JP2010188800A - Control device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the control device of a hybrid vehicle for increasing such situations that an EV traveling state is executable while properly protecting a battery. <P>SOLUTION: In the control device of a hybrid vehicle which is configured by connecting an engine Eng, a motor for power generation (first motor generator MG1), and a motor for driving (second motor generator MG2) to the rotation element of a planetary gear mechanism TM, and connecting the motor for driving (MG2) to a driving wheel, and electrically connecting a battery 4 to the motor for power generation (MG1) and the motor for driving (MG2), and provided with an engine start control means (flow chart in Fig.5) for starting the engine Eng by generating cranking torque by the motor for power generation (MG1), when the vehicle speed of the vehicle is fast, the engine start control means makes cranking torque to be generated by the motor for power generation (MG1) smaller than that when the vehicle speed is slow. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for a hybrid vehicle in which an engine, a power generation motor, and a drive motor are coupled to a rotating element of a planetary gear mechanism.

  Conventionally, in a hybrid vehicle in which a power generation motor that can generate power using the power of the engine and a drive motor that can transmit power to the axle are connected via a planetary gear mechanism, the EV travels only by the drive motor. There is known a control device for a hybrid vehicle including an engine start control means for starting an engine by generating a cranking torque by a power generation motor when shifting from a traveling state to a HEV traveling state in which the engine is also driven. (For example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 9-308812

  By the way, in the above-described hybrid vehicle, when cranking is performed using the power generation motor, depending on the vehicle speed, power is generated by the power generation motor by generating cranking torque by the power generation motor. It grows according to the size of. The electric power generated by the power generation motor is input to the battery and charged. Since the allowable charging amount is set for the battery from the viewpoint of protection, the conventional hybrid vehicle control device does not exceed the allowable charging amount of the battery when power is input from the power generation motor. In addition, an upper limit value of the vehicle speed is set in the EV running state, and the engine is started when the upper limit value is reached. For this reason, there are fewer situations where the EV running state can be executed, more situations where the engine is driven in a state of low efficiency, and the effect of improving fuel efficiency is reduced.

  The present invention has been made paying attention to the above problem, and an object of the present invention is to provide a control device for a hybrid vehicle that can increase the number of situations in which the EV running state can be executed while appropriately protecting the battery.

  In order to achieve the above object, in the hybrid vehicle control device of the present invention, the engine, the power generation motor, and the drive motor are coupled to the rotating element of the planetary gear mechanism, and the drive motor is coupled to the drive wheels. The motor and the drive motor are electrically connected to the battery, and include engine start control means for starting the engine by generating cranking torque by the power generation motor. The engine start control means reduces the cranking torque generated by the power generation motor when the vehicle speed is high compared to when the vehicle speed is low.

  Therefore, in the hybrid vehicle control device of the present invention, when the vehicle speed is high, the power generation amount (electric power amount) by the power generation motor can be reduced along with the reduction of the cranking torque. However, when cranking the engine, the power supplied to the battery can be reduced to reduce the load when the battery is charged. For this reason, since the vehicle speed which starts cranking can be made high, the condition which can perform EV driving | running | working state can be increased.

1 is an overall system diagram illustrating a hybrid vehicle (an example of a hybrid vehicle) to which a control device according to a first embodiment is applied. FIG. 4 is an explanatory diagram for explaining characteristics of a hybrid vehicle to which the control device of the first embodiment is applied, in which (a) is a driving force performance characteristic diagram and (b) is a driving force conceptual diagram. FIG. 3 is a contrast characteristic diagram showing braking force performance by regenerative cooperation in a hybrid vehicle to which the control device of Example 1 is applied, (a) is a general braking force characteristic diagram, and (b) is a control characteristic of Example 1. FIG. It is a collinear diagram which shows each vehicle mode in the hybrid vehicle to which the control apparatus of Example 1 was applied, (a) shows a stop mode, (b) shows a start mode, (c) shows an engine start mode. (D) shows a steady travel mode, and (e) shows an acceleration mode. FIG. 6 is a flowchart showing details of engine start control processing executed by an integrated controller 6 in travel control in “EV mode”. It is a control block diagram which shows the engine starting control process in the integrated controller 6. It is an alignment chart for explanation of "technical problem", (a) shows the running state in the "EV mode", (b) engine start control (cranking operation) from (a) Indicates the state. FIG. 3 is a graph showing the relationship between the power generation amount and cranking torque by the first motor generator MG1 (generator) with respect to the vehicle speed for the explanation of the operation in the vehicle control apparatus of the first embodiment, and FIG. (B) shows the relationship of Example 1.

  Hereinafter, the best mode for realizing a control device for a hybrid vehicle of the present invention will be described based on a first embodiment shown in the drawings.

  First, the configuration will be described.

