DE10235105B4 - Method for operating an internal combustion engine, in particular of a motor vehicle - Google Patents

Abstract

Method for operating an internal combustion engine (10), in particular of a motor vehicle, in which fuel is injected via an injection valve (26) into a combustion chamber (20) of a cylinder (12) and in which a cylinder equalization is carried out, with which the effects of different injection valves ( 26) in different cylinders (12), characterized in that the cylinder equalization a first parameter set (ZGSTnor) for normal operation of the internal combustion engine (10) and a second parameter set (ZGSTsch) for non-normal operation of the internal combustion engine (10) Is made available.

Description

State of the art

The invention is based on a method for operating an internal combustion engine, in particular of a motor vehicle, in which fuel is injected via an injection valve into a combustion chamber of a cylinder, and in which a cylinder equalization is performed with which the effects of different injection valves in different cylinders are compensated. The invention also relates to a control and regulating device for an internal combustion engine, in particular of a motor vehicle, wherein the internal combustion engine is provided with an injection valve, is injected with the fuel in a combustion chamber of a cylinder, and wherein the control and regulating device is adapted to a cylinder equalization performed to compensate for the effects of different injectors in different cylinders. Furthermore, the invention relates to an internal combustion engine, in particular for a motor vehicle, with an injection valve, is injected with the fuel in a combustion chamber of a cylinder, and with a control and regulating device which is adapted to that a cylinder equalization is performed, with the effects of different Injectors are balanced in different cylinders.

There are internal combustion engines are known in which the fuel with the aid of so-called. Piezo injectors is injected directly into the combustion chamber of the individual cylinders. In such internal combustion engines, there is a problem that due to temperature differences, different aging phenomena, and the like, the fuel masses injected from the various injectors lead to different accelerations in the respective cylinders. However, so that a uniform torque curve of the internal combustion engine is achieved, it is known to provide a so-called cylinder equalization. In such a cylinder equalization, the control of the individual injection valves and thus the fuel mass supplied via the individual injection valves to the respective cylinders is changed such that overall a uniform torque curve of the internal combustion engine is created.

The cylinder equalization described is designed such that during normal operation of the internal combustion engine, the aforementioned uniform torque curve is ensured. This may result in at least temporarily not having such a uniform torque curve in a non-normal operation.

From the DE 100 12 025 A1 a method for operating an internal combustion engine is known, in which for the purpose of a cylinder equalization injection correction factors for the correction of cylinder-individual torque errors in several operating points are determined and stored.

From the DE 101 53 520 A1 , which is to be considered as prior art in the sense of § 3 paragraph 2 PatG, a method for reading data from a fuel metering system for an internal combustion engine is known, wherein the data are taken into account by a control unit in the control of the internal combustion engine, and wherein the control unit has a cylinder equalization function.

Purpose and advantages of the invention

The object of the invention is to provide a method for operating an internal combustion engine, with which even in a non-normal operation of the internal combustion engine, a uniform torque curve thereof is ensured.

This object is achieved in a method of the type mentioned according to the invention by the features of claim 1. The object is achieved in a computer program according to the invention by the features of claim 8 and in a control and regulating device or in an internal combustion engine according to the invention by the features of claims 10 and 11.

Advantageous developments are the subject of the dependent claims.

The invention provides the cylinder equalization not only a first parameter set for normal operation of the internal combustion engine, but also a second parameter set for a non-normal operation. There is thus the possibility that the internal combustion engine is operated in a non-normal operation with the second parameter set. As a result, with the aid of the second parameter set, even in a non-normal operation of the internal combustion engine, a uniform torque curve of the same can be achieved or maintained.

The invention thus opens up the possibility of selecting the parameter set for the cylinder equalization as a function of the operating state of the internal combustion engine. This opens up the further possibility that the internal combustion engine can be operated in any operating state, ie in its normal operation, as well as in a non-normal operation with an optimum cylinder equalization, so that always a uniform Torque curve of the internal combustion engine is ensured.

