JPH1047169A - Engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable correct feedback control with compatibility of responsiveness and stability by calculating the target position and the driving direction of a valve element of a control valve such as a solenoid valve arranged in an EGR device, and calculating the drive quantity of the valve element from the target position and the driving direction to control the drive of the valve element. SOLUTION: In a system where a part of the exhaust gas is recirculated to the air intake system through an EGR valve 10 (control valve), a control unit 20 to control a solenoid valve 10 is provided with a target position calculating means 35 to operate the target position of the solenoid valve 10 so as to obtain the desired EGR recirculation ratio from the engine speed 24a, the sucked air volume 25a and the cooling water temperature 26a. In a driving direction operating means 36, after the changing direction (driving direction) of the target position is calculated, the drive quantity is calculated by a drive quantity calculating means 37. The drive duty is operated based on the valve opening side characteristic curve when the valve is judged to be driven to the opening side, or based on the valve closing side characteristic curve when the valve is judged to be driven in the closing side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a control valve such as a solenoid valve, and more particularly, to an EGR for an automobile engine or the like.
The present invention relates to an engine control device suitable for controlling an electromagnetic valve and the like provided in the device.

[0002]

2. Description of the Related Art It has been conventionally known to incorporate an exhaust gas recirculation (hereinafter, referred to as EGR) device into an engine of an automobile or the like in order to purify exhaust gas and improve fuel efficiency. In recent years, in order to further improve fuel efficiency, it has been required to achieve a higher rate of exhaust gas recirculation (EGR rate) than before, and when the EGR rate is increased, the operating state of the engine changes suddenly. Also, it is necessary to control the engine to an appropriate EGR rate by following a change in the EGR limit.

[0003] For this reason, normally, in order to apply to the control of the EGR rate, an electromagnetic valve type EG driven in the exhaust gas recirculation line based on a signal from an engine control device.
There has been proposed an EGR valve in which an R valve (control valve) is disposed and a lift sensor for detecting a valve body position of the EGR valve is provided in the EGR valve in order to precisely control the opening degree of the EGR valve. If the EGR valve with the lift sensor is used, feedback control for correcting the valve drive amount based on the deviation between the target valve position and the output of the lift sensor can be performed, and the feedback control can precisely control the opening of the EGR valve. Can be.

[0004]

In the case of the solenoid valve type EGR valve, when the hysteresis of the opening (lift amount) of the valve body with respect to the drive duty is large, even if the normal feedback control is applied, the feedback is not required. When the control gain is small, the response speed tends to be slow,
If the gain of the feedback control is excessive, there is a problem that the lift amount is not stable due to overshoot, and there is a problem that it is difficult to set an optimal feedback control gain.

[0005] Further, when the characteristic including the hysteresis of the lift amount with respect to the drive duty amount for driving the EGR valve changes due to the contamination component in the exhaust gas adhering to the sliding portion or the like in the EGR valve, the feedback is performed. There is a problem that necessary controllability cannot be ensured by control alone. If the obstruction of the valve body operation due to such contamination of the EGR valve becomes remarkable, the sliding portion of the EGR valve will adhere to the non-sliding portion, and the EGR valve will be in a failure state. The failure state can be diagnosed by detecting that the relationship between the drive duty amount and the lift amount is equal to or more than a predetermined value. However, it is not possible to detect a failure such as a decrease in the response speed due to the adhesion of dirt as described above. Have difficulty.

Further, the EGR valve is in a state in which the upstream side of the valve body is exposed to the exhaust gas pressure and the downstream side is exposed to the intake pipe pressure, and the pressure applied to the valve body varies depending on the operating state. The balance may change, and the required drive duty amount for the same opening may change. In such a case, the control of the EGR valve becomes more difficult because the width of the hysteresis is widened.

Further, as described above, if the response of the EGR valve is delayed or the lift amount is not stable, if the misfire limit EGR rate changes suddenly, for example, during rapid deceleration, the EGR rate becomes excessive. Therefore, there is a problem that a misfire occurs due to the occurrence of an engine, adversely affecting the exhaust gas, and a change in the output torque of the engine due to a change in the EGR rate.

