-phase diode 96U, and a second U-phase diode 98U. The first U-phase switching element 92U and the second U-phase switching element 94U are connected in series between the positive electrode wire 100 and the negative electrode wire 102. The connection point 104U between the first U-phase switching element 92U and the second U-phase switching element 94U is connected to the end of the U-phase winding 80U of the first motor generator 14 that is opposite to the neutral point 82. In other words, the first U-phase switching element 92U is located between the positive electrode wire 100 and the connection point 104U, and the second U-phase switching element 94U is located between the connection point 104U and the negative electrode wire 102.

[0029] The positive electrode wire 100 is electrically connected to the positive terminal of the battery 30. The negative electrode wire 102 is electrically connected to the negative terminal of the battery 30.

[0030] The first U-phase diode 96U is connected in reverse parallel to the first U-phase switching element 92U. The second U-phase diode 98U is connected in antiparallel to the second U-phase switching element 94U.

[0031] The V-phase arm 90V includes a V-phase first switching element 92V, a V-phase second switching element 94V, a V-phase first diode 96V, and a V-phase second diode 98V. The V-phase first switching element 92V and the V-phase second switching element 94V are connected in series between the positive terminal 100 and the negative terminal 102. The connection point 104V between the V-phase first switching element 92V and the V-phase second switching element 94V is connected to the end opposite to the neutral point 82 in the V-phase winding 80V of the first motor generator 14. In other words, the V-phase first switching element 92V is provided between the positive terminal 100 and the connection point 104V, and the V-phase second switching element 94V is provided between the connection point 104V and the negative terminal 102.

[0032] The first V-phase diode 96V is connected in reverse parallel to the first V-phase switching element 92V. The second V-phase diode 98V is connected in antiparallel to the second V-phase switching element 94V.

[0033] The W-phase arm 90W includes a first W-phase switching element 92W, a second W-phase switching element 94W, a first W-phase diode 96W, and a second W-phase diode 98W. The first W-phase switching element 92W and the second W-phase switching element 94W are connected in series between the positive electrode wire 100 and the negative electrode wire 102. The connection point 104W between the first W-phase switching element 92W and the second W-phase switching element 94W is connected to the end of the W-phase winding 80W of the first motor generator 14 that is opposite to the neutral point 82. In other words, the first W-phase switching element 92W is located between the positive electrode wire 100 and the connection point 104W, and the second W-phase switching element 94W is located between the connection point 104W and the negative electrode wire 102.

[0034] The first W-phase diode 96W is connected in reverse parallel to the first W-phase switching element 92W. The second W-phase diode 98W is connected in antiparallel to the second W-phase switching element 94W.

[0035] In this way, in the first power converter 26, a three-phase full-bridge circuit is formed by connecting the U-phase arm 90U, the V-phase arm 90V, and the W-phase arm 90W in parallel.

[0036] In Figure 2, since the first motor generator 14 is a three-phase motor, the first power converter 26 was configured to include three arms 90 that form a three-phase full-bridge circuit. However, the first power converter 26 is not limited to a configuration including three arms 90, and may also include multiple arms 90 that form a full-bridge circuit with the same number of phases as the first motor generator 14. In other words, the first power converter 26 may include multiple arms 90 connected in parallel.

[0037] For the sake of explanation, the U-phase first switching element 92U, the V-phase first switching element 92V, and the W-phase first switching element 92W may be collectively referred to simply as the first switching element 92. The U-phase second switching element 94U, the V-phase second switching element 94V, and the W-phase second switching element 94W may be collectively referred to simply as the second switching element 94. In addition, the first switching element 92 and the second switching element 94 may be collectively referred to simply as the switching element.

[0038] The vehicle control unit 70 can control the on / off state of each switching element of the first power converter 26. For example, as an example of the control mode of the first power converter 26, the vehicle control unit 70 can perform a first off control and a first on control.

[0039] The first off control is a control that turns off all of the first switching elements 92 and second switching elements 94 of the multiple arms 90 of the first power converter 26.

[0040] In the first off-control, all switching elements are turned off, so the three-phase full-bridge circuit including switching elements effectively becomes a three-phase full-bridge circuit consisting only of diodes. As a result, when the first motor generator 14 rotates during the first off-control, the power generated by the first motor generator 14 is regenerated into the battery 30.

[0041] The first ON control is a control that turns on one of the first switching element 92 and the second switching element 94 in common across multiple arms 90, and turns off the other of the first switching element 92 and the second switching element 94 in common across multiple arms 90. For example, in the first ON control, as shown in Figure 2, the U-phase first switching element 92U, the V-phase first switching element 92V, and the W-phase first switching element 92W are turned on, and the U-phase second switching element 94U, the V-phase second switching element 94V, and the W-phase second switching element 94W are turned off. Alternatively, in the first ON control, the U-phase second switching element 94U, the V-phase second switching element 94V, and the W-phase second switching element 94W may be turned on, and the U-phase first switching element 92U, the V-phase first switching element 92V, and the W-phase first switching element 92W may be turned off. When the first power converter 26 and the first motor generator 14 are three-phase, the first ON control corresponds to so-called three-phase ON control.

[0042] In the first ON control, a closed circuit is formed including the first switching element 92 and the winding 80 of the first motor generator 14, both in the ON state. Also, in the first ON control, the positive electrode 100 and the negative electrode 102 are substantially disconnected. As a result, when the first motor generator 14 rotates during the first ON control, the power generated by the first motor generator 14 is not regenerated to the battery 30, but instead flows back through the closed circuit including the first switching element 92 and the winding 80. This power is then converted into heat and consumed by the first motor generator 14 and other components.

[0043] When the first motor generator 14 rotates during the first ON control, a braking torque is generated on the output shaft of the first motor generator 14 due to the aforementioned recirculation, which acts to hinder the rotation of the first motor generator 14. The braking torque of the first motor generator 14 during the first ON control is sufficiently larger than the braking torque during the first OFF control.

[0044] Figure 3 shows an example of a collinear diagram based on the gear ratio of the planetary gear mechanism 10. The rotational speed of the sun gear 50 corresponds to the rotational speed of the first motor generator 14, the rotational speed of the carrier 56 corresponds to the rotational speed of the engine 12, and the rotational speed of the ring gear 52 corresponds to the rotational speed of the second motor generator 16 and the rotational speed of the axle 22. In the collinear diagram, the ratio of the distance between the vertical line of the sun gear 50 and the vertical line of the carrier 56, and the ratio of the distance between the vertical line of the carrier 56 and the vertical line of the ring gear 52, corresponds to the gear ratio.

[0045] As shown in Figure 3, the rotational speed of the first motor generator 14, the rotational speed of the engine 12, and the rotational speed of the second motor generator 16 (or axle 22) substantially satisfy the collinear relationship, where they lie on a common straight line.

