US1631703A - Internal-combustion engine - Google Patents

Description

June 7, 1927.

E. SOKAL INTERNAL COMBUSTION ENGINE Filed 001;. 18. 1926 INVENTOR.

- Patented June 7, 1927.

UNITED STATES PATENT OFFICE.

EDWARD SOKAL, OF BROOKLYN, NEW YORK, ASSIGNOR TOAMERICAN KATALITE COB- PORATION, OF BROOKLYN, NEW YORK, A CORPORATION OF DELAWARE.

IHTEBNAL-COMBUSTIOfi ENGINE.

Application med October 1a, 1926. Serial in. 142,247.

This invention relates to intenal combustion engines, to correlated improvements and discoveries whereby and wherewith the operation thereof is enhanced, and more par- 5 ticularly to the prevention of detonation in the combustion chamber thereof.

An object of the invention is directed to the provision in an-internal combustion engine of an improved detonation counteractant.

Another object is to proyide an improved method of permanently preventing detonation in an internal combustion engine.

A further object is to provide an improved l5 coating composition which may be ailixed to the walls of the combustion chamber of an internal combustion engine to prevent detonation therein.

In my co-pending application, Serial No. 42,583, filed July 9, 1925, I have shown that the tendency toward detonation in an internal combustion engine, particularly the pronounced tendency thereto in high compression engines, may be counteracted by fixedly disposing within the combustion chamber of the engine a material capable of undergoing a reversible endothermic, i.-e., heat-absorbing, change within the range of temperatures and amid the other conditions existent in the engine during operation, by means of which a cooling effect is exerted upon the gaseous mixture within the chamber with a resultant counteraction of detonation.

\Vhile it is well recognized that detonabustion chamber can be counteracted by cooling the mixture, no theory offered in explanation of this phenomenon has been universally acce ted. It is my view that detonation. or necking, in internal combustion engines, is mainly due to a decomposition or breaking down of the unburned fuel, or in other words, to the dissociation of the larger molecules of the fuel under the influence of heat and pressure into a greater number of smaller molecules, whereby there is caused a sudden rise of pressure. This rise of pressure ma not be indicative of the true condition within the whole body of the fuel-air mixture. but is rather in the nature of a localized impact. This view is supported hv the following considerations: First, the detonating tendency of various fuels is practically a function of their then mal stability, for example, the tendency to tion of the gaseous mixture within a comning of the expansion stroke, the peaks becoming smaller each time, and these rises of pressure are of such short duration that the corresponding pressure volume area is too small to represent an ap reciable amount of useful work and hence they manifest themselves as destructive impacts. Third, detonation is accompanied by lost power, deposition of carbon and great loss of heat to the water jacket, which loss of power and deposition of carbon may be considered natural results from the decom osition of the fuel, and the loss of heat to t 0 water jacket is probably due to radiation caused by glowing particles of carbon and to the impacts. Fourth, it has been shown that various factors which cause an increase in the rapidity of combustion and make the combustion more complete have a rather ronounded effect in counteracting detonation. This would seem to follow as an indirect result of the fact that the molecules of the fuel cannot simultaneously undergo a reaction of combustion and of decomposition.

In my coending application above referred to, I ave disclosed as an exemplification of a detonation counteractant suitable for use in accordance with the invention, a material, the melting point of which is such as to render it capable of undergoing a reversible change from solid to liquid state as under the conditions of engine operation, and I have particularly suggested the use of lead, antimony and tellurium.

I have now found as a result of continued experimentation that an especially efiective 1 o detonation counteractant for such use is a non-fugitive, preferably solid, material which is capable under the conditions of engine 0 eration of undergoing a heat-absorbing endothermic) change at the higher 10;; ran e of temperatures existent within the com ustion chamber of the engine in which it is employed so as to be converted into a different non-fugitive, preferably solid, chemical material, which latter material is no capable under the conditions of engine opertion of undergoing, at the lower range of temperatures existent within the combustion chamber, a heat-releasing (exothermic) change so as to restore itself for further heat-absorbing action. It will be realized from the above that I use a material which undergoes a reversible chemical change under operating conditions, and that the original substance disposed within the chamber may contain a material appearing on either side of the equation expressing the change, or both. Accordingly, with a view to simplicity of definition, the term chemically endothermically reactive material, as hereinafter employed, is to be understood to designate either a material falling within the definition of my improved detonation counteractant given above, or a substance which is convertible into such material under the conditions of engine operation. It will be appreciated in this connection that since the invention relates to internal combustion engines, the term chemically endothermically reactive material as employed hereinafter includes only such substances as will undergo the desired reactions within the range of temperatures and under the other conditions found within the combustion chamber of the engine in which it is employed.

