JP2020083232A - Control device for hybrid vehicle - Google Patents

Abstract

To provide a control device for a hybrid vehicle which suppresses rattling noise in a gear mechanism while maintaining battery performance.SOLUTION: A control device 10 is applied to a hybrid vehicle 1 including: a motor generator 3 functioning as an electric motor and a power generator; an engine 5 connected to the motor generator 3 via a gear mechanism 4; and a battery 9 for transferring power between itself and the motor generator 3. The control device 10 is provided with an acquisition section 27, a calculation section 28, and a control section 29. The acquisition section 27 acquires information on a charging rate SOC and a temperature T of the battery 9. The calculation section 28 calculates inputtable power P of the battery 9 on the basis of the charging rate SOC and the temperature T. In the operation range of the engine 5 where rattling noise in the gear mechanism 4 may occur, the control section 29 regeneratively drives the motor generator 3 when the inputtable power P exceeds a prescribed value P, and power-drives the motor generator 3 when the inputtable power P is equal to or less than the prescribed value P.SELECTED DRAWING: Figure 2

Description

The present invention relates to a control device for a hybrid vehicle in which an engine and a motor generator are connected via a gear mechanism.

2. Description of the Related Art Conventionally, in a hybrid vehicle in which an engine and a motor generator are connected via a gear mechanism, a technique is known in which the rattle noise of the gear mechanism is suppressed by controlling the operating state of the motor generator. That is, the motor generator is controlled to the power running side or the regenerative side to suppress the noise and vibration on the tooth contact due to the backlash (gear gap). For example, the motor generator is controlled to the power running side when the remaining capacity of the drive battery of the motor generator has a margin, and is controlled to the regeneration side when there is no margin (see Patent Documents 1 to 4). By such control, the gear on the motor generator side rotates in a state of being pressed in the forward rotation direction or the reverse rotation direction against the gear on the engine side, and noise and vibration are suppressed.

International Publication No. 2014/087483 JP 2008-162397 A JP 2004-328824 JP JP 2004-169842 JP

In the above technique, the power of the drive battery is consumed when the motor generator is controlled to the power running side, and the generated power is charged to the drive battery when the motor generator is controlled to the regeneration side. On the other hand, when the temperature of the drive battery is low, such control may accelerate deterioration of the drive battery. For example, when a lithium ion secondary battery is charged in an extremely low temperature environment, lithium dendrites are deposited on the negative electrode regardless of the size of the remaining capacity, and battery performance is likely to deteriorate.

One of the objects of the present invention was devised in view of the above problems, and to provide a control device for a hybrid vehicle capable of suppressing gear rattle noise of a gear mechanism while maintaining battery performance. Is. It should be noted that the present invention is not limited to this purpose, and it is also possible to obtain operational effects that are derived from the respective configurations shown in "Modes for carrying out the invention" to be described later, and which cannot be obtained by conventional techniques. Can be positioned as a purpose.

(1) A control device for a hybrid vehicle disclosed herein exchanges electric power between a motor generator functioning as an electric motor and a generator, an engine connected to the motor generator via a gear mechanism, and the motor generator. And a battery that operates. The device includes an acquisition unit that acquires information on the charging rate and temperature of the battery, and a calculation unit that calculates the inputtable electric power of the battery based on the charging rate and the temperature. Further, in the operating region of the engine in which gear rattling noise of the gear mechanism may occur, when the inputtable electric power exceeds a predetermined value, the motor generator is regeneratively driven, and the inputtable electric power is below a predetermined value. And a control unit for driving the motor generator to perform power running.

(2) It is preferable that the calculation unit calculates the soundness of the battery and also calculates the inputtable electric power based on the charging rate, the temperature, and the soundness.
(3) It is preferable that the control unit sets the torque of the motor generator to be larger as the rotation speed of the engine is slower.

By selectively using the power running drive and the regenerative drive of the motor generator by using the inputtable electric power calculated based on the temperature of the battery, it is possible to reliably suppress the rattling noise of the gear mechanism while maintaining the battery performance.

