JP2007040361A - Solenoid valve drive controlling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set dither frequency capable of sufficiently achieving both of reduction of hysteresis motion of a solenoid control valve and reduction of abrasion of a movable part. <P>SOLUTION: The dither frequency of the solenoid valve 11 of dither driving is determined on the basis of a prescribed map. The map determines the dither frequencies to various applied voltages Va of the solenoid valve 11 in a certain engine rotational frequency Ne=K1, and determines the dither frequencies to the various applied voltages Va of the solenoid valve 11 while applying driving current Ia of the solenoid valve 11 as parameters. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a drive control method and apparatus for a solenoid valve, and more particularly, to a drive control method and apparatus for a solenoid valve that achieves both reduction of hysteresis of the solenoid valve and reduction of wear of a sliding portion.

Conventionally, it is well known that hysteresis is reduced by applying a dither drive that imparts a minute amplitude vibration to a current supplied to an electromagnetic coil constituting an electromagnetic proportional control valve used in various devices. By the way.
As the one that performs dither driving when energizing the electromagnetic coil of the electromagnetic control valve in this way, for example, a configuration in which the dither frequency can be varied according to the control target of the electromagnetic control valve, etc. Various proposals have been made (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-159652 (page 5-7, FIGS. 1 to 5)

By the way, the lower the dither frequency, the higher the effect can be expected to reduce the hysteresis in the electromagnetic control valve. However, the higher the driving frequency is, the higher, in order to reduce the wear of the sliding member due to the electromagnetic force. There are conflicting demands that a reduction effect can be expected. Therefore, the dither frequency is important to select an appropriate frequency that reduces the hysteresis in the operation of the electromagnetic control valve while not sacrificing the effect of friction reduction as much as possible.
The present invention has been made in view of the above circumstances, and provides a drive control method and apparatus for an electromagnetic control valve that can sufficiently satisfy both the reduction of hysteresis operation of the electromagnetic control valve and the reduction of wear of movable parts. To do.

In order to achieve the above object of the present invention, a solenoid valve drive control method according to the present invention comprises:
A solenoid valve drive control method for performing dither drive that generates a minute amplitude in the energization current when energizing the solenoid valve,
The dither frequency in the dither drive is determined and set from a predetermined map or an arithmetic expression according to the driving state of the solenoid valve,
The map or the arithmetic expression is configured based on data obtained in advance according to the driving state of the solenoid valve, and a dither frequency suitable for reducing the hysteresis and sliding portion wear of the solenoid valve.
In order to achieve the above object of the present invention, an accumulator fuel injection control device according to the present invention includes:
An accumulator fuel injection control device for controlling the supply of high-pressure fuel from a common rail to an internal combustion engine of a vehicle,
The accumulator fuel injection control device
The solenoid valve used in the high-pressure pump that pumps high-pressure fuel to the common rail is configured to be dither-driven. Set from the formula,
The map or the arithmetic expression is configured based on data obtained in advance according to the driving state of the solenoid valve, and a dither frequency suitable for reducing the hysteresis and sliding portion wear of the solenoid valve.

According to the present invention, not only the hysteresis of the solenoid valve is reduced, but also the dither frequency suitable for reducing the wear of the sliding portion is selected from the engine speed Ne, the solenoid valve drive current Ia, and the solenoid valve applied voltage Va. Based on the relationship with the above, a map or an arithmetic expression is determined in advance, and the most appropriate dither is determined by a map or an arithmetic expression according to changes in the engine speed Ne, drive current Ia, solenoid valve applied voltage Va, etc. Since the frequency is determined, it is possible to perform dither drive that achieves both hysteresis reduction and sliding part wear reduction according to the drive status of the solenoid valve, thereby improving the reliability of the solenoid valve operation. In addition, the durability can be improved by reducing the wear of the sliding portion, and as a result, the reliability of the entire apparatus can be improved.
In particular, when applied to a device for supplying fuel to an internal combustion engine of a vehicle, such as an electromagnetic valve in a high-pressure pump such as an accumulator fuel injection control device, the reliability of the entire vehicle as well as more stable operation of the engine Can be improved.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 8.
The members and arrangements described below do not limit the present invention and can be variously modified within the scope of the gist of the present invention.
First, a configuration example of a pressure accumulation type fuel injection control device to which a solenoid valve control method according to an embodiment of the present invention is applied will be described with reference to FIG.
The accumulator fuel injection control device S includes a common rail 1 for accumulating high-pressure fuel, a high-pressure pump assembly 2 for supplying high-pressure fuel to the common rail 1, and an N-cylinder diesel engine that uses the high-pressure fuel accumulated in the common rail 1 A plurality of fuel injection valves 3-1 to 3-N for injecting the cylinders 6-1 to 6-N, and a control unit 4 for performing a control operation in the accumulator fuel injection control device S. It is configured as the main component.

