DE102015200565A1 - Method and device for adapting a component of an internal combustion engine - Google Patents

Abstract

The present invention relates to a method for adapting a component (310) of an internal combustion engine, in particular a component of a fuel metering system of an internal combustion engine, in which it is provided that deviations of the component to be adapted into aging-related deviations and deviations due to series dispersion are distinguished deviations caused by series scattering are adapted (350) by an initial adaptation carried out at the end of the production of the component, and that deviations due to aging are adapted in the operation of the internal combustion engine or of the fuel metering system (355, 360).

Description

State of the art

The invention relates to a method and a device for adapting a component or a component of an internal combustion engine, in particular a component or a component of a Kraftstoffzumesssystems an internal combustion engine, according to the preamble of claim 1. Furthermore, the invention relates to a computer program, a machine-readable data carrier for Storage of the computer program and an electronic control unit, by means of which the inventive method is feasible.

Today's control units of internal combustion engines contain a large number of adaptation algorithms in order to adapt an original parameterization of an ideally ideal internal combustion engine (so-called "golden application engine") to deviations of an operated unit or component of a real internal combustion engine caused by aging effects and specimen or series variations adapt. Such an adaptation relates, for example, to the derivation of a cylinder internal pressure and a torque from a rotational speed signal of an internal combustion engine by means of a so-called MWF method described below (MWF = "mechanical work feature" = feature for mechanical work). This known method allows in principle the diagnosis and adaptation of a plurality of different components or units of an internal combustion engine.

In fuel injection systems of internal combustion engines is also known that the injected into a cylinder or combustion chamber of an internal combustion engine fuel quantity under certain conditions with a so-called PMI ("indicated mean effective pressure" = indexed mean pressure) of the respective cylinder correlates. This can also be determined on the basis of a feature based on an evaluation of the speed signal and obtained by said MFW method. Certain operating or boundary conditions are, for example, stoichiometric or even lean combustion, so that a quantity of fuel is converted as completely as possible.

So go out DE 10 2008 054 690 A1 a method and a device for calibrating the injection quantity of a partial injection in an injection system of an internal combustion engine, in which an adaptation or correction value for the partial injection is determined in a single cylinder of the internal combustion engine by stimulation of at least two injection patterns. In particular, a physical variable determined from a rotational speed signal of the internal combustion engine and characteristic of the combustion is used. The characteristic physical quantity is the torque curve or the energy or work converted during combustion. It is preferably determined by comparison of the characteristic variables thus determined in a single injection and a multiple injection, whether the injection quantity of the partial injection deviates from a predetermined value.

Further, go out DE10 2008 054 757 A1 a frequently used in control devices of internal combustion engines method of adaptation, in which an adaptation of a calculated by the control unit loss torque to an actual torque loss of the engine takes place. During idling of the internal combustion engine, ie in operation without a consumer, only a torque is expended by the internal combustion engine, which is required to compensate for the torque losses. For this purpose, for example, a loss torque modeled for a respective operating point is compared with a torque requested by an idling speed controller and adapted accordingly by means of one or more adaptation values.

Disclosure of the invention

The invention is based on the idea that, in the case of an adaptation of a component or aggregate (hereinafter referred to as "component") of an internal combustion engine or an injection system of an internal combustion engine, deviations in deviations caused by said aging effects and deviations caused by said series dispersion effects are the basis differ.

By an initial training of occurring at the end of the production of a component series dispersion of a characteristic of the operation of the component size or a corresponding technical feature (so-called. Initialadaption), the invention allows much tighter tolerances in the adaptation of aging effects, as in known Influence of series dispersion only the aging effects in the operation of the component during adaptation have to be considered.

In particular, the invention is based on the finding that at the end of production of a component concerned here there are only series variations, but still no aging effects which only occur or can occur over the lifetime of the component.

The invention enables a considerable simplification of an adaptation affected here as well as a considerable improvement of the adaptation quality or the diagnostic grade in a functional diagnosis of a component affected here.

