Heating device for exhaust system of internal combustion engine
The heating device for internal combustion engines addresses incomplete fuel combustion by using a combustion chamber with tangential air-fuel mixing and vortex motion, ensuring complete combustion and stable temperature control, thus enhancing the efficiency and economy of the exhaust system heating process.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- マレリヨーロッパエッセピア
- Filing Date
- 2021-12-22
- Publication Date
- 2026-06-23
AI Technical Summary
Existing heating devices for exhaust systems of internal combustion engines often result in incomplete fuel combustion, leading to unburned fuel entering the exhaust duct and causing sudden, unwanted temperature rises, which is inefficient and potentially damaging.
A heating device with a combustion chamber, fuel injector, and spark plug, designed to ensure complete fuel combustion by mixing air and fuel tangentially and using a static mixer to create vortex motion, along with a check valve to prevent backflow, and a control unit for efficient operation.
Ensures complete fuel combustion, preventing unburned fuel from entering the exhaust duct, maintaining stable temperature, and facilitating rapid heating of the catalytic converter while being economical and easy to manufacture.
Smart Images
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Abstract
Description
Technical Field
[0001] Cross - reference to related applications This patent application claims priority from Italian Patent Application No. 102021000001880 filed on January 29, 2021, the entire disclosure of which is incorporated herein by reference.
[0002] The present invention relates to a heating device for an exhaust system of an internal combustion engine.
Background Art
[0003] The exhaust system of an internal combustion engine includes an exhaust duct along which at least one device for the treatment of exhaust gases coming from the internal combustion engine is installed. In particular, there is always a catalytic converter (either an oxidation catalytic converter or a reduction catalytic converter), and a particulate filter can be added thereto. Chemical reactions for converting unburned hydrocarbons, nitrogen oxides and carbon monoxide into carbon dioxide, water and nitrogen occur only when the operating temperature is reached. Therefore, the catalytic converter needs to operate at a relatively high operating temperature (modern catalytic converters operate at temperatures close to 800 °C) in order to operate (i.e., to perform catalytic conversion).
[0004] During the cold start phase (i.e., when the internal combustion engine has been off for a long time and then turns on after the temperature of different parts of the internal combustion engine has reached ambient temperature), the temperature of the catalytic converter remains significantly below the operating temperature for a relatively long time (in winter and during urban driving when the internal combustion engine is idling or operating very slowly, it can be several minutes). As a result, during the cold start phase, i.e., during the time when the catalytic converter has not yet reached its operating temperature, the purification effect of the catalytic converter is close to zero or, in any case, hardly effective, so the amount of polluted exhaust is very high.
[0005] To expedite the arrival of the catalytic converter's operating temperature, Patent Documents 1, 2, 3, 4, 5, and 6 propose installing a heating device along the exhaust duct, which generates a (very) hot airflow by burning fuel, which flows through the catalytic converter. In particular, the heating device includes a combustion chamber, which at the outlet is connected to the exhaust duct (just upstream of the catalytic converter) and at the inlet is connected to a fan, which generates an airflow that flows through the combustion chamber, and which also includes a fuel injector for injecting fuel to be mixed with air, and a spark plug for periodically generating a spark to ignite the air-fuel mixture to obtain combustion that heats the air.
[0006] In known heating devices, fuel combustion is not always complete under all operating conditions, and therefore, unburned fuel can reach the exhaust duct and burn inside the exhaust duct (especially when large amounts of fuel are injected to generate a large amount of heat), thus causing a sudden, unexpected, and unwanted temperature rise locally. [Prior art documents] [Patent Documents]
[0007] [Patent Document 1] European Patent Application Publication No. 0631039 [Patent Document 2] International Publication No. 2012139801 brochure [Patent Document 3] U.S. Patent No. 8006487 [Patent Document 4] U.S. Patent Application Publication No. 2011289906 [Patent Document 5] European Patent Application Publication No. 0590699 [Patent Document 6] Japanese Patent Publication No. 2005-180371 [Overview of the project] [Problems that the invention aims to solve]
[0008] The object of the present invention is to provide a heating device for the exhaust system of an internal combustion engine, which enables complete fuel combustion (i.e., prevents unburned fuel from being introduced into the exhaust duct) and is also easy and economical to manufacture. [Means for solving the problem]
[0009] According to the present invention, a heating device for an exhaust system of an internal combustion engine is provided according to the appended claims.
