Gasoline composition, method and use

Abstract

A gasoline composition comprising, as an additive, one or more quaternary ammonium salt(s) (i) formed by the reaction of a compound of formula (A): and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1) or (B2): wherein R is an optionally substituted alkyl, alkenyl, aryl or alkylaryl group; R.sup.1 is an alkyl, aryl or alkylaryl group having up to 36 carbon atoms; R.sup.2 and R.sup.3 are the same or different alkyl groups having from 1 to 36 carbon atoms; X is an alkylene group having from 1 to 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R.sup.4 is hydrogen or a C.sub.1 to C.sub.36 alkyl group.

Claims

1. A gasoline composition comprising, as an additive, one or more quaternary ammonium salt(s) (i) formed by the reaction of a compound of formula (A): ##STR00009## and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1) or (B2): ##STR00010## wherein R is an optionally substituted alkyl, alkenyl, aryl or alkylaryl group; R.sup.1 is an alkyl, aryl or alkylaryl group having up to 36 carbon atoms; R.sup.2 and R.sup.3 are the same or different alkyl groups having from 1 to 36 carbon atoms; X is an alkylene group having from 1 to 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R.sup.4 is hydrogen or a C.sub.1 to C.sub.36 alkyl group.

2. A gasoline composition according to claim 1 wherein the compound of formula (A) is an ester of a carboxylic acid having a pK.sub.a of 3.5 or less.

3. A gasoline composition according to claim 1 wherein the quaternary ammonium salt(s) are formed by the reaction of a compound of formula (A) and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1).

4. A gasoline composition according to claim 1 wherein the hydrocarbyl-substituted acylating agent is polyisobutenyl substituted succinic anhydride.

5. A gasoline composition according to claim 1 further comprising one or more additives selected from the group consisting of: a) carrier oils; b) acylated nitrogen compounds which are the reaction product of a carboxylic acid-derived acylating agent and an amine; c) hydrocarbyl-substituted amines wherein the hydrocarbyl substituent is substantially aliphatic and contains at least 8 carbon atoms; d) Mannich base additives comprising nitrogen-containing condensates of a phenol, aldehyde and primary or secondary amine; and e) aromatic esters of a polyalkylphenoxyalkanol.

6. A gasoline composition according to claim 5 wherein component (a) is selected from the group consisting of polyethers and polyetheramines.

7. A gasoline composition according to claim 5 wherein component (d) comprises the reaction product of formaldehyde, an ethylene or polyethylene polyamine, and para-substituted monoalkyl phenol.

8. An additive package which upon addition to gasoline provides a composition as claimed in claim 1.

9. A method of improving the performance of a gasoline engine comprising adding to gasoline one or more quaternary ammonium salt(s) formed by the reaction of a compound of formula (A): ##STR00011## and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1) or (B2): ##STR00012## wherein R is an optionally substituted alkyl, alkenyl, aryl or alkylaryl group; R.sup.1 is an alkyl, aryl or alkylaryl group having up to 36 carbon atoms; R.sup.2 and R.sup.3 are the same or different alkyl groups having from 1 to 36 carbon atoms; X is an alkylene group having from 1 to 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R.sup.4 is hydrogen or a C.sub.1 to C.sub.36 alkyl group; and combusting the additised gasoline.

10. A method of controlling deposits in a gasoline engine comprising adding to gasoline one or more quaternary ammonium salt(s) formed by the reaction of a compound of formula (A): ##STR00013## and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1) or (B2): ##STR00014## wherein R is an optionally substituted alkyl, alkenyl, aryl or alkylaryl group; R.sup.1 is an alkyl, aryl or alkylaryl group having up to 36 carbon atoms; R.sup.2 and R.sup.3 are the same or different alkyl groups having from 1 to 36 carbon atoms; X is an alkylene group having from 1 to 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R.sup.4 is hydrogen or a C.sub.1 to C.sub.36 alkyl group; and combusting the additised gasoline.

11. A method according to claim 10, wherein said controlling deposits comprises reducing existing deposits or reducing deposit formation.

