US 3502451 A
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United States Patent 6 3,502,451 MOTOR FUEL COMPOSITION Fred W. Moore and Bruce S. Bailey, Fishkill, N.Y., as-
signors to Texaco Inc., New York, N.Y., a corporation of Delaware N Drawing. Filed Apr. 29, 1966, Ser. No. 546,212
Int. Cl. C101 1/10 US. Cl. 44-58 14 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a motor fuel composition for a four-cycle, spark-ignited internal combustion engine. More particularly, the invention relates to a motor fuel composition containing polymers and their derivatives as additives in an amount effective to reduce or eliminate harmful deposits on the intake valves and around the ports of an internal combustion engine; The invention also relates to a method for inhibiting the formation of such deposits.
Internal combustion engines of current manufacture are subject to a substantial build-up of tenacious deposits on the intake valves and around the ports of the engines. This condition is particularly true of overhead valve engines. The deposits seriously interfere with the proper functioning of the fuel intake system. When their level has built up, the engine will exhibit substantial loss of power, rough idling and even valve burning. On further deposit build-up, portions will break off to be drawn into the combustion chamber where they can cause further mechanical damage to the engine.
Considerable work has been conducted to determine the-nature and cause of these deposits. The deposits are composed of the by-products of fuel combustion and lubricating oil deterioration. Research has shown that the viscosity index improvers contained in the lubricating oil act as binders for the deposits and that certain types of VI improvers appear to be worse than others. Polymethacrylate viscosity index improvers are one class of materials which appear to contribute materially to the deposit build-up.
An understanding of engine operation will show how lubricating oil deterioration can contribute to deposits in theintake manifold. A spark-ignited internal combustion engine contains a reservoir of lubricating oil in the crankcase. When the engine is running, the greater part of the crankcase oil is splashed up on the operating parts of the engine and on the cylinder walls. A portion of this oil, however, is pumped to the upper parts of the engine to lubricate the working parts therein. In an overhead valve engine, a small stream of the oil pumped to the upper section of the engine is constantly run over both the intake and exhaust valve stems to insure that they are constantly lubricated in their guides during opera- Hce under the temperatures experienced resulting in the laydown and build-up of deposits with the viscosity index improver acting as a binder.
This particular problem is not encountered to any material extent in the exhaust manifold or around the exhaust valves. This is due in part to the fact that there is less oil on the exhaust valves and possibly to the high temperatures existing in the exhaust manifold which either do not permit the laydown of deposits or continually burn off any such deposits that may be laid down.
It has now been discovered that a minor amount of certain polyolefin polymers and their corresponding hydrogenated derivatives dissolved in a motor fuel composition is effective for removing or preventing the formation of deposits on the intake valves and ports of a four-cycle, spark-ignited, internal combustion engine. More specifically, a motor fuel composition comprising a mixture of hydrocarbons boiling in the gasoline boiling range containing from about 0.01 to 0.20 percent of a C to C polyolefin polymer or hydrogenated polymer having an average molecular weight in the range from about 500 to 3500 as determined by an osmometer is effective for removing the aforesaid deposits.
The polyolefin polymers which are employed in the motor fuel of the invention are polymers prepared from monoolefins and diolefins or copolymers of either having an average molecular weight in the range of about 500 to 3500. Mixtures of olefin polymers with an average molecular weight falling Within the foregoing range are also effective. Olefins which can be employed to prepare the polyolefin polymers include ethylene, propylene, butylene, isobutylene, amylene, hexylene, butadiene and isoprene. In general, the olefin monomers from which the polyolefins are prepared are unsaturated hydrocarbons having from two to six carbon atoms. The polyolefin polymers from propylene and butylene are particularly preferred for the practice of this invention. Other polyolefins which can be employed are those prepared by cracking polyolefin polymers or copolymers of high molecular Weight to a polymer in the above-noted molecular Weight range. Derivatives of the noted polymers obtained by saturating the polymers by hydrogenation are also effective and are a part of this invention. The word polymers is intended to include the polyolefin polymers and their corresponding hydrogenated derivatives.
