Fuel composition

Abstract

There is provided a fuel composition comprising: (a) a gasoline base fuel suitable for use in a spark-ignition internal combustion engine; and (b) a polybutylene polymer; wherein the polybutene polymer has a molecular weight in the range of 200 g / mol to 10,000 g / mol wherein greater than 30% of the polymer molecules in the polybutene polymer have terminal vinylidene groups, and wherein the polybutene polymer is present in a content of 500 ppm to 5000 ppm, based on the weight of the fuel composition. The fuel composition of the present invention provides improved engine power and reduced combustion duration.

Description

Technical Field

[0001] The present invention relates to a liquid fuel composition, particularly a liquid fuel composition that provides increased engine power and has a reduced burn duration in an internal combustion engine. The present invention also relates to a method for increasing the power output of an internal combustion engine, as well as improving efficiency and reducing emissions, by fueling the internal combustion engine with the liquid fuel composition described herein below. The present invention also relates to a method for increasing the burn duration of a liquid fuel composition. Background Art

[0002] In order to improve the engine efficiency, power and acceleration characteristics of modern spark-ignition internal combustion engines, these engines are increasingly being downsized and boosted, as well as having their compression ratios increased.

[0003] In addition to upgrading engine hardware, the fuel formulation used to fuel the engine can also be modified to improve engine efficiency, reduce emissions, and increase power and acceleration in spark-ignition engines. For example, gasoline fuel compositions containing specially formulated refinery components with high octane ratings and good flame speed / burn duration properties can improve power and / or acceleration as well as fuel economy. However, it is desirable to be able to improve power, acceleration, and fuel efficiency performance using standard interchangeable gasoline fuels available on the market.

[0004] So-called highly reactive polybutene polymers have a relatively high proportion (i.e., >30%) of polymer molecules with terminal vinylidene groups. US Pat. No. 6,048,373 discloses a fuel composition comprising a spark-ignition fuel, a Mannich detergent, and a polybutene having a molecular weight distribution of less than 1.4 for controlling intake valve deposits and minimizing valve sticking in spark-ignition internal combustion engines. Preferred polybutenes disclosed therein have a number average molecular weight (Mn) of about 500 to about 2000, and highly reactive polyisobutylene (PIB) is disclosed. Preferred treat rates for polybutenes having a molecular weight distribution of 1.4 or less are said to fall within the range of about 0.5 ptb to about 50 ptb, preferably about 1.5 ptb to about 40 ptb. The highly reactive PIB used in Example 2 had a treat rate of 53.2 ptb, equivalent to about 151 ppm. However, there is no teaching in this document regarding the use of low molecular weight polybutene polymers at selected treat rates to provide increased engine power and reduced burn duration.

[0005] It has now been surprisingly found that the use of low molecular weight polybutenes, such as low molecular weight polyisobutylene (PIB), particularly low molecular weight, highly reactive polyisobutylene (PIB), at selected additive treat rates in gasoline fuel compositions can provide improved power output (increased P maxThe invention provides benefits in terms of improved fuel efficiency and reduced burn duration, even when using standard exchange gasoline fuel. The reduction in burn duration results in more complete combustion in each cycle, which improves engine efficiency and reduces harmful emissions including particulate matter (PM / PN). Summary of the Invention

[0006] According to the present invention, there is provided a fuel composition comprising:

[0007] (a) gasoline base fuel suitable for use in spark-ignition internal combustion engines; and

[0008] (b) polybutene polymers;

[0009] wherein the polybutene polymer has a number average molecular weight in the range of 200 g / mol to 10,000 g / mol, wherein greater than 30% of the polymer molecules in the polybutene polymer have terminal vinylidene groups, and wherein the polybutene polymer is present in an amount of 500 ppm to 5000 ppm by weight of the fuel composition.

[0010] It has surprisingly been found that the fuel compositions of the present invention provide a max The fuel composition of the present invention has the advantages of improved power output and reduced fuel combustion duration. In addition, the fuel composition of the present invention exhibits excellent acceleration, energy efficiency and fuel economy.

[0011] According to another aspect of the present invention, there is provided a method for increasing the power output of an internal combustion engine, the method comprising fueling the internal combustion engine with a liquid fuel composition comprising:

[0012] (a) gasoline base fuel suitable for use in spark-ignition internal combustion engines; and

[0013] (b) polybutene polymers;

[0014] wherein the polybutene polymer has a number average molecular weight in the range of 200 g / mol to 10,000 g / mol, and wherein the polybutene polymer is present in an amount of 500 ppm to 5000 ppm by weight of the fuel composition, preferably wherein the polybutene is a highly reactive polybutene wherein greater than 30% of the polymer molecules in the polybutene polymer have terminal vinylidene groups.

[0015] According to another aspect of the present invention, there is provided a method for increasing the P of an internal combustion engine. max A method comprising fueling an internal combustion engine with a liquid fuel composition comprising:

[0016] (a) gasoline base fuel suitable for use in spark-ignition internal combustion engines; and

[0017] (b) polybutene polymers;

[0018] wherein the polybutene polymer has a number average molecular weight in the range of 200 g / mol to 10,000 g / mol, and wherein the polybutene polymer is present in an amount of 500 ppm to 5000 ppm by weight of the fuel composition, preferably wherein the polybutene is a highly reactive polybutene wherein greater than 30% of the polymer molecules in the polybutene polymer have terminal vinylidene groups.

[0019] According to yet another aspect of the present invention, there is provided a method of reducing the burn duration of a liquid fuel composition in an internal combustion engine, wherein the method comprises blending a polybutene polymer with a gasoline base fuel to produce a gasoline fuel composition, wherein the polybutene polymer is blended with the gasoline base fuel in an amount of 500 ppm to 5000 ppm by weight of the gasoline fuel composition, and wherein the polybutene has a molecular weight in the range of 200 g / mol to 10,000 g / mol, and combusting the fuel composition in a spark-ignited internal combustion, preferably wherein the polybutene is a highly reactive polybutene wherein greater than 30% of the polymer molecules in the polybutene polymer have terminal vinylidene groups.

[0020] According to yet another aspect of the present invention, there is provided a use of a liquid fuel composition for increasing the power output of an internal combustion engine, wherein the liquid fuel composition comprises:

[0021] (a) gasoline base fuel suitable for use in spark-ignition internal combustion engines; and

[0022] (b) polybutene polymers;

[0023] wherein the polybutene polymer has a number average molecular weight in the range of 200 g / mol to 10,000 g / mol, and wherein the polybutene polymer is present in an amount of 500 ppm to 5000 ppm by weight of the fuel composition, preferably wherein the polybutene is a highly reactive polybutene wherein greater than 30% of the polymer molecules in the polybutene polymer have terminal vinylidene groups.