It is a schematic diagram which illustrates the composition of the hybrid vehicle to which the control device is applied. It is a block diagram for explaining a configuration of a control device. (A) and (B) are examples of graphs for setting the first gain and the second gain. It is a graph which illustrates the relationship between the torque set up with a control device, and the number of rotations. It is a flow chart which illustrates the procedure of control performed by a control device.

[1. Constitution]
The control device 10 of the present embodiment is applied to the vehicle 1 shown in FIG. This vehicle 1 is a hybrid vehicle equipped with a motor 2, a generator 3 (motor generator), and an engine 5. The motor 2 and the generator 3 are motor generators each having a function as an electric motor and a function as a generator. The motor 2 is mainly used to generate the driving force of the vehicle 1 and regeneratively generates electric power when the vehicle 1 is decelerated. The generator 3 is not only used to generate power with the driving force of the engine 5, but can also start the engine 5 and generate the driving force of the vehicle 1 together with the motor 2 and the engine 5.

The engine 5 is an internal combustion engine such as a gasoline engine or a diesel engine, and drives a rotating shaft by burning an air-fuel mixture containing fuel (gasoline, light oil, etc.) in a combustion chamber. The driving force generated by the engine 5 is used to cause the generator 3 to generate electric power or to drive the driving wheels. The engine 5 of the present embodiment also has the functions of a heat source and a power source of the air conditioning system. For example, the driving force of the engine 5 is used to rotationally drive the air conditioner compressor. The waste heat (exhaust heat) of the engine 5 is used for heating the vehicle interior.

As shown in FIG. 1, a gear mechanism 4 is provided on a power transmission path connecting the engine 5 and the generator 3. The gear mechanism 4 functions to transmit the rotation of the engine 5 to the generator 3 side at a predetermined gear ratio (reduction ratio). In other words, the rotation of the generator 3 is transmitted to the engine 5 side at a ratio corresponding to the reciprocal of this gear ratio. Further, a clutch 8 is provided on the power transmission path connecting the engine 5 and the drive wheels. The generator 3 is connected to the power transmission path on the engine 5 side of the clutch 8, and the motor 2 is connected to the power transmission path on the drive wheel side of the clutch 8. By disengaging (disengaging) the clutch 8, the generator 3 and the engine 5 become independent from the drive wheels.

When the vehicle 1 is driven only by the motor 2 (for example, in the EV traveling mode), or when the engine 5 generates electric power while the vehicle 1 is driven by the motor 2 (for example, in the series traveling mode), the clutch 8 is Be released. On the other hand, when the vehicle 1 is run only by the engine 5 (for example, in the ENG running mode), or when the vehicle 1 is run by using the engine 5 and the motor 2 together (and the generator 3 if necessary) (for example, In the parallel traveling mode), the clutch 8 is closed (connected).

A battery 9 for driving is electrically connected to each of the motor 2 and the generator 3. The battery 9 is a battery (secondary battery) capable of exchanging electric power with each of the motor 2 and the generator 3. Specific examples of the battery 9 include a lithium ion secondary battery, a solid lithium ion battery, a graphene secondary battery, and a flow battery. The main function required for the battery 9 is to supply electric power for driving the motor 2 and the generator 3 and store the generated electric power generated by the motor 2 and the generator 3. The battery 9 of the present embodiment can be externally charged by an external power feeding device, and an inlet (charging port) for external charging is provided on the side surface of the vehicle 1. The battery 9 can be externally charged by inserting the charging gun connected to the external power supply device into the inlet.

An inverter 6 is provided on the electric circuit that connects the motor 2 and the battery 9. The inverter 6 is a converter (AC-DC inverter) for mutually converting DC power on the battery 9 side and AC power on the motor 2 side. Each inverter 6, 7 has a built-in three-phase bridge circuit including a plurality of switching elements. AC power is generated by intermittently switching the connection state of each switching element. Further, by controlling the switching frequency and the output voltage, the outputs (torque, rotation speed) of the motor 2 and the generator 3 are adjusted. The operating states of the motor 2, the generator 3, and the inverters 6 and 7 are controlled by the control device 10 (ECU).