The method according to the invention for adapting a component of an internal combustion engine or a fuel metering system provides, in particular, for deviations of the component to be adapted into deviations due to aging and deviations due to series dispersion, such that deviations caused by series scattering are carried out by one at the end of the production of the component Initial adaptation are adapted, and that due to aging deviations in the operation of the internal combustion engine or the fuel metering system are adapted. This distinction advantageously considerably reduces the tolerance range of the component available for the adaptation.

In the method according to the invention, it can be provided that the said initial adaptation of the component takes place by initial learning of a deviation of a variable characteristic for the operation of the component as well as by storage of the learned deviation of the characteristic variable. Such training can be carried out at the end of the production process of the component with relatively little effort. The deviation, which is preferably stored on the component itself due to the series scattering, wherein the storage can be carried out on a microchip or whereby a bar code, QR code or the like can also be used, is thus readily available for the later operation of the component.

In the method according to the invention, it can further be provided that a limited tolerance range for the possible adaptation of deviations due to aging is determined on the basis of the stored deviation adapted by the initial adaptation and that the limited tolerance range in a subsequent assessment of the necessity of an adaptive correction intervention characteristic size in the operation of the internal combustion engine or the fuel metering system is based. Such a limited tolerance range offers the already mentioned advantages of a simpler and thus faster and more cost-effective adaptation.

In the method according to the invention, it can further be provided that the stored value of the deviation can be reset via an operating intervention. This makes it possible to reset the deviation data stored for an already adapted component back to the original state during a component change and to adapt the deviation caused by the series deviation of the new component. Such an intervention may e.g. be a tester intervention.

In the method according to the invention, it can further be provided that a current value of the characteristic variable is determined, that the determined current value of the characteristic variable is compared with the value of the characteristic variable adapted by initial adaptation, that when the determined value of the characteristic variable is exceeded, one empirically predetermined threshold value, the determined current value of the characteristic variable is compared with the limited tolerance range and only when exceeding the limited tolerance range, a said adaptive correction intervention is performed. By means of this preliminary check, the required resources or computing capacities for the implementation of the method according to the invention can be further reduced since the actual adaptation must be carried out only in certain cases.

Finally, in the method according to the invention, it can be provided that a named adaptive correction intervention consists of inhibiting adaptations and / or setting error flags. Such a corrective intervention can be implemented with relatively little technical effort, since existing resources (control devices etc.) can be used for the adaptation.

In particular, the invention can be used in an electronic control unit for controlling an internal combustion engine affected here or in a corresponding control unit of a fuel metering system which is affected here. In this case, the fuel metering in particular also includes the range of partial injections described at the outset, ie. from with respect to one or more main injections applied pre- and / or post-injections.

It is understood, however, that the application is not limited to the application examples described herein and also in other components or areas (components, units, etc.) of an internal combustion engine, in which an adaptation of a characteristic size or a corresponding technical feature described herein a component is required, can be used with the advantages described herein. As examples of these other ranges, on the one hand, the field of exhaust aftertreatment is mentioned, e.g. the injection or metering of urea (HWL) in an SCR system, and the other part of a high-pressure fuel storage system (common rail or CR), in which fuel and air is supplied via controllable valves.

The computer program according to the invention is set up to carry out each step of the method, in particular if it runs on a computing device or a control device. It allows the implementation of the method according to the invention on an electronic control unit, without having to make structural changes to this. For this purpose, the machine-readable data carrier is provided on which the computer program according to the invention is stored. By applying the computer program according to the invention to an electronic control unit, the electronic control unit according to the invention is obtained, which is set up to control an internal combustion engine or in particular a fuel metering system of an internal combustion engine by means of the method according to the invention.

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination indicated, but also in other combinations or in isolation, without departing from the scope of the present invention.

Brief description of the drawings

1 shows a schematic representation of a fuel metering system of an internal combustion engine according to the prior art, in which the present invention can be used.

2 shows a detailed representation of the known calculation of driving durations in the 1 shown electrically operated valve.

3 shows typical tolerance ranges of a technical feature of an affected here component of an internal combustion engine to illustrate the inventive method.

4 shows an embodiment of the method according to the invention or a corresponding routine with reference to a flowchart.

