DE102017128853A1 - Exhaust after-treatment system for an internal combustion engine and method for operating an internal combustion engine - Google Patents

Abstract

The invention relates to an internal combustion engine (10) with an exhaust aftertreatment system (20). The exhaust aftertreatment system (20) comprises an open particle filter (22), which is followed by an exhaust aftertreatment component for reducing nitrogen oxide emissions (24, 38). The internal combustion engine (10) is designed as a self-igniting internal combustion engine (10) according to the diesel principle and is operated with a special fuel (52) which contains at least 5% of a C1 fuel, in particular an oxymethylene ether (OME).
Furthermore, a method for operating such an internal combustion engine (10) is proposed, wherein upon detection of incorrect refueling with conventional, fossil diesel fuel suitable measures, in particular a limitation of the engine power, the torque and / or the dynamic operation are initiated to reduce the raw emissions of particles and to comply with the valid exhaust emissions despite the misfueling.

Description

The invention relates to an exhaust aftertreatment system for an internal combustion engine and to a method for operating an internal combustion engine with a special fuel.

The current and increasingly stringent future exhaust gas legislation places high demands on the engine raw emissions and the exhaust aftertreatment of internal combustion engines. The demands for a further reduction in consumption and the further tightening of emission standards with regard to permissible nitrogen oxide emissions pose a challenge to engine developers. In gasoline engines, exhaust gas purification takes place in a known manner via a three-way catalytic converter, as well as the three-way catalytic converter. Catalyst upstream and downstream further catalysts. Exhaust aftertreatment systems are currently used in diesel engines which have an oxidation catalytic converter or a NOx storage catalytic converter, a catalyst for the selective catalytic reduction of nitrogen oxides (SCR catalytic converter) and a particle filter for separating soot particles and optionally further catalysts. According to the current state of the art, such a particulate filter is necessary for achieving the particulate limit values of the EU5 emission standard or more stringently. In this case, closed particle filters are used, which must be regenerated periodically, which is done by a thermal regeneration, that is by a Rußabbrand the particles retained in the particle filter. Furthermore, coated particle filters are known which have a coating for the selective, catalytic reduction of nitrogen oxides and thus include the function of an SCR catalyst. The reducing agent used is preferably ammonia. Because the handling of pure ammonia is complicated, in vehicles usually a synthetic, aqueous urea solution is used, which is mixed in a SCR catalyst upstream mixing device with the hot exhaust gas stream. By this mixing, the aqueous urea solution is heated, wherein the aqueous urea solution releases ammonia in the exhaust gas passage. A commercial, aqueous urea solution is generally composed of 32.5% urea and 67.5% water.

From the DE 10 2010 005 813 A1 For example, a diesel engine is known in which a particle filter is arranged in the exhaust gas passage downstream of two turbochargers and an SCR catalytic converter downstream of the particle filter. Downstream of the turbine of the first turbocharger and upstream of the turbine of the second turbocharger and / or downstream of the second turbine and upstream of the particulate filter is at least one element for reducing emissions of unburned hydrocarbons or nitrogen oxides known in which unburned hydrocarbon and / or the nitrogen oxides are stored In which the elements for reducing emissions can be periodically regenerated.

From the DE 10 2015 120 106 A1 For example, a method and apparatus for adjusting the ignition characteristics of a fuel are known. In this case, at least part of the fuel is oxidized with an oxidizing agent to a catalyst on a catalyst support. In a conversion zone of the device, at least a portion of the distributed fuel and / or other supplied fuel is thermally and / or catalytically converted. The method is characterized in that the ignition of the fuel is adjusted by the molar ratio of oxygen contained in the oxidizing agent to the oxygen required for complete oxidation of the fuel present, and / or the pressure in the unit and / or the residence time and / or the temperature ,

The EP 2 853 707 B1 discloses a diesel engine, in whose exhaust system in the flow direction of an exhaust gas through the exhaust system a close-coupled diesel particulate filter, downstream of the diesel particulate filter is arranged a turbine of an exhaust gas turbocharger and downstream of the turbine, a catalyst for the selective catalytic reduction of nitrogen oxides. It is provided that for heating the particulate filter for regeneration, a late post-injection of fuel into the combustion chambers of the engine or in the exhaust duct upstream of the oxidation catalyst takes place and the unburned fuel for heating the exhaust aftertreatment components, in particular for heating the particulate filter is exothermically reacted in the exhaust duct.

