Fuel Composition Comprising Detergent and Quaternary Ammonium Salt Additive

Abstract

A method of reducing deposits in a diesel engine, the method comprising combusting in the engine a diesel fuel composition comprising a detergent additive which is not a quaternary ammonium salt or a Mannich reaction product; and a quaternary ammonium salt additive comprising the reaction product of nitrogen containing species having at least one tertiary amine group and a quaternizing agent; wherein the nitrogen containing species is selected from: (i) the reaction product of a hydrocarbyl-substituted acylating agent and a compound comprising at least one tertiary amine group and a primary amine, secondary amine or alcohol group; (ii) a Mannich reaction product comprising a tertiary amine group; and (v) a polyalkylene substituted amine having at least one tertiary amine group.

Claims

1. A method of reducing deposits in a diesel engine, the method comprising combusting in the engine a diesel fuel composition comprising a detergent additive which is not a quaternary ammonium salt or a Mannich reaction product; and a quaternary ammonium salt additive comprising the reaction product of nitrogen containing species having at least one tertiary amine group and an ester quaternizing agent; wherein the nitrogen containing species is selected from: (i) the reaction product of a hydrocarbyl-substituted acylating agent and a compound comprising at least one tertiary amine group and a primary amine, secondary amine or alcohol group; (ii) a Mannich reaction product comprising a tertiary amine group; and (iii) a polyalkylene substituted amine having at least one tertiary amine group.

2. A method according to claim 1 wherein formation of deposits is inhibited or prevented to provide a keep clean performance.

3. A method according to claim 1 wherein existing deposits are removed to provide a clean up performance.

4. A method according to claim 1 wherein the quaternizing agent is an ester of a carboxylic acid.

5. A method according to claim 1 wherein the nitrogen containing species comprises a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (I) or (II): ##STR00015## wherein R.sup.2 and R.sup.3 are the same or different alkyl groups having from 1 to 22 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.22 alkyl group.

6. A method according to claim 1 wherein the quaternizing agent comprises a compound of formula (III): ##STR00016## wherein R is a substituted alkyl, alkenyl, aryl or alkylaryl group; and R.sup.1 is a C.sub.1 to C.sub.22 alkyl, aryl or alkylaryl group.

7. A method according to claim 1 wherein the detergent additive is selected from one or more of: (a) the reaction product of a carboxylic acid-derived acylating agent and an amine; (b) the reaction product of a carboxylic acid-derived acylating agent and hydrazine; (c) a salt formed by the reaction of a carboxylic acid with di-n-butylamine or tri-n-butylamine; (d) the reaction product of a hydrocarbyl-substituted dicarboxylic acid or abhydride and an amine compound or salt which product comprises at least one amino triazole group; and (e) a polyaromatic detergent additive.

8. A method according to claim 7 wherein the detergent additive comprises component (a) and is made by reacting a poly(isobutene)-substituted succinic acid-derived acylating agent wherein the poly(isobutene) substituent has between about 12 to about 200 carbon atoms with a mixture of ethylene polyamines having 3 to about 9 amino nitrogen atoms per ethylene polyamine and about 1 to about 8 ethylene groups.

9. A method according to claim 7 wherein the detergent additive comprises component (b) and is the reaction product between a hydrocarbyl-substituted succinic acid or anhydride and hydrazine.

10. A method according to claim 7 wherein the detergent additive comprises component (c) and is the di-n-butylamine or tri-n-butylamine salt of a fatty acid of the formula [R(COOH).sub.x].sub.y, where each R is a independently a hydrocarbon group of between 2 and 45 carbon atoms, and x is an integer between 1 and 4.

11. A method according to claim 7 wherein the detergent additive comprises component (d) and is the reaction product of an amine compound having the formula: ##STR00017## and a hydrocarbyl carbonyl compound of the formula: ##STR00018## wherein R is selected from the group consisting of a hydrogen and a hydrocarbyl group containing from about 1 to about 15 carbon atoms; R.sup.1 is selected from the group consisting of hydrogen and a hydrocarbyl group containing from about 1 to about 20 carbon atoms; and R.sup.2 is a hydrocarbyl group having a number average molecular weight ranging from about 100 to about 5000.

