Heated catalyst and internal combustion engine provided with same

Abstract

The invention relates to a heated catalyst (2) which is designed to convert fuel using an oxidizing agent, wherein the heated catalyst (2) has a housing (25) which has an inlet (21) and an outlet (22), wherein the inlet (21) is designed to supply the oxidizing agent and the outlet (22) is designed to discharge a product gas, and wherein the heated catalyst (2) also contains a catalyst carrier (5) arranged in the housing (25), wherein a fuel plate (6) is arranged on one side of the catalyst carrier (5) and is designed to supply the fuel to the catalyst carrier (5), and a perforated plate (4) is arranged on a side of the catalyst carrier (5) opposite the fuel plate (6) and is designed to supply the oxidizing agent to the catalyst carrier (5), wherein the fuel plate (6) is provided with a transport device which has a plurality of channels (61) which are introduced into the side of the fuel plate (6) facing the catalyst carrier (5) and are at least partially open towards the catalyst carrier (5).

Description

Description Title of the invention: Heating catalyst and internal combustion engine equipped therewith field of technology

[0001] The invention relates to a heating catalyst for an exhaust aftertreatment device or a reformer, which is configured to react fuel with an oxidizing agent, wherein the heating catalyst has a housing having an inlet and an outlet, wherein the inlet is configured to supply the oxidizing agent and the outlet is configured to discharge a product gas, and wherein the heating catalyst further comprises a catalyst support arranged in the housing, wherein a fuel plate is arranged on one side of the catalyst support, which is configured to supply the fuel to the catalyst support, and a perforated plate is arranged on one side of the catalyst support opposite the fuel plate, which is configured to supply the oxidizing agent to the catalyst support. State of the art

[0002] A heating catalyst is known from WO 2020 / 193595 A1. A partial stream of exhaust gas from an internal combustion engine and / or fresh air is fed to the heating catalyst. Fuel is also supplied to the heating catalyst. The fuel is either completely oxidized at the heating catalyst, producing a hot gas. In other operating conditions, the fuel can be partially converted at the heating catalyst, producing a product gas in the form of a reformate or synthesis gas, which has a lower light-off temperature at an oxidation catalyst compared to the unmodified fuel. The hot gas or the product gas is fed to a component of an exhaust aftertreatment system, for example, a three-way catalyst, an SCR catalyst, an oxidation catalyst, a NOx storage catalyst, or a particulate filter. The heating catalyst enables the exhaust aftertreatment system to operate according to a 31974 PWO To quickly bring the engine up to operating temperature after a cold start. On the other hand, a particulate filter can be regenerated by applying heat, regardless of the engine's operating condition.

[0003] The well-known heating catalyst has the disadvantage that the catalyst carrier and / or the fuel plate can be destroyed by high thermal stress or hotspots under certain operating conditions. Conversely, under lower load conditions, individual areas can cool down, leading to the formation of deposits or coking. Technical task

[0004] Based on the prior art, the invention is therefore based, among other things, on the objective of increasing the operational reliability and service life of a heating catalyst. Technical solution

[0005] According to one aspect of the present description, a heating catalyst is disclosed. In some embodiments, the heating catalyst can be configured and designed to raise the temperature of an exhaust aftertreatment system or to supply thermal energy to an exhaust aftertreatment system. In some embodiments, the exhaust aftertreatment system can be selected from a three-way catalyst, an SCR catalyst, an oxidation catalyst, a NOx storage catalyst, and / or a particulate filter. The exhaust aftertreatment system can contain at least one of the aforementioned elements. In other embodiments, the exhaust aftertreatment system can also contain several of the aforementioned elements. In still other embodiments, elements can be combined; for example, a particulate filter can also serve as an SCR catalyst by means of a suitable coating.

[0006] In other embodiments, the heating catalyst can be configured and designed to raise the temperature of a reformer and supply thermal energy to the reformer. The reformer can be configured and designed to convert chain hydrocarbons into branched hydrocarbons. 31974 PWO to convert hydrocarbons or to produce pure hydrogen from a methanol-water mixture, releasing carbon dioxide.

[0007] In some embodiments, the oxidizing agent supplied to the heating catalyst can be or contain exhaust gas. In other embodiments, the oxidizing agent can be or contain ambient air.

[0008] The exhaust gas from an internal combustion engine can be discharged via an exhaust pipe and fed to the exhaust aftertreatment system. The heating catalyst can have a housing with an inlet and an outlet. The inlet can be connected to an exhaust pipe in such a way that at least a partial flow of the exhaust gas flowing in the exhaust pipe can be fed into the housing through the inlet. Furthermore, the outlet can be connected to an exhaust pipe in such a way that hot gas or product gas generated in the heating catalyst can be discharged from the housing and fed into the exhaust pipe. In some embodiments, the inlet can be connected to the exhaust pipe above the outlet when viewed in the direction of exhaust gas flow.