A chemically endothermically reactive material is partlcularly advantageous for use as a detonation counteractant within the combustion chamber of an internal combustion engine because of the marked heat ab- -sorption during the endothermic reaction.

with the consequent high cooling effect upon the gaseous mixture. Furthermore. when there is employed a solid material which is converted into another solid material under the conditions contemplated by the invention, a further advantage is to be found in the elimination of any possibility of the loss of the detonation counteractant by the escape of a material which has been converted into a fluid state.

In the practice of the invention a material capable of undergoing a reversible chemical change which is. endothermic during the power stroke, when the temperatures within the chamber are the highest and the consequent tendency toward detonation is the greatest. is fixedly disposed within the combustion chamber of an internal combustion engine. preferably in the form of, or as an ingredient of, a coating applieirl to certain portions of the walls of said chamber. This coating is especially eflective when applied to certain of those port-ions of the chamber walls which are hottest during operation, as, for example, the exposed surface of the piston and/or the exposed surface of the exhaust valves.

The accompanying drawing is a partly memos sectional view exemplifying a form of the invention. In this exemplification a cylinder block 1. together with a high compression cylinder head 2, provides a combustion chamber 3 into which the contacts 4 of a spark plug 5 extend. A portion of the wall of the combustion chamber is provided by a piston head 6 on the surface of which is a coating 7 containing a relatively permanent chemically endothermically reactive material. Another ortion of the wall of this chamber is provided by the surface of an exhaust valve 8 on which there may also be provided a coating 9 which may also contain a relatively permanent chemically endothermically reactive material.

As an exemplification of a suitable material for use in accordance with the invention, mention may be made of lead carbonate (PbCO This material is convertible into litharge (PbO) during the power period of engine operation when the range of temperatures within the chamber is the greatest. and the resultant lead oxide is reconvertible into lead corbonate during those intermediate periods of operation when the range of temperatures within the chamber is lower. This reversible change may be represented chemically by the equation PbCO ASPbO CO A ill) wherein the symbols +A and A indicate within the range of combustion engine temperatures.

It will, of course, be appreciated that in lieu of a carbonate of any particular element there may be employed an oxide thereof which is convertible into the carbonate under the conditions of engine operation; and the term substance of the carbonate-oxide type as used hereinafter, is intended to refer either to a carbonate which is endothermically reactive, or to an oxide, a carbonate, a hydroxide, or other material which is convertible into an endothermically reactive carbonate under the conditions contemplated by the invention. For example, in lieu of a carbonate of lead, litharge or any other oxide of lead which is convertible into an endothermically reactive carbonate of lead under engine operating conditions, may be employed. There may also be used'a mixture of litharge and lead carbonate in suitable proportions, as for example, in substantially equal proportions, whereby the advantages inherent in the use of both mate rials may be utilized.

The litharge possess a somewhat reater initial adhesiveness than the lead car nate, but the presence of lead carbonate in the exposed surface of the initial coating, although not indispensable, is desirable, because if litharge is used, its change into lead carbonate being an expansion in volume, may have a tendency to loosen its contact with the surface beneath, while in the case of lead carbonate the initial change being accompanied by a diminution of volume, there is here by a natural provision made for porosity in the coating to take care of any subsequent changes in volume. It is to be noted in this connection that the chemical changes occurring during ordinary operation probably take place only in the exposed surface layer of the detonation counteractant, and also that even on this layer each molecule of the material is robably not converted under ordinary conditions, but that the reaction occurs merely in a proportion of the molecules sufiicient to exert the required cooling effect or to restore the material for further heat absorption, as the case may be.