[0046] When the rotational speed of engine 12 is increased, the torque of engine 12 (engine torque) increases. The torque of engine 12 is divided into the torque that rotates the first motor generator 14 and the torque that drives the axle 22 (drive torque), thereby rotating the first motor generator 14 and the axle 22.

[0047] As described above, when the first ON control is performed in the first power converter 26, a braking torque is generated in the first motor generator 14 in accordance with the rotation of the first motor generator 14. As a result, a first ON braking torque is generated in the engine 12, which is a braking torque that acts to hinder the rotation of the engine 12, due to the braking torque generated in the first motor generator 14. The first ON braking torque is obtained by converting the braking torque generated in the first motor generator 14 into a torque that acts on the engine 12 based on the gear ratio of the planetary mechanism 10.

[0048] Considering the gear ratio of the planetary mechanism 10, the amount of decrease in the rotational speed of the first motor generator 14 due to the braking torque generated in the first motor generator 14 is presumed to be greater than the amount of decrease in the rotational speed of the engine 12 due to the first on-braking torque acting on the engine 12. Therefore, it is possible to increase the rotational speed of the axle 22 by decreasing the rotational speed of the first motor generator 14.

[0049] Furthermore, for example, by increasing the torque of the engine 12 in order to suppress the decrease in the rotational speed of the engine 12 due to the first on-brake torque acting on the engine 12, it becomes possible to stably increase the rotational speed of the axle 22 by decreasing the rotational speed of the first motor generator 14.

[0050] Here, it is possible that both the first motor generator 14 and the second motor generator 16 may malfunction. For example, malfunctions in the first motor generator 14 and the second motor generator 16 may occur when the detection values ​​from both the first resolver 32 and the second resolver 34 become unobtainable.

[0051] If such an abnormality occurs, for example, the first power converter 26 can perform the first ON control described above, which enables the vehicle 1 to move to a safe location. As a result, even if the above-mentioned abnormality occurs, traffic safety can be ensured and the vehicle 1 can be transported to the repair shop.

[0052] However, if the engine speed 12 is relatively low, such as idling speed, when the first ON control is initiated, the engine 12 may stop due to the application of the first ON brake torque. In that case, for example, the driving force of vehicle 1 may suddenly disappear, making it impossible to properly move vehicle 1 to safety.

[0053] Therefore, in response to the detection of abnormalities in the first motor generator 14 and the second motor generator 16, the vehicle control unit 70 of the first embodiment derives an estimated value of the first on-brake torque assuming that the first on-control has been performed, before starting the first on-control. The vehicle control unit 70 substantially increases the torque of the engine 12 by the estimated value of the first on-brake torque, and then starts the first on-control.

[0054] Figure 4 is a flowchart showing an example of the operation flow of the vehicle control unit 70 in the first embodiment. If an abnormality is detected in both the first motor generator 14 and the second motor generator 16 (YES in S10), the vehicle control unit 70 executes the processing from step S11 onwards. For example, the vehicle control unit 70 may determine that an abnormality has been detected in both the first motor generator 14 and the second motor generator 16 if it is no longer possible to obtain detection values ​​from both the first resolver 32 and the second resolver 34.

[0055] If no abnormality is detected in either the first motor generator 14 or the second motor generator 16, or if an abnormality is detected in only one of the first motor generator 14 or the second motor generator 16 (NO in S10), the vehicle control unit 70 will not perform the series of processes shown in Figure 4, but will instead perform the normal processing.

[0056] In step S11, the vehicle control unit 70 acquires the detected values ​​from each sensor (S11). For example, the vehicle control unit 70 may acquire the actual rotational speed of the engine 12 detected by the engine rotational speed sensor 36. The vehicle control unit 70 may acquire the vehicle speed detected by the vehicle speed sensor 42. The vehicle control unit 70 may acquire the accelerator operation amount detected by the accelerator sensor 38. The vehicle control unit 70 may acquire the brake operation amount detected by the brake sensor 40.

[0057] The vehicle control unit 70 derives an estimated value of the first on-brake torque acting on the engine 12 based on the current vehicle speed, the current actual rotational speed of the engine 12, the gear ratio of the planetary gear 10, and the gear ratio of the reduction gear 18 (S12).

[0058] For example, the vehicle control unit 70 derives the current rotational speed of the second motor generator 16 (in other words, the rotational speed of the ring gear 52) based on the current vehicle speed and the gear ratio of the reduction gear 18. The vehicle control unit 70 derives the current rotational speed of the first motor generator 14 (in other words, the rotational speed of the sun gear 50) based on the current rotational speed of the second motor generator 16 (in other words, the rotational speed of the ring gear 52), the current actual rotational speed of the engine 12, and the gear ratio of the planetary mechanism 10. The vehicle control unit 70 derives an estimated value of the first on-brake torque acting on the engine 12 based on the rotational speed of the first motor generator 14 (in other words, the rotational speed of the sun gear 50) and the first on-brake torque table pre-stored in the memory 62.

[0059] Figure 5 shows an example of a first on-brake torque table. As shown in Figure 5, the first on-brake torque table is a table that associates the rotational speed of the first motor generator 14 with the first on-brake torque. The first on-brake torque is the brake torque that acts on the engine 12 due to the brake torque generated in the first motor generator 14 when the first on-control is performed on the first power converter 26. As shown in Figure 5, the first on-brake torque is expressed as an absolute value.

[0060] Figure 6 is a graph showing the relationship between the rotational speed of the first motor generator 14 and the first on-brake torque in the first on-brake torque table. As shown in Figure 6, the first on-brake torque is maximized when the rotational speed of the first motor generator 14 is relatively low, for example, about 250 rpm.

[0061] Note that the specific numerical values ​​in Figures 5 and 6 are not limited to those exemplified, and may be set to various values ​​depending on, for example, the specifications of the first motor generator 14, the gear ratio of the planetary gear 54, etc.

[0062] Let's return to Figure 4 for explanation. After step S12, the vehicle control unit 70 derives a first target torque that is greater than the current target torque of the engine 12 by the estimated value of the first on-brake torque (S13). For example, if the first on-brake torque is expressed as an absolute value, the vehicle control unit 70 derives the first target torque by adding the estimated value of the first on-brake torque derived in step S12 to the current target torque of the engine 12.

[0063] The vehicle control unit 70 derives a delay time, which is the estimated time required for the actual torque of the engine 12 at the present moment to reach the first target torque, assuming that a first target torque has been set as the target torque for the engine 12 at the present moment (S14).

[0064] For example, the vehicle control unit 70 derives a charging efficiency, which represents the amount of air contributing to combustion in the engine 12, based on the current accelerator input. The vehicle control unit 70 derives a delay time based on the current charging efficiency, the current actual rotational speed of the engine 12, and a delay time map pre-stored in the memory 62.

