ADDITIVES DESIGNED TO IMPROVE FUEL QUALITY IN RECIPROCATING INTERNAL COMBUSTION ENGINES

Abstract: The object of the present patent finds application in the field of fuels and internal combustion piston engines. The additives here considered consist of metallorganic compounds or solutions of metal salts, which, through thermic decomposition during the normal functioning of the engine, are transformed into ionic solids with the hexaoctahedric structure of the spinel, of the inverted spinel with the disordered structures of the spinel or garnet. They facilitate a particular type of fixed-bed hydrogenating catalytic cracking which works through solid-gas surface catalysis inside the combustion chamber during the normal functioning of the engine. These ionic solids perform the dual function of promoting hydrogenating catalytic cracking at low temperature and acting as combustion catalysts at high temperature; both these conditions obtain in the combustion chamber at every explosion.

Description: Additives designed to improve fuel quality in reciprocating internal combustion engines. Technical Field The object of the present Patent can be applied to the field of fuels and internal combustion piston engines. Background Art The functioning of piston engines, both ignition and diesel, is based on combustion. Under the broad term of combustion there are actually many chemical reactions that occur and overlap, discharging energy in a way that is apparently chaotic but in fact conditioned by temperature, pressure, the state of the matter, type of fuel, quantity of comburent and, last but not least, the possible presence of positive and negative catalysts. Combustion is not always perfect, however, and engines tend to detonate and to discharge unburnt gases. Many improvements have been achieved in recent years in engine studies as well as in chemistry, additives, fuels and afterburning catalysis in order to solve these shortcomings. In particular, in order to inhibit detonation, metallorganic compounds (lead, manganese, etc.) have been used in relatively large quantities to produce a detonation-inhibiting catalysis. In other words, these compounds reduce the combustion speed in the combustion chamber. The present state of technical knowledge includes a catalysed chemical process for use in reciprocating internal combustion engines to improve fuel quality, filed as an Italian Patent Application by the applicant for the present Patent on July 4th 1994 with Report No. TS94A000007. The aforementioned Patent application describes a catalysed chemical process consisting in a particular fixed-bed hydrogenating catalytic cracking process by means of solid-gas surface catalysis taking place within the combustion chamber during the normal running of the engine. This process transforms high-boiiing hydrocarbons into low-boiling hydrocarbons with a consequent increase in the octane number. The pressure increase caused by the combustion itself is exploited to split the hydrocarbon molecules. Without the catalysts described in the Patent Application the combustion would cause a detonation. This cracking process uses as a support for the catalysts the carbon deposits usually found in the combustion chamber and on the inner walls of exhaust pipes. The catalysts used consist of spinel structured double or mixed metal oxides derived from the thermic decomposition of metallorganic compounds added to fuel. These oxides perform the dual function of promoting low- temperature hydrogenating catalytic cracking and acting as combustion catalysts at high temperature. Both these conditions occur in the combustion chamber at every explosion - low temperature at the beginning of mixture ignition, high temperature as combustion progresses. A part of the oxides, leaving the cylinder together with the exhaust gases, permeates the deposits covering the inner walls of the exhaust pipes, transforming the deposits into a catalytic discharge which further reduces the quantity of unburnt gases. The precursors of "process catalysts" are metallorganic compounds which on thermic decomposition form spinel-structured double and mixed oxides of iron, cobalt and nickel. Disclosure of Invention The purpose of the present invention is to make available to consumers a further series of catalyzers able to exploit the chemical process described in the aforementioned Patent Application No. TS94A000007. Another purpose is to improve fuel at the moment of combustion, reducing detonation and catalyzing the complete combustion to CO2 and H2O. These and other purposes are achieved by the present invention, which concerns a