Method for operating an internal combustion engine using ammonia, internal combustion engine and quick-start device for such an internal combustion engine

Abstract

The invention relates to a method for operating an internal combustion engine using ammonia as fuel, wherein the ammonia is split into at least a hydrogen-nitrogen mixture by means of a cracker, and wherein, when starting the internal combustion engine, a gas containing at least hydrogen is first supplied from a starting storage tank to avoid a starting delay due to the splitting of the ammonia, and then the hydrogen-nitrogen mixture split at the cracker is supplied to the internal combustion engine. The invention further relates to a quick-start device and an internal combustion engine for the direct combustion of ammonia. The invention avoids the disadvantages of the prior art and ensures a low-emission and direct start (quick start) without lengthy preheating measures in an internal combustion engine using ammonia as the sole fuel.

Description

Field of the invention

[0001] The present invention relates to a method for operating an internal combustion engine using ammonia, an internal combustion engine and a quick-start device for such an internal combustion engine. Background of the invention

[0002] Electromobility is reaching its capacity limits, especially in heavy-duty transport where long ranges are concerned. Ships, trains on non-electrified routes, heavy trucks, etc., in particular, are not suitable for everyday use in battery-powered vehicles for the foreseeable future.

[0003] Hydrogen has the disadvantage of poor storage capacity and difficulty in handling by users.

[0004] Ammonia produced without CO2, so-called green ammonia, can also be used as an electricity-based fuel and offers the advantage that it can be stored and transported cost-effectively in liquid form, does not require a carbon source and thus remains CO2-neutral and is available on an industrial scale.

[0005] When ammonia is burned under optimal conditions, only water and nitrogen are produced. A disadvantage compared to conventional fuels is the poor flammability and low flame speed of ammonia-air mixtures, which makes their use in heat engines difficult. To overcome this disadvantage, a small amount of hydrogen can be added to the ammonia, whereby the hydrogen essentially acts as an igniter for the low-combustibility ammonia. Mixing ratios of 4:1 to approximately 10:1, based on the energy content, between ammonia and hydrogen are possible to obtain a combustible gas mixture for operating a heat engine. Combustion of pure ammonia is also possible, but results in losses in power and efficiency.

[0006] EP 3 859 138 A1 discloses a method for operating a diesel engine as a dual-fuel engine using two different fuels, with diesel or heavy fuel oil serving as the first fuel. A gaseous fuel consisting of a mixture of ammonia and hydrogen is used as the second fuel, with the gas mixture being ignited by injecting a small amount of diesel oil as ignition oil. However, such dual-fuel systems also require the refueling of two separate tank systems with different fuel types, which limits or even prevents handling in some applications.

[0007] Hydrogen can be produced from ammonia itself, as disclosed, for example, in EP 3 028 990 A1. This means that only ammonia is used as a fuel. Hydrogen is produced using an energy-autonomous fission reactor that splits ammonia with high efficiency into the elements 2 NH3 => 3 H2 + N2. The resulting gas mixture contains 75% hydrogen and 25% nitrogen. This converts ammonia, which in practice is hardly usable as a fuel, into a highly flammable gas. The hydrogen thus obtained is added to the main stream of ammonia, and the gas mixture can be used as fuel in heat engines as usual. The residual nitrogen can undergo the combustion process as an inert gas.

[0008] When using a fuel system that uses only ammonia as fuel, additional measures are required, particularly when starting and operating a cold engine. For large engines or for marine propulsion, for example, upstream stationary cracking units for the (partial) splitting of the NH3 into H2 and N2, as well as preheaters for engine operation, are known. The crackers used in this case are heated externally, electrically or via burners. Alternatively, there are also concepts that use the engine's exhaust gas temperature for heating. In mobile applications, for example in motor vehicles, there is also a requirement for quick startability and low-emission engine warm-up. Long preheating phases are often not possible in these cases.

[0009] In particular, the first few seconds after the engine starts usually have a decisive influence on the engine's emissions. Summary of the invention

[0010] It is therefore the object of the present invention to propose a method and a device which avoid the disadvantages of the aforementioned prior art and ensure a low-emission and direct start (quick start) without lengthy preheating measures in an internal combustion engine using ammonia as the sole fuel.

[0011] This object is achieved by a method for operating an internal combustion engine using ammonia as fuel having the features of claim 1, a quick-start device for an internal combustion engine for directly combusting ammonia having the features of claim 10, and an internal combustion engine for directly combusting ammonia having the features of claim 20. Advantageous developments and embodiments of the invention are specified in the dependent claims.

