JP2018135048A - Power control method and power control device of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power control method and a power control device of a hybrid vehicle which can effectively absorb torque variation of an engine while suppressing the deterioration of an energy efficiency.SOLUTION: A power control device of a hybrid vehicle estimates an average torque output from an engine, estimates a torque variation component of the torque output from the engine, sets a counter torque suppressing the estimated torque variation component, and has a PCM (power control module) which controls an electric motor so that the electric motor outputs the set counter torque. The PCM sets the counter torque so that when a revolution speed of the engine is constant and the average torque output from the engine is equal to a predetermine value, the absolute value of the counter torque becomes its maximum.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a power control method and a power control apparatus for a hybrid vehicle, and more particularly, to an internal combustion engine, a power transmission mechanism that transmits the power of the internal combustion engine to driving wheels, and outputs power to the power transmission mechanism connected to the internal combustion engine. The present invention relates to a power control method and a power control apparatus for a hybrid vehicle including a possible electric motor.

Conventionally, in order to improve the operability and ride comfort of an internal combustion engine (hereinafter referred to as an “engine”) such as a gasoline engine or a diesel engine and a vehicle equipped with an automatic transmission, the shift time by the automatic transmission can be shortened. There is a demand, but one of the necessary things for this purpose is to reduce engine inertia. In order to reduce the inertia of the engine, it is necessary to absorb the torque fluctuation of the engine without using the inertia.
In order to improve the fuel efficiency of a multi-cylinder engine, a cylinder deactivation engine has been proposed in which combustion in some cylinders is stopped according to the operating load of the engine. Since the torque fluctuation of the engine at the time of cylinder deactivation is larger than the torque fluctuation at the time of all cylinder operation in which combustion is performed in all cylinders, in order to expand the operation range in which cylinder deactivation is performed for the purpose of further improving fuel consumption performance It is necessary to be able to absorb increasing torque fluctuations of the engine.
Furthermore, engine torque fluctuations are transmitted to the passenger compartment floor via the power train from the engine mount and transmission to the drive shaft, causing noise in the passenger compartment. Therefore, in order to improve the quietness in the passenger compartment, it is necessary to improve the torque fluctuation absorption performance of the engine.

  In a hybrid vehicle equipped with an electric motor as a power source in addition to the engine, a power output device that outputs torque to the motor so as to suppress engine torque fluctuation has been proposed as means for absorbing engine torque fluctuation. (For example, refer to Patent Document 1). This conventional power output device outputs positive pulsation torque in conjunction with torque pulsation of the output shaft of the engine, and generates power by a generator using excess power output to the drive shaft, thereby The motor is controlled to suppress vibration associated with torque pulsation.

JP 2006-187168 A

  However, in the prior art as described in Patent Document 1, in order to suppress vibration associated with engine torque pulsation, torque output by a motor and power generation by a generator are generated at a high frequency in conjunction with engine torque pulsation. Since it must be controlled, the loss accompanying the input / output of electric power is large, and the energy efficiency of the entire vehicle is lowered.

  The present invention has been made to solve the above-described problems of the prior art, and is capable of effectively absorbing engine torque fluctuations while suppressing a decrease in energy efficiency. And a power control device.

In order to achieve the above object, a power control method for a hybrid vehicle according to the present invention includes an internal combustion engine, a power transmission mechanism that transmits the power of the internal combustion engine to drive wheels, and a power transmission mechanism that is connected to the internal combustion engine. A power control method for a hybrid vehicle including an electric motor capable of output, the step of estimating an average torque output from the internal combustion engine, and the step of estimating a torque fluctuation component in the torque output from the internal combustion engine A step of setting a counter torque that suppresses the torque fluctuation component, and a step of controlling the electric motor so as to output the set counter torque. The step of setting the counter torque includes the number of revolutions of the internal combustion engine. When the average torque output from the internal combustion engine is a predetermined value, the absolute value of the counter torque becomes maximum. In comprising the step of setting the counter torque, characterized in that.
In the present invention configured as described above, the absolute value of the counter torque becomes maximum when the average torque output from the internal combustion engine is a predetermined value when the rotational speed of the internal combustion engine is constant. For example, when the average torque output from the internal combustion engine is a value such that the driving force of the internal combustion engine and the running resistance of the vehicle antagonize, the vehicle speed is difficult to change. The frequency of the torque fluctuation component of the engine is difficult to change. In this case, since the frequency of the vibration accompanying the torque fluctuation of the internal combustion engine is difficult to change, resonance tends to occur in the vibration transmission path from the internal combustion engine to the passenger compartment floor, and the vibration of the passenger compartment floor tends to increase. Therefore, by setting the absolute value of the counter torque to the maximum as described above, the torque fluctuation component of the internal combustion engine can be reliably absorbed by the counter torque, and the vibration accompanying the torque fluctuation of the internal combustion engine can be effectively suppressed.