series of additives to be added to fuels or introduced into the combustion chamber, exploiting the above-mentioned chemical process. These additives are made up of metal salts in solution or metallorganic compounds that, with the high pressures and temperatures developed in the combustion chamber while the engine is running, through pyrolysis form ionic solids with the hexahoctahedric spinel structure, inverted spinel or disordered spinel structures formed by the double or mixed oxides of the various metals. As the catalyzers are formed by double or mixed metal oxides, below is a list of metal groups that, in the appropriate proportions, form ionic solids with the hexahoctahedric spinel and sometimes garnet structure (the crystals are obviously real and therefore not perfect). One exception is cobalt which, if used alone, tends to form hexagonal lattices that have less resistance at running temperatures. 1) aluminium manganese 20-40 50-80 2) aluminium manganese copper 20-30 60-70 2-10 3) aluminium manganese chrome 20-40 40-70 10-20 4) aluminium manganese chrome zinc 20-30 40-60 7-15 1-5 5) aluminium manganese molibdenurr 1 20-40 40-70 10-20 6) aluminium iron magnesium 15-25 40-70 15-25 7) aluminium cobalt copper iron nickel titanium 5-10 30-45 1-5 20-35 10-20 5-10 8) aluminium cobalt chrome iron magnesium 10-25 25-45 5-20 15-25 10-25 9) barium iron 10-20 80-90 10) bismuth manganese 70-90 10-30 11) cerium cobalt 20-30 50-70 12) cerium cobalt rare cerium earth 20-30 55-70 5-15 13) yttrium cobalt rare yttrium earth 15-25 65-85 2-15 14) cobalt yttrium 65-85 15-35 15) cobalt iron lead 5-20 5-25 65-75 16) cobalt iron 30-70 30-70 17) cobalt iron vanadium 40-65 40-60 2-20 18) cobalt iron chrome 5-40 40-75 2-40 19) iron copper nickel chrome 10-20 3-8 60-85 1-5 20) cobalt iron chrome wolfram 30-40 35-65 1-10 1-10 21) cobalt platinum 20-30 70-80 22) cobalt praseodymium 60-70 30-40 23) cobalt samarium 60-70 30-40 24) cobalt chrome 20-80 20-80 25) cobalt cchhrroommee iron magnesium 30-40 55--1155 15-25 15-25 26) copper iron 30-40 60-70 27) iron lithium 90-98 2-10 28) iron magnesium 75-90 10-25 29) iron strontium 85-95 5-15 30) iron manganese 55-80 25-45 31) iron silicon 90-98 2-8 32) iron nickel 60-70 30-40 33) iron molibdenum 40-70 25-40 34) cobalt iirroonn molibdenum 40-60 1155--3300 10-30 35) cobalt 100 It makes no difference whether the metals are introduced into the combustion chamber in the form of fuel-soluble metallorganic compounds or salts of the various metals in aqueous solution, in the latter case introduced together with the induction air by means of a nebulizer. Metallorganic compounds are preferable, however. Each group of metals in the list has its own catalytic properties, but it is possible to mix groups together to obtain compromises between the various reactions. The quantities of metals contained in the fuel additives vary from 0.5 to 10 grammes per 1 ,000 litres of fuel. The attributes of the catalyzers used are: - they have the properties of magnetic materials; - excellent resistance to temperatures and pressures and the gas movements occurring in the combustion chamber when the engine is running; - the ability to form a chemical bond with the carbon in the deposits normally present in the combustion chamber and in exhaust pipes; - they are effective in very low quantities. The catalyzers in question have the characteristic of not being poisoned by the presence of water vapour, nitrogen, sulphur, calcium, sodium, potassium, etc. Indeed, these substances seem to facilitate the reactions of the process. The catalyzers are also able to promote the cracking of the hydrocarbons inside the combustion chamber, catalyze the hydrogenation of the olefines (alkenes) produced by the cracking at the expense of the humidity of the comburent air, which is used as H-OH ions, and facilitate the complete combustion of fuel and comburent to CO2 and H2O. As described above, the chemical process for which protection has been requested in Italian Patent Application No. TS94A000007 exploits the coked carbon deposits covering the inside of the combustion chamber (piston head and crown) and the inside of the exhaust pipes. These deposits have a micropore structure with a high specific surface, which makes them an ideal support for "process catalysts". During the functioning of the engine, that is to say at every explosion, the metal oxides derived from the additives in question are thrown and pressed on to the deposits, penetrate the pores and, since the deposits are almost incandescent, some oxides form a chemical bond with the carbon in the deposits, settling there permanently. The result is a catalytic bed able to promote heterogenous-phase solid/gas reactions. In view of the fact that metal oxides give rise to bunching, it is extremely important that the quantity of catalyzing oxides is not so great as to obstruct the deposit pores or even form syπtherisations. It is thus advisable to add to the fuel additives whose total metal content is less than ten grammes per 1,000 litres of fuel. In the combustion chamber a process similar to "fixed-bed hydrogenating catalytic cracking" takes place by means of solid-gas surface catalysis. This cracking reaction occurs at every explosion in a few dozen microseconds between the combustion induction time, or "cool flame moment", when the pressure is high but the temperature is not yet high. It is at the cool flame moment that, thanks to surface catalysis, the energy flow of combustion is modified. It is at this moment that the high-boiling hydrocarbon molecules are split and transformed into low-boiling molecules. From this moment occurs the hydrogenation of the alkenes formed during the cracking at the expense of the induction air which is used as H-OH ions. This system works with all types of piston engines: 2 and 4 stroke, petrol, oil or diesel. Depending on the type of additive or additive mix the following results may be obtained: 1) decrease in polluting exhaust gases (especially particled and HC); 2) significant increase in Octane-Road Number in petrol and oil engines; 3) increase in LIB number in petrol engines; 4) decrease in pre-ignitions (rumbling) in oil and diesel engines; 5) the cetane number in diesel engine fuels is not modified; 6) slight increase in engine power according to the degree of humidity of the induction air and its ionization; 7) with some catalysts the engine is more responsive and flexible if the temperature in the cooling system is 10-15 degrees lower than the running temperature; 8) the stoichiometric fuel-air ratio is modified, the mixture is richer, especially when the engine is cold (only for engines with carburettors); 9) in petrol engines the average running temperature is lower, which allows the fitting of hotter sparking plugs; 10) the lambda probe is not affected by the catalysts; 11) most of the catalytic oxides do not damage the traditional catalytic muffler, but are in synergy with it. Mode for Carrying Out the Invention Below are some examples of metal groups usable as catalysts in this invention. It is to be understood that in the examples, a preferred but not exclusive list of possible metal groups, the proportions between the groups are indicative only and do not constitute limits to the present invention: 1) aluminium manganese 30 70 2) aluminium manganese copper 28 70 2 3) aluminium manganese chrome 30 60 10 4) aluminium manganese chrome zinc 28 60 10 2 5) aluminium manganese molibdenum 30 60 10 6) aluminium iron magnesium 18 65 17 7) aluminium cobalt copper iron nickel titanium 8 38 3 29 14 8 8) aluminium cobalt chrome iron magnesium 18 35 10 20 17 9) barium iron 15 85 10) bismuth manganese 80 20 11) cerium cobalt 34 66 12) cerium cobalt rare cerium earth 25 65 10 13) yttrium cobalt rare yttrium i earth 20 75 5 14) cobalt yttrium 75 25 15) cobalt iron lead 10 18 72 16) cobalt iron 65 35 17) cobalt iron 50 50 18) cobalt iron vanadium 49 49 2 19) cobalt iron chrome 33 64 3 20) iron copper nickel chrome 16 5 77 2 21) cobalt iron chrome wolfram 36 56 4 4 22) cobalt platinum 24 76 23) cobalt praseodymium 66 34 24) cobalt samarium 66 34 25) cobalt chrome 60 40 26) cobalt chrome iron magnesium 50 10 20 20 27) copper iron 34 66 28) iron lithium 95 5 29) iron magnesium 83 17 30) iron strontium 92 8 31) iron manganese 65 35 32) iron silicon 96 4 33) iron nickel 66 34 34) iron molibdenum 65 35 35) cobalt iron molibdenum 60 17 23 36) cobalt 100 The percentage weights of the metals present in the various metal salts or metallorganic compounds that may be used are calculated. On the basis of this result it is possible to calculate the quantities in grammes of compounds or salts to be added to fuel. Example: 1 gramme of lead tetraethyl contains 0.603 grammes of lead, 1 gramme of ironcene contains 0.301 grammes of iron, 1 gramme of aluminium isopropylate contains 0.313 grammes of aluminium; the quantity to be added to fuel varies from 0.5 to 10 grammes of metals per 1 ,000 litres of fuel. If it felt that the discharge into the environment of even minimal quantities of ionic solids should be prevented, a permanent-magnet magnetic trap may be fitted to the end of the exhaust pipe. The particles will be intercepted because they are magnetic material.

Claims: Claims 1 - Additives designed to improve the quality of fuel for reciprocating internal combustion engines, already described in the Italian Patent Application filed by the same applicant on July 4th 1994, Report No. TS94A000007, consisting in a particular process of fixed-bed hydrogenating catalytic cracking through solid-gas surface catalysis occurring inside the combustion chamber during the normal functioning of the engine; this process transforms high-boiling hydrocarbons into low-boiling hydrocarbons with a consequent increase in the octane number; the cracking process uses as support for the catalysts the carbon deposits usually found inside the combustion chamber and on the inner walls of the exhaust pipes; the additives are characterised by having the properties of magnetic materials and consisting of metallorganic compounds or metal salt solutions which, through thermic decomposition during the normal functioning of the engine, are transformed into ionic solids with hexahoctahedric spinel structure, inverted spinel structure or disordered spinel or garnet structures; these ionic solids perform the dual function of promoting hydrogenating catalytic cracking at low temperature and acting as combustion catalysts at high temperature; both these conditions obtain in the combustion chamber at every explosion; furthermore, a part of these oxides, leaving the cylinder with the exhaust gases, permeates the deposits covering the internal walls of the pipes, thus transforming the pipes into a catalytic exhaust which further reduces the quantity of unburnt gases. 2 - Additives designed to improve fuel quality, according to the previous claim, characterised by the fact that they may be used in extremely limited quantities since, because the metal oxides give rise to bunching, large quantities of catalyzing oxides could obstruct the pores of the deposits or even form syntherizations; the quantities of metals contained in the additives varies from 0.5 to 10 grammes per 1,000 litres of fuel. 3 - Metal catalysts, according to the previous claim, characterised by the fact that they may be used in groups of metals, provided that they are used in the proportions necessary to form ionic solids with hexahoctahedric spinel structure and sometimes garnet structure, of which a preferential list is shown below: 1) aluminium manganese 20-40 50-80 2) aluminium manganese copper 20-30 60-70 2-10 3) aluminium manganese chrome 20-40 40-70 10-20 4) aluminium mangane se chrome zinc 20-30 40-60 7-15 1-5 5) aluminium manganese molibdenum 20-40 40-70 10-20 6) aluminium iron magnesium 15-25 40-70 15-25 7) aluminium cobalt copper iron nickel titanium 5-10 30-45 1-5 20-35 10-20 5-10 8) aluminium cobalt chrome iron magnesium 10-25 25-45 5-20 15-25 10-25 9) barium iron 10-20 80-90 10) bismuth manganese 70-90 10-30 11) cerium cobalt 20-30 50-70 12) cerium cobalt rare cerium earth 20-30 55-70 5-15 13) yttrium cobalt rare yttrium earth 15-25 65-85 2-15 14) cobalt yttrium 65-85 15-35 15) cobalt iron lead 5-20 5-25 65-75 16) cobalt iron 30-70 30-70 17) cobalt iron vanadium 40-65 40-60 2-20 18) cobalt iron chrome 5-40 40-75 2-40 19) iron copper nickel chrome 10-20 3-8 60-85 1-5 20) cobalt iron chrome wolfram 30-40 35-65 1-10 1-10 21) cobalt platinum 20-30 70-80 22) cobalt praseodymium 60-70 30-40 23) cobalt samarium 60-70 30-40 24) cobalt chrome 20-80 20-80 25) cobalt chrome iron magnesium 30-40 5-15 15-25 15-25 26) copper iron 30-40 60-70 27) iron lithium 90-98 2-10 28) iron magnesium 75-90 10-25 29) iron strontium 85-95 5-15 30) iron manganese 55-80 25-45 31) iron silicon 90-98 2-8 32) iron nickel 60-70 30-40 33) iron molibdenum 40-70 25-40 34) cobalt iron molibdenum 40-60 15-30 10-30 35) cobalt 100 these different groups of metals can be mixed together to obtain compromises among the various reactions. 4 - Additives, according to the previous claims, characterised by the fact that they may be introduced into the combustion chamber in the form of fuel- soluble metallorganic compounds and in the form of salts of the various metals in aqueous solution, the latter introduced together with the induction air by means of a nebulizer. 5 - Additives, according to the previous claims, characterised by the fact that the ionic solids used have properties which enable them to remain unaffected by the pressures and temperatures occurring inside the combustion chamber; some of these ionic solids have the property of forming chemical bonds with the carbon of the deposits, thus constituting a basis upon which other oxides will fix; the way in which they are anchored and the great stability of the catalysts make it possible to limit the quantities of metallorganic additives to the minimum required to replace particles of catalyzed deposits which have been mechanically and chemically eroded

Inventors: MARCON PIERGIORGIO, MARCON, PIERGIORGIO
Applicants: MARCON PIERGIORGIO, MARCON, PIERGIORGIO
Application year: 1995
Main classification: C10G47
IPC codes: C10G47, C10L1, C10L10