JP2004340017A - Engine shaft torque control method and engine revolution speed control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine shaft torque control method for controlling variation in shaft torque during changing moment of inertia of a fly wheel, and to provide variation in engine revolution speed during changing the same. <P>SOLUTION: An ECU judges whether the moment of inertia of the flywheel is changing or not (step S2). If it is judged that the moment of inertia of the flywheel is changing, inertial torque Tα that is absorbed into the flywheel or is discharged from the flywheel is derived (step S3) to compensate the inertia torque Tα by doing addition or subtraction (step S4). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for controlling an axial torque of an engine having a flywheel capable of changing a moment of inertia and a method for controlling an engine speed.
[0002]
[Prior art]
Generally, a flywheel is provided in an internal combustion engine. A flywheel is a device for reducing rotation fluctuation of a crankshaft by a rotating inertial mass. In addition, flywheels are known in which the moment of inertia can be changed in order to achieve both suppression of rotation fluctuation of the crankshaft and responsiveness when changing the engine rotation speed (for example, see Patent Documents 1 to 3). ).
[0003]
[Patent Document 1]
JP 10-159904 A
[Patent Document 2]
JP 11-30293 A
[Patent Document 3]
JP-A-11-44231
[0004]
[Problems to be solved by the invention]
During a change in the moment of inertia of the flywheel, inertial torque is absorbed by or released from the flywheel. Therefore, the shaft torque of the engine fluctuates under the influence of the absorption or release of the inertia torque. Similarly, the engine speed also fluctuates.
[0005]
Therefore, an object of the present invention is to suppress fluctuations in shaft torque or fluctuations in engine speed during a change in the moment of inertia of a flywheel.
[0006]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above problems.
[0007]
According to the present invention, control is performed to eliminate fluctuations in shaft torque or fluctuations in engine speed due to changes in the moment of inertia of the flywheel. That is, when the moment of inertia of the flywheel is changed, the change causes the inertia torque to be absorbed by the flywheel or to be released from the flywheel. As a result, the shaft torque of the engine fluctuates. Similarly, the engine speed also varies. Therefore, the present invention first derives the absorbed or released inertia torque. In the present invention, control is performed to increase or decrease the shaft torque so as to offset the derived inertia torque. Alternatively, control is performed to increase or decrease the shaft torque so as to offset the derived inertia torque, thereby increasing or decreasing the engine speed. Note that the inertia torque is an amount corresponding to the “inertial force” of the translational motion in the rotary motion system.
[0008]
ADVANTAGE OF THE INVENTION According to this invention, the axial torque fluctuation | variation resulting from change of the inertia moment of a flywheel can be suppressed. Alternatively, the engine speed due to the change in the moment of inertia of the flywheel can be suppressed.
[0009]
More specifically, the method of controlling the shaft torque of the engine of the present invention includes:
For an engine having a flywheel configured such that the moment of inertia can be changed, in an axial torque control method for controlling the axial torque of the engine,
A first step of deriving a basic target torque of the shaft torque;
A second step of deriving an inertia torque absorbed by or released from the flywheel by changing the moment of inertia of the flywheel;
A third step of deriving a target torque obtained by increasing or decreasing the inertia torque derived in the second step with respect to the basic target torque;
And a fourth step of controlling the shaft torque so that the target torque derived in the third step is maintained while the moment of inertia of the flywheel is being changed.
[0010]
According to the configuration of the present invention, while the inertia moment of the flywheel is being changed, the increase / decrease correction of the inertia torque absorbed into the flywheel or emitted from the flywheel is performed on the shaft torque. Therefore, the torque fluctuation during the change of the inertia moment of the flywheel is suppressed.
[0011]
Then, while the moment of inertia of the flywheel is not changed, the shaft torque may be controlled to be the basic target torque derived in the first step.
[0012]
Here, the flywheel includes a main flywheel and a sub flywheel configured to be connectable to and detachable from the main flywheel, and the moment of inertia is changed by coupling or disconnection of the sub flywheel. If configured to
In the second step, when the sub flywheel is coupled to the main flywheel, the inertia torque may be estimated from a change in angular momentum of the sub flywheel or an angular acceleration of the sub flywheel. it can.
[0013]
Further, the flywheel includes a flywheel body and a movable member configured to be movable with respect to the flywheel body, and the position of the center of gravity of the movable member moves with respect to the rotation center of the flywheel. If the moment of inertia is configured to be changed by
In the second step, the inertia torque can be estimated from the amount of change in the inertia moment that changes as the position of the center of gravity of the movable member moves.