  FIG. 1 is an overall system diagram illustrating a hybrid vehicle (an example of a hybrid vehicle) to which the control device of the first embodiment is applied. 2A and 2B are explanatory diagrams for explaining the characteristics of the hybrid vehicle to which the control device of the first embodiment is applied. FIG. 2A is a driving force performance characteristic diagram, and FIG. 2B is a driving force conceptual diagram. . FIG. 3 is a contrast characteristic diagram showing a braking force performance by regenerative cooperation in a hybrid vehicle to which the control device of the first embodiment is applied. FIG. 3A is a general braking force characteristic diagram, and FIG. 6 is a braking force characteristic diagram of Example 1. FIG. FIG. 4 is an alignment chart showing vehicle modes in a hybrid vehicle to which the control device of the first embodiment is applied. (A) shows a stop mode, (b) shows a start mode, and (c) shows a start mode. An engine start mode is shown, (d) shows a steady running mode, and (e) shows an acceleration mode. The configuration of the drive system of the hybrid vehicle will be described below with reference to FIGS.

  As shown in FIG. 1, the drive system of the hybrid vehicle in the first embodiment includes an engine Eng, a first motor generator MG1 (power generation motor (hereinafter also referred to as a generator)), and a second motor generator MG2 (drive motor). (Hereinafter also simply referred to as a motor)), an output sprocket OS, and a power split mechanism TM (planetary gear mechanism).

  The engine Eng is a gasoline engine or a diesel engine, and the opening degree of the throttle valve and the like are controlled based on a control command from an engine controller 1 described later.

  The first motor generator MG1 and the second motor generator MG2 are synchronous motor generators in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator. Based on a control command from a motor controller 2 described later, Each is controlled independently by applying a three-phase alternating current generated by the power control unit 3.

  Both the motor generators MG1 and MG2 can operate as electric motors that are driven to rotate by receiving electric power from the battery 4 (hereinafter, this state is referred to as “power running” or “discharge”), and the rotor has an external force. , The battery 4 can be charged by functioning as a generator that generates electromotive force at both ends of the stator coil (hereinafter, this state is referred to as “regeneration” or “power generation”).

  The power split mechanism TM is configured by a simple planetary gear having a sun gear S, a pinion P, a ring gear R, and a pinion carrier PC. The connection relationship of the input / output members with respect to the three rotating elements (sun gear S, ring gear R, and pinion carrier PC) of the simple planetary gear will be described. The sun gear S is connected to a first motor generator MG1. A second motor generator MG2 and an output sprocket OS are connected to the ring gear R. An engine Eng is connected to the pinion carrier PC via an engine damper ED. The output sprocket OS is connected to the left and right front wheels via a chain belt CB, a differential and a drive shaft (not shown).

  Due to the above connection relationship, the first motor generator MG1 (sun gear S), the engine Eng (pinion carrier PC), the second motor generator MG2 and the output sprocket OS (ring gear R) are arranged in this order on the alignment chart shown in FIG. Thus, it is possible to introduce a rigid lever model (a relationship in which three rotational speeds are always connected by a straight line) that can simply express the dynamic operation of a simple planetary gear.

  Here, the “collinear diagram” is a velocity diagram used in a simple and easy-to-understand method of drawing instead of the method of obtaining by equation when considering the gear ratio of the differential gear. Take the number of rotations (rotation speed) of each rotating element, take each rotating element on the horizontal axis, and determine the spacing between each rotating element based on the gear ratio λ of sun gear S and ring gear R: (S ~ PC): (PC ~ The length ratio of R) is arranged to be 1: λ.

  Next, the control system of the hybrid vehicle will be described.

  As shown in FIG. 1, the control system of the hybrid vehicle in the first embodiment includes an engine controller 1, a motor controller 2, a power control unit 3 (high power unit), a battery 4 (secondary battery), and a brake controller 5. And an integrated controller 6.

  The integrated controller 6 includes an accelerator opening sensor 7, a vehicle speed sensor 8, an engine speed sensor 9, a first motor generator speed sensor 10, a second motor generator speed sensor 11, and a shift position sensor 27. And the battery temperature sensor 28 provides input information. The vehicle speed sensor 8 and the second motor generator rotation speed sensor 11 are for detecting the output rotation speed of the same power split mechanism TM, so the vehicle speed sensor 8 is omitted and the second motor generator rotation speed sensor 11 The sensor signal may be used as a vehicle speed signal.

  The brake controller 5 includes a front left wheel speed sensor 12, a front right wheel speed sensor 13, a rear left wheel speed sensor 14, a rear right wheel speed sensor 15, a steering angle sensor 16, and a master cylinder pressure sensor 17. The brake stroke sensor 18 provides input information.

  The engine controller 1 responds to an engine operating point (Ne) according to a target engine torque command or the like from an integrated controller 6 that inputs an accelerator opening Acc from an accelerator opening sensor 7 and an engine speed Ne from an engine speed sensor 9. , Te), for example, is output to a throttle valve actuator (not shown).

  The motor controller 2 includes a first motor generator MG1 (generator) rotational speed Ng from the first motor generator rotational speed sensor 10 by the resolver and a second motor generator MG2 (motor from the second motor generator rotational speed sensor 11 by the resolver. ), The motor operating point (Ng, T1) of the first motor generator MG1 and the motor operating point of the second motor generator MG2 (Nm, T2) is output to the power control unit 3 to control each of them independently. The motor controller 2 uses information on the battery SOC that represents the state of charge of the battery 4.

