USE AND METHOD

Abstract

The use of nitrogen-containing compounds as additives in a diesel fuel composition to reduce the impact of deposits in the post combustion system of a diesel engine when combusting said diesel fuel composition. The nitrogen-containing compounds comprise at least 4% by mass of nitrogen atoms and in some embodiments fewer than five NH bonds.

Claims

1. Use of one or more nitrogen-containing compounds as an additive in a diesel fuel composition to reduce the impact of deposits in the post combustion system of a diesel engine when combusting said diesel fuel composition, wherein the nitrogen-containing compounds comprise at least 4% by mass of nitrogen atoms.

2. A method of reducing the impact of deposits in the post combustion system of a diesel engine, the method comprising combusting in the engine a diesel fuel composition comprising as an additive one or more nitrogen-containing compounds, wherein the nitrogen-containing compounds comprise at least 4% by mass of nitrogen atoms.

3. The method according to claim 2 which reduces the formation of deposits in the post combustion system of a diesel engine.

4. The method according to claim 2, wherein the nitrogen-containing compound is the reaction product of a) a hydrocarbyl substituted reagent and b) a nitrogen-containing reagent.

5. The method according to claim 2, wherein the nitrogen-containing compound has the formula (I):
A-L-R.sup.1 (I) wherein: A is a nitrogen-containing group; L is either a bond or a linker group; and R.sup.1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000.

6. The method according to claim 5, wherein the nitrogen-containing group A is a nitrogen-containing heterocycle and is selected from an optionally substituted piperazine, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, quinazoline, a five-membered heterocyclic ring such as pyrazole or imidazole or a benzo-fused five-membered heterocyclic ring such as benzimidazole.

7. The method according to claim 5, wherein the A group is a non-cyclic nitrogen-containing group having the formula (II): ##STR00046## wherein n is from 1 to 10.

8. The method according to claim 5, wherein L is a bond, an amide, a succinimide, a succinic acid or an amide of a succinic acid.

9. The method according to claim 2, wherein the nitrogen-containing compound is the reaction product of: a) a hydrocarbyl substituted carboxylic acid acylating agent; and b) a nitrogen-containing reagent.

10. The method according to claim 9, wherein component a) has the formula (aI): ##STR00047## wherein R.sup.1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000.

11. The method according to claim 9, wherein component b) is either: selected from an optionally substituted benzotriazole, amino-benzotriazole, indazole, amino-indazole, triazole, amino-triazole, tetrazole or amino-tetrazole; or has the formula (bI): ##STR00048## wherein n is from 1 to 10.

12. The method according to claim 2, wherein the nitrogen-containing compound has the formula (III): ##STR00049## wherein: A is the nitrogen-containing group; R.sup.1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; and R.sup.2 is OH, NH.sub.2, OR.sup.4, NHR.sup.4 or NR.sup.4R.sup.5, wherein R.sup.4 and R.sup.5 are independently selected from optionally substituted C1-6 alkyl or alkenyl groups, or is a bond to A.

13. The method according to claim 12, wherein the nitrogen-containing compound has the formula (IV), (IVb) or (IVc), or a mixture thereof: ##STR00050## wherein R.sup.1 and R.sup.2 are as defined in claim 12.

14. The method according to claim 12, wherein the nitrogen-containing compound has the formula (V): ##STR00051## wherein n is from 1 to 3, or a mixture thereof; and wherein R.sup.1 is as defined in claim 12.

15. The method according to claim 2, wherein the nitrogen-containing compound is the reaction product of: a) an amine or polyamine comprising a hydrocarbyl group; b) a nitrogen-containing reagent; and c) an aldehyde.

16. The method according to claim 15, wherein: a) is an alkylamine having the formula NHR.sup.7R.sup.8 wherein R.sup.7 and R.sup.8 are each independently selected from H, optionally substituted C1-20 alkyl groups or optionally substituted C1-20 alkenyl groups; b) is a nitrogen-containing reagent selected from an optionally substituted triazole, tetrazole, indole, indazole or benzotriazole, and. c) is formaldehyde or a source of formaldehyde.

17. The method according to claim 2, wherein the nitrogen-containing compound has the formula (VI): ##STR00052## wherein: R.sup.1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; W, X, Y and Z are each independently selected from CH, C, N, NH, S and SH; and wherein the compound optionally comprises a cycloalkyl or aryl ring linking Y and Z.

