NO129635B - - Google Patents

Description

Fuel composition.

The present invention relates to a fuel composition.

Internal combustion engines, especially with overhead valves, are exposed

for the build-up of significant hard and tough deposits on the inlet valves and valve seats. These deposits have an unholy effect on the running of the engine. When the amounts of these deposits grow, the engine is exposed to loss of power, uneven idling and. sometimes valve burning. When the deposits become very large, parts of them break off and are drawn into the combustion chamber. Cases have been seen of mechanical destruction of pistons and piston rings caused by such deposits.

Considerable work has been done to find the cause and

the nature of these deposits on the inlet valves. The provisions themselves essentially consist of by-products from the fuel combustion and the breakdown of the lubricating oil. Analysis of the deposits types on

that the viscosity-improving additives that are added to the lubricating oil act as binders for the deposits. Polymethacrylate viscosity improvers are, as an example, a class of such substances which seem to contribute strongly to the build-up of these deposits.''

By considering the engine operation will. you can see how breakdown of the lubricating oil can lead to deposits in the fuel intake system. Combustion engines with electric ignition contain a reservoir of lubricating oil -in the sump.-'When the engine is running, the main lubrication is carried out by the sump oil being sprayed and thrown up onto the engine's moving parts and the cylinder walls. Part of, this oil one. however, is pumped under pressure to the upper parts of the engine to lubricate the* moving parts here. In engines with hanging valves, a small stream of the oil pumped to the top of the engine is constantly passed down the inlet and exhaust valve^ stems to ensure that these are constantly lubricated in their bearings when driving. The oil that flows down the inlet valve stem, the valve head and around the valve seat for the inlet valve•is believed to be pyrolysed under the prevailing temperatures and leads to the formation and build-up of the aforementioned deposits.

The problem with such deposits does not occur to a significant extent on or around the exhaust valves and valve seats. It is assumed that this is due to the high temperatures that prevail at and on the exhaust valve during the blow-out period and the effect of the exhaust gases which are carried out at high speed and do not enable the deposition of deposits or continuously burn them off and transport potential deposits away. However, according to the invention, one gets a significant and unexpected increase in the service life of the inlet valve for reasons that are not fully understood.

US Patent No. 3,502,451 relates to a gasoline internal combustion engine fuel composition containing a polymer, copolymer or hydrogenated polymer. In particular, a polymer of -Cg unsaturated hydrocarbon, a copolymer of unsaturated -Cg hydrocarbons or a hydrogenated polymer or copolymer of unsaturated -Cg hydrocarbons with molecular weights between approx. 500 and 3500 in concentrations of between 0.01 and 0.20% by volume•in motor fuel for internal combustion engines with electric ignition. This fuel is effective in preventing or reducing the formation of deposits on the inlet valves and inlet parts of the engine.

According to the present invention, a fuel composition with improved operating properties containing N-polyamine-substituted alkenylsuccinimides is provided, and this composition is characterized by A) a hydrocarbon-based fuel consisting of a mixture of hydrocarbons with a boiling point in the petrol range,

B) 0.000*4 - 0.1 wk. t-%, based on the weight of the composition, of an N-polyamine substituted alkenyl succinimide prepared by reacting an alkenyl succinic acid or an alkenyl succinic acid arihydride of the formula: where R* denotes a hydrocarbon group with molecular weight from 400 to 3Q00, with 0.5 - 2 equivalents of polyamine with the formula:

where x is 1-b and R denotes hydrogen or a lower alkyl group, and C.) 0.003 - 0.20 volume-? of 1) a polymer of an unsaturated t^- to Gg hydrocarbon, 2) a copolymer of an -unsaturated C^- to Cg hydrocarbon or 3) the corresponding hydrogenated polymer or copolymer, which polymer, copolymer or hydrogenated derivatives thereof have a molecular weight of 500 3500.

The discovery of an improved fuel with such a composition was highly surprising and unexpected because N-polyamine-substituted alkenylsuccinimides in motor fuels have no effect in preventing deposits on the inlet valves and valve seats of spark-ignition internal combustion engines.