  The power control unit 3 constitutes a high-power unit with a high-voltage power supply system that can supply power to both motor generators MG1 and MG2 with less current, and includes a joint box, a boost converter, a drive motor inverter, And a generator generator inverter and a capacitor. A drive motor inverter is connected to the stator coil of the second motor generator MG2. A generator generator inverter is connected to the stator coil of the first motor generator MG1. The joint box is connected to a battery 4 that is discharged during power running and charged during regeneration. The power control unit 3 monitors the battery SOC indicating the charge capacity of the battery 4 and supplies this information to the integrated controller 6. Further, the power control unit 3 independently drives the first motor generator MG1 and the second motor generator MG2 with a torque or a rotational speed corresponding to a command from the motor controller 2.

  The brake controller 5 performs ABS control according to a control command to a brake hydraulic pressure unit 19 that independently controls the brake hydraulic pressure of the four wheels during low-μ road braking, sudden braking, and the like. At the time of braking by the brake, regenerative brake cooperative control is performed by issuing a control command to the integrated controller 6 and a control command to the brake hydraulic pressure unit 19. The brake controller 5 includes wheel speed information from the wheel speed sensors 12, 13, 14, 15, steering angle information from the steering angle sensor 16, braking operation from the master cylinder pressure sensor 17 and the brake stroke sensor 18. Quantity information is entered. And based on these input information, a predetermined calculation process is performed and the control command by the process result is output to the integrated controller 6 and the brake hydraulic pressure unit 19. FIG. A front left wheel wheel cylinder 20, a front right wheel wheel cylinder 21, a rear left wheel wheel cylinder 22, and a rear right wheel wheel cylinder 23 are connected to the brake fluid pressure unit 19.

  The integrated controller 6 manages the energy consumption of the entire vehicle and has a function for running the vehicle with the highest efficiency. The integrated controller 6 performs engine operating point control by a control command to the engine controller 1 during acceleration running. In addition, the motor generator operating point control is performed by a control command to the motor controller 2 at the time of stopping, running, braking, or the like. The integrated controller 6 includes an accelerator opening Acc, a vehicle speed V, an engine speed Ne, a first motor-generator speed Ng, and a second motor-generator speed Nm from the sensors 7, 8, 9, 10, and 11. Entered. And based on these input information, a predetermined calculation process is performed and the control command by the process result is output to the engine controller 1 and the motor controller 2. FIG. The integrated controller 6 and the engine controller 1, the integrated controller 6 and the motor controller 2, and the integrated controller 6 and the brake controller 5 are connected by bidirectional communication lines 24, 25, and 26, respectively, for information exchange.

  Next, driving force performance will be described.

  As shown in FIG. 2B, the driving force of the hybrid vehicle of the first embodiment is the engine direct driving force (the driving force obtained by subtracting the driving force for driving the first motor generator MG1 from the total engine driving force). It is shown as the sum of the motor driving force (the driving force by the sum of both motor generators MG1, MG2). As shown in FIG. 2A, the maximum driving force is configured such that the lower the vehicle speed, the greater the motor driving force. In this way, it has no transmission and runs by adding the direct drive force of the engine Eng and the motor drive force converted electrically, so that the full power of the accelerator pedal is fully opened from low power to high speed from low to high speed. Until now, it is possible to control the driving force seamlessly with good response to the driver's required driving force (torque on demand).

  In the hybrid vehicle of the first embodiment, the engine Eng, both motor generators MG1, MG2, and the left and right front wheels (drive wheels) are connected without a clutch via the power split mechanism TM. Further, as described above, most of the engine power is converted into electric energy by a generator, and the vehicle is driven by a motor with high output and high response. For this reason, for example, when driving on slippery roads such as an ice burn, when the driving force of the vehicle changes suddenly due to slipping of driving wheels or locking of driving wheels during braking, the power control unit 3 from excessive current It is necessary to protect the parts from the pinion over rotation of the power split mechanism TM. On the other hand, utilizing the characteristics of high-output and high-response motors, we have developed from a component protection function, which detects the driving slip of the driving wheel instantly, recovers its grip, and makes the vehicle run safely. Adopt control.

  Next, the braking force performance will be described.

  In the hybrid vehicle of the first embodiment, the kinetic energy of the vehicle is converted into electric energy by operating the second motor generator MG2 operating as a motor as a generator (generator) during braking by an engine brake or a foot brake. Then, a regenerative braking system that recovers and reuses the battery 4 is adopted.

  As shown in FIG. 3A, the general regenerative brake cooperative control in this regenerative brake system calculates the required braking force with respect to the brake pedal depression amount, and is calculated regardless of the magnitude of the required braking force. The required braking force is shared by the regenerative component and the hydraulic component.

  On the other hand, in the regenerative brake cooperative control adopted in the hybrid vehicle of the first embodiment, as shown in FIG. 3B, the required braking force is calculated with respect to the brake pedal depression amount, and the calculated required braking force is calculated. On the other hand, the regenerative brake is given priority, and as long as the regenerative portion can cover it, the regenerative portion is expanded to the maximum without using the hydraulic component. Thereby, especially in a traveling pattern in which acceleration / deceleration is repeated, energy recovery efficiency is high, and energy recovery by regenerative braking is realized up to a lower vehicle speed.