In the present invention, preferably, the step of setting the counter torque is a negative value so that the absolute value becomes maximum when the average torque output from the internal combustion engine is a predetermined value when the rotational speed of the internal combustion engine is constant. And a step of setting a counter torque based on a product of the estimated torque fluctuation component and the control gain.
In the present invention configured as described above, the negative control gain set so that the absolute value is maximized when the average torque output from the internal combustion engine is a predetermined value when the rotational speed of the internal combustion engine is constant. Since the counter torque is set based on the product of the torque fluctuation component of the internal combustion engine, the absolute value of the counter torque is maximum when the average torque output from the internal combustion engine is a predetermined value when the rotation speed of the internal combustion engine is constant. Can be. Accordingly, the torque fluctuation component of the internal combustion engine is reliably absorbed by the counter torque under the condition that resonance easily occurs in the vibration transmission path from the internal combustion engine to the vehicle compartment floor and the vibration of the vehicle compartment floor is likely to increase. The vibration accompanying the torque fluctuation can be effectively suppressed.

In the present invention, it is preferable that the step of setting the counter torque includes the step of setting the counter torque so that the absolute value of the counter torque increases as the rotational speed of the internal combustion engine increases when the average torque is constant. Including.
In the present invention configured as described above, when the average torque output from the internal combustion engine is constant, the absolute value of the counter torque increases as the rotational speed of the internal combustion engine increases. When the rotational speed of the internal combustion engine is reduced, the driving force margin is increased, so that the rotational speed of the internal combustion engine is likely to increase as the vehicle speed increases, and the frequency of the torque fluctuation component of the internal combustion engine is likely to increase. The frequency of vibration accompanying torque fluctuation is likely to change. In this case, resonance hardly occurs in the vibration transmission path from the internal combustion engine to the vehicle compartment floor, and vibration of the vehicle compartment floor does not easily increase. That is, even if the absolute value of the amplitude of the counter torque is reduced, vibration and noise on the passenger compartment floor are sufficiently suppressed. In this way, the absolute value of the counter torque is increased as the rotational speed of the internal combustion engine is increased (the absolute value of the counter torque is decreased as the rotational speed of the internal combustion engine is decreased), thereby sufficiently absorbing the torque fluctuation of the internal combustion engine. However, power consumption accompanying the generation of counter torque can be suppressed.

In the present invention, it is preferable that the step of setting the counter torque includes the step of setting the counter torque so that the absolute value of the counter torque decreases as the rotational speed of the internal combustion engine increases when the average torque is constant. Including.
In the present invention configured as described above, when the average torque output from the internal combustion engine is constant, the absolute value of the counter torque decreases as the rotational speed of the internal combustion engine increases. When the average torque output from the internal combustion engine is constant, the higher the number of revolutions of the internal combustion engine, the more easily the vibration is attenuated in the vibration transmission path from the internal combustion engine to the passenger compartment floor. . That is, even if the absolute value of the amplitude of the counter torque is reduced, vibration and noise on the passenger compartment floor are sufficiently suppressed. Therefore, by reducing the absolute value of the counter torque as the rotational speed of the internal combustion engine is increased, it is possible to suppress power consumption accompanying the generation of the counter torque while sufficiently absorbing the torque fluctuation of the internal combustion engine.

  A power control apparatus for a hybrid vehicle according to the present invention includes an internal combustion engine, a power transmission mechanism that transmits power of the internal combustion engine to drive wheels, and an electric motor that is connected to the internal combustion engine and can output power to the power transmission mechanism. A hybrid vehicle power control apparatus comprising: an average torque estimating unit that estimates an average torque output from the internal combustion engine; and a torque fluctuation component estimating unit that estimates a torque fluctuation component in the torque output from the internal combustion engine. A counter torque setting unit that sets a counter torque that suppresses the torque fluctuation component, and an electric motor control unit that controls the electric motor so as to output the set counter torque. The absolute value of the counter torque is maximum when the average torque output from the internal combustion engine is a predetermined value when the engine speed is constant. So that, to set the counter torque, characterized in that.

  In the present invention, it is preferable that the counter torque setting unit performs negative control so that the absolute value becomes maximum when the average torque output from the internal combustion engine is a predetermined value when the rotational speed of the internal combustion engine is constant. A gain is set, and a counter torque is set based on the product of the estimated torque fluctuation component and the control gain.

  In the present invention, preferably, the counter torque setting unit sets the counter torque so that the absolute value of the counter torque increases as the rotational speed of the internal combustion engine increases when the average torque is constant.

  In the present invention, it is preferable that the counter torque setting unit sets the counter torque so that the absolute value of the counter torque decreases as the rotational speed of the internal combustion engine increases when the average torque is constant.

  According to the vehicle power control method and power control apparatus of the present invention, it is possible to effectively absorb engine torque fluctuations while suppressing a decrease in energy efficiency.

1 is a schematic diagram illustrating an overall configuration of a vehicle to which a power control device according to an embodiment of the present invention is applied. 1 is a block diagram showing an electrical configuration of a vehicle to which a power control device according to an embodiment of the present invention is applied. It is a flowchart of the power control process which the power control apparatus by embodiment of this invention performs. It is the control block diagram which showed the method in which the power control apparatus by embodiment of this invention determines motor command torque. It is a diagram which shows the fluctuation component of the torque in the output shaft of an engine. It is a diagram which shows the relationship between an engine average torque and a counter torque in case an engine speed is constant. It is a diagram which shows the relationship between an engine speed and a counter torque in case an engine average torque is constant. It is a diagram which shows the relationship between the gear stage and counter torque of the automatic transmission of a vehicle in case an engine average torque and an engine speed are constant. It is a diagram which shows the relationship between the acceleration of a vehicle in case an engine average torque and an engine speed are constant, and a counter torque.

