Exhaust gas cooling device

Abstract

An exhaust gas cooling device (1) for a hot gas source (8), wherein the exhaust gas cooling device (1) comprises: a housing (3.6) connectable to an exhaust pipe (1.1) of the hot gas source (8) with an axis of symmetry (3.5), a Venturi assembly (5) coupled to the housing (3.6) for introducing exhaust gas (1.2) and ambient air (9), and an exhaust gas / ambient air mixture discharged into the environment (2), wherein the Venturi assembly (5) has a Venturi channel (5.1) which can be fluidically coupled to the exhaust pipe (1.1) and an inlet opening (5.2) for ambient air which is limited by the Venturi channel (5.1) and the exhaust pipe (1.1), the Venturi channel (5.1) serves to guide exhaust gas-ambient air mixture, wherein the Venturi channel (5.1) has an outlet opening (5.3) and the outlet line (2) has an inlet opening (2.1), wherein the outlet opening (5.3) and the inlet opening (2.1) are spaced apart, and wherein the Venturi channel (5.1) and the outlet pipe (2) open into the housing (3.6), characterized by a) that the outlet opening (5.3) of the Venturi channel (5.1) and the inlet opening (2.1) of the outlet line (2) are positioned in alignment, wherein a deflection element (4) is provided between the outlet opening (5.3) and the inlet opening (2.1) which causes a deflection in a direction Rq with a directional component perpendicular to the direction of the gas outlet A of the outlet opening (5.3), or b) that the outlet opening (5.3) of the Venturi channel (5.1) causes a gas outlet A directed radially to the axis of symmetry (3.5), wherein the outlet line (2) with the inlet opening (2.1) causes a gas inlet E directed parallel to the axis of symmetry (3.5).

Description

[0001] The invention relates to an exhaust gas cooling device for a hot gas source such as an internal combustion engine or a fuel cell, comprising a housing with an axis of symmetry that can be connected to an exhaust gas line of the internal combustion engine or the cell, and a Venturi assembly coupled to the housing for introducing exhaust gas and ambient air, and an exhaust gas-ambient air mixture discharged into the environment, wherein the Venturi assembly has a Venturi channel that can be fluidically coupled to the exhaust gas line and an inlet opening for ambient air bounded by the Venturi channel and the exhaust gas line, wherein the Venturi channel serves to guide the exhaust gas-ambient air mixture, wherein the Venturi channel has an outlet opening and the outlet line has an inlet opening, wherein the outlet opening and the inlet opening are spaced apart, and wherein the Venturi channel and the outlet line terminate in the housing.

[0002] An exhaust gas cooling device with a Venturi arrangement for supplying ambient air is already known from US Patent 8,549,850 B2. The exhaust gas cooling device has several exhaust gas inlet channels and a Venturi tube located downstream. In addition, several inlet openings for ambient air are provided. The exhaust gas and the drawn-in ambient air are mixed via the Venturi tube and discharged into the environment.

[0003] DE 37 88 449 T2 shows an exhaust silencer for a gas turbine with a Venturi assembly for guiding exhaust gas-ambient air mixture and with an outlet pipe arranged at a distance therefrom.

[0004] US Patent 4,209,493 A shows an exhaust gas cleaning device with a Venturi assembly for guiding exhaust gas-ambient air mixture and an outlet pipe arranged at a distance therefrom.

[0005] US 4 579 194 A and JP S49- 84 505 U also show an exhaust gas purification device with a Venturi assembly for guiding exhaust gas-ambient air mixture and an outlet pipe arranged at a distance from it.

[0006] The present invention is aimed at overcoming one or more of the problems or disadvantages associated with the prior art. In particular, the invention is based on the objective of designing and arranging an exhaust gas cooling device in such a way as to ensure improved mixing of the exhaust gas-ambient air mixture.

