Intake and exhaust systems for internal combustion engines or combustion units and methods of operating them

Abstract

An intake and exhaust system (1) for an internal combustion engine (100) or thermal combustion unit operating on a fuel based on hydrocarbons or derivatives thereof, comprising a cooling device (4) for cooling water vapor contained in exhaust gases leaving the exhaust section (102) of the internal combustion engine (100) and passing through an exhaust line (2), a recirculation pipeline (10) for fluidly connecting the exhaust line (2) to the intake section (101) of the internal combustion engine (100), and further comprising purification means for removing liquid and / or solid and / or gaseous combustion products contained in the exhaust gases to convert the exhaust gases at the outlet of the exhaust line into a feed gas, a sensor (3) for measuring the oxygen content of the exhaust gases, oxygen injection means (20) for injecting oxygen or an oxygen mixture into the recirculation pipeline (10), and purification means for removing further liquid and / or solid and / or gaseous combustion products contained in the exhaust gases.

Description

[Technical Field]

[0001] The present invention relates to intake and exhaust systems for internal combustion engines or combustion units, and to methods of operating them. Such intake and exhaust systems are particularly suitable for the removal of pollutants in the combustion gases produced by internal combustion engines (ICs), of the diesel or Otto cycle, supercharged or atmospheric, two-stroke and four-stroke type, or by combustion units producing combustion, such as boilers (e.g. LPG, diesel or methane) or coal-fired power plants or other heat-combustion units. [Background technology]

[0002] Currently used exhaust systems downstream of internal combustion engines or thermal combustion units are known to treat and purify exhaust gases produced by endothermic engines or combustion units, or other devices of any size or location that use the combustion of liquid, gaseous, or solid materials, using centrifuges, traps, coolers, afterburners, condensers, catalysts, activated carbon, chemicals, and HEPA filters, although none of these can guarantee the capture and / or transformation into the environment of 100% of the harmful substances present in the gases themselves.

[0003] The use of systems to significantly reduce harmful emissions from internal combustion engines is known. For example, in patent document 1 in the name of the applicant, a cooling device is provided downstream of the exhaust port of an internal combustion engine, which removes water from the exhaust gases by forced thermal shock and condenses it. This water has the advantage of being recycled and atomized upstream of a cyclone, allowing the capture of both a portion of the dust particles, which is properly captured in the condensed water, and gases such as CO and CO2, which are properly captured dissolved in the water produced by condensation of the water vapor contained in the exhaust gases.

[0004] The exhaust gas then passes through a water-air separator, where the exhaust gas and water are completely separated. The separated water can be filtered and reused, or stored in a tank and then disposed of. After passing through the water-air separator, the exhaust gas passes through other filters, such as activated carbon filters or HEPA H14 filters, to remove any particulates that may have slipped through the previous filtration step. Although such solutions are very effective, they cannot completely eliminate NOx gases, which are extremely harmful to people's health.

[0005] Patent Document 2 describes a working gas circulation engine equipped with a combustion chamber. In this engine, an oxidizer (oxygen), a hydrogen-type fuel that generates water vapor when burned together with the oxidizer, and a working gas having a higher specific heat ratio than air are supplied to the combustion chamber. The working gas can expand during fuel combustion, and the engine can discharge the water vapor and working gas as exhaust gas after fuel combustion.

[0006] Such an engine further includes a circulation path and a condensing means. The circulation path circulates the working gas contained in the exhaust gas from the exhaust side to the intake side of the combustion chamber and returns the working gas to the combustion chamber. The condensing means is provided in the circulation path and is capable of condensing water vapor contained in the exhaust gas to convert the water vapor into condensed water. Furthermore, this engine is equipped with a storage means capable of storing condensed water, a pumping means for pumping the condensed water stored in the storage means at a pressure higher than atmospheric pressure, and an evaporation means for evaporating the condensed water by utilizing the waste heat of the exhaust gas, thereby enabling the condensed water to be appropriately treated. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] WO2021 / 198943 [Patent Document 2] WO2010 / 092684 Summary of the Invention [Problem to be solved by the invention]

[0008] It is therefore an object of the present invention to provide an intake and exhaust system for an internal combustion engine or thermal combustion unit, whether fuelled with diesel, synthetic fuel (e-fuel), gasoline or any other fuel based on hydrocarbons and their derivatives, which allows a complete elimination of the harmful substances emitted into the atmosphere by the engine or combustion unit itself.

