JP3711927B2 - Control device for hybrid vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device applied to output control of a motor of a hybrid vehicle.
[0002]
[Prior art]
In general, when the engine torque suddenly increases in response to depression of the accelerator pedal, torsional distortion occurs in the drive transmission system that transmits engine output to the drive wheels, and torsional vibration occurs in the drive transmission system due to the restoring force. . For this reason, immediately after the vehicle shifts to the acceleration state, the torsional vibration causes a so-called shackle vibration in the longitudinal direction of the vehicle, which is a factor that greatly reduces drivability.
[0003]
Therefore, conventionally, in order to reduce such shaki vibration, there is known a technique for controlling ignition timing in multiple stages so that the torque generated by the engine is in reverse phase with respect to the vibration phase in accordance with acceleration fluctuations during vehicle acceleration. It has been. This technology retards the ignition timing to reduce the ignition efficiency when the acceleration changes in the forward direction of the vehicle, and recovers the reduced ignition efficiency when the acceleration changes in the backward direction of the vehicle. Control is performed to advance the ignition timing.
[0004]
By controlling the ignition timing in multiple stages in this way, the torque generated by the engine is reduced when the acceleration fluctuation occurs in the front direction of the vehicle, and returned to the original magnitude when the acceleration fluctuation occurs in the rear direction of the vehicle. It comes to be. As a result, the acceleration fluctuation in the vehicle front-rear direction due to the shake vibration is canceled out, and smooth acceleration is realized.
[0005]
[Problems to be solved by the invention]
However, in the above control method, it is necessary to control the engine output with extremely accurate timing according to the vibration period. On the other hand, in an actual engine, there is a time lag between the change of the intake air amount and the change of the engine output, so that it is difficult to perform output control at an accurate timing.
[0006]
In addition, it is difficult to continuously and accurately control the output torque of the engine. As a result, the torque does not reach the target value and the vibration suppressing effect is low.
By the way, in recent years, an engine and a motor are used in combination as a power source for vehicle travel, and these are cooperatively controlled so that better driving performance can be obtained compared to conventional engine-driven vehicles. Cars have been developed and put into practical use. Even in such a hybrid vehicle, at the time of sudden acceleration, as shown in FIG. 4, a resonance state similar to the shackle vibration is generated by the restoring force of torsional distortion generated in the drive transmission system. That is, as shown in FIG. 4C, when a motor torque of about 200 Nm is suddenly generated from the stopped state and suddenly accelerated, the motor output shaft (transmission input shaft) is applied as shown in FIG. Vibrates at a frequency of about 5 Hz. As shown in FIG. 4 (a), a large vibration having a peak of about 1000 Nm is generated on the drive shaft (drive shaft) to which the motor torque is transmitted via the transmission, and FIG. As shown, the vehicle speed fluctuates greatly and drivability is greatly reduced.
[0007]
In order to cope with this, it is necessary to take some vibration countermeasures. However, in a hybrid vehicle, the engine clutch is disconnected and the vehicle is controlled by motor drive at the time of starting. Therefore, vibration reduction cannot be achieved by multistage control of the engine. Therefore, in the current HEV control, when the motor torque is increased, the start clutch is gradually directly connected from the slip state, thereby suppressing the generation of torsional distortion due to a sudden increase in motor torque and preventing resonance. Yes.
[0008]
However, in order to maximize the performance of the motor and improve the acceleration performance, it is originally desirable to directly connect the starting clutch from the beginning, and in fact, a test run is performed in which the motor torque is increased while the clutch is directly connected. However, the resonance level became extremely large, and the drivability was greatly impaired.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a hybrid vehicle control device that can reduce the resonance level without impairing acceleration.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a control apparatus for a hybrid vehicle according to the present invention includes an input shaft to which torque of an engine or a motor as a power source for running a vehicle is input, an output shaft that transmits driving force to wheels, When it is detected whether or not a predetermined driving state in which resonance of the vehicle drive system occurs during acceleration of the vehicle is established, and it is detected that the predetermined driving state is established , when increasing the torque of the motor, Output control means for changing the torque of the motor so as to increase in a plurality of steps is provided.