[0009] The housing of the heating catalyst can contain a catalyst support. The catalyst support can be, for example, a metal, a ceramic, or a sheet metal structure. The catalyst support can be a porous body through which products or reactants can flow. In some embodiments, the catalyst support can be a sheet metal structure or composed of a plurality of sheet metal parts. The catalyst support can be provided with a catalytically active coating, which may, for example, contain platinum and / or rhodium. However, the invention does not teach the use of a specific catalytically active material as a solution principle. In some embodiments, the catalyst support itself can consist of or contain a catalytically active material.

[0010] A fuel plate can be arranged on one side of the catalyst support. The fuel plate is designed and intended to distribute supplied fuel across its surface so that it reaches the catalyst or the 31974 PWO The catalyst support can be supplied with fuel. A perforated plate can be arranged on one side of the catalyst support opposite the fuel plate. The perforated plate is designed and intended to supply the catalyst support with the oxidizing agent supplied via the inlet, for example, exhaust gas and / or ambient air. For this purpose, the perforated plate can have a plurality of through-holes through which the exhaust gas or, optionally, another oxidizing agent can flow to the catalyst support. The gaseous oxidizing agent on the one hand and the fuel on the other are thus supplied to the catalyst support from opposite directions and react there. In some embodiments of the invention, the sides of the catalyst support opposite the fuel plate and the perforated plate can each be the sides with the largest surface area.

[0011] In some embodiments, the heating catalyst can be designed and intended to operate in two states. Either the oxidizer and fuel can be supplied stoichiometrically or superstoichiometrically, resulting in complete or nearly complete oxidation of the fuel. The exothermic oxidation reaction produces a hot gas, consisting primarily of CO2 and H2O in addition to N2, which is released at high temperature through the outlet into the exhaust system. The heat introduced in this way can directly heat the exhaust aftertreatment system, or at least one component thereof.

[0012] In the second operating state, the oxidizer and fuel are fed to the catalyst support at substoichiometric concentrations. The exothermic reaction occurring here is sufficient to vaporize the fuel on the fuel plate and partially react it at the catalyst. This produces a product gas in the form of a reformate or synthesis gas, which typically contains shorter-chain hydrocarbons than the fuel and therefore can have a lower light-off temperature. The product gas can be oxidized at individual components of the exhaust aftertreatment system to generate heat directly in a particulate filter or catalyst. 31974 PWO

[0013] The control or regulation of the first or second operating state is achieved on the one hand by the amount of oxidizer supplied and on the other hand by the amount of fuel supplied. In operating states of the internal combustion engine that do not require additional heating of the exhaust aftertreatment system, the heating catalyst can also be deactivated. This can be achieved by cutting off the fuel supply and / or the exhaust gas supply. Alternatively, in operating states of the internal combustion engine that do not require additional heating of the exhaust aftertreatment system, the heating catalyst can be put into a low-power standby state. This can be achieved by reducing the fuel supply and / or the exhaust gas supply.

[0014] The present disclosure further describes a fuel plate equipped with a transport device and usable as part of a heating catalyst. The transport device can have a plurality of channels which are incorporated into the side of the fuel plate facing the catalyst support. Fuel exiting the fuel line and wetting the fuel plate is distributed across the fuel plate by the channels located within it. For this purpose, the channels can be interconnected. In some embodiments, the channels can form a continuously branching network. This allows the fuel to be distributed evenly across the surface of the fuel plate from one or more outlets. For this purpose, the channels can be at least partially open towards the catalyst support, allowing for fuel vaporization.Depending on the internal combustion engine, the fuel used can be gasoline or diesel, a synthetic fuel, a biogenic fuel, DME or OME, or even an alcohol or liquefied petroleum gas. Even fuel distribution reduces or prevents deposits and coking.

[0015] In some embodiments, the heating catalyst may further include a porous molded body. The molded body may be made of a woven, knitted, nonwoven, or foam material and may be positioned between the catalyst support and the fuel plate. In some embodiments, the molded body may be bonded to the fuel plate. 31974 PWO The component is joined. In some embodiments, the component can be made of a metal or alloy. This allows, in a first step, a coarse distribution of the fuel onto the fuel plate through the channels described above. In a second step, the fuel can be drawn from the channels by the component or the capillary forces acting within it and transported towards the catalyst support. This results in a more uniform distribution of the fuel.

[0016] The present disclosure further describes a heating catalyst which also includes a porous molded body arranged between the catalyst support and the fuel plate. The molded body is provided with a transport device comprising a plurality of channels which are incorporated into the side of the molded body facing the fuel plate and are at least partially open towards the fuel plate. Fuel exiting the fuel line and wetting the fuel plate is distributed through the channels located in the molded body. For this purpose, the channels may be interconnected. In some embodiments, the channels can form a continuously branching network. This allows the fuel to be distributed evenly from one or more outlets over the surface of the molded body or the fuel plate.For this purpose, the channels to the catalyst carrier can be at least partially open, allowing fuel vaporization. Depending on the internal combustion engine, the fuel used can be gasoline or diesel, a synthetic fuel, a biogenic fuel, DME or OME, an alcohol, or a liquid gas. The even distribution of the fuel reduces or prevents deposits and coking. The shaped element can simultaneously serve as the catalyst carrier or as an additional element for fuel distribution.