[0009] A further object of the present invention is to realize an intake and exhaust system that is structurally simple. Yet another object of the present invention is to provide a method of operation that can easily and effectively solve the problem of emissions of harmful substances and gases into the atmosphere in an internal combustion engine or thermal combustion device (such as a boiler or similar device). [Means for solving the problem]

[0010] These and further objects are achieved by an intake and exhaust system for an internal combustion engine or thermal combustion unit operating on a fuel based on a hydrocarbon or its derivatives, preferably a fuel selected from gasoline synthetic fuel (e-fuel), diesel, and LPG. These internal combustion engines or thermal combustion units comprise at least one intake (101) for introducing a feed gas into said internal combustion engine (100) or said thermal combustion unit; at least one exhaust (102) for discharging exhaust gases from the internal combustion engine (100) or the thermal combustion unit; The air supply and exhaust system (1) includes at least one sensor (3) for measuring the oxygen concentration of the exhaust gas discharged from the exhaust section (102), at least one exhaust line (2) fluidly connected to the exhaust section (102), and a cooling device (4) for cooling the exhaust gas discharged from the exhaust section and passing through the exhaust line (2) and condensing water vapor contained in the exhaust gas. The air intake and exhaust system further comprises at least one recirculation pipeline for fluidly connecting the exhaust line to the intake of the internal combustion engine or the thermal combustion unit, and oxygen injection means for injecting oxygen or an oxygen mixture into the recirculation pipeline to convert the exhaust gas into a purified feed gas at the outlet of the exhaust line. The amount of oxygen or oxygen mixture injected is determined depending on the oxygen content of the exhaust gas measured by the at least one sensor for measuring the oxygen content.Furthermore, the exhaust system comprises purification means along the exhaust line for purifying the exhaust gas and removing further liquid and / or solid and / or gaseous combustion products contained in the exhaust gas.

[0011] Such a solution makes it possible to achieve the object of the invention: in fact, thanks to this intake and exhaust system, the internal combustion engine or thermal combustion unit does not produce any emissions into the atmosphere, since the exhaust gases produced by the combustion of only oxygen with a hydrocarbon-based fuel in the appropriate proportions are purified by a purification means to remove the water vapor they contain, then continuously filtered and reintroduced into the internal combustion engine or thermal combustion unit, where they are then enriched with oxygen or an oxygen mixture by injecting a combustion agent.

[0012] The oxygen concentration released into the purified exhaust gas is determined by the concentration detected by a concentration sensor (also called a lambda sensor) located immediately after the exhaust section of the internal combustion engine or thermal combustion unit. Obviously, the intake and exhaust system also serves to reduce the temperature of the exhaust gases at the outlet of the internal combustion engine or thermal combustion unit, and at the same time to reduce their mass by removing the water vapor contained therein. Furthermore, the purification means can remove all unburned solid and liquid particles present in the exhaust gas itself, as well as exhaust gases such as CO2 and CO.

[0013] It is worth noting that when hydrocarbon fuels such as gasoline (as well as diesel, LPG and other similar fuels) are burned, conventional fuels produce water, mainly in the form of steam (H2O), unburned hydrocarbons (HC) and carbon dioxide, whereas synthetic fuels (e-fuels) produce no carbon dioxide, and no unburned solid or gaseous matter. However, the water and carbon dioxide generated by combustion, like the unburned solid or gaseous substances, are recovered by a combination of a cooling and condensing device (cooling device) and a purification means, and purified gas maintaining substantially the same flow rate is supplied to the intake section.

[0014] Although not shown in the examples, the internal combustion engine is also equipped with a fuel injection system for injecting a fuel based on hydrocarbons or their derivatives, which can be injected or directly into the combustion chamber of the engine, where combustion with oxygen can be carried out in a known manner.

[0015] The fuel used in the system according to the invention may be, for example, gasoline, synthetic fuel (e-fuel), diesel, methane, or liquefied petroleum gas. The injection means further comprises at least one injection line, at least one injector arranged along the injection line at least partially in the recirculation circuit, and at least one dosing valve arranged along the injection line upstream of the at least one injector for regulating the amount of oxygen or oxygen mixture injected through the injector. The injector is therefore at least partially positioned in the recirculation line and converts the exhaust gases, fully filtered and freed of water vapor, into gases suitable for supplying to an internal combustion engine or thermal combustion unit as defined above (i.e. selected from a boiler or power plant or the like).

[0016] The system further comprises at least one tank for containing oxygen or an oxygen mixture, the tank being fluidly connected to the infusion line upstream of the dosing valve. In particular, the system further comprises oxygen generating means, which is fluidly connected to the tank upstream of the at least one dosing valve or directly connected to the injection line.

[0017] According to one embodiment of the present invention, said at least one recirculation pipeline is equipped with at least one expansion vessel to allow for expansion or contraction of the purified exhaust gases, in order to maintain as stable a pressure as possible and to prevent excessive pressure which may become a limitation for the engine or combustion unit, or excessive low pressure which may make it difficult for the engine or combustion unit itself to supply and burn new feed gas.

[0018] Additionally, the system includes one or more heater fans positioned along at least one recirculation pipeline to control the flow rate and pressure of the gas circulating in the recirculation pipeline according to demands and needs. Preferably, there are at least two heater fans, one of which is located upstream of the at least one injector and the other of which is located downstream of the at least one injector, and in particular, the rotation speed of the one or more heater fans is controlled according to the flow rate of the supply gas required for normal operation of the engine.