[0010]
Therefore, the output control means controls the motor torque that is excellent in control response and accuracy to suppress the resonance when a predetermined operation state in which resonance occurs during vehicle acceleration is established, and the torque is controlled in a plurality of steps. Increase in shape. The motor torque is input to the input shaft and transmitted to the wheels via the output shaft.
At this time, the increment of the torque of the motor is divided into a plurality of stages of the first stage and the second and subsequent stages, and the timing at which the stepped motor torque of the second and subsequent stages is in reverse phase with respect to the resonance phase. It is desirable to output with. That is, the motor torque after the second step is output at the timing when the torsional distortion generated in the drive transmission system by the output of the first step of the motor torque is restored. Thereby, the restoring force of the torsional strain is canceled by the driving force generated by the motor torque after the second step (claim 2).
[0011]
The output control means increases the torque of the motor in steps of a plurality of steps when it is detected that the predetermined operation state is established when the vehicle is driven by the engine and the motor. You may make it change so that it may do (Claim 3).
Further, the output control means changes so as to increase the torque of the motor in a plurality of steps when it is detected that the predetermined operation state is established when the vehicle is driven by the engine. (Claim 4).
[0012]
Alternatively, the output control means changes so as to increase the torque of the motor in steps of a plurality of steps when it is detected that the predetermined driving state is established when the vehicle is running by the motor. (Claim 5).
The output control means is connected to an accelerator opening sensor for detecting an accelerator pedal opening and a vehicle speed sensor for detecting a vehicle speed. The output control means includes the accelerator opening sensor, the vehicle speed sensor, Based on this information, it may be determined whether or not the predetermined operation state in which resonance occurs is established (claim 6).
In this case, it is preferable that the predetermined driving state is a state in which the driver is about to accelerate suddenly from low speed traveling when the vehicle speed is below a threshold value and the change amount of the opening amount of the accelerator pedal exceeds the threshold value. Item 7).
Further, when the output control means detects that the predetermined operation state is established when the vehicle is driven by the engine or when the vehicle is driven by the engine and the motor, and performs an increase in the first stage of the torque by the engine torque by controlling the engine, may be performed an increased stepwise torque after the second stage by the motor torque to control the motor.
[0013]
As a result, the stepped torque in the first stage is started up by an engine that can exert a larger power than the motor, and the stepped torque in the second and subsequent stages is controlled responsiveness and accuracy compared to the engine. It is started up by a motor superior in the aspect of ( 8 ).
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 3 show a control apparatus for a hybrid vehicle as an embodiment of the present invention. FIG. 1 is a schematic diagram showing the overall configuration of the hybrid vehicle. FIG. 2 is a flow of acceleration control in the control apparatus. FIG. Further, FIG. 3 is a diagram for explaining the operation and effect, and is a diagram showing a state of motor torque output control and a vibration state generated in the drive transmission system thereby.
[0015]
In FIG. 3, the characteristics relating to the output control of the present embodiment are indicated by solid lines, and the characteristics relating to the conventional output control shown in FIG. 4 are indicated by dashed lines for comparison.
As shown in FIG. 1, the hybrid vehicle 1 according to the present embodiment includes an engine 2, a motor 3, a CVT (continuously variable transmission) 4 and a controller (ECU) 10 as main components.
[0016]
The engine 2 is configured as a general internal combustion engine, and an output shaft 2a thereof is connected to an input shaft 4a of the CVT 4 via an engine clutch 5, and left and right drive shafts (drive shafts or drive shafts) are connected via the CVT 4 and a differential device 9. ) Drive torque is transmitted to 8R and 8L to drive the drive wheels 8.
The motor 3 is configured as an electric motor / generator (motor generator; M / G) that operates as an electric motor when supplied with electric power and can operate as an electric generator when receiving rotational driving torque when the vehicle 1 is decelerated. The motor 3 shares its output shaft with the input shaft 4a of the CVT 4. When the motor 3 operates as an electric motor, the engine 2 and the CVT 4 are directly driven to rotate via the input shaft 4a, and when the motor 3 operates as a generator, the input shaft 4a. Rotational drive torque is input from. The electric power generated by the motor 3 is stored in a battery (not shown). When the driving torque of the motor 3 is required, the electric power stored in this battery is supplied to the motor 3. It has become.