[0065] Figure 7 shows an example of a delay time map. As shown in Figure 7, the delay time map is a map that associates the charging efficiency of the engine 12, the rotational speed of the engine 12, and the delay time. In the delay time map, the delay time is set such that it increases as the charging efficiency of the engine 12 increases, and also increases as the rotational speed of the engine 12 increases.

[0066] Note that the specific numerical values ​​in Figure 7 are not limited to those exemplified; they may be set to various values ​​depending on, for example, the specifications of engine 12.

[0067] Let's return to Figure 4 for explanation. After step S14, the vehicle control unit 70 sets the first target torque derived in step S13 as the target torque for the engine 12 (S15). As a result, the actual torque of the engine 12 will increase to the first target torque derived in step S13.

[0068] The vehicle control unit 70 determines whether the delay time derived in step S14 has elapsed since the time when the first target torque was set as the target torque for the engine 12, that is, when step S15 was executed (S16). The vehicle control unit 70 waits until the delay time has elapsed (NO in S16).

[0069] If it is determined that the delay time has elapsed (YES in S16), the vehicle control unit 70 starts executing the first ON control for the first power converter 26 (S17).

[0070] The vehicle control unit 70 continues the first ON control until the termination condition for the first ON control is met (NO in S18 and S17). The termination condition for the first ON control may be, for example, when the vehicle 1 is turned off, or when an input operation indicating that the escape drive is completed is performed on a predetermined button on the vehicle 1.

[0071] If the vehicle control unit 70 determines that the termination condition for the first ON control has been met (YES in S18), it switches the first power converter 26 to the first OFF control (S19) and terminates the series of processes shown in Figure 4.

[0072] Thus, in the first embodiment, if an abnormality is detected in the first motor generator 14 and the second motor generator 16, the actual torque of the engine 12 is increased substantially by an estimated value of the first on-brake torque before the first on-control is started.

[0073] Therefore, in the vehicle 1 of the first embodiment, even if the first ON control is initiated, it is possible to avoid the engine 12 stopping due to the first ON control. As a result, in the vehicle 1 of the first embodiment, appropriate evasive driving can be performed in response to the detection of abnormalities in the first motor generator 14 and the second motor generator 16.

[0074] (Second Embodiment) Figure 8 is a diagram illustrating the control overview of vehicle 1A according to the second embodiment. The configuration of vehicle 1A in the second embodiment is substantially the same as that of vehicle 1 in the first embodiment. The operation of the vehicle control unit 70 in vehicle 1A in the second embodiment differs from that of vehicle 1 in the first embodiment. In the second embodiment, the differences from the first embodiment will be explained, and for convenience, the explanation of the points common to the first embodiment will be omitted.

[0075] In the second embodiment, similar to the first embodiment, the first ON control is performed on the first power converter 26 in response to the detection of an abnormality in the first motor generator 14 and the second motor generator 16. In this case, in the second embodiment, similar to the first embodiment, the torque of the engine 12 may be increased in advance before starting the first ON control, or, unlike the first embodiment, the first ON control may be started immediately without increasing the torque of the engine 12.

[0076] As described above, when the first ON control is performed, the first ON brake torque acts on the engine 12, causing the engine speed of the engine 12 to decrease. When the engine speed of the engine 12 decreases, there is a risk that the engine 12 will stop.

[0077] Therefore, in the second embodiment, the vehicle control unit 70 of the vehicle 1A performs intermittent control, which is a control that alternately repeats the first on control and the first off control in a pulse-like manner after the start of the first on control. That is, the vehicle control unit 70 of the vehicle 1A of the second embodiment repeatedly performs the first on control and the temporary release of the first on control in a short period of time.

[0078] In the lower part of Figure 8, the first ON state indicates that the first switching element 92 is ON, meaning that the first ON control is being executed. The first OFF state indicates that the first switching element 92 is OFF, meaning that the first ON control is temporarily released and the first OFF control is being executed.

[0079] As shown in the lower part of Figure 8, when the first ON control and the first OFF control are repeated alternately, the time during which the first ON control is effectively performed is shorter compared to the mode in which the first ON control is performed continuously.

[0080] Therefore, in the vehicle 1A of the second embodiment, even if the first ON control is started in response to the detection of an abnormality in the first motor generator 14 and the second motor generator 16, the amount of decrease in the rotational speed of the engine 12 can be suppressed. As a result, in the vehicle 1A of the second embodiment, it is possible to suppress the engine 12 from stopping.

[0081] Furthermore, the vehicle control unit 70 of the vehicle 1A in the second embodiment may control the duty cycle, which represents the ratio of the time of the first ON control to one cycle of the intermittent control, based on the engine speed difference, which represents the difference between the target rotational speed of the engine 12 and the actual rotational speed of the engine 12. More specifically, the vehicle control unit 70 may change the duty cycle based on the engine speed difference such that the duty cycle of the intermittent control decreases as the engine speed difference increases.

[0082] For example, in the lower part of Figure 8, the first ON control is initiated at approximately "1 ms," and intermittent control is performed thereafter. Once the first ON control is initiated, the rotational speed of the engine 12 decreases, as shown in the upper part of Figure 8 from approximately "2 ms" to "5 ms." As the rotational speed of the engine 12 decreases, the engine speed difference increases. Consequently, as shown in the middle part of Figure 8 from approximately "2 ms" to approximately "5 ms," the vehicle control unit 70 reduces the duty cycle in accordance with the increasing engine speed difference. This shortens the time during which the first ON control is effectively performed, and increases the amount of suppression of the decrease in the rotational speed of the engine 12.

[0083] Furthermore, as shown, for example, in the upper part of Figure 8 from approximately "5ms" to approximately "22ms", as the rotational speed of the engine 12 gradually recovers, the engine speed difference gradually decreases. Then, as shown in the middle part of Figure 8 from approximately "5ms" to approximately "22ms", the vehicle control unit 70 gradually increases the duty cycle in accordance with the decrease in the engine speed difference. As a result, the time during which the first ON control is substantially executed increases, and the amount of suppression of the decrease in the rotational speed of the engine 12 decreases.

[0084] Thus, in the vehicle 1A of the second embodiment, the amount of suppression of the decrease in engine speed 12 can be adjusted by changing the duty cycle based on the difference in engine speed. As a result, in the vehicle 1A of the second embodiment, the fluctuation of engine speed 12, in other words, the behavior of vehicle 1A, can be made smoother.

[0085] Furthermore, as shown in the middle section of Figure 8 at approximately "1 ms" to "2 ms", the vehicle control unit 70 may control the duty cycle to suppress, as much as possible, the rapid rise of the duty cycle to its maximum value immediately after the start of the first ON control.