[0017] In some embodiments, channels or transport devices can be present both in the fuel plate and in the porous molded body.

[0018] In some embodiments, the fuel plate may have at least one bore extending from the side facing away from the catalyst carrier to the side of the fuel plate facing the catalyst carrier. 31974 PWO The bore extends and opens into a first channel. The bore can be designed and intended to be connected to a fuel line from the side of the fuel plate facing away from the catalyst support, so that the fuel flows through the bore into the first channel. The first channel can be designed and intended to distribute the fuel quantity across the width of the fuel plate.

[0019] In some embodiments, the bore can have a cross-section that increases in size from the pipe to its opening in the first channel. In some embodiments, the bore can have a conical cross-section. This can reduce the flow velocity of the incoming fuel, thus preventing overflow.

[0020] In some embodiments, the fuel plate can have a plurality of bores extending from the side of the fuel plate facing away from the catalyst support to the side facing the catalyst support, each opening into a first channel or each opening into a first channel facing the corresponding bore. By having a plurality of fuel inlets, power control in some embodiments can be achieved over a wider range and / or with greater accuracy by supplying fuel either through only one or through several bores, so that accordingly only a portion of the fuel plate or the entire fuel plate is wetted with fuel. In some embodiments, the number of bores can be between 1 and approximately 6 or between approximately 2 and approximately 4.

[0021] In some embodiments, the cross-sectional area of ​​the channels can decrease along their length. The channel's cross-sectional area can thus be larger near the bore through which the fuel enters, and smaller at greater distances from the bore. This is because, firstly, fuel evaporates during transport through the channels, thereby reducing the amount transported. Secondly, it is also because the channels branch along their length, so that at greater distances from the bore... 31974 PWO Several channels are available for fuel transport, each carrying a smaller quantity than upstream channels.

[0022] In some embodiments, the fuel can be transported through the channels by gravity. In this case, the installation position of the heating catalyst is chosen such that the fuel plate is inclined relative to the vertical. In some embodiments, the fuel plate can be approximately vertical, i.e., it assumes an angle of inclination of approximately 80° to 100° or 85° to 95° with the horizontal. This ensures the simple transport of the fuel through the channels of the fuel plate.

[0023] In some embodiments, the fuel can be transported through the channels by capillary action. For this purpose, the channels have a cross-section tailored to the respective fuel quantity, allowing the corresponding capillary forces to develop. This ensures fuel transport regardless of the installation position.

[0024] In some embodiments, the cross-sectional area of ​​the channels can be designed along their length such that the fuel propagation speed in the horizontal direction is greater than the fuel propagation speed in the vertical direction. This ensures that the full width of the fuel plate is utilized at all output power levels of the heating catalyst and that power control is managed via the vertical propagation. This can further reduce coking or deposits.

[0025] In some embodiments, the width of the channels can decrease along their length. This reduces the cross-sectional area of ​​the channels along their length, as described above.

[0026] In some embodiments, the depth of the channels can decrease along their length. This embodiment also serves to reduce the cross-sectional area of ​​the channels along their length. In this case, manufacturing can be carried out with a single milling cutter while maintaining a constant channel width. This cutter penetrates less deeply into the material as the channel length increases, thus simplifying the manufacturing process. 31974 PWO

[0027] In some embodiments, the channel width can decrease from approximately 5 mm to approximately 0.5 mm along its length. In other embodiments, the channel width can decrease from approximately 3 mm to approximately 0.8 mm along its length. This cross-sectional area is sufficient to cover a thermal power range of approximately 5 kW to approximately 50 kW in a compact design. Furthermore, the heating catalyst can optionally be operated in a standby state, in which the thermal power is between approximately 50 W and approximately 1 kW, without significant deposits or coking forming.

[0028] In some embodiments, the depth of the channels can decrease along their length from approximately 1 mm to approximately 0.05 mm. In other embodiments, the depth of the channels can decrease along their length from approximately 0.7 mm to approximately 0.1 mm. This allows for simple manufacturing by milling or primary forming, or by forming processes such as embossing.

[0029] In some embodiments, the first channel can be inclined at approximately 20° to 30° to the horizontal when the heating catalyst is installed. This allows for reliable fuel transport by gravity. At the same time, the fuel flows slowly enough to ensure uniform wetting of the fuel plate without dry spots or liquid accumulation, thus preventing coking and hotspots and enabling reliable operation.

[0030] In some embodiments, the fuel plate may have a partial surface without channels. This partial surface may be a circular segment located at the lower boundary edge of the fuel plate when viewed in its installed position. The circular sector may have a height of approximately 10% to approximately 40% or approximately 15% to approximately 35% of the radius of the fuel plate.

