FUEL COMPOSITIONS

Abstract

A method of cleaning up internal diesel injector deposits in a severely fouled engine, the method including combusting in the engine a diesel fuel composition having (a) a quaternary ammonium salt additive; and (b) one or more further nitrogen-containing detergents; in which the quaternary ammonium salt additive includes the quaternised reaction product of a hydrocarbyl substituted succinic acid derived acylating agent and a compound able to react with said acylating agent and which includes a tertiary amine group; in which each molecule of the hydrocarbyl substituted succinic acid derived acylating agent includes on average at least 1.2 succinic acid moieties.

Claims

1. A method of cleaning up internal diesel injector deposits in a severely fouled engine, the method comprising combusting in the engine a diesel fuel composition comprising (a) a quaternary ammonium salt additive; and (b) one or more further nitrogen-containing detergents; wherein the quaternary ammonium salt additive comprises the quaternised reaction product of a hydrocarbyl substituted succinic acid derived acylating agent and a compound able to react with said acylating agent and which includes a tertiary amine group; wherein each molecule of the hydrocarbyl substituted succinic acid derived acylating agent includes on average at least 1.2 succinic acid moieties.

2. The use of a combination of (a) a quatemary ammonium salt additive and (b) one or more further nitrogen-containing detergents to clean up internal diesel injector deposits in a severely fouled engine; wherein the quaternary ammonium salt additive comprises the quaternised reaction product of a hydrocarbyl substituted succinic acid derived acylating agent and a compound able to react with said acylating agent and which includes a tertiary amine group; wherein each molecule of the hydrocarbyl substituted succinic acid derived acylating agent includes on average at least 1.2 succinic acid moieties.

3. A diesel fuel composition comprising (a) a quaternary ammonium salt additive; and (b) one or more further nitrogen-containing detergents; wherein the quaternary ammonium salt additive comprises the quaternised reaction product of a hydrocarbyl substituted succinic acid derived acylating agent and a compound able to react with said acylating agent and which includes a tertiary amine group; wherein each molecule of the hydrocarbyl substituted succinic acid derived acylating agent includes on average at least 1.2 succinic acid moieties.

4. The method of claim 1, wherein the hydrocarbyl substituted succinic acid derived acylating agent is a polyisobutene-substituted succinic acid or succinic anhydride wherein the polyisobutene substituent has a number average molecular weight of between 450 to 2300.

5. The method of claim 1, wherein the compound able to react with the hydrocarbyl substituted succinic acid derived acylating agent and which includes a tertiary amine group comprises one or more compounds formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (I) or (II): ##STR00012## wherein R.sup.2 and R.sup.3 are the same or different alkyl, alkenyl, aryl, alkaryl or aralkyl groups having from 1 to 22 carbon atoms; X is an optionally substituted 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. The method of claim 5, wherein X is a propylene group.

7. The method of claim 1, wherein the quaternising agent used to prepare the quaternary ammonium salt addive (a) is selected from the group consisting of an ester of a carboxylic acid, dialkyl sulfates, benzyl halides, hydrocarbyl substituted carbonates, hydrocarbyl substituted epoxides optionally in combination with an acid, alkyl halides, alkyl sulfonates, sultones, hydrocarbyl substituted phosphates, hydrocarbyl substituted borates, alkyl nitrites, alkyl nitrates, hydroxides, N-oxides, chloroacetic acid or salts thereof, or mixtures thereof.

8. The method of claim 1, wherein the quaternising agent used to prepare the quaternary ammonium salt addive (a) is selected from the group consisting of dialkyl sulfates, benzyl halides, hydrocarbyl substituted carbonates, hydrocarbyl susbsituted epoxides in combination with an acid, alkyl halides, alkyl sulfonates, sultones, hydrocarbyl substituted phosphates, hydrocarbyl substituted borates, N-oxides, chloroacetic acid or salts thereof, or mixtures thereof

9. The method of claim 1, wherein the quaternising agent used to prepare the quaternary ammonium salt addive (a) is a compound of formula (III): ##STR00013## wherein R is an optionally 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.

10. The method of claim 9, quaternizing agent is selected from dimethyl oxalate, methyl 2-nitrobenzoate and methyl salicylate.

11. The method of claim 9, quatemizing agent is an ester of a polycarboxylic acid.

12. The method of claim 1, wherein component (b) comprises (i) the product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol.

13. The method of claim 12, wherein component (b) comprises (i) the product of a Mannich reaction between: (x) formaldehyde; (y) a polyethylene polyamine; and (z) a para-substituted monoalkyl phenol.

14. The method of claim 1, wherein component (b) comprises (ii) the reaction product of a carboxylic acid-derived acylating agent and an amine.

15. The method of claim 14, wherein component (ii) comprises the reaction product of a polyisobutene-substituted succinic acid or succinic anhydride and a polyethylene polyamine selected from ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethylene-heptamine and mixtures and isomers thereof; wherein polyisobutene substituent has a number average molecular weight of between 500 and 2000.

16. The method of claim 1, wherein component (b) comprises (v) the reaction product of a hydrocarbyl-substituted dicarboxylic acid or anhydride and an amine compound or salt which product comprises at least one amino triazole group.

17. The method of claim 1, which provides a score in a DW10C clean up test in excess of 9.8, when introduced to an engine having a merit score of less than 8.

Description

EXAMPLE 1PREPARATION OF POLYISOBUTYLENESUCCINIC ANHYDRIDE (PIBSA)INVENTIVE

[0276] 700 g (0.7 mol) of polyisobutylene (M.sub.n 1000) was charged to a nitrogen flushed, jacketed reactor fitted with an overhead stirrer. The starting material was heated to 120 C. with stirring and nitrogen inerting was repeated. The reaction temperature was increased to 190 C. and maleic anhydride (82.4g, 0.84 mol, 1.2 eq) was charged over 1 hour. After maintaining a temperature of 190 C. for a further 1 hour, the temperature was increased to 200-208 C. and held in this range for 8 hours. Vacuum (<30 mbar) was then applied for 2.5 hrs, whilst maintaining the reaction temperature, which reduced the level of residual maleic anhydride to 0.05 wt %. The reaction mass was cooled to 80 C. then discharged from the reactor.

EXAMPLE 2PREPARATION OF PIBSACOMPARATIVE

[0277] The synthesis procedure was substantially identical to Example 1 and used the same grade of polyisobutylene (M.sub.n 1000). The charge of maleic anhydride was reduced (1 eq relative to polyisobutylene) and the reaction was held between 190-210 C. during the 8 hour heating period. Residual maleic anhydride was also measured as 0.05 wt %.

[0278] The properties of the reaction products of Examples 1 and 2 are summarised in Table 1.

TABLE-US-00001 TABLE 1 Molecular weight of PIB Acid value Unreacted PIB starting Example (mmolH+/g) (wt %) material (Mn) P value 1 1.89 18.5 1000 1.31 2 1.68 20.2 1000 1.17

EXAMPLE 3ADDITIVE Q1INVENTIVE

[0279] PIBSA prepared according to Example 1 was charged to a nitrogen flushed, jacketed reactor fitted with an overhead stirrer and heated to 120 C. 3-(dimethylamino)propylamine (DMAPA) (1eq relative to anhydride groups) was charged slowly, maintaining the reaction temperature between 120-130 C. After stirring at 120 C. for a further 1 hr, the reaction temperature was increased to 140 C. and held for 3 hrs with concurrent distillation of water. Methyl salicylate (2.1 eq relative to anhydride groups) was added in a single portion and heating was continued at 140 C. for 10 hours. The reaction mass was diluted with Aromatic 150 solvent to provide an overall solids content of 60 wt % prior to discharging from the reactor.

EXAMPLE 4ADDITIVE Q2COMPARATIVE

[0280] PIBSA prepared according to Example 2 was charged to a nitrogen flushed, jacketed reactor fitted with an overhead stirrer and heated to 90 C. 3-(dimethylamino)propylamine (DMAPA) (1eq relative to anhydride groups) was charged slowly, maintaining the reaction temperature between 90-100 C. After stirring at 90-100 C. for a further 1 hr, the reaction temperature was increased to 140 C. and held for 4 hrs with concurrent distillation of water. 2-ethylhexanol was added to adjust the solids content to 60 wt % then methyl salicylate (1 eq relative to anhydride groups) was added in a single portion and heating was continued at 140 C. for 15 hours. The reaction mass was cooled to 60 C. prior to discharging from the reactor.

EXAMPLE 5PREPARATION OF DMAPA POLYISOBUTYLENE SUCCINIMIDE PROPYLENE OXIDE/ACETIC ACID QUATERNARY AMMONIUM SALTINVENTIVE

[0281] PIBSA according to Example 1 was charged to a nitrogen flushed, jacketed reactor fitted with an overhead stirrer and heated to 120 C. 3-(dimethylamino)propylamine (DMAPA) (1eq relative to anhydride groups) was charged slowly, maintaining the reaction temperature between 120-130 C. After stirring at 120 C. for a further 1 hr, the reaction temperature was increased to 140 C. and held for 3 hrs with concurrent distillation of water. The reaction mass was cooled to room temperature, then acetic acid (0.71 eq relative to anhydride groups), 2-ethylhexanol (1.34 eq relative to anhydride groups) and water (0.81 eq relative to anhydride groups) were added. The reaction mass was heated to 75 C. and propylene oxide (2.39 eq relative to anhydride groups) was added over 3 hrs via a dropping funnel. Heating was continued for 4 hrs. The reaction mass was diluted with Aromatic 150 solvent to provide an overall solids content of 60 wt % prior to discharging from the reactor.

EXAMPLE 6PREPARATION OF DMAPA POLYISOBUTYLENE SUCCINIMIDE PROPYLENE OXIDE/ACETIC ACID QUATERNARY AMMONIUM SALTCOMPARATIVE

[0282] PIBSA according to Example 2 was used. Formation of the DMAPA succinimide and subsequent quaternization using propylene oxide/AcOH was carried out in identical manner to Example 5. Reactant charges were calculated relative to anhydride groups in the PIBSA starting material.

EXAMPLE 7PREPARATION OF DMAPA POLYISOBUTYLENE SUCCINAMIDE PROPYLENE OXIDE QUATERNARY AMMONIUM SALTINVENTIVE

[0283] PIBSA according to Example 1 (1 part) and Caromax 20 (1 part) were charged to a nitrogen flushed, jacketed reactor fitted with an overhead stirrer and heated to 80 C. to ensure proper mixing, then cooled to room temperature. 3-(dimethylamino)propylamine (DMAPA) (1eq relative to anhydride groups in the PIBSA starting material) was added over 3 hrs, maintaining the reaction temperature below 40 C. The reaction mass was stirred for a further 4 hrs, then propylene oxide (2 eq relative to anhydride groups) was added over 3 hrs, then the reaction mass stirred at room temperature for 4 hrs. After nitrogen sparging to remove residual propylene oxide, the reaction mass was discharged from the reactor.

EXAMPLE 8PREPARATION OF DMAPA POLYISOBUTYLENE SUCCINAMIDE PROPYLENE OXIDE QUATERNARY AMMONIUM SALTCOMPARATIVE

[0284] PIBSA according to Example 2 was used. Formation of the DMAPA succinamide and subsequent quaternization using propylene oxide was carried out in identical manner to Example 7. Reactant charges were calculated relative to anhydride groups.

EXAMPLE 9ADDITIVE A1

[0285] Additive A1, a Mannich reaction product additive of the prior art was prepared as follows:

[0286] A 1 L reactor was charged with dodecylphenol (170.6 g, 0.65 mol), ethylenediamine (30.1 g, 0.5 and Caromax 20 (123.9g). The mixture was heated to 95 C. and formaldehyde solution, 37 wt % (73.8g, 0.9 mol) charged over 1 hour. The temperature was increased to 125 C. for 3 hours and water removed. In this example the molar ratio of aldehyde (a): amine (b): phenol (c) was approximately 1.8:1:1.3.

EXAMPLE 10ADDITIVE A2

[0287] Additive A2 is a 60 wt % 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 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 11

[0288] Fuel compositions were prepared by adding additives Q1, Q2, A1 and A2 to diesel fuel.

[0289] The diesel fuel complied with the RF06 base fuel, the details of which are given in table 1 below.

TABLE-US-00002 TABLE 1 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 Plugging C. 5 EN 116 Point Viscosity at 40 C. mm.sup.2/sec 2.3 3.3 EN ISO 3104 Polycyclic Aromatic % m/m 3.0 6.0 IP 391 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 (Strong mg KOH/g 0.02 ASTM D 974 Acid) Number Oxidation Stability mg/mL 0.025 EN ISO 12205 HERR (WSD1,4) m 400 CEC F-06-A-96 Fatty Acid Methyl prohib- Ester ited

EXAMPLE 12

[0290] The ability of additives of the invention to remove Internal Diesel Injector Deposits (IDIDs) may be measured according to the test method CEC F-110-16, available from the Co-ordinating European Council. The test uses the PSA DW10C engine.

[0291] The engine characteristics as follows:

TABLE-US-00003 Design: Four cylinders in line, overhead camshaft, variable geometry turbocharger with EGR Capacity: 1997 cm.sup.3 Combustion Four valves, bowl in piston, direct injection chamber: Power: 120 KW @: 3750 rpm Torque: 340 Nm @ 2000 rpm Injection system: Common rail with solenoid type injectors Delphi Injection System Emissions control: Conformis to Euro V limit values when combined with exhaust gas post-treatment system.

[0292] The test fuel (RF06) is dosed with 0.5 mg/kg Na in the form of Sodium Naphthenate+10 mg/kg Dodecyl Succinic Acid (DDSA).

[0293] The test procedure consists of main run cycles followed by soak periods, before cold starts are carried out.

[0294] The main running cycle consist of two speed and load set points, repeated for 6 hrs, as seen below.

TABLE-US-00004 Step Speed (rpm) Torque (N .Math. m) Duration (s) 1 3750 280 1470 1 - Ramp .fwdarw.2 30 2 1000 10 270 2 - Ramp .fwdarw.1 30
The ramp times of 30 seconds are included in the duration of each step.

[0295] During the main run, parameters including, Throttle pedal position, ECU fault codes, Injector balance coefficient and Engine stalls are observed and recorded.

[0296] The engine is then left to soak at ambient temperature for 8 hrs.

[0297] After the soak period the engine is re-started. The starter is operated for 5 seconds; if the engine fails to start the engine is left for 60 seconds before a further attempt. A maximum of 5 attempts are allowed.

[0298] If the engine starts the engine is allowed to idle for 5 minutes. Individual exhaust temperatures are monitored and the maximum Temperature Delta is recorded. An increased variation in Cylinder-to-Cylinder exhaust temperatures is a good indication that injectors are suffering from IDID. Causing them to either open slowly or stay open to long. An example below of all exhaust temperatures with <30 C. deviation, indicating no sticking caused by IDID.

[0299] The complete test comprises of 6 Cold Starts, although the Zero hour Cold Start does not form part of the Merit Rating and 5 6 hr Main run cycles, giving a total of 30 hrs engine running time. The recorded data is inputted into the Merit Rating Chart. This allows a Rating to be produced for the test. Maximum rating of 10 shows no issues with the running or operability of the engine for the duration of the test.