In an advantageous embodiment of the invention, the second parameter set is designed such that it has faster time constants than the first parameter set. This opens up the possibility that the time constants of the first parameter set can be set optimally to the normal operation of the internal combustion engine. With the help of the faster time constant of the second parameter set, it is then preferably possible to operate the internal combustion engine after its production and after a repair-related replacement of injection valves. This has the advantage that, for example, after the production of the internal combustion engine due to the faster time constant of the second parameter set, a cylinder equalization and thus a uniform torque curve of the internal combustion engine is achieved already after a very short period of time. This would not be the case when using the slower time constant of the first parameter set. Thus, even after the manufacture of the internal combustion engine and after replacement of injection valves, the invention ensures a uniform torque curve.

Further applications and advantages of the invention will become apparent from the following description of embodiments of the invention, which are illustrated in the figures of the drawing.

Embodiment of the invention

1 shows a schematic block diagram of an embodiment of an internal combustion engine according to the invention,

2 shows a schematic longitudinal section through an embodiment of an injection valve of the internal combustion engine of 1 and

3 shows a flowchart of an embodiment of a method according to the invention for controlling and / or regulating the internal combustion engine of 1 ,

In the 1 is an internal combustion engine 10 shown, which is provided for driving a motor vehicle. The internal combustion engine 10 has several cylinders, of which in the 1 only the cylinder 12 is shown. In the cylinder 12 is a piston 14 picked up a crankshaft 16 drives. The speed of the crankshaft 16 is from a speed sensor 18 detected.

A combustion chamber 20 of the cylinder 12 can air through a suction pipe 22 and an intake valve are supplied. Via an exhaust valve and an exhaust pipe 24 can exhaust gas from the combustion chamber 20 escape.

The combustion chamber 20 can fuel via an injector 26 be supplied. The injection valve 26 is directly to the cylinder 12 assigned, allowing the fuel directly into the combustion chamber 20 is injected. The injection valve 26 is with a fuel delivery system 28 connected, from the injection valve 26 the fuel is supplied under high pressure.

The cylinder 12 is a spark plug 30 associated with the one in the combustion chamber 20 existing fuel / air mixture can be ignited. The spark plug 30 is with an ignition system 32 from which the energy required for the ignition is generated. The ignition system 32 is with a control unit 34 from which the time of ignition is determined and the ignition via the ignition system 32 is triggered.

To influence the combustion chamber 20 fuel mass to be supplied is the injection valve 26 with a power amplifier 35 connected, in turn, with the control and regulating device 34 is coupled. This is the control and regulating device 34 able to over the power amp 35 the injection valve 26 and thus to control the fuel mass to be injected.

The of the speed sensor 18 measured speed of the crankshaft 16 to the control and regulating device 34 forwarded. Furthermore, an accelerator pedal sensor 38 provided that the angular position of an accelerator pedal 40 detected. This angular position is from the accelerator pedal sensor 38 to the control and regulating device 34 passed. In response to the above and other input signals controls and / or controls the control and regulating device 34 including the spark timing of the spark plug 30 , the injection timing as well as into the combustion chamber 20 fuel mass to be injected via the injection valve 26 and the same.

In the 2 is the injector 26 shown in more detail. At the injection valve 26 it is a so-called piezo injector.

The injection valve 26 has a valve body 42 on, at the brennraumseitigem end an outlet opening 44 for the fuel is present. This can be done via an outwardly opening valve needle 46 with an annulus 48 connected in turn with the fuel supply system 28 connected is. The metering of fuel takes place via the open valve needle 46 resulting annular gap.

That from the outlet opening 44 opposite end of the valve needle 46 is fixed with a piezo actuator 50 coupled. With this piezo actuator 50 it is a layered column made up of a plurality of individual piezoelectric elements.

That of the valve needle 46 opposite end of the piezo actuator 50 is with a housing part 52 of the injection valve 26 firmly jammed. In this area is the piezo actuator 50 via a control line 54 with the power amplifier 35 connected.