[0031] In some embodiments, a plurality of second channels can branch off from the first channel, which, in the installed position of the heating catalyst, are inclined at approximately 40° to approximately 90° to the horizontal. This results in a rapid 31974 PWO Branching of the channels across the surface of the fuel plate is ensured, resulting in uniform wetting.

[0032] In some embodiments, the total length of the channels is selected such that the amount of fuel supplied during partial load operation is completely vaporized before reaching the end of the channels. In such an operating condition, only a portion of the catalyst support or a partial area of ​​the fuel plate is wetted by the fuel vapor or liquid fuel. This allows the temperature in the portion wetted by the fuel vapor to be kept high enough to prevent coking. Under higher power demand, an increasingly larger amount of fuel can then be supplied, wetting an increasingly larger portion of the fuel plate, until at full load the channels or the entire fuel plate are completely wetted.

[0033] In some embodiments, the second channels can have a plurality of first and second longitudinal sections and a plurality of branching points, wherein the first and second longitudinal sections initially diverge and then converge between adjacent branching points. This allows the length of the second channels from their source at the first channel to the outlet at the end of the fuel plate to be increased, thus increasing the flow time. This ensures that the fuel evaporates completely and does not collect in liquid form at the bottom edge of the fuel plate, where it could lead to coking and contamination. In some embodiments, the entire fuel plate can be wetted.

[0034] In some embodiments, adjacent first and second longitudinal sections can form an angle of approximately 70° to approximately 110° with each other. In other embodiments, adjacent first and second longitudinal sections can form an angle of approximately 80° to approximately 100° with each other. In still other embodiments, adjacent first and second longitudinal sections can form an angle of approximately 85° to approximately 95°. Between two adjacent branching points, the second channels thus run approximately in the shape of a rectangle, a square, or a rhombus. At the branching points, backflow can occur. 31974 PWO liquid fuel is coming, so the flow rate through the channels is further reduced to allow enough time for the fuel to evaporate.

[0035] In some embodiments, the transport device or the channels on the fuel plate can be designed such that, at all operating points, a horizontal component of the propagation velocity vn of the fuel metered onto the fuel plate is greater than a vertical component of the propagation velocity VL2 of the fuel metered onto the fuel plate. The propagation velocities are measured using diesel fuel at room temperature, with the wetting behavior of the fuel plate being optically recorded by a camera.

[0036] In some embodiments, the ratio of the horizontal component of the propagation velocity vn of the fuel metered onto the fuel plate to the vertical component of the propagation velocity VL2 of the fuel metered onto the fuel plate can be between approximately 1.05 and approximately 6.5 or between approximately 1.1 and approximately 5.5. In some embodiments, the ratio of the horizontal component of the propagation velocity vn of the fuel metered onto the fuel plate to the vertical component of the propagation velocity VL2 of the fuel metered onto the fuel plate against the power of the heating catalyst can follow a logarithmic curve. This allows the utilization of the reaction area to be optimized, so that the fuel plate requires only one bore 63. This can simplify the control of the heating catalyst.

[0037] The present disclosure further describes a perforated plate having a plurality of through-holes and suitable for use as part of a heating catalyst. The perforated plate can have a plurality of through-holes, which in a first zone of the plate have a smaller number and / or lower areal density and / or smaller diameter. Furthermore, the perforated plate can have at least a second zone in which the perforated plate has a larger number and / or higher areal density and / or larger diameter of through-holes. 31974 PWO Area density is defined as the number of through-holes per unit area. In some embodiments, the second zone can have a larger area than the first zone.

[0038] The stoichiometry of the reaction occurring in the catalyst support can be influenced by the number, diameter, and / or area density of the through-holes in the perforated plate. For example, in one area of ​​the fuel plate opposite the first zone of the perforated plate, the fuel can be vaporized substoichiometrically, while in another area of ​​the catalyst support opposite the second zone, it can be oxidized superstoichiometrically. This can prevent or at least reduce overheating and / or scaling or coking of the fuel plate and / or the catalyst support.

[0039] If the perforated plate has a first and a second zone in which the number and / or diameter and / or area density of the through-holes differ, the first zone can be positioned above the second zone when the heating catalyst is installed. This allows the fuel to initially vaporize substoichiometrically without overheating the catalyst support. A larger quantity of oxidizer can then be added to the second zone, enabling complete fuel conversion.

[0040] In some embodiments, the perforated plate can have a third zone in which the through-holes are designed to generate a purge flow in the fuel-free edge area. This avoids dead zones in the catalyst carrier or on the fuel plate.

[0041] In some embodiments, the through-holes can be arranged in rows that run approximately horizontally when the heating catalyst is installed. In other embodiments, the through-holes can be arranged in rows that run at an angle of approximately 0° to approximately 15° or approximately 0° to approximately 8° to the horizontal when the heating catalyst is installed.

