Gas power cycle arrangement with internal combustion engine and method for providing a gas power cycle arrangement

Abstract

A monoatomic-gas power cycle arrangement is described including an internal combustion engine (103) adapted for combusting a fuel (132) in a mixture with a monoatomic gas (130) and having an inlet (121) for receiving the monoatomic gas and an exhaust outlet (122) for letting out an exhaust product (133); and a gas-recycling conduit system (101), the gas-recycling conduit system (101) extending from the exhaust outlet (122) to the inlet (121) for transporting the monoatomic gas (130) from the outlet (122) to the inlet (121) thereby forming a loop. The gas-recycling conduit system (101) includes a separating unit (105) for separating the monoatomic gas (130) from the combustion product, and a turbomachine unit (110) for the internal combustion machine with a turbine (111) to be driven by the exhaust product, and a compressor (112) for compressing the monoatomic gas. Further, a method for providing a monoatomic-gas power cycle arrangement is described.

Description

[0001] Gas power cycle arrangement with internal combustion engine and method for providing a gas power cycle arrangement

[0002] Aspects of the invention relate to a gas power cycle arrangement, in particular a gas power cycle arrangement with an internal combustion engine arranged within the cycle. Further aspects relate to a method for providing a gas power cycle arrangement, especially a gas power cycle arrangement with an internal combustion engine.

[0003] Technical background:

[0004] Internal combustion engines use fuel and oxygen for the combustion. In an open cycle, the oxygen from the ambient air is drawn into the internal combustion engine to enable the combustion of the fuel. In other words, the air is continuously taken from the outside of the internal combustion engine to be present in the combustion process. Afterwards, the exhaust product is led out of the internal combustion engine and, especially, out of the complete engine system.

[0005] In a closed cycle internal combustion engine, a working fluid is running in a cycle including the internal combustion engine and an exhaust gas separator. The exhaust gas separator may separate the combustion product from the working fluid so that the working fluid can stay in the cycle. The fuel as well as the oxygen is added at defined positions in the cycle. For instance, the fuel is directly added at the internal combustion engine.

[0006] However, the closed cycle internal combustion engine brought by the current state of the art represent a high CAPEX (capital expenditure) effort, even if OPEX (operating expense) cost reduction compensates this after a period. The cost reduction, on the other hand, depends and varies according to the specific case.

[0007] Thus, there is a need for improving the CAPEX-OPEX situation for a closed cycle internal combustion engine using a working fluid. Summary of the invention

[0008] In view of the above, a monoatomic gas power cycle arrangement according to claim 1, and a method for providing a monoatomic gas power cycle arrangement according to claim 12 are provided.

[0009] According to an aspect, a monoatomic-gas power cycle arrangement is provided. The monoatomic-gas power cycle arrangement includes an internal combustion engine having a combustion chamber adapted for combusting a fuel in a mixture with a monoatomic gas and having an inlet for receiving the monoatomic gas and an exhaust outlet for letting out an exhaust product including the monoatomic gas mixed with a combustion product resulting from the combustion in the combustion chamber. The monoatomic-gas power cycle arrangement further includes a gas-recycling conduit system for the monoatomic gas, the gas-recycling conduit system extending from the exhaust outlet to the inlet for transporting the monoatomic gas from the exhaust outlet back to the inlet, thereby forming a loop for the monoatomic gas. The gasrecycling conduit system includes a separating unit for separating the monoatomic gas from the combustion product and for removing partially or completely the combustion product from the gas-recycling conduit system, and a turbomachine unit connected to the internal combustion machine with a turbine arranged to be driven by the exhaust product upstream of the separating unit, and with a compressor arranged for compressing the monoatomic gas downstream of the separating unit (eventually mixed with an oxidizing agent and / or fuel downstream of the separating unit). The turbomachine unit includes at least one of a wastegate, a compressor bypass, an engine by-pass, multi-entry turbine(s), a variable turbine geometry, a variable compressor geometry, multiple turbocharging units, and an electrically assisted turbomachine unit.

[0010] Generally, an internal combustion engine power cycle using a monoatomic gas as a cycling gas is able to achieve a higher thermal efficiency according to embodiments described herein. In particular, using a monoatomic gas (instead of e.g. Nitrogen) has the advantage of a higher specific heat ratio. A higher specific heat ratio of the cycling gas improves the thermal efficiency of the internal combustion engine, especially by increasing the efficiency of the engine's internal thermodynamic process. A higher efficiency, on the other hand, may reduce the amount of fuel used for operating the internal combustion engine, and, consequently, operation costs.

[0011] Additionally, the monoatomic gas power cycle arrangement according to embodiments described herein may be driven with low emissions, or even (almost) zero emissions, especially regarding NOXor COXemissions (depending on the fuel used in the internal combustion engine). Using a monoatomic gas in the cycle arrangement for an internal combustion engine helps avoiding NOXproduction in the exhaust part of the cycle. Typically, the monoatomic gas power cycle arrangement according to embodiments described herein using a monoatomic gas as a working fluid helps reducing environmentally relevant emissions.

[0012] According to some embodiments, the monoatomic gas power cycle arrangement as described herein is able to actively control the pressure and temperature level before the separating unit, especially by using the turbomachine unit. The control of the temperature and pressure of the exhaust product before or in the separating unit is advantageous regarding affecting the dew point in the separating unit. Affecting the dew point in the separating unit influences the efficiency and reliability of the separating unit.

