An exhaust gas subsystem

Abstract

The present invention relates to an exhaust gas subsystem 1 for an internal combustion engine, comprising: a catalytic converter 2 having an inlet section 3 for introducing exhaust gas flow 4.3 into an outer casing 2; and a supply line 5 for secondary gas 5.3, the supply line 5 having an inflow element 5.1 at its end, the inflow element being open at the inlet section 3; the outer casing 2.1 having an inlet opening 3.2 for exhaust gas; an external heating element 6 for heating the secondary gas 5.3 and generating hot gas is disposed upstream of the inflow element 5.1 in the supply line 5; at least one inflow opening 5.2 in the outer casing 2 is assigned to the inflow element 5.1, through which the hot gas can be delivered to the inlet section 3.

Description

Technical Field

[0001] This invention relates to an exhaust gas subsystem for an internal combustion engine, comprising: a catalytic converter housing having an inlet section and an inlet opening for introducing an exhaust gas stream or a main exhaust gas stream into the catalytic converter housing; and a supply line for secondary gas without an exhaust gas stream, the supply line having an inflow element at its end through which the secondary gas stream is supplied to the main exhaust gas stream; the inflow element is preferably placed directly upstream of the catalytic converter or upstream of the catalytic converter housing; wherein a heating element for heating the secondary gas is provided in the supply line upstream of the inflow element. The exhaust gas subsystem is part of an exhaust system extending from a main pipe to an exhaust gas end pipe. The internal combustion engine may be part of a stationary engine or machine of a motor vehicle or vessel. Background Technology

[0002] An exhaust gas purification system is known from EP 1 333 169 B1, which discloses a supply device for ambient air, which can be supplied through a duct and annular pipe in the housing upstream of a particulate filter.

[0003] A burner with an external air supply is known from US 8,991,157 B2 for heating exhaust gas flow to regenerate a downstream particulate filter.

[0004] A plasma burner with an external air supply is known from US 10,174,567 B2, which is used to heat the exhaust gas stream to supply a downstream SCR catalytic converter.

[0005] An exhaust system for a diesel engine is known from EP 1 333 169 B1, which includes a particulate filter, an upstream oxidation catalytic converter, and a controllable secondary air supply device. The secondary air supply device has a perforated annular pipe disposed in the inlet section of the housing.

[0006] A subsystem for exhaust gas in an internal combustion engine is known from DE 39 19 343 A1, comprising a catalytic converter housing having an integral inlet section and an inlet opening for introducing exhaust gas flow. The inlet opening is part of a supply line for secondary gas, the supply line having a heating element for heating the secondary gas. Summary of the Invention

[0007] This invention is based on the problem of designing and arranging an exhaust gas subsystem for an internal combustion engine to enable improved cold start of the catalytic converter and optimization of its temperature control.

[0008] According to the invention, the problem is solved by including at least one inflow opening at or within the inlet section, through which heated secondary gas can be conveyed to the exhaust gas flow. The inflow element, together with the inlet section designed as an outer casing, defines a collection chamber from which the secondary gas can be guided or conveyed via the inflow opening to the exhaust gas delivery portion of the inlet section. Each inflow opening includes an opening cross-section and an opening axis. This ensures that externally heated gas, particularly ambient air used to preheat the catalytic converter, can be delivered to the catalytic converter during the cold start of the internal combustion engine. Furthermore, the temperature of the catalytic converter can be controlled after the cold start during normal operation of the internal combustion engine. The heating element is independent of the internal combustion engine; it is not part of the internal combustion engine. More precisely, the heating element can operate independently of the internal combustion engine. The heating element can be actively controlled, i.e., it can be turned on and off. The heating element can also be controlled in such a way that the temperature of the secondary gas can be set to at least one or more predetermined temperatures. In this respect, the heating element can be considered external because it is not part of the exhaust system, since secondary gas, not exhaust gas, flows through the heating element. The heated secondary gas is delivered from the external heating element through the environment to the catalytic converter housing via a supply line. The heating element is part of a cold start unit that supplies hot gas to the exhaust gas stream at a predetermined temperature, independent of the internal combustion engine's exhaust gas temperature. The catalytic converter in the housing is positioned directly downstream of the inlet section to avoid heat loss. The heating element can be designed as a burner to generate hot gas or as an electric heating element to generate hot gas. The hot gas must be separated from the hot or unheated exhaust gas stream from the internal combustion engine. The supply line and heating element are arranged outside the exhaust gas conduction element of the exhaust gas subsystem, and these elements conduct exhaust gas from the heating element to the corresponding exhaust gas conduction element of the exhaust gas subsystem or to a corresponding location in the inflow element. The inflow element can also be one or more feed nozzles.