[0042] In some embodiments, the through holes of one row can be offset from the through holes of an adjacent row. 31974 PWO In some embodiments, the offset can be maximized, meaning that the through-holes of one row are located above the spaces between the through-holes of an adjacent row. This feature has the effect of enabling maximum backflow over the catalyst support and good mixing of the product gas.

[0043] In some embodiments, the perforated plate may have a fourth zone in which there are no through-holes. In some embodiments, when the heating catalyst is installed, the fourth zone may be located below the second zone.

[0044] In some embodiments, the diameter of the through-holes can range from approximately 2.0 mm to approximately 2.6 mm. In other embodiments, the diameter of the through-holes can range from approximately 2.3 mm to approximately 4 mm. In still other embodiments, the diameter of the through-holes can range from approximately 2.6 mm to approximately 3.7 mm. This allows the stoichiometry to be varied in different areas of the catalyst support.

[0045] In some embodiments, the perforated plate can be designed such that a proportion of between approximately 1% and approximately 40% or a proportion of between approximately 5% and approximately 27% of the mass flow rate of the oxidizing agent flows through the through-holes of the first zone. In some embodiments, the perforated plate can be designed such that a proportion of between approximately 50% and approximately 97% or a proportion of between approximately 60% and approximately 94% of the mass flow rate of the oxidizing agent flows through the through-holes of the second zone. In some embodiments, the perforated plate can be designed such that a proportion of between approximately 0% and approximately 20% or a proportion of between approximately 2% and approximately 15% of the mass flow rate of the oxidizing agent flows through the through-holes of the third zone.In some embodiments, the perforated plate can be designed such that a proportion of between approximately 0% and approximately 2% or a proportion of between approximately 0% and approximately 1% of the mass flow of the oxidizing agent passes through the fourth zone of the perforated plate. This means that the fourth zone preferably has no through-holes, so that, except for unavoidable leakage, no oxidizing agent is introduced into the fourth zone. 31974 PWO

[0046] In some embodiments, the heating catalyst can be equipped with the fuel plate described and a conventional perforated plate known per se. In other embodiments, the heating catalyst can be equipped with the perforated plate described here and a conventional fuel plate known per se. In still other embodiments, the heating catalyst can have both the perforated plate and the fuel plate described here. In this way, the heating catalyst can be adapted in a variety of ways to the intended use, the exhaust aftertreatment system, and the internal combustion engine.

[0047] In some embodiments, this relates to an internal combustion engine with at least one heating catalyst. In some embodiments, this relates to a motor vehicle or a ship with an internal combustion engine and at least one heating catalyst. A motor vehicle within the meaning of this description can be a passenger car or a truck for use on paved roads. Furthermore, a motor vehicle within the meaning of this description can also be construction machinery, for example, a dump truck, a wheel loader, an excavator, a crane, or any other construction machinery known per se. Brief description of the drawings

[0048] The invention will be explained in more detail below with reference to figures, without limiting the general concept of the invention. Fig. 1

[0049] [fig.1 ] shows a schematic representation of the integration of a heating catalyst into an exhaust pipe. Fig. 2

[0050] [fig.2] shows a fuel plate in view. Fig. 3

[0051] [fig.3] shows a section of Figure 2 on a larger scale. Fig. 4 31974 PWO

[0052] [fig.4] shows a section through a possible embodiment of a fuel inlet. Fig. 5

[0053] [fig.5] shows the ratio of the horizontal and vertical propagation speed of the fuel on the fuel plate against the power output. Description of the embodiments

[0054] Figure 1 illustrates the integration of a heating catalyst 2 into an exhaust pipe 3. Figure 1 shows a longitudinal section through a short part of the exhaust pipe 3 with the heating catalyst 2 attached to it.

[0055] The heating catalyst is designed and intended for use with an internal combustion engine (not shown). The internal combustion engine can be, for example, a diesel engine or a gasoline engine. The internal combustion engine generates an exhaust gas flow 35, which is discharged in the exhaust pipe 3.

[0056] An exhaust flap 7 is located in the exhaust pipe 3, the rotation angle of which can be influenced within the exhaust pipe 3 by means of an actuator 70. The exhaust flap 7 generates exhaust back pressure, thus causing upstream dynamic pressure and downstream negative pressure. The exhaust flap 7 is installed between the inlet 21 and the outlet 22 of the heating catalyst 2. In other embodiments, a pressure difference between the inlet 21 and the outlet 22 can also be generated by a device other than an exhaust flap 7, for example, the turbine of a turbocharger.