  Hereinafter, a vehicle power control method and a power control apparatus according to embodiments of the present invention will be described with reference to the accompanying drawings.

<System configuration>
First, with reference to FIG.1 and FIG.2, the structure of the vehicle to which the power control apparatus by embodiment of this invention was applied is demonstrated. FIG. 1 is a schematic diagram showing an overall configuration of a vehicle to which a power control apparatus according to an embodiment of the present invention is applied, and FIG. 2 is an electrical configuration of the vehicle to which a power control apparatus according to an embodiment of the present invention is applied. FIG.

As shown in FIG. 1, a vehicle 1 to which a power control device according to an embodiment of the present invention is applied is a hybrid vehicle including an engine 2 and a motor 4 as driving force sources. The engine 2 and the motor 4 are connected via a clutch (not shown) that connects and disconnects power transmission. An automatic transmission 6 is provided on the downstream side of the motor 4 in the power transmission path. The output of the automatic transmission 6 is transmitted to the left and right drive wheels via the differential device 8.
The vehicle 1 includes a battery 10 (secondary battery) and an inverter 12 that controls input / output of electric power between the motor 4 and the battery 10. The inverter 12 converts the DC power supplied from the battery 10 into AC power and supplies it to the motor 4, and converts the regenerative power generated by the motor 4 into DC power and supplies it to the battery 10. Charge.
Further, the vehicle 1 includes a PCM 14 (power control device) that controls the engine 2 and controls the motor 4 via the inverter 12, and a TCM 16 (Transmission Control Module) that controls the automatic transmission 6.

  As shown in FIG. 2, the vehicle 1 is provided with sensors that detect various driving states related to the vehicle 1. Specifically, these sensors are as follows. The accelerator opening sensor 18 detects an accelerator opening which is an accelerator pedal opening (corresponding to an amount by which the driver has depressed the accelerator pedal). The vehicle speed sensor 20 detects the speed (vehicle speed) of the vehicle 1. The crank angle sensor 22 detects the crank angle of the crankshaft of the engine 2. The air flow sensor 24 detects an intake air amount corresponding to the flow rate of intake air that passes through the intake passage of the engine 2. The motor angle sensor 26 detects the rotation angle of the rotor of the motor 4. Each of these various sensors outputs detection signals S118 to S126 corresponding to the detected parameters to the PCM 14.

  Further, the PCM 14 shifts the various information related to the automatic transmission 6 from the TCM 16 that controls the automatic transmission 6 of the vehicle 1 (for example, whether or not the current shift stage, the shift point at which the shift is performed has been reached, and the shift to the next shift stage. When the engine speed is input).

  The PCM 14 controls the engine 2 and the inverter 12 based on the detection signals S118 to S126 input from the various sensors described above and various information related to the automatic transmission 6 input from the TCM 16. Specifically, as shown in FIG. 2, the PCM 14 supplies a control signal S128 to the throttle valve 28 to control the opening / closing timing and throttle opening of the throttle valve 28, and sends the control signal S130 to the fuel injection valve 30. The fuel injection amount and the fuel injection timing are controlled, the control signal S132 is supplied to the spark plug 32, the ignition timing is controlled, and the control signal S134 is supplied to the intake / exhaust valve mechanism 34. The operation timing of the intake valve and the exhaust valve is controlled, and the control signal S112 is supplied to the inverter 12 to control the input / output of electric power between the motor 4 and the battery 10.

The PCM 14 stores a CPU, various programs that are interpreted and executed on the CPU (including basic control programs such as an OS and application programs that are activated on the OS to realize specific functions), programs, and various data. And a computer having an internal memory such as a ROM and a RAM.
The PCM 14 configured in this manner corresponds to the “power control device” in the present invention, and the “average torque estimation unit”, “torque fluctuation component estimation unit”, “counter torque setting unit”, and “electric motor” in the present invention. It functions as a “control unit”.

<Power control>
Next, power control executed in the embodiment of the present invention will be described with reference to FIG. FIG. 3 is a flowchart of power control processing executed by the power control apparatus according to the embodiment of the present invention.

  The power control process shown in FIG. 3 is started when the ignition of the vehicle 1 is turned on and the PCM 14 is turned on, and is repeatedly executed at a predetermined cycle. When the power control process is started, the PCM 14 acquires various types of information regarding the driving state of the vehicle 1 in step S1. Specifically, the PCM 14 determines the accelerator opening detected by the accelerator opening sensor 18, the vehicle speed detected by the vehicle speed sensor 20, the crank angle detected by the crank angle sensor 22, the intake air amount detected by the airflow sensor 24, and the motor angle. The rotation angle of the rotor of the motor 4 detected by the sensor 26, the current gear position of the automatic transmission 6 input from the TCM 16, and the like are acquired.

