EP1073833A1

EP1073833A1 - Method and device for improving combustion in an internal combustion engine

Info

Publication number: EP1073833A1
Application number: EP00907703A
Authority: EP
Inventors: Jean-Louis Boisset; Patrick Jean Georges Siegler-Lathrop
Original assignee: Boisset Jean-Louis; Siegler-Lathrop Patrick Jean Georges
Current assignee: Boisset Jean-Louis; SIEGLER-LATHROP, PATRICK JEAN GEORGES
Priority date: 1999-02-23
Filing date: 2000-02-23
Publication date: 2001-02-07
Also published as: CA2329404A1; AU2920200A; PL343763A1; BR0004979A; FR2790038A1; WO2000050760A1; JP2002538356A; CN1297512A

Abstract

The invention concerns a method for improving fuel combustion in appliances wherein a fuel/oxidant mixture is burnt to supply energy whereby a solid organism is sublimed in an oxidant gas stream previous to being mixed with a fuel, the resulting mixture being then burnt to supply energy. The invention is characterised in that the sublimed volume proportion of said organic compound relative to the oxidant gas volume forming part of the mixture, ranges between 0.5 and 15 ppm. The invention is useful for improving combustion in an internal combustion engine, in particular of a motor vehicle, or in an industrial burner.

Description

The present invention relates to a method and a device for improving the combustion of fuels in devices in which a mixture of a fuel and an oxidant is burned to provide energy.

Document WO 98/01662 in the name of the Applicants describes a method and a device of this type. More specifically / in this prior document, the arrival of oxidizing gas from the apparatus is provided with means intended to keep naphthalene in solid form therein so that the oxidizing gas is charged with it by direct transformation of the naphthalene from its solid phase into a gas phase, process which will be called "sublimation" in the present description. In a preferred version of the device described in the aforementioned document, the means for maintaining the naphthalene in the gaseous oxidant stream are formed by a cartridge placed in a filter placed in the conduit for supplying oxidant gas to the device. For example, if the appliance is an internal combustion engine or a burner supplied with a fuel formed from hydrocarbons, the means for maintaining the naphthalene are placed in the air filter of the appliance in question.

The aforementioned document also specifies that the quantity of naphthalene is chosen at a value which does not exceed 5 gs per liter of oxidizing gas sent to the device. However, thanks to numerous tests carried out by the Applicants, it has been found that the indicated proportion of naphthalene does not lead to the desired effect of improving combustion.

The object of the present invention is to propose a method and a device for improving combustion which are improved compared to those described in the prior art which has just been briefly analyzed above, and in particular to indicate the effective volume proportions of sublimable compound relative to the volume of oxidizing gas to be used.

It therefore relates to a method for improving the combustion of fuels in devices in which a mixture of a fuel and an oxidizer is burned to provide energy by which a solid organic compound is sublimed in a current of oxidizing gas before it is mixed with a fuel, the resulting mixture then being burned to provide energy, characterized in that the sublimated volume proportion of said organic compound relative to the volume of oxidizing gas forming part of said mixture, is located in a range from 0.5 ppm to 15 ppm. According to the invention, the volume proportion of the sublimable organic compound can therefore be lower by several orders of magnitude compared to the proportion which has been indicated in the prior art. Furthermore, tests have shown that outside the range of values indicated, the combustion improvement effect is zero. As a result, the quantity of sublimable organic compound consumed by the process according to the invention is very much lower than the consumption estimated previously. According to other characteristics of the process of the invention: in the case where it is implemented in an internal combustion engine, said range is from 0.5 ppm to 2.5 ppm, preferably from 1.2 ppm to 1.5 ppm; - in the case where it is used in an industrial burner, said range is from 5 ppm to 15 ppm;

The tests carried out by the Applicants have also shown that naphthalene is not the only sublimable substance which is suitable for the implementation work of the invention. Consequently, according to other characteristics of the process of the invention: said organic compound is chosen from polycyclic aromatic compounds, polycyclic alicyclic compounds, functionalized aromatic compounds, functionalized alicyclic compounds, aromatic or aliphatic acids and / or mixtures of these compounds; said sublimable compound is chosen from the group of compounds consisting of naphthalene, anthracene, cuban, adamantane, camphane, naphthols, anthraquinone, camphor, or mixtures of these compounds; said sublimable compound is naphthalene, adamantane and / or camphane; the sublimable compound (s) are used in the form of tablets obtained by compacting their powders; said tablets contain only one compound selected from said group of compounds; said tablets contain at least two compounds chosen from said group of compounds.

The invention also relates to an oxidizer filter for implementing the method as defined above, comprising a casing having an inlet and an outlet for oxidant gas and, interposed between this inlet and this outlet, an element of filtering, the filter also comprising a cartridge disposed downstream of said filtering element with respect to the flow of oxidizing gas passing through it, said cartridge comprising perforated tubes in which the sublimable organic compound is disposed, said filter being characterized in that said cartridge comprises at least one strip-shaped support member having undulations enclosing said tubes, preferably by elastic effect.

Thanks to this particular characteristic of the filter according to the invention, the structure of the cartridge in strips induces a minimum pressure drop vis-à-vis the oxidant current passing through the filter.

According to other characteristics of this filter according to the invention: said filtering element being of generally cylindrical and annular shape, said support member in the form of a band is elastic and shaped like a C, the branches of which are stressed outwards and in that this support member is held in said filtering element by applying said strip against its inner wall; each branch of said strip extends towards the inside of the C by a corrugated portion to which is fixed a lamella also corrugated so as to provide with said strip passages for fixing said tubes; said filter element having an essentially flat shape, said strip-shaped support member comprises two corrugated strips fixed to one another so as to delimit passages for said tubes, said cartridge being disposed directly against said filter element , preferably by resting thereon by gravity; each tube is devoid of perforations over a part of its length in order to contain a reserve of sublimable organic compound; said tablets can be stacked in said tubes and urged by a spring disposed at one end of the stack of tablets; said strip-shaped support member has omega-shaped corrugations in which said tubes are caught by clipping.

The particular characteristics of the filter which have just been defined bring in particular the following advantages:

The fixing of the tubes containing the sublimable organic compound by corrugated strips allows easy mounting of the tubes in the cartridge. - The quantity of compound placed in the filter can be easily adjusted by choosing the number of tubes fixed in the corrugated bands. This represents an advantageous convenience for the user, even a non-professional user, because he will not only be able to replace the used filters himself, but also without difficulty adapting the cartridge to the device with which the filter is associated.

For example, if the filter is mounted on a motor vehicle engine, it can thus easily be adapted to the engine displacement, in particular at the time when the cartridge is sold in the retail trade. Furthermore, an adaptation to the shape of the filter can be carried out without problems by adequately positioning the tubes with respect to the filter inlet and outlet. - The structure of the cartridge is such that the tubes are released from the filter element and as regards the cylindrical configuration envisaged, it places the tubes at the center of the oxidant flow.

Other characteristics and advantages of the invention will become apparent during the description which follows, given solely by way of example and made with reference to the appended drawings in which: FIG. 1 shows in axial section view, a filter oxidizer used upstream of the collector suction of an internal combustion engine, the filter being provided with a charge of sublimable organic compound; Figure 2 is a radial sectional view of the filter of Figure 1, along the section line II-II; Figure 4 is a vertical sectional view of a flat filter usable as the filter of Figure 1 and also loaded with a sublimable organic compound; Figure 5 is a plan view of the filter of Figure 4 with its cover removed; FIGS. 6 and 7 show two alternative embodiments making it possible to fix tubes filled with sublimable organic compound in a filter according to FIGS. 1 to 3 or 4 and 5.

Figures 1 to 3 show a first embodiment of a filter for implementing the method according to one invention.

It is an oxidizer filter 1 for an internal combustion engine comprising a casing 2 closed by a cover 3, the whole being of generally cylindrical shape. The casing 1 has a lateral inlet orifice 4 intended to be connected to an outlet (not shown) for oxidizer, air for example. It also has an axial outlet orifice 5 intended to be connected to the suction manifold (also not shown) of an internal combustion engine.

An annular filter element 6 of conventional shape and texture is disposed axially in the filter while being held by any suitable means.

The filter 1 also contains a cartridge 7 containing a sublimable organic product. This cartridge 7 comprises two supports 8a and 8b placed inside the filter element 6 at a certain distance from each other along the axis of the filter. Each of these supports comprises an elastic band 9 curved in the shape of a C, the elasticity is such that the ends of the C tend to deviate from one another. Consequently, to place such a support inside the filtering element 6, it is advisable to bring its ends closer to each other, to introduce the support into it, then to release the ends so that the branches of C come to bear under elastic stress against the filter element 6. This results in a very convenient assembly / disassembly of the cartridge 7 requiring no tools. This arrangement is particularly suitable for making it convenient to replace a used cartridge with a full cartridge.

Beyond the ends of the C-shaped part of the strip 9, the latter is folded inwards and shaped so as to have corrugated parts 10a, 10b and 10c, the vertices of which are oriented laterally towards the outside. Each of these corrugated parts is doubled by a corrugated part (11a, 11b and 11b respectively) of a second strip 11, two of these strips being provided in the example described.

The associated corrugated parts 10a, 11a, 10b, 11b and 10c, lie delimit a passage 12 for a reservoir tube 13 intended to contain sublimable compound. Each of these tubes is formed of a portion of rolled sheet metal the longitudinal edges of which are not contiguous, thus delimiting a longitudinal slot 14 (FIG. 3). The rolled sheet is closed at each end by a plug 15, preferably tamper-proof. Furthermore, it is perforated to form rows of holes 16 located on generators which are spaced 90 ° from each other and relative to the slot 14, respectively. Note, however, that these rows of holes do not extend over the entire length of the tubes, the portion corresponding to a distance d from each tube devoid of holes being, in the example described, in the part of the filter located beyond the inlet 4 relative to the outlet 5. The reason will be explained below. Preferably, the apparent surface of the slot 14 is equal to the cumulative apparent surface of a row of holes 16.

Before being sealed, each tube 13 is filled with solid pellets 17 of the sublimable organic product, each pellet having a diameter slightly less than the inside diameter of the tube. The pellets 17 are stacked in the tube 13 and supported on each other by means of a spring 18 provided inside the tube at one end of the latter. Therefore, we understand the reason for the portion of each tube devoid of holes. It can indeed serve as a reservoir of dumplings, those which are not started by sublimation as long as they have not descended towards the perforated portion of the tube after partial or total consumption of the pellets housed in this perforated portion . It should be noted in this regard that the oxidant current in the filter is mainly established in a zone located between the inlet 4 and the outlet 5 of the filter.

(in the example the lower zone), the remainder of the filter volume being traversed by an oxidant current having a lower flow rate. The location of the section devoid of holes in each tube therefore preferably coincides with this remaining volume swept by a weak oxidant current.

The total area of the holes 16 and of the slot 14 cumulated for all the tubes 13 determines the rate of sublimation of the sublimable compound when it is swept by the current of oxidant penetrating into each tube and leaving loaded with a certain proportion of compound gorgeous. This total surface is chosen in such a way that, taking into account in particular the flow of oxidizing gas passing through the filter, the proportion of compound sublimed in the gas stream leaving the filter through the outlet orifice 5 is between 0.5 ppm and 2.5 ppm, maximum efficiency can be obtained, if this surface fixes the proportion between 1.2 and 1.5 ppm. In the case of naphthalene, 1 ppm by volume of sublimed product corresponds to 5.71 mg of naphthalene per m ³ of oxidizing gas such as air.

According to the combustion improvement process implemented using the oxidant filter that has just been described, the organic compounds must sublimate between -15 ° C and + 80 ° C and they can be chosen from polycyclic aromatic compounds, polycyclic alicyclic compounds, functionalized aromatic compounds, functionalized alicyclic compounds, aromatic or aliphatic acids and / or mixtures of these compounds. It has been found that the following compounds are particularly suitable: naphthalene, anthracene, cuban, adamantane, camphane, naphthols, antraquinone, camphor. It is also possible to use a mixture of two or more of these products. Currently, however, naphthalene, adamantane and camphane are preferred products.

It is also advantageous to package the sublimable organic compound (s) in the form of tablets obtained by compacting a powder of the concerned compound (s). The shape of the tablets will be adapted to the support intended to keep them in the flow of oxidizing gas. We have previously seen that pelleted tablets adapt well in an oxidizer filter such as as described above. However, other shapes are possible such as sticks, pastilles etc.

The filter described above in connection with FIGS. 1 to 3 was mounted on a diesel engine on a test bench, the engine having first undergone tests, while the filter was devoid of the cartridge 7, then the same tests were carried out while this cartridge was in place as shown in FIGS. 1 to 3. During the two test sessions, the parameters were successively measured, at full load, at idle and during transient phases of engine operation. following for three different sublimable organic compounds, these compounds being respectively, naphthalene, adamantane and camphane: - Torque supplied by the engine;

Specific fuel consumption; CO content of exhaust gases; Content of unburnt hydrocarbons in exhaust gases; - Opacity of exhaust gases

NOx content of exhaust gases. The values of these parameters were measured and the percentage change in the values recorded during the first test session was noted compared to the equivalent values in the second session.

In addition, the transient phases were examined by taking averages of the values measured during successive rises from idle to 4000 rpm, with steps every 500 rpm for one hour.

The results of this comparative study appear in the following table: BOARD

In this table, the dashes mean that the corresponding value was not measured or was not measurable.

It can thus be seen that the use according to the invention of the sublimable organic compound leads to a reduction in fuel consumption and a considerable improvement in the parameters determining the pollution by the exhaust gases of the engine.

Figures 4 and 5 show another oxidizing gas filter 1A having a parellélépipédique shape. The casing 2A of this filter comprises a cover 3A, a side inlet 4A of oxidizing gas and an outlet 5A provided in the cover 3A. The cartridge 7A of sublimable organic compound is shaped analogously to that described in connection with FIGS. 1 to 3, except that the band 9A is not elastic and developed in a plane resting by gravity on the filtering element 6A. The cartridge comprises tubes 13 similar to those already described. Only three of these tubes being represented. Note, however, that they have holes over their entire length and have no spring. Furthermore, in a space close to the entry 4A, there are no tubes, this in order to guarantee a sublimation as uniform as possible of the compound.

Figure 6 shows a variant of fixing the tubes 13 in the filter. These are taken elastically between two wavy bands 19 suitably fixed to the wall of the filter. FIG. 7 shows another variant of attachment in which the tubes 13 are clipped into housings 20 in the form of an omega of a band 21, the latter being suitably fixed in the filter housing. Tests carried out on industrial burners which can be used in particular in central heating installations have also demonstrated the effectiveness of the process according to the invention. It has been observed that, compared to a burner not equipped with an oxidizer filter according to the invention, an equipped burner can reduce its consumption by up to 22%, that the sulfur emissions were eliminated, the NOx decreasing by 50% and the opacity being also reduced by 50%.

In the case of industrial burners, a filter is not usual. It is therefore possible to have a cartridge of sublimable organic product directly in the oxidant gas supply pipe. In this case, the proportion of sublimable organic compound is preferably situated in a range going from 5 ppm to 15 ppm depending on the type of burner equipped.

Claims

1. Method for improving the combustion of fuels in devices in which a mixture of a fuel and an oxidizer is burned to provide energy by which a solid organic compound is sublimed in a stream of oxidant gas beforehand to its mixture with a fuel, the resulting mixture then being burned to provide energy, characterized in that the sublimated volume proportion of said organic compound relative to the volume of oxidizing gas forming part of said mixture, lies in a range from from 0.5 and 15 ppm.

2. Method according to claim 1, characterized in that, in the case where it is used in an internal combustion engine, said range is from 0.5 ppm to 2.5 ppm, preferably 1.2 ppm at 1.5 ppm.

3. Method according to claim 1, characterized in that, in the case where it is used in an industrial burner, said range is from 5 ppm to 15 ppm.

4. Method according to any one of claims 1 to 3, characterized in that said organic compound is chosen from polycyclic aromatic compounds, polycyclic alicyclic compounds, functionalized aromatic compounds, functionalized alicyclic compounds, aromatic or aliphatic acids and / or mixtures of these compounds.

5. Method according to claim 4, characterized in that said sublimable compound is chosen from the group of compounds consisting of naphthalene, anthracene, cuban, adamantane, camphane, naphthols, antraquinone, camphor , or mixtures of these compounds.

6. Method according to claim 5, characterized in that said sublimable compound is naphthalene, adamantane and / or camphane.

7. Method according to any one of claims 1 to 6, characterized in that the sublimable compound or compounds are used in the form of tablets obtained by compacting their powders.

8. Method according to claim 7, characterized in that said tablets contain only one compound chosen from said group of compounds.

9. Method according to claim 7, characterized in that said tablets comprise at least two compounds chosen from said group of compounds.

10. Oxidizing filter for implementing the method according to any one of the preceding claims, comprising a casing having an inlet and an outlet for oxidizing gas and, interposed between this inlet and this outlet, a filtering element, the filter. also comprising a cartridge disposed downstream of said filtering element with respect to the stream of oxidizing gas passing through it, said cartridge comprising perforated tubes in which the sublimable organic compound is disposed, said filter being characterized in that said cartridge comprises at least one member of support in the form of a band having undulations enclosing said tubes, preferably by elastic effect.

11. Filter according to claim 10, wherein said filter element is of generally cylindrical and annular shape, characterized in that said support member in the form of a strip is elastic and shaped like a C, the branches of which are biased towards the outside. and in that this support member is held in said filter element by applying said strip against its inner wall.

12. Filter according to claim 11, characterized in that each branch of said strip extends towards the inside of the C by a corrugated portion to which is fixed a lamella also corrugated so as to provide with said strip passages for fixing said tubes.

13. Filter according to claim 10, wherein said filter element has an essentially flat shape, characterized in that said strip-shaped support member comprises two corrugated strips fixed to each other so as to delimit passages for said tubes, said cartridge being disposed directly against said filter element, preferably resting thereon by gravity.

14. Filter according to any one of claims 10 to 13, characterized in that each tube is devoid of perforations over at least part of its length in order to contain a reserve of sublimable organic compound.

15. Filter according to claim 13 for the implementation of the method according to any one of claims 7 to 9, characterized in that said tablets are stacked in said tubes and biased by a spring disposed at one end of the stack of tablets.

16. Filter according to any one of claims 10 and 11, characterized in that said strip-shaped support member has omega-shaped corrugations in which said tubes are caught by clipping.