The present invention has been made in view of such a problem, and an object of the present invention is to eliminate the effect of hysteresis of a valve opening (lift amount) on a drive duty of an EGR valve of an engine. Accurate feedback control compatible with both responsiveness and stability, and the EG
An object of the present invention is to provide an engine control device capable of detecting a failure of an R valve.

[0009]

In order to achieve the above object,
The engine control device according to the present invention includes a control valve, a unit that calculates a target position of a valve body of the control valve, and a unit that calculates a driving direction of the valve body. The driving amount of the valve element is calculated from the driving amount, and the driving of the valve element is controlled based on the driving amount, and the driving direction is calculated based on the direction of change of the target position.

In another specific aspect of the engine control device according to the present invention, the control device includes a control valve, means for detecting a valve body position of the control valve, and an engine operating state. Means for calculating a target position of the valve element, means for calculating a basic drive amount of the valve element from the target position, means for calculating a correction amount based on a deviation between the target position and the detected position of the valve element, Means for calculating a driving direction, means for calculating a driving amount from the basic driving amount and the correction amount, and means for driving the control valve based on the driving amount, wherein the driving amount is calculated based on the target position. The basic drive amount is controlled so that the control amount varies depending on the drive direction.
The control valve is an electromagnetic valve, and is provided in an EGR device.

Further, the engine control device according to the present invention includes means for diagnosing a failure of the control valve, wherein the failure diagnosing means has a deviation between a target position and a detected position of the valve body which is equal to or greater than a predetermined value, and When the predetermined value state continues for a predetermined time or more, the failure of the control valve is diagnosed, and the engine control device includes a learning unit, and the learning unit determines a driving direction of the valve body based on the correction amount. A learning amount is separately calculated, and a failure of the control valve is diagnosed by comparing the learning amount with a predetermined value set in advance, and the learning unit sets an update direction of the learning value of the correction amount according to a driving direction. It is characterized by regulation control.

Furthermore, the engine control device of the present invention
The present invention is characterized in that there is provided a means for correcting the basic drive amount calculated based on the target position using the pressure or the differential pressure parameter on each side of the upstream and downstream of the valve element. The engine control device according to the present invention configured as described above calculates the basic drive amount by setting the target position of the valve body from the operating state of the engine, detects the actual valve body position, and detects the detected position. And the drive amount is corrected based on the deviation between the target position and the target position, and the drive direction to the target position is calculated to calculate the drive amount of the valve body according to the drive direction. In addition, problems such as instability of the lift amount due to overshoot are eliminated.

That is, a target position is set from the operating state of the engine, and the valve is opened when the driving direction calculated from the difference between the target position and the detected position is the valve opening side, and is closed when the driving direction is the valve closing side. By calculating the basic control amount based on the characteristic line on the side, it is possible to obtain the basic drive amount without the influence of each hysteresis, the deviation between the target position and the lift amount is reduced, and the feedback control amount can be reduced. Therefore, a control that simultaneously satisfies the responsiveness and stability of the control valve is provided.

[0014] In addition, the fixing failure due to contamination of the control valve or the like is performed by calculating a deviation between the target position and the detected position, and detecting that the state in which the deviation is a predetermined value or more has continued for a predetermined time or more. This makes it possible to diagnose the sticking failure and the like.
That is, by detecting that a state where the lift amount is small despite giving a sufficiently large drive duty or a state where the lift amount is large despite the drive duty is small has continued for a predetermined time or more, Diagnosis is possible for sticking.

Further, the characteristic change of the control valve due to contamination or the like of the control valve can be obtained by learning the correction amount for each driving direction.
By regulating the update direction of the correction amount learning value in accordance with the drive direction, the update direction is absorbed, and control can be performed in the same manner as a valve having normal characteristics.
That is, in general, the duty for obtaining the same lift amount increases on the valve opening side, and the duty for closing to the same lift amount decreases on the valve closing operation side. By learning in the direction to increase the basic drive amount with respect to the target position on the valve opening side and in the direction to decrease the basic drive amount with respect to the valve closing side, it is possible to obtain an appropriate basic drive amount including a characteristic change. By restricting the learning direction, it is possible to prevent erroneous learning when the response speed of the valve element is high due to the influence of vibration or pressure.