[0007] The object of the present invention is achieved by an exhaust gas cooling device for a hot gas source according to claim 1. The dependent claims relate to preferred embodiments of the invention. The object is achieved, in particular, according to the invention, in that a) the outlet opening of the Venturi channel and the inlet opening of the outlet line are positioned in alignment, wherein a deflecting element is provided between the outlet opening and the inlet opening, which causes a deflection in a direction Rq with a directional component perpendicular to the direction of the gas outlet A of the outlet opening, or that b) the outlet opening of the Venturi channel causes a gas outlet A directed radially to the axis of symmetry, wherein the outlet line with the inlet opening causes a gas inlet E directed parallel to the axis of symmetry.This ensures that the exhaust gas / ambient air mixture is guided within the housing for a longer time and over a longer distance, resulting in improved mixing before the exhaust / ambient air mixture is released into the environment via the exhaust pipe. Despite the aforementioned offset, the deflection element also results in an increased flow path within the mixing chamber. The radial outflow from the Venturi channel guarantees at least a 90° deflection of the gas flow and the associated increased flow path.

[0008] It can also be advantageous if the housing defines a mixing chamber with a chamber wall, wherein the outlet opening of the Venturi channel has an outlet cross-section Qv and the mixing chamber forms a flow cross-section Qm for the exhaust gas-ambient air mixture exiting the Venturi channel, with Qm >= f Qv, with 2 <= f <= 12, in particular with f = 6, f = 7 or f = 8. The enlargement of the flow cross-section at the inlet to the housing or the mixing chamber reduces the flow velocity, thus resulting in a longer residence time in the housing.

[0009] Furthermore, it can be advantageous if the outlet opening of the Venturi channel and the inlet opening of the exhaust pipe are arranged off-axis. This off-axis arrangement, or the offset achieved by different orientations of the openings, increases the path that the exhaust gas-ambient air mixture must travel within the housing. The off-axis, offset, or orientation refers to the respective central axis of the outlet opening and inlet opening, or to the flow vector defined by the respective central axis, such as gas outlet A and gas inlet E. Off-axis arrangement can also be achieved by having the flow vectors have different orientations.

[0010] Of particular importance for the present invention is the fact that the mixing chamber has at least a partially round cross-sectional shape Q with respect to the axis of symmetry, or that turbulence-generating elements are provided on the chamber wall, wherein the gas outlet A, upon impact of the gas flow on the round chamber wall or on the turbulence-generating element, causes at least one double vortex in the mixing chamber, directed in the opposite direction with respect to the axis of symmetry. The at least one double vortex also extends the flow path, and thus the residence time. The round shape of the chamber wall can be circular, oval, or other round. The fin- or wing-shaped turbulence-generating element can also be formed by the chamber wall or be an integral part of the chamber wall. An angular cross-sectional shape Q of the mixing chamber is also possible if corresponding turbulence-generating elements are provided on the chamber wall.

[0011] In connection with the design and arrangement according to the invention, it can be advantageous if the Venturi channel forms a mixing stage Mv with a volume Vv, if the mixing chamber forms a mixing stage Mm with a volume Vm, and if the outlet line forms a mixing stage Ma with a volume Va, wherein the following applies to the ratio S1 of Vm to Vv: 25 >= S1 >= 2, in particular 16 >= S1 >= 12, and / or where the ratio S2 of Vm to Va is: 25 >= S2 >= 2, in particular 16 >= S2 >= 12. The relative size of the mixing chamber is also crucial for the length of the achievable flow paths of the gas stream within the otherwise closed mixing chamber. A relatively large mixing chamber ensures relatively large or long flow paths.

[0012] It can also be advantageous if sound-absorbing materials are provided within the mixing chamber and / or upstream of the Venturi assembly.

[0013] Furthermore, it can be advantageous to include additional turbulence or deflection devices within the mixing chamber. This further improves the mixing process.

[0014] Furthermore, it can be advantageous to have a guide plate upstream of the ambient air inlet or at the ambient air inlet to capture ambient air or airflow, in order to actively increase the amount of ambient air supplied.

[0015] Ambient air can also be supplied directly via the ambient air inlet. In this case, the inlet opens directly into the surrounding environment. An ambient air inlet that would otherwise need to pass through the housing is therefore unnecessary.

[0016] Furthermore, it can be advantageous to provide a bypass arrangement with a bypass line through which the exhaust gas can be routed past the cooling device.