[0024] According to another aspect of the present invention, there is provided a liquid fuel composition for improving the P of an internal combustion engine. max The use of a liquid fuel composition, wherein the liquid fuel composition comprises:

[0025] (a) gasoline base fuel suitable for use in spark-ignition internal combustion engines; and

[0026] (b) polybutene polymers;

[0027] wherein the polybutene polymer has a number average molecular weight in the range of 200 g / mol to 10,000 g / mol, and wherein the polybutene polymer is present in an amount of 500 ppm to 5000 ppm by weight of the fuel composition, preferably wherein the polybutene is a highly reactive polybutene wherein greater than 30% of the polymer molecules in the polybutene polymer have terminal vinylidene groups.

[0028] According to yet another aspect of the present invention, there is provided a use of a polybutene polymer in a liquid fuel composition for reducing burn duration, wherein the liquid fuel composition comprises:

[0029] (a) gasoline base fuel suitable for use in spark-ignition internal combustion engines; and

[0030] (b) polybutene polymers;

[0031] wherein the polybutene polymer has a number average molecular weight in the range of 200 to 10,000, and wherein the polybutene polymer is present in an amount of 500 ppm to 5000 ppm by weight of the fuel composition, preferably wherein the polybutene is a highly reactive polybutene wherein greater than 30% of the polymer molecules in the polybutene polymer have terminal vinylidene groups. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is the average P measured at the engine conditions of 1300 rpm and 11.5 bar shown in Table 3 max Graphical representation of data.

[0033] Figure 2 is the average P measured at the engine conditions of 3300 rpm and 12.4 bar shown in Table 3 max Graphical representation of data.

[0034] Figure 3 is P in Table 5 max A graphical representation of the data and showing the average P values ​​generated by burning the base fuel and the test fuels (Examples 2-7) at 1300 rpm and 11.5 bar (IGN 2 degrees BTDC) per day. max .

[0035] Figure 4 is P in Table 5 max A graphical representation of the data and showing the P max The average % difference in % compared to the base fuel run on that day for each of Examples 2-7 (where the base fuel results in Table 5 are normalized to zero).

[0036] Figure 5is a graphical representation of the burn duration data in Table 5 and shows the average % difference in burn duration versus the base fuel control for that day's run for each of Examples 7-11 (where the base fuel results in Table 5 are normalized to zero).

[0037] Figure 6 is the average P measured at the engine conditions of 1300 rpm and 11.5 bar shown in Table 7 max Graphical representation of data.

[0038] Figure 7 is a graphical representation of the average combustion duration shown in Table 7 (at 1300 rpm and 11.5 bar). DETAILED DESCRIPTION

[0039] As used herein, the term "power output" refers to the amount of drag power required to maintain a fixed speed under wide-open throttle conditions in a chassis dynamometer test.

[0040] As used herein, the term " max ” refers to a direct measurement of the force generated by the decomposition of fuel.

[0041] According to the present invention, there is provided a method of increasing the power output of an internal combustion engine. Furthermore, according to the present invention, there is a method of increasing the power output of an internal combustion engine. max In the context of these aspects of the invention, the term "increase" encompasses any degree of increase. According to the present invention, the increase can be, for example, the power output or P provided by a fuel formulation prior to the addition of the low molecular weight, preferably highly reactive polybutene to a similar fuel formulation. max According to the present invention, the power output or P max The increase in power output or P can even be as high as that provided by the fuel formulation before the addition of the low molecular weight, preferably highly reactive polybutene to a similar fuel formulation. max 10% of.

[0042] Low molecular weight, preferably highly reactive polybutenes can also be used to increase the acceleration of an internal combustion engine. As used herein, the term "acceleration" refers to the amount of time required for an engine to increase speed between two fixed speed conditions in a given gear. In the context of this aspect of the invention, the term "increase" encompasses any degree of increase and is used when power and or P are increased. max When increased to the above level, the same percentage can be increased.

[0043] According to the present invention, the power output and acceleration provided by the fuel composition can be determined in any manner known to those skilled in the art (e.g., as taught in SAE Paper 2005-01-0239 and SAE Paper 2005-01-0244).

[0044] As used herein, the term "combustion duration" refers to the time (in engine crank angle degrees) required for combustion to progress from 10% to 90% (referred to as AI 10-90 in the following examples). The term AI 50-90 is also used in connection with combustion duration and refers to the time (in engine crank angle degrees) required for combustion to progress from 50% to 90%. Combustion studies can be performed by monitoring in-cylinder pressure data. Piezoelectric pressure sensors can be used to collect pressure data, from which the mass fraction burn (MFB) or burn duration can be calculated. More information on how MFB can be calculated can be found in SAE paper 2014-01-1336, "Mass Fraction Burn Investigation of Lean Burn Low BTU Gasification Gas in Direct-injection Spark-ignition Engines," published on April 1, 2014 by Ftwi Yohaness Hagos and Abd Rashid Abd Aziz.

[0045] According to the present invention, there is provided a method of reducing the burn duration of a gasoline fuel composition, wherein the method comprises adding a polybutene polymer to the gasoline fuel composition, wherein the polybutene polymer is added in an amount of 500 ppm to 5000 ppm by weight of the gasoline fuel composition, and wherein the polybutene has a number average molecular weight in the range of 200 g / mol to 10,000 g / mol.

[0046] According to the present invention, the burning duration of a fuel composition may be determined in any known manner, for example using the test method disclosed in the Examples section below.

[0047] In the context of this aspect of the invention, the term "reduction in burn duration" encompasses any degree of reduction. According to the present invention, the reduction may be, for example, a reduction of 0.05% or more, preferably 0.1% or more, more preferably 0.2% or more, even more preferably 0.5% or more, especially 1% or more, more especially 2% or more, and even more especially 4% or more, or 5% or more of the burn duration provided by the fuel formulation before the addition of the low molecular weight, preferably highly reactive polybutene to a similar fuel formulation. According to the present invention, the reduction in burn duration may even be as much as a 10% reduction in the burn duration provided by the fuel formulation before the addition of the low molecular weight, preferably highly reactive polybutene to a similar fuel formulation.

[0048] The term "flame speed" or "laminar flame speed" (LFS) refers to laminar burning velocity. LFS is a basic measure of flame propagation rate without the complexities of mixing dynamics. However, in engines, mixing dynamics play a role, so the flame speed measured is called "burning rate" and "burning duration". The terms "burning rate" and "burning duration" are also used interchangeably with "flame speed" in this article. Laminar burning velocity (LBV) is a fundamental property of a chemical composition. It is defined as the rate at which unburned gases propagate to the flame front and react to form products (perpendicular to the flame front under laminar flow conditions).

[0049] The flame speed of a fuel composition can be determined in any known manner, for example, the LFS can be measured using any of the following three methods:

[0050] 1. Stagnant flame method (up to 5atm-7atm)

[0051] 2. Spherical expansion method, constant pressure or constant volume (up to 60atm-80atm)

[0052] 3. Heat flux method (up to about 5atm).

