DE1159689B - Lead fuels for internal combustion engines with spark ignition - Google Patents

Description

GERMAN

PATENT OFFICE

L 41118 IVd / 46a ⁶

REGISTRATION DATE: 2nd F E B RU AR 1962

NOTICE
THE REGISTRATION
AND ISSUE OF

EDITORIAL: DECEMBER 19, 1963

The invention relates to leaded fuels for internal combustion engines.

It is known that such fuels can be obtained by adding small amounts of so-called "liquid lead". to improve. Such additives generally contain at least one polyalkylated lead compound, such as tetraethyl lead, tetramethyl lead, diethyldimethyl lead or tetraisopropyl lead, together with one appropriate amount of at least one lower haloalkane compound, such as ethylene dichloride, ethydibromide, Tetrachloroethane, 1,2,2-trichloropropane, 2,3,4-trichlorobutane, 2-chloro-2,3-dibromobutane.

Although the use of tetraethyl lead and ethylene dichloride the use of gasoline fractions has increased significantly as fuel for modern high-compression engines, it still makes certain new ones Problems emerged, especially those of pre-ignition and spark plug contamination. These problems are mainly due to the fact that the effectiveness of the tetraethyl lead The added cleaner is not sufficient to remove all lead deposits from the combustion chamber. It was found that the deposits that remained there were responsible for these adverse phenomena, such as pre-ignition and soiling of the spark plugs are also responsible.

In the case of the former, the lead deposits lead to the ignition of the fuel before the the exact point in time at which the spark plug would normally ignite. The pre-ignition is noticeable by a sharp whistling (or ringing) in the engine and results in undesirable performance losses.

The second phenomenon, the fouling of the spark plugs, is caused by the build-up of lead Deposits on the electrodes of the spark plugs. When these deposits build up, the electrical discharge no longer generates a sufficiently strong spark, and so does the fuel-air mixture is no longer ignited. This leads to a loss of performance, which of course also the Reduced profitability.

The problem to be solved is to find fuels that have only a lower tendency to pre-ignite and for candle fouling, the octane number as a result of the new additive is only slightly reduced, and their dissolved phosphorus compounds not by water or be leached by aqueous salt solutions.

This multifaceted task is now justified by the invention by the proposal, in the leaded Fuel a small amount of trimethyl blended fuel

for internal combustion engines

with spark ignition

Applicant:

The Lubrizol Corporation, Cleveland, Ohio (V. St. A.)

Representative:

Dipl.-Ing. Dipl. Oec. publ. D. Lewinsky, patent attorney, Munich-Pasing, Agnes-Bernauer-Str. 202

Claimed priority: V. St. v. America of February 14, 1961 (No. 89 133)

Clark Ober Miller, Cleveland, Ohio (V. St. A.) has been named as the inventor

Incorporate phosphorothionate, which is sufficient to reduce pre-ignition and candle contamination. The addition is generally between 0.1 and 1.0 times the theoretical amount, calculated on the amount of lead present in the leaded fuel. The values 0.1 and 1.0 times the theoretical amount show the amount of trimethyl phosphorothionate present in the leaded fuel, which is sufficient to convert 10 or 100% of the lead into normal lead phosphate - Pb ₃ (PO ₄ ) if the conversion is complete. ₂ - convict. 0.5 times the theoretical amount of trimethyl phosphorothionate in a leaded fuel would therefore be sufficient with complete conversion to convert 50% of the lead into normal lead phosphate. It has been found that the addition of less than 0.1 times the theoretical amount of trimethyl phosphorothionate has hardly any effect on pre-ignition and candle soiling and that more than 1.0 times the theoretical amount is effective, but only offers a slight additional benefit brings and is therefore not preferred in the context of the invention. From the standpoint of economy such as actually reducing pre-ignition and candle fouling, between 0.2 and 0.5 times the theoretical amount of trimethyl phosphorothionate is particularly preferred.

309 769/220

The leaded fuel to which the trimethylphosphorothionate is added is a petroleum fraction that boils in the gasoline range (approximately between 10 and 230 ° C) and those with about 0.5 to 8 ecm of tetraethyl lead and halogen detergent per gallon is offset.