[0012] The method according to the invention for operating an internal combustion engine using ammonia as fuel, wherein ammonia is cracked into at least a hydrogen-nitrogen mixture by means of a cracker, initially comprises at least one gas containing hydrogen and nitrogen when the internal combustion engine is started, which gas is supplied from a start-up reservoir in order to avoid a start-up delay due to the cracking of the ammonia, and wherein the hydrogen-nitrogen mixture cracked in the cracker is then supplied to the internal combustion engine. In this case, the gas may, in addition to hydrogen and nitrogen, optionally also contain residual ammonia that was not fully converted in the cracker. Due to the method according to the invention, no additional fuels are required, and the internal combustion engine can be operated exclusively with ammonia.The method according to the invention avoids the disadvantages of the aforementioned prior art and ensures a low-emission and direct start (quick start) without lengthy preheating measures in an internal combustion engine using ammonia as the sole fuel.

[0013] An advantageous embodiment of the process according to the invention provides that any ammonia remaining after cracking is condensed out and returned to the cycle. The advantage of this condensation is that, after the cracker, an H2 / N2 mixture that is up to 100% ammonia-free is present.

[0014] An advantageous embodiment of the process according to the invention provides for a high-pressure evaporator and a high-pressure cracker. The advantage here is that the compressed liquid ammonia present in the tank can now be passed through the high-pressure cracker in gaseous form, virtually maintaining the previously generated pressure level.

[0015] Another advantageous embodiment of the method according to the invention provides that, alternatively or in addition to the high-pressure evaporator and high-pressure cracker, a low-pressure evaporator and a low-pressure cracker are provided. This low-pressure path then has the function of splitting the ammonia for the majority of the required injection quantity for operating the internal combustion engine into a proportional amount of an H2 / N2 mixture based on the total amount of fuel downstream in the cracker path.

[0016] A further advantageous embodiment of the process according to the invention provides that part of the hydrogen-nitrogen mixture produced in the cracker is stored in the starting accumulator. The other part of the mixture is fed to the engine via direct injection.

[0017] Yet another advantageous embodiment of the method according to the invention provides for liquid ammonia to be stored in at least one high-pressure ammonia tank. This allows not only a higher storage density but also compression of the ammonia to the required injection pressure in the liquid phase, thus achieving energy savings.

[0018] Yet another advantageous embodiment of the method according to the invention provides that the at least one cracker is heated via an exhaust gas heat exchanger and / or an electric heater. This enables the cracker to heat up quickly and with low energy consumption.

[0019] Yet another advantageous embodiment of the method according to the invention provides that the high-pressure ammonia tank has an additional internal ammonia tank. This ensures that, regardless of the fill level of the main tank, the ammonia pressure is sufficient to fill the starting reservoir.

[0020] Finally, a further advantageous embodiment of the method according to the invention provides for a high-pressure direct injection and / or a low-pressure fuel rail injection.

[0021] The quick start device according to the invention for an internal combustion engine for directly burning ammonia comprises a high-pressure ammonia tank, an evaporator, a cracker connected thereto, a fuel injection system of the internal combustion engine and a start accumulator.

[0022] An advantageous embodiment of the quick-start device according to the invention provides that the starter reservoir has a pressure of 1 bar to 40 bar, preferably 3 bar to 20 bar. 3 bar represents the lower pressure when the starter reservoir is almost empty. The pressure of 20 bar is the upper pressure when the starter reservoir is full. In non-supercharged engines, the lower pressure could be reduced to as low as 1 bar. At a pressure of up to 40 bar, the condensation temperature could be increased to approximately 80°C, which could potentially be advantageous for reliable condensation in the high-pressure cooler.

[0023] A further advantageous embodiment of the quick-start device according to the invention provides that the starting accumulator has a volume of 3 liters to 30 liters, preferably 5 liters to 15 liters. The size of the starting accumulator volume is determined not only by the maximum accumulator pressure, but also by the heating time of the cracker path(s) and the available installation space.

[0024] Another advantageous embodiment of the quick-start device according to the invention provides that the starting reservoir is connected to a cracker. This cracker supplies a proportional amount of an H2 / N2 mixture to the starting reservoir.

