JP7373446B2 - Hybrid vehicle and its control method - Google Patents

Description

The present invention relates to a control technology for a hybrid vehicle that runs using the driving force of at least one of an engine (internal combustion engine) and a motor (electric motor).

A HEV (Hybrid Electrical Vehicle; hereinafter referred to as a hybrid vehicle) is equipped with a motor and an engine, and is driven by the driving force of the motor, the engine, or both depending on the driving state of the vehicle. When the vehicle is being driven by a motor, the engine drives a generator, and the generated power is used to charge the battery or drive the motor. During deceleration, regenerative braking, in which the motor operates as a generator, is used to obtain braking force equivalent to engine braking. The regenerative energy generated during this regenerative braking is used to charge the battery.

In such hybrid vehicles, it is known that noise is generated due to regenerative drive of the motor. Particularly, when the rotational speed of the motor enters the resonance region of noise caused by regeneration, the noise becomes large, and the larger the regenerative torque, the larger the noise becomes. Such a resonant rotational speed of the motor is within the commonly used range and cannot be avoided as a system. Therefore, several techniques have been proposed to suppress noise caused by regeneration. For example, in Patent Document 1, when the rotation speed of one motor is in the resonance region and the other motor is in the non-resonance region, the regenerative torque of the motor on the resonance side is reduced, and the regenerative torque of the motor on the non-resonance side is A control method is disclosed that minimizes regeneration-induced noise by increasing .

Further, as abnormal noises that cannot be avoided in a hybrid vehicle system, there are so-called rattling noises or rattling noises. In hybrid vehicles, the rotational shaft of the engine and the rotational shaft of the motor or generator are connected via a gear mechanism, so the engine flywheel and motor/generator become a large inertial mass, resulting in hysteresis characteristics. Repeated collisions and separations between gears cause abnormal noise. An example of a technique for avoiding such abnormal noise is disclosed in Patent Document 2. According to Patent Document 2, when an engine and a generator are connected via a gear mechanism, rattling noise is avoided by controlling the rotation speed of the generator. More specifically, the rattle noise is avoided by calculating a basic torque command value that makes the torque response of the generator match a predetermined response, and calculating the torque command value of the generator by taking disturbance torque into consideration.

Japanese Patent Application Publication No. 2016-093032 International Publication No. 2017/212581

However, the control method disclosed in Patent Document 2 only controls the torque of the generator so as not to use the generation torque region where rattling noise occurs, and the generator is It does not take into account that the amount of electricity generated will decrease. Hereinafter, with reference to FIG. 1, problems with the control method of Patent Document 2 will be briefly explained.

In FIG. 1, when the accelerator pedal is fully closed (a), the motor performs regeneration, and a torque instruction is given to the motor to provide a regenerative braking force equivalent to engine braking (c). Further, although the generator continues to generate electricity using the engine, the generated torque value 10 decreases in accordance with the regenerated power of the motor. However, the power generation torque value 10 is set to a level that does not fall within the rattle sound generation region R, as shown in FIG. 1(e). As a result, the regenerative power of the motor and the amount of power generated by the generator are adjusted so as to maintain the target power of the battery (target bat end power), and the generated torque is controlled so as not to fall into the rattle noise generation region R. Ru.

However, when the brake operation 11 is performed, regenerative power 11a of the motor is generated. As mentioned above, the amount of power generated by the generator is adjusted to maintain the target Bat end power of the battery, so when the regenerated power 11a is generated, the battery is charged with the regenerated power 11a while maintaining the target Bat end power. In order to do so, it is necessary to reduce the amount of power generated by the generator by an amount corresponding to the generation amount 11c. For this reason, when the line power resulting from the brake operation is large, the generated torque is reduced by the regenerated power equivalent 11c, as shown in FIG. 1(e), and as a result, falls into the rattle noise generation region R.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a hybrid vehicle and a control method thereof that can maintain generated torque even when the regenerative power of a driving motor increases.

