JP6582650B2 - Hybrid vehicle control device - Google Patents

Description

  The present invention relates to a hybrid vehicle control device that controls a hybrid vehicle.

Conventionally, drive systems such as a series system and a parallel system are known for hybrid vehicles equipped with an engine and a motor. There is also known a hybrid vehicle that can switch between these drive methods (series mode, EV (electric vehicle) mode, parallel mode, etc.) depending on the traveling state of the host vehicle.
Among these, in the series mode (series system), a generator is driven by an engine to generate electric power, and the electric power is used for charging a driving battery or driving a motor.
Here, the generator (generator) rotation speed feedback control that adjusts the engine rotation speed by increasing or decreasing the generator drive torque when the target rotation speed and the actual rotation speed of the engine deviate during the series mode. It is known (for example, refer to Patent Document 1 below).

JP 2014-133458 A

In the generator rotational speed feedback control, when the actual rotational speed of the engine is faster than the target rotational speed, power is generated by increasing the driving torque of the generator, thereby applying a load to the engine and lowering the rotational speed. At this time, since the required power generation amount for the generator exceeds the target power generation amount (power amount for driving the motor and driving battery) and becomes surplus power, it is necessary to input this surplus power to the battery.
Therefore, when the chargeable capacity of the drive battery is small, the engine speed may not be reduced.
In Patent Document 1 described above, when the chargeable capacity of the drive battery is small, the engine drive request torque is corrected together with the drive torque of the generator. However, the response to engine torque change is lower than that of the generator. There is a problem that it takes time to reach a desired rotation speed.
The present invention has been made in view of such circumstances, and an object thereof is to quickly control the rotational speed of the engine even when the chargeable capacity of the driving battery is small.

In order to achieve the above object, a hybrid vehicle control device according to the invention of claim 1 includes an engine mounted on a vehicle, a generator driven by the engine to generate electric power, and electric power supplied from the generator. A hybrid vehicle control device for controlling a hybrid vehicle comprising a rechargeable drive battery, wherein the engine drive request torque is set to a required power generation torque according to a required power generation amount for the generator, and Rotational speed control means for controlling the rotational speed of the engine by setting the driving torque of the generator to a value obtained by correcting the required power generation torque with a correction value based on the difference between the actual rotational speed and the target rotational speed of the engine When the battery condition detecting means for detecting a charging capacity of the driving battery, a fuel mosquito implementing fuel cut before SL engine Comprising a DOO control means, said fuel cut control means, wherein when the difference obtained by subtracting the target rotational speed from the actual rotation speed is the second predetermined value or more and the chargeable capacity of the first predetermined amount or less, And when the difference obtained by subtracting the target rotational speed from the actual rotational speed is equal to or greater than a second predetermined value, the chargeable capacity exceeds a first predetermined amount, and the correction value is equal to or greater than a third predetermined value. A fuel cut of the engine is performed, a difference obtained by subtracting the target rotational speed from the actual rotational speed is equal to or greater than a second predetermined value, the chargeable capacity exceeds a first predetermined amount, and the correction value is the third If less than the predetermined value, and the difference obtained by subtracting the target rotational speed from the actual rotation speed of the second to less than a predetermined value, does not perform the fuel cut of the engine, characterized by a crotch.
The hybrid vehicle control device according to a second aspect of the invention is characterized in that the battery state detection means detects the chargeable capacity based on a charging rate of the driving battery and a temperature of the driving battery. .

According to the present invention, in a hybrid vehicle for controlling the rotational speed of the engine by correcting the drive torque of the generator, the difference between the actual rotational speed and the target rotational speed of the engine relative to the charge capacity of the driving battery If it is large, cut the engine fuel. Therefore, when the chargeable capacity of the drive battery is small (full charge, low temperature, deterioration, etc.), it is advantageous in reducing the engine speed without increasing the charge rate of the drive battery. In addition, the engine rotational speed can be reduced in a short time compared to correcting the engine drive request torque together with the generator drive torque, which is advantageous in improving the response of the engine rotational speed control. .
According to the present invention, fuel cut is performed regardless of the chargeable capacity when the difference between the actual engine speed and the target engine speed is large and the correction value of the drive torque of the generator is equal to or greater than a predetermined value. Therefore, when the upper limit of the correction value of the generator rotational speed feedback control is reached, it is advantageous in quickly absorbing the difference and preventing the engine from over-rotating.
According to the present invention, since the chargeable capacity of the drive battery is detected based on the charge rate and temperature of the drive battery, it depends on the temperature as compared with the case where the chargeable capacity is detected using only the charge rate. This is advantageous in detecting a more accurate chargeable capacity that reflects changes in battery characteristics.