[0019] This allows the flow rate of the supply gas flowing into the intake section to be increased, thereby improving engine power whenever a desired level of supercharging is desired. All of this can be done independently of engine speed, i.e. the system of the present invention is an active regulator of engine filling flow, rather than a passive regulator that is dependent on engine speed, as in the system described in US Pat. No. 5,649,999.

[0020] Furthermore, the system may preferably comprise at least one purified exhaust gas flow meter (also called gas mass meter) located along the recirculation pipeline. The system may further include at least one first sensor for measuring the thermodynamic state of the purified exhaust gas and at least one second sensor disposed along the at least one recirculation pipeline and downstream of the at least one injector for measuring the thermodynamic state of the oxygen-enriched gas, the second sensor disposed along the at least one recirculation pipeline and upstream of the at least one injector.

[0021] Such first and second sensors for measuring the thermodynamic state essentially measure the temperature and / or pressure of the purified gas circulating in the recycle line. In particular, the temperature and pressure of the purified exhaust gas reaching the recirculation pipeline, as well as the temperature and pressure of the feed gas, i.e., the oxygen-enriched purified exhaust gas exiting the exhaust line, are continuously monitored.

[0022] Furthermore, the air supply and exhaust system may include a control unit, which may control the opening and closing of the at least one dosing valve and / or control the operation of the at least one heater fan. In particular, the control unit controls the rotation speed of one or more heater fans depending on the flow rate of the purified exhaust gas measured by a purified exhaust gas flow meter and / or the output of a sensor detecting the oxygen concentration, to ensure the best stoichiometric conditions for combustion. Preferably, the control unit is capable of controlling the opening and closing of at least one dosing valve in response to data from at least one sensor detecting oxygen concentration, to administer a predetermined amount of oxygen through at least one injector.

[0023] More particularly, such a control unit also obtains data from at least one sensor for measuring the thermodynamic state of the gas circulating in the recirculation pipeline, and is also able to operate and control the aforementioned oxygen generating means whenever the gas is present.

[0024] According to a further embodiment of the invention, the purification means comprise, downstream of the cooling device, at least one cyclonic gas / vapor separator and at least one water tank for collecting the water vapor contained in the exhaust gases and condensed separately from the cyclonic gas / vapor separator.

[0025] The purification means preferably further comprises one or more filters arranged along the exhaust line, the filters being arranged downstream of the at least one cyclone separator. The filters are preferably selected from activated carbon filters, HEPA (H14 or higher) filters, carbon dioxide filters, and combinations thereof. These filters capture solid and gaseous contaminants.

[0026] Furthermore, the purification means comprises at least one particle separator (preferably water and / or dry type) along the exhaust line upstream of the cooling device, which particle separator is capable of retaining solid / liquid combustion products, including water and carbonaceous dust.

[0027] Finally, the purification means comprises at least one water injection device for injecting the water in the condensate tank or the water in the storage / reserve container, said water injection device being arranged along the exhaust line upstream of the cyclone separator and / or particle separator. If this water injection device is upstream of the cyclone separator, it is downstream of the cooling and condensing device. When a water injection system is installed upstream of the particle separator, it is also installed upstream of the cooling and condensing unit. Such a water atomizer can capture a large part of the carbon dioxide present in the exhaust gas.

[0028] The object of the present invention is also achieved by a method for operating an intake and exhaust system of an internal combustion engine or a thermal combustion unit according to any one of claims 1 to 16, comprising the following steps: a) supplying a feed gas to an internal combustion engine or thermal combustion unit through an intake; a') supplying an internal combustion engine or thermal combustion unit with a fuel based on hydrocarbons or derivatives thereof, preferably selected from gasoline, diesel, LPG, methane or synthetic fuels (e-fuels, excluding hydrogen), b) measuring the oxygen concentration level detected in the exhaust gas at the outlet of the exhaust at the end of the combustion step of the feed gas and the hydrocarbon or derivative-based fuel inside the internal combustion engine; and c) cooling and condensing exhaust gases emitted from the exhaust of the internal combustion engine or thermal combustion unit to convert them into purified exhaust gases; The method further includes the following steps: d) recirculating the purified exhaust gas discharged from the at least one exhaust line along at least one recirculation pipeline; e) injecting oxygen or an oxygen mixture into the recirculation pipeline in order to convert the purified exhaust gas at the outlet of the exhaust line into the supply gas for the internal combustion engine or the thermal combustion unit, the amount of oxygen injected being determined depending on the oxygen content of the exhaust gas measured in step b); f) filtering the exhaust gas after step c) and before step d) to remove any further liquid and / or solid and / or gaseous combustion products contained in the exhaust gas.

