WO2018108302A1

WO2018108302A1 - Method for operating an internal combustion engine designed to run on at least two fuels, correction control device, and internal combustion engine having such a correction control device

Info

Publication number: WO2018108302A1
Application number: PCT/EP2017/001310
Authority: WO
Inventors: Johannes Bauer; Tim SPÄDER; Roland Werner
Original assignee: Mtu Friedrichshafen Gmbh
Priority date: 2016-12-14
Filing date: 2017-11-10
Publication date: 2018-06-21
Also published as: DE102016225035A1; DE102016225035B4

Abstract

The invention relates to a method for operating an internal combustion engine (1) designed to run on at least two fuels. In a first operating state, a first actual amount (5) of a first fuel which is supplied to at least one combustion chamber of the internal combustion engine (1) is determined. A first target amount (7) for the first fuel is specified, and a correction value (9) is determined by comparison (8) of the first actual amount (5) of the first fuel with the first target amount (7) for the first fuel. A second actual amount (13) of a second fuel which is supplied to the at least one combustion chamber of the internal combustion engine (1) and is different from the first fuel is set on the basis of the correction value (9).

Description

DESCRIPTION Method for operating an internal combustion engine set up for operation with at least two fuels, correction control device and

Internal combustion engine with such a correction device

The invention relates to a method for operating an internal combustion engine adapted for operation with at least two fuels, a correction control device and an internal combustion engine having such a correction control device.

For operation with at least two fuels equipped internal combustion engines, in particular dual-fuel internal combustion engines, are typically operated with diesel, wherein the

Combustion air metered in a fuel gas and thus the diesel consumption can be reduced. It is necessary to maintain a certain relationship between diesel and fuel gas as accurately as possible. In particular, this is intended to prevent cost disadvantages arising from the fact that too little diesel is substituted by fuel gas, or emissions of the

Internal combustion engine increase due to an excessive amount of diesel, or a

Blend ignition deteriorated due to a too small amount of diesel. To set the specific relationship between diesel and fuel gas is an accurate knowledge of the

Characteristics of the fuel gas, in particular its calorific value, required, which, for example, when changing to other fuel gases whose properties are in particular not sufficiently known, requires complex analyzes. In practice, therefore, dual-fuel internal combustion engines are often operated without precise knowledge of the gas properties and consequently with improper, in particular irreproducible diesel fuel gas ratio, which typically leads to the above-mentioned problems.

The invention is based on the object, a method for operating a set up for operation with at least two fuels internal combustion engine, a

Correction control device and an internal combustion engine with such

To provide correction control device, said disadvantages do not occur. The object is achieved by providing the subject matters of the independent claims. Advantageous embodiments emerge from the subclaims.

The object is achieved in particular by providing a method for operating a combustion engine equipped for operation with at least two fuels, wherein in a first operating state a first actual quantity of a first fuel supplied to at least one combustion chamber of the internal combustion engine is determined, a first desired quantity for the fuel first fuel is given, and wherein by means of a comparison of the first actual amount of the first fuel with the first set amount for the first fuel, a correction value is determined. It is a second actual amount of a second at least one combustion chamber of the

Internal combustion engine supplied fuel, which is different from the first fuel, set in dependence on the correction value. The method has advantages over the prior art. Characterized in that the second actual amount of the second fuel in

Dependent on the correction value is set, a ratio of the first fuel to the second fuel in a reproducible manner adjustable, in particular independent of changed properties of the second fuel, such as its calorific value.

In particular, it is thereby possible to operate the internal combustion engine with the first and the second fuel, wherein the second fuel at least partially unknown

Properties, such as an unknown calorific value, may have. As a result, operating costs of the internal combustion engine can be reduced, since a potential for substitution of the first fuel by the second fuel can be optimally utilized. In addition, it can be avoided that too much amount of the first fuel is supplied to the combustion, whereby possibly emission limit values can not be met. In particular, it can also be avoided that too small an amount of the first fuel is supplied to the combustion, whereby a mixture ignition can deteriorate.