[0010] The attached claims describe preferred embodiments of the present invention and form an integral part of this description.
[0011] The present invention will now be described with reference to the accompanying drawings, which illustrate some non-limiting embodiments thereof. [Brief explanation of the drawing]
[0012] [Figure 1] This is a schematic, partial diagram of the exhaust system of an internal combustion engine equipped with a heating device according to the present invention. [Figure 2] Figure 1 is a schematic longitudinal cross-sectional view of the heating device, with components removed for greater clarity. [Figure 3] This is a more detailed, enlarged view of Figure 2. [Figure 4] This is a more enlarged, detailed view of Figure 2, showing a different embodiment. [Figure 5] Figure 1 is a schematic diagram of an alternative embodiment of fuel injection generated by the fuel injector of the heating device. [Figure 6] Figure 1 is a schematic diagram of an alternative embodiment of fuel injection generated by the fuel injector of the heating device. [Figure 7] Figure 1 is a schematic diagram of the spark plug of the heating device. [Figure 8]Schematic diagram of the spark plug electrodes of FIG. 7, emphasizing the possible directions of fuel injection released by the fuel injector. [Figure 9] Schematic diagram of an alternative embodiment of the spark plug electrodes of FIG. 7, emphasizing the possible directions of fuel injection released by the fuel injector. [Figure 10] Schematic diagram of an alternative embodiment of the spark plug electrodes of FIG. 7, emphasizing the possible directions of fuel injection released by the fuel injector. [Figure 11] A more enlarged view of the details of FIG. 2 according to a further embodiment.
Embodiments for Carrying Out the Invention
[0013] In FIG. 1, number 1 indicates the exhaust system of internal combustion engine 2 as a whole.
[0014] The exhaust system 1 includes an exhaust duct 3, which starts from the exhaust manifold of the internal combustion engine 2 and ends at the muffler 4, from where the exhaust gas is released into the atmosphere. At least one device 5 for treating the exhaust gas coming from the internal combustion engine is installed along the exhaust duct 3. In particular, there is always a catalytic converter (either an oxidation catalytic converter or a reduction catalytic converter), and a particulate filter can be added to this. Since the chemical reactions for converting unburned hydrocarbons, nitrogen oxides, and carbon monoxide into carbon dioxide, water, and nitrogen only occur when the operating temperature is reached, the catalytic converter needs to operate at a relatively high operating temperature in order to operate (i.e., to perform catalytic conversion) (modern catalytic converters operate at temperatures close to 800 °C).
[0015] To accelerate the heating of the treatment device 5, i.e., to enable the treatment device 5 to reach its operating temperature more quickly, the exhaust system 1 includes a heating device 6, which generates a (very) hot air flow by burning fuel, and this flows through the treatment device 5.
[0016] The heating device 6 includes a combustion chamber 7, which at its outlet is connected to an exhaust duct 3 (just upstream of the treatment device 5), and at its inlet is connected to a fan 8 (i.e., an air pump) which generates an airflow that flows through the combustion chamber 7. In the combustion chamber 7, there is also a fuel injector 9 that injects fuel to be mixed with air, and a spark plug 10 that periodically generates a spark to ignite the air-fuel mixture to obtain combustion that heats the air. The combustion chamber 7 of the heating device 6 ends at an outlet duct 11, which leads into the exhaust duct 3 (just upstream of the treatment device 5).
[0017] As shown in Figure 2, the heating device 6 includes a tubular body 12 (for example, cylindrical, and having a circular or elliptical cross-section) having a longitudinal axis 13, the tubular body 12 being limited at two ends by two opposing base walls 14 and 15 and laterally limited by a side wall 16, which connects the two base walls 14 and 15 to each other. The base wall 14 is perforated in the center to accommodate a fuel injector 9, which is mounted coaxially with the tubular body 12 (i.e., coaxially with the longitudinal axis 13), in other words, the fuel injector 9 is mounted through the base wall 14 of the tubular body 12 to inject fuel into the combustion chamber 7.
[0018] Similarly, the base wall 15 has a hole in its center to fit the outlet duct 11, which ends in the exhaust duct 3, meaning the base wall 15 has an outlet opening 17 for releasing hot air from the combustion chamber 7 where the outlet duct 11 begins.