To realize an injection of fuel through the annular gap in the combustion chamber 20 the internal combustion engine 10 becomes the injection valve 26 over the power amplifier 35 from the control and regulating device 34 subjected to an electrical signal. This causes the piezo actuator 50 enlarged in its longitudinal direction. This will cause the valve needle 46 from her in the area of the outlet opening 44 existing valve seat on the valve body 42 lifted off, leaving the outlet opening 44 with the annulus 48 and thus with the fuel delivery system 28 connected is. Because of the fuel supply system 28 generated high fuel pressure is now an injection of fuel over that of the outlet opening 44 and the valve body 42 formed annular gap.

If this injection should be terminated, then the control of the piezo actuator 50 ended with the electrical signal. The piezo actuator 50 resumes its initial length and the valve needle 46 comes back to her valve seat of the valve body 42 to the plant.

For a uniform as possible course of the rotational movements of the crankshaft 16 it is necessary that all cylinders 12 the internal combustion engine 10 an equal share to the drive of the crankshaft 16 deliver. Under the same operating conditions so the different cylinders 12 the internal combustion engine 10 generate equal torques. This is achieved by means of a so-called cylinder equalization.

When the cylinder is equalized, the acceleration of the crankshaft 16 after the ignition of the fuel / air mixture in each of the cylinders 12 with the help of the speed sensor 19 determined. These accelerations are for all cylinders 12 the internal combustion engine 10 determined. From the deviations of the accelerations for different cylinders 12 can be closed to different fuel masses in each cylinder 12 have been injected. These different fuel masses result from different changes in length of the respective associated piezo actuators 50 ,

On the basis of the determined cylinder-specific accelerations is by the control and regulating device 34 the fuel mass to be injected for the individual cylinders 12 adapted so that for all cylinders 12 the internal combustion engine 10 ultimately result in uniform accelerations. This means that of the control and regulating device 34 the electrical signals with which the individual piezo actuators 50 the different cylinder 12 the internal combustion engine 10 be controlled, are adapted so that overall a uniform as possible torque curve of the internal combustion engine 10 is obtained.

This adaptation of the electrical signals with which the piezo actuators 50 the different cylinder 12 be acted upon by the control and regulating device 34 performed by means of a control and / or regulation and with the aid of an adaptation. The time constants of the controls and / or controls of the described cylinder equalization are normal operation of the internal combustion engine 10 aligned. The same applies to the adaptation of this cylinder equalization, which is also aligned to the normal operation and thus provided with larger time constants.

There is thus a parameter set ZGSTnor, which is responsible for the normal operation of the internal combustion engine 10 is provided. With this parameter set ZGSTnor is a cylinder equalization of different cylinders 12 the internal combustion engine 10 reached in normal operation.

After the production of the internal combustion engine 10 or after a repair-related replacement of injection valves 26 It is possible that large deviations of the accelerations of different cylinders 12 available. This results from the fact that immediately after the production of the internal combustion engine or immediately after the repair-related replacement of injectors 26 the cylinder equalization was not yet able, the deviations of the different cylinders 12 compensate. For this purpose, the cylinder equalization requires a certain amount of time, which ultimately of the normal operation of the internal combustion engine 10 dependent parameter set ZGSTnor and the time constant specified there.

So even after the production of the internal combustion engine 10 or after a repair-related replacement of injection valves 26 as quickly as possible an approximation of the accelerations of the different cylinders 12 the internal combustion engine 10 and thus as quickly as possible a uniform torque curve of the internal combustion engine 10 is reached, a second parameter set ZGSTsch is provided for the cylinder equalization.

This second parameter set ZGSTsch differs from the first parameter set ZGSTnor in that it is not suitable for normal operation of the internal combustion engine 10 is provided, but only immediately after the production of the internal combustion engine 10 or after a repair-related replacement of injection valves 26 is used. The second parameter set ZGSTsch is chosen such that the time constants present there are significantly shorter than the time constants present in the first parameter set ZGSTnor.