[0013] According to an aspect, there is provided a method for providing a monoatomic-gas power cycle arrangement for combusting a fuel in a mixture with a monoatomic gas in an internal combustion engine is provided. The internal combustion engine includes an inlet for receiving the monoatomic gas and an exhaust outlet for letting out an exhaust product including the monoatomic gas mixed with a combustion product resulting from the combustion in the combustion chamber. The method includes providing a gas-recycling conduit system for the monoatomic gas, the gas-recycling conduit system extending from the exhaust outlet to the inlet for transporting the monoatomic gas from the exhaust outlet back to the inlet thereby forming a loop for the monoatomic gas; passing the gas-recycling conduit system for the monoatomic gas through a separating unit for separating partially or completely the monoatomic gas from the combustion product; and equipping the gas-recycling conduit system with a turbomachine unit and connecting the turbomachine unit to the internal combustion engine, the turbomachine unit including a turbine arranged to be driven by the exhaust product upstream of the separating unit, and including a compressor arranged for compressing the monoatomic gas with eventually the fuel and / or an oxidizing agent downstream of the separating unit. Equipping the internal combustion engine with a turbomachine unit includes equipping the internal combustion engine with at least one of a wastegate, a compressor by-pass, an engine by-pass, multi-entry turbine(s), a variable turbine geometry, a variable compressor geometry, multiple turbocharging units, and an electrically assisted turbomachine unit.

[0014] Equipping the gas-recycling conduit system with a turbomachine unit and connecting the turbomachine unit to the internal combustion engine according to embodiments described herein improves the thermal efficiency and may also (depending on the turbomachine type) control the pressure and temperature levels before the separating unit. The pressure level upstream of the separating unit (and, consequently, temperature and pressure in the separating unit) influences and is able to control the dew point. A control of the dew point in the separating unit allows aligning the operation of the system to the operational requirements of the separating unit. The efficiency of the separating unit, and, generally of the complete cycle arrangement can be improved.

[0015] Further advantages, features, aspects and details that can be combined with embodiments described herein are evident from the dependent claims, the description and the drawings.

[0016] Brief description of the Figures:

[0017] The details will be described in the following with reference to the figures, wherein

[0018] Fig. 1 is a schematic view of the monoatomic gas power cycle arrangement with a turbomachine unit according to embodiments described herein;

[0019] Fig. 2 is a schematic view of the monoatomic gas power cycle arrangement with a turbomachine unit with a wastegate according to embodiments described herein;

[0020] Fig. 3 is a schematic view of the monoatomic gas power cycle arrangement with a turbomachine unit with a variable turbine geometry of any kind, including multientry turbines with the possibility to close, at least partially, at least one entry according to embodiments described herein;

[0021] Fig. 4 is a schematic view of the monoatomic gas power cycle arrangement with an electrically assisted turbomachine unit according to embodiments described herein; Fig. 5 is a schematic view of the monoatomic gas power cycle arrangement with an electrically assisted un-shafted turbomachine unit according to embodiments described herein; and,

[0022] Fig. 6 is a flowchart of a method for providing a monoatomic-gas power cycle arrangement according to embodiments described herein.

[0023] Detailed description of the Figures and of embodiments:

[0024] Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in each figure. Each example is provided by way of explanation and is not meant as a limitation. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with any other embodiment to yield yet a further embodiment. It is intended that the present disclosure includes such modifications and variations.

[0025] Within the following description of the drawings, the same reference numbers refer to the same or to similar components. Generally, only the differences with respect to the individual embodiments are described. Unless specified otherwise, the description of a part or aspect in one embodiment applies to a corresponding part or aspect in another embodiment as well.

[0026] Figure 1 shows a monoatomic gas power cycle arrangement 100 according to some embodiments described herein. Typically, the monoatomic gas power cycle arrangement 100 includes a gas-recycling conduit system 101, an internal combustion engine 103, a separating unit 105 for separating the monoatomic gas 130 from the combustion product, and a turbomachine unit 110 including a turbine 111 and a compressor 112.

[0027] According to some embodiments, the monoatomic gas power cycle arrangement as described herein may be used for a variety of different fuel types. In particular, when the monoatomic gas power cycle arrangement is used with a fuel like hydrogen, the monoatomic gas power cycle arrangement may be used as an alternative to fuel cells (such as PEM-type fuel cells). Typically, the monoatomic gas power cycle arrangement according to some embodiments described herein may eliminate the use of high-purity hydrogen, as used in fuel cells, and, typically, eliminates the use of costly materials used for fuel cells (such as Pt for the anode for instance). Generally, the operation of the monoatomic gas power cycle arrangement having an internal combustion engine according to embodiments described herein is easier and less complex compared to the operation of a fuel cell.

[0028] The internal combustion engine 103 of the gas power cycle arrangement 100 according to some embodiments described herein has a combustion chamber adapted for combusting a fuel 132 in a mixture with the monoatomic gas 130. In particular, an oxidizing agent 131 is added for the combustion process. According to some embodiments, the oxidizing agent 131 is mixed with the monoatomic gas before the combustion process. In some embodiments, a gas mixer unit

[0029] 102 is provided for mixing the monoatomic gas with the oxidizing agent 131. Typically, the gas mixer unit 102 may be placed at an arbitrary position before the internal combustion engine

[0030] 103 in the gas-recycling conduit unit 101 (more details will be explained below).

[0031] Typically, the internal combustion engine 103 has an inlet 121 for receiving the monoatomic gas 130, which is possibly mixed with the fuel and / or other input gases, such as an oxidizing agent. The inlet 121 may especially be adapted for passing the monoatomic gas or the mixture into the combustion chamber of the internal combustion engine. In some embodiments, the internal combustion engine 103 may have different inlets for the gas mixture (typically including the monoatomic gas and the oxidizing agent) and for the fuel to be introduced into the combustion chamber. Typically, four introduction possibilities may be used in some embodiments described herein: a first option may include the introduction by direct injection of a fuel at high pressure (such as in a Diesel cycle); a second option may include introduction by direct injection of a gas or liquid fuel at lower pressure (such as in a Otto- Beau de Rochas cycle, especially compared to the Diesel cycle); a third option may include indirect injection, where fuel is injected somewhere upstream of the internal combustion engine (e.g. upstream or downstream the compressor), in particular in a "pre-mixed" mode (such as in an Otto - Beau de Rochas cycle), and a fourth option may include introduction by indirectly injecting the fuel into a dedicated port, with or without some gas and oxidizing agent.