[0086] Figure 9 is a flowchart showing an example of the operation flow of the vehicle control unit 70 in the second embodiment. If an abnormality is detected in both the first motor generator 14 and the second motor generator 16 (YES in S30), the vehicle control unit 70 executes the processing from step S31 onwards. For example, the vehicle control unit 70 may determine that an abnormality has been detected in both the first motor generator 14 and the second motor generator 16 if it is no longer possible to obtain detection values ​​for both the first resolver 32 and the second resolver 34.

[0087] If no abnormality is detected in either the first motor generator 14 or the second motor generator 16, or if an abnormality is detected in only one of the first motor generator 14 or the second motor generator 16 (NO in S30), the vehicle control unit 70 will not perform the series of processes shown in Figure 9, but will instead perform the normal processing.

[0088] In step S31, the vehicle control unit 70 starts the first ON control for the first power converter 26 (S31).

[0089] The vehicle control unit 70 acquires the detected values ​​from each sensor (S32). For example, the vehicle control unit 70 may acquire the actual rotational speed of the engine 12 detected by the engine rotational speed sensor 36. The vehicle control unit 70 may acquire the vehicle speed detected by the vehicle speed sensor 42. The vehicle control unit 70 may acquire the accelerator operation amount detected by the accelerator sensor 38. The vehicle control unit 70 may acquire the brake operation amount detected by the brake sensor 40.

[0090] The vehicle control unit 70 derives the current engine speed difference by subtracting the current actual engine speed of the engine 12 from the current target engine speed of the engine 12 (S33).

[0091] The vehicle control unit 70 determines the duty cycle in intermittent control based on the current engine speed difference (S34). For example, the vehicle control unit 70 derives the current driver's requested driving force based on the current accelerator operation and brake operation. The vehicle control unit 70 determines the duty cycle in intermittent control based on the current engine speed difference, the current driver's requested driving force, and the duty cycle map pre-stored in memory 62.

[0092] Figure 10 shows an example of a duty cycle map. As shown in Figure 10, the duty cycle map is a map that associates the engine speed difference, the driver's requested driving force, and the duty cycle in intermittent control. In the duty cycle map, the duty cycle is set such that the duty cycle decreases as the engine speed difference increases, and increases as the driver's requested driving force increases.

[0093] Let's return to Figure 9 for explanation. After step S34, the vehicle control unit 70 performs intermittent control according to the duty cycle determined in step S34 (S35). If the determined duty cycle is "100%", the intermittent control will be substantially the same as the first ON control.

[0094] The vehicle control unit 70 continues intermittent control until the termination condition for the first ON control is met (NO in S18 and S17). The termination condition for the first ON control may be, for example, when the vehicle 1A is turned off, or when an input operation indicating that the escape drive is completed is performed on a predetermined button on the vehicle 1A.

[0095] If the vehicle control unit 70 determines that the termination condition for the first ON control has been met (YES in S18), it switches the first power converter 26 to the first OFF control (S19) and terminates the series of processes shown in Figure 4.

[0096] (Third embodiment) Figure 11 is a flowchart showing an example of the operation flow of the vehicle control unit 70 of vehicle 1B according to the third embodiment. The configuration of vehicle 1B in the third embodiment is substantially the same as that of vehicle 1 in the first embodiment. The operation of the vehicle control unit 70 in vehicle 1B in the third embodiment differs from that of vehicle 1 in the first embodiment. In the third embodiment, the differences from the first embodiment will be explained, and for convenience, the explanation of the points that are common with the first embodiment will be omitted.

[0097] In the third embodiment, similar to the first embodiment, the first ON control is performed on the first power converter 26 in response to the detection of an abnormality in the first motor generator 14 and the second motor generator 16. In this case, in the third embodiment, similar to the first embodiment, the torque of the engine 12 may be increased in advance before starting the first ON control, or, unlike the first embodiment, the first ON control may be started immediately without increasing the torque of the engine 12.

[0098] Here, during the execution of the first ON control, the braking torque generated in the first motor generator 14 reaches its maximum value at a relatively low rotational speed close to "0 rpm". For the sake of explanation, the rotational speed at which the braking torque generated in the first motor generator 14 reaches its maximum value is sometimes referred to as the peak rotational speed.

[0099] As described above, once the first ON control is initiated and continues, the braking torque generated in the first motor generator 14 causes the rotational speed of the first motor generator 14 to gradually decrease. As a result, the rotational speed of the first motor generator 14 may reach its peak rotational speed. When the rotational speed of the first motor generator 14 is at its peak rotational speed, the driving force of the axle 22, which is in accordance with the fluctuations in the rotational speed of the first motor generator 14, reaches its maximum value.

[0100] However, when the rotational speed of the first motor generator 14 reaches its peak rotational speed, the actual rotational speed of the engine 12 will reach the target rotational speed (i.e., the rotational speed of the engine 12 at which the first motor generator 14 reaches its peak rotational speed). Therefore, once the rotational speed of the first motor generator 14 reaches its peak rotational speed, it is not possible to increase the driving force of the axle 22 thereafter. As a result, the acceleration of the vehicle 1B during the escape maneuver may be insufficient.

[0101] Therefore, in response to the start of the execution of the first ON control, the vehicle control unit 70 of the vehicle 1B of the third embodiment executes target rotation speed control, which controls the engine 12 so that the actual rotation speed of the engine 12 becomes the target rotation speed of the engine 12. If a predetermined switching condition is met during the execution of target rotation speed control, the vehicle control unit 70 of the vehicle 1B of the third embodiment switches to request output control, which controls the engine 12 so that the output of the engine 12 becomes a request output based on the accelerator operation amount.

[0102] The predetermined switching conditions described above are that the first motor generator rotational speed difference, which represents the difference between the actual rotational speed of the first motor generator 14 and the target rotational speed of the first motor generator 14, is less than or equal to a predetermined first threshold, and the engine rotational speed difference, which represents the difference between the target rotational speed of the engine 12 and the actual rotational speed of the engine 12, is less than or equal to a predetermined second threshold.

[0103] The predetermined first threshold may be set to a value that allows the difference in the rotational speed of the first motor generator to be determined to be substantially zero within the range of tolerance. The target rotational speed of the first motor generator 14 is set to, for example, the peak rotational speed. In this case, the condition that the difference in the rotational speed of the first motor generator is less than or equal to the first threshold is used to determine whether the actual rotational speed of the first motor generator 14 has substantially reached the target rotational speed of the first motor generator 14, in other words, the peak rotational speed.

[0104] The predetermined second threshold may be set to a value that allows the engine speed difference to be determined to be substantially zero within the allowable error range. The condition that the engine speed difference is less than or equal to the second threshold determines whether the actual rotational speed of engine 12 has not substantially decreased from the target rotational speed of engine 12. In other words, the condition that the engine speed difference is less than or equal to the second threshold determines whether engine 12 has stopped due to the first on-brake torque.