[0017] Further advantages and details of the invention are explained in the claims and the description and illustrated in the figures. These show: Fig. 1a a sectional view BB from Fig. 2; Fig. 1b a sectional view of an alternative embodiment; Fig. 2 a sectional view AA from Fig. 3; Fig. 3 a schematic diagram; Fig. 4 different cross-sectional shapes; Fig. 5 a schematic diagram of a further embodiment.

[0018] One in Fig. The exhaust gas cooling device 1 shown in section BB is coupled to an exhaust gas line 1.1 for exhaust gas 1.2. The exhaust gas line 1.1 is an outlet pipe of an exhaust gas purification system 8.2, such as a catalyst housing. The exhaust gas cooling device 1 has a housing 3.6 with a chamber wall 3.4, which delimits a mixing chamber 3.1. Inside the housing 3.6, a Venturi assembly 5 is provided with a Venturi channel 5.1, which is fluidically coupled to the exhaust gas line 1.1 and thus blown upon. The Venturi assembly 5 also has an inlet opening 5.2 for ambient air 9, which is delimited by the exhaust gas line 1.1 on one side and the Venturi channel 5.1 on the other. The ambient air inlet 5.2 is connected to an ambient air duct 3.2, which circumferentially surrounds the Venturi channel 5.1. The ambient air duct 3.2 is in turn connected via an air inlet 3.6 that passes through the housing 3.6.3 is coupled to the environment, so that the ambient air 9 is guided via the ambient air inlet 3.3 and the ambient air duct 3.2 to the inlet opening 5.2. The ambient air inlet 3.3 may have a guide plate (not shown here) for capturing ambient air.

[0019] The Venturi channel 5.1 thus guides the exhaust gas-ambient air mixture towards an axis of symmetry 3.5 of the housing 3.6 or the mixing chamber 3.1, wherein the Venturi channel 5.1 has a 90° bend at its end, so that a gas outlet A occurs radially towards the axis of symmetry 3.5 via an outlet opening 5.3 of the Venturi channel 5.1. The exhaust gas-ambient air mixture exiting the outlet opening 5.3 encounters, as shown in Fig. 2 shown, onto the upper chamber wall 3.4 or a turbulence means 7 arranged there, so that due to the following Fig. The round cross-sectional shape Q shown in Figure 2 forms an opposing double vortex of the exhaust gas-ambient air mixture.

[0020] The housing 3.6 also has an outlet pipe 2 with an inlet opening 2.1, through which the exhaust gas-ambient air mixture is discharged from the housing 3.6 or the mixing chamber 3.1 to the outside or into the environment. The inlet opening 2.1 ensures an axially oriented gas inlet E of the exhaust gas-ambient air mixture. The non-aligned, different, and offset orientation of the gas outlet A and gas inlet E ensures a correspondingly long flow path within the mixing chamber 3.1. The outlet opening 5.3 of the Venturi channel has an outlet cross-section Qv that is significantly smaller than the flow cross-section Qm provided to the exhaust gas-ambient air mixture by the mixing chamber 3.1. This results in a corresponding deceleration of the flow velocity of the exhaust gas-ambient air mixture and, consequently, an increased residence time within the mixing chamber 3.1.

[0021] Within the mixing chamber 3.1, a further deflecting device 7.1 is also provided for directing the gas flow on its way to the inlet opening 2.1.

[0022] Upstream of the Venturi assembly 5, a sound damping medium 6 is provided, onto which the exhaust gas 1.2 immediately impinges after exiting an exhaust gas purification system 8.2.

[0023] The exhaust gas cooling device 1 has three mixing stages: the mixing stage Mv of the Venturi channel 5.1 with a volume Vv, the mixing stage Mm of the mixing chamber 3.1 with a volume Vm, and the mixing stage Ma of the outlet pipe 2 with a volume Va. The volume Vm of the mixing stage Mm is approximately a factor S1, S2 of 14 larger than the volume Vv, Va of the other two mixing stages Mv, Ma.

