US2763247A - Means for reducing formation of engine deposits - Google Patents

Description

Sept. 18, 1956 B. s. BAILEY 2,763,247

MEANS FOR REDUCING FORMATION OF ENGINE DEPOSITS Filed Dec. 31, 1952 2 Sheets-Sheet 1 5,?0055. 5A IL. 5 Y

FEE-

ATTORNEY m INVENTOR. l

Sept. 18, 1956 B. s. BAILEY 2,763,247

EANS FOR REDUCING FORMATION OF ENGINE DEPOSITS Filed Dec. 31, 1952 2 Sheets-Sheet 2 INVENTOR. Bfiuct'fl 5A /45 V ATTORNEY United States Patent MEANS FOR REDUCING FORMATION OF ENGINE DEPOSITS Bruce S. Bailey Beacon, N. Y., assignor to The Texas Company, New York, N. Y., a corporation of Delaware Application December 31, 1952, Serial No. 329,014

3 Claims. (Cl. 123-4136) This invention relates to an apparatus for reducing the formation of lubricating oil sludge, and other engine deposit producing materials, in internal combustion engines.

Formation of engine deposit producing materials such as sludge, varnish, and lacquer in the lubricating oil is, of course, highly undesirable, since they tend to clog the lubricating oil circulation system, which may result in damage to the moving parts of the engine due to improper lubrication. Prevention or reduction of their formation, therefore, is highly desirable.

It is well known to the prior art that lubricating oil sludging, and formation of other engine deposit producing materials such as varnish and lacquer, depends upon a number of factors such as fuel quality, lubricating oil quality, engine design, and engine operating conditions. It is also well recognized that one of the important steps in the process of formation of sludge and other engine deposit producing materials in the lubricating oil of conventional internal combustion engines is the collection in the lubricating oil of constituents such as water, unburned fuel fragments, oxidized hydrocarbons, and other undesired diluents. These constituents usually are produced as a result of the combustion process in the combustion chamber of the engine, and gain access to the lubricating oil reservoir by way of the crankcase, into which they are forced or blown past the piston rings by the gas pressure in the combustion chamber. These combustion chamber products, which generally enter the crankcase in vaporous form, or in gaseous solution in the cylinder lubricating oil film, are sometimes called blowby gases in recognition of their forced leakage past the piston.

The present invention arises from the discovery that the extent of sludging and formation of other engine deposit producing materials in the lubricating oil can be greatly reduced by removing these vaporous combustion chamber products from the crankcase through ventilation and, while so removing them, by reducing the possibility of their condensation into the lubricatingoil, especially by preventing their contact during removal with surfaces having a temperature below their dew point. The invention thus involves removingthe vaporous products from the crankcase by ventilation, and so controlling the temperature of surfaces with which the vaporous products being removed are likely to come in contact that the temperature of these surfaces is maintained above the dew point of the vaporous products, and contamination of the lubricating oil resulting from their condensation is prevented.

It is an object of my invention, therefore, to provide an apparatus for reducing the formation of engine deposit producing materials, such as sludge, varnish, and lacquer,

in the lubricating oil of internal combustion engines.

It is another object to provide an apparatus for facilitating the elimination of vaporous products from the crankcase atmosphere of internal combustion engines.

2,763,247 Patented Sept. 18, 1956 It is another object to provide an apparatus for maintaining the temperature of portions of a crankcase ventilation system at temperatures substantially higher than the ambient level.

It is another object to provide a heating system for the crankcase outlet ventilation pipe of an internal combustion engine.

It is another object to provide means for heating the crankcase outlet ventilation pipe of an internal combustion engine which is simple and inexpensive, and is particularly suitable for adaptation to conventional engine structure.

These and other objects of this invention will be apparent from a consideration of the following description taken in conjunction with the accompanying drawings which disclose one embodiment of the invention. It will be understood that the details of construction and arrangement of parts shown and described may be varied in many ways without departing from the spirit of the invention, for a definition of the limits of which reference should be made to the appended claims.

In the drawings:

Fig. 1 is a simplified sectional view of a conventional multi-cylinder internal combustion engine of the automotive type, taken in a plane perpendicular to the crankshaft.

I Fig. 2 is a simplified view of one side of the engine of Fig. l, constructed in accordance with the present invention.