  Next, the vehicle mode will be described.

  As the vehicle mode in the hybrid vehicle of the first embodiment, as shown in the alignment chart of FIG. 4, “stop mode”, “start mode”, “engine start mode”, “steady travel mode”, “acceleration mode” Have

  In the “stop mode”, as shown in FIG. 4A, the engine Eng, the first motor generator MG1, and the second motor generator MG2 are stopped. In the “start mode”, as shown in FIG. 4B, the vehicle starts by driving only the second motor generator MG2. Hereinafter, traveling by driving only the second motor generator MG2 in this manner is referred to as traveling in the “EV mode”. In the “engine start mode”, as shown in FIG. 4C, the first gear generator (generator) MG1 having a function as an engine starter rotates the sun gear S to start the engine Eng. In the “steady running mode”, as shown in FIG. 4D, the vehicle runs mainly with the engine Eng, and power generation is minimized in order to increase efficiency. In the “acceleration mode”, as shown in FIG. 4 (e), the engine Eng is increased in rotation speed, and power generation by the first motor generator MG <b> 1 is started. Add driving force of MG2 and accelerate. In reverse running, in the “steady running mode” shown in FIG. 4D, if the rotation speed of the first motor generator MG1 is increased while the increase in the rotation speed of the engine Eng is suppressed, the rotation of the second motor generator MG2 is performed. The number shifts to the negative side and reverse travel can be achieved.

  When starting, the engine Eng is started by turning the ignition key, and immediately after the engine Eng is warmed up, the engine Eng stops. When starting or at a light load, when starting or when going down a gentle hill running at a very low speed, the fuel is cut in areas where engine efficiency is low, and the engine Eng is stopped and the vehicle is driven by the second motor generator MG2. . During normal travel, the driving force of the engine Eng is driven directly by the power split mechanism TM, one of which directly drives the wheel, the other drives the first motor generator (generator) MG1, and assists the second motor generator MG2. At the time of full open acceleration, power is supplied from the battery 4 and further driving force is added. At the time of deceleration or braking, the wheel drives the second motor generator MG2, and acts as a generator to perform regenerative power generation. The collected electrical energy is stored in the battery 4. When the charge amount of the battery 4 decreases, the first motor generator (generator) MG1 is driven by the engine Eng to start charging. When the vehicle is stopped, the engine Eng is automatically stopped except when the air conditioner is used or when the battery is charged.

  FIG. 5 is a flowchart showing the engine start control process executed by the integrated controller 6 in the travel control in the “EV mode”. That is, the flowchart of FIG. 5 serves as engine start control means. FIG. 6 is a control block diagram showing an engine start control process in the integrated controller 6. Hereafter, each step of the flowchart of FIG. 5 is demonstrated using FIG.

  In step S1, the state of charge of battery 4 (SOC [%]) and the temperature of battery 4 (Tbatt [° C.]) are read, and the process proceeds to step S2.

  In step S2, following the reading of the state of charge SOC and battery temperature Tbatt in step S1, the battery maximum input allowable value Win [W] at the time of determination that is the allowable charge amount is calculated, and the process proceeds to step S3. In step S2, the charge allowable amount calculation unit 31 calculates the battery maximum input allowable value Win [W] from the charge state SOC and the battery temperature Tbatt using the battery maximum input map (Fwin). This battery maximum input map (Fwin) shows the relationship between the battery maximum input allowable value Win and the battery temperature Tbatt corresponding to the state of charge SOC in the battery 4.

  In step S3, following the calculation of the battery maximum input allowable value Win [W] in step S2, the EV limited vehicle speed Vevmx [km / h] is calculated, and the process proceeds to step S4. In step S3, the EV limit vehicle speed calculation unit 32 calculates the EV limit vehicle speed Vevmx from the battery maximum input allowable value Win calculated in step S2 using the EV limit vehicle speed map (Fvevmx). The EV limit vehicle speed map (Fvevmx) shows the relationship of the EV limit vehicle speed Vevmx with respect to the battery maximum input allowable value Win. The characteristic line of the EV limit vehicle speed Vevmx indicates the maximum electric energy that can be input to the battery 4 in the situation where the cranking operation is performed during coast regeneration when the electric energy input to the battery 4 is the largest in the “EV mode”, that is, 2 shows the relationship of the vehicle speed with respect to the sum of the power generation amount (power amount) by coast regeneration in the two motor generator MG2 and the power generation amount (power amount) by cranking in the first motor generator MG1.

  In step S4, following the calculation of the EV limited vehicle speed Vevmx [km / h] in step S3, the engine speed En [rad / sec] at the time of determination is read, and the process proceeds to step S5.