The internal combustion engine is preferably designed as a dual-fuel internal combustion engine. In the first operating state, the internal combustion engine is operated with the first and the second fuel.

The first actual amount of the first fuel is the combustion chamber in particular via a

Injection device supplied. The first actual amount of the first fuel is compared with the first target amount for the first

Fuel is preferably compared by forming a difference between the first actual amount and the first target amount. The correction value preferably gives a difference value for a mass or volume of the second fuel, or for a combustion air-fuel ratio, also referred to as

Lambda value is called, at.

An embodiment of the method is preferred which is characterized in that the first fuel used is a liquid fuel under normal conditions, that is to say at 25 ° C. and 1013 mbar, wherein a fuel which is gaseous under normal conditions is used as the second fuel. Preferably, the first fuel is an ignition oil, more preferably diesel or dimethyl ether. Preferably, the second fuel is a

Fuel gas. The term "fuel gas" is understood to mean flammable gases and gas mixtures., The fuel gas is preferably natural gas, biogas, landfill gas, sewage gas, mine gas, product gas from the wood gasification, lean gas, special gas or any mixture thereof.

An embodiment of the method is preferred, which is characterized in that the first actual amount of the first fuel by adjusting the second actual amount of the second

Fuel is regulated. In this case, in particular, a feedback mechanism is provided by which a change of the second actual quantity of the second fuel acts on the first actual quantity of the first fuel. This feedback mechanism is preferably designed such that the first actual quantity is reduced when the second actual quantity is increased, wherein the first actual quantity is increased when the second actual quantity is reduced. The regulation of the first actual quantity of the first fuel by setting the second actual quantity of the second fuel preferably takes place on a first, longer time scale.

In a preferred embodiment of the method, the second actual quantity of the second fuel is supplied to the at least one combustion chamber of the internal combustion engine

Combustion air, preferably upstream of an exhaust gas turbocharger of the internal combustion engine, mixed. It can thus be realized in particular a mixture charging. An embodiment of the method is preferred, which is characterized in that a rotational speed of the internal combustion engine by adjusting the first actual amount of the first

Fuel is regulated. The speed control is - as will be explained in more detail below - a feedback mechanism for the control of the first actual amount by adjusting the second actual amount of the second fuel. It is thereby almost a kind of superimposed controls on the one hand the speed and on the other hand, the first actual amount

carried out. Serving as an actuator for the speed control first actual amount is at the same time - mediated by the speed control - regulated by adjusting the second actual amount to the first target amount. The control of the speed of the internal combustion engine takes place on a second, shorter time scale, wherein the second, shorter time scale is shorter than the first, longer time scale, whereby the control of the speed of the internal combustion engine is performed faster than the control of the first actual amount of the first fuel , The first actual quantity of the first fuel is adjusted in particular such that the rotational speed of the internal combustion engine, which also depends on the second actual quantity of the second fuel, corresponds to a predetermined desired rotational speed of the internal combustion engine.

The regulation of the rotational speed of the internal combustion engine and the first actual quantity of the first fuel is explained by way of example below: In an initial state, for example, the first actual quantity of the first fuel is greater than the first setpoint quantity for the first fuel. This state can result, for example, from the fact that the calorific value of the second fuel decreases, which leads to a decrease in the rotational speed of the internal combustion engine, whereupon a rotational speed controller increases the first actual quantity of the first fuel beyond the first target quantity by the predetermined target rotational speed again to reach. By means of the comparison of the first actual quantity of the first fuel with the first set quantity for the first fuel, the correction value is determined. Depending on the correction value is in this

For example, set an increased second actual amount of the second fuel. Due to the increased second actual amount of the second fuel, the rotational speed of the internal combustion engine increases again, whereupon the rotational speed controller reduces the first actual quantity of the first fuel again in order to lower the rotational speed. This process is iteratively run until the first actual amount of the first fuel at a level of the first target amount for the first

Fuel is.