Fig. 3 is a modified form of the engine structure shown in Fig. 2.

Briefly stated, my invention contemplates the provision of a heating system for the portions of the crankcase ventilation ducting with which the above-mentioned vaporous lubricating oil contaminants are likely to come in contact during their removal from the crankcase atmosphe're. The heating system serves to raise the temperature of the outlet ventilation ducting well above the ambient level, to a temperature above the dew point of the vaporous products in the crankcase atmosphere, and thus eliminates condensation and drainage into the lubricating oil of the above mentioned constituents, such as water, unburned fuel fragments, oxidized hydrocarbons and other diluents which are likely to cause formation of sludge and other engine deposit producing materials. The invention contemplates that heat may be derived from a conventional source of waste heat on the engine, such as the exhaust gases or engine combustion chamber coolant, etc. It is also contemplated that some of the kinetic energy of the heating fluid chosen may be utilized to assist in the ventilation process.

Referring to Fig. 1, there is shown a simplified crosssectional view of an internal combustion engine taken in a plane perpendicular to the crankshaft and including a cylinder 1 and a reciprocating piston 3 connected by a connecting rod 5 to a crankshaft 9 enclosed within a crankcase 11. The crankshaft is mounted in bearings, not shown, which together with the other internal moving parts of the engine are lubricated by oil supplied under pressure from a conventional lubricating oil pump, not shown, which takes suction from an oil sump or reservoir 17 consisting of a pan 18 fastened to the underside of the crankcase 11.

Cylinder 1 is provided with the conventional coolant jacket "19 through which water or an equivalent coolant is circulated by a water pump, not shown, to prevent overheating of the cylinder walls. The engine also includes an exhaust manifold 21, which communicates with the combustion chamber through exhaust port 23 and an engine timed exhaust valve 25, and serves to carry away waste 'hot combustion gases.

Crankcase 11 is provided with an opening 29 in its upper side which is connected to the outside atmosphere or an equivalent source of ventilating air through an inlet crankcase ventilation pipe 31. Another opening. 32 in the upper side of crankcase 11 communicates with the outside atmosphere through an outlet ventilation pipe or duct 33. The outer end 34 of ventilationpipe 33 is preferably cut on the bias and oriented to induce a suction in pipe 33 when the vehicle propelled by the engine moves through the air. Alternatively, any desired means may be used to induce a low velocity ventilation of the crankcase atmosphere, providing fresh air through inlet pipe 31, and exhausting undersired vaporous products through pipe 33.

In operation of the engine, combustion in the cylinder 1 produces among the combustion products water vapor, oxygenated fuel fragments, and other diluents capable of contaminating the lubricating oil, and producing sludge and other engine deposit forming materials therein. Some of these hot combustion chamber products are forced or blown past the piston 3 by the high combustion chamber pressure, and travel down the walls of cylinder 1 into the crankcase 11, where they mix as vapors with the crankcase atmosphere.

In accordance with this invention, the crankcase outlet ventilation pipe 33, and the area surrounding its point of entrance through the wall of crankcase 11, is surrounded with a jacket 35 through which is adapted to flow a heating fluid, for elevating the temperature of the walls of ventilation pipe 33 above the dew point of the vaporous products in the crankcase atmosphere. The heating fluid for jacket 35 may conveniently be obtained by utilizing a portion of the waste exhaust gases, by tapping into the exhaust pipe 23 through an inlet pipe 37 and returning the exhaust gases from which heat has been extracted in jacket 35 through an outlet pipe 39, Fig. 2, to exhaust pipe 23. Alternatively, the jacket 35 surrounding the ventilation pipe 33 may be supplied with hot water from the engine cylinder coolant jacket 19, or crankcase ventilation pipe 33 may be surrounded with an electric heating coil supplied with current from the conventional electric current source associated with the engine.

In an additional modification, as shown in Fig. 3, the waste exhaust gases being circulated through the heating jacket 35 are then passed through a venturi 51 which is connected to the outlet end 34 of the ventilation pipe 33 to assist in the suction of air through the crankcase 11 and its ventilation out of pipe 33.