[0014]
As a more specific control method of the engine speed of the present invention,
An engine speed control method for controlling the engine speed while the moment of inertia is changed for an engine including a flywheel configured to be able to change the moment of inertia,
A first step of deriving an error between the engine speed detected by the detection sensor that detects the engine speed and the target engine speed;
A second step of estimating an inertia torque absorbed by or released from the flywheel by changing the moment of inertia of the flywheel;
The engine speed is controlled so that the error of the engine speed derived in the first step is corrected and the variation of the engine speed corresponding to the inertia torque estimated in the second step is corrected in advance. And three steps.
[0015]
Here, the order of the first step and the second step in the present invention does not matter. The operation of correcting the error of the engine speed in the third step may be performed before or after the second step as long as it is performed after the first step. Further, the operation of correcting the fluctuation of the engine speed in the third step may be before or after the first step as long as it is after the second step. The correction of the error of the engine speed and the correction of the fluctuation of the engine speed in the third step may be performed individually or collectively.
[0016]
According to the present invention, the feedback control for correcting the error between the detected engine speed and the target speed and the feedforward control for correcting in advance the variation in the engine speed due to the change in the inertia moment of the flywheel are performed. The engine speed is controlled.
[0017]
Here, the flywheel includes a main flywheel and a sub flywheel configured to be connectable to and detachable from the main flywheel, and the moment of inertia is changed by coupling or disconnection of the sub flywheel. If configured to
In the second step, when the sub flywheel is coupled to the main flywheel, the inertia torque may be estimated from a change in angular momentum of the sub flywheel or an angular acceleration of the sub flywheel. it can.
[0018]
Further, the flywheel includes a flywheel body and a movable member configured to be movable with respect to the flywheel body, and the position of the center of gravity of the movable member moves with respect to the rotation center of the flywheel. If the moment of inertia is configured to be changed by
In the second step, the inertia torque can be estimated from the amount of change in the inertia moment that changes as the position of the center of gravity of the movable member moves.
[0019]
Here, in the configuration of each of the above-described inventions, as a method of controlling the shaft torque, a method of directly controlling the shaft torque may be employed, or a method of indirectly controlling the shaft torque may be employed. it can. The same applies to a method for controlling the engine speed. For example, by increasing or decreasing the fuel injection amount or the intake air amount, the shaft torque and the engine speed can be directly controlled. Further, by controlling the accessory, the shaft torque and the engine speed can be indirectly controlled. Specific examples of the accessory include a generator, an alternator, a motor generator, and an air conditioner compressor.
[0020]
It should be noted that the above configurations can be employed in combination as much as possible.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to them unless otherwise specified. Absent.
[0022]
(First Embodiment)
With reference to FIGS. 1 to 3, a description will be given of a shaft torque control method for an engine according to a first embodiment of the present invention. FIG. 1 is a flowchart showing a procedure for controlling the shaft torque of the engine according to the first embodiment of the present invention. FIG. 2 is a block diagram showing an engine shaft torque control system according to the first embodiment of the present invention. FIG. 3 is a time chart showing an example when the method of controlling the shaft torque of the engine according to the first embodiment of the present invention is adopted.
[0023]
<Engine shaft torque control system>
As shown in FIG. 2, an engine shaft torque control system according to the present embodiment includes an engine 100, an ECU 200 that performs various controls including an engine shaft torque control, an actuator 300 that adjusts the engine shaft torque, A sensor S for sending input data to the ECU 200; Although only one sensor S is shown in the figure, a plurality of sensors S are provided individually for the detection target. The engine 100 is provided with a flywheel 102 that reduces the rotation fluctuation of the crankshaft 101 provided in the engine 100. One of the sensors S detects information relating to the moment of inertia of the flywheel 102 and sends the detected data to the ECU 200.
[0024]
The ECU 200 also has an input processing function of inputting detection data (including information related to the inertia moment of the flywheel) detected by the sensor S, and a target value of the engine torque and a target of the engine speed based on the input data. It has an arithmetic processing function of performing an arithmetic processing for deriving a value, and an output processing function of performing an output processing to the actuator 300 based on the output data subjected to the arithmetic processing.