[0009] The inflow element can be located in or on the inlet section. The collection chamber formed in this way is easily accessible from the outside. Furthermore, the flow path of the engine exhaust gas within the inlet section is not strained or reduced by the inflow element. The corresponding opening axis is preferably aligned perpendicularly to the surface of the inlet section or perpendicularly to the surface of the recess. Inclined alignment of the corresponding opening axis is also possible. In this respect, the collection chamber refers to the inflow chamber and outflow chamber for secondary gases. If the inlet section is single-walled, the outer casing also includes an outer side. If the inlet section is formed as an insulated air gap, i.e., double-walled or integrated into another casing, the outer side is also the side of the inlet section facing away from the exhaust gas.

[0010] The problem is also addressed by an exhaust system that includes an exhaust gas subsystem as defined above. The exhaust system further includes at least one catalytic converter disposed within a catalytic converter housing and a corresponding exhaust pipe located at an end of the catalytic converter housing for connecting the exhaust system to other components of the exhaust system.

[0011] The problem is also addressed by a method for operating the aforementioned exhaust system, in which the secondary gas is heated by means of a heating element to regulate the temperature of the catalytic converter. The catalytic converter is heated to its effective operating temperature. During cold start, the catalytic converter can be heated to the operating temperature by means of a heating element. During normal operation, after the cold start, the temperature of the catalytic converter can be adjusted to the desired temperature at at least one additional time point.

[0012] Advantageously, the inflow element is located at the inlet section and / or the inflow opening is located within the inlet section. This ensures that the heated secondary gas flows close to the catalytic converter.

[0013] Multiple inflow elements can also be installed at different locations upstream of the corresponding catalytic converter housing. These multiple inflow elements can be arranged axially or distributed circumferentially around the corresponding exhaust gas conduction element of the exhaust gas subsystem.

[0014] Furthermore, it is advantageous for all inflow openings to include the same opening cross-section, or for at least a first portion of 30% to 70% of the inflow openings to include an opening cross-section greater than that of a second portion of the inflow openings. The inflow openings can be orifices or recesses, wherein specifically, orifices can have circular or elliptical opening cross-sections. The inflow openings may be free of blades or guide elements. By varying the opening cross-section, the flow path of the hot gas generated during mixing or the distribution of said hot gas in the exhaust gas can be optimized. Multiple inflow openings form perforations having a perforation pattern further defined below by way of example.

[0015] It is also advantageous that the inlet section includes several recesses, each containing at least one inflow opening. One or more inflow openings preferably extend in the circumferential direction U (i.e., circumferential). The available collection space can be increased by forming the recesses. Clogged pores due to deposits of soot or particles can impair the function of the pores and thus the exhaust gas subsystem. The recesses prevent pore clogging. It is also advantageous that the opening axes of adjacent inflow openings and / or the opening axes within the recesses are inclined or arranged relative to each other at an angle α. By using the angle of attack / incident angle, the flow path of the hot gas generated during mixing or the distribution of said hot gas in the exhaust gas can be optimized. The resulting angular plane can be radially aligned with the main exhaust gas flow axis. Angle α > 0, and angle α can depend on the cross-sectional shape of the recess. In this sense, the inflow openings do not contain guiding elements.

[0016] For the present invention, it may be particularly important that the angle α satisfies the following conditions: 20° <= α <= 170° or 70° <= α <= 90°. This range of angles can ensure optimal inflow of hot gas, depending on existing flow conditions or the load conditions of interest in the exhaust gas stream. In this respect, the secondary gas mixes particularly well with the exhaust gas stream.