The effectiveness of the propellants according to the invention in terms of reducing pre-ignition is proven by the results of the following test runs.

Ignition advance test

The apparatus for this test consists of a 1957 Cadülac V-8 engine running at 4800 rpm 300 hp that can be measured. The following changes have been made:

The automatic starter has been replaced by a manually adjustable one; Control throttle valves as a control mechanism for a regular run were installed; the distributor was through replaced one of a 1955 Cadillac model with an opening mechanism and a Advance ignition counter was equipped. The pre-ignition counter was suitably using Connected special ionization candles, which were mounted in each cylinder of the engine and were used to display and count all spark ignitions other than the desired ones. Also were Thermocouples attached to the engine, which the temperatures of the cooling water and the lubricant indicated.

The control mechanism for normal operation described above left the engine repeatedly according to the following Work cycle:

5
Time
Minutes Speed
age
Around Performance
knife
power
in braking horsepower Oil tem
temperature
⁰ C water
exit
temperature
⁰ C ¹⁰ 3
1 1400
500 11.5
no
(Idle) 85 ± 1
85 ± 1 77 ± 1.5
77 + 1.5

Air-fuel ratio 13.3 + 0.2.

After every 2 hours, the normal run was for a 3-minute count of the pre-ignition occurring interrupted while the engine accelerates to an output of 60 braking horsepower at 1500 rpm became. Then the normal running of the engine was resumed, maintained for 2 hours, interrupted for a 3-minute count of the pre-ignition, switched back to regular operation, etc. This cycle of operation was continued until the number of pre-ignitions reached an equilibrium the engine running on the control gasoline. The engine was stuck with the white spirit operated and subjected to the same repeated test cycle as described above until the Number of pre-ignitions had reached a second equilibrium, at which point the trial considered was considered ended.

The effectiveness of the test fuel in reducing pre-ignition is shown by the following Factor shown:

Equilibrium number of the test fuel

Equilibrium number of the KontroU fuel 100.

This factor shows the pre-ignition number of the test fuel as a percentage of that of the control fuel. The lower the factor, the more effective the fuel is in reducing of pre-ignition.

The trials were carried out with a good quality commercial bleached catalytically cracked one Fuel (leaded with 3 ecm per gallon of a mixture of tetraethyl lead, ethylene dibromide and Ethylene dichloride in such quantities that 1.0 bromine atoms and 2.0 chlorine atoms meet a lead atom) carried out with and without the addition of trimethyl phosphorothionate, the effectiveness of the latter Connection regarding the reduction of pre-ignition is evident:

Table I.

Trimethyl phosphorothionate additive
(Factor of the theoretical amount)

core (blind test)
0.2
0.5

Pre-ignition number factor

100 36 16

After using the above values, the reduction in pre-ignition in internal combustion engines is achieved the fuel preparations according to the invention was shown, tests were also carried out about the effectiveness of trimethyl phosphorothionate in terms of reducing candle soiling, the occurs with leaded fuel.

Spark plug contamination test

The experimental apparatus consisted of a CLR motor from Laboratory Equipment Corporation, the connected to a Midwest Universal Type 758 dynamometer.

The engine was brought into equilibrium (with a good quality of a commercially available leaded fuel):

Speed 1500 ± 25 rpm

Load 17 + 0.1 lbs

Outlet water temperature .... 79 ± 1 ° C

Oil sump temperature 74 ± 1 ° C

Ignition point 25 ° in front of

rem dead center

Air to gas ratio 14.5 ± 0.1: 1

When the engine reached equilibrium, it was stopped and a new spark plug was installed. The engine was started again and after 2 minutes with the throttle valve wide open with the Load rheostat accelerated to 3500 rpm. the

The seconds required for this have been recorded as the acceleration time for a new spark plug.

Eight spark plugs that lasted 50 hours in a Cadillac V-8 engine (powered by a test fuel) used in the pre-ignition test described above were now tested in the CLR engine, with an average Acceleration time for used spark plugs was obtained.

The first test with a new spark plug was repeated and the measured acceleration time with the first measured time to an average acceleration time for new spark plugs summarized.

The factor

average acceleration time of a used candle average acceleration time of a new candle

was used as the »corrected acceleration time of a used spark plug« (hereinafter »AUSPAT« noted) for the test fuel.