The high-pressure pump assembly 2 includes a high-pressure pump main body 2A driven by a diesel engine 5, a fuel metering unit 2B, and an inlet / outlet valve 2C that are assembled together.
Fuel from the fuel tank 7 is supplied to the fuel metering unit 2B by a feed pump 8. In the fuel metering unit 2B, the pressure is adjusted so that the fuel supplied from the feed pump 8 becomes the fuel pressure required by the diesel engine 5, and the fuel is supplied to the inlet / outlet valve 2C. .

  The inlet / outlet valve 2C supplies the fuel sent from the fuel metering unit 2B to the plunger chamber (not shown) of the high-pressure pump assembly 2, and the fuel made high in the plunger chamber flows back into the fuel metering unit 2B. This is supplied to the common rail 1 in such a way that it does not occur. Here, the adjustment of the fuel pressure in the fuel metering unit 2B is performed by opening / closing control of the electromagnetic valve 11 provided in the fuel metering unit 2B.

  The electromagnetic valve 11 is configured to be opened and closed by the control unit 4 so that the fuel pressure in the common rail 1 becomes a pressure corresponding to the required injection amount at that time of the internal combustion engine. In the embodiment, so-called dither drive control is performed during the opening / closing control as will be described later.

  The opening / closing control of the electromagnetic valve 11 is performed, for example, by changing the duty ratio of the pulse signal applied to the electromagnetic valve 11 as is well known. Since the configuration of the electromagnetic valve 11 and the high-pressure pump assembly 2 is known per se, detailed description thereof will be omitted here.

  The control unit 4 includes an actual pressure signal PA from the pressure sensor 9 that detects the actual fuel pressure in the common rail 1, a rotation signal N corresponding to the rotation speed Ne of the diesel engine 10 detected by a rotation sensor (not shown), An operation amount (accelerator opening Acc) of an accelerator pedal (not shown) is input as an input signal. Then, the control unit 4 executes various control programs stored in advance and performs various operation controls based on the input signals as described above. Such a control unit 4 is preferably configured around a known and well-known microcomputer.

  Each of the fuel injection valves 3-1 to 3 -N has an electromagnetic valve for injection control (not shown), and is controlled to be opened and closed independently by a control signal output from the control unit 4. A high pressure fuel is injected into the cylinder by a predetermined amount at a required timing.

FIG. 2 shows a main flowchart showing a procedure of arithmetic processing such as control data necessary for drive control of the electromagnetic valve 11 among a plurality of control programs executed by the control unit 4. This will be described with reference to FIG.
When control by the control unit 4 is started, first, external information such as the engine speed Ne and the accelerator opening Acc necessary for controlling the operation of the solenoid valve 11 is input (step S100 in FIG. 2). reference).
Next, the target injection amount Q to each of the cylinders 6-1 to 6-N and the target common rail pressure P required for the common rail 1 at that time are a predetermined arithmetic expression for calculating the target injection amount, target common rail pressure calculation Are respectively calculated and calculated by a predetermined arithmetic expression for (see step S200 in FIG. 2).

