JP6156619B2 - Hybrid vehicle operation control device - Google Patents

Description

  The present invention relates to a generator and engine operation control technology in a hybrid vehicle.

In a hybrid vehicle that has been developed in recent years, an engine, a generator that is driven by the engine to generate electric power, a driving battery that is supplied with electric power and can be charged, and an electric power that is supplied from the driving battery or the electric generator There is known a vehicle including a drive motor that drives drive wheels.
In the hybrid vehicle as described above, the electric power generated by the generator is supplied to the drive battery and the drive motor. Further, when the vehicle is decelerated, regenerative power generation is performed by the drive motor, and the generated power is supplied to the drive battery so that charging is possible.

  Furthermore, in Patent Document 1, in a hybrid vehicle, when the vehicle is decelerated, for example, when the charge rate of the drive battery is high and all the electric power regenerated by the drive motor cannot be charged, surplus power is supplied to the generator. A technology that consumes surplus power by driving with an engine has been proposed.

Japanese Patent No. 4501913

By the way, in the hybrid vehicle having the generator driven by the engine as described above, there is a technique for controlling the rotation speed of the engine by controlling the output (generated power) in the generator and changing the engine load. Has been developed.
In this way, when the engine speed is controlled by the output control of the generator, control with better responsiveness than the engine speed control by the fuel injection amount control or the like becomes possible.

However, when the driving battery that receives the power generated by the generator is in a high charge rate state or a low temperature state, the amount of power received is limited. Therefore, there has been a problem that the output of the generator has to be reduced, the engine speed increases, and it becomes difficult to control the engine speed to the target value.
The present invention has been made to solve the above-described problems. The object of the present invention is to appropriately control the driving torque of the generator and the engine regardless of the state of the driving battery so as to rotate the engine. An object of the present invention is to provide an operation control device for a hybrid vehicle capable of accurately controlling the speed.

In order to achieve the above object, an operation control device for a hybrid vehicle according to claim 1 is an engine mounted on a vehicle, a generator driven by the engine to generate electric power, and can be charged by being supplied with electric power from the generator. When the generator input shaft and the engine output shaft are in a directly connected state, the engine drive required torque is changed to the required power generation torque according to the generator required output. And setting the generator drive torque to a value obtained by correcting the required power generation torque with the first torque correction amount set according to the speed difference between the actual engine speed and the target engine speed. An operation control device for a hybrid vehicle comprising a control means for controlling the rotational speed, wherein the control means generates power when the power acceptance state of the drive battery has dropped below a predetermined value. Sets the driving torque of the machine to the first second value obtained by correcting the required power generation torque by the torque correction amount based on the limit value of the torque correction amount, the drive request torque of the engine from the first torque correction amount 2 The engine rotational speed control is changed so that the required power generation torque is set to a value corrected by a third torque correction amount that is a value obtained by subtracting the torque correction amount.

Also, the hybrid vehicle operation control apparatus according to claim 2, in claim 1, the power receiving state of the drive battery is characterized in that it is determined based on the temperature of the drive battery.

According to a third aspect of the present invention, there is provided the hybrid vehicle operation control device according to the first aspect, wherein the power acceptance state of the driving battery is determined based on a charging rate of the driving battery.
According to a fourth aspect of the present invention, there is provided the hybrid vehicle operation control device according to any one of the first to third aspects, wherein the maximum rate of change of the third torque correction amount is greater than the maximum rate of change of the second torque correction amount. It is set so that it may become small.