[0105] Thus, in the vehicle 1B of the third embodiment, the engine 12 is controlled by target rotational speed control from the time the first ON control is started until the switching condition is met.

[0106] As a result, in the vehicle 1B of the third embodiment, the driving force of the axle 22 can be appropriately increased according to the brake torque generated in the first motor generator 14 by the first ON control.

[0107] Furthermore, in the vehicle 1B of the third embodiment, when it is determined that the rotational speed of the first motor generator 14 has substantially reached its peak rotational speed and that the engine 12 has not stopped due to the first on-brake torque, the system switches from target rotational speed control to requested output control.

[0108] As a result, in the vehicle 1B of the third embodiment, even after the rotational speed of the first motor generator 14 has reached its peak rotational speed, the driving force of the axle 22 can be appropriately increased in accordance with the increase in torque of the engine 12 due to the requested output control.

[0109] As shown in Figure 11, if the vehicle control unit 70 of the third embodiment determines that the first ON control has started (YES in S50), it executes the processes from step S51 onwards. If it does not determine that the first ON control has started (NO in S50), the vehicle control unit 70 does not perform the series of processes shown in Figure 11, but instead performs the normal processing.

[0110] In step S51, the vehicle control unit 70 controls the engine 12 by target rotational speed control (S51).

[0111] The vehicle control unit 70 determines whether or not a predetermined switching condition for controlling the engine 12 is met (S52). If it determines that the switching condition is not met (NO in S52), the vehicle control unit 70 maintains target rotational speed control (S51). If it determines that the switching condition is met (YES in S52), the vehicle control unit 70 switches from target rotational speed control to requested output control and controls the engine 12 by the requested output control (S53).

[0112] In the processing of the switching condition in step S52, the vehicle control unit 70 first obtains the current actual rotational speed of the first motor generator 14 (S60). For example, the vehicle control unit 70 derives the current rotational speed of the second motor generator 16 (in other words, the rotational speed of the ring gear 52) based on the current vehicle speed and the gear ratio of the reduction gear 18. The vehicle control unit 70 derives the current rotational speed of the first motor generator 14 (in other words, the rotational speed of the sun gear 50) based on the current rotational speed of the second motor generator 16 (in other words, the rotational speed of the ring gear 52), the current actual rotational speed of the engine 12, and the gear ratio of the planetary mechanism 10. The vehicle control unit 70 treats the derived current rotational speed of the first motor generator 14 (in other words, the rotational speed of the sun gear 50) as the current actual rotational speed of the first motor generator 14.

[0113] The vehicle control unit 70 derives the current difference in the rotational speed of the first motor generator 14 by subtracting the current actual rotational speed of the first motor generator 14 from the current target rotational speed of the first motor generator 14 (S61).

[0114] The vehicle control unit 70 obtains the current actual rotational speed of the engine 12 based on the value detected by the engine rotational speed sensor 36 (S62).

[0115] The vehicle control unit 70 derives the current engine speed difference by subtracting the current actual engine speed of the engine 12 from the current target engine speed of the engine 12 (S63).

[0116] The vehicle control unit 70 determines whether the current difference in rotational speed of the first motor-generator is less than or equal to a predetermined first threshold (S64). If it is determined that the current difference in rotational speed of the first motor-generator is less than or equal to a predetermined first threshold (YES in S64), the vehicle control unit 70 determines whether the current difference in engine rotational speed is less than or equal to a predetermined second threshold (S65).

[0117] If it is determined that the current difference in rotational speed of the first motor-generator is less than or equal to a predetermined first threshold (YES in S64), and that the current difference in rotational speed of the engine is less than or equal to a predetermined second threshold (YES in S65), then the switching conditions are met, and the vehicle control unit 70 switches to requested output control (S53).

[0118] If the current difference in rotational speed of the first motor-generator is determined to be greater than a predetermined first threshold (NO in S64), or if the current difference in rotational speed of the engine is determined to be greater than a predetermined second threshold (NO in S65), the switching condition is not met, and the vehicle control unit 70 maintains the target rotational speed control (S51).

[0119] (Fourth Embodiment) Figure 12 is a flowchart showing an example of the operation flow of the vehicle control unit 70 of the vehicle 1C according to the fourth embodiment. The configuration of the vehicle 1C in the fourth embodiment is substantially the same as the configuration of the vehicle 1 in the first embodiment. The operation of the vehicle control unit 70 in the vehicle 1C of the fourth embodiment differs from that of the vehicle 1 in the first embodiment. In the fourth embodiment, the differences from the first embodiment will be explained, and for convenience, the explanation of the points that are common with the first embodiment will be omitted.

[0120] In the fourth embodiment, similar to the first embodiment, the first ON control is performed on the first power converter 26 in response to the detection of abnormalities in the first motor generator 14 and the second motor generator 16. In this case, in the fourth embodiment, similar to the first embodiment, the torque of the engine 12 may be increased in advance before starting the first ON control, or, unlike the first embodiment, the first ON control may be started immediately without increasing the torque of the engine 12.

[0121] As described in the third embodiment above, once the first ON control is started and continues, the rotational speed of the first motor generator 14 gradually decreases due to the braking torque generated in the first motor generator 14.

[0122] Here, when the rotational speed of the first motor generator 14 approaches its peak rotational speed, the first on-braking torque acts on the engine 12, causing the rotational speed of the engine 12 to fall below the rotational speed at which the engine 12 can be kept running, and the engine 12 may stop.

[0123] Therefore, in the vehicle 1C of the fourth embodiment, a first lower limit value, which is the lower limit of the rotational speed of the engine 12 when the first ON control is executed, is set in advance. The first lower limit value may be set to a value that is greater than the rotational speed at which the engine 12 mechanically stops, and close to the rotational speed at which the engine 12 mechanically stops. For example, the first lower limit value may be set to a value lower than the lower limit of the rotational speed of the engine 12 during normal idling (for example, 1000 rpm, etc.) (for example, 600 rpm, etc.).

[0124] In the fourth embodiment, the vehicle control unit 70 of the vehicle 1C derives a first target rotational speed of the engine 12 based on the rotational speed of the first motor generator 14 when the brake torque generated in the first motor generator 14 by the first ON control is at its maximum (i.e., the peak rotational speed). The peak rotational speed of the first motor generator 14 may be stored in advance in memory 62, for example.

[0125] In the fourth embodiment, if the vehicle control unit 70 of vehicle 1C is performing the first ON control and the first target rotational speed is greater than the first lower limit, it sets the first target rotational speed as the target rotational speed of the engine 12 and controls the engine 12. If the first target rotational speed is less than or equal to the first lower limit during the execution of the first ON control, the vehicle control unit 70 of vehicle 1C of the fourth embodiment sets the first lower limit as the target rotational speed of the engine 12 and controls the engine 12.