The control device 10 is an electronic control device (computer) for performing control for suppressing rattling noise of the gear mechanism 4 while maintaining good performance of the battery 9. As shown in FIG. 2, the control device 10 includes a processor 21 (central processing unit), a memory 22 (main memory), a storage device 23 (storage), and an interface device 24, which are connected via an internal bus 25. Connected. The processor 21 is a central processing unit that incorporates a control unit (control circuit), an arithmetic unit (arithmetic circuit), a cache memory (register group), and the like.

The memory 22 is a storage device that stores programs and data during work, and includes, for example, a ROM (Read Only Memory) and a RAM (Random Access Memory). The storage device 23 is a storage that stores data and firmware that is retained for a longer period of time than the memory 22, and includes, for example, a nonvolatile memory such as a flash memory or an EEPROM. The interface device 24 is a device including an I/O (Input and Output) circuit that controls input/output between the control device 10 and the outside, and bidirectionally exchanges information exchanged between the processor 21 and various peripheral devices. It has a function to translate (convert) into.

An engine speed sensor 11, a temperature sensor 12, a voltage sensor 13, a current sensor 14, an accelerator opening sensor 15, a vehicle speed sensor 16, and an inverter 7 are connected to the control device 10 via an interface device 24. The engine speed sensor 11 is a sensor that detects the engine speed N (the number of rotations per unit time, the rotation speed), and the temperature sensor 12 detects the temperature of the battery 9 (cell temperature, module temperature, casing temperature, etc.). It is a sensor.

The voltage sensor 13 is a sensor that detects the voltage (terminal voltage) of the battery 9, and the current sensor 14 is a sensor that detects the input/output current of the battery 9. The accelerator opening sensor 12 is a sensor that outputs a signal corresponding to the accelerator opening (depression amount of the accelerator pedal), and the vehicle speed sensor 13 is a sensor that outputs a signal corresponding to the traveling speed (vehicle speed) of the vehicle 1. The control device 10 of the present embodiment controls the operation state of the generator 3 by controlling the inverter 7 based on the information detected by the various sensors described above.

[2. control]
In the operating region of the engine 5 in which gear rattle noise of the gear mechanism 4 may be generated, the control device 10 carries out control to drive the generator 3 to perform power running and regenerative drive in order to suppress the gear rattle noise. The driving range in which the rattling noise can be generated is a driving range in which the engine speed N is equal to or lower than a predetermined value N _{0 in the} running mode (ENG running mode, series running mode, parallel running mode) in which the engine 5 is operating. is there. The predetermined value N ₀ may be, for example, a fixed value set within the range of 500 to 1500 [rpm] (idling rotation range), or depending on the drive torque or friction loss input from the engine 5 to the gear mechanism 4. It may be a variable value that is set.

The contents of control executed by the control device 10 are described in the control program 26 as software. Each element included in the control program 26 shown in FIG. 2 is a functional classification of its contents. The control program 26 includes an acquisition unit 27, a calculation unit 28, and a control unit 29. Note that instead of software, it is also possible to realize the same control by using hardware (logical circuit) that executes processing equivalent to these elements.

The acquisition unit 27 has a function of acquiring at least information on the SOC (State Of Charge) and the temperature T of the battery 9. The charge rate SOC is a percentage of the current charge amount [Ah] with respect to the full charge capacity [Ah] of the battery 9, and is estimated based on the charge/discharge characteristics of the battery 9 (for example, integrated value of voltage and current). It The temperature T mentioned here is the temperature of the electrolytic solution involved in the charge/discharge reaction of the battery 9, and is estimated based on the temperature (cell temperature, module temperature, casing temperature, etc.) detected by the temperature sensor 12. ..

The acquisition unit 27 also acquires the state of health SOH (State Of Health) of the battery 9. The soundness SOH is the percentage of the full charge capacity [Ah] of the battery 9 at the time of the new article to the full charge capacity [Ah], and is a parameter which is sometimes called health degree or deterioration degree. The full charge capacity [Ah] at the time of a new product is a fixed value set (measured) in advance. The full charge capacity [Ah] at that time can be calculated, for example, as an integrated value of currents charged from the empty state of the battery 9 to the full charged state. Alternatively, the full charge capacity [Ah] at that time may be estimated from the usage time of the battery 9. A well-known method can be adopted as a specific method of calculating the charging rate SOC and the soundness SOH. In the present embodiment, it is assumed that the “full charge capacity [Ah]” related to the calculation of the state of charge SOC is a fixed value.