[0025]
<Overview of flywheel>
As described above, the engine 100 is provided with the flywheel 102. A flywheel is a device for absorbing and releasing the rotational energy of a crankshaft by a rotational inertial mass to reduce rotational fluctuation. Here, the larger the moment of inertia of the flywheel, the smaller the rotation fluctuation. However, the greater the moment of inertia of the flywheel, the lower the responsiveness when changing the engine speed. Therefore, flywheel 102 according to the present embodiment is configured to be able to change the moment of inertia. As a result, both suppression of the rotation fluctuation of the crankshaft and responsiveness when changing the engine rotation speed are achieved.
[0026]
For example, when the vehicle on which the engine 100 is mounted is running at a constant speed, it is required that the rotation fluctuation is small. On the other hand, responsiveness is required during acceleration running and deceleration running. Therefore, while traveling at a constant speed, the rotational fluctuation can be suppressed by increasing the moment of inertia of the flywheel 102. Then, during acceleration traveling or deceleration traveling, by reducing the moment of inertia of the flywheel 102, it is possible to increase the responsiveness when changing the engine rotation speed, and to improve the acceleration response or the deceleration response.
[0027]
<Torque fluctuation caused by change in moment of inertia of flywheel>
When the moment of inertia of the flywheel 102 is changed, the inertia torque is absorbed by the flywheel 102 or is released from the flywheel 102 during the change. Accordingly, the crankshaft of engine 100 is affected. If no countermeasures are taken against the change in the inertia torque, the shaft torque of the engine 100 fluctuates while the inertia moment is being changed. The fluctuation of the shaft torque may cause a driver of the vehicle equipped with the engine 100 to feel uncomfortable, for example. That is, if the shaft torque fluctuates during traveling of the vehicle, the driver accelerates or decelerates unintentionally. Further, if the shaft torque fluctuates during idling, a fluctuation occurs in which the engine speed temporarily increases or decreases even though the driver does not step on the accelerator. Therefore, in the present embodiment, when the inertia moment of the flywheel 102 is changed, the inertia torque absorbed by or released from the flywheel 102 when changing the moment of inertia of the flywheel 102 in order to suppress such shaft torque fluctuation. The shaft torque is increased or decreased so as to cancel each other.
[0028]
<Engine shaft torque control procedure>
Next, the procedure for controlling the shaft torque of the engine will be described with reference to FIG. The processing routine for controlling the shaft torque of the engine shown in FIG. 1 is appropriately repeated by the ECU 200 shown in FIG. For example, the operation may be periodically repeated during the operation of the engine, or may be periodically repeated at predetermined intervals.
[0029]
First, the ECU 200 derives the basic target torque T0 (step S1). This basic target torque T0 can be derived based on, for example, the accelerator opening (or the amount of accelerator depression). In this case, the correlation between the accelerator opening and the like and the basic target torque T0 is determined in advance. The basic target torque T0 corresponding to the accelerator opening and the like detected by the accelerator opening sensor and the like can be derived using the correlation. Specifically, the above derivation can be performed by determining the correlation using a map or an arithmetic expression. In the former case, a map defining the correlation is stored in a storage device provided in the ECU 200. Then, the ECU 200 can read this map as appropriate and derive the basic target torque T0 from the detection data such as the accelerator opening. In the latter case, the arithmetic expression defining the correlation is stored in a storage device provided in the ECU 200. Then, the ECU 200 can derive the basic target torque T0 from the detection data such as the accelerator opening degree by using this arithmetic expression as appropriate.
[0030]
Next, the ECU 200 determines whether the moment of inertia of the flywheel 102 is being changed (step S2). Here, the ECU 200 determines whether to change the moment of inertia of the flywheel 102. Therefore, the ECU 200 recognizes whether or not the moment of inertia of the flywheel 102 is being changed.
[0031]
The determination as to whether to change the moment of inertia of the flywheel 102 can be made based on the rate of change of the engine speed or the rate of change of the accelerator opening (accelerator depression amount). In other words, as described above, during acceleration running or deceleration running, responsiveness is required, so that the inertia moment of the flywheel 102 is preferably smaller. That is, the larger the rate of change of the engine speed and the rate of change of the accelerator opening, the smaller the moment of inertia of the flywheel 102 should be. Therefore, the ECU 200 can determine whether to change the moment of inertia of the flywheel 102 based on the rate of change of the engine speed and the rate of change of the accelerator opening. The change rate of the engine speed can be obtained by sequentially detecting the detection data of the engine speed detection sensor, and the change rate of the accelerator opening can be obtained by sequentially detecting the detection data of the accelerator opening sensor. You can ask.