[0126] Thus, in the vehicle 1C of the fourth embodiment, if the first target rotational speed falls below the first lower limit, the target rotational speed of the engine 12 is limited to the first lower limit so as not to fall below the first lower limit.

[0127] As a result, in the vehicle 1C of the fourth embodiment, it is possible to prevent the engine 12 from mechanically stopping due to the target rotational speed of the engine 12 falling below the first lower limit.

[0128] In the fourth embodiment, the vehicle control unit 70 may perform the series of processes shown in Figure 12 at predetermined intervals after detecting an abnormality in the first motor generator 14 and the second motor generator 16. As shown in Figure 12, the vehicle control unit 70 determines whether or not the first ON control is being performed on the first power converter 26 (S70). If it is determined that the first ON control is not being performed (NO in S70), the vehicle control unit 70 terminates the series of processes shown in Figure 12.

[0129] If it is determined that the first ON control is in operation (YES in S70), the vehicle control unit 70 acquires the detected values ​​from each sensor (S71). For example, the vehicle control unit 70 may acquire the vehicle speed detected by the vehicle speed sensor 42.

[0130] The vehicle control unit 70 derives a first target rotational speed for the engine 12 based on the current vehicle speed and the peak rotational speed of the first motor generator 14 (S72). For example, the vehicle control unit 70 derives the current rotational speed of the second motor generator 16 (in other words, the rotational speed of the ring gear 52) based on the current vehicle speed and the gear ratio of the reduction gear 18. The vehicle control unit 70 derives the rotational speed of the engine 12 (in other words, the rotational speed of the carrier 56) as the first target rotational speed for the engine 12 based on the current rotational speed of the second motor generator 16 (in other words, the rotational speed of the ring gear 52), the peak rotational speed of the first motor generator 14, and the gear ratio of the planetary mechanism 10.

[0131] The vehicle control unit 70 determines whether the current first target rotational speed of the engine 12, derived in step S72, is greater than a preset first lower limit (S73).

[0132] If the vehicle control unit 70 determines that the current first target rotational speed of engine 12 is greater than the first lower limit (YES in S73), it sets the current first target rotational speed of engine 12 as the target rotational speed of engine 12 (S74). Then, the vehicle control unit 70 controls engine 12 according to the set target rotational speed (i.e., the current first target rotational speed of engine 12) (S75).

[0133] On the other hand, if the vehicle control unit 70 determines that the current first target rotational speed of the engine 12 is below the first lower limit (YES in S73), the vehicle control unit 70 sets the first lower limit as the target rotational speed of the engine 12 (S76). Then, the vehicle control unit 70 controls the engine 12 according to the set target rotational speed (i.e., the first lower limit) (S75).

[0134] (Fifth embodiment) Figure 13 is a flowchart showing an example of the operation flow of the vehicle control unit 70 of the vehicle 1D according to the fifth embodiment. The configuration of the vehicle 1D in the fifth embodiment is substantially the same as the configuration of the vehicle 1 in the first embodiment. The operation of the vehicle control unit 70 in the vehicle 1D in the fifth embodiment differs from that of the vehicle 1 in the first embodiment. In the fifth embodiment, the differences from the first embodiment will be explained, and for convenience, the explanation of the points that are common with the first embodiment will be omitted.

[0135] In the fifth embodiment, similar to the first embodiment, the first ON control is performed on the first power converter 26 in response to the detection of abnormalities in the first motor generator 14 and the second motor generator 16. In this case, in the fifth embodiment, similar to the first embodiment, the torque of the engine 12 may be increased in advance before starting the first ON control, or, unlike the first embodiment, the first ON control may be started immediately without increasing the torque of the engine 12.

[0136] As described above, when the first ON control is performed, the first ON brake torque is applied to the engine 12. Also, as described above, if the first ON control continues and the above switching conditions are met, the vehicle control unit 70 may control the engine 12 by requested driving force control.

[0137] Here, for example, depending on the driver's requested driving force, the required torque of the engine 12 derived based on the driver's requested driving force may be greater than the first on-brake torque acting on the engine 12. In this case, the actual torque of the engine 12 will increase, and as a result, the rotational speed of the first motor generator 14 may increase against the brake torque generated in the first motor generator 14. If this happens, for example, the rotational speed of the first motor generator 14 may change in a direction away from the peak rotational speed, and as a result, the driving force of the axle 22 may decrease.

[0138] Therefore, in the fifth embodiment, the vehicle control unit 70 of the vehicle 1D maintains the current required torque of the engine 12 if the required torque of the engine 12 is less than the current first on-brake torque, and sets the current first on-brake torque as the required torque of the engine 12 if the required torque of the engine 12 is equal to or greater than the current first on-brake torque.

[0139] As a result, in the vehicle 1D of the fifth embodiment, the required torque of the engine 12 is suppressed to be less than or equal to the first on-brake torque. Therefore, in the vehicle 1D of the fifth embodiment, it is possible to suppress an increase in the rotational speed of the first motor generator 14, and as a result, it is possible to suppress a decrease in the driving force of the axle 22.

[0140] Furthermore, as described above, when the first ON control is performed, the power generated by the first motor generator 14 is not regenerated into the battery 30, but is instead consumed as heat in the first motor generator 14 and other components. As a result, the temperature of the first motor generator 14 may rise while the first ON control is being performed.

[0141] If the vehicle control unit 70 detects that the temperature of the first motor generator 14 has risen excessively, it may switch from first ON control to first OFF control to protect the first motor generator 14.

[0142] However, if the first ON control is suddenly released, the driving force of the axle 22 will change abruptly, which may hinder the vehicle's ability to move in the siding position.

[0143] Therefore, the vehicle control unit 70 of the vehicle 1D of the fifth embodiment derives a first required torque for the engine 12 based on the accelerator operation amount. The vehicle control unit 70 of the vehicle 1D of the fifth embodiment determines a first upper limit value, which is the upper limit value of the torque of the engine 12, based on the temperature of the first motor generator 14, such that the first upper limit value decreases as the temperature of the first motor generator 14 increases. During the execution of the first ON control, if the first required torque is less than the first upper limit value, the vehicle control unit 70 of the vehicle 1D of the fifth embodiment sets the first required torque as the required torque for the engine 12, and if the first required torque is equal to or greater than the first upper limit value, it sets the first upper limit value as the required torque for the engine 12 and controls the engine 12.

[0144] As a result, in the vehicle 1D of the fifth embodiment, the required torque of the engine 12 can be reduced as the temperature of the first motor generator 14 increases. When the required torque of the engine 12 decreases, the driving force of the axle 22 also decreases. Therefore, even if the temperature of the first motor generator 14 rises excessively and the first ON control is suddenly released, in the vehicle 1D of the fifth embodiment, the amount of change in the driving force of the axle 22 can be suppressed because the driving force of the axle 22 has already decreased. As a result, the impact on evasive driving can be suppressed in the vehicle 1D of the fifth embodiment.