[0019] As shown in Figure 2, at least a portion of the inlet opening 18 is obtained through the tubular body 12, which is connected to the fan 8 by means of an inlet duct 19 (shown in Figure 1) to receive an airflow directed toward the combustion chamber 7 and mixed with the fuel injected by the fuel injector 9. Preferably, the air flows into the inlet opening 18 in a flow oriented tangentially (relative to the tubular body 12), i.e., the inlet duct 19 is oriented tangentially (relative to the tubular body 12).
[0020] According to a possible, but unrestrained, embodiment shown in Figure 1, a check valve 20 is present in the region of the inlet opening 18, which allows only airflow toward the combustion chamber 7 (i.e., into the tubular body 12). Preferably, the check valve 20 is passive (i.e., does not involve an electric, hydraulic, or pneumatic actuator that generates motion), pressure-controlled, and opens only when the pressure upstream of the check valve 20 is higher than the pressure downstream of the check valve 20. The function of the check valve 20 is to prevent exhaust gas from flowing backward until it exits the inlet opening 18 and thus being released into the atmosphere without passing through the treatment device 5 when the heating device 6 is not in use (i.e., when the fan 8 is off). Alternatively, the check valve 20 can be mounted along the outlet duct 11, for example, in the area of the outlet opening 17. In this case, the check valve 20 allows only air to flow out from the combustion chamber 7 (from the tubular body 12) toward the exhaust duct 3, that is, it prevents exhaust gas from flowing from the exhaust duct 3 toward the combustion chamber 7 (into the tubular body 12).
[0021] As shown in Figure 2, the heating device 6 includes a supply channel 21 which receives air from an inlet opening 18 and terminates with a nozzle 22 surrounding the end of the fuel injector 9, which is positioned around the injection point of the fuel injector 9 (i.e., around the spray tip of the fuel injector 9 from which the fuel flows out).
[0022] The spark plug 10 is mounted through the side wall 16 of the tubular body 12 to cause combustion of the air-fuel mixture, which is obtained by mixing air that flows into the tubular body 12 from the inlet opening 18 and is introduced into the combustion chamber 7 by the nozzle 22 of the supply channel 21 with fuel injected into the combustion chamber 7 by the fuel injector 9. In particular, the side wall 16 of the tubular body 12 has a through hole which is oriented radially (i.e., perpendicular to the longitudinal axis 13) and houses the spark plug 10 (which is obviously oriented radially) inside (screwed into it).
[0023] The heating device 6 includes a static mixer 23 (i.e., without moving parts), which has an annular shape and is positioned around the fuel injector 9 along the supply channel 21 and is configured to generate turbulence, in particular vortex motion, in the air flowing toward the nozzle 22.
[0024] According to the preferred, but unconstrained, embodiment shown in the attached figure, downstream of the static mixer 23, the supply channel 21 has a progressive decrease in cross-sectional area to determine the increase in air velocity. Specifically, downstream of the static mixer 23, the supply channel 21 has an introductory section with a constant cross-sectional area, an intermediate section with a gradually decreasing cross-sectional area, and an end section with a constant cross-sectional area up to the nozzle 22.
[0025] The supply channel 21 is defined on the outside by an outer tubular body 24 (at least partially conical) and on the inside by an inner tubular body 25 (at least partially conical), which surrounds the fuel injector 9 and houses the fuel injector 9 (i.e., acts as a container for the end of the fuel injector 9). In other words, the supply channel 21 is defined between the inner tubular body 25 and the outer tubular body 24. In particular, the two tubular bodies 24 and 25 alternate between conical portions (i.e., having a converging shape that gradually decreases in size) and cylindrical portions (i.e., having a shape of constant size), preferably the end of the inner tubular body 25 has a converging taper (i.e., this gradually decreases in size toward the nozzle 22), while the end of the outer tubular body 24 has a cylindrical shape.
[0026] According to one preferred embodiment, air flows into the supply channel 21 in a tangentially oriented flow that has vortex motion (subsequently increased by the action of the static mixer 23) which helps to mix with the fuel injected by the fuel injector 9, in other words, by introducing oxidizing air into the combustion chamber 7 through a duct tangentially oriented to the combustion chamber 7, the oxidizing air flow can obtain circular motion (further enhanced by the presence of the static mixer 23) to optimize the mixing of air and fuel inside the combustion chamber 7.
