JP2004242450A - Controller for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem: when fuel injection is started in engine fuel cut state during regenerative braking operation, the power consumption of a generator motor 2 is temporarily and significantly increased, and this can lead to power loss and have harmful effect on a power storage device 6. <P>SOLUTION: In regenerative braking operation, power is generated by a driving motor 3, using drive wheels 5 as a driving source, and an engine 1 is driven by the generator motor 2 so that the above generated power is consumed in just proportion. If fuel injection is started in fuel cut state during such regenerative braking operation, the operation mode of the generator motor 2 is changed from number of revolutions control mode toward a target number of revolutions to torque control toward a target torque. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for a hybrid vehicle, and more particularly, to control at the time of vehicle deceleration and braking.
[0002]
[Prior art]
2. Description of the Related Art In recent years, hybrid vehicles that achieve improved fuel efficiency and reduced exhaust gas have attracted attention. For example, Patent Document 1 discloses that during normal driving traveling, a generator motor generates electric power by an engine, stores the electric power in a battery (power storage device), and consumes electric power from the generator motor and the battery to drive the driving motor in power running operation. A so-called series-type hybrid vehicle that drives an axle by driving the vehicle is disclosed. At the time of vehicle deceleration / braking with fuel cut of the engine, the drive motor is generated by the power from the drive wheels so that the vehicle braking force can be obtained, and for example, when the battery is fully charged, the generated power is obtained. The engine is driven and motored by the generator motor so that it can be consumed without excess or deficiency.If power cannot be consumed by the motoring, an auxiliary brake that mechanically brakes the wheels using frictional force is used. It is described as operating. In such a series-type hybrid vehicle, generally, the engine is torque-controlled toward a target torque, and the number of revolutions of the generator motor, which has higher responsiveness and accuracy than the engine, is controlled toward the target speed. .
[0003]
[Patent Document 1]
JP 2001-238303 A
[0004]
[Problems to be solved by the invention]
When the fuel injection is started (restarted) during the deceleration operation accompanied by the fuel cut of the engine as described above, the target rotation speed of the power generation motor sharply increases due to the engine torque generated by the ignition and combustion of the fuel. However, there is a possibility that the torque (powering torque) of the generator motor may temporarily increase significantly so as to follow the rapid increase in the target rotation speed. In this case, the power consumption of the power generation motor temporarily exceeds the power generated by the drive motor temporarily, and the power of the battery is temporarily greatly consumed, resulting in power loss and overdischarge of the battery, May have an adverse effect on the durability of the steel. The present invention has been made in view of such a problem.
[0005]
[Means for Solving the Problems]
A power generation motor that mainly generates power using the engine as a drive source, a drive motor that mainly drives driving wheels, and a power storage device that is electrically connected to both the power generation motor and the drive motor and temporarily stores power are provided. The target driving force is calculated according to the driver's request, and the driving motor is controlled according to the target driving force. While calculating the target power generation amount of the power generation motor according to the target driving force, the actual rotation speed of the engine or the power generation motor is detected, and the target power generation torque of the power generation motor is calculated according to the target power generation amount and the actual rotation speed. Calculate. Further, a target rotation speed of the engine or the generator motor is calculated according to the target power generation amount. The generator motor can be controlled by switching between a rotation speed control mode for the target rotation speed and a torque control mode for the target generation torque. When starting the fuel injection from an operation state involving a fuel cut of the engine, the generator motor is switched from the rotation speed control to the torque control.
[0006]
【The invention's effect】
According to the present invention, the power generation motor is switched from the rotation speed control to the torque control when starting the fuel injection from an operation state involving a fuel cut of the engine, so that the power consumption of the power generation motor immediately after the start of the fuel injection is reduced. Is optimized in accordance with the regenerative power of the drive motor, and the power consumption of the generator motor does not temporarily exceed the regenerative power of the drive motor. Therefore, careless power loss can be eliminated, and the load on the power storage device can be reduced.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 schematically shows an embodiment of a series-type hybrid vehicle to which a control device according to the present invention is applied. The power train of the vehicle includes an engine 1, a generator motor (first motor generator) 2, which is directly connected to the engine 1 so as to be capable of mechanical and power transmission, and is mainly driven by the engine 1 to generate electric power. A drive motor (second motor generator) that is electrically connected to the drive wheel 2 and is capable of transmitting electric power and mechanical power, and is connected to the drive wheel 5 so as to transmit power mechanically and rotationally drives the axle of the drive wheel 5 mainly by consuming power. Machine 3). The engine 1 is a known gasoline engine, diesel engine, or the like, and generates engine torque by burning fuel.