[0057] The heating catalyst 2 has a housing 25, which has an inlet 21 and an outlet 22. By partially closing the exhaust flap 7, an overpressure is generated at the inlet 21, which causes a partial flow 351 of the total exhaust gas flow 35 to enter the housing 25 of the heating catalyst 2 through the inlet 21. Thus, the position of the exhaust flap 7 allows the partial flow 351 of the exhaust gas to pass through the housing 25 of the heating catalyst 2. 31974 PWO The partial flow passes through the housing 25 of the heating catalyst 2 and is partially or completely converted. The products exit the housing 25 via the outlet 22 downstream of the inlet 21. The product 352 can contain a hot gas, a reformate, or a synthesis gas, which serves to supply thermal energy to an exhaust aftertreatment device not shown in Figure 1. In some embodiments, instead of the exhaust flap 7, another device can be used that generates a pressure difference between the inlet 21 and the outlet 22, for example, the turbine of an exhaust gas turbocharger.

[0058] Inside the housing 25 is a catalyst support 5. The catalyst support 5 can contain or consist of a porous material, for example, a porous molded body, a knitted fabric, a braid, a nonwoven fabric, a woven fabric, a knitted fabric, or a sheet metal structure. The catalyst support 5 can either be catalytically active itself or be provided with a catalytically active coating.

[0059] A fuel plate 6 is located on one side of the catalyst carrier 5. A perforated plate 4 is located on the opposite side of the catalyst carrier 5. The perforated plate 4 has a plurality of through-holes 41 through which the exhaust gas or the partial flow 351 can enter the catalyst carrier 5. The exhaust gas supplied to the catalyst carrier 5 in this way serves as an oxidizing agent. If the residual oxygen content of the exhaust gas is too low, ambient air can also be supplied to the heating catalyst. An embodiment of a perforated plate 4, which can be used in at least some embodiments of the heating catalyst, is explained in more detail in connection with Figures 4 and 5.

[0060] A fuel plate 6 is arranged on the opposite side of the catalyst support 5. Fuel is supplied to the fuel plate 6 via a fuel line 62, which is connected to an optional fuel pump 65. The fuel plate 6 is designed and intended to distribute the fuel within the plane defined by the fuel plate 6, so that it can be vaporized there by the application of heat and supplied to the catalyst support 5 in gaseous form. After the fuel has reacted at the catalyst or the catalyst support 5, it leaves the catalyst support 5 as product gas 352. 31974 PWO Heating catalyst 2. One possible embodiment of a fuel plate 6, which can be used in at least some embodiments, is explained in more detail with reference to Figures 2, 3 and 4.

[0061] Figures 2, 3, and 4 illustrate one embodiment of a fuel plate 6. Figure 2 shows a top view of a fuel plate, and Figure 3 shows the section marked "A" at an enlarged scale. Figure 4 shows a cross-section through bore 63.

[0062] As can be seen in Figure 2, the fuel plate 6 is approximately circular in the illustrated embodiment. In other embodiments, the fuel plate can also be polygonal. In this case, the perforated plate 4 and / or the catalyst carrier 5 and / or the housing 25 can optionally also be polygonal. The heating catalyst 2 and the fuel plate 6 are designed and intended to be oriented approximately vertically when the heating catalyst is in operation. Thus, gravity acts within the plane defined by the fuel plate 6. Figures 2 and 3 show the side of the fuel plate 6 facing the catalyst carrier 5.

[0063] As can be seen from the figures, a plurality of channels 61 are incorporated into the fuel plate 2. The channels 61 serve as a transport device that distributes the applied fuel within the plane defined by the fuel plate. This uniform distribution prevents overheating in certain areas of the catalyst support as well as the formation of coking or deposits due to cold spots. The channels 61 shown in Figure 2 thus result in a uniform temperature distribution within the heating catalyst.

[0064] The channels 61 comprise at least one first channel 611, which originates from a bore 63. The bore 63 extends from the side of the fuel plate facing away from the catalyst carrier 5 to the side facing the catalyst carrier 5. The bore 63 is connected to the fuel line 62, so that the fuel supplied by the optional fuel pump 65 can exit the bore 63. The exiting fuel is received by the first channel 611. As shown in Figure 2, the fuel plate in the illustrated embodiment has two first channels 611a and 611b. 31974 PWO which are arranged symmetrically to bore 63. In other embodiments, a larger number of bores and / or a larger or smaller number of first channels 611 may also be present.

[0065] In the illustrated embodiment, the first channel 611 is inclined at approximately 20° to 30° to the horizontal in the installed position of the heating catalyst 2. This causes the fuel to flow through the first channel 611 by gravity.

[0066] A plurality of second channels 612 branch off from the first channel 611, which, in the installed position of the heating catalyst 2, are inclined at approximately 40° to approximately 90° to the horizontal. In the illustrated embodiment, the second channels 612 essentially run vertically downwards, but they also incorporate further structures to reduce the flow velocity, as described below. Due to the general direction, which is essentially vertical downwards, the fuel is distributed evenly along the fuel plate, both in width and height. The channels 611 can be designed such that, at partial load, the fuel is already completely vaporized before it reaches the end of the second channels 612. In this respect, only a portion of the fuel plate 6 is actually used for fuel vaporization.With higher power output and higher fuel supply, an increasingly larger sub-area is then put into operation until the fuel reaches the ends of the second channels 612 or has completely evaporated shortly before.