[0032]
When it is determined in step S2 that the moment of inertia is being changed, the inertia torque Tα absorbed by or released from the flywheel 102 is derived by the change in the moment of inertia of the flywheel 102. (Step S3). The inertia torque Tα can be derived, for example, from a change in the angular momentum of the flywheel 102. That is, the time difference of the change in the angular momentum is equivalent to the inertia torque Tα. However, when the rate of change of the moment of inertia with respect to the elapsed time is constant, or when the calculation cycle is short, the inertia torque Tα is derived from [inertia torque Tα = angular momentum changed during a certain time / constant time]. No problem. For example, using an arithmetic cycle of 100 ms as a certain time, the inertia torque Tα can be derived from the angular momentum changed during this time. The angular momentum is the product of the moment of inertia and the angular velocity. The method of obtaining the change in the angular momentum differs depending on the configuration of the flywheel, and there are various methods. Here, the description is omitted. In the embodiment described below, an example of a method of obtaining a change in angular momentum will be described.
[0033]
Next, increase / decrease correction of the inertia torque Tα derived in step S3 is performed. That is, the target torque T of the engine 100 is set to T = T0 ± Tα (step S4). That is, when the inertia torque is absorbed by the flywheel 102 by Tα, T = T0 + Tα. On the other hand, when the inertia torque is released from the flywheel 102 by Tα, T = T0−Tα. If it is determined in step S2 that the moment of inertia of the flywheel 102 is not being changed, the target torque T of the engine 100 is set to T = T0 (step S5).
[0034]
Thus, the ECU 200 sequentially derives the target shaft torque. Then, the ECU 200 sequentially transmits a command signal to the actuator 300 so as to obtain the derived shaft torque.
[0035]
While the moment of inertia of the flywheel 102 is being changed, the shaft torque is absorbed by the flywheel 102 or corrected to increase or decrease the inertia torque released from the flywheel 102 by changing the moment of inertia of the flywheel 102. Therefore, it is possible to suppress the fluctuation of the shaft torque of the engine 100 while the inertia moment of the flywheel 102 is being changed.
[0036]
<Specific example of engine torque control>
A method of controlling the shaft torque of an engine using an actuator is a known technique and has various configurations and methods. The specific configuration and function of the actuator are different depending on the control method of the shaft torque. Further, as a method of controlling the shaft torque of the engine, a method of directly controlling the shaft torque may be employed, or a method of indirectly controlling the shaft torque may be employed.
[0037]
For example, the shaft torque can be directly controlled by increasing or decreasing the fuel injection amount or the intake air amount. That is, in the case of an engine with an electronic throttle, the shaft torque of the engine can be controlled by controlling the intake air amount by controlling the drive of the throttle valve. Therefore, in this case, the actuator 300 corresponds to a throttle valve. In the case of an engine with an idle speed control function, the shaft torque of the engine can be controlled by controlling the intake air amount by controlling the drive of an idle speed control valve. Therefore, in this case, the actuator 300 corresponds to an idle speed control valve. In the case of a diesel engine, the shaft torque of the engine can be controlled by controlling the fuel injection amount. Therefore, in this case, the actuator 300 corresponds to a fuel injection valve.
[0038]
Further, by controlling the accessory, the shaft torque can be indirectly controlled. In this case, the auxiliary device corresponds to the actuator 300. Specific examples of the accessory include a generator, an alternator, a motor generator, and an air conditioner compressor.
[0039]
<One example in which control in the present embodiment is performed>
Next, an example of the case where the control according to the above-described embodiment is performed will be described with reference to a time chart of FIG. In FIG. 3, L1 indicates a change over time of the moment of inertia of the flywheel 102, L2 indicates a change over time of the inertia torque absorbed by or released from the flywheel 102, and L3 indicates a target torque of the engine 100. T indicates a change over time, and L4 indicates a change over time in the shaft torque of the engine 100. In L2, the case where the inertia torque is released is positive.
[0040]
In this example, the moment of inertia of flywheel 102 is constant until time T1. Then, the moment of inertia is changed so as to decrease from time T1 to time T2. Then, after the time T2, the moment of inertia becomes constant again (L1). In this case, the flywheel 102 emits the inertia torque during the period from the time T1 when the moment of inertia is changing to the time T2 (L2). Accordingly, during this time, the target torque of the engine 100 is corrected to reduce the shaft torque by the inertia torque (L3). As a result, the axial torque of the engine 100 becomes constant without being affected by the change in the moment of inertia of the flywheel 102 (L4).