In a completely analogous manner, for example, an increase in the calorific value of the second leads

Fuel - at first unchanged second Istmenge - to increase the speed of the Internal combustion engine, which is in turn compensated by the speed controller by this lowers the first actual amount of the first fuel below the first target amount. The then determined correction value in turn means that the second actual amount of the second fuel is reduced, whereupon in turn decreases the speed of the internal combustion engine. The speed controller then responds by raising the first actual quantity of the first fuel in order to adjust the speed to the setpoint speed. This is in turn continued until the first actual quantity with the first target amount - at least within a predetermined tolerance limit - matches. Characterized in that the control of the speed of the internal combustion engine on the second time scale is performed faster than the control of the first actual amount of the first fuel on the first time scale, a total of a stable system is realized.

An embodiment of the method is preferred, which is characterized in that the first desired quantity for the first fuel in dependence on a desired torque of the internal combustion engine, and / or a rotational speed of the internal combustion engine, and / or certain environmental parameters of the internal combustion engine, and / or certain properties of the second fuel, and / or a knocking behavior of the internal combustion engine is specified. Preferably, a normal value for the first target amount for the first fuel by means of a map in dependence of the target torque and the speed of the

Internal combustion engine specified. The normal value for the first setpoint quantity is preferably determined on a test bench under normal conditions for the specific environmental parameters, in particular at an ambient temperature of 25 ° C. and / or an ambient air pressure of 1013 mbar. For deviations of the determined environmental parameters from the normal conditions, a correction value for the specification of the first setpoint quantity is preferably taken into account.

Preferably, at least one standard value for the particular properties of the second fuel, in particular its calorific value, and / or for the knocking behavior of the

Internal combustion engine specified, for deviations from the at least one

Default value in the operation of the internal combustion engine at least one further correction value in the specification of the first target amount for the first fuel is taken into account. It is possible that further correction values are formed, which in the specification of the first target amount be considered for the first fuel. It can therefore be made in an advantageous manner a parameterization of variables which determine the first set amount for the first fuel. An embodiment of the method is preferred, which is characterized in that a second setpoint quantity for the second fuel is predetermined, preferably as a function of the setpoint torque of the internal combustion engine, the second setpoint quantity being determined by the second setpoint quantity in conjunction with the correction value. The second setpoint quantity for the second fuel is preferably predefined by means of a characteristic map as a function of the setpoint torque. The second target amount for the second fuel is preferably set in the same unit as the correction value. However, it is decisive that the second actual quantity of the second fuel can be determined on the basis of the second setpoint quantity for the second fuel and the correction value. Preferably, a summation of the second set amount for the second fuel and the correction value, whereby the second actual amount of the second fuel is determined. The second setpoint is preferably given as the mass or volume of the second fuel, or as the combustion air-fuel ratio, and thus as the lambda value. If the correction value, as already explained, is given as the difference value for the mass or the volume of the second fuel or for the combustion air / fuel ratio, the second actual quantity can be determined in a simple manner by summing the second desired quantity and the correction value.

An embodiment of the method is preferred, which is characterized in that the internal combustion engine is operated in the first operating state with the first fuel and the second fuel when an operating point of the internal combustion engine, which in particular by the target torque of the internal combustion engine and the speed of the

Internal combustion engine is determined in a predetermined stationary

Dual-range map area is located. In particular, in the steady-state dual-fuel map area, the internal combustion engine is operated with the first and second fuels when a predetermined minimum speed and / or a predetermined operating temperature of the

Internal combustion engine is reached or exceeded. It is therefore possible, in particular, for the internal combustion engine to be operated in a second operating state only with the first fuel even in the stationary dual-fuel characteristic field range, if, for example after starting, the predetermined minimum rotational speed and / or the predetermined minimum torque

