Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
  • C10L1/00—Liquid carbonaceous fuels
  • C10L1/02—Liquid carbonaceous fuels essentially based on components consisting of carbon, hydrogen, and oxygen only
  • C10L1/023—Liquid carbonaceous fuels essentially based on components consisting of carbon, hydrogen, and oxygen only for spark ignition
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B41/00—Engines characterised by special means for improving conversion of heat or pressure energy into mechanical power

Definitions

• This invention relates to new automotive gasolines having intermediate carbon ranges, and their improved use in internal combustion engines.
• the invention relates to new gasoline for use in improved gasified carburetion systems.
• Rei Vapor Pressure is the accepted measurement of gasolin volatility and it represents the vapor pressure at 100° (37.78°c).
• current fuels require a relatively high amoun of volatile components which raises the Reid Vapor Pressur to undesirable levels. It is highly desirable to formulat a fuel which satisfies the volatility requirements withou raising the Reid Vapor Pressure to the undesirable leve found in the prior art fuels.
• Present day gasoline also contains, in addition to the volatile light-weight and the intermediate-weight components, a heavy-weight component which, like the volatile component, is also associated with several disadvantages.
• the gasoline of today when used as a fuel in present day short stroke engines, results in incomplete combustion because there is insufficient time or temperature to burn the heavy hydrocarbon components. This results in a certain amount of gasoline being wasted and this contributes to pollution.
• Conventional C 4 -C 12 has too much energy in it for conventional internal combustion engines in that if combusted with enough air (stoichiometric or slightly above) it will burn too hot for the engine or it will produce high levels of nitrous oxides.
• the heavy components are left in present day fuel because their presence is considered necessary to provide a fuel having suitable properties for automotive use.
• the ideal combustion mixture for internal combustion engines consists of gasoline in the vapor or gaseous state thoroughly mixed with adequate air to support combustion. In this condition, fuel-rich pockets, which are responsible for detonation or "knock,” are eliminated and carbon deposits responsible for preignition are minimized due to more complete combustion. Because detonation or preignition can damage or ruin an engine, current gasolines have octane boosters such as aromatics contained therein to reduce "knock" since current engines have fuel and air intake systems which produce droplets of fuel that contribute to fuel rich pockets in the combustion chambers of the engines. Slowing the burn with octane boosters lowers the combustion efficiency of the engine and increases the exhaust pollution. Therefore, it would be highly desirable to provide a fuel which avoids octane boosters, is rated at a lower octane value but which has highly desirable burning characteristics so that the fuel does not produce engine knock.
• R represents the research octane number and M represents the motor octane number
• current engines generally require an average octane number in excess of 85.
• a primary object of this invention is to provide an improved gasoline which facilitates the achievement of ideal combustion mixtures for internal combustion engines.
• Another object of this invention is to provide a lower octane fuel and method of use so as to further improve the combustion efficiency of the fuel in an internal combustion engine.
• a further object of this invention is to provide a method whereby greater combustion efficiencies can be achieved in engines.
• the objects of the present invention are achieved b the discovery that front-end priming of gasoline is no necessary in gasifier type carburetors and that the heavie components in gasoline are not stable as gases in air usin gasifier type carburetors. Therefore it was possible t develop new intermediate hydrocarbon range gasolines tha have unique benefits not obtained in c 4 -c 12 gasoline. in addition the new gasification methods have distinct advantages over the prior art.
• One aspect of the invention relates to a gasoline having an intermediate hydrocarbon range relative to conventional C 4 -C 12 gasoline which contains C 4 , C 5 , C 6 , C 7/ c 8 , c 10 , c-n and c 12 hydrocarbons.
• the intermediate range gasoline is made by removing the lighter volatile component as well as the heavier component from a conventional gasoline starting material.
• the resulting fuel is C 6 -C 10 ; i.e. the hydrocarbons are limited to those in the range C 6 -C 10 .
• Suitable starting material to produce the gasoline of this invention is conventional gasoline having a range of C 4 -C 12 .
• Both the heavy and light components are removed by any of the known methods currently available such as heat fractionization or the use of heat and vacuum in the absence of air. Once removed, the heavy component may be "cracked" at the refinery to make more gasoline and the volatile component, most of which is being wasted today, may be fully recovered at the refinery.