[0017]
The engine clutch 5 is interposed between the engine 2 and the motor 3 so as to connect / disconnect the output shaft 2a of the engine 2 and the input shaft 4a of the CVT 4 and is connected / disconnected according to the travel mode. For example, when traveling using only the output of the engine 2 or traveling using the engine 2 and the motor 3 together, the clutch 5 is connected to transmit the output of the engine 2 to the CVT 4. On the other hand, when the vehicle travels only by the motor 3, the engine 2 is stopped and the clutch 5 is disengaged so that the engine 2 does not become a load on the motor 3 and the travel load is reduced.
[0018]
Between the CVT 4 and the differential (differential device) 9, an output clutch 6 that connects and disconnects the output shaft 4 b of the CVT 4 and the propeller shaft 13 is provided. When starting, the clutch 6 is connected to transmit the power of the engine 2 or the motor 3 to the drive wheel side. When the vehicle is stopped, the clutch 6 is released and the downstream drive system below the differential 9 is disconnected. Can be used to generate electricity. At the time of starting, as in the prior art, the power of the engine 2 or the motor 3 can be gradually transmitted from the slip state to the driving wheel side to start smoothly.
[0019]
The controller (output control means) 10 is a control device for cooperatively controlling the engine 2 and the motor 3, and is a storage device (ROM, RAM, etc.) for storing an input / output device (not shown), a control program, a control map, and the like. ), A central processing unit (CPU), a counter, and the like.
An accelerator opening sensor (APS) 11 for detecting the opening of the accelerator pedal and a vehicle speed sensor 12 for detecting the vehicle speed are connected to the input side of the controller 10, and the motor 3 is connected to the output side of the controller 10. The control circuit 3a and the fuel injection valve (not shown) of the engine 2 are connected. Then, the controller 10 determines whether or not an operating state in which resonance occurs is established based on information from the sensors 11 and 12 during acceleration, and when such an operating state is established, the motor is controlled by two-stage torque control. The motor torque is controlled so that the output of No. 3 increases stepwise. In other words, when the accelerator operation is performed at a vehicle speed smaller than a predetermined threshold, the amount of change ΔAPS in the accelerator opening is calculated by the APS 11, and resonance occurs in a sudden acceleration state in which the value of ΔAPS is larger than the predetermined threshold. It is determined that a predetermined operating state is established. Then, it calculates a required torque for the vehicle operating state corresponding to the accelerator operation of the driver has become so that increase stepwise divides the required torque in two steps. That is, the increments of the motor torque so that increase in two stages (hereinafter, referred to such a control two-stage torque control).
[0020]
At this time, the second stage motor torque is set to rise at a timing opposite to the resonance phase of the drive transmission system (the output shaft 4b, the differential 9, the drive shafts 8R, 8L, etc.). That is, the second stage motor torque is output at the timing when the torsional distortion generated in the drive transmission system due to the first stage motor torque is restored in the restoring direction. Thereby, the action in the restoring direction by the restoring force of the drive transmission system and the action in the driving direction by the second stage motor torque cancel each other, and the occurrence of resonance is suppressed.
[0021]
The time interval from the output of the first stage torque to the output of the second stage torque and the rising slope of the motor torque at each step use preset values. These values may be increased or decreased according to the vehicle speed, the accelerator opening amount, etc. in consideration of fluctuations in the resonance period and amplitude. That is, the resonance period and amplitude may be mapped in advance with respect to the vehicle speed, the accelerator opening amount, and the like, and this map may be referred to when performing the two-stage torque control.
[0022]
Further, the first-stage torque distribution and the second-stage torque distribution are calculated based on a control map using the vehicle speed as a parameter. Specifically, when starting or when the vehicle speed is extremely small, control is performed so that the torque distribution of the first stage and the second stage is equal, and the distribution ratio of the second stage is reduced as the speed increases. When the vehicle is traveling at a speed near the threshold value, the first stage torque distribution is controlled to be larger than the second stage. Thus, by changing the torque distribution, the resonance of the drive transmission system at a low vehicle speed can be more effectively prevented.
[0023]
Note that the relationship between the accelerator opening and the amount of change ΔAPS and the magnitude of resonance may be mapped in advance, and the torque distribution may be changed based on this relationship.
Since the hybrid vehicle control apparatus according to the embodiment of the present invention is configured as described above, control is performed according to the flow shown in FIG. 2 in the case of rapid acceleration.