[0008]
The generator motor 2 and the drive motor 3 are three-phase AC type motor generators (motor generators) that can perform both power running operation and regenerative operation using an inverter. While the vehicle is running, the generator motor 2 generates power using the engine 1 as a drive source, and the drive motor 3 consumes power to drive the drive wheels 5. On the other hand, when the vehicle is decelerated or braked with a fuel cut, the driving motor 3 generates power using the driving wheels 5 as a driving source, and the power generation motor 2 consumes the power to perform power running operation, contrary to the above-described driving traveling. And the engine 1 is rotationally driven and motored against the engine friction.
[0009]
The power generation motor 2 and the drive motor 3 are electrically connected to a power storage device 6 such as a battery or a capacitor that stores power. The power storage device 6 stores power generated by the power generation motor 2 and the drive motor 3 and supplies power for the power generation operation to the power generation motor 2 and the drive motor 3. It should be noted that, in addition to the power storage device 6, an auxiliary power storage device of a weak current system for supplying power to a controller, various sensors, and annotations described later may be provided, or the power storage device 6 may be provided as a controller or an annotation. The function of supplying power may also be used. A final gear 4 as a final reduction gear is provided in a power transmission path between the drive motor 3 and the drive wheels 5. The power train may be provided with a well-known torque converter or transmission.
[0010]
The control system of the vehicle includes a plurality of controllers as digital computers, that is, an engine controller 7 for controlling the engine 1, a generator motor controller 8 for controlling the generator motor 2, a drive motor controller 11 for controlling the drive motor 3, a power storage device. The power storage device controller 10 monitors the power storage device 6 and an integrated controller 9 connected to these controllers so as to be capable of bidirectional communication.
[0011]
The integrated controller 9 is connected to various sensors for detecting a vehicle driving state, such as an accelerator opening sensor 14 for detecting a depression position and an opening (APS) of an accelerator pedal 12 and a vehicle speed sensor 13 for detecting a vehicle speed. I have. The integrated controller 9 outputs control signals to the controllers 7, 8, and 11 and various actuators based on the sensors and signals indicating the state of power storage from the power storage device controller 10, and controls the operation of the vehicle. To control.
[0012]
The engine controller 7 controls the engine 1 toward a target torque. Specifically, based on an engine torque command value as a target torque output from the integrated controller 9 and a fuel cut signal, the throttle opening, fuel injection amount, fuel injection timing, ignition timing, and the like of the engine 1 are controlled. The drive motor controller 11 performs vector control of the drive motor 3 based on the motor torque command value transmitted from the integrated controller 9. Based on the voltage and current of power storage device 6 detected by a voltage sensor / current sensor (not shown), power storage device controller 10 stores a state of charge (SOC) of power storage device 6 and input / output available power. Is calculated and transmitted to the integrated controller 9.
[0013]
The generator motor controller 8 can operate and control the generator motor 2 by switching between two control modes, that is, a rotation speed (rotation speed) control mode and a torque control mode.
[0014]
In the rotation speed control mode, the power generation motor 2 is controlled toward a rotation speed command value that is a target rotation speed (rotation speed control means). That is, the actual rotation speed (actual rotation speed) of the engine 1 and the generator motor 2 is feedback-controlled toward the rotation speed command value transmitted from the integrated controller 9 to the generator motor controller 8. Specifically, the vector control of the generator motor 2 is performed according to the deviation between the rotation speed command value and the actual rotation speed so that the actual rotation speeds of the engine 1 and the generator motor 2 become equal to the rotation speed command value. The actual rotation speed may be detected by a known crank angle sensor, or a detection value of the motor rotation speed of the generator motor 2 may be used (actual rotation speed detection means).
