JP2004316643A - Internal combustion engine operating method, and device for controlling operation of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine operating method, a control device and a computer program in which high accuracy is realized when metering the fuel by a high-pressure injection valve in an internal combustion engine. <P>SOLUTION: In the internal combustion engine operating method, at least one injection valve of an internal combustion engine is drive-controlled according to a characteristic curve of the flow rate and the electrical quantity to indicate individual characteristics of the injection valve in use when the internal combustion engine is operated. The control device controls the internal combustion engine based on the individual D<SB>i</SB>(Q<SB>i</SB>) characteristic curve with the gradient (k<SB>i</SB>) corrected by the method. The computer program is operated on a computing unit allotted to this controller, such as a microprocessor, and has a program code suitable to execute the method. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for operating an internal combustion engine, and more particularly to a method for driving and controlling an injection valve of an internal combustion engine. The invention further relates to a control device for the operation of the internal combustion engine and to a computer program for such a control device.

  In the prior art, for example, from DE 100 11 690 A1 or DE 100 12025 A1, a method for compensating injection valve quantity errors of internal combustion engines is basically known. The methods known from these documents relate, in particular, to the adaptation of the quantity tolerances in high-pressure fuel injectors in the stratified mode of the internal combustion engine (λ> 1). These methods are universal. That is, the present invention is applicable to fuel injection valves having different structures and functions.

  In view of future internal combustion engines with optimized spray guides, high pressure fuel injectors have been developed. Here, the flow rate or the amount of fuel to be injected into the combustion chamber of the internal combustion engine is controlled via the injection time ti of the injection valve i and / or the needle stroke NH. The desired needle stroke NH is set and adjusted in such a high-pressure injection valve by adding the corresponding required quantity of electricity to the desired injection time ti. The quantity of electricity required for the desired drive control is calculated in each case on the basis of a reference characteristic curve stored in a control device for controlling the injection valve. In such a reference characteristic curve, the flow rate D is represented by the electric quantity (Ladung) Q to be added on the horizontal axis.

Such a D (Q) reference characteristic curve NH _Ref is shown in FIG. This stored reference characteristic curve represents the characteristic of the selected reference valve or the average characteristic of a number of high-pressure injection valves manufactured of the same type. This reference characteristic curve therefore differs from the characteristics of the individual injection valves of the same type manufactured and used. Such different characteristic curves are represented by the reference symbols NH1 or NH2 in FIG. The methods described in the documents cited at the outset, which adapt the quantity tolerances in the high-pressure injector, do not take into account the above-mentioned differences between the average and individual properties of the high-pressure injector. This difference can also cause inaccuracies in fuel metering.
German Patent No. 10011690 DE 100 12025 A1

  An object of the present invention is to provide an operation method, a control device, and a computer program of an internal combustion engine that realize high accuracy when fuel is metered by a high-pressure injection valve in the internal combustion engine.

An object of the invention is to provide an internal combustion engine characterized in that, during operation, at least one injection valve of the internal combustion engine is driven and controlled in accordance with a flow-electricity characteristic curve representing the individual characteristics of the used injection valve. And a control device for controlling an internal combustion engine on the basis of individual D _i (Q _i ) characteristic curves having a gradient (k _i ) corrected by this method, and in particular this control device The invention is solved by a computer program running on a computing device, for example a microprocessor, assigned to the computer program and having program code suitable for performing the method described above.

  By taking into account such individual characteristic curves, the accuracy at the time of fuel metering is remarkably improved compared to the conventional technology in which a characteristic curve representing only the average characteristic of the same type of injection valve was used. Is done. Such improved metering accuracy also allows the use of a spray-guided combustion method for the operation of internal combustion engines, which is planned in the future. This combustion method is distinguished by lower exhaust gas emissions and lower consumption compared to conventional methods. The advantages of the control device and the computer program according to the invention correspond to the advantages described above in connection with the method of the invention.

  Advantageous configurations of the method according to the invention are described in the dependent claims.

  BRIEF DESCRIPTION OF THE DRAWINGS The invention is explained in more detail below in the form of various embodiments with reference to the drawings.

In particular, FIG. 1 shows a method for calculating the slope of the flow-electrical characteristic curve for the individual high-pressure injection valves of an internal combustion engine. Here gradient k _i represents the flow rate, the ratio of the amount of electricity to be added to the injection valve in order to obtain the desired needle stroke NH or flow rate. To determine such a gradient, the internal combustion engine is first operated in a so-called homogeneous mode, ie, for example, λ = 1 (step a)).

  Then, in a subsequent step b), a so-called adaptation area (Adaptionsbereich) is defined. A reference operating point is appropriately selected within this adaptation region. Unless such a matching area is defined, the method of the invention does not proceed, but instead returns to step a) repeatedly.

After successfully reaching the adaptation region, the reference operating point is set and adjusted in such an adaptation region. This reference operating point is characterized in particular by the fact that the rotational speed of the internal combustion engine and the respective relative air masses supplied to the internal combustion engine are quasistationers. Further, for example, λ = 1 and the injection time ti _Ref belonging to this reference operating point and the belonging electric quantity Q _Ref to be added to the injection valve are drive-controlled (step c)).

As soon as such a reference operating point has been set, it is checked whether the single cylinder-lambda measurement is active in the internal combustion engine (step d). As long as it is not active, the method according to the invention goes into a waiting loop. This is achieved by returning to step c). However, if single cylinder-lambda measurement is active, the quantity of electricity to be applied to the injector is adjusted by a preset value ΔQ with respect to the quantity of electricity Q _Ref to be applied for the setting adjustment of the reference operating point. Is done. By adjusting the quantity of electricity by ΔQ in this manner, first, the lambda changes by the value Δλ. In this case, the reference operating point does not substantially change. This is because in homogeneous mode the moment formation is only slightly affected by the combustion lambda.

