JP4963104B2 - Control method of hybrid vehicle - Google Patents

Description

  The present invention relates to a control method for a hybrid vehicle that includes an engine and a motor, and adds an output from the engine when an output torque necessary for traveling of the vehicle is larger than an output of the motor.

In recent years, various hybrid vehicles that have driving means including an engine and a motor and have improved fuel efficiency have been considered. As an example of such a hybrid vehicle, it has been considered to perform control to reduce the rate of output supplied from the motor and increase the rate of output supplied from the engine as the charge amount of the battery decreases ( For example, see Patent Document 1).
JP 2002-120602 A

  However, in such a configuration, the output from the motor decreases as the charge amount decreases, so the output from the engine increases when the accelerator operation amount is kept constant. At this time, although the accelerator is not depressed for the purpose of accelerating, the sound from the engine becomes loud, which may cause the driver and passengers to feel uncomfortable.

  The present invention is configured to solve such problems.

  In other words, the hybrid vehicle control method according to the present invention is used in a hybrid vehicle having an engine, power storage means capable of storing electric power, and a motor that operates with the electric power stored in the power storage means. When the change in the accelerator operation amount is detected when the charge amount of the power storage means is equal to or less than the predetermined value while the vehicle is traveling using the vehicle, the output from the motor is reduced to reduce the output required for vehicle travel. If the difference between the two is output from the engine and no change in the accelerator operation amount is detected, control is performed to maintain the output from the motor.

  If this is the case, as long as the accelerator operation amount does not change, the engine output to compensate for the decrease in power generation due to battery consumption will not be increased, so it is possible to suppress the occurrence of an uncomfortable situation for drivers and other passengers. Can do.

  “Detecting a change in accelerator operation amount” means, for example, detecting an accelerator operation amount every predetermined time, and storing the detected accelerator operation amount sequentially, so that the accelerator operation related to the two most recent detections is detected. This is a concept including the overall detection of a change in the accelerator operation amount from a state in which the accelerator operation amount is kept constant, such as determining that the amount difference is equal to or greater than a predetermined value.

  The “accelerator operation amount” is not limited to the accelerator pedal, and is a concept that indicates the entire operation amount of a part of the vehicle that changes the operation amount when accelerating and decelerating.

  According to the hybrid vehicle control method of the present invention, when the charge amount of the power storage means is equal to or less than a predetermined value, the accelerator operation amount is increased while increasing the engine output to compensate for the decrease in the power generation amount due to battery consumption. Since the engine output is not increased unless changes occur, it is possible to suppress the occurrence of a situation in which the driver or other passengers feel uncomfortable.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the hybrid vehicle of this embodiment has an engine 1 and a motor generator 2 that generate a driving force required for traveling, a driving shaft 4 connected to driving wheels 3, and a driving force of the motor generator 2. A first transmission system 5 that transmits to the drive shaft 4, a second transmission system 6 that transmits the driving force of the engine 1 to the drive shaft 4, a motor control device 7 that controls the rotation and power generation of the motor generator 2, and the engine 1 And a central control device 8 for controlling the operation of the system. Further, a motor battery 9 as a power storage means as a power source of the motor generator 2, and a vehicle outlet, for example, a household outlet, that is, a power line, or a separately provided solar cell for charging the motor battery 9 while parking or the like are representative. The battery charger 10 is supplied with power from an external power source or the like. In addition, an engine battery 11 serving as a power source for the headlamp and the central controller 8 and an alternator 12 for charging the engine battery 11 are also provided.

  The engine 1 is, for example, a gasoline engine or a diesel engine, and is provided with an electric throttle 15 in the intake system. The engine 1 transmits a driving force to a drive shaft via a transmission 6a constituting the second transmission system 6 and a clutch 6b which is a joint device disposed between the transmission 6a and the internal combustion engine 1. 4 is output.

  The motor generator 2 can generate a driving force necessary for traveling, that is, functions as a motor in claims, and also functions as a generator by being driven by the engine 1 or driving wheels 3 and performing regenerative operation. The motor generator 2 is selectively connected to the drive shaft 4 via the first transmission system 5.

  The first transmission system 5 includes a transmission gear device and a clutch. When the engine 1 drives the drive wheel 3, the clutch is disconnected when the rotation speed of the drive shaft 4 exceeds the allowable limit rotation speed. It is to be controlled. In this case, the clutch may be either hydraulic or electromagnetic. As long as the first transmission system 5 can transmit the driving force of the motor generator 2 to the drive shaft 4, the configuration is not particularly limited to that described above, and the configuration of only the rotary shaft or the rotation The structure which combined the axis | shaft and the gear may be sufficient.