It is to be understood, moreover, that the invention is in no wise limited to the use of any particular material or class of materials, but is directed broadly to any relatively permanent material capable of undergoing, un-

der the conditions of engine operation, a reversible heat-absorbing chemical change; and further that the term relatively permanent is intended to apply not only to the improved detonation counteractant, but also to the substance into which it is changed during heat absorption. I w

In order properly to secure it to the chamber walls, the improved detonation counteractant, in finely divided form,"may be admixed with a suitable binder, such as a silicate. For example, an intimate mixture of a finely divided chemically endothermically reactive material with a silicate binder may be applied in the form of a coating on the exposed surface of the piston head, and/or such other portions of the walls as may be desired. The proportions of active substance to the binder may be varied to the requirements of the particular case, and it has been found that satisfactory results are produced when a mixture containing 25% of subdivided litharge, 25% of lead carbonate, and 50% of a silicate is employed, though these proportions may be varied widely. The application may be accomplished by cleaning the desired surface area, coating such area with the detonation counteractant, and baking or setting. This procedure may be repeated if desired until several coats have been applied. The amountof the improved detonation cou'nteractant to be applied in a particular type of engine may be readily determined by suitable tests indicating the proper surface area to be coated in order to obtain efficient operation.

At the present time the phenomenon of detonation, or knocking, during the operation of internal combustion engines is of much interest because, other condtions being equal, it is more pronounced with engines of high compression ratios. Accordingly this tendency to detonate with a given fuel becomes practically a limiting factor for improvement in the thermal efiicienc and power output through an increase in the compression ratio. This is particularly the case with the constant volume cycle, t e of engine which is used almost exclusive y in automobiles and in aeroplanes and also to a considerable extent in small marine and stationary engines.

It is true that there are other limiting factors, such as loss in mechanical efiiciency, which may offset the gain in thermal elliciency after a certain increase in the compression ratio, but the limitation due to the injurious effects of detonation becomes operative before these other limiting factors exert their influence. Accordingly, it will be apparent that the resent invention, because of the marked e ectiv'eness of a chemically endothermically reactive material as a detonation counteractant, will ermit the designing of engines having a higher comprgalssion ratio than has heretofore been poss1 e.

Among the other advantages arising through the utilization of the detonation counteractant, mention may be made of the following: lack of detonation or knocking,

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lower fuel consumption, more flexible 0 eration of the engine, decrease in carbon e osition, and an increase In the thermal e ciency, particularly in connection with the in which the detonation counteractant may function, and while it is supported by known facts, it is to be understood, of course, that the operativeness and racticability of the invention is not depen out upon or limited in any way by the correctness of such theory.

Since certain changes may be made in the detonation counteractant above described, and difierent embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limitsense. t is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In an internal combustion engine, the combination with a combustion chamber, of a relatively permanent detonation counteractant fixedly disposed within said chamber, and consisting of a material which is chemically endothermically reactive under engine operating conditions. 7

2. In an internal combustion engine, the combination with a combustion chamber, of a coating disposed on certain of the walls of said chamber, said coatin containing a relatively permanent material which is chemically endothermically reactive under engine operating conditions.

3. In an internal combustion engine, the combination with a combustion chamber, of a coating disposed on certain of those portions of the walls of said chamber which are hottest under operating conditions, said coating containing a solid material capable of undergoing, under operating conditions, a reversible endothermic chemical change into other solid material.

4. In an internal combustion engine, a combustion chamber arranged for the reception of a gaseous mixture and fitted with a piston presenting an exposed surface to the gases in said chamber, said surface comprising a coating containing a material which is chemically endothermically reactive under engine operating conditions.

5. In an internal combustion engine, the combination with a combustion chamber. and of a metallic salt which is chemically endothermically reactive under engine operating conditions fixedly disposed within said chamber.

6. In an internal combustion engine, the combination with a combustion chamber, of an endothermicallv chemically reactive substance of the carbonate-oxide type fixedly disposed upon certain of the walls of said chamber.

7 In an internal combustion engine, a combustion chamber arranged for the reception of a gaseous mixture and fitted with a piston presenting an exposed surface to the gas in said chamber, said surface comprising a coating containing undergoing a reversible changeinto an oxide under engine operating conditions.

8. In an internal combustion engine, the combination with a combustion chamber, of a coating formed on certain of those portions of the walls of said chamber which are hottest during engine operation, said coating containing an endothermically reactive lead compound.