[0041]
(Second embodiment)
In the present embodiment, an example will be described in which the configuration of the flywheel in the first embodiment is made more specific. The basic configuration of the control system and the basic method of controlling the shaft torque of the engine are the same as those described in the first embodiment, and a description thereof will be omitted.
[0042]
The derivation of the inertia torque Tα in step 3 shown in FIG. 1 described above differs depending on the configuration of the flywheel. Therefore, in the present embodiment, how to derive the inertia torque Tα based on an example of a specific flywheel will be described. FIG. 4 is a block diagram showing an engine shaft torque control system according to a second embodiment of the present invention.
[0043]
<Overview of flywheel>
The flywheel 110 provided in the engine 100 according to the present embodiment includes a main flywheel 111, a sub flywheel 112, and an electromagnetic clutch 113 having a function of switching connection and disconnection of these flywheels. Further, a first rotation sensor S1 for detecting an angular velocity of the main flywheel 111 and a second rotation sensor S2 for detecting an angular velocity of the sub flywheel 112 are provided.
[0044]
When the electromagnetic clutch 113 is turned on, the sub flywheel 112 is connected to the main flywheel 111. In this case, the moment of inertia of the flywheel 110 is the sum of the moments of inertia of both flywheels. Therefore, the moment of inertia of the flywheel 110 becomes large. When the electromagnetic clutch 113 is turned off, the sub flywheel 112 is disconnected from the main flywheel 111. In this case, the moment of inertia of the flywheel 110 is only the moment of inertia of the main flywheel 111. Therefore, the moment of inertia of the flywheel 110 is small. When connecting the sub flywheel 112 to the main flywheel 111, it takes some time before the sub flywheel 112 becomes equal to the angular velocity of the main flywheel 111. Accordingly, during this time, the moment of inertia of the flywheel 110 changes gradually.
[0045]
In the flywheel 110 configured as described above, when the sub flywheel 112 is coupled to the main flywheel 111, the inertia torque absorbed by the flywheel 110 affects the shaft torque of the engine 100. On the other hand, when the sub flywheel 112 is separated from the main flywheel 111, the inertia torque is not absorbed or released, and the axial torque of the engine 100 is not affected. Therefore, in the case of the flywheel 110 according to the present embodiment, step 3 in the flowchart of FIG. 1 is as follows. That is, when making a change to increase the moment of inertia of the flywheel 110, the inertia torque Tα absorbed by this is derived, and when making a change to reduce the moment of inertia of the flywheel 110, the inertia torque Tα is Set to 0.
[0046]
<Method of deriving inertia torque Tα>
As described above, the inertia torque Tα is obtained by differentiating the change in angular momentum with time. Therefore, if the angular momentum of the flywheel is sequentially detected, and the amount of change in the angular momentum is obtained, the inertia torque Tα can be obtained. Here, when the sub flywheel 112 is coupled to the main flywheel 111, the change in the angular momentum of the flywheel 110 can be considered to be equal to the change in the angular momentum of the sub flywheel 112. Accordingly, if the amount of change in the angular momentum of the sub flywheel 112 is obtained, the inertia torque Tα can be obtained. Here, the angular momentum is the product of the moment of inertia and the angular velocity. The moment of inertia of the sub flywheel 112 is a value unique to the sub flywheel 112. Therefore, if the angular velocity of the sub flywheel 112 is sequentially detected by the second rotation sensor S2, the change amount of the angular momentum of the sub flywheel 112 can be obtained. Then, if the amount of change in the angular momentum is differentiated with respect to time, the inertia torque Tα can be obtained. However, since the calculation cycle is short, the inertia torque Tα can be obtained from [inertia torque Tα = angular momentum changed during certain time / constant time].
[0047]
In summary, when the angular velocity of the sub flywheel 112 at time t1 is ω1, the angular velocity of the sub flywheel 112 at time t2 is ω2, and the moment of inertia of the sub flywheel is I, the inertia torque Tα absorbed by the flywheel 110 Is
Tα = (I × ω2−I × ω1) / (t2−t1)
Required from.
[0048]
As described above, when the sub flywheel 112 is coupled to the main flywheel 111, while the moment of inertia of the flywheel 110 is changing, Tα is sequentially obtained, and the shaft torque is gradually increased and corrected accordingly. , The fluctuation of the shaft torque can be suppressed. The change in the angular velocity of the sub flywheel 112 can be predicted in advance. Therefore, it is possible to perform a feedforward control for estimating a change in the angular momentum and for increasing and correcting the shaft torque in advance.