  Next, in step S2, the PCM 14 sets a target acceleration based on the driving state of the vehicle 1 acquired in step S1. Specifically, the PCM 14 has a plurality of acceleration characteristic maps (created in advance and stored in a memory or the like) that define the relationship between the accelerator opening and the acceleration for various vehicle speeds and various shift speeds. An acceleration characteristic map corresponding to the current vehicle speed and gear position is selected. The acceleration corresponding to the accelerator opening detected by the accelerator opening sensor 18 is set as a target acceleration with reference to the selected acceleration characteristic map.

Next, in step S3, the PCM 14 sets a target engine torque and a target motor torque for realizing the target acceleration set in step S2, based on the driving state acquired in step S1.
The PCM 14 sets a target value for the total torque of the engine 2 and the motor 4 based on the current vehicle speed, shift speed, road surface gradient, road surface μ, and the like. Further, referring to a fuel consumption rate characteristic map (created in advance and stored in a memory or the like) that defines the relationship between the engine torque and the engine speed at which the fuel consumption rate (g / kWh) is minimized, step S1 The engine torque corresponding to the current engine speed calculated based on the crank angle acquired in is set as the target engine torque. A value obtained by subtracting the target engine torque from the target value of the total torque is set as the target motor torque.
For example, when the target value of the total torque is larger than the target engine torque, a positive target motor torque is set. That is, while the engine 2 is operated in a region where the fuel consumption rate is small, the motor 4 compensates for the insufficient torque, so that the torque necessary for realizing the target acceleration is output.
On the other hand, when the target value of the total torque is smaller than the target engine torque, a negative target motor torque is set. That is, while operating the engine 2 in a region where the fuel consumption rate is small, the surplus torque is used for power generation by the motor 4 to charge the battery 10, thereby realizing the target acceleration while charging the battery 10 efficiently. Therefore, it is possible to output a necessary torque.

Next, in step S4, the PCM 14 performs each actuator (for example, spark plug 32, throttle valve 28, etc.) of the engine 2 for realizing the target engine torque set in step S3 based on the operation state acquired in step S1. The control value of the intake / exhaust valve mechanism 34) is determined.
Specifically, the PCM 14 calculates a target indicated torque by adding a loss loss due to friction loss or pumping loss to the target engine torque, and shows the relationship between the ignition timing and the indicated torque for various charging efficiencies and various engine speeds. A range that corresponds to the current engine speed and does not cause knocking from a specified ignition advance map (previously created and stored in a memory or the like) (a knock limit set in advance in each ignition advance map) The ignition advance map is selected so that the target indicated torque is obtained when the ignition timing is as close as possible to the MBT in the retarded angle range with respect to the ignition timing, and the target indicated torque is referenced with reference to the selected ignition advance map. Is set as the ignition timing.
Further, the PCM 14 obtains a heat amount (required heat amount) necessary for outputting the target indicated torque, and sets the charging efficiency necessary for generating the required heat amount as the target charging efficiency. Then, the PCM 14 considers the amount of air detected by the air flow sensor 24 so that air corresponding to the set target charging efficiency is introduced into the engine 2, and the opening degree of the throttle valve 28 and the intake / exhaust valve mechanism 34. The opening and closing timing of the intake valve via the is set.

  Next, in step S5, the PCM 14 outputs to the motor 4 based on the operation state acquired in step S1, the target motor torque set in step S3, and the control amount of each actuator of the engine 2 set in step S4. Torque to be performed (motor command torque), specifically, an input / output control value of power between the motor 4 and the battery 10 by the inverter 12 is determined.

  Here, with reference to FIG.4 and FIG.5, the determination method of the motor command torque by PCM14 is demonstrated. FIG. 4 is a control block diagram illustrating a method for determining the motor command torque by the power control apparatus according to the embodiment of the present invention. FIG. 5 is a diagram showing a torque fluctuation component on the output shaft of the engine 2. Chart (a) shows a torque fluctuation on the output shaft of the engine 2. Chart (b) shows a torque fluctuation component. A diagram showing components due to pressure change of combustion gas in the cylinder, chart (c) is a diagram showing components due to inertia of reciprocating mass inside the engine 2 among torque fluctuation components, and chart (d) is a diagram (d). FIG. 5 is a diagram showing a torque fluctuation component obtained by synthesizing a component caused by pressure change of combustion gas in a cylinder and a component caused by inertia of reciprocating mass inside the engine 2. The horizontal axis in each chart of FIG. 5 indicates the crank angle (deg), and the vertical axis indicates the torque (Nm).

  As shown in FIG. 4, the PCM 14 includes an engine average torque estimation unit 36 that estimates an average torque (engine average torque) generated by the engine 2 in one cycle, and a torque fluctuation component (torque fluctuation component) on the output shaft of the engine 2. ) And a motor command torque determining unit 40 for determining a torque (motor command torque) to be output to the motor 4.

  The engine average torque estimating unit 36 receives the intake air amount and the crank angle acquired in step S1 as inputs. The engine average torque estimation unit 36 estimates the charging efficiency based on the intake air amount acquired in step S1, and obtains the indicated torque corresponding to the amount of heat generated when air is introduced into the engine 2 with the estimated charging efficiency. The average engine torque is estimated by subtracting the torque loss due to friction loss and pumping loss. Moreover, the engine average torque estimation part 36 calculates an engine speed based on the crank angle acquired in step S1.