  The second transmission system 6 includes the transmission 6a and the clutch 6b described above, and transmits the driving force of the engine 1 to the drive shaft 4 via the transmission 6a by connecting the clutch 6b. . The transmission 6a is an automatic transmission that changes the gear ratio according to the engine speed. The clutch 4 can connect and disconnect between the input side rotating shaft 6c of the transmission 6a and the engine 1. The drive shaft 4 is connected to the output side rotation shaft of the transmission 6a. As the clutch 6b, an existing forward clutch may be substituted. Such a forward clutch is connected when the transmission 6a is operated at least in the D range, and therefore does not require any special control for the intermittent operation.

  The motor control device 7 controls the electric power supplied to the motor generator 2 so that the motor generator 2 outputs a driving force necessary for traveling. The motor control device 7 charges the motor battery 9 with electric power output from the motor generator 2 that is regeneratively operated when the vehicle is traveling at a reduced speed. Such a motor control device 7 includes, for example, an inverter or a DC-DC converter.

  On the other hand, as schematically shown in FIG. 2, the central control unit 8 is mainly configured by a microcomputer system including a central processing unit 16, a storage unit 17, an input interface 18, and an output interface 19. Has been. The input interface 18 includes an accelerator operation amount signal a output from the accelerator state sensor 21 for detecting the operation amount θ of the accelerator pedal 20, a vehicle speed signal b output from the vehicle speed sensor 22 for detecting the vehicle speed v, A throttle opening signal c indicating the opening of the electric throttle 15, a motor temperature signal d indicating the temperature Tm of the motor generator 2 output from the motor temperature sensor 23, and a charge amount E of the motor battery 9 output from the motor battery 9 Is input at least as a charge amount signal e. On the other hand, from the output interface 19, the opening degree control signal g for the electric throttle 15, the reduction ratio control signal h for the transmission 6 a, and the motor output amount or power generation amount for the motor control device 7. The output control signal i shown is output at least.

  Furthermore, in the present embodiment, a required output determination program for obtaining an output (hereinafter referred to as required output RT) required for traveling of the vehicle from the accelerator operation amount θ indicated by the accelerator operation amount signal a and the vehicle speed v indicated by the vehicle speed signal b, and the motor battery 9 The motor output determination program for obtaining the maximum output possible output MT of the motor generator 2 using the charge amount parameter E1 which is a value corresponding to the charge amount E of the motor generator 2, and the maximum output possible output MT of the motor generator 2 is smaller than the required output RT In this case, an engine output determination program for calculating the engine output ET is incorporated in the control device 11. Here, in the motor output determination program, when the charge amount E of the motor battery 9 is less than the predetermined value Es and the change in the accelerator operation amount θ is not detected, the engine output ET without the accelerator operation is detected. In order to prevent an increase in the charging amount, control is performed such that the charge amount parameter E1 is not changed. This control corresponds to “the control for maintaining the output from the motor when the change in the accelerator operation amount is not detected when the charge amount of the power storage means is equal to or less than the predetermined value” in the claims. The required output determination program, the motor output determination program, and the engine output determination program are started each time an ignition switch (not shown) is turned on.

  Here, the control described above causes the vehicle to travel mainly by the electric power stored in the motor battery 9 and travels only by the output from the motor generator 2 as the charge amount E of the motor battery 9 decreases → the engine 1 and the traveling by the output from the motor generator 2 (hybrid traveling) → the traveling by only the output from the engine 1 is sequentially performed. As the predetermined value Es, for example, a battery capacity required to travel about the average travel distance of the user once, a half of the maximum battery capacity of the motor battery 9, or the like can be considered. Further, the traveling by only the output from the engine 1 is performed when the charge amount E is equal to or less than a predetermined lower limit Em. Here, the predetermined lower limit value Em is set to a value slightly higher than the minimum charge amount E for preventing the performance of the motor battery 9 from being deteriorated.

  Further, the accelerator operation amount θ is measured every predetermined time, for example, every 0.1 second to obtain the change speed of the accelerator operation amount θ, and the accelerator operation amount θ is stored at least a predetermined number of times, for example, 10 times. A quantity measurement program is also built in the control device 11.

  The accelerator operation amount measurement program is activated every time an ignition switch (not shown) is turned on, and is executed in parallel with the request output determination program, the motor output determination program, and the engine output determination program.

  Here, the control procedure by the required output determination program, motor output determination program, engine output determination program, and accelerator operation amount measurement program will be described below with reference to FIG. 3 which is a flowchart.

  First, in step S1, the vehicle speed signal b, accelerator operation amount signal a, motor temperature signal d, and battery charge amount signal e are received. Then, the process proceeds to step S2.

  Thereafter, in step S2, the required output RT is calculated by referring to the required output map using the vehicle speed v indicated by the vehicle speed signal b and the accelerator operation amount θ indicated by the accelerator operation amount signal a as parameters. Thereafter, the process proceeds to step S3. Here, the required output map is obtained by storing the required output RT for a typical vehicle speed v and accelerator operation amount θ in a predetermined area of the storage device 10 in the control device 8. The required output RT in the required output map is obtained in advance based on experiments. The actual required output RT is calculated by interpolation calculation using the vehicle speed v and the accelerator operation amount θ as parameters.

  In step S3, it is determined whether or not the charge amount E of the battery 5 indicated by the charge amount signal e is below a predetermined value Es. If the charge amount E of the battery 5 is below the predetermined value Es, the process proceeds to step S4. Otherwise, the process proceeds to step S5.

  In step S4, it is determined whether or not a change in the accelerator operation amount θ is detected. If a change in the accelerator operation amount θ is detected, the process proceeds to step S5. Otherwise, the process proceeds to step S6. Specifically, the accelerator operation amount θ stored by the accelerator operation amount measurement program is read out at the time of executing step S4 and at the time before the predetermined time, and the difference between them is a predetermined value. In the above case, it is determined that the change in the accelerator operation amount θ is detected. The predetermined value may be set arbitrarily.

  In step S5, the charge amount E of the battery 5 indicated by the charge amount signal e is set as the charge amount parameter E1, and this charge amount is stored as the past charge amount E0, and the process proceeds to step S7.

  In step S6, the stored past charge amount E0 is set as the charge amount parameter E1, and the process proceeds to step S7.

  In step S7, the output possible maximum output MT is calculated with reference to the motor maximum output map using the temperature Tm of the motor generator 2 indicated by the motor temperature signal d and the charge amount parameter E1 as parameters. Thereafter, the process proceeds to step S8. Here, the motor maximum output map is obtained by storing the maximum outputable output MT for a typical motor temperature Tm and charge amount E in a predetermined area of the storage device 10 in the control device 8. The maximum output possible output MT in the motor maximum output map is obtained in advance based on experiments. In this motor maximum output map, as the motor temperature Tm increases and as the charge amount parameter E1 decreases, the maximum output possible output MT decreases. In particular, when the charge amount parameter E1 is equal to or less than the predetermined lower limit Em, the maximum output possible output MT is set to zero. The actual maximum output possible output MT is calculated by interpolation calculation using the motor temperature Tm and the charge amount parameter E1 as parameters.

  In step S8, it is determined whether or not the output required for traveling, that is, the required output RT is greater than the maximum output possible output MT. If the requested output RT is greater than the maximum output possible output MT, the process proceeds to step S9. Otherwise, the process proceeds to step S11.

  In step S9, operation control for operating the motor generator 2 at the maximum output possible output MT is performed. Thereafter, the process proceeds to step S10.

  In step S10, the engine output ET is calculated by the following equation (1), and then the process returns to step S1.

ET = RT-MT (1)
In step S11, the torque of the motor generator 2 is determined using the required output RT and the rotation speed of the motor generator 2 as parameters, and then the process proceeds to step S12.

  In step S12, operation control of the motor generator 2 is performed. That is, output control signal i corresponding to the torque of motor generator 2 determined in step S11 is output to inverter 4. Then, the process returns to step S1.

  Here, the operation of the control by the required output determination program, the motor output determination program, and the engine output determination program will be described with reference to FIG. Note that regenerative power generation is not performed in the time period shown in FIG.

  In the time zone T1, the charge amount E is larger than the predetermined value Es, and the required output RT is smaller than the maximum output possible output MT. Therefore, the control of the steps S1, S2, S3, S5, S7, S8, S11, and S12 is sequentially performed. Then, the process returns to step S1. That is, the vehicle travels using only the driving force from the motor generator 2.

  In the time zone T2, since the charge amount E is smaller than the predetermined value Es and there is no change in the accelerator operation amount θ, the steps S1, S2, S3, S4, S6, S7, S8, S11, and S12 are sequentially performed. Thereafter, the process returns to step S1. That is, in this time zone, the charge amount E in the immediately preceding time zone T1 is a value corresponding to the maximum output possible output MT that is larger than the required output RT, so the charge amount E immediately before entering this time zone T2 is the charge amount. The maximum output MT that can be output is determined as the parameter E1. That is, since it is determined in step S8 that the maximum output possible output MT is larger than the required output RT, the vehicle travels using only the driving force from the motor generator 2. Therefore, the engine output ET is not increased in this time zone.

  In the time zone T3, the charge amount E is smaller than the predetermined value Es and the accelerator operation amount θ is changed. Therefore, the control of the steps S1, S2, S3, S4, S6, S7, S8, S9, and S10 is sequentially performed. Then, the process returns to step S1. That is, during this time period, the output from the motor generator 2 (maximum output possible output MT) is decreased in response to the decrease in the charge amount E, the engine output is increased, the driving force from the engine 1 and the motor generator 2 are increased. The vehicle travels using both of the driving force from.

  In the time zone T4, the charge amount E is smaller than the predetermined value Es and there is no change in the accelerator operation amount θ. Therefore, the control of the steps S1, S2, S3, S4, S5, S7, S8, S9, and S10 is sequentially performed. Thereafter, the process returns to step S1. That is, in this time zone T4, the maximum output is determined by using the charge amount E immediately before entering this time zone T4 as the charge amount parameter E1, so that the maximum possible output of the motor generator 2 as the charge amount E during traveling decreases. The ratio with the engine output ET is kept constant without reducing MT.

  Therefore, even if the charge amount E is smaller than the predetermined value Es, the maximum output possible output MT does not decrease unless the accelerator operation amount θ is changed so as to perform acceleration or the like. Therefore, the output from the motor generator 2 is reduced. To compensate, the engine output ET is not increased.

  That is, by adopting the hybrid vehicle control method according to the present embodiment, even when the charge amount E of the motor battery 9 decreases to a predetermined value Es or less, the change amount of the accelerator opening θ exceeds the predetermined value. As long as the vehicle does not operate, that is, as long as the vehicle continues to run stably, the engine output ET is not increased to compensate for the decrease in power generation due to battery consumption. And the occurrence of a situation in which the driver or other passengers feel uncomfortable can be suppressed.

  If the predetermined value Es is a battery capacity necessary to travel about the average travel distance of the user once, it is possible to travel mainly using the electric power charged in the motor battery 9. . On the other hand, if the predetermined value Es is about half of the maximum battery capacity of the motor battery 9, control as a general hybrid vehicle can be performed on the engine 1 and the motor generator 2.

  The present invention is not limited to the embodiment described above.

  For example, instead of using the motor generator as in the above-described embodiment, a motor that performs torque assist and a generator that performs regenerative power generation are provided separately, and each of them is connected to the output shaft of the engine. Good.

  The mode of connection between the engine and the motor (including the motor generator) is not limited to that described in the above-described embodiment. For example, the output shaft of the engine and the output shaft of the motor are connected by a chain, a belt, a gear, or the like. You may employ | adopt the thing of the aspect connected.

  Further, in the above-described embodiment, the hybrid running is performed when the required output RT exceeds the maximum output possible output MT of the motor generator 2 at the time when the required output RT is calculated. Even when the maximum possible output MT does not exceed the maximum possible output MT, if the required output RT exceeds the maximum efficiency output, which is the output that maximizes the operation efficiency of the motor generator 2, the motor generator 2 outputs only the maximum efficiency output. Alternatively, control may be performed to determine the difference between the required output RT and the maximum efficiency output as the engine output.

  In addition, when the charge amount E of the motor battery 9 (power storage means) in the above-described embodiment is equal to or less than the second predetermined value Et below the predetermined value Es, regardless of whether or not the accelerator operation amount θ has changed, Control for reducing the output MT of the motor generator 2 by reflecting the decrease in the charge amount E may be performed.

  Furthermore, in a hybrid vehicle or the like that runs at a motor speed below a predetermined speed and that runs at a higher speed, a control that gradually increases the share of the engine output as the charge amount of the power storage means decreases, or a control that starts the engine You may apply this invention when performing. That is, the control for increasing the engine output or the control for starting the engine may be performed only when the accelerator operation amount is changed.

  A procedure for performing such control will be described below with reference to FIG. 3 which is a flowchart.

  First, in step S101, input of the vehicle speed signal b, accelerator operation amount signal a, motor temperature signal d, and battery charge amount signal e is accepted. Then, the process proceeds to step S102.

  Thereafter, in step S102, the required output RT is calculated with reference to the required output map using the vehicle speed v indicated by the vehicle speed signal b and the accelerator operation amount θ indicated by the accelerator operation amount signal a as parameters. Thereafter, the process proceeds to step S3. Here, the required output map is obtained by storing the required output RT for a typical vehicle speed v and accelerator operation amount θ in a predetermined area of the storage device 10 in the control device 8. The required output RT in the required output map is obtained in advance based on experiments. The actual required output RT is calculated by interpolation calculation using the vehicle speed v and the accelerator operation amount θ as parameters.

  In step S103, it is determined whether or not the charge amount E of the battery 5 indicated by the charge amount signal e is below a predetermined value Es. In this aspect, the predetermined value Es is set to about 85% of the full charge amount. If the charge amount E of the battery 5 is below the predetermined value Es, the process proceeds to step S104. Otherwise, the process proceeds to step S105.

  In step S104, it is determined whether or not a change in the accelerator operation amount θ is detected. If a change in the accelerator operation amount θ is detected, the process proceeds to step S105. Otherwise, the process proceeds to step S106. Specifically, out of the accelerator operation amount θ stored by the accelerator operation amount measurement program, the one at the time of executing step S104 and the time before the predetermined time are read, and the difference between them is a predetermined value. In the above case, it is determined that the change in the accelerator operation amount θ is detected. The predetermined value may be set arbitrarily.

  In step S105, the charge amount E of the battery 5 indicated by the charge amount signal e is set as the charge amount parameter E1, and this charge amount is stored as the past charge amount E0, and the process proceeds to step S107.

  In step S106, the stored past charge amount E0 is set as the charge amount parameter E1, and the process proceeds to step S107.

  In step S107, an output MMT supplied from the motor is calculated with reference to the output sharing ratio map using the charge amount parameter E1 as a parameter. Thereafter, the process proceeds to step S108. Here, the output sharing ratio map is obtained by storing the ratio of the output MMT supplied from the motor to the required output RT in the representative charge amount E in a predetermined area of the storage device 10 in the control device 8. The said ratio is calculated | required beforehand based on experiment, for example so that the sum total of fuel cost and electric power cost may be minimized. Further, in this output sharing ratio map, the ratio of the output MMT supplied from the motor to the required output RT is small. In particular, when the charge amount parameter E1 is equal to or less than the predetermined lower limit Em, the maximum output possible output MT is set to zero. The ratio of the output MMT supplied from the actual motor to the required output RT is calculated by interpolation calculation using the charge amount parameter E1 as a parameter.

  In step S108, operation control for operating the motor generator 2 at the output MMT is performed. Thereafter, the process proceeds to step S109.

  In step S109, the engine output ET is calculated by the following equation (2), and then the process returns to step S101.

ET = RT-MMT (2)
Even when the above-described control is performed, the control for increasing the engine output ratio or the control for starting the engine is performed only when the accelerator operation amount has changed, so even though the accelerator operation is not performed. Therefore, the engine output is increased and the engine noise is increased, so that it is possible to suppress the occurrence of an uncomfortable feeling for the driver or the like.

  Then, optimal fuel consumption control for controlling the throttle opening and the reduction ratio may be separately performed so as to operate the engine so as to obtain the engine output with the highest fuel efficiency.

  In addition, various changes may be made without departing from the spirit of the present invention.

Schematic which shows the vehicle which concerns on 1st embodiment of this invention. Schematic which shows the control apparatus which concerns on the same embodiment. The flowchart which shows the process which the control apparatus which concerns on the same embodiment performs. Action | operation explanatory drawing which concerns on the same embodiment. The flowchart which shows the process which the control apparatus which concerns on other embodiment of this invention performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Motor generator (motor)
8 ... Central controller 9 ... Motor battery (power storage means)

Claims (1)

Used in a hybrid vehicle having an engine, power storage means capable of storing electric power, and a motor operated by the electric power stored in the power storage means,
When traveling using the driving force from the motor and the charge amount of the power storage means is below a predetermined value,
When a change in the amount of accelerator operation is detected, the output from the motor is reduced and the difference from the output required for vehicle travel is output from the engine.
A control method for a hybrid vehicle, characterized in that control for maintaining output from a motor is performed when a change in accelerator operation amount is not detected.

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