KR20180088709A - Method and apparatus for operating an internal combustion engine of a vehicle, particularly a dual fuel injection system - Google Patents

Abstract

The present invention relates to a method and apparatus for operating an internal combustion engine having a double-fuel metering section and a direct fuel metering section based on a suction pipe, wherein the amount of fuel required for fuel metering based on the suction pipe and for direct fuel metering, respectively, (440), the internal combustion engine has an exhaust gas recirculation means (560), and the residual gas formed by the exhaust gas recirculation means during combustion is exhausted through the inlet channel (535) of the suction pipe (505) Is supplied to the engine and in particular to the interior of the inlet channel 535 of the suction pipe 505 is fed metered fuel with the heat of the recirculated residual gas and is supplied to the inlet of the suction pipe 505 which is caused by the heat of the recirculated residual gas In accordance with the temperature rise of the metered fuel into the inlet channel 535, the fuel distribution is moved toward the proportionally higher intake pipe-based fuel metering (440).

Description

Method and apparatus for operating an internal combustion engine of a vehicle, particularly a dual fuel injection system

The present invention relates to a method and an apparatus for operating an internal combustion engine of a motor vehicle, in particular a dual fuel metering system, according to the preamble of the respective independent claims. Still another object of the present invention is a computer program, a machine readable data storage medium for storing a computer program, and an electronic control device capable of performing the method according to the present invention.

In the case of dual fuel metering in connection with the present application, the suction pipe injection method and the direct injection method are combined or executed in parallel during the fuel metering of the internal combustion engine. In practice, such an internal combustion engine can be formed as a dual system, and in a dual system mixing mode, the fuel is supplied to the internal combustion engine by the intake pipe injection system (SRE) and by the fuel direct injection system (BDE) Can be supplied simultaneously to the cylinder. In this case, the dispense amount indicates the amount of fuel that can be supplied to the cylinder by the suction pipe injection method and the fuel distribution to another amount of fuel that can be supplied to the cylinder by the fuel direct injection method.

For example, DE 10 2010 039 434 A1 discloses that the distribution amount of the internal combustion engine in the above-described mixed mode is determined in consideration of an operating point such as load and / or revolution number. Thus, such a blending mode makes it possible to carry out the operation of the internal combustion engine optimal for different operating conditions, by the amount of each of them being realized as intended. Utilizing the advantages of the two injection methods, optimum mixture formation and combustion are possible. Therefore, the BDE is desirable in a dynamic operating mode or an operating mode under full load of the internal combustion engine, because the known "knocking" can be prevented. On the other hand, in the case of the SRE, the exhaust gas load by particles and / or hydrocarbons (HC) is preferably reduced in the partial load mode of the internal combustion engine because the intake pipe length leads to better mixture formation Because.

Also known is an internal combustion engine in which the residual gas formed during combustion is newly supplied by the exhaust gas recirculation means (EGR) of the internal combustion engine. In this case, when the intake valve and the discharge valve are simultaneously opened after the combustion and remain in the top dead center space of the individual cylinders, the internal residual gas which is sucked back into the aforementioned suction pipe and flows into the individual combustion chamber again in the subsequent expansion stroke Exhaust gas recirculation) and the external residual gas (external exhaust gas recirculation) introduced into the suction pipe through the exhaust gas recirculation valve are distinguished from each other. The residual gas consists of an inert gas and consists of unburned air in a lean mode, i.e. in the case of excess air. The inert gas ratio slows the combustion process, thereby causing a lower combustion final temperature. As a result, the release of nitrogen oxides (NOx) may be reduced by the residual gas ratio. In this case, it may occur that the three-way catalytic converter can not reduce nitrogen oxides in principle in the event of excess air.

Also, in the intake stage of the internal combustion engine, so-called "throttling loss" also occurs when the suction pipe pressure is lower than the ambient pressure, and in particular the pressure in the piston backspace, This is because they must work against each other. Furthermore, when the rotational speed and the load are high, a back pressure is generated when the combustion gas is discharged during upward movement of the piston in the combustion chamber, so-called "exhaust loss" The throttling loss described above is advantageous in the BDE mode, more precisely in the presence of a shift mode when the throttle valve is open and thus excessively over-air, or in the presence of a fuel vapor / air ratio or a corresponding In a homogeneous mode with a lambda value, the frequency of use of the exhaust gas recirculation can be reduced by increasing or increasing, since in this case the suction pipe pressure is higher and therefore the pressure difference applied to the piston is correspondingly smaller .

