JP2002250247A - Method and device for controlling internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for controlling an internal combustion engine for setting a drive signal of an adjusting element. SOLUTION: At least one maximum deviation is weighted with the quantity of secular change for forming a correction value. The quantity of secular change is set based on the frequency of fuel injection per unit time and/or the fuel pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention sets a drive signal for an adjusting element, for example, an adjusting element for determining an amount of fuel to be injected, based on a drive characteristic amount, and obtains a correction value of the drive signal based on an aging amount. The present invention relates to a method for controlling an internal combustion engine.
Further, the present invention provides an internal combustion engine having a means for setting a drive signal for an adjustment element, for example, an adjustment element for determining an amount of fuel to be injected, based on a drive characteristic amount and obtaining a correction value of the drive signal based on the aging amount. It relates to a control device.

[0002]

2. Description of the Related Art A control method for an internal combustion engine and a control device for the internal combustion engine are disclosed in DE-A-35 1021.
No. 6 discloses it. Here, a drive signal for the adjustment element of the injection pump that determines the fuel amount is set and corrected based on the drive time. For this purpose, the driving time of the internal combustion engine is supplied to the aging characteristic map, and the correction value is read based on the driving time. This correction value is used for correcting the drive signal according to a correction process dependent on the drive characteristic amount.

In this method, only the effect depending on the driving time can be considered.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control method and a control device for an internal combustion engine for setting a drive signal for an adjusting element.

[0005]

This object is achieved by weighting at least one maximum deviation by means of aging to form a correction value. The object is also achieved by setting the aging based on the number of injections per time unit and / or the fuel pressure.

[0006]

According to the measures of the present invention, the aging deterioration effect can be compensated consistently. By taking into account the number of injections during injection and / or the fuel pressure into the drive time, the occurrence of various aging effects in a given drive state is taken into account. Therefore, the present invention focuses on the fact that the duration and / or the number of injections have a great influence on aging. Furthermore, attention is paid to the fact that the fuel pressure during injection has a great effect. In a common rail system, this fuel pressure is the rail pressure. As described above, according to the method of the present invention, the driving mode can be considered.

By weighing at least one maximum deviation by means of aging to form a correction value, a very accurate and flexible correction of the aging effect becomes possible.

[0008] Advantageous embodiments and refinements of the invention are set out in the dependent claims.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments.

Hereinafter, the present invention will be described with reference to an embodiment of a common rail injector of a diesel internal combustion engine. However, the method of the invention is not limited to the application here, but can also be used for other adjusting elements. In particular, it is advantageous to use the invention in an adjusting element for fuel metering. In this case, in particular, this is a regulating element which determines the injected fuel quantity by means of a solenoid valve and / or a piezo actuator. Such an adjusting element is used, for example, in an internal combustion engine to adjust the amount of fuel injected. Thus the corresponding solenoid valve is a distributor pump, a pump nozzle unit,
Determine the start and end of injection in a common rail system or other fuel metering system.

In particular, in an injector used in a common rail system, when aging occurs, the amount of fuel metered from the injector with a certain drive signal and / or a certain drive time decreases as the life of the injector elapses. Sometimes. In the adjusting element in which the aging is described in advance, compensation is performed by the following countermeasures.

The adjustment element is designated by the reference numeral 100. The control element is supplied via a connection point 105 with a signal AD which determines the drive time of the control element and thus the quantity of fuel injected. The control unit 1 is connected to a first input side of the junction 105.
Ten signals AD0 are applied. The control unit 110 obtains the drive signal AD0 based on various drive characteristics, for example, the rotational speed of the internal combustion engine and / or a driver request. The driver demand is advantageously detected by the accelerator pedal.

The correction signal K of the selection circuit 120 is applied to a second input side of the connection point 105. The signal of the control unit 110, the signal K2 of the connection point 130, and the signal K2B of the connection point 140 are supplied to the selection circuit 120.

At the first input of node 130, node 1
32 output signals K1 are applied. Second of the connection point 130
The output signal of the tolerance setting circuit 133 is applied to the output side of the circuit. The junction 130 couples the signal K1 and the output signal of the tolerance setting circuit 133, preferably by addition.
At the second input of node 132, the maximum possible deviation M
An output signal of the setting circuit 134 for setting a signal related to AX is applied. The output signal K0 of the weight setting circuit 135 is applied to a first input side of the connection point 132. The weight setting circuit 135 is shown as a weighting characteristic curve 135. The connection point 132 is a weight setting circuit 135
Is preferably combined with the output signal of the setting circuit 134 by multiplication. The weight setting circuit 135 is supplied with the aging amount D relating to the drive time of the drive time detection circuit 136.