[0029] In step e), oxygen is introduced in an amount to maintain the oxygen concentration of the feed gas at a suitable stoichiometric level, thereby allowing subsequent combustion to occur in an internal combustion engine or in the thermal combustion in an efficient manner. For example, a suitable oxygen level in the purified gas can be greater than 5%. Finally, this method g) measuring the flow rate of exhaust gas passing through the recirculation pipeline; h) increasing or decreasing the rotational speed of the one or more heater fans depending on the flow rate of the purified exhaust gas measured in step g) and / or the oxygen content of the exhaust gas measured in step b). [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a schematic diagram of a supply and exhaust system according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] Some specific embodiments of the present invention will now be described, by way of example only and not by way of limitation, with reference to the accompanying drawings, in which: Figure 1 is a schematic diagram of a supply and exhaust system according to the present invention; With reference to FIG. 1, an intake and exhaust system for an internal combustion engine, or thermal combustion unit, according to the present invention is indicated generally at 1 . In FIG. 1, such an intake and exhaust system 1 is used in an internal combustion engine 100, which has an intake section 101 for introducing supplied gases into the internal combustion engine 100 and an exhaust section 102 for discharging exhaust gases from the internal combustion engine 100. It should be noted that the intake and exhaust system can also be used in internal combustion engines with multiple inlets and multiple exhausts without departing from the scope of protection of the present invention. The internal combustion engine 100 according to the embodiment described herein is of the diesel type, but may also be of the gasoline type or may follow a two-stroke and four-stroke type cycle, either supercharged or atmospheric.

[0032] Such internal combustion engines are equipped in a known manner with a fuel injector that injects hydrocarbon fuels, such as gasoline, synthetic fuels (e-fuel), diesel, LPG, methane, etc. Such internal combustion engines do not run on hydrogen: the supplied gas is mixed with fuel and then appropriately combusted in the combustion chamber of the internal combustion engine. Furthermore, although not shown or described herein, such a supply and exhaust system 1 may also be used in, for example, a boiler-type thermal combustion unit supplied with LPG / methane, or in a coal-fired power plant or other thermal combustion unit.

[0033] The intake and exhaust system 1 includes a sensor 3, also commonly known as a lambda sensor, for measuring the oxygen content or oxygen concentration present in the exhaust gases leaving the exhaust section 102 . Furthermore, the air supply and exhaust system 1 includes an exhaust line 2 fluidly connected to the exhaust section 102, and a cooling device 4 that cools and condenses water vapor contained in the exhaust gas discharged from the exhaust section 102 and passing through the exhaust line 2.

[0034] The intake and exhaust system 1 further comprises purification means along the exhaust line 2 for purifying the exhaust gases and removing further liquid and / or solid and / or gaseous combustion products contained in the exhaust gases. As shown in the embodiment described herein, such purification means preferably comprises one or more filters 5 a, 5 b arranged downstream of the cooling device 4 . In particular, such filters 5a, 5b consist of an activated carbon filter 5a and a HEPA filter 5b. It should be noted that different numbers of activated carbon filters and / or HEPA filters are also within the scope of protection of the present invention.

[0035] These filters 5a, 5b serve to retain particulates present in the exhaust gas. Although not shown here, the purification means may also preferably comprise one or more carbon dioxide filters. Such carbon dioxide filters may be combined with one or more activated carbon filters 5a and / or one or more HEPA filters 5b. When using e-fuel, such a carbon dioxide filter is not present in the supply and exhaust system 1, since this gas is not produced by the combustion of e-fuel with oxygen. A sensor 3 for measuring the oxygen content, i.e. the oxygen concentration, present in the exhaust gases leaving the exhaust 102 is advantageously arranged along the exhaust line 2, preferably upstream of the cooling device 4.

[0036] The supply and exhaust system 1 may further comprise a recirculation pipeline 10 for fluidly connecting the exhaust line 2 to an intake 101 of the internal combustion engine 100. In practice, such a recirculation pipeline 10 connects the end of the exhaust line 2 arranged downstream of the cooling device 4 to the intake 101. The supply and exhaust system 1 further comprises an oxygen injection means 20 for injecting oxygen into the recirculation pipeline 10 in order to convert the exhaust gas at the outlet of the exhaust line 2 into the aforementioned supply gas, the amount of oxygen injected being determined depending on the oxygen content of the exhaust gas measured by a sensor 3 for measuring the oxygen content.

[0037] In other words, the recirculation pipeline 10 hermetically connects the outlet end of the exhaust line 2 to the intake 101 of the engine 100 itself, creating a truly closed-circuit system that, by its very nature, cannot emit polluting particles, whether solid or gaseous, or even air itself. The injected combustion agent may be in the form of an oxygen mixture, for example nitrous oxide, which makes it possible to enrich the gases leaving the exhaust line 2 and reaching the recirculation pipeline 10 .

