US2884950A - Crankcase ventilator - Google Patents

Description

United States Patent l cRANKcAsE vENTILAToR Joseph J. Set'telmayer and James W. Wright, Chicago, lll., assignors, by mesne assignments, to Francois N. Palmatier, Chicago, Ill., as trustee Application October 10, 1955,`Serial No. 539,620

2 Claims. (Cl. 137-480) This invention relates to vacuum operated crankcase ventilators for use lwith piston type internal combustion engines such yas are commonly employed on trucks, busses and automobiles.

One lprincipal object of the present invention is to provide la new and improved crankcase Ventilator for connection between the crankcase and the intake manifold of an engine.

lt is a further object to provide a new and improved crankcase ventilator of the foregoing character which is adapted to withdraw vapors from the crankcase and deliver them to the intake manifold.

Another object is to provide a crankcase ventilatorl which is constructed in a new and improved manner so that it will be operative to ventilate the crankcase runder all conditions of engine operation, even when the vacuum inthe intake manifold is at a low level.

lt is a further object to provide a new and improved crankcase Ventilator which will ventilato the crankcase and deliver vapors to the intake ymanifold under conditions 'in which the vacuum in the intake manifold is low, as for example, when the engine is under a heavy load and the throttle is nearly or fully open.

lt is another object to provide a crankcase ventilator which affords increasingly restricted communication between the crankcase and the intake manifold with increasing vacuum in the manifold.

A further object is to provide a -crankcase ventilator which is effective in operation yet is simple in construction and low in cost.

Further objects and advantages 'of the invention will appear from the following description, taken with the accompanying drawings, in which:

Figure l is a side elevational view of an internal com bustion engine equipped with a crankcase ventilator ,constituting an illustrative embodiment of the invention.

yFig. 2 is a horizontal sectional view taken through the crankcase ventilator, generally along a line 2-2 in Fig. i.

Fig. 3 is avertical sectional view taken generally along a vlinef33 in Fig. 2.

If the drawings are considered in greater detail, it will -be seen that they illustrate a crankcase ventilator l0, shown in connection with a piston type internal combustion engine 12 such as might be `used on an automobile, truck, bus or other automotive vehicle. lt will be understood that the crankcase ventilator l may also be used in connection with farm tractors, industrial vehicles and equipment, and stationary engines.

The illustrated engine 12 comprises a crankcase le which normally contains a pool of oil 16. During engine operation, oil vapor, water vapor and vapors of the gasoline or other fuel tend to accumulatein the space above the oil pool 16 in the crankcase 14. The crankcase 14 is provided with an upwardly extending breather tube 18 which also may serve as a filler pipe for introducing oil into the crankcase.

Theengine 12 also is equipped with an intake manifold 20 which hdelivers combustion air tothe cylinders of the engine. rl`he illustrated engine l2 is of the type having a carburetor 22 for mixing fuel vapor with the air entering the intake manifold. It will 'be understood, however, that the invention is applicable to other types of engines, in which the fuel is introduced into the cylinders by means other than a carburetor, such as fuel injectors, for example.

The crankcase ventilator l0 is adapted to be connected between the crankcase 14 and the intake manifold 20 so that the vacuum existing in the intake manifold dur ing normal engine operation will suck vapors and air out of the crankcase and into the manifold- The combustible components of the vapors will be utilized as fuel in the engine, with the result that engine efficiency will be increased. At the same time, the crankcase will be ventilated to prevent undue accumulation of vapors, which might lead to corrosion, polution of the oil, and eventual deterioration of the engine. The oil vapor also sucked into the engine also tends to lubricate the upper portions of the engine cylinders.

ln the illustrated arrangement, a connection is made to the crankcase 14 by means of a conduit fitting 24 affording communication with the breather tube 18. A connection. is made to the intake manifold 20 by means of a fitting 2S mounted on the carburetor. Ordinarily, an intake manifold connection is provided on a carburetor for connection to windshield wipers or other devices to be operated by the vacuum in the intake manifold. The fitting 2S may be screwed into or otherwise mounted on this intake manifold connection on `the carburetor 22. Hoses 3l? and 32 or other lengths of tubing extend between the fittings 2li and 28 and the crankcase ventilator l0 so as to convey the crankcase vapors to and from the ventilator.

From Figs. 2 and 3 it will be seen that the illustrated crankcase ventilator l0 comprises a body 34; having inlet and outlet openings 36 and 38 which are internally threaded and thus are adapted to receive fittings 4@ and 12 at the ends of the hoses or conduits 3@ and 32. In this instance, the body 34 is lgenerally in the shape of a circular disk and the openings 36 and 38 are formed radially in the 'body at diametrically opposite points. An alternate inlet opening f4 is formed axially in the lower end of the body 34 4but is shown closed by a plug d6. A bracket 4S may be utilized to support the ventilator l@ on the engine l2. The illustrated plug 46 has a head 50 which is employed to clamp the bracket 4S to the underside of the body liti.