[0053] All three methods are described in review publications: Egolfopoulos, FN, Hansen, N., Ju, Y., K., Law, CK and Qi, F. "Advances and challenges in laminar flame experiments and implications for combustion chemistry", Progress in Energy and Combustion Science 43(2014) 36-67, https: / / doi.org / 10.1016 / j.pecs.2014.04.004.

[0054] The following method for measuring flame speed in a constant volume combustion chamber (spherical bomb) is based on Gillespie, LL, M., Sheppard, CG, Wooley, R, Aspects of laminar and turbulent burning velocity relevant to spark ignition engines, Journal of the Society of Automotive Engineers, 2000 (2000-01-0192).

[0055] The following method for measuring flame speed uses the net pressure method: Mittal, M., Zhu, G., and Schock H., 'Fast mass-fraction-burned calculation using the net pressure method for real-time applications', Proc. Instn Mech Engrs, Part D: J. Automobile Engineering 223(3) (2009): 389-394.

[0056] The liquid fuel composition of the present invention comprises a base fuel suitable for use in internal combustion engines and a low molecular weight, preferably highly reactive polybutene. Typically, the base fuel suitable for use in internal combustion engines is gasoline or diesel fuel, and therefore the liquid fuel composition of the present invention is typically a gasoline composition or a diesel fuel composition. Preferably, the base fuel is a gasoline base fuel.

[0057] The polybutene used herein is preferably a highly reactive polybutene. A highly reactive polybutene is a polybutene having a relatively high proportion (i.e., greater than 30%) of polymer molecules having terminal vinylidene groups. As used herein, the term "polybutene" includes polymers made from pure or substantially pure 1-butene or isobutylene and polymers made from mixtures of two or all three of 1-butene, 2-butene, and isobutylene, as well as polymers containing small amounts, preferably less than 10% by weight, more preferably less than 5% by weight, of C2, C3, C5, and higher olefins and dienes. In a preferred embodiment, the polybutene is a polyisobutylene (also referred to as "polyisobutylene"), preferably wherein at least 90% by weight, more preferably at least 95% by weight, of the polymer is derived from isobutylene.

[0058] In a particularly preferred embodiment, the polybutene is a highly reactive polyisobutylene.

[0059] In one embodiment, the highly reactive polybutene has greater than 40% of the polymer molecules having terminal vinylidene groups.

[0060] In another embodiment, the highly reactive polybutene polymer has greater than 50% of the polymer molecules having terminal vinylidene groups.

[0061] In a preferred embodiment, the highly reactive polybutene polymer has greater than 70% of the polymer molecules having terminal vinylidene groups.

[0062] In another preferred embodiment, the highly reactive polybutene has more than 85% of its double bonds located in the terminal position of the molecule.

[0063] The highly reactive polybutene polymer for use herein preferably has a molecular weight distribution of 1.5 or greater, preferably 1.6 or greater, more preferably 1.7 or greater, even more preferably 1.8 or greater.

[0064] The polybutene polymer is present in an amount of 500 ppm to 5000 ppm, preferably 1000 ppm to 5000 ppm, more preferably 2500 ppm to 5000 ppm, based on the weight of the fuel composition. Examples of preferred amounts of polybutene include 2500 ppm and 5000 ppm, based on the weight of the fuel composition.

[0065] One or more polybutene polymers may be used in the fuel compositions herein. When more than one polybutene polymer is used herein, the total amount of polybutene polymers is in the same range as given in the previous paragraph.

[0066] The polybutene polymer used herein is a low molecular weight polybutene polymer. As used herein, the term "low molecular weight polybutene" means a polymer having a number average molecular weight (M) in the range of 200 g / mol to 10,000 g / mol, preferably 500 g / mol to 5000 g / mol, more preferably 1000 g / mol to 5000 g / mol. n In one embodiment of the present invention, the polybutene used herein, preferably the highly reactive polybutene, has a number average molecular weight (M) of 1000 g.mol to 2300 g.mol. n In another embodiment of the present invention, the polybutene used herein has a number average molecular weight (M) of 2300 g / mol to 5000 g / mol. n ). The number average molecular weight of the polybutene polymer can be determined using gel permeation chromatography.

[0067] The highly reactive polybutene for use herein may be bio-derived or non-bio-derived.In one embodiment of the present invention, the polybutene is a low molecular weight, highly reactive polyisobutylene derived from 100% renewable feedstock.

[0068] The highly reactive polybutene for use herein preferably contains less than 1 mg / kg of chlorine.

[0069] In one embodiment, the highly reactive polybutene polymers used herein have a molecular weight of 190 mm at 100°C. 2 / s or greater, preferably at 190mm 2 / s to 1500mm 2 / s, more preferably within the range of 430mm 2 / s to 1500mm 2 The kinematic viscosity is in the range of / s.

[0070] Preferred high reactive polybutenes for use herein have an alpha olefin content greater than 85%.

[0071] Suitable highly reactive polybutenes for use herein include those commercially available from BASF under the tradename Glissopal (RTM), such as Glissopal (RTM) 1000, Glissopal (RTM) 1300, and Glissopal (RTM) 2300.

[0072] Glissopal (RTM) 1000 has a number average molecular weight (M) of 1000 g / mol. n ), molecular weight distribution of 1.6 (M w / M n), more than 85% alpha olefin content, 190mm at 100 ° C 2 / s kinematic viscosity and less than 1mg / kg chlorine content.

[0073] Glissopal (RTM) 1300 has a number average molecular weight (M) of 1300 g / mol. n ), molecular weight distribution of 1.7 (M w / M n ), more than 85% alpha olefin content, 190mm at 100 ° C 2 / s kinematic viscosity and less than 1mg / kg chlorine content.

[0074] Glissopal (RTM) 2300 has a number average molecular weight (M n ), molecular weight distribution of 1.6 (M w / M n ), more than 85% alpha olefin content, 190mm at 100 ° C 2 / s kinematic viscosity and less than 1mg / kg chlorine content.

[0075] Also suitable for use herein are Glissopal (RTM) 1000 BMBcert, 1300 BMBcert, and 2300 BMBcert(TM), which are low molecular weight, highly reactive polyisobutylenes derived from 100% renewable raw materials commercially available from BASF.

[0076] The polybutene polymer can be blended with any other additives (eg, an additive performance package) to prepare an additive blend. The additive blend is then added to a base fuel to prepare a liquid fuel composition.

[0077] The amount of the performance package in the additive blend is preferably in the range of 0.1 wt% to 99.8 wt%, more preferably in the range of 5 wt% to 50 wt%, based on the weight of the additive blend.