[0027] As shown in Figure 3, the fuel injector 9 is configured to spray at least 80% (preferably at least 90-95%) of the fuel against the inner surface 26 of the supply channel 21. That is, rather than directing the fuel directly outward from the supply channel 21, the fuel injector 9 directs the fuel against the inner surface 26 of the supply channel 21, so that the fuel flowing out of the fuel injector 9 strikes the inner surface 26 before flowing out of the supply channel 21 through the nozzle 22. The impact of the fuel against the inner surface 26 allows the droplets of fuel released by the fuel injector 9 to be broken down in a very effective manner, thereby significantly improving the mixing of the fuel with the air flowing along the supply channel 21. This improved mixing of air and fuel ensures ideal, and in particular, complete combustion of the fuel, and thus prevents any unburned fuel from flowing out of the combustion chamber 7.
[0028] According to one preferred embodiment, the fuel injector 9 is configured to discharge a fuel injection 27 having a centrally hollow cone shape, i.e., an annular cross-section, so that the fuel accumulates around the periphery. In particular, according to the embodiment shown in Figure 3, the outer surface of the fuel injection 27 has an opening angle α of about 70° (for example, in the range between 65° and 75°), and the inner surface of the fuel injection 27 has an opening angle β of about 50° (for example, in the range between 45° and 55°). In other words, the fuel injector 9 produces a fuel injection 27 having a cone shape (the apex of the cone is close to the injection nozzle) and a centrally cone-shaped hole (i.e., a region without fuel), so that the fuel injection 27 produced by the fuel injector 9 has a cone shell shape due to the presence of the central hole, i.e., a hollow cone shape inside.
[0029] When we say that the fuel injection 27 produced by the fuel injector 9 has a conical shell shape (i.e., a hollow cone shape inside), it means that most of the fuel flowing out of the fuel injector 9 spreads within the space of the conical shell, but it should be noted that a very small portion of the fuel (the remaining portion) may spread differently. Furthermore, depending on how the fuel outlet opening is constructed, the fuel injection 27 flowing out of the fuel injector 9 can have a more symmetrical distribution around the longitudinal axis 13 (as shown in Figure 5) or a more asymmetrical distribution around the longitudinal axis 13 (as shown in Figure 6). In particular, when the fuel injector 9 is of the "spiral" type, the fuel injection 27 flowing out of the fuel injector 9 has the configuration shown in Figure 5, whereas when the fuel injector 9 is of the "porous" type, the fuel injection 27 flowing out of the fuel injector 9 has the configuration shown in Figure 6 (Figure 6 shows a "porous" fuel injector 9 with six outlet holes, but the number of outlet holes may vary).
[0030] In one preferred embodiment, the fuel injector 9 is of the "vortex" type, that is, it imparts rotational vortex motion to the injected fuel (i.e., vortex motion in which the fuel rotates around the longitudinal axis 13 of the tubular body 12).
[0031] As described above, the supply channel 21 is confined on the outside by an outer tubular body 24 (having an inner surface 26 of the supply channel 21), and confined on the inside by an inner tubular body 25, which surrounds the fuel injector 9 and houses the fuel injector 9.
[0032] According to Figure 3, the outer tubular body 24 includes a conical portion 28, which decreases in size toward the nozzle 22. Furthermore, according to one preferred embodiment shown in the accompanying figures, the outer tubular body 24 also includes a cylindrical portion 29, which is located downstream of the conical portion 28 and terminates at the nozzle 22. According to one different embodiment not shown herein, the outer tubular body 24 does not have a cylindrical portion 29 and therefore includes only the conical portion 28. According to one further embodiment not shown herein, the cylindrical portion 29 may also be replaced by a further conical portion having a smaller taper (convergence) than the taper (convergence) of the conical portion 28.
[0033] In the embodiment shown in the attached figure, the fuel injector 9 is configured to spray at least a portion of the fuel onto the cylindrical portion 29 (or further conical portion) of the outer tubular body 24, and in particular, the fuel injector 9 is configured to spray most (almost all) of the fuel onto the cylindrical portion 29 (or further conical portion) of the outer tubular body 24. According to a different embodiment, the fuel injector 9 is configured to spray at least a portion of the fuel onto the cylindrical portion 29 (or further conical portion) of the outer tubular body 24, and at least a portion of the fuel onto the conical portion 28 of the outer tubular body 24, for example, the fuel injector 9 is configured to spray about half of the fuel onto the conical portion 28 of the outer tubular body 24, and about half of the fuel onto the cylindrical portion 29 (or further conical portion) of the outer tubular body 24. In a further embodiment, the fuel injector 9 is configured to spray at least a portion of the fuel onto the conical portion 28 of the outer tubular body 24, and in particular, the fuel injector 9 is configured to spray most (almost all) of the fuel onto the conical portion 28 of the outer tubular body 24.