[0017] In conjunction with the design and arrangement according to the invention, it is advantageous for the opening axes of adjacent inflow openings and / or the opening axes within the recesses to be inclined or arranged towards the main exhaust gas flow axis at different angles γ1, γ2, where 70° <= γ1 <= 90° and 20° <= γ2 <= 40°. Using such an angle range, optimal inflow of hot air can be ensured based on existing flow conditions or the load conditions of interest in the exhaust gas flow. This optimizes the mixing of secondary gas and exhaust gas flow. The main exhaust gas flow axis corresponds to the central axis of the catalytic converter housing element or to the central axis of the inlet section. The direction of the hot gas flow to be mixed can also have a directional component opposite to that of the exhaust gas flow.

[0018] It is also advantageous to provide at least two rows of inlet openings and / or two rows of recesses, each recess having at least one inlet opening, wherein the rows extend in the circumferential direction U relative to the main exhaust gas flow axis and are arranged adjacent to each other. This allows hot gas to be introduced into at least two stages via the first row and at least the second row. The fact that at least the first portion of 30% to 70% of the inlet openings has an opening cross-section larger than that of the other portions of the inlet openings also applies relative to the rows. Inlet openings in one row or inlet openings in different rows or adjacent rows can therefore have different opening cross-sections. This measure also improves the mixing of secondary gas and exhaust gas flow.

[0019] It is also advantageous that, within at least one row, the angle α between the two inflow openings is different, or the angle γ1 or angle γ2 is different. The angle α between the two inflow openings and / or the angles γ1 and γ2 within one row can also be the same.

[0020] It is also advantageous that the angle α and / or angles γ1 and γ2 are different between adjacent rows. The angle α between two inflow openings and / or the angles γ1 and γ2 of adjacent rows can also be the same.

[0021] Advantageously, the inflow element encloses the inlet section in the circumferential direction U with an angle β relative to the axis of the main exhaust gas flow, where 50° <= β <= 360°. The enclosure angle β should not be less than a minimum value in order to achieve a regular or uniform inflow of hot gas. Therefore, the angle β also limits the circumferential range of the opening or recess in the corresponding row.

[0022] It is also advantageous to use electric heating elements or to heat the secondary gas via a combustion chamber or combustion chamber of the heating element. Electric heating converts electrical energy into heat energy. In this way, the secondary gas is heated. Fuel is burned inside the combustion chamber. This generates heat for heating the secondary gas. Both methods are efficient and allow for active, independent, and external operation of the heating element.

[0023] It is also advantageous to include a control unit for actively controlling the heating element in order to adjust the temperature and / or mass flow of the heated secondary gas. This allows for active control or regulation of the heating element. Attached Figure Description

[0024] Further advantages and details of the invention are set forth in the claims and description, and are illustrated in the drawings. The drawings show:

[0025] Figure 1 It is a schematic diagram of the exhaust gas subsystem; Figure 2a It is a schematic diagram of an inlet section with an inflow opening; Figure 2b It is Figure 2a Another embodiment; Figure 3 It is a schematic diagram of the entrance section as seen from the front; Figure 4 It is a schematic diagram of a motor vehicle exhaust system. Detailed Implementation

[0026] Figure 1 The exhaust gas subsystem 1 shown is Figure 4 Part of the integrated exhaust gas system 4 shown, such as Figure 4 As shown, the integrated exhaust system 4 is used to completely clean and reprocess the main exhaust gas flow 4.3 or the main exhaust gas flow from the internal combustion engine 4.6. Downstream of the exhaust subsystem 1, which is further described below, the exhaust system 4 also includes a catalytic converter housing 2 and a particulate filter 4.1, and further downstream includes an exhaust muffler 4.2. The catalytic converter housing 2 has an exhaust catalytic converter, which is not shown in further detail. The exhaust subsystem 1 is connected to the mains 4.5 of the internal combustion engine 4.6. The corresponding components are flow-coupled to each other via the exhaust pipe 4.4.

[0027] The exhaust gas subsystem 1 includes an inlet section 3 for exhaust gas delivery, which is connected upstream of the catalytic converter housing 2 to supply exhaust gas. Opposite to the catalytic converter housing 2, the exhaust gas stream 4.3 from the internal combustion engine 4.6 is delivered to the inlet section 3 via an exhaust pipe (not shown in further detail). The exhaust gas entering upstream of the inlet section 3 is delivered to the catalytic converter housing 2 via the inlet section 3. The inlet section 3 has a generally conical shape such that its flow cross-section increases from the inlet opening 3.2 to the catalytic converter housing 2.