The base fuel of the invention comprises a mixture of hydrocarbons boiling in the gasoline boiling range. This base fuel may consist of straight chain or branched chain paraffins, cycloparaffins, olefins and aromatic hydrocarbons or any mixture of these. This fuel can be derived from straight run naphtha, polymer gasoline, natural gasoline or from catalytically cracked or thermally cracked hydrocarbons and catalytically reformed stocks. The composition of the base fuel is not critical nor does the octane level of the base fuel have any material effect on the invention. Any conventional motor fuel base may be employed in the practice of this invention. The base fuel may contain any of the additives normally employed in a motor fuel. For example, the base fuel may contain an anti-knock compound, such as a tetraalkyl lead compound including tetraethyl lead, tetramethyl lead, tetrabutyl lead, mixtures thereof and the like. The tetraethyl lead mixture commercially available for automotive use contains an ethylene chloride-ethylene bromide mixture 3 4 18 a scavenger for removing lead from the combustion begun. The engine is operated on a four-stage-six-hour :hamber in the form of a volatile lead halide. The motor cycle for a total of 16 cycles or 96 hours as follows:
Fuel may also contain any of the conventional anti-icing additives, corrosion inhibitors, dyes, upper cylinder Cycle Time Hours Operation ,ubricating oils and the like. 1 5 (H 1 Idle The novel fuel compositions of the invention are pre- 1-4 a Road load. pared by mixing a suitable amount of the prescribed polyggg f ner or polymer derived additive to the base gasoline.
The amount of additive employed in the fuel composition s critical in order to realize the benefits of the invention. 10 v Road Heavy 3roadly, the additive must be employed in a range from Operatim Idle Stage load Stage 108d Stage lbOllt 0.01 to 0.20 volume percent. Highly effective re- Speed, 1.p,m 1000 225055 2250545 iults have been realized when the additive amounts to k fig gf-gg 1L 5 315;: 5%; ).05 to 0.15 volume percent of the fuel composition. The Spark Advance, B'I DC 1 a0 0 40 3g preferred concentrat1on of the add1t1ve is an amount from 15 fif gi g figf gi i f gi 3'; 23 Mod-:2 about 0.06 to 0.12 volume percent. Jacket-out templ, F- 200i2 200=i;2 200:1:2 The molecular weight of the polymer or polymer deokcs 235*2 rivative is also critical in preparing an effective fuel com- 2 Typical Values, not controlled. 0 TDC t 600 position according to this invention. Effective fuel com- Appmximate values'spark advance M6 B a positions of the invention require a polymer or hydro- Upon c0rnplet1on of a run, the cylinder heads and genated polymer derivative having an average molecular valves are removed and the valves visually rated for the weight in the range of 500 to 3500 as determined by an extent of deposit build-up on the valve tulip surface. The )srnometer method. Highly eflective fu l compositions intake valve deposits are rated according to a merit ratire obtained with polymers and derivatives having molec- 8 Scale running from 10 t0 The rating 10 is P ilar weights in the preferred range from 650 to 2600. 25 fectly 616311 Valve- The rating 1 is pp to an extremely Very effective fuel compositions can be prepared from ily Coated V ve- Deposits arou d the port Openi g relatively low molecular weight polymers, that is using are rated g Mmedium and ypolymers having molecular weights in the range of 500 The Buick Chassis Dynamometer Test is conducted us- ;0 995. ing a 1964 Buick Wildcat car having a 425 CID V-8 en- Two tests were employed for e l ti h d i i gine. All runs are made at 70 m.p.h. level road condilibiting effect of the novel fuels of the invention. One tiOIlS using a run duration of 56 hours (3920 The Lest is the Buick Chassis Dynamometer Test using a Buick overhaul of the engine and flush