EP1081363B1 - Method to control an internal combustion engine - Google Patents

Description

State of the art

The invention relates to a method for operating a Internal combustion engine, in particular of a motor vehicle, in which Fuel in at least two operating modes in a combustion chamber is injected, depending on one Operating mode map switched between the operating modes and in which the operating mode map is dependent is adapted from operating variables of the internal combustion engine. The The invention also relates to a corresponding control device for such an internal combustion engine.

Such a method and such a control device are known for example from DE 196 40 403 A1.

With a so-called gasoline direct injection Fuel in homogeneous operation during the intake phase or in a shift operation during the compression phase in injected the combustion chamber of the internal combustion engine. The Homogeneous operation is preferred for full load operation Internal combustion engine provided for during shift operation idle and part-load operation is suitable. For example depending on a desired target operating mode in such a direct injection internal combustion engine switched between the above modes.

To switch between the operating modes is in the Control unit provided a mode map in which each operating point of the internal combustion engine the associated one Operating mode is saved. This operating mode map is used for internal combustion engines of the same type Manufacture stored identically in the control unit.

Between the internal combustion engines of the same type are due of tolerances and the like. Likewise internal combustion engines are subject to one during their lifetime Aging. The result of this is that for each operating point saved operating modes after a certain time possibly no longer optimal for the respective Are internal combustion engine. However, this means that the respective internal combustion engine no longer operated optimally becomes.

The object of the invention is to provide a method for operating to create an internal combustion engine with which over the entire Running time of all internal combustion engines of the same type optimal operation is achieved.

This task is carried out in a method of the type mentioned at the beginning Art according to the invention by the features of the characteristic Part of claim 1 solved. With a control unit of the task mentioned is the object of the invention solved accordingly.

The operating mode map is thus over the entire duration the internal combustion engine is automatically and continuously optimized. The internal combustion engine is thus always operated optimally. By adapting the operating mode map Scattering between internal combustion engines of the same type, such as also automatically compensates for aging effects. By doing Operating mode map are for everyone at any time Operating point of the internal combustion engine the optimal operating mode stored.

According to the invention, one or several operating mode and operating point dependent Comparative quantities determined. This way the whole Procedure simplified and a subsequent comparison be relieved.

Furthermore, for the same operating point Comparative values of different operating modes with each other compared. So it finds an operating point dependent Comparison instead, in which the comparison variables of the associated, different operating modes can be compared. With With the help of this comparison the effects of different operating modes in the specific operating point be determined. This is the impact around the above-mentioned farm sizes, e.g. to the Efficiency and / or smoothness and / or the Exhaust emissions from the internal combustion engine.

According to the invention, depending on the comparison optimal operating mode selected for the operating point and in the operating mode map is written. Because of the So comparison is one of the modes of operation as optimal Operating mode determined and selected. This optimal Operating mode is then in the operating mode map stored.

This means that the operating mode map is maintained throughout Running time of the internal combustion engine always optimized adaptively. Scattering between internal combustion engines of the same type or Aging effects in internal combustion engines are thus during of the operation automatically compensated.

In an advantageous development of the invention as Operating parameters of efficiency and / or smoothness and / or determines the exhaust gas emission of the internal combustion engine. This Company sizes have proven particularly useful for the Adaptation of the operating mode map and thus for the Optimization of the operation of the internal combustion engine exposed.

In an advantageous embodiment of the invention, the Operating variables for the current operating point and the current operating mode of the internal combustion engine is determined. It So there are always operating mode and Operating point-dependent operating variables. These farm sizes are in the current, current operation of the internal combustion engine determined and saved.

The realization of the method according to the invention in the form of a control element, that for a control unit of an internal combustion engine, in particular of a motor vehicle is provided. It is on the Control stored a program on a Computing device, in particular on a microprocessor, executable and for executing the invention Process is suitable. In particular, as a control element an electrical storage medium is used, for example a read-only memory or a flash memory.

Figur 1

zeigt ein schematisches Blockschaltbild eines Ausführungsbeispiels einer erfindungsgemäßen Brennkraftmaschine,

Figur 2

zeigt ein schematisches Blockschaltbild eines Ausführungsbeispiels eines erfindungsgemäßen Verfahrens zum Betreiben der Brennkraftmaschine der Figur 1.

Further features, possible applications and advantages of the invention result from the following description of exemplary embodiments of the invention, which are shown in the figures of the drawing. All of the described or illustrated features, alone or in any combination, form the subject matter of the invention, regardless of their summary in the patent claims or their relationship, and regardless of their wording or representation in the description or in the drawing.

Figure 1

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

Figure 2

1 shows a schematic block diagram of an exemplary embodiment of a method according to the invention for operating the internal combustion engine of FIG. 1.

In FIG. 1, an internal combustion engine 1 is one Motor vehicle shown, in which a piston 2 in one Cylinder 3 can be moved back and forth. The cylinder 3 is with a combustion chamber 4 provided, inter alia, by the Piston 2, an intake valve 5 and an exhaust valve 6 is limited. With the inlet valve 5 is an intake pipe 7 and an exhaust pipe 8 is coupled to the exhaust valve 6.