  In step S5, following the reading of the rotational speed Ne [rad / sec] of the engine Eng in step S4, the conventional cranking torque Tgbs [Nm] is calculated, and the process proceeds to step S6. In step S5, the conventional cranking torque calculator 33 calculates the conventional cranking torque Tgbs [Nm] from the rotational speed Ne of the engine Eng read in step S4 using the cranking torque table (Ftgbs). This cranking torque table (Ftgbs) shows the relationship of cranking torque to the rotational speed Ne of the engine Eng, which is preset based on requirements such as engine start shock and acceleration response.

  In step S6, following the calculation of the conventional cranking torque Tgbs [Nm] in step S5, the vehicle speed (actual vehicle speed) V [km / h] at the time of determination is read, and the process proceeds to step S7.

  In step S7, following reading of the actual vehicle speed V [km / h] in step S6, other engine start request flags Flg are read, and the process proceeds to step S8. With respect to the other engine start request flag Flg, it is determined that it is necessary to charge the battery 4 due to the state of charge (SOC) of the battery 4 or the engine torque output from the engine Eng is necessary. Refers to cases.

  In step S8, following the reading of the other engine start request flag Flg in step S7, the accelerator opening Acc [%] and the shift lever position SFT are read, and the process proceeds to step S9.

  In step S9, following the reading of the accelerator opening Acc [%] and the shift lever position SFT in step S8, the regeneration torque Tr [Nm] is calculated, and the process proceeds to step S10. In step S9, the regenerative torque calculator 34 calculates the regenerative torque Tr [Nm] from the actual vehicle speed, the accelerator opening Acc and the shift lever position SFT read in step S8, using the drive torque map (Fdrv). This drive torque map (Fdrv) is set for each shift lever position SFT, that is, for each gear position, and shows the relationship of the drive torque to the vehicle speed according to the accelerator opening Acc.

  In step S10, following the calculation of the regenerative torque Tr [Nm] in step S9, the rotational speed Nm [rad / sec] of the second motor generator MG2 (motor) is read, and the process proceeds to step S11.

  In step S11, following the reading of the rotational speed Nm [rad / sec] in step S10, the power generation amount by regeneration (regenerative power generation amount) Pr [W] is calculated, and the process proceeds to step S12. The regenerative power generation amount Pr [W] is a power generation amount by coast regeneration based on the state of the second motor generator MG2 at the time of determination. In step S11, the regenerative power generation amount calculation unit 35 multiplies the regenerative torque Tr [Nm] calculated in step S9 by the rotation speed Nm [rad / sec] of the second motor generator MG2 read in step S10. The regenerative power generation amount Pr [W] is calculated (regenerative power generation amount Pr [W] = (regenerative torque Tr [Nm]) × (rotational speed Nm [rad / sec])).

  In step S12, following the calculation of the regenerative power generation amount Pr [W] in step S11, the cranking available power Pgevmx [W] is calculated, and the process proceeds to step S13. The cranking available power Pgevmx [W] is used to generate a power generation allowable amount (power amount) by cranking based on the state of the battery 4 and the second motor generator MG2 at the time of determination, that is, cranking torque. This is the amount of power that can be used by the first motor generator MG1 (generator). In step S12, the available power calculator 36 subtracts the regenerative power generation amount Pr [W] calculated in step S11 from the battery maximum input allowable value Win calculated in step S2, thereby allowing the cranking available power Pgevmx [W ] (Cranking available power Pgevmx [W] = (battery maximum input allowable value Win [W]) − (regenerative power generation amount Pr [W])).

  In step S13, following the calculation of the cranking available power Pgevmx [W] in step S12, the rotation speed Ng [rad / sec] of the first motor generator MG1 (generator) is read, and the process proceeds to step S14.

  In step S14, following the reading of the rotational speed Ng [rad / sec] in step S13, the cranking available torque Tgevmx [Nm] is calculated, and the process proceeds to step S15. The cranking usable torque Tgevmx [Nm] is a value that can be generated by the first motor generator MG1 for the cranking operation based on the state of the battery 4, the second motor generator MG2, and the first motor generator MG1 at the time of determination. This is the maximum value of the cranking torque, that is, the maximum value of the cranking torque based on the amount of electric power available in the first motor generator MG1 (generator). In step S14, the number of revolutions Ng [rad / sec] of the first motor generator MG1 at the time of determination in which the available torque calculation unit 37 reads the cranking available power Pgevmx [W] calculated in step S12 in step S13. The cranking available torque Tgevmx [Nm] is calculated by dividing by (cranking available torque Tgevmx [Nm] = (cranking available power Pgevmx [W]) / (rotational speed Ng [rad / sec] )).

