JP2007162466A - Solenoid control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate effect of magnetic hysteresis and catching while inhibiting fluctuation of amplitude and displacement electricity carry quantity in a solenoid control device. <P>SOLUTION: ECU for a solenoid control device performs a process based on integration operation of rail pressure deviation and varies frequency of control signal according to calculated integration term when duty ratio of control signal is calculated. Since absolute value of the integration term is larger as absolute value of the rail pressure deviation is larger, influence of magnetic hysteresis and catching on displacement of a valve element is larger as absolute value of the integration term is larger, it can be estimated that it gets difficult to eliminate rail pressure deviation. Then, if frequency of control signal is varied according to the integration term, influence of magnetic hysteresis and catching can be eliminated while inhibiting fluctuation of amplitude and displacement of electricity carry quantity. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solenoid control device that controls displacement of a driven object by controlling an energization amount to a solenoid coil.

[Conventional technology]
Conventionally, a solenoid coil that is energized to generate a magnetic attraction force, a driven object that is driven and displaced by the magnetic attraction force, and a control signal for controlling the energization amount to the solenoid coil are output, and the control signal 2. Description of the Related Art A solenoid control device including a control unit that controls the amount of current supplied to a solenoid coil by manipulating the duty ratio is known.
The driven object of this solenoid control device is, for example, a valve body that varies the flow area of the fluid, and the solenoid control device drives and controls the valve body by controlling the amount of current supplied to the solenoid coil. The area is varied (see, for example, Patent Document 1).

[Problems with conventional technology]
Incidentally, as shown in FIG. 5, the correlation between the energization amount to the solenoid coil (hereinafter abbreviated as the energization amount) and the displacement amount of the driven object (hereinafter abbreviated as the displacement amount) The displacement amount may not show a one-to-one correspondence with the energization amount.

  For example, FIG. 5A shows the influence of magnetic hysteresis, and the displacement amount when the energization amount increases is smaller than the displacement amount when the energization amount decreases. FIG. 5B shows the influence of the catch, and shows the influence of the catch that occurs when the amount of energization is increased and the displacement is raised from zero. In this case, the foreign matter is caught in a state where the displacement amount is zero, and even if the energization amount is increased, the displacement amount is zero until the magnetic attraction force overcomes the resistance force such as the catch. On the other hand, the displacement amount when the energization amount decreases linearly decreases with respect to the energization amount.

And since such non-one-to-one correspondence adversely affects control accuracy, it is preferable to eliminate magnetic hysteresis and catching as early as possible. By the way, the influence of magnetic hysteresis and catching becomes smaller as the frequency of the control signal is lower. That is, as shown in FIG. 6, even when the duty ratio is the same, the lower the frequency, the larger the amplitude of the energization amount and the amplitude of the displacement amount. For this reason, the lower the frequency, the more the magnetic hysteresis is relaxed and the easier it is to remove foreign substances that cause a catch. However, since it is preferable that the amplitude of the energization amount is as small as possible and the variation in the displacement amount is as small as possible, the frequency is preferably as high as possible. Therefore, if the frequency is increased in order to suppress fluctuations in the energization amount, there is a problem that the influence of magnetic hysteresis and catching cannot be reduced.
JP 2001-82230 A

  The present invention has been made to solve the above problems, and its purpose is to eliminate the effects of magnetic hysteresis and catching while suppressing fluctuations in the amplitude and displacement of the energization amount in the solenoid control device. It is in.

[Means of Claim 1]
The solenoid control device according to claim 1 is a solenoid coil that is energized to generate a magnetic attractive force, a driven object that is driven and displaced by the magnetic attractive force, and a control for controlling an energization amount to the solenoid coil. Control means for outputting a signal and controlling the energization amount to the solenoid coil by manipulating the duty ratio of the control signal. The control means grasps the displacement instruction amount indicating the displacement amount from the reference position of the driven object, and calculates at least the deviation between the actual value and the target value in the displacement instruction amount when calculating the duty ratio. Processing based on the integration operation is performed, and the frequency of the control signal is varied according to the calculated value based on the integration operation.

