JP2004183657A - Method and device for controlling fuel amount adjusting system of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve quality of control and to reduce time required for compensating the amount of an injecting. <P>SOLUTION: A driving time from a start value is increased or decreased in at least one driving state of an internal combustion engine to generate a certain rotation speed in the internal combustion engine. The driving time when the certain rotation speed occurs is stored as a minimum driving time in at least one driving state. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The invention relates to a fuel metering for an internal combustion engine, which first determines the minimum drive time during which fuel is exactly injected in a given drive state, in order to determine the amount of fuel injected by the drive time of at least one electrically operated injector. The present invention relates to a system control method.

  The invention also provides for determining the amount of fuel to be injected by the drive time of at least one electrically operated injector, first determining a minimum drive time during which fuel is just injected in a given drive state, The invention relates to a control device for a fuel metering system for an internal combustion engine, comprising means for increasing or decreasing the drive time from a start value in two drive states and storing the drive time at which the signal has changed as a minimum drive time.

  A control method and a device for a fuel metering system of an internal combustion engine are described, for example, in DE-A-199 45 618. In this known method, the amount of injected fuel is determined by the drive time of at least one electrically operated valve. The minimum drive time during which fuel is just injected in a given drive state is determined. That is, the drive time is increased or decreased starting from the start value, and the drive time up to the time when the signal representing the injection has changed is stored as the minimum drive time. According to this method, the drift of the injection amount can be corrected in the pilot injection region as long as the life of the injection nozzle is maintained.

  Unpublished German patent application DE 102 15 610 describes a method and a system for correcting the injection characteristics of an injector. Here, injector quantity compensation is performed at a plurality of inspection points to improve quality. This preferably takes place at four points: pilot injection, idle operation, discharge point, full load operation.

  Such injector amount compensation is essential. This is because such injectors have different quantity characteristic maps due to mechanical manufacturing errors. The quantity characteristic map represents the correlation among the injection quantity, the rail pressure, and the drive time. As a result, different fuel amounts are injected into the combustion chambers from the individual injectors even when electrically defined control is performed.

  Since the fuel consumption must be kept as low as possible while complying with strict exhaust gas standards, very small production tolerances are allowed for the injectors in terms of injection volume. After production, the injection quantity is measured and classified at a characteristic operating point or test point in order to ensure accurate injection quantity formation with low injector errors. Each class must be known to the engine control as the operating mode of the internal combustion engine, and the control process is adapted to the characteristics of the class for each injector. The classification information is stored in the injector as various codes (for example, a bar code), represented by the resistance of the injector, or pasted as clear text.

  Further, an electronic storage means may be provided in the injector to store the classification information. The controller reads these values from the injector via the interface and uses them for subsequent operations.

Such an injector amount compensation method (IMA method) is basically a means based on correlation. A quantity drift is concluded as a property map by correlation and extrapolation based on the quantity compensation properties observed at the four test points.
German Patent Application Publication No. 199 45 618 German Patent Application No. 10215610 specification (not disclosed)

  It is an object of the present invention to provide a method and a device for compensating for an injector quantity of the type mentioned at the outset, while improving the quality of the control and further reducing the time required for injector quantity compensation.

  The object is to increase or decrease the drive time from a starting value in at least one operating state of the internal combustion engine to produce a constant rotational speed in the internal combustion engine, and to reduce the drive time at which the constant rotational speed occurs to at least one drive time. This is solved by storing the minimum drive time in the drive state.

  The object is also achieved by providing means for increasing or decreasing the drive time in such a way that a constant speed of the internal combustion engine occurs in at least one operating state.

  The concept of the present invention is to reduce the number of inspection points for injector quantity compensation and shorten the inspection time. That is, in at least one driving state of the internal combustion engine, a constant rotation speed is generated by changing the injection amount at the inspection point corresponding to the state, and the driving time at which the rotation number occurs is set as the minimum driving time, and the state is set as the minimum driving time. Is stored in correspondence with the inspection point of (1). Such an approach is based on the knowledge that a constant friction ratio exists, especially in new internal combustion engines, and that a constant rotational speed is achieved corresponding to a predetermined injection quantity being metered.

  According to an advantageous embodiment of the invention, a constant rotational speed is generated by varying the drive time, and the minimum drive time obtained is determined during idling of the internal combustion engine. This embodiment is particularly advantageous when the invention is used in an internal combustion engine having an idling control circuit. According to such an idling control circuit, a constant idling speed can be set. The minimum drive time determined in this way under a constant idling speed is corrected for injector quantity compensation, preferably by extrapolating the minimum drive time determined at the discharge point of the internal combustion engine, The corrected value is stored in the injector or the engine control device.

  For example, a parameter indicating rotation non-uniformity, an output signal of a lambda sensor, an output signal of an ion flow sensor, or the like is used as the signal indicating the injection. Furthermore, the parameter of the quantity compensation control unit or the output signal itself of the quantity compensation control unit can be used as the signal.

  Other features and advantages of the present invention will be described in detail below with reference to the illustrated embodiment.

  FIG. 1 shows the high-pressure section of the common rail accumulator injection system. In the following, only the main components that are important for understanding the invention will be described.

  The system has a high-pressure pump 10, which is connected via a high-pressure line 12 to a high-pressure accumulator (rail) 14. The high-pressure accumulator 14 is connected to an injector 18 via a further high-pressure line 16. The injector 18 is incorporated in a vehicle internal combustion engine. The illustrated system is controlled by the engine control device 20. The engine control device 20 controls the injector 18 in particular.