The present invention relates to an internal combustion engine having an internal and / or external exhaust gas recirculation means (EGR), a method for distributing fuel during dual fuel metering in accordance with the present invention, and a corresponding apparatus. The present invention is based on the recognition that the fuel introduced into the intake channel in the SRE mode is relatively poorly evaporated in a state where the internal combustion engine has not yet reached the operating temperature, for example, during startup of the internal combustion engine or in the startup phase, This situation again leads to a fuel sedimentation effect or fuel reserve storage effect and thus an increase in the rate of unburned hydrocarbons in the exhaust gas. Correspondingly, and also in the BDE mode, the fuel directly introduced into the combustion chamber is relatively poorly evaporated, which in turn leads to the wetting of the combustion chamber surface by the fuel, resulting in a reduction in the number of particles in the exhaust gas .

The present invention is also particularly advantageous in the case of a dynamic load change to a higher load, for example a fast load change from a low load to a high load, i.e. in the so-called "transient mode & If the internal combustion engine or combustion chamber, piston, etc. are still too cold, it is based on another recognition that fuel accumulates on the surface of the combustion chamber. Thereby, it takes a certain time until the combustion chamber surface including the piston surface takes a new or higher load point temperature. The liquid film formed by accumulation does not evaporate sufficiently quickly and is not completely burned for this reason, which results in the formation of an increased particle concentration in the exhaust gas and / or a solid precipitate in the relevant parts. This can cause the functions of the parts to be impaired or even compromised. On the other hand, direct measurement of the temperature of the combustion chamber or piston is difficult, as is known, or only possible with considerable technical complexity and associated costs.

The fact to mention is that the problem of fuel accumulation from the above-mentioned higher load point to lower load point is not raised.

In the proposed method according to the invention, the enthalpy of exhaust gas recirculated into the intake system of the internal combustion engine through the above-mentioned EGR, or the enthalpy of the exhaust gas recirculated into the intake system of the internal combustion engine, It is based on the idea of using heat capacity. By doing so, when the inlet channel is still cold in the starting phase of the internal combustion engine, or because the piston and / or combustion chamber surface is still too cold for a higher load due to the transient operating mode of the internal combustion engine, Can be moved toward higher SRE fuel metering. By such movement, the amount of unburned hydrocarbons in the exhaust gas and the exhaust gas is remarkably reduced again.

Furthermore, the above movement can prevent the oil lubricant film in the cylinder sliding bushing, which is caused by the reduced BDE mode in the above-mentioned critical operating condition, to be reduced or even avoided, This situation effectively reduces the wear of, for example, the piston ring and the cylinder sliding bushing again.

The method according to the invention is particularly advantageous in the dual fuel metering in connection with the present invention using exhaust gas recirculation means which allows the residual gas formed during combustion to be newly supplied to the internal combustion engine through the intake channel of the intake pipe, In a manner such that the fuel distribution is shifted to the injected fuel toward the intake pipe-based fuel metering proportionally higher as the temperature of the fuel injected into the inlet channel of the intake pipe increases due to the heat of the recirculated residual gas, And the heat of the residual gas is supplied.

At this time, if the internal combustion engine is perceived as being in the cold start phase, or if the internal combustion engine is perceived as being in a transient mode from a lower load to a higher load, then the fuel distribution is directed toward a proportionally higher intake- Can be moved.

Further, when the cold start phase is recognized, preferably the following group

The temperature of the intake channel of the internal combustion engine;

- ambient temperature;

- the temperature of the internal combustion engine;

- the oil temperature of the internal combustion engine;

A temperature selected from the piston temperature determined with reference to the model calculations is detected and the maximum fuel quantity for the suction pipe based fuel metering (SRE) is determined according to the detected temperature and the maximum fuel quantity for direct fuel metering (BDE) The possible amount of fuel is determined and the total amount of fuel to be metered is compared with the determined amount of fuel and the amount of excess fuel that is generated in some cases according to the comparison result is converted by the corresponding amount increase of the metered fuel through the intake pipe- .

The fact to be mentioned in this section is that in order to determine whether the total fuel metering during the combustion chamber heating should be by an increased intake-pipe-based fuel metering (SRE) or by an increased direct fuel metering (BDE) Temperature is important. The reason is that in order to make the piston less wet by the (deposited) fuel-liquid film formed as described in the BDE mode, more parts should be metered on the suction tube basis (SRE) if the piston is relatively cold .

In this application, referring to the fuel wall film model, how much fuel is deposited in the liquid state inside the wall of the suction pipe, how much fuel is transferred from the wall film into the combustion chamber in liquid form by mass flow of the intake air from the wall film, In which case the degree of fuel evaporation due to the intake air and / or the air / exhaust gas mixture resulting from the fuel wall membranes can be determined according to the temperature and thermal enthalpy of the intake pipe and also on the basis of the intake air and / Is estimated based on the temperature and the heat enthalpy of the exhaust gas mixture.

Also, with reference to the piston temperature model and / or the combustion chamber wall temperature model, it can be determined whether the heat stored in the piston of the internal combustion engine and / or in the combustion chamber wall is sufficient for the deposited fuel film to evaporate or combust in time during combustion of the fuel have.

The last two mentioned model calculations can further improve the feasibility or operational safety of the method according to the invention and consequently the exhaust gas value mentioned above.

If no cold starting phase is detected, it can be checked whether there is a transient operating state of the internal combustion engine. If a transient operating state is detected, the fuel ratio metered through the intake pipe-based fuel metering can be directly Relative to the metered fuel.

Further, in order to further enhance the aforementioned thermal effect or heat introduction and thus the evaporation effect described above, an appropriate speed increase of the exhaust gas recirculation means can be additionally performed in accordance with the above-described comparison result. When such an EGR rate rises, the filling pressure and the control time of the individual inlet valve (s) are also adjusted to ensure the necessary fresh air charging process, which is dependent on the individual operating point of the internal combustion engine.

By the use of the enthalpy or heat capacity described above, i.e. by the use of additional heat introduction into the intake system provided for fuel evaporation in the SRE mode due to exhaust gas recirculation, the adaptation of the distribution factor in the SRE mode direction or Movement becomes possible. As a result, improved mixture processing becomes possible in the cold start phase of the internal combustion engine or in the warm-up phase and / or in the transient mode of the internal combustion engine described above.

The fuel distribution can also be determined on the basis of the measured or calculated temperature of the at least one piston of the internal combustion engine, in which case if the transient mode of operation is perceived or detected as an increase in the temperature of the one or more pistons of the internal combustion engine, The amount of fuel metered by metering is continuously increased, and the amount of fuel metered by the intake pipe based fuel metering is continuously reduced. In this case, it is based on the recognition that the effect of the piston temperature on the fuel accumulation effect and / or the fuel evaporation effect or the fuel removal effect described above is considerably large.

As a result, as a result, in addition to the mixing mode having a fixed mixing ratio, in the above-mentioned (preceding) operation stage of the internal combustion engine, the dynamic mode in which the mixing ratio of the two fuel metering systems changes during operation of the internal combustion engine in the above- Variable mixing mode is possible. The calculation of the metered fuel, which is required for this purpose through the two fuel metering paths, is preferably controlled with reference to the above mentioned temperature value or with reference to the threshold value.

By adaptation or movement of the proposed distribution factors, the method according to the invention can be used in the cold start of the associated internal combustion engine by means of a double fuel metering and / or in the transient mode The fuel evaporation of the fuel / air mixture and the associated mixture treatment provided for combustion can be improved compared to the prior art.

The present invention is particularly applicable to dual fuel injection systems related to the present application of automotive internal combustion engines. Further, the present invention can be applied in an industrial field, for example, an internal combustion engine having a dual fuel injection system as described above and used in a chemical method technology.

The computer program according to the present invention is designed to perform each step of the method, particularly when the computer program is implemented on a computer or a control device. Such a computer program enables the implementation of the method according to the present invention on an electronic control device without the necessity of implementing a structural change in the electronic control device. To this end, there is provided a machine-readable data storage medium in which a computer program according to the present invention is stored. By implementing a computer program according to the invention on an electronic control device, an electronic control device according to the present invention, which is designed to control the dual fuel metering associated with this invention using the method according to the invention, is obtained.

Other advantages and embodiments of the present invention will be apparent from the following detailed description and the accompanying drawings.

It is to be understood that the features which have been described above and which will be described further below may be used in other combinations as well as individually or in combination, without departing from the scope of the present invention.

1 is a schematic view of a dual fuel injector for a four-cylinder internal combustion engine according to the prior art.
Figure 2 shows a sequence over time of fuel injection in a fuel-intake pipe injection system, in accordance with the prior art.
Figure 3 shows a sequence over time of fuel injection in a fuel-direct injection mode, according to the prior art.
4 is a flow diagram of one embodiment of a method according to the present invention.
5 is a diagram showing an exhaust gas recirculation system of an external ignition type internal combustion engine according to the prior art to which the method according to the present invention can be applied or can be used.

The internal combustion engine shown in Fig. 1 has four cylinders 11 covered by one cylinder head 12. As shown in Fig. The cylinder head 12 restricts the combustion chamber 13 in each cylinder 11 together with the stroke piston which is not shown in the figure and is guided in the cylinder 11, Which is also controlled by an inlet valve, not shown in the drawing. In this case, the inlet opening passes through the cylinder head 12 and forms the inlet of the inlet channel which is likewise not shown in this figure.

The illustrated fuel injection device includes an air flow path 18 for supplying combustion air to the combustion chamber 13 of the cylinder 11, (17). A first group of fuel injection valves 19 for injecting fuel directly into each one combustion chamber 13 of the cylinder 11 and a second group of fuel injection valves 19 for injecting fuel into the flow channel 17 20 are disposed.

A first group of fuel injection valves 19 that directly inject into the cylinder 11 are connected to a second group of fuel injection valves 20 that receive fuel from the fuel high pressure pump 21 and into the flow channel 17, Pressure fuel pump 22 is supplied with fuel. In this case, the fuel low-pressure pump, which is usually disposed in the fuel tank 23, feeds the fuel derived from the fuel tank 23 to the fuel injection valve 20 of the second group on one side and fuel high- To the pump (21). The injection timing and injection period of the fuel injection valves 19 and 20 are controlled by the electronic control unit integrated in the engine control unit according to the operating point of the internal combustion engine, And a second group of fuel injection valves 20 are provided for improving the non-permissiveness of fuel direct injection by the first group of fuel injection valves 19 within a certain operating range, Of the degree of freedom or injection strategy.

The second group of fuel injection valves 20 are formed as multi-jet injection valves, and such multi-jet injection valves are commonly used in the form of a spray cone, Is configured to be disposed in the air flow path 18 so that the jets 24 and 25 reach the various flow channels and are angularly displaced relative to each other and simultaneously emit two or more separate fuel jets. In such an internal combustion engine, two double jet injection valves 26 and 27 are provided, and these injection valves are arranged in such a manner that one double jet injection valve 26 is connected to the first and second cylinders 11 Is arranged in the air flow path (18) so as to be injected into the channel (17) and into the flow channel (17) in which the second double jet injection valve (27) is guided to the third and fourth cylinders have. To this end, the flow channel 17 is formed such that there is a mounting point for the dual jet injection valve 26 or 27 between the two directly adjacent flow channels 17.

It is also known that, in the above-described fuel-suction pipe injection system of the internal combustion engine related to the present invention, the air / fuel mixture is generated outside the combustion chamber in the suction pipe. At this time, the individual injection valve injects the fuel in front of the intake valve, in which case the mixture in the intake pipe is introduced into the combustion space by the open intake valve. Fuel supply is accomplished by a fuel delivery module that delivers the required amount of fuel from the tank to the injection valve at a specified pressure. The air control is performed so that the internal combustion engine supplies the correct air mass at each operating point. The injection valve placed in the fuel allocator meters the desired amount of fuel precisely into the airflow. The above-described engine control device adjusts the required air / fuel mixture based on the torque as the center reference variable, respectively. Effective exhaust gas cleaning is achieved by lambda control, which always controls the stoichiometric air / fuel ratio (lambda = 1).

By contrast, in the fuel-direct injection mode, the air / fuel mixture is formed directly in the combustion chamber. At this time, fresh air is introduced through the aforementioned inlet valve, in which case the fuel is injected into the air flow at a high pressure (within a range of 300 bar or more). This situation enables optimal turbulence formation of the air / fuel mixture and improved cooling of the combustion chamber.

It is also known in the four-cylinder internal combustion engine (Auto Engine) that the driving cycle includes processes such as suction, compression, expansion and exhaust, in which each cylinder moves up and down two times, Stop at point (OT) and two bottom dead center (UT). The crankshaft performs two rotations in one driving cycle, and the camshaft performs one rotation. The ignition of the air / fuel mixture supplied into the cylinder is made at the point of time at which the mixture has just been compressed. Such a case is referred to as ignition-zero (ZOT). On the other hand, there is also a cross-OOT (UEOT) in which not only the inlet valve but also the outlet valve are opened when moving from exhaust to suction.

On the contrary, immediately after starting, ignition is carried out at all the top dead centers OT in one or more cylinders, in this case at the specific top dead center, especially at every second OT, at the crankshaft angle of 720 DEG, . Depending on whether the air / fuel mixture is actually ignited at the top dead center OT where the ignition timing shift is performed or at a crankshaft angle shifted by 360 degrees, a reduction in the physical operation in the individual cylinder can be ascertained .

In Fig. 2, the y-direction suction pipe injections at various rotational speeds of the internal combustion engine are shown above the crankshaft angle KW measured in units of degrees. The four-cylinder combustion cycle according to the auto-engine principle includes a first bottom dead center UT1, a first top dead center OT, another bottom dead center UT2, and another top dead center UT2, Lt; RTI ID = 0.0 > ZOT. ≪ / RTI >

The aforementioned temporal reference marks are provided very differently for the two injection paths. Therefore, in the suction pipe injection system SRE as schematically shown in Fig. 2, in the injection 200 which is performed only at, for example, four different rpm (n = 1000, 2000, 4000 and 7000 U / min) A certain time delay portion 205 to be indicated before the end 210 of the cycle 225 is considered because in the case of the SRE the injection valve is disposed outside the individual combustion chamber of the internal combustion engine, The inside of the combustion chamber is forced to reach the inside of the combustion chamber only from the injection position. This additional time demand varies as the number of revolutions of the internal combustion engine changes or increases, as can be seen in Fig. Hence, the injection is correspondingly earlier controlled, for example at a rate of 7000 U / min, even after the ignition on the preceding ZOT 220, in order to provide a constant time demand 205 at all rpm It is also controlled before the placed UT1. The overall time injection window for the illustrated injection cycle corresponds to parentheses 225 described in the drawings as already mentioned above. The next ZOT following the preceding ZOT 220 is denoted 215.

On the other hand, in the gasoline direct injection system (BDE), in the individual injection 300, the (specific) angular mark is empirically determined in advance as a reference mark, as schematically shown in Fig. In other words, unlike the SRE, in the BDE, a constant time portion is not taken into account, as can be seen, for example, from the individual injection end waveform 305. Hence, in this case the injections can be made near the ignition event of the ZOT 315, and for this reason are calculated at a later time correspondingly. In this example, ignition at the subsequent ZOT 315 occurs after the end 310 of the illustrated injection cycle 325. The ignition timing preceding the ZOT 315 is performed in the preceding ZOT 320. [

Typically, the exhaust gas consisting of a combusted fuel vapor / air mixture is now particularly composed of water vapor and carbon dioxide (CO ₂ ). As a result, the heat capacity of the exhaust gas is remarkably increased as compared with the ambient air. Therefore, the hot exhaust gas, which is guided into the intake pipe of the internal combustion engine by the exhaust gas recirculation means, supplies a relatively high heat flow to the intake channel. This heat flow again ensures that the suction tube inner wall is quickly heated to an already high temperature level, especially at the start-up stage of the internal combustion engine.

By means of the SRE injection process, a large part of the metered fuel is also provided on the inner surface of the suction pipe. The warmer the internal surface, the more rapidly the evaporated fuel enters the so-called "mixture treatment ", that is to say the better mixing of the fuel vapor, the air and the recirculated exhaust gas.

In the dual system mentioned in the preamble, the two parts described, SRE part and BDE part, are combined in the form of system or system components as is known. In this case, an exact distribution of the total fuel quantity to be supplied or to be metered in particular is required. The total fuel amount (KM _ges ) for one cylinder is given by the following equation

Where KM _SRE describes the relative fuel mass of the SRE path and KM _BDE describes the relative fuel mass of the BDE path. The corresponding process sequence for calculating or distributing the required fuel mass during injection in such a dual system is described with reference to the flow chart shown in Fig.

After the start 400 of the routine shown in this embodiment, it is first checked 405 whether the internal combustion engine is in the cold start phase or not yet heated to the operating temperature. If the condition is not satisfied, it is checked whether the internal combustion engine continues to operate from a lower load to a higher load in the transient mode described above (407). If the two conditions 405 and 407 are not met, the routine ends (410).

If the check step 405 results in a cold start step, one or more temperature values are first detected (415) by a known sensor device, more precisely the following group:

The temperature of the intake channel of the internal combustion engine;

- ambient temperature;

- the temperature of the internal combustion engine;

- the oil temperature of the internal combustion engine;

- the piston temperature determined with reference to the model calculations.

Based on the detected temperature value 415 as described above, the maximum fuel quantity for the SRE mode is determined 420 and such maximum fuel quantity induces sufficient evaporation of the fuel metered in the SRE mode continuously at the current temperature . In this case, referring to the fuel wall film model, how much fuel is deposited in the liquid state into the wall of the suction pipe and how much fuel is discharged into the combustion chamber from the wall film by the mass flow of the intake air into the combustion chamber and by evaporation It is determined whether the gas is discharged into the combustion chamber from the wall film. In this case, the degree of fuel evaporation by the intake air from the fuel wall film and / or by the air / exhaust gas mixture is dependent on the temperature and thermal enthalpy of the intake pipe and on the temperature and the thermal enthalpy of the intake pipe and / Respectively.

For the above-mentioned evaporation of the fuel in the suction pipe wall, the following parameters are mainly determined: the intake pipe temperature, the intake air temperature, the gas density, the degree of turbulence and the flow rate of the air flow and also the engine speed and the above- The valve control time of the valve is related. The reason is that the higher the degree of turbulence and the flow velocity in the suction pipe, the more the fuel adhering to the wall can be evaporated so much, and the less the amount of fuel accumulated or stored in the wall film.

In addition, the limit of fuel deposition in the wall is calculated, which does not yet cause an undesired fuel reserve storage effect. It is to be noted that, in the case of the fuel preliminary storage, the amount of liquid fuel detected in a place directly connected to the inlet valve is handled, unlike the case where fuel is accumulated to form a wall film. With reference to the interval of the present value of fuel accumulation to the above maximum limit of fuel accumulation, the amount by which the intake pipe injection quantity can be increased is calculated, and this situation includes the shift of the injection quantity division from the direct injection to the intake pipe injection do.

In addition, the amount of fuel that can be supplied at maximum in the BDE mode is determined (425), which in turn leads to acceptable particle emissions. In this case, in this embodiment, referring to the piston temperature model and / or the combustion chamber wall temperature model, it is assumed that the heat stored in the piston or in the combustion chamber wall causes the accumulated fuel film, which wet the piston bowl or the combustion chamber wall, It is determined whether it is sufficient to evaporate or burn in time. In other cases, during subsequent evaporation and subsequent combustion, undesirable particle formation in the exhaust gas due to lack of oxygen after the main combustion is induced, leading to coating formation and coke formation, for example, at the combustion chamber surface, such as the piston surface .

Thus, a sudden change from a lower load point to a higher load point in a conventional manner causes an increase in the injection quantity and an increase in the combustion temperature. In such a sudden change of load, for example, the piston continues to be at a previous or lower temperature level due to thermal inertia, thereby further enhancing the accumulation effect described above, particularly when the piston is at its final temperature ≪ / RTI >

Now, for example, 430 transferred from the control unit, the total fuel quantity to be metered or injected is compared with the two maximum amounts described above (435). If the comparison 435 indicates that the total amount of fuel 430 to be metered is greater than the sum of the two maximum amounts, then the corresponding excess fuel amount is converted by the amount of fuel 440 that is metered in the SRE mode, By an appropriate speed increase 445 of the external EGR recirculation means which can also reliably evaporate said additional fuel quantity metered by said EGR recirculation means.

In this case, the technical effect is that the recirculated exhaust gas has a high thermal enthalpy due to the high temperature and the contained water vapor, which causes the heating of the suction tube surface and the fuel vapor / air mixture. Such an effect again causes improved evaporation of the liquid fuel (e.g., so-called barrier film and / or fuel spray) accumulated in the suction channel. If the above-mentioned relative increase of the intake pipe injection amount with respect to the total fuel amount to be injected is not sufficient for this, the exhaust gas recirculation speed may be increased, thereby again causing more intake pipe injection amount to evaporate. Depending on the corresponding injection duration of the suction pipe injection valve, the opening time and / or stroke of the inlet valve can also be enlarged.

The above-described models describe the underlying physical relationships, for example, using parameterized general formulas and / or characteristic curve / characteristic maps or using numerical methods (e.g., the well-known Gaussian method). In this case, the corresponding parameter and characteristic curve / characteristic map can be digitized in the preceding process in the inspection zone. The above-described numerical model can be trained, for example, by referring to a desired output characteristic of one or a plurality of output variables of an input variable to be influenced. The model data trained in this manner can be stored in the control device, and an individual model for the run time of the internal combustion engine or the vehicle can be calculated based on the model data.

The fact to be mentioned is that, for example, in an operating state or operating state in which the piston temperature continuously increases after a sudden change in load, the amount of BDE participating in the total metering continuously increases to the target value, and that the SRE amount and / or the exhaust gas recirculation speed Is continuously decreased to the target value. These target values correspond to the fuel amount distribution values stored in the characteristic map correspondingly to the stopping operation of the internal combustion engine and correspondingly applied after the end of the piston heating step as described above.

Another fact to mention is that the abovementioned amount of increase 440 is preferably made by adaptation or alteration of the abovementioned amount of distribution or distribution factor.

Now, if the above-mentioned transient operating state of the internal combustion engine is detected when the cold start step is not detected or does not exist in the above-described inspecting step 407, the amount of heat present in the suction pipe is changed in the SRE mode Unless additionally sufficient to vaporize the metered fuel, the metered fuel ratio through the SRE mode is increased relative to the BDE mode, and the external EGR recycle rate is likewise increased in the manner described (445).

A further fact to mention is that the flow chart shown in Fig. 4 must still be applied, for example when the piston is heated in the above-described transient mode and when a positive load sudden change (sudden change from a small load to a large load) In the case of applying the method described with reference to Fig. 4, the aforementioned EGR measures and / or the above-mentioned increased SRE injection must be repeatedly reduced or decreased again.

In the EGR system shown in Fig. 5 where the described method can be applied, air and fuel vapors are supplied to the suction pipe 505 through the supply line 500, as is known. The end 510 of the feed line 500 is connected to a known fuel vapor suppression system (not shown in this figure). In the supply line 500, a regeneration valve 515 having a variable valve-opening cross-section is disposed.

In the suction pipe 505, there is a throttle valve 520 as known in the art. By this throttle valve, the air supplied to the combustion chamber 525 of the internal combustion engine can be adjusted through the setting angle a. Therefore, the throttle valve 520 in front of the air with the ambient pressure (p _U) to which the air mass flow 530, placed with, intake pipe pressure (p _S) in the region after the throttle valve 520 in the inlet channel (535) A mass flow is in place. The cylinder of the internal combustion engine shown in this figure has a piston 540 and an inlet valve 545 and an outlet valve 550 as is well known. The exhaust gas discharged through the discharge valve 550 is guided to a known exhaust gas line (not shown) through the exhaust channel 565.

An exhaust gas recirculation line (EGR line) 560 is disposed between the exhaust channel 565 and the intake channel 535. The recirculated exhaust gas is introduced into the combustion chamber 525 or the combustion section . The recirculation rate or EGR rate may be controlled by an exhaust gas recirculation valve (EGR valve) 555 having a variable valve opening cross section, or may be open circuit or closed circuit controlled.

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

Claims (15)

A method for operating an internal combustion engine having a dual fuel metering section and a direct fuel metering section based on a suction pipe, the method comprising the steps of: (440) calculating a fuel amount required for each of the intake pipe based fuel metering and the direct fuel metering, The internal combustion engine is provided with an exhaust gas recirculation means 560 in which the residual gas formed during combustion by this exhaust gas recirculation means is newly supplied to the internal combustion engine through the intake channel 535 of the intake pipe 505, In the method,
The metering fuel having the heat of the residual gas recirculated into the inlet channel 535 of the inlet pipe 505 is supplied and the inlet channel 535 of the inlet pipe 535, which is caused by the heat of the recirculated residual gas, Wherein the fuel distribution is moved (440) towards the proportionally higher intake-pipe-based fuel metering in response to the temperature rise of the fuel metered into the fuel tank. The method of claim 1, characterized in that the fuel metered through the suction pipe-based fuel metering is evaporated using heating of the inlet channel (535) of the suction pipe (505), which is enhanced due to the heat capacity of the recirculated residual gas , An internal combustion engine operating method. 3. The method of claim 1 or 2, wherein if the internal combustion engine is perceived as being in the cold start phase (405) or if the internal combustion engine is perceived as being in a transient mode from a low load to a higher load, (440) towards the higher fuel-metering-based fuel metering. 4. The method of claim 3, wherein if a cold start phase is recognized, a temperature is sensed at 405 and a maximum fuel quantity for the fuel tank metering based on the detected temperature is determined 420, The maximum amount of fuel that can be supplied for direct fuel metering is determined 425 and the determined amounts of fuel 420 and 425 and the total fuel amount 430 to be metered are compared 435 and based on the result of the comparison 435, The amount of excess fuel that is generated as the case may be converted by the corresponding amount increase (440) of the metered fuel through the intake pipe-based fuel metering. The fuel cell according to claim 3 or 4, wherein, referring to the fuel wall film model, how much fuel is deposited in the liquid state inside the wall of the suction pipe (505), how much fuel flows from the wall film in liquid form And the degree of fuel evaporation by the intake air and / or air / exhaust gas mixture resulting from the fuel wall film is determined by the temperature and the heat of the suction pipe 505 Is estimated according to the enthalpy and according to the temperature and the thermal enthalpy of the intake air and / or the air / exhaust gas mixture. 5. The method according to claim 3 or 4, wherein, referring to the piston temperature model and / or the combustion chamber wall temperature model, the heat stored in the piston of the internal combustion engine and / or in the combustion chamber wall, And is sufficient for combustion to occur. 7. A method according to any one of claims 4 to 6, characterized in that the quantity increase (440) is effected through a modification of the fuel distribution described above between the intake pipe-based fuel metering and the direct fuel metering. Way. 8. A method according to any one of claims 4 to 7, wherein the detected temperature (415) is from the following group:
The temperature of the intake channel of the internal combustion engine;
- ambient temperature;
- the temperature of the internal combustion engine;
- the oil temperature of the internal combustion engine;
The temperature of one or more pistons of the internal combustion engine, determined by reference to the model calculations; ≪ / RTI > 4. The method according to any one of claims 1 to 3, wherein if no cold starting step is detected, it can be checked whether there is a transient operating state of the internal combustion engine, and if a transient operating state is detected, Characterized in that the proportion of metered fuel through metering is relatively increased (440) with respect to metered fuel via direct fuel metering. 10. An internal combustion engine according to any one of claims 4 to 9, characterized in that an appropriate speed increase of the exhaust gas recirculation means (560) is additionally performed (445) in accordance with the result of the comparison (435) How it works. 11. A method according to any one of claims 1 to 10, characterized in that the fuel distribution is determined on the basis of the measured or calculated temperature of the at least one piston of the internal combustion engine. 12. The method according to claim 11, wherein when the transient operating mode is perceived or detected as an increase in the temperature of the at least one piston of the internal combustion engine, the amount of fuel metered by the direct fuel metering is continuously increased, Characterized in that the quantity of fuel to be metered is continuously reduced. 13. A computer program designed to perform each step of the method according to any one of claims 1 to 12. A computer program according to claim 13, wherein the computer program is stored. An electronic control device designed to control dual fuel metering using the method according to any one of claims 1 to 12.

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