According to the hybrid vehicle operation control apparatus of claim 1, when the input shaft of the generator and the output shaft of the engine are in a directly connected state and the power acceptance state of the driving battery is equal to or greater than a predetermined value, the engine drive request torque Is set to the required power generation torque of the generator, and the required power generation torque is corrected by the first torque correction amount that is set according to the speed difference between the actual engine speed and the target engine speed. By setting the value, the engine speed can be controlled with high accuracy. Then, when the power acceptance state of the driving battery has decreased below a predetermined value, the required driving torque of the generator is set to the second torque correction amount based on the limit value of the first torque correction amount. In addition to setting the corrected value, the engine drive request torque is set to a value obtained by correcting the required power generation torque with a third torque correction amount that is a value obtained by subtracting the second torque correction amount from the first torque correction amount. By changing the engine speed control as described above, even if the power receiving state of the driving battery is reduced and the generator driving torque is limited, it is compensated by correcting the engine driving request torque, and the engine rotation The speed can be controlled. Therefore, it is possible to accurately control the rotational speed of the engine regardless of the power acceptance state of the driving battery.

In particular, the third torque correction amount, since it is set to a value obtained by subtracting the second torque correction amount from a first torque correction amount, the power receiving state of the driving battery is set when less than a predetermined value A value obtained by adding the second torque correction amount and the third torque correction amount to the first torque correction amount set when the power acceptance state of the driving battery is equal to or greater than a predetermined value, The driving torque of the generator, which is limited as the power receiving state of the driving battery decreases, can be completely compensated by correcting the driving torque of the engine, and the engine speed is controlled even when the power receiving state decreases. be able to.
According to the hybrid vehicle operation control device of the second aspect , since the power acceptance state of the drive battery is determined based on the temperature of the drive battery, the power of the drive battery accompanying a decrease in the temperature of the drive battery. Even if the driving torque of the generator is limited due to the decrease in the acceptance state, the engine driving torque can be corrected and the engine speed can be controlled with high accuracy.

According to the hybrid vehicle operation control apparatus of the third aspect , since the power acceptance state of the drive battery is determined based on the charge rate of the drive battery, the charge rate of the drive battery is increased and fully charged. Even when the power acceptance state of the driving battery is reduced as the speed approaches, and the driving torque of the generator is limited, the engine driving torque can be corrected and the rotational speed of the engine can be accurately controlled.

According to the hybrid vehicle operation control apparatus of the fourth aspect , the maximum change rate of the third torque correction amount is set to be smaller than the maximum change rate of the second torque correction amount. With respect to an engine having a response of a change in driving torque lower than that of the engine, the driving torque can be gradually changed to suppress engine hunting.

1 is a schematic configuration diagram of a plug-in hybrid vehicle according to an embodiment of the present invention. It is a flowchart which shows the setting point of the request | required engine torque and generator torque in the hybrid control unit of this embodiment. It is a time chart which shows an example of transition of demand engine torque, generator torque, and real engine speed at the time of normal at the time of decreasing target engine speed of an engine. It is a time chart which shows an example of transition of demand engine torque at the time of battery acceptance shortage at the time of decreasing target engine speed of an engine, generator torque, and real engine speed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a plug-in hybrid vehicle (hereinafter referred to as a vehicle 1) according to an embodiment of the present invention.
The vehicle 1 according to this embodiment is capable of driving by driving the front wheels 3 by the output of the engine 2, and includes an electric front motor 4 that drives the front wheels 3 and an electric rear motor 6 that drives the rear wheels 5. It is a wheel drive vehicle.

The engine 2 can drive the drive shaft 8 of the front wheel 3 via the speed reducer 7 and can drive the generator 9 to generate power. In the present embodiment, the output shaft of the engine 2 and the input shaft of the generator 9 are directly connected. Therefore, the rotational speed of the output shaft of the engine 2 and the rotational speed of the input shaft of the generator 9 coincide.
The front motor 4 is driven by being supplied with high-voltage power from the drive battery 11 and the generator 9 mounted on the vehicle 1 via the front inverter 10, and the drive shaft 8 of the front wheel 3 via the speed reducer 7. Drive. The speed reducer 7 incorporates a clutch 7 a capable of switching connection / disconnection of power between the output shaft of the engine 2 and the drive shaft 8 of the front wheel 3.

The rear motor 6 is driven by being supplied with high voltage power from the drive battery 11 and the generator 9 via the rear inverter 12, and drives the drive shaft 14 of the rear wheel 5 via the speed reducer 13.
The electric power generated by the generator 9 can charge the driving battery 11 via the front inverter 10 and can supply electric power to the front motor 4 and the rear motor 6.