12. A method according to claim 9, where the gasoline engine is a direct injection spark ignition gasoline engine.

13. A method of controlling deposits and/or of improving the efficiency in a spark ignition gasoline engine, the method comprising adding into the gasoline to be combusted: (i) one or more quaternary ammonium salt(s) as defined in claim 1, and (ii) optionally, one or more additional components selected from a)-e) as defined in claim 5.

Description

EXAMPLES

Example 1

(1) Additive A, the reaction product of a hydrocarbyl substituted acylating agent and a compound of formula (B1) was prepared as follows:

(2) 523.88 g (0.425 moles) PIBSA (made from 1000 MW PIB and maleic anhydride) and 373.02 g Caromax 20 were charged to 1 liter vessel. The mixture was stirred and heated, under nitrogen to 50 C. 43.69 g (0.425 moles), DMAPA was added and the mixture heated to 160 C. for 5 hours, with concurrent removal of water using a Dean-Stark apparatus. Additive A was believed to be approximately 60% active material and 40% solvent.

(3) [Note: PIB herein means polyisobutene; PIBSA means polyisobutenyl-substituted succinic anhydride; DMAPA means dimethylaminopropylamine]

Example 2

(4) Additive B, an additive comprising a quaternary ammonium salt(s) additive of the present invention was prepared as follows:

(5) 588.24 g (0.266 moles) of Additive A mixed with 40.66 g (0.266 moles) methyl salicylate under nitrogen. The mixture was stirred and heated to 160 C. for 16 hours.

(6) The product mixture of this reaction was used without further processing as additive B and contained the quaternary ammonium salt(s) additive of the present invention, together with any unreacted raw materials, other reaction products and solvent. The solvent content of Additive B was approximately 35%.

Example 3

(7) Gasoline compositions were prepared comprising the additives listed in Table 2, added to aliquots all drawn from a common batch of DF12 reference fuel.

(8) Additive C is a carrier oil compound a), namely a linear C13 linear alcohol polyether with 13 PO units.

(9) Table 1 below shows the specification for the DF12 reference fuel.

(10) TABLE-US-00001 TABLE 1 Parameter Units Result Min. Max. Method RON 99.2 95.0 EN 25164 MON 88.9 85.0 EN 25163 Density 15 C. kg/m.sup.3 739.9 720.0 775.0 EN ISO 12185 Vapour pressure, kPa 59.4 60.0 90.0 EN 13016-1 DVPE Distillation I.B.P. C. 32.4 EN ISO 3405 Dist. 70 C. % v/v 27.1 22.0 50.0 EN ISO 3405 Dist. 100 C. % v/v 44.9 46.0 71.0 EN ISO 3405 Dist. 150 C. % v/v 85.0 75.0 EN ISO 3405 Distillation F.B.P. C. 197.8 210.0 EN ISO 3405 Dist. Residue % v/v 1.0 2.0 EN ISO 3405 Benzene % v/v 0.3 5.0 EN 236 Oxygenates ASTM D 4815 Methanol % v/v <0.1 3.0 Ethanol % v/v <0.1 5.0 TBA % v/v <0.1 7.0 i-Propanol % v/v <0.1 10.0 i-Butanol % v/v <0.1 7.0 MTBE % v/v <0.1 15.0 Oxygenates total % v/v <0.1 Oxygen content % m/m <0.1 2.7 FIA ASTM D 1319 Aromatics % v/v 31.2 42.0 Olefins % v/v 6.2 18.0 Saturates % v/v 62.2 Sulphur content mg/kg 19 EN 24260 Lead content mg/l <5 5 EN 237 Oxidation stability min. >1200 360 EN ISO 7536 Unwashed gum mg/100 ml 2.0 EN ISO 6246 Solvent washed mg/100 ml 0.2 5 EN ISO 6246 gum Hydrogen content % m/m 13.38 ASTM D 3343 Carbon content % m/m 86.62 ASTM D 3343 Carbon/Hydrogen 6.47:1 ASTM D 3343 ratio Hydrogen/Carbon 0.155:1 ASTM D 3343 ratio Net heat value MJ/kg 42.923 ASTM D 3338 Net heat value Btu/lb 18450 ASTM D 3338

Example 4

(11) Fuel compositions 1 to 3 listed in table 1 were tested according to the CEC F-05-93 Intake Valve Deposit Test Method.