A disadvantage of the known solutions, however, is that closed particulate filter significantly increase the exhaust back pressure and the exhaust back pressure increases further by the load. Therefore, closed particle filters must be regenerated at regular intervals, usually at a particle loading of about 4 g of particle mass per dm ³ filter volume thermally by burning of the particles. This leads to a corresponding additional consumption of the internal combustion engine and can lead to increased pollutant emissions during the regeneration of the particulate filter.

Furthermore, from the prior art open particle filters, which are also referred to as particle reduction systems or particulate reduction catalysts, but which are not able to ensure a reduction of particulate emissions in diesel engines due to their comparatively low particle storage capacity, which would be sufficient to meet the EU5 emission standard or a stricter emission standard.

The object of the invention is to keep the exhaust gas back pressure as low as possible and to comply with the current and future emission limit values with a simple and inexpensive exhaust aftertreatment system and to reduce the raw emissions (for example oxygenates) specific to the use of C1 fuels.

According to the invention, this object is achieved by an internal combustion engine having a fuel system and an exhaust aftertreatment system, the exhaust aftertreatment system having a particle reduction unit and an exhaust aftertreatment component downstream of the particle reduction unit for reducing nitrogen oxide emissions. The particle reduction unit is designed as an open particle filter and the internal combustion engine as a self-igniting internal combustion engine according to the diesel principle. The internal combustion engine is operated with a special fuel, which has at least 5% of a C1 fuel. C1 fuels are fuels in which there are no chemical bonds between two carbon atoms. Such C1 fuels burn virtually free of soot. Even with a mixture of a C1 fuel with another fuel reductions in soot emissions are disproportionate to the mixing ratio of the soot emissions possible. Through an open particle filter, the exhaust backpressure can be lowered compared to a closed diesel particulate filter, resulting in a reduction in consumption. In addition, no periodic regeneration of the particulate filter is necessary so that regeneration phases with increased consumption and increased emissions are avoided.

An open particulate filter, which is also referred to as a particulate catalyst, is a continuously catalytically regenerating particulate reduction system. In particle catalysts, the particles stored there are oxidized at sufficiently high temperatures and NO ₂ concentrations, and so the open particle filter is continuously regenerated according to the so-called CRT (Continuous Regenerating Trap) principle. The nitrogen dioxide is formed from nitrogen oxide in the upstream oxidation catalyst and optionally at catalytically coated surfaces in the open particle filter. The structure of the open particle filter ensures that particles are briefly held on the filter surface and reacted with the continuously flowing nitrogen dioxide. The storage capacity of an open particle filter is small compared to known closed particle filters. While the storage capacity of a closed particulate filter is greater than 5 grams per liter of filter volume, the storage capacity of an open particulate filter is significantly less than 1 gram per liter of filter volume. Therefore, in the operation of the open particulate filter only a very small increase of the exhaust gas back pressure occurs due to a loading of the filter. Unlike closed-loop particulate filters, there is no need to specifically increase the exhaust gas temperature for regeneration of the particulate filter.

Due to the features mentioned in the dependent claims, advantageous improvements and further developments of the internal combustion engine mentioned in the independent claim are possible.

In a preferred embodiment of the invention it is provided that the C1 fuel is an oxymethylene ether (OME). An oxymethylene ether is a particularly simple and cost-producible representative of the C1 fuels, with which the described positive effects on the reduction of the particle raw emissions during the combustion of the fuel in the combustion chambers of the internal combustion engine can be achieved.

In an advantageous embodiment of the invention it is provided that the open particle filter has an electrical heating element. By an electric heating element, the catalytic effect of the open particulate filter can be improved, in particular can be achieved in a upstream oxygenate storage catalyst or a coating for intermediate storage of oxygenates, a catalytic activation of the particulate filter before it comes to a thermal desorption of the oxygenates.