[0028] Inlet section 3 is connected to inflow element 5.1, such as... Figure 1 As shown, the inflow element is designed as a semi-shell channel, such as Figure 3 As shown, the semi-shell channel is positioned on the outer side 3.4 of the inlet section 3 in the circumferential direction U. The outer side 3.4 of the inlet section 3 or its outer shell wall 3.3, together with the inflow element 5.1, forms a collection chamber 5.4, which is supplied with heated secondary gas 5.3 via a supply line 5 and a heating element connected upstream of the supply line. The heated secondary gas 5.3 flows into the inlet section 3 via the collection chamber 5.4 and corresponding inflow openings 5.2 within the inlet section 3 or within the outer shell wall 3.3 of the inlet section 3, and mixes with or is mixed into the waste gas flow 4.3 in the inlet section 3. The outer shell wall 3.3 includes a plurality of inflow openings 5.2. Figure 2a The inflow openings 5.2 are each arranged as orifices and distributed either within the circumference of the inlet section 3 or along the circumferential direction U. The cross-section Q of the opening is circular. Alternatively, it may be elliptical. Since no flow guiding element is provided at the inflow opening 5.2, the cross-section Q of the opening does not contain a guiding element. Figure 2a The system has two inflow openings, 5a and 5b, set up according to... Figure 2b In one embodiment, two rows of recesses 3.1, 3a and 3b, are provided, wherein two inflow openings 5.2 are provided in each recess 3.1 of the outer shell wall 3.3.

[0029] According to Figure 1 In the cross-sectional view of the embodiment, the corresponding recess 3.1 is shown as having two inflow openings 5.2.

[0030] The corresponding inflow opening 5.2 includes an opening axis 5.5 perpendicularly aligned with the surrounding outer casing wall 3.3. According to... Figure 1 In one embodiment, two inflow openings 5.2 are provided in the corresponding recess 3.1, and the opening axis 5.5 of the corresponding recess is set or inclined at an angle α. According to Figure 1 In the lower embodiment, one opening axis is radially aligned with the main exhaust gas flow axis 2.1 and forms an angle γ1 of approximately 90° with the main exhaust gas flow axis 2.1. The other opening axis forms an angle γ2 of approximately 30° with the main exhaust gas flow axis 2.1. This means that a portion of the hot gas is supplied in the radial direction, while another portion of the exhaust gas is supplied with a corresponding axial directional component. Angle γ1 can also be less than 90°. This would have a directional component opposite to the direction of the main exhaust gas.

[0031] The collection chamber 5.4 is supplied via a supply line from an active, separate external heating element 6, which includes a combustion chamber or combustion chamber 6.1. Secondary gas 5.3 flows into said combustion chamber or combustion chamber for heating, and is released into the collection chamber 5.4 during heating, and thus into the inlet section 3. Alternatively, the secondary gas 5.3 may be electrically heated. Furthermore, a control unit 7 is provided, which controls the active heating element 6 and controls the temperature and mass flow of the secondary gas 5.3.

[0032] exist Figure 3 In this embodiment, the inlet section 3 is shown in a front view. The inflow element 5.1 extends at an angle β of approximately 200°. The inflow element 5.1 is also supplied with secondary gas 5.3 via a supply line 5, which is heated in a heating element 6, in this case with ambient air.

[0033] according to Figure 4 The exhaust system 4 of the motor vehicle includes an internal combustion engine 4.6, which includes a main pipe 4.5. Exhaust gas flow 4.3 is guided through an exhaust pipe 4.4 and delivered to an inlet section 3. An inlet element 5.1 is provided at the inlet section 3, through which secondary gas 5.3 heated by a heating element 6 is delivered into the exhaust gas flow 4.3 and mixed with it. Specifically, the heating element 6 is not part of the exhaust system 4 and is therefore considered an external element. Further downstream of the inlet section is a catalytic converter housing 2 having a catalytic converter 2.2, to which a particulate filter 4.1 is connected. An exhaust muffler 4.2 is provided at the end of the exhaust pipe 4.4.