[0034] As shown in Figure 2, the axial distance X between the spray tip of the fuel injector 9 from which the fuel flows out (i.e., the injection point of the fuel injector 9) and the longitudinal axis 30 of the spark plug 10 (i.e., measured along the longitudinal axis 13 of the tubular body 12) is in the range of 33% to 100% of the inner diameter D of the tubular body 12 (i.e., the diameter D of the combustion chamber 7), preferably in the range of 50% to 100% of the inner diameter D of the tubular body 12, and in particular in the range of 60% to 90% of the inner diameter D of the tubular body 12. The tubular body 12 preferably has a circular cross-section, and therefore there is no doubt as to how the inner diameter D of the tubular body 12 must be measured to assess the axial distance X. On the contrary, if the tubular body 12 has an elliptical cross-section, it should be noted that the larger size should be taken into consideration as the diameter D of the tubular body 12 to assess the axial distance X.
[0035] According to Figures 7 and 8, the spark plug 10 has only one inner electrode 31 and only one outer electrode 32; according to the variations shown in Figures 9 and 10, the spark plug 10 has only one inner electrode 31 and two outer electrodes 32 (Figure 9), or one inner electrode 31 and four outer electrodes 32 (Figure 10); according to a further variation not shown herein, there may also be three outer electrodes 32.
[0036] As shown in Figure 4, the outer tubular body 24 has a through-opening 33 (i.e., a slit) through which the spray tip of the fuel injector 9 (i.e., the injection point of the fuel injector 9) from which the fuel flows out directly targets the electrodes 31 and 32 of the spark plug 10. Thanks to the presence of the through-opening 33, a limited portion 34 of the fuel injection 27 released by the fuel injector 9 does not hit the outer tubular body 24 but passes through the outer tubular body 24 until it directly reaches the electrodes 31 and 32 of the spark plug 10. In other words, thanks to the presence of the through-opening 33, a limited portion 34 of the fuel injection 27 directly "wets" the electrodes 31 and 32 of the spark plug 10, creating a localized fuel excess (i.e., a locally richer mixture) around the electrodes 31 and 32 of the spark plug 10, which helps ignite the flame and thus facilitates faster propagation of the flame to the rest of the mixture.
[0037] According to Figure 4, the through-opening 33 is formed like a slit, that is, it has a circumferential size that is larger than its axial size, and preferably the circumferential side of the through-opening 33 is in the range of 30° to 60° angularly.
[0038] As shown in Figures 8, 9, and 10, the outer electrode 32 (or multiple outer electrodes 32) of the spark plug 10 is oriented so as not to obstruct (block) the limited portion 34 of the fuel injection 27 moving toward the inner electrode 31; that is, the outer electrode 32 (or multiple outer electrodes 32) of the spark plug 10 is oriented so as not to cover (block) the inner electrode 31 from the limited portion 34 of the fuel injection 27. As a result, the spark generated between the two electrodes 31 and 32 is not obstructed (blocked) by the outer electrode 32 toward the limited portion 34 of the fuel injection 27. Figures 8 and 9 show both portions 34 of the fuel injection 27 that have the correct orientation toward the electrode 32 (i.e., they are not obstructed by the electrode 32) and portions 34 of the fuel injection 27 that have the wrong orientation toward the electrode 32 (i.e., they are obstructed by the electrode 32), and for this reason are "canceled" by means of "X".