[0025] Yet another advantageous embodiment of the quick-start device according to the invention provides for a two-way valve for filling, emptying, and closing the starting reservoir. A control valve is also conceivable for this purpose, enabling gradual opening, thus avoiding a sudden drop in pressure. The advantage of this also lies in the possibility of specifically applying the pressure behavior of the injection path when switching to the various operating modes of the internal combustion engine.

[0026] Yet another advantageous embodiment of the quick-start device according to the invention provides for an additional pump to fill the starter reservoir. By using such an additional pump, a starter reservoir could be filled and used even if the high-pressure cracker path were eliminated.

[0027] Yet another advantageous embodiment of the quick-start device according to the invention provides for a filling device for externally filling the starter reservoir. Externally filling the starter reservoir also allows for a comparatively simple retrofitting of the quick-start device into an internal combustion engine with an existing low-pressure system.

[0028] Yet another advantageous embodiment of the quick-start device according to the invention provides that the starter reservoir can be filled with a gas mixture comprising hydrogen and nitrogen and, when filled, at a pressure of 20 bar to 40 bar and / or a temperature of up to 80°C. This provides sufficient time to bring the cracker system(s) to operating temperature during low-emission engine operation.

[0029] Yet another advantageous embodiment of the quick-start device according to the invention provides that the fuel injection system is provided as a port injection.

[0030] Finally, a further advantageous embodiment of the quick-start device according to the invention provides that the fuel injection system is provided as a direct injection.

[0031] The internal combustion engine according to the invention for the direct combustion of ammonia provides the quick start device according to the invention described above. Short description of the characters

[0032] Further measures improving the invention are presented in more detail below together with the description of preferred embodiments of the invention with reference to the figures.

[0033] It shows Fig. 1 schematic representation of an internal combustion engine according to the invention with a quick-start device and integration into the exhaust gas aftertreatment system as well as with component groupings of the two fuel paths according to a first embodiment; Fig. 2 schematic representation of the internal combustion engine according to the invention with quick start device with integration into the exhaust gas aftertreatment according to the first embodiment; Fig. 3 schematic representation of the internal combustion engine according to the invention with quick start device according to the first embodiment; Fig. 4 Overview table of internal combustion engines according to the invention with quick start device, which shows parameters of injection, temperature and pressure ranges and switching positions of various valves according to the first embodiment; Fig. 5 schematic representation of an internal combustion engine according to the invention with quick start device and a large high-pressure cracker and 3 bar / 20 bar injection DI according to a second embodiment; Fig. 6 shows a schematic representation of an internal combustion engine according to the invention with a quick-start device and a large high-pressure cracker and 3 bar injection PI according to embodiment 3a; an internal combustion engine according to the invention with a quick-start device and only one large high-pressure cracker and 3 bar injection DI according to embodiment 3b; Fig. 7 schematic representation of an internal combustion engine according to the invention with a quick-start device and a large low-pressure cracker and compressor and 3 bar injection PI (embodiment 4a); only with low-pressure cracker and compressor and 3 bar injection DI (embodiment 4b); Fig. 8a and Fig. 8b schematic representation of an internal combustion engine according to the invention with quick start device and second fuel tank according to a fifth embodiment. Detailed description of the embodimentsEmbodiment 1

[0034] In a first embodiment according to Fig. 1, the internal combustion engine according to the invention has a quick-start device with a connected starter reservoir 1. The starter reservoir 1 preferably has a volume of 5 to 15 liters and is shown in a design suitable for hydrogen storage. To achieve the lowest possible weight with high rigidity, fiber composite materials, for example, made of carbon fibers, are preferably used.

[0035] In this exemplary embodiment, the start-up accumulator 1 is filled with an H2 / N2 mixture metered up to 100% via the high-pressure cracker path before the internal combustion engine is switched off when the engine is at operating temperature. For this purpose, a 2-way valve V-SS1 or a control valve is connected upstream of the start-up accumulator 1. The high-pressure cracker draws the ammonia from the high-pressure ammonia tank >20 bar 2. The pressure in the high-pressure tank 2 is selected such that ammonia in the high-pressure tank 2 is preferably present in the liquid phase. The high-pressure tank 2 optionally has an additional inner ammonia tank >20 bar 3. If the pressure in the high-pressure tank 2 is lower than that intended for the start-up accumulator 1, the inner ammonia tank >20 bar 3 is brought to the pressure level intended for the high-pressure cracker path using a partial quantity of the fuel using a fuel pump. This pressure level is in the range of approximately 20 bar to 40 bar.