[0015]
In the torque control mode, the generator motor 2 is controlled toward a torque command value that is a target torque of the generator motor 2 (torque control means). Specifically, the vector control of the generator motor 2 is performed based on the torque command value output from the integrated controller 9 to the generator motor controller 8.
[0016]
5 and 6 are time charts showing a situation in which fuel injection is started from a vehicle deceleration state accompanied by a fuel cut of the engine 1. FIG. In the figure, the vertical axis of the uppermost row (a) is the target driving force of the driving wheel 5, and is dependent on the accelerator opening from the accelerator opening sensor 14 and the vehicle speed from the vehicle speed sensor 13 according to the driver's request. Required. During the deceleration / regenerative operation, the target driving force has a negative value, and the drive motor controller 11 performs power generation according to the target driving force to obtain regenerative power. The vertical axis of the second stage (b) from the top is the engine speed. In this embodiment, since the engine 1 and the motor 2 are directly connected, the engine speed is equal to the speed of the motor 2. The vertical axis of the third stage (c) from the top is the torque of the generator motor 2, and here the power running side is a positive value. In other words, when the vertical axis of (c) is viewed as a power generation torque with the power generation side being positive, the upper side of the vertical axis has a negative value (powering side) and the lower side has a positive value (regeneration side). The vertical axis at the bottom (d) represents the power consumption of the power generation motor 2, which is a positive value when the power generation motor 2 performs the power running operation and a negative value when the power generation motor 2 performs the regenerative operation.
[0017]
FIGS. 5 and 6 show a situation where the target driving force gradually changes from a negative value (regeneration-side value) to a positive value (power-running side value). Neither the brake pedal nor the brake pedal is depressed, which corresponds to a situation where the vehicle gradually decelerates. Further, when all of the regenerative power from the drive motor is consumed by the engine and the generator motor so as to reduce the load on the power storage device 6 and the brake device that mechanically brakes the wheels, that is, there is no battery input / output, and It is assumed that no braking force is applied by the braking device. FIG. 5 shows the characteristics according to the present embodiment, that is, the characteristics when the power generation motor 2 is switched from the rotation speed control mode to the torque control mode when the fuel injection is started from the regenerative braking operation state accompanied by the fuel cut. ing. On the other hand, FIG. 6 shows the characteristics according to the comparative example, that is, the characteristics in the case where the generator motor 2 is continuously operated in the rotation speed control mode regardless of the presence or absence of the fuel injection.
[0018]
First, a technical problem in the comparative example will be described with reference to FIGS. When the vehicle is in regenerative braking with a fuel cut and the battery has a sufficient amount of stored power and cannot (or does not need to) receive regenerative power with this battery, the engine during the fuel cut is generated. By motoring with a motor and power running with the engine friction as a load, the power regenerated by the drive motor is consumed by the generator motor without excess or shortage, and input / output to the battery and use of a mechanical brake device are avoided / suppressed. Thus, a desired braking force can be obtained. To change the power consumption, the target engine speed may be changed. Since the engine speed increases as the power consumption increases, the target engine speed may be increased when the power consumption is increased, and the target engine speed may be decreased when the power consumption is reduced.
[0019]
Since the regenerative electric power by the drive motor is a value according to the driver's request, it is a continuous value from 0 kW. On the other hand, it is very difficult to set the power consumption of the generator motor to a continuous value from 0 kW. Specifically, as shown in FIG. 7, in a situation where the engine speed is lower than a predetermined lower limit speed Nmin, it is very difficult to stably motor the engine 1 with the generator motor 2. Therefore, when consuming extremely small electric power that is lower than the lower limit rotation speed Nmin, a minimum amount of fuel is injected into the engine, and the engine rotation speed is intentionally increased by the generated engine torque. Therefore, when the regenerative electric power changes before and after the electric power that can be consumed at the lower limit rotational speed Nmin, the engine repeats the fuel injection and the fuel cut, and the target engine rotational speed changes greatly accordingly.