(12) This test method is designed to evaluate the propensity of gasoline or gasoline additive formulations to prevent intake valve deposits in fuel injected engines.

(13) The engine is an in-line, four cylinder, four stroke 2.3 liter overhead camshaft mechanical/electronic fuel injection engine. After running-in (new engine only) and checking, the engine is operated for a period of 60 hours under cyclic conditions, simulating stop-go operation, with the inlet valves pegged to prevent rotation. The ability of a gasoline or gasoline formulation to influence deposit formation on the inlet valves is determined The results are expressed by the weight of the deposits accumulated during the test on the intake valves and in terms of deposit merit ratings based on a scale from 4.5 (extremely heavy inlet valve deposits) to 10 (clean inlet valve).

(14) The results are presented as the average, over 4 valves.

(15) Full details of the CEC F-05-93 test method can be obtained from the CEC (The Coordinating European Council for the Development of Performance Tests for Fuels, Lubricants and Other Fluids, having its registered office in Brussels, Belgium).

(16) Results are shown in Table 2 below

(17) TABLE-US-00002 TABLE 2 Additive B Additive C Valve Weight Composition (mg/litre) (mg/litre) (mg/valve) Valve Rating Basefuel 358.4 1 500 0.8 9.96 2 250 150 65.2 9.51 3 167 291 8.73 4 250 185.4 9.90

(18) The amounts stated above refer to the reaction products of Examples 2 and 3 as such including solvents (when present).

Example 5

(19) A second sample of quaternary ammonium salt additive of the present invention was prepared, Additive D.

(20) Additive D was prepared in a similar way to the additives described above, using the following raw materials: 1000 MW PIB, (45.4 parts weight), maleic anhydride (4.2 parts weight), DMAPA (4.2 parts weight), solvent (39.9 parts weight), methyl salicylate (6.3 parts weight). The finished product contained approximately 40% solvent.

Example 6

(21) Additive E was a hydrocarbyl substituted amine comprising approximately 45% by weight of a polyisobutenamine having a molecular weight of 1000 and approximately 55% by weight solvent. Additive E was a commercially available product sold under the trade name of Kerocom PIBA.

Example 7

(22) Additive F was prepared as follows.

(23) 1000 mwt high reactive PIB derived PIBSA (4712 g) was stirred with aromatic solvent (Caromax 20, 3337 g) in a 10 liter oil jacketed reactor equipped with an overhead stirrer, thermometer and Dean & Stark trap. A polyethylene polyamine mixture of average composition approximating to tetraethylene pentamine (363.2 g, 1.92 mol) was added in one aliquot with continued stirring at 50 C. An immediate exotherm was noted. The reaction mix was heated to 160 C. for three hours whilst removing water via a Dean & Stark trap. 8343 g of a clear brown liquid product was obtained. Additive F was found to contain 60% non-volatiles and 40% solvent.

Example 8a

(24) Additive G was prepared as follows:

(25) Phenol alkylated with 1000 MW PIB (356.3 g, 0.326 moles) and Caromax 20 (185.7 g) were charged to a reactor and mixed with constant stirring at ambient temperature below 30 deg C. under a nitrogen purge. Ethylenediamine (19.6 g, 0.326 moles) was then charged to the reactor. The mixture was heated to a temperature of 95 deg C. Formalin (26.7 g, 0.326 moles, 36.6 wt % formaldehyde in water and methanol) was charged to the reactor over 1 hr at 95-100 deg C. A mild exotherm was noted. Following the addition the mixture was held at 95 deg C. for 1 hr. The reaction mixture was heated to reflux. The azeotropic blend of water and solvent was removed continuously over a period lasting 2 hours. The temperature was increased as required to sustain removal of water, then the reaction mixture heated gradually to 150 deg C. The product dissolved in Caromax 20 was obtained as a clear amber solution (561.9 g). Additive G was found to contain 65% non-volatiles and 35% solvent.