Next, the target injection timing IT is calculated and calculated by a predetermined arithmetic expression for calculating the target injection timing based on data such as the engine speed Ne and the accelerator opening Acc (see step S300 in FIG. 2).
Next, the pumping amount of the high-pressure pump is calculated and calculated by a predetermined calculation formula for that purpose (see step S400 in FIG. 2). The “high pressure pump” in step S400 means the high pressure pump assembly 2.

Next, the opening degree of the electromagnetic valve 11 is calculated and calculated by a predetermined arithmetic expression for calculating the valve opening degree based on the previously determined pumping amount of the high pressure pump (see step S500 in FIG. 2).
Next, the dither frequency Fd, together with the electromagnetic valve drive current Im to be supplied to the electromagnetic valve 11 with respect to the electromagnetic valve opening calculated in step S500, is calculated by a predetermined arithmetic expression and map (details will be described later). Is calculated (see step S600 in FIG. 2). That is, in the embodiment of the present invention, when the solenoid valve 11 is energized and driven, dither driving is performed to give a small amplitude vibration to the energized current. The dither frequency is calculated as described later.

  Finally, the injector energization period ET, that is, the energization period to the fuel injection valves 3-1 to 3-N is calculated and calculated by a predetermined arithmetic expression for that purpose, and is required for operation control by the control unit. The calculation processing of various control data is terminated. After the control data calculation process is completed, various operation controls based on the calculated control data are executed in a main routine (not shown).

Next, a first example of a more specific procedure for calculating the dither frequency Fd will be described with reference to FIGS.
When the process is started, first, the engine speed Ne is input (see step S602 in FIG. 3). The input of the engine speed Ne is previously read in step S100, and the data stored in a predetermined storage area (not shown) in the control unit 4 may be taken into this subroutine processing. Any of these may be read into the control unit 4 anew.

Next, the drive current Ia is input (see step S604 in FIG. 3). Here, the drive current Ia is a current that actually flows through the electromagnetic valve 11, and is fed back from, for example, a drive circuit (not shown) of the electromagnetic valve 11 provided in the control unit 4.
Next, the actual applied voltage to the solenoid valve 11, that is, the solenoid valve applied voltage Va is input (see step S606 in FIG. 3). The input of the solenoid valve applied voltage Va is also fed back from a drive circuit (not shown) of the solenoid valve 43 as in the case of the drive current ia.

Then, the dither frequency based on the solenoid valve applied voltage Va is obtained by map calculation using the engine speed Ne, the drive current Ia, and the solenoid valve applied voltage Va input as described above (FIG. 3). Step S608).
That is, in the first example of the calculation process of the dither frequency, as shown in an example in FIG. 6, an appropriate dither frequency for various values of the solenoid valve applied voltage Va at a certain engine speed Ne = K1. In the control unit 4, the relationship is mapped or computed using the drive current Ia as a parameter. For convenience, the map shown in FIG. 6 will be referred to as the basic map in the first example, and the dither frequency obtained from this basic map will be referred to as “dither basic frequency F01” for convenience.

  What dither frequency is appropriate for various values of the solenoid valve applied voltage Va depends on differences in individual characteristics of the solenoid valve 11, differences in characteristics of the entire device, etc., and is uniquely determined. Therefore, it is preferable to be determined based on simulation, actual measurement data, or the like. Unlike the conventional case, the dither frequency in the embodiment of the present invention is not just a value selected from the viewpoint of reducing the hysteresis of the solenoid valve 11, but at the same time as a value suitable for reducing wear of an appropriate sliding portion. Thus, the frequency selected by simulation or the like is determined by mapping or an arithmetic expression. This also applies to other examples shown in FIG.

  According to the example of the map showing the correlation between the solenoid valve applied voltage Va and the dither frequency shown in FIG. 6, the dither frequency gradually increases as the solenoid valve applied voltage Va rises, and the rate of increase is determined by the drive current. It becomes larger as Ia becomes larger.

