DE102007061225A1 - Internal combustion engine operating method, involves processing output signals of combustion chamber pressure sensor to heating process, and deriving parameter characterizing injected fuel amount from heating process - Google Patents

Abstract

The method involves processing output signals (pZyl) of a combustion chamber pressure sensor (7) to a heating process. A parameter characterizing an injected fuel amount is derived from the heating process. Heat amount is transferred with a predetermined crankshaft angle, and is used for characterizing the injected fuel amount. Injection amounts of cylinders of the internal combustion engine are controlled, and combustion noise of the cylinder of an internal combustion engine (1) is controlled. Independent claims are also included for the following: (1) a computer program with a program code for performing a method for operating an internal combustion engine (2) a control device for an internal combustion engine.

Description

State of the art

A method and an apparatus for controlling an internal combustion engine are known from DE 10 2006 001 367 A1 known.

With The method described there, starting from a combustion chamber pressure signal, that is provided by a combustion chamber pressure sensor, a noise characteristic formed and this noise characteristic used to control the internal combustion engine.

to Compliance with emission limits throughout the lifetime an internal combustion engine must be ensured that the tolerances of the emission relevant sensors and actuators of the Internal combustion engine over the entire life of the internal combustion engine stay within preset limits.

From particular importance for compliance with emission limit values are naturally the tolerances of sensors in the Intake tract and the injectors of the injection system. With the help of known from the prior art method it is possible to ensure by regulating the combustion noise that the combustion noise over the entire Life of the internal combustion engine remains within predetermined limits.

Disclosure of the invention

Of the Invention is based on the object, a faster Ausregel the occurring during operation of the internal combustion engine Allow sensor or actuator errors and also extend the range within which the occurring sensor or actuator errors or their drift be compensated can.

These Object is according to the invention in a method for operating an internal combustion engine having at least one combustion chamber pressure sensor, with at least one injector and with a control unit, solved in that the output signals of the combustion chamber pressure sensor to a heating process, in particular an integral heating process, be recycled, and that from the heating HV at least one the injected fuel quantity q characterizing size Q is derived.

This makes it possible to deduce the injected fuel quantity q from the output signals of the combustion chamber pressure sensor via the heating curve HV. In case of deviations of the actually injected fuel quantity q _is q from the predetermined amount of fuel _sol can be made appropriate corrections in the control of injectors and thus the injected fuel quantity q _is be controlled to the target value q _sol. Since the regulation of the injected amount of fuel can ultimately be done from one cycle to the next cycle of the internal combustion engine, this scheme is very fast and it can be a very high control quality can be achieved. At the same time, it is also possible to regulate the injected fuel quantity over a very wide range to the desired value and to perform this control in parallel to the noise control known from the prior art.

It has proven to be advantageous if the at a given Crankshaft angle α converted energy Q for characterization the injected fuel q serves.

This Method has the advantage that, for example, by an empirical Choice of different crankshaft angles α at a first Pre-injection, at a second pilot injection or another pre-injection and implemented in the main injection Energy quantities can be recorded and evaluated individually. As a result, it is with the invention Procedures possible in the pilot injections and the main injection to determine individually injected fuel quantities and in each case to supply a control, so that both the pilot injections as well as the main injections can be regulated individually. As a result, both the pilot injections as well as the main injections over the entire service life the internal combustion engine are kept within very narrow limits can, what a condition for the permanent Compliance with emission limit values.

The inventive method is understood not limited to two pilot injections and one main injection, but in principle can also be used with injections more than three partial injections and / or at least one post-injection be used.

To the information obtained by the inventive process on the injection amount q _is be able to use for controlling the internal combustion engine is further provided that the serving for the characterization of the injected fuel quantity values of a control of the injection amount is supplied. It is particularly advantageous if each injector of the internal combustion engine is controlled by the method according to the invention, since the injectors of an internal combustion engine are subject to different wear, so that only by an individual control of the injectors a uniform operating behavior of all injectors or all cylinders over the entire life of the internal combustion engine can be realized.