  The drive battery 11 is composed of a secondary battery such as a lithium ion battery, and has a battery module (not shown) configured by collecting a plurality of battery cells. Further, the battery module charge rate (State Of Charge, Hereinafter, a battery monitoring unit 11a for monitoring the SOC), temperature, and the like is provided. Further, the battery monitoring unit 11a has a function of calculating the acceptable power Wb to the driving battery 11 from the charging rate SOC and temperature of the battery module. Acceptable power Wb is the maximum power that can be input to drive battery 11 and has a tendency to decrease as the charging rate SOC increases and to decrease as temperature decreases. ing. In the battery monitoring unit 11a, a map of the acceptable power Wb with respect to the charging rate SOC and temperature is stored in advance, and the acceptable power Wb (power acceptance state) of the drive battery 11 is obtained using this map.

  The front inverter 10 includes a front motor control unit 10a and a generator control unit 10b (control means). The front motor control unit 10a controls the output of the front motor 4 based on a control signal from the hybrid control unit 20 (control means). The generator control unit 10b has a function of controlling the output (generated power) of the generator 9 based on a control signal (a generator torque Pg described later) from the hybrid control unit 20.

The rear inverter 12 has a rear motor control unit 12a. The rear motor control unit 12 a has a function of controlling the output of the rear motor 6 based on a control signal from the hybrid control unit 20.
The vehicle 1 is also provided with a charger 21 that charges the drive battery 11 with an external power source.

The hybrid control unit 20 is a control device for performing comprehensive control of the vehicle 1, and includes an input / output device, a storage device (ROM, RAM, nonvolatile RAM, etc.), a central processing unit (CPU), a timer, and the like. It is comprised including.
On the input side of the hybrid control unit 20 are a battery monitoring unit 11a for the drive battery 11, a front motor control unit 10a and a generator control unit 10b for the front inverter 10, a rear motor control unit 12a for the rear inverter 12, and a drive for the engine 2. An engine control unit 22 (control means) that performs control and an accelerator opening sensor 40 that detects an accelerator operation amount are connected, and detection and operation information from these devices is input.

On the other hand, on the output side of the hybrid control unit 20, a front motor control unit 10a and a generator control unit 10b of the front inverter 10, a rear motor control unit 12a of the rear inverter 12, a speed reducer 7 (clutch 7a), an engine control unit 22 are provided. Is connected.
Then, the hybrid control unit 20 calculates a vehicle request output required for driving the vehicle based on the various detection amounts and various operation information of the accelerator opening sensor 40 and the like, and the engine control unit 22, front motor Control signals are transmitted to the control unit 10a, the generator control unit 10b, the rear motor control unit 12a, and the speed reducer 7 to switch the driving mode ((EV mode, electric vehicle mode), series mode, parallel mode), the engine 4 and The outputs of the front motor 9 and the rear motor 11 and the output of the generator 9 are controlled.

In the EV mode, the engine 2 is stopped, and the front motor 4 and the rear motor 6 are driven by the electric power supplied from the driving battery 11 to run.
In the series mode, the clutch 7 a of the speed reducer 7 is disconnected and the generator 9 is operated by the engine 2. Then, the front motor 4 and the rear motor 6 are driven to run by the power generated by the generator 9 and the power supplied from the driving battery 11. In the series mode, the rotational speed of the engine 2 is set to the target rotational speed Vt, and the electric power generated by the surplus output is supplied to the driving battery 11 to charge the driving battery 11.

In the parallel mode, the clutch 7 a of the speed reducer 7 is connected, and the power is mechanically transmitted from the engine 2 via the speed reducer 7 to drive the front wheels 3. Further, the front motor 4 and the rear motor 6 are driven to run by the electric power generated by operating the generator 9 by the engine 2 and the electric power supplied from the driving battery 11.
The hybrid control unit 20 sets the traveling mode to the parallel mode in an efficient region of the engine 2 such as a high speed region. Further, in the region excluding the parallel mode, that is, the middle / low speed region, the mode is switched between the EV mode and the series mode based on the charging rate SOC of the driving battery 11.