[0039] In the embodiments shown in Figures 3 and 4, the fuel injection 27 discharged by the fuel injector 9 is perfectly symmetrical with respect to the longitudinal axis 13 of the tubular body 12 (and of the fuel injector 9), i.e., the longitudinal axis 13 of the tubular body 12 coincides with the central axis of symmetry 35 of the fuel injection 27. On the other hand, in the embodiment shown in Figure 11, the fuel injection 27 discharged by the fuel injector 9 is asymmetrical with respect to the longitudinal axis 13 of the tubular body 12 (and of the fuel injector 9), and therefore the fuel injection 27 is inclined toward the electrodes 31 and 32 of the spark plug 10, i.e., the central axis of symmetry 35 of the fuel injection 27 forms an angle γ (other than zero) with respect to the longitudinal axis 13 of the tubular body 12. According to one preferred embodiment, the central axis of symmetry 35 of the fuel injection 27 is inclined toward the electrodes 31 and 32 of the spark plug 10 such that it forms an angle γ with the longitudinal axis 13 of the tubular body 12, having a width in the range of 5° to 20°, preferably about 13 to 15°. By inclining the fuel injection 27 toward the electrodes 31 and 32 of the spark plug 10, a localized fuel excess (i.e., a locally richer mixture) is generated around the electrodes 31 and 32 of the spark plug 10, which helps ignite the flame and thus facilitates faster propagation of the flame to the rest of the mixture.
[0040] According to one preferred embodiment, the heating device 6 includes a control unit 36 (Schematically shown in Figure 1) which is configured to control the entire operation of the heating device 6, i.e., to coordinate the control of the fan 8, injector 9 and spark plug 10, so as efficiently and effectively as possible to achieve the desired objective (i.e., to rapidly heat the processing device 5 without damaging the processing device 5 due to overheating).
[0041] According to one possible embodiment shown in Figure 1, the heating device 6 includes a temperature sensor 37, which is positioned along the outlet duct 11 to measure the temperature of the hot air flowing through the outlet duct 11, or the heating device 6 includes a temperature sensor 38, which is positioned along the exhaust duct 3 downstream of the point where the outlet duct 11 branches (and upstream of the processing device 5) to measure the temperature of the mixture of exhaust gas and hot air flowing through the exhaust duct 3. Although both temperature sensors 37 and 38 may be present in special applications, generally there is only one of the two temperature sensors 37 and 38. To control combustion in the combustion chamber 7 to rapidly heat the processing device 5 without damaging the processing device 5 due to overheating (by means of feedback control, if necessary), the control device 36 uses the readings of the temperature sensor 37 or 38.
[0042] For this reason, the embodiments described herein can be combined with one another without exceeding the scope of protection of the invention.
[0043] The heating device 6 described above has many advantages.
[0044] First, thanks to the heating device 6 described above, complete fuel combustion (i.e., no unburned fuel is introduced into the exhaust duct 3) is ensured under all operating conditions (especially when a large amount of fuel is injected to generate a large amount of heat), thanks to the ideal mixture between the oxidizing air introduced by the nozzle 22 of the supply channel 21 and the fuel injected by the fuel injector 9.
[0045] Furthermore, the aforementioned heating device 6 has high heating power relative to its overall dimensions; that is, even though it is relatively small, the aforementioned heating device 6 generates high heating power.
[0046] Finally, the heating device 6 described above is easy and economical to manufacture because it consists of a small number of parts with simple shapes that are easily joined by standard welding and joining. [Explanation of symbols]
[0047] 1. Exhaust System 2 Internal Combustion Engine 3. Exhaust duct 4 Silencer 5 Processing Unit 6 Heating device 7 Combustion chamber 8 Fans 9. Fuel Injector 10 Spark plugs 11 Outlet duct 12 Tubular body 13 Long axis 14 Base wall 15 Base wall 16 side wall 17 Exit opening 18 Entrance opening 19 Inlet duct 20 Check valve 21 Supply Channels 22 nozzles 23 Static Mixer 24 Outer tubular body 25 Inner tubular body 26 Inner self 27 Fuel injection 28 Cone section 29 Cylindrical section 30 Long axis 31 Inner electrode 32 Outer electrode 33 Through-opening 34 parts 35 Axis of Symmetry 36 Control Unit 37 Temperature Sensor 38 Temperature Sensor α angle β angle γ angle X distance D diameter
Claims
1. A heating device (6) for the exhaust system (1) of an internal combustion engine (2), wherein the heating device (6) is A tubular body (12) is formed on the inside of the combustion chamber (7), A fuel injector (9) is mounted through the base wall (14) of the tubular body (12) to inject fuel into the combustion chamber (7), At least one inlet opening (18) is directed toward the combustion chamber (7) and can be connected to a fan (8) to receive an airflow that is mixed with the fuel, A supply channel (21) that receives air from the inlet opening (18), surrounds the end of the fuel injector (9), and ends with a nozzle (22) positioned around the injection point of the fuel injector (9), A spark plug (10) having electrodes (31, 32) is mounted through the side wall (16) of the tubular body (12) to cause combustion of a mixture of air and fuel, Includes, The supply channel (21) is partitioned on the outside by an outer tubular body (24) having an inner surface (26) of the supply channel (21), and partitioned on the inside by an inner tubular body (25), the inner tubular body (25) surrounds the fuel injector (9) and houses the fuel injector (9) on the inside, The heating device (6) is The fuel injector (9) is configured to spray at least a portion of the fuel onto the outer tubular body (24), The outer tubular body (24) has a through-opening (33), and through this, the spray tip of the fuel injector (9) that dispenses the fuel directly targets the electrodes (31, 32) of the spark plug (10). Heating device (6).