In a further improvement of the exhaust aftertreatment system, it is provided that the exhaust aftertreatment component for reducing the nitrogen oxide emissions is a NOx storage catalytic converter or an SCR catalytic converter. An NOx storage catalyst is an effective and cost effective catalyst for reducing nitrogen oxide emissions. In this case, one or more NOx storage catalytic converters can be provided in the exhaust system. An SCR catalytic converter is more expensive than a NOx storage catalytic converter, but in its catalytically effective temperature range offers even better possibilities for reducing nitrogen oxide emissions. Furthermore, it is possible for the SCR catalytic converter to be followed by a NOx storage catalytic converter.

It is particularly preferred if the component for reducing the nitrogen oxide emissions is an SCR catalytic converter and downstream of the open particle filter and upstream of the SCR catalytic converter a metering module is provided for metering a reducing agent into the exhaust gas system. The SCR catalyst needs to be selective, catalytic reduction of nitrogen oxides is a suitable reducing agent. Preferably, aqueous urea solution is metered into the exhaust passage of the internal combustion engine for the reduction of nitrogen oxides. In this case, metering downstream of the open particle filter is expedient, so that the ammonia obtained from the aqueous urea solution is not converted into nitrogen oxides by a coating of the particle filter and thus leads to an emission deterioration.

In a preferred embodiment of the internal combustion engine, it is provided that the open particle filter is arranged in the flow direction of an exhaust gas of the internal combustion engine through an exhaust system of the internal combustion engine as a first emission-reducing exhaust aftertreatment component. Thereby, the particles can be effectively removed from the exhaust gas before the exhaust gas flows into further exhaust aftertreatment components. This reduces the risk of damaging these further exhaust aftertreatment components by soot particles in the exhaust gas.

In a further improvement of the invention, it is provided that an oxygenate storage catalytic converter is arranged in the exhaust system of the internal combustion engine or the open particle filter is provided with a coating for storing oxygenates. C1 fuels have the disadvantage that combustion can lead to an increase in aldehyde emissions. To effectively reduce these aldehyde emissions, an oxigenate storage catalyst is advantageous which can retain the aldehyde emissions until a catalytic coating of the open particulate filter has achieved its effectiveness.

It is preferred if the oxigenate storage catalytic converter comprises a zeolite reservoir and is arranged downstream of the turbine of the exhaust gas turbocharger and upstream of the open particulate filter in the exhaust system.

According to the invention, a method is proposed for operating an internal combustion engine with a fuel system and an exhaust aftertreatment system, in which a particle reduction unit and an exhaust aftertreatment component downstream of the particle reduction unit are provided for reducing nitrogen oxide emissions, wherein the internal combustion engine is designed as a self-igniting internal combustion engine according to the diesel principle and is operated with a special fuel , and wherein the particulate reduction unit is designed as an open particulate filter, wherein the particulate matter emissions of the internal combustion engine are lowered by mixing the special fuel at least 5% of a C1 fuel. By a method according to the invention for operating an internal combustion engine, the specifications of the current exhaust gas legislation can be achieved without additional, expensive exhaust aftertreatment components and the consumption of the internal combustion engine can be reduced.

In an advantageous improvement of the method it is provided that a fuel sensor for detecting the fuel quality is provided on the fuel supply system, in particular on the fuel tank or a fuel line which connects the fuel tank with the injectors. Alternatively, a recognition of the fuel quality from the engine data by a control unit of the internal combustion engine is provided with advantage, in particular based on the injection quantity, the cylinder pressure curve, pressures and temperatures in the exhaust system or similar parameters, which can be distinguished between a conventional fossil diesel fuel and the proposed special fuel wherein, upon detection of misfuelling with conventional fossil diesel fuel, the engine parameters of the internal combustion engine are adjusted to lower particulate emissions below the threshold of the emission standard to be met.

The various embodiments of the invention mentioned in this application are, unless otherwise stated in the individual case, advantageously combinable with each other.

• 1 ein erstes Ausführungsbeispiel eines Verbrennungsmotors mit einem erfindungsgemäßen Abgasnachbehandlungssystem;
• 2 ein zweites Ausführungsbeispiel eines Verbrennungsmotors mit einem erfindungsgemäßen Abgasnachbehandlungssystem;
• 3 ein drittes Ausführungsbeispiel eines Verbrennungsmotors mit einem erfindungsgemäßen Abgasnachbehandlungssystem;
• 4 ein weiteres Ausführungsbeispiel eines Verbrennungsmotors mit einem erfindungsgemäßen Abgasnachbehandlungssystem;
• 5 ein weiteres Ausführungsbeispiel eines Verbrennungsmotors mit einem erfindungsgemäßen Abgasnachbehandlungssystem; und
• 6 ein Ablaufdiagramm zur Durchführung eines erfindungsgemäßen Verfahrens zum Betreiben eines Verbrennungsmotors.

