JP2012166676A - Vehicle and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve driving force control corresponding to the road surface by controlling erroneous determination of the road surface.SOLUTION: ECU executes a program that includes: a step (S102) that executes a band pass filter processing; a step (S104) that executes an integrated value calculation processing; a step (S106) that executes a low-pass filter processing; a step (S114) that determines whether the difference of the second filter output value this time and the second filter output value last time is a threshold value α or more for each predetermined time; a step (S116) that adds 1 to an increase count value Ci when the difference of the second filter output value this time and the second filter output value last time is a threshold value α or more (YES in S114); and a step (S124) that executes the restriction control of the driving force when the second filter output value Fo2 is β or more and the increase count value Ci is γ or more (YES in S122).

Description

  The present invention relates to control of driving force of a vehicle in which an internal combustion engine and driving wheels are mechanically coupled.

  When the vehicle is traveling on a rough road such as a wavy road, rotational fluctuations occur in the drive wheels, and resonance may occur in the drive system including components from the power source to the drive wheels. In order to protect parts from excessive input due to the generated resonance, for example, Japanese Unexamined Patent Application Publication No. 2009-040174 (Patent Document 1) discloses a technique for reducing the driving force of a vehicle in accordance with road surface unevenness. .

JP 2009-040174 A

  However, if it is erroneously determined when resonance is detected and it is determined whether or not the road surface of the vehicle is a rough road, there arises a problem that the driving force of the vehicle is reduced when the vehicle is not traveling on a bad road. . The above-mentioned publication does not consider such a problem at all, and there is room for improvement in suppressing erroneous determination.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a vehicle and a vehicle control method that suppresses erroneous determination of a traveling road surface and realizes driving force control according to the traveling road surface. Is to provide.

  A vehicle according to an aspect of the present invention includes a drive system including a drive wheel for generating a drive force in the vehicle, an internal combustion engine, and a drive transmission device for mechanically connecting the internal combustion engine and the drive wheel; A detection unit for detecting a rotation speed of at least one of the driving wheel and a part that rotates in conjunction with the rotation of the driving wheel, and a driving force is controlled based on the rotation speed detected by the detection unit. And a control unit. When the magnitude of the fluctuation component of the rotational speed is greater than the first threshold value and the value indicating the increasing tendency of the integrated value is greater than the second threshold value, the control unit drives Limit power.

  Preferably, after the driving force is limited, the control unit drives based on the magnitude of the fluctuation component when the magnitude of the fluctuation component is smaller than a third threshold value equal to or less than the first threshold value. The force return rate is determined, and the driving force restriction is released according to the determined return rate.

  More preferably, each of the first threshold value and the second threshold value is a value for determining that resonance has occurred due to a rough road traveling of the vehicle in the drive system. The control unit extracts a fluctuation component in the resonance frequency band of the rotation speed in a predetermined period before the current time point, and calculates the magnitude of the fluctuation component based on the extracted fluctuation component.

  More preferably, the control unit calculates the number of times that the amount of change in the magnitude of the fluctuation component in the predetermined period becomes larger than the fourth threshold value as a value indicating an increasing tendency.

  More preferably, the drive transmission device includes a drive shaft for rotating the drive wheels, a first rotating electrical machine, a second rotating electrical machine provided on the driving shaft, a drive shaft, an output shaft of the internal combustion engine, and the first rotating electrical machine. A power transmission device capable of transmitting power between the other two elements by mechanically connecting each of the three elements of the rotating shaft of the motor, and using any one of the three elements as a reaction force element; including.

  A vehicle control method according to another aspect of the present invention includes a drive system including a drive wheel for generating a drive force, an internal combustion engine, and a drive transmission device for mechanically connecting the internal combustion engine and the drive wheel. It is the control method for vehicles used for the vehicle which mounts. In this vehicle control method, the step of detecting the rotational speed of at least one of the drive wheels and the parts that rotate in conjunction with the rotation of the drive wheels and the magnitude of the fluctuation component of the rotational speed are the first. And a step of limiting the driving force of the vehicle when the value indicating the increasing tendency of the magnitude of the fluctuation component is larger than the second threshold value.

  According to the present invention, even when a vibration occurs in the drive system and the magnitude of the fluctuation component of the resonance frequency band temporarily increases, as long as the value indicating the increase tendency does not exceed the threshold value, the drive force is limited. Can be suppressed. Therefore, erroneous determination that the vehicle is traveling on a rough road can be suppressed. In addition, when it is determined that the vehicle is traveling on a rough road, the driving force limiting control is executed to protect the components of the driving system. Therefore, it is possible to provide a vehicle and a vehicle control method that can suppress erroneous determination of the traveling road surface and realize driving force control according to the traveling road surface.