Operations are identical Wildcat automobile, The e ond t t i h B i k I d to the procedure described above for the Buick Induction Lion System Deposits Test conducted using a 1964 Buick System Deposits Test- The intake valves and ports are 425 CID V-8 engine. The performance of th t t is rated using the same merit rating scale from the above pased on the ratings of the intake valve and port deposits. test- The Buick Induction System Deposits Test is conducted TWO base fuels were employed in the following examlsing as a test engine, a 1964 Buick 425 cu) V-H en- P Base Fuel A was a typical premium grade gasoline gine equipped i h a pcv (positive crankcase v containing 3 cc. of TEL per gallon. This fuel consisted of :ion) valve and installed on a dynamometer test stand 27 Percent aromatics, Percent Okfills and 5 P i h Supporting equipment to control speed load and c ent saturated hydrocarbons as determined by FIA analygine temperatures This test requires app i t l 350 S15. ThlS fuel had an distillation I.B.P. Of 87 F., gallons of fuel and 4 gallons of lubricant for each run. an of and a research Octane number of Prior to each run, the cylinder heads are completely reconditioned and new intake valves installed. Special care 40 Base ,Fuel B was the Same as Base P A except that nust be taken to assure that the inlet valve-to-valve guide i i i vqlume Rel-cent of a mixture of corro' :learance be maintained between 0.0035 to 0.0045 inch. slon mhlbltor m mmfiral [n addition, the valve seat widths are maintained between $1 2; figgg i igf i sgi if gfi l t and & inch. The engine block is completely overy 1 v6 g valve deposits ratings of 5.9 to 6.1. An improvement in 323F 13? lj g f Wlth g Stated,m the rating to 6.4 is a significant improvement in the deposits ervlce maflua w m ow'by 011 rating and an improvement to 7.0 or above is a very sub- ;l1mpt1011 bGCOIIlC eXceSSlVe. stantial improvement The eIlglIle 1S chafged Wlth four quarts f Oil f The examples in Table I give the results of fuel comillslled 15 mlnutes at 1500 -P- Followlng an 011 positions tested in the Buick Induction System Deposits irain, four quarts of new oil are added and the fuel tests Test.
TABLE I.INDUCIION SYSTEMS DEPOSITS TEST Base Fuel B, Concentration Base fuel A, Concentration 0. 05% 0.075% 0. 10% 0. 10% Additive, Valve Port Valve Port Valve Port Valve Port Valve Port Valve P ort mol. wgt. Rating Rating Rating Rating Rating Rating Rating Rating Rating Rating Rating Rating Runs 1-4, polypropene, 800 6. 4 Runs 5-7, polypropene, 975.." 7. 6
Run 8, polypropene, 1,120 Runt polypropene, 897 1 r Runs 10, 11, polypropene, 1,150
Run 12, polypropene, 1,370-.. Run 13, polypropene, 2,560 Run 14, polybutene, 300 Run 15, polybutene, 730 5 Runs 16, 18, polybutene, 1,100 8.7
Run 19, polybutene, 1,900 9 3 M Run 20, hydrogenated i i u polybutene, 1,100 M-H Run 21, polybutene-1,800 7.8 L Run 22, 1 to 1 03-04 copolymer, 1,010 8. 2 L
Run 23. C2-C4 ethylenebutylene copolymer, 810 30ntrol, no additive 5. 9 H
The outstanding effectiveness of gasolines containing polyolefins and hydrogenated polyolefins within the prescribed concentrations and molecular weight ranges is demonstrated. The ineffectiveness of motor fuels containing low molecular weight polybutene is also demon-' strated.
The examples in Table H show the results of fuel compositions of the invention in the Chassis Dynamometer Test.
TABLE II.CHASSIS DYNAMOMETER TEST Base tuel B, concentration Valve Port Valve Port Valve Port Additive, mol. wt. Rating Rating Rating Rating Rating Rating Run 24, polypropene, 1120 7. 8 T-L Runs 25, 26, polypropene, 1150-.- 7. 8 M 7. 9 L Run 27, polybutene, 1100 7. 1 H
Run 28, blend of 0.0375% 800 M.W.
polypropene and 0.0375% 1,370M W. polypropene, 1,08
Control (no addit The outstanding effectiveness of the fuel compositions of this invention are shown by the high valve rating in this test.