  In step S15, following the calculation of the cranking available torque Tgevmx [Nm], it is determined whether or not the engine start condition (cranking execution condition) is satisfied. If yes, the process proceeds to step S16. If no, Proceed to step S19. In step S15, the starting condition determination unit 38 determines that the actual vehicle speed V is greater than the EV limit vehicle speed Vevmx calculated in step S3 and the cranking usable torque Tgevmx [Nm] calculated in step S14 is the lower limit cranking torque range Tgmn. Or when the other engine start request flag Flg read in step S7 is in the ON state (other engine start request is present), it is determined that the engine start condition is satisfied. The lower limit cranking torque range Tgmn is for making the cranking torque as close as possible to the lower limit value at which the cranking operation can be completed. A lower limit value) and a value obtained by adding a predetermined value to the lower limit value. This lower limit cranking torque range Tgmn is a range that can reliably prevent the cranking operation from being performed while enabling the cranking operation to start at a value as close as possible to the lower limit value at which the cranking operation can be completed. Is set in

  In step S16, following the determination that the engine start condition is satisfied in step S15, in the generator torque command setting unit 39, the cranking torque calculated in step S14 can be used for the conventional cranking torque Tgbs [Nm] calculated in step S5. It is determined whether or not the torque is greater than Tgevmx [Nm]. If Yes, the process proceeds to Step S17, and if No, the process proceeds to Step S18.

  In step S17, following the determination that the conventional cranking torque Tgbs [Nm] is larger than the cranking available torque Tgevmx [Nm] in step S16, the generator torque command setting unit 39 uses the cranking available torque Tgevmx [Nm]. ] Is adopted as the generator command torque Tg (command to the first motor generator MG1). In step S17, a torque command value that causes the first motor generator MG1 to generate a cranking usable torque Tgevmx [Nm] as a cranking torque for the cranking operation of the engine Eng is output to the power control unit 3. Thereafter, engine start control is executed, and a transition is made to travel control in another mode (engine start control process is terminated).

  In step S18, following the determination that the conventional cranking torque Tgbs [Nm] in step S16 is smaller than the cranking available torque Tgevmx [Nm], the generator torque command setting unit 39 uses the conventional cranking torque Tgbs [Nm]. Is adopted as the generator command torque Tg (command to the first motor generator MG1). In step S18, a torque command value for causing the first motor generator MG1 to generate the conventional cranking torque Tgbs [Nm] as the cranking torque for the cranking operation of the engine Eng is output to the power control unit 3. Thereafter, engine start control is executed, and a transition is made to travel control in another mode (engine start control process is terminated). That is, in Step S16, Step S17 and Step S18, the generator torque command setting unit 39 uses the smaller of the cranking available torque Tgevmx [Nm] and the conventional cranking torque Tgbs [Nm] as the generator (first motor). Generator MG1) Set as command torque Tg.

  In step S19, following the determination that the engine start condition is not satisfied in step S15, the generator torque command setting unit 39 sets the generator (first motor generator MG1) command torque Tg to 0, that is, engine start (cranking operation). Without returning to step S1.

  Next, the operation will be described.

  FIG. 7 is a collinear diagram for explaining the “technical problem”, in which (a) shows a traveling state in “EV mode”, and (b) shows engine start control (cranking operation) from (a). ) Is shown. FIG. 8 is a graph showing the relationship between the power generation amount and the cranking torque by the first motor generator MG1 (generator) with respect to the vehicle speed for the purpose of explaining the operation in the vehicle control apparatus of the first embodiment. (B) shows the relationship of Example 1. FIG. In FIG. 8, on the vertical axis, the upper side from the 0 position is the amount of power generation, and the lower side is the cranking torque. Hereinafter, the “technical problem” will be described first, and then “the operation of the vehicle control device of the first embodiment” will be described.

"Technical challenges"
In the hybrid vehicle of the first embodiment, as described above, in the traveling state in the “EV mode” (“start mode”), as shown in FIG. 7A, the first connected to the left and right front wheels (drive wheels). Only the 2-motor generator MG2 (motor) generates drive / regenerative torque. At this time, the engine Eng is kept stationary by its own friction. Further, the first motor generator MG1 (generator) is driven idle by the second motor generator MG2 and rotates in the negative direction (hereinafter referred to as negative rotation), but is in an idling state in which no torque is generated.

  In this state, when the cranking operation is performed to start the engine Eng, as shown in FIG. 7B, the torque (cranking torque) for increasing the rotational speed of the engine Eng is set to the first motor generator MG1 (generator). To generate.

  Here, in the first motor generator MG1 (generator) and the second motor generator MG2 (motor), discharge (power running) occurs when the direction of rotation and the direction of action of the generated torque match, and power generation (regeneration) occurs when they do not match. It becomes. Further, the amount of power generation is the product of the rotational speed and the torque. Furthermore, since the second motor generator MG2 (motor) is connected to the left and right front wheels (drive wheels), the rotation speed is proportional to the vehicle speed.

  Therefore, in order to generate cranking torque in the first motor generator MG1 (generator) to start the engine Eng when traveling in the “EV mode”, the negative rotation side is operated in the positive rotation side. Therefore, the first motor generator MG1 (generator) generates power when cranking torque is generated. When the engine Eng is stopped, the rotation speed (negative rotation) of the first motor generator MG1 (generator) is higher than that of the second motor generator MG2 (motor) as shown in FIG. Therefore, it increases in proportion to the increase in vehicle speed. Therefore, when the first motor generator MG1 (generator) is running in the “EV mode” and the cranking torque is generated by the first motor generator MG1 (generator) to start the engine Eng, the vehicle speed is increased. The higher the value, the larger the power generation.