[0049]
As described above, the inertia torque Tα is obtained by differentiating the change in angular momentum with time. That is, the inertia torque Tα is equal to the product of the moment of inertia and the angular acceleration. Therefore, Tα can also be determined from [Tα = moment of inertia of sub flywheel × angular acceleration of sub flywheel 112]. In this case, the angular acceleration of the sub flywheel 112 can be obtained by differentiating the angular velocity measured by the second rotation sensor S2 with respect to time.
[0050]
(Third embodiment)
In the present embodiment, a case where the configuration of the flywheel is different from that of the second embodiment will be described. The basic configuration of the control system and the basic method of controlling the shaft torque of the engine are the same as those described in the first embodiment, and a description thereof will be omitted. FIG. 5 is a block diagram showing an engine shaft torque control system according to a third embodiment of the present invention.
[0051]
<Overview of flywheel>
The flywheel 120 provided in the engine 100 according to the present embodiment includes a flywheel main body 121, a pair of movable members 122 rotatably provided with respect to the flywheel main body 121, and a rotation of the movable member 122. And a hydraulic actuator 123. Further, a rotation angle sensor S3 for detecting the rotation angle of the movable member 122 is provided. Further, a rotation sensor S4 for detecting the angular velocity of the flywheel 120 is provided. One end of each of the pair of movable members 122 is connected to the flywheel main body 121 by a pin P1, and is rotatable with respect to the flywheel main body 121. The other end of each of the pair of movable members 122 is coupled to the hydraulic actuator 123 by a pin P2, and is rotatable with respect to the hydraulic actuator 123. The hydraulic actuator 123 is configured to expand and contract by controlling the oil pressure of the oil sealed therein.
[0052]
Then, expansion and contraction of the hydraulic actuator 123 can be controlled by hydraulic control of the hydraulic actuator 123. Thus, the pair of movable members 122 respectively connected to both ends of the hydraulic actuator 123 can be rotationally controlled with respect to the flywheel main body 121. Thereby, the position of the center of gravity of each movable member 122 moves with respect to the rotation center of the flywheel 120. As a result, the moment of inertia of the flywheel 120 changes. In this manner, by rotating the movable member 122 by controlling the hydraulic pressure of the hydraulic actuator 123, the moment of inertia of the flywheel 120 can be changed and controlled.
[0053]
In the flywheel 120 thus configured, when the movable member 122 is rotated such that the center of gravity approaches the rotation center of the flywheel 120, the moment of inertia of the flywheel 120 decreases. Therefore, while the movable member 122 is rotating in this manner, the inertia torque released from the flywheel 120 affects the shaft torque of the engine 100. Further, when the movable member 122 is rotated such that its center of gravity is away from the center of rotation of the flywheel 120, the moment of inertia of the flywheel 120 increases. Accordingly, while the movable member 122 is rotating in this manner, the inertia torque absorbed by the flywheel 120 affects the shaft torque of the engine 100. Therefore, in the case of the flywheel 120 according to the present embodiment, step 3 in the flowchart of FIG. 1 is as follows. That is, when the inertia moment of the flywheel 120 is changed to be small, the inertia torque Tα released by the change is derived. When a change is made to increase the moment of inertia of the flywheel 120, the inertia torque Tα absorbed by the change is derived.
[0054]
<Method of deriving inertia torque Tα>
As described above, the inertia torque Tα is obtained by differentiating the change in angular momentum with time. Therefore, if the angular momentum of the flywheel is sequentially detected, and the amount of change in the angular momentum is obtained, the inertia torque Tα can be obtained. Here, in the case of the flywheel 120 according to the present embodiment, the moment of inertia of the flywheel body 121 is I, the mass of the movable member 122 is Mn, the distance between the center of gravity of the movable member 122 and the rotation center of the flywheel 120. Xn, and the angular velocity ω of the flywheel 120, the angular momentum L of the flywheel 120 is
L = (I + Σ (Mn × Xn ² )) × ω
Required from. As shown in FIG. 5, when the pair of movable members 122 are the same member and rotate symmetrically with respect to the rotation center of the flywheel 120,
L = (I + 2 × M × X ² ) × ω
Required from. Here, the mass of each of the pair of movable members 122 is M, and the distance between the center of gravity of the movable member 122 and the rotation center of the flywheel 120 is X. The above is the case where the size of the movable member is negligible, and more strictly, the above expression is used for the mass distributed to the movable member. In this case, instead of calculating each time, the relationship between the distance (one) representative of the position of the movable member and the moment of inertia may be mapped and used.