  The absolute value of the calculated value (referred to as an integral term) based on the integral operation increases as the absolute value of the deviation between the actual value and the target value (referred to as displacement instruction amount deviation) in the displacement instruction amount increases. Accordingly, it can be estimated that the larger the absolute value of the integral term, the greater the influence of magnetic hysteresis and catching, and the displacement instruction amount deviation is more difficult to be eliminated.

  For this reason, if the frequency of the control signal is varied according to the integral term, the magnetic hysteresis can be relaxed or the foreign matter causing the catch can be removed depending on the degree of the influence of the magnetic hysteresis or the catch. it can. For this reason, even if the frequency is temporarily lowered, the influence of magnetic hysteresis and catching can be eliminated while suppressing fluctuations in the amplitude and displacement of the energization amount.

[Means of claim 2]
According to the solenoid control device of the second aspect, the control means reduces the frequency of the control signal when the absolute value of the integral term increases.
As a result, when the increase in the absolute value of the integral term is caused by magnetic hysteresis or catching, the most appropriate countermeasure (that is, frequency reduction of the control signal) can be taken.

[Means of claim 3]
According to the solenoid control device of the third aspect, the control means increases the frequency of the control signal when the absolute value of the integral term becomes smaller than the predetermined threshold after reducing the frequency of the control signal.
As a result, if the absolute value of the integral term decreases, the frequency of the control signal increases, so that fluctuations in the amplitude and displacement of the energization amount can be minimized.

[Means of claim 4]
According to the solenoid control device of the fourth aspect, the control means has a characteristic used when calculating the duty ratio when the absolute value of the integral term is equal to or greater than the predetermined threshold even after the frequency of the control signal is reduced. To correct.
If the integral term is not reduced even if the frequency of the control signal is reduced, there is a possibility that some characteristic related to the control of the energization amount is changed, not the displacement instruction amount deviation due to magnetic hysteresis or catching. The characteristics relating to the control of the energization amount are used for calculating the duty ratio in some form. Therefore, by correcting the characteristic used when calculating the duty ratio, that is, the characteristic related to the control of the energization amount, the displacement instruction amount deviation can be converged to zero at an early stage.

[Means of claim 5]
According to the solenoid control device of the fifth aspect, the driven object is a valve body of an intake metering valve that forms a part of the fuel supply pump that constitutes the pressure accumulation type fuel injection device, and the control means includes a displacement instruction. After grasping the fuel pressure of the common rail that constitutes the accumulator fuel injection device as a quantity, and performing the process based on the integral action for the deviation between the actual value and the target value in the fuel pressure of the common rail, and reducing the frequency of the control signal If the absolute value of the integral term is equal to or greater than a predetermined threshold value, the correlation characteristic between the supply amount by the fuel supply pump and the energization amount to the solenoid coil is corrected.

  The solenoid control device of the best mode 1 includes a solenoid coil that is energized to generate a magnetic attractive force, a driven object that is driven and displaced by the magnetic attractive force, and a control signal for controlling the energization amount to the solenoid coil And a control means for controlling the energization amount to the solenoid coil by manipulating the duty ratio of the control signal. The control means grasps the displacement instruction amount indicating the displacement amount from the reference position of the driven object, and calculates at least the deviation between the actual value and the target value in the displacement instruction amount when calculating the duty ratio. Processing based on the integration operation is performed, and the frequency of the control signal is varied according to the calculated value based on the integration operation.

  The control means reduces the frequency of the control signal when the absolute value of the calculated value based on the integration operation increases. Then, after reducing the frequency of the control signal, the control means increases the frequency of the control signal when the absolute value of the calculated value based on the integration operation is smaller than a predetermined threshold. In addition, the control means corrects the characteristics used when calculating the duty ratio when the absolute value of the calculated value based on the integration operation is equal to or greater than a predetermined threshold even after the frequency of the control signal is reduced.

