US2821174A - Appliance for the ventilation of the crankcase of internal combustion engines - Google Patents

Description

Jan. .28} 1958 A. SCHElTERLEIN 2 7 APPLIANCE FOR THE VENTILATION OF THE CRANKCASE OF INTERNAL COMBUSTION ENGINES 2 Sheqts-Sheei 1 Filed May 27. 1955 INVENTOR.

Jan. 28, 1958 A. SCHEITERLEIN APPLIANCE FOR THE VENTILATION OF THE CRANKCASE OF INTERNAL COMBUSTION ENGINES Filed May 27. 1955 2 Sheets-Sheet 2 INVENTOR.

United States Patent APPLIANCE FOR THE VENTILATION OF THE EIQRINNITIgASE OF INTERNAL COMBUSTION Andreas Scheiterlein, Graz, Austria, assignor to Gustav Ospelt, Vaduz, Liechtenstein Application May 27, 1955, Serial No. 511,719

Claims. (Cl. 121-194) This invention relates to an internal combustion engine, the crankcase of which is ventilated via a separate expanding and condensing chamber.

It is necessary and customary to ventilate the crankcase of four-stroke engines and two-stroke engines without a crankcase scavenging system by maintaining a permanent connection between its interior and the atmosphere in order to avoid power and oil losses due to overpressure which might be produced by piston leakage. Yentilation is of particular importance for two-stroke englnes with piston-controlled exhaust ports, if uncontrollable losses of lubricating oil between the pistons and cylinder walls and through the exhaust ports are to be avoided.

For the purpose of eliminating oil losses through the breather it is known to provide an expanding and condensing chamber along the passage leading to the exhaust port inside the crankcase, permitting the oil contained in the crankcase air in the vapor state to condense and flow back into the oil sump. The exhaust port is usually located at a high level of the crankcase and can be used simultaneously as an oil filler inlet.

In these known designs the arrangement of a separate condensing chamber invariably involves higher cost and the necessity of enlarging the crankcase and consequently, the entire engine. This is particularly true of engines with a lubricating system where oil is intentionally sprayed in the crankcase so as to feed it to certain points requiring lubrication, as a result of which the crankcase air contains a large amount of oil. In order to eliminate these shortcomings the present invention provides for an expanding and condensing chamber formed by the rear gear cover. As a result of this arrangement, the path of the crankcase air to the exhaust port will be lengthened and the oil condensation improved. At the same time, the design of the crankcase is simplified and its construction cost reduced and the overall dimensions of the engine will be smaller.

The expanding and condensing chamber is preferably arranged in the rear gear cover beside the chamber which houses the gears, both chambers being separated from each other at least partly by a partition. This affords a very simple and space-saving shape of the cover and the jointly machined surface of attachment simultaneously provides the closure of the smoothing chamber.

The invention is illustrated by way of example in the accompanying drawings wherein:

Figure 1 shows a vertical section through a twostroke engine, the cover part being shown in section along the line I-I of Figure 2. Figure 2 shows a rear view of the gear cover and Figure 3 a section of this cover along the line IIIIII of Figure 2.

In Figure 1 only the flywheel end adjacent cylinder of the two-stroke engine with cylinders arranged in a row is shown. The crankcase is designated by 1, the cylinder liner by 2, the cylinder head by 3, the piston by 4 and the connecting rod by 5. The end of the crankshaft 6 carries the flywheel 7. Between the flywheel 7 and the last main bearing 8 of the crankshaft, a gear wheel 9 is located on the crankshaft, driving the auxiliary machines not shown, such as the fuel injection pump via the idler 10 and another gear wheel 11. The idler 10 can be designed as a counterbalancing wheel and is mounted on a counterbalaucing shaft 12 passing through the crankcase. The three aforementioned gear wheels 9, 10 and 11 are in alignment and located outside the crankcase 1 and covered by a gear cover 13.

The gear cover 13 is also part of the flywheel housing which is closed by a cover 14. It is secured by screws to the crankcase 1 with the interposition of a plate 15. The bores 16 for the fixing screws are shown in Figure 2. The interior 17 of the gear cover serves to house the gear Wheels 9, 10 and 11. Separated from the chamber 17 by a partition 18, an expanding and condensing chamber 19 is provided in the cover, with its lower portion communicating With the lower bottom half of the crankcase and a vent 20 in its upper portion. The partition 18 is partly bent over the lower gear wheel 9 to prevent oil from being sprayed from the gear wheel 9 rotating in the direction of the arrow 21 directly into the smoothing chamber. The expanding and condensing chamber 19 is upwardly enlarged so that the air flow from the crankcase to the vent 20 will be slowed down still further. In addition, bafile plates 22, 23 of a type known per se are arranged inside this chamber to divert the air and lengthen the flow path. These measures permit the separation of even the smallest drops of oil. The separated oil flows back to the oil sump 24.

The partition 18 and the bafile plates 22 and 23 reach as far as the connecting surface 25 of the gear cover 13 and are machined jointly with the latter. They register with the fiat plate 15 located between the crankcase 1 and the gear cover 13. This provides a lateral separation of the expanding and condensing chamber 19 from the chamber 17 of the gear wheels.

The vent 20 also serves as a filler inlet. For that purpose, a funnel tube 26 is inserted in the vent and surrounded by the housing 27 which can be closed by means of a cover 28. If the cover 28 is closed, the ventilation is effected through the funnel tube 26 and a tube 29 leading downward, of which the upper part only is shown in the drawing.

I claim:

1. In an internal combustion engine of the reciprocating piston type having a rotary crankshaft driven by the reciprocating piston, said engine including a housing having a crankcase in which said crankshaft is rotatably disposed, said crankcase being open at one end, and the corresponding end of the crankshaft projecting through said one end, a gear fixed on said projecting end of the crankshaft, a gear cover closing said open end of the crankcase and housing said gear, means cooperating with said gear cover to define an oil condensing passage extending generally upwardly to one side of said gear from the lower portion of said cover to a vent formed in the upper portion of said cover, said passage being upwardly enlarged to lower the velocity of the air following its entry into said passage to permit an improved separation therefrom of oil particles and oil vapor for drainage into said crankcase.

2. The combination of claim 1 in which the said means cooperating with the cover comprises a flat plate interposed between the upper portion of said cover and the open end of the crankcase and terminating short of the lower extremity of said passage to establish communication thereof with the crankcase.

3. The combination of claim 2 in which said cover is formed with a recess presented toward the crankcase for housing said gear, and provided with an integral partition extending upwardly through said recess on one 5. The combination of claim 4 wherein said bafile side of the gear and in flush engagement with said flat plates extend into flush engagement with the said flat plate to define said passage. plate.

4. The combination of claim 3 including bafiie plates integral with the cover plate and projecting into said 5 References Clted the file of this Patent passage from generally opposite sides thereof to direct UNITED STATES PATENTS the air through said passage in a tortuous path, thereby 1,299,129 Coatalen APR 1, 1919 to prolong the retention of air in said passage and secure improved removal of oil particles and vapor from the air FOREIGN PATENTS within said'passage. 10 415,490 Germany June 25, 1925

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