[0067] As can be seen in Figure 3, the second channels 612 have structures for reducing the flow velocity. For this purpose, the second channels 612 are subdivided along their course into a plurality of first and second longitudinal sections 641, 642, 643, and 644. Furthermore, the second channels 612 have a plurality of branching points 645. Between adjacent branching points 645, the first and second longitudinal sections initially diverge and then converge. As can be seen in Figure 3, the first and second longitudinal sections 641 and 642 diverge starting from the branching point above them. After a predetermined length, the channel makes a bend, so that the 31974 PWO Subsequent longitudinal sections 443 and 444 converge again towards the downstream branching point 645.

[0068] In some embodiments, the first and second longitudinal sections can have an angle of approximately 70° to approximately 110° adjacent to each other. In the illustrated embodiment, the first and second longitudinal sections enclose an angle of approximately 90°, so that they form approximately a square. In other embodiments, the first and second longitudinal sections can also form a rectangle or a rhombus. By varying the inclination, the influence of gravity can be controlled, so that the flow velocity of the fuel in the second channels 612 can be slowed down or increased. The angle between adjacent first and second longitudinal sections, as well as their length and the number of branching points 645, can be optimized in computer simulations to create an optimal flow field on the fuel plate for a specific heating catalyst in a specific application.

[0069] As can be seen in Figure 3, the width of the first channels 611 decreases starting from the bore 63. This takes into account the fact that the entire supplied quantity of fuel must be transported at the beginning of the first channels 611. As the length of the first channel 611 increases, more and more fuel is discharged into the second channels 612, so that the transported quantity of fuel decreases. For this, only a smaller cross-section of the first channel 611 is required. Alternatively or additionally, the depth of the channels 611 can also decrease along their length. In some embodiments, the width of the first channel 611 can vary while maintaining a constant depth, whereas the second channels 612 have a constant width while their depth steadily decreases.

[0070] Figure 4 shows the cross-section through a fuel plate 6 in the area of ​​the fuel inlet or bore 63. The bore 63 extends from the side of the fuel plate 6 facing away from the catalyst carrier 5 to the side facing the catalyst carrier 5. A line 8 is attached to the side facing away from the catalyst carrier 5, which carries a first longitudinal section 31974 PWO 81 has a constant cross-section. A second longitudinal section 82 adjoins this, in which the cross-section increases from the first longitudinal section 81 to the opening in the fuel plate 6. In some embodiments, the second longitudinal section 82 may have a conical cross-section. As a result, the cross-section of the bore 63 increases from the side of the fuel plate 6 facing away from the catalyst carrier 5 to the side facing the catalyst carrier 5. This can reduce the flow velocity of the incoming fuel, thus preventing fuel from overflowing from the channels.

[0071] Figure 5 shows the relationship between the horizontal and vertical propagation velocities of the fuel on the fuel plate versus the power output. The propagation velocities were measured using diesel fuel at room temperature, which was supplied through bore 63, while the wetting behavior of the fuel plate was optically recorded using a camera. The resulting propagation velocities VLI in the horizontal direction and VL2 in the vertical direction were compared, yielding the quotient VLI / VL2 as a dimensionless quantity. This value is plotted on the ordinate in Figure 5.

[0072] The amount of fuel supplied varies with the power output of the heating catalyst, with the fuel quantity considered in Figure 5 corresponding to a power range of 4 kW to 45 kW. The power output is plotted on the abscissa in Figure 5. The following measured values ​​were obtained: [Table 1]

[0073] As Figure 5 and the preceding measurements show, the horizontal propagation speed is greater than the vertical propagation speed for all power levels. The measurements closely follow a logarithmic curve (R² = 0.9464). This means that the full width of the fuel plate is utilized across the entire power range. The higher the power, the further down the fuel flows along the second channels 612, so that with increasing power, an increasingly larger area is utilized. 31974 PWO The reaction surface is optimally utilized due to the geometry of the fuel plate shown in Fig. 2, so that the fuel plate requires only one bore 63. This simplifies the control of the heating catalyst.

[0074] Naturally, the invention is not limited to the embodiments described. The foregoing description is therefore not to be considered limiting, but rather explanatory. The following claims are to be understood as meaning that a named feature is present in at least one embodiment of the invention. This does not preclude the presence of further features. Where the claims and the foregoing description define "first" and "second" embodiments, this designation serves to distinguish between two similar embodiments without establishing any hierarchy. 31974 PWO

Claims

Claims

1. A heating catalyst (2) for an exhaust aftertreatment device or reformer, which is configured to react fuel with an oxidizing agent, wherein the heating catalyst (2) has a housing (25) having an inlet (21) and an outlet (22), wherein the inlet (21) is configured to supply the oxidizing agent and the outlet (22) is configured to discharge a product gas, and wherein the heating catalyst (2) further comprises a catalyst support (5) arranged in the housing (25), wherein a fuel plate (6) is arranged on one side of the catalyst support (5), which is configured to supply the fuel to the catalyst support (5), and a perforated plate (4) is arranged on one side of the catalyst support (5) opposite the fuel plate (6), which is configured to supply the oxidizing agent to the catalyst support (5), characterized in thatthat the fuel plate (6) is provided with a transport device which has a plurality of channels (61) which are introduced into the side of the fuel plate (6) facing the catalyst carrier (5) and are at least partially open towards the catalyst carrier (5).