[0036] A high-pressure evaporator 8 is arranged downstream of the high-pressure tank 2. In the high-pressure evaporator 8, the liquid ammonia is converted into the gas phase by the addition of thermal energy, for example, from the HP-C cooler downstream of the cracker 4, and is fed to the high-pressure cracker 4 as preferably superheated dry steam. The ammonia is at almost the same pressure at which it leaves the fuel tank 2 or the internal fuel tank 3. This pressure level is in the range of approximately 20 bar to 40 bar.

[0037] In the high-pressure cracker 4, the ammonia is split into its components H2 and N2 at high temperatures, as described above. Residual ammonia can also leave the high-pressure cracker 4. The high-pressure cracker 4 is preferably designed as a countercurrent gas / gas heat exchanger. This design allows high efficiencies to be achieved in a small installation space. In the present embodiment, the high-pressure cracker 4 is coated with nickel or cobalt, for example. A temperature level of greater than 600 °C is selected, as the best cracker efficiencies are achieved with a nickel coating.

[0038] In the downstream high-pressure cooler HP-C, the hydrogen-nitrogen-ammonia gas mixture is cooled below the ammonia's condensation temperature, and the liquefied ammonia is fed back into the upstream path. The now highly dosed H2 / N2 gas mixture is then released via the fuel rail of high-pressure path 17 by direct injection. For this purpose, the 2-way valve upstream of fuel rail 17 is switched to the P-DI high-pressure regulator at approximately 20 bar.

[0039] At the same time, the starting storage 1 is filled with the H2 / N2 gas mixture until the starting storage is completely filled.

[0040] The injection of the H2 / N2 gas mixture via the injectors of the fuel rail 17 into the internal combustion engine takes place in the “engine operation warm” mode described above, as in Fig. 4, as a pilot injection of a portion of the fuel required to operate the internal combustion engine during the compression phase and also serves as a catalytic converter post-heating injection during the exhaust phase of the internal combustion engine.

[0041] Injection management via the high-pressure cracker path achieves excellent ignition behavior of the H2 / N2 gas mixture in the internal combustion engine. In the illustrated embodiment, the internal combustion engine has an additional, so-called low-pressure cracker path in addition to the high-pressure cracker path described above.

[0042] The low-pressure cracker path is also connected to the ammonia high-pressure tank >20 bar 2 and, in addition to pressure regulators and other components, has a low-pressure evaporator 7 downstream of the high-pressure tank 2, a low-pressure cracker 5 downstream of this, a low-pressure cooler downstream of this, and a fuel rail 14 with the port injection injectors.

[0043] The main fuel quantity of the internal combustion engine is then injected via this low-pressure cracker path. The low-pressure cracker 5 is preferably also designed as a countercurrent gas / gas heat exchanger. Since the requirements for the degree of cracking, and thus the proportion of the H2 / N2 mixture in the total amount of fuel downstream of the cracker path, are lower for the main fuel quantity of the low-pressure cracker path than for the high-pressure cracker path, the low-pressure cracker 5 can be initially ready for operation at lower temperatures starting at approximately 450°C.

[0044] In the “engine stop” mode of the internal combustion engine according to Fig. 4, the starting reservoir 1 is closed via the upstream valve V-SS1.

[0045] In the subsequent "engine start" mode, the start accumulator 1 is now opened via the upstream valve V-SS1. This enables the injection of the gaseous, highly dosed H2 / N2 mixture via the fuel rail 17 of the high-pressure path by means of direct injection, primarily into the intake phase and temporarily also into the exhaust phase of the internal combustion engine.

[0046] For this purpose, the 2-way valve upstream of fuel rail 17 is switched to the P-DI low-pressure regulator at approximately 3 bar to allow the starting accumulator 1 to be drained to this pressure. This continues until the high-pressure cracker 4 has reached its operating temperature of greater than approximately 600 °C. This duration depends on the internal combustion engine used and the overall packaging in the vehicle and will take less than 60 seconds.

[0047] If the downstream low-pressure cracker 5 has also reached a temperature of greater than approximately 450°C and thus a sufficient degree of splitting of ammonia into H2 / N2 components for the main fuel mixture is achieved, the following four states occur simultaneously or in short intervals: 1. The high-pressure cracker path is released by switching the 2-way valve V-HP1 to the start accumulator 1 and the fuel rail 17. 2. The starting reservoir 1 is closed via the valve V-SS1. 3. The pilot injection with switching to the pressure regulator P-DI-high is activated. 4. The low-pressure cracker path is released by switching the valve V-LP1 of the fuel rail 14, so that a port injection of the main fuel quantity of the internal combustion engine takes place.