[0024]
That is, the controller 10 first determines whether or not the vehicle 1 is traveling while the motor is running or using both the engine 2 and the motor 3 (step S1). In addition, based on the detection results of the APS 11 and the vehicle speed sensor 12, it is determined whether or not the vehicle 1 is in a predetermined driving state. That is, if the vehicle speed falls below the threshold value (step S2) and the change amount ΔAPS of the accelerator opening amount exceeds the threshold value (step S3), it is determined that the driver is going to accelerate rapidly from the low speed running (predetermined driving state). Then, the output of the motor 3 is increased stepwise by the two-stage torque control (step S4).
[0025]
When the engine is traveling or traveling in a low acceleration state, the outputs of the engine 2 and the motor 3 are controlled by conventional control (step S5).
As described above, according to the present control device, when a large torsional distortion occurs in the drive transmission system, such as when starting or when suddenly accelerating from a low speed state, The first-stage torque distributed in proportion is started, and then the remaining torque (second-stage torque) is raised at a timing that is in reverse phase to the resonance phase of the drive transmission system generated by this first-stage torque. Therefore, the second stage torque and the strain restoring force cancel each other.
[0026]
At this time, the torque control in each step is performed using the motor 3 that can continuously change the torque as compared with the engine 2 and is excellent in control responsiveness. The output size and timing can be changed continuously. Therefore, accurate and fine-tuned control is possible according to the driving operation of the driver, the running state, etc., and the resonance during acceleration is more effective than the two-stage control using only the engine 2 performed by retarding the ignition timing. It is suppressed, and drivability can be improved without impairing acceleration.
[0027]
As a result, the vibration of the drive transmission system is greatly suppressed as shown by the solid line in FIG. 3, and the conventional control in which the motor torque is raised in one stage is shown in the drive shafts 8R and 8L (shown by the broken line in FIG. 3). Compared to the above, it could be suppressed to about 10%.
That is, as shown in FIG. 3C, the motor torque of about 200 Nm required for sudden acceleration is divided into torques that increase in half steps in half steps, and the drive generated by the first-stage torque output. Since the second stage motor torque is output at the timing at which the torsional distortion of the transmission system is restored, as shown in FIG. The rotation of the shaft 4a is smooth. As a result, the vibration of the drive shaft 4b to which the motor torque is transmitted is also reduced, and as shown in FIG. 3A, the resonance amplitude can be suppressed to about 1/10 compared to the conventional control. .
[0028]
Accordingly, as shown in FIG. 3 (b), the change in the vehicle speed becomes smooth, and the start acceleration performance can be improved without impairing drivability.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
[0029]
For example, in the above-described embodiment, the conventional control is performed when only the engine travels. However, in such a case, the torque may be raised by two-stage torque control based on the motor output during acceleration. Thereby, vibration can be effectively suppressed.
Further, in the above-mentioned two-stage control, the first stage torque rise is caused to be performed by the engine 2 capable of exerting a larger power than the motor 3, and accurately at a timing opposite to the resonance caused by the engine torque. The second and subsequent torques that need to be output controlled may be raised by the motor 3 that is superior to the engine 2 in terms of responsiveness and accuracy. In this case, the vibration can be more effectively suppressed than the conventional two-stage torque control only by the engine 2 by the accurate torque control by the motor 2 while smoothly raising the first-stage torque.
[0030]
Furthermore, the control device of the present invention is for suppressing vibration of the drive system by motor assist during acceleration traveling, and does not depend on the configuration of the drive transmission system, such as the arrangement of the clutch, and has various structures. Can be applied. For example, in the configuration shown in FIG. 1, the present invention can also be applied to a hybrid vehicle in which the motor 3 assists the engine 2 having a structure in which the clutches 5 and 6 are eliminated and a clutch is provided between the motor 3 and the CVT 4. Of course, the present invention can also be applied to an electric vehicle in which the vehicle 1 is driven only by the motor 3.
[0031]
【The invention's effect】
As described above in detail, according to the present invention, torque control at the time of acceleration can be continuously generated as compared with the engine, and furthermore, it is performed by a motor having excellent control response. Fine control can be performed according to the state of vibration, and vibration suppressing action can be more effectively exhibited than torque control of only the engine.