• gasoline having a range of C 4 -C 12 is mentioned as a useful starting material, it is not critical that the starting material be precisely in this range. Rather, it is the essence of this invention to produce a gasoline fraction of intermediate carbon range relative to the given range C 4 -C 12 that may be produced directly from refinery hydrocarbon streams.
• the presen invention also provides an improved fuel for use in car having standard carburetion systems.
• the above described C 6 -C 1 and C 6 -C 9 gasoline can be used in an internal combustio engine having a standard carburetion system by priming th gasoline with a minimum amount of C 4 ,C 5 or a mixture of C and C 5 to produce a gasoline having adequate front en volatility for starting cars equipped with standar carburetion systems.
• the gasoline may be primed wit c 4 and/or C 5 , then the permissible range of such a fue will be C 4 -C 9 (winter) and C 4 -C 10 (summer) .
• the amount of C 4 or C 5 primin necessary for achieving adequate front end volatility ⁇ for starting engines equipped with a standard carburetio system is less than the amount required with conventiona C 4 -C- 12 gasoline.
• this aspect of the invention provide an improved fuel for standard carbureted engines and thi fuel will advantageously contain less C 4 or C 5 tha conventional C 4 -C 12 gasoline while maintaining adequat front end volatility and reduced Reid Vapor Pressures.
• the C 6 -C 10 and C 6 -C gasoline requires les priming to achieve adequate front end volatility for starting engines equipped with standard carburetion systems than does normal C 4 -C 12 automotive gasoline.
• the amount of C 4 , C 5 or mixture of C 4 and C 5 used to prime the C 6 -C 10 or C 6 -C 9 gasoline is a minimum amount necessary to achieve adequate front end volatility for starting a car equipped with a standard carburetor.
• the C 4 -C 0 and C 4 -C 9 gasoline can also be made by removing the heavy and light components from gasoline as described above for making C 6 -C 10 and C 6 -C 9 with the exception that an adequate amount of C 4 and/or C 5 is retained in the product to achieve adequate front end volatility for starting a car equipped with a standard carburetor.
• prior art gasoline having a carbon range of C 4 to C 12 can be improved by removing the higher molecular weight constituents so as to produce a gasoline fuel having a narrower carbon range of C 4 to Cn and a boiling point range of ll ⁇ P to 38 °F (-11.7 to 195.6°C).
• a narrower range fuel facilitates both the ability of the gasoline to be vaporized or gasified as well as the ability of the vapor or gas to remain as a vapor or gas when mixed with ambient air without forming droplets which can wet the surface in an interna combustion engine.
• This narrower fuel allows idea combustion mixtures to be used in internal combustio engines and, in turn, allows lower octane gasoline to b used which further improves combustion efficiency an lowers the production of pollutants produced durin combustion.
• Prior art aviation gasoline having a carbon range o c 4 to C would not require the removal of higher molecula weight constituents to be stable as a vapor or gas i ambient air but the use of such prior art fuels woul require the lowering of the octane to increase the speed o burn, thus improving combustion efficiency and lowering th pollutants produced during combustion.
• the conversion of the fuels of this invention int vapors or gasses, homogenizing these vapors or gasses wit intake air (ambient or heated) while maintaining gas o vapor stability and combusting this fuel mixture in a engine represents an improved method for achieving highe combustion efficiency while lowering the pollutants o combustion.
• Figure 1 is a graph which illustrates the fue efficiency of selected fuels in a 1500 c.c. Albe engine at various engine speeds.
• the vertical axis show the efficiency in term of lbs. of fuel/horsepower hour
• the horizontal axis measures the engine speed.
• Figure 1 also illustrates the fuel efficiency of the gasoline of this invention combusted in an identical engine equipped with the improved carburetor of this invention.
• both the lighter volatile component and the heavier, slow-burning component are removed from gasoline in the C 4 -c 12 range.
• the removal of the volatile component makes the resultant fuel have a slower rate of burning.
• the resultant fuel is an intermediate gasoline having a burn rate comparable to or better than the starting stock gasoline (C 4 -C 12 ) from which it was made.
• the most abundant of the volatile components in conventional C 4 -C 12 gasoline is butane and pentane. With regard to the removal of the volatile components it is primarily the butane and pentane which is removed from the C 4 " C 12 gasoline in the practice of this invention. If the gasoline contains hydrocarbons lighter than butane, it is desirable that they too be removed.
• the heavy, slow-burning component consists primarily of C ⁇ and C 12 , each of which exists in numerous isomeric forms. These are removed and, if the starting stock gasoline contains hydrocarbons greater than C 12 , it is desirable that they also be removed. In both cases the light volatile components and the heavy, slow-burning components are removed according to conventional known methods.
• both components are removed, resulting in an intermediate hydrocarbon range.
• the boundaries of this range depend upon the extent to which the heavy and ligh components are removed.
• both component are substantially removed but it is recognized that som may be left behind due to imperfections in curren fractionation techniques. It is most desirable that th heavy and light components be substantially removed.
• the heavy and ligh components do not exist as absolutes but rather, as points on a continuum with the most volatile being the lighte hydrocarbons, and a gradual reduction in volatility an burning tendency as the weight is increased. This gives rise to certain "border line” components near both ends of the continuum. It is inevitable that some of these will be removed with the heavier and the lighter components. I general, it is recognized that the border line weights are C 6 and C 10 .
• the border line weights are C 6 and C 10 .
• the heavy componen is also removed in an effective amount to raise the bur rate of the fuel and effect more complete combustion. Bot of these components are removed and this fuel is used wit an improvement in fuel combustion efficiency and engin performance.
• Figure 1 shows a comparison which measure the efficiency of the fuel of the present invention versus the efficiency of conventional C 4 -C 12 prior art fuels a various engine speeds.
• the fuel efficiency is measured i terms of Brake Specific Fuel Consumption (lbs. of fuel pe horsepower hour) .
• Lower Brake Specific Fuel Consumptio values indicate better fuel efficiency.
• the C 6 -C 10 fuel of this invention may be used to run a engine equipped with the improved gasifier carbureto described herein. However, it is not necessary that volatile components be absent from the fuels used in the improved gasifier combustors since their presence in the fuel does not hinder the gasification process. Thus, some volatile C 4 and/or C 5 may be added to the C 6 -C 10 fuel so that the fuel can be used in a standard carbureted engine as well as an engine equipped with the improved gasifier carburetor. For this reason the comparison presented in Figure l utilized a C 6 -C 10 fuel containing some C 5 volatile component so that the resulting C 5 -C 10 fuel will run an engine equipped with an improved gasifier carburetor as well as a standard carbureted engine.
• the C 5 -C 10 has a boiling point range about 49 ⁇ F-345 ⁇ F (9.4 to 174°C).
• the C-C 12 gasoline is used as a starting ingredient from which the volatile C 4 and C 5 constituents and the heavy C n and C 12 components are removed.
• the starting C 4 -c 12 gasoline contains a mixture of each of the hydrocarbons (i.e. - a mixture containing C 4 , C 5 , C 6 , C 7 , c 8 , c 9 , C 10 , Cn and C 12 ) . Consequently, the intermediate C 6 -C 9 and C 6 -C 10 gasoline of the preferred embodiment will likewis contain the same intermediate hydrocarbons which ar present in the starting gasoline. In other words, C 6 -C will contain, C 6 , C 7 , C 8 , and c 9 and the C 6 -C 10 gasoline wil contain, C 6 , C 7 , C 8 , C 9 and C 10 hydrocarbons.
• the fuels of the present invention have a intermediate hydrocarbon range relative to conventiona gasoline which has a hydrocarbon range of C 4 -C 12 .
• Th conventional C 4 -C 12 gasoline contains paraffinic hydrocarbon including C 4 , C 5 , C 6/ C 7 , C 8 , C 9 , C 10 , C ⁇ and C 12 paraffini hydrocarbons.
• C ⁇ and C 12 paraffini components of the C 4 -C 12 fuel will result in a fuel whic contains paraffinic hydrocarbons, including paraffinic C and C 10 which were originally present in the C 4 -C 1 paraffinic fuel from which the fuel of this invention ma be derived.
• the C 4 -C 11 fuel should be formulated, wit or without additives, to produce a maximum Reid Vapo Pressure of less then 5 psi.
• a fuel is particularl suitable for gasifier engines or other engines havin enhanced vaporization capability.
• a full range C ⁇ c fuel has RVP whic is less than 5 psi.
• a C 4 -C fuel can be easily formulate to meet this criteria by the appropriate selection of C 4 -C 1 constituents so as to limit the RVP to less than 5 psi.
• the ligh and heavy components are removed from conventional C 4 -C 1 gasoline to produce a gasoline having a hydrocarbon rang of C 5 -C 10 .
• a fuel is identical to the C 6 -C 10 fuel wit the exception of the presence of C 5 component in the C 5 -C 1 fuel.
• the c 5 -c 10 fuel will have a boiling point rang Of about 49°F-345 ⁇ F (9.45 to 174°C) .
• the starting gasoline preferably contains the entire range of hydrocarbons from C 4 -C 12 as described above, it is not absolutely essential that all of the intermediate hydrocarbons be present in the starting gasoline. However, it is critical that the C 6 -C 9 fuel contains C hydrocarbon and the C 6 -C 10 gasoline contain C and C 10 hydrocarbon.
• the preferred intermediate range C 6 -C 10 gasoline may be defined as the portion remaining when C 4 -C 12 gasoline has removed therefrom an effective amount of lower weight volatile components to substantially reduce evaporative loss and explosion potential and effective amount of higher weight components to raise the burn rate of the remaining hydrocarbons.
• a C 6 -C 10 gasoline which has these characteristics can be made by removing the volatile and heavy components so that the remaining hydrocarbon mixture will boil within a range of about 121°F-345°F (49.4 to 174°C) at one atmosphere.
• Such a boiling point range encompasses the boiling point of the lowest boiling C 6 component and the highest boiling C 10 component.
• This property is an essential aspect of the C 6 -c 10 gasoline because the C 6 -C 10 fuel is used in a modified carburetio system in which the fuel is gasified in a heated chambe and then mixed with air for immediate combustion in a automotive internal combustion engine.
• the absence o condensed droplets allows the gasoline to burn much mor efficiently than conventional C 4 -C 12 gasoline and consequently, reduces pollution and improves engin performance.
• the final boiling point will b 345°F (174°C) and, thus, the gasoline will have the desire gasification property.
• the gasification system used for intermediat hydrocarbon range gasoline requires heating the gasoline t lower temperatures that would be required for th gasification of C 4 -C 12 gasoline. When lower temperatures ar attained, the volumetric efficiency of the air and ga mixture going into an engine is improved.
• the gasoline having hydrocarbons comprised essentiall of C 6 -C 10 hydrocarbons will have lower Reid Vapor Pressur than conventional C 4 -C 12 gasoline with functional Reid Vapo Pressures less than two. Nonetheless, the C 6 -C 10 gasolin will exhibit good ignition properties in the gaseous stat when mixed with air. It will also provide excellent engin starting ability, will have reduced explosive potential an will burn more completely than C 4 -C 12 gasoline. In addition the C 6 -C 10 gasoline will burn cooler in the engine with th modified carburetor and consequently the use of such a ' fue will result in less lubrication requirements for th engine.
• Conventional C 4 -C 12 gasoline has high Reid Vapo Pressure and the Reid Vapor Pressure can be adjuste somewhat to provide summer or winter fuels.
• the Reid Vapor Pressure can be increased by addin volatiles such as C 4 to enhance the winter performance o the conventional gasoline.
• the present C 6 -C 10 invention requires lowering the Reid Vapor Pressure by removing the C 4 and C 5 components.
• the hydrocarbon range is limited to essentially C 6 -C 10 hydrocarbons. It is therefore surprising that the c 6 -c 10 gasoline can be formulated for winter use without additional C 4 priming.
• a winter fuel can be made in the same manner as the C 6 -C 10 summer gasoline with the exception being that the C 10 component is additionally separated from the starting C 4 -C 2 gasoline along with the C 4 , C 5 , C and C 12 components to provide a fuel that when gasified will remain substantially a gas when mixed with colder air.
• the present invention also provides a winter fuel having hydrocarbons which consists essentially of hydrocarbons in the range C 6 -C .
• the C 6 -C 9 winter gasoline differs from the C 6 -C 10 gasoline only in the elimination of the C 10 component which is left in the C 6 -C 0 summer gasoline. Consequently, the winter C 6 -C 9 gasoline has a final boiling point of 303°F (15l°C) and a boiling range of about 121°F-303*F (49 to 151"C).
• the C 6 -C gasoline must contain the C 9 hydrocarbon component and preferably should contain the remaining intermediate hydrocarbons which are C 6 , C 7 , and C 8 since these are preferably present in the C 4 -c 12 gasoline.
• the C 6 -C 9 winter gasoline is burned in an engine in the same manner described above with respect to the C 6 -C 10 gasoline and enjoys the same benefits described above with respect to the C 6 -C 10 gasoline.
• the C 6 -C 10 and C 6 -C 9 gasoline is gasified by heating in a chamber in the absence of air to a temperature above the final boiling point of the gasoline.
• the c 6 -C 10 and c 6 -c 9 fuels are preferably heated to a temperature 350°F (177°C). Higher temperatures may be used but are not necessary.
• Conventional C 4 -C 12 would require a temperature of about 75° (24°C) higher to gasify and when mixed with air it wou still have the problem of forming condensation droplet Additionally, the higher temperature would lower t volumetric efficiency of the engine.
• C-, and C 10 must be prese in the C 6 -C ⁇ o gasoline and C must be present in the C 6 - gasoline because heavy molecular components have t highest energy density. Since these are the highes density components capable of being gasified and remaini a gas when mixed with air, it is important that they remai in the gasoline for production of engine power.
• the C 6 -C 10 and t C 6 -C 9 gasoline can be adapted for use in engines havi standard carburetion (i.e. - carburetors which do no require gasification in a heated chamber in the absence o air) .
• standard carburetion i.e. - carburetors which do no require gasification in a heated chamber in the absence o air
• primi the C 6 -C 9 and the C 6 -C 10 gasoline with a small amount of volatile component will result in the production of a improved gasoline which may be used in automobiles equippe with standard carburetion.
• the priming agent may be C 4/ C 5 or a mixture of C 4 and C 5 .
• the primed gasoli will have hydrocarbons which consists essentially o hydrocarbons in the range C 4 -C 10 (summer) and C 4 -C (winter)
• the C 4 -C 9 and C 4 -C 10 gasoline is the same as the analogo C 6 -C 9 and C 6 -C 10 gasoline except for the presence of a smal amount of priming agent in both the C-C and C 4 -C gasoline.
• the amount priming agent is an amount effective to raise the front e volatility so that the fuel can be used in cars equipp with standard carburetion.
• the c 4 -c 9 is particular suitable for winter use and the C 4 -C 10 is particular suitable for summer use in cars equipped with standa carburetors. It is particularly significant and surprising that the amount of C 4 or C 5 in the C 4 -C 9 and C 4 -C 10 gasoline is less than the amount of C or C 5 in conventional C 4 -C 12 gasoline without sacrificing any of the desirable properties of the gasoline. It is also surprising that the C 4 -C and C 4 -C ⁇ o gasolines have adequate front end volatility yet are lower in Reid Vapor Pressure than conventional C 4 -C 12 gasoline.
• the gasoline of this invention may also contain any of the various additives presently in use or known to be useful in gasoline.
• this invention produces a gasoline having a low Reid Vapor Pressure, as compared to normal automotive gasoline, it is possible to add large amounts of alcohol such as ethanol to the gasoline of this invention without raising the Reid Vapor Pressure above the current allowable limits.
• Alcohol addition to conventional gasoline is known to raise the Reid Vapor Pressure above the allowable limits.
• Additions of alcohol can be added to the fuels of this invention in an amount of 10-20 per cent by weight without exceeding current Reid Vapor Pressure standards.
• lubricants or anti-knock compounds may be added to the gasoline of this invention.
• a suspension of fine synthetic upper end lubricants or small amounts of anti-knock compounds may be added the gasoline of this invention.
• th fuels of this invention when gasified burn almos completely in the engine producing equivalent torques wit less fuel and at temperatures which are lower than th temperatures achieved when combusting conventional fuels i engines equipped with standard carburetion systems. Thi is true at stoichiometric or slightly higher air-to-fue ratios which would normally result in the development o excessive engine temperature. Therefore, combusting th gasoline of this invention produces less nitrous oxide an allows some increase in compression or superchargin without damage to the engine and without environmenta contaminatio .
• the gasoline of this invention is an intermediat hydrocarbon fuel and naturally exists in the liquid stat at standard temperature and pressure.
• the gasolin can be shipped, stored and dispensed like conventiona gasoline and requires no further processing for use.
• the fuels of thi invention burn cooler than conventional C 4 -C 12 fuel. Fo this reason may be advantageous to add an oxygen source t the fuel to obtain more complete combustion.
• the oxyge source raises the combustion temperature.
• an oxygenate compound may be added to- th fuels of the present invention to raise combustio temperatures or to effect more complete combustion.
• Man suitable oxygen source may be used.
• Typical oxygen source include oxygenated hydrocarbons such as l, 2 butylen oxide.
• Example 1 C 5 -C 10 fuel was made by removing the hydrocarbons lighter than C 5 and the hydrocarbons heavier than C 10 from a conventional C-C-
• the C 4 -C ⁇ 2 gasoline which served as the starting ingredient contains C 5 , C 6 , C 7 , c 8 , Cc,, and c 10 hydrocarbons in addition to the heavy and light hydrocarbons which were removed therefrom.
• the resulting C 5 -C ⁇ o fuel therefore contains C 5 , C 6 C 7 , C 8 , C ⁇ ,, C 10 hydrocarbons.
• the C 5 -C 10 fuel had a Reid Vapor Pressure of 6.
• the fuel was used to start and run a standard carbureted Herbst Herbst engine. Measurements of fuel efficiency were taken and the results are shown in Table I, (line B) . During the test it was noted that the standard carbureted engines started and ran easily even though the fuel had a Reid Vapor Pressure of only 6.
• Example 2 For the purpose of comparison, the C-C 12 fuel described in example 1 was used to start and run a Herbst engine which was identical to the engine used for testing the C 5 -C 0 fuel in example 1.
• the C-C 12 fuel had a Reid Vapor Pressure of 10.
• the efficiency of the C 4 -C 12 fuel was measured and the results are shown in Figure 1 (line A) .
• Example 3 The C 5 -C 10 fuel used in example 1 was also tested in an engine identical to the engine used in example l with the exception that the engine used in example 3 was equipped with an improved carburetion system of the present invention. The fuel efficiency was measured and the results are shown in Table I (line C) . During the test it was noted that the C 5 -C 10 fuel easily started and ran the engine equipped with the improved carburetor even though the fuel had a Reid Vapor Pressure of only 6. While the present invention has been described terms of certain preferred embodiments and exemplified wi respect thereto, one skilled in the art will readi appreciate that variations, modifications, change omissions and substitutions may be made without departi from the spirit thereof. It is intended, therefore, th the present invention be limited solely by the scope of t following claims:

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• Combustion & Propulsion (AREA)
• Organic Chemistry (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)
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• Liquid Carbonaceous Fuels (AREA)
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Citations (6)

• 1990
  • 1990-07-31 DE DE69033497T patent/DE69033497T3/de not_active Expired - Fee Related
  • 1990-07-31 CA CA002088044A patent/CA2088044C/en not_active Expired - Fee Related
  • 1990-07-31 EP EP90916967A patent/EP0541547B2/en not_active Expired - Lifetime
  • 1990-07-31 JP JP51548290A patent/JP3202747B2/ja not_active Expired - Fee Related
  • 1990-07-31 ES ES90916967T patent/ES2146575T5/es not_active Expired - Lifetime
  • 1990-07-31 HU HU9300216A patent/HUT66537A/hu unknown
  • 1990-07-31 BR BR909008035A patent/BR9008035A/pt not_active IP Right Cessation
  • 1990-07-31 WO PCT/US1990/004201 patent/WO1992002600A1/en active IP Right Grant
  • 1990-07-31 AT AT90916967T patent/ATE191233T1/de not_active IP Right Cessation
  • 1990-07-31 AU AU67296/90A patent/AU657467B2/en not_active Ceased

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