[0020]
A solid line L1 in FIG. 8 indicates a transition of the operating point of the power generation motor when fuel is injected from the fuel cut state and the power consumption of the power generation motor is gradually reduced. If the regenerative power is higher than the lower limit power consumption at the lower limit rotational speed Nmin, the target rotational speed is reduced in accordance with a decrease in the regenerative power of the drive motor in the engine fuel cut state. When the regenerative power becomes lower than the lower limit power consumption, the engine speed cannot be reduced any more in the fuel cut state, so fuel injection of the engine is started, and the engine speed is made higher than the lower limit speed by the engine torque. Enables setting of extremely small power consumption. As the regenerative power further decreases, the target engine speed is reduced along the line of the minimum torque during fuel injection.
[0021]
The generator motor directly connected to the engine is generally operated in a rotation speed control mode. That is, it is general that the torque is controlled by the engine and the number of revolutions is controlled by the generator motor. The reason for this is that the torque control accuracy differs greatly between the engine and the motor.By controlling the rotation speed with a high-response and high-precision motor, the control accuracy of the operating point related to fuel efficiency is improved, and the operating point fluctuation is improved. The adverse effect on drivability due to the vehicle can be minimized. Specifically, as in the comparative example shown in FIG. 6, the generator motor is operated in the rotation speed control mode regardless of the presence or absence of the fuel cut, and is controlled toward the target rotation speed.
[0022]
However, when the generator motor is continuously operated toward the target rotation speed regardless of the presence or absence of the fuel cut, the target rotation speed sharply changes when fuel injection is started from the fuel cut state. That is, the target rotation speed after the fuel injection includes the increase in the rotation speed due to the engine torque, so that the target rotation speed sharply increases at the start of the fuel injection. The generator motor with good responsiveness tries to follow this sudden change in the target rotation speed as fast as possible. That is, the generator motor outputs the maximum torque in an attempt to increase the actual rotation speed in accordance with the target rotation speed that has rapidly increased. For this reason, the torque (powering side) of the power generation motor temporarily increases greatly, and accordingly, the power consumption of the power generation motor 2 sharply increases as shown by an arrow Y1 in FIG. It greatly exceeds the power. In other words, in addition to the regenerative power, the power consumed by the engine and the generator motor includes the inertia component for increasing the actual rotation speed, which results in the consumption of power exceeding the regenerative power. Become. This extra power is consumed from the power storage device 6 to cause power loss, and may cause over-discharge and reduced durability of the power storage device.
[0023]
On the other hand, in the present embodiment, as shown in FIG. 5, during the regenerative braking operation period T1 in which the fuel is cut and the power of the drive motor 3 is generated, the rotation speed control having good responsiveness and controllability is performed similarly to the comparative example. When the fuel injection is started from the regenerative braking operation period T1 while the generator motor 2 is operated and controlled according to the mode, when the fuel injection is started from the start of the fuel injection to a predetermined fuel injection start period T2, the torque control mode for the target torque is set. Drives and controls the generator motor 2. Accordingly, there is no sharp rise in the torque on the powering side of the power generation motor 2, and the regenerative power of the drive motor 3 is stably consumed by the power generation motor 2 without excess or deficiency. As a result, temporary large discharge of the power storage device 6 can be avoided, the energy efficiency is improved, and there is no possibility that the power storage device 6 will be overdischarged or have reduced durability.
[0024]
However, when the mode is switched to the torque control mode during the fuel injection start period T2 as in the present embodiment, the followability of the actual speed to the target speed is reduced and the rise of the actual speed is delayed as compared with the comparative example. . However, in a situation where the target driving force is a negative value on the regenerative / power generation side (a situation where the driver does not depress the accelerator pedal), it is not necessary to increase the engine speed in a hurry. It does not adversely affect driving performance.
[0025]
Hereinafter, the specific configuration and operation and effect of the present embodiment will be described in detail. FIG. 2 is a control block diagram showing the contents of the control processing stored and executed by the integrated controller 9 of FIG. The processing shown in this control block diagram is repeatedly calculated and executed at regular intervals (for example, every 10 msec).