Operating temperature has not yet reached / are. It is especially possible that in addition or alternatively other conditions for a change from the second to the first

Operating state, and vice versa, are defined when preferably the operating point is in the stationary dual-fuel map area. The stationary dual-fuel characteristic field region is preferably located within a single-substance characteristic map of the internal combustion engine, which is spanned by at least two axles on which the-in particular instantaneous-rotational speed of the internal combustion engine and the nominal torque of the internal combustion engine are removed. If the operating point lies in the single-substance map, in particular outside the stationary binary map area, then

the internal combustion engine is preferably operated only with the first fuel. The

Internal combustion engine is then in the second operating state.

An embodiment of the method is preferred, which is characterized in that the operating point in an operation of the internal combustion engine with the first and the second fuel for a predetermined time outside the predetermined stationary

Dual-range map area may lie. Preferably, the predetermined period of time is freely parameterizable. If the predetermined time period is exceeded and the specific operating point is still outside the stationary dual-fuel map area, the

Internal combustion engine preferably from the first operating state to the second

Operating state offset. So it is especially in a transient operation of

Internal combustion engine possible to prevent that at operating points - especially at the edge of the stationary dual-fuel map area - constantly between the first and the second operating state is changed back and forth. The object is also achieved, in particular, by providing a correction control device for regulating a fuel metering for an internal combustion engine set up for operation with at least two fuels. The correction control device is set up to use a comparison of a first actual quantity of a first, at least one combustion chamber of the

Internal combustion engine supplied fuel with a first target amount for the first

Fuel to determine a correction value, wherein the correction control means is arranged to a second actual amount of a second the at least one combustion chamber of the

Internal combustion engine supplied fuel, which is different from the first fuel, to adjust in dependence on the correction value. In particular, the

Correction control device adapted to carry out a method according to one of the above described embodiments. In connection with the correction control device, in particular, the advantages that have already been explained in connection with the method result. The object is also achieved in particular by providing an internal combustion engine which is set up for operation with at least two fuels, wherein the

Internal combustion engine having a correction control device according to one of the embodiments described above. In connection with the internal combustion engine, the advantages which have already been explained in connection with the method result in particular.

The description of the method on the one hand and the correction control device and / or the internal combustion engine on the other hand are to be understood as complementary to one another. In particular, method steps that are explicit or implicit in connection with the

Correction control device and / or the internal combustion engine have been described, preferably individually or combined with each other steps of a preferred embodiment of

Process. Features of the correction control device and / or the internal combustion engine, which have been explained explicitly or implicitly in connection with the method, are preferably individually or combined with one another Features of a preferred embodiment of the correction control device and / or the internal combustion engine. The method is preferably characterized by at least one method step, which is caused by at least one feature of a preferred embodiment according to the invention or of the correction control device and / or the internal combustion engine. The correction control device and / or the internal combustion engine preferably draw / are characterized by at least one feature which is characterized by at least one step of a preferred embodiment of the invention

Embodiment of the method is conditional.

The invention will be explained in more detail below with reference to the drawing. 1 shows a schematic representation of an embodiment of a

Internal combustion engine with a correction control device;

Figure 2 is a schematic representation of an embodiment of a

Correction control system; Figure 3 is a schematic representation of certain states of

Internal combustion engine, and

Figure 4 is a schematic representation of a map of the internal combustion engine.

Fig. 1 shows schematically an embodiment of an internal combustion engine 1, which is adapted for operation with at least two fuels. The internal combustion engine 1 has a correction control device 3. Within the scope of an embodiment of the method for operating the internal combustion engine 1, a first actual quantity 5 of a first fuel supplied to at least one combustion chamber of the internal combustion engine 1 is determined in a first operating state. It is given a first target amount 7 for the first fuel. By means of a comparison 8 of the first actual quantity 5 of the first fuel with the first desired quantity 7 for the first fuel and further steps (not shown here), which are described in more detail in FIG. 2, a correction value 9 is determined. A second actual quantity 13 of a second fuel supplied to the at least one combustion chamber of the internal combustion engine 1 is set as a function of the correction value 9. The first fuel and the second fuel are different from each other.