  Further, when starting the engine Eng during traveling in the “EV mode”, if the driver turns off the accelerator (releases his / her foot), the second motor generator MG2 (motor) will perform coast regeneration, so the battery 4 Is the sum of the power generation amount (power amount) by cranking in the first motor generator MG1 and the power generation amount (power amount) by coast regeneration in the second motor generator MG2. Here, when the vehicle speed is high, the power generation amount (power amount) due to the coast regeneration in the second motor generator MG2 and the power generation amount (power amount) due to the cranking in the first motor generator MG1 increase, and the battery 4 The maximum amount of power that can be input to becomes larger.

  For this reason, if the driver turns off the accelerator when the engine Eng is started when traveling in the “EV mode”, the power from the coast regeneration and the power from the cranking are input to the battery 4, so that the battery There is a possibility that the charge allowable amount set from the viewpoint of protection of 4 is exceeded. For this reason, in the conventional hybrid vehicle control device, in the travel in the “EV mode”, the upper limit value of the vehicle speed is set, and the engine Eng is started when the actual vehicle speed exceeds the upper limit value. Electric power exceeding the allowable amount is prevented from being input to the battery 4.

  However, as described above, in the engine start determination based on the actual vehicle speed with respect to the set upper limit value of the vehicle speed, the engine Eng is started even though there is a margin in the actual charge allowance of the battery 4. The situation where the vehicle can be run in the “EV mode” is reduced. This is because the upper limit value of the vehicle speed described above takes into account various possibilities in the state of the first motor generator MG1 and the second motor generator MG2, and the power generation amount (electric power amount) by coast regeneration at the second motor generator MG2. This is because the power generation amount (power amount) by cranking in the first motor generator MG1 is calculated and set based on this. As a result, the number of situations in which the engine Eng is driven in a state of low thermal efficiency increases, and the effect of improving fuel efficiency is reduced. For this reason, it is necessary to increase the situation in which traveling in the “EV mode” can be executed while ensuring protection of the battery 4 by some measures.

“Operation in the vehicle control apparatus of the first embodiment”
In the hybrid vehicle control device according to the present invention, based on the state of the battery 4 at the time of determination, the state of the second motor generator MG2 at the time of determination, and the state of the first motor generator MG1 at the time of determination. By setting the cranking torque generated by the first motor generator MG1, the engine Eng is started in conformity with the actual charge allowable amount of the battery 4.

  That is, in the travel in the “EV mode”, the maximum battery input of the battery 4 at the time of determination is made in the flow chart of FIG. Permissible value Win [W] (step S2), EV limit vehicle speed Vevmx [km / h] (step S3) for battery maximum input allowable value Win, and engine Eng speed Ne [rad / sec] at the time of judgment The conventional cranking torque Tgbs [Nm] (step S4) and the presence / absence of another engine start request flag Flg (step S7) are acquired. In the conventional engine start determination, it is determined that the actual vehicle speed V [km / h] is higher than the EV limit vehicle speed Vevmx [km / h] at this time, or that the other engine start request flag Flg is ON. By determining, the engine Eng is started with the conventional cranking torque Tgbs [Nm]. Therefore, if the other engine start request flag Flg is OFF (0), the actual vehicle speed V [km / h] becomes the EV limited vehicle speed Vevmx [km / h] as shown in FIG. Since the engine Eng is started at this point, the engine Eng is considered in view of the actual charge allowable amount of the battery 4 while considering the actual state of the first motor generator MG1 and the second motor generator MG2. There is a possibility that the situation of starting will occur.

  On the other hand, in the hybrid vehicle control apparatus of the first embodiment, the second motor generator at the time of determination is further advanced by proceeding from step S8 → step S9 → step S10 → step S11 → step S12 → step S13 → step S14. Regenerative power generation amount Pr [W] (step S8, step S9, step S10 and step S11) that can be generated by coast regeneration based on the state of MG2, and the state based on the state of battery 4 and second motor generator MG2 at the time of determination The cranking available power Pgevmx [W] (step S12), which is the allowable power generation amount (power amount) by ranking, and the state of the battery 4, the second motor generator MG2, and the first motor generator MG1 at the time of determination. Cranking, which is the maximum cranking torque that can be generated by the first motor generator MG1 for ranking operation, can be used Noh torque Tgevmx [Nm] (step S14). Then, proceeding to step S15, in addition to the actual vehicle speed V [km / h] being greater than the EV limit vehicle speed Vevmx [km / h], the cranking available torque Tgevmx [Nm] is the lower limit cranking torque range. If it is determined that Tgmn has been reached, it is determined that the engine start condition (cranking execution condition) has been satisfied, and the process proceeds from step S16 to step S17 or step S18, where cranking available torque Tgevmx [Nm] and conventional cranking are determined. The smaller of the torques Tgbs [Nm] is set as the generator (first motor generator MG1) command torque Tg.