1 is an overall block diagram of a vehicle according to an embodiment. It is a functional block diagram of ECU mounted in the vehicle which concerns on this Embodiment. It is FIG. (1) for demonstrating the detection method of the resonance of a drive system. FIG. 6 is a (second) diagram for explaining a resonance detection method of the drive system. It is a flowchart which shows the control structure of the program which restricts a driving force according to the 2nd filter output value performed with ECU mounted in the vehicle which concerns on this Embodiment. It is a flowchart which shows the control structure of the program which cancels | releases the restriction | limiting of a driving force according to the 2nd filter output value performed with ECU mounted in the vehicle which concerns on this Embodiment. It is a timing chart (the 1) for explaining operation of ECU mounted in vehicles concerning this embodiment. It is a timing chart (2) for demonstrating operation | movement of ECU mounted in the vehicle which concerns on this Embodiment. It is a timing chart (the 3) for demonstrating operation | movement of ECU mounted in the vehicle which concerns on this Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  With reference to FIG. 1, an overall block diagram of a vehicle 1 according to the present embodiment will be described. Vehicle 1 includes a PCU (Power Control Unit) 60, a main battery 70, a drive system 84, and an ECU (Electronic Control Unit) 200. The drive system 84 includes an engine 10, a first motor generator (hereinafter referred to as a first MG) 20, a second motor generator (hereinafter referred to as a second MG) 30, drive wheels 80, and a transmission 86. Including. The transmission 86 is a drive force transmission device that includes the drive shaft 16, the power split device 40, the speed reducer 58, and the drive shaft 82.

  The vehicle 1 travels with driving force output from at least one of the engine 10 and the second MG 30. The power generated by the engine 10 is divided into two paths by the power split device 40. One of the two routes is a route transmitted to the drive wheel 80 via the speed reducer 58, and the other route is a route transmitted to the first MG 20.

  First MG 20 and second MG 30 are, for example, three-phase AC rotating electric machines. First MG 20 and second MG 30 are driven by PCU 60.

  First MG 20 has a function as a generator that generates power using the power of engine 10 divided by power split device 40 and charges main battery 70 via PCU 60. Further, first MG 20 receives electric power from main battery 70 and rotates a crankshaft that is an output shaft of engine 10. Thus, the first MG 20 has a function as a starter for starting the engine 10.

  Second MG 30 has a function as a drive motor that applies driving force to drive wheels 80 using at least one of the electric power stored in main battery 70 and the electric power generated by first MG 20. Further, second MG 30 has a function as a generator for charging main battery 70 via PCU 60 using electric power generated by regenerative braking.

  The engine 10 is, for example, an internal combustion engine such as a gasoline engine or a diesel engine. The engine 10 includes a plurality of cylinders 102. Furthermore, the engine 10 is provided with an engine rotation speed sensor 11 for detecting the rotation speed Ne (hereinafter referred to as engine rotation speed) Ne of the crankshaft of the engine 10. The engine rotation speed sensor 11 transmits a signal indicating the detected engine rotation speed Ne to the ECU 200.

  Power split device 40 mechanically connects each of the three elements of drive shaft 16 for rotating drive wheel 80, the output shaft of engine 10, and the rotation shaft of first MG 20. The power split device 40 enables transmission of power between the other two elements by using any one of the three elements described above as a reaction force element. The rotation shaft of second MG 30 is connected to drive shaft 16.

  Power split device 40 is a planetary gear mechanism including a sun gear, a pinion gear, a carrier, and a ring gear. The pinion gear meshes with each of the sun gear and the ring gear. The carrier supports the pinion gear so as to be able to rotate and is coupled to the crankshaft of the engine 10. The sun gear is connected to the rotation shaft of the first MG 20. The ring gear is connected to the rotation shaft of second MG 30 and reduction gear 58 via drive shaft 16.

  Reducer 58 transmits the power from power split device 40 and second MG 30 to drive wheels 80. Reducer 58 transmits the reaction force from the road surface received by drive wheels 80 to power split device 40 and second MG 30.

  PCU 60 converts the DC power stored in main battery 70 into AC power for driving first MG 20 and second MG 30. PCU 60 includes a boost converter 62 and an inverter 64 controlled based on control signal S2 from ECU 200.

  Boost converter 62 boosts the voltage of the DC power received from main battery 70 and outputs the boosted voltage to inverter 64. Inverter 64 converts the DC power output from boost converter 62 into AC power and outputs the AC power to first MG 20 and / or second MG 30. Thereby, first MG 20 and / or second MG 30 are driven using the electric power stored in main battery 70. Inverter 64 converts AC power generated by first MG 20 and / or second MG 30 into DC power and outputs the DC power to boost converter 62. Boost converter 62 steps down the voltage of the DC power output from inverter 64 and outputs the voltage to main battery 70. Thereby, main battery 70 is charged using the electric power generated by first MG 20 and / or second MG 30. Boost converter 62 may be omitted.

  The main battery 70 is a power storage device and is a rechargeable DC power source. Main battery 70 is connected to PCU 60. As the main battery 70, for example, a secondary battery such as nickel metal hydride or lithium ion is used. The voltage of the main battery 70 is about 200V, for example. Main battery 70 is charged using the electric power generated by first MG 20 and / or second MG 30 as described above. The main battery 70 is not limited to a secondary battery, and may be a battery that can generate a DC voltage, such as a capacitor, a solar battery, or a fuel battery.

  The main battery 70 includes a battery temperature sensor 156 for detecting the battery temperature TMB of the main battery 70, a current sensor 158 for detecting the current IB of the main battery 70, and a voltage VB of the main battery 70. Voltage sensor 160 is provided.

  Battery temperature sensor 156 transmits a signal indicating battery temperature TMB to ECU 200. Current sensor 158 transmits a signal indicating current IB to ECU 200. Voltage sensor 160 transmits a signal indicating voltage VB to ECU 200.

  The accelerator position sensor 162 detects a depression amount AP of an accelerator pedal (not shown). The accelerator position sensor 162 transmits a signal indicating the accelerator pedal depression amount Ap to the ECU 200.

  The first resolver 12 detects the rotational speed Nm1 of the first MG 20. The first resolver 12 transmits a signal indicating the detected rotation speed Nm1 to the ECU 200. The second resolver 13 detects the rotational speed Nm2 of the second MG 30. The second resolver 13 transmits a signal indicating the detected rotation speed Nm2 to the ECU 200.

  The wheel speed sensor 14 detects the rotational speed Nw of the drive wheel 80. The wheel speed sensor 14 transmits a signal indicating the detected rotation speed Nw to the ECU 200. ECU 200 calculates vehicle speed V based on the received rotational speed Nw. ECU 200 may calculate vehicle speed V based on rotation speed Nm2 of second MG 30 instead of rotation speed Nw.

  ECU 200 generates a control signal S1 for controlling engine 10, and outputs the generated control signal S1 to engine 10. ECU 200 also generates a control signal S2 for controlling PCU 60 and outputs the generated control signal S2 to PCU 60.

  ECU 200 controls the entire hybrid system, that is, the charging / discharging state of main battery 70 and the operating states of engine 10, first MG 20 and second MG 30 so that vehicle 1 can operate most efficiently by controlling engine 10, PCU 60, and the like. To do.

  ECU 200 calculates a required driving force corresponding to the accelerator pedal depression amount AP. ECU 200 controls the torque of first MG 20 and second MG 30 and the output of engine 10 in accordance with the calculated required driving force.

  In the vehicle 1 having the above-described configuration, when the engine 10 is inefficient at the time of starting or running at a low speed, the vehicle 1 runs only with the second MG 30 with the engine 10 stopped. Further, during normal travel, for example, the power split device 40 divides the power of the engine 10 into two paths of power. The drive wheel 80 is directly driven by one power. The first MG 20 is driven with the other power to generate power. At this time, ECU 200 drives second MG 30 using the generated electric power. In this way, driving of the driving wheel 80 is performed by driving the second MG 30.

  When the vehicle 1 decelerates, the second MG 30 driven by the rotation of the drive wheels 80 functions as a generator to perform regenerative braking. Electric power recovered by regenerative braking is stored in the main battery 70. ECU 200 increases the output of engine 10 to increase the first MG 20 when the remaining capacity of the power storage device (described in the following description as SOC (State of Charge)) decreases and charging is particularly necessary. Increase the amount of power generated by Thereby, the SOC of the main battery 70 is increased. In addition, the ECU 200 may perform control to increase the driving force from the engine 10 as necessary even during low-speed traveling. For example, when the main battery 70 needs to be charged as described above, when an auxiliary machine such as an air conditioner is driven, or when the temperature of the cooling water of the engine 10 is increased to a predetermined temperature.

  When the vehicle 1 is traveling on a rough road as described above, the rotational state of the drive wheel 80 repeats the slip state and the grip state, resulting in rotational fluctuations and resonance in the drive system 84. There is. When such resonance occurs, it is desirable to reduce the driving force of the vehicle in order to protect the components of the drive system 84 from excessive input due to resonance. However, if it is erroneously determined when the resonance is detected and it is determined whether the traveling road surface of the vehicle is a rough road, the driving force of the vehicle 1 may be reduced when the vehicle 1 is not traveling on the rough road. is there.

  Therefore, in the present embodiment, ECU 200 shows a case where the integrated value of the magnitude of the fluctuation component of rotation speed Nm2 of second MG 30 is larger than the first threshold, and the integrated value tends to increase. When the value is larger than the second threshold value, the driving force is limited. Both the first threshold value and the second threshold value are values for determining that the vehicle 1 is traveling on a rough road. The rough road refers to a road surface in which driving wheels such as a wavy road surface having unevenness on the ground surface or a road surface partially having a low friction coefficient part alternately repeats a slip state and a grip state.

  FIG. 2 shows a functional block diagram of ECU 200 mounted on vehicle 1 according to the present embodiment. The ECU 200 includes an integration processing unit 350, an elapsed time determination unit 358, a number calculation unit 360, a resonance determination unit 362, a driving force limiting unit 364, a release determination unit 366, a rate determination unit 368, and a return control unit. 370.

  Integration processing unit 350 includes a band pass filter 352, an integration unit 354, and a low pass filter 356.

  The band pass filter 352 extracts a fluctuation component of a predetermined frequency band corresponding to the resonance frequency band from the rotation speed Nm2 acquired from the second resolver 13 as the first filter output value Fo1. The operation of the bandpass filter 352 is a well-known technique and will not be described in detail. Moreover, since the predetermined frequency band corresponding to the resonance frequency band varies depending on the type of the vehicle 1 and the like, it may be adapted experimentally or designally.

  The integrating unit 354 integrates (by time integration) the absolute value of the first filter output value Fo1 extracted by the bandpass filter 352 in a predetermined period Ta before the current time point, and calculates an integrated value In. The predetermined period Ta is desirably a time corresponding to one cycle of the fluctuation component, for example. The predetermined period Ta is not limited to a constant value, and may be changed according to the rotational speed Nm2 of the second MG 30, for example. The low pass filter 356 calculates a second filter output value Fo2 obtained by removing noise components of a predetermined frequency or higher from the integrated value In calculated by the integrating unit 354. The operation of the low-pass filter is a well-known technique and will not be described in detail. Note that the low-pass filter 356 may be omitted.

  For example, a case is assumed where the rotation speed Nm2 of the second MG 30 showing the change as shown in the uppermost timing chart of FIG. 3 is input from the second resolver 13 to the integration processing unit 350.

  As shown in the second timing chart from the top in FIG. 3, the bandpass filter 352 outputs a fluctuation component of the resonance frequency band as the first filter output value Fo1 based on the input rotational speed Nm2.

  As shown in the third timing chart from the top in FIG. 3, the integrating unit 354 calculates the integrated value In by integrating the absolute value of the first filter output value Fo1 in the predetermined period Ta before the current time.

  The low-pass filter 356 removes a noise component of a predetermined frequency or more from the integrated value In calculated by the integrating unit 354 and outputs a second filter output value Fo2 as shown in the lowest timing chart of FIG.

  The elapsed time determination unit 358 determines whether or not a predetermined time Tb has elapsed since the timer count value Ct was reset to the initial value Ct (0) (Ct (0) = 0 in the present embodiment). . That is, the elapsed time determination unit 358 determines whether or not the timer count value Ct is equal to or greater than the value Ct (1) corresponding to the predetermined time Tb. In the following description, “resetting the timer count value Ct to the initial value Ct (0)” will be referred to as “clearing the timer”. In the present embodiment, the predetermined time Tb may be a constant value, for example, or may be one cycle of a fluctuation component calculated from the rotational speed Nm2.

  A predetermined value A (A = 1 in the present embodiment) is added to the timer count value Ct every calculation cycle. For example, the elapsed time determination unit 358 may turn on the elapsed determination flag when it is determined that the predetermined time Tb has elapsed since the timer was cleared. The elapsed time determination unit 358 clears the timer when it is determined that the timer count value Ct is equal to or greater than Ct (1).

  The number calculation unit 360 calculates the number of times that the amount of change in the predetermined time Tb of the second filter output value Fo2 is greater than the threshold value α as a value indicating an increasing tendency.

  Specifically, every time the elapsed time determination unit 358 determines that the predetermined time Tb has elapsed from the timer clear, the number calculation unit 360 determines the second filter output value (hereinafter, the current second filter output). The output difference Fo2−Fo2 ′ between Fo2 (described as a value) and the second filter output value before the predetermined time Tb (hereinafter referred to as the previous second filter output value) Fo2 ′ is equal to or greater than the threshold value α. It is determined whether or not. The threshold value α is a positive value and is a value for determining whether or not the second filter output value Fo2 tends to increase.

  When the output difference Fo2−Fo2 ′ is greater than or equal to the threshold value α, the number calculation unit 360 adds a predetermined value B (B = 1 in the present embodiment) to the increment count value Ci, and adds The calculated value is calculated as the number of times of increasing tendency.

  When the output difference Fo2−Fo2 ′ is smaller than the threshold value α, the number calculation unit 360 sets the increment count value Ci to the initial value Ci (0) (Ci (0) = 0 in the present embodiment). Reset to.

  For example, it is assumed that the second filter output value shown in the upper timing chart of FIG. As shown in the middle timing chart of FIG. 4, the timer is cleared every time a predetermined time Tb elapses.

  For example, when the elapsed time determination unit 358 determines that the predetermined time Tb has elapsed at time T (1), the number calculation unit 360 includes the second filter output value Fo2 (1) at time T (1), An output difference Fo2 (1) −Fo2 (0) from the second filter output value Fo2 (0) at time T (0) before the predetermined time Tb of time T (1) is calculated. When the output difference Fo2 (1) −Fo2 (0) is greater than or equal to the threshold value α, the number calculation unit 360 adds a predetermined value B (= 1) to the current increase count value Ci.

  When the elapsed time determination unit 358 determines again that the predetermined time Tb has elapsed at time T (2), the number calculation unit 360 determines the second filter output value Fo2 (2) at time T (2) and the time An output difference Fo2 (2) −Fo2 (1) from the second filter output value Fo2 (1) at a time T (1) before a predetermined time Tb of T (2) is calculated. The count calculation unit 360 resets the increase count value Ci to the initial value Ci (0) (= 0) when the output difference Fo2 (2) −Fo2 (1) is smaller than the threshold value.

  The resonance determination unit 362 determines whether or not the second filter output value Fo2 is equal to or greater than the threshold value β and the increase count value Ci is equal to or greater than the threshold value γ. The resonance determination unit 362 turns on the resonance determination flag when the second filter output value Fo2 is equal to or greater than the threshold value β and the increase count value Ci is equal to or greater than the threshold value γ. It may be. Further, the resonance determination unit 362 calculates the second filter output value Fo2 and the second filter output value Fo2 ′ of the previous time and the second filter output value Fo2 ′ of the previous time. It is also possible to determine whether or not the second filter output value Fo2 is equal to or greater than the threshold value β and the increase count value Ci is equal to or greater than the threshold value γ. Good. . The threshold values β and γ are values for determining that the resonance caused by the rough road traveling of the vehicle 1 is occurring in the drive system 84.

  The driving force limiting unit 364 drives when the resonance determination unit 362 determines that the second filter output value Fo2 is equal to or greater than the threshold value β and the increase count value Ci is equal to or greater than the threshold value γ. Perform force limit control.

  The driving force limiting unit 364 performs driving force limiting control with respect to the required driving force required for the vehicle 1 with the upper limit value Fd (1) being lower than the upper limit value Fd (0) in the normal state. . The upper limit value in the normal state is an upper limit value of the required driving force when the second filter output value Fo2 is lower than the threshold value β or when the increase count value Ci is lower than the threshold value γ.

  When the required driving force is equal to or less than the upper limit value Fd (1), the driving force limiting unit 364 uses the required driving force as the final required driving force, and the vehicle 1 (that is, the first MG 20, the second MG 30, and the engine 10). To control. When the required driving force is larger than the upper limit value Fd (1), the driving force limiting unit 364 controls the vehicle 1 using Fd (1) as the final required driving force.

  For example, the driving force limiting unit 364 may execute the driving force limiting control when the resonance determination flag is on. The driving force limiter 364 controls the driving force when the second filter output value Fo2 is greater than or equal to the threshold value β and the increase count value Ci is determined to be greater than or equal to the threshold value γ. Or the second filter output value Fo2 is greater than or equal to the threshold value β, and the requested drive is performed when it is determined that the increase count value Ci is greater than or equal to the threshold value γ. You may make it change the upper limit of force so that it may approach Fd (1) with progress of time. As an aspect of the change of the upper limit value, it may be changed linearly with the passage of time or may be changed nonlinearly.

  The cancellation determination unit 366 determines whether or not the second filter output value Fo2 is equal to or less than the threshold value δ when the driving force limit control is executed. The threshold value δ is not particularly limited as long as it is a value equal to or smaller than the threshold value β. For example, when the resonance determination flag is in the on state, the cancellation determination unit 366 determines whether the second filter output value Fo2 is equal to or less than the threshold value δ, and the second filter output value Fo2 is set. The release determination flag may be turned on when the threshold value δ or less.

  When the cancellation determination unit 366 determines that the second filter output value Fo2 is equal to or less than the threshold δ, the rate determination unit 368 uses the second filter output value Fo2 and a map or the like to return the driving force. Determine the return rate at. The return rate is a value that defines a change characteristic when the upper limit value of the required drive force is changed from Fd (1) to Fd (0) upon return from the drive force limit control.

  In the present embodiment, for example, rate determination unit 368 may determine the return rate so that the amount of change in the upper limit value of the requested driving force increases with the passage of time, or the request with the passage of time. The return rate may be determined so that the amount of change in the upper limit value of the driving force decreases, or a fixed value may be determined as the return rate regardless of the passage of time. The rate determining unit 368 determines the return rate from a map, a mathematical formula, a table, or the like in which the relationship between the second filter output value Fo2 and the return rate (a constant value or a change amount) is defined.

  When the release determination unit 366 determines that the second filter output value Fo2 is equal to or less than the threshold value δ, the return control unit 370 performs drive force return control based on the return rate determined by the rate determination unit 368. Execute.

  The return control unit 370 returns the upper limit value of the requested driving force from Fd (1) to Fd (0) when the release determination unit 366 determines that the second filter output value Fo2 is equal to or less than the threshold value δ. Change over time according to the rate. The return control unit 370 maintains the upper limit value Fd (0) when the upper limit value of the requested driving force returns to Fd (0).

  The return control unit 370 may start the return control of the driving force when the release determination unit 366 determines that the second filter output value Fo2 is equal to or less than the threshold value δ, or The driving force return control may be started after a predetermined time has elapsed since the second filter output value Fo2 is determined to be equal to or less than the threshold value δ.

  In the present embodiment, an integration processing unit 350, an elapsed time determination unit 358, a number calculation unit 360, a resonance determination unit 362, a driving force limiting unit 364, a release determination unit 366, a rate determination unit 368, The return control unit 370 is described as functioning as software that is realized when the CPU of the ECU 200 executes a program stored in the memory, but may be realized as hardware. Such a program is recorded on a storage medium and mounted on the vehicle.

  With reference to FIG. 5, a control structure of a program that limits the driving force in accordance with second filter output value Fo2 executed by ECU 200 mounted on the vehicle according to the present embodiment will be described.

  In step (hereinafter, step is referred to as S) 100, ECU 200 obtains rotation speed Nm 2 of second MG 30 from second resolver 13. In S102, ECU 200 executes a bandpass filter process on the acquired rotation speed Nm2. In other words, the ECU 200 calculates the first filter output value Fo1 corresponding to the fluctuation component of the resonance frequency band based on the rotational speed Nm2.

  In S104, ECU 200 executes an integrated value calculation process. That is, the ECU 200 calculates the integrated value In by integrating the absolute value of the first filter output value Fo1 in the predetermined period Ta before the current time point. In S106, ECU 200 performs a low-pass filter process on integrated value In. That is, the ECU 200 calculates the second filter output value Fo2 from which noise components having a predetermined frequency or higher are removed based on the integrated value In.

  In S108, ECU 200 adds “1” to timer count value Ct. In S110, ECU 200 determines whether or not timer count value Ct is equal to or greater than value Ct (1) corresponding to predetermined time Tb. If timer count value Ct is equal to or greater than value Ct (1) corresponding to predetermined time Tb (YES in S110), the process proceeds to S112. If not (NO in S110), the process returns to S100. In S112, ECU 200 resets timer count value Ct to initial value “0” and clears the timer.

  In S114, ECU 200 determines whether or not output difference Fo2-Fo2 'between current second filter output value Fo2 and previous second filter output value Fo2' before a predetermined time Tb is greater than or equal to threshold value α. judge. If output difference Fo2−Fo2 ′ is greater than or equal to threshold value α (YES in S114), the process proceeds to S116. If not (NO in S114), the process proceeds to S118.

  In S116, ECU 200 adds “1” to increase count value Ci. In S118, ECU 200 resets increase count value Ci to initial value “0”. In S120, ECU 200 stores the current second filter output value Fo2 in the memory. The stored second filter output value Fo2 is used as the “previous second filter output value Fo2 ′” at the next calculation of the output difference (that is, after the predetermined time Tb has elapsed).

  In S122, ECU 200 determines whether or not second filter output value Fo2 is equal to or greater than threshold value β and increase count value Ci is equal to or greater than threshold value γ. If second filter output value Fo2 is equal to or greater than threshold value β and increase count value Ci is equal to or greater than threshold value γ (YES in S122), the process proceeds to S124. If not (NO in S122), the process returns to S100. In S122, ECU 200 executes drive force limiting control.

  Next, with reference to FIG. 6, a control structure of a program that limits the driving force according to the second filter output value Fo2 executed by the ECU 200 mounted on the vehicle according to the present embodiment will be described.

  In S200, ECU 200 determines whether or not the driving force is being limited, that is, whether or not the driving force limiting control is being executed. If the driving force is limited (YES in S200), the process proceeds to S202. If not (NO in S200), the process returns to S200.

  In S202, ECU 200 determines whether or not second filter output value Fo2 is equal to or smaller than threshold value δ. If second filter output value Fo2 is equal to or smaller than threshold value δ (YES in S202), the process proceeds to S204. If not (NO in S202), the process proceeds to S200.

  In S204, ECU 200 determines the return rate using second filter output value Fo2 and the map. The method for determining the return rate is as described above, and detailed description thereof will not be repeated. In S206, ECU 200 executes drive force return control in accordance with the determined return rate.

  The operation of ECU 200 mounted on vehicle 1 according to the present embodiment based on the above-described structure and flowchart will be described with reference to FIGS.

  For example, it is assumed that the vehicle 1 is traveling. At this time, the rotation speed Nm2 of the second MG 30 is acquired (S100), and the first filter corresponding to the fluctuation component of the resonance frequency band is obtained by performing bandpass filter processing on the acquired rotation speed Nm2 of the second MG 30. An output value Fo1 is calculated (S100). Further, an integrated value In for a predetermined period Ta is calculated based on the calculated first filter output value Fo1 (S104). A low-pass filter process is performed on the calculated integrated value In to calculate a second filter output value Fo2 from which noise components of a predetermined frequency or higher are removed (S106).

  The timer count value Ct is incremented by “1” every calculation cycle (S108), and whenever the predetermined time Tb elapses (YES in S110), the timer is cleared (S112), The output difference Fo2−Fo2 ′ between the filter output value Fo2 and the previous second filter output value Fo2 ′ before the predetermined time Tb is compared with the threshold value α (S114). If output difference Fo2−Fo2 ′ is greater than or equal to threshold value α (YES in S114), “1” is added to increase count value Ci (S116).

<When resonance occurs due to driving on a rough road>
When the vehicle 1 is traveling on a rough road, it is assumed that the drive wheel 80 repeats a slip state and a grip state and resonance occurs in the drive system 84. At this time, rotational fluctuation occurs in the resonance frequency band of the rotational speed Nm2 of the second MG 30. Therefore, as shown in FIG. 7, the second filter output value Fo2 increases with the passage of time. When output difference Fo2−Fo2 ′ is equal to or larger than threshold value α (YES in S114), “1” is added to increase count value Ci (S116).

  When resonance occurs, rotation fluctuations in the resonance frequency band continuously occur, and thus the state where the output difference Fo2−Fo2 ′ is equal to or greater than the threshold value α continues. As a result, the increase count value Ci increases with the passage of time.

  When increase count value Ci is equal to or greater than threshold value γ at time T (3), second filter output value Fo2 is smaller than threshold value β (NO in S122), so that drive force limiting control is performed. Not executed. On the other hand, when increase count value Ci is equal to or greater than threshold value γ at time T (4) and second filter output value Fo2 is equal to or greater than threshold value β (in S122). YES), driving force limiting control is executed (S124).

  When the driving force limit control is executed, the upper limit value of the required driving force decreases from Fd (0) to Fd (1), and thus the driving force of the vehicle 1 tends to decrease. Therefore, since the state where the driving wheel 80 repeats the slip state and the grip state is suppressed, the occurrence of resonance is suppressed. As a result, excessive input due to resonance is suppressed in the drive system 84, so that the components can be protected.

<When a single vibration occurs in the vehicle>
When a single vibration is generated in the vehicle 1, as shown in FIG. 8, the rotational fluctuation occurs in the resonance frequency band. However, when a single vibration occurs, the rotational fluctuation in the resonance frequency band is only temporarily generated as compared with the case where the resonance occurs. Therefore, increase count value Ci is cleared when output difference Fo2−Fo2 ′ becomes smaller than threshold value α (NO in S114) before it reaches or exceeds threshold value γ. (S118). As a result, even when second filter output value Fo2 becomes equal to or larger than threshold value β at time T (5), increase count value Ci is smaller than threshold value γ (NO in S122). The driving force limit control is not executed.

<When returning from drive force limit control>
As shown in FIG. 9, for example, at time T (6), second filter output value Fo2 becomes equal to or greater than threshold value β and increase count value Ci is also equal to or greater than threshold value γ (YES in S122). Assume that the driving force limiting control is executed (S124).

  At this time, since the upper limit value of the required driving force is limited to the normal upper limit value Fd (0) to Fd (1), the required driving force with respect to the vehicle 1 starts to decrease from the time T (6). At time T (7), the upper limit value of the required driving force is Fd (1). After time T (7), Fd (1) is maintained as the upper limit value of the required driving force.

  When the upper limit value of the required driving force is reduced as compared with the normal time, the driving force of the vehicle 1 is reduced. As a result, the magnitude of the rotational fluctuation component in the resonance frequency band of the second MG 30 decreases. For this reason, the second filter output value Fo2 decreases.

  If the second filter output value Fo2 is equal to or less than the threshold value δ (YES in S202) during execution of the driving force limiting control at time T (8) (YES in S200), the return rate is determined. (S204). Then, at the time T (9) after a predetermined time has elapsed from the time when it is determined that the second filter output value Fo2 is equal to or less than the threshold value δ, the driving force return control is executed (S206).

  Drive force return control is executed in accordance with the determined return rate. Therefore, the upper limit value of the required driving force changes so that the amount of change in the upper limit value increases as time elapses from Fd (1) to Fd (0). When the upper limit value of the required driving force returns to Fd (0) at time T (10), Fd (0) is maintained as the upper limit value of the required driving force after time T (10). Is done.

  As described above, according to the vehicle according to the present embodiment, even when a single vibration occurs at the rotational speed Nm2 of the second MG 30 and the magnitude of the rotational fluctuation component in the resonance frequency band temporarily increases, It is possible to suppress erroneous determination that the resonance caused by the rough road traveling of the vehicle has occurred. Further, when it is determined that the vehicle is traveling on a rough road, parts of the drive system 84 are protected by executing the drive force restriction control. Further, by determining the return rate according to the second filter output value Fo2, the upper limit value of the driving force is quickly returned when the vehicle has escaped from a rough road, and the drive is continued when the rough road is continuing. The upper limit value of the force can be gradually restored. Thus, the driving force can be returned according to the traveling road surface of the vehicle. Therefore, it is possible to provide a vehicle and a vehicle control method that can suppress erroneous determination of the traveling road surface and realize driving force control according to the traveling road surface.

  In the present embodiment, the ECU 200 has been described as calculating the second filter output value Fo2 using the rotation speed Nm2 of the second MG 30, but among the components that rotate in conjunction with the rotation of the drive wheels 80 and the drive wheels 80, The second filter output value Fo2 may be calculated using at least one of the rotational speeds, and is not particularly limited to using the rotational speed Nm2 of the second MG 30.

  In the present embodiment, the ECU 200 has been described assuming that Fd (1) smaller than the normal upper limit value Fd (0) is the upper limit value of the requested driving force when the driving force limit control is executed. For example, the vehicle 1 may be controlled by using a value obtained by multiplying the required driving force by a coefficient smaller than 1 as the final required driving force when the driving force limiting control is executed.

  In the present embodiment, the vehicle 1 has been described as being a hybrid vehicle. However, the vehicle 1 is not particularly limited to a hybrid vehicle. The vehicle 1 may be an electric vehicle, for example, or may be a vehicle using only an internal combustion engine as a power source.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 vehicle, 10 engine, 11 engine rotation speed sensor, 12, 13 resolver, 14 wheel speed sensor, 16 drive shaft, 20, 30 MG, 40 power split device, 58 speed reducer, 60 PCU, 62 boost converter, 64 inverter, 70 main battery, 80 drive wheel, 82 drive shaft, 84 drive system, 86 transmission, 102 cylinder, 156 battery temperature sensor, 158 current sensor, 160 voltage sensor, 162 accelerator position sensor, 200 ECU, 350 integration processing unit, 352 band Pass filter, 354 integrating unit, 356 low-pass filter, 358 elapsed time determining unit, 360 times calculating unit, 362 resonance determining unit, 364 driving force limiting unit, 366 release determining unit, 368 rate determining unit, 370 return control unit

Claims (6)

A drive system including a drive wheel for generating a drive force in a vehicle, an internal combustion engine, and a drive transmission device for mechanically connecting the internal combustion engine and the drive wheel;
A detection unit for detecting a rotation speed of at least one of the drive wheel and a component that rotates in conjunction with the rotation of the drive wheel;
A control unit for controlling the driving force based on the rotation speed detected by the detection unit,
The control unit is a case where the magnitude of the fluctuation component of the rotational speed is greater than a first threshold value, and a value indicating an increasing tendency of the magnitude of the fluctuation component is greater than the second threshold value. If large, the vehicle limits the driving force.   If the magnitude of the fluctuation component is smaller than a third threshold value less than or equal to the first threshold value after the driving force is limited, the control unit is based on the magnitude of the fluctuation component. The vehicle according to claim 1, wherein a return rate of the driving force is determined, and the restriction of the driving force is released according to the determined return rate. Each of the first threshold value and the second threshold value is a value for determining that a resonance caused by a rough road traveling of the vehicle is occurring in the drive system,
The control unit extracts the fluctuation component in a resonance frequency band of the rotational speed in a predetermined period before a current time point, and calculates the magnitude of the fluctuation component based on the extracted fluctuation component. The vehicle according to 1 or 2.   The vehicle according to claim 1, wherein the control unit calculates the number of times the amount of change in the magnitude of the fluctuation component in a predetermined period is greater than a fourth threshold value as a value indicating the increasing tendency.   The drive transmission device includes a drive shaft for rotating the drive wheel, a first rotating electrical machine, a second rotating electrical machine provided on the drive shaft, the drive shaft, an output shaft of the internal combustion engine, and the first Power that can transmit power between the other two elements by mechanically connecting each of the three elements of the rotating shaft of the rotating electrical machine and using any one of the three elements as a reaction force element. The vehicle according to claim 1, comprising a transmission device. A vehicle control method for use in a vehicle equipped with a drive system including a drive wheel for generating a drive force, an internal combustion engine, and a drive transmission device for mechanically connecting the internal combustion engine and the drive wheel. There,
Detecting a rotational speed of at least one of the drive wheel and a component that rotates in conjunction with rotation of the drive wheel;
When the magnitude of the fluctuation component of the rotational speed is larger than the first threshold and the value indicating the increasing tendency of the magnitude of the fluctuation component is larger than the second threshold, Limiting the driving force of the vehicle.

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