Further, when the charging rate SOC of the drive battery 11 falls below the allowable range, the hybrid control unit 20 forcibly drives the engine 2 to generate electric power and charge the drive battery 11.
In the present embodiment, the driving torque of the generator 9 (generator torque Pg) and the required driving torque of the engine 2 (required engine torque Pe) are controlled in the travel mode in which the generator 9 is driven by the engine 2 as in the series mode. Thus, it has a function of setting the actual rotational speed V of the engine 2 to the target rotational speed Vt.

FIG. 2 is a flowchart showing how to set the required engine torque Pe and the generator torque Pg in the hybrid control unit 20.
This control is repeatedly executed every predetermined time in the series mode.
First, in step S10, it is determined whether or not the acceptable power Wb input from the battery monitoring unit 11a is equal to or greater than a predetermined value Wb1. If the acceptable power Wb is greater than or equal to the predetermined value Wb1, the process proceeds to step S20. If the acceptable power Wb is less than the predetermined value Wb1, the process proceeds to step S30.

In step S20, as shown in the following equation (1), the required engine torque Pe is set to the required power generation torque Pgd.
Pe = Pgd (1)
The required power generation torque Pgd is a required value of the generator torque Pg, and is a torque required to drive the generator 9 according to a required output (required output power) of the generator 9.

Further, as shown in the following equation (2), the generator torque Pg is set to a value obtained by adding the speed F / B correction amount A (first torque correction amount) to the necessary power generation torque Pgd.
Pg = Pgd + A (2)
The speed F / B correction amount A is set according to the difference between the actual rotational speed of the input shaft of the generator 9 and the target rotational speed. In the present embodiment, since the input shaft of the generator 9 and the output shaft of the engine 2 are directly connected, the speed F / B correction amount A is determined by the speed between the actual rotational speed V and the target rotational speed Vt of the engine 2. What is necessary is just to set according to difference (DELTA) V (= V-Vt). The speed F / B correction amount A is a value obtained by adding a predetermined positive coefficient Cv to the speed difference ΔV. That is, when the speed difference ΔV is 0, the speed F / B correction amount A is 0, and the speed F / B correction amount A increases as the speed difference ΔV increases. When the speed difference ΔV is a negative value, the speed F / B correction amount A is also a negative value. Then, this routine ends.

In step S30, as shown in the following equation (3), the required engine torque Pe is set to a value obtained by adding the speed F / B correction amount C (third torque correction amount) to the required power generation torque Pgd.
Pe = Pgd + C (3)
Further, as shown in the following equation (4), the generator torque Pg is set to a value obtained by adding the speed F / B correction amount B (second torque correction amount) to the necessary power generation torque Pgd.

Pg = Pgd + B (4)
The speed F / B correction amount B is the limit value (maximum absolute value) of the speed F / B correction amount A described above, and is set to a value that does not exceed the output possible range of the generator torque Pg. The speed F / B correction amount C is a value obtained by subtracting the speed F / B correction amount B from the speed F / B correction amount A described above, as shown in the following equation (5).
C = A−B (5)
Then, this routine ends.