[0032] According to embodiments described herein, the internal combustion engine has an exhaust outlet 122 for letting out the monoatomic gas mixed with a combustion product resulting from the combustion in the combustion chamber. Typically, the monoatomic gas mixed with a combustion product may be denoted as an exhaust product 133. The exhaust product 133 may be guided within the gas recycling conduit unit 101, especially away from the internal combustion engine 103, which may especially be seen by the arrows of circulation in the gas recycling conduit unit 101 in Figure 1. In some embodiments, the internal combustion engine is adapted for combusting fuels in the combustion chamber including hydrogen, methane, methanol, ammonia, e-fuels, and / or a fuel having the general formula CmHnOpNq. Typically, the indices m, n, p, and q of the formula CmHnOpNqmay range from typically between 0 and 30, more typically between 0 and 28, and even more typically between 0 and 26. According to some embodiments, the general formula CmHnOpNqmay include fuels such as exemplarily H2, NH3, CH4, CH4O, C7HI6, and / or CI2H26. According to some embodiments, the internal combustion engine may also be adapted for combusting NG (natural gas), BG, coke gas, diesel, and / or Biodiesel. According to some embodiments described herein, which may be combined with other embodiments described herein, the internal combustion engine may be adapted for (typically any) liquid fuel, (typically any) solid fuel (for instance for injecting powders, like for example coal, into a Diesel engine), or (typically any) gaseous fuel (such as fuels for multi-fuel process and the like). The internal combustion engine may be adapted to such fuels e.g. by the materials used, the construction kind, the heat resistance, the operation control, the inlet system for the fuel, the exhaust system for the combustion product, and the like.

[0033] The gas-recycling conduit unit 101 is in particular a kind of conduit, pipe, or duct, in which the monoatomic gas for the combustion process of the gas power cycle arrangement is guided. In some embodiments, the monoatomic gas in the gas-recycling conduit unit 101 may be mixed with other components or agents, such as an oxidizing agent or a combustion product. In particular, the monoatomic gas in the gas-recycling conduit unit 101 may be mixed with other components or agents in sections or parts of the gas-recycling conduit unit 101, such as a section of the gas-recycling conduit unit 101 before the internal combustion engine 103, after the internal combustion engine 103 or before / after the separating unit 105.

[0034] According to some embodiments, the designation of directions, such as before or after may be understood, or complemented by the designation “upstream” or “downstream.” Typically, the arrows of the gas-recycling conduit unit 101 may show the direction of the gas circulation. In Figure 1, the monoatomic gas 130 circulating in the gas-recycling conduit unit 101 is also indicated by arrows.

[0035] In particular, the arrows of the gas-recycling conduit unit 101 in Figure 1 show the direction of circulation of the monoatomic gas in the gas-recycling conduit unit 101. The terms “upstream” and “downstream” are typically understood with respect of the direction of circulation of the monoatomic gas. For instance, the gas mixer unit 102 is shown upstream of the internal combustion engine 103. The separating unit 105 may be understood as being located downstream of the internal combustion engine 103.

[0036] According to embodiments described herein, the gas-recycling conduit unit 101 is a gasrecycling conduit unit for the monoatomic gas 130. Typically, the gas-recycling conduit system 101 extends from the exhaust outlet 122 to the inlet 121 for transporting the monoatomic gas 130 from the exhaust outlet back to the inlet thereby forming a loop for the monoatomic gas 130.

[0037] Typically, the gas-recycling conduit unit 101 may be understood as a conduit unit, in which the monoatomic gas runs or circulates. According to some embodiments, the gas-recycling conduit unit 101 may be understood as a conduit unit, in which the monoatomic gas substantially runs in a kind of cycle. In particular, the gas-recycling conduit unit 101 allows the monoatomic gas to be used in more than one cycle of a combustion process. By (especially continuously) circulating in the gas-recycling conduit unit 101 , the monoatomic gas is used for the combustion process every time it passes the internal combustion engine 103. The gas-recycling conduit unit 101 may be described as enabling a re-cycling of the monoatomic gas, which has already passed the internal combustion engine.

[0038] According to some embodiments, the gas-recycling conduit unit 101 may substantially be a closed loop. In the closed loop, the monoatomic gas may circulate for being re-used cycle by cycle. Typically, the substantially closed loops may show some (small, or even neglectable) leaks or positions being permeable for a small amount of monoatomic gas. On the other hand, the gas-recycling conduit unit 101 may provide a source, or may be connectable to a source, or may be connected to a source of monoatomic gas, especially to balance the loss of monoatomic gas due to leaks or permeable positions in the gas-recycling conduit unit 101. In the Figures, the source of monoatomic gas is shown as source 135.

[0039] According to some embodiments described herein, a separating unit 105 is provided in the gasrecycling conduit unit 101 of the monoatomic-gas power cycle arrangement 100. Typically, the separating unit is adapted for separating the monoatomic gas 130 from the combustion product, which typically exits the outlet 122 of the internal combustion engine 103 as a mixture denoted as exhaust product 133. The exhaust product 133 is exemplarily shown as arrow in the gasrecycling conduit unit in the Figures. According to embodiments described herein, the separating unit 105 is adapted for removing partially or completely the combustion product from the gas-recycling conduit system 101, or separate partially or completely the combustion product from the monoatomic gas. According to some embodiments described herein the separating unit 105 provides a separating outlet 134 for the combustion product, which has been separated from the monoatomic gas. In particular, the combustion product is removed from the monoatomic gas power cycle arrangement and, especially, the gas-recycling conduit unit. The monoatomic gas typically continuous to circulate in the gas-recycling conduit unit 101 downstream of the separating unit 105.