At the first input of node 140, node 1
Forty-two output signals K1b are applied. The output signal of the tolerance setting circuit 143 is applied to a second input side of the connection point 140. The junction 140 couples the two signals K1b and the output signal of the tolerance setting circuit 143, preferably by addition. An output signal of a setting circuit 144 for setting a signal relating to a maximum deviation MAX that can occur is applied to a second input side of the connection point 142. The output signal K0b of the weighting characteristic curve 145 is applied to a first input side of the connection point 142. The connection point 142 is the signal K0 of the weight setting circuit 145.
b and the output signal of the setting circuit 144 are advantageously combined by multiplication. The weighting characteristic curve 145 is supplied with the aging amount D relating to the drive time of the drive time detection circuit 136. Alternatively, a weighting characteristic curve 135 may be used instead of the weighting characteristic curve 145.

This device operates as follows. The structure shown in FIG. 1 is used to calculate the correction value K,
The signal AD0 for determining the injector drive time can be corrected using this correction value. Advantageously, the correction is at the junction 105
Is performed additively. Alternatively, or in addition to this, a multiplication correction may be performed.
In addition, the signal calculated based on the injector drive time can be corrected accordingly.

The correction value K is obtained as follows. The driving time detection circuit 136 sends out a signal D indicating the driving time and / or the aging amount. This signal reaches a weighting characteristic curve 135 representing the characteristics of the injector being driven. For example, when the amount of fuel to be injected is reduced as the service life elapses, a value that increases with time is stored in the weighting characteristic curve. Advantageously, this value rises between 0 and 1.

The weighting characteristic curve takes into account the time characteristic of the injector. This is approximately equal for all injectors. In a simple embodiment, the weighting characteristic is realized as an exponential function.

The quantity K0 representing the time characteristic is multiplied at the junction 132 by the maximum deviation MAX. The maximum deviation MAX indicates the maximum deviation from the closing price. This value M
AX represents a value indicating how much the injection amount has changed based on the aging over the service life. This value is preferably determined for the individual injector or for a given group of injectors.

At the connection point 130, another correction value is added to the correction value K1 thus obtained. This further correction value preferably represents the deviation between the individual injectors and the average value of all injectors. This value takes into account in particular the tolerance of the injector. Junction 13
The correction value K2 is supplied to the output side of 0.

In an advantageous embodiment, the consideration of the injector tolerance can be omitted or can be taken into account when determining the value MAX.

Advantageously, in the embodiment shown, two error components representing the time characteristic and tolerance deviation of the injector are considered separately for each injector.

In a simple embodiment, this correction value K2 is used directly as the correction value K. In a particularly advantageous embodiment, different correction values are used for different operating points. The second correction value K2b is supplied to the output of the connection point 140. This correction value is determined accordingly by blocks 142-145.

The selection circuit 120 selects the correction value K2 or K2b depending on the driving state of the internal combustion engine, and transfers it as the correction value K. In order to determine the operating state, the selection circuit 120 preferably uses the speed of the internal combustion engine, the quantity of fuel injected and / or a parameter representing these quantities. For this purpose, the selection circuit 120 uses the drive characteristic amount transmitted from the control unit 110. In this case, the driving state may be different between the two driving states as shown in FIG. 1, or may be different between the driving states of a plurality of regions.

Alternatively, the correction values may be determined at at least three operating points, and the correction characteristic map may be calculated based on the correction values. This correction characteristic map is used for correction.

FIG. 1 shows the correction according to the injector. Advantageously, corrections are made for the individual injectors. That is, the maximum deviation 134 and the tolerance 133 are set for each injector. In a particularly advantageous embodiment, the weighting characteristic curve 1
35 are individually set for each injector. Further, the aging amount D is also individually obtained for each injector. Thus, for example, when replacing the failed injector, the aging amount can be reset to zero again. By performing individual corrections for each cylinder, the injectors can be individually replaced in the event of a failure.

In the simplest case, the drive time can be determined by a drive time counter or odometer. This measure can be used in stationary engines, for example on long haul trucks, especially when the load profile is known. In vehicles with an unknown load profile, the odometer or the driving time counter does not generate a reliable signal indicating the aging of the injector.

The present invention focuses on the fact that the aging of the injector depends on the frequency of operation, ie the number of injections and the dominant fuel pressure in each case. That is, the aging of the injector is determined by the driving mode of the driver.

According to the invention, in order to compensate for the aging effect, it is determined for each checkpoint how strong the fuel quantity has changed over the service life during the measurement. The maximum deviation thus obtained is stored in the control device as a value MAX, and is weighted by a coefficient K0 depending on the aging amount D. The tolerance determined at the time of manufacture of the injector is added, so that a correction value K2 which is individually determined depending on the aging and the injector tolerance is supplied to a predetermined operating point of the injector.

The calculation of this data is performed for each operating point and each injector at the start of traveling. The use of the individual correction values is preferably such that a correction characteristic map is developed from at least three operating points based on the correction values, from which the individual values for the various operating points are read out.

In order to detect the amount of aging, the number of injections and the dominant fuel pressure during injection are detected. This fuel pressure is rail pressure in a common rail system. For this purpose, the number of injections is determined in a fixed pattern and is weighted by the rail pressure. Such detection advantageously takes place in the same time pattern as the rail pressure is detected. The amount of aging determined in this way is a measure of aging and is integrated during the driving cycle. At the end of the driving cycle, the old aging and the new aging are stored in the control device as a total, so that at the next start a correction value is calculated based on the stored values.

Alternatively, the amount of aging can be continuously detected during driving and used for calculating a correction value.

When replacing the injector within the scope of maintenance or repair, the aging amount can be selectively reset or set to a predetermined value using a so-called service tester.

A corresponding structure for determining the aging D is shown in FIG. The elements described above with reference to FIG. 1 have corresponding reference numbers. The memory unit 200 stores the aging amount D at that time. This amount of aging represents the time during which each injector was driven. That is, the aging represents the period of time that the injector has been driven since it was manufactured and / or undergoing fundamental repair. The aging amount D is supplied to the weighting characteristic curve 135 in FIG. 1 for correcting the driving time.

On the other hand, the aging amount D is calculated by adding
To reach. On the second input side of the addition point 210, the integrator 22
A signal DN which is an output signal of 0 is applied. Integrator 22
The signal of the characteristic map 230 is supplied to 0. The characteristic map 230 processes the injector drive signal AD prepared by the controller 110 and the pressure signal p of the pressure sensor. The pressure sensor 240 sends out a signal p relating to the fuel pressure. In a so-called common rail system, existing rail pressure sensors are used for this purpose, and the rail pressure sensor prepares a signal relating to the fuel pressure in the rail. The signal AD is used to detect the number of injections in a predetermined time interval.

Both the quantity representing the number of injections per time interval and the quantity representing the rail pressure are supplied to a characteristic map 230 from which the aging is determined on the basis of these two signals. The aging amount is integrated by the integrating section 220 over a predetermined time range, and thereby the signal DN is prepared.

The output signal DA of the node 210 reaches the memory unit 200 via the switching means 250.
An output signal of an external drive time setting circuit 260 is applied to a second input side of the switching means 250.

The switching means 250 is configured to store the output signal of the connection point 210 in the memory unit 200 after the integration of the aging amount by the integration section 220.
When a predetermined signal is applied to the external drive time setting circuit 260, it is supplied directly from the switching means to the memory unit.

[Brief description of the drawings]

FIG. 1 is a block diagram of the means of the present invention.

FIG. 2 is a block diagram for obtaining an aging amount.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 adjustment element 105, 130, 132, 140, 142 connection point 110 control unit 120 selection circuit 133, 143 tolerance setting circuit 134, 144 maximum deviation setting circuit 135, 145 weight setting circuit 136 driving time detection circuit

Continued on the front page F term (reference) 3G084 AA01 BA13 BA14 DA22 EB08 EC06 FA00 FA10 FA33 3G301 HA02 JA15 LB11 LC01 LC05 MA11 NA06 NA08 NC02 NE17 PB00Z PB08Z PE01Z PF03Z PG00Z

Claims (8)

[Claims] A control of an internal combustion engine, wherein a drive signal for an adjustment element, for example, an adjustment element for determining an amount of fuel to be injected is set based on a drive characteristic amount, and a correction value of the drive signal is obtained based on an aging amount. A method for controlling an internal combustion engine, wherein at least one maximum deviation is weighted by an aging amount to form a correction value. 2. A control system for an internal combustion engine, comprising: setting a drive signal for an adjustment element, for example, an adjustment element for determining an amount of fuel to be injected, based on a drive characteristic amount, and obtaining a correction value of the drive signal based on an aging amount. A method for controlling an internal combustion engine, wherein the aging amount is set based on the number of injections per unit of time and / or fuel pressure. 3. The method according to claim 1, wherein different maximum deviations are set for different operating points. 4. The method according to claim 1, wherein different weighting factors are set for each of various operating points based on the aging amount. 5. The method according to claim 1, further comprising making further corrections.
The method according to any one of claims 1 to 4. 6. The aging amount is set based on the fuel pressure and / or the number of injections per unit of time.
The method according to any one of claims 1 to 5. 7. An internal combustion engine comprising: a drive signal for an adjustment element, for example, an adjustment element that determines an amount of fuel to be injected, is set based on a drive characteristic amount, and a correction value of the drive signal is obtained based on an aging amount. A control device for an internal combustion engine, comprising means for weighting at least one maximum deviation by an aging amount to form a correction value. 8. An internal combustion engine having a means for setting a drive signal for an adjustment element, for example, an adjustment element for determining an amount of fuel to be injected, based on a drive characteristic amount and obtaining a correction value of the drive signal based on an aging amount. A control device for an internal combustion engine, comprising: means for setting the aging amount based on the number of injections per time unit and / or fuel pressure.