Description of exemplary embodiments

1 shows a block diagram of the essential elements of a fuel metering system of an internal combustion engine. The internal combustion engine 10 obtained from a fuel metering unit 30 a certain amount of fuel at a given time metered. Various sensors 40 capture readings 15 , which characterize the operating state of the internal combustion engine, and forward them to a control unit 20 , The control unit 20 also different output signals 25 additional sensors 45 fed. The recorded measured values 15 characterize the state of the fuel metering unit such as a driver's request. The control unit 20 calculated from these measurements 15 and the other sizes 25 drive pulses 35 with which the fuel metering unit 30 is charged.

The internal combustion engine is preferably a direct-injection and / or a self-igniting internal combustion engine. The fuel metering unit 30 can be configured differently. For example, as a fuel metering unit, a distributor pump can be used in which a solenoid valve determines the time and / or the duration of the fuel injection.

Furthermore, the fuel metering unit can be designed as a common rail system. In this known to compress a high-pressure pump fuel in a memory. From this memory then the fuel passes through injectors into the combustion chambers of the internal combustion engine. The duration and / or the beginning of the fuel injection are controlled by the injectors. In this case, the injectors preferably include a solenoid valve or a piezoelectric actuator.

The control unit 20 calculates in known manner the fuel quantity to be injected into the internal combustion engine. This calculation is dependent on different measured values 15 , such as the speed n, the engine temperature, the actual start of injection and possibly other variables 25 that characterize the operating condition of the vehicle. These other variables include the position of the accelerator pedal or the pressure and the temperature of the ambient air. The control unit 20 then converts the desired amount of fuel into corresponding drive pulses of the injectors.

In the mentioned internal combustion engines, one or more small quantities of fuel are often metered into the cylinder shortly before the actual main injection. As a result, the noise behavior of the engine can be significantly improved. This injection is referred to as the pilot injection and the actual injection as the main injection. Furthermore, it can be provided that a small or a plurality of fuel quantities are metered after the main injection. This is then called post-injection. Furthermore, it can be provided that the individual injections are divided into further partial injections.

The problem with such fuel metering systems is that the electrically actuated valves can meter different amounts of fuel with the same drive signal. In particular, the driving time at which fuel is being metered depends on various factors. This minimum drive duration leads to an injection, whereas drive times smaller than the minimum drive duration do not lead to an injection. This Mindestansteuerdauer depends on various factors, such as the temperature, the fuel grade, the life, the rail pressure, manufacturing tolerances of the injectors and other influences. In order to achieve an accurate fuel metering, this Mindestansteuerdauer must be known.

A device for controlling the metering of fuel in a combustion chamber of an internal combustion engine is in 2 shown. Already in 1 Elements described are designated by corresponding reference numerals. Signals from the sensors 45 as well as other sensors, which are not shown, reach a quantity specification 110 , This quantity specification 110 calculates a fuel quantity QKW that corresponds to the driver's request. This quantity signal QKW reaches a connection point 115 , at the second input of which the output signal QKM of a second synchronization 155 is applied. The output signal of the first node 115 arrives at a second node 130 which in turn is a driving duration calculation 140 applied. At the second input of the second node 130 the signal QKO is a zero-quantity correction 142 at.

In the two connection points 115 and 130 the quantity signals are preferably linked additively. The drive duration calculation 140 calculated from the output of the node 130 the drive signal for acting on a Kraftstoffzumesseinheit 30 , The actuation duration calculation calculates the actuation duration with which the electrically actuated valves are acted upon.