  Further, according to this solenoid control device, the driven object is a valve body of an intake metering valve that forms a part of the fuel supply pump that constitutes the accumulator fuel injection device, and the control means uses the displacement instruction amount as Comprehend the fuel pressure of the common rail that makes up the accumulator fuel injection system, perform the processing based on the integration operation for the deviation between the actual value and the target value in the fuel pressure of the common rail, and integrate even after reducing the frequency of the control signal When the absolute value of the calculated value based on the operation is equal to or greater than a predetermined threshold, the correlation characteristic between the supply amount by the fuel supply pump and the energization amount to the solenoid coil is corrected.

[Configuration of Example 1]
The configuration of the solenoid control device 1 according to the first embodiment will be described with reference to FIGS. 1 and 2.
First, the structure of the pressure accumulation type fuel injection device 2 to which the solenoid control device 1 is applied will be described with reference to FIG. The accumulator fuel injector 2 is an apparatus that injects and supplies high-pressure fuel accumulated in an accumulator such as a common rail 3 to each cylinder of a four-cylinder diesel engine (not shown: hereinafter referred to as an engine). is there.

  As shown in FIG. 1, the pressure accumulation type fuel injection device 2 pumps up fuel from a common rail 3 for accumulating fuel in a high pressure state and a fuel tank 4, regulates the pumped fuel, increases the pressure, and supplies the fuel to the common rail 3. A fuel supply pump 5, an injector 6 that is mounted in each cylinder of the engine and injects fuel accumulated in the common rail 3 into the cylinder, and a rail pressure sensor that detects fuel pressure (hereinafter referred to as rail pressure) of the common rail 3. 7, an electronic control unit (ECU) 8 that synthesizes control signals for controlling the fuel supply pump 5, the injector 6, and the like based on detection values of the rail pressure sensor 7 and other sensors, and input of control signals from the ECU 8 And drive circuits 9 and 10 for supplying power to the fuel supply pump 5 and the injector 6.

  Here, the fuel supply pump 5 is supplied from a low pressure pump 14 for pumping fuel from the fuel tank 4, a suction metering valve 15 for sucking and metering fuel supplied from the low pressure pump 14, and a suction metering valve 15. The high-pressure pump 16 and the like that supply the fuel to the common rail 3 after increasing the pressure of the fuel. The intake metering valve 15 is disposed in a fuel flow path 17 that guides fuel from the low pressure pump 14 to the high pressure pump 16, operates by receiving power supply from the drive circuit 9, and adjusts the opening of the fuel flow path 17 to adjust the common rail 3. Metering the fuel supplied to

Next, the configuration of the solenoid control device 1 will be described with reference to FIG.
The solenoid control device 1 is applied to drive control of the intake metering valve 15. Therefore, the solenoid control device 1 is a drive unit of the intake metering valve 15, which is a solenoid coil 20 that is energized to generate a magnetic attractive force, and a driven object that is driven and displaced by the magnetic attractive force, The valve element 21 for adjusting the opening degree of the fuel flow path 17 and a control signal for controlling the energization amount to the solenoid coil 20 are output, and the solenoid coil 20 is energized by operating the duty ratio of the control signal. It is comprised from ECU8 as a control means which controls quantity.

  The solenoid coil 20 is energized from the drive circuit 9 and generates a magnetic attractive force having a strength corresponding to the energization amount.

  The valve body 21 adjusts the opening degree of the fuel flow path 17 by being displaced according to the strength of the magnetic attractive force. Further, the valve body 21 is biased in a direction to reduce the opening degree of the fuel flow path 17 by the magnetic attraction force, and the return spring 22 reverses the direction of the magnetic attraction force (the opening degree of the fuel flow path 17 is reduced). Energized in the direction of increasing). That is, the intake metering valve 15 is a normally open type in which the opening of the fuel flow path 17 is maximized when the energization of the solenoid coil 20 is stopped.

  The ECU 8 is a microcomputer having a CPU that performs control processing and arithmetic processing, a storage device that stores various programs and data, an input device, and an output device. The ECU 8 performs various arithmetic processes based on detection signals input from the rail pressure sensor 7 and other sensors, and controls to drive and control the intake metering valve 15 and the injector 6 of the fuel supply pump 5. Combine and output signals.