[0055]
Here, the inertia moment I of the flywheel body 121 and the masses Mn and M of the movable member 122 are both intrinsic values. The distances Xn and X between the center of gravity of the movable member 122 and the rotation center of the flywheel 120 can be geometrically determined from the rotation angle of the movable member 122 detected by the rotation angle sensor S3. Further, the angular velocity ω of the flywheel 120 can be detected from the rotation sensor S4. From the above, if the rotation angle of the movable member 122 and the angular velocity of the flywheel 120 are sequentially detected by the rotation angle sensors S3 and S4, respectively, the change amount of the angular momentum of the flywheel 120 can be obtained. Then, if the amount of change in the angular momentum is differentiated with respect to time, the inertia torque Tα can be obtained. However, since the calculation cycle is short, the inertia torque Tα can be obtained from [inertia torque Tα = angular momentum changed during certain time / constant time].
[0056]
As described above, while the moment of inertia of the flywheel 120 is changing, by sequentially calculating Tα and performing control for sequentially increasing and decreasing the shaft torque by that amount, the shaft torque fluctuation can be suppressed. The change in the rotation angle of the movable member 122 and the change in the angular velocity of the flywheel 120 can be predicted in advance. Therefore, it is possible to perform a feedforward control for estimating a change in the angular momentum and for increasing and correcting the shaft torque in advance.
[0057]
(Fourth embodiment)
In the present embodiment, a method of controlling the engine speed when changing the moment of inertia of the flywheel in a state where the clutch for interrupting the transmission of the power of the engine is disengaged will be described. The basic configuration of the control system is the same as that described in the first embodiment, and a description thereof will be omitted. As a case where the moment of inertia of the flywheel is changed with the clutch disengaged, for example, a case where a gear is changed can be exemplified.
[0058]
FIG. 6 is a flowchart illustrating a control procedure of an engine speed control method according to the fourth embodiment of the present invention. The processing routine for controlling the number of revolutions of the engine shown in FIG. For example, during the operation of the engine 100, the repetition may be performed periodically, or may be performed periodically at predetermined intervals.
[0059]
First, the ECU 200 derives an error between the detected engine speed and the target speed (step S1). Here, the detected engine speed is an engine speed detected by a rotation sensor or the like. The target engine speed is a target engine speed determined by the accelerator opening and the like. Next, the ECU 200 calculates the combustion injection amount x,
Fuel injection amount x = (basic fuel injection amount) ± (correction amount corresponding to the above error)
(Step S2). Here, the basic fuel injection amount is a fuel injection amount that achieves the target rotation speed when there is no disturbance.
[0060]
As described above, in steps S1 and S2, feedback control is performed to eliminate an error between the detected rotation speed and the target rotation speed.
[0061]
Next, the ECU 200 estimates the inertia torque Tα absorbed by the flywheel 102 or released from the flywheel 102 by changing the moment of inertia of the flywheel 102 (step S3). This is the same as described in the first to third embodiments, and a detailed description thereof will be omitted. Then, the ECU 200 sets the indicated fuel injection amount X to:
Instructed fuel injection amount X = (fuel injection amount x) ± (correction amount of variation in engine speed corresponding to estimated inertia torque Tα)
(Step S4).
[0062]
As described above, in the present embodiment, in steps S3 and S4, the feedforward control is performed in which the fluctuation of the engine speed corresponding to the inertia torque is corrected in advance. That is, as described in the first to third embodiments, the inertia torque Tα is absorbed by the flywheel or released from the flywheel by changing the moment of inertia of the flywheel. Then, the shaft torque of the engine fluctuates under the influence thereof, so that the engine speed also fluctuates. Then, as described in the above embodiment, the inertia torque Tα can be estimated. Therefore, the engine speed resulting from this can also be estimated. Therefore, feedforward control is performed as described above.
[0063]
In this way, the ECU 200 sequentially derives the indicated fuel injection amount X. Then, the ECU 200 sequentially transmits a command signal to a fuel injection valve (not shown) or the like so as to be the derived command fuel injection amount X. Therefore, even during the change of the moment of inertia of the flywheel 102, the fluctuation of the engine speed can be suppressed.