[0048] The internal combustion engine now operates in parallel with both injection paths (14 and 17). The internal combustion engine is now back in "engine warm operation" mode ( Fig. 4), whereby by opening the valve V-SS1 or by opening an alternative control valve, the starting reservoir 1 can be filled repeatedly for a next new start-up process.

[0049] The high-pressure cracker is heated via a heat exchanger by integrating the high-pressure cracker 4 into the exhaust gas line of the internal combustion engine and via an electric heater 6 of the high-pressure cracker 4. For this purpose, the high-pressure cracker 4 is installed downstream of the engine-mounted oxidation catalyst 9.

[0050] If necessary, a connection to an exhaust gas bypass 10 is made here in order to focus the heating measures specifically on the cracker path and to prevent the downstream catalysts 11 and 12 from being permanently exposed to excessively high temperatures.

[0051] The low-pressure cracker 5 is located downstream of the high-pressure cracker 4 in the exhaust system. It is also preferably designed as a counterflow gas / gas heat exchanger.

[0052] The optional electric heater 6 serves to support the heating or preheating of the cracker systems 4; 5, especially when the starter storage is not sufficiently filled for an existing engine start.

[0053] Due to the higher levels of nitrogen oxide (NOX) in the exhaust gases caused by the use of ammonia as a fuel, special measures for exhaust gas purification can be implemented. In the version shown here, the exhaust aftertreatment system includes several catalysts: A close-coupled oxidation catalyst 9 serves not only to heat the cracker but also to oxidize any unburned ammonia. It is preferably coated with a platinum-palladium group to enable early catalyst activation.

[0054] A downstream SCR catalyst 11 reduces the nitrogen oxide NOx produced during the combustion process by adding small amounts of ammonia. The ammonia is added via residual amounts of unburned ammonia from the combustion process via the exhaust system 13 and / or by adding adjusted amounts upstream of the SCR catalyst 11 from the high-pressure ammonia tank 2.

[0055] A downstream optional ammonia slip catalyst (ASC-Oxi) 12 ensures low-N2O oxidation in the event of ammonia slip from the SCR catalyst 11. It is also designed as an oxidation catalyst and has a coating spectrum that reduces the formation of N2O.

[0056] In the version 1 shown here, evaporators 7, 8, crackers 4, 5, and the two coolers HP-C and LP-C are designed in the component groups A, B, C and A+C. These component groups are in Fig. 1 with a dashed line and labeled with the letters A, B, C, or A+C. The illustrated groupings A, B, and C are implemented, for example, by using common components, such as a housing, each with a high-pressure and low-pressure connection. Or by combining several components into one, such as A+C, with A (evaporator 7 and / or 8) and C (cooler LP-C and / or HP-C).

[0057] This can bring advantages in terms of installation space, costs and efficiency in the respective designs.

[0058] Fig. 2 shows the schematic representation of the internal combustion engine according to the invention with quick start device with integration into the exhaust gas aftertreatment according to the first embodiment.

[0059] Fig. 2 shows the embodiment 1 as already shown in Fig. 1, where the individual components (evaporators 7, 8, crackers 4, 5), and the two coolers (HP-C and LP-C) are not grouped together and therefore not designed as shared components. This can provide advantages for specific installation conditions in the intended application / vehicle, for example, should shared components require significant modifications to other existing components of the internal combustion engine due to their larger size.

[0060] Fig. 3 shows the schematic representation of the internal combustion engine according to the invention with quick start device according to the first embodiment, wherein the integration into the exhaust gas aftertreatment is not shown here. Embodiment 2

[0061] Fig. Figure 5 shows a schematic representation of an internal combustion engine according to the invention with a quick-start device and a large high-pressure cracker 4 and 3 bar / 20 bar injection DI according to embodiment 2. In contrast to the first embodiment, this embodiment does not have a second low-pressure cracker path. In the second embodiment, the entire fuel quantity to be injected is injected via the high-pressure cracker path via the injectors of the fuel rail 17. Embodiment 3a and 3b

[0062] Fig. 6 shows a schematic representation of an internal combustion engine according to the invention with a quick-start device and a large high-pressure cracker 4 and 3 bar injection PI via the injectors of the fuel rail 17 according to embodiment 3a; an internal combustion engine according to the invention with a quick-start device and only one large high-pressure cracker 4 and 3 bar injection DI via the injectors of the fuel rail 17 according to embodiment 3b. Embodiments 4a and 4b