Example 8b

(26) Additive J is a carrier oil compound, namely a hydrocarbyl-substituted polyoxyalkylene amine comprising approximately 53% non-volatiles and 47% solvent. This polyetheramine was a commercial product obtained under the trade name Ultrazol and comprised a polypropylene glycol backbone capped with a C12-C15 ether substituent and a 3-aminopropyl substituent.

Example 9

(27) Gasoline compositions were prepared comprising the additives listed in Table 4, added to aliquots all drawn from a common batch of DF12 reference fuel.

(28) Additive H is a carrier oil compound a), namely a linear C10 alcohol polyether with 24 PO units. Additive H did not contain any solvents.

(29) Table 3 below shows the specification for the DF12 reference fuel.

(30) TABLE-US-00003 TABLE 3 Parameter Units Result Min. Max. Method RON 96.6 95.0 EN ISO 5164 MON 86.9 85.0 EN ISO 5163 Density at 15 C. kg/m.sup.3 733.6 720.0 775.0 EN ISO 12185 DVPE kPa 86.3 60.0 90.0 EN 13016-1 Distillation IBP C. 28.4 EN ISO 3405 Dist. 70 C. % vol 33.2 22.0 50.0 EN ISO 3405 Dist. 100 C. % vol 52.6 46.0 71.0 EN ISO 3405 Dist. 150 C. % vol 93.5 75.0 EN ISO 3405 Distillation FBP C. 182.4 210.0 EN ISO 3405 Dist. Residue % vol 1.0 2.0 EN ISO 3405 Olefins % vol 7.5 18.0 EN ISO 22854 Aromatics % vol 32.1 42.0 EN ISO 22854 Saturates % vol 59.5 EN ISO 22854 Benzene % vol 0.75 5.00 EN ISO 22854 Methanol % vol <0.1 3.00 EN ISO 22854 Ethanol % vol 0.90 1.00 EN ISO 22854 Iso-Propanol % vol <0.1 10.00 EN ISO 22854 Iso-Butanol % vol <0.1 7.00 EN ISO 22854 TBA % vol <0.1 7.00 EN ISO 22854 MTBE % vol <0.1 15.00 EN ISO 22854 Oxygenates % vol 0.9 EN ISO 22854 Oxygen content % wt 0.3 2.7 EN ISO 22854 Sulphur mg/kg 5.8 EN ISO 20846 Lead mg/l <2.5 5.0 EN 237 Oxidation stability min >1200 360 EN ISO 7536 Unwashed Gum mg/100 ml 5 EN ISO 6246 Solvent washed mg/100 ml 3 5 EN ISO 6246 gum Hydrogen % wt 13.3 ASTM D 3343 Carbon % wt 86.35 ASTM D 3343 Carbon/Hydrogen 6.49 ASTM D 3343 ratio Hydrogen/Carbon 0.154 ASTM D 3343 ratio Net heating value MJ/kg 42,678 ASTM D 3338 Net heating value Btu/lb 18347 ASTM D 3338

Example 10

(31) The fuel compositions listed in Table 4 were tested according to the CEC F-05-93 Intake Valve Deposit Test Method referred to in Example 4.

(32) TABLE-US-00004 TABLE 4 Valve Additive D Additive E Additive F Additive G Additive H Additive J Weight Valve Composit'n (mg/litre) (mg/litre) (mg/litre) (mg/litre) (mg/litre) (mg/litre) (mg/valve) Rating DF12 fuel 714.8 7.0 5 150 150 95.9 9.2 6 75 75 150 30.4 9.5 7 75 75 150 170.6 8.9 8a 75 75 150 22.1 9.8 8b 75 225 0.4 9.95

(33) In each case, the additive concentration is measured in mg/liter of the non volatile material.

Example 11

(34) Additive I, a quaternary ammonium salt additive of the present invention was prepared as follows:

(35) 33.9 kg (27.3 moles) of a polyisobutyl-substituted succinic anhydride having a PIB molecular weight of 1000 was heated to 90 C. 2.79 kg (27.3 moles) dimethylaminopropylamine was added and the mixture stirred at 90 to 100 C. for 1 hour. The temperature was increased to 140 C. for 3 hours with concurrent removal of water. 25 kg of 2-ethyl hexanol was added, followed by 4.15 kg methyl salicylate (27.3 moles) and the mixture maintained at 140 C. for 9.5 hours.