  The injector 18 is provided with a device 22 for storing information about the individual injector 18. The information stored in this device 22 is considered by the engine control device 20 and each injector 18 is individually controlled. This information is preferably a correction value for the quantity characteristic map of the injector 18. The information storage device 22 may be, for example, a data memory, one or more electrical resistors (eg, bar codes), alphanumeric lock codes, etc., and a semiconductor located on the injector 18. It may be realized by an integrated circuit. The engine control device 20 also has a semiconductor integrated circuit for evaluating the information stored in the device 22.

  The injection amount measured from each injector 18 is set in a characteristic map stored in the engine control device 20 depending on the rail pressure. Here, this characteristic map is determined on the basis of a plurality of test points representing various operating states of the internal combustion engine, namely pilot injection, idling operation, discharge point and full load. Once at each of these inspection points, a quantity compensation is performed in a manner known per se (for example, in the manner described in unpublished German patent application DE 102 15 610). The injection amount is determined by the injection time of the injector 18, that is, the time from the start of injection to the end of injection.

  In order to be able to perform fuel metering over the entire operating range (characteristics map) of the internal combustion engine and the injector 18, the compensation values between the support positions defined by the test points are interpolated. Compensation values other than the support position defined by the inspection point are obtained by extrapolation.

The internal combustion engine has an idling control circuit 30, and an output signal thereof is supplied to the engine control device 20. Constant idling speed n ₀ by the idling control circuit 30 is set in advance.

  For example, it is not necessary to carry out the quantity compensation process at all of the inspection points known from the unpublished German patent application DE 102 15 610, which will be described below with reference to FIG.

  First, in step S100, the injector amount compensation IMA is performed by a method known per se (for example, by a method known from unpublished German Patent Application No. 10215610). This injector quantity compensation is not performed at all inspection points, but is performed only at three points, for example, pilot injection, discharge point, and full load. The idling operation, which is the fourth inspection point, is subsequently determined in step 120 based on the value determined by the injector amount compensation. This is done, for example, by extrapolating the emission point-IMA value taking into account known correlations. The value obtained here is stored as the idling point minimum driving time for the time being.

Constant idling speed _{n 0} is adjusted by the idle control circuit 30 in further step S140. This is done by changing the driving time of the injector 18 to form a difference in the idling speed n ₀ that has been set. That is, the drive time is reduced and / or increased until the desired target rotational speed is reached. This is based in particular on the knowledge that in a new internal combustion engine a constant friction ratio exists and a predetermined injection quantity is determined when a certain target speed is reached. The drive time at the time when the idling rotational speed n ₀ occurs is obtained, and this value is stored in, for example, the injector 18 or the engine control device 20 as the idling point minimum drive time.

  In this way, the idling point-IMA value is obtained without compensating the injector quantity at the idling point.

  The idling point-IMA value is obtained in advance by finding the minimum driving time at a constant idling rotation speed and correcting this by extrapolation / correlation of the emission point-IMA value. However, the invention is not limited to such a process, and alternatively or additionally other IMA inspection points may be determined as described above. This is done, for example, by forming a constant rotational speed and extrapolating / correlating it based on the IMA value. The test point for which the minimum drive time is genuinely required can be located at any point in the characteristic map by forming a constant rotational speed. In this way, for example, the second pilot injection can be compensated, and the quality of injector amount compensation can be further improved.

It is a figure showing a part of common rail system of the present invention.

4 is a flowchart of an embodiment of the method of the present invention.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 10 High-pressure pump 12, 16 High-pressure pipe 14 Rail 18 Injector 20 Engine control device 22 Device for storing information 30 Idling control circuit

Claims (7)

In order to determine the amount of fuel injected by the drive time of the at least one electrically operated injector, the minimum drive time during which fuel is just injected in a given drive state is first determined;
In a control method of a fuel metering system for an internal combustion engine,
Increasing or decreasing the drive time from the starting value in at least one operating state of the internal combustion engine to produce a constant rotational speed in the internal combustion engine;
A method for controlling a fuel metering system for an internal combustion engine, wherein a driving time at which a certain number of revolutions occurs is stored as a minimum driving time in at least one driving state.   2. The method according to claim 1, wherein the drive time is increased or decreased until a change in the signal representing the injection takes place, and the drive time is stored as a minimum drive time (injector quantity compensation).   The signal representing the injection is one or more of a parameter representing rotation non-uniformity, an output signal of the lambda sensor, an output signal of the ion flow sensor, a parameter of the quantity compensation control unit, and an output signal of the quantity compensation control unit. 3. The method of claim 2.   4. The method as claimed in claim 2, wherein the injector quantity compensation is performed for pilot injection, discharge points and full load test points.   By determining the minimum drive time at which a constant rotational speed occurs in the idling operation of the internal combustion engine, and by extrapolating the starting value used for increasing or decreasing the drive time to at least one minimum injection time determined by injector quantity compensation. The method according to claim 1, wherein the method determines.   6. The method according to claim 5, wherein the starting value is determined by extrapolating at least one minimum injection time determined at the discharge point of the internal combustion engine by means of injector quantity compensation. In order to determine the amount of fuel injected by the operating time of the at least one electrically operated injector, the minimum operating time during which fuel is exactly injected in a given operating state is first determined, and the internal combustion engine is started in at least one operating state. A control device for a fuel metering system for an internal combustion engine, comprising: means for increasing or decreasing a drive time from a value and storing a drive time at which a signal has changed as a minimum drive time.
A control device for a fuel metering system for an internal combustion engine, comprising means for increasing or decreasing a driving time so that a constant rotation speed is generated in the internal combustion engine in at least one driving state.

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