It is explanatory drawing which shows the structure of the hybrid vehicle 20 with which the hybrid vehicle control apparatus 10 concerning embodiment is applied. 2 is a block diagram illustrating a functional configuration of the hybrid vehicle control device 10. FIG. 3 is a flowchart showing an engine speed control process by the hybrid vehicle control device 10;

Exemplary embodiments of a hybrid vehicle control device according to the present invention will be explained below in detail with reference to the accompanying drawings.
FIG. 1 is an explanatory diagram illustrating a configuration of a hybrid vehicle 20 to which the hybrid vehicle control device 10 according to the embodiment is applied.
The hybrid vehicle 20 includes an engine 22 and a motor 24 that drive a drive shaft 38 of drive wheels (for example, front wheels 36).
The engine 22 can drive the generator 28 to generate electric power, and can rotate the drive shaft 38 of the front wheel 36 via the transmission 26 when the clutch 23 is engaged.
The electric power generated by the generator 28 is supplied to the driving battery 32 via the generator inverter 34 to charge the driving battery 32 or is used as electric power for driving the motor 24 via the motor inverter 30.
The generator inverter 34 incorporates a generator control unit 34A for controlling the generator 28. The generator control unit 34A receives a control signal from the hybrid vehicle control device 10 (ECU 40) (drive torque Tg of the generator 28 described later). Based on the above, the output (generated power) of the generator 28 is controlled.

In the present embodiment, the output shaft of the engine 22 and the input shaft of the generator 28 are directly connected. Therefore, the rotational speed of the output shaft of the engine 22 and the rotational speed of the input shaft of the generator 28 (hereinafter simply referred to as “the rotational speed of the engine 22” and “the rotational speed of the generator 28”) coincide.
However, the rotational speed of the engine 22 and the rotational speed of the generator 28 may not completely match due to errors due to performance variations of parts.
A clutch 23 is provided between the generator 28 and the transmission 26 so that the transmission of the driving force of the engine 22 can be switched.

The motor 24 is driven by being supplied with high-voltage power from the drive battery 32 and the generator 28 via the motor inverter 30, and rotates the drive shaft 38 of the front wheel 36 via the transmission 26.
The motor inverter 30 includes a motor control unit 30A that controls the motor 24. The motor control unit 30A controls the output of the motor 24 based on a control signal from a hybrid vehicle control device 10 (ECU 40) described later. .

The drive battery 32 is composed of a secondary battery such as a lithium ion battery, and has a battery module (not shown) in which a plurality of battery cells are configured. A voltmeter, an ammeter, a thermometer, and the like are connected to each battery cell and battery module, and the state of the drive battery 32 is detected based on these detection values.
The state of the drive battery 32 is detected by battery state detection means 44 described later. In the present embodiment, the battery state detection unit 44 is provided in the ECU 40, but the battery state detection unit 44 may be built in the driving battery 32.
The drive battery 32 is charged by using the power generated by the generator 28 or by supplying external power by connecting an external power source to a charging terminal (not shown).

FIG. 2 is a block diagram illustrating a functional configuration of the hybrid vehicle control device 10.
In the present embodiment, the ECU 40 functions as the hybrid vehicle control device 10.
The ECU 40 is a control unit that controls the entire hybrid vehicle 20, and includes a CPU, a ROM that stores and stores a control program, a RAM as an operation area of the control program, an EEPROM that holds various data in a rewritable manner, a peripheral circuit, and the like It includes an interface unit that interfaces with the.