According to a first aspect of the present invention, there is provided a hybrid vehicle that runs using the driving force of at least one of an engine (109) and a motor (107), and includes a chargeable/dischargeable battery (101) and the engine (109). A generator (111) generates electricity through rotation, and the battery (101) is powered by the generated power of the generator (111) and/or the regenerated power (11a) of the motor (107) according to the target battery terminal power of the battery (101). a control unit (125) that controls the engine (109) and the generator (111) so that the engine (109) and the generator (111) are charged; 11a) increases, the target battery terminal power is increased in accordance with the increase in the regenerated power (11a), and the generated torque (20a) of the generator (111) is maintained at a value larger than a predetermined range.
According to the second aspect of the present invention, a generator ( 111), wherein the regenerative power (11a) of the motor (107) increased due to the use of the brake is calculated, and the target battery terminal power is determined according to the increase in the regenerative power (11a). is increased, and the engine ( 109) and the generator (111), the power generation torque (20a) of the generator (111) is maintained at a value larger than a predetermined range.
According to the third embodiment of the present invention, a generator ( 111) A program for causing a processor to function as a control device for a hybrid vehicle having a function of calculating regenerative power (11a) of the motor (107) increased due to use of the brake, and an increase in the regenerative power (11a) The battery (101) has a function of increasing the target battery terminal power according to the number of minutes, and the generated power of the generator (111) and/or the regenerated power (11a) of the motor (107) according to the increased target battery terminal power. ), the processor maintains the power generation torque (20a) of the generator (111) at a value larger than a predetermined range by controlling the engine (109) and the generator (111) so that the engine (109) and the generator (111) are charged. to be realized.
According to this, even if the regenerated power due to brake use increases, by increasing the target power value of the battery according to the increase, the generated torque can be maintained without changing the amount of power generated by the generator. , it is possible to avoid a situation where the power generation torque drops to a predetermined range.
The control unit (125) includes a regenerative power calculation means (204) that calculates the regenerative power (11a) of the motor (107) that may be generated by the brake operation and/or accelerator pedal operation, and A target battery power calculation means (205) increases the regenerative power according to the regenerated power (11a), and calculates the engine (109) based on at least the increased target battery power, the actual battery power, and the required driving force. ), an engine output calculation means (207) for calculating the required torque of the engine. This allows the generated torque to be maintained even if the regenerative power of the motor increases due to brake or accelerator operations.
The predetermined range of the power generation torque (20a) is determined by the range of the generator (111) in a system in which the engine (109) and the motor (107) or the generator (111) are coupled via a gear mechanism (119). The gear mechanism (119) may generate abnormal noise when the power generation torque (20a) decreases. Thereby, even if the regenerated power due to the use of the brake increases, the occurrence of abnormal noise in the gear mechanism can be avoided.

As described above, according to the present invention, the generated torque can be maintained even if the regenerated power of the driving motor increases, and for example, generation of rattling noise in the gear mechanism can be effectively avoided.

FIG. 3 is a waveform chart showing changes in accelerator pedal opening, brake operation, motor torque, target battery terminal power, generated torque, and engine torque to explain the occurrence of rattling noise when the control according to the background art is applied. 1 is a block diagram schematically showing an example of an internal configuration of a hybrid vehicle according to an embodiment of the present invention. FIG. 1 is a schematic block diagram showing an example of a control device for a hybrid vehicle according to the present embodiment. FIG. 2 is a waveform diagram showing changes in accelerator opening, brake operation, motor torque, target battery terminal power, generated torque, and engine torque in an example of the control method according to the present embodiment.

1. Summary of Embodiments According to embodiments of the present invention, even if the regenerated power due to brake use increases, the target power value of the battery is increased in accordance with the increase, thereby maintaining the generated torque, Avoid using .

Embodiments of the present invention will be described below using a series/parallel type hybrid vehicle as an example. The series/parallel method is a method in which the drive power transmission system is switched to either the series method or the parallel method.The series method uses the driving force of the motor to drive the vehicle and uses the engine for power generation, and the parallel method This is a system in which the vehicle runs using the driving power of either the motor or the engine, or both. The present invention is not limited to the series/parallel system, but is also applicable to the series system and the parallel system.