In the first operating state, the internal combustion engine is preferably operated with the first and the second fuel. In a second operating state, the

Internal combustion engine 1 preferably operated only with the first fuel. Preferably, a liquid fuel is used as the first fuel, with a gaseous fuel, in particular a fuel gas, being used as the second fuel.

The first actual quantity 5 of the first fuel is preferably regulated by setting the second actual quantity 13 of the second fuel. Preferably, an admixing 15 of the second actual quantity 13 of the second fuel to combustion air, which is the at least one combustion chamber of the internal combustion engine 1 is supplied.

By means of a speed controller 17, a speed of the internal combustion engine 1 is regulated by adjusting the first actual quantity 5 of the first fuel. The speed of the internal combustion engine 1 is in particular dependent on the first actual quantity 5 of the first fuel and of the second actual amount 13 of the second fuel, in particular also depending on their calorific value, wherein the speed controller 17, the first actual amount 5 of the first fuel so pretends that a predetermined speed of the internal combustion engine 1 is achieved. The control of the rotational speed of the internal combustion engine 1 is preferably carried out faster than the control of the first actual amount 5 of the first fuel.

The speed controller 17 is preferably associated with a limiting member 19, which specifies a limit value for the first actual quantity 5 of the first fuel, so that in particular a maximum torque and / or a maximum rotational speed of the internal combustion engine 1 is not exceeded. Preferably, the first actual quantity 5 of the first fuel is adjusted by means of the speed controller 17 and the limiting member 19, wherein this is metered by an injection device 21 to the at least one combustion chamber.

The first setpoint quantity 7 for the first fuel is predetermined by a first setpoint setpoint 25, which is explained in more detail in FIG.

A second setpoint quantity 26 for the second fuel is produced, in particular, by a second setpoint quantity input 27, preferably as a function of a setpoint torque

Internal combustion engine 1 predetermined. The second actual quantity 13 is preferably determined by the second setpoint quantity 26 for the second fuel in combination with the correction value 9. The correction value 9 is offset with the second setpoint quantity 26, preferably by means of a first summation element 28, whereby the second actual quantity 13 is predetermined.

The correction control device 3 is thus set up to determine the correction value 9 by means of a comparison 8 of the first actual quantity 5 of the first fuel with the first set quantity 7 for the first fuel, wherein the correction control device 3 is set up to generate the second actual quantity 13 of the second fuel Depend on the correction value 9. Fig. 2 shows a schematic representation of the correction control device 3. The same and functionally identical elements are provided with the same reference numerals, so that reference is made to the preceding description. Preferably, the first set amount 7 for the first fuel in dependence on the target torque of the internal combustion engine 1, and / or a rotational speed of the internal combustion engine 1, and / or certain environmental parameters of Internal combustion engine 1, and / or certain properties of the second fuel, and / or a knocking behavior of the internal combustion engine 1 predetermined. Figure 2 shows the first

Target quantity specification 25 for specifying the first target quantity 7 for the first fuel.

Preferably, a normal value 29 for the first setpoint quantity 7 for the first fuel is predefined by means of a characteristic map as a function of the setpoint torque and / or the speed of the internal combustion engine 1. The normal value 29 for the first target quantity 7 is preferably determined on a test bench under normal conditions

Ambient parameters, in particular at an ambient temperature of 25 ° C and / or an ambient air pressure of 1013 mbar determined. A departure from the

Normal conditions are preferably taken into account with a first correction value 31 in the specification of the first set quantity 7 for the first fuel.

Preferably, at least one default value for the specific properties of the second fuel, in particular its calorific value, is specified, wherein a deviation from the at least one default value with a second correction value 33 is taken into account when specifying the first target quantity 7.