  The ECU 40 includes a driving battery 32, an engine 22, a generator inverter 34 (more specifically, a generator control unit 34A), a motor inverter 30 (more specifically, a motor control unit 30A), a clutch 23, and an accelerator for detecting an accelerator operation amount. An opening degree sensor 33 is connected, and detection information and operation information of these devices are input.

  Further, the ECU 40 calculates a vehicle request output necessary for traveling of the hybrid vehicle 20 based on various detection amounts and various operation information from the devices, and controls the engine 22, the generator inverter 34, the motor inverter 30, and the clutch 23. A signal is transmitted to switch the running mode (EV mode, series mode, parallel mode), and the outputs of the engine 22, motor 24, and generator 28 are controlled.

Here, the traveling mode of the hybrid vehicle 10 will be described.
In the EV mode, the engine 22 is stopped and the motor 24 is driven by the electric power supplied from the drive battery 32 to run.
In the series mode, the clutch 23 is disengaged and all the driving force of the engine 22 is applied to the generator 28. Then, the motor 24 is driven by the electric power generated by the generator 28 to run. At this time, if the power generated by the generator 28 is insufficient for the required output to the motor 24, the power stored in the drive battery 32 is also used for driving the motor 24. Further, when the generated power of the generator 28 is larger than the required output for the motor 24, the surplus power is supplied to the driving battery 32 to charge the driving battery 32.

In the parallel mode, the power of the engine 22 and the power of the motor 24 are combined to drive the front wheels. That is, the clutch 23 is connected, the power of the engine 22 is transmitted to the drive shaft 38 via the transmission 26 to drive the front wheels 36, and the power generated by operating the generator 28 by the engine 22 and the drive battery 32. The motor 24 is driven by the electric power supplied from the vehicle.
The ECU 40 sets the traveling mode to the parallel mode in a region where the engine 22 is efficient, such as during high-speed traveling. Further, in the region excluding the parallel mode, that is, in the middle / low speed traveling mode, the mode is switched between the EV mode and the series mode based on the charging rate of the driving battery 32.
In addition, when the charging rate of the driving battery 32 falls below the allowable range, the ECU 40 drives the engine 22 in the series mode to generate electric power with the generator 28 to charge the driving battery 32.

The ECU 40 controls the drive torque Tg of the generator 28 and the drive request torque Te of the engine 22 in a state where the engine 22 is disconnected from the drive shaft 38 and drives the generator 28 as in the series mode. It has a function of adjusting the rotational speed V to the target rotational speed Vt.
The details will be described below.

The ECU 40 implements a rotation speed control means 42, a battery state detection means 44, and a fuel cut control means 46 by the CPU executing the control program.
The rotational speed control means 42 sets the required drive torque Te of the engine 22 to the required generated torque Tgd corresponding to the required power generation amount for the generator 28, and sets the drive torque Tg of the generator 28 to the actual rotational speed of the engine 22. The required power generation torque Tgd is set to a value corrected by the correction value A based on the difference between the engine speed and the target rotation speed, and the rotation speed of the engine 22 is controlled.
That is, the rotational speed control means 42 controls the rotational speed of the engine by generator rotational speed feedback control.

Details of the generator rotational speed feedback control will be described.
First, the rotational speed control means 42 calculates a required power generation torque Tgd, which is a torque of the generator 28 necessary for obtaining a required power generation amount for the generator 28.
Then, the drive required torque Te of the engine 22 is set to the necessary power generation torque Tgd ( T e = T gd).

On the other hand, the drive torque Tg of the generator 28 is set to a value obtained by correcting the required power generation torque Tgd with a correction value A based on the difference between the actual rotational speed of the generator 28 and the target rotational speed.
In this embodiment, a value obtained by adding the required power generation torque Tgd the correction value A, set as a drive torque Tg of the generator 28 (T g = T gd + A).
The correction value A is set according to the difference between the actual rotational speed of the engine 22 and the target rotational speed. In this embodiment, since the input shaft of the generator 28 and the output shaft of the engine 22 are directly connected, the correction value A is the speed difference ΔV between the actual rotational speed V of the generator 28 and the target rotational speed Vt of the engine 22. What is necessary is just to set according to (= V-Vt).
The correction value A is obtained by adding a predetermined positive coefficient Cv to the speed difference ΔV. That is, when the speed difference ΔV is 0, the correction value A is 0, and the correction value A increases as the speed difference ΔV increases (the actual rotation speed becomes faster than the target rotation speed). When the speed difference ΔV is a negative value (the actual rotational speed is slower than the target rotational speed), the correction value A is a negative value.