The arrangement of the crankcase ventilator l0 is such as to provide restricted communication between the inlet and outlet openings 36 and 33. A relatively small degree of restriction is provided at low vacuum levels. However, with increasing vacuum, the degree of restriction is increased to limit the amount of air drawn into the engine and thereby prevent the crankcase ventilator from causing an overly lean fuel-air mixture at high vacuum levels.

To perform these and other functions, the crankcase ventilator l0 might be arranged in various ways. However, in the illustrated construction, a housing 52 is mounted on the upper end of the body 34 to provide a charnber fi. Preferably, the housing 52 is made of a transparent material, such as glass or various plastics, in the form of an inverted bowl. ln this way the interior of the chamber 54 may be inspected readily. A clamp 55 is employed to hold the housing 52 on the body 34. Clamps of various tvpes might be employed, but the illustrated clamp comprises a bail Sii having its lower ends pivoted on the body 345. A thumb nut is threadedly received on a depending screw 62 having its upper end welded or otherwise secured to the top of the bail 58. A bell-shaped clamping foot 64 is received on the lower end of the screw 62 and is adapted to be pressed against the top of the housing S2 by the thumb nut 60. It will be seen that a recess 66 is formed in the top of the housing 52 to locate the bell-shaped foot 64.

At the top of the body 34, an annular seat 68 is formed to receive a ring-shaped gasket 70 which is interposed between the body and the lower edge of the bell-shaped housing 52. The gasket 70 forms an air-tight seal between the housing 52 and the body 34.

Restricted communication between the inlet and outlet openings 36 and 38 might be provided in various ways. However, in the illustrated construction, such communication is afforded by upper and lower ports or orifices 72 and 74 formed in a tubular guide 76 which extends upwardly from the body 34 into the chamber 54. The guide 76 has a reduced lower end portion 7S mounted in an axial bore 80 which extends upwardly in the body 34 from the alternate inlet opening 44. The reduced end portion 78 is press-fitted into the bore 80 or otherwise retained therein. A passage 82 extends between the lateral linlet opening 36 and the bore 80. Within the hollow tubular guide 76 is a bore or opening 84 which is in communication with the inlet opening 36 through the passages 80 and 82.

It will be seen that the body of the guide is n the form of a hollow substantially cylindrical wall 86. The orifices 72 and 74 extend radially through the wall 86. In the illustrated construction, there are two upper orifices 72 at diametrically opposite points in the wall 86, while only a single lower orifice 74 is provided. The two upper orifices 72 are connected together by an external annular groove 88 formed in the guide 76. It is preferred that the effective area of the lower orifice 74 be substantially less than the total effective area of the upper orifices 72, as shown.

It will be seen that a passage 90 is formed in the body 34 so as to afford communication between the outlet opening 38 and the chamber 54. Thus, the intake manifold vacuum is applied to the interior of the chamber 54. Various means might be employed to regulate communication through the orifices 72 and 74 between the inlet and outlet openings. However, the illustrated crankcase ventilator utilizes a weight 92 for this purpose. It will -be seen that the weight is generaly cylindrical in form and is provided with a bore 94 adapted to be slidably received over the guide 76. The bore 94 is open at its lower end but is closed at its upper end 4by a top wall portion 96 of the weight 92. The weight also has a hollow cylindrical side wall portion 98. The sliding fit between the bore 94 and the guide 76 is sufiiciently close to prevent any substantial leakage of air between the guide and the weight 92.

When the engine 12 is not in operation or when the vacuum in the intake manifold is extremely low, the weight 92 is in its lowermost position with the top wall portion 96 of the weight engaging the top of the guide 76. In this position of the weight, the side wall portion 98 extends downwardly along the guide 76 to cover the lower orifice 74. 'llhe upper orifices 72 would also be covered were it not for a port 100 extending through the side wall 9S of the weight at such an elevation as to register with the annular groove 88 when the weight is in its lowermost position. Thus, the orifices 72, the groove 88 and the port 100, acting in series, provide limited communication between the inlet and outlet openings 36 and 38 when the weight 92 is in its lowermost position. The weight w'ill remain in this position for low values of vacuum, such as may be present in the intake manifold when the engine is puling hard with the throttle nearly or completely open. Under such conditions, vapors and air will be sucked from the crankcase 14 through the orices 72 and the port 100 into the chamber 54. Any particles of dust or grit and any larger droplets of oil will tend to be deposited in the chamber S4 so that they will not pass on through the outlet opening 38 to the intake manifold 20. From time to time, the housing 52 may be removed for the purpose of cleaning out the accumulated dirt and oil, which will be visible through the transparent wall of the housing.