  FIG. 6 shows an example of a map showing the correlation between the solenoid valve applied voltage Va and the dither frequency using the driving current Ia at a certain engine speed Ne = K1 as a parameter. A similar correlation map for the number Ne is preferably obtained by simulation or the like and stored in the control unit 4 as described above. If the map cannot be obtained directly from the map, that is, if there is no map of the corresponding engine speed Ne, or if the corresponding drive current Ia is not in the map, it may be obtained by so-called interpolation calculation. Note that the interpolation calculation itself is a well-known technique in numerical processing and the like, so detailed description thereof will be omitted here.

  In addition, instead of storing the above-described map, an arithmetic expression of the map is stored, and the input engine speed Ne, drive current Ia, and solenoid valve applied voltage Va are substituted into the arithmetic expression, and dither is performed. The frequency may be calculated.

Next, a second example of the procedure for calculating the dither frequency Fd will be described with reference to FIGS.
First, in the second calculation processing example, step S602A, step S604A, and step S606A correspond to the processing of step S602, step S604, and step S606 in FIG. 2, respectively, and basically have the same processing contents. Since there is, the description here will be omitted.

In step S608A, a dither frequency based on the drive current Ia is obtained by map calculation from the engine speed Ne, the drive current Ia, and the solenoid valve applied voltage Va input by the processes in steps S602A to S606A ( (See step S608 in FIG. 3).
That is, in this second example, as shown in FIG. 7, an appropriate dither frequency relationship with various values of the drive current Ia at a certain engine speed Ne = K1 indicates that the solenoid valve applied voltage is The control unit 4 stores a map or arithmetic expression using Va as a parameter. For convenience, the map shown in FIG. 7 is a basic map in the second example, and a dither frequency obtained from the basic map is referred to as “dither basic frequency F02” for convenience.

What dither frequency is appropriate for various values of the drive current Ia differs depending on individual characteristics of the electromagnetic valve 11 or differences in characteristics of the entire device, and is not uniquely determined. Therefore, it is preferable to be determined based on simulation, actual measurement data, or the like.
The example of the map showing the correlation between the driving current Ia and the dither frequency shown in FIG. 7 includes a singular point in the change of the dither frequency with respect to the driving current Ia.

That is, the dither frequency with respect to the drive current Ia basically increases gradually as the drive current Ia rises, and the rate of increase increases as the drive current Ia increases.
By the way, the electromagnetic valve 11 may be in a state showing a so-called negative resistance depending on its driving state. In the embodiment of the present invention, the relationship between the drive current Ia and the dither frequency in such a state is also included in the map, and is a portion indicated by symbol a in FIG.

  In FIG. 7, the change characteristics of the drive current Ia and the dither frequency in the part marked with a symbol a show such a change that the characteristic line is convex above the characteristic line. Yes. In other words, in the vicinity indicated by the symbol a, the dither frequency increases rapidly as the drive current Ia increases, but the dither frequency decreases rapidly after a certain drive current Ia. It shows that change.

  As described in FIG. 6, it is preferable to obtain a correlation map similar to that in FIG. 7 for a plurality of engine speeds Ne by simulation or the like as described above and store it in the control unit 4. If the map cannot be obtained directly from the map, that is, if there is no map of the corresponding engine speed Ne, or if the corresponding drive current Ia is not in the map, it may be obtained by so-called interpolation calculation.

  In addition, instead of storing the above-described map, the map is converted into an arithmetic expression, and the input engine speed Ne, drive current Ia, and solenoid valve applied voltage Va are substituted into the arithmetic expression. The dither frequency may be calculated.

Next, a third example of the procedure for calculating the dither frequency Fd will be described with reference to FIGS.
First, in this third calculation processing example, step S602B, step S604B, and step S606B correspond to the processing of step S602, step S604, and step S606 in FIG. 2, respectively, and basically have the same processing contents. Since there is, the description here will be omitted.