In the area of the inlet valve 5 and the outlet valve 6 protrude an injection valve 9 and a spark plug 10 in the Combustion chamber 4. Fuel can be injected via the injection valve 9 the combustion chamber 4 are injected. With the spark plug 10 the fuel can be ignited in the combustion chamber 4.

In the intake pipe 7 there is a rotatable throttle valve 11 housed, through which the intake pipe 7 air can be supplied is. The amount of air supplied depends on the Angular position of the throttle valve 11 is in the exhaust pipe 8 a catalyst 12 housed, the cleaning of the exhaust gases generated by the combustion of the fuel serves.

An exhaust gas recirculation pipe 13 leads back from the exhaust pipe 8 to the intake pipe 7. In the exhaust gas recirculation pipe 13 is a Exhaust gas recirculation valve 14 accommodated with which the amount of recirculated exhaust gas set in the intake pipe 7 can be. The exhaust gas recirculation pipe 13 and that Exhaust gas recirculation valve 14 form a so-called Exhaust gas recirculation.

One leads from a fuel tank 15 Tank ventilation line 16 to the intake pipe 7. In the Tank vent line 16 is a tank vent valve 17 housed with which the amount of the intake pipe 7th fuel vapor supplied from the fuel tank 15 is adjustable. The tank ventilation line 16 and that Tank vent valve 17 form a so-called Tank ventilation.

The piston 2 is in by the combustion of the fuel the combustion chamber 4 in a reciprocating motion, the is transmitted to a crankshaft, not shown, and exerts a torque on them.

A control device 18 is of input signals 19 acted upon, the operating variables measured by sensors represent the internal combustion engine 1. For example, that is Control unit 18 with an air mass sensor, a lambda sensor, connected to a speed sensor and the like. Of The control unit 18 is also provided with an accelerator pedal sensor connected, which generates a signal that the position of a accelerator pedal operated by a driver and thus that indicates requested torque. The control unit 18 generates Output signals 20 with which via actuators or actuators the behavior of the internal combustion engine 1 can be influenced can. For example, the control unit 18 with the Injector 9, the spark plug 10 and the throttle valve 11 and the like connected and generated to their Control necessary signals.

Among other things, the control unit 18 is provided for the To control operating variables of the internal combustion engine 1 and / or to regulate. For example, that of the injector 9 injected into the combustion chamber 4 fuel mass from the Control unit 18, in particular with regard to a small one Fuel consumption and / or a low Controlled and / or regulated pollutant development. To for this purpose the control unit 18 is equipped with a Microprocessor provided in a storage medium, a program, especially in a flash memory has saved, which is suitable for the named Control and / or regulation to perform.

The internal combustion engine 1 of Figure 1 can in a plurality operated by operating modes. So it is possible that Internal combustion engine 1 in a homogeneous operation, one Shift operation, a homogeneous lean operation, one Shift operation with homogeneous basic charge and the like operate.

In homogeneous operation, the fuel is used during the Intake phase from the injection valve 9 directly into the Combustion chamber 4 of the internal combustion engine 1 is injected. The This means that fuel is largely used until ignition swirls, so that in the combustion chamber 4 an essentially homogeneous fuel / air mixture is created. That too generating moment is essentially about the Position of throttle valve 11 from control unit 18 set. In homogeneous operation, the operating parameters the internal combustion engine 1 controlled and / or regulated that lambda is equal to one. The homogeneous operation is used especially at full load.

The homogeneous lean operation largely corresponds to that Homogeneous operation, however, the lambda becomes one value set greater than one.

In shift operation, the fuel is used during Compression phase from the injection valve 9 directly into the Combustion chamber 4 of the internal combustion engine 1 is injected. In order to is not homogeneous when ignited by the spark plug 10 Mixture present in the combustion chamber 4, but one Fuel stratification. The throttle valve 11 can, apart from of requirements e.g. the exhaust gas recirculation and / or the Tank ventilation, fully open and the Internal combustion engine 1 are operated dethrottled. The torque to be generated is largely in shift operation adjusted over the fuel mass. With the The internal combustion engine 1 can operate in shifts in particular be operated at idle and at partial load.

Between the mentioned operating modes of the internal combustion engine 1 can be toggled back and forth. such Switchings are carried out by the control unit 18. According to FIG. 2, this is in the control unit 18 an operating mode map 21 in which for each Operating point of the internal combustion engine 1 an associated Operating mode is saved.

When the internal combustion engine 1 is operating, it becomes the operating point the internal combustion engine 1 using a Operating state detection device 22 of the Control device 18 determined. This device 22 detects e.g. the speed of the internal combustion engine 1, the engine temperature, the position of the accelerator pedal, and the like. In Dependence on these farm sizes Internal combustion engine 1 is in operation at any time the internal combustion engine 1 the associated operating mode from the Operating mode map 21 read out. Then the Internal combustion engine 1 with the read operating mode, that is e.g. in shift operation or in homogeneous operation or the like, operated.

The operating mode map 21 is used in the production of Internal combustion engines of the same type identical in that Control unit 18 stored. Due to scatter between different internal combustion engines of the same type and due to aging effects, it is possible that those in the operating mode map 21 for the various Operating points stored operating modes in particular a certain duration of the engine 1 not are more optimal.

A method is shown schematically in FIG. with which the operating mode map 21 in the operation of Internal combustion engine 1 are adapted and thus optimized can.

An efficiency detection device 22 determines the Efficiency of the internal combustion engine 1 for the current one Operating point. This can e.g. from the current injected fuel mass and the currently delivered Moment.

The injected fuel mass can from the Injection time and the pressure difference on both sides of the Injector 9 are calculated. The can also Fuel mass with the help of a fuel mass sensor in the associated fuel supply line can be determined. The injection time can be determined from the measurement of the Current course in the final stage of the associated Injector or with the help of an opening duration sensor be determined at the injection valve.

The torque delivered can be measured using a torque sensor determined on the crankshaft of the internal combustion engine 1 become. A combustion chamber pressure sensor can also be provided with the help of which an indexed moment can be calculated is. The torque can also consist of the speed and a Knock signal e.g. of a knock sensor can be determined. Out the delivered torque can then be determined by the speed of the Internal combustion engine 1 whose engine power is calculated.

A smoothness detection device 23 determines the Smooth running engine 1 for the current one Operating point.

This can be done using a speed sensor on the crankshaft and / or combustion chamber pressure sensors in the individual cylinders the internal combustion engine 1 and / or a torque sensor on the Crankshaft and / or an ion current probe can be used. From the output signals of these sensors Speed changes or torque spreading or the like and from this the smoothness of the engine 1 is derived become.

An exhaust gas detection device 24 determines the NOx emissions and / or the HC emissions of the Internal combustion engine 1 for the current operating point.

For this purpose, a NOx sensor and / or an HC sensor in the Exhaust pipe 8 can be used. The NOx components can also in the exhaust gas from the operating parameters of the Internal combustion engine 1, in particular from the operating parameters to control the loading and unloading of the catalyst 12 can be estimated. The HC emissions can also come from the operating variables of the internal combustion engine 1, in particular can be estimated from the smooth running of the same. The NOx, as can the HC emissions from the control unit 18 can also be modeled additionally or alternatively.

The efficiency detector 22, the Smoothness detection device 23 and the Exhaust gas detection device 24 generate parameters for the the current operating point of the internal combustion engine 1. At this operating point, the internal combustion engine 1 in the current operating mode. The The parameters determined are each one certain operating point and a certain operating mode based.

These operating mode and operating point dependent parameters are sent to an operating mode evaluation device 25 passed.

The operating mode evaluation device 25 generates from the available parameters one or more comparison parameters for the respective operating mode. The comparison variable / n will / will be according to given mathematical procedures by linking the entered parameters from the Control device 18 determined.

The operating mode and operating point dependent Comparison variable (s) will then be sent to a Operating mode comparison device 26 passed on.

In the operating mode comparison device 26, the Comparison values for the different operating modes and for the various operating points of the internal combustion engine 1 collected. It is after a certain time Comparative variables available that are based on one and the same Relate operating point of the internal combustion engine 1, but based on different operating modes.

Such comparison variables that have the same operating point, but different operating modes of the internal combustion engine 1 are then compared. From these Comparative quantities will be the optimal based on the comparison Operating mode selected for the current operating point.

This optimal operating mode is then in the Operating mode map 21 for the present operating point the internal combustion engine 1 registered.

It is thus possible to display the operating mode map 21 during the entire duration of the internal combustion engine 1 always adaptively optimize. Scatter between Internal combustion engines of the same type or aging effects Internal combustion engines are thus in operation automatically balanced. The operating mode map 21 is by the method shown in FIG. 2 automatically and continuously optimized so that during the total running time of the internal combustion engine 1 always the optimal operating mode for each operating point in the Operating mode map 21 is stored.

Claims (5)

1. Method for operating an internal combustion engine (1), in which fuel is injected into a combustion chamber (4) in at least two operating modes, in which the engine is switched between the operating modes as a function of an operating-mode characteristic diagram (21), and in which the operating-mode characteristic diagram (21) is adapted as a function of operating variables of the internal combustion engine (1), characterized in that an operating-mode-dependent and operating-point-dependent comparison variable is determined (25) from the operating variables, in that the comparison variables of various operating modes are compared with one another (26) for the same operating point, and in that an optimum operating mode for the operating point is selected as a function of the comparison and is input into the operating-mode characteristic diagram (21).
2. Method according to Claim 1, characterized in that the operating variables determined (22, 23, 24) are the efficiency and/or the running smoothness and/or the exhaust emissions of the internal combustion engine (1).
3. Method according to either of Claims 1 and 2, characterized in that the operating variables for the current operating point and the current operating mode of the internal combustion engine (1) are determined.
4. Control element for a control unit (18) of an internal combustion engine (1), characterized in that a program which is programmed for use in a method according to one of Claims 1 to 3 is stored on the control element.
5. Control unit (18) for an internal combustion engine (1), characterized in that it is designed for use in a method according to one of Claims 1 to 3.

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