With the help of the shorter time constant of the second parameter set ZGSTsch is achieved that after the production of the internal combustion engine 10 or after a repair-related replacement of injection valves 26 the following cylinder equalization much faster to an approximation of the different cylinders 12 the internal combustion engine 10 leads than would be the case with the use of the first parameter set ZGSTnor.

The second parameter set ZGSTsch can therefore be referred to as a fast parameter set, which after the manufacture of the internal combustion engine 2 or after replacing injectors 26 is used, while it is the first parameter set ZGSTnor a normal parameter set, which - as explained - is used in normal operation of the internal combustion engine. In the 3 a method is shown, with which the selection of the first or second parameter set ZGSTnor, ZGSTsch for the cylinder equalization is performed. The procedure is performed by the control and regulating device 34 executed. For this purpose, the control and regulating device on a computer that is loaded with a computer program. The computer program has a sequence of program instructions, which ultimately in the 3 realized and explained below method realize. The computer program can, for. B. be stored on a flash memory.

From the control unit 34 the mentioned cylinder equalization is carried out again and again. This can be done at constant intervals or triggered by predeterminable events. To carry out the cylinder equalization, a parameter set is required.

In the 3 will be in a block 60 queried whether the internal combustion engine is in normal operation or not. The internal combustion engine 10 then is not in normal operation, if it was just made or if just a repair to the internal combustion engine 10 was carried out. It is possible that other specifiable conditions can lead to the internal combustion engine 10 not in normal operation.

The aforementioned conditions are determined by the control and regulating device based on operating variables of the internal combustion engine 10 checked. These operating variables may, for example, be binary signals that indicate that a repair of the internal combustion engine is currently taking place 10 has been carried out. The control unit decides on the basis of these operating variables 34 whether the internal combustion engine 10 in normal operation or not.

Is the internal combustion engine 10 in their normal operation, the cylinder equalization of the intended for normal operation first parameter set ZGSTnor is assigned. This is in the 3 based on the block 62 shown.

Is the internal combustion engine 10 However, not in their normal operation, the cylinder equalization is assigned the second parameter set ZGSTsch. This is in the 3 through the block 64 shown.

The block 64 is according to the 3 a block 66 downstream. This query checks whether the fast, second parameter set ZGSTsch may actually be used. With the help of the block 66 Thus, the use of the second parameter set ZGSTsch can be terminated, even if the normal operation of the internal combustion engine is not recognized via the block.

When querying the block 66 it may, for example, be a time condition. Thus, it is possible that a predefinable maximum time duration is realized via the query, during which the second parameter set ZGSTsch is only permitted. So in the block 60 found that the internal combustion engine 10 is not in its normal operation, and then the second parameter set ZGSTsch is assigned to the cylinder equalization, then via the block 66 ensures that this second parameter set ZGSTsch is only used for the aforementioned maximum period of time. If this maximum period of time has expired, then the block 66 switched back to the first parameter set ZGSTnor.

Similarly, it may be in the query of the block 66 to act on a condition that affects the fuel mass. Thus, it can be achieved with the help of the query that the second parameter set ZGSTsch is used only so long until a maximum fuel mass in the internal combustion engine 10 has been injected. After that is from the block 66 in turn switched back to the first parameter set ZGSnor.

In a similar way can over the block 66 any further or other conditions for the switching back from the second, fast parameter set ZGStsch to the first, normal parameter set ZGSTnor be provided.

Furthermore, it is possible that with the switching back to the first parameter set ZGSTnor additionally from the block 66 those conditions are affected by the block 60 in view of the presence or absence of the normal state of the internal combustion engine 10 be queried. Thus, for example, it is possible that the already mentioned binary signals with which a currently performed repair of the internal combustion engine 10 is displayed by the block 66 when switching back to the first parameter set ZGSTnor also be reset.

By the method of the 3 is achieved that the fast, second parameter set ZGSTsch is used exactly when the internal combustion engine 10 not in normal operation. Furthermore, by the method of 3 ensures that the second parameter set ZGSTsch is switched back to the first, normal parameter set ZGSTnor under certain conditions, for example after the expiration of a maximum period of time. This makes it possible that after the production of the internal combustion engine 10 or after a repair-related replacement of injection valves 26 possibly existing deviations between the different cylinders 12 the internal combustion engine 10 quickly resolved and thus a uniform torque curve of the engine 10 can be reached quickly.

The method described can also be used with appropriate modifications when using a solenoid valve or other injector instead of the piezo actuator.

Claims (13)

Method for operating an internal combustion engine ( 10 ) in particular of a motor vehicle, in which fuel via an injection valve ( 26 ) in a combustion chamber ( 20 ) of a cylinder ( 12 ) and in which a cylinder equalization is performed, with which the effects of different injection valves ( 26 ) in different cylinders ( 12 ), characterized in that the cylinder equalization a first parameter set (ZGSTnor) for a normal operation of the internal combustion engine ( 10 ) and a second parameter set (ZGSTsch) for non-normal operation of the internal combustion engine ( 10 ) is made available. A method according to claim 1, characterized in that the second parameter set (ZGSTsch) is designed such that it has faster time constants than the first parameter set (ZGSTnor). Method according to one of the preceding claims, characterized in that the second parameter set (ZGSTsch) is used after the internal combustion engine ( 10 ) or after at least one of the injectors ( 26 ) of the internal combustion engine ( 10 ) has just been exchanged. Method according to one of the preceding claims, characterized in that on the basis of operating variables of the internal combustion engine ( 10 ) is checked, whether the internal combustion engine ( 10 ) is in a normal operating state, and that depending on the first or the second parameter set (ZGSTnor, ZGSTsch) is selected. Method according to one of the preceding claims, characterized in that when using the second parameter set (ZGSTsch) it is checked whether a predefinable condition is fulfilled, which is required for the use of the second parameter set (ZGSTsch). A method according to claim 5, characterized in that it is checked whether a maximum period of use of the second parameter set (ZGSTsch) has expired. A method according to claim 5 or 6, characterized in that it is checked whether a maximum fuel mass during use of the second parameter set (ZGSTsch) is reached. A computer program comprising a sequence of program instructions adapted to carry out the method of any one of the preceding claims when executed by a computer. Computer program according to claim 8, characterized by its storage on an electronic data carrier, in particular a flash memory. Control and regulating device ( 34 ) for an internal combustion engine ( 10 ) in particular of a motor vehicle, wherein the internal combustion engine ( 10 ) with an injection valve ( 26 ), with the fuel into a combustion chamber ( 20 ) of a cylinder ( 12 ) is injected, and wherein the control and regulating device ( 34 ) is set up to have a Cylinder equalization is performed with which the effects of different injectors ( 26 ) in different cylinders ( 12 ), characterized in that the control and regulating device ( 34 ) is arranged such that the cylinder equalization a first parameter set (ZGSTnor) for a normal operation of the internal combustion engine ( 10 ) and a second parameter set (ZGSTsch) for non-normal operation of the internal combustion engine ( 10 ) is made available. Internal combustion engine ( 10 ), in particular for a motor vehicle, with an injection valve ( 26 ), with the fuel in a combustion chamber ( 20 ) of a cylinder ( 12 ) and with a control and regulating device ( 34 ), which is adapted to perform a cylinder equalization with which the effects of different injectors ( 26 ) in different cylinders ( 12 ), characterized in that the control and regulating device ( 34 ) is arranged such that the cylinder equalization a first parameter set (ZGSTnor) for a normal operation of the internal combustion engine ( 10 ) and a second parameter set (ZGSTsch) for non-normal operation of the internal combustion engine ( 10 ) is made available. Control and regulating device ( 34 ) according to claim 10 or internal combustion engine ( 10 ) according to claim 11, characterized in that the injection valve ( 26 ) a piezo actuator ( 50 ) or is designed as a solenoid valve. Control and regulating device ( 34 ) according to claim 10 or 12 or internal combustion engine ( 10 ) according to claim 11 or 12, characterized in that the injection valve ( 26 ) for the direct injection of fuel into the combustion chamber ( 20 ) is provided.

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