[0038] The feed gas taken into the endothermic engine 100 requires the presence of a combustible material for its operation, which is usually oxygen present in the air. However, the already combusted gases exiting the engine 100 contain only trace amounts of oxygen. Therefore, oxygen injection means are provided to inject oxygen, i.e., a combustible material, into the exhaust gases passing through the recirculation pipeline 10. The amount of oxygen injected is the amount necessary for proper combustion to occur within the engine 100, and the amount of oxygen is adjusted accordingly to ensure proper operation of the internal combustion engine 100 (or thermal combustion unit).

[0039] For proper and long-term operation of the supply and exhaust system 1, it is necessary to install along the exhaust line 2 suitable cooling devices 4 that reduce the temperature of the exhaust gases and at the same time remove most of the water vapor that is produced in the exhaust gases as a result of the combustion itself. A cooling device suitable for this purpose is described, for example, in the aforementioned patent application WO 02 / 044999 in the name of the applicant.

[0040] This intake and exhaust system 1 supplies only the combustion agent required by the endothermic engine or other equipment, without supplying other substances (such as nitrogen) that are naturally present in the air, thereby eliminating the production of harmful pollutants such as NOx, which are produced when nitrogen and oxygen combine during combustion with fuel. The absence of NOx that requires thermal or chemical treatment, as achieved by current oxidation catalyst or urea-based SCR systems, also eliminates the pollution associated with the manufacturing, maintenance, and use of current intake and exhaust systems, as discussed above.

[0041] The oxygen injection means 20 further comprises an injection line 21, an injector 22 arranged along the injection line 21 and at least partially within the recirculation pipeline 10, and a dosing valve 23 arranged along the injection line 21 upstream of the injector 22 for adjusting the dosage of oxygen to be injected through the injector 22. The amount of oxygen injected supplements (or supplements) the amount of oxygen combusted in the internal combustion engine 100, thereby achieving a stoichiometric concentration for the hydrocarbon fuel injected into the endothermic engine 100 and keeping the engine 100 running perfectly. Furthermore, the supply and exhaust system 1 includes an oxygen tank 30 for storing oxygen. The oxygen tank 30 is fluidly connected to the injection line 21 upstream of the dosing valve 23. The oxygen tank 30 is provided with a door 31 for filling the oxygen tank 30.

[0042] The system further includes an oxygen generating means 40 (also called an oxygen concentrator), which is fluidly connected to the oxygen tank 30. In an alternative embodiment not shown, the oxygen generating means 40 can be connected directly to the dosing valve 23 . Furthermore, according to the embodiment described herein, the recirculation pipeline 10 is equipped with an expansion vessel 15 that can compensate for volume fluctuations due to an increase or decrease in the mass of gas circulating within the recirculation pipeline 10 itself.

[0043] Furthermore, according to the embodiment shown herein, the supply and exhaust system 1 comprises two heater fans 61 and 62 arranged along the recirculation pipeline 10 . Of the two heater fans 61 and 62 , one heater fan 61 is disposed upstream of the injector 22 , and the other heater fan 62 is disposed downstream of the injector 22 . In this way, it is easy to modify both the increase in flow rate of the supply gas and the increase in pressure of such gas when a given boost or back pressure is desired. Furthermore, since at least one heater fan 61 is located upstream of the expansion vessel 15 and heater fan 62 is located downstream of the expansion vessel 15, the intake and exhaust system 1 can be considered an active dynamic system in which the flow rate of the supplied gas does not depend on the speed given by the engine rotation and / or combustion pressure.

[0044] According to the embodiment described herein, the supply and exhaust system 1 also includes a purified exhaust gas flow meter 55 located along the recirculation pipeline 10 . According to the embodiment described herein, the supply and exhaust system 1 comprises a first sensor 71 arranged along the recirculation pipeline 10 downstream of the injector 22 for measuring the thermodynamic state of the gas, and a second sensor 72 arranged along the recirculation pipeline 10 upstream of the injector 22 for measuring the thermodynamic state of the gas. The first sensor 71 and the second sensor 72 for measuring the thermodynamic state allow the pressure and / or temperature of the circulating gas to be measured, allowing the thermodynamic state of the supplied gas to be constantly monitored and the injection of combustion material into the recirculation pipeline to be appropriately adjusted.

[0045] In particular, the first sensor 71 is capable of monitoring the thermodynamic state of the exhaust gases exiting the exhaust line 2, and the second sensor 72 is capable of monitoring the thermodynamic state of the oxygen-rich exhaust gases in order to convert this oxygen-rich exhaust gas into a feed gas for the engine 100. Furthermore, the exhaust gases exiting the exhaust line 2 can in fact be considered as a fully purified gas, freed from harmful substances and particulates resulting from the combustion of the feed gases that would impair the efficiency of the subsequent combustion.

[0046] As shown in FIG. 1, the air intake and exhaust system 1 includes a control unit 90, which can control the opening and closing of a dosing valve to administer a predetermined amount of oxygen through an injector 22 in response to data from a sensor 3 that detects the oxygen concentration. Alternatively, or in combination with the above roles, such a control unit 90 may control the operation of said one or more heater fans 61,62. In particular, the control unit 90 controls the rotation speed of the heater fans 61 and 62 in response to the air flow rate measured by the exhaust gas flow meter 55 and / or the oxygen concentration detected by the sensor 3 .