By setting the required power generation torque Tgd as drive request torque Te of the engine 22 (T e = T gd) , thereby enabling power generation with required power generation amount of power at the power generator 28 driven by the engine 22.
Further, the driving torque Tg of the generator 28, by setting a value obtained by adding the correction value A (T g = T gd + A) required generation torque Tgd, the actual rotation speed V and the target rotation speed Vt of the engine 22 When the speed difference ΔV occurs, the drive torque Tg of the generator 28 is corrected.
When the actual rotational speed V of the engine 22 is higher than the target rotational speed Vt, the correction value A is greater than 0, so that the drive torque Tg of the generator 28 increases, and thus the load on the engine 22 increases, and the engine 22 The actual rotation speed V is reduced.
Further, when the actual rotational speed V of the engine 22 is slower than the target rotational speed Vt, the correction value A becomes a negative value, so that the torque Tg of the generator 28 decreases, the load on the engine 22 decreases, The actual rotational speed V of the engine 22 increases.
Since the correction value A is set according to the speed difference ΔV between the actual rotational speed V and the target rotational speed Vt, the actual rotation of the engine 22 is corrected by correcting the driving torque Tg of the generator 28 according to the increase / decrease of the speed difference ΔV. The speed V can be brought close to the target rotational speed Vt.

  In the generator rotational speed feedback control, the actual rotational speed V of the engine 22 is controlled by changing the driving torque Tg of the generator 28. Therefore, the actual rotational speed V of the engine 22 is increased or decreased by increasing or decreasing the required driving torque Te of the engine 22. Rotational speed control with better responsiveness than the method of setting to the target rotational speed Vt can be performed.

The battery state detection unit 44 detects the chargeable capacity Pc of the drive battery 32.
The battery state detection unit 44 monitors the charge rate (State of Charge, hereinafter referred to as SOC) of the drive battery 32, the battery temperature, and the like, and calculates the chargeable capacity Pc of the drive battery 32 from the charge rate and the battery temperature. To do. The chargeable capacity Pc is the maximum power that can be charged (input) to the drive battery 32, and has a tendency to decrease as the charging rate increases and to decrease as the battery temperature decreases. ing.
For example, a map of the chargeable capacity Pc with respect to the charging rate and the battery temperature is stored in the battery state detection unit 44 in advance, and the chargeable capacity Pc of the drive battery 32 can be obtained using this map.

The fuel cut control means is configured such that the chargeable capacity Pc of the drive battery 32 is equal to or less than a first predetermined amount Px and the difference ΔV between the actual rotational speed V of the engine 22 and the target rotational speed Vt is equal to or greater than a second predetermined value Vx In addition, the fuel cut of the engine 22 is performed.
As described above, the rotational speed control means 42 corrects the torque Tg of the generator 28 to correct the actual rotational speed V when there is a difference ΔV between the actual rotational speed V of the engine 22 and the target rotational speed Vt. Although control is performed so as to approach the target rotation speed Vt, when the actual rotation speed V is faster than the target rotation speed Vt (ΔV> 0), surplus power (power exceeding the required power generation amount) is generated in the generator 28. Therefore, it is necessary to input surplus power to the drive battery 32.
On the other hand, when the chargeable capacity of the driving battery 32 is small, this surplus power may not be accepted.
Therefore, when there is a possibility that the surplus power of the generator 28 cannot be charged in the drive battery 32, the fuel of the engine 22 is cut, and the torque of the engine 22 is reduced by mechanical friction to reduce the rotational speed. Let

  The first predetermined amount Px and the second predetermined value Vx may be fixed values or may be determined by a function having one as an independent variable and the other as a dependent variable (for example, Px = f ( Vx)). That is, as the difference ΔV between the actual rotation speed V and the target rotation speed Vt is larger, the surplus power amount is larger, so that it is desirable to perform the fuel cut while the chargeable capacity Pc is large. Therefore, the first predetermined amount Px and the second predetermined value Vx may be set by setting a function that increases the first predetermined amount Px as the second predetermined value Vx increases.