[0026]
The target axle driving torque calculating section 15 sets a predetermined axle driving force based on the opening (APS) signal of the accelerator pedal 12 detected by the accelerator opening sensor 14 and the vehicle speed detected by the vehicle speed sensor 13. The target axle driving torque Tsd is determined with reference to the torque map.
[0027]
The target drive motor torque calculation unit 16 divides the target axle drive torque Tsd by the reduction ratio Gf of the final gear 4 to obtain a drive motor torque command value Tsm that is the target torque of the drive motor 3. The drive motor torque command value Tsm is sent to the drive motor controller 11, and the drive motor controller 11 performs vector control of the drive motor 3 based on the value Tsm.
[0028]
The target driving force calculation unit (target driving force calculation means) 17 multiplies the target axle driving torque Tsd by the axle rotation speed obtained from the vehicle speed of the vehicle speed sensor 13 to obtain the target driving force (power) Psd of the drive motor 3.
[0029]
The target generated power calculation unit (target power generation amount calculation means) 18 estimates the loss generated in the drive motor 3 and adds the loss to the target drive force Psd (efficiency correction) to reduce the power consumption of the drive motor 3. Ask. In order to reduce the input / output to the power storage device 6, the control is basically performed so that the power consumed by the drive motor 3 is generated by the power generation motor 2 without excess or shortage. The power generation amount Pgen is equal to the power consumption of the drive motor calculated by the target generated power calculation unit 18. When performing input and output to and from the power storage device 6, the target generated power Pgen of the power generation motor 2 is obtained by adding this input and output to the power consumption of the drive motor 3. When regeneration is performed by the drive motor 3 (that is, when the target axle drive torque Tsd is a negative value), the target generated power Pgen becomes a negative value, and the power generation motor 2 performs power running operation. The method of estimating the loss of the drive motor is to prepare a drive motor loss map by measuring the loss according to the torque and rotation speed of the drive motor 3 in advance, and to determine the drive motor torque command value Tsm and the actual drive motor torque. A method of obtaining the driving motor loss map with reference to the rotation speed based on the rotation speed may be considered.
[0030]
The determination unit 19 generates a fuel cut signal fcut indicating the presence or absence of a fuel cut, and a control switching signal fchg indicating an operation mode of the generator motor 2, that is, switching between a rotation speed control mode and a torque control mode. The fuel cut signal fcut is sent to the engine controller 7 together with an engine torque command value Ts described later, and the throttle opening and the fuel injection amount of the engine 1 are controlled based on the both. When the fuel cut signal fcut is "1", the fuel cut is executed, and when it is "0", the fuel cut is not executed, and the fuel is injected and supplied. The control switching signal fchg is sent to the power generation motor controller 8 together with a power generation motor rotation speed command value Ns and a power generation motor torque command value Tg described later. When the control switching signal fchg is “0”, the rotation speed of the power generation motor 2 is controlled. Specifically, the vector control of the power generation motor 2 is performed so that the actual rotation speed of the power generation motor or the engine becomes the power generation motor rotation speed command value Ns. On the other hand, when the control switching signal fchg is 1, the torque of the power generation motor 2 is controlled. More specifically, the generated motor torque command value calculating means 25, which will be described later, generates the generated motor torque command based on the target generated power Pgen (or the torque command value Tsm of the drive motor) and the actual rotation speeds of the engine 1 and the generated motor 2. The value Tg is calculated, and the vector control of the generator motor 2 is performed according to the torque command value.