2. Overall Configuration As illustrated in FIG. 2, a series/parallel type hybrid vehicle (hereinafter simply referred to as "vehicle") includes a battery (BATT) 101, a converter (CONV) 103, and a first inverter (INV1) 105. , an electric motor (MOT) 107, an engine (ENG) 109, a generator (GEN) 111, a second inverter (INV2) 113, a lock-up clutch (hereinafter simply referred to as "clutch") 115, and a hydraulic circuit. 117, a gear box (hereinafter simply referred to as "gear") 119, a vehicle speed sensor 121, a rotation speed (NE) sensor 123, various electronic control units (ECU), and a management ECU (MG-ECU) 125. , is provided. Here, as various ECUs, a generator ECU (GEN-ECU), an engine ECU (ENG-ECU), a motor ECU (MOT-ECU), a brake ECU (BRK-ECU), etc. are illustrated.

The control function according to this embodiment is implemented in the management ECU 125. Note that in FIG. 2, solid line arrows indicate control signals, and broken line arrows indicate detection signals.

The battery 101 has a plurality of storage cells connected in series and supplies a high voltage of, for example, 100 to 200V. The power storage cell is, for example, a lithium ion battery or a nickel metal hydride battery. Converter 103 steps up or steps down the DC output voltage of battery 101 while keeping it as DC. The first inverter 105 converts DC voltage into AC voltage and supplies three-phase current to the motor 107. Further, the first inverter 105 converts the AC voltage input during the regenerative operation of the motor 107 into a DC voltage, and charges the battery 101 with the DC voltage. The state of the battery 101 can be measured from the terminal voltage, current, and temperature of the battery 101. In this embodiment, as will be described later, the management ECU 125 inputs the actual BATT terminal power P _BATT (current charging/discharging power actual value) of the battery 101 and sets the charging state of the battery 101 to the target BATT terminal power P _BATT ). Execute power generation and charging control to match.

Motor 107 generates power for driving the vehicle. Torque generated by motor 107 is transmitted to drive shaft 127 via gear 119. Note that the rotor of the motor 107 is directly connected to the gear 119. Further, the motor 107 operates as a generator during regenerative braking, and the electric power generated by the motor 107 is charged to the battery 101. Control of the motor 107 is executed by the motor ECU according to a motor torque command from the management ECU 125.

Engine 109 is used only to drive generator 111 when clutch 115 is released and the vehicle runs in series. However, when clutch 115 is engaged, the output of engine 109 is transmitted to drive shaft 127 via generator 111, clutch 115, and gear 119 as mechanical energy for driving the vehicle.

Generator 111 is driven by the power of engine 109 and generates electric power. The electric power generated by the generator 111 is charged into the battery 101 or supplied to the motor 107 via the second inverter 113 and the first inverter 105. The second inverter 113 converts the AC voltage generated by the generator 111 into DC voltage. The electric power converted by the second inverter 113 is charged into the battery 101 or supplied to the motor 107 via the first inverter 105.

Clutch 115 connects/disconnects a drive power transmission path from engine 109 to drive wheels 129 based on instructions from management ECU 125. Hydraulic circuit 117 supplies a predetermined operating pressure to clutch 115 via hydraulic oil. Note that the hydraulic circuit 117 sends a signal indicating the temperature To of the hydraulic oil to the management ECU 125 via the motor ECU.

The gear 119 is, for example, a one-stage fixed gear equivalent to a fifth speed. Therefore, the gear 119 converts the driving force from the motor 107 into rotation speed and torque at a specific gear ratio, and transmits the rotation speed and torque to the drive shaft 127. Vehicle speed sensor 121 detects the traveling speed of the vehicle (vehicle speed VP). A signal indicating the vehicle speed VP detected by the vehicle speed sensor 121 is sent to the management ECU 125. Rotation speed sensor 123 detects rotation speed NE of engine 109. A signal indicating the rotation speed NE detected by the rotation speed sensor 123 is sent to the management ECU 125.

The management ECU 125 calculates the rotation speed of the motor 107 based on the vehicle speed VP, connects and disconnects the clutch 115 using the hydraulic circuit 117, switches the driving mode, and controls the motor 107, engine 109, and generator 111, etc. to various ECUs. Execute by command. The management ECU 125 is composed of a rewritable ROM or the like, and programs and data can be written/rewritten thereto. Further, by executing a program stored in the storage means on the processor, it is also possible to realize the control function of the management ECU 125 described below.

3. Control Device As illustrated in FIG. 3, the control device according to this embodiment is installed in the management ECU 125 in FIG. 2. The management ECU 12 includes a regenerative torque request calculation section 201, a required driving force calculation section 202, a motor instruction torque calculation section 203, a regenerative power calculation section 204, a basic target battery terminal power calculation section 205, an adder 206, and a required engine output calculation section 207. It has a functional configuration consisting of: The characteristic configuration of this embodiment is that a regenerated power calculation section 204 is provided to calculate the final target battery terminal power in consideration of the regenerated power, thereby avoiding fluctuations in the generator torque.

The regenerative torque request calculating section 201 calculates the regenerative torque request according to the brake operation, and in this embodiment, the regenerative torque request calculating section 201 is provided in the brake ECU. The required driving force calculation unit 202 calculates the vehicle required driving force from the vehicle speed VP and the access opening degree AP. The motor instruction torque calculation unit 203 calculates the motor torque using the regenerative torque request input from the regeneration torque request calculation unit 201, the vehicle required driving force input from the required driving force calculation unit 202, and the motor rotation speed, An instruction for the calculated motor torque value is output to the motor ECU.

The regenerated power calculation unit 204 inputs the motor torque value calculated by the motor instruction torque calculation unit 203, the motor rotation speed, and the ECVT efficiency, and calculates the regenerated power P _regene that increases during motor regeneration. Further, the basic target battery power calculation unit 205 calculates the basic target battery power P _T1 using the vehicle speed VP and the engine rotation speed NE. Adder 206 adds regenerated power P _regene to basic target battery power P _T1 to calculate final target battery power P _T2 and outputs it to required engine output calculation section 207 . That is, the final target battery power P _T2 , which is the basic target battery power P _T1 increased by the regenerated power P _regene , is output to the required engine output calculation unit 207.

The required engine output calculation unit 207 calculates the final target battery terminal power P _T2 , the vehicle required driving force calculated by the required driving force calculation unit 202, the current actual BATT terminal power P _BATT of the battery 101, and other data (compensation). The required engine output is calculated by inputting the machine's power consumption, motor efficiency, and generator efficiency. Here, the required engine output calculation unit 207 instructs the engine ECU and the generator ECU of the target engine rotation speed _NET , engine request torque, and generator torque as the required engine output.

More specifically, the required engine output calculation unit 207 controls the generator 111 and the engine 109 so that the current actual BATT terminal power P _BATT of the battery 101 becomes the final target battery terminal power P _T2 . Since the battery terminal power P _T2 has a value as large as the regenerated power P _regene of the engine 109, the battery 101 can be charged, and there is no need to reduce the generated torque of the generator 111. In this way, by increasing the target battery terminal power P _T2 during brake regenerative power generation, the power generation torque of the generator 111 can be maintained at the basic level, and it is possible to avoid entering the rattle noise generation region. This will be explained in detail below.

4. Control Operation In FIG. 4, it is assumed that the accelerator pedal is fully closed at time t1 (a). At this time, the torque of the motor 107 is regenerated from driving to the equivalent of engine braking, and the battery 101 is charged by the regenerated power. For this reason, the power generation torque of the generator 111 decreases as shown in the basic level value 10, but is maintained at a value greater than the rattle sound generation region R.

When the access is fully closed and the brake operation 11 is performed from time t2 to t3 and regenerative torque is requested, the management ECU 125 increases the motor torque and regenerative braking according to the vehicle speed VP and accelerator opening AP at that time. (Reference number 11a in Figure 4). When the motor torque increases toward the regenerative side, the regenerated power calculation unit 204 calculates the regenerated power P _regene corresponding to the increase, and the regenerated power P _regene is added to the basic target battery terminal power P _T1 , and the final target battery terminal power P _T2 is is calculated (reference number 20).

In this way, the management ECU 125 can charge the battery with the regenerated power by increasing the target battery terminal power _PT by the amount of power generated during brake regeneration, and the management ECU 125 can charge the battery with the regenerated power, and the engine 109 and the generator 111 can be activated as shown in reference numbers 20a and 20b. can be controlled. As a result, the generated torque of the generator 111 is maintained at the basic level value 10, so even if the brake is operated when the accelerator AP is fully closed, the generated torque does not fall into the rattle noise generation region R (reference number 20a). That is, the management ECU 125 controls the engine 109 and the generator 111 as shown in FIGS. 4(e) and 4(f) by increasing the target battery terminal power _PT by the amount of power generated during brake regeneration to generate rattling noise. can be avoided.

5. Effects As explained above, according to the embodiment of the present invention, even if the regenerated power 11a due to brake use increases, the generated torque 20a can be increased by increasing the target power value _PT of the battery according to the increase. The basic level can be maintained at 10, and use in the rattle sound generation region R can be avoided.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the claims and the technical idea described in the specification and drawings. is possible.

101 Battery 103 Converter 105 First inverter 107 Motor 109 Engine 111 Generator 113 Second inverter 115 Clutch 117 Hydraulic circuit 119 Gear box 121 Vehicle speed sensor 123 Number of revolutions (NE) sensor 125 Management ECU (MG-ECU)
201 Regenerative torque request calculation section 202 Requested driving force calculation section 203 Motor instruction torque calculation section 204 Regenerative power calculation section 205 Basic target battery terminal power calculation section 206 Adder 207 Required engine output calculation section

Claims (7)

A hybrid vehicle that runs using the driving force of at least one of an engine and a motor,
A chargeable and dischargeable battery,
a generator that generates electricity by rotation of the engine;
a control unit that controls the engine and the generator so that the battery is charged by the generated power of the generator and/or the regenerated power of the motor according to a target battery terminal power of the battery;
Equipped with
When the regenerative power of the motor increases due to brake use, the control unit increases the target battery terminal power in accordance with the increase in the regenerative power, and maintains the generated torque of the generator at a value larger than a predetermined range. A hybrid vehicle characterized by: The control unit includes:
Regenerative power calculation means for calculating the regenerative power of the motor that may be generated by the use of the brake and/or the operation of the accelerator pedal;
Target battery power calculation means for increasing the target battery power in accordance with the regenerated power;
engine output calculation means for calculating the required torque of the engine based on at least the increased target battery terminal power, the actual battery terminal power, and the required driving force;
The hybrid vehicle according to claim 1, characterized in that it has the following. The predetermined range of the power generation torque is a range in which abnormal noise is generated in the gear mechanism when the power generation torque of the generator decreases in a system in which the engine and the motor or the generator are coupled via a gear mechanism. The hybrid vehicle according to claim 1 or 2, characterized in that: A method for controlling a hybrid vehicle that is driven by the driving force of at least one of an engine and a motor and has a chargeable and dischargeable battery and a generator that generates electricity by the rotation of the engine, the method comprising:
Calculate the regenerative power of the motor that increased due to the use of the brake,
increasing the target battery terminal power according to the increase in the regenerated power;
By controlling the engine and the generator so that the battery is charged by the generated power of the generator and/or the regenerated power of the motor according to the increased target battery terminal power, the generated torque of the generator is controlled within a predetermined range. A hybrid vehicle control method characterized by maintaining a larger value. Regenerative power calculation means calculates the regenerative power of the motor that may be generated by the use of the brake and/or the operation of the accelerator pedal,
Target battery end power calculation means increases the target battery end power according to the regenerated power,
The hybrid according to claim 4, wherein the engine output calculation means calculates the required torque of the engine based on at least the increased target battery terminal power, the actual battery terminal power, and the required driving force. How to control the vehicle. The predetermined range of the power generation torque is a range in which abnormal noise is generated in the gear mechanism when the power generation torque of the generator decreases in a system in which the engine and the motor or the generator are coupled via a gear mechanism. The method for controlling a hybrid vehicle according to claim 4 or 5, characterized in that: A program that causes a processor to function as a control device for a hybrid vehicle that runs using the driving force of at least one of an engine and a motor, and has a chargeable and dischargeable battery and a generator that generates electricity by the rotation of the engine, the program comprising:
a function that calculates the regenerative power of the motor increased due to the use of the brake;
a function of increasing the target battery terminal power according to the increase in the regenerated power;
By controlling the engine and the generator so that the battery is charged by the generated power of the generator and/or the regenerated power of the motor according to the increased target battery terminal power, the generated torque of the generator is controlled within a predetermined range. and the ability to maintain a larger value.
A program characterized in that the program implements the following in the processor.