Furthermore, preferably at least one default value for the knocking behavior of

Internal combustion engine 1 predetermined, with a deviation from the at least one

Standard value with a third correction value 35 in the specification of the first target amount 7 is taken into account. It is possible that further correction values 37 are formed, which are taken into account when prescribing the first set quantity 7 for the first fuel.

The first setpoint quantity 7 of the first fuel is preferably given as a function of the normal value 29 for the first setpoint quantity 7 for the first fuel and the at least one correction value 31, 33, 35, 37, wherein the combination of the normal value 29 and the correction values 31, 33, 35, 37 preferably by means of a Zusammenfuhrungsglieds 39, which is preferably designed as a second summation member is performed. By means of a difference element 41, the comparison 8 of the first setpoint quantity 7 for the first fuel with the first actual quantity 5 of the first fuel takes place. A comparison value 43 formed by the comparison 8, which is preferably a difference between the first

Set amount 7 and the first actual amount 5 represents is fed to a filter 45. The filter 45 checks the comparison value 43 in particular for a maximum deviation of the first Target quantity 7 of the first actual quantity 5. Preferably, the filter 45 limits the comparison value 43 to a predetermined limit comparison value. The output variable of the filter 45 is, in particular, a filtered comparison value 47. The filtered comparison value 47 is supplied to a control element 49, which is preferably designed as a proportional-integral-derivative controller (PID controller). From the filtered comparison value 47 are by means of a

Determination member 51 filter parameter 53 derived for the control element 49. The filter parameters 53 comprise, in particular, a proportional component Kp and / or a readjustment time Tn for the control element 49. Finally, the control element 49 generates the correction value 9. FIG. 3 shows a schematic representation of certain states of the internal combustion engine 1. The same and functionally identical elements are the same Reference numerals provided so that reference is made to the preceding description.

In particular, the internal combustion engine 1 is operated only with the first fuel in a first state "single-fuel operation" 55. In this first state 55, the brera engine 1 is in particular from a second state "engine off" 57 can be displaced by means of a first command "engine start" 58. Furthermore, the internal combustion engine 1 can be displaced from the first state "single-fuel operation" 55 into the second state "engine off" 57 by means of a second command "engine stop" 58 'if the internal combustion engine 1 in particular is switched off via a shutdown command 59.

In particular, the first state "single-substance operation" 55 is set even if a third command 61 is issued, for example, by an operator or by a dual-substance diagnostic system, in particular if an error is detected

"Single-substance operation" 55 can preferably be implemented starting from each of the states described below, in particular triggered by means of the dual-substance diagnosis system The first state "single-substance operation" 55 remains set as long as, in particular, no two-substance release 63 takes place on the part of the dual-substance diagnosis system. Is this done?

Zweistofffreigabe 63, the internal combustion engine 1 is placed in a third state "two-substance Init" 65.

From the third state "Zweistoff Init" 65, the internal combustion engine 1 is placed in a fourth state "binary ready" 67. In the fourth state "binary ready" 67 is the Internal combustion engine 1 operated only with the first fuel. In particular, given a fourth command "binary start" 69 due to the location of an operating point of the internal combustion engine 1, the internal combustion engine 1 is set to a fifth state "activate second fuel" 71. Specifically, if the two-component diagnosis system gives a release 73 of the second fuel, the internal combustion engine 1 is set to a sixth state "dual-substance start" 75. In this sixth state 75, operation of the internal combustion engine 1 with the first and the second fuel is changed Start of injection (Begin Of Injection - BOI) and / or a rail pressure PRAIL is adapted for the internal combustion engine 1. After this change of the maps, a seventh state "binary active" 77 is taken, in which the internal combustion engine 1 operated with the first and the second fuel becomes.