[0300] An example below:

TABLE-US-00005 Cold start 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 25 25 25 indicates data missing or illegible when filed

[0301] The propensity of the test fuel to cause injector deposits (IDID) is evaluated through the following criteria:

Cold Start Parameters:

[0302] 1. Number of failed starts. [0303] 2. Exhaust temperature deviation from standard value for cylinders 1 to 4

Main Run Parameters

[0304] 1. Number of engine stalls [0305] 2. Number of IDID related ECU faults generated during main run [0306] 3. Pedal position drift on low speed phases [0307] 4. Injector balancing

[0308] Note: 1st Cold start (#0) is run with Flush fuel and is not rated

[0309] The rating can be summarized as follows:

[0310] 1/Cold Start (for start #1 to #5):

Startability Rating:

[0311] 1st start: merit=5/each fail brings a 1 merit discount.

Maximum Exhaust Ports Temperature Deviation Rating:

[00003]$\mathrm{merit}=5\mathrm{if}T<30C./2\mathrm{if}30C.<T<50C./0\mathrm{if}T>50C.$

[0312] Cold Start Rating range: 0->10 for each Cold Start (5 Cold Starts rated in total)

[0313] 2/Main Run (for run #1 to #5):

Operability Rating:

[0314] merit=5 if no stall and no IDID related ECU Fault, each IDID related ECU fault brings a 1 merit discount (after 5th ECU Fault Reset->Next cold start). [0315] merit=0 if stall (Then->Next Cold Start).

Maximum Pedal Position:

[00004]$\mathrm{merit}=5\mathrm{if}P<25\%/2\mathrm{if}25\%<P<40\%/0\mathrm{if}P>40\%$

Maximum Injector Balancing Factror deduction:

[00005]$\mathrm{merit}=5\mathrm{if}\mathrm{IB}<20\mathrm{rpm}/2\mathrm{if}30\mathrm{rpm}<\mathrm{IB}<20\mathrm{rpm}/0\mathrm{if}\mathrm{IB}>30\mathrm{rpm}$

Main Run Rating Range: 0->5 for each Main Run (5 in total)

[0316] Maximum global rating value: 75 (ie: 5 10+55).

[00006]$\mathrm{Global}\mathrm{rating}=10\left(\mathrm{Cold}\mathrm{Start}+\mathrm{Main}\mathrm{Run}\mathrm{Rating}\mathrm{values}\right)/75$

Resulting in 0 to 10 Merit Scale

EXAMPLE 13

[0317] The ability of additives of the invention to clean up IDIDs was assessed according to a modification of the DW10C test described in example 12.

[0318] The In-House Clean-Up Method developed starts by running the engine using reference diesel (RF06) dosed with 0.5 mg/kg Na+10 mg/Kg DDSA until an exhaust temperature Delta of >50 C. is observed on the Cold Start. This has repeatedly been seen on the 3.sup.rd Cold Start which follows the second main run, 12 hrs total engine run time.

[0319] Once the increased Exhaust temperature Delta is observed, the engine fuel supply is swapped to reference diesel, dosed with 0.5 mg/kg Na (as sodium naphthenate)+10 mg/kg DDSA+the Candidate sample. The fuel is flushed through to the engine and allowed to commence with the next Main run.

[0320] The ability of the Candidate additive to prevent any further increase in deposits or to remove the deposits can then be determined as the test continues.

EXAMPLE 14

[0321] Diesel fuel compositions were prepared comprising the additives indicated in the table below and tested according to the procedure detailed in examples 6 and 7.

[0322] The results show that the additive combination according to the invention provides excellent performance in a highly fouled engine.

TABLE-US-00006 Additive Additive Additive Additive Dirty Clean Q1 (ppm Q2 (ppm A1 (ppm A2 (ppm up up active) active) active) active) rating rating 24 13 30 6.7 7.6 24 13 30 6.93 10 24 30 7.87 10