Further, abnormal decrease in response speed due to contamination of the control valve or the like can be diagnosed by comparing the learning amount with a predetermined value set in advance, and the pressure applied to the valve body of the control valve can be diagnosed. The effect of the correction of the basic control amount calculated based on the target position by the parameters of the pressure or differential pressure on each side of the upstream and downstream of the valve body to absorb the delay of the response speed based on the dirt. Normal response speed. That is, the influence of the pressure applied to the valve body is, for example, when the intake pipe pressure is low, if the valve body receives a force in the closing direction, the required duty is large on the valve opening side with respect to the same target position, Side is smaller. By correcting the basic drive amount in advance based on the output value of the intake pipe internal pressure sensor or the intake pipe pressure obtained from the intake air amount and the engine speed, a precise basic drive amount can be obtained. Control that simultaneously satisfies the responsiveness and stability of

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an engine control device according to the present invention will be described in detail with reference to the drawings. FIG.
1 shows the overall configuration of an engine system including the engine control device of the present embodiment. Each cylinder 7 of the engine body 1 includes a piston 1a, a cylinder 1b, and a combustion chamber 1
c, and an intake section 1d and an exhaust section 1e are arranged above the combustion chamber 1c.

The intake air flows in from the air cleaner 2,
The air is supplied from the collector box 5 of the intake manifold via the air flow meter 3 and the throttle body 4 to the respective cylinders 7 of the engine body 1 via the branch 6. Fuel is supplied from a fuel injection valve 8. Here, a part of the exhaust gas discharged from the engine body 1 flows from the exhaust part 1 d through the EGR passage 9 to the collector box 5 via the EGR valve (control valve) 10. EGR valve 10
Are driven by a signal from the control unit 20.

The control unit 20 mainly includes a CPU
The engine is operated by a rotation sensor 24, an intake air amount sensor 25, a water temperature sensor 26, a throttle opening sensor 27, and a lambda sensor 28 for detecting oxygen concentration in exhaust gas. And the like, and the calculation is performed by taking an output signal based on the detection into the control unit 20 via the interface 21. Control unit 20
Performs a calculation based on information from each of the sensors, and based on the calculation, the drive pulse width of the fuel injection valve 8, the timing of energizing the ignition coil 29, the idle auxiliary air amount control valve 3
Control 0 etc.

In this embodiment, the EGR valve 10
Is controlled by a duty signal output from the control unit 20, the control by the drive current or the drive of the EGR valve 10 is used as a stepper motor, and the stepper motor is output from the control unit 20. It may be driven based on a pulse signal.

An example of the EGR valve 10 is shown in FIG.
And a control unit 20 is electrically connected to the control unit 20 via a connector 11. The connector 11 has an input to the coil 12 and an output terminal from the lift sensor 16. The valve element 14 is connected to the plunger 13 via a rod 15 and is urged by a spring 17 toward the valve closing side.

When the coil 12 is energized, the plunger 13 is magnetically attracted to the valve-opening side, and the attraction force and spring force, the frictional force of the movable portion, and the force due to the upstream and downstream pressure difference at the valve element 14. Stop at the point where the balance etc. are balanced. The magnetic attractive force is adjusted by controlling the duty ratio of the duty signal or the current to obtain a desired valve opening.

FIG. 3 shows a circuit for controlling the EGR valve 10. The opening signal of the EGR valve 10 is expressed by the following equation.
Although output from the lift sensor 16, the lift sensor 16
Is the control unit 2 at one end of the sliding resistance
A reference voltage is applied from 0 and the other end is grounded.
A reference voltage according to the position of the slider that moves in conjunction with
Move between ground potentials. At this time, the reference voltage and the ground of the lift sensor 16 are shared with the analog / digital converter of the control unit 20. The digital information converted by the analog / digital converter is taken into the CPU 22 as an output voltage of the lift sensor 16.

FIG. 4 shows an example of the hysteresis characteristic (valve opening direction 31, valve closing direction 32) of the EGR valve 10 between the valve opening direction and the valve closing direction. FIG. 4 shows the drive duty of the EGR valve 10 on the horizontal axis, and the output voltage of the lift sensor 16 on the vertical axis. The output of the lift sensor when fully closed is 0.5 V, and when fully open is 4.5 V. Yes, 60% in the valve opening direction with respect to the opening degree of the lift sensor output 3V,
It has a hysteresis characteristic such that the drive duty is 40% in the valve closing direction.