[0024] In the exemplary embodiment according to Fig. In 1b, the gas outlet A and the gas inlet E are oriented in the same direction. Furthermore, the outlet opening 5.3 of the Venturi channel and the inlet opening 2.1 of the outlet line 2 are aligned. To prevent the inlet opening 2.1 from being directly blown by the Venturi channel 5.1, a deflecting element 4 is provided. This element directs the gas flow radially outwards into the mixing chamber 3.1, ensuring a sufficiently long flow path to achieve the desired mixing of the exhaust gas-ambient air mixture. The deflecting element 4 redirects the gas outlet A in a direction Rq with a directional component radial to the axis of symmetry 3.5.

[0025] After Fig. Figure 3 shows the exhaust gas cooling device 1 downstream of an exhaust gas purification system 8.2. The exhaust gas purification system 8.2 in turn is connected to an internal combustion engine 8 via an exhaust pipe section 8.1. The exhaust gas 1.2, cooled in this respect, leaves the exhaust system via the outlet pipe 2.

[0026] In Fig. 2 shows the section view AA from Fig. 3. Also shown is section BB for the embodiment shown in the illustration. Fig. 1a.

[0027] Ambient air 9 is guided through the ambient air inlet 3.3 to the ambient air duct 3.2, which circumferentially surrounds the Venturi channel 5.1. This allows the ambient air 9 to enter the Venturi channel 5.1 through the inlet opening 5.2 located between the Venturi channel 5.1 and the exhaust pipe 1.1. The exhaust gas-ambient air mixture then exits the Venturi channel 5.1 radially upwards and encounters the concave chamber wall 3.4 or the optionally positioned vortex generator 7. This creates a counter-rotating double vortex, which in turn ensures a corresponding flow path for the exhaust gas-ambient air mixture within the mixing chamber 3.1 before the exhaust gas-ambient air mixture is discharged to the outside or into the environment through the inlet opening 2.1 of the exhaust pipe 2.

[0028] The aforementioned concave shape of the chamber wall 3.4 in the area where the exhaust gas-ambient air mixture from the Venturi channel 5.1 enters the chamber wall 3.4 ensures the formation of a double vortex. A concave shape is achieved by a correspondingly round or oval cross-sectional shape Q of the chamber wall 3.4, as shown in Fig. Figure 4 outlines. Of course, other cross-sectional shapes are also possible, which, upon impact of the gas flow, ensure the formation of a corresponding double or single vortex, thus increasing the overall flow path and consequently the residence time of the gas flow within the mixing chamber 3.1. A rectangular cross-sectional shape Q, as also shown in Figure 4, is also possible. Fig. As shown in section 4, appropriate turbulence-inducing agents are required on the chamber wall.

[0029] The after Fig.The embodiment of the exhaust gas cooling device 1 shown in Figure 5 is arranged directly downstream of a hot gas source 8, such as an internal combustion engine or a fuel cell. Furthermore, the exhaust gas cooling device 1 has a bypass arrangement 8.3 with a bypass line 8.4, through which the exhaust gas can be routed past the exhaust gas cooling device 1. Reference symbol list 1 Exhaust gas cooling device 1.1 Exhaust pipe, hot gas pipe 1.2 Exhaust gas 2 Outlet pipe 2.1 Inlet opening 3.1 Mixing chamber 3.2 Ambient air duct 3.3 Ambient air intake 3.4 Chamber wall 3.5 Axis of symmetry 3.6 Housing 3.7 Guide plate 4 Deflection element 5 Venturi assembly 5.1 Venturi Channel 5.2 Ambient air inlet 5.3 Venturi channel outlet 6 sound-absorbing agents 7 Vulcanizing agents 7.1 other turbulence or deflection devices 8 Internal combustion engine, fuel cell, hot gas source 8.1 Exhaust pipe section 8.2 Exhaust gas purification system 8.3 Bypass arrangement 8.4 Bypass line 9 Ambient air A gas leak E Gas Inlet f factor Ma mixing stage mm mixing stage Mv mixing stage Q Cross-sectional shape Qm flow cross-section Qv outlet cross-section Rq direction S1 ratio S2 ratio Va volume Vm volume Vv volume