18. The method according to claim 17, wherein the nitrogen-containing compound has the formula (IX): ##STR00053## wherein: R.sup.1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; W and X are each independently selected from C and N; and each R.sup.6 is independently selected from H, C1-6 alkyl or C1-6 alkenyl.

19. The method according to claim 18, wherein R.sup.1 is CH.sub.2NR.sup.7R.sup.8 and R.sup.7 and R.sup.8 are each independently selected from H, optionally substituted C1-20 alkyl groups or optionally substituted C1-20 alkenyl groups.

20. The method according to claim 2, wherein the nitrogen-containing compound comprises fewer than five NH bonds.

21. The method according to claim 2, wherein the diesel fuel composition comprises from 50 to 2000 ppm of the one or more nitrogen-containing compounds.

22. The method according to claim 2, wherein the diesel fuel composition comprises from 50 to 350 ppm of the one or more nitrogen-containing compounds.

23. The method according to claim 2 which reduces deposits in the post combustion system of a diesel engine having a pressure in excess of 1350 bar.

24. The method according to claim 2 which reduces the formation of deposits on the turbocharger of the post combustion system.

25. The method according to claim 2 which reduces the formation of deposits on the diesel oxidation catalyst of the post combustion system.

26. The method according to claim 2 which reduces the formation of deposits on the diesel particulate filter of the post combustion system.

27. The method according to claim 2 which reduces the formation of deposits on the selective catalytic reduction unit of the post combustion system.

28. The method according to claim 2 which reduces the formation of deposits on the ammonia oxidation catalyst of the post combustion system.

29. The method according to claim 2 which reduces the formation of deposits on sensors within the post combustion system.

30. The method according to claim 2 which reduces the formation of deposits in one or more components of the post combustion system by at least 5%.

31. The method according to claim 2 which allows a reduction in temperature of exhaust gas used to regenerate a diesel particulate filter of the post combustion system.

32. The method according to claim 2 which allows a reduction in the frequency of diesel particulate filter regeneration in said diesel engine.

33. The method according to claim 2 wherein the diesel fuel composition comprises one or more nitrogen-containing detergents.

34. The method according to claim 33 wherein the one or more nitrogen-containing detergents are selected from: (i) a quaternary ammonium salt additive; (ii) the product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; and (iii) the reaction product of a carboxylic acid-derived acylating agent and an amine.

35. The method according to claim 2, wherein the diesel engine is an off-road engine, for example a marine, rail or stationary engine.

36. The method according to claim 2 which provides one or more benefits selected from: an increase in power generation; an increase in torque; an increase in fuel economy; a reduction in emissions; a reduction in combustion chamber deposits; an acceleration improvement; driveability improvements; a reduction in cold start issues; lower soot formation; mitigation of lubricant degradation and/or performance loss; a reduction in diesel exhaust fluid and consumption e.g. urea consumption; reduction in wear on all post combustion components; increased longevity of exhaust components; an increase in the maintenance period for the engine and/or post combustion components; and the protection of intake components downstream of the EGR, for example swirl flaps, throttles and the intake manifold.

37. A fuel additive composition comprising one or more nitrogen-containing compound and a detergent additive, wherein the nitrogen-containing compounds comprise at least 4% by mass of nitrogen atoms.

38. A diesel fuel composition comprising one or more nitrogen-containing compound and a detergent additive, wherein the nitrogen-containing compounds comprise at least 4% by mass of nitrogen atoms.

39. The diesel fuel composition according to claim 38, comprising one or more further additives selected from antioxidants, dispersants, detergents, metal deactivating compounds, wax anti-settling agents, cold flow improvers, cetane improvers, dehazers, stabilisers, demulsifiers, antifoams, corrosion inhibitors, lubricity improvers, dyes, markers, combustion improvers, metal deactivators, odour masks, drag reducers and conductivity improvers.

40. The fuel additive composition according to claim 37, wherein the detergent additive is: a reaction product of a carboxylic acid-derived acylating agent and an amine the detergent additive is the reaction product of tetraethylene pentamine (TEPA) and a PIBSA having a PIB number average molecular weight (Mn) of from 300 to 2800; or a quaternary ammonium salt formed by reacting methyl salicylate or dimethyl oxalate with the reaction product of dimethylaminopropylamine and a polyisobutylene-substituted succinic anhydride having a PIB number average molecular weight (Mn) of 700 to 1300.