[0064]
In the present embodiment, after obtaining the fuel injection amount x corrected by the feedback control, the fuel injection amount x is corrected by the feedforward control to obtain the indicated fuel injection amount X. Was described. However, as long as the commanded fuel injection amount reflects both the correction by the feedback control and the correction by the feedforward control, the order of calculation does not matter. For example, it is also possible to obtain a fuel injection amount corrected by feedforward control, and to correct the fuel injection amount by feedback control to obtain an instruction fuel injection amount. In addition, the total value of the correction amount by the feedback control and the correction amount by the feedforward control is obtained, and this is corrected with respect to the basic fuel injection amount to obtain the instruction fuel injection amount. Further, in the present embodiment, the case where the control of the engine speed is performed by the fuel injection amount has been described, but it goes without saying that other methods may be used as in the case of controlling the shaft torque of the engine described above. No.
[0065]
【The invention's effect】
As described above, according to the present invention, it is possible to suppress the fluctuation of the shaft torque or the fluctuation of the engine speed during the change of the inertia moment of the flywheel.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a procedure for controlling an engine shaft torque according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing an engine shaft torque control system according to the first embodiment of the present invention.
FIG. 3 is a time chart showing an example of a case where the method of controlling the shaft torque of the engine according to the first embodiment of the present invention is employed.
FIG. 4 is a block diagram showing a shaft torque control system for an engine according to a second embodiment of the present invention.
FIG. 5 is a block diagram showing an engine shaft torque control system according to a third embodiment of the present invention.
FIG. 6 is a flowchart illustrating a control procedure of an engine speed control method according to a fourth embodiment of the present invention.
[Explanation of symbols]
100 engine
101 crankshaft
102,110,120 flywheel
111 main flywheel
112 Vice flywheel
113 Electromagnetic clutch
121 Flywheel body
122 Movable member
123 Hydraulic actuator
200 ECU
300 actuator

Claims (7)

For an engine having a flywheel configured such that the moment of inertia can be changed, in an axial torque control method for controlling the axial torque of the engine,
A first step of deriving a basic target torque of the shaft torque;
A second step of deriving an inertia torque absorbed by or released from the flywheel by changing the moment of inertia of the flywheel;
A third step of deriving a target torque obtained by increasing or decreasing the inertia torque derived in the second step with respect to the basic target torque;
A fourth step of controlling the shaft torque so as to be the target torque derived in the third step while the moment of inertia of the flywheel is being changed. Method. The shaft torque of the engine according to claim 1, wherein the shaft torque is controlled to be the basic target torque derived in the first step while the moment of inertia of the flywheel is not changed. Control method. The flywheel includes a main flywheel and a sub flywheel configured to be coupled to and decoupled from the main flywheel, such that the coupling or decoupling of the sub flywheel changes a moment of inertia. If configured for
In the second step, when the sub flywheel is coupled to the main flywheel, estimating the inertia torque from a variation in angular momentum of the sub flywheel or an angular acceleration of the sub flywheel. The method according to claim 1 or 2, wherein the shaft torque of the engine is controlled. The flywheel includes a flywheel body and a movable member configured to be movable with respect to the flywheel body, and the position of the center of gravity of the movable member moves with respect to the center of rotation of the flywheel. If the moment of inertia is configured to change,
3. The method according to claim 1, wherein, in the second step, the inertia torque is estimated from a change amount of an inertia moment that changes when a position of a center of gravity of the movable member moves. 4. How to control the shaft torque of the engine. An engine speed control method for controlling the engine speed while the moment of inertia is changed for an engine including a flywheel configured to be able to change the moment of inertia,
A first step of deriving an error between the engine speed detected by the detection sensor that detects the engine speed and the target engine speed;
A second step of estimating an inertia torque absorbed by or released from the flywheel by changing the moment of inertia of the flywheel;
The engine speed is controlled so that the error of the engine speed derived in the first step is corrected and the variation of the engine speed corresponding to the inertia torque estimated in the second step is corrected in advance. 3. A method for controlling an engine speed, the method comprising: The flywheel includes a main flywheel and a sub flywheel configured to be coupled to and decoupled from the main flywheel, such that the coupling or decoupling of the sub flywheel changes a moment of inertia. If configured for
In the second step, when the sub flywheel is coupled to the main flywheel, estimating the inertia torque from a variation in angular momentum of the sub flywheel or an angular acceleration of the sub flywheel. The method according to claim 5, wherein the engine speed is controlled. The flywheel includes a flywheel body and a movable member configured to be movable with respect to the flywheel body, and the position of the center of gravity of the movable member moves with respect to the center of rotation of the flywheel. If the moment of inertia is configured to change,
6. The engine rotation according to claim 5, wherein, in the second step, the inertia torque is estimated from a change amount of an inertia moment that changes as the position of the center of gravity of the movable member moves. How to control the number.

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