Claims

[1] An exhaust gas cooling device (1) for a hot gas source (8), wherein the exhaust gas cooling device (1) comprises: a housing (3.6) connectable to an exhaust pipe (1.1) of the hot gas source (8) with an axis of symmetry (3.5), a Venturi assembly (5) coupled to the housing (3.6) for introducing exhaust gas (1.2) and ambient air (9), and an exhaust gas / ambient air mixture discharged into the environment (2), wherein the Venturi assembly (5) has a Venturi channel (5.1) which can be fluidically coupled to the exhaust pipe (1.1) and an inlet opening (5.2) for ambient air which is limited by the Venturi channel (5.1) and the exhaust pipe (1.1), the Venturi channel (5.1) serves to guide exhaust gas-ambient air mixture, wherein the Venturi channel (5.1) has an outlet opening (5.3) and the outlet line (2) has an inlet opening (2.1), wherein the outlet opening (5.3) and the inlet opening (2.1) are spaced apart, and wherein the Venturi channel (5.1) and the outlet pipe (2) open into the housing (3.6), characterized by , a) that the outlet opening (5.3) of the Venturi channel (5.1) and the inlet opening (2.1) of the outlet line (2) are positioned in alignment, wherein a deflection element (4) is provided between the outlet opening (5.3) and the inlet opening (2.1) which causes a deflection in a direction Rq with a directional component perpendicular to the direction of the gas outlet A of the outlet opening (5.3), or b) that the outlet opening (5.3) of the Venturi channel (5.1) causes a gas outlet A directed radially to the axis of symmetry (3.5), wherein the outlet line (2) with the inlet opening (2.1) causes a gas inlet E directed parallel to the axis of symmetry (3.5). [2] The exhaust gas cooling device (1) according to claim 1, characterized by, that the housing (3.6) defines a mixing chamber (3.1) with a chamber wall (3.4), wherein the outlet opening (5.3) of the Venturi channel (5.1) has an outlet cross-section Qv and the mixing chamber (3.1) forms a flow cross-section Qm for the exhaust gas-ambient air mixture exiting the Venturi channel (5.1), wherein the following applies: Qm >= f Qv and 2<=f<=10. [3] The exhaust gas cooling device (1) according to characterized by , that the outlet opening (5.3) of the Venturi channel (5.1) and the inlet opening (2.1) of the outlet line (2) are arranged outside of an alignment. [4] The exhaust gas cooling device (1) according to claim 2 or 3, characterized bythat the mixing chamber (3.1) has at least a partially round cross-sectional shape Q with respect to the axis of symmetry (3.5) or that turbulence means (7) are provided on the chamber wall (3.4), wherein the gas outlet A, when the gas flow hits the round chamber wall (3.4) or the turbulence means (7), causes at least one double vortex in the mixing chamber (3.1) directed in the opposite direction with respect to the axis of symmetry (3.5). [5] The exhaust gas cooling device (1) according to any one of claims 2 to 4, characterized by , that the Venturi channel (5.1) forms a mixing stage Mv with a volume Vv and that the mixing chamber (3.1) forms a mixing stage Mm with a volume Vm and that the outlet line (2) forms a mixing stage Ma with a volume Va, where the following applies to the ratio S1 of Vm to Vv: 25 >= S1 >= 2, and / or where the following applies to the ratio S2 of Vm to Va: 25 >= S2 >= 2. [6] The exhaust gas cooling device (1) according to any one of claims 2 to 5, characterized by , that sound damping means (6) are provided within the mixing chamber (3.1) and / or upstream of the Venturi assembly (5). [7] The exhaust gas cooling device (1) according to any one of claims 2 to 6, characterized by , that further turbulence or deflection means (7.1) are provided within the mixing chamber (3.1). [8] The exhaust gas cooling device (1) according to any of the preceding claims, characterized by , that upstream of the inlet opening (5.2) for ambient air a guide plate (3.7) is provided for capturing ambient air (9). [9] The exhaust gas cooling device (1) according to any one of the preceding claims, characterized by , that a bypass arrangement (8.3) with a bypass line (8.4) is provided.

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