Description

EXAMPLES

[0474] Example nitrogen-containing compounds for use as additives in a diesel fuel composition according to the invention were prepared as follows.

Example 1PIB.SUB.260.SA 5-amino-[1H]-tetrazole Reaction Product

Major Components:

##STR00036##

[0475] The nitrogen-containing compound of Example 1 was prepared as follows. Thermal reaction of a high-reactive grade of 260 number average highly reactive (HR) poly(isobutene) (PIB.sub.260) with maleic anhydride (MA) provided a sample of poly(isobutene)succinic anhydride (PIB.sub.260SA). The PIB.sub.260SA was characterised in part by titration against lithium methoxide and found to have an activity of 2.38 mmol.Math.g.sup.1.

[0476] A reactor was charged with a sample (135.01 g, 321.3 mmol) of the PIB.sub.260SA and Caromax20 solvent (162.3 g) and heated to 90 C. 5-amino-[1H]-tetrazole monohydrate (33.10 g, 321.1 mmol) was added and the flask contents were heated to above 100 C. for an hour. Following this the temperature was increased to achieve an internal temperature of 170 C., facilitating the formation of the amide. progress of the reaction was monitored using ATR-FTIR.

[0477] Nitrogen contents for three essentially identically prepared samples were determined by analysis using a Leco Flash 1112 series analyser and found to range from 6.45 to 6.53 wt %. The theoretical nitrogen content of the target compound is from 15.1 to 17.2 wt %.

Example 2C.SUB.16./C.SUB.18 .ASA 5-amino-[1H]-tetrazole Reaction Product

Major Components:

##STR00037##

wherein the R.sup.3 groups sum to C.sub.13H.sub.28 or C.sub.15H.sub.32 or a mixture thereof.

[0478] The nitrogen-containing compound of Example 2 was prepared as follows. The activity of a sample of Pentasize 68 (a commercially available C16 to C18 alkenyl succinic anhydride (ASA)) was determined by lithium methoxide titration to be 2.97 mmol.Math.g.sup.1. A reaction flask was charged with 16.86 g (50 mmol activity) in a high aromatic solvent Innosol PP (20.256 g). 5-amino-[1H]-tetrazole monohydrate (5.164 g 50 mmol) was added and stirred to form a dispersion.

[0479] The dispersion was heated using a thermostat-controlled oil bath to an eventual internal temperature of 170 C. Progress of the reaction was monitored at intervals using ATR-FTIR spectroscopy. The product contained approximately 50 wt % of the C16/C18 ASA 5-amino-[1H]-tetrazole reaction product. The theoretical nitrogen content of the target compound is from 16.1 to 17.8 wt %.

Example 3Imide from Reaction of C16/C18 ASA with Tetraethylenepentamine (TEPA)

Major Components:

##STR00038##

wherein the R.sup.3 groups sum to C.sub.13H.sub.28 or C.sub.15H.sub.32 or a mixture thereof.

[0480] The nitrogen-containing compound of Example 3 was prepared as follows. The activity of a sample of Pentasize 68 (a commercially available C16 to C18 alkenyl succinic anhydride (ASA)) was determined by lithium methoxide titration to be 2.97 mmol.Math.g.sup.1. A reaction flask was charged with 150.02 g (446 mmol activity) of Pentasize 68 and 2-ethylhexan-1-ol solvent (234.09 g). A pressure-equalised dropping funnel was charged with TEPA (84.40 gg, 446 mmol, 1.0 moles per anhydride group). The flask contents were warmed in an oil bath controlled by a thermostat set at 70 C. The oil bath set point was increased to 175 C. and the reactor contents allowed to warm.

[0481] Reaction progress was monitored at intervals using ATR-FTIR spectroscopy. The product comprised 49.88 wt % of the imide products. The theoretical nitrogen content of the target compound is from 13.0 to 13.7 wt %.