Under the prerequisites described here, that is, under the premise that both the relative air mass rl and the injection duration ti each remain static, such an identified lambda change is defined by the injection valve Corresponds to a specific change ΔD in the amount of fuel flowing through the fuel cell. From the two quantities Δλ and ΔQ or ΔD and ΔQ, the individual gradient of the injector i used is calculated according to the following formula:
k _i = Δλ: ΔQ = ΔD: ΔQ (1)
With such individual gradients k _i , a correction factor f _koor is calculated. This correction factor is the deviation of the individual slopes k _{i from} the slope of the predetermined reference characteristic curve which represents the average characteristic of a number of manufactured injection valves of the same type. The calculation of the correction factor f _koor is calculated according to the following formula:
_{f koor = k i: k Ref} (2)
The identification of the change of the quantity λ resulting from the adjustment of the quantity of electricity and the calculation of the correction factor are performed in step f) of FIG. If the calculation of the correction factor is not successful, the method according to the invention is adapted to return to the start of step d).

However, on the other hand, if the calculation of the correction factor has been carried out successfully, it is used in step g) to calculate the individual D _i / Q _i characteristic curves for the used injector i. As already mentioned above, the correction factor f _koor calculated according to the invention is only used to match the slope of the D (Q) characteristic curve to the actual characteristic of the injector. Possible offset errors are not taken into account in the method of the invention.

During subsequent operation of the internal combustion engine, the D _i (Q _i ) characteristic curve calculated and matched correspondingly with the present invention, as represented by the return from step g) to step a) in FIG. Advantageously, if possible offset errors are negligible, or equally appropriate, as compared with the errors compensated by the invention in the slope of the characteristic curve of the injector used with respect to the reference characteristic curve. It is used only when it is corrected by an appropriate method.

  FIG. 3 shows a control device 100 that drives and controls an injection valve of an internal combustion engine according to the above-described method.

  The method according to the invention is also implemented at least partly as a computer program. This computer program is preferably executed on a computing device 110 (FIG. 3) assigned to the control device 100, for example a microprocessor. This can itself be stored on a computer-readable data carrier, together with another computer program for opening and / or closing the internal combustion engine. The data carrier is, for example, a floppy disk, a compact disk or a so-called flash memory. The computer program stored on the data carrier can be sold to the customer as a product. In the case of a software implementation, furthermore, this computer program, possibly together with another computer program for opening and / or closing the internal combustion engine, may be used without the aid of an electrical data carrier, especially in an electronic communication network, in particular, Via the Internet, products can be transmitted to customers and sold in that way.

5 is a flowchart showing the method of the present invention.

3 is various flow rate versus electric quantity characteristic curves for a high pressure injection valve.

It is a figure showing the control apparatus of operation of an internal combustion engine.

Explanation of reference numerals

100 control device 110 computing device

Claims (8)

During operation, controlling at least one injection valve of the internal combustion engine in response to a flow-electrical quantity characteristic curve representing individual characteristics of the injection valve used;
An operation method for an internal combustion engine, comprising: The method according to claim 1, wherein the flow-electrical characteristic curve for the individual injection valve is calculated by modifying a predetermined reference characteristic curve with a modification factor f _koor . The correction factor f _koor is _calculated by the following equation:
f _koor = k _i : k _Ref ;
Calculated according to
Where k _i represents the slope of the characteristic curve for the individual injection valves, k _Ref represents the gradient of the reference characteristic curve, The method of claim 2 wherein. Perform the following steps to calculate the gradient k _i of the flow rate (D) versus the electric quantity for the individual injection valves (i) of the internal combustion engine (Q) characteristic curve, namely:
Operating the internal combustion engine in homogeneous mode, preferably with λ = 1 (step a)),
- reference electrical quantity for each reference injection duration _{(t Ref)} by the drive control of the _{(Q Ref)} by the injection valve (i), and set adjusting the reference operating point of an internal combustion engine (step c)),
Changing the electric quantity for driving and controlling the injection valve (i) by a predetermined value (ΔQ) with respect to the reference electric quantity (Q _Ref ) (step d));
Identifying the change (Δλ) in lambda value resulting from the change in electric quantity (ΔQ) in the internal combustion engine (step f));
The individual gradients k _i for the injectors are:
k _i = Δλ: ΔQ = ΔD: ΔQ (1)
Where Δλ = ΔD is only valid under the assumption that both the relative air mass (rl) and the injection duration (ti) are constant (step f)),
The method of claim 3.   5. The method according to claim 4, wherein the setting of the reference operating point in step c) is performed only within a predetermined adaptive operating range of the internal combustion engine.   6. The method according to claim 5, wherein the change of the quantity of electricity (.DELTA.Q) is performed in order to identify the resulting change of the lambda value (.DELTA..lambda.) Only if the single cylinder-lambda measurement is active according to step d). Method. In particular, in a control device (100) for the operation of an internal combustion engine in a vehicle,
The control device (100), controls the internal combustion engine based on the individual D _{i (Q i)} characteristic curve having a gradient that is corrected according to the method of any one of claims 1 to 6 (k _i) Are configured to
A control device, characterized in that: In a computer program for a control device of an internal combustion engine,
In particular, the computing device (110) assigned to the control device has a program code which is operated on a microprocessor and is suitable for performing the method according to one of the claims 1 to 6. ,
A computer program characterized by the above-mentioned.

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