2. A heating catalyst (2) for an exhaust aftertreatment device or a reformer, which is configured to react fuel with an oxidizing agent, wherein the heating catalyst (2) has a housing (25) having an inlet (21) and an outlet (22), wherein the inlet (21) is configured to supply the oxidizing agent and the outlet (22) is configured to discharge a product gas, and wherein the heating catalyst (2) further comprises a catalyst support (5) arranged in the housing (25), wherein a fuel plate (6) is arranged on one side of the catalyst support (5), which is configured to supply the fuel to the catalyst support (5) and on one side opposite the fuel plate (6) of the 31974 PWO a perforated plate (4) is arranged on the catalyst support (5), which is designed to supply the oxidizing agent to the catalyst support (5), characterized in that the heating catalyst (2) further comprises a porous shaped body which is arranged between the catalyst support (5) and the fuel plate (6), wherein the shaped body is provided with a transport device which has a plurality of channels which are introduced into the side of the shaped body facing the fuel plate (6) and are at least partially open towards the fuel plate (6).

3. Heating catalyst according to claim 1 or 2, characterized in that the fuel plate (6) has at least one bore (63) which extends from the side facing away from the catalyst carrier (5) to the side of the fuel plate (6) facing the catalyst carrier (5) and which opens into a first channel (611 ).

4. Heating catalyst according to claim 3, characterized in that bore (63) has a cross-section which increases from the side facing away from the catalyst carrier (5) to the side of the fuel plate (6) facing the catalyst carrier (5).

5. Heating catalyst according to claim 3 or 4, characterized in that bore (63) has a conical cross-section.

6. Heating catalyst according to one of claims 1 to 5, characterized in that the cross-sectional area of ​​the channels (61) decreases along their course.

7. Heating catalyst according to claim 6, characterized in that the width of the channels (61) decreases along their course and / or that the depth of the channels (61, 611a, 611b) decreases along their course and / or that the width of the channels (61) decreases along their course from about 5 mm to about 0.5 mm or from about 3 mm to about 0.8 mm and / or that the depth of the channels (61) decreases along their course 31974 PWO decreases from about 1.0 mm to about 0.05 mm or from about 0.7 mm to about 0.1 mm.

8. Heating catalyst according to one of claims 1 to 7, characterized in that the first channel (611 ) is inclined by about 20° to about 30° to the horizontal in the installation position of the heating catalyst (2).

9. Heating catalyst according to one of claims 1 to 8, characterized in that a plurality of second channels (612) branch off from the first channel (611 ), which are inclined by about 40° to about 90° to the horizontal in the installation position of the heating catalyst (2).

10. Heating catalyst according to one of claims 1 to 9, characterized in that the second channels (612) have a plurality of first and second longitudinal sections (641 , 642, 643, 644) and a plurality of branching points (645) in their course, wherein the first and second longitudinal sections (641 , 642, 643, 644) initially diverge and then converge between adjacent branching points (645).

11. Heating catalyst according to claim 10, characterized in that adjacent first and second longitudinal sections (641 , 642, 643, 644) enclose an angle of about 70° to about 110° or of about 80° to about 100° or of about 85° to about 95°.

12. Heating catalyst according to one of claims 1 to 11, characterized in that it is arranged such that at all operating points a horizontal component of the propagation velocity VLI of the fuel metered onto the fuel plate is greater than a vertical component of the propagation velocity VL2 of the fuel metered onto the fuel plate and / or that the ratio of the horizontal component of the propagation velocity VLI of the fuel metered onto the fuel plate to the vertical component of the propagation velocity VL2 of the fuel metered onto the fuel plate against the power of the heating catalyst follows a logarithmic curve. 31974 PWO

13. Heating catalyst according to claim 1 or according to any one of claims 3 to 12, further comprising a porous shaped body which is arranged between the catalyst carrier (5) and the fuel plate (6).

14. Heating catalyst according to claim 13, characterized in that the molded body is provided with a transport device which has a plurality of channels which are introduced into the side of the molded body facing the fuel plate (6) and are at least partially open towards the fuel plate (6).

15. Heating catalyst according to claim 2 or 13 or 14, characterized in that the shaped body contains or consists of a woven fabric or knitted fabric or a nonwoven fabric or a sintered body or that the shaped body is joined to the fuel plate (6) in a material-bonded manner on the side of the fuel plate (6) facing the catalyst support (5).

16. Internal combustion engine with at least one heating catalyst according to any one of claims 1 to 15. 31974 PWO

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