Further, the fuel cut control means 46 performs the fuel cut regardless of the chargeable capacity when the correction value A set for the drive torque Tg of the generator 28 is equal to or greater than the third predetermined value Ax.
This is based on the assumption that a large rotational speed difference that is difficult to absorb by correcting the driving torque Tg of the generator 28 occurs. It is assumed that the rotational speed of the generator 28 does not match.
The third predetermined value Ax is, for example, a value that can be determined that the correction amount A of the driving torque Tg of the generator 28 exceeds the tolerance range that takes into account the component variations of the engine 22 and the generator 28.
When a large rotational speed difference is absorbed by correcting the driving torque Tg of the generator 28, the rotational speed difference of the engine 22 cannot be converged and the overspeed continues. As in the present embodiment, when the rotational speed difference is large, the actual rotational speed V can be matched with the target rotational speed Vt within a short period of time by controlling the rotational speed by fuel cut. The comfort of 20 can be further improved.

FIG. 3 is a flowchart showing an engine speed control process by the hybrid vehicle control device 10.
The hybrid vehicle control device 10 repeatedly executes the process shown in FIG. 3 while the hybrid vehicle 20 is traveling.
When the hybrid vehicle 20 is in the series mode (step S300: Yes), the hybrid vehicle control device 10 causes the rotation speed control means 42 to set the difference ΔV between the actual rotation speed V of the engine 22 and the target rotation speed Vt to a second predetermined value. It is determined whether or not the value is greater than or equal to the value Vx (step S302).

When the difference ΔV between the actual rotation speed V and the target rotation speed Vt is equal to or greater than the second predetermined value Vx (step S302: Yes), the chargeable capacity Pc of the drive battery 32 is detected by the battery state detection means 44. (Step S304). Then, the rotation speed control means 42 determines whether or not the chargeable capacity Pc is equal to or less than the first predetermined amount Px (step S306).
When the chargeable capacity Pc is equal to or less than the first predetermined amount Px (step S306: Yes), the process proceeds to step S310, and the fuel cut of the engine 22 is performed by the fuel cut control means 46 (step S310).

When the chargeable capacity exceeds the first predetermined amount Px (step S306: No), the rotational speed control means 42 determines that the correction value A of the driving torque Tg of the generator 28 is equal to or greater than the third predetermined value Ax. It is determined whether or not (step S308).
When the correction value A of the driving torque Tg of the generator 28 is not less than the third predetermined value Ax (step S308: Yes), the fuel cut of the engine 22 is performed by the fuel cut control means 46 (step S310).

On the other hand, if the difference ΔV between the actual rotational speed V and the target rotational speed Vt is less than the second predetermined value Vx in step S302 (step S302: No), or the correction value of the driving torque Tg of the generator 28 in step S308. When A is less than the third predetermined value Ax (step S308: No), the process proceeds to step S312 and the rotation speed control means 42 performs normal torque setting (step S312).
That is, to set the required power generation torque Tgd as drive request torque Te of the engine 22 with (T e = T gd), the driving torque Tg of the generator 28 is set to a value obtained by adding the correction value A to the required power generation torque Tgd (T g = T gd + A ).