[0145] In the fifth embodiment, the vehicle control unit 70 may perform the series of processes shown in Figure 13 at predetermined intervals after detecting an abnormality in the first motor generator 14 and the second motor generator 16. As shown in Figure 13, the vehicle control unit 70 determines whether or not the first ON control is being performed on the first power converter 26 (S90). If it is determined that the first ON control is not being performed (NO in S90), the vehicle control unit 70 terminates the series of processes shown in Figure 12.

[0146] If the vehicle control unit 70 determines that the first ON control is in operation (YES in S90), it acquires the detected values ​​from each sensor (S91). For example, the vehicle control unit 70 may acquire the actual rotational speed of the engine 12 detected by the engine rotational speed sensor 36. The vehicle control unit 70 may acquire the vehicle speed detected by the vehicle speed sensor 42. The vehicle control unit 70 may acquire the accelerator operation amount detected by the accelerator sensor 38. The vehicle control unit 70 may acquire the brake operation amount detected by the brake sensor 40. The vehicle control unit 70 may acquire the temperature of the first motor generator 14 detected by the temperature sensor 46.

[0147] The vehicle control unit 70 derives the current driver's requested driving force based on the current accelerator operation amount and the current brake operation amount, and derives the first requested torque for the engine 12 based on the current driver's requested driving force and the gear ratio of the planetary mechanism 10 (S91).

[0148] The vehicle control unit 70 determines a first upper limit value for the torque of the engine 12 based on the current temperature of the first motor generator 14 (S93). For example, the vehicle control unit 70 determines the first upper limit value based on the current temperature of the first motor generator 14 and a pre-stored first upper limit value table.

[0149] Figure 14 shows an example of the first upper limit table. As shown in Figure 14, the first upper limit table is a table that associates the temperature of the first motor generator 14 with the first upper limit of the torque of the engine 12. In the first upper limit table, the first upper limit is set to decrease as the temperature of the first motor generator rises.

[0150] Let's return to Figure 13 for explanation. After step S93, the vehicle control unit 70 determines whether the current first required torque derived in step S92 is less than the current first upper limit determined in step S93 (S94).

[0151] If the vehicle control unit 70 determines that the current first required torque is less than the current first upper limit (YES in S94), it sets the current first required torque as the required torque for the engine 12 (S95) and proceeds to step S97.

[0152] If the vehicle control unit 70 determines that the current first requested torque is equal to or greater than the current first upper limit (NO in S94), it sets the current first upper limit as the requested torque for the engine 12 (S96) and proceeds to step S97.

[0153] In step S97, the vehicle control unit 70 derives the current first on-brake torque (S97). For example, the vehicle control unit 70 derives the current rotational speed of the second motor generator 16 (in other words, the rotational speed of the ring gear 52) based on the current vehicle speed and the gear ratio of the reduction gear 18. The vehicle control unit 70 derives the current rotational speed of the first motor generator 14 (in other words, the rotational speed of the sun gear 50) based on the current rotational speed of the second motor generator 16 (in other words, the rotational speed of the ring gear 52), the current actual rotational speed of the engine 12, and the gear ratio of the planetary mechanism 10. The vehicle control unit 70 derives the current first on-brake torque acting on the engine 12 based on the rotational speed of the first motor generator 14 (in other words, the rotational speed of the sun gear 50) and the first on-brake torque table (see Figure 5) pre-stored in the memory 62.

[0154] The vehicle control unit 70 determines whether the requested torque determined in step S95 or step S96 is less than the current first on-brake torque (S98).

[0155] If the vehicle control unit 70 determines that the required torque determined in step S95 or step S96 is less than the current first on-brake torque (YES in S98), it maintains the required torque determined in step S95 or step S96 (S99) and proceeds to the process in step S101.

[0156] If the vehicle control unit 70 determines that the requested torque determined in step S95 or step S96 is greater than or equal to the current first on-brake torque (NO in S98), the vehicle control unit 70 sets the current first on-brake torque as the requested torque for the engine 12 (S100) and proceeds to the process in step S101.

[0157] In step S101, the vehicle control unit 70 controls the engine 12 according to the requested torque set in step S99 or step S100 (S101).

[0158] (Sixth Embodiment) Figure 15 is a flowchart showing an example of the operation flow of the vehicle control unit 70 of the vehicle 1E according to the sixth embodiment. The configuration of the vehicle 1E in the sixth embodiment is substantially the same as the configuration of the vehicle 1 in the first embodiment. The operation of the vehicle control unit 70 in the vehicle 1E in the sixth embodiment differs from that of the vehicle 1 in the first embodiment. In the sixth embodiment, the differences from the first embodiment will be explained, and for convenience, the explanation of the points that are common with the first embodiment will be omitted.

[0159] In the sixth embodiment, similar to the first embodiment, the first ON control is performed on the first power converter 26 in response to the detection of abnormalities in the first motor generator 14 and the second motor generator 16. In this case, in the sixth embodiment, similar to the first embodiment, the torque of the engine 12 may be increased in advance before starting the first ON control, or, unlike the first embodiment, the first ON control may be started immediately without increasing the torque of the engine 12.

[0160] As described above, when the first ON control is performed, the power generated by the first motor generator 14 is consumed as heat in the first motor generator 14 and other components, and is not regenerated into the battery 30. For this reason, the battery 30 cannot be charged while the first ON control is in operation, and the State of Charge (SOC) of the battery 30 may decrease. SOC is an indicator that represents the charge rate or charge state of the battery 30.

[0161] Therefore, while abnormalities are detected in the first motor generator 14 and the second motor generator 16, the vehicle control unit 70 of the sixth embodiment derives the current driver's requested driving force based on the current accelerator operation amount and brake operation amount. Based on the combination of the current driver's driving force and the current SOC of the battery 30, the vehicle control unit 70 of the sixth embodiment selects one of the first on control and the first off control and executes the selected one.

[0162] For example, if the State of Charge (SOC) of the battery 30 is relatively high, the vehicle control unit 70 may select and execute the first ON control in accordance with the operation of pressing the accelerator pedal.

[0163] As a result, in the vehicle 1E of the sixth embodiment, the first ON control can transmit appropriate driving force to the axle 22, and as a result, it is possible to perform retraction driving appropriately.

[0164] Furthermore, for example, the vehicle control unit 70 may, even if the battery's SOC is relatively high, release the first ON control and execute the first OFF control when the brake pedal is operated.

[0165] Furthermore, even if the accelerator pedal is operated, the vehicle control unit 70 may release the first ON control and execute the first OFF control if the battery's SOC is relatively low.