Example 4Mannich Reaction Product of Diethylamine, Formaldehyde and Benzotriazole

Major Components:

##STR00039##

[0482] The nitrogen-containing compound of Example 4 was prepared as follows. Following the method of Katritzky et al J Chem Soc Perkin Trans 1987, 2673, diethylamine (21.945 g, 301 mmol) was added to methanol (100 cm3). This mixture was cooled back to 3 C. and 1H benzotriazole (35.739 g, 301 mmol) was added. Aqueous formaldehyde (nominally 37 wt %, 24.324 g, 300 mmol, 1.0 equivalents) was added to the reactor over 10 minutes and the reaction mixture was stirred for 50 minutes before being allowed to warm to ambient temperature whilst stirring overnight. Methanol was removed at the rotary evaporator and 58.441 g (expected 61.33) of a slightly viscous yellow oil were recovered.

[0483] The product obtained was confirmed by comparison of the ATR-FTIR spectra with the literature. .sup.1H NMR was consistent with the Katritzky reference but indicated a ratio of 1-isomer to 2-isomer of 3.71. The product was found by a Thermoflash elemental analyser to contain 62.24 wt % C, 7.55 wt % H and 27.09 wt % N. The theoretical nitrogen content of the target compound is 27.4 wt %.

[0484] A solution at 63.5 wt % of the target compound in 2-ethylhexanol gave clean and bright diesel fuel solutions at up to 5 wt % active material.

Example 5Two Phase Mannich Reaction Product of Diethylamine, Formaldehyde and Benzotriazole

Major Components:

##STR00040##

[0485] A reaction flask was charged with benzotriazole powder (60.0 g, 0.504 mol) and solvent 150 (102.8 g). The slurry was warmed to 30 C. before diethylamine (15.1 g) was added. Aqueous formaldehyde (36.8 g of a 37 wt % formaldehyde solution) was then added over a period of 25 minutes, keeping the temperature at 40-47 C. After two hours stirring at 40 C. the reactor contained two liquid phases which were heated to 70 C. before transfer to a separating funnel. The recovered aqueous phase comprised 27.4 g of material. Additional water, accompanied by some organics, was removed by vacuum distillation at 70 C., 25 mBar leaving a clear solution of organic material.

[0486] The product structure was confirmed by FTIR. Theoretical N content of this product is 13.7 wt %.

Example 6Two Phase Mannich Reaction Product of Benzotriazole, Formaldehyde and bis(2-ethylhexyl)amine

Major Components:

##STR00041##

[0487] The nitrogen-containing compound of Example 6 was prepared as follows. A reaction flask was charged with benzotriazole powder (50.1 g, 0.421 mole) and 157 g of solvent 150. The slurry was warmed to approximately 30 C. before adding bis(2-ethylhexyl)amine (101.7 g) over 20 minutes, followed by 34.1 g of 37 wt % active formaldehyde solution.

[0488] The reaction mixture was heated to 80 C. and transferred to a separating funnel and the organic layer was separated. Distillation of water from the separated organic layer resulted in a clear organic phase giving an FTIR spectrum similar to that of the product of Example 5.

[0489] The theoretical nitrogen content of the target compound is 15.0 wt %.

Example 7Two Phase Mannich Reaction Product of 1,2,4-triazole, Formaldehyde and di-n-butylamine

Major Component:

##STR00042##

[0490] The nitrogen-containing compound of Example 7 was prepared as follows. 1,2,4-triazole (40.4 g, 0.585 mole) and 133.6 g of solvent 150 were charged to a reaction flask, followed by the di-n-butylamine (75.6 g). After further warming (39 C.), addition of the aqueous formaldehyde (47.4 g of 37 wt % solution) commenced.

[0491] The organic layer was separated from the reaction mixture and dried by vacuum distillation to yield the 249.6 g of the product solution. Theoretical N content of the product mixture (including solvent) is 13.3 wt %, by analysis the concentrate contained 13.0 wt % N, 60.8 wt % C and 8.7 wt % H.

[0492] The theoretical nitrogen content of the target compound is 26.6 wt %.