  As described above, in addition to the actual vehicle speed V [km / h] being higher than the EV limit vehicle speed Vevmx [km / h], the cranking available torque Tgevmx [Nm] is now within the lower cranking torque range Tgmn. By determining, it is determined that the engine start condition (cranking execution condition) is satisfied, and the smaller one of the cranking available torque Tgevmx [Nm] and the conventional cranking torque Tgbs [Nm] is determined as the generator (first Since the motor generator MG1) is set as the command torque Tg, the amount of power available to the first motor generator MG1 (generator) based on the state of the battery 4 and the state of the second motor generator MG2 at the time of determination is determined. Using the cranking torque that can be actually generated by the first motor generator MG1, calculated from the rotational speed of the first motor generator MG1 at the time, It is possible to start the cranking operation with a cranking torque close to the lower limit value at which the cranking operation can be completed while allowing the engine Eng to start reliably. it can.

  For this reason, as shown in FIG. 8 (b), the first motor is compared with starting the engine Eng when the actual vehicle speed V [km / h] becomes the EV limited vehicle speed Vevmx [km / h]. The cranking torque generated by the generator MG1 can be reduced. In addition, since the amount of electric power (electric power) generated by coast regeneration at the second motor generator MG2 can be reduced along with the reduction of the cranking torque, the amount of reduction can be reduced by the second motor generator as the vehicle speed increases or the regeneration torque increases. Charging of the battery 4 is possible because it can be used as an increase in power generation (electric power) due to coast regeneration in MG2 and as power generation (electric power) due to cranking in the first motor generator MG1 as the vehicle speed increases. Even if the vehicle speed is higher than the EV limit vehicle speed Vevmx [km / h] within a range not exceeding the allowable value, it is possible to travel in the “EV mode”. For this reason, it is possible to increase the number of situations in which the traveling in the “EV mode” can be executed while ensuring the protection of the battery 4. The improvement effect can be made larger.

  Next, the effect will be described.

  In the hybrid vehicle control device of the first embodiment, the following effects can be obtained.

  (1) The engine Eng, the power generation motor (first motor generator MG1), and the drive motor (second motor generator MG2) are connected to the rotating elements of the planetary gear mechanism TM, and the drive motor is connected to the drive wheels. The engine 4 is electrically connected to the power generation motor and the drive motor, and the engine is started by generating cranking torque by the power generation motor (flowchart in FIG. 5). In the control apparatus for a hybrid vehicle, the engine start control means reduces the cranking torque generated by the power generation motor when the vehicle speed is high compared to when the vehicle speed is low. For this reason, it is possible to increase the number of situations in which the EV running state can be executed while appropriately protecting the battery 4.

  (2) The drive system includes an engine Eng, a power generation motor (first motor generator MG1), and a drive motor (second motor generator MG2) coupled to a rotating element of the planetary gear mechanism TM. In a control apparatus for a hybrid vehicle, the battery 4 is electrically connected to the drive motor, and engine start control means (flowchart in FIG. 5) for starting the engine by generating cranking torque by the power generation motor. The engine start control means can be used for cranking calculated from the amount of power that can be used by the drive motor based on the state of the battery and the state of the power generation motor, and the state of the drive motor. When the torque reaches a lower limit value at which the cranking operation can be completed, the engine is started.

  Therefore, the cranking operation can be started with a cranking torque close to the lower limit value at which the cranking operation can be completed while the engine Eng can be reliably started, and the EV running state while appropriately protecting the battery 4 Can increase the number of situations that can be executed.

  As mentioned above, although the vehicle control apparatus of the present invention has been described based on the first embodiment, the specific configuration is not limited to these embodiments, and the invention according to each claim of the claims is described. Design changes and additions are allowed without departing from the gist.

  In the first embodiment, an example of application to a hybrid vehicle by front wheel drive provided with one engine, two motor generators, and a power split mechanism has been shown. In short, an engine, a power generation motor, and a drive are used as rotating elements of a planetary gear mechanism. The present invention can be applied to any hybrid vehicle in which a motor for use is connected.

4 Battery 1 Engine controller (as engine start control means) 2 Motor controller (as engine start control means) 3 Power control unit (as engine start control means) 4 Battery 6 Integrated controller
Eng engine
TM Power split mechanism (as planetary gear mechanism)
MG1 First motor generator (as a motor for power generation)
MG2 Second motor generator (as drive motor)

Claims (2)

An engine, a power generation motor, and a drive motor are connected to the rotating element of the planetary gear mechanism, the drive motor is connected to a drive wheel, and a battery is electrically connected to the power generation motor and the drive motor. And a hybrid vehicle control device comprising engine start control means for starting the engine by generating cranking torque by the power generation motor,
The engine start control means reduces the cranking torque generated by the power generation motor when the vehicle speed is high compared to when the vehicle speed is low. In the drive system, an engine, a power generation motor, and a drive motor are coupled to a rotating element of the planetary gear mechanism, and a battery is electrically connected to the power generation motor and the drive motor. In a hybrid vehicle control device comprising engine start control means for starting the engine by generating ranking torque,
The engine start control means is a torque that can be used for cranking calculated from the amount of electric power that can be used by the drive motor based on the state of the battery and the state of the power generation motor, and the state of the drive motor. However, the control device for a hybrid vehicle starts the engine when a lower limit value at which the cranking operation can be completed is reached.

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