12. A method according to claim 7 wherein the detergent additive comprises component (e) and comprises at least one compound of formula (IV) and/or formula (V): ##STR00019## wherein each Ar independently represents an aromatic moiety having 0 to 3 substituents selected from the group consisting of alkyl, alkoxy, alkoxyalkyl, aryloxy, aryloxyalkyl, hydroxy, hydroxyalkyl, halo and combinations thereof; each L is independently a linking moiety comprising a carbon-carbon single bond or a linking group; each Y is independently OR.sup.1 or a moiety of the formula H(O(CR.sup.1.sub.2).sub.n).sub.yX, wherein X is selected from the group consisting of (CR.sup.1.sub.2).sub.2, O and S: R.sup.1 and R.sup.1 are each independently selected from H, C.sub.1 to C.sub.6 alkyl and aryl; R.sup.1 is selected from C.sub.1 to C.sub.100 alkyl and aryl; z is 1 to 10; n is 0 to 10 when X is (CR.sup.1.sub.2).sub.2, and 2 to 10 when X is O or S; y is 1 to 30; each a is independently 0 to 3, with the proviso that at least one Ar moiety bears at least one group Y; and m is 1 to 100; ##STR00020## wherein each Ar independently represents an aromatic moiety having 0 to 3 substituents selected from the group consisting of alkyl, alkoxy, alkoxyalkyl, hydroxy, hydroxyalkyl, acyloxy, acyloxyalkyl, acyloxyalkoxy, aryloxy, aryloxyalkyl, aryloxyalkoxy, halo and combinations thereof; each L is independently a linking moiety comprising a carbon-carbon single bond or a linking group; each Y is independently a moiety of the formula ZO or Z(O(CR.sup.2.sub.2).sub.n).sub.yX, wherein X is selected from the group consisting of (CR.sup.2.sub.2).sub.z, O and S; R.sup.2 and R.sup.2 are each independently selected from H, C.sub.1 to C.sub.6 alkyl and aryl; z is 1 to 10; n is 0 to 10 when X is (CR.sup.2.sub.2).sub.z, and 2 to 10 when X is O or S; y is 1 to 30; Z is H, an acyl group, a polyacyl group, a lactone ester group, an acid ester group, an alkyl group or an aryl group; each a is independently 0 to 3, with the proviso that at least one Ar moiety bears at least one group Y in which Z is not H; and m is 1 to 100.

13. A method according to claim 1 wherein the quaternizing agent is selected from dimethyl oxalate, methyl 2-nitrobenzoate and methyl salicylate.

14. A method according to claim 1 wherein the diesel engine has a high pressure fuel system.

15. A diesel fuel composition comprising a detergent additive which is not a quaternary ammonium salt or a Mannich reaction product; and a quaternary ammonium salt additive comprising the reaction product of nitrogen containing species having at least one tertiary amine group and an ester quaternizing agent; wherein the nitrogen containing species is selected from: (i) the reaction product of a hydrocarbyl-substituted acylating agent and a compound comprising at least one tertiary amine group and a primary amine, secondary amine or alcohol group; (ii) a Mannich reaction product comprising a tertiary amine group; and (iii) a polyalkylene substituted amine having at least one tertiary amine group.

16. A diesel fuel composition according to claim 15 wherein the nitrogen containing species comprises a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (I) or (II): ##STR00021## wherein R.sup.2 and R.sup.3 are the same or different alkyl groups having from 1 to 22 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.22 alkyl group.

17. A diesel fuel composition according to claim 15 wherein the quaternizing agent comprises a compound of formula (III): ##STR00022## wherein R is a substituted alkyl, alkenyl, aryl or alkylaryl group; and R.sup.1 is a C.sub.1 to C.sub.22 alkyl, aryl or alkylaryl group.

18. A diesel fuel composition according to claim 15 wherein the detergent additive is selected from one or more of: (a) the reaction product of a carboxylic acid-derived acylating agent and an amine; (b) the reaction product of a carboxylic acid-derived acylating agent and hydrazine; (c) a salt formed by the reaction of a carboxylic acid with di-n-butylamine or tri-n-butylamine; (d) the reaction product of a hydrocarbyl-substituted dicarboxylic acid or abhydride and an amine compound or salt which product comprises at least one amino triazole group; and (e) a polyaromatic detergent additive.