For example, when an opening corresponding to the lift sensor output of 3.0 V is set as the target position in the specific operation state, if the state before that is a position smaller than the lift sensor output of 3.0 V, 60% By applying the duty, the valve moves in the valve opening direction, and the opening degree is equivalent to the output of the lift sensor 3.0 V. On the other hand, if the previous state is a position larger than the lift sensor output 3.0 V, the valve moves in the valve closing direction by giving a duty of 40%, and the opening degree is equivalent to the lift sensor output 3.0 V. 60% of these
Alternatively, 40% corresponds to the basic control amount. However, since this characteristic varies due to the effects of manufacturing variations, deterioration, pressure, vibration, etc. of the EGR valve 10, a desired valve opening can be obtained by further performing feedback control so that the lift sensor output matches the target value. Can be.

FIG. 5 shows the hysteresis characteristics when the hysteresis is larger than that set in advance due to manufacturing variations of the EGR valve 10 or use deterioration. Here, when the basic control amount is set along the characteristic line of FIG.
%, The correction amount of -8% on the valve closing side 34 must be added to the drive duty. This state is corrected by applying the feedback control, but the controllability can be improved by using the value as a learning value. In the learning, by allowing the learning only in the direction in which the hysteresis becomes large, when the equilibrium state of the control is inside the hysteresis (for example, point A in FIG. 5).
Erroneous learning can be prevented.

The means for detecting a sticking failure of the valve element 14 using the hysteresis shown in FIG. 4 will be described. For example, 6
When driving at 0% duty, lift sensor 1
It is normal that the output of No. 6 is at least 3.0 V, but if the output of the lift sensor 16 continues to be 1.0 V or less despite being driven at a duty of 60%, It can be determined that the possibility that the valve body 14 is fixed at a position of 1.0 V or less is large. Conversely, when the motor is driven at a duty of 40%, the output of the lift sensor 16 should not exceed 3.0 V.
If the state of V or more continues, it can be determined that there is a possibility that the valve body 14 is stuck in an open state. These methods make it possible to diagnose the sticking failure of the valve element 14. The continuation determination time (diagnosis delay time) for this diagnosis is desirably determined in consideration of the responsiveness of the EGR valve 10.

Next, detection of a state in which the friction of the movable portion becomes excessive due to adhesion of dirt to the valve body 14 and the rod 15 and the hysteresis and the response speed are out of the allowable range will be described. As described above, the expansion of the hysteresis is absorbed by the learning, but a failure in which the hysteresis is excessive can be diagnosed when the learning value exceeds a predetermined value. In addition, even when the response speed is out of the allowable range and is slow, but is not enough to be detected by the above-described stuck-at fault diagnosis, the learning value is updated by temporarily increasing the feedback control correction value. By comparing the learning value with a predetermined value, it is possible to diagnose a failure in which the response speed is slow.

FIG. 6 is a basic control block diagram of an engine control device for controlling the solenoid valve 10 according to the present embodiment. The control unit 20 counts pulses taken from a rotation speed sensor 24 attached to the engine 1 within a predetermined time by a rotation speed calculation means (not shown), and thereby calculates the engine rotation speed 24 a and the intake air amount sensor 25. A / D conversion of output voltage allows 25
a is converted from an output voltage from the cooling water temperature sensor 26 to A / D, thereby taking in the cooling water temperature 26a, and inputting it to the target position calculating means 35. The target position calculating means 35 calculates the engine speed 24a, the intake air amount 25a,
The target position (opening) 35a of the solenoid valve 10 is calculated so that a desired EGR recirculation rate is obtained from the cooling water temperature 26a.

The target position 35a is calculated at predetermined time intervals, and the control unit 20 sets the target position 35a.
The driving direction calculating means 36 includes means for temporarily storing the calculated value of a (not shown), and the driving direction calculating means 36 calculates the direction of change of the target position based on the difference between the stored previous target position and the currently calculated target position 35a. (Drive direction (valve opening direction or valve closing direction)) is calculated.

The drive amount calculating means 37 is provided with the target position 35.
The driving amount 37a is calculated based on a and the target position change direction (driving direction). At this time, when it is determined that the driving is to the valve opening side, for example, the driving duty with respect to the target position is calculated based on the valve opening side characteristic curve 31 in FIG. 4, and conversely, it is determined that the driving is to the valve closing side. In this case, the drive duty is calculated based on the characteristic curve shown in FIG.

The drive means 39 calculates the calculated drive amount 37a.
The solenoid valve 10 is driven on the basis of. The drive by the drive means 39 is a control drive in consideration of the hysteresis of the electromagnetic valve 10, and enables precise EGR recirculation amount control, enabling a large amount of EGR without impairing the drivability of the vehicle.
Purification of exhaust gas and fuel efficiency can be improved. FIG.
Is a control block diagram showing feedback control, feedback correction learning control, differential pressure correction control, and self-diagnosis based on the output signal of the valve body position sensor 16 in addition to the basic control block diagram of FIG. Is shown.

The control unit 20 counts the number of pulses taken from the rotation speed sensor 24 attached to the engine 1 within a predetermined time by the rotation speed calculating means 43, and determines the engine rotation speed 24a. The output voltage is digitally converted by the A / D converter 41 and is calculated by the intake air amount calculation means 44, so that the intake air amount 25a is
The output voltage from the cooling water temperature sensor 26 is digitally converted by the A / D converter 42 and calculated by the cooling water temperature calculating means 45, thereby taking in the cooling water temperature 26a and inputting it to the target position calculating means 47. Target position 47a of the valve body of the valve 10
Is calculated, and the engine speed 24a and the intake air amount 25a are input to the solenoid valve upstream and downstream differential pressure calculating means 46.

On the other hand, the valve body position sensor 16 detects the valve body position 16.
The output voltage detected as a is digitized by the A / D converter 40 and output. The output signal is input to the F / B correction amount calculating means (correction amount calculating means) 50, and the signal of the target position 47a is also input to the F / B correction amount calculating means 50. In the F / B correction amount calculating means 50, the target position 4
An F / B correction amount is calculated from the difference between 7a and the valve element position 16a.

The driving direction calculating means 49 calculates the driving direction based on the sign of the valve body position 16a detected by the valve body position sensor 16, and the basic driving amount calculating means 52 calculates the driving direction from the target position 47a and the driving direction. A basic drive amount in consideration of the hysteresis of the solenoid valve 10 is calculated. The solenoid valve valve upstream / downstream differential pressure calculating means 46 calculates the difference between the exhaust pressure and the intake pipe negative pressure by calculating the intake pipe negative pressure downstream of the solenoid valve 10 from the intake air amount 25 and the engine speed 24a. The differential pressure correction amount calculating means 48 calculates a correction amount for correcting the force applied to the valve body of the solenoid valve 10 based on the calculated upstream / downstream differential pressure. The differential pressure correction amount is added to the basic drive amount, and the F / B calculated by the F / B correction amount calculation unit 50 is calculated.
The correction amount is also added to the basic drive amount, and the feedback control (F / B control) enables more precise EGR control.

The learning value updating means 51 performs a filter operation having a predetermined gain on the F / B correction amount calculated by the F / B correction amount calculating means 50, and is stored in the learning value storage means 53. The learning value is sequentially updated. At this time, the learning value for each direction (valve opening side, valve closing side) is updated in accordance with the driving direction calculated by the driving direction calculation means 49. The learning value according to the driving direction is selected according to the driving direction, added to the basic driving amount, and output.

As described above, by adding the F / B correction and the differential pressure correction to the basic drive amount and the learning value having different characteristics depending on the drive direction, and driving the solenoid valve, the characteristics including hysteresis and deterioration of the solenoid valve are obtained. It is possible to realize EGR control that can absorb variations and characteristic changes due to the differential pressure between the upstream and downstream of the valve element. This makes it possible to perform a large amount of EGR without impairing the operability of the vehicle, thereby purifying exhaust gas and improving fuel efficiency. it can.

The self-diagnosis means 54 determines that the F / B correction amount calculated by the F / B correction amount calculation means 50 exceeds a predetermined value, and the state where the F / B correction amount exceeds the predetermined value continues for a predetermined time or more. Or if the learning value is equal to or greater than a predetermined value, a diagnosis of a failure or the like is made and the switch 56
Is operated to correct the drive amount to the fail-safe value stored in the fail-safe value storage means 55, and
Adjust the valve body position of 0.

FIG. 8 is a control flowchart of the control system of the solenoid valve in the engine control device of the present embodiment, and particularly shows a control routine for driving the solenoid valve. In step 61, the valve target position 47a is calculated, and the routine proceeds to step 62. In step 62, the previously calculated valve target position is updated to the calculated new valve target position 47a. In step 63, the basic drive amount calculation means 52 calculates a basic duty for driving the solenoid valve.

A specific flowchart for calculating the basic duty for driving the solenoid valve is as shown in FIG. That is, it is determined whether or not the target position newly calculated in step 71 of FIG. 9 is equal to the previously calculated target position.
If they are equal, the process returns with no change in the target position.
If they are not equal, the process proceeds to step 72,
In step 2, it is determined whether the newly calculated target position is larger than the previously calculated target position. If the newly calculated target position is larger than the previously calculated target position, it means that the valve body has moved in the valve opening direction, so the process proceeds to step 73,
In step 73, the duty of the basic drive amount is calculated in consideration of the hysteresis of the solenoid valve in the valve opening direction. Also,
If the newly calculated target position is smaller than the previously calculated target position, it means that the valve element is moving in the valve closing direction, so the process proceeds to step 74, where the hysteresis of the solenoid valve in the valve closing direction is determined. Is calculated in consideration of the basic drive amount. In step 75, the previously calculated target position is changed to the currently calculated target position, and the routine returns.

At step 64 in FIG. 8, the differential pressure correction amount calculating means 48 calculates the differential pressure correction amount based on the differential pressure upstream and downstream of the valve body of the solenoid valve 10, and the routine proceeds to step 65. Step 65
Then, the valve body position 16 based on the detection of the valve body position sensor 16
A valve position feedback correction amount is calculated based on a comparison between the variable a and the target position 47a of the valve element. A specific flowchart for calculating the valve position feedback correction amount,
This is shown in FIG. Steps 81 and 82 in FIG.
Then, the valve body position (valve position) of the solenoid valve 10 is detected by the valve body position sensor 16 and converted into a digital signal. In step 83, the detected valve position is compared with the target position, and the difference (Δ
PS), and then proceeds to step 84. In step 84, the absolute value of the difference (ΔPS) is compared with a specific constant (PSLIM), and the absolute value of the difference (ΔPS) is compared with the specific constant (PSLIM).
If it is smaller, it is determined that the positional deviation between the detection valve position and the target position is within the allowable range, and the process returns without calculating the correction amount.

On the other hand, if the absolute value of the difference (ΔPS) is larger than the specific constant (PSLIM), it means that the position of the solenoid valve needs to be fed back.
Then, in step 85, it is determined whether the direction of the correction is the valve opening direction or the valve closing direction. The determination is made as to whether the difference (ΔPS) is smaller than 0. If the difference (ΔPS) is smaller than 0, it is determined that the valve closing direction is to be corrected, and the routine proceeds to step 86, where the difference (ΔPS) is determined. Is larger than 0, it is determined that the valve opening direction is to be corrected, and the routine proceeds to step 87. Step 86
In step 87, a correction amount corresponding to each valve direction is calculated, and the process returns.

After calculating the valve position feedback correction amount in step 65 of FIG. 8, the routine proceeds to step 66, where the learning value is updated based on the correction amount. In step 67, the self-diagnosis of the solenoid valve 10 is performed based on the correction amount or the learning value, and the process proceeds to step 68. In step 68, the actual solenoid valve drive duty is calculated based on the valve basic duty, the differential pressure correction amount, the valve position feedback correction amount, and the learning value, and the process proceeds to step 69. In step 69, the solenoid valve 10 is driven. Output processing.

As described above, one embodiment of the present invention has been described in detail. However, the present invention is not limited to the above embodiment, and may be designed without departing from the spirit of the invention described in the appended claims. Can be variously changed.

[0045]

As can be understood from the above description, the engine control device of the present invention can control the position of the valve body even if the solenoid valve disposed in the EGR device of the engine has a relatively large hysteresis. By detecting and controlling by comparing the detected position with the target position, it is possible to control an electromagnetic valve having both responsiveness and stability.

In addition, for the fixing failure due to contamination of the control valve or the like, the deviation between the target position and the detected position of the valve body is calculated,
Diagnosis is possible by detecting that the state in which the deviation is equal to or more than a predetermined value has continued for a predetermined time or more. Further, a change in characteristics of the control valve due to contamination of the control valve can be corrected by learning a correction amount based on the deviation for each driving direction and regulating an updating direction of the learned value according to the driving direction.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a control device of an engine with an EGR device according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a solenoid valve provided in the EGR device of the engine of FIG.

FIG. 3 is a connection diagram of the solenoid valve of FIG. 2 and a control unit of an engine control device.

FIG. 4 is a hysteresis characteristic diagram of the solenoid valve of FIG. 2;

FIG. 5 is a correction diagram of a hysteresis characteristic of the solenoid valve of FIG. 4;

FIG. 6 is a basic control block diagram of the engine control device of FIG. 1;

FIG. 7 is a specific control block diagram of the engine control device of FIG. 1;

FIG. 8 is a flowchart of the operation of a solenoid valve of the engine control device of FIG. 1;

FIG. 9 is a flowchart of calculating a basic drive duty of an electromagnetic valve in the engine control device of FIG. 1;

FIG. 10 is a flowchart for calculating a valve position feedback correction amount of a solenoid valve in the engine control device of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine body, 10 ... Control valve (electromagnetic valve), 16 ... Valve body position sensor (Valve body position detecting means), 20 ... Control unit, 47 ... Target position calculating means, 50 ... F / B correction amount calculating means, 51: learning value update means, 52: basic drive amount calculation means, 53: learning value storage means, 54: self-diagnosis means, 57: drive means

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location G01M 15/00 G01M 15/00 Z

Claims (10)

[Claims] 1. An engine control device comprising: a control valve; means for calculating a target position of a valve element of the control valve; and means for calculating a driving direction of the valve element. And a driving amount of the valve element is calculated from the driving amount, and the driving of the valve element is controlled based on the driving amount. 2. The engine control device according to claim 1, wherein the drive direction calculating means calculates a drive direction based on a change direction of the target position. 3. A control valve, means for detecting a position of a valve element of the control valve, means for calculating a target position of the valve element based on an operation state of the engine, and calculating a basic drive amount of the valve element from the target position. Means for calculating, means for calculating a correction amount based on a deviation between a target position and a detected position of the valve element, means for calculating a drive direction, and means for calculating a drive amount from the basic drive amount and the correction amount And a means for driving the control valve based on the drive amount, wherein the basic drive amount calculated based on the target position is controlled such that the control amount varies depending on the drive direction. An engine control device, characterized in that: 4. The engine control device further comprises means for diagnosing a failure of the control valve, wherein the failure diagnosing means has a deviation between a target position and a detected position of the valve body that is equal to or greater than a predetermined value, and
4. The engine control device according to claim 3, wherein when the predetermined value state continues for a predetermined time or more, the control valve is diagnosed as having failed. 5. The engine according to claim 3, wherein the engine control device includes a learning unit, and the learning unit calculates a learning amount for each driving direction of the valve body based on the correction amount. Control device. 6. The engine control device includes means for diagnosing a failure of the control valve, and the failure diagnosing means diagnoses a failure of the control valve by comparing the learning amount with a predetermined value set in advance. The engine control device according to claim 5, wherein: 7. The engine control device according to claim 5, wherein the learning unit controls the update direction of the learning value of the correction amount in accordance with a driving direction. 8. The engine control device according to claim 1, further comprising: means for correcting a basic drive amount calculated based on the target position by a pressure or a differential pressure parameter on each side of the valve body. The engine control device according to claim 1 or 3, 9. The engine control device according to claim 1, wherein the control valve is an electromagnetic valve. 10. The engine control device according to claim 1, wherein the control valve is provided in an EGR device.