  For example, the ECU 8 controls the fuel supply amount Q to the common rail 3 by the fuel supply pump 5 in order to adjust the rail pressure in accordance with the operating state of the engine. The ECU 8 controls the supply amount Q by controlling the energization amount Iscv to the solenoid coil 20.

  That is, the ECU 8 calculates a target value of the rail pressure according to the operating state of the engine and calculates a command value for the supply amount Q required to achieve the target value. Then, the ECU 8 applies the command value of the supply amount Q to the characteristic line a indicating the correlation between the energization amount Iscv and the supply amount Q (see FIG. 3), calculates the command value of the energization amount Iscv, and further calculates the energization amount Iscv. The duty ratio of the control signal corresponding to the command value is calculated. Then, the ECU 8 synthesizes and outputs a control signal based on the calculated duty ratio. As a result, a magnetic attractive force having a strength corresponding to the command value of the energization amount Iscv is generated, and the opening degree of the fuel flow path 17 is adjusted to a magnitude corresponding to the command value of the supply amount Q.

  Further, the ECU 8 grasps the displacement instruction amount indicating the displacement amount from the reference position of the valve body 21 in the control of the energization amount Iscv, and also the deviation between the actual value and the target value regarding the displacement instruction amount (displacement instruction amount deviation). On the other hand, at least processing based on the integration operation is performed, and the frequency of the control signal is varied according to the calculated value (integration term) based on the integration operation. The purpose of changing the frequency is mainly to eliminate the influence of magnetic hysteresis and catching on the displacement of the valve body 21. The reference position of the valve body 21 is the position of the valve body 21 when the solenoid coil 20 is not energized.

  Then, the ECU 8 selects the rail pressure as the displacement instruction amount, and grasps the rail pressure by receiving the input of the detected value of the rail pressure from the rail pressure sensor 7. Further, the ECU 8 calculates a deviation between the detected value related to the rail pressure and the target value (rail pressure deviation) as the displacement instruction amount deviation, and performs a PID calculation on the rail pressure deviation to calculate a command value for the supply amount Q. To do. Then, the ECU 8 performs processing based on the integration operation in the PID calculation for the rail pressure deviation to calculate the integral term, and varies the frequency of the control signal according to the calculated integral term.

  In the variable frequency, the ECU 8 reduces the frequency of the control signal when the absolute value of the integral term increases. In addition, after reducing the frequency of the control signal, the ECU 8 determines that the influence of magnetic hysteresis or catching has been removed if the absolute value of the integral term becomes smaller than a predetermined threshold, and increases the frequency of the control signal. Furthermore, even after the frequency of the control signal is reduced, the ECU 8 determines that some characteristic relating to the control of the energization amount Iscv has changed if the absolute value of the integral term is equal to or greater than a predetermined threshold, and sets the characteristic line a. Correct it.

  For example, even if the frequency of the control signal is reduced, if the integral term is calculated as a positive number and the absolute value of the integral term is greater than or equal to a predetermined threshold, some characteristic changes and the detected value of the rail pressure increases. It may be difficult to do. That is, even if the energization amount Iscv is the same, the supply amount Q may decrease. Therefore, the characteristic line a is corrected as shown in FIG. That is, in the characteristic line a, a portion where the supply amount Q decreases with increasing energization amount Iscv is translated to the increase side of the energization amount Iscv, and the supply amount Q is constant with increase in energization amount Iscv. Is extended to the increasing side of the energization amount Iscv. Thereby, the command value of the supply amount Q with respect to the command value of the same energization amount Iscv can be substantially increased.

[Control Method of Example 1]
A control method using the solenoid control device 1 according to the first embodiment will be described with reference to a flowchart shown in FIG.
First, in step S1, a detected value of rail pressure is captured. Next, in step S2, a rail pressure deviation is calculated. The target value of the rail pressure used for calculating the rail pressure deviation is calculated according to the operating state of the engine. Next, in step S3, an integral term is calculated using the rail pressure deviation. The integral term is calculated when the command value of the supply amount Q is calculated by performing PID calculation on the rail pressure deviation.