(36) Additive I was found to contain approximately 61% non-volatile material and 39% solvent.

Example 12

(37) Additive K, a quaternary ammonium salt additive which may be used in the present invention was prepared as follows.

(38) 45.68 g (0.0375 moles) of Additive A was mixed with 15 g (0.127 moles) dimethyl oxalate and 0.95 g octanoic acid. The mixture was heated to 120 C. for 4 hours. Excess dimethyl oxalate was removed under vacuum. 35.10 g of product was diluted with 23.51 g Caromax 20.

Example 13

(39) Additive L, a quaternary ammonium salt additive which may be used in the present invention was prepared as follows:

(40) 315.9 g (0.247 moles) of a polyisobutyl-substituted succinic anhydride having a PIB molecular weight of 1000 was mixed with 66.45 g (0.499 moles) 2-(2-dimethylaminoethoxy) ethanol and 104.38 g Caromax 20. The mixture was heated to 200 C. with removal of water. The solvent was removed under vacuum. 288.27 g (0.191 mol) of this product was reacted with 58.03 g (0.381 mol) methyl salicylate at 150 C. overnight and then 230.9 g Caromax 20 was added.

Example 14

(41) Additive M, a quaternary ammonium salt additive which may be used in the present invention was prepared as follows:

(42) 33.9 kg (27.3 moles) of a polyisobutyl-substituted succinic anhydride having a PIB molecular weight of 1000 was heated to 90 C. 2.79 kg (27.3 moles) dimethylaminopropylamine was added and the mixture stirred at 90 to 100 C. for 1 hour. The temperature was increased to 140 C. for 3 hours with concurrent removal of water. 25 kg of 2-ethyl hexanol was added, followed by 4.15 kg methyl salicylate (27.3 moles) and the mixture maintained at 140 C. for 9.5 hours.

Example 15

(43) Additive N, a quaternary ammonium salt additive which may be used in the present invention was prepared as follows:

(44) A polyisobutyl-substituted succinic anhydride having a PIB molecular weight of 260 was reacted with dimethylaminopropylamine using a method analogous to that described in example 10. 213.33 g (0.525 moles) of this material was added to 79.82 (0.525 moles) methyl salicylate and the mixture heated to 140 C. for 24 hours before the addition of 177 g 2-ethylhexanol.

Example 16

(45) Additive O, a quaternary ammonium salt additive which may be used in the present invention was prepared as follows:

(46) A reactor was charged with 201.13 g (0.169 mol) of Additive A, 69.73 g (0.59 mol) dimethyl oxalate and 4.0 g 2-ethyl hexanoic acid. The mixture was heated to 120 C. for 4 hours. Excess dimethyl oxalate was removed under vacuum and 136.4 g Caromax 20 was added.

Example 17

(47) Additive P, a quaternary ammonium salt additive which may be used in the present invention was prepared as follows:

(48) 251.48 g (0.192 mol) of a polyisobutyl-substituted succinic anhydride having a PIB molecular weight of 1000 and 151.96 g toluene were heated to 80 C. 35.22 g (0.393 mol) N,N-dimethyl-2-ethanolamine was added and the mixture heated to 140 C. 4 g of Amberlyst catalyst was added and mixture reacted overnight before filtration and removal of solvent. 230.07 g (0.159 mol) of this material was reacted with 47.89 g (0.317 mol) methyl salicylate at 142 C. overnight before the addition of 186.02 g Caromax 20.

Example 18

(49) Additive Q, a quaternary ammonium salt additive of the present invention was prepared as follows:

(50) A polyisobutyl-substituted succinic anhydride having a PIB molecular weight of 1300 was reacted with dimethylaminopropylamine using a method analogous to that described in Example 14. 20.88 g (0.0142 mol) of this material was mixed with 2.2 g (0.0144 mol) methyl salicylate and 15.4 g 2-ethylhexanol. The mixture was heated to 140 C. for 24 hours.

