US3766898A

US3766898A - Crankcase ventilation valve

Info

Publication number: US3766898A
Application number: US00191524A
Authority: US
Inventors: Mullen W Mc
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1971-10-21
Filing date: 1971-10-21
Publication date: 1973-10-23
Anticipated expiration: 1990-10-23
Also published as: GB1381137A; JPS4850128A; AU4710072A; AU446508B2; DE2249802A1; DE2249802C3; DE2249802B2; JPS5214811B2; CA956531A

Abstract

A crankcase ventilation valve for an internal combustion engine has an undercut portion of the plunger body which acts as a deposit storage area for adherent deposits scraped from the flow control portion of the plunger body through its reciprocating movement in the flow control orifice. The undercut portion is located on the plunger body so that the closest end thereof enters but does not pass through the flow control orifice when the plunger is in its extreme position against its stop. In this way positive scraping of deposits into the storage area is assured without substantial effect on the valve flow curve being caused by the presence of the undercut storage area.

Description

Lowther 123 1191;

1 1 Umted States Patent 1191 1111 McMullen 1 1 11 Oct. 23, 1973 CRANKCASE VENTILATION VALVE [75] Inventor: Wesley W. McMullen, Flint, Mich. Pmfmry Exam"1er Al FawremFe sm'th 1 Assistant Exammer-Mwhael Koczo, Jr. [73] Assignee: General Motors Corporation, A r -J, L, Carpenter et a]. Detroit, Mich.

V [22] Filed: Oct. 21, 1971 57 ABSTRACT [21] PP 191,524 A crankcase ventilation valve for an'internal combustion engine has an undercut portion of the plunger 52 u.s. c1. 123/119 B, 137/480 body which acts as a deposit Storage r for adherent [51] Int. Cl. F02d 9/00 deposits scraped from the flow Control Portion of the [58] Field of Search 123/119 B; 137/480 P n body/through its reciprocating movement in theflow control orifice. The undercut portion is lo- 5 References Cited cated on the plunger body so that the closest end UNITED STATES PATENTS thereof enters but does not pass through the flow control orifice when the plunger is in its extreme position 3,165,097 1/1965 Lowther 123/119 B against its Stop- In i y positive p g of p 3,263,699 8/1966 Glvler et al. 123/119 B X 3 709 204 [1973 No one 123/1119 B 1ts 1nto the storage area 1s assured w1thout substantlal 3'645242 2/1972 Hofiuchi." 137/48OiX effect on the valve flow curve being caused by the 3,359,960 12/1967 Pittsley.... "123/1198 Presence of the undercut Storage 3,354,898 11 1967 B 123 119 B UX arnes 3 Clalms, 4 Drawmg Figures CRANKCASE VENTILATION VALVE BACKGROUND OF THE INVENTION This invention relates to crankcase ventilation flow control valves for internal combustion engines and, more particularly, to a crankcase ventilation valve for controlling the flow of vapors into the induction system from the crankcase or other comparable portion of the housing of an internal combustion engine.

It is old in the art to provide'an internal combustion engine with a so-calledcrankcase ventilation system, which includes means for recirculating blow-by gases and other vapors from the crankcase 'or comparable portion of an internal combustion engine to its induction system. Commonly, such systems are now closed by providing means for drawing fresh air into the crankcase from the engine air cleaner or other portion of the induction system ahead of the carburetor so as to substantially prevent the escape" of crankcase vapors, blow-by gases and the like to the exterior of the engine under all operating conditions.

The majority of crankcase ventilation systems currently in use in automotive vehicles include the provision of a flow control valve, called a crankcase ventilationvalve or PCV valve, in the conduit between the engine crankcase and the engineinlet manifold or connecting portion of the induction system to control the rate of flow of blowby gases and other vapors into the engine induction system.

One type of valve which has been extensively used in commercial vehicles in the disclosed or a modified form is shown in U.S. Pat. No. 3,359,960 Pittsley, which was granted Dec. 26, 1967 to the assignee of the present invention. As indicated in the Pittsley patent, valves of the typedisclosed therein include stop means which are engageable by the head of the plunger so as to prevent a portion of the plunger adjacent the head from entering the flow control orifice. This portion of the plunger then acts as .a dirt storage area and retains out of the flow stream some of the deposits which are scraped from the plunger flow control surface.

While the operation of such valves has been highly satisfactory, it hasbeen found that under engine operating conditions which cause an excessive rate of de posit formation 'on the crankcase ventilation valve plunger, the build-up of depositsin the dirt storage area may become excessive so that it changes the flow characteristics of the valve, primarily by reducingthe flow capacity at or near the engine idle position of the plunger. This flow reduction, if excessive, may affect engine operation by requiring'adjustments to the carburetor settings, as well as interfere with proper ventilation of the engine crankcase. As a result, replacement of the crankcase ventilation valve may be required.

SUMMARY OF THE INVENTION the plunger is against its stop, is' located within the flow control orifice. This point is arranged to enter but not pass through the orifice. By this construction, deposits are scraped in positive fashion from the flow control portion of the plunger body into the undercut deposit storage portion but this portion is prevented from having any significant effect upon the flow characteristics of the valve.

These and other features of the invention will be more apparent from the following description and drawing which disclose one embodiment of flow control valve formed according to the invention.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a front elevational view of an engine having a crankcase ventilation system including a flow control DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing in detail, FIG. 1 illustrates an internal combustion engine generally indicated by numeral 10 and having a plurality of cylinders 12 arranged in a pair of banks angularly displaced with respect to one another. Cylinders: 12 are open at their lower portions to the engine crankcase 14 which is defined by the exterior walls of the engine and by an oil pan 16. Within cylinders. 12 are pistons 20 arranged for reciprocation therein and connected by connecting rods 22 with the respective throws of crankshaft 24.

The engine includes cylinder heads 26 closing the tops of the cylinders in conventional manner and forming in cooperation with the pistons combustion chambers 28. An induction system is providedfor introducing a combustible mixture into the combustion chamhers and includes inlet ports 30 formed in the cylinder heads, an 'inlet manifold 32 connