JP2015131609A - vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle in which giving a driver feeling of strangeness is suppressed when a vehicle speed reaches an ASL (Adjustable Speed Limiter) vehicle speed.SOLUTION: A vehicle 1 includes a continuously variable transmission (materialized by a first motor 20 and a power division device 40) provided between an engine 10 and a driving wheel 80. A control device 200 performs: fuel economy-prioritized engine control to prioritize in fuel economy and engine speed increase control (acceleration feeling performance control) to increase a speed of the engine 10 in accordance with at least any of a vehicle speed rise, an increase in accelerator opening degree and a temporal elapse; and vehicle speed limit control (ASL control) to limit a vehicle speed at an upper limit vehicle speed. When the vehicle speed reaches the upper limit vehicle speed (an ASL vehicle speed) during performing of the engine speed increase control, the control device 200 releases the engine speed increase control and transitions to the fuel economy-prioritized engine control.

Description

  The present invention relates to a vehicle, and more particularly, to a hybrid vehicle including a continuously variable transmission.

  Japanese Patent Laying-Open No. 2010-006334 (Patent Document 1) discloses an ASL (Adjustable Speed Limiter) control device that controls the vehicle so that the vehicle speed does not increase further when the accelerator is depressed when the set speed limit is reached. ing.

JP 2010-006334 A JP 2003-254421 A JP 2012-153344 A

  In a vehicle equipped with a continuously variable transmission, when there is an acceleration request by the driver's accelerator operation, the introduction of a rotation speed increase control that produces an acceleration feeling by controlling the engine rotation speed in conjunction with the accelerator operation is introduced. It is being considered.

  When such a technique is used in a vehicle in combination with an ASL control device, the vehicle speed does not increase even if the driver depresses the accelerator when the vehicle speed reaches the speed limit. However, the engine speed increases due to the rotational speed increase control.

  Therefore, although the vehicle speed does not increase, only the engine speed increases, which may give the driver a feeling of strangeness.

  In addition, since the vehicle speed is limited during ASL control, there is a possibility that the vehicle speed in the discharge region of the rotation speed increase control continues and the power storage device is excessively discharged.

  The object of the present invention is to avoid excessive discharge of the power storage device in a vehicle that can execute the rotational speed increase control in combination with ASL control, and to suppress the driver from feeling uncomfortable when the vehicle speed reaches the ASL vehicle speed. Is to provide a vehicle.

  (1) In summary, the present invention is a vehicle, and includes an engine, a continuously variable transmission provided between the engine and driving wheels, and a control device that controls the engine and the continuously variable transmission. The control device performs either fuel efficiency priority engine control for giving priority to fuel efficiency, or rotational speed increase control for increasing the rotational speed of the engine in accordance with at least one of a vehicle speed increase, an accelerator opening increase, and a lapse of time. Then, vehicle speed limiting control is performed to limit the vehicle speed to the upper limit vehicle speed. When the vehicle speed reaches the upper limit vehicle speed during execution of the rotation speed increase control, the control device cancels the rotation speed increase control and shifts to fuel efficiency priority engine control.

  When the vehicle speed reaches the upper limit vehicle speed, the vehicle speed does not increase any further. In this case, if the engine speed increases, the driver may feel uncomfortable. In addition, when the driver recognizes that the vehicle speed is limited, in response to changing the accelerator opening, even if the accelerator opening is changed, the vehicle speed is limited to a constant value. If only the engine speed changes, the driver may still feel uncomfortable. When the vehicle speed reaches the upper limit vehicle speed, the rotational speed increase control is canceled, so that such a sense of incongruity can be reduced.

  (2) Preferably, the vehicle is a hybrid vehicle that outputs the driving force of the vehicle by the power of the engine and the power of the motor driven by the electric power from the battery. When the fuel efficiency priority engine control is applied to the command engine rotation speed, the difference between the vehicle speed and the upper limit vehicle speed is smaller before the vehicle speed reaches the upper limit vehicle speed during the execution of the rotation speed increase control. Increase to approach the determined engine speed.

  When canceling the speed increase control, if the target engine speed after the shift to fuel efficiency priority engine control deviates from the current engine speed, the engine speed will change suddenly, and the driver will feel uncomfortable. I will give it. According to the above control, the control is performed so that the engine speed approaches the command value of the engine speed after the rotational speed increase control is canceled as the vehicle speed approaches the upper limit vehicle speed, so that a sudden change in the engine speed can be suppressed.

  (3) Preferably, the vehicle is a hybrid vehicle that outputs the driving force of the vehicle by the power of the engine and the power of the motor driven by the electric power from the battery. When starting the execution of the rotation speed increase control, the control device sets the initial command value of the engine rotation speed to a larger value as the difference between the vehicle speed and the upper limit vehicle speed is smaller before the vehicle speed reaches the upper limit vehicle speed. .

  When canceling the rotation speed increase control, if the engine rotation speed after shifting to fuel efficiency priority engine control deviates from the current engine rotation speed, the engine rotation speed will change suddenly, giving the driver a sense of incongruity. End up. According to the above control, the initial rotational speed command value is determined based on the difference between the vehicle speed and the upper limit vehicle speed, and the control is performed in advance so as to approach the engine rotational speed command value after the rotational speed increase control is released. Sudden changes in engine speed can be suppressed.

  (4) Preferably, the vehicle is a hybrid vehicle that outputs the driving force of the vehicle by the power of the engine and the power of the motor driven by the electric power from the battery. The control device increases the change rate of the command engine rotation speed as the difference between the vehicle speed and the upper limit vehicle speed is smaller before the vehicle speed reaches the upper limit vehicle speed during execution of the rotation speed increase control.

  When canceling the rotation speed increase control, if the engine rotation speed after shifting to fuel efficiency priority engine control deviates from the current engine rotation speed, the engine rotation speed will change suddenly, giving the driver a sense of incongruity. End up. According to the above control, the rate of increase in the rotational speed is increased as the vehicle speed approaches the upper limit vehicle speed, and the control is performed so as to approach the command value of the engine rotational speed after the rotational speed increase control is canceled. Sudden changes can be suppressed.

  (5) Preferably, the vehicle is a hybrid vehicle that outputs the driving force of the vehicle by the power of the engine and the power of the motor driven by the electric power from the battery. The control device sets the lower limit value of the command engine rotation speed to a larger value as the difference between the vehicle speed and the upper limit vehicle speed becomes smaller before the vehicle speed reaches the upper limit vehicle speed during the rotation speed increase control. Limit engine speed.

  When canceling the rotation speed increase control, if the engine rotation speed after shifting to fuel efficiency priority engine control deviates from the current engine rotation speed, the engine rotation speed will change suddenly, giving the driver a sense of incongruity. End up. According to the above control, since the lower limit value of the engine rotation speed is increased as the vehicle speed approaches the upper limit vehicle speed, the control is performed so as to approach the command value of the engine rotation speed after the release of the rotation speed increase control. Sudden changes in engine speed can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, when the ASL vehicle speed is reached | attained in the vehicle which can be performed combining rotational speed increase control with ASL control, it is suppressed that a driver feels strange.

1 is a diagram showing an overall configuration of a vehicle 1 according to the present embodiment. It is a wave form chart for explaining optimal fuel consumption control and acceleration feeling production control. It is a figure for demonstrating the problem in the case of applying acceleration feeling production | presentation control to ASL control. It is a flowchart which shows the flow of the process performed when ECU200 controls vehicle driving force. It is a figure which shows typically the calculation method of the optimal fuel consumption rotational speed NEef and the optimal fuel consumption torque TEef by optimal fuel consumption control. It is a figure which shows typically the setting method of instruction | command engine speed NEcom and instruction | command engine torque TEcom by acceleration feeling effect control. FIG. 6 is an operation waveform diagram for explaining an operation when the control of the first embodiment is realized. In Embodiment 2, it is a flowchart which shows the flow of the process performed when ECU200 controls vehicle driving force. It is a flowchart which shows the detailed flow of the calculation process (process of S61S of FIG. 8) of the initial value NEini of an engine speed. It is a figure which shows the relationship between the initial value NEini determined by S61E of FIG. 9, and (DELTA) Vasl. It is a figure which shows typically the content of the initial value correction process. It is a figure for demonstrating the change of the engine speed when an initial value correction process is applied. It is a flowchart which shows the detailed flow of a calculation process (process of S63 of FIG. 3) of increase rate (DELTA) NE of an engine speed. It is a figure which shows the relationship between increase rate (DELTA) NE and (DELTA) Vasl determined by S63F of FIG. It is a figure for demonstrating the change of an engine speed when an increase rate correction process is applied. It is a flowchart which shows the detailed flow of the calculation process (a part of process of S65S of FIG. 8) of the lower limit NEmin of engine speed. It is a figure which shows the relationship between lower limit NEmin and (DELTA) Vasl determined by S65E of FIG. It is a figure for demonstrating the change of an engine speed when a lower limit correction process is applied.

  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.

  In this specification, the term “electric power” may mean electric power (work rate) in a narrow sense, and may mean electric energy (work amount) or electric energy, which is electric power in a broad sense, and the term is used. It is interpreted elastically according to the situation to be done.

[Embodiment 1]
<Overall configuration of vehicle>
FIG. 1 is a diagram showing an overall configuration of a vehicle 1 according to the present embodiment. The vehicle 1 includes an engine 10, a drive shaft 16, a first motor generator (hereinafter referred to as “first motor”) 20, a second motor generator (hereinafter referred to as “second motor”) 30, and a power split device 40. , A speed reducer 58, a PCU (Power Control Unit) 60, a battery 70, a drive wheel 80, a vehicle speed sensor 3, an accelerator opening sensor 203, and an ECU (Electronic Control Unit) 200.

  The vehicle 1 is a hybrid vehicle that can run with the power of at least one of the engine 10 and the second motor 30.

  The power generated by the engine 10 is divided into a path transmitted to the drive shaft 16 (drive wheels 80) and a path transmitted to the first motor 20 by the power split device 40.

  The first motor 20 and the second motor 30 are three-phase AC rotating electric machines driven by the PCU 60. The first motor 20 can generate power using the power of the engine 10 divided by the power split device 40. The second motor 30 can generate power using at least one of the electric power stored in the battery 70 and the electric power generated by the first motor 20. The power generated by the second motor 30 is transmitted to the drive wheels 80 via the drive shaft 16. The second motor 30 also functions as a regenerative brake by generating electric power using the rotational energy of the drive shaft 16. The electric power generated by the second motor 30 is charged to the battery 70 via the PCU 60.

  Power split device 40 is a planetary gear mechanism including a sun gear, a ring gear, a pinion gear, and a carrier. The sun gear is connected to the first motor 20. The ring gear is connected to the second motor 30 and the drive wheel 80 via the drive shaft 16. 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 engine 10, the first motor 20, and the second motor 30 are connected via a power split device 40 including a planetary gear, so that the engine rotation speed NE, the first motor rotation speed NM1, and the second motor rotation speed NM2 are: In the collinear diagram of the power split device 40, a relationship is formed by a straight line (a relationship in which if any two values are determined, the remaining one value is also uniquely determined).

  For example, if the first motor rotation speed NM1 and the second motor rotation speed NM2 are determined, the remaining engine rotation speed NE is uniquely determined. In other words, even if the second motor rotation speed NM2 is constant, the engine rotation speed NE can be freely changed by adjusting the first motor rotation speed NM1. Here, since the second motor 30 is connected to the drive wheels 80, the second motor rotation speed NM2 is a value corresponding to the vehicle speed V. Therefore, the ratio of the engine rotational speed NE to the vehicle speed V can be switched steplessly by adjusting the first motor rotational speed NM1. That is, in the vehicle 1, the first motor 20 and the power split device 40 function as an electric continuously variable transmission that can switch the ratio of the engine rotational speed NE to the vehicle speed V steplessly. The vehicle to which the present invention can be applied is not limited to a vehicle having an electric continuously variable transmission, and can also be applied to a vehicle having a mechanical (for example, belt type) continuously variable transmission.

  The PCU 60 is a power conversion device that performs power conversion among the battery 70, the first motor 20, and the second motor 30 based on a control signal from the ECU 200.

  The battery 70 is a secondary battery including, for example, a nickel metal hydride battery or a lithium ion battery. The voltage of the battery 70 is about 200V, for example. The battery 70 is charged using the electric power generated by the first motor 20 and / or the second motor 30 as described above. The battery 70 may be a power storage device that can input and output power between the first motor 20 and the second motor 30, and may be changed to a large-capacity capacitor, for example.

  The accelerator opening sensor 203 detects the accelerator opening A (accelerator pedal operation amount by the user), and transmits the detection result to the ECU 200. The vehicle speed sensor 3 detects the vehicle speed V (the wheel speed can be used, and may be the second motor rotation speed NM2 or the like) and transmits the detection result to the ECU 200.

  Further, although not shown, the vehicle 1 includes an engine rotation speed NE, a first motor rotation speed NM1, a second motor rotation speed NM2, a temperature of the second motor 30, and a state of the battery 70 (current, voltage, temperature). For example, a plurality of sensors for detecting various physical quantities necessary for controlling the vehicle 1 are provided. These sensors transmit a detection result to ECU200.

  The ECU 200 is an electronic control unit incorporating a CPU (Central Processing Unit) and a memory (not shown). ECU 200 executes a predetermined calculation process based on information from each sensor and information stored in the memory, and controls each device of vehicle 1 based on the calculation result. ECU 200 controls vehicle driving force by controlling engine 10, PCU 60, and the like.

<Explanation of optimal fuel efficiency control and acceleration feeling control>
In a hybrid vehicle, the engine is controlled to operate at an efficient driving point in order to improve fuel efficiency. When controlled in this way, the engine speed does not react very sensitively to the user's accelerator pedal operation, the increase in vehicle speed, and the elapsed time of accelerator depression. Since user preferences vary, some users want a sense of acceleration in driving a vehicle.

  In a hybrid vehicle equipped with a continuously variable transmission, when a user requests acceleration, an acceleration feeling can be produced by increasing the engine rotation speed according to the increase in the vehicle speed (the user can feel the acceleration feeling). In the present specification, such control is referred to as rotational speed increase control or acceleration feeling effect control. When the output of the engine is insufficient or excessive with respect to the vehicle required power due to such an effect of acceleration, the output of the motor (motor power or regenerative power) can be adjusted so as to eliminate the excess or deficiency.

  FIG. 2 is a waveform diagram for explaining optimum fuel consumption control and acceleration feeling effect control. In FIG. 2, the vertical axis represents the engine speed NE, and the horizontal axis represents the elapsed time. Also, the broken line indicates the engine speed NEef when the optimal fuel efficiency control is executed, and the solid line indicates the engine speed NEac when the acceleration feeling effect control is executed.

  At time t1, the engine speed increases in response to the operation amount of the accelerator pedal exceeding the threshold value. At this time, when the acceleration feeling effect control is executed, the engine rotation speed NEac increases with time, but is controlled so that the increase rate is larger than the engine rotation speed NEef.

  This makes it easier for the user to feel that the engine sound changes, and to feel more acceleration as the vehicle speed and time elapse.

  When the acceleration feeling effect control is performed, the engine rotational speed NEac deviates from the optimum fuel efficiency rotational speed NEef at which the engine can output the vehicle required power most efficiently. Therefore, the excess or deficiency of the engine output is corrected by the motor output.

  Between times t1 and t2, since the engine output is insufficient, the shortage is compensated for by the motor output, so the discharge from the battery increases. On the other hand, between times t2 and t3, the excess output of the engine is regenerated by the motor and the battery is charged.

<Examination of applying acceleration feeling control to ASL control>
FIG. 3 is a diagram for explaining a problem in the case where the acceleration feeling effect control is applied to the ASL control. Referring to FIG. 3, when the ASL vehicle speed is set, when the ASL vehicle speed is reached (time t1), the vehicle speed does not increase any further even if the accelerator is depressed. This is because even if the operation amount of the accelerator pedal changes and the user accelerator opening Au changes, the control accelerator opening A is limited.

  However, in order to produce an acceleration feeling, the acceleration feeling effect control determines a command value for the engine speed based on the vehicle speed and the user accelerator opening Au. Therefore, when the driver returns the accelerator pedal a little as shown at times t14 to t15, the engine speed changes accordingly. At this time, since the control accelerator opening A is constant and the vehicle speed is also constant, there is a possibility that the user who recognizes that the vehicle speed is being restricted may feel uncomfortable.

  Further, during acceleration feeling effect control, normally, from time t11 to t13, the battery is discharged as insufficient engine power as shown at P1, and after time t13, the engine power is shown as shown at P3. As a result, the battery is charged. Therefore, although the balance is established by P1 and P3, during ASL control, as shown in P2, the vehicle speed is limited, and thus discharge may occur and excessive discharge may occur.

<Control of vehicle driving force>
FIG. 4 is a flowchart showing a flow of processing executed when ECU 200 controls the vehicle driving force. This flowchart is repeatedly executed at a predetermined calculation cycle ΔT.

  In step S10, the ECU 200 calculates a vehicle driving force (hereinafter referred to as “user required power”) Preq requested by the user based on the accelerator opening A and the vehicle speed V.

  In step S20, the ECU 200 calculates a power (hereinafter referred to as “battery required power”) PBreq necessary for charging or discharging the battery 70 based on the amount of power stored in the battery 70 (hereinafter also referred to as “battery SOC”). In the present embodiment, battery required power PBreq is a positive value when battery 70 needs to be charged, and a negative value when battery 70 needs to be discharged. Battery SOC is calculated by ECU 200 based on the state of battery 70.

  In step S30, the ECU 200 sets the total of the user required power Preq and the battery required power PBreq (total power required for the vehicle 1, that is, “vehicle required power”) as the engine required power PEreq.

  In step S40, ECU 200 determines whether or not accelerator opening A exceeds a threshold value. In this determination, the command engine operating point determined by the command engine rotational speed NEcom and the command engine torque TEcom is set by the optimum fuel efficiency control (the processing in steps S50 and S51 described later), or the acceleration feeling effect control (described later). This is a process for deciding whether to set in step S60 to step S67. The “threshold value” of this process can be set to any accelerator opening within a range of 50% to 70%, for example.

  If accelerator opening A does not exceed the threshold value (NO in step S40), ECU 200 sets the command engine operating point by optimal fuel efficiency control shown in steps S50 and S51. In the present embodiment, the optimal fuel consumption control is a process of setting the command engine operating point so that the engine 10 outputs the engine required power PEreq most efficiently.

  Specifically, the ECU 200 calculates the optimum engine operating point (optimum fuel consumption rotational speed NEef and optimum fuel consumption torque TEef) using the engine required power PEreq and the fuel consumption line (step S50), and the calculated optimum engine operating point. Is set as the command engine operating point (step S51). That is, ECU 200 sets optimal fuel efficiency rotational speed NEef to command engine rotational speed NEcom, and sets optimal fuel efficiency torque TEef to command engine torque TEcom.

  FIG. 5 is a diagram schematically showing a method for calculating the optimum fuel consumption rotational speed NEef and the optimum fuel consumption torque TEef by the optimum fuel consumption control. The fuel consumption line shown in FIG. 5 is an operation line obtained by connecting the operating points at which the engine 10 can be operated most efficiently (that is, with the optimum fuel consumption) using the engine speed NE and the engine torque TE as parameters. If the horizontal axis is the engine rotational speed NE and the vertical axis is the engine torque TE, the fuel efficiency line becomes a curve as shown in FIG. On the other hand, since the engine power PE is the product of the engine speed NE and the engine torque TE (PE = NE × TE), the curve where PE = PEreq (constant) is an inversely proportional curve as shown in FIG. Indicated by

  ECU 200 calculates optimal fuel efficiency rotational speed NEef and optimal fuel efficiency torque TEef from the intersection of the curve indicating the fuel efficiency line and the inversely proportional curve indicating PE = PEreq. By setting the optimal fuel efficiency rotational speed NEef and the optimal fuel efficiency torque TEef calculated as described above as the command engine operating point, the engine 10 can output the engine required power PEreq most efficiently.

  Returning to FIG. 4, when the accelerator opening A exceeds the threshold value (YES in step S40), the process of step S45 is executed. In step S45, it is determined whether the ASL vehicle speed is set and the current vehicle speed is the ASL vehicle speed. If the condition is satisfied in step S45, the process proceeds to step S50. On the other hand, if the condition is not satisfied in step S45, the process proceeds to step S60.

  ECU 200 sets the command engine operating point by the acceleration feeling effect control shown in steps S60 to S67. In the present embodiment, the acceleration feeling effect control is a time from the time when a vehicle speed increase, a change in the user accelerator opening Au, and an acceleration request are made to give the user a feeling of acceleration similar to that of a stepped transmission. This is a process for increasing the engine speed NE with at least one of the processes. Hereinafter, the acceleration feeling effect control is also referred to as a rotation speed increase process.

  Specifically, in step S60, the ECU 200 determines whether or not the current cycle is the first acceleration effect control. For example, when the accelerator opening A of the previous cycle is less than the threshold value, the ECU 200 determines that the current cycle is the first acceleration feeling effect control.

  When the current cycle is the first acceleration effect control (YES in step S60), ECU 200 calculates initial value NEini of the engine speed in step S61. The initial value NEini is calculated to be lower than the optimum fuel efficiency rotational speed NEef described in step S50. A method for calculating the initial value NEini will be described in detail later. In the subsequent step S62, the ECU 200 sets the initial value NEini to the command engine speed NEcom.

  On the other hand, when the current cycle is the second or later acceleration effect control (NO in step S60), ECU 200 determines in step S63 that the vehicle speed increase ΔV and the user accelerator opening increase amount ΔA from the previous cycle to the current cycle. , And the elapsed time (that is, the calculation cycle) ΔT, an increase rate of the engine rotation speed (an increase amount of the engine rotation speed during the elapsed time ΔT) ΔNE is calculated.

  Then, in step S64, the ECU 200 adds the value obtained by adding the increase rate ΔNE calculated in step S63 to the command engine speed NEcom of the previous cycle, as shown in the following equation (a), to the command engine speed of the current cycle. Calculated as NEcom.

NEcom = previous NEcom + ΔNE (a)
Therefore, during the acceleration feeling effect control, the command engine speed NEcom is gradually increased at the increase rate ΔNE. Thereby, a sense of acceleration can be given to the user.

  After the command engine speed NEcom is calculated in step S62 or step S64, the ECU 200 calculates a lower limit value NEmin and an upper limit value NEmax of the engine speed in step S65. The lower limit value NEmin and the upper limit value NEmax limit the fluctuation range of the engine rotational speed NE in order to prevent the first motor 20 and the power split device 40 from over-rotating and to prevent the battery 70 from being overcharged and discharged. It is a value to do.

  In step S66, the ECU 200 uses the lower limit value NEmin and the upper limit value NEmax calculated in step S65 to limit the command engine rotational speed NEcom calculated in step S62 or step S64 (hereinafter, “upper / lower limit guard process”). (Also called). In the upper / lower limit guard process, when the command engine speed NEcom falls below the lower limit value NEmin, the command engine speed NEcom is updated to the lower limit value NEmin. When the command engine speed NEcom exceeds the upper limit value NEmax, the command engine speed NEcom is updated to the upper limit value NEmax. When the command engine speed NEcom is a value between the lower limit value NEmin and the upper limit value NEmax, the command engine speed NEcom is maintained as it is.

  In step S67, the ECU 200 calculates the command engine torque TEcom using the command engine rotation speed NEcom and the fuel consumption line after the upper and lower limit guard processing.

  FIG. 6 is a diagram schematically illustrating a method for setting the command engine rotational speed NEcom and the command engine torque TEcom by the acceleration feeling effect control.

  In the first acceleration effect control, the command engine rotational speed NEcom is set to an initial value NEini that is lower than the optimal fuel efficiency rotational speed NEef, and the command engine torque TEcom corresponding to the initial value NEini is calculated using the fuel efficiency line. Accordingly, the engine power PE at the first time of the acceleration feeling effect control is a value smaller than the engine required power PEreq.

  In the second and subsequent acceleration effect control, the command engine speed NEcom is increased at an increase rate ΔNE, and the command engine torque TEcom is determined by the increased command engine speed NEcom and the fuel consumption line. Therefore, the engine power PE gradually increases.

  When the command engine rotational speed NEcom reaches the optimum fuel efficiency rotational speed NEef, the engine power PE matches the engine required power PEreq.

  Thereafter, when the command engine rotational speed NEcom further increases and becomes higher than the optimum fuel efficiency rotational speed NEef, the engine power PE becomes a value larger than the engine required power PEreq.

  As described above, the engine feeling PE may be excessive or insufficient with respect to the engine required power PEreq by performing the acceleration feeling effect control. This excess / deficiency is corrected by the output of the second motor 30 in the process of step S70 described later, so that the vehicle driving force requested by the user is realized.

  Returning to FIG. 4, when the command engine operating point is set by the optimal fuel efficiency control (steps S50 and S51) or the acceleration feeling effect control (steps S61 to S67), the ECU 200 determines in step S70 that the engine The first motor command torque TM1com and the second motor command torque TM2com are calculated so that the vehicle required power (= Preq + PBreq) is transmitted to the drive wheels 80 when the engine 10 is operated at the command engine operating point.

  As described above, during the optimal fuel consumption control, the engine power PE becomes the engine required power PEreq (see FIG. 5). On the other hand, during acceleration feeling effect control, the engine power PE may be excessive or insufficient with respect to the engine required power PEreq (see FIG. 6). In the process of step S70, the second motor command torque TM2com is calculated so that this excess / deficiency is corrected by the output (powering power or regenerative power) of the second motor.

  Specifically, when the engine power PE is less than the engine required power PEreq in the initial stage of the acceleration feeling effect control (that is, when NEcom <NEef), a positive torque (power running torque) that compensates for the power shortage is supplied to the second motor. The second motor command torque TM2com is calculated such that 30 is generated. In this case, electric power corresponding to the power shortage is discharged from the battery 70 to the second motor 30.

  On the other hand, when the engine power PE exceeds the engine required power PEreq as the acceleration feeling presentation control proceeds (that is, when NEcom> NEef), the negative torque (regenerative torque) that cancels the excess power is generated by the second motor 30. The second motor command torque TM2com is calculated so that. In this case, electric power corresponding to the excess power is generated by the second motor 30 and the battery 70 is charged.

  In subsequent step S71, ECU 200 determines whether or not MG1, MG2 temperature exceeds the threshold temperature. This process is a process for limiting the load factor in order to prevent overheating of the first motor 20 and the second motor 30. In step S71, TM1com and TM2com are limited as necessary. Thereafter, ECU 200 advances the process to step S80.

  In step S80, the ECU 200 causes the intake air amount, fuel injection amount, ignition timing, intake valve opening / closing timing, etc. of the engine 10 so that the engine 10 is operated at an operating point including the command engine rotational speed NEcom and the command engine torque TEcom. To control. Further, the ECU 200 controls the PCU 60 so that the first motor 20 outputs the first motor command torque TM1com and the second motor 30 outputs the second motor command torque TM2com.

FIG. 7 is an operation waveform diagram for explaining the operation when the control of the first embodiment is realized. Referring to FIG. 7, at time t21, acceleration feeling effect control is started in response to the increase in user accelerator opening Au (YES in step S40), and times t21 to t22 when the vehicle speed has not reached the ASL vehicle speed. During this period, the command rotational speed NEcom gradually increases to produce an acceleration feeling. During this time, since the engine speed is lower than that in the optimum fuel efficiency control, the battery is discharged as indicated by P1A.

  When the vehicle speed reaches the ASL vehicle speed at time t22 (YES in step S45), the control is switched from the acceleration feeling effect control to the optimum fuel consumption control. Thus, after time t22, control is performed so that the command rotational speed NEcom matches the optimum fuel efficiency rotational speed NEef.

  Therefore, since the processes of steps S63 and S64 in FIG. 4 are not executed from time t23 to t24, the change in the user accelerator opening Au affects the command rotational speed as indicated by the command value NEcom0 described in FIG. It is also suppressed.

  Note that the transition from the command rotational speed determined based on the acceleration feeling effect control at time t22 to the optimum fuel efficiency rotational speed NEef may be processed so as to gradually change as indicated by an arrow.

  As described above, in the first embodiment, the acceleration feeling effect control is canceled when the vehicle speed reaches the ASL vehicle speed and the vehicle speed does not increase any more. Therefore, excessive discharge after reaching the ASL vehicle speed, or the engine speed can be prevented from changing when the driver operates the accelerator pedal but the vehicle speed does not change, and the driver can be prevented from feeling uncomfortable. .

[Embodiment 2]
In the first embodiment, the driver feels uncomfortable by switching from the acceleration feeling effect control to the optimum fuel efficiency control, but the possibility that the engine speed suddenly changes at the time of switching remains. In the second embodiment, in order to solve such a problem, ECU 200 performs a process (hereinafter referred to as “correction process”) for correcting command engine rotation speed NEcom during acceleration feeling effect control during ASL setting.

  FIG. 8 is a flowchart showing a flow of processing executed when ECU 200 controls vehicle driving force in the second embodiment. This flowchart is repeatedly executed at a predetermined calculation cycle ΔT.

  The flowchart of FIG. 8 includes steps S61S, S63S, and S65S for executing correction processing instead of steps S61, S63, and S65 in the flowchart of the first embodiment shown in FIG. The other portions are the same as those described with reference to FIG. 4, and therefore description thereof will not be repeated here.

  In steps S61S, S63S, and S65S, as correction processing, (i) processing for correcting the initial value NEini of the engine rotational speed at the start of acceleration feeling control (hereinafter referred to as “initial value correction processing”), and (ii) acceleration. (Iii) processing for correcting the lower limit value NEmin of the engine rotational speed during acceleration feeling control (hereinafter referred to as “processing to correct the increase rate ΔNE of engine rotational speed during the feeling feeling control”). "Lower limit correction process").

  In the second embodiment, an example in which all the processes of steps S61S, S63S, and S65S are applied is shown. However, only one process or only two processes of steps S61S, S63S, and S65S are combined with the first embodiment. You may do it.

Hereinafter, these correction processes will be described in detail.
<< (i) Initial value correction process >>
FIG. 9 is a flowchart showing a detailed flow of the process for calculating the initial value NEini of the engine speed (the process in S61S in FIG. 8). During the calculation process of the initial value NEini, the above-described initial value correction process is performed.

  Referring to FIG. 9, first, in S61A, ECU 200 calculates a basic initial value NEini_base of the engine speed based on accelerator opening A and vehicle speed V. For example, in consideration of the acceleration feeling given to the user, ECU 200 calculates basic initial value NEini_base to a larger value as accelerator opening A is larger and vehicle speed V is higher. At this time, the basic initial value NEini_base is calculated so as to be higher than the command engine rotational speed NEcom of the previous cycle and lower than the optimum fuel efficiency rotational speed NEef of the current cycle. Note that the optimum fuel efficiency rotation speed NEef of the current cycle is calculated by the same process as the process of S50 of FIGS. 4 and 8 described above (see FIG. 5).

  In S61B, ECU 200 determines whether ASL control is applied, that is, whether the ASL vehicle speed is set.

  When ASL control is not applied (NO in S61B), ECU 200 sets basic initial value NEini_base to initial value NEini in S61C.

  On the other hand, when ASL control is applied (YES in S61B), ECU 200 determines in S61D whether or not the difference ΔVasl between the ASL vehicle speed and the current vehicle speed is smaller than a threshold value.

  If ΔVasl <threshold value is not satisfied in S61D (NO in S61D), ECU 200 sets basic initial value NEini_base to initial value NEini in S61C.

  On the other hand, if ΔVasl <threshold value is satisfied in S61D (YES in S61D), ECU 200 determines initial value NEini in accordance with function f1 (ΔVasl) in S61E.

  FIG. 10 is a diagram showing the relationship between the initial value NEini and ΔVasl determined in S61E of FIG. Referring to FIG. 10, when ΔVasl = 0, NEini = NEef is set. And NEini decreases as ΔVasl increases. The lower limit value of NEini may be NEini_base that is applied in S61C when ASL control is not applied.

  FIG. 11 is a diagram schematically showing the contents of the initial value correction processing. FIG. 12 is a diagram for explaining a change in the engine rotation speed when the initial value correction process is applied.

  Referring to FIGS. 11 and 12, when ASL control is not applied, or when the vehicle speed does not reach the ASL vehicle speed even during ASL control, initial value NEini is set to basic initial value NEini_base. On the other hand, when the vehicle speed reaches the ASL vehicle speed during the ASL control, the initial value NEini is set to a value closer to NEef than the basic initial value NEini_base. Therefore, since the engine power PE can be increased in advance to a value close to the engine required power PEreq from the first time (initial start) of the acceleration feeling effect control, the engine speed does not change suddenly at time t32, and the driver Can reduce the sense of incongruity.

<< (ii) Increase Rate Correction Process >>
FIG. 13 is a flowchart showing a detailed flow of a calculation process of the engine speed increase rate ΔNE (the process of S63 of FIG. 3). During the calculation process of the increase rate ΔNE, the above-described increase rate correction process is performed.

  In S63A, the ECU 200 increases the engine rotational speed increase rate (hereinafter referred to as “vehicle speed increase rate”) ΔNEv corresponding to the vehicle speed increase amount ΔV and the engine rotation speed increase rate (hereinafter referred to as “time increase increase”) corresponding to the elapsed time ΔT. ΔNEt) and an increase rate of the engine rotation speed corresponding to the user accelerator opening Au (hereinafter referred to as “acceleration-related increase rate”) ΔNEac are calculated.

  The ECU 200 calculates the vehicle speed corresponding increase rate ΔNEv to a larger value as the vehicle speed increase amount ΔV is larger, in order to give the user a greater feeling of acceleration as the vehicle speed increase amount ΔV is larger. In addition, the ECU 200 compares the time increase rate ΔNEt with a vehicle speed increase rate ΔNEv that is greater than the vehicle speed increase rate ΔNEv when the vehicle speed increase amount ΔV is substantially zero (when the vehicle speed V hardly increases on an uphill road or the like). It is calculated to a value smaller than the vehicle speed corresponding increase rate ΔNEv when the vehicle speed is high (when the vehicle speed V tends to increase on a flat road or a downhill road). Note that the time correspondence increase rate ΔNEt may be stored in advance as a fixed value.

  Further, the ECU 200 calculates the accelerator corresponding increase rate ΔNEac to be a larger value as the accelerator opening A is larger in order to give the user a feeling of acceleration as the accelerator opening A is larger.

  In S63B, as shown in the following equation (b), the ECU 200 calculates a value obtained by adding the accelerator corresponding increase rate ΔNEac to the larger increase rate of the vehicle speed corresponding increase rate ΔNEv and the time corresponding increase rate ΔNEt. The basic engine speed increase rate ΔNE_base is assumed.

ΔNE_base = max (ΔNEv, ΔNEt) + ΔNEac (b)
In S63C, ECU 200 determines whether ASL control is applied, that is, whether the ASL vehicle speed is set.

  When ASL control is not applied (NO in S63C), ECU 200 sets basic increase rate ΔNE_base to increase rate ΔNE in S63D.

  On the other hand, when ASL control is applied (YES in S63C), ECU 200 determines in S63E whether or not the difference ΔVasl between the ASL vehicle speed and the current vehicle speed is smaller than the threshold value.

  When ΔVasl <threshold value is not satisfied in S61D (NO in S61D), ECU 200 sets basic increase rate ΔNE_base to increase rate ΔNE in S63D.

  On the other hand, if ΔVasl <threshold value is satisfied in S63E (YES in S63E), ECU 200 determines increase rate ΔNE according to function f2 (ΔVasl) in S63F.

  FIG. 14 is a diagram showing the relationship between the increase rate ΔNE and ΔVasl determined in S63F of FIG. Referring to FIG. 14, the increase rate ΔNE is set to be smaller as ΔVasl is increased from ΔVasl = 0. Note that the value of ΔNE (the lower limit value of ΔNE) when ΔVasl is greater than or equal to a predetermined value may be set to, for example, the basic increase rate ΔNE_base or max (ΔNEv, ΔNEt).

  FIG. 15 is a diagram for explaining a change in the engine rotation speed when the increase rate correction process is applied. Referring to FIG. 15, during the ASL control, at times t41 to t42, the engine speed command is set so that the increase rate (slope) of the engine speed increases as the difference ΔVasl between the vehicle speed and the ASL vehicle speed decreases. The value NEcom is determined.

  Therefore, since NEcom has approached NEef by the time t42, the engine rotational speed does not change more rapidly than the time t22 shown in FIG. 7 at time t42, and the uncomfortable feeling given to the driver can be reduced.

<< (iii) Lower limit correction process >>
FIG. 16 is a flowchart showing a detailed flow of the calculation process of the lower limit value NEmin of the engine rotation speed (part of the process of S65S of FIG. 8). During the calculation process of the lower limit value NEmin, the lower limit correction process described above is performed.

  In S65A, ECU 200 calculates a basic lower limit value NEmin_base of the engine speed.

  For example, ECU 200 calculates an allowable engine speed region that satisfies all of the following requirements 1 to 3, and sets the lower limit value and the upper limit value of the calculated allowable engine speed region as a basic lower limit value NEmin_base and a basic upper limit value, respectively. Let it be NEmax_base.

  (Requirement 1) The rotational speed of the first motor 20 is included in the allowable rotational speed region in the structure of the motor.

  (Requirement 2) The rotational speed of the pinion gear of the power split device 40 is included in the allowable rotational speed region determined by the structure of the power split device 40.

  (Requirement 3) The power charged in the battery 70 (hereinafter referred to as “battery charging power Pin”) is less than the allowable charging power Win determined by the SOC and temperature of the battery 70 and is discharged from the battery 70 (hereinafter referred to as “battery charging power Pin”). Discharge power Pout ”) is less than the allowable discharge power Wout determined by the SOC and temperature of the battery 70.

  In S65B, the ECU 200 determines whether the ASL control is applied, that is, whether the ASL vehicle speed is set.

  When ASL control is not applied (NO in S65B), ECU 200 sets basic lower limit value NEmin_base to lower limit value NEmin in S65C.

  On the other hand, when ASL control is applied (YES in S65B), ECU 200 determines in S65D whether or not the difference ΔVasl between the ASL vehicle speed and the current vehicle speed is smaller than the threshold value.

  When ΔVasl <threshold value is not satisfied in S65D (NO in S65D), ECU 200 sets basic lower limit value NEmin_base to lower limit value NEmin in S65C.

  On the other hand, if ΔVasl <threshold value is satisfied in S65D (YES in S65D), ECU 200 determines lower limit value NEmin in S65E according to function f3 (ΔVasl).

  As for the upper limit value NEmax, the basic upper limit value NEmax_base may be used as it is, or some correction may be performed.

  FIG. 17 is a diagram showing the relationship between the lower limit value NEmin and ΔVasl determined in S65E of FIG. Referring to FIG. 17, when ΔVasl = 0, NEmin = NEef is set. Then, as ΔVasl increases, NEmin decreases. The lower limit value of NEini may be NEmin_base applied in S65C when ASL control is not applied.

  FIG. 18 is a diagram for explaining a change in the engine rotation speed when the lower limit correction process is applied. Referring to FIG. 18, during ASL control, at times t51 to t52, it is determined that lower limit value NEmim of engine rotational speed approaches NEef as time difference ΔVasl between vehicle speed and ASL vehicle speed decreases, and from time t52 to t Since the engine speed is limited by NEmin at 53, the engine speed command value NEcom gradually approaches NEef.

  Accordingly, since NEcom is close to NEef by time t53, the engine speed does not change more rapidly than that shown at time t22 in FIG. 7 at time t53, and the uncomfortable feeling given to the driver can be reduced.

  As described above, in the second embodiment, as in the first embodiment, the acceleration feeling effect control is canceled when the vehicle speed reaches the ASL vehicle speed and the vehicle speed does not increase any more. Therefore, excessive discharge after reaching the ASL vehicle speed, or the engine speed can be prevented from changing when the driver operates the accelerator pedal but the vehicle speed does not change, and the driver can be prevented from feeling uncomfortable. .

  In addition, in the second embodiment, since a sudden change in the engine rotation speed at the time of releasing the acceleration feeling effect control can be suppressed, the uncomfortable feeling given to the driver can be further reduced.

<Modification>
In addition, this Embodiment can also be changed as follows, for example.

  (1) In the above-described embodiment, the case has been described in which the three correction processes of the initial value correction process, the increase rate correction process, and the upper and lower limit correction process are performed. However, it is not necessarily limited to performing all three correction processes.

  For example, any one of the three correction processes described above may be performed, or any two correction processes may be performed. Further, the three correction processes or any two of the correction processes may be properly used depending on the situation.

  Further, after configuring the three correction processes or any two of the correction processes, each correction process may be executed with priority. For example, the increase rate correction process and the upper and lower limit value correction process may be executed, and the increase rate correction process may be performed with priority over the upper and lower limit value correction process. In this way, first, the engine speed NE can be corrected gently by the increase rate correction process, and when further correction is required, the engine speed NE can be corrected rapidly by the upper / lower limit value correction process.

  (2) Although the case where the vehicle driving force is controlled based on the vehicle required power has been described in the above-described embodiment, the vehicle driving force may be controlled based on the torque required for the vehicle.

  Finally, the present embodiment will be summarized with reference to FIG. 1 again. The vehicle 1 according to the embodiment includes an engine 10, a continuously variable transmission (provided by the first motor 20 and the power split device 40) provided between the engine 10 and the drive wheels 80, And a control device 200 for controlling the step transmission. The control device 200 controls fuel consumption priority engine control that gives priority to fuel efficiency, and rotational speed increase control (acceleration feeling effect control) that increases the rotational speed of the engine 10 in accordance with at least one of a vehicle speed increase, an accelerator opening increase, and a lapse of time. ) And vehicle speed limit control (ASL control) for limiting the vehicle speed to the upper limit vehicle speed is executed. When the vehicle speed reaches the upper limit vehicle speed (ASL vehicle speed) during execution of the rotation speed increase control, the control device 200 cancels the rotation speed increase control and shifts to the fuel efficiency priority engine control (see t22 in FIG. 7). ).

  When the vehicle speed V reaches the upper limit vehicle speed (ASL vehicle speed), the vehicle speed V does not increase any further. In this case, if the engine speed NE increases, the driver may feel uncomfortable. In addition, when the driver recognizes that the vehicle speed V is limited, the accelerator opening Au is changed even though the accelerator opening Au is changed, even though the vehicle speed V is limited to a constant value. If only the engine speed NE changes in response to this, the driver may still feel uncomfortable. As indicated by t22 in FIG. 7, when the vehicle speed V reaches the upper limit vehicle speed (ASL vehicle speed), the rotational speed increase control is canceled, so that such a sense of incongruity can be reduced.

  Preferably, vehicle 1 is a hybrid vehicle that outputs the driving force of the vehicle by the power of engine 10 and the power of motor 30 driven by the electric power from battery 70. During execution of the rotational speed increase control, the control device 200 prioritizes the command engine rotational speed NEcom as the difference ΔVasl between the vehicle speed and the upper limit vehicle speed decreases before the vehicle speed V reaches the upper limit vehicle speed (ASL vehicle speed). The engine speed is increased so as to approach the engine rotation speed NEef determined when engine control is applied.

  Preferably, as shown in FIGS. 9 to 12, when the control device 200 starts executing the rotation speed increase control, the smaller the difference between the vehicle speed and the upper limit vehicle speed is, the smaller the vehicle speed reaches the upper limit vehicle speed. Then, the initial command value of the engine speed is set to a large value.

  Preferably, as shown in FIGS. 13 to 15, the control device 200 performs the difference between the vehicle speed V and the upper limit vehicle speed (ASL vehicle speed) before the vehicle speed reaches the upper limit vehicle speed during the rotation speed increase control. Is smaller, the change rate ΔNE of the command engine speed NEcom is increased.

  Preferably, as illustrated in FIGS. 16 to 18, the control device 200 performs the difference between the vehicle speed and the upper limit vehicle speed before the vehicle speed V reaches the upper limit vehicle speed (ASL vehicle speed) during the rotation speed increase control. Is smaller, the lower limit value NEmin of the command engine rotation speed NEcom is set to a larger value to limit the command engine rotation speed NEcom.

  When canceling the rotation speed increase control, if the engine rotation speed after shifting to fuel efficiency priority engine control deviates from the current engine rotation speed, the engine rotation speed will change suddenly, giving the driver a sense of incongruity. End up. According to the above control, the control is performed so that the engine speed approaches the command value of the engine speed after the rotational speed increase control is canceled as the vehicle speed approaches the upper limit vehicle speed, so that a sudden change in the engine speed can be suppressed.

  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, 3 vehicle speed sensor, 10 engine, 16 drive shaft, 20 first motor, 30 second motor, 40 power split device, 58 speed reducer, 70 battery, 80 drive wheel, 200 control device, 203 accelerator opening sensor.

Claims (5)

A vehicle,
Engine,
A continuously variable transmission provided between the engine and the drive wheel;
A control device for controlling the engine and the continuously variable transmission,
The control device performs any one of fuel efficiency priority engine control for giving priority to fuel efficiency and rotational speed increase control for increasing the rotational speed of the engine in accordance with at least one of a vehicle speed increase, an accelerator opening increase, and a lapse of time. And performing vehicle speed limit control to limit the vehicle speed to the upper limit vehicle speed,
When the vehicle speed reaches the upper limit vehicle speed during execution of the rotation speed increase control, the control device releases the rotation speed increase control and shifts to the fuel efficiency priority engine control. The vehicle is a hybrid vehicle that outputs a driving force of the vehicle by power of the engine and power of a motor driven by electric power from a battery,
The control device, while executing the rotational speed increase control, before the vehicle speed reaches the upper limit vehicle speed, the smaller the difference between the vehicle speed and the upper limit vehicle speed, the more the commanded engine rotational speed is controlled by the fuel efficiency priority engine control. The vehicle according to claim 1, wherein the vehicle is increased so as to approach an engine speed determined when applied. The vehicle is a hybrid vehicle that outputs a driving force of the vehicle by power of the engine and power of a motor driven by electric power from a battery,
When starting execution of the rotation speed increase control, the control device increases the initial command value of the engine rotation speed as the difference between the vehicle speed and the upper limit vehicle speed decreases before the vehicle speed reaches the upper limit vehicle speed. The vehicle according to claim 1, wherein the vehicle is set to a value. The vehicle is a hybrid vehicle that outputs a driving force of the vehicle by power of the engine and power of a motor driven by electric power from a battery,
The control device increases the change rate of the command engine rotation speed as the difference between the vehicle speed and the upper limit vehicle speed is smaller before the vehicle speed reaches the upper limit vehicle speed during the rotation speed increase control. The vehicle according to claim 1. The vehicle is a hybrid vehicle that outputs a driving force of the vehicle by power of the engine and power of a motor driven by electric power from a battery,
The controller increases the lower limit value of the command engine rotational speed as the difference between the vehicle speed and the upper limit vehicle speed is smaller before the vehicle speed reaches the upper limit vehicle speed during execution of the rotational speed increase control. The vehicle according to claim 1, wherein the vehicle is set to limit a command engine rotation speed.

Images