The calculation unit 28 has a function of calculating the inputtable electric power P of the battery 9 based on at least the charging rate SOC and the temperature T acquired by the acquisition unit 27. The inputtable electric power P means the amount of electricity [Ah] (or the amount of electricity [Wh]) that can be stored without deteriorating the battery 9. The inputtable electric power P is smaller as the charging rate SOC is higher, and is larger as the charging rate SOC is lower. Further, the lower the temperature T, the smaller the value, and the higher the temperature T, the larger the value.

The calculation unit 28 of the present embodiment calculates the inputtable electric power P in consideration of not only the charging rate SOC and the temperature T but also the soundness SOH. The inputtable electric power P is set to a smaller value as the soundness SOH is lower. For example, the chargeable amount of electricity X[Ah] required to bring the battery 9 into the fully charged state is calculated based on the full charge capacity [Ah] and the state of charge SOC. On the other hand, the first gain K ₁ that decreases as the soundness SOH decreases and the second gain K ₂ that decreases as the temperature T decreases are set within the range of 0<K ₁ ≦1, 0<K ₂ ≦1. .. After that, the product of the chargeable electricity amount X, the first gain K ₁ and the second gain K ₂ is calculated as the inputtable electric power P.

Graphs used for setting the first gain K ₁ and the second gain K ₂ are illustrated in FIGS. 3(A) and 3(B). The first gain K ₁ in the present embodiment is set in a range equal to or less than a value (SOH/100) obtained by converting the soundness SOH expressed as a percentage into a decimal. That is, the value of the first gain K ₁ is set in the range below the broken line shown in FIG. As a result, as the deterioration of the battery 9 is small and in a healthy state, the value of the inputtable electric power P is calculated more carefully (higher safety factor), and the promotion of deterioration is suppressed. The graph of the second gain K ₂ is set so that the higher the temperature T, the closer to 1.0, and the lower the temperature, the closer to 0.

The control unit 29 has a function of controlling the operating state of the generator 3 based on the inputtable electric power P. The operating state here includes a powering drive state and a regenerative drive state (power generation state). When the inputtable electric power P exceeds the predetermined value P ₀ , the control unit 29 determines that the regenerative electric power can be stored in the battery 9 without difficulty, and regeneratively drives the generator 3. On the other hand, when the inputtable electric power P is less than or equal to the predetermined value P ₀ , the generator 3 is power-driven. As a result, storage of electricity in the state where the charge acceptance of the battery 9 is low is prevented, and deterioration of the battery 9 is suppressed. Even if the state of charge SOC of the battery 9 is relatively low, the deterioration of the battery 9 due to charging progresses in an extremely low temperature environment. In order to solve such a problem, in the present embodiment, the lower the temperature T, the smaller the inputtable electric power P becomes, and it becomes easier to prevent the battery 9 from being unreasonably charged. Therefore, the deterioration of the battery 9 is more effectively suppressed as compared with the existing control based on only the charging rate SOC.

Prerequisites for the control unit 29 to control the operating state of the generator 3 include at least that the engine 5 is operating in an operating range in which gear rattling noise can occur, and specifically, the engine speed N Is less than or equal to a predetermined value N ₀ . On the contrary, in the operating region where the engine speed N exceeds the predetermined value N ₀ , gear rattling noise is hardly generated in the gear mechanism 4, so that it is not necessary to operate the generator 3, but it is necessary to stop the generator 3. is not. For example, in a situation in which it is desired to operate the generator 3 at the request of another vehicle-mounted control device (for example, a situation in which the charge amount of the battery 9 is desired to be increased or a drive torque in the vehicle 1 is desired to be further increased), the engine rotation speed is increased. In a situation where the number N exceeds the predetermined value N ₀ , the control unit 29 may drive the generator 3 by power running or regenerative driving.