Example 19

(51) Additive R, a quaternary ammonium salt additive which may be used in the present invention was prepared as follows:

(52) A polyisobutyl-substituted succinic anhydride having a PIB molecular weight of 2300 was reacted with dimethylaminopropylamine using a method analogous to that described in Example 14. 23.27 g (0.0094 mol) of this material was mixed with 1.43 g (0.0094 mol) methyl salicylate and 16.5 g 2-ethylhexanol. The mixture was heated to 140 C. for 24 hours.

Example 20

(53) Additive S, a quaternary ammonium salt additive which may be used in the present invention was prepared as follows:

(54) A polyisobutyl-substituted succinic anhydride having a PIB molecular weight of 750 was reacted with dimethylaminopropylamine using a method analogous to that described in Example 14. 31.1 g (0.034 mol) of this material was mixed with 5.2 g (0.034 mol) methyl salicylate and 24.2 g 2-ethylhexanol. The mixture was heated to 140 C. for 24 hours.

Example 21

(55) Additive T, a quaternary ammonium salt additive which may be used in the present invention was prepared as follows:

(56) 61.71 g (0.0484 mol) of a polyisobutyl-substituted succinic anhydride having a PIB molecular weight of 1000 was heated to 74 C. 9.032 g (0.0485 mol) dibutylaminopropylamine was added and the mixture heated to 135 C. for 3 hours with removal of water. 7.24 g (0.0476 mol) methyl salicylate was added and the mixture reacted overnight before the addition of 51.33 g Caromax 20.

Example 22

(57) Additive U, a quaternary ammonium salt additive which may be used in the present invention was prepared as follows:

(58) 157.0 g (0.122 mol) of a polyisobutyl-substituted succinic anhydride having a PIB molecular weight of 1000 and 2-ethylhexanol (123.3 g) were heated to 140 C. Benzyl salicylate (28.0 g, 0.123 mol) added and mixture stirred at 140 C. for 24 hours.

Example 23

(59) Additive V, a quaternary ammonium salt additive which may be used in the present invention was prepared as follows:

(60) 18.0 g (0.0138 mol) of Additive A and 2-ethylhexanol (12.0 g) were heated to 140 C. Methyl 2-nitrobenzoate (2.51 g, 0.0139 mol) was added and the mixture stirred at 140 C. for 12 hours.

Example 24

(61) Basefuel

(62) An E5 98 RON basefuel was prepared by blending 95% by volume of a reference gasoline RF-83-A-91/B16 with 5% by volume of dehydrated ethanol denatured with cyclohexane. Analytical data for the reference gasoline is given in Table 5.

(63) TABLE-US-00005 TABLE 5 Analysis of RF-83-A-91/B16 Property Result Density at 15 C. 750 kg/m3 Reid Vapour Pressure 598 mbar Distillation IBP 35 C. 10% Vol 50 C. 50% Vol 105 C. 90% Vol 161 C. FBP 207 C. Composition Saturates 49.8% Vol Olefins 12.5% Vol Aromatics 37.7% Vol Sulphur 7 mg/kg Lead <0.001 g/l RON 97.1 MON 86.2 Number RON = Research Octane MON = Motor Octane Number
Test Fuel

(64) A test fuel was prepared by blending 320 mg/l of Additive I into the basefuel. 320 mg/l of additive I is equivalent to approximately 195 mg/l on a non volatiles basis.

(65) GDI Engine Tests

(66) An engine test was performed using the APL GDI Nozzle Coking test.

(67) This test was designed to check the ability of fuels and/or additives to keep injector nozzles of GDI-engines clean. The engine used is the VW FSI 036.K/ARR/VW-1,4 liter VW Lupo 2002. Engine details are as follows: Number of Cylinders: 4 Displacement: 1398 cm3 Nom. Power: 77 kW Nom. Torque: 130 Nm Fuel: RON 98 Spark Plugs: VAG 101 000 068 AA Coolant: 50% Water/50% G 12 liters VW TL 774/D

(68) The injectors have one sprayhole with 0.55 mm diameter.

