US2450864A - Crankcase ventilating apparatus - Google Patents

Description

1948- c. R. CALLAWAY El AL 2,450,864

CRANKCASE VENTILATING APPARATUS I v Filed April 4, 1947 2 Sheet-Sheet 1 Pal 6H5 FLOW CUBIC FEET PER MINUTE O .5 2 5 3 4 5 6 7 B 9 I0 H 12 I3 I I5 I6 VAUUMIN INS 0F MERCURY INVENTORS cLn/eE/vce e. caunwm FRANK e. ou/v/v HTTORNSY Oct. 5, 1948. c. R. CALLAWAY ET AL 2,450,864

CRANKCASE VENTILATING APPARATUS '2 Sheets-Sheet 2 f l I I l l Filed April 4, 1947 flTTOR/VEY Patented Oct. 5, 1948 UNITED STATES CRANKCASE VENTILATING APPARATUS Clarence R. Callaway, New York, Y., and I Frank R. Dunn, Little Ferry, N. J., asslgnors to Motor Economy Prgductalnc New York, N. Y., '--Tcorpo ration o'f'New Jersey Application April 4,1947, Serial lilo. 739,488 Claims. (Cl. 123-196) ing crank cases of internal combustion engines and more particularly to an improved apparatus for positively withdrawing vapors and unburnt products of combustion from the crank case at a controlled rate which is a function of the pressure existing in the intake manifold of the internal combustion engine.

In the operation of internal combustion engines, gases and vapors find their way past the piston rings-into the crank case. The heated products which blow by the piston rings contain water v'apor,-carbon dioxide, carbon monoxide, unburnt fuel in vapor form and hydrocarbon combustion products such as ketones, lactones, naphthenic acids, certain heavier hydrocarbons which form sludge and finely divided carbon. The condensable vapors and heavier products become entrained in the lubricatingoil and gradually contaminate it. Furthermore, the corrosive oxidation products and sludge acids have a detrimental effect upon the bearings of the engine. The ordinary means for ventilating crank cases are inefficient and insufficient to remove the deleterious by-products of combustion which blow by the piston rings-with the result that in a comparatively short period of time the lubricating oil in the crank case becomes contaminated.

Attempts have been made to ventilate the crank case by withdrawing the products of combustion therefrom under the influence of the reduced pressure existing in the intake manifold of the engine. be controlled. If the volume of gases fed into the intake manifold be too great, there is a dilution by the gases of thefuel vapors going into the cylinders of the engine, causing loss of 'emciency,

back-firing and overheating.

Then, too, the increase of the pressure within the intake manifold results in imperfect carburetion if the pressure is increased too much.

Accordingly, there must be control means in the system which will govern the volume of gases fold through a control valve. The control valves of the prior art, however, have been inoperative to accomplish the desired results. One example of an attempt to solve the problem is shown in the Krieck Patent, 1,990,657, dated February 12,

The reduced pressure, however, must .2 v I In the Krieck patent, the mixture from the crank case is passed into a glass bowl and then through a filter. The result is that the carbon and sludge soon collect in the glass bowl and 5 render it opaque, making it impossible after a short time to determine the level of the con-i densate within the bowl. We overcome this dif ficulty in the present case by passing on the products withdrawn from the crank case first through the filter so that the sludge, carbon and other discoloring compounds are disposed in the filter, leaving the glass bowl relatively clean so that it may be emptied at periodic intervals when observation indicates the level of liquids in the bowl is such as to require emptying.

In the Krieck structure, the valve is completely open at low vacuums. This makes it difllcult and sometimes impossible to start the engine since at low vacuums all of the vacuum is required for carburetion in order that fuel may be fed to the engine. Then, too, in the Krieck structure when the vacuum becomes high, the valve closes completely so that all beneficial effect is lost. In practice the Krieck structure gives results only within a very limited range of operation of the engine.

One object of our invention is to provide an 1 improved structure which will minimize the disadvantages of the prior art.

Another object of our invention is to provide an apparatus in which the transparent collecting receptacle will remain clear for long periods of time.

Another object of our invention is to provide an apparatus in which the control of the fiow of Vapors into the intake manifold is maintained so that loss of vacuum at starting and low speeds is avoided and too great dilutions of the fuel mixture at high speeds is likewise avoided.

In general our invention comprises a filter, a transparent collecting receptacle and a control valve. The vapors from the crank case are withdrawn and led to the filter, thence through a transparent collecting receptacle, through a controlvalve to the intake manifold of the engine. The control valve is such that at low vacuums only a small predetermined port is presented. At high vacuums, only'a small predetermined port of another'area is presented. At vacuums between low and high vacuums, the valve is such that the rate of flow is controlled as a function of the reduced manifold pressure in order to maintain a rate of flow between predetermined limits.

In the accompanying drawingswhich formpart of the instant specification and which are to be Figure is an elevation of the oppositgside of the control valve per se showing another of its ports.

Figure 6 is a graph of gas flow through the valve in cubic feet per minute plotted against the partial vacuum existing in the intake manifold in inches of mercury.

More particularly, referring now to the drawings, a housing 8 is secured by strap iii to any appropriate support adjacent the internal combustion engine, the crank case of which is to be ventilated. A conduit I2 is connected in any suitable manner to the crank case of the internal combustion-engine and communicates with the interior of the housing 8. The lower periphery of the housing 8 is formed with an internally threaded flange i4 in which is threadedly seated a transparent collecting bowl is made-of glass or other suitable transparent material. The upper edge of the collecting bowl i6 supports a perforated plate i8 upon which rests a filter 20 of any appropriate construction. A wad of fibrous material such as steel wool, glass fibers or the like is vitable. Threadedly positioned in the upper wall 22 of the housing 8 is a pipe 24 which extends through the filter 20 and through the perforated disk II, as can readily be seen by reference to Figure 1.

The pipe 24 extends outside of the upper wall 22 of the housing 8. Threadedly secured to its outer end, we provide valve housing 26. A duct 26 provides communication between the valve housing 26 and the intake manifold of an internal combustion engine.

Referring now to Figure 2, the valve housing 26 is provided with an internal chamber 30 provided with an enlarged portion 32 with which the pipe 24 communicates. A guide rod 34 is positioned at its lower end in a recess 36 formed within the housing 26. A piston valve 38 is lodged within the chamber 30 of the valve. The upper end of the piston 38 is formed with an opening 40 through which the guide rod 34 extends. A spring 42 is positioned around the guide rod 34 and normally holds the piston valve 38 in a, position shown in Figure 2. The upper end of the housing 26 is closed by closure member 44, which is provided with a duct 46 communicating with the exterior appropriate connection opening into pipe 24 communicating with the crank case. In this manner any bleeding into the valve will be of atmosphere which it is desired to scavenge. The piston valve 88 is provided with a pair of ports 48 and 50. The port 48 is provided with an upper portion 52 and a. lower portion 54, as can readily be seen by reference to Figure 4.

In operation, the duct l2 communicates with the crank case of an internal combustion engine and" the "duct 28 communicates with the intake manifold thereof. The parts are assembled as shown in Figure 1 and the valve is in the position shown in Figure 2. As the internal combustion engine is started, the port II is closed as are the ports -48 and 52. Only the port 44 is open and its area is such as to preclude excessive increase in the manifold pressure. In other words, the

' area of the port 54 will permit a reduced ventiladu'ctiibn tha'topof'piston' will-move it downwardly against the action of spring 42, openin port 50 and port 48. This permits a fairly rapid flow of gases from the crank case through the filter. It will be observed that the gases are led to the interior of housing 8 above the filter 28. The carbon particles, sludge compounds and the like will be deposited in the filter and the filtered gases and vapors pass into the bowl 16. By this time, they are sufiiciently cool so they will condense, forming a pool of liquid IS in the bottom of the bowl i6. This pool can be observed through the transparent bowl. When the level of the liquid is sumciently high, the bowl is unscrewed and emptied. The change in direction of the gases in order to pass upwardly through the pipe 24 likewise helps in the separation of droplets of liquid. The filtered gases then pass into the chamber 32 and thence through ports 54, 48 and 5B, and outwardly through pipe 28 to the intake manifold of the engine. Th area of the ports is such as to provide a satisfactory control for normal operating speeds of the engine. If the piston 38 moves downwardly too much, thus permittin a greater flow of gases to the intake manifold, the partial vacuum is reduced to such an extent that the spring 42 will move the valve toward a position reducing the effective size of the ports. The volume of flow, therefore, within normal operating conditions is such as to maintain a flow of gases within predetermined limits. When the vacuum within the intake manifold becomes so great as to require the complete opening of ports 50 and 48, both the upper branch 52 and the lower branch 54 communicating with port 48 are effective. Any increase in partial vacuum in the intake manifold, after the full port openings are presented, cannot be compensated for. When this condition exists, there is the flow of gases into the intak manifold which will proceed at a rate too high for eillcient engine operation. There will be too great a dilution of the fuel mixture. Accordingly, we provide for the closing of the valve 38 when a. condition is reached which cannot be compensated for by the valve. It will be observed that as the valve moves downwardly, the lower branch 54 of the port 48 is first blocked oil. This is followed by the closing of ports 48 and 50. An

abutment 3i is formed at the bottom of the chamber 30. This abutment prevents the valve 34 from traveling further in a downward direction. In this position, only the upper branch 52 communicating with the port 48 is open and the reduced area insures against an excessive quantity permit the internal combustion engine to continue to operate. As the vacuum increases, the flow increases to a point of about three cubic feet per. minute. This fiow is sufiicient to efficiently scavenge the crank case of the internal combustion engine. An increase in the vacuum finds a sharp decrease in the rate of fiow. In the curve,

- great a variation in the flow of gases in response to an increase in vacuum.

It will be seen that we have accomplished the objects of our invention. We have provided apparatus for ventilating crank cases of internal combustion engines in which deleterious products of combustion which blow by the piston rings'are withdrawn from the crank case under the influence of the reduction of pressure existing in the intake manifold of the engine. We have provided means for controlling the fiow of gases out of the crank case such that excessive loss of vacuum is prevented at low vacuum conditions, and excessive dilution of the fuel mixture is prevented at conditions of high vacuum. Low vacuum conditions may exist, for example, not'only at starting times but also when increased loads are suddenly'placed upon the engine. At these times, it is especially important that bleeding of the vacuum be reduced as the reduced pressure is needed to provide fuel to the engine. If excessive bleeding takes place, the engine will stall. By introducing the products withdrawn from the crank case to a point above the filter, we insure that the transparent bowl is kept clear for observation.

It will be understood that'certain features and 2. Apparatus as in claim 1 in which said reservoir is formed of transparent material.

3. Apparatus as in claim 1 wherein said valve comprises a piston having a wall formed with a portfor controlling communication between said valve chamber and said intake manifold, said port being formed by an opening in the piston wall extending longitudinally of the axis of the piston, a closure for said valve housing, means for maintaining the top of said piston under atmospheric pressure, means for biasing said valve piston for abutment against said closure, means for limiting the movement of said valve piston away from said closure,-s'aid valve chamber being formed with portions adapted to cover an area of said port when said piston valve is either at the upper or lower limit of its travel, the length of said longitudinally extending port portion being such that a'lowersegment thereof is uncovered when the valve is in its upper position and another portion thereof is uncovered when the valve is in itslower position.

4. Apparatus as in claim 1 in which said valve is formed with a port, means for limiting the travel of said valve, means for biasing the valve toward one of said travel limiting means, means providing communication between the atmosphere and the other side of said valve whereby atmospheric pressure will tend to move said valve I against the action of said biasing means, said port being formed to expose a predetermined portion thereof at each travel limit position, means formed in said valve chamber for partially blockopening is presented, at high vacuum conditions sub-combinations are of utility and may be emanother predetermined port portion is presented" and at intermediate vacuum conditions, the port area varies as a function of the vacuum.

5. Apparatus as in claim 1 inwhich said valve comprises a housing formed with a longitudinally extending bore, a piston valve positioned in said bore for movement therein, a closure for said housing, means providing communication between the atmosphere and the top of said piston, said bore formed with an intermediate enlarged portion, said crank case conduit communicating with said enlarged portion, means'for biasing said details within the scope of the claims-without departing from the spirit of the invention. It 18. therefore, to be understood that this invention is not to be limited to the specific details shown and described. Having thus described our invention, we claim:

in said valve chamber adapted to control said communication.

piston to move upwardly for abutment against said closure, said means communicating with the intake manifold of an internal combustion engine being positioned below said piston, said pis ton being formed with a port, said port having portions extending longitudinally of the axis of said piston. means for limiting the downward movement of said piston, the length of said longiltudinally extending port portion being such that a predetermined area thereof will be unblocked when said piston is in abutment with said closure" and another predetermined portion thereof will be uncovered when said piston is positioned against said means for limiting its downward movement.

CLARENCE R. CALLAWAY. FRANK R. DUNN. I

No references cited.

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