  Next, in step S4, it is determined whether or not it is necessary to reduce the frequency of the control signal based on the integral term. That is, it is determined whether or not it is necessary to remove the influence of magnetic hysteresis and catching on the displacement of the valve body 21. If it is determined that the frequency needs to be reduced (YES), the process proceeds to step S5. If it is determined that the frequency does not need to be reduced (NO), the process proceeds to step S10.

  It should be noted that the determination of whether or not the frequency of the control signal needs to be reduced is that some determination value is set in advance, and if the absolute value of the integral term is equal to or greater than the determination value, the frequency needs to be reduced. It may be determined, and if the absolute value of the integral term calculated in the current control process is larger than the absolute value of the integral term calculated in the previous control process, it is determined that the frequency needs to be reduced. You may do it.

In step S5, the frequency is reduced from the normal value. The normal value is a frequency value used when there is no influence of magnetic hysteresis or catching on the displacement of the valve body 21.
In step S5, the reduction range from the normal value may be changed according to the absolute value of the integral term. Further, when the frequency is reduced in the control process before the previous time, the frequency may be further reduced or the frequency may be increased after a predetermined control process frequency.

  Next, in step S6, it is determined whether or not the absolute value of the integral term is greater than or equal to a threshold value. If the absolute value of the integral term is equal to or greater than the threshold value (YES), the process proceeds to step S7. If the absolute value of the integral term is less than the threshold value (NO), the process proceeds to step S12.

  In step S7, the count value is increased by 1. This count value corresponds to the time for which the state shown in step S6 (the state in which the absolute value of the integral term is equal to or greater than the threshold) lasts. Next, in step S8, it is determined whether the count value is equal to or greater than a predetermined value. In step S8, it is determined whether or not any characteristic relating to the control of the energization amount Iscv has changed. If the count value is equal to or greater than the predetermined value (YES), it is determined that the characteristic has changed, and the process proceeds to step S9 to correct the characteristic line a. This correction is performed according to the value of the integral value or the value of the rail pressure deviation. If the count value is less than the predetermined value (NO), the flow ends.

  In step S10, the count value is reset to zero. In step S11, the frequency is set to a normal value, and the flow ends. In step S12, the count value is reset to zero. In step S13, the frequency is set to a normal value, and the flow ends.

[Effect of Example 1]
According to the solenoid control device 1 of the first embodiment, when calculating the duty ratio of the control signal, the ECU 8 performs processing based on the integration operation on the rail pressure deviation to calculate the integral term, and calculates the calculated integral term. The frequency of the control signal is varied according to
The absolute value of the integral term increases as the absolute value of the displacement instruction amount deviation such as the rail pressure deviation increases. Therefore, it can be estimated that the larger the absolute value of the integral term, the greater the influence of magnetic hysteresis and catching on the displacement of the valve body 21, and the displacement instruction amount deviation is less likely to be eliminated. Therefore, if the frequency of the control signal is varied according to the integral term, the magnetic hysteresis can be relaxed or the foreign matter causing the catch can be removed according to the degree of the influence of the magnetic hysteresis or the catch. . For this reason, even if the frequency is temporarily lowered, the influence of magnetic hysteresis and catching can be eliminated while suppressing fluctuations in the amplitude and displacement of the energization amount.

Further, the ECU 8 reduces the frequency of the control signal when the absolute value of the integral term increases.
As a result, when the increase in the absolute value of the integral term is caused by magnetic hysteresis or catching, the most appropriate countermeasure (that is, frequency reduction of the control signal) can be taken.

Further, the ECU 8 returns the frequency to the normal value when the absolute value of the integral term becomes smaller than a predetermined threshold after the frequency of the control signal is reduced from the normal value.
As a result, if the absolute value of the integral term decreases, the frequency of the control signal increases, so that fluctuations in the amplitude and displacement of the energization amount can be minimized.