The R' group in the above formula is a hydrocarbon radical preferably derived from an olefin having from 2 to 5 C atoms. Suitable olefins are ethylene, propylene, 1-butene, 2-butene, isobutylene and amylenes. As mentioned, the group R<1> has a molecular weight from 400 to 3000, which corresponds to approx. 30 to 200 C atoms, with a preferred molecular weight of approx. b00 to 1200, x is preferably a number from 2 to 1 and R is preferably hydrogen. Suitable polyamines and polyalkylene polyamines of the above formula are ethylenediamine, propylenediamine, butylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, dipropylenetriamine, tripropylenetetramine. Dialkylaminoalkyleneamines such as dimethylaminomethylamine, dimethylaminopropylamine, diethylaminopropylamine and the like can also be used.

One half to two equivalents of polyamine is reacted with alkenyl succinic acid >or -succinic anhydride to the reaction product. The calculations of the equivalent quantity of polyamine reactant are based on the nitrogen content, as ethylenediamine has two equivalents per mol. It is preferred to sell approx. an equivalent alkenyl succinic acid :or

-succinic anhydride with approx. one equivalent polyamine.

In a typical preparation, a polyisobutylene-succinic anhydride is produced by reacting a mole of polybutylene with a molecular weight of approx. 1000 with 196 g (2 mol) of maleic anhydride at 200°C for 21 hours. The reaction mixture is cooled and 750 ml of hexane are added. The solution is filtered to remove solid impurities and evaporated in vacuo to remove the hexane. The temperature is then increased to approx. 200°C to remove all traces of excess maleic anhydride.

To a mixture of 1100 g (1 mol) of polyisobutenylsuccinic anhydride and 400 ml of toluene, 52 g (0.5 mol) of diethylenetriamine are added slowly at room temperature. The mixture is heated and the water-toluene azeotrope is collected in a water trap. The reaction is finished when no more water passes over it. The mixture is heated to 100°C under reduced pressure to remove the toluene and a product is obtained which essentially consists of bispolyisobutenyl succinimide.

In another typical preparation, polyisobutylene succinic anhydride was produced by reacting 1 mol of polybutene with a molar weight of approx. 1300 with 196 g (2 mol) of maleic anhydride at 200°C for 24 hours. The reaction mixture was cooled and 750 ml of hexane was added. The solution was filtered to remove solids and evaporated in full vacuum to remove the hexane. The temperature was increased to approx. 200°C to remove all traces of excess maleic anhydride.

To a mixture of 1 mol of polyisobutenylsuccinic anhydride and 400 ml of toluene, 0.5 mol of ethylenediamine is added slowly at room temperature. The mixture is heated and the azeotrope of water and toluene is collected in a water trap. The reaction is complete when it is not

further goes over some water. The mixture is heated to approx. 100 C

under reduced pressure to remove the toluene to give a product consisting essentially of bispolyisobutenyl succinimide.

The polymer used in the fuel according to the invention,

is a polymer produced from an unsaturated hydrocarbon, i.e. a mono-olefin, diolefin or a copolymer thereof, with a number average molecular weight of 500 to 35°0. Blends of olefin polymers with number average molecular weight 4' if falling within this range are also effective. Olefins that can be used to make polyolefin polymers include ethylene, propylene, 1-butene, 2-butene, isobiethylene, amylene, hexylene, butadiene and isoprene. In general, the olefin monomers used for the preparation of unsaturated polyolefin hydrocarbons have from 2 to 6 C atoms. Polyolefin polymers made up of C 1 and C 2 olefins, such as propylene and isobutylene, are particularly preferred according to the invention. Other polyolefins that can be used are prepared by cracking polyolefin polymers or high molecular weight copolymers to polymers falling within the above molecular weight range. Derivatives of the listed polymers produced by saturating these polymers by hydrogenation are also effective and are covered by the invention. The term "polymers" shall include polyolefin polymers and their corresponding hydrogenated derivatives.