The above procedure was repeated with eight spark plugs, used every 50 hours in a Cadillac V-8 engine (operated with a control fuel) in the pre-ignition test described earlier were used. In this way the "AUSPAT" for the control fuel was obtained. In in each case, the determination was also carried out with a new spark plug to avoid any Eliminate the effects of the prevailing air pressure, humidity, etc. on the acceleration time.

The relationship

Test fuel »AUSPAT«

Control fuel »AUSPAT«

is a measure of the effectiveness of the test fuel in reducing candle soiling. If the spark plugs are dirty, it takes an engine longer to reach a certain speed to accelerate. The lower the »AUSPAT« ratio, the more effective the test fuel is regarding a reduction in candle pollution. Explain the information in the tables the beneficial influence of trimethyl phosphorothionate:

Table II

Driven fuel * plus

0.2 times the theoretical amount of trimethyl phosphorothionate

No phosphorus addition (blind test)

"AUSPAT" ratio The addition of 0.1 times the theoretical amount of trimethyl phosphorothionate to a commercially available leaded fuel sets the anti-knock value of this fuel only by 0.04 octane number units (according to ASTM D 908-55 Research Method) or by 0.01 octane number units (according to ASTM D 357-53, motor method). With a higher addition of trimethyl phosphorothionate of 0.3 times the theoretical amount, the anti-knock value only decreases 0.08 or around 0.07 octane units, measured according to the same ASTM methods.

In some cases the fuel is stored in contact with water or aqueous salt solutions. Obviously, any fuel that contains water-soluble material will tend to be water-soluble Loss of material in contact with water or aqueous salt solutions. Some phosper compounds, previously used for use in fuel preparations the disadvantage of a noticeable water solubility. So is z. B. trimethyl phosphate is sufficiently effective regarding the reduction of pre-ignition and candle staining, but so easily soluble in water, that it has therefore found little economic importance as a fuel additive. Unexpectedly Trimethyl phosphorothionate is only slightly soluble in water. Therefore occurs when inventive Fuels stored in contact with water or aqueous salt solutions are not essential Loss of the phosphorus compound. The resistance of the propellants according to the invention versus extraction with water are shown by the data in Table III.

Table III

0.60 1.0

* Commercially available, catalytically cracked fuel containing 3.0 ecm of a mixture of tetraethyl lead per gallon. Contains ethylene dibromide and ethylene dichloride in such amounts that 1.0 bromine atoms and 2.0 chlorine atoms per lead atom meet.

In order to meet the strict requirements that the petroleum industry places on commercial fuels it is also necessary that no improver added to the fuel particularly disadvantageous for the octane number required for the engine or the anti-knock value of the fuel affects. Suitable tests have shown that the fuel preparations according to the invention are particularly satisfactory with respect to both of these requirements.

plus the theoretical Percent phosphorus, the the sample the theoretical Trimethylphosphorus determined in the end after Trimethyl-phos- gangly 3 minute phorthionate sample Shake with 0.2 times 4 volume lot percent phat. distilled water 0.0018 0.0014 0.0018 0.0008 Commercially available leaded fuel 0.2 times lot

* The analytical method used is described in: Analytical Chemistry, B. 32, p. 374 (1960).

Except tetraalkyl lead, haloalkanes and trimethyl phosphorothionate the propellants according to the invention can also use other customary additives included, such as B. dyes, antioxidants, such as 2,6-di-tert-butyl-4-methyl-phenol, corrosion inhibitors, such as alkylated succinic acids, amine salts of dioctylphosphoric acid, antistatic agents and antifreeze agents.

Claims (2)

PATENT CLAIMS: 1. Leaded fuels for internal combustion engines with spark ignition, characterized in that they have a small, pre-ignition and Contain a sufficient amount of trimethyl phosphorothionate to reduce candle staining. 2. Led propellants according to claim 1, characterized in that they are about 0.1 to 1.0 times the theoretical amount of trimethylphosphorothionate. Considered publications: German patent application N 4011 IVc / 46a ⁶ ίο (published on June 18, 1953); German Patent No. 855 480; French Patent No. 1043 087; Belgian patent specification No. 530 652. ® 309 769/220 12.63