While the reason for the effectiveness of heating the ventilation pipe 33 upon the prevention of sludge formation is not completely understood, it is believed that the ventilation pipe 33 normally operates as a reflux con denser. Thus, when it is exposed to the ambient temperature of the outside air, which is normally considerably below the dew point of the vaporous products suspended in the crankcase atmosphere, the walls of the ventilation pipe 33 provide a surface upon which a large portion of the vaporous products being ventilated condenses out and drains back into the lubricating oil reservoir 17 in liquid form.

By the heating means above described, it is desirable in accordance with this invention to maintain the temperature of the walls of the crankcase outlet ventilation pipe 33 at or above 70 F. This temperature substantially diminishes the tendency of the walls of the ventilation pipe 33 to act as a condenser for the water vapor, fuel fragments and other diluents in the crankcase atmosphere, and with the ventilation pipe 33 maintained at this temperature or higher it has been found that condensation is sufficiently eliminated to reduce substantially the formation of sludge in the lubricating oil reservoir 17.

As an example of the beneficial effect of facilitating ventilation of a crankcase atmosphere without condensation of the vapors therein and resultant drainage back into the lubricating oil and contamination thereof, the

4 1 results of tests on one conventional internal combustion englne are reproduced herewith:

Engine speed 1825 R. P. M.

Fuel/air ratio 0.071.

Duration 40 hr.

Operation Intermittent. 3 hr. shutdown at 10, 20, and 30 test hrs.

Spark advance 22.5 degrees.

Fuel Thermally cracked naphtha.

Jacket temp., F 100 Oil temp., F 150 Breather temp., "F 50 100 Deposited sludge, grams 5.14 0.70

Undeposited sludge, grams 4.50 4.59

Total sludge, grams 9.64 5.29

It will be apparent from the above data that when the breather temperature, which is the temperature of outlet ventilation pipe 33 and the area surrounding its point of entrance through the wall of crankcase 11, as shown in the drawings, was increased from 50 F. to 100 F., the

rate of formation of total sludge was reduced from 9.64

grams accumulated during the 40 hour test to a rate of 5.29 grams accumulated during the 40 hour test. This represents a substantial reduction in the formation of engine deposit producing materials, by a factor of approximately two.

Thus, there has been shown and described an apparatus for reducing the formation of sludge and other engine deposit producing materials in the lubricating oil of internal combusion engines by providing for adequate heating of portions of the crankcase ventilation system to eliminate condensation of vaporous oil contaminants into the lubricating oil during their ventilation from the crankcase atmosphere.

Obviously many modifications and variations of the invention, as hereinbefore set forth, 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.

I claim:

1. In an internal combustion engine including a cylinder with a reciprocating piston therein forming a combustion chamber, a crankcase and a reservoir for lubricating oil joined thereto enclosing combusion products leaking from said combustion chamber, inlet and outlet ventilation ducts leading from said crankcase directly to the outside atmosphere for supplying fresh air thereto and for removing combustion products therefrom respectively, means for reducing formation by condensation from said combustion products of sludge and other engine deposits in said lubricating oil comprising means for heating the outlet ventilation duct surrounding the same from its junction with said crankcase to the vicinity of its opening to the outside atmosphere thereby to maintain said outlet ventilation duct at a temperature above the dew point of said combustion products.

2. The engine defined by claim 1 wherein said means for heating comprises a fluid jacket joined to means for supplying hot engine exhaust gases thereto.

3. In an internal combustion engine including a cooling water jacketed cylinder with reciprocating piston therein forming a combustion chamber, a crankshaft, piston connected driving means for said crankshaft, a crankcase surrounding said driving means and adapted to enclose combustion chamber gases leaking past said piston, a lubricating oil reservoir exposed to said combustion chamber gases within said crankcase, and inlet and outlet ventilation ducts therefor open to the atmosphere for supplying fresh air to said crankcase and removing said combustion chamber gases from said crankcase, means for reducing formation of engine deposit producing ma- References Cited in the file of this patent UNITED STATES PATENTS 1,306,496 Mohrdieck June 10, 1919 6 Du Pont Feb. 28, 1922 Kukovac Aug 6, 1929 Ellis Oct. 29, 1929 Syrovy et a1 Oct. 20, 1931 Worbois Feb. 17, 1931 FOREIGN PATENTS France Oct. 14, 1919

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