By controlling as described above, in the present embodiment, when the acceptable power Wb of the driving battery 11 is equal to or greater than the predetermined value Wb1 (normal time), the required engine torque Pe is set to the necessary power generation torque Pgd. The Thereby, the generator 9 driven by the engine 2 can generate the required amount of power.
Furthermore, by setting the generator torque Pg to a value obtained by adding the speed F / B correction amount A to the required power generation torque Pgd, a speed difference ΔV between the actual rotational speed V and the target rotational speed V of the engine 2 is generated. Sometimes the generator torque Pg is corrected. When the actual rotational speed V of the engine 2 is higher than the target rotational speed Vt, the speed F / B correction amount A becomes larger than 0, so that the generator torque Pg increases, and thus the load on the engine 2 increases. The actual rotational speed V of the engine 2 decreases. Further, when the actual rotational speed V of the engine 2 is smaller than the target rotational speed Vt, the speed F / B correction amount A becomes a negative value, so that the generator torque Pg decreases and the load on the engine 2 decreases. Thus, the actual rotational speed V of the engine 2 increases. Since the speed F / B correction amount A is set according to the speed difference ΔV between the actual rotational speed V and the target rotational speed Vt, the actual torque of the engine 2 is corrected by correcting the generator torque Pg according to the increase / decrease in the speed difference ΔV. The rotational speed V can be brought close to the target rotational speed Vt. Thus, since the actual rotational speed V of the engine 2 is controlled by controlling the generator torque Pg, a method of increasing or decreasing the required engine torque Pe of the engine 2 to make the actual rotational speed V of the engine 2 the target rotational speed Vt. Therefore, it is possible to perform rotation speed control with better responsiveness.

  Further, when the acceptable power Wb of the driving battery 11 is less than the predetermined value Wb1 (when the battery is insufficiently received), the generator torque Pg is a value obtained by adding the speed F / B correction amount B to the required power generation torque Pgd. Set to Since the speed F / B correction amount B is a limit value of the speed F / B correction amount A, it is within a possible range when a speed difference ΔV between the actual rotational speed V of the engine 2 and the target rotational speed Vt occurs. The generator torque Pg is corrected.

  Further, the required engine torque Pe is set to a value obtained by adding the speed F / B correction amount C to the required power generation torque Pgd, and the speed F / B correction amount C is a speed F / B necessary for eliminating the speed difference ΔV. Since this is a value obtained by subtracting the speed F / B correction amount B of the generator torque Pg from the correction amount A, the torque correction by the generator 9 is performed to the limit, and the shortage is compensated by correcting the required engine torque Pe. be able to.

3 and 4 are time charts showing an example of changes in the required engine torque Pe, the generator torque Pg, and the actual engine rotation speed V when the target rotation speed Vt of the engine 2 is decreased in the present embodiment. . FIG. 3 shows a normal time, and FIG. 4 shows a time when battery acceptance is insufficient.
When the control is performed so that the target rotational speed Vt of the engine 2 is smoothly lowered from V1 and shifted to V2, in the normal time when the acceptable power Wb of the driving battery 11 is equal to or greater than the predetermined value Wb1, as shown in FIG. The required engine torque Pe is maintained at the required power generation torque Pgd, and the generator torque Pg is reduced by the torque correction amount (speed F / B correction amount A) corresponding to the speed difference ΔV. Therefore, the required values of the drive torque of the engine 2 and the generator 9 shown by the broken line in FIG. 3 coincide with the generator torque Pg. By correcting the torque in this way, the actual rotational speed V of the engine 2 changes with high accuracy so as to coincide with the target rotational speed Vt.

  Further, when the battery acceptance is insufficient, as shown in FIG. 4, the generator torque Pg is corrected and reduced by the limit value of the torque correction amount (speed F / B correction amount B), and the required engine torque Pe is also reduced by the torque correction amount. It is corrected by (speed F / B correction amount C) and decreases. The total value of the torque correction amount (speed F / B correction amount C) of the engine 2 and the torque correction amount (speed F / B correction amount B) of the generator torque Pg is a correction amount (speed F) based on the speed difference ΔV. / B correction amount A) is set to be the same as that indicated by the broken line in FIG. 4, the required values of the drive torque of the engine 2 and the generator 9 can be reduced in the same manner as in the normal time. Therefore, even when the battery acceptance is insufficient, the actual rotational speed V of the engine 2 can be shifted so as to coincide with the target rotational speed Vt.