[0031]
FIG. 3 shows a flow of a setting process of the fuel cut signal fcut in the determination unit 19. In S (step) 1, it is determined whether the target axle driving torque Tsd is a negative value, that is, a value on the power generation / regeneration side. At S2, the regenerative power of the drive motor is the lower limit power consumption which is the minimum power consumption that can be stably consumed by the generator motor during the fuel cut (the engine speed is lower than the lower limit Nmin in the fuel cut state (see FIG. 5 to FIG. 5). 8)). If both S1 and S2 are affirmative, the process proceeds to S3, where the fuel cut signal fccut is set to "1" (fuel cut). If one of S1 and S2 is denied, the process proceeds to S4, and the fuel cut signal fcut is set to "0" (fuel injection). Therefore, when the drive motor 3 is performing regenerative operation at the time of deceleration and the regenerative power of the drive motor 3 exceeds the lower limit power consumption of the generator motor 2, both S1 and S2 are affirmed and the fuel cut is performed. Be executed. When the drive motor 3 is performing the power running operation, S1 is negative and the fuel is injected. Even if the drive motor 3 is performing regenerative operation, if the regenerative power of the drive motor 3 is lower than the lower limit power consumption of the generator motor 2, S1 is affirmative, S2 is negative, and no fuel cut is performed. Of fuel is injected.
[0032]
FIG. 4 shows a flow of a setting process of the control switching signal fchg in the determination unit 19. In S11, it is determined whether the target axle drive torque Tsd is a negative value, that is, a value on the power generation / regeneration side. In S12, it is determined whether or not the fuel cut signal fcut is “0” (fuel injection). In S13, it is determined whether it is the fuel injection start period T2 (see FIG. 5). If all of S11 to S13 are affirmed, the process proceeds to S14, where the control switching signal fchg is set to "1" (torque control), and if any of S11 to S13 is negative, "0" (rotation speed control). Set to.
[0033]
For example, in the regenerative braking operation period T1 (FIG. 5) in which the fuel cut is being performed, the drive motor is performing the regenerative operation, and the generator motor is performing the power running operation, S11 is affirmative, S12 is negative, and the process proceeds to S14. The operation is performed in the rotation speed control mode. If fuel injection is started during this regenerative braking operation, S12 becomes affirmative, and the operation mode of the generator motor 2 is switched from the rotation speed control mode to the torque control mode. However, when the fuel injection start period T2 has elapsed from the start of fuel injection, S13 is denied, and the operation mode of the generator motor 2 is switched from the torque control mode to the rotation speed control mode again. The fuel injection start period T2 may be ended when, for example, the actual rotation speed of the power generation motor 2 substantially matches a power generation motor rotation speed command value Ns described later, or in order to simplify control. Alternatively, a fixed period may be set after switching of fchg from 0 (rotation speed control) to 1 (torque control) (start of fuel injection).
[0034]
When the fuel cut signal fcut switches from 1 to 0 while the target axle driving torque Tsd is negative, the control switching signal fchg switches from 0 (rotation speed control mode) to 1 (torque control mode). On the other hand, when the target axle driving torque Tsd shifts from a negative value to a positive value, so that the fuel cut signal fcut changes from 1 to 0, S1 is denied. Will be maintained. That is, when fuel injection is started by the vehicle driver stepping on the accelerator (the target axle driving torque Tsd becomes a positive value), the rotation speed control is maintained, and the engine rotation speed increases quickly. Even if the vehicle driver starts fuel injection by depressing the accelerator, if the control switching signal fchg is switched from 0 (rotational speed control) to 1 (torque control), the vehicle responds to the driver's request. The ability to follow the target rotational speed is reduced, and the torque of the generator motor changes abruptly from negative (powering) to positive (power generation), making it difficult to restart the engine.
[0035]
Referring again to FIG. 2, target engine output calculation unit 20 estimates a loss that occurs when power is generated by power generation motor 2, and adds this loss to target generated power Pgen (efficiency correction) to obtain target engine power. Find the output Pse. The method of estimating the loss of the power generation motor is based on the assumption that the loss of the power generation motor 2 at the operating point with the highest fuel efficiency when the target power generation Pgen calculated by the target power generation calculation unit 18 is generated by the engine 1 and the power generation motor 2 is set in advance. A method of obtaining a table of the generated power Pgen and referring to this table, or a method of preparing a generator motor loss map by measuring the loss for each generated power / rotational speed in advance and referring to this map And so on.
[0036]
The target engine torque calculator 21 divides the target engine output Pse by the actual engine speed to obtain an engine torque command value Ts. Instead of the actual engine rotation speed, a power generation motor rotation speed command value Ns calculated in S24 described later may be used. The engine torque command value Ts is sent to the engine controller 7 together with the fuel cut signal fcut generated by the determination unit 19, and the engine torque is controlled by controlling the throttle opening and the fuel injection amount of the engine 1 based on the value. When the fuel cut signal fcut is 1 (fuel cut), the throttle is fully closed and the fuel injection amount is controlled to 0. When the fuel cut signal fcut is 0 (fuel injection), the throttle is controlled to an opening determined by the actual engine speed and the engine torque command value Ts. When the engine torque command value Ts exceeds the achievable torque range, the engine torque is controlled to be fully open, and when the engine torque command value Ts is less than the achievable torque range, the engine is fully closed. The fuel injection amount is controlled so that the air-fuel ratio becomes a desired air-fuel ratio. Note that the determination unit 19, the target engine output calculation unit 20, the target engine torque calculation unit 21, the engine controller 7, and the like correspond to means for controlling the engine torque.
[0037]
In blocks 22 to 24, calculation and setting of the generation motor rotation speed command value Ns are performed according to the target generated power Pgen and the fuel cut signal fcut.
[0038]
The first target engine speed calculation unit 22 calculates the target engine speed so as to achieve the target generated power Pgen with the lowest fuel consumption rate. When the target generated power Pgen is positive, the first switching unit 24 selects the target engine rotation speed calculated by the first target engine rotation speed calculation unit 22 as the generation motor rotation speed command value Ns.
[0039]
The second target engine speed calculation unit 23 calculates an engine speed at which target power consumption of the generator motor (= −1 × target generated power Pgen) is realized by fully closing the throttle and fuel injection. When the target generated power Pgen is negative and the fuel cut signal fcut is 0 (fuel injection), the first switching unit 24 and the second switching unit 232 calculate the second target engine rotation speed calculation unit 23. The engine rotation speed is selected as the generator motor rotation speed command value Ns.
[0040]
The third target engine speed calculation unit 231 calculates an engine speed that achieves the target power consumption of the generator motor by fully closing the throttle and fuel cut. When the target generated power Pgen is negative and the fuel cut signal fcut is 1 (fuel cut), the first switching unit 24 and the second switching unit 232 calculate the third target engine rotation speed calculation unit 231. The engine rotation speed is selected as the generator motor rotation speed command value Ns.
[0041]
The power generation motor torque command value calculation means 25 divides the target power generation power Pgen by the actual power generation motor rotation speed to obtain a power generation motor torque command value Tg. The generation motor torque command value Tg corresponds to the generation torque when the value is positive, and corresponds to the powering torque when the value is negative. In this embodiment, since the rotation speed of the generator motor and the rotation speed of the engine are the same, the generator motor torque command value calculating means 25 may use the actual engine rotation speed instead of the actual generator motor rotation speed.
[0042]
As described above, in the present embodiment, when the fuel injection is started from the fuel cut state in the regenerative braking operation state in which the regenerative operation by the drive motor and the power running operation by the power generation motor are performed, the operation mode of the power generation motor is controlled by the rotation speed control. Since the mode is switched from the torque control mode to the torque control mode, the power consumption of the generator motor is not excessively increased immediately after the start of fuel injection, so that wasteful power consumption can be avoided, and the power storage device 6 Since the input and output of the power storage device 6 are reduced and eliminated, overdischarge of the power storage device 6 and reduction in durability can be suppressed. In particular, immediately after the start of fuel injection, the controllability of the engine torque is not stable, and the control of the electric power becomes very difficult. In this embodiment, the drivability in such a situation is effectively improved. can do.
[0043]
The target generated power calculation unit 18 may calculate the target generated power Pgen based on the SOC of the power storage device 6 and the input / output available power. That is, if the SOC is low and it is necessary to charge the power storage device, the charging power may be added to the target generated power Pgen within the range of the inputtable power, and if the SOC is high and the power of the power storage device can be used freely, input / output is possible. The target generated power Pgen may be set such that the charging power is consumed within the power range and the driving motor 3 can output the torque according to the target driving force. As described above, by correcting and calculating the target generated power Pgen based on the input / output possible power of the power storage device 6, the drive motor 3 and the power generation motor 2 can use the power generation device 2 within a range where the power storage device 6 is not overcharged or overdischarged. The difference in transmitted and received power can be positively absorbed, and the drivability can be significantly improved.
[0044]
When the target driving force Psd is a negative value (the regenerative braking side), the operation mode of the generator motor 2 is switched from the rotation speed control mode to the torque control mode when starting the fuel injection from the fuel cut state. When the target driving force Psd is a positive value (powering / driving side), as in the case where the engine starts fuel injection by depressing the accelerator pedal from the state, the switching to the torque control mode is not performed and the rotation speed control mode is switched. Since the engine speed is maintained, the engine speed is controlled with good responsiveness in accordance with the driver's request, and it is possible to prevent the engine from accidentally blowing up, and to reliably prevent the engine from starting poorly.
[Brief description of the drawings]
FIG. 1 is a configuration diagram schematically showing a hybrid vehicle to which an embodiment of the present invention is applied.
FIG. 2 is a control block diagram in the integrated controller of FIG. 1;
FIG. 3 is a flowchart showing a flow of a setting process of a fuel cut signal.
FIG. 4 is a flowchart showing a flow of a control switching signal setting process.
FIG. 5 is a time chart illustrating an operation according to the embodiment.
FIG. 6 is a time chart illustrating an operation according to a comparative example.
FIG. 7 is a graph showing engine speed-torque characteristics in a fuel cut state.
FIG. 8 is a graph showing the relationship between the number of revolutions and the torque of the generated torque during engine motoring.
[Explanation of symbols]
1. Engine
2. Generating motor (first motor generator)
3. Drive motor (second motor generator)
5 Drive wheel
6 ... Power storage device
7 ... Engine controller
8 ... Generating motor controller
9 ... Integrated controller
10 Power storage device controller
11 ... Drive motor controller

Claims (4)

A generator motor that mainly generates power using the engine as a drive source,
A drive motor that mainly drives the drive wheels;
A power storage device that is electrically connected to both the power generation motor and the drive motor and temporarily stores power,
Target driving force calculating means for calculating a target driving force according to a driver's request;
Drive motor control means for controlling the drive motor according to the target drive force,
Target power generation amount calculating means for calculating a target power generation amount of the power generation motor according to the target driving force,
An actual rotation speed detecting means for detecting the actual rotation speed of the engine or the generator motor,
Target power generation torque calculation means for calculating a target power generation torque of the power generation motor according to the target power generation amount and the actual rotation speed,
Target rotation speed calculating means for calculating a target rotation speed of the engine or the generator motor according to the target power generation amount,
Rotation speed control means for controlling the rotation speed of the generator motor toward the target rotation speed,
Torque control means for torque-controlling the power generation motor toward the target power generation torque,
Switching means for switching from rotation speed control by the rotation speed control unit to torque control by the torque control unit when fuel injection is started from an operation state involving a fuel cut of the engine;
A control device for a hybrid vehicle having: Having a storage state detection means for detecting the storage state of the power storage device,
The control device for a hybrid vehicle according to claim 1, wherein the target power generation amount calculation means calculates a target power generation amount based on the target driving force and the state of charge. The switching means switches from rotation speed control by the rotation speed control means to torque control by the torque control means when the target driving force is negative and fuel injection is started from a fuel cut state of the engine. 3. The control device for a hybrid vehicle according to 1 or 2. A first motor generator connected to the engine so that power can be transmitted;
A second motor-generator connected to the first motor-generator so as to be able to transmit power and to a driving wheel so as to be able to transmit power;
In the regenerative braking operation state in which the second motor generator is generated by the driving wheels and the engine is driven by the first motor generator so as to consume the generated power of the second motor generator, the engine is switched from the fuel cut state. When fuel injection is started, the mode is switched from a rotation speed control mode in which the first motor generator is controlled to a target rotation speed to a torque control mode in which the first motor generator is torque-controlled to a target torque. Switching means;
A control device for a hybrid vehicle having:

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