The molecular weight of the polymer or polymer derivatives is important for the production of an efficient fuel according to the invention. Effective fuel compositions according to the invention require a polymer or hydrogenated polymer derivative with a number average molecular weight of between 500 and 3500

measured by the osmometry method. Highly efficient fuel compositions are produced from polymers and derivatives thereof with molecular weights within the preferred range of 650 to 2600. Highly efficient fuel compositions can be produced containing polymers with a relatively low molecular weight, i.e. polymers with molecular weights of between 650 and 995•

The process for producing these olefin polymers, copolymers, hydrogenated polymers or copolymers is well known. The determination of the number average molecular weight of the polymers takes place in accordance with the ASTM osmometry method with the designation ASTM D-2503"67. Examples of polymers which are effective in fuel compositions according to the invention^ indicated together with their number average molecular weight^ are as follows: polypropylene 800 , polypropylene 975, polypropylene 1120, polypropylene 1150, polypropylene 1370, polypropylene- 2560, polybutene-I 800, polybutene-1 1200, polyisobutylene 850, polyisobutylene 1000,.polyisobutylene 1200, polyisobutylene 1575, hydrogenated polybutene 1100, - C^-ethylene- butylene copolymer (1:1) 810.

The process for preparing N-polyamine-substituted alkenylsuccinimides is also known. It should be emphasized that suitable N-polyamine-substituted alkenylsuccinimides or mixtures thereof can be obtained commercially. It is appropriate to use the reaction product dissolved in a mineral oil.

The base fuel according to the invention consists of a mixture of hydrocarbons that boil in the petrol boiling point range. This base fuel can consist of straight-chain or branched paraffins, cycloparaffins, olefins and aromatic hydrocarbons, or mixtures of these. The fuel can be derived from directly distilled light petrol, polymer petrol, natural petrol or from catalytically cracked or thermally cracked hydrocarbon and catalytically treated and refined oils,, and boils between approx. 32 and 230°C. The composition of the base fuel itself is not decisive, nor does the fuel's octane number have any noticeable impact on the invention. All the usual types of petrol can be used for carrying out the invention.

The fuel composition according to the invention can contain all the additives that are usually added to motor fuel. E.g. can the base fuel be mixed with an anti-knock compound, such as tetraalkyl lead, i.a. tetraethyl lead, tetramethyl lead, tetrabutyl lead and mixtures thereof, generally in concentrations of from approx. 0.1-1 ml per liter of petrol. The mixture of tetraethyl lead which is commercially available for addition to petrol contains a mixture of ethylene chloride and ethylene bromide which is used as a drifter to remove the lead from the combustion chamber in the form of volatile lead halide. The fuel can also contain all the usual types of anti-condensation additives, corrosion inhibitors, dyes and the like such as e.g. disclosed in US Patents 2,632,695, 2,844,449, 3-325,260, 3,232,724, 2,622,018 and 2,922,708.

The new fuel compositions according to the invention are produced by mixing appropriate amounts of said N-polyamine-substituted alkenylsuccinimides and polymer additives to the starting gasoline. The additives are easily soluble and can be added in the desired order and in the desired manner.

The test methods that have been used to test the fuel compositions were the "Buick Induction System Deposits Test<*> conducted with a 1964 Buick 425 CID V-8 engine. The fuels subjected to these tests were rated for the amount of deposits on the engine's inlet valves and valve seats, which appears in more detail below^

The experiment was carried out with the above-mentioned engine supplied with

a PCV valve ("Positive Crankcase Ventilation" = positive bottom pan ventilation) and connected dynamometer and equipment for regulating speed, load and mtor temperature. The experiment requires approx. 1300 1 petrol and 15 1 lubricating oil per attempt.

For each test, the cylinder head is completely cleaned and new inlet valves are inserted. Care is taken in particular that the clearance between the inlet valve and the valve guide is kept between 0.089 and

0.115 mm. Furthermore, it is ensured that the valve seat widths are between 1.2 and 2.0 mm. The engine block is completely overhauled as stated in the 1964 Buick service manual when compression drops or oil consumption becomes excessive.