The invention will be explained below in embodiments with reference to the accompanying drawings. The same components or components with the same function in the drawings are each identified by the same reference numerals. Show it:

• 1 a first embodiment of an internal combustion engine with an exhaust aftertreatment system according to the invention;
• 2 A second embodiment of an internal combustion engine with an exhaust aftertreatment system according to the invention;
• 3 A third embodiment of an internal combustion engine with an exhaust aftertreatment system according to the invention;
• 4 a further embodiment of an internal combustion engine with an exhaust aftertreatment system according to the invention;
• 5 a further embodiment of an internal combustion engine with an exhaust aftertreatment system according to the invention; and
• 6 a flowchart for performing a method according to the invention for operating an internal combustion engine.

1 shows an internal combustion engine 10 for a motor vehicle, which is designed as a self-igniting internal combustion engine according to the diesel principle. The internal combustion engine 10 has four combustion chambers 12 but, alternatively, with more or less combustion chambers 12 be designed in particular as a three-cylinder, five-cylinder, six-cylinder or eight-cylinder engine. The internal combustion engine 10 has an outlet 14 on, which with an exhaust system according to the invention 16 of the internal combustion engine 10 connected is. In the exhaust system 16 is downstream of the outlet 14 a turbine 26 an exhaust gas turbocharger 18 arranged. Downstream of the turbine 26 is the first emission-reducing exhaust gas component an open particle filter 22 and downstream of the open particulate filter 22 an SCR catalyst 24 arranged. The introduction of reducing agent is downstream of the open particulate filter 22 and upstream of the SCR catalyst 24 a dosing module 28 for dosing the reducing agent 26 , in particular of aqueous urea solution provided. Downstream of the SCR catalyst 24 is a particle sensor 30 provided, which via a signal line 32 with a control unit 34 of the internal combustion engine 10 connected is. Furthermore, at the exhaust system 16 further sensors, in particular a sensor for detecting the concentration of nitrogen oxide or a temperature sensor, be arranged, which also via a signal line 32 with the control unit 34 are connected.

The internal combustion engine 10 further includes a fuel supply system 40 on which a fuel injection system 40 with a special fuel 52 is supplied and about which in a fuel tank 58 stored special fuel 52 in the combustion chambers 12 of the internal combustion engine 10 can be metered. The fuel injection system 40 includes a first fuel line 42 which the fuel tank 8th with a high-pressure fuel pump 44 combines. The high-pressure fuel pump 44 is over another fuel line 54 with a high-pressure accumulator 46 connected, from which injectors 48 for injection of fuel into the combustion chambers 12 of the internal combustion engine 10 with the in the high-pressure accumulator 46 stocked special fuel 52 be fed. Further, on the fuel tank 58 a fuel sensor 54 be arranged for determining the fuel quality, in particular for determining the fuel composition, which via a further signal line 32 with the control unit 34 of the internal combustion engine 10 connected is. The exhaust aftertreatment system 20 is free from a closed particulate filter because it does not require a significant particle mass reduction. The open particle filter 22 has a volume of 0.3 - 2.0 dm ³ per liter displacement of the internal combustion engine 10 , preferably from 0.5 to 1.5 dm ³ , more preferably from 0.7 to 0.8 dm ³ and has a noble metal content of less than 125 g / ft ³ , preferably less than 100 g / ft ³ , more preferably of less than 75 f / ft ³ , in particular less than 50 g / ft ^3, in a platinum-palladium mixture having a palladium content of not more than 25%, preferably less than 15%, in particular less than 5%.

The SCR systems can with knowledge of the fuel composition of the special fuel 52 the metering feedforward control or dosing control to the corresponding special fuel 52 to adjust. A fuel detection can from the engine data of the internal combustion engine 10 through the control unit 34 , In particular via an evaluation of the injection quantity, the cylinder pressure curve in the combustion chambers 12 , Pressures and temperatures in the exhaust system 16 , A speed curve over the crank angle, done. Alternatively, a fuel detection via at least one fuel sensor 56 in the fuel tank 58 or in the fuel lines 42 . 54 to the internal combustion engine 10 or be derived by telemetry, in particular by a communication of the fuel pump with the vehicle when refueling the motor vehicle.