[0078] Preferably, the amount of the performance package present in the liquid fuel composition of the present invention is in the range of 15 ppmw (parts per million by weight) to 10 wt.%, based on the total weight of the liquid fuel composition. More preferably, the amount of the performance package present in the liquid fuel composition of the present invention further complies with one or more of the parameters (i) to (xv) listed below:

[0079] (i) At least 100 ppmw

[0080] (ii) at least 200 ppmw

[0081] (iii) at least 300 ppmw

[0082] (iv) At least 400 ppmw

[0083] (v) At least 500 ppmw

[0084] (vi) At least 600 ppmw

[0085] (vii) At least 700 ppmw

[0086] (viii) At least 800 ppmw

[0087] (ix) At least 900 ppmw

[0088] (x) At least 1000 ppmw

[0089] (xi) At least 2500 ppmw

[0090] (xii) Up to 5000 ppmw

[0091] (xiii) Up to 10,000 ppmw

[0092] (xiv) up to 2 wt%.

[0093] (xv) up to 5 wt%.

[0094] In liquid fuel composition of the present invention, if used base fuel is gasoline, then gasoline can be any gasoline that is applicable to spark ignition (petroleum) type internal combustion engine known in the art, comprises automobile engine and other types of engines, for example off-road and aircraft engine.The gasoline used as base fuel in liquid fuel composition of the present invention also can be called ' base gasoline ' conveniently.This gasoline also can comprise the biocomponent of various content and with the biological stream of any content, maintains suitable analytical specification simultaneously.Biological component can be from any biomass conversion process, comprises various uncatalyzed and catalytic biomass pyrolysis, hydrothermal liquefaction, non-thermal biomass conversion, such as the biochemical process of microbial catalysis etc.Any biomass that is suitable as the raw material of these processes all is ideal.

[0095] Gasoline generally comprises a mixture of hydrocarbons having a boiling point in the range of 25°C to 230°C (EN-ISO 3405), the optimum range and the distillation curve generally varying with the climate and the season of the year. The hydrocarbons in gasoline may be obtained by any means known in the art, conveniently the hydrocarbons may be obtained in any known manner from straight-run gasoline, synthetically produced aromatic hydrocarbon mixtures, thermally or catalytically cracked hydrocarbons, hydrocracked petroleum fractions, catalytically reformed hydrocarbons or mixtures of these.

[0096] The specific distillation curve, hydrocarbon composition, research octane number (RON) and motor octane number (MON) of the gasoline are not critical.

[0097] Conveniently, the gasoline may have a Research Octane Number (RON) of at least 80, for example in the range of 80 to 110, preferably the gasoline will have a RON of at least 90, for example in the range of 90 to 110, more preferably the gasoline will have a RON of at least 91, for example in the range of 91 to 105, even more preferably the gasoline will have a RON of at least 92, for example in the range of 92 to 103, even more preferably the gasoline will have a RON of at least 93, for example in the range of 93 to 102, and most preferably the gasoline will have a RON of at least 94, for example in the range of 94 to 100 (EN 25164); the gasoline may conveniently have a Motor Octane Number (MON) of at least 70, for example in the range of 70 to 110, preferably the gasoline will have a MON of at least 75, for example in the range of 75 to 105, more preferably the gasoline will have a MON of at least 80, for example in the range of 80 to 100, most preferably the gasoline will have a MON of at least 82, for example in the range of 82 to 95 (EN 25164). 25163).

[0098] Typically, gasoline comprises components selected from one or more of the following groups: saturated hydrocarbons, olefins, aromatic hydrocarbons and oxygenated hydrocarbons. Conveniently, gasoline may comprise a mixture of saturated hydrocarbons, olefins, aromatic hydrocarbons and optionally oxygenated hydrocarbons.

[0099] Typically, the olefin content of gasoline is in the range of 0% to 40% by volume based on gasoline (ASTM D1319); preferably, the olefin content of gasoline is in the range of 0% to 30% by volume based on gasoline, and more preferably, the olefin content of gasoline is in the range of 0% to 20% by volume based on gasoline.

[0100] Typically, the aromatic content of gasoline is in the range of 0% to 70% by volume based on gasoline (ASTM D1319), for example, the aromatic content of gasoline is in the range of 10% to 60% by volume based on gasoline; preferably, the aromatic content of gasoline is in the range of 0% to 50% by volume based on gasoline, for example, the aromatic content of gasoline is in the range of 10% to 50% by volume based on gasoline.

[0101] In one embodiment herein, the gasoline base fuel comprises less than 10% by volume of aromatic compounds based on the total base fuel. In another embodiment herein, the gasoline base fuel comprises less than 2% by volume of aromatic compounds having 9 or more carbon atoms based on the total base fuel.

[0102] The benzene content of gasoline is at most 10% by volume, more preferably at most 5% by volume, in particular at most 1% by volume, based on the gasoline.

[0103] The gasoline preferably has a low or ultra-low sulfur content, for example at most 1000 ppmw (parts per million by weight), preferably not more than 500 ppmw, more preferably not more than 100 ppmw, even more preferably not more than 50 ppmw and most preferably not more than even 10 ppmw.

[0104] The gasoline also preferably has a low total lead content, such as at most 0.005 g / l, and is most preferably unleaded, having no lead compounds added thereto (ie, unleaded).

[0105] When the gasoline contains oxygenated hydrocarbons, at least a portion of the non-oxygenated hydrocarbons will replace the oxygenated hydrocarbons (match blending) or simply be added to the fully formulated gasoline (splash blending). The oxygenate content of the gasoline may be up to 85% by weight (EN 1601) (e.g., ethanol alone), based on the gasoline. For example, the oxygenate content of the gasoline may be up to 35% by weight, preferably up to 25% by weight, more preferably up to 10% by weight. Conveniently, the oxygenate concentration will have a minimum concentration selected from any one of 0%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, and 1.2%, and a maximum concentration selected from any one of 12%, 8%, 7.2%, 5%, 4.5%, 4.0%, 3.5%, 3.0%, and 2.7% by weight.

[0106] Examples of oxygenated hydrocarbons that can be blended into gasoline include alcohols, ethers, esters, ketones, aldehydes, carboxylic acids and their derivatives, and oxygen-containing heterocyclic compounds. Preferably, the oxygenated hydrocarbons that can be blended into gasoline are selected from alcohols (such as methanol, ethanol, propanol, 2-propanol, butanol, tert-butanol, isobutanol, and 2-butanol), ethers (preferably ethers containing 5 or more carbon atoms per molecule, such as methyl tert-butyl ether and ethyl tert-butyl ether), and esters (preferably esters containing 5 or more carbon atoms per molecule); a particularly preferred oxygenated hydrocarbon is ethanol.