[0032]
In addition, since the stepped motor output after the second stage is performed at a timing opposite to the phase of the resonance, the action in the restoring direction due to the resonance and the action in the driving direction due to the motor output cancel each other, and vibration Is suppressed (claim 2).
Such a vibration suppressing action is exhibited in various running conditions such as when the engine is running, when the motor is running, or when the engine and the motor are used together (Claims 3 to 5).
[0033]
In addition, when the engine is running or when the engine and motor are used in combination, the first stage output is carried by the engine, and the second and subsequent stages are carried by the motor. The motor can start up smoothly by force, and the vibration generated by the motor that has a continuous torque change compared to the engine and excellent control response to the resonance generated by the engine output of the first stage. It is possible to perform fine control according to the above (claim 8 ).
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an overall configuration of a hybrid vehicle according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a flow of control by the hybrid vehicle control device in one embodiment of the present invention.
3 is a diagram for explaining the effect of control by the hybrid vehicle control device according to the embodiment of the present invention, and corresponds to FIG. 4; FIG.
FIGS. 4A and 4B are diagrams for explaining a problem of a conventional hybrid vehicle control device, in which FIG. 4A is a diagram showing a state of resonance generated in a drive shaft, and FIG. 4B is a vehicle speed generated by such resonance; (C) is a diagram illustrating the timing of motor torque output control, and (d) is a diagram illustrating the vibration of the motor output shaft that accompanies this timing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vehicle 2 Engine 3 Motor 4a Input shaft 4b Output shaft 10 Controller (output control means)

Claims (8)

A control device for a hybrid vehicle having an engine and a motor as a power source for driving the vehicle,
An input shaft for inputting the torque of the engine or motor;
An output shaft that transmits driving force to the wheels;
When it is detected whether or not a predetermined driving state in which resonance of the vehicle drive system occurs during acceleration of the vehicle is established, and it is detected that the predetermined driving state is established , when increasing the torque of the motor, A control device for a hybrid vehicle, comprising: output control means for changing the torque of the motor so as to increase the torque in a plurality of steps. The increment of the torque of the motor is divided into a plurality of stages, the first stage and the second and subsequent stages.
2. The control apparatus for a hybrid vehicle according to claim 1, wherein the stepped motor torque after the second stage is output at a timing opposite to the phase of the resonance.   The output control means increases the torque of the motor in steps of a plurality of steps when it is detected that the predetermined driving state is established when the vehicle is driven by the engine and the motor. The control apparatus for a hybrid vehicle according to claim 1 or 2, wherein   When it is detected that the predetermined operation state is established when the vehicle is driven by the engine, the output control means drives the motor and increases the torque of the motor in a plurality of steps. 3. The control device for a hybrid vehicle according to claim 1, wherein the control device is changed so as to increase.   The output control means changes the torque of the motor so as to increase in a plurality of steps when it is detected that the predetermined operation state is established when the vehicle is driven by the motor. The hybrid vehicle control device according to claim 1, wherein the control device is a hybrid vehicle control device. The output control means is connected to an accelerator opening sensor that detects the opening of the accelerator pedal and a vehicle speed sensor that detects the vehicle speed,
  The said output control means judges whether the said predetermined driving | running state in which resonance generate | occur | produces based on the information of the said accelerator opening sensor and the said vehicle speed sensor was materialized. The control apparatus of the hybrid vehicle of any one of Claims. The predetermined driving state is a state in which the driver is about to accelerate rapidly from low-speed driving when the vehicle speed is below a threshold value and the amount of change in the opening amount of the accelerator pedal exceeds the threshold value. 6. The hybrid vehicle control device according to 6. A control device for a hybrid vehicle having an engine and a motor as a power source for driving the vehicle,
An input shaft for inputting the torque of the engine or motor;
An output shaft that transmits driving force to the wheels;
It is detected whether or not a predetermined driving state in which resonance of a vehicle drive system occurs during acceleration of the vehicle and the vehicle is driven by the engine or driven by the engine and the motor. When it is detected that the predetermined operating state is established , the torque increment is divided into a plurality of stages of the first stage and the second and subsequent stages when the torque is increased. as is, the engine torque by controlling the engine and performs an increase in the first stage of the torque, and an output control means for performing an increase in the torque second stage after the motor torque by controlling the motor A control device for a hybrid vehicle, characterized in that

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