Example 8: Benzotriazole-Formaldehyde-Dibutylamine

Major Components:

##STR00043##

[0493] In a 500 ml round bottomed flask, charged benzotriazole (60.1 g, 0.505 moles, 1.0 eq) and A150 solvent (131.5 g) and heated to 30 C., forming a white slurry. Added dibutylamine (65.3 g, 1 eq, 0.505 moles) via dropping funnel over 25 mins. With the mixture in the flask at 31 C., formalin addition (37% w/w, 41.0 g, 0.505 moles, 1.0 eq) started and carried out of a period of 15-20 mins. A milky white liquid forms immediately after addition, with the contents two phases. The temperature of the reactor contents were then adjusted to 45-50 C. and held at this temperature for 5 hrs. The reaction mixture was allowed to cool overnight. To separate the reaction mixture, it was heated to 70 C. The separation is clear, and the lower now hazy aqueous layer was ran off. Collected 30.9 g, theoretical water in the reaction is 34.9 g. Heated the organic phase to 75 C. and applied vacuum to 20 mbar.

[0494] Isolated 254.9 g of clear bright yellow liquid (as 50% actives solution).

[0495] The theoretical nitrogen content of the target compound is 21.5 wt %.

Example 9: Benzotriazole-Formaldehyde-Armeen 2C (Dicocoalkylamine)

Major Components:

##STR00044##

[0496] In a 500 ml round bottomed flask, charged benzotriazole (26.0 g, 0.218 moles, 1.0 eq) and A150 solvent (116.0 g) and heated to 90 C. The flask was charged the Armeen 2C (87.4 g, 0.218 moles, 1 eq [equivalent weight is 401 g/mol]) (dicocoalkylamine wherein cocoalkyl=mixture of C6-18 alkyl). Formalin (37% w/w, 0.218 moles, 1.0 eq) was then added over 5 mins and then the reaction mixture was stirred at 90 C. for 2.5 hrs. The temperature in the reaction flask was increased over a period of 3 hrs to 119 C. and water removed via Dean and Stark trap. When no further aqueous phase was being collected and the product was clear and bright the temperature was cooled to ambient. Collected 222.5 g of clear bright amber liquid (as 50% actives solution).

Example 10: 1,2,4-triazole-formaldehyde-bis(2-ethylhexyl)amine

Major Component:

##STR00045##

[0497] Formalin (159.6 g of 26.6% active formaldehyde, 1.9447 mol, 0.995 eqs) and 1,2,4-triazole (156.0 g, 1.9545 mols, 1.0 equiv) are charged and heated to 60 C. Bis-(2-ethylhexyl) amine (462.5 g, 1.9154 mols, 0.98 equivs) is added to the water mixture over 2.5 hrs at 60 C. and the batch is stirred for 1 hr to complete reaction. Water from the formalin solution and water of reaction is removed by vacuum distillation and 60-100 C. (100-200 mbar). Following water removal, residual volatiles and trace water are removed by stripping under increased vacuum and the product (615.4 g) is discharged via a filter as pale-yellow liquid.

[0498] The theoretical nitrogen content of the target compound is 17.4 wt %.

Engine Testing

[0499] Engine testing was carried out as described below to assess the performance of the nitrogen-containing additives of the present invention in the reduction of deposits in the post combustion system of diesel engines.

Engine Details

[0500] A Euro 6 compliant 2.0 litre, HSDI engine was connected to a test automation system and test bed fitted with an engine dynamometer. The engine was controlled by an ECU supplied by the engine manufacturer. The engine had had over 1100 h of use prior to the first test. The engine oil was changed prior to performing the first test.

Modifications/Test Setup

[0501] 1. No SCR Catalyst or associated components were present in the exhaust system. [0502] 2. High pressure EGR cooler is artificially controlled to 40 C. for the duration of the test.

[0503] The base fuel was an RF-06-03 diesel fuel (Haltermann Carless, UK) having the following specification:

TABLE-US-00001 Feature Units Results Minimum Maximum Method Density 15 C. kg/m.sup.2 836.0 833.0 837.0 ASTM D4052 Marker (Red) Pass VISUAL Cetane Number 53.9 52.0 54.0 ASTM D613 I.B.Pt C. 214.3 ASTM D86 10% v/v Recovered at C. 232.0 ASTM D86 50% v/v Recovered at C. 275.5 245.0 ASTM D86 90% v/v Recovered at C. 330.2 ASTM D86 95% v/v Recovered at C. 348.0 345.0 350.0 ASTM D86 F.B.Pt. C. 356.2 370.0 ASTM D86 Aromatics by FIA %(V/V) 19.8 Corrected for ASTM D1319 Olefins by FIA %(V/V) 5.5 Flash Point, Pensky Closed C. 92.0 55.0 ASTM D93 Sulphur Content mg/kg <3.0 10.0 ASTM D5453 Viscosity al 40 C. mm2/s 3.062 2.300 3.300 ASTM D445 Cloud Point C. 18 ASTM D2500 CFPP C. 20 15 EN 116 Lubricity (WSD 1, 4) at 60 C. m 180 400 ISO 12156-1 Carbon Residue (on 10% Dist. Res) %(m/m) <0.10 0.20 ASTM D4530 Ash %(m/m) <0.001 0.010 ASTM D482 FAME Content: None Detected Pass EN 14078 Polycyclic Aromatic Hydrocarbons %(m/m) 5.8 3.0 6.0 EN 12916 Total Aromatic Hydrocarbons %(m/m) 22.2 EN 12916 Water Content mg/kg 50 200 IP 438 Water & Sediment %(V/V) <0.010 ASTM D2709 Strong Acid Number mg 0 KOH/g 0.02 ASTM D974 Oxidation Stability mg <0.1 per 2.5 ASTM D2274 100 ml Copper Corrosion, 3 hrs at 100 C. 18 ASTM D130 Oxygen Content %(m/m) <0.04 ELEMENTAL Elemental Analysis Carbon Content %(m/m) 86.89 ASTM D5291 ASTM D5291 Hydrogen Content %(m/m) 13.11 ASTM D5291 ASTM D5291 Carbon Weight Fraction 0.6689 CALCULATION Calculation C/H Mass Ratio 6.63 CALCULATION Calculation Atomic H/C Ratio 1.7979 CALCULATION Calculation Atomic O/C Ratio <0.0003 CALCULATION Calculation Gross Heat of Combustion MJ/kg 45.72 IP 12 IP 12 Net Heat of Combustion MJ/kg 42.94 IP 12 IP 12 Net Heat of Combustion btu/lb 18460 CALCULATION Calculation

Test Additives, Treat Rate:

[0504] The example nitrogen-containing compounds were dosed at 100 mg/kg into the base diesel fuel described above. The nitrogen-containing compound of Example 9 was dosed into the base fuel to provide test fuel A.

Method of Soot Deposition Measurement (DPF & EGR Soot Weight)

[0505] The quantity of soot deposited in the DPF was established by weighing both components before and after each test.

[0506] Prior to the initial weighing, the DPF is passively regenerated on the test bed to remove any residual soot. Once the regeneration is complete, the DPF is placed into an oven, pre-heated to 185 C., affixed to a set of scales. The weight measurement was taken as an average over 15 minutes, once the scales had stabilised. This weighing process is repeated at the end of the test. The variance between the weight measured before and after the test represents the change in mass due to soot deposition.

Test Procedure

[0507] [D] EGR Cleaned and weighed [0508] [D] DPF+Slave EGR Installation [0509] Engine Start+Warm-Up [0510] Passive DPF Regeneration by varying the engine speed and load until the regeneration is complete. The differential pressure across the is used to monitor the regeneration progress. [0511] Engine Stop [0512] Change to test fuel [0513] [C] DPF+Slave EGR Removal [0514] [C] DPF Start-of-Test (SOT) Weighing [0515] [C] DPF+[C] EGR Installation [0516] Engine Start+Warm-Up [0517] 8-Hour Steady-State Test Cycle [0518] 1200 RPM [0519] 60 Nm [0520] Engine Stop [0521] [D] DPF Removal and End-of-Test (EOT) Weighing [0522] [D] EGR Removal and EGR End of Test Weighing [0523] [C] indicates a clean component [0524] [D] indicates a fouled component

Results

TABLE-US-00002 Treat rate DPF Soot Test fuel Additive (mg/kg) Weight [g] Base fuel 36.35 A Example 9 100 35.87

[0525] These results demonstrate that the use of the nitrogen-containing compounds described herein as additives in a diesel fuel composition may provide a significant reduction in deposits in the post combustion system of a diesel engine combusting said fuel, specifically a reduction in the soot deposited on the diesel particulate filter of the post combustion system.