[0166] As a result, in the vehicle 1E of the sixth embodiment, charging of the battery 30 becomes possible by releasing the first ON control and executing the first OFF control, thereby suppressing the decrease in SOC. Consequently, in the vehicle 1E of the sixth embodiment, it is possible to prevent the vehicle 1E from becoming inoperable due to the SOC falling below the lower limit.

[0167] In the sixth embodiment, the vehicle control unit 70 may perform the series of processes shown in Figure 15 at predetermined intervals after detecting an abnormality in the first motor generator 14 and the second motor generator 16.

[0168] As shown in Figure 15, the vehicle control unit 70 obtains the current accelerator operation amount from the value detected by the accelerator sensor 38 and the current brake operation amount from the value detected by the brake sensor 40 (S111).

[0169] The vehicle control unit 70 derives the driver's requested driving force at the current time based on the current accelerator operation amount and the current brake operation amount (S112).

[0170] The vehicle control unit 70 obtains the current State of Charge (SOC) by, for example, estimating the SOC based on the detected value of the voltage sensor 44 (S113).

[0171] The vehicle control unit 70 selects one of the first ON control and the first OFF control based on the current driver's requested driving force derived in step S112 and the current SOC obtained in step S113 (S114). For example, the vehicle control unit 70 may select one of the first ON control and the first OFF control based on the current driver's requested driving force, the current SOC, and a selection map pre-stored in memory 62.

[0172] Figure 16 shows an example of a selection map. In Figure 16, "A" indicates that the first off control is selected, and "B" indicates that the first on control is selected. Also, regarding the driver's requested driving force in Figure 16, a positive value is the requested driving force in the acceleration direction, and a negative value is the requested driving force in the deceleration direction.

[0173] As shown in Figure 16, the selection map is a map that associates the State of Control (SOC), the driver's required driving force, and which of the first ON control and the first OFF control is selected. In the selection map, as the SOC increases, the first ON control "B" is more likely to be selected, and as the driver's required driving force increases, the first ON control "B" is more likely to be selected. In other words, in the selection map, as the SOC decreases, the first OFF control "A" is more likely to be selected, and as the driver's required driving force decreases, the first OFF control "A" is more likely to be selected.

[0174] Let's return to Figure 15 for explanation. The vehicle control unit 70 executes the one selected in step S114 from the first ON control and the first OFF control (S115).

[0175] Embodiments of the present invention have been described above with reference to the attached drawings, but it goes without saying that the present invention is not limited to these embodiments. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention.

[0176] For example, the features of each of the above embodiments may be combined as appropriate.

[0177] Furthermore, the processes described herein do not necessarily have to be performed chronologically in the order shown in the flowchart; they may include parallel processing or processing using subroutines. [Explanation of symbols]

[0178] Vehicles 1, 1A, 1B, 1C, 1D, 1E 10 Planetary Mechanisms 12 Engines 14. First Motor Generator 16. Second Motor Generator 22 axles 26. First Power Converter 30 batteries 48 Control device 50 Sun Gear 52 Ring Gear 54 Planetary Gear 56 Careers 60 processors 62 memory 80, 80U, 80V, 80W winding 90, 90U, 90V, 90W Arm 92, 92U, 92V, 92W First switching element 94, 94U, 94V, 94W Second switching element 100 Positive electrode wire 102 Negative electrode wire 104U, 104V, 104W connection point

Claims

1. A planetary gear mechanism having a sun gear, a ring gear, planetary gears, and a carrier that rotatably supports the planetary gears, The engine connected to the aforementioned carrier, A first motor generator connected to the sun gear, The ring gear and the second motor generator connected to the axle, A first power converter electrically connected to the first motor generator, Control device and Equipped with, The first power converter includes a plurality of arms connected in parallel, Each of the plurality of arms includes a first switching element and a second switching element connected in series between a positive electrode wire and a negative electrode wire. The connection point between the first switching element and the second switching element is connected to the winding of the first motor generator. The control device is One or more processors, One or more memories connected to the processor, It has, The first ON control is a control that causes one of the first switching element and the second switching element in the plurality of arms to be turned ON in common, and the other of the first switching element and the second switching element in the plurality of arms to be turned OFF in common. The brake torque acting on the engine due to the brake torque generated in the first motor generator when the first ON control is performed is the first ON brake torque. The aforementioned processor, In response to the detection of abnormalities in the first motor generator and the second motor generator, an estimated value of the first on-brake torque acting on the engine is derived, assuming that the first on-control is performed at this time. To derive a first target torque that is greater than the current target torque of the engine by the estimated value of the first on-brake torque, Assuming that the first target torque is set as the target torque for the engine at this point in time, the delay time is estimated to be the time required for the actual torque of the engine at this point in time to reach the first target torque. Setting the first target torque as the target torque for the engine, The execution of the first ON control is started after the delay time has elapsed from the time the first target torque is set as the target torque of the engine, A vehicle that performs a process that includes the following.

2. The control that turns off all of the first and second switching elements of the plurality of arms is the first off control. The aforementioned processor, After the start of the first ON control, intermittent control is performed, which is a control that alternately repeats the first ON control and the first OFF control in a pulse-like manner. Execute the process that includes The vehicle according to claim 1.

3. The aforementioned processor, The duty cycle is changed based on the engine speed difference, such that as the engine speed difference, which represents the difference between the target engine speed and the actual engine speed, increases, the duty cycle, which represents the ratio of the time of the first ON control to one cycle of the intermittent control, decreases. Execute the process that includes The vehicle according to claim 2.

4. The aforementioned processor, In response to the start of the execution of the first ON control, target rotational speed control is performed to control the engine so that the actual rotational speed of the engine becomes the target rotational speed of the engine, If a predetermined switching condition is met during the execution of the target rotational speed control, the system switches to a request output control that controls the engine so that the engine output becomes a request output based on the accelerator pedal input. Execute the process that includes, The switching conditions are that the first motor generator rotational speed difference, which represents the difference between the actual rotational speed of the first motor generator and the target rotational speed of the first motor generator, is less than or equal to a predetermined first threshold, and the engine rotational speed difference, which represents the difference between the target rotational speed of the engine and the actual rotational speed of the engine, is less than or equal to a predetermined second threshold. The vehicle according to claim 1.

5. A first lower limit value, which is the lower limit of the engine speed when the first ON control is executed, is set in advance. The aforementioned processor, Based on the rotational speed of the first motor generator at which the brake torque generated in the first motor generator by the first ON control is maximized, the first target rotational speed of the engine is derived. During the execution of the first ON control, if the first target rotational speed is greater than the first lower limit, the first target rotational speed is set as the target rotational speed of the engine; if the first target rotational speed is less than or equal to the first lower limit, the first lower limit is set as the target rotational speed of the engine, and the engine is controlled accordingly. Execute the process that includes The vehicle according to claim 1.

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