[0063] Fig. Figure 7 shows a schematic representation of an internal combustion engine according to the invention with a quick-start device and a large low-pressure cracker 5 and compressor 15, and 3 bar injection PI via the injectors of the fuel rail 14 (embodiment 4a); with only a low-pressure cracker and compressor and 3 bar injection DI via the injectors of the fuel rail 14 (embodiment 4b); Embodiment 5

[0064] Fig. 8a and Fig.8b shows the schematic representation of an internal combustion engine according to the invention with a quick-start device and a second fuel tank 16 and a compressor 15 according to embodiment 5. The injection of the fuel quantity when the quick-start device is switched off takes place via a separate low-pressure cracker path with a high-pressure tank 2, evaporator 7, low-pressure cracker 5, and injectors of the fuel rail 14 as direct injection or as port injection. List of reference symbols 1 startup memory 2 ammonia high pressure tank >20 bar 3 Internal ammonia tank >20 bar 4 high-pressure crackers 5 low-pressure crackers 6 electric heaters 7 low-pressure evaporators 8 high-pressure evaporators 9 Oxi catalyst 10 Bypass temperature control NH3 cracker and SCR-ASC 11 SCR 12 ASC-Oxi 13 Exhaust 14 Fuelrail low-pressure cracker path 15 Additional pump 16 Second fuel tank 17 Fuelrail High Pressure Cracker Path QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This 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

[0000] EP 3 859 138 A1

[0006] EP 3 028 990 A1

[0007]

Claims

[1] Method for operating an internal combustion engine using ammonia as fuel, wherein ammonia is cracked into at least a hydrogen-nitrogen mixture by means of a cracker, and wherein when starting the internal combustion engine, a gas containing at least hydrogen is first supplied from a start-up storage in order to avoid a start-up delay due to the cracking of the ammonia, and then the hydrogen-nitrogen mixture cracked at the cracker is supplied to the internal combustion engine. [2] Process according to claim 1, wherein after the cracking by means of a cracker, any ammonia still present is condensed out and returned to the cycle. [3] A process according to claim 1 or 2, wherein a high pressure evaporator and a high pressure cracker are provided. [4] Process according to claims 1 to 3, wherein a low-pressure evaporator and a low-pressure cracker are provided. [5] A process according to claims 1 to 4, wherein a portion of the hydrogen-nitrogen mixture produced in the cracker is stored in the starting storage. [6] A method according to claims 1 to 5, wherein liquid ammonia is stored in at least one high-pressure ammonia tank. [7] Process according to claims 1 to 6, wherein the at least one cracker is heated via an exhaust gas heat exchanger and / or an electric heater. [8] The method of claim 1 to 7, wherein the high pressure ammonia tank comprises an additional inner ammonia tank. [9] Method according to claims 1 to 8, wherein a high-pressure direct injection and / or a low-pressure fuel rail injection is provided [10] A quick start device for an internal combustion engine for directly burning ammonia, the device comprising a first ammonia storage, an evaporator, a cracker connected thereto, a fuel injection system of the internal combustion engine and a start storage. [11] Quick start device according to claim 10, wherein the starting accumulator has a pressure of 1 bar to 40 bar, preferably 3 bar to 20 bar. [12] Quick start device according to claim 10 or 11, wherein the starting accumulator has a volume of 3 liters to 30 liters, preferably 5 liters to 15 liters. [13] A quick start device according to claim 10 to 12, wherein the start memory is connected to a cracker. [14] Quick start device according to claims 10 to 13, wherein a two-way valve is provided for filling, emptying and closing the starting accumulator. [15] Quick start device according to claim 10 to 14, wherein an additional pump is provided for filling the start accumulator. [16] Quick start device according to claim 10 to 15, wherein a filling device is provided for externally filling the starting accumulator. [17] Quick start device according to claims 10 to 16, wherein the start accumulator can be filled with a gas mixture which comprises hydrogen and nitrogen and, when filled, can be filled at a pressure of 20 bar to 40 bar and a temperature of up to 80°C. [18] Quick start device according to claims 10 to 17, wherein the fuel injection system is provided as a port injection. [19] Quick start device according to claims 10 to 18, wherein the fuel injection system is provided as a direct injection. [20] Internal combustion engine for the direct combustion of ammonia with a quick start device according to claims 10 to 19.

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