9. In an internal combustion engine, the

combination with a combustion chamber, of a detonation counteractant fixedly disposed a carbonate capable of within said chamber, said detonation counteractant comprising a carbonate of lead.

10. In an internal combustion engine, the combination with a combustion chamber, of a coating formed on certain of those portions of the walls of said chamber which are hottest during operation, said coating comprising normal lead carbonate.

11. In an internal combustion engine, the combination with a combustion chamber, of a detonation counteractant fixedly disposed within said chamber, said detonation counteractant comprisin litharge.

12. In an internaI combustion engine, the combination with a combustion chamber, 0 a coating formed on certain of the walls of said chamber, said coating containing a carbonate of lead and litharge.

13. As an article of manufacture, a piston head arranged for use within an internal combustion engine, the pressure surface thereof having formed thereon a coating containing a chemically endothermically reactive lead compound of the carbonate-oxide yp 14. In an internal combustion engine, the combination with a combustion chamber, of an endothermically chemically reactive lead compound of the carbonate-oxide type fixedlv disposed within said chamber.

15. In an internal combustion engine, the combination with a combustion chamber, of a coating formed on certain of the walls of said chamber, said coating containing a rela tively permanent material which is chemically endothermically reactive under engine operating conditions, and a binder.

16. In an internal combustion engine, the combination-with a combustion chamber, of a relatively permanent material which is chemically endothermically reactive under engine operating conditions, in finel divided form, intimately admixed with a silicate binder.

17. In an internal combustion engine, the

combination with a combustion chamber, of a coating formed on certain portions of the walls of said chamber, said coating contain ing a carbonate of lead and a silicate.

18. A method of effectingv improvement in the operation of an internal combustion engine, which com rises permanently exposing within the com nstion chamber thereof a material which is chemically endothermical- 1y reactive under engine operating conditions.

19. A method of counteracting detona-' exposing to such charges a solid material capable of undergoing, under engine operating conditions, a reversible endothermic chemical change into other solid material.

20. A method of effecting improvement in the operation of an internal combustion engine, which comprises forming on certain of those portions of the wall of the combustion chamber of the engine which are the hottest during operation, a coating containing a relative y permanent metallic carbonate which is chemically endothermically reactive under engine operating conditions. i

i In testimony whereof I aflix my signature.

EDWARD SOKAL.

19. A method of counteracting detona-' tion of the successive fuel charges in the combustion chamber of an internal combus tion engine, which comprises permanently Patent No. 1,631,703.

exposing to such charges a solid material capable of undergoing, under engine operating conditions, a reversible endothermic chemical change into other solid material.

20. A method of effecting improvement in the operation of an internal combustion engine, which comprises forming on certain of those portions of the wall of the combustion chamber of the engine which are the hottest during operation, a coating containing a relatively permanent metallic carbonate which is chemically endothermically reactive under en ine operating conditions.

In testimony whereof I afiix my signature.

EDWARD SOKAL.

V Granted June 7, 1927, to

EDWARD SOKAL.

It is hereby eertified that error appears in the printed specification of the abovenumbered nt requiring correction as follows: Page 1, line 1, for the misspelled word intend] read internal, and line 49, after the word true insert the word pressure; page 3, line 81, for the mi and that the said Letters Patent shou d conform to the record of the case in the Patent Oflice.

that the same ma lied word condtions; read conditions;

be read with these corrections therein Signed and se ed this 19th day of July, A. D. 1927.

M. J. MOORE, Acting Uonmu'aaimwr of Patents.

Certificate of Correction.

Patent No. 1,631,703. Granted June 7, 1927, to EDWARD SOKAL It is hereby certified that error appears in the printed specification of the abovenumbered patent requiring correctlon as follows: Page 1, line 1, for the misspelled word intenal read internal, and line 49, after the word true insert the word pressure; page 3, line 81, for the misspelled word condtions; read conditions; and that the said Letters Patent should be read with these corrections therein that the same ma conform to the record of the case in the Patent Ofllee.

Signed and sued this 19th day of July, A. D. 1927.

[ l M. J. MOORE,

Acting C am/missionaof Patents.

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