Polymers have previously been added to gasoline in amounts and molecular weight ranges elfective to thicken the gasoline and reduce its flow through the carburetor. Thus, Howard, US. 2,049,062, discloses increasing the kinematic viscosity of gasoline by 4 percent by adding polymers of molecular weights from 2,000 to 270,000. The kinematic viscosity of the base fuel is not materially increased by the addition of the polymer derived additive in preparing the novel fuel composition of this in vention. An amount of polymer which increases the viscosity of the base fuel by less than 1 percent is substanially ineffective for thickening the motor fuel composition.
Viscosity determinations were taken of the two base fuels and the novel fuels of the invention prepared from these base fuels. Kinematic viscosity in Stokes was determined at ditferent temperatures for the base fuels described above and for the novel fuel compositions of the invention prepared from these base fuels.
TABLE III.-EFFECT OF 800 MOLECULAR WEIGHT POLY- PROPYLENE POLYMER ON GASOLINE VISCOSITY Base Fuel B Base Fuel B+0.05% 800 M.W. polypropylene. Base Fuel B+0.075% 800 M.W. polypropylene Base Fuel B+0.1%
M.W. polypropylene Base Fuel B+0.2% M.W. p
The foregoing examples show that there is no increase in viscosity in some cases and where there is a small increase in viscosity it is substantially less than 1 percent and generally less than 0.5 percent.
Obviously, many modifications and variations of the invention may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.
1. A motor fuel composition comprising (A) a hydrocarbon base fuel consisting of a mixture of hydrocarbons in the gasoline boiling range and (B) from about 0.01 to 0.20 volume percent based on said composition of 1) a polymer of a C to C unsaturated hydrocarbon, (2) a 3. A motor fuel according to claim 1 in which said unsaturated hydrocarbon is selected from the group consisting of ethylene, propylene, isobutylene, amylene, hexylene, isoprene and butadiene.
4. A motor fuel according to claim 1 containing from about 0.05 to 0.15 percent of said polymer or copolymer.
5. A motor fuel according to claim 1 containing from about 0.05 to 0.15 percent of polypropylene havin a molecular weight in the range of 650 to 2,600.
6. A motor fuel according to claim 1 containing a copolymer of C to C olefins having a molecular weight in the range of 650 to 2,600.
7. A motor fuel according to claim 1 containing from about 0.05 to 0.15 percent of polypropene having a molecular weight of about 975.
8. A motor fuel according to claim 1 containing from about 0.05 to 0.15 percent of polypropene having a molecular weight of about 800.
9. A motor fuel according to claim 1 containing polybutene-l having a molecular weight of about 800.
10. A method for preventing the build-up of intake valve and port deposits in a spark-ignited, internal combustion gasoline engine which comprises supplying to said engine a motor fuel composition comprising (A) a hydrocarbon base fuel consisting of a mixture of hydrocarbons in the gasoline boiling range and (B) from about 0.01 to 0.20 volume percent based on said composition of (1) a polymer of a C to C unsaturated hydrocarbon, (2) a copolymer of a C to C unsaturated hydrocarbon, or (3) the corresponding hydrogenated polymer or copolymer, said polymer or copolymer having a molecular weight in the range from about 500 to 3,500.
11. A method according to claim 10 in which said polymer or copolymer has a molecular weight in the range of 650 to 2,600.
12. A method according to claim 10 in which said unsaturated hydrocarbon is selected from the group consisting of ethylene, propylene, isobutylene, amylene, hexyl ene, isoprene and .butadiene.
13. A method according to claim 10 in which said gasoline fuel contains from about 0.05 to 0.15 percent of polypropylene having a molecular weight of about 14. A method according to claim 10 in which said gasoline fuel contains from about 0.05 to 0.15 percent of polybutene-l having a molecular weight in the range of about 800.
(References on following page) References Cited UNITED STATES PATENTS Pyzel 44-80 'Lieber et a1. 44--62 5 Clough et a1. 44-62 Clough et a1. 4462 Howard 44--9 8 FOREIGN PATENTS 848,777 9/1960 Great Britain. 993,744 6/ 1965 Great Britain.
DANIEL E. WYMAN, Primary Examiner Y. H. SMITH, Assistant Examiner US. Cl. X.R. 44-62, 80