19. A diesel fuel composition according to claim 18 wherein the detergent additive comprises component (a) and is made by reacting a poly(isobutene)-substituted succinic acid-derived acylating agent, wherein the poly(isobutene) substituent has between about 12 to about 200 carbon atoms with a mixture of ethylene polyamines having 3 to about 9 amino nitrogen atoms per ethylene polyamine and about 1 to about 8 ethylene groups.

20. A diesel fuel composition according to claim 18 wherein the detergent additive comprises component (b) and is the reaction product of a hydrocarbyl-substituted succinic acid or anhydride, and hydrazine.

21. A diesel fuel composition according to claim 18 wherein the detergent additive comprises component (c) and is the di-n-butylamine or tri-n-butylamine salt of a fatty acid of the formula [R(COOH).sub.x].sub.y, where each R is independently a hydrocarbon group of between 2 and 45 carbon atoms, and x is an integer between 1 and 4.

22. A diesel fuel composition according to claim 18 wherein the detergent additive comprises component (d) and is the reaction product of an amine compound having the formula: ##STR00023## and a hydrocarbyl carbonyl compound of the formula: ##STR00024## wherein R is selected from the group consisting of a hydrogen and a hydrocarbyl group containing from about 1 to about 15 carbon atoms; R.sup.1 is selected from the group consisting of hydrogen and a hydrocarbyl group containing from about 1 to about 20 carbon atoms; and R.sup.2 is a hydrocarbyl group having a number average molecular weight ranging from about 100 to about 5000.

23. A diesel fuel composition according to claim 18 wherein the detergent additive comprises component (e) and comprises at least one compound of formula (IV) and/or formula (V): ##STR00025## wherein each Ar independently represents an aromatic moiety having 0 to 3 substituents selected from the group consisting of alkyl, alkoxy, alkoxyalkyl, aryloxy, aryloxyalkyl, hydroxy, hydroxyalkyl, halo and combinations thereof; each L is independently a linking moiety comprising a carbon-carbon single bond or a linking group; each Y is independently OR.sup.1 or a moiety of the formula H(O(CR.sup.1.sub.2).sub.n).sub.yX, wherein X is selected from the group consisting of (CR.sup.1.sub.2).sub.2, O and S; R.sup.1 and R.sup.1 are each independently selected from H, C.sub.1 to C.sub.6 alkyl and aryl; R.sup.1 is selected from C.sub.1 to C.sub.100 alkyl and aryl; z is 1 to 10; n is 0 to 10 when X is (CR.sup.1.sub.2).sub.2, and 2 to 10 when X is O or S; and y is 1 to 30; each a is independently 0 to 3, with the proviso that at least one Ar moiety bears at least one group Y; and m is 1 to 100; ##STR00026## wherein each Ar independently represents an aromatic moiety having 0 to 3 substituents selected from the group consisting of alkyl, alkoxy, alkoxyalkyl, hydroxy, hydroxyalkyl, acyloxy, acyloxyalkyl, acyloxyalkoxy, aryloxy, aryloxyalkyl, aryloxyalkoxy, halo and combinations thereof; each L is independently a linking moiety comprising a carbon-carbon single bond or a linking group; each Y is independently a moiety of the formula ZO or Z(O(CR.sup.2.sub.2).sub.n).sub.yX, wherein X is selected from the group consisting of (CR.sup.2.sub.2).sub.z, O and S; R.sup.2 and R.sup.2 are each independently selected from H, C.sub.1 to C.sub.6 alkyl and aryl; z is 1 to 10; n is 0 to 10 when X is (CR.sup.2.sub.2).sub.z, and 2 to 10 when X is O or S; y is 1 to 30; Z is H, an acyl group, a polyacyl group, a lactone ester group, an acid ester group, an alkyl group or an aryl group; each a is independently 0 to 3, with the proviso that at least one Ar moiety bears at least one group Y in which Z is not H; and m is 1 to 100.

24. A diesel fuel composition according to claim 15 wherein the quaternizing agent is selected from dimethyl oxalate, methyl 2-nitrobenzoate and methyl salicylate.