On a donor wheel 120 Different markers are arranged by a sensor 125 be scanned. In the illustrated embodiment, the sender wheel is a so-called segment wheel, which has a number of markings corresponding to the number of cylinders, in the exemplary embodiment illustrated this is four. This donor wheel is preferably arranged on a crankshaft of the internal combustion engine, not shown. This means that per motor revolution, a number is generated at the pulses, which corresponds to twice the number of cylinders. The sensor 125 supplies a corresponding number of pulses to a first synchronization 150 ,

The first synchronization 150 applies a first regulator 171 , a second regulator 172 , a third controller 173 and a fourth controller 174 , The number of controllers corresponds to the number of cylinders. The output signals of the four controllers then go to the said second synchronization 155 ,

Such a device, without zero-offset 142 is equipped in the DE 195 27 218 shown in more detail. This facility works as follows. Based on various signals, such as a signal that identifies the driver's request, determines the quantity specification 110 the fuel quantity request signal QKW, which is required to provide the driver's desired moment. In addition to the driver request signal also other signals can be processed. In particular, the speed signal and various temperature and pressure values are processed in addition to the driver request signal. Furthermore, there is the possibility that signals from other control units are transmitted to the quantity specification requesting a torque request and / or a quantity request. Such another control device may, for. B. be a transmission control, which influences the torque from the engine during the switching process.

Due to tolerances, in particular the fuel metering unit 30 Deviations occur between the desired injection quantity and the actually injected fuel quantity. The individual cylinders of the internal combustion engine usually measure different amounts of fuel with the same drive signal. These variations between the individual cylinders are usually compensated with a quantity compensation control (MAR). Such a quantity compensation control is schematically in the upper part of 2 shown. For quantity balance control each cylinder of the internal combustion engine is assigned a controller. So the first cylinder is the first regulator 171 , the second cylinder the second regulator 172 , the third cylinder is the third regulator 173 and the fourth cylinder, the fourth controller 174 assigned. It can also be provided that only one controller is provided, which is assigned alternately to the individual cylinders. By means of the sensor 125 and the donor wheel 120 determines the first synchronization 150 a setpoint and an actual value for each individual controller. It is provided that to compensate for tolerances of the encoder wheel and to compensate for torsional vibrations a special filtering of the signal of the sensor 125 he follows. The output signals of the controller 171 to 174 become a second synchronization 155 supplied, which provides a correction amount QKM, with the quantity request QKW is corrected.

This quantity compensation control is designed such that the regulators regulate the quantity metered to the individual cylinders to a common mean value. If a cylinder measures an increased fuel quantity due to tolerances, a negative fuel quantity QKM is added to the driver's desired quantity QKW for this cylinder. If a cylinder measures too little fuel quantity, then a positive fuel quantity QKM is added to the driver desired quantity QKW. With such quantity errors, rotational nonuniformity occurs. This has the effect that the speed signal oscillations are superimposed whose frequency of the camshaft frequency and / or multiples of the camshaft frequency correspond.

These components in the speed signal with camshaft frequency characterize the rotational nonuniformity and are compensated by the amount compensation control to zero.

It should be noted that quantity average errors can not be corrected with this quantity compensation scheme. In particular, errors which are based on the fact that no fuel is metered in below the specified minimum driving time can not be corrected with such a quantity compensation control.

In the following, it is assumed that at the end of a production of a component or aggregate affected here (hereinafter "component") only series variations exist, but still no aging effects, which can only occur over the lifetime of the component.

3 shows a typical deviation of a characteristic quantity or a plotted on the vertical axis of the diagram technical feature of a component of an internal combustion engine from the optimal position, which is given by the horizontal zero line and horizontal axis. This may, for example, be a prescribed fuel injection quantity or a loss torque. In conventional components such features vary due to the series dispersion when installed in an internal combustion engine or a corresponding motor vehicle within the dotted lines 300 . 305 delimited area. The two values 310 (x1) and 315 (x2) correspond to deviations from two separately manufactured components of a construction type, which move within the series deviation ± Δs. The vertical double arrows 320 and 325 represent the inventively adapted, respectively permissible tolerances over the lifetime ± .DELTA.l, so that in total by the two dashed lines 330 . 335 indicated range, which differs from the upper value 340 (ao) to the lower value 345 (au) extends.