[0047] In practice, for example, if a user's acceleration maneuver requires more power, the control unit 90 analyzes the flow rate of the purified exhaust gas and calculates the flow rate required to meet the user's power demand in relation to the measured flow rate, thereby increasing the rotational speed of at least one heater fan (or, according to the embodiments described herein, both heater fans). Furthermore, the control unit 90 can also be used to measure the amount of oxygen detected by the oxygen concentration sensor 3. This improves the accuracy of heater fan speed estimation and allows control so that the stoichiometric conditions between the combustion material and the fuel are always optimal for combustion in the internal combustion engine 100.

[0048] In addition, data detected by the two first and second sensors 71 and 72 for measuring the thermodynamic conditions of the gas, such as temperature and pressure, is stored in the control unit 90 and can be used to control the two heater fans 61 and 62. Furthermore, the purification means of the supply and exhaust system 1 comprises a cyclonic gas / vapor separator (cyclone separator) 95 and a water tank 96 for collecting condensed water vapor contained in the exhaust gas and separated by the cyclonic gas / vapor separator 95. Such a cyclone separator 95 is preferably located downstream of the cooling device 4 .

[0049] In practice, the exhaust gases leaving the exhaust section 102 reach the cooling device 4 where they are heated to a temperature which causes condensation of the water vapor contained in said exhaust gases. This process also involves capturing carbon dioxide contained in the exhaust gas, as the condensed water can dilute and / or capture the carbon dioxide and remove it from the exhaust gas. In the embodiment described herein, the purification means comprises a particle separator 97 upstream of the cooling device 4 and along the exhaust line 2 for separating particles contained in the exhaust gas from the exhaust gas itself. Preferably, such a particle separator may be of the water and / or dry type. In other embodiments, the number of such particle separators 97 may be multiple, and may be pneumatic and dry, without departing from the scope of protection of the present invention. Such particle separators can filter solid particles contained in the exhaust gas. A particle tank 98 is also provided for collecting the particles separated by the particle separator 97 .

[0050] Subsequently, the exhaust gas and the condensed water of the water vapor are separated by a cyclone separator 95. The separated water vapor is transferred to a water tank 96. The remaining part of the exhaust gas passes through the activated carbon filter 5 a and the HEPA filter 5 b before reaching the outlet of the exhaust line 2 . In another embodiment, the exhaust gases also pass through one or more carbon dioxide filters. A sensor 3 for measuring the oxygen content in the exhaust gas is arranged along the exhaust line 2 immediately after the exhaust section 102 and upstream of the cooling and condensing device 4 . At the end of the exhaust line 2 there is a safety valve 99 which intervenes in the event of overpressure, for example if the pressure in the exhaust line 2 exceeds 2.5 bar at that time.

[0051] Furthermore, the air supply and exhaust system 1 includes a water injection device 99 for injecting water from the water tank 96. Such a water injection device 99 is disposed along the exhaust line 2, upstream of the cyclone separator 95 and downstream of the cooling and condensing device 4. In another embodiment, the water injection device 99 can be located upstream of the particle separator 97. In yet another embodiment, the number of water injection devices 99 can be multiple, for example, two, and they can be located upstream of the cyclone separator 95 and the particle separator 97, respectively.

[0052] In yet another embodiment, the water reaching the water injection device 99 can be collected from a water storage / reservoir (not shown) rather than from the water tank 96, or from both. This water storage / reservoir is separate from the water tank 96 and is refilled by the user with water instead of condensed water. In both the above-described embodiment with the water tank 96 and the embodiment with the water reservoir, the head of water reaching the water injection device 99 can be achieved by a suitable pump. The water sprayed by the water injection device(s) 99 can capture most of the carbon dioxide contained in the exhaust gases, as well as any unburned particles present in the gases.

[0053] The purified exhaust gases are pushed by a first heater fan 61 at the outlet of the exhaust line 2 and then pass through a recirculation pipeline 10 where oxygen is injected by an injector 22 . At this point, the oxygen enriched exhaust gas passes through the intake 101 of the engine 100 and becomes the feed gas for the internal combustion engine 100 . Such feed gas is mixed with a hydrocarbon fuel, such as diesel fuel, in the appropriate stoichiometric ratio and injected directly into the cylinders of the internal combustion engine or along the intake line, where it is combusted within the internal combustion engine 100.