25. An additive composition comprising a detergent additive which is not a quaternary ammonium salt or a Mannich reaction product; and a quaternary ammonium salt additive comprising the reaction product of nitrogen containing species having at least one tertiary amine group and an ester quaternizing agent; wherein the nitrogen containing species is selected from: (i) the reaction product of a hydrocarbyl-substituted acylating agent and a compound comprising at least one tertiary amine group and a primary amine, secondary amine or alcohol group; (ii) a Mannich reaction product comprising a tertiary amine group; and (iv) a polyalkylene substituted amine having at least one tertiary amine group.

Description

EXAMPLE 1

[0237] The performance of fuel compositions of the present invention in modern engines may be tested according to the CECF-98-08 DW 10 method.

[0238] The engine of the injector fouling test is the PSA DW10BTED4. In summary, the engine characteristics are: [0239] Design: Four cylinders in line, overhead camshaft, turbocharged with EGR [0240] Capacity: 1998 cm.sup.3 [0241] Combustion chamber: Four valves, bowl in piston, wall guided direct injection [0242] Power: 100 kW at 4000 rpm [0243] Torque: 320 Nm at 2000 rpm [0244] Injection system: Common rail with piezo electronically controlled 6-hole injectors. [0245] Max. pressure: 1600 bar (1.610.sup.8 Pa). Proprietary design by SIEMENS VDO [0246] Emissions control: Conforms with Euro IV limit values when combined with exhaust gas post-treatment system (DPF)

[0247] This engine was chosen as a design representative of the modern European high-speed direct injection diesel engine capable of conforming to present and future European emissions requirements. The common rail injection system uses a highly efficient nozzle design with rounded inlet edges and conical spray holes for optimal hydraulic flow. This type of nozzle, when combined with high fuel pressure has allowed advances to be achieved in combustion efficiency, reduced noise and reduced fuel consumption, but are sensitive to influences that can disturb the fuel flow, such as deposit formation in the spray holes. The presence of these deposits causes a significant loss of engine power and increased raw emissions.

[0248] The test is run with a future injector design representative of anticipated Euro V injector technology.

[0249] It is considered necessary to establish a reliable baseline of injector condition before beginning fouling tests, so a sixteen hour running-in schedule for the test injectors is specified, using non-fouling reference fuel.

[0250] Full details of the CEC F-98-08 test method can be obtained from the CEC. The coking cycle is summarised below. [0251] 1. A warm up cycle (12 minutes) according to the following regime:

TABLE-US-00001 Duration Engine Speed Torque Step (minutes) (rpm) (Nm) 1 2 idle <5 2 3 2000 50 3 4 3500 75 4 3 4000 100 [0252] 2. 8 hrs of engine operation consisting of 8 repeats of the following cycle

TABLE-US-00002 Boost Air Duration Engine Speed Load Torque After IC Step (minutes) (rpm) (%) (Nm) ( C.) 1 2 1750 (20) 62 45 2 7 3000 (60) 173 50 3 2 1750 (20) 62 45 4 7 3500 (80) 212 50 5 2 1750 (20) 62 45 6 10 4000 100 * 50 7 2 1250 (10) 20 43 8 7 3000 100 * 50 9 2 1250 (10) 20 43 10 10 2000 100 * 50 11 2 1250 (10) 20 43 12 7 4000 100 * 50 * for expected range see CEC method CEC-F-98-08 [0253] 3. Cool down to idle in 60 seconds and idle for 10 seconds [0254] 4. 4 hrs soak period

[0255] The standard CEC F-98-08 test method consists of 32 hours engine operation corresponding to 4 repeats of steps 1-3 above, and 3 repeats of step 4. ie 56 hours total test time excluding warm ups and cool downs.

EXAMPLE 2

[0256] The performance of fuel compositions of the present invention in older engine types may be assessed using a standard industry testCEC test method No. CEC F-23-A-01.

[0257] This test measures injector nozzle coking using a Peugeot XUD9 A/L Engine and provides a means of discriminating between fuels of different injector nozzle coking propensity. Nozzle coking is the result of carbon deposits forming between the injector needle and the needle seat. Deposition of the carbon deposit is due to exposure of the injector needle and seat to combustion gases, potentially causing undesirable variations in engine performance.

[0258] The Peugeot XUD9 A/L engine is a 4 cylinder indirect injection Diesel engine of 1.9 litre swept volume, obtained from Peugeot Citroen Motors specifically for the CEC PF023 method.