With increasing vacuum in the intake manifold 20, the pressure differential between the inside of the guide 76 and the chamber 54 will become sufficient to raise the weight 92 on the guide 76. Upward movement of the weight 92 is limited by engagement -between the weight and the housing 52. Thus the weight will occupy the position shown in dotted lines in Fig. 3 when the weight is fully raised. In this position of the weight 92, the lower orifice 74 is uncovered while the upper orifices 72 and the groove 88 are covered by the side wall 98 of the weight. The port is out of registration with the groove 88 when the weight is raised. Thus, the orifice 74 provides the sole means of communication between the crankcase and the intake manifold when the vacuum in the intake manifold is relatively high. It is preferred that the effective area of the lower orifice 74 be less than that of the upper orifices 72 so that the communication between the crankcase and the intake manifold will become more restricted with increasing vacuum. In this way, the crankcase ventilator will be effective to ventilate the crankcase but will not cause an overly lean fuel-air mixture. The orifice 74 limits the amount of air drawn from the crankcase into the intake manifold at high vacuum levels and thereby prevents the introduction of an excessive amount of air into the intake manifold.

While the weight 92 may be made to rise at any desired vacuum level, it has been found practicable to proportion the weight so that it will rise at a vacuum of 8 or 9 inches. With this adjustment, it will be typical for the weight to be in its raised position with the engine idling or operating at light loads, inasmuch as intake vacuum levels of 17 to 20 inches are usually present under such conditions. When the engine is pulling hard with the throttle nearly or completely open, the vacuum may drop to levels as low as 2 to 4 inches, in which case the weight 92 will drop to its lowermost position to decrease the amount of restriction in the communication afforded between the crankcase and the intake manifold and thereby insure adequate crankcase ventilation. This is important inasmuch as the development of vapors in the crankcase is often at a maximum when the engine is pulling hard.

Thus, the crankcase ventilator 10 provides effective crankcase ventilation and utilization of crankcase vapors under all conditions of engine operation. For low levels of Vacuum in the intake manifold, the weight 92 uncovers the large upper ports 72 and thereby provides relatively free communication between the crankcase and the intake manifold. With increasing vacuum, the weight 92 rises and covers the ports 72 to increase the degree of restriction between the crankcase and the intake manifold. The smaller lower port 74 is uncovered with the weight raised so that restricted communication will still be provided between the crankcase and the intake manifold.

It will be seen that the illustrated crankcase ventilator is effective and rugged in construction. Nevertheless, it is simple and may be produced at low cost. In use, it will provide improved engine operation.

Various modifications, alternative constructions and equivalents may be provided without departing from the true spirit and scope of the invention, as exemplified in the foregoing description and defined in the following claims.

We claim:

l. In a crankcase ventilator, the combination comprising a body, an inverted bowl-shaped housing mounted on said body and defining a chamber between said housing and said body, means disengageably holding said housing on said body, said body having inlet and outlet openings therein to receive and discharge crankcase vapors, a hollow tubular guide extending upwardly from said body and having its interior connected to said inlet opening, a passage in said body connecting said outlet opening to said chamber, a weight having a bore therein opening downwardly and closed upwardly, said weight being mounted with said bore slidably received over said guide, said guide having upper and lower vertically spaced ports extending therethrough, said weight being movable vertically on said guide between a lower position with said weight covering said lower port and an upper position with said weight uncovering said lower port, said weight being biased by gravity toward said lower position and being movable into said upper position by increasing vacuum in said outlet opening, said guide having an external annular groove extending therearound in alignment with said upper port, said weight having a port extending therethrough outwardly from said bore and registering with said upper port and said annular groove with vsaid weight in said lower position, said weight covering said annular groove with said weight in said upper position, said lower port being smaller in eiective size than said upper port to aord increased restriction of communication between said inlet and outlet openings with increasing vacuum in said outlet open- 2. In a crankcase ventilator, the combination comprising a body, a housing mounted on said body and dening a chamber between said housing and said body, means disengageably holding said housing on said body, said body having inlet and outlet openings therein to receive and discharge crankcase vapors, a hollow tubular guide extending upwardly into said housing from said body and having its interior connected to said inlet opening, a passage in said body connecting said outlet opening to said chamber, a weight having a bore therein opening downwardly and closed upwardly, said weight.

being mounted with said bore slidably received over said guide, said guide having upper and lower vertically spaced ports extending therethrough, said weight being movable vertically on said guide between a lower position with said weight covering said lower port and an upper position with said weight uncovering said lower port, said References Cited in the file of this patent UNITED STATES PATENTS 367,324 Shields July 26, 1887 2,069,022 Sisk Ian. 26, 1937 2,240,459 McDowell Apr. 29, 1941 2,358,875 Nichols Sept. 26, 1944 2,359,485 Lowther Oct. 3, 1944 2,633,113 McCarty Mar. 31, 1953 2,716,398 McMullen Aug. 30, 1955 2,742,057 Krieck Apr. 17, 1956 2,800,919 Kates July 30, 1957

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