Further, the ECU 8 corrects the characteristic line a indicating the correlation between the energization amount Iscv and the supply amount Q when the absolute value of the integral term is equal to or greater than a predetermined threshold even after the frequency of the control signal is reduced.
If the integral term is not reduced even if the frequency of the control signal is reduced, there is a possibility that some characteristic related to the control of the energization amount is changed, not the displacement instruction amount deviation due to magnetic hysteresis or catching. Therefore, the supply amount Q for the same value of the energization amount Iscv is substantially increased by correcting the characteristic line a. Thereby, even if some characteristic regarding the control of the energization amount is changed, the rail pressure deviation can be converged to zero at an early stage.

[Modification]
According to the solenoid control device 1 of the first embodiment, the driven object is the valve body 21 of the intake metering valve 15, but any driven object that is driven and controlled by manipulating the duty ratio of the control signal. The solenoid control device 1 can be applied to drive control of any driven object. For example, the solenoid control device 1 may be applied to drive control of the control valve of the injector 6.

It is explanatory drawing which shows the structure of a pressure accumulation type fuel-injection apparatus (Example 1). It is explanatory drawing which shows the structure of a solenoid control apparatus (Example 1). (Example 1) which is a characteristic view which shows the correlation with the energization amount and supply amount in an intake metering valve. 3 is a flowchart illustrating a control process by a solenoid control device (first embodiment). (A) is a characteristic diagram which shows the characteristic change by magnetic hysteresis, (b) is a characteristic figure which shows the characteristic change by catching (conventional example). It is a time chart which shows the relationship between the frequency of a control signal, the energization amount to a solenoid coil, and the displacement amount of a to-be-driven object (conventional example).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solenoid control apparatus 2 Accumulated fuel injection apparatus 3 Common rail 5 Fuel supply pump 8 ECU (control means)
15 Suction metering valve 20 Solenoid coil 21 Valve body (driven object)
Q Supply amount (Supply amount by fuel supply pump)
Iscv energization amount (energization amount to solenoid coil)
a Characteristic line (Correlation characteristics between the amount supplied by the fuel supply pump and the amount of current supplied to the solenoid coil)

Claims (5)

A solenoid coil that is energized to generate a magnetic attractive force, a driven object that is driven and displaced by the magnetic attractive force, and a control signal for controlling the energization amount to the solenoid coil are output, and the control signal In a solenoid control device comprising control means for controlling an energization amount to the solenoid coil by operating a duty ratio,
The control means includes
The displacement instruction amount indicating the displacement amount from the reference position of the driven object is grasped, and the duty ratio is calculated based on at least an integration operation with respect to the deviation between the actual value and the target value in the displacement instruction amount. Process,
A solenoid control device that varies a frequency of the control signal in accordance with a calculated value based on the integration operation. The solenoid control device according to claim 1,
The said control means reduces the frequency of the said control signal, when the absolute value of the calculated value based on the said integral operation increases, The solenoid control apparatus characterized by the above-mentioned. In the solenoid control device according to claim 2,
The control means, after reducing the frequency of the control signal, increases the frequency of the control signal when the absolute value of the calculated value based on the integration operation is smaller than a predetermined threshold value. apparatus. In the solenoid control device according to claim 2 or 3,
The control means corrects the characteristic used when calculating the duty ratio when the absolute value of the calculated value based on the integration operation is equal to or greater than a predetermined threshold even after the frequency of the control signal is reduced. A solenoid control device. In the solenoid control device according to claim 4,
The driven object is a valve body of a suction metering valve that forms a part of a fuel supply pump that constitutes an accumulator fuel injection device,
The control means includes
As the displacement instruction amount, grasp the fuel pressure of the common rail constituting the accumulator fuel injection device,
A process based on the integration operation is performed for the deviation between the actual value and the target value in the fuel pressure of the common rail,
Even after reducing the frequency of the control signal, if the absolute value of the calculated value based on the integration operation is equal to or greater than a predetermined threshold, the correlation characteristic between the supply amount by the fuel supply pump and the energization amount to the solenoid coil is A solenoid control device characterized by correcting.

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