[0259] The test engine is fitted with cleaned injectors utilising unflatted injector needles. The airflow at various needle lift positions have been measured on a flow rig prior to test. The engine is operated for a period of 10 hours under cyclic conditions.

TABLE-US-00003 Stage Time (secs) Speed (rpm) Torque (Nm) 1 30 1200 30 10 2 2 60 3000 30 50 2 3 60 1300 30 35 2 4 120 1850 30 50 2

[0260] The propensity of the fuel to promote deposit formation on the fuel injectors is determined by measuring the injector nozzle airflow again at the end of test, and comparing these values to those before test. The results are expressed in terms of percentage airflow reduction at various needle lift positions for all nozzles. The average value of the airflow reduction at 0.1 mm needle lift of all four nozzles is deemed the level of injector coking for a given fuel.

EXAMPLE 3

[0261] Additive A1 is a 60% active ingredient solution (in aromatic solvent) of a polyisobutenyl succinimide obtained from the condensation reaction of a polyisobutenyl succinic anhydride (PIBSA) derived from polyisobutene of Mn approximately 1000 with a polyethylene polyamine mixture of average composition approximating to triethylene tetramine. The product was obtained by mixing the PIBSA and polyethylene polyamine at 50 C. under nitrogen and heating at 160 C. for 5 hours with removal of water.

EXAMPLE 4

[0262] Additive A2 is a 60% active ingredient solution (in aromatic solvent) of a polyisobutenyl succinimide obtained from the condensation reaction of a polyisobutenyl succinic anhydride derived from polyisobutene of Mn approximately 750 with a polyethylene polyamine mixture of average composition approximating to tetraethylene pentamine. The product was obtained by mixing the PIBSA and polyethylene polyamine at 50 C. under nitrogen and heating at 160 C. for 5 hours with removal of water.

EXAMPLE 5

[0263] Additive B1 was prepared as follows:

200 g of Dodecylsuccinic anhydride (0.75 mol) and 200 g toluene were added to a vessel and stirred under nitrogen. The temperature was raised to 50 C. and hydrazine monohydrate (112.8 g, 2.25 mol) added dropwise. Once addition was complete, the mixture was heated to reflux for 5 hours. Toluene was removed at 40 C. until no more bubbling was observed and then the product was held for 4 hours under vacuum at 180 C.

EXAMPLE 6

[0264] Additive C1 was prepared as follows:

50 g of rape seed oil fatty acid (ROFA) (173 mmoles) and 22.4 g Di-n-butylamine (173 mmoles) were mixed with stirring. An exotherm was observed. FTIR analysis of the reaction product indicated that a salt had formed: there was a reduction in the strong carboxylic acid peak at 1710 cm.sup.1 compared to the starting acid, and carboxylate antisymmetric and symmetric stretches at 1553 and 1399 cm.sup.1 appeared as well a broad range of peaks 2300-2600 cm.sup.1 assignable to ammonium species.

EXAMPLE 7

[0265] Additive D1 was prepared as follows:

A reactor was charged with 250.6 g (0.203 mol) PIBSA (made from 1000 MW PIB reacted with maleic anhydride), 251.1 g caromax 20 and 56.0 g toluene. The mixture was heated to 95 C. and 55.2 g (0.406 mol) aminoguanidine bicarbonate added slowly over 1 hour. The temperature was increased to 165 C. and held for 3 hours to remove water. Toluene was removed under vacuum.

EXAMPLE 8

[0266] Additive Q1, a quaternary ammonium salt additive was prepared as follows:

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 9

[0267] Additive Q2, a quaternary ammonium salt was prepared as follows:

A reactor was charged with 687.0 g (0.312 mol) PIBSI (made from 1000 MW PIB reacted with maleic anhydride, diluted in Caromax 20 then further reacted with DMAPA) and 205.99 g methanol. 35.6 ml (0.312 mol) styrene oxide and 18.64 g (0.312 mol) acetic acid were added. The mixture was heated to reflux for 5 hours. Methanol was removed under vacuum.

EXAMPLE 10

[0268] To a mixture of 1000 MW PIB-substituted phenol (300 g) in toluene (400 ml), at 50 C. was charged dimethylamine (40% solution in water, 26 g), followed by paraformaldehyde (7.2 g). The reaction was heated at 60 C. for 1 hour then to 120 C. for 4 hours with removal of water using Dean-Stark distillation. The product was cooled to below 50 C. and the toluene removed on a rotary evaporator to leave a pale orange clear viscous liquid (308.1 g).