Claims

1. An exhaust gas subsystem (1) for an internal combustion engine (4.6), comprising: The catalytic converter housing (2) has an inlet section (3) and an inlet opening (3.2) for introducing exhaust gas (4.3) into the catalytic converter housing (2), and A supply line (5) for conveying secondary gas (5.3) and not containing waste gas flow, the supply line (5) includes an inflow element (5.1) disposed at its end, through which the secondary gas (5.3) is conveyed to the waste gas flow (4.3). The inflow element (5.1) is located upstream of the catalytic converter housing (2). A heating element (6) for heating the secondary gas (5.3) is provided in the supply line (5) upstream of the inflow element (5.1). The feature is that multiple inflow openings (5.2) at the inlet section (3) are connected to the inflow element (5.1), and the heated secondary gas (5.3) can be transported from the supply pipeline (5) to the waste gas flow (4.3) via the inflow element. The inflow element (5.1) and the outer side (3.4) of the inlet section (3) together define the collection chamber (5.4), and the secondary gas (5.3) enters the inlet section (3) from the collection chamber (5.4) via the inflow opening (5.2), wherein each of the inflow openings (5.2) includes an opening cross-section and an opening axis (5.5). The opening axes (5.5) of adjacent inflow openings (5.2) are inclined at an angle α to each other, forming different incident angles toward the main exhaust gas flow axis (2.1), which corresponds to the central axis of the catalytic converter housing (2) or the central axis of the inlet section (3).

2. The waste gas subsystem (1) according to claim 1, characterized in that, The inflow element (5.1) is disposed at the inlet section (3), and / or the inflow opening (5.2) is disposed in the inlet section (3).

3. The waste gas subsystem (1) according to claim 1, characterized in that, All inflow openings (5.2) include the same opening cross-section, or At least a first portion of the inflow opening (5.2) comprises 30% to 70% of the opening cross-section of a second portion of the inflow opening (5.2) greater than 70% to 30%.

4. The waste gas subsystem (1) according to claim 3, characterized in that, The inlet section (3) includes at least one or more recesses (3.1), each recess (3.1) having at least one inflow opening (5.2).

5. The waste gas subsystem (1) according to claim 4, characterized in that, Each recess (3.1) is provided with two said inflow openings (5.2), and the opening axes (5.5) within the same recess (3.1) are inclined to each other at an angle α.

6. The waste gas subsystem (1) according to claim 5, characterized in that, The angle α satisfies the following conditions: 20° <= α <= 170° or 70° <= α <= 90°.

7. The waste gas subsystem (1) according to claim 4, characterized in that, The opening axis (5.5) of the adjacent inflow opening (5.2) and / or the opening axis (5.5) within the recess (3.1) are inclined toward the main exhaust gas flow axis (2.1) at different angles γ1 and γ2, wherein 70°<= γ1<= 90° and 20°<= γ2<= 40°.

8. The waste gas subsystem (1) according to claim 7, characterized in that, The facility is provided with at least two rows (5a, 5b) of inflow openings (5.2) and / or two rows (3a, 3b) of recesses (3.1), each row and each recess (3.1) including at least one inflow opening (5.2), the rows (3a, 3b, 5a, 5b) being arranged adjacent to each other in the circumferential direction U relative to the main exhaust gas flow axis (2.1).

9. The exhaust gas subsystem (1) according to claim 8, characterized in that, Within at least one row (3a, 3b, 5a, 5b), the angle α between the two inflow openings (5.2) is different and / or the angles γ1 and γ2 are different.

10. The waste gas subsystem (1) according to claim 8, characterized in that, Between adjacent rows (3a, 3b, 5a, 5b), the angle α is different and / or the angles γ1 and γ2 are different.

11. The waste gas subsystem (1) according to claim 8, characterized in that, The inflow element (5.1) encloses the inlet section (3) in the circumferential direction U with an angle β relative to the main exhaust gas flow axis (2.1), where 50° <= β <= 360°.

12. The waste gas subsystem (1) according to claim 1, characterized in that, The secondary gas (5.3) can be electrically heated via the heating element (6) or heated via the combustion chamber (6.1) of the heating element (6).

13. The waste gas subsystem (1) according to claim 1, characterized in that, A control unit (7) is provided for actively controlling the heating element (6), the control unit being used to control the temperature and / or mass flow of the secondary gas (5.3).

14. An exhaust gas system (4) comprising an exhaust gas subsystem (1) according to any one of the preceding claims.

15. A method for operating the exhaust gas system (4) according to claim 14, characterized in that, The secondary gas (5.3) is heated by the heating element to regulate the temperature of the catalytic converter (2.2).

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