A further, particularly advantageous embodiment of the invention Procedure provides that in addition to the scheme of Injection quantities the combustion noise of the internal combustion engine is regulated, so that also the combustion noise over the entire life of the internal combustion engine corresponds to the desired value. The fact is exploited that deviations of the fresh air mass and / or the exhaust gas recirculation rate a change cause the combustion noise, so that through the Regulation of the combustion noise also compensates for errors in the fresh air mass become.

An advantage of this combination of several regulations is that the inventive control of the injected fuel amounts compensates for closure or error of the injectors, while the control of the combustion noise according to the DE 10 2006 001 367 A1 , to which reference is expressly made, the drift of an air mass meter, or compensated for errors in the air mass or in the exhaust gas recirculation. Because with this combination of regulations the regulation of the injection quantity according to the invention takes place much faster than the regulation of the air masses or the exhaust gas recirculation rate, the comparatively sluggish regulation of the air mass or the exhaust gas recirculation rate by means of the noise control is improved by the inventive regulation of the injected fuel quantities.

Further Advantages and advantageous embodiments of the invention are the subsequent drawing, the description and the claims removable. All in the drawing, the description and the claims disclosed features can be used both individually and in Any combination with each other essential to the invention.

It demonstrate:

1 a block diagram of an operating according to the inventive internal combustion engine; and

2 a more detailed representation of the signal processing according to the invention.

Based on 1 the method according to the invention will be explained with reference to a block diagram.

With 1 is an internal combustion engine called an injection system 3 and an intake tract 5 having. For clarity, the injection system 3 only shown as a block, wherein for each cylinder of the internal combustion engine 1 an injector is present.

At the internal combustion engine 1 are a combustion chamber pressure sensor 7 and a rotation angle sensor 9 arranged. Alternatively, it is also conceivable for each cylinder of the internal combustion engine 1 to provide a pressure sensor which is acted upon directly by the pressure prevailing in the combustion chamber.

The output signals of the combustion chamber pressure sensor 7 and the rotation angle sensor 9 become a function block feature analysis with the reference numeral 11 fed. This function block 11 is as well as the elements of the block diagram described below in an engine control unit of the internal combustion engine 1 implemented.

In the feature analysis 11 are the signals of the sensors detected at high resolution 7 and 9 in accordance with the invention spreads. The preparation of these signals is below in connection with the 2 explained in more detail. However, it is important that in the feature distribution 11 Various treatments take place for the regulation of both the intake tract 5 or an air mass meter HFMI and for correcting the injection quantities of the injectors of the injection system 3 be used.

A first output signal of the feature preparation 11 is hereinafter referred to as M _{VG, is} designated and characterizes a combustion noise of the internal combustion engine 1 , The output MVG becomes a first node 13 fed.

In the first link 13 is the output signal M _{VG, is} from a target value of the combustion noise M _{VG, is} subtracted and a noise control 15 fed. Output of the noise control 15 is a signal m _{L, correction} , which is in a second link 17 is linked to the output signal m _{L, HFMI} an air mass sensor not shown HFMI. The thus corrected output signal m _{L, HFMI, Korr} becomes an air regulator 19 fed. The output of the air regulator 19 is in a third node 21 with the from a map 23 read out values for the control of the intake tract 5 merged.

About this scheme, essentially comprising the combustion noise controller 15 and the air regulator 19 , the drift of the air mass meter HFMI can be corrected over the entire service life of the internal combustion engine. Thus, the To contribution of the intake tract 5 over the entire life of the internal combustion engine 1 be kept within narrow limits. This control circuit is due to the inertia of the intake system 5 located air and exhaust gas masses comparatively sluggish.

additionally to the thus achieved correction of drift of the air mass meter But HFMI could also be the boost pressure control and the control a valve with which the exhaust gas recirculation done, be corrected.

A second output of feature editing 11 is the amount of heat converted at a first pilot injection QPil1 _Ist . This output QPil1 _Ist is in another link 25 subtracted from the setpoint QPil1 _Sol the amount of heat converted and a first heat quantity regulator 27 fed. In the controller 27 the amount of heat QPil1 converted in the first pilot injection Pil1 is regulated.