In step 608B, a dither frequency based on the engine speed Ne is obtained by map calculation from the engine speed Ne, the drive current Ia, and the solenoid valve applied voltage Va input by the processes in steps S602B to S606B. (See step S608B in FIG. 5).
That is, in this third example, as shown in an example in FIG. 8, at a certain solenoid valve applied voltage Va = C1, the relationship of an appropriate dither frequency to various values of the engine speed Ne is the target injection. The control unit 4 stores a map or arithmetic expression using the quantity Q as a parameter. For convenience, the map shown in FIG. 8 is the basic map in the third example, and the dither frequency obtained from this basic map is referred to as “dither basic frequency F03” for convenience.

What dither frequency is appropriate for various values of the engine speed Ne differs depending on differences in individual characteristics of the solenoid valve 11, differences in characteristics of the entire device, and the like. Therefore, it is preferable that the value is determined based on simulation, actual measurement data, or the like.
According to the example of the map showing the correlation between the engine speed Ne and the dither frequency shown in FIG. 8, the dither frequency gradually increases as the engine speed Ne increases, and the rate of increase is determined by the target injection amount Q. It becomes larger as becomes larger.

  As described in FIG. 6, it is preferable that a correlation map similar to that in FIG. 8 is obtained by simulation as described above for a plurality of solenoid valve applied voltages Va and stored in the control unit 4. If the map cannot be obtained directly from the map, that is, if there is no map of the corresponding solenoid valve applied voltage Va, or if the corresponding engine speed Ne is not on the map, it may be obtained by so-called interpolation calculation. Good.

  As described above, in the embodiment of the present invention, not only the hysteresis in the solenoid valve 11 is reduced, but also the dither frequency appropriate for reducing the wear of the movable part of the solenoid valve 11 is determined by the engine speed Ne and the drive. As determined by the relationship with the current Ia and the solenoid valve applied voltage Va, the engine speed Ne and the drive at that time are calculated using a map or an arithmetic expression created based on the results of experiments and simulations in advance. It is determined with respect to the current Ia and the solenoid valve applied voltage Va.

  In the embodiment of the present invention, the determination of the dither frequency has been described on the assumption that any one of the procedures described in FIG. 3, FIG. 4 and FIG. It is not necessary to be limited to such a form. That is, for example, the procedure shown in FIG. 3, FIG. 4 and FIG. 5 may be switched and executed as necessary under predetermined conditions, and at that time, the three procedures may be switched. However, the present invention is not limited to this, and switching between two arbitrarily selected procedures may be used.

It is a block diagram which shows the structural example of the pressure accumulation type fuel-injection control apparatus with which the solenoid valve control method in embodiment of this invention is applied. It is a flowchart which shows the whole procedure of the calculation process of the control data used for the drive control of the solenoid valve performed by the control unit which comprises the pressure accumulation type fuel injection apparatus shown by FIG. It is a flowchart which shows the procedure in the 1st example of the calculation process of a dither frequency. It is a flowchart which shows the procedure in the 2nd example of the calculation process of a dither frequency. It is a flowchart which shows the procedure in the 3rd example of the calculation process of a dither frequency. It is a characteristic diagram which shows an example of the map which shows the relationship of the dither frequency with respect to the solenoid valve applied voltage used for the setting of the dither frequency in embodiment of this invention. It is a characteristic diagram which shows an example of the map which shows the relationship of the dither frequency with respect to the drive current used for the setting of the dither frequency in embodiment of this invention. It is a characteristic diagram which shows an example of the map which shows the relationship of the dither frequency with respect to the engine speed used for the setting of the dither frequency in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Common rail 2 ... High pressure pump assembly 3-1 to 3-N ... Fuel injection control valve 4 ... Control unit 5 ... Diesel engine 11 ... Solenoid valve

Claims (15)