The engine is filled with 1 liter of oil and cleaned for 15 minutes at 1,500 rpm. minute. The oil is drained and topped up

new 1 liter of oil after which the experiments begin. The engine is run for 4 periods of b hours each, with a total of 16 periods, i.e. 96 hours, as follows:

After the test run, the cylinder head and valves are removed and the valves are visually assessed for deposits on the valve head area. coated valve. Deposits around the valve seat are graded S - traces, L - light, M - medium, T - thick.

The following examples illustrate implementation of the invention. The starting petrol used was a typical quality petrol containing 0.8 ml of tetraethyl lead per liter of petrol. The base fuel contained 25% aromatic, 20% olefinic and 55% aliphatic hydrocarbons as determined by FIA analysis. The petrol had an initial boiling point according to ASTM of 30°C and a final boiling point of 190°C, and a Research octane number of approx. 100. When nothing else is stated, the starting oil contained 0.5% by volume of commercial additive containing corrosion inhibitor in mineral oil. This additive mixture had no significant effect on the deposits on the inlet valve and valve seat.

A typical petrol without additive according to the invention gives an assessment mark on the deposit on the inlet valve of approx. 6.0, and a valve seat grade of T=thick. An improvement in valve character of 0.5 units better than the base gasoline and usable .valve seat deposition, trace or light, constitutes a significant improvement. An improvement of 1.0 unit or more generally to 7.0 or higher and acceptable grade for deposit on the valve seat is a very significant improvement in engine unit.

Examples 6 and 7 show the application of the present invention and one sees the surprising increase in the cleanliness of inlet valves and valve seats that occurs due to the unexpected interaction between the components of the additive according to the invention.

Claims (10)

1. Fuel composition with improved operating properties containing N-polyamine substituted alkenylsuccinimides., characterized by A) a hydrocarbon base fuel<p>ff consisting of a mixture of hydrocarbons with a boiling point in the petrol range, B) 0.0004 - 0.1% by weight, based on the composition's weight, of an N-polyamine-substituted alkenyl succinimide prepared by reacting an alkenyl succinic acid or an alkenyl succinic anhydride with the formula: where R' denotes a hydrocarbon group with molecular weight from 100 to 3000, with 0.5-2 equivalents of polyamine with the formula: where x is 1-6 and R denotes hydrogen or a lower alkyl group, and C) 0.003 - t3.20 volume-? of in; a polymer of an unsaturated C2~ to Cg hydrocarbon, 2) a copolymer of an unsaturated C2~ to Cg hydrocarbon or 3) the corresponding hydrogenated polymer or copolymer, which polymer, copolymer or hydrogenated derivatives thereof have a molecular weight of 500-3500. 2. Fuel as specified in claim 1, characterized in that R' has a molecular weight of from 800 to 1200. 3. Fuel as stated in claim 1 or 2, characterized in that R' is derived from an olefin with 2 to 5 C atoms. 4. Fuel as specified in one or more of the above requirements, characterized in that R is hydrogen. 5. Fuel as specified in one or more of the above claims, characterized in that x in said polyamine has the value 2 to 4. 6. Fuel as stated in one or more of the above claims, characterized in that the polyamine is diethylenetriamine. 7. Fuel as stated in one or more of the above claims, characterized in that said N-polyamine-substituted alkenylsuccinimide is the reaction product between polybutene succinic anhydride and diethylenetriamine. b. Fuel as stated in one or more of the above claims, characterized in that said polymer of unsaturated hydrocarbon has a molecular weight from b50 to 2600. 9. Fuel as stated in one or more of the above claims, characterized in that said polymer of an unsaturated hydrocarbon is built up from C1 - C2 olefins. 10. Fuel as stated in one or more of the above claims, characterized in that said polymer of unsaturated hydrocarbon is a polypropylene.