DE19941528A1 - Method for operating an internal combustion engine - Google Patents

Abstract

An internal combustion engine (1) of a motor vehicle is described which is provided with a combustion chamber (4) into which fuel can be injected in at least two operating modes. A control device (18) is provided for switching between the operating modes. The control device (18) is provided with an operating mode map. The control unit (18) adapts the operating mode map (21) as a function of operating variables of the internal combustion engine (1).

Description

State of the art

The invention relates to a method for operating a Internal combustion engine, in particular of a motor vehicle, at the fuel in at least two modes Combustion chamber is injected, and depending on from an operating mode map between the operating modes is switched. The invention also relates to a corresponding internal combustion engine and a control unit for such an internal combustion engine.

Such a method, such an internal combustion engine and such a control unit are for example from a so-called gasoline direct injection known. There becomes fuel in a homogeneous operation during the Intake phase or in a shift operation during the Compression phase in the combustion chamber of the internal combustion engine injected. The homogeneous operation is preferably for the Full load operation of the internal combustion engine is provided during shift operation for idle and part-load operation suitable is. For example, depending on one the desired target operating mode is such direct injection internal combustion engine between the mentioned operating modes.

To switch between the operating modes is in the  Control unit provided an operating mode map in which for each operating point of the internal combustion engine associated operating mode is saved. This Operating mode map is the same for internal combustion engines Type in their manufacture identical in the control unit filed.

Are between internal combustion engines of the same type due to tolerances and the like available. Internal combustion engines are also subject during their aging period. As a consequence, that those saved for each operating point Operating modes may not work after a certain time are more optimal for the respective internal combustion engine. However, this means that the respective internal combustion engine is no longer optimally operated.

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

This task is initiated in a procedure mentioned type according to the invention solved in that the Operating mode map depending on operating sizes the internal combustion engine is adapted. At a Internal combustion engine and a control unit of the entry mentioned type, the task according to the invention solved.

The operating mode map is therefore over the entire Running time of the internal combustion engine automatically and continuously optimized. So that the internal combustion engine always operated optimally. By adapting the The operating mode map thus shows variations between Internal combustion engines of the same type as well  Aging effects automatically compensated. By doing Operating mode map are for everyone at any time Operating point of the internal combustion engine the optimal Operating mode saved.

In an advantageous development of the invention efficiency and / or smoothness as operating parameters and / or the exhaust gas emission of the internal combustion engine determined. These company sizes have turned out to be special 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 modes and Operating point-dependent operating variables. These farm sizes are in the current, current operation of the Internal combustion engine determined and stored.

It is particularly advantageous if the operating variables one or more operating mode and operating point dependent Comparative variables are determined. That way it can whole procedure simplified and a subsequent one Comparison will be facilitated.

In an advantageous embodiment of the invention the comparison values for the same operating point different operating modes compared. It So there is a comparison depending on the operating point, in which the comparison variables of the associated, different Operating modes can be compared with each other. With help this comparison can then see the impact of different operating modes in the specific operating point be determined. The effects are  thereby to the above-mentioned operating parameters, e.g. B. um the efficiency and / or the smoothness and / or the Exhaust emissions from the internal combustion engine.

In a further advantageous development of the Invention is a depending on the comparison optimal operating mode selected for the operating point and inscribed in the operating mode map. 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 saved.

This means that the operating mode map is maintained during the entire 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 automatically compensated during operation.

The realization of the inventive method in the form of a Control that for a control unit one Internal combustion engine, in particular a motor vehicle, is provided. Here is on the control Program stored on a computing device, in particular on a microprocessor, executable and for Execution of the method according to the invention is suitable. In this case, the invention is based on a Control program stored so that this control provided with the program in the same The invention represents how the method for its Execution the program is suitable. As a control can in particular be an electrical storage medium for Use, for example, a read-only memory or a flash memory.  

Other features, applications and advantages of the Invention result from the following description of embodiments of the invention shown in the figures the drawing are shown. Thereby everyone described or illustrated features for themselves or in any combination the subject of the invention, regardless of their summary in the Patent claims or their relationship and independently from their formulation or representation in the description or in the drawing.

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

FIG. 2 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 shown a motor vehicle, in which a piston 2 reciprocating in a cylinder 3 and is movable. The cylinder 3 is provided with a combustion chamber 4 , which is delimited inter alia by the piston 2 , an inlet valve 5 and an outlet valve 6 . An intake pipe 7 is coupled to the inlet valve 5 and an exhaust pipe 8 is coupled to the exhaust valve 6 .

In the area of the intake valve 5 and the exhaust valve 6, an injection valve 9 and a spark plug 10 protrude into the combustion chamber 4 . Fuel can be injected into the combustion chamber 4 via the injection valve 9 . The fuel in the combustion chamber 4 can be ignited with the spark plug 10 .

In the intake pipe 7 , a rotatable throttle valve 11 is accommodated, via which air can be fed to the intake pipe 7 . The amount of air supplied is dependent on the angular position of the throttle valve 11 . A catalytic converter 12 is accommodated in the exhaust pipe 8 and serves to clean the exhaust gases resulting from the combustion of the fuel.

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

A tank ventilation line 16 leads from a fuel tank 15 to the intake pipe 7 . In the tank ventilation line 16 , a tank ventilation valve 17 is accommodated, with which the amount of fuel vapor supplied to the intake pipe 7 from the fuel tank 15 can be adjusted. The tank ventilation line 16 and the tank ventilation valve 17 form a so-called tank ventilation.

The combustion of the fuel in the combustion chamber 4 causes the piston 2 to move back and forth, which is transmitted to a crankshaft (not shown) and exerts a torque thereon.

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

Among other things, the control unit 18 is provided to control and / or regulate the operating variables of the internal combustion engine 1 . For example, the fuel mass injected into the combustion chamber 4 by the injection valve 9 is controlled and / or regulated by the control unit 18, in particular with regard to low fuel consumption and / or low pollutant development. For this purpose, the control unit 18 is provided with a microprocessor, which has stored a program in a storage medium, in particular in a flash memory, which is suitable for carrying out the control and / or regulation mentioned.

The internal combustion engine 1 of FIG. 1 can be operated in a plurality of operating modes. It is thus possible to operate the internal combustion engine 1 in a homogeneous operation, a stratified operation, a homogeneous lean operation, a stratified operation with a homogeneous basic charge and the like.

In homogeneous operation, the fuel is injected from the injection valve 9 directly into the combustion chamber 4 of the internal combustion engine 1 during the intake phase. As a result, the fuel is largely swirled until it is ignited, so that an essentially homogeneous fuel / air mixture is produced in the combustion chamber 4 . The torque to be generated is essentially set by the control unit 18 via the position of the throttle valve 11 . In homogeneous operation, the operating variables of internal combustion engine 1 are controlled and / or regulated in such a way that lambda is equal to one. Homogeneous operation is used particularly at full load.

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

In stratified operation, the fuel is injected from the injection valve 9 directly into the combustion chamber 4 of the internal combustion engine 1 during the compression phase. This means that when the spark plug 10 is ignited, there is no homogeneous mixture in the combustion chamber 4 , but rather a fuel stratification. The throttle valve 11 can, apart from requirements such. B. the exhaust gas recirculation and / or the tank ventilation, fully opened and the engine 1 can be operated dethrottled. The torque to be generated in shift operation is largely set via the fuel mass. With the stratified operation, the internal combustion engine 1 can be operated in particular at idle and at partial load.

It is possible to switch back and forth or toggle between the aforementioned operating modes of the internal combustion engine 1 . Such switching operations are carried out by the control unit 18 . According to FIG. 2, an operating mode map 21 is present in the control unit 18 , in which an associated operating mode is stored for each operating point of the internal combustion engine 1 .

During operation of the internal combustion engine 1 , the operating point of the internal combustion engine 1 is determined by the control unit 18 with the aid of an operating state detection device 22 . This device 22 detects z. B. the speed of the internal combustion engine 1 , the engine temperature, the position of the accelerator pedal, and the like. Depending on these operating variables of the internal combustion engine 1, the associated operating mode is read out from the operating mode map 21 at every point in time when the internal combustion engine 1 is operating. Then the internal combustion engine 1 with the read operating mode, that is, for. B. in shift operation or in homogeneous operation or the like, operated.

The operating mode map 21 is stored identically in the control unit 18 when manufacturing internal combustion engines of the same type. Due to scatter between different internal combustion engines of the same type and due to aging effects, it is possible that the operating modes stored in the operating mode map 21 for the different operating points are no longer optimal, in particular after a certain running time of the internal combustion engine 1 .

In FIG. 2, a method is schematically illustrated, which adapts the mode map 21 in the operation of the internal combustion engine 1 and can be optimized.

An efficiency detection device 22 determines the efficiency of the internal combustion engine 1 for the current operating point. This can e.g. B. derived from the currently injected fuel mass and the currently delivered torque.

The injected fuel mass can be calculated from the injection time and the pressure difference on both sides of the injection valve 9 . The fuel mass can also be determined with the aid of a fuel mass sensor in the associated fuel supply line. The injection time can be determined from the measurement of the current profile in the output stage of the associated injection valve or with the aid of an opening duration sensor on the injection valve.

The torque delivered can be determined with the aid of a torque sensor on the crankshaft of the internal combustion engine 1 . A combustion chamber pressure sensor can also be provided, with the aid of which an indexed torque can be calculated. Likewise, the torque from the speed and a knock signal z. B. a knock sensor can be determined. The engine output can then be calculated from the output torque using the speed of the internal combustion engine 1 .

A smooth running detection device 23 determines the smooth running of the internal combustion engine 1 for the current operating point.

For this purpose, a speed sensor on the crankshaft and / or combustion chamber pressure sensors in the individual cylinders of 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 scattering or the like and the smooth running of the internal combustion engine 1 can be derived therefrom.

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 fractions in the exhaust gas can also be estimated from the operating variables of the internal combustion engine 1 , in particular from the operating variables for controlling the loading and unloading of the catalytic converter 12 . The HC emissions can also be estimated from the operating variables of the internal combustion engine 1 , in particular from the smooth running thereof. The NOx as well as the HC emissions can also be modeled additionally or alternatively by the control unit 18 .

The efficiency detection device 22 , the smooth running detection device 23 and the exhaust gas detection device 24 generate parameters for the current operating point of the internal combustion engine 1 . At this operating point, the internal combustion engine 1 is operated in the current operating mode. The parameters determined are thus related to a specific operating point and a specific operating mode.

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

The operating mode evaluation device 25 generates one or more comparison variables for the respective operating mode from the present parameters. The comparison variable (s) is / are determined by the control unit 18 according to predetermined mathematical methods by linking the input parameters.

The operating mode-dependent and operating point-dependent comparison variables are then passed on to an operating mode comparison device 26 .

The comparison variables for the various operating modes and for the various operating points of the internal combustion engine 1 are collected in the operating mode comparison device 26 . After a certain time, there are therefore comparison variables which relate to one and the same operating point of the internal combustion engine 1 , but which are based on different operating modes.

Such comparison variables which relate to the same operating point but different operating modes of the internal combustion engine 1 are then compared with one another. Based on the comparison, the optimal operating mode for the present operating point is selected from these comparison variables.

This optimal operating mode is then written into the operating mode map 21 for the present operating point of the internal combustion engine 1 .

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

Claims (9)

1. A method for operating an internal combustion engine ( 1 ), in particular a motor vehicle, in which fuel is injected into a combustion chamber ( 4 ) in at least two operating modes, and in which a switch is made between the operating modes as a function of an operating mode map ( 21 ), characterized in that that the operating mode map ( 21 ) is adapted as a function of operating variables of the internal combustion engine ( 1 ). 2. The method according to claim 1, characterized in that the efficiency and / or the smoothness and / or the exhaust gas emission of the internal combustion engine ( 1 ) are determined as operating parameters ( 22 , 23 , 24 ). 3. The method according to any one of claims 1 or 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. The method according to any one of claims 1 to 3, characterized in that a comparison variable dependent on the operating mode and operating point is determined from the operating variables ( 25 ). 5. The method according to claim 4, characterized in that the comparison variables of different operating modes are compared ( 26 ) for the same operating point. 6. The method according to claim 5, characterized in that, depending on the comparison, an optimal operating mode is selected for the operating point and is written into the operating mode map ( 21 ). 7. Control element, in particular read-only memory or flash memory, for a control device ( 18 ) of an internal combustion engine ( 1 ), in particular a motor vehicle, on which a program is stored which can be run on a computing device, in particular on a microprocessor, and for Execution of a method according to one of claims 1 to 6 is suitable. 8. Internal combustion engine ( 1 ), in particular of a motor vehicle, with a combustion chamber ( 4 ) into which fuel can be injected in at least two operating modes, and with a control unit ( 18 ) with an operating mode map ( 21 ) for switching between the operating modes, characterized in that the operating mode map ( 21 ) can be adapted as a function of operating variables of the internal combustion engine ( 1 ) by the control device ( 18 ). 9. Control device ( 18 ) for an internal combustion engine ( 1 ), in particular of a motor vehicle, the internal combustion engine ( 1 ) being provided with a combustion chamber ( 4 ) into which fuel can be injected in at least two operating modes, and the control device ( 18 ) for switching over between the operating modes is provided with an operating mode map ( 21 ), characterized in that the control unit ( 18 ) can adapt the operating mode map ( 21 ) as a function of operating quantities of the internal combustion engine ( 1 ).