[0054] The method for operating the intake and exhaust system 1 for an internal combustion engine 100 or a thermal combustion unit according to any one of claims 1 to 16 of the present invention includes the following steps. a) supplying a feed gas to an internal combustion engine 100 or thermal combustion unit through an intake 101; a') supplying an internal combustion engine 100 or thermal combustion unit with a fuel based on hydrocarbons or derivatives thereof, for example for diesel, b) measuring the oxygen concentration level detected in the exhaust gas at the outlet of the exhaust 102 at the end of the combustion process of the feed gas and the hydrocarbon or derivative-based fuel inside the internal combustion engine; c) cooling and condensing the exhaust gases exiting the exhaust 102 of the internal combustion engine 100;

[0055] Furthermore, the method includes the following steps: d) recirculating the exhaust gases discharged from the exhaust line 2 along the recirculation pipeline 10; and e) injecting oxygen into the recirculation pipeline 10 in order to convert the exhaust gases at the outlet of the exhaust line 2 into feed gas for the internal combustion engine, the amount of oxygen injected being determined depending on the oxygen content of the exhaust gases measured in step b); and f) After step c) and before step d), filtering the exhaust gas to remove further solid and / or gaseous combustion products contained in the exhaust gas and purify the exhaust gas.

[0056] In step e) above, oxygen is introduced into the recirculation pipeline 10 in an amount to maintain the oxygen concentration of the feed gas at the proper stoichiometric level so that continuous combustion is properly carried out within the internal combustion engine 100 or thermal combustion unit. Finally, this method g) measuring the flow rate of the exhaust gas passing through the recirculation pipeline 10; h) increasing or decreasing the rotation speed of one or more heater fans 61, 62 depending on the flow rate of the purified exhaust gas measured in step g) and / or the oxygen content of the exhaust gas measured in step b). [Explanation of symbols]

[0057] 1. Intake and exhaust system (supply and exhaust system) 2 Exhaust line 3. Oxygen concentration sensor 4. Cooling equipment (cooling and condensing equipment) 5a Activated carbon filter 5b HEPA filter 10 Recirculation Pipeline 15 Expansion vessel 20 Oxygen injection means 21 Infusion line 22 Injector 23 Dosing valve 30 Oxygen Tank 40 Oxygen generating means 55 Exhaust gas flow meter 61, 62 Heater fan 71 First Sensor 72 Second Sensor 90 Control Unit 95 Cyclone gas / vapor separator (cyclone separator) 96 Water Tank 97 Particle separator 98 Particle Tank 99 Water injection device 100 Internal combustion engine (endothermic engine) 101 Intake section 102 Exhaust section.

Claims

1. An intake and exhaust system (1) for an internal combustion engine (100) or a thermal combustion unit operating on a fuel based on hydrocarbons or derivatives thereof, comprising at least one intake (101) for introducing a feed gas into said internal combustion engine (100) or said thermal combustion unit; at least one exhaust (102) for discharging exhaust gases from the internal combustion engine (100) or the thermal combustion unit; The intake and exhaust system (1) includes at least one sensor (3) for measuring the oxygen concentration of the exhaust gas discharged from the exhaust section (102), at least one exhaust line (2) fluidly connected to the exhaust section (102), and a cooling device (4) for cooling the exhaust gas discharged from the exhaust section and passing through the exhaust line (2) and condensing water vapor contained in the exhaust gas. The intake and exhaust system (1) further comprises at least one recirculation pipeline (10) fluidly connecting the exhaust line (2) to the intake (101) of the internal combustion engine (100) or the thermal combustion unit; oxygen injection means (20) for injecting oxygen or an oxygen mixture into the recirculation pipeline (10) to convert the exhaust gas at the outlet of the exhaust line into the feed gas; the injection amount of oxygen is set according to the oxygen content of the exhaust gas measured by a sensor for measuring the oxygen concentration; 1. An intake and exhaust system for an internal combustion engine or combustion unit, characterized in that the intake and exhaust system further comprises purification means along the exhaust line (2) for purifying the exhaust gases and removing further liquid and / or solid and / or gaseous combustion products contained in the exhaust gases.

2. 2. An intake and exhaust system for an internal combustion engine or combustion unit according to claim 1, characterized in that the oxygen injection means (20) comprise at least one injection line (21), at least one injector (22) arranged along the injection line and at least partly in the recirculation circuit, and at least one dosing valve (23) arranged along the injection line upstream of the injector (22) for regulating the amount of oxygen or a mixture thereof injected through the injector.

3. 3. An intake and exhaust system for an internal combustion engine or combustion unit according to claim 2, characterized in that it comprises at least one tank (30) containing the oxygen or the oxygen mixture, the tank (30) being fluidly connected to the injection line (21) upstream of the dosing valve (23).

4. An oxygen generating means (40) is provided, 4. The intake and exhaust system of an internal combustion engine or combustion unit according to claim 3, wherein the oxygen generating means (40) is fluidly connected to the tank (30) or the injection line upstream of the dosing valve (23).

5. 2. An intake and exhaust system for an internal combustion engine or combustion unit according to claim 1, characterized in that the pre-pre-recirculation pipeline (10) comprises at least one expansion vessel (15).