EXAMPLE 11

[0269] Additive Q3, a quaternary ammonium salt was prepared as follows:

41.45 g (32.6 mMol) of the mannich reaction product prepared in example 10, methyl salicylate (5.00 g, 32.9 mMol) and 2-ethylhexanol (32.37 g, 41 wt % of total charge) were mixed with stirring under nitrogen and heated at 136 C. overnight. After 16 hours the reaction mixture was allowed to cool to below 80 C. and decanted, hot, to suitable storage and sample jars.

EXAMPLE 12

[0270] To a mixture of 1000 PIB-Chloride (300 g) in Xylenes (400 ml) at 50 C. was added Dimethylaminopropylamine (DMAPA, 70 g, 2.3 mole equivalents). The reaction was heated to reflux (140 C.) for 5 hours. The product was cooled to below 50 C. and Sodium Hydroxide (50% m/m, 50 g) was added and mixed for 1 hour at 50 C. The mixture was transferred to a separating funnel with water (200 ml) and the organics separated after two days. The organics were washed with further water (2200 ml), dried over anhydrous MgSO.sub.4 and filtered. The Xylenes were removed on a rotary evaporator to leave a dark brown/black viscous liquid (305.6 g).

EXAMPLE 13

[0271] Additive Q4 a quaternary ammonium salt was prepared as follows:

40.50 g (26 mMol) of the polyisobutylamine prepared in example 12, methyl salicylate (4.07 g, 26.7 mMol) and 2-ethylhexanol (29.54 g, 40 wt % of total charge) were mixed with stirring under nitrogen and heated at 140-141 C. overnight. After 16 hours the flask contents were allowed to cool to below 80 C. and decanted, hot, to suitable storage and sample jars.

EXAMPLE 14

[0272] Additive compositions F1 to F8 were prepared by mixing 50:50 ratios by weight of the crude products from examples 3-11 as identified table 1.

TABLE-US-00004 TABLE 1 Q1 Q2 Q3 Q4 A1 F1 A2 F2 F4 F7 F8 B1 F5 C1 F6 D1 F3

EXAMPLE 15

[0273] Fuel Compositions were prepared by adding 160 ppm by weight of the crude product from examples 3-12 in a common batch of RF06 basefuel.

[0274] Table 2 below shows the specification for RF06 base fuel.

TABLE-US-00005 TABLE 2 Limits Property Units Min Max Method Cetane Number 52.0 54.0 EN ISO 5165 Density at 15 C. kg/m.sup.3 833 837 EN ISO 3675 Distillation 50% v/v Point C. 245 95% v/v Point C. 345 350 FBP C. 370 Flash Point C. 55 EN 22719 Cold Filter C. 5 EN 116 Plugging Point Viscosity mm.sup.2/sec 2.3 3.3 EN ISO 3104 at 40 C. Polycyclic % m/m 3.0 6.0 IP 391 Aromatic Hydrocarbons Sulphur Content mg/kg 10 ASTM D 5453 Copper Corrosion 1 EN ISO 2160 Conradson Carbon % m/m 0.2 EN ISO 10370 Residue on 10% Dist. Residue Ash Content % m/m 0.01 EN ISO 6245 Water Content % m/m 0.02 EN ISO 12937 Neutralisation mg KOH/g 0.02 ASTM D 974 (Strong Acid) Number Oxidation mg/mL 0.025 EN ISO 12205 Stability HFRR (WSD1,4) m 400 CEC F-06-A-96 Fatty Acid Methyl prohibited Ester

EXAMPLE 16

[0275] Fuel compositions as detailed in table 3 were prepared by dosing quaternary ammonium salt additives of the present invention into an RFO6 base fuel meeting the specification given in table 2 (example 15) above. The effectiveness of these compositions in older engine types was assessed using the CEC test method No. CEC F-23-A-01, as described in example 2.

TABLE-US-00006 TABLE 3 Additive1 Additive2 XUD-9 (ppm of crude (ppm of crude % Average Flow Composition product) product) Loss None None 78.5 1 D1 (240) 69.0 2 D1 (80) Q1 (80) 16.8