As described above, the hybrid vehicle control apparatus 10 according to the embodiment includes the hybrid vehicle 20 that performs the generator rotational speed feedback control that controls the rotational speed of the engine 22 by correcting the driving torque of the generator 28. When the difference between the actual rotational speed V of the engine 22 and the target rotational speed Vt is larger than the chargeable capacity of the drive battery 32, the fuel of the engine 22 is cut. Therefore, it is advantageous in reducing the rotation speed of the engine 22 without increasing the charging rate of the drive battery 32 when the chargeable capacity of the drive battery 32 is small (full charge, low temperature, deterioration, etc.). It becomes. In addition, the rotational speed of the engine 22 can be reduced in a short time compared with the case where the required driving torque of the engine 22 is corrected together with the driving torque of the generator 28, and the responsiveness of the engine rotational speed control is improved. It will be advantageous.
Further, the hybrid vehicle control device 10 has a chargeable capacity when the difference between the actual rotational speed V of the engine 22 and the target rotational speed Vt is large and the correction value A of the driving torque of the generator 28 is equal to or greater than a predetermined value Ax. Regardless of the fuel cut. Therefore, when the upper limit of the correction value of the generator rotational speed feedback control is reached, it is advantageous in quickly absorbing the difference and preventing the engine 22 from over-rotating.
Further, since the hybrid vehicle control device 10 detects the chargeable capacity of the drive battery 32 based on the charge rate and battery temperature of the drive battery 32, it is compared with a case where the chargeable capacity is detected using only the charge rate. Thus, it is advantageous in detecting a more accurate chargeable capacity that reflects changes in battery characteristics due to battery temperature.

In addition, this invention is not limited to the said embodiment.
For example, in the above embodiment, the chargeable capacity of the drive battery 32 is detected based on the charge rate and the battery temperature, but the chargeable capacity may be detected from either the charge rate or the battery. However, the chargeable capacity may be detected from other conditions.
In the present embodiment, the present invention is applied to the hybrid vehicle 10 capable of switching between the EV mode, the series mode, and the parallel mode. However, the generator 28 is driven by the engine 22 and the load on the generator 28 is controlled. The present invention can be widely applied to vehicles that can control the rotation speed of the engine 22.

  DESCRIPTION OF SYMBOLS 10 ... Hybrid vehicle control apparatus, 20 ... Hybrid vehicle, 22 ... Engine, 23 ... Clutch, 24 ... Motor, 26 ... Transmission, 28 ... Generator, 30 ... Motor inverter, 30A ... Motor Control unit, 32... Drive battery, 33... Accelerator opening sensor, 34... Generator inverter, 34 A... Generator generator unit, 36 .. front wheel, 38 .. drive shaft, 40. Rotational speed control means 44... Battery state detection means 46. Fuel cut control means.

Claims (2)

A hybrid vehicle control device that controls a hybrid vehicle comprising: an engine mounted on a vehicle; a generator that is driven by the engine to generate power; and a drive battery that is supplied with power from the generator and can be charged. And
The engine drive request torque is set to a required power generation torque corresponding to the required power generation amount for the generator, and the generator drive torque is corrected based on the difference between the actual engine speed and the target engine speed. A rotational speed control means for controlling the rotational speed of the engine by setting a value obtained by correcting the required power generation torque by a value;
Battery state detecting means for detecting a chargeable capacity of the driving battery;
Comprising a fuel cut control means for performing fuel cut before SL engine, a,
The fuel cut control means is configured such that the difference obtained by subtracting the target rotational speed from the actual rotational speed is equal to or greater than a second predetermined value and the chargeable capacity is equal to or smaller than a first predetermined amount, and from the actual rotational speed to the target When the difference obtained by subtracting the rotational speed is equal to or greater than a second predetermined value, the chargeable capacity exceeds a first predetermined amount, and the correction value is equal to or greater than a third predetermined value, the engine fuel cut is performed. A difference obtained by subtracting the target rotation speed from the actual rotation speed is equal to or greater than a second predetermined value, the chargeable capacity exceeds a first predetermined amount, and the correction value is less than the third predetermined value; and When the difference obtained by subtracting the target rotational speed from the actual rotational speed is less than the second predetermined value, the fuel cut of the engine is not performed.
The hybrid vehicle control device comprising a call. The battery state detection means detects the chargeable capacity based on a charging rate of the driving battery and a temperature of the driving battery.
The hybrid vehicle controller according to claim 1, wherein a.

Images