  The torque fluctuation component estimator 38 is based on the engine average torque estimated by the engine average torque estimator 36, the engine speed calculated by the engine average torque estimator 36, and the crank angle acquired in step S1. Estimate torque fluctuation components.

  As shown in the chart (a) of FIG. 5, the torque at the output shaft of the engine 2 (shown by a solid line in FIG. 5) is a torque (a finger pressure torque, a broken line in FIG. 5) resulting from the pressure change of the combustion gas in the cylinder. And torque (inertia torque, indicated by a one-dot chain line in FIG. 5) due to the inertia of the reciprocating mass (piston, connecting rod, etc.) inside the engine 2 can be separated.

  Of these, fluctuations in the acupressure torque are expressed as a sine vibration (so-called secondary vibration) with a crank angle of 180 deg as one cycle and a higher-order vibration, but vibration transmission to the passenger compartment floor, etc. The second problem is the secondary vibration. Therefore, as shown in the chart (b), when the secondary vibration component in the fluctuation of the acupressure torque based on the engine average torque is extracted, the torque fluctuation component (acupressure pressure fluctuation component) resulting from the fluctuation of the acupressure torque is used as a crank. A sinusoidal vibration having an angle of 180 deg as one cycle is obtained. The amplitude of this finger pressure torque fluctuation component can be expressed as a function of engine average torque, and increases in proportion to the increase in engine average torque.

  Further, as shown in the chart (c), the torque fluctuation component (inertia torque fluctuation component) resulting from the fluctuation of the inertia torque is expressed as a sinusoidal vibration having an opposite phase to the acupressure torque fluctuation component shown in the chart (b). . The amplitude of the inertia torque fluctuation component can be expressed as a function of the engine speed, and increases as the engine speed increases.

As shown in the chart (d), the torque fluctuation component of the engine 2 is a crank angle of 180 deg, which is a combination of the acupressure torque fluctuation component shown in the chart (b) and the inertia torque fluctuation component shown in the chart (c). It is expressed as sinusoidal vibration with one period. As described above, the amplitude of the acupressure torque fluctuation component is expressed as a function of the engine average torque, and the amplitude of the inertia torque fluctuation component is expressed as a function of the engine speed. The amplitude can be expressed as a function A _tr (Te, Ne) of the engine average torque Te and the engine speed Ne. Therefore, the torque fluctuation component of the engine 2 is expressed as a sine function A _tr (Te, Ne) Sin (CA) having a crank angle CA as a variable and an amplitude of A _tr (Te, Ne).

The torque fluctuation component estimation unit 38 calculates the crank angle CA acquired in step S1, the engine average torque Te estimated by the engine average torque estimation unit 36, and the engine speed Ne calculated by the engine average torque estimation unit 36. The torque fluctuation component is estimated by substituting it into the sine function A _tr (Te, Ne) × Sin (CA) shown in the chart (d).

As shown in FIG. 4, in addition to the motor angle acquired in step S1 and the target motor torque set in step S3, the motor command torque determination unit 40 includes the torque fluctuation estimated by the torque fluctuation component estimation unit 38. A value obtained by multiplying the component by a predetermined control gain (“K” in FIG. 4) is input as the counter torque. The control gain K is a gain (counter torque control gain) set so that the motor 4 outputs a counter torque that can effectively absorb the torque fluctuation of the engine 2 while suppressing a decrease in energy efficiency. Thus, a range of −1 ≦ K ≦ 0 is set according to the operating state acquired in step S1 and the target engine torque set in step S3. That is, as the counter torque, a value opposite in phase to the torque fluctuation component of the engine 2 and a displacement equal to or smaller than the displacement of the torque fluctuation component is input to the motor command torque determination unit 40. Details of the setting of the counter torque control gain will be described later.
The motor command torque determination unit 40 determines the motor command torque based on the motor angle acquired in step S1, the target motor torque set in step S3, and the counter torque. Specifically, the motor command torque determination unit 40 uses the total value of the target motor torque and the counter torque set in step S3 as the motor command torque at the motor angle corresponding to the crank angle CA acquired in step S1. Determine and output to the inverter 12.

  Returning to FIG. 3, after determining the motor command torque in step S5, the PCM 14 proceeds to step S6 and controls the throttle valve 28 and the intake / exhaust valve mechanism 34 based on the engine actuator control value determined in step S4. The fuel injection valve 30 is controlled based on the target equivalence ratio determined according to the operating state of the engine 2 and the actual air amount estimated based on the detection signal S124 of the airflow sensor 24 and the like. Further, the PCM 14 controls input / output of electric power between the motor 4 and the battery 10 by the inverter 12 so that the motor 4 outputs the motor command torque determined in step S5. After step S6, the PCM 14 ends one cycle of the power control process.

<Counter torque control gain setting>
Next, the setting of the counter torque control gain by the PCM 14 will be described with reference to FIGS.
FIG. 6 is a diagram showing the relationship between the engine average torque and the counter torque when the engine speed is constant, and the chart (a) shows the relationship between the engine average torque and the amplitude of the torque fluctuation component of the engine 2. The chart (b) shows the relationship between the engine average torque and the absolute value of the control gain, and the chart (c) shows the relationship between the engine average torque and the absolute value of the counter torque amplitude.

As described above, the torque fluctuation component on the output shaft of the engine 2 is obtained by combining the acupressure torque fluctuation component and the inertia torque fluctuation component. The amplitude of the acupressure torque variation component can be expressed as a function of engine average torque, and increases in proportion to the increase in engine average torque. The amplitude of the inertia torque fluctuation component can be expressed as a function of the engine speed, and increases as the engine speed increases. Therefore, as shown in the chart (a) of FIG. 6, when the engine speed is constant, the amplitude of the torque fluctuation component of the engine 2 increases in proportion to the increase in the engine average torque.
In this case, as shown in the chart (b), in the range where the engine average torque is less than the predetermined value Te1, the absolute value of the control gain is set to a constant value (specifically 1), and the engine average torque is set to the predetermined value Te1. In the above range, the absolute value of the control gain is set to be smaller as the engine average torque is larger.
Therefore, as shown in the chart (c), in the range where the engine average torque is equal to or less than the predetermined value Te1, the absolute value of the amplitude of the counter torque increases as the engine average torque increases. Further, in the range where the engine average torque is larger than the predetermined value Te1, as the absolute value of the control gain decreases as the engine average torque increases, the rate of increase in the absolute value of the counter torque amplitude becomes gradual. When is a predetermined value Te2, the absolute value of the amplitude of the counter torque becomes a maximum. Further, in the range where the engine average torque is larger than Te2, the absolute value of the amplitude of the counter torque decreases as the engine average torque increases.

That is, the larger the engine average torque, the larger the amplitude of the torque fluctuation component, but in the range where the engine average torque is equal to or less than the predetermined value Te1, the larger the engine average torque, the larger the absolute value of the counter torque amplitude. Thus, the torque fluctuation component of the engine 2 can be reliably absorbed, and the vibration accompanying the torque fluctuation of the engine 2 can be suppressed.
Further, when the engine average torque is in the vicinity of the predetermined value Te2, the driving speed of the engine 2 and the running resistance of the vehicle 1 are antagonized so that the vehicle speed is difficult to change. The frequency of is difficult to change. In this case, since the frequency of vibration associated with torque fluctuations of the engine 2 is difficult to change, resonance is likely to occur in the vibration transmission path from the engine 2 to the vehicle compartment floor, and vibration of the vehicle compartment floor tends to increase. Therefore, by setting the absolute value of the amplitude of the counter torque to a maximum, the torque fluctuation component of the engine 2 can be reliably absorbed by the counter torque, and the vibration accompanying the torque fluctuation of the engine 2 can be suppressed.
Further, in the range where the engine average torque is larger than the predetermined value Te2, the larger the engine average torque, the greater the driving force margin by the engine 2 and the higher the vehicle speed, so the engine speed increases as the vehicle speed increases. As a result, the frequency of the torque fluctuation component of the engine 2 tends to increase. In this case, since the frequency of vibration associated with torque fluctuations of the engine 2 is likely to change, resonance is unlikely to occur in the vibration transmission path from the engine 2 to the passenger compartment floor, and vibration of the passenger compartment floor is unlikely to increase. That is, even if the absolute value of the amplitude of the counter torque is reduced, vibration and noise on the passenger compartment floor are sufficiently suppressed. Thus, by reducing the absolute value of the amplitude of the counter torque as the engine average torque increases, it is possible to suppress power consumption associated with the generation of the counter torque while sufficiently absorbing the torque fluctuation of the engine 2.

  FIG. 7 is a diagram showing the relationship between the engine speed and the counter torque when the engine average torque is constant. Chart (a) shows the relationship between the engine speed and the amplitude of the torque fluctuation component of the engine 2. The chart (b) shows the relationship between the engine speed and the absolute value of the control gain, and the chart (c) shows the relationship between the engine speed and the absolute value of the counter torque amplitude.

As described above, the torque fluctuation component on the output shaft of the engine 2 is obtained by combining the acupressure torque fluctuation component and the inertial torque fluctuation component having a phase opposite to that of the acupressure torque fluctuation component. The amplitude of the acupressure torque variation component can be expressed as a function of engine average torque, and increases in proportion to the increase in engine average torque. The amplitude of the inertia torque fluctuation component can be expressed as a function of the engine speed, and increases as the engine speed increases. Therefore, as shown in the chart (a) of FIG. 7, when the engine average torque is constant, the engine speed is within a range of less than the engine speed Ne1 where the amplitude of the finger pressure torque fluctuation component and the amplitude of the inertia torque fluctuation component coincide. The higher the number, the smaller the amplitude of the torque fluctuation component of the engine 2, and in the range of the engine speed Ne1 or higher where the amplitude of the acupressure torque fluctuation component and the amplitude of the inertia torque fluctuation component coincide, the higher the engine speed, The amplitude of the torque fluctuation component is large.
In this case, as shown in the chart (b), in the range where the engine speed is less than a predetermined value Ne2 close to the resonance frequency in the vibration transmission path from the engine 2 to the vehicle compartment floor, the higher the engine speed, the higher the control gain. The absolute value of the control gain is set so as to increase as the engine speed increases in the range where the engine speed is equal to or greater than the predetermined value Ne2.
Therefore, as shown in the chart (c), in the range where the engine speed is less than the predetermined value Ne2, the absolute value of the amplitude of the counter torque increases as the engine speed increases. Further, the absolute value of the amplitude of the counter torque becomes maximum when the engine speed is in the vicinity of the predetermined value Ne2. Further, in the range where the engine speed is higher than Ne2, the absolute value of the amplitude of the counter torque decreases as the engine speed increases.

That is, in the range where the engine speed is less than the predetermined value Ne2, the driving force margin of the engine 2 is large and the vehicle speed is likely to increase. Therefore, the torque fluctuation component of the engine 2 increases as the engine speed increases as the vehicle speed increases. The frequency tends to increase. In this case, since the frequency of vibration associated with torque fluctuations of the engine 2 is likely to change, resonance is unlikely to occur in the vibration transmission path from the engine 2 to the passenger compartment floor, and vibration of the passenger compartment floor is unlikely to increase. That is, even if the absolute value of the amplitude of the counter torque is reduced, vibration and noise on the passenger compartment floor are sufficiently suppressed. Therefore, by reducing the absolute value of the amplitude of the counter torque as the engine speed is lower, it is possible to suppress power consumption associated with the generation of the counter torque while sufficiently absorbing the torque fluctuation of the engine 2.
Further, when the engine speed is in the vicinity of the predetermined value Ne2, the engine speed is close to the resonance frequency in the vibration transmission path from the engine 2 to the passenger compartment floor, so that resonance occurs in the vibration transmission path from the engine 2 to the passenger compartment floor. It tends to occur and the vibration of the passenger compartment floor tends to increase. Therefore, by setting the absolute value of the amplitude of the counter torque to a maximum, the torque fluctuation component of the engine 2 can be reliably absorbed by the counter torque, and the vibration accompanying the torque fluctuation of the engine 2 can be suppressed.
Further, in the range where the engine speed is higher than the predetermined value Ne2, the vibration is more likely to be attenuated in the vibration transmission path from the engine 2 to the passenger compartment floor as the engine rotational speed is higher. . That is, even if the absolute value of the amplitude of the counter torque is reduced, vibration and noise on the passenger compartment floor are sufficiently suppressed. Therefore, the higher the engine speed, the smaller the absolute value of the amplitude of the counter torque, so that the power consumption accompanying the generation of the counter torque can be suppressed while sufficiently absorbing the torque fluctuation of the engine 2.

  FIG. 8 is a diagram showing the relationship between the gear position of the automatic transmission 6 of the vehicle 1 and the counter torque when the engine average torque and the engine speed are constant, and the chart (a) shows the relationship between the gear position and the engine 2. The figure which shows the relationship between the amplitude of a torque fluctuation component, Chart (b) is a figure which shows the relationship between a gear position and the absolute value of a control gain, Chart (c) is the relationship between the gear position and the absolute value of the amplitude of a counter torque. FIG.

As described above, the torque fluctuation component on the output shaft of the engine 2 is obtained by combining the acupressure torque fluctuation component and the inertial torque fluctuation component having a phase opposite to that of the acupressure torque fluctuation component. Therefore, as shown in the chart (a) of FIG. 8, when the engine average torque and the engine speed are constant, the amplitude of the torque fluctuation component of the engine 2 is constant regardless of the shift level.
In this case, as shown in the chart (b), the absolute value of the control gain is set to be larger as the gear position of the vehicle 1 is higher (the reduction ratio is smaller).
Therefore, as shown in the chart (c), the absolute value of the counter torque amplitude increases as the speed of the vehicle 1 increases, and the absolute value of the counter torque decreases as the speed of the vehicle 1 decreases. .

  That is, the lower the gear position of the vehicle 1, the greater the driving force margin of the engine 2 and the higher the vehicle speed. Therefore, the frequency of the torque fluctuation component of the engine 2 increases as the engine speed increases as the vehicle speed increases. Easy to rise. In this case, since the frequency of vibration associated with torque fluctuations of the engine 2 is likely to change, resonance is unlikely to occur in the vibration transmission path from the engine 2 to the passenger compartment floor, and vibration of the passenger compartment floor is unlikely to increase. That is, even if the absolute value of the amplitude of the counter torque is reduced, vibration and noise on the passenger compartment floor are sufficiently suppressed. Therefore, by reducing the absolute value of the amplitude of the counter torque as the gear position of the vehicle 1 is lower, it is possible to suppress power consumption associated with the generation of the counter torque while sufficiently absorbing the torque fluctuation of the engine 2.

  FIG. 9 is a diagram showing the relationship between the acceleration of the vehicle 1 and the counter torque when the engine average torque and the engine speed are constant, and the chart (a) shows the acceleration and the amplitude of the torque fluctuation component of the engine 2. FIG. 5 is a diagram showing the relationship, chart (b) is a diagram showing the relationship between the acceleration and the absolute value of the control gain, and chart (c) is a diagram showing the relationship between the acceleration and the absolute value of the amplitude of the counter torque.

As described above, the torque fluctuation component on the output shaft of the engine 2 is obtained by combining the acupressure torque fluctuation component and the inertial torque fluctuation component having a phase opposite to that of the acupressure torque fluctuation component. Therefore, as shown in the chart (a) of FIG. 9, when the engine average torque and the engine speed are constant, the amplitude of the torque fluctuation component of the engine 2 is constant regardless of the magnitude of the acceleration.
In this case, as shown in the chart (b), the absolute value of the control gain is set to be larger as the acceleration of the vehicle 1 is closer to zero.
Therefore, as shown in the chart (c), the closer the acceleration of the vehicle 1 is to 0, the greater the absolute value of the amplitude of the counter torque.

  That is, the closer the acceleration of the vehicle 1 is to 0, that is, the smaller the change in the vehicle speed, the smaller the change in the engine speed and the less the frequency of the torque fluctuation component of the engine 2 changes. In this case, since the frequency of vibration associated with torque fluctuations of the engine 2 is difficult to change, resonance is likely to occur in the vibration transmission path from the engine 2 to the vehicle compartment floor, and vibration of the vehicle compartment floor tends to increase. In addition, when the frequency of the vibration of the passenger compartment floor is constant, it is easy for the passenger to feel the vibration. Therefore, by increasing the absolute value of the counter torque amplitude as the acceleration of the vehicle 1 is closer to 0, the torque fluctuation component of the engine 2 is reliably absorbed by the counter torque, and vibrations associated with the torque fluctuation of the engine 2 are suppressed. can do.

1 Vehicle 2 Engine 4 Motor 6 Automatic Transmission 8 Differential Device 10 Battery 12 Inverter 14 PCM
16 TCM
18 Accelerator opening sensor 20 Vehicle speed sensor 22 Crank angle sensor 24 Air flow sensor 26 Motor angle sensor 28 Throttle valve 30 Fuel injection valve 32 Spark plug 34 Intake / exhaust valve mechanism 36 Engine average torque estimation unit 38 Torque fluctuation component estimation unit 40 Motor command torque Decision part

Claims (8)

A power control method for a hybrid vehicle, comprising: an internal combustion engine; a power transmission mechanism that transmits power of the internal combustion engine to drive wheels; and an electric motor that is coupled to the internal combustion engine and can output power to the power transmission mechanism. And
Estimating an average torque output by the internal combustion engine;
Estimating a torque fluctuation component in torque output by the internal combustion engine;
Setting a counter torque that suppresses the estimated torque fluctuation component;
Controlling the electric motor to output the set counter torque, and
The step of setting the counter torque includes the step of setting the counter torque so that the absolute value of the counter torque becomes maximum when the average torque output from the internal combustion engine is a predetermined value when the rotational speed of the internal combustion engine is constant. Including the step of setting torque,
A power control method for a hybrid vehicle. The step of setting the counter torque includes:
Setting a negative control gain so that the absolute value is maximized when the average torque output by the internal combustion engine is the predetermined value when the rotational speed of the internal combustion engine is constant;
The hybrid vehicle power control method according to claim 1, further comprising: setting the counter torque based on a product of the estimated torque fluctuation component and the control gain.   The step of setting the counter torque includes the step of setting the counter torque so that the absolute value of the counter torque increases as the rotational speed of the internal combustion engine increases when the average torque is constant. 3. A power control method for a hybrid vehicle according to 1 or 2.   The step of setting the counter torque includes the step of setting the counter torque so that the absolute value of the counter torque decreases as the rotational speed of the internal combustion engine increases when the average torque is constant. 3. A power control method for a hybrid vehicle according to 1 or 2. A power control apparatus for a hybrid vehicle, comprising: an internal combustion engine; a power transmission mechanism that transmits power of the internal combustion engine to drive wheels; and an electric motor that is connected to the internal combustion engine and can output power to the power transmission mechanism. And
An average torque estimator for estimating an average torque output from the internal combustion engine;
A torque fluctuation component estimator for estimating a torque fluctuation component in the torque output from the internal combustion engine;
A counter torque setting unit for setting a counter torque for suppressing the estimated torque fluctuation component;
An electric motor control unit for controlling the electric motor to output the set counter torque,
The counter torque setting unit sets the counter torque so that the absolute value of the counter torque becomes a maximum when the average torque output from the internal combustion engine is a predetermined value when the rotational speed of the internal combustion engine is constant. Set,
A power control apparatus for a hybrid vehicle. The counter torque setting unit
A negative control gain is set so that the absolute value is maximized when the average torque output by the internal combustion engine is the predetermined value when the rotational speed of the internal combustion engine is constant;
6. The power control apparatus for a hybrid vehicle according to claim 5, wherein the counter torque is set based on a product of the estimated torque fluctuation component and the control gain.   7. The counter torque setting unit according to claim 5, wherein the counter torque setting unit sets the counter torque so that the absolute value of the counter torque increases as the rotational speed of the internal combustion engine increases when the average torque is constant. Power control device for hybrid vehicle.   7. The counter torque setting unit according to claim 5, wherein the counter torque setting unit sets the counter torque so that the absolute value of the counter torque decreases as the rotational speed of the internal combustion engine increases when the average torque is constant. Power control device for hybrid vehicle.

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