  As described above, when the speed difference ΔV between the actual rotational speed V of the engine 2 and the target rotational speed Vt occurs, the electric power Wb that can be received by the drive battery 11 is normal when the electric power Wb is not less than the predetermined value Wb1. The rotational speed with good responsiveness is controlled by the torque correction, and both the torque correction of the generator 9 and the torque correction of the engine 2 are performed when the acceptable power Wb is lower than the predetermined value Wb1 and the acceptance state is reduced. By changing, the actual rotational speed V of the engine 2 can be sufficiently controlled to the target rotational speed Vt even if the torque correction of the generator 9 is limited as the acceptable power Wb decreases. Therefore, the rotational speed of the engine 2 can be accurately controlled regardless of the power acceptance state of the drive battery 11.

  Furthermore, if the required engine torque Pe is suddenly increased or decreased, hunting may occur. Therefore, as shown in FIG. ) To suppress the change rate of the required engine torque Pe. Thereby, the hunting of the engine 2 can be suppressed and the rotation speed can be stabilized with high accuracy. The shortage of the torque correction amount generated by suppressing the change rate of the torque correction amount of the engine 2 may be compensated by increasing the torque correction amount (speed F / B correction amount B) of the generator 9. In the case of such control, it is desirable that the speed F / B correction amount B is set with a margin from the limit value. Therefore, a large change in the torque correction amount based on the rotational speed difference ΔV is handled by correcting the required engine torque Pe, and a fine change in the torque correction amount is handled by correcting the generator torque Pg. Thus, more accurate rotation speed control becomes possible.

In addition, this invention is not limited to the said embodiment. For example, in the above embodiment,
The acceptable power Wb of the driving battery 11 is calculated based on the charging rate SOC and the temperature, but the acceptable power Wb may be calculated from any one of the charging rate SOC and the temperature. The acceptable power Wb may be estimated from the above condition.
Further, the speed F / B correction amount B may be changed according to the acceptable power Wb. Specifically, the speed F / B correction amount B may be set to increase as the acceptable power Wb increases. As a result, the speed F / B correction amount B can be set larger, increasing the opportunity for torque correction using only the generator 9 and enabling more responsive rotational speed control.

  In the present embodiment, the present invention is applied to a plug-in hybrid vehicle that can be switched between the EV mode, the series mode, and the parallel mode. However, the generator is driven by the engine, and the engine load is controlled by controlling the load of the generator. The present invention can be widely applied to vehicles that can control the rotation speed.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Engine 9 Generator 10b Generator control unit (control means)
11 Battery for driving 11a Battery monitoring unit 20 Hybrid control unit (control means)
22 Engine control unit (control means)

Claims (4)

In a hybrid vehicle comprising an engine mounted on a vehicle, a generator that is driven by the engine to generate electric power, and a drive battery that is supplied with electric power and can be charged,
When the input shaft of the generator and the output shaft of the engine are in a direct connection state, the drive request torque of the engine is set to a required power generation torque according to the required output of the generator, and the generator drive The torque is set to a value obtained by correcting the required power generation torque with a first torque correction amount set according to the speed difference between the actual engine speed and the target engine speed, and the engine speed is controlled. An operation control device for a hybrid vehicle provided with a control means,
When the power acceptance state of the driving battery is reduced below a predetermined value, the control means sets the second torque correction amount based on the limit value of the first torque correction amount to the driving torque of the generator. The required power generation torque is set to a corrected value, and the engine drive request torque is set to a third torque correction amount that is a value obtained by subtracting the second torque correction amount from the first torque correction amount. An operation control device for a hybrid vehicle, wherein the control of the rotational speed of the engine is changed so as to set a necessary power generation torque to a corrected value. The power receiving state of the drive battery, the hybrid vehicle operation control apparatus according to claim 1, characterized in that it is determined based on the temperature of the driving battery. The power receiving state of the drive battery, the hybrid vehicle operation control apparatus according to claim 1, characterized in that it is determined based on the charging rate of the driving battery. The maximum rate of change of the third torque correction amount according to any one of claims 1 to 3, characterized in that it is set to be smaller than the maximum change rate of the second torque correction amount Control device for hybrid vehicles.

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