The output of the first heat quantity regulator 27 will be in another link point 29 to correct the from a map 31 read value for the fuel quantity to be injected q _Pil1 , added for the first pilot injection Pil1. The corrected value q _Pil1Korr becomes the associated injector of the injection system 3 the internal combustion engine 1 driven.

A similar regulation also takes place for the second pilot injection Pil2. This in feature editing 11 provided output signal QPil2 _Ist is via an addition point 33 a second heat quantity regulator 35 fed. The output signal of the second heat quantity regulator 35 is in an addition point 37 with one from a map 39 Fuel quantity to be injected q _Pil2 added and to control the second pilot injection of the injector 3 used.

The same applies to the heating heat Q _Miist the main _injection MI. The function blocks belonging to this regulation are an addition point 41 , a third heat quantity regulator 43 , an addition point 45 and a map 47 for the amount of fuel to be injected in the main injection _MI q _MI .

By the inventive feature processing 11 So it's possible, not just on the noise control 15 the drift of the air mass meter HFMI over the entire life of the internal combustion engine 1 but also the quantities of fuel injected by the quantities Q _Pil1, Q, Q _Pil2, and Q MI are to be separately _detected both in the pilot injections PIL1, PIL2 and in the main injection MI, respectively, and in individual regulators 27 . 35 and 43 to regulate.

The regulators 27 . 35 and 43 correct those from the associated maps 31 . 39 and 47 selected fuel _quantities to be injected q _Pil1 , q _Pil2 and q _MI and thereby ensure that over the entire life of the internal combustion engine 1 always the desired amounts of fuel are injected both in the pilot injections and in the main injection.

Since the regulation of the injected fuel quantities q has no inertia, it is ensured that, firstly, the injected fuel quantities q always largely correspond to the desired desired value and, secondly, by this "pre-regulation" also the quality of the regulation of the air path or the intake tract 5 is improved.

In 2 is subsequently the Aufbreitung the output signals of the combustion chamber pressure sensor 7 in feature editing 11 explained.

On the abscissa of in 2 represented diagram, the crankshaft angle α is plotted. In this case, a crankshaft angle α = 0 corresponds to the top dead center of the relevant piston.

On the Y axis is the heating curve HV plotted in Joule. The heating process HV is an integral value during injection or a work cycle, the energy conversion was shown.

Furthermore, in 2 three lines 49 . 51 and 53 applied. This corresponds to the first line 49 the heating process HV of a correctly working internal combustion engine 1 , The second line 51 represents a heating course HV, in which more fuel is injected and as a result, the amounts of energy Q are greater than in the illustrated operating point of the internal combustion engine 1 desired. The third line 53 represents a heating course HV at which the injector injects less fuel than intended.

How out 2 As can be seen, at a crankshaft angle α = -4 °, a first energy conversion begins, which reaches a plateau at a crankshaft angle α _{R, Pil1} . This crankshaft angle α _{R, Pil1} corresponds to a converted heat quantity Q _Pil1 when the internal combustion engine is operating correctly. This heat quantity Q _Pil1 can be derived from the first line 49 at the point α _{R, Pil1} read out. The angle α _{R, Pil1} must be through test bench tests with the internal combustion engine 1 be determined once.

At the end of this plateau Q _Pil1 , the first line rises from an angle α greater than 1 ° 49 again, because in the meantime a second pilot injection Pil2 has been made and takes place according to an energy conversion in the combustion chamber of the internal combustion engine. At a crankshaft angle α _{R, Pil2} of approximately 5 °, a variable Q _{Pil2 of} the heating profile HV characteristic of the injected fuel quantity q _{Pil2 is} reached. The same applies to the crankshaft angle α _{R, Mi} at about 9 °. At this crankshaft angle α _{R, Mi} , a heating heat Q _Mi from the first line 49 which is representative of the injected fuel quantity q _{Mi of} the main injection MI.

The inventive method thus makes a property of the heat-release Q-to-use, at the suitably selected angles α _{R, Pil1,} α _{R, pIL2} and α _{R, Mi} from the lines 49 . 51 and 53 _Heating heat Q _Pil1 , Q _Pil2 and Q _Mi can be read, which are representative of the fuel injected at the pilot injections Pil1, Pil2 and the main injection Mi amounts of fuel.

When the internal combustion engine 1 works perfectly and the injectors are not subject to any wear, then correspond to the feature processing 11 determined outputs Q the on the first line 49 lying points.

However, since the heating process changes due to the wear and possible malfunction of the injectors and, for example, that through the second line 51 or by the third line 53 from the deviation of the read-out values Q _Pil1 , Q _Pil2 and Q _Mi on wear or drift of the injector can be concluded and this quantity for the regulation of the pilot injections and the main injection in the controllers 27 . 35 and 43 according to 1 be evaluated.

For example, if a cylinder of the internal combustion engine 1 a heating course Q corresponding to the second line 51 has, _read at an angle α _{R, Pil2} instead of a heat of 50 joules, an approximately twice as large value of about 90 joules. That is, the heat quantity Q _{Pil2, Ist has} a value of about 90 joules, while the set value Q _{Pil2, Sol} , as off 2 is removable, is about 50 joules. The resulting controller deviation becomes the node 33 formed and the regulator 35 fed.

The same applies to the first pilot injection Pil1 and the main injection Mi. Of course, deviations of the heat from the ideal line, through the first line 49 is not only up, but also down, as exemplified by the third line 53 is shown.

It is important, however, that by an inventive treatment of the output signal of the combustion chamber pressure sensor 7 for each injector of the internal combustion engine, the actual injected fuel quantities can be made separately for the pilot injections and the main injection.

Since, of course, each injector of an internal combustion engine undergoes individual wear and drift during the operating period of the internal combustion engine, the method according to the invention with the controllers 27 . 35 and 43 to perform for each injector of the internal combustion engine. For clarity, this is only for one injector 3 shown.

Activation of the controller 15 . 27 . 35 and 43 takes place via the load and / or speed dynamics of the internal combustion engine 1 ,

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102006001367 A1 [0001, 0013]

Claims (10)

Method for operating an internal combustion engine ( 1 ) with at least one combustion chamber pressure sensor ( 7 ), with an air mass sensor (HFMI), with at least one injector ( 3 ) and with a control unit, characterized in that the output signals (pZyl) of the combustion chamber pressure sensor ( 7 ) are processed to a heating curve (HV), and that from the heating curve (HV) at least one of the injected fuel quantity (q) characterizing size (Q) is derived. Method according to claim 1, characterized in that that at a given crankshaft angle (α) converted amount of heat (Q) to characterize the injected Fuel quantity (q) is used. Method according to Claim 1 or 2, characterized in that the quantity of heat (Q _Pil1 ) converted at a first crankshaft angle (α _{R, Pil1} ) is used to characterize the quantity of fuel (q _Pil1 ) injected during a first pilot injection (Pil1). Method according to one of the preceding claims, characterized in that at a second crankshaft angle (α _{R, Pil2} ) converted amount of heat (Q _Pil2 ) for characterizing the injected in a second pilot injection (Pil2) fuel quantity (q _Pil2 ) is used. Method according to one of the preceding claims, characterized in that the amount of heat (Q _MI ) converted at a third crankshaft angle (α _{R, MI} ) serves to characterize the amount of fuel (q _MI ) injected during a main injection ( _MI ). The method (according to any one of the preceding claims, characterized in that the characterization of the injected fuel quantity (q, q _Pil1, q _pIL2, q _MI) serving sizes (Q, Q _Pil1, Q _pIL2, Q _MI) of a control 27 . 35 . 43 ) of the Einspitzmenge is supplied. A method according to claim, characterized in that the injection quantities of each cylinder of the internal combustion engine ( 1 ) are regulated individually. Method according to one of the preceding claims, characterized in that a combustion noise of at least one cylinder of the internal combustion engine ( 1 ) is regulated. Computer program with program code for execution all the steps according to one of the preceding claims, if the computer program is running from a computer becomes. Control unit for an internal combustion engine, characterized in that it is according to one of the preceding method claims 1 to 7 works.