6. 3. An intake and exhaust system for an internal combustion engine or combustion unit according to claim 2, characterized in that it comprises at least two heater fans (61, 62) arranged along the recirculation pipeline (10), one of the heater fans being arranged upstream of the injector and the other of the heater fans being arranged downstream of the injector.

7. 7. An intake and exhaust system for an internal combustion engine or combustion unit according to claim 6, characterized in that it comprises at least one flow meter (55) for the purified exhaust gases arranged along the recirculation pipeline (10).

8. 3. An intake and exhaust system for an internal combustion engine or combustion unit according to claim 2, characterized in that it comprises at least one first sensor (71) for measuring the thermodynamic state, arranged along the recirculation pipeline downstream of the injector, and at least one second sensor (72) for measuring the thermodynamic state, arranged along the recirculation pipeline (10) upstream of the injector (22).

9. 8. An intake and exhaust system for an internal combustion engine or combustion unit according to claim 7, characterized in that it comprises at least one control unit (90) capable of controlling the opening and closing of the dosing valve (23) and / or controlling the operation of the heater fans (61, 62).

10. 10. The intake and exhaust system of an internal combustion engine or combustion unit according to claim 9, wherein the control unit controls the rotation speed of the heater fans (61, 62) depending on the flow rate of the purified exhaust gas measured by the flow meter (55) and / or depending on the oxygen concentration measured by a sensor (3) for detecting the oxygen concentration.

11. 10. An intake and exhaust system for an internal combustion engine or combustion unit according to claim 9, characterized in that the control unit is capable of controlling the opening and closing of the dosing valve (23) depending on data from a sensor (3) for detecting the oxygen concentration in order to dose a predetermined amount of the oxygen through the injector.

12. 2. An intake and exhaust system for an internal combustion engine or combustion unit according to claim 1, characterized in that the purification means comprise at least one cyclonic gas / vapor separator (95) and at least one water tank (96) for collecting condensed water vapor contained in the exhaust gases and separated from the cyclonic gas / vapor separator (95).

13. 2. An intake and exhaust system for an internal combustion engine or combustion unit according to claim 1, characterized in that the purification means further comprise one or more filters (5a, 5b) arranged along the exhaust line (2).

14. 14. An intake and exhaust system for an internal combustion engine or combustion unit according to claim 13, wherein the filter is selected from an activated carbon filter, a HEPA filter and a carbon dioxide filter.

15. 13. An intake and exhaust system for an internal combustion engine or combustion unit according to claim 12, characterized in that the purification means comprise at least one water and / or dry particle separator (97) along the exhaust line (2) upstream of the cooling device (4).

16. 16. An intake and exhaust system for an internal combustion engine or combustion unit according to claim 15, characterized in that the purification means comprises at least one water injection device (99) for injecting water contained in the water tank (96) or storage / reserve container, the water injection device (98) being arranged along the exhaust line (2) upstream of the cyclonic gas / vapour separator (95) and / or the particle separator (97).

17. 2. A method for operating an intake and exhaust system of an internal combustion engine or combustion unit according to claim 1, comprising: a) supplying the supply gas to the internal combustion engine or the thermal combustion unit through the intake; a') supplying said internal combustion engine or said thermal combustion unit with said fuel based on hydrocarbons or derivatives thereof; b) measuring the oxygen concentration level detected in the exhaust gas at the outlet of the exhaust at the end of the combustion step of the feed gas and the fuel based on hydrocarbons or derivatives thereof inside the internal combustion engine or the thermal combustion unit; and c) cooling and condensing the exhaust gases exiting the exhaust of the internal combustion engine or the thermal combustion unit; and d) recirculating the exhaust gases discharged from the exhaust line along the recirculation pipeline (10); e) injecting oxygen into the recirculation pipeline (10) to convert the exhaust gases at the outlet of the exhaust line into the supply gas for the internal combustion engine or the thermal combustion unit, the amount of oxygen injected being determined depending on the oxygen content of the exhaust gases measured in step b); f) filtering the exhaust gas after step c) and before step d) to remove any further liquid and / or solid and / or gaseous combustion products contained in the exhaust gas.

18. 18. The method of claim 17, wherein step e) of the internal combustion engine or combustion unit is controlled to introduce oxygen in an amount to maintain the oxygen concentration of the supply gas at a proper stoichiometric level, thereby ensuring proper continuous combustion within the internal combustion engine or thermal combustion unit.

19. the intake and exhaust system of the internal combustion engine or combustion unit comprises one or more heater fans (61, 62) arranged along the recirculation pipeline (10); The method of operating the intake and exhaust system of the internal combustion engine or combustion unit may further comprise: g) measuring the flow rate of the exhaust gas passing through the recirculation pipeline; h) increasing or decreasing the rotational speed of the heater fan depending on the flow rate of the purified exhaust gas measured in step g) and / or the oxygen content of the exhaust gas measured in step b).

Images