If, due to the position of an operating point of the internal combustion engine 1, a fifth command "terminate binary" 78 is given, preferably an eighth state "binary stop" 79 is assumed. It is also possible for this eighth state to be assumed if this is specified by an operator or the two-component diagnostic system, for example when an error is detected. It will in particular return to an operation of

Internal combustion engine 1 changed only with the first fuel. Subsequently, the internal combustion engine 1 is set to a ninth state "deactivate second fuel" 81. The internal combustion engine 1 is then again operated in particular only with the first fuel and is put into the fourth state "binary ready" 67. Preferably, the internal combustion engine 1 is then placed in the third state "binary init" 65 via a sixth command "dual-function reset" 83. But it is also possible that the

Internal combustion engine 1 of the fourth state "binary ready" 67 is set directly in the first state "single-material operation" 55, which is not shown in Figure 3.

Fig. 4 shows a schematic representation of a map of the internal combustion engine 1. The same and functionally identical elements are provided with the same reference numerals, so that reference is made to the preceding description.

The map has a rotational speed axis 85, on which a particular instantaneous speed of the internal combustion engine 1 is removed. On a setpoint torque axis 87, a setpoint torque of the internal combustion engine 1 is removed. A single-substance map 89 is provided. Is in particular by the target torque and the speed of Internal combustion engine 1 certain operating point of the internal combustion engine 1 in the single-fuel map 89, the internal combustion engine 1 is operated in particular only with the first fuel, wherein the internal combustion engine 1, in particular in the second operating state, for example in the first state "single-material operation" 55, is located.

Furthermore, a predetermined stationary two-substance map area 91 is provided. If the specific operating point is therein, the internal combustion engine 1 can be operated with the first and the second fuel, the internal combustion engine 1 then being in particular in the first operating state, for example in the seventh state "dual-active" 77. In particular, the internal combustion engine 1 in the stationary dual-fuel map area 91 with the first and the second fuel operated, if a predetermined

Minimum speed and / or a predetermined operating temperature of the internal combustion engine 1 is reached or exceeded / are. So it is possible in particular that the

Internal combustion engine 1 is operated in the stationary dual-fuel map area 91 only with the first fuel when, for example, after the start, the predetermined

Minimum speed and / or the predetermined operating temperature is not yet reached, or other conditions for operation with the first and the second fuel are not yet met. The stationary binary map area 91 is preferably as a three-dimensional

Map area formed. There is provided an upper portion 9 "and a lower portion 91", as viewed by a viewer, and the upper and lower portions 91 ', 91 "are here separated by a dashed line. If the internal combustion engine 1 is operated in particular at a higher ambient air pressure, the stationary two-component map area 91 preferably comprises the upper and the lower region 9, 91 ". If the internal combustion engine is operated at a lower ambient air pressure, in particular at a greater geodetic level, the stationary dual-fuel map region 91 comprises preferably only the lower region 91 ". Such an adaptation of the stationary dual-fuel characteristic area 91 can, in particular, overheat the internal combustion engine 1 during operation

be avoided in particular by a lower ambient air pressure that a

Upper limit of the target torque is reduced. In the following, it is assumed that a stationary two-substance map area 91 consisting of the upper and the lower area 91 ', 9 Γ'. Furthermore, a transient binary characteristic map area 93 is provided, which is preferably designed as a three-dimensional map area. During operation of the internal combustion engine 1 with the first and the second fuel, the specific operating point may lie outside the predetermined stationary binary characteristic map region 91, in particular in the transient binary characteristic map region 93, for a predetermined period of time. The certain one

Operating point of the internal combustion engine 1 can therefore lie in the transient dual-fuel characteristic area 93 for the predetermined, in particular maximum time period, in particular without the internal combustion engine 1 from the first operating state, for example the seventh state "binary active" 77, into operation only with the first fuel. Thus, the second operating state, for example, the first state "single-material operation" 55 or the third state "binary substance Init" 65. If the predetermined time has expired and the specific operating point is still in the transient binary map area 93, is preferably a change of In the case of a shift of the specific operating point from the single-substance characteristic field 89 directly, ie not via the stationary dual-substance characteristic field region 91, into the transient one

Dual-fuel characteristic area 93, there is preferably no change from the second operating state to the first operating state. Is the specific operating point in the stationary or in the transient

Dual-fuel characteristic area 91, 93, so there is, under certain conditions, a possibility for operation of the internal combustion engine 1 in the first operating state. However, it is also possible in particular for the internal combustion engine 1 to be operated in the second operating state at a position of the specific operating point in the stationary or transient binary characteristic map region 91, 93.