(69) The test uses a 4 stage alternating program, including part load with stratified combustion and full load at maximum torque speed. Each cycle of 4 stages has a 30 min running time. The test duration is around 50 hours (=100 cycles). The total fuel consumption is around 750 liters per test. The selected engine oil is LM Top Tec 4200 5W-30, a first fill oil for this engine type.

(70) After the test, the engine inlet manifold is disassembled, so the nozzles can be removed for evaluation.

(71) The deposits are rated visually, following a scale from 0 to 7.

(72) 0: Clean or a very limited number of single spots visible

(73) 7: Surface completely covered with deposits with thickness and structured surface

(74) The rating shows the best existing surface/deposit formation called Minimum, the worst case of deposit formation called Maximum and an Average value, that reflects the overall appearance and distribution of little and heavy deposits.

(75) The evaluation is made by a Scanning Electron Microscope (SEM) that shows the topography and distribution of the deposits around and in the sprayhole. An analysis of the injector deposits by Energy Dispersive X-Ray (EDX) Elemental Analysis is also performed. In particular, the iron content is considered to be the most important parameter with new and clean nozzles showing values around 50% iron and injectors with heavy deposits showing values around 5% iron.

(76) Results are shown in Tables 6 and 7.

(77) TABLE-US-00006 TABLE 6 Visual Rating of Injection Nozzle Orifice Deposits Min Average Max Clean Nozzle 0 0 1 Base Fuel Reference 6 7 7 Nozzle 1 0 0 0 Nozzle 2 0 0 0 Nozzle 3 0 0 1 Nozzle 4 0 0 0 Average 0 0 0

(78) TABLE-US-00007 TABLE 7 EDX Elemental Analysis% Weight Iron % Weight Iron Clean Nozzle 50% Base Fuel Reference 5% Nozzle 1 52.41% Nozzle 2 54.59% Nozzle 3 46.12% Nozzle 4 55.22% Average 52.08%

Example 25

(79) A second GDI test was run as a clean up test.

(80) In this example, a different batch of E5 98 RON basefuel was prepared by blending 95% by volume of a reference gasoline RF-83-A-91/B17 with 5% by volume of dehydrated ethanol denatured with cyclohexane. Analytical data for the reference gasoline is given in Table 8.

(81) TABLE-US-00008 TABLE 8 Analysis of RF-83-A-91/B17 Property Result Density at 15 C. 752.5 kg/mJ Reid Vapour Pressure 601 mbar Distillation IBP 37 C. 10% Vol 47 C. 50% Vol 106 C. 90% Vol 156 C. FBP 190 C. Composition Saturates 49.2% Vol Olefins 11.9% Vol Aromatics 38.9% Vol Sulphur 3 mg/kg Lead <0.005 g/l RON 97.7 MON 85.4 RON = Research Octane Number MON = Motor Octane Number
Test Fuel

(82) A test fuel was prepared by blending 500 mg/l of Additive I into the basefuel. 500 mg/l of Additive I is equivalent to approximately 305 mg/l on a non volatiles basis.

(83) An engine test of the type described above was performed using the APL GDI Nozzle Coking test of Example 24 but instead of using clean injectors at the start of test, a dirty set of injectors were used.

(84) The injectors used at the start of the test had an average visual rating of 5.

(85) Results are shown in Tables 9 and 10.

(86) TABLE-US-00009 TABLE 9 Visual Rating of Injection Nozzle Orifice Deposits Min Average Max Clean Nozzle 0 0 1 Base Fuel Reference 6 7 7 Injectors at start of test 5 Nozzle 1 0 0 1 Nozzle 2 0 0 1 Nozzle 3 0 0 0 Nozzle 4 0 0 0 Average 0

(87) TABLE-US-00010 TABLE 10 EDX Elemental Analysis% Weight Iron % Weight Iron Clean Nozzle 50% Base Fuel Reference 5% Nozzle 1 52.56% Nozzle 2 47.91% Nozzle 3 50.38% Nozzle 4 51.89% Average 50.69%