US1761929A - Crank-case ventilation - Google Patents

Description

June 3, 1930. c. l.. MccUEN CRANK CASE VENTILATIONy Filed May 2, 1928 UNITED STATT-:s PATENTol-FICE CHARLES L. MCCU'EN, 0F LANSING, MICHIGAN, ASSIGNOR TO GENERAL MOTORS COB- PORATION, F DETROI'L'MICHIGAN, A CORPORATION OF DELAWARE CRANE-OASE VENTILATION -Y Application led May 2X 1928'. Serial No. 274,521.

This invention has to do with an arrangement for Ventilating the crankcase of an internal combustion engine to in sure evaporation of diluents from the lubrlcating oil. It is characterized by the employment of a fan to produce a circulation of air through the crankcase. For simplicity the fan is preferably incorporated in the iy-wheel. If the intake of the fan were directly connected to the crankcase quantities of oil would be drawn out along with the air. To avoid this waste of oil I have rovided a tortuous passage between the an and the crankcase, this passage' preferably including the usual valve chamber, and being in part formed by a baiiie directing the air stream toward the low pressure area existing adjacent the center of the fan. The fly-wheel is provided with the usual housing and at the bottom of the housing I have provided a peripheral opening for the discharge of the crank-casel vapors. This opening preferably faces the rear of the car so that the passing air currents exert an aspirating vaction increasing the iow.

Figure 1 is a side elevation of an engine with parts in section showing my improved Ventilating arrangement. l

Figure 2 is a section on line 2-2 of Figure 1.

Figure 3 is a section on line 3-3 of Figure 1.

10 indicates an internal combustion engine of the conventional L-head type provided with valve compartments 12 at the side of the cylinders, and with the usual crankcase 14 serving as a lubricant reservoir. projects through the endv of the crankcase and carries the ily-wheel 18. The fly wheel is enclosed in the usual bell-housing 20. Air is admitted to the crankcase through the breather 22 which may be provided with a cover 24 as shown, or if preferred with an air cleaner to prevent entrance of grit. Upon the forward face of the flywheel 18 I have mounted blades 26 which are of the simple radial t pe shown and throw the air outwardly. t 28 I have in- 16 indicates the crankshaft whichl dicated a passage leading from the valve compartment 12. This passage communicates with the passage 30 form'ed by the disk 32 clamped between the upper portion of the bell housing 2O andthe crankcase. This disk is of semi-circular shape as shown in Figure 3 and is cut away at the center to provide a center intake 33 for the fly-wheel fan. The bell-housing 20 is provided at its lower portion with a port 34: which may be formed by pressing a portion of the metall of the housing inwardly as shown. The port faces rearwardly and is exposed' to the aspirating action of the passing air currents.

The operation of the device is as follows: Air entering the crankcase throu h the breather 22 under the action of t e fan passes upwardly into the valve chambers through the apertures 36 customarily provided around the tappet guides 38 and thence passes along the valve chambers and outwardly through passages 28 and 30 to the center of the {1y-wheel fan. Here the vapors are thrown outwardly by the action of the blades 26 and are eventually discharged through the' port 34. This discharge is facilitated by the suction produced on the port by the air currents sweeping past it as a result of the forward motion of the car.

My system has the advantage that it is simple and that the circulation is positive and is dependent only on engine operation. The path followed by crankcase vapors in their travel toward the fan consists of the valve chambers and the 'passages 28 and 30 and is of suiiciently tortuous character that oil particles are not carried along but are deposited on the walls of the chamber and returned to the. crankcase. By locating the discharge port 34: beneath the vehicle and at the rear I assure that the vapors do not find access to the interior of the car body and Vcause discomfort to the passengers.

I claim:

1. In an automobile, the combination of an engine having a crankshaft and a crankcase serving as a lubricant reservoir, a centrifugal fan on the crankshaft, a casing for t e fan. communicating with the crankcase through a passage extending to a point adjacent the axis of the shaft, said fan casing being provided with a peripheral discharge port, said discharge port facing rearwardly so as to be subject tothe aspirating action of passing air currents.

2. The combination of an `engine including a crankcase provided with an air inlet, a plurality of Ycylinders communicating with the crankcase, a valve compartment extending along one side of the c linders and communicating with the cra case, a Hywheel and a flywheel housing located at one end of the crankcase, said flywheel being rovided with a plurality of fan blades or the centrifugal movement of air, said engine being provided with a passage leading from the adjacent end of the valve compartment to a point near the axis of the iywheel, said fiywheel housing being provided with a peripheral port for the discharge of gases drawn through the crankcase.

3. In an automobile, the combination of an engine having a crankshaft and a crankcase serving as a lubricant reservoir, a centrifugal fan on the crankshaft, a casing for the fan communicating with the crankcase through a passage extending to a point adjacent the axis of the shaft, said flywheel housing-being provided with a, rearwardly opening louver in its underside and adjacent its periphery, subject to the aspirating action of passing air currents to assist in -effecting the discharge of vapors from the crankcase.

In testimony whereof I aiiix my signature.

CHARLES L. MCCUEN.

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