[0040] According to some embodiments, the separating unit 105 may be, or may include a condenser unit. For instance, the combustion product may be condensed and, in particular, removed from gas-recycling conduit unit 101. In some embodiments, the condenser unit may use temperature differences for condensing the combustion product, but keep the monoatomic gas. For instance, if the fuel in the internal combustion engine was H2;the combustion product may be H2O. The H2O is guided together with the monoatomic gas from the internal combustion engine 103 to the separating unit 105. In the separating unit, the H2O is condensed and led off the gasrecycling conduit unit 101 through the separating outlet 134. In some embodiments, the separating unit 105 is adapted for separating H2O and / or CO2from the monoatomic gas.

[0041] According to embodiments described herein, the monoatomic-gas power cycle arrangement 100 includes a turbomachine unit 110. Typically, the turbomachine unit includes a turbine 111 and a compressor 112. In the embodiment of Figure 1, the turbine 111 and the compressor 112 are exemplarily connected to each other via a shaft. According to embodiments described herein, the turbomachine unit 110 is connected to the internal combustion machine 103. The turbine 111 of the turbomachine unit 110 is arranged to be driven by the exhaust product 133 of the internal combustion engine, and, especially is arranged upstream of the separating unit 105. The compressor of the turbomachine unit 110 is arranged for compressing the monoatomic gas 130 downstream of the separating unit 105, eventually mixed with the oxidizing agent and / or fuel (depending e.g. on the position of the mixer unit 102, which may be positioned upstream of the compressor according to some embodiments described herein, and / or on the position at which the fuel is provided).

[0042] According to some embodiments described herein, the addition of a turbomachine unit may further improve the thermal efficiency of the process performed by the monoatomic gas power cycle arrangement. Typically, a monoatomic gas power cycle arrangement has the effect to achieve a higher thermal efficiency compared to known arrangements of internal combustion engines. Typically, when the monoatomic gas power cycle arrangement is used with respective fuels, the advantage of a higher thermal efficiency comes with almost zero emissions, in particular CO2and / or NOXemissions. For instance, when the working fluid acting as a diluent is a monoatomic gas (such as, for instance, Argon) instead of Nitrogen in known arrangements, the result is a higher specific heat ratio and the absence of NOXproduction (especially as long as NH3is not the fuel). Unlike in the case of conventional engines operated with air, no compromise between efficiency and NOXemissions has to be done in a monoatomic gas power cycle arrangement according to some embodiments described herein. The engine according to some embodiments described herein can be set on its best efficiency operating mode (such as fuel consumption optimized), without any drawback on the emissions side. This is an additional advantage for thermal efficiency offered by the engine according to some embodiments described herein.

[0043] Typically, the turbomachine unit 110 is adapted to control (and / or influence) pressure and temperature of the exhaust product 133 in the gas-recycling conduit system 101 downstream of the turbine 111, especially by the turbine acting on the exhaust product coming from the outlet of the internal combustion engine. The turbomachine unit 110 is adapted to especially control (and / or influence) temperature and pressure in the separating unit 105, downstream of the turbine 111. In some embodiments, the turbomachine unit 110 includes a control arrangement for controlling temperature and pressure downstream of the turbine of the turbomachine unit, as will be explained in detail below.

[0044] In some embodiments, the turbomachine unit is able to actively control (and / or influence) the temperature and pressure of the exhaust product before and in the separating unit 105. For instance, the kind of turbomachine used in the turbomachine unit, the operation parameters of the turbomachine unit, the size of the turbomachine unit, the control of the single components of the turbomachine unit, the components of the turbomachine unit and the like may contribute to an active control of pressure and temperature of the exhaust product.

[0045] Typically, the pressure level upstream of the separating unit plays a role in controlling the dew point in the separating unit, and in aligning it with the operational requirements of the separating unit. According to some embodiments, which may be combined with other embodiments described herein, controlling the absolute pressure and temperature level before the separating unit affects not only the dew point in the separating unit, but may also affect the CO2capture in a C02capture unit. A C02capture unit may be provided in the monoatomic gas power cycle arrangement either as a separate unit, or as a part of the separating unit shown in the Figures.

[0046] According to some embodiments, which may be combined with other embodiments described herein, a cooler arrangement 120 is provided by the monoatomic-gas power cycle arrangement in the gas-recycling conduit unit. Typically, the cooler arrangement 120 may be located downstream of the compressor of the turbomachine unit 110 and, especially, upstream of the internal combustion engine. In other words, the cooler arrangement 120 may be arranged between compressor 112 of the turbomachine unit 110 and internal combustion engine 103. In some embodiments, the cooler arrangement 120 may be denoted as an intercooler. According to some embodiments, which may be combined with other embodiments described herein, the cooler arrangement may be a charge air cooler for cooling the monoatomic gas, the mixture of monoatomic gas and the oxidizing agent 131 (which might be added to the monoatomic gas at a position upstream of the cooler arrangement in some embodiments, as described in detail below), or the mixture of monoatomic gas, the oxidizing agent 131 and the fuel (if the fuel is injected upstream of the cooler arrangement). According to some embodiments, which may be combined with other embodiments described herein, the cooler arrangement may be an air cooler, a water cooler or any other fluid cooler.

[0047] Figure 2 shows a monoatomic-gas power cycle arrangement 100 according to some embodiments described herein. Typically, the internal combustion engine 103, the separating unit 105 and the gas-recycling conduit unit 101 may be the same or similar as the corresponding elements described with respect to Figure 1.