Overall, it turns out that by the method, the correction rule 3 and the

Internal combustion engine 1, a safe operation of the internal combustion engine 1 with the first fuel, in particular diesel, and the second fuel, in particular a fuel gas at

different, in particular unknown properties of the second fuel, for example, its calorific value is possible, with an optimal substitution of the first fuel by the second fuel and thus cost savings can be realized.

Claims

A method of operating one for operation with at least two fuels

equipped internal combustion engine (1), wherein in a first operating state

a first actual quantity (5) of a first, at least one combustion chamber of

Internal combustion engine (1) supplied fuel is determined, wherein

a first setpoint quantity (7) for the first fuel is specified, wherein - a correction value (9) is determined by means of a comparison (8) of the first actual quantity (5) of the first fuel with the first setpoint quantity (7) for the first fuel, and in which

a second actual quantity (13) of a second fuel supplied to the at least one combustion chamber of the internal combustion engine (1), which is different from the first fuel, is adjusted as a function of the correction value (9).

2. The method according to claim 1, characterized in that a liquid fuel is used as the first fuel, wherein as the second fuel, a gaseous fuel is used.

3. The method according to any one of the preceding claims, characterized in that the first actual amount (5) of the first fuel by adjusting the second actual amount (13) of the second fuel is controlled.

4. The method according to any one of the preceding claims, characterized in that a speed of the internal combustion engine (1) by adjusting the first actual amount (5) of the first fuel is controlled, wherein preferably the control of the speed of

Internal combustion engine (1) is performed faster than the control of the first actual amount (5) of the first fuel.

5. The method according to any one of the preceding claims, characterized in that the first set amount (7) for the first fuel as a function of

a) a target torque of the internal combustion engine (1), and / or

b) a speed of the internal combustion engine (1), and / or c) certain environmental parameters of the internal combustion engine (1), and / or d) certain properties of the second fuel, and / or

e) a knocking behavior of the internal combustion engine (1)

is given.

6. The method according to any one of the preceding claims, characterized in that a second set amount (26) for the second fuel is preferably given in dependence on the target torque of the internal combustion engine (1), wherein by the second

Target quantity (26) in conjunction with the correction value (9) the second actual quantity (13) is determined.

7. The method according to any one of the preceding claims, characterized in that the internal combustion engine (1) is operated with the first fuel and with the second fuel when an operating point of the internal combustion engine (1) in a predetermined stationary two-fuel map area (91).

8. The method according to any one of the preceding claims, characterized in that during operation of the internal combustion engine (1) with the first and the second fuel, the operating point for a predetermined period of time may be outside the predetermined stationary dual map area (91).

9. correction control device (3) for controlling a fuel metering for a set up for operation with at least two fuels internal combustion engine (1), characterized

marked that

- The correction control device (3) is adapted to by means of a comparison (8) of a first actual amount (5) of a first, at least one combustion chamber of the internal combustion engine (1) supplied fuel with a first set amount (7) for the first fuel, a correction value (9 ), where

the correction control device (3) is set up to supply a second actual quantity (13) of a second to the at least one combustion chamber of the internal combustion engine (1)

Adjusting fuel, which is different from the first fuel, in dependence on the correction value (9), and wherein

- The correction control device (3) is in particular adapted for carrying out a method according to one of claims 1 to 8.

10. internal combustion engine (1), designed for operation with at least two fuels, characterized in that the internal combustion engine (1) has a correction control device (3) according to claim 9.