A variant of the internal combustion engine 10 solves when refueling with a fuel, which of the proposed special fuel 52 deviates from appropriate measures. The detection of such misfuelling can preferably by a fuel sensor 56 , but also by the evaluation of suitable engine data of the internal combustion engine 10 through the control unit 34 respectively. Suitable measures include a warning signal, which is preferably transmitted optically to the driver and / or an adjustment of the engine operation to avoid damage to the internal combustion engine 10 , the exhaust aftertreatment system 20 or the vehicle. In this case, in particular, a restriction of the rotational speed and / or the torque of the internal combustion engine 10 intended. Furthermore, an adaptation of the engine operation is provided, such that also with the incorrect fueling fuel, taking into account the efficiency of the exhaust aftertreatment system 20 the pollutant limit values are met. This means, in particular, that in the case of refueling with fossil diesel fuel, in addition to the speed and torque limitation, a dynamic restriction is provided by delayed and damped release of the setpoint injection quantity with a positive load step in order to keep the particulate matter emissions below the limit of the emission standard to be met. The measures mentioned can also be triggered by the fact that the particle sensor 30 downstream of the SCR catalyst 24 detects an increased particulate emission in the exhaust gas.

In addition, in an internal combustion engine according to the invention 10 upstream and / or downstream of one of the exhaust aftertreatment components 22 . 24 . 38 Exhaust gas for an exhaust gas recirculation can be removed. It is preferred that the exhaust gas upstream of the turbine 26 the exhaust gas turbocharger 18 is removed and via a high pressure exhaust gas recirculation 66 with an exhaust gas recirculation valve 68 with an intake tract immediately upstream of an inlet 78 to the combustion chambers 12 connected is. The exhaust system 16 can also be a low-pressure exhaust gas recirculation 70 comprising the exhaust system downstream of the open particulate filter 22 and downstream of the turbine 26 the exhaust gas turbocharger 18 with a suction line 82 the intake tract 80 of the internal combustion engine 10 upstream of a compressor 84 the exhaust gas turbocharger 18 combines. The low pressure exhaust gas recirculation 70 has a low pressure exhaust gas recirculation line 72 in which a low-pressure exhaust gas recirculation cooler 74 and a low pressure exhaust gas recirculation valve 86 are arranged.

Downstream of the dosing module 28 and upstream of the SCR catalyst 24 can be an exhaust mixer 62 be provided to the mixing of exhaust and reducing agent before entering the SCR catalyst 24 to improve. Furthermore, in the exhaust system 16 downstream of the SCR catalyst 24 a barrier catalyst 64 be provided to prevent uncontrolled ammonia leakage through unused reducing agent.

In 2 is another embodiment of an internal combustion engine 10 represented with an exhaust aftertreatment system according to the invention. With essentially the same structure as 1 In the following, only the differences will be discussed. It is in the exhaust system 16 downstream of the turbine 26 the exhaust gas turbocharger 18 and upstream of the open particulate filter 22 an additional oxygenate storage catalyst 36 , in particular a zeolite storage catalyst, for temporarily storing oxygenates, in particular formaldehyde. This oxygenate storage catalyst 36 is suitable for storing oxygenates in cold conditions and for releasing them again with operating exhaust aftertreatment components. Alternatively to an additional oxygenate storage catalyst 36 a corresponding memory can also be used as an admixture of the noble metal coating on the filter body of the open particle filter 22 be mixed. It has been found that oxygenated compounds in combustion can lead to increased emissions of oxygenates, particularly aldehyde emissions. Therefore, an oxigenate storage catalyst 36 in the form of a zeolite storage catalyst for temporarily storing oxygenates during operation of the internal combustion engine 10 with a special fuel 52 especially advantageous.

Open particle filter 22 can be made in ceramics or metal. Preferred is an embodiment in metal, which in addition an electric heating element 60 having. This allows the open particle filter 22 be electrically heated in certain driving conditions, whereby the oxygenate emissions can be reduced. In particular, an electrically heatable, open particle filter 22 with an upstream oxygenate storage catalyst 36 proposed. This may cause an oxidation function of the open particulate filter 22 before reaching the desorption temperature threshold of the upstream oxygenate storage catalyst 36 achieved and effectively ensured, so that the oxygenate emissions can be effectively reduced.

In 3 is a third embodiment of an internal combustion engine 10 represented with an exhaust aftertreatment system according to the invention. With essentially the same structure as 1 executed, is in the exhaust system 16 downstream of the open particulate filter 22 instead of an SCR catalyst 24 a NOx storage catalyst 38 is arranged. The dosing module is eliminated 28 for introducing the reducing agent.

In 4 is a fourth embodiment of an internal combustion engine 10 shown with an exhaust aftertreatment system according to the invention. With essentially the same structure as 1 executed in this embodiment of the open particle filter 22 downstream of the outlet 14 of the internal combustion engine 10 and upstream of the turbine 26 the exhaust gas turbocharger 18 arranged. Downstream of the turbine 26 are the dosing module 28 for dosing the reductant and further downstream the SCR catalyst 24 arranged.

In 5 is a fifth embodiment of an internal combustion engine 10 represented with an exhaust aftertreatment system according to the invention. With essentially the same structure as 3 listed, in this embodiment, the open particle filter 22 not between the turbine 26 and the NOx storage catalyst 38 but upstream of the turbine 26 arranged.

The admixture of special fuels 52 , in particular of so-called "C1 fuels", ie fuels in which there is no chemical bonding of a carbon atom with another carbon atom, can help to significantly reduce the particulate emissions during combustion. C1 fuels burn virtually soot-free. Even mixtures of C1 fuels with other fuels can disproportionately help the proportion of C1 fuel to lower the raw emissions of the internal combustion engine. Prominent representatives of C1 fuels are oxymethylene ethers (OME). Conventional diesel fuel, biodiesel or paraffinic fuels and esters deviating from biodiesel are particularly suitable as a component of the mixture for the C1 fuel. As proven in several studies, OME fuels offer the possibility of significantly lowering particulate matter emissions in terms of particle mass and particle number compared to the state of the art.

Since the use of pure oxymethylene ether (OME) as fuel is unlikely for reasons of availability and cost, the addition of OME to a conventional (fossil) diesel fuel and a fossil or synthetic paraffinic diesel fuel is the preferred variant of the specialty fuel 52 , As described, disproportionate particle reductions can also be achieved with such mixtures. An admixture of OME, however, measures to compensate for the lower heating value of the OME, such as slightly larger injection holes in the injectors of the injectors 48 , require.

For motor vehicles with diesel engine, which with a special fuel 52 which is a mixture of 5% -100% OME, preferably 10% -99% OME, more preferably 15-70% OME, 0-85% paraffinic diesel fuel, 0-85% fossil diesel fuel, 0-85% biodiesel, 0 - 85% of an alcohol from the group of butanol to hexadecanol and 0 - has 85% furans, therefore, an exhaust gas purification with one of the in 1 to 5 proposed exhaust aftertreatment systems, which effectively the particle number and the NOx emissions of the internal combustion engine 10 lowers.

In 6 is a flow diagram of a method according to the invention for operating an internal combustion engine 10 shown. In this case, in a first method step <100>, the fuel quality of the special fuel 52 checked. Upon detection of incorrect refueling, a warning signal, preferably an optical warning signal, is output by a display in the driving information display in a method step <110> and, in parallel thereto, in a method step <120> appropriate measures for protecting the internal combustion engine 10 and / or the exhaust aftertreatment system 20 initiated. In particular, the available torque, the available power of the internal combustion engine as well as dynamic changes of the injection quantity are restricted to the particle raw emissions of the internal combustion engine 10 lower. In a process step <130> downstream of the open particulate filter 22 , preferably downstream of the SCR catalyst 24 , the particulate emissions in the exhaust system 16 measured and the motor data through the control unit 34 adjusted until the raw emissions of the internal combustion engine 10 are reduced to a minimum, with the exhaust aftertreatment system 20 to comply with the applicable emission limit values. Furthermore, the driver is requested in a process step <140> to do this, corresponding to special fuel 52 to refuel, to the raw emissions of the internal combustion engine 10 lower further. If a different fuel quality is detected, the exhaust gas recirculation via the low-pressure exhaust gas recirculation is also produced in a process step <150> 70 limited or preferably completely suppressed the risk of damage to the compressor 84 the exhaust gas turbocharger 18 to limit.

LIST OF REFERENCE NUMBERS

10

internal combustion engine

12

combustion chamber

14

outlet

16

exhaust system

18

turbocharger

20

aftertreatment system

22

open particle filter

24

SCR catalyst

26

turbine

28

dosing

30

particle sensor

32

signal line

34

control unit

36

Oxigenat storage catalytic converter

38

NOx storage catalytic converter

40

Fuel injection system

42

Fuel line

44

High-pressure fuel pump

46

High-pressure accumulator

48

injector

50

Fuel Supply System

52

Special fuel

54

Fuel line

56

Fuel sensor

58

Fuel tank

60

electric heating element

62

exhaust mixer

64

blocking catalytic converter

66

High-pressure exhaust gas recirculation

68

Exhaust gas recirculation valve

70

Low-pressure exhaust gas recirculation

72

Exhaust gas recirculation line

74

Exhaust gas recirculation cooler

76

Low-pressure exhaust gas recirculation valve

78

inlet

80

intake system

82

suction

84

compressor

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010005813 A1 [0003]
• DE 102015120106 A1 [0004]
• EP 2853707 B1 [0005]

Claims (10)

An internal combustion engine (10) having a fuel system (50) and an exhaust aftertreatment system (20), wherein the exhaust aftertreatment system (20) comprises a particulate reduction unit and an exhaust aftertreatment component downstream of the particulate reduction unit for reducing nitrogen oxide emissions (24, 38), characterized in that the particulate reduction unit is open Particle filter (22) is executed, the internal combustion engine (10) is designed as a self-igniting internal combustion engine (10) according to the diesel principle and with a special fuel (52) is operated, which has at least 5% of a C1 fuel. Internal combustion engine (10) after Claim 1 , characterized in that the C1 fuel is an oxymethylene ether (OME). Internal combustion engine (10) after Claim 1 or 2 , characterized in that the open particulate filter (22) comprises an electrical heating element (60). Internal combustion engine (10) according to one of Claims 1 to 2 , characterized in that the exhaust aftertreatment component for reducing the nitrogen oxide emissions is a NOx storage catalyst (38) or an SCR catalyst (24). Internal combustion engine (10) after Claim 4 , characterized in that the component for reducing the nitrogen oxide emissions as SCR catalyst (24) is formed and downstream of the open particulate filter (22) and upstream of the SCR catalyst (24) a metering module (28) for metering a reducing agent in the Exhaust system (16) is provided. Internal combustion engine (10) according to one of Claims 1 to 5 , characterized in that the open particulate filter (22) in the flow direction of an exhaust gas of the internal combustion engine (10) through an exhaust system (16) of the internal combustion engine (10) is arranged as the first emission-reducing exhaust aftertreatment component. Internal combustion engine (10) according to one of Claims 1 to 6 , characterized in that in the exhaust system (16) of the internal combustion engine (10) an oxygenate storage catalyst (36) is arranged or the open particulate filter (22) is provided with a coating for the storage of oxygenates. Internal combustion engine (10) after Claim 7 , characterized in that the oxygenate storage (36) downstream of the turbine (26) of the exhaust gas turbocharger (18) and upstream of the open particulate filter (22) in the exhaust system (16) of the internal combustion engine (10) is arranged and preferably equipped with a heating device , Method for operating an internal combustion engine according to one of Claims 1 to 8th , characterized in that the particulate matter emissions of the internal combustion engine (10) are lowered by the fact that the special fuel (52) at least 5% of a C1 fuel are admixed. Method according to Claim 9 , characterized in that at the fuel supply system (50) is provided a fuel sensor (56) for detecting the fuel quality, or the engine data of the internal combustion engine (10) by a control unit (34) are evaluated such that the fuel quality is detected, at a Faulty refueling with conventional fossil diesel fuel, the engine parameters of the internal combustion engine (10) are adjusted so that the particulate emissions are lowered below the limit of the emission standard to be met.

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