A solenoid valve drive control method for performing dither drive that generates a minute amplitude in the energization current when energizing the solenoid valve,
The dither frequency in the dither drive is determined and set from a predetermined map or an arithmetic expression according to the driving state of the solenoid valve,
The map or the calculation formula is configured based on data obtained in advance according to the driving state of the solenoid valve, a dither frequency suitable for reducing hysteresis and sliding portion wear of the solenoid valve. A solenoid valve drive control method. The solenoid valve is used in a high-pressure pump that constitutes an accumulator fuel injection control device that controls fuel injection into an internal combustion engine, and controls the flow rate of high-pressure fuel delivered from the high-pressure pump by opening and closing. And
2. The solenoid valve drive control method according to claim 1, wherein the drive state of the solenoid valve is based on at least the rotational speed of the internal combustion engine, the drive current of the solenoid valve, and the applied voltage of the solenoid valve.    The map or the calculation formula determines the dither frequency for various applied voltages of the solenoid valve at a predetermined engine speed, and the dither frequency for the various applied voltages of the solenoid valve is obtained using the driving current of the solenoid valve as a parameter. 3. The electromagnetic valve drive control method according to claim 2, wherein the electromagnetic valve drive control method is configured as described above.   The map or calculation formula determines the dither frequency for various drive currents of the solenoid valve at a predetermined engine speed, and the dither frequency for various drive currents of the solenoid valve is obtained using the applied voltage of the solenoid valve as a parameter. 3. The electromagnetic valve drive control method according to claim 2, wherein the electromagnetic valve drive control method is configured as described above.   The map or the calculation formula defines dither frequencies for various engine speeds at a predetermined applied voltage of the solenoid valve, and is configured to obtain dither frequencies for various engine speeds using the target injection amount as a parameter. The electromagnetic valve drive control method according to claim 2, wherein:   The electromagnetic valve drive control method according to claim 2, wherein a plurality of different types of maps or arithmetic expressions are provided and selectively used according to conditions.   The electromagnetic valve drive control method according to claim 6, wherein the plurality of different types of maps or arithmetic expressions include the maps or arithmetic expressions according to claim 3 and claim 4.   The electromagnetic valve drive control method according to claim 6, wherein the plurality of different types of maps or arithmetic expressions include the maps or arithmetic expressions according to claim 3 and claim 5.   The electromagnetic valve drive control method according to claim 6, wherein the plurality of different types of maps or arithmetic expressions include the maps or arithmetic expressions according to claim 4 and claim 5.   7. The electromagnetic valve drive control method according to claim 6, wherein the plurality of different types of maps or arithmetic expressions include the maps or arithmetic expressions according to claim 3, 4 and 5. An accumulator fuel injection control device for controlling the supply of high-pressure fuel from a common rail to an internal combustion engine of a vehicle,
The accumulator fuel injection control device
The solenoid valve used in the high-pressure pump that pumps high-pressure fuel to the common rail is configured to be dither-driven. Set from the formula,
The map or the calculation formula is configured based on data obtained in advance according to the driving state of the solenoid valve, and a dither frequency suitable for reducing hysteresis and sliding part wear of the solenoid valve. An accumulator fuel injection control device.   12. The accumulator fuel injection control device according to claim 11, wherein the drive state of the solenoid valve is based on at least the rotational speed of the internal combustion engine, the drive current of the solenoid valve, and the applied voltage of the solenoid valve.   The map or the calculation formula determines the dither frequency for various applied voltages of the solenoid valve at a predetermined engine speed, and the dither frequency for the various applied voltages of the solenoid valve is obtained using the driving current of the solenoid valve as a parameter. The pressure-accumulation fuel injection control device according to claim 12, which is configured as described above.   The map or calculation formula determines the dither frequency for various drive currents of the solenoid valve at a predetermined engine speed, and the dither frequency for various drive currents of the solenoid valve is obtained using the applied voltage of the solenoid valve as a parameter. The pressure-accumulation fuel injection control device according to claim 12, which is configured as described above.   The map or the calculation formula defines dither frequencies for various engine speeds at a predetermined applied voltage of the solenoid valve, and is configured to obtain dither frequencies for various engine speeds using the target injection amount as a parameter. The accumulator fuel injection control device according to claim 12, wherein

Images