[0107] When oxygenated hydrocarbons are present in the gasoline, the amount of oxygenated hydrocarbons in the gasoline can vary over a wide range. For example, gasolines containing a relatively large proportion of oxygenated hydrocarbons are currently commercially available in countries such as Brazil and the United States, such as ethanol itself and E85, as well as gasolines containing a smaller proportion of oxygenated hydrocarbons, such as E10 and E5. Thus, gasoline can contain up to 100% by volume of oxygenated hydrocarbons. Also included herein is E100 fuel, as used in Brazil. Preferably, the amount of oxygenated hydrocarbons present in the gasoline is selected from one of the following amounts: up to 85% by volume; up to 70% by volume; up to 65% by volume; up to 30% by volume; up to 20% by volume; up to 15% by volume; and up to 10% by volume, depending on the desired final formulation of the gasoline. Conveniently, the gasoline can contain at least 0.5%, 1.0%, or 2.0% by volume of oxygenated hydrocarbons.

[0108] Examples of suitable gasolines include gasolines having an olefin content of 0 to 20 vol% (ASTM D1319), an oxygen content of 0 to 5 wt% (EN 1601), an aromatics content of 0 to 50 vol% (ASTM D1319), and a benzene content of up to 1 vol%.

[0109] Also suitable for use herein are gasoline blending components that may be derived from sources other than crude oil, such as low-carbon gasoline fuels from biomass or CO2, and their blends with each other or with gasoline streams and components of fossil origin. Suitable examples of such fuels include:

[0110] 1) Biomass sources:

[0111] a. straight-run bio-naphtha from hydrodeoxygenated biomass, and

[0112] b. cracking and / or isomerization products of synthetic wax (biomass gasification to synthesis gas

[0113] (CO / H2), synthetic wax obtained by the Fischer-Tropsch (FT) process), which is then hydrocracked / hydroisomerized to produce a range of products including fractions in the gasoline range.

[0114] 2) Source of CO2:

[0115] a. CO2+H2 synthesis gas (CO / H2) (derived from synthetic wax via a modified water / gas shift reaction followed by the FT process) which is then hydrocracked / hydroisomerized to produce a range of products including fractions within the gasoline range.

[0116] 3) Methanol source:

[0117] a. Biomass gasification to synthesis gas (CO / H2), then to methanol, and then to gasoline through the MTG process (MTG is the 'methanol-gasoline' process). To further reduce the carbon intensity of the fuel, the H2 used in all processes will be renewable from water electrolysis using renewable electricity (such as from wind and solar).

[0118] (Green)H2.

[0119] Particularly suitable for use herein are gasoline blending components that may be derived from biological sources. Examples of such gasoline blending components may be found in WO2009 / 077606, WO2010 / 028206, WO2010 / 000761, European Patent Application Nos. 09160983.4, 09176879.6, 09180904.6, and US Patent Application Serial No. 61 / 312307.

[0120] Although not critical to the present invention, except low molecular weight, preferably highly reactive polybutene, the base gasoline or gasoline composition of the present application can conveniently include one or more optional fuel additives. The concentration and property of the optional fuel additives that may be included in the base gasoline or gasoline composition of the present invention are not critical. Non-limiting examples of suitable types of fuel additives that may be included in the base gasoline or gasoline composition of the present invention include antioxidants, corrosion inhibitors, detergents, demisters, antiknock additives, metal deactivators, valve seat recession protectant compounds, dyes, solvents, carrier fluids, diluents, and markers. Examples of suitable such additives are generally described in U.S. Patent number 5,855,629.

[0121] Conveniently, the fuel additive may be blended with one or more solvents to form an additive concentrate, and the additive concentrate may then be mixed with the base gasoline or gasoline composition of the present invention.

[0122] The (active matter) concentration of any optional additives present in the base gasoline or gasoline composition of the present invention is preferably up to 1% by weight, more preferably in the range of 5 ppmw to 2000 ppmw, advantageously in the range of 300 ppmw to 1500 ppmw, such as 300 ppmw to 1000 ppmw.

[0123] Other conventional additives used in gasoline are corrosion inhibitors, for example based on ammonium salts of organic carboxylic acids, which tend to form films, or based on ammonium salts of heterocyclic aromatic hydrocarbons for corrosion protection of non-ferrous metals; dehazers; antiknock additives; metal deactivators; solvents; carrier fluids; diluents; antioxidants or stabilizers, for example based on amines such as phenylenediamines, for example p-phenylenediamine, N,N'-di-sec-butyl-p-phenylenediamine, dicyclohexylamine or derivatives thereof, or based on phenols such as 2,4-di-tert-butylphenol or 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid; antistatic agents; metallocenes such as ferrocene; methyl-cyclopentadienyl manganese tricarbonyl; lubricating additives such as certain fatty acids, alkenyl succinates, bis(hydroxyalkyl) fatty amines, hydroxyacetamides or castor oil; and dyes (markers). Suitable additives of this type are disclosed in U.S. Pat. No. 5,855,629. If appropriate, amines may also be added, for example as described in WO 03 / 076554. Optionally, an anti-seat recession additive may be used, such as a sodium or potassium salt of a polymeric organic acid.

[0124] The gasoline compositions herein may also comprise a detergent additive. Suitable detergent additives include those disclosed in WO2009 / 50287, which is incorporated herein by reference.

[0125] Preferred detergent additives for use in the gasoline compositions herein generally have at least one hydrophobic hydrocarbon group having a number average molecular weight (Mn) of from 85 to 20,000 and at least one polar moiety selected from the group consisting of:

[0126] (A1) a monoamino or polyamino group having up to 6 nitrogen atoms, at least one of which is basic;

[0127] (A6) polyoxy-C2- to -C4-alkylene groups, which are terminated by hydroxyl, monoamino or polyamino groups, in which at least one nitrogen atom is basic, or by carbamate groups;

[0128] (A8) a moiety derived from succinic anhydride and having a hydroxyl group and / or an amino group and / or an amide group and / or an imide group; and / or

[0129] (A9) Moieties obtained by Mannich reaction of substituted phenols with aldehydes and mono- or polyamines.

[0130] The hydrophobic hydrocarbon group in the above-mentioned detergent additive that ensures sufficient solubility in the base fluid has a number average molecular weight (Mn) of 85 to 20,000, especially 113 to 10,000, and particularly 300 to 5000. Typical hydrophobic hydrocarbon groups, especially those combined with polar moieties (A1), (A8) and (A9), include polyalkene (polyolefin), such as polypropylene, polybutene and polyisobutene, each of which has an Mn of 300 to 5000, preferably 500 to 2500, more preferably 700 to 2300, and particularly 700 to 1000.

[0131] Non-limiting examples of the above detergent additive package include the following:

[0132] The additive containing monoamino or polyamino groups (A1) is preferably a polyolefin monoamine or polyolefin polyamine based on polypropylene with an Mn of 300 to 5000 or conventional (i.e., predominantly internal double bonds) polybutene or polyisobutene. When polybutene or polyisobutene predominantly having internal double bonds (usually in the β and γ positions) is used as the starting material for preparing the additive, possible preparation routes are by chlorination and subsequent amination, or by oxidation of the double bonds with air or ozone to give carbonyl or carboxyl compounds and subsequent amination under reducing (hydrogenation) conditions. The amine used for the amination here can be, for example, ammonia, a monoamine or a polyamine, such as dimethylaminopropylamine, ethylenediamine, diethylenetriamine, triethylenetetramine or tetraethylenepentamine. Corresponding additives based on polypropylene are described in particular in WO-A-94 / 24231.

[0133] Further preferred additives comprising monoamino groups (A1) are the hydrogenation products of reaction products of polyisobutene having an average degree of polymerization of 5 to 100 with nitrogen oxides or mixtures of nitrogen oxides and oxygen, as described in particular in WO-A-97 / 03946.

[0134] Further preferred additives comprising monoamino groups (A1) are compounds obtainable from polyisobutene epoxides by reaction with amines and subsequent dehydration and reduction of amino alcohols, as described in particular in DE-A-19620 262.

[0135] The additive comprising a polyoxy-C2-C4-alkylene moiety (A6) is preferably a polyether or a polyetheramine, which can be obtained by a C2- to C4-alkylene moiety. 60 -alkanols, C6- to C 30 -alkanediol, mono- or di-C2-C 30 -alkylamine, C1-C 30 -alkylcyclohexanol or C1-C 30 Alkylphenols are obtained by reacting 1 to 30 mol of ethylene oxide and / or propylene oxide and / or butylene oxide per hydroxyl or amino group, and in the case of polyetheramines, by subsequent reductive amination with ammonia, monoamines or polyamines. Such products are described in particular in EP-A-310 875, EP-A-356 725, EP-A-700 985 and US-A-4 877 416. In the case of polyethers, such products also have the properties of carrier oils. Typical examples of these products are tridecanol butoxylates, isotridecanol butoxylates, isononylphenol butoxylates and polyisobutenol butoxylates and propoxylates, as well as the corresponding reaction products with ammonia.

[0136] The additive comprising moieties (A8) derived from succinic anhydride and having hydroxyl and / or amino and / or amide and / or imide groups is preferably the corresponding derivative of polyisobutenylsuccinic anhydride, which can be obtained by reacting conventional or highly reactive polyisobutenes having an Mn of 300 to 5000 with maleic anhydride by a thermal route or via chlorination of polyisobutene. Of particular interest are derivatives with aliphatic polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine or tetraethylenepentamine. Such additives are described in particular in US Pat. No. 4,849,572.

[0137] The additive comprising a moiety (A9) obtained by the Mannich reaction of a substituted phenol with an aldehyde and a mono- or polyamine is preferably a reaction product of a polyisobutene-substituted phenol with formaldehyde and a mono- or polyamine such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine or dimethylaminopropylamine. The polyisobutenyl-substituted phenol can be derived from conventional or highly reactive polyisobutenes having an Mn of 300 to 5000. Such "polyisobutene-Mannich bases" are described in particular in EP-A-831 141.

[0138] Preferably, the detergent additive used in the gasoline composition of the present invention comprises at least one nitrogen-containing detergent, more preferably at least one nitrogen-containing detergent comprising a hydrophobic hydrocarbon group having a number average molecular weight in the range of 300 to 5000. Preferably, the nitrogen-containing detergent is selected from the group consisting of polyolefin monoamines, polyetheramines, polyolefin Mannich amines, and polyolefin succinimides. Conveniently, the nitrogen-containing detergent may be a polyolefin monoamine.

[0139] In the above, the amounts (concentrations, volume %, ppmw, weight %) of the components are the amounts of active matter, ie excluding volatile solvent / diluent materials.

[0140] The liquid fuel composition of the present invention can be produced by blending a substantially low molecular weight, preferably highly active, polybutene polymer with a gasoline base fuel suitable for use in internal combustion engines. Since the base fuel into which the primary fuel additive is blended is gasoline, the liquid fuel composition produced is a gasoline composition.

[0141] It has surprisingly been found that the combined use of low molecular weight, preferably highly reactive polybutenes having a number average molecular weight of 500 to 10,000 g / mol and present in an amount of 500 to 5000 ppm by weight of the fuel composition has the effect of increasing the power and increasing the P of an internal combustion engine fueled by a liquid fuel composition containing the polybutene relative to an internal combustion engine fueled by a liquid base fuel. max In preferred embodiments herein, power improvements are observed under low load and low speed conditions (such as 1300 rpm and 11.5 bar) and under high load and high speed conditions (such as 3300 rpm and 12.4 bar). Highly reactive polyisobutylene polymers having a molecular weight of 2300 or greater have been found to be particularly beneficial in increasing power output under low speed / low load conditions.

[0142] It has also been surprisingly found that the combined use of a low molecular weight, preferably highly reactive polybutene having a number average molecular weight of from 500 g / mol to 10,000 g / mol and present in an amount of from 500 ppm to 5000 ppm by weight of the fuel composition provides a benefit in terms of reducing the combustion duration of a liquid fuel composition containing said polybutene relative to an internal combustion engine fueled by a liquid base fuel.

[0143] The present invention will be further understood by reference to the following examples. Unless otherwise indicated, all amounts and concentrations disclosed in the examples are based on the weight of the fully formulated fuel composition.

[0144] Example

[0145] Example 1

[0146] A set of experiments was performed to test the combustion enhancement properties of highly reactive polyisobutylene (PIB) using a gasoline single cylinder engine (GSCE). The base fuel was a RON 96E10 base gasoline fuel containing 28% aromatics in accordance with the North American premium specification ASTM D4814, which contained no performance additives. A polyisobutylene having a number average molecular weight (M) of 1000 g / mol was added. n A highly reactive polyisobutylene (PIB) of 1,2-diol-1,4-diol-2-ol, commercially available from BASF under the trade name Glissopal (RTM) 1000, was added to the base fuel at a treat rate of 5000 ppm.

[0147] Test conditions

[0148] The engine used for these experiments was a gasoline single-cylinder engine. The engine was manufactured by AVL and was based on the EA888 2.0L Audi TFSI / VW TSI (Euro 6). The single-cylinder bench engine details are shown in Table 1 below.

[0149] Table 1

[0150]

[0151]

[0152] The engine test conditions are detailed in Table 2 below.

[0153] Table 2

[0154] Engine test Speed ​​[RPM] IMEP[Brazil] Inlet pressure Intake air temperature Exhaust back pressure Fuel pressure Fuel temperature Test conditions [mbara] [℃] [mbara] [bar] [℃] 1300HL 1300 11.5 1110 35 1080 3 25 1300ML 1300 8 905 35 1080 3 25 3300HL 3300 12.4 1205 35 1850 3 25

[0155] The following test regimen was conducted daily using the base fuel and one test fuel:

[0156] Preheat the engine and discharge the base fuel linearly

[0157] Run baseline spark scans: 1300ML, HL, 3000ML (ML = medium load;

[0158] HL = High Load)

[0159] ● Switch to test fuel and flush 30 liters

[0160] ● Test: Spark scanning was performed under three different conditions (1300 rpm, IMEP: 11.5 bar and 8 bar; and 3300 rpm, IMEP: 12.4 bar)

[0161] ●End.

[0162] Each test fuel blend was screened twice, once in each of two random loops.

[0163] In Table 3 below and Figure 1 and Figure 2 The average maximum pressure (P) generated by burning the base fuel and the test fuel (Example 1) is shown in FIG. max ).

[0164] Table 3

[0165]

[0166]

[0167] Figure 1 The average P values ​​produced by burning the base fuel and the test fuel (Example 1) at 1300 rpm and 11.5 bar are shown. max .

[0168] Figure 2 The average P values ​​produced by burning the base fuel and the test fuel (Example 1) at 3300 rpm and 12.4 bar are shown. max .

[0169] Examples 2 to 7

[0170] Another set of experiments was conducted on several additional test fuel blends using the same base fuel and using the same test conditions and test protocol as in Example 1 above. The test fuel blends of Examples 2 to 7, each containing a highly reactive PIB, are shown in Table 4 below. The molecular weight of the highly reactive PIB used in each fuel is shown in parentheses in column 2 of Table 4. Two different HR-PIBs were used, one having a number average molecular weight of 1000 g / mol, commercially available from BASF under the trade name Glissopal (RTM) 1000, and the other having a number average molecular weight of 2300 g / mol, commercially available from BASF under the trade name Glissopal (RTM) 2300. The treat rate, RON, MON, and RON-MON for each of the test blends are also shown in Table 4.

[0171] Table 4

[0172] Example PIB(MW) PIB dose, ppmw RON MON RON-MON 2 PIB(1000) 5000 96.5 86 10.5 3 PIB(1000) 2500 96.4 86.1 10.3 4 PIB(1000) 1000 96.4 86.2 10.2 5 PIB(2300) 2500 96.4 85.8 10.6 6 PIB(2300) 5000 96.2 85.9 10.3 7 PIB(2300) 1000 96.3 85.8 10.5

[0173] P was measured for each of Examples 2 to 7 and the base fuel. max and combustion duration, and the results are listed in Table 5 below. Table 5 also lists the P values ​​for each test blend run that day compared to the base fuel control. maxand the difference in burning duration in %.

[0174] P max The start of combustion is ignition, and the end of combustion is the point of maximum pressure P max Burn duration is the time interval between 10% and 90% combustion. More information on how to calculate burn duration can be found in Hosseini, Vahid & Checkel, M. (2006), 'Using reformer gas to enhance HCCI combustion of CNG in a CFR Engine', SAE Technical Papers, DOI: 10.4271 / 2006-01-3247. Burn duration (burn duration / combustion duration) can be calculated by the following method: Figure 1 The pressure curve shown in the paper by Hosseini et al. Figure 1 AI10-90 and its relationship with maximum net heat release (HRN) and maximum pressure release (P max ) relationship. Either temperature or pressure can be used to calculate the combustion metric. In this embodiment, the in-cylinder pressure is used to determine the combustion duration.

[0175] Table 5

[0176] fuel <![CDATA[P max ]]> difference% Burning duration (AI 10-90) difference% base fuel 53.41 15.38 Example 2 54.31 1.69％ 15.12 -1.74％ base fuel 53.18 15.37 Example 3 53.29 0.20％ 15.40 0.21％ base fuel 53.21 15.44 Example 4 53.05 -0.30％ 15.47 0.16％ base fuel 53.77 15.27 Example 5 54.29 0.97％ 15.04 -1.52％ base fuel 53.37 15.36 Example 6 54.78 2.64％ 14.74 -3.99％ base fuel 53.55 15.23 Example 7 53.48 -0.14％ 15.40 1.09％

[0177] Figure 3 is P in Table 5 max A graphical representation of the data and showing the average P values ​​generated by burning the base fuel and the test fuels (Examples 2-7) at 1300 rpm and 11.5 bar (IGN 2 degrees BTDC) per day. max .

[0178] Figure 4 is a graphical representation of the Pmax data in Table 5 and shows that P max The average % difference from the base fuel control run on that day for each of Examples 7-11 (where the base fuel results in Table 5 are normalized to zero).

[0179] Figure 5 is a graphical representation of the burn duration data in Table 5 and shows the average % difference in burn duration versus the base fuel control for that day's run for each of Examples 7-11 (where the base fuel results in Table 5 are normalized to zero).

[0180] Examples 8 and 9

[0181] Another set of experiments was conducted on several additional test fuel blends using a base fuel different from the base fuel used in Example 1. The base fuel used in Examples 8 and 9 was a RON 92E10 base gasoline fuel containing 6.8% aromatics, conforming to the prevailing North American specification ASTM D4814, and containing no performance additives. Examples 8 and 9 used the same testing conditions and protocol as described above for Example 1. Table 6 below shows the test fuel blends for Examples 8 and 9, each containing a highly reactive PIB. The molecular weight of the highly reactive PIB used in each fuel is shown in parentheses in column 2 of Table 6. Two different HR-PIBs were used: one with a number average molecular weight of 1000 g / mol, commercially available from BASF under the trade name Glissopal (RTM) 1000, and the other with a number average molecular weight of 2300 g / mol, commercially available from BASF under the trade name Glissopal (RTM) 2300. Table 6 also shows the treat rate, RON, MON, and RON-MON for each test blend.

[0182] Table 6

[0183] Example PIB(MW) PIB dose, ppmw RON MON RON-MON base fuel - - 92.2 86.8 5.4 8 PIB(2300) 5000 92.1 86.7 5.4 9 PIB(1000) 5000 92.0 86.6 5.4

[0184] P was measured for each of Examples 8 and 9 and the base fuel. max and combustion duration, and the results are listed in Table 7 below. Table 7 also lists the P values ​​for each test blend run that day compared to the base fuel control. max and the difference in burning duration in %.

[0185] Table 7

[0186]

[0187] Figure 6 is P in Table 7 max A graphical representation of the data and showing the average P values ​​generated by burning the base fuel and the test fuels (Examples 8-9) at 1300 rpm and 11.5 bar (1 degree IGN after TDC) for each day. max .

[0188] Figure 7 is a graphical representation of the burn duration data in Table 7 and shows the average burn duration versus base fuel run that day at 1300 rpm, 11.5 bar (IGN 1 degree after TDC) for each of Examples 8-9.

[0189] discuss

[0190] The use of 5000 ppmw (by weight) of a low molecular weight, highly reactive PIB having a molecular weight of 1000 g / mol in a gasoline fuel composition has been shown in engine testing (Example 1) to provide increased power (increased P) relative to the base fuel under both low speed / low load and high load / high speed conditions. max ).

[0191] Furthermore, the use of 2500 ppmw and 5000 ppmw of a low molecular weight, highly reactive PIB having a molecular weight of 1000 g / mol in a gasoline fuel composition has been shown to provide increased power (increased P) at low speed / low load conditions in engine testing (Examples 2-4). max ).

[0192] Furthermore, the use of 2500 ppmw and 5000 ppmw of a low molecular weight, highly reactive PIB having a molecular weight of 2300 g / mol in a gasoline fuel composition has been shown to provide increased power (increased P) at low speed / low load conditions in engine testing compared to the base fuel (Examples 5-7). max ). With a lower molecular weight (M w =1000g / mol) of high-reactivity PIB, has a higher molecular weight (M w =2300 g / mol) appears to provide a greater power increase under low speed / low load conditions.

[0193] Furthermore, the use of 5000 ppmw of a highly reactive PIB having a molecular weight of 1000 g / mol in a gasoline fuel composition has been shown to provide reduced burn duration compared to the base fuel (Examples 2-4).

[0194] Furthermore, the use of 2500 ppmw and 5000 ppmw of a highly reactive PIB having a molecular weight of 2300 g / mol in a gasoline fuel composition has been shown to provide reduced burn duration compared to the base fuel (Examples 5-7).

[0195] Furthermore, the use of 5000 ppmw of a highly reactive PIB having a molecular weight of 1000 g / mol in a gasoline fuel composition has been shown to provide increased power (increased Pmax) at low speed / low load conditions in engine testing compared to the base fuel (Example 8).

[0196] Furthermore, the use of 5000 ppmw of a highly reactive PIB having a molecular weight of 2300 g / mol in a gasoline fuel composition has been shown to provide increased power (increased Pmax) at low speed / low load conditions in engine testing compared to the base fuel (Example 9).

[0197] Furthermore, the use of 5000 ppmw of a highly reactive PIB having a molecular weight of 1000 g / mol in a gasoline fuel composition has been shown to provide reduced burn duration compared to the base fuel (Example 8).

[0198] Furthermore, the use of 5000 ppmw of a highly reactive PIB having a molecular weight of 2300 g / mol in a gasoline fuel composition has been shown to provide reduced burn duration compared to the base fuel (Example 9).

Claims

1. A fuel composition, comprising: (a) a gasoline base fuel suitable for use in spark-ignition internal combustion engines; and (b) polybutene polymers; wherein the polybutene polymer has a number average molecular weight in the range of 200 g / mol to 10,000 g / mol, wherein greater than 30% of the polymer molecules in the polybutene polymer have terminal vinylidene groups, and wherein the polybutene polymer is present in an amount of 500 ppm to 5000 ppm by weight of the fuel composition.

2. The fuel composition of claim 1 wherein greater than 40% of the polymer molecules in the polybutene polymer have terminal vinylidene groups.

3. The fuel composition of claim 1 or 2, wherein greater than 50% of the polymer molecules in the polybutene polymer have terminal vinylidene groups.

4. The fuel composition according to any one of claims 1 to 3, wherein the polybutene polymer has a number average molecular weight in the range of 500 g / mol to 5,000 g / mol.

5. The fuel composition of any one of claims 1 to 4, wherein the polybutene polymer has a number average molecular weight in the range of 1000 g / mol to 2,300 g / mol.

6. The fuel composition of any one of claims 1 to 5, wherein the polybutene polymer has a number average molecular weight in the range of 2,300 g / mol to 5,000 g / mol.

7. A fuel composition according to any one of claims 1 to 6, wherein the polybutene polymer is present in an amount of from 1000 ppm to 5000 ppm by weight of the fuel composition.

8. A fuel composition according to any one of claims 1 to 7, wherein the polybutene polymer is present in an amount of from 2500 ppm to 5000 ppm by weight of the fuel composition.

9. The fuel composition of any one of claims 1 to 8, wherein the polybutene polymer is a polyisobutylene polymer.

10. Use of a liquid fuel composition for increasing the power output of an internal combustion engine, wherein the liquid fuel composition comprises: (a) a gasoline base fuel suitable for use in spark-ignition internal combustion engines; and (b) polybutene polymers; wherein the polybutene polymer has a number average molecular weight in the range of 200 g / mol to 10,000 g / mol, and wherein the polybutene polymer is present in an amount of 500 ppm to 5000 ppm by weight of the fuel composition, preferably wherein the polybutene is a highly reactive polybutene, wherein greater than 30% of the polymer molecules in the polyisobutylene polymer have terminal vinylidene groups.

11. Use of a liquid fuel composition for increasing the Pmax of an internal combustion engine, wherein the liquid fuel composition comprises: (a) a gasoline base fuel suitable for use in spark-ignition internal combustion engines; and (b) polybutene polymers; wherein the polybutene polymer has a number average molecular weight in the range of 200 g / mol to 10,000 g / mol, and wherein the polybutene polymer is present in an amount of 500 ppm to 5000 ppm by weight of the fuel composition, preferably wherein the polybutene is a highly reactive polybutene, wherein greater than 30% of the polymer molecules in the polybutene polymer have terminal vinylidene groups.

12. Use of polybutene in a liquid fuel composition for reducing the burning duration, wherein the liquid fuel composition comprises: (a) a gasoline base fuel suitable for use in spark-ignition internal combustion engines; and (b) polybutene polymers; wherein the polybutene polymer has a number average molecular weight in the range of 200 g / mol to 10,000 g / mol, and wherein the polybutene polymer is present in an amount of 500 ppm to 5000 ppm by weight of the fuel composition, preferably wherein the polybutene is a highly reactive polybutene, wherein greater than 30% of the polymer molecules in the polybutene polymer have terminal vinylidene groups.

13. A method of increasing the power output of a spark-ignition internal combustion engine, the method comprising: adding polybutene to a gasoline base fuel to produce a gasoline fuel composition, wherein the polybutene polymer is added at a level of 500 ppm to 5000 ppm by weight of the gasoline fuel composition, wherein the polybutene has a number average molecular weight in the range of 200 g / mol to 10,000 g / mol, and combusting the fuel composition in the spark-ignition internal combustion engine.

14. A method of reducing the combustion duration of a gasoline fuel composition in a spark-ignition internal combustion engine, wherein the method comprises: adding polybutene to a gasoline base fuel to produce a gasoline fuel composition, wherein the polybutene polymer is added at a level of 500 ppm to 5000 ppm by weight of the gasoline fuel composition, wherein the polybutene has a number average molecular weight in the range of 200 g / mol to 10,000 g / mol, and combusting the fuel composition in the spark-ignition internal combustion engine.

15. The method of claim 13 or 14, wherein the polybutene has greater than 30% of the polymer molecules in the polybutene polymer having terminal vinylidene groups.

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