2. The heating device (6) according to claim 1, wherein, during use, a limited portion (34) of the fuel injection (27) released by the fuel injector (9) through the through-opening (33) passes through the outer tubular body (24) without hitting the outer tubular body (24) and reaches the electrodes (31, 32) of the spark plug (10) directly.
3. The heating device (6) according to claim 1 or 2, wherein the through-opening (33) is formed like a slit and has a circumferential size that is larger than its axial size.
4. The heating device (6) according to claim 1, 2, or 3, wherein the through-opening (33) has a circumferential size in the range of 30° to 60°.
5. The spark plug (10) has an inner electrode (31) and at least one outer electrode (32), The outer electrode (32) is oriented so as not to block a limited portion (34) of the fuel injection (27) moving toward the inner electrode (31). A heating device (6) according to any one of claims 1 to 4.
6. The spark plug (10) has an inner electrode (31) and at least one outer electrode (32), The outer electrode (32) is oriented so as not to obstruct the inner electrode (31) from a limited portion (34) of the fuel injection (27). A heating device (6) according to any one of claims 1 to 4.
7. The heating device (6) according to any one of claims 1 to 6, wherein the fuel injector (9) is configured to discharge a fuel injection (27) having a centrally hollow conical shape, i.e., an annular cross-section.
8. The heating device (6) according to claim 7, wherein the outer surface of the fuel injection (27) has an opening angle (α) of approximately 70°, and the inner surface of the fuel injection (27) has an opening angle (β) of approximately 50°.
9. The heating device (6) according to any one of claims 1 to 8, wherein the fuel injection (27) discharged by the fuel injector (9) is asymmetrical with respect to the longitudinal axis (13) of the tubular body (12), and the fuel injection (27) is inclined toward the electrodes (31, 32) of the spark plug (10).
10. The heating device (6) according to claim 9, wherein the central axis of symmetry (35) of the fuel injection (27) forms a non-zero angle (γ) with the longitudinal axis (13) of the tubular body (12).
11. The heating device (6) according to claim 10, wherein the angle (γ) between the central axis of symmetry (35) of the fuel injection (27) and the longitudinal axis (13) of the tubular body (12) is in the range of 5° to 20°.
12. The heating device (6) according to any one of claims 1 to 11, wherein the fuel injector is configured to spray at least 80% of the fuel onto the inner surface (26) of the supply channel (21).
13. The heating device (6) according to any one of claims 1 to 12, wherein the fuel injector (9) is of a spiral type and imparts rotational vortex motion to the fuel.
14. A heating device (6) according to any one of claims 1 to 13, comprising a static mixer (23) having an annular shape and positioned around the fuel injector (9) along the supply channel (21) and configured to generate turbulence, in particular vortex motion, in the air flowing toward the nozzle (22).
15. An exhaust system (1) of an internal combustion engine (2), wherein the exhaust system (1) is An exhaust duct (3) begins at the exhaust manifold of the internal combustion engine (2) and ends at a silencer (4) through which the exhaust gas is released into the atmosphere, An exhaust gas treatment device (5) is arranged along the exhaust duct (3), A heating device (6) is connected to the exhaust duct (3) upstream of the exhaust gas treatment device (5) by means of an outlet duct (11) coming from the exhaust duct (3), and is designed to generate a hot airflow by burning fuel, and is manufactured according to any one of claims 1 to 14. Exhaust system (1), including the exhaust system.
16. The heating device (6) is Temperature sensors (37, 38) are arranged along the outlet duct (11) or along the exhaust duct (3) downstream of the point where the outlet duct (11) branches, A control unit (36) adjusts the combustion in the heating device (6) based on the measured values provided by the temperature sensors (37, 38), The exhaust system (1) according to claim 15, including the following: