LOW PARTICLE EMISSION ENGINE

Description

[0001] The present invention relates to a low-particulate emission engine, and particularly a very large turbodiesel engine intended for ship propulsion. It also relates to a method for reducing particulate emissions from such an engine.

[0002] Very large turbodiesel engines designed for ship propulsion are either two-stroke (slow-running) or four-stroke (semi-high-running). These engines can generate power ranging from 1 MW to almost 100 MW for the largest models. They consume liquid fuels, collectively known as "fuel oils," including heavy fuel oils (HFO), intermediate fuel oils (MDO, for "Marine Diesel Oil"), and light fuel oils, which have low viscosity and sulfur content, similar to those used on land for domestic applications. These engines have the drawback of emitting components from incomplete combustion, in the form of particles also called "solid unburned fuel," which contain unoxidized carbon and are commonly referred to as soot, and "gaseous unburned fuel."The first type consists of organic particles, particularly ultrafine particles of soot carbon, more commonly known as "black carbon," ranging in size from a few nanometers to about ten micrometers. The average size of particles emitted by such a diesel engine is around 100 nm. The gaseous components from "unburned gases" are also of various kinds, including carbon monoxide, unburned hydrocarbons, polycyclic aromatic hydrocarbons, volatile organic compounds, and non-methane non-volatile organic compounds. These various emissions, resulting from the incomplete combustion of engines, in the form of solid particles or gaseous components, generate numerous and serious effects on human health.

[0003] Solutions exist in the automotive sector for treating particulate matter emissions from small engines. These solutions involve a post-combustion approach, relying in particular on the use of filters. However, these filtration solutions are difficult to implement on all existing engines, especially the aforementioned marine engines, due to factors of scale and cost. Furthermore, these solutions have the drawback of reducing the engine's thermodynamic efficiency, leading to increased fuel consumption.

[0004] Documents WO2010098746, WO0151800, EP2511510 and US2005053875 disclose various examples of engine embodiments including catalytic devices or catalytic devices for engines, applied to different technical fields.

[0005] In parallel, a prior art solution is described in document FR2837214 in another field, which recommends, firstly, mixing catalytic vapors of the methyl cyclopentadienyl manganese tricarbonyl type with the combustion air of a boiler, and secondly, injecting fine droplets of this catalytic agent directly into the fuel, in order to reduce sulfur and nitrogen oxides at the boiler outlet. This solution allows for a significant reduction in pollution generated by boiler combustion. This document thus concerns the specific field of boilers and demonstrates that a catalyst can reduce pollution from emissions, these emissions being sulfur compounds.

[0006] A general object of the invention is to propose a solution for improving engines, more particularly very large ship diesel engines, by reducing the harmful particles emitted by these engines.

[0007] To this end, the invention is based on a ship engine, comprising an intake manifold, characterized in that it includes a catalytic device implementing the mixing of a catalyst precursor which includes an organometallic compound, in particular a methyl cyclopentadienyl manganese tricarbonyl component, with an oxidizer, and in that the catalytic device is arranged upstream of a compression device, such that this compression device increases the pressure of the mixture comprising the oxidizer and the catalyst precursor to a value greater than or equal to 2 bars, or even greater than or equal to 4 bars, this pressure value being measured at the level of its inlet into the intake manifold.

[0008] The ship engine is a turbo engine comprising a turbo blower, the compression device being this turbo blower, and the catalytic device being positioned upstream of the turbo blower so that said mixture comprising the oxidizer and the catalyst precursor is conducted from the outlet of the catalytic device to the turbo blower, where it undergoes a pressure increase, and then from the turbo blower to the intake manifold.

[0009] The ship engine includes a refrigerant heat exchanger disposed between the turbofan and the intake manifold to cool the mixture comprising the oxidizer and the catalyst precursor to a temperature value less than or equal to 50°C, or even less than or equal to 40°C.

[0010] The compression device may include at least two turbochargers arranged in series. The ship engine may include at least one heat exchanger arranged between two turbochargers to cool the mixture comprising the oxidizer and the catalyst precursor.

[0011] This engine can be a turbo engine including a turbo blower, the mixture including the oxidizer and the catalyst precursor exiting the catalytic device can be connected to an intake line to the intake manifold by an injection zone arranged downstream of the turbo blower and a cooling exchanger.

[0012] The injection zone may include a diffusion rack comprising a hollow metal body with multiple cross-shaped perforations and positioned in a plane perpendicular to the direction of the oxidizing flow, to allow mixing of the catalyst precursor vapors with the oxidizing flow.

[0013] The catalytic device may include a medium comprising cellulose fibers and / or woven fibers, such as certain cottons, onto which the catalyst precursor is injected in liquid form and is evaporated and mixed with an oxidant upon contact with said medium.

[0014] The catalytic device may include a liquid catalyst precursor reservoir, and may be configured for at least partial evaporation of said catalyst precursor within the oxidant.

[0015] The liquid catalyst precursor may comprise an organometallic or methyl cyclopentadienyl manganese tricarbonyl concentration greater than or equal to 90% of the total weight of the catalyst precursor.

[0016] The engine for a ship can be a power engine with a power output between 1 MW and 100 MW.

[0017] The invention also relates to a method for reducing particulate emissions from a ship's engine, characterized in that it comprises the implementation of the following steps: Mixing a catalyst precursor comprising an organometallic compound, in particular a methyl cyclopentadienyl manganese tricarbonyl component, with an oxidizer, then increasing the pressure of said mixture by a compression device, to a pressure value greater than or equal to 2 bar, or even greater than or equal to 4 bar, then injecting said mixture under pressure into an intake manifold for a combustion chamber of an engine.

[0018] These objects, features and advantages of the present invention will be described in detail in the following description of a particular embodiment, given by way of non-limiting example, in relation to the accompanying figures, among which: [ Fig. 1 ] There figure 1 schematically represents an engine according to one embodiment of the invention. Fig. 2 ] There figure 2 illustrates pressure evolution curves as a function of the crankshaft angle of the engine according to the embodiment of the invention, compared with a prior art engine. Fig. 3 ] There figure 3 schematically represents a variant of the engine according to an embodiment of the invention.

[0019] Advantageously, it has been discovered that the use of a precursor to a liquid organometallic catalyst, specifically a precursor containing methyl cyclopentadienyl manganese tricarbonyl, provides a surprising reduction in particulate matter emitted by very large ship engines, provided it is used under specific conditions, while also improving the efficiency of such engines. These surprising results were not anticipated after the implementation of such a catalyst in a boiler to reduce sulfur emissions.

[0020] This use will be detailed in the context of a specific embodiment below.

[0021] There figure 1 This schematically represents a very large turbo diesel engine 1 for a ship according to an embodiment of the invention. This engine 1 comprises, in a known manner, an intake manifold 2, a combustion chamber 3 (cylinders), and an exhaust manifold 4. It further comprises a turbocharger 9, for the turbo function, driven by the exhaust gases guided by an exhaust pipe 5 from the exhaust manifold 4 to the turbocharger 9. This turbocharger increases the pressure of the oxidizer, i.e., air in this embodiment, before it enters the intake manifold 2 via an intake pipe 6.

[0022] According to the embodiment, the engine includes a catalytic device 10 located upstream of the turbofan 9. The catalytic device 10 mixes a precursor of the aforementioned catalyst with the combustion air. This catalytic device 10 is positioned upstream of the turbofan 9 so that the mixture comprising air (or any other gas intended as an oxidizer) and the catalyst precursor is then guided through the turbofan 9.

[0023] The catalytic device 10 can be of the type described in document FR3059565, allowing the evaporation of the liquid catalyst precursor and its subsequent mixing and transport within the combustion air. At the outlet of the catalytic device 10, the air laden with catalyst precursor is directed via a duct 7 to the turbofan 9.

[0024] In this embodiment, the catalytic device 10 includes a hydraulic subassembly, not shown, comprising a reservoir for storing the catalyst precursor. This reservoir is mounted above a containment tray. Both elements are suitable for storing a catalyst precursor in liquid form, in particular an organometallic catalyst as previously mentioned. A liquid level detection device, in particular a level detector, is positioned on top of the reservoir to determine the quantity of catalyst precursor available in the reservoir. In the embodiment shown, the level detector triggers an alert when the level of catalyst precursor falls below a predefined threshold. This hydraulic subassembly is connected to an air-handling subassembly, in which the liquid catalyst precursor can be evaporated and mixed with air.For example, a catalyst precursor containing methyl cyclopentadienyl manganese tricarbonyl becomes an active material at a temperature of approximately 230 to 240°C under the pressure conditions of engine 1. This process is advantageously carried out using a medium comprising cellulose fibers and / or woven fibers, such as certain cottons. Alternatively, this evaporation and mixing can be achieved by any other means.

[0025] According to the invention, the air mixture containing the catalyst precursor is then pressurized within the turboblower 9 to a relative pressure of 5 bar, or, according to the invention, greater than or equal to 2 bar, or even greater than or equal to 4 bar. This pressure is advantageously between 2 and 6 bar, or even between 4 and 6 bar. The catalytic device 10 is positioned upstream of the turboblower 9, and the latter forms a compression device for the mixture comprising the oxidizer and the catalyst precursor. It should be noted that, throughout this description, the units given in bar refer to absolute bar.

[0026] It is also understood that, throughout this description, "compression device" means a device having in particular a compression ratio greater than 1.5, or even greater than 4. According to the invention, it makes it possible to raise the pressure of the mixture from a value close to atmospheric pressure to a pressure greater than or equal to 2 bars, or even greater than or equal to 4 bars, according to the values ​​mentioned above.

[0027] The turbofan also has the effect of increasing the temperature of the air containing the catalyst to a value that can, for example, be between 150°C and 200°C. For this reason, a cooling exchanger 8 is arranged at the outlet of the turbofan 9, at the level of the intake duct 6, to reduce this temperature, according to the invention, below a value of 50°C, or even below a value of 40°C, for example to around 30°C.

[0028] The resulting pressure and / or temperature conditions allow for optimized, even ideal, distribution of the catalyst vapors within the oxidant, ensuring their homogeneous distribution. The catalyst vapors are thus distributed at a molecular scale. They are atomized to the molecular level within the oxidant, which acts as their transport medium. Prepared in this way, the organometallic precursor offers the best possible specific surface area and optimal distribution within the oxidant's gaseous environment. This solution allows it to act according to a "spin" effect, making it highly reactive and fully available to become its catalytic form.

[0029] This conditioning of the catalyst precursor helps release the combustion catalyst into the combustion chamber, where it becomes the ideal and complementary agent for interacting with the carbon present in the combustion chamber in all its solid and gaseous forms, thereby achieving its near-complete thermal oxidation. This effect leads to the destruction of unburned particulate and gaseous particles through their gasification, transforming the available carbon into carbon dioxide. Furthermore, the catalyst, thus conditioned, remains active throughout its entire path from the combustion chamber to the exhaust outlet. The desired result can therefore be achieved with this conditioned catalyst.

[0030] The engine is further advantageously automatically controlled by a control unit, including a computer, based on information transmitted by certain sensors of engine 1. These sensors allow, for example, the engine load level, including its speed, engine torque, cylinder head pressure, etc. This engine control advantageously incorporates automatic regulation of the amount of catalyst used. According to the invention, this amount is between 5 and 50 decagrams of catalyst per ton of fuel.

[0031] Specifically, for the methyl cyclopentadienyl manganese tricarbonyl component, the catalyst precursor accounts for four times the weight of the catalyst; that is, it comprises, for example, a volatile fraction of approximately 75% by mass. According to the invention, in order to obtain a quantity of catalyst between 5 and 50 decagrams per ton of fuel, it will be necessary to inject between 20 and 200 decagrams of catalyst precursor per ton of fuel.

[0032] We measure at the output of motor 1, according to the embodiment, which the solution allows to be eliminated from: 50 to 99% of carbonaceous particles; 70 to 99% of ultrafine particles with a size between approximately 30 and 150 nm; 50% to 99% of unburned hydrocarbons from the combustion of heavy fuel oils, when their initial concentration is between 200 and 500 ppm, and 30% to 90% of hydrocarbons from the combustion of MDOs when their initial concentration is between 1,000 and 4,500 ppm.

[0033] Furthermore, at the same engine load level 1, the complete thermal oxidation of carbon thanks to the advantageous catalysis of the invention, and the accelerated kinetics of the combustion chemistry under the catalytic effect, generate an increase in gas pressure, which varies with the number of crankshaft degrees during the downward stroke of the engine piston. figure 2 illustrates this phenomenon: curve 20 represents the gas pressure in a prior art engine, and curve 21 represents the gas pressure in an identical engine but equipped with the catalytic device according to the embodiment of the invention.

[0034] Changing the engine settings according to the embodiment of the invention makes it possible to take advantage of this effect illustrated by the figure 2 and to reduce engine consumption while maintaining the power and torque delivered to the shaft. This translates into an increase in the average thermodynamic efficiency of the engine, with specific consumption decreasing by 3 to 12 g / kWh, depending on the type of engine (two-stroke or four-stroke) and its load level (between 25% and 100%).

[0035] Another indirect advantage of eliminating soot from the engine exhaust, according to this embodiment, is keeping the turbines of the turbofan 9 clean. Indeed, the metal surfaces of these turbines are no longer greasy or fouled. This reduces, or even eliminates, preventive and corrective maintenance operations and ensures optimal lifespan for the turbine blades. Furthermore, the efficiency of the turbofan 9 remains consistently at its maximum, which contributes to the overall efficiency of the engine 1.

[0036] Finally, the engine 1 according to the embodiment of the invention not only makes it possible to virtually eliminate emissions of polluting particles, but also to improve the efficiency of the engine.

[0037] There figure 3 represents a variant embodiment of the invention, in which the catalytic device 10 is arranged downstream of the turbofan 9 of the engine 1. For simplicity, the same reference numerals are used to designate identical or similar components with the embodiment described by reference to the figure 1 .

[0038] In this embodiment, the catalytic device 10 is positioned downstream of the turbofan 9 and its coolant exchanger. This means that the mixture comprising the oxidizer and the catalyst precursor generated by the catalytic device is injected downstream of the turbofan, at an injection point 16 in the intake duct 6. A diffuser can be positioned in a plane perpendicular to the direction of the oxidizer flow at this injection point 16 to allow mixing of the catalyst precursor vapors with the oxidizer flow. Such a diffuser can be made of a hollow metal body with several hundred cross-shaped perforations, for example, each with a maximum diameter of 5 mm², and with beveled edges distributed uniformly on all faces except the leading edge of the flow.In this embodiment, two turbochargers 19 are mounted in series, between the catalytic device 10 and the injection zone 16. A heat exchanger 18 is further arranged between the two turbochargers 19.

[0039] The turbochargers 19 are driven by a portion of the exhaust gases. They are designed to operate within their optimal efficiency range, while being regulated exclusively by a fraction of the exhaust gases from engine 1. They can move up to approximately 500 Nm³ of carrier air from the catalyst. Alternatively, the compression system could include more than two turbochargers. It could also include several heat exchangers to cool the air / catalyst mixture.

[0040] The result obtained is essentially identical to that of the method of implementation of the figure 1 Indeed, this configuration allows the pressure to be increased in the same ranges of values ​​as before, while maintaining the temperature below the same threshold value, via the exchanger 18. In this variant, the two turbochargers 19 together form a compression device for the oxidizer / catalyst precursor mixture.

[0041] According to an alternative embodiment, compatible with both embodiments of figures 1 And 3 The catalytic device 10 further includes hardware and / or software components enabling the implementation of a mixing process for a catalyst precursor to improve engine 1, either automatically or semi-automatically. The mixing process is carried out via electromechanical sensors and actuators, electrically powered and regulated by one or more programmable logic controllers (PLCs) that can be remotely controlled.

[0042] Note that in all the designs considered above, the air used can be replaced by any other gaseous oxidizer or any other transport gas. Furthermore, note that the oxidizer containing a catalyst precursor represents, by mass, only a fraction of the air entering the engine's combustion chamber.

[0043] In all embodiments, the catalytic device could ultimately be of any form, provided that it mixes a catalyst precursor within an oxidant in a form that allows its transport by the oxidant. Furthermore, the compression device for this mixture could also have a form other than those described in the embodiments.

[0044] The invention also relates to a method for reducing particulate emissions from an engine, in particular a very large ship engine, which includes the implementation of the following steps: Mixing a catalyst precursor with an oxidizer, then increasing the pressure of said mixture to a pressure value greater than or equal to 2 bars, or even greater than or equal to 4 bars, then injecting said mixture under pressure into an intake manifold for the combustion chamber of an engine.

[0045] As explained previously, the process uses a precursor to a liquid organometallic catalyst. A highly advantageous application is to use a catalyst precursor that includes, or is composed solely of, methyl cyclopentadienyl manganese tricarbonyl. Advantageously, the concentration of the organometallic compound in the catalyst precursor is greater than or equal to 99% of the total weight of the catalyst precursor. This solution effectively achieves the desired objectives and makes it possible to reduce, or even eliminate, all particulate emissions from an engine, particularly a very large turbodiesel engine for marine applications.

[0046] The described solution offers the advantage of efficient evaporation of the catalyst precursor produced by the oxidizer, which thus becomes the transport medium for the catalyst vapors. Alternatively, the oxidizer acts as the transport medium for a catalyst precursor in liquid form, particularly as droplets. The catalyst precursor may be present, in whole or in part, as droplets before being completely evaporated and ideally distributed throughout the oxidizer at the compression device.

[0047] According to a third embodiment, illustrated in dotted lines in the figures 1 And 3and implemented alternatively (not supported by the invention) or in combination with the first or second embodiment previously described, the ship engine 1 is characterized in that it comprises the exhaust manifold 4 and at least one catalytic device 10' comprising a compression injection means, in particular by compressed air or by water, at least configured to ensure the projection in droplet form of a liquid catalyst precursor composed of an organometallic, in particular a methyl cyclopentadienyl manganese tricarbonyl component, and its mixing with exhaust gases included in the exhaust manifold 4.

[0048] Such a projection under compression, also called "nebulization" or "atomization," corresponds to the cold transformation of the liquid catalyst precursor into a cloud, or mist, of droplets. Specifically, according to an optional feature, the catalytic device 10' can be configured to produce droplets with a size ranging from 10 to 500 µm, particularly 20 to 100 µm.

[0049] As stated in reference to the figure 1 The engine 1 comprises the intake manifold 2 and the combustion chamber 3 comprising a plurality of cylinders. It further comprises a turbocharger 9 which functions as a compression device and is driven by the exhaust gases guided by the exhaust pipe 5 from the exhaust manifold 4 to the turbocharger 9. Alternatively, and as explained with reference to the figure 3 , engine 1 may include the two turbochargers 19 mounted in series and the heat exchanger 18.

[0050] According to the present embodiment, the catalytic device 10' is at least configured to ensure the injection of the catalyst precursor downstream of the combustion chamber 3.

[0051] According to a preferred feature, the catalytic device 10' is configured to inject the catalyst precursor directly at the exhaust manifold 4 at at least one injection site 21. In particular, the catalytic device 10' can be configured to inject the catalyst precursor immediately at the exhaust outlet of at least one of the engine cylinders 1.

[0052] According to a particular embodiment, not shown, the catalytic device 10' can be configured to inject the catalyst precursor directly at the exhaust manifold 4 into a plurality of injection sites 21. In particular, the engine 1 can include as many injection sites 21 as there are cylinders.

[0053] In particular, the catalytic device 10' may include at least one supply line 22 configured to ensure the circulation of the catalytic precursor to the injection site(s) 21.

[0054] The objective of this embodiment is to perform exhaust gas aftertreatment at a temperature favorable to the catalytic oxidation capacity of the carbon in the catalyst precursor, which instantly becomes a catalyst. Specifically, the catalytic device 10' can be configured to inject the catalyst precursor into a zone of the exhaust manifold 4 with a temperature of approximately 450 to 600°C, particularly in the range of 550 to 600°C, for example, around 580°C.

[0055] According to a feature of the third embodiment, the injection means for the catalytic device 10' may advantageously include at least one injection nozzle, in particular a nebulizing nozzle, for the catalyst precursor in liquid form. Such an injection nozzle is disposed at at least one injection site 21 in the exhaust manifold 4. As previously described, the injection means may include a plurality of injection nozzles, for example, each disposed at an injection site 21.

[0056] According to one particular embodiment, such an injection nozzle is a bi-fluid nozzle configured to simultaneously inject the catalyst precursor and a fluid, in particular compressed air or water, into the exhaust manifold 4.

[0057] Optionally, but advantageously, the catalytic device 10' may include a cooling device, not shown, for the injection means, in particular for at least the injection nozzle. Such a cooling device may, by way of non-limiting example, provide cooling for the injection means by means of a fluid identical to the fluid injected into the exhaust manifold 4, namely compressed air or water.

[0058] Such a fluid then serves, on the one hand, as an injection carrier and contributes to the atomization of the liquid catalyst precursor, and, on the other hand, as a cooling agent for the injection system. This arrangement advantageously prevents the catalyst precursor from reacting or degrading within the injection system, for example, the injection nozzle, and thus prevents its malfunction.

[0059] The catalyst precursor is thus projected in liquid form as droplets by means of injection, which, once in the exhaust manifold 4, are instantly vaporized, or " flashées " according to the term derived from English, due to the temperature conditions of the exhaust manifold 4 allowing the catalyst precursor to react to form the catalyst.

[0060] The circulation of exhaust gases in the exhaust manifold 4 then advantageously allows the mixing of the exhaust gases and the catalytic converter, as well as the homogenization of this mixture. The same applies to the circulation of this mixture in the turbocharger 9, in order to actuate it.

[0061] According to a variant of this third embodiment, the engine 1 may include within the catalytic device 10, 10': a first subunit of the catalytic device 10' comprising the compression injection means and configured to ensure the projection in droplet form of a catalyst precursor composed of an organometallic, in particular a methyl cyclopentadienyl manganese tricarbonyl component, and its mixing with exhaust gases included in the exhaust manifold 4; a second subunit of the catalytic device 10, implementing the mixing of the catalyst precursor with the oxidant in gaseous form and arranged upstream of the compression device so that this compression device increases the pressure of the mixture comprising the oxidant and the catalyst precursor to a value greater than or equal to 2 bar, or even greater than or equal to 4 bar, this pressure value being measured at the level of its inlet in the intake manifold 2.

[0062] Note that, if such a particular example of the catalytic device is represented, for the sake of clarity, as two subunits 10, 10' with distinct positions on the figures 1 And 3 These are included in the same catalytic device.

[0063] According to such a variant, the second subunit of the catalytic device 10 has the characteristics of the catalytic device 10 as described above with reference to the first or second embodiment; the description of said embodiments therefore applies mutatis mutandis to the present variant. In particular, such a second subunit 10 of the catalytic device may include, as previously described, the hydraulic subassembly, not shown, comprising a reservoir for storing the catalyst precursor, and the aerodynamic subassembly, in which the liquid catalyst precursor can be evaporated and mixed with air.

[0064] In particular, the hydraulic subassembly may be common to the first subunit 10' and the second subunit 10 of the catalytic device.

[0065] In particular, the first subunit of the catalytic device 10' may then include the supply line 22, which connects the hydraulic subassembly to at least one of the injection sites 21 and is configured to allow the circulation of the catalyst precursor from the hydraulic subassembly to the injection site(s) 21.

[0066] The engine 1 can, in addition, as previously explained, be automatically controlled by the control unit based on information transmitted by the sensors of the engine 1. In particular, such information may relate to the engine load level, its speed, engine torque, cylinder head pressure, exhaust manifold temperature, etc.

[0067] In particular, depending on the embodiment or variant implemented, the engine 1 can be automatically controlled by the control unit so that the catalytic device implements, as required, all or part of the following options: the injection by projection in the form of droplets of the liquid catalyst precursor composed of an organometallic, in particular a methyl cyclopentadienyl manganese tricarbonyl component, and its mixing with exhaust gases included in the exhaust manifold 4, in particular as set out with reference to the third embodiment; the mixing of the catalyst precursor with the oxidizer upstream of the compression device so that this compression device increases the pressure of the mixture comprising the oxidizer and the catalyst precursor to a value greater than or equal to 2 bar, or even greater than or equal to 4 bar, this pressure value being measured at the level of its inlet into the intake manifold 2, as set out with reference to the first or second embodiment.

[0068] Advantageously, the catalytic device 10' can be configured to inject between 0.5 and 15 milligrams of catalyst per m³ of exhaust gas. For example, for a catalyst precursor containing a methyl cyclopentadienyl manganese tricarbonyl component, the catalytic device 10' can be configured to inject between 2 and 60 milligrams of catalyst precursor per m³ of exhaust gas. In particular, the engine control unit can incorporate automatic regulation of the amount of catalyst used and / or the size of the projected droplets.

[0069] The injection of the post-combustion catalyst precursor thus helps to interact with the carbon present in the exhaust manifold, achieving its almost complete thermal oxidation. This effect leads to the destruction of unburned particulate and gaseous particles through their gasification, transforming the available carbon into carbon dioxide.

Claims

1. An engine (1) for a ship propelled by a very large turbo diesel engine, notably an engine with power between 1 MW and 100 MW, comprising an intake manifold (2) a catalytic device (10) implementing the mixing of a catalyst precursor which comprises an organometallic compound, notably a methylcyclopentadienyl manganese tricarbonyl component, with a fuel oxidizer, and in that the catalytic device (10) being arranged upstream of a compression device, which is disposed upstream of the intake manifold (2), so that this compression device increases the pressure of the mixture comprising the fuel oxidizer and the catalyst precursor to a value greater than or equal to 2 bar, or even greater than or equal to 4 bar, this pressure value being measured at its entry into the intake manifold (2), characterized in that the engine : - is a turbocharged engine comprising a turboblower (9), the compression device being the turboblower (9), and the catalytic device (10) is positioned upstream of the turboblower (9) so that said mixture comprising the fuel oxidizer and the catalyst precursor is conducted from the outlet of the catalytic device (10) to the turboblower (9), where it undergoes an increase in pressure, then from the turboblower (9) to the intake manifold (2); - comprises an intercooler heat exchanger (8) disposed between the turboblower (9) and the intake manifold (2) to cool the mixture comprising the fuel oxidizer and the catalyst precursor to a temperature value less than or equal to 50°C, or even less than or equal to 40°C; - is configured to use a quantity of catalyst between 5 and 50 decagrams per ton of fuel, corresponding to a quantity of 20 to 200 decagrams of catalyst precursor per ton of fuel.

2. The engine (1) for a ship according to the preceding claim, characterized in that the catalytic device (10) comprises a medium comprising cellulose fibers and / or woven fibers, such as some cottons, onto which the catalyst precursor is injected in liquid form and is evaporated and mixed with a fuel oxidizer in contact with said medium.

3. The engine (1) for a ship according to one of the preceding claims, characterized in that the catalytic device (10) comprises a tank of liquid catalyst precursor and is configured for the at least partial evaporation of said catalyst precursor in the fuel oxidizer.

4. The engine (1) for a ship according to the preceding claim, characterized in that the liquid catalyst precursor comprises an organometallic compound or methylcyclopentadienyl manganese tricarbonyl concentration greater than or equal to 90% of the total weight of the catalyst precursor.

5. The engine (1) for a ship according to one of the preceding claims, characterized in that it is an engine with power between 1 MW and 100 MW.

6. The engine (1) for a ship according to one of the preceding claims, further comprising an exhaust manifold (4) and at least one catalytic device (10') configured to ensure injection of a liquid catalyst precursor composed of an organometallic, notably a methyl cyclopentadienyl manganese tricarbonyl component, downstream of the combustion chamber (3), said catalytic device (10') comprising an injection means by compression, notably by compressed air or by water, at least configured to ensure projection in the form of droplets of the liquid catalyst precursor and its mixing with exhaust gases comprised in the exhaust manifold (4).

7. The engine (1) for a ship according to the preceding claim, wherein the catalytic device (10') configured to ensure the injection of a liquid catalyst precursor downstream of the combustion chamber (3) is configured to produce droplets having a dimension of the order of 10 to 500 µm, notably 20 to 100 µm.

8. The engine (1) for a ship according to claim 6 or 7, wherein the catalytic device (10') configured to ensure injection of a liquid catalyst precursor downstream of the combustion chamber (3) is configured so as to inject the catalyst precursor at a zone of the exhaust manifold (4) having a temperature of the order of 450 to 600°C, notably of the order of 550 to 600°C, for example about 580°C.

9. The engine (1) for a ship according to one of claims 6 to 8, wherein the catalytic device (10') configured to ensure injection of a liquid catalyst precursor downstream of the combustion chamber (3) comprises a cooling device for the injection means capable of ensuring cooling of the injection means by means of a fluid identical to the fluid injected into the exhaust manifold (4), namely notably compressed air or water.

10. The engine (1) for a ship according to one of claims 1 to 5, further comprising an exhaust manifold (4), the catalytic device (10, 10') comprising: • a first sub-unit of the catalytic device (10') comprising an injection means by compression configured to ensure projection in the form of droplets of a catalyst precursor composed of an organometallic, notably a methyl cyclopentadienyl manganese tricarbonyl component, downstream of the combustion chamber (3) and its mixing with exhaust gases comprised in the exhaust manifold (4); and • a second sub-unit of the catalytic device (10), implementing the mixing of the catalyst precursor with the oxidizer in gaseous form and arranged upstream of the compression device so that this compression device increases the pressure of the mixture comprising the oxidizer and the catalyst precursor to a value greater than or equal to 2 bars, or even greater than or equal to 4 bars, this pressure value being measured at its entry into the intake manifold (2).

11. A method of reducing emissions of particles from a ship engine (1), propelled by a very large turbo diesel engine, notably an engine with power between 1 MW and 100 MW, characterized in that it comprises implementing the following steps: - mixing of a catalyst precursor which comprises an organometallic compound, notably a methyl cyclopentadienyl manganese tricarbonyl component, with an oxidizer by a catalytic device (10) so as to use a quantity of catalyst between 5 and 50 decagrams per ton of fuel, corresponding to a quantity of 20 to 200 decagrams of catalyst precursor per ton of fuel, then - increasing the pressure of said mixture by a compression device, to a pressure value greater than or equal to 2 bars, or even greater than or equal to 4 bars and cooling the mixture comprising the oxidizer and the catalyst precursor to a temperature value less than or equal to 50°C, or even less than or equal to 40°C, then - injection of said mixture under pressure into an intake manifold (2) for a combustion chamber of an engine (1).