According to the method of the invention (see also 4 ) is for a particular component, in the present example the component 310 (x1), first the deviation 350 (a1) of the affected feature at the end of production or at the end of a tape production and stored. After that, for the considered component 310 (x1) around the value 350 (a1) around a newly limited tolerance range 355 (a1o) to 360 (a1u). This tolerance range is much narrower than the original range 330 . 340 (a0) to 335 . 345 (au), since the necessary allowance for the series spread ± Δs is omitted. In a subsequent assessment of the need for a corrective intervention or a system reaction according to the invention, only the described limited tolerance range of 355 (a1o) to 360 (a1u).

It should be noted that the stored value of the deviation 350 (a1) of the component of the component concerned here 310 (x1) can be reset, for example via a tester intervention, so that in the case of a change of the component in a workshop a new training can be done.

After the start 400 the in 4 a routine m derived by means of the above-described MWF method is determined 405 as well as in 2 according to step 150 , In step 410 It is checked whether it is an initial adaptation, ie an initial adaptation at the end of production or a tape or a reset via a tester. If it is such an initial adaptation, then the value of the feature m is stored as value a1 415 and the routine ends 420 ,

Otherwise, m is compared with the feature stored in a1 425 , In the case of a deviation exceeding an empirically set threshold, the limited tolerance range of 355 (a1o) to 360 (a1u) read out or retrieved 430 and the value of the feature m with this tolerance range 355 . 360 compared 435 , Otherwise, by step 425 back to the beginning 400 jumping back to the routine. Returns the mentioned comparison 435 with the limited tolerance range that this is exceeded upwards or downwards, is called a corrective intervention in the injection system or a corresponding system response 440 completed and the routine subsequently terminated 445 , It should be noted that a said system reaction may also consist of inhibiting adaptations or setting error flags or the like. Returns the comparison 435 that the limited tolerance range is not exceeded, the routine becomes after performing the step 435 ended directly 445 ,

The method described can be implemented in the form of a control program for an electronic control unit for controlling an internal combustion engine or in the form of one or more corresponding electronic control units (ECUs).

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008054690 A1 [0004]
• DE 102008054757 A1 [0005]
• DE 19527218 [0035]

Claims (9)

Method for adapting a component ( 310 ) of an internal combustion engine, in particular a component of a fuel metering system of an internal combustion engine, characterized in that to be adapted deviations of the component are differentiated due to aging deviations and deviations caused by series deviations that adapted by series scattering deviations adapted by performing at the end of the preparation of the component initial adaptation become ( 350 ), and that deviations caused by aging are adapted in the operation of the internal combustion engine or of the fuel metering system ( 355 . 360 ). A method according to claim 1, characterized in that the initial adaptation of the component by initially learning a deviation of a for the operation of the component ( 310 ) characteristic size (x1) and by storing the learned deviation of the characteristic size (x1). A method according to claim 2, characterized in that on the basis of the stored, adapted by the initial adaptation deviation ( 350 ) a limited tolerance range ( 355 . 360 ) is determined for the possible adaptation of deviations due to aging and that the limited tolerance range ( 355 . 360 ) is used in a subsequent assessment of the need for an adaptive correction intervention of the characteristic variable (x1) in the operation of the internal combustion engine or the fuel metering system. Method according to claim 2 or 3, characterized in that the stored value of the deviation ( 350 ) can be reset via an operator intervention. Method according to claim 3 or 4, characterized in that a current value of the characteristic quantity (x1) is determined that the determined current value of the characteristic quantity (x1) matches that determined by initial adaptation (x1). 350 ) Value of the characteristic quantity (x1) is compared, that when the determined value of the characteristic quantity (x1) of an empirically predetermined threshold value is exceeded, the determined current value of the characteristic quantity (x1) with the limited tolerance range (x1) 355 . 360 ) is compared ( 435 ) and when the limited tolerance range ( 355 . 360 ) a said adaptive correction intervention is performed. Method according to one or more of Claims 3 to 5, characterized in that a said adaptive correction intervention consists of inhibiting adaptations and / or setting error flags. A computer program configured to perform each step of a method according to any one of claims 1 to 6. Machine-readable data carrier on which a computer program according to claim 7 is stored. Electronic control unit, which is set up to control an internal combustion engine or in particular a fuel metering system of an internal combustion engine by means of a method according to one of claims 1 to 6.

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