[0048] In Figure 2, the turbomachine unit 110 includes a wastegate 114 according to an embodiment. The wastegate 114 allows for instance to separate an amount of exhaust gas downstream of the internal combustion engine 105 and upstream of the turbine 111 of the turbomachine unit 110. A wastegate may be used to limit the amount of exhaust gases that enters the turbine of the turbomachine unit. The separated part of the exhaust product is guided to circumvent the turbine 111 of the turbomachine unit 110 and is, especially, added to the exhaust product in the gasrecycling conduit unit 101 again downstream of the turbine 111 of the turbomachine unit 110. According to some embodiments described herein, the wastegate for the turbomachine unit 110 (including especially a controllable valve) allows for controlling the amount of exhaust product driving the turbine 111. Consequently, pressure and temperature of the exhaust product can even better be controlled before (or upstream) of the separating unit. According to some embodiments, the wastegate may also be denoted as a bypass. In some embodiments, which may be combined with other embodiments described herein, the turbomachine unit 110 and the gas-recycling conduit unit 101 may include a compressor bypass for limiting the gas passing through the compressor. Bypassing the compressor may be an alternative, or additional way to increase the control of the properties of the exhaust product upstream of the separating unit 105.

[0049] In some embodiments, which may be combined with other embodiments described herein, the monoatomic gas power cycle arrangement 100 as described herein includes an engine by-pass. Typically, an engine bypass may be used for controlling the amount of gas entering the internal combustion engine, or, especially, the amount of gas downstream of the compressor of the turbomachine unit 110 entering the internal combustion engine. The engine bypass may serve as a method to decouple the compressor gas flow from the engine gas flow. Specifically, when the bypass is opened at a certain turbocharger (TC) speed and compressor flow, it results in a reduction in intake receiver pressure. Consequently, the decrease in pressure affects the engine gas flow. The bypass plays a role in controlling and managing the flow dynamics within the system, allowing for adjustments in the engine's gas flow under specific conditions according to some embodiments described herein.

[0050] Figure 3 shows a monoatomic-gas power cycle arrangement 100 according to some embodiments described herein. Typically, the internal combustion engine 103, the separating unit 105 and the gas-recycling conduit unit 101 may be the same or similar as the corresponding elements described with respect to Figure 1 or Figure 2.

[0051] According to some embodiments, Figure 3 includes a turbine 111 with a variable turbine geometry 113. The turbine 111 of the embodiment of Figure 3 may include adaptable vanes to especially alter the effective flow area of the turbine. By adapting the vanes of the turbine 111, the rotation speed and the power of the turbomachine unit may be controlled. This allows in turn an active, and especially situational, control of the temperature and pressure of the exhaust product upstream of the separating unit 105.

[0052] In some embodiments, which may be combined with other embodiments described herein, the turbomachine unit as described herein is provided with a variable compressor geometry. With a variable compressor geometry, the operational parameter of the turbomachine unit can be controlled. Consequently, the temperature and pressure of the exhaust product led out of the turbomachine unit can be controlled upstream of the separating unit 105.

[0053] Typically, the wastegate, the variable turbine geometry and / or the variable compressor geometry may be controlled with a pneumatic and / or electric actuator. For instance, the wastegate valve may be controlled with a pneumatic and / or electric actuator according to the operational range and efficiency of the separating unit. In another example, the position of the vanes of the turbine may be controlled by a pneumatic and / or electric actuator according to the operational range and efficiency of the separating unit.

[0054] Figure 4 shows a monoatomic gas power cycle arrangement 100 according to some embodiments described herein. Typically, the internal combustion engine 103, the separating unit 105 and the gas-recycling conduit unit 101 may be the same or similar as the corresponding elements described with respect to Figure 1, 2, or 3. The embodiment shown in Figure 4 includes a turbomachine unit, and especially an electrically assisted turbomachine unit 115. According to some embodiments, the electrically assisted turbomachine unit may be equipped with one or two electric machines 116. In the embodiment of Figure 4, one electric machine 116 (such as an electric motor or generator) is shown, especially connected to the turbomachine unit. Typically, one or both of the turbine of the turbomachine unit and the compressor of the turbomachine unit may be connected to one common electric machine 116 or two separate electric machines (as shown below with respect to Figure 5), especially to control independently the operation of the respective component(s) of the turbomachine unit.

[0055] Generally, the turbomachine unit according to embodiments described herein may be provided with a shaft between the compressor and the turbine. In particular, the turbomachine unit according to embodiments described herein may include one electric machine connected to either of the turbine or the compressor and a shaft between the turbine and the compressor.

[0056] Figure 5 monoatomic gas power cycle arrangement 100 according to some embodiments described herein. Typically, the internal combustion engine 103, the separating unit 105 and the gas-recycling conduit unit 101 may be the same or similar as the corresponding elements described with respect to Figure 1, 2, 3, or 4. As can be seen in the embodiment of Figure 5, the turbomachine unit according to some embodiments described herein, may have no (especially direct) mechanical connection between the turbine 111 and the compressor 112, such as a shaft. In some embodiments, the turbomachine unit without shaft between the turbine and the compressor may be provided with two electric machines 116.

[0057] Typically, one of the two electric machines 116 may be adapted for being connected and, especially, for controlling the turbine 111 and the other one of the two electric machines may be adapted for being connected and, especially, for controlling the compressor 112.

[0058] Having one or two electric machines for the turbomachine unit may generally be used for an independent control of the turbine and the compressor. The operational range of the turbomachine unit can be extended by an independent control of the turbine and the compressor. For instance, different speeds of the turbine and the compressor of the turbomachine unit may be realized with an independent control of the turbine and the compressor.

[0059] According to some embodiments described herein, which may be combined with other embodiments described herein, the electric machine(s) may be used for control, but may also be used for extracting energy from the turbomachine unit. Typically, the extraction of electric power from the turbomachine unit (especially by one or two electric machines) may further improve the efficiency of the whole monoatomic gas power cycle arrangement according to embodiments described herein. According to some embodiments described herein, which may be combined with other embodiments described herein, the electric machine(s) may be used for control, but may also be used for bringing energy to the turbomachine unit. Typically, the inj ection of electric power to the turbomachine unit (especially by one or two electric machines) may further improve the flexibility of the whole monoatomic gas power cycle arrangement according to embodiments described herein, for example when the turbine power is not sufficient to drive the compressor.

[0060] In some embodiments, which may be combined with other embodiments described herein, the turbomachine unit in a monoatomic gas power cycle arrangement according to embodiments described herein includes multi-entry turbine(s) and / or multiple turbocharging units, especially arranged in series and / or in parallel with or without the possibility to close, at least partially, at least one turbine entry.

[0061] According to some embodiments described herein, the additional features of the turbomachine unit as described herein, such as wastegate, variable turbine geometry, variable compressor geometry, electrically assisted turbomachine, compressor by-pass, engine by-pass, and the like may be denoted as a control arrangement for controlling the pressure and temperature of the exhaust product.

[0062] In the monoatomic gas power cycle arrangement according to embodiments described herein, the dew point within the separating unit and the temperature and the pressure upstream of the separating unit are typically controlled from a different position in the monoatomic gas power cycle arrangement, especially at (upstream and downstream of, especially immediately upstream and downstream of) the internal combustion engine. For obtaining the control of the parameter in the separating unit, and especially for influencing the efficiency of the separating unit, the setup of the thermal conditions at elements different to the separating unit is influenced, in particular by the turbomachine unit.

[0063] As can be seen in the Figures 1 to 5, the monoatomic gas power cycle arrangement according to some embodiments is exemplarily shown with a cooler arrangement 120 downstream of the compressor 112 of the turbomachine unit and a gas mixer unit 102 for mixing an oxidizing agent 131 (such as oxygen) to the monoatomic gas circulating in the gas-recycling conduit unit. According to some embodiments, which may be combined with other embodiments described herein, the gas mixer unit 102 may be placed at any position upstream of the internal combustion engine 103. For instance, the gas mixer unit 102 may be placed as shown in the Figures 1 to 5 downstream of the compressor 112 of the turbomachine unit, and in particular between the cooler arrangement 120 and the internal combustion engine 103. Alternatively, the gas mixer unit 102 may be placed between the compressor 112 of the turbomachine unit 110 and the cooler arrangement 120 in some embodiments. According to some embodiments, the gas mixer unit 102 may be placed upstream of the compressor 112 of the turbomachine unit 110.

[0064] According to some embodiments, the monoatomic gas referred to herein may be understood as a gas containing monoatomic molecules. In some embodiments, the monoatomic gas may substantially completely be composed of monoatomic molecules, may be composed as a mixture of more than one kind of monoatomic molecules (such as, for instance, a mixture of Ar and He), or may be composed as a mixture of monoatomic molecules and non-monoatomic molecules. In the case of a substantially complete monoatomic molecule gas, substantially all the gas molecules may be individual atoms of a single element, such as for instance helium (He) or argon (Ar). Alternatively, in the case of a gas mixture, the gas may contain one or several kind(s) of monoatomic molecules and any kind of diatomic and / or any kind of polyatomic molecules. However, in the case the monoatomic gas as referred to herein is composed of monoatomic molecules and a portion of diatomic or polyatomic molecules, the portion of diatomic or polyatomic molecules may typically be less than 20%, more typically less than 10%, and even more typically less than 5% by volume concentration.

[0065] A property being denoted with “substantially” herein may be understood as the property including small or minor deviations. For instance, a gas substantially completely consisting of monoatomic molecules may be understood as a gas consisting of typically more than about 97% of monoatomic molecules, more typically more than about 98% of monoatomic molecules, and even more typically more than about 99% of monoatomic molecules. In another example, a substantially closed loop may be understood as a closed loop having minor and / or neglectable leaks regarding the volume of the loop. For instance, a leak in a substantially closed loop may result in a loss of typically less than about 15%, more typically less than about 10%, and even more typically less than about 5% of the gas volume circulating in the loop (especially for each circulation).

[0066] According to some embodiments described herein, which may be combined with other embodiments described herein, the monoatomic gas may contain Argon. Generally, Argon is a noble gas and can be found in the ambient air with a concentration of about 1% in volume, making it cost affordable for extraction.

[0067] Figure 6 shows a flowchart of a method 200 for providing a monoatomic-gas power cycle arrangement 100 according to embodiments described herein. Typically, the monoatomic-gas power cycle arrangement provided by the method 200 may be a monoatomic-gas power cycle arrangement 100 as exemplarily described above, in particular with respect to Figures 1 to 5. Typically, the monoatomic-gas power cycle arrangement 100 is adapted for combusting a fuel in a mixture with a monoatomic gas 130 in an internal combustion engine 103 having an inlet 121 for receiving the monoatomic gas 130, in particular mixed with the fuel and / or other input gases like an oxidizing agent. According to some embodiments, the inlet 121 may be adapted and / or placed to pass the monoatomic gas (or the gas mixture) into the combustion chamber of the internal combustion engine of the monoatomic-gas power cycle arrangement. Typically, the internal combustion engine may include an exhaust outlet 122 for letting out the monoatomic gas mixed with a combustion product resulting from the combustion in the combustion chamber. In particular, the monoatomic gas mixed with a combustion product resulting from the combustion in the combustion chamber may be denoted as an exhaust product.

[0068] The method 200 typically includes in block 201 providing a gas-recycling conduit system 101 for the monoatomic gas 130. According to some embodiments, the gas-recycling conduit system 101 may be adapted for circulating the monoatomic gas within the gas-recycling conduit system 101. Especially, providing the gas-recycling conduit system 101 may include guiding or installing a conduit system from the exhaust outlet (122) of the internal combustion engine to the inlet 121 of the internal combustion engine. Typically, the gas-recycling conduit system 101 is installed in a way allowing for transporting the monoatomic gas (130) from the exhaust outlet back to the inlet. According to some embodiments, the gas-recycling conduit system 101 extending from the outlet 122 to the inlet 121 of the internal combustion engine may form a kind of a loop, especially a substantially closed loop for the monoatomic gas 130.

[0069] In some embodiments, which may be combined with other embodiments described herein, the gas-recycling conduit unit 101 may be equipped with a kind of drive, such as a pump, for reliably ensuring the (especially constant) circulation of the monoatomic gas.

[0070] In step 202, the gas-recycling conduit system 101 is guided to pass through the separating unit 105, which is adapted for separating partially or completely the monoatomic gas from a combustion product coming from the combustion in the internal combustion engine 103. Typically, the separating unit 105 may be a condenser, especially for separating H2O or and / or CO2from the monoatomic gas circulating in the gas-recycling conduit system 101.

[0071] According to embodiments described herein, the method 200 includes in block 203 equipping 202 the gas-recycling conduit system 101 with a turbomachine unit 110 for the internal combustion engine. The method may further include connecting the turbomachine unit 110 to the internal combustion engine. Typically, the turbomachine unit 110 may include a turbine 111 arranged to be driven by the exhaust product 133 upstream of the separating unit 105, and may include a compressor 112 arranged for compressing the monoatomic gas 130 (eventually mixed with an oxidizing agent and / or fuel, depending e.g. on the position of the gas mixer unit 102) downstream of the separating unit 105, and, especially upstream of the internal combustion engine.

[0072] Generally, the turbomachine unit used in the method 200 according to some embodiments may be a turbomachine unit as described above, and, in particular, a turbomachine unit as described with respect to Figures 1 to 5. According to embodiments described herein, the turbomachine unit used in the method 200 may include a wastegate 114, a compressor by-pass, an engine bypass, multi-entry turbine(s), a variable turbine geometry 113, a variable compressor geometry, multiple turbocharging units, and / or an electrically assisted turbomachine unit 115, as especially described in detail above.

[0073] Using a turbomachine unit in the monoatomic gas power cycle arrangement according to embodiments described herein not only increases the thermal efficiency of the system but also allows for a control of the temperature and pressure of the exhaust product upstream of the separating unit. Typically, the temperature and the pressure upstream of the separating unit influences the dew point in the separating unit, which is in particular useful for an effective operation of the separation unit.

[0074] According to some embodiments described herein, the method for providing a monoatomic gas power cycle arrangement may (consequently) include controlling pressure and temperature of the exhaust product 133 in the gas-recycling conduit system, especially downstream of the turbine 111 of the turbomachine unit, such as for instance in the separating unit 105. Typically, the turbomachine unit 110 may be adapted for controlling the pressure and temperature of the exhaust product. In particular, the method according to some embodiments described herein may include actively controlling temperature and pressure of the exhaust product in the gasrecycling conduit unit 101 downstream of the turbine 111 of the turbomachine unit 110. For instance, the active control of temperature and pressure of the exhaust product in the gasrecycling conduit unit 101 may be performed by properties and equipment of the turbomachine unit, e.g. a wastegate, a variable turbine geometry, an electrified turbomachine unit and the like.

[0075] In some embodiments, which may be combined with other embodiments described herein, the method includes arranging a gas mixer unit 102 for mixing an oxidizing agent with the monoatomic gas, especially upstream of the internal combustion engine, e.g. between the compressor of the turbomachine unit and the internal combustion engine. In some embodiments, a cooler arrangement is provided downstream of the compressor. In particular, the gas mixer unit may be arranged between the compressor and the cooler arrangement, between the cooler arrangement and the internal combustion engine, or upstream of the compressor according to some embodiments of the herein described method. According to some embodiments, which may be combined with other embodiments described herein, the monoatomic gas power cycle arrangement once arranged leads the monoatomic gas 130 generally through the gas-recycling conduit system 101. Typically, the monoatomic gas 130 circulates in the gas-recycling conduit system 101. Starting exemplarily after or downstream of the separating unit 105, the monoatomic gas 130 is led in direction of the arrows as shown in Figures 1 to 5. According to some embodiments, the monoatomic gas 130 is guided to the compressor 112 of the turbomachine unit 110, where the monoatomic gas is compressed. After, or downstream of the compressor, a cooler arrangement 120 may be provided for cooling the compressed monoatomic gas 130. Typically, the monoatomic gas 130 is mixed with an oxidizing agent 131 in a gas mixer unit 102 before entering the internal combustion engine 103, especially via inlet 121. In the internal combustion engine, the monoatomic gas is guided together with the oxidizing agent to the combustion chamber, to which the fuel (examples see above) is added. During the combustion process in the combustion chamber of the internal combustion engine, a combustion product is generated. Typically, the combustion product together with the monoatomic gas is led out of the internal combustion engine via the outlet of the internal combustion engine as exhaust product. The exhaust product then partially or completely passes the turbine of the turbomachine unit. Downstream of the turbine 111 of the turbomachine unit 110, the exhaust product is guided in the gas-recycling conduit system to the separating unit 105, which separates the combustion product from the monoatomic gas, e.g. by a condensation process. The combustion product may be led out of the separating unit 105, and in particular out of the gas-recycling conduit unit by a separating outlet 134. Typically, the monoatomic gas 130 remains in the gas-recycling conduit system and, especially, starts a new cycle downstream of the separating unit.

[0076] According to some embodiments described herein, the monoatomic gas power cycle arrangement and the method for providing a monoatomic gas power cycle arrangement may exemplarily be used in and typically be adapted for power generator applications, marine applications, space program applications, submarine propulsions (in particular useful due to the lacking exhaust bubbles), marine auxiliary applications, heavy duty class applications, high speed applications, medium speed applications, low speed applications, spark ignited internal combustion engines, Diesel engines, CAI (controlled auto ignition) engine, HCCI (homogenous charge compression ignition) engines, zero emissions applications, port fuel injection engines, direct injection engines and the like. This written description uses examples to describe the subject matter herein, including the best mode, and also to enable any person skilled in the art to make and use the subject matter. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims

[0077] Reference numeral list

[0078] 100 Monoatomic-gas power cycle arrangement

[0079] 101 gas-recycling conduit system

[0080] 102 gas mixer unit

[0081] 103 internal combustion engine

[0082] 105 separating unit

[0083] 110 turbomachine unit

[0084] 111 turbine

[0085] 112 compressor

[0086] 113 variable geometry turbine

[0087] 114 wastegate of turbomachine unit

[0088] 115 electrically assisted turbomachine unit

[0089] 116 electric machine

[0090] 120 cooler arrangement

[0091] 121 inlet of internal combustion engine

[0092] 122 outlet of internal combustion engine

[0093] 130 monoatomic gas

[0094] 132 fuel

[0095] 133 exhaust product

[0096] 134 separating outlet

[0097] 135 source of monoatomic gas

[0098] 200 method

[0099] 201-203 block of method

Claims

Claims:

1. Monoatomic-gas power cycle arrangement (100) comprising: an internal combustion engine (103) having a combustion chamber adapted for combusting a fuel (132) in a mixture with a monoatomic gas (130) and having an inlet (121) for receiving the monoatomic gas (130) and an exhaust outlet (122) for letting out an exhaust product (133) comprising the monoatomic gas mixed with a combustion product resulting from the combustion in the combustion chamber; a gas-recycling conduit system (101) for the monoatomic gas (130), the gas-recycling conduit system (101) extending from the exhaust outlet (122) to the inlet (121) for transporting the monoatomic gas (130) from the exhaust outlet (122) back to the inlet (121) thereby forming a loop for the monoatomic gas (130), wherein the gas-recycling conduit system (101) comprises: o a separating unit (105) for separating the monoatomic gas (130) from the combustion product and for removing partially or completely the combustion product from the gas-recycling conduit system (101), and o a turbomachine unit (110) connected to the internal combustion machine (103) with a turbine (111) arranged to be driven by the exhaust product (133) upstream of the separating unit (105), and with a compressor (112) arranged for compressing the monoatomic gas (130) downstream of the separating unit (105) wherein the turbomachine unit (110) comprises at least one of: a) a wastegate (114); b) a compressor by-pass; c) an engine by-pass; d) multi-entry turbine(s); e) a variable turbine geometry (113); f) variable compressor geometry; g) multiple turbocharging units; and,h) an electrically assisted turbomachine unit (115).

2. The monoatomic-gas power cycle arrangement (100) according to claim 1, wherein the turbomachine unit (110) comprises a control arrangement for controlling, especially actively controlling, pressure and temperature of the exhaust product (133) in the gas-recycling conduit system (101) downstream of the turbine (111), especially in the separating unit (105).

3. The monoatomic-gas power cycle arrangement (100) according to any of the preceding claims, further comprising a gas mixer unit (102) for mixing the monoatomic gas with an oxidizing agent (131).

4. The monoatomic-gas power cycle arrangement (100) according to any of the preceding claims, wherein the gas-recycling conduit system (101) forms substantially a closed loop for the monoatomic gas (130).

5. The monoatomic-gas power cycle arrangement (100) according to any of the preceding claims, wherein the monoatomic gas is Argon.

6. The monoatomic-gas power cycle arrangement (100) according to any of the preceding claims, wherein the internal combustion engine (103) is an internal combustion engine for combusting at least one of hydrogen, methane, methanol, ammonia, e-fuels, and a fuel having the general formula CmHnOpNq.

7. The monoatomic-gas power cycle arrangement (100) according to any of the preceding claims, wherein the separating unit (105) is adapted for separating H2O and / or CO2from the monoatomic gas.

8. The monoatomic-gas power cycle arrangement (100) according to any of the preceding claims, wherein the separating unit (105) comprises a condenser unit.

9. The monoatomic-gas power cycle arrangement (100) according to any of the preceding claims, wherein the turbomachine unit (110) comprises a shaft coupling the turbine (111) to the compressor (112) for driving the compressor, and / or at least one electric machine (116) coupled to the compressor (112) for driving the compressor.

10. The monoatomic-gas power cycle arrangement (100) according to any of the preceding claims, further comprising a cooler arrangement (120) located downstream of the compressor (112) of the turbomachine unit (110).

11. Method for providing a monoatomic-gas power cycle arrangement (100) for combusting a fuel in a mixture with a monoatomic gas (130) in an internal combustion engine (103) having an inlet (121) for receiving the monoatomic gas (130) and an exhaust outlet (122) for letting out an exhaust product (133) comprising the monoatomic gas (130) mixed with a combustion product resulting from the combustion in the combustion chamber, the method comprising:Providing (201) a gas-recycling conduit system (101) for the monoatomic gas (130), the gas-recycling conduit system (101) extending from the exhaust outlet (122) to the inlet (121) for transporting the monoatomic gas (130) from the exhaust outlet back to the inlet thereby forming a loop for the monoatomic gas (130);Passing (202) the gas-recycling conduit system (101) for the monoatomic gas through a separating unit (105) for separating partially or completely the monoatomic gas from the combustion product; and,Equipping (203) the gas-recycling conduit system (101) with a turbomachine unit (110) and connecting the turbomachine unit (110) to the internal combustion engine,the turbomachine unit (110) comprising a turbine (111) arranged to be driven by the exhaust product (133) upstream of the separating unit (105), and comprising a compressor (112) arranged for compressing the monoatomic gas, with eventually the fuel (130), downstream of the separating unit (105);- wherein equipping the internal combustion engine (103) with a turbomachine unit (110) comprises equipping the internal combustion engine (103) with at turbocharging unit comprising at least one of: o a wastegate (114); o a compressor by-pass; o an engine by-pass; o multi-entry turbine(s); o a variable turbine geometry (113); o variable compressor geometry; o multiple turbocharging units; and, o an electrically assisted turbomachine unit (115).

12. The method according to claim 11, further comprising controlling, especially actively controlling, pressure and temperature of the exhaust product (133) in the gas-recycling conduit system downstream of the turbine (111), especially in the separating unit (105).

13. The method according to any of claims 11 to 12, further comprising arranging a gas mixer unit (102) for mixing an oxidizing agent (131) with the monoatomic gas (130).

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