The magnitude of the regenerative torque when the generator 3 is regeneratively driven and the magnitude of the power running torque when the powering is performed may be fixed so that at least the rattling noise generated in the gear mechanism 4 is suppressed below a predetermined noise level. Good. On the other hand, the rattling noise of the gear mechanism 4 is more likely to occur as the engine speed N is lower. Therefore, the torque (regenerative torque, power running torque) of the generator 3 may be set according to the engine speed N. For example, as shown in FIG. 4, the lower the engine speed N, the larger the torque of the generator 3 is set. By increasing the torque of the generator 3, the gear on the generator 3 side in the gear mechanism 4 is pressed against the gear on the engine 5 side more strongly, and it is possible to prevent rattling noise.

The magnitudes of the regenerative torque and the power running torque set for the same engine speed N are the same. For example, when the value of the power running torque corresponding to the predetermined engine speed N ₁ is T ₁ , the value of the regenerative torque corresponding to the engine speed N ₁ is −T ₁ . With such a setting, the difference between the surface pressure during powering of the generator 3 and the surface pressure during regeneration can be reduced (set to zero), and uneven wear can be prevented. Also, the load of the generator 3 on the engine 5 can be made substantially the same during power running and during regeneration, and the operational stability of the engine 5 can be improved.

If the torque of the generator 3 (regenerative torque, power running torque) is too small, gear rattling noise is likely to occur. In other words, as shown in FIG. 4, the torque of the generator 3 (regenerative torque, power running torque) is utilized by utilizing the relationship between the torque and the engine speed N whose absolute value falls within a range larger than the predetermined value E _0. Is preferably set.

[3. flowchart]
FIG. 5 is an example of a flowchart for controlling the operating state of the generator 3. This flow is repeatedly executed at a predetermined cycle while the engine 5 is operating. First, various information used for control is input to the control device 10 (step A1). The acquisition unit 27 acquires information on the charging rate SOC, the soundness SOH, and the temperature T of the battery 9 based on the information. In addition, information on the engine speed N is also acquired.

If the generator 3 is already generating electricity, the calculator 28 calculates the regenerative torque E (step A2). The regenerative torque E is calculated based on the rotation speed of the generator 3 and the operating state of the inverter 7. Further, the calculation unit 28 calculates the inputtable electric power P of the battery 9 based on the charging rate SOC, the soundness SOH, and the temperature T (step A3). For example, the chargeable amount of electricity X is calculated based on the state of charge SOC, and the first gain K ₁ and the second gain K ₂ are calculated based on the soundness SOH and the temperature T. The product of these is the inputtable power P.

Subsequently, the control unit 29 determines whether the engine speed N is equal to or less than the predetermined value N ₀ (step A4). Here, if N>N ₀ , gear rattling noise is hardly generated in the gear mechanism 4, so this flow is ended without controlling the operating state of the generator 3. If N≦N ₀ , it is determined whether the regenerative torque E is equal to or less than the predetermined value E ₀ (step A5). When E>E ₀ , it is determined that the gear rattling noise hardly occurs in the gear mechanism 4, and this flow is ended without further controlling the operating state of the generator 3 (while maintaining the power generating state).

When E≦E _{0 in} step A5, it is determined whether or not the inputtable electric power P is equal to or less than the predetermined value P ₀ (step A6). Here, when P≦P ₀ , the power running torque corresponding to the engine speed N is set (step A7), and the generator 3 is power running driven (step A8). As a result, storage of electricity in the state where the charge acceptance of the battery 9 is low is prevented, and deterioration of the battery 9 is suppressed. On the other hand, when P>P ₀ , the regenerative torque corresponding to the engine speed N is set (step A9), and the generator 3 is regeneratively driven (step A10). As a result, the electric power generated by the generator 3 is stored in the generator 3.

In the above control, the charging rate SOC is gradually increased by regeneratively driving the generator 3. As a result, the inputtable electric power P gradually decreases, and when the electric power P becomes equal to or less than the predetermined value P ₀ , the generator 3 is power-driven. On the other hand, by driving the generator 3 to perform power running, the state of charge SOC gradually decreases. As a result, the inputtable electric power P gradually increases, and the generator 3 is regeneratively driven when it exceeds the predetermined value P ₀ . In this way, the operating state of the generator 3 is controlled to power running and regeneration so that the inputtable electric power P becomes substantially constant (in other words, the charging rate SOC is maintained within a substantially constant range). .

[4. Action, effect]
(1) In the control device 10 described above, the inputtable electric power P is calculated based on the charging rate SOC and the temperature T of the battery 9. Further, the power running drive and the regenerative drive of the generator 3 are selectively used based on the inputtable electric power P. By such control, the rattling noise of the gear mechanism 4 can be reliably suppressed while maintaining the battery performance. For example, when the engine speed N becomes a predetermined value N ₀ or less in an extremely low temperature environment (−20° C.) where the state of charge SOC is relatively low (40 to 60%), in the conventional control system, the generator 3 is There is a risk that the regenerative driving will force the generated power to flow into the battery 9 and the battery 9 will deteriorate rapidly. On the other hand, according to the control device 10 described above, if the charge acceptability of the battery 9 is low, the generator 3 is driven by power running, so that the rattling noise can be suppressed and the deterioration of the battery 9 can be suppressed.

(2) In the control device 10 described above, the inputtable electric power P is calculated on the basis of the charging rate SOC, the soundness SOH, and the temperature T. As a result, the calculation accuracy of the inputtable electric power P can be improved, and the charge acceptability of the battery 9 can be accurately grasped. Therefore, the rattling noise of the gear mechanism can be suppressed more effectively while maintaining the battery performance.
(3) As shown in FIG. 4, the control device 10 sets the torque of the generator 3 to be larger as the engine speed N is lower. By thus setting the generator torque in the low speed range to be large, the gear on the generator 3 side in the gear mechanism 4 can be pressed against the gear on the engine 5 side more strongly, and the rattling noise is less likely to occur. You can

[5. Modification]
The above embodiment is merely an example, and is not intended to exclude various modifications and application of techniques that are not explicitly described in this embodiment. Each configuration of the present embodiment can be variously modified and implemented without departing from the spirit thereof. Also, they can be selected or combined as needed. For example, when calculating the inputtable electric power P of the battery 9, not only the charging rate SOC and the temperature T but also the accelerator opening degree and the vehicle speed may be used together.

Further, although the control device 10 mounted on the hybrid vehicle is illustrated in the above-described embodiment, the control device 10 may be applied to an electric vehicle, an electric cart, or the like. At least a vehicle in which the gear mechanism 4 is interposed between the generator 3 that functions as an electric motor and a generator and the engine 5 achieves the same operational effect by performing the same control as the above-described embodiment. be able to.

1 vehicle 2 motor 3 generator (motor generator)
4 Gear mechanism 5 Engine 6, 7 Inverter 8 Clutch 9 Battery 10 Control device 11 Engine speed sensor 12 Temperature sensor 13 Voltage sensor 14 Current sensor 26 Control program 27 Acquisition unit 28 Calculation unit 29 Control unit
SOC charge rate
SOH soundness
T temperature

Claims (3)

A control device for a hybrid vehicle, comprising: a motor generator functioning as an electric motor and a generator; an engine connected to the motor generator via a gear mechanism; and a battery for exchanging electric power between the motor generator. hand,
An acquisition unit for acquiring information on the charging rate and temperature of the battery,
A calculator that calculates the inputtable electric power of the battery based on the charging rate and the temperature;
In the operating region of the engine in which gear rattle of the gear mechanism may occur, the motor generator is regeneratively driven when the inputtable electric power exceeds a predetermined value, and when the inputtable electric power is a predetermined value or less, A control unit that power-drives the motor generator,
A control device for a hybrid vehicle, comprising: The hybrid vehicle according to claim 1, wherein the calculator calculates the soundness of the battery and calculates the inputtable electric power based on the charging rate, the temperature, and the soundness. Control device. The control device for a hybrid vehicle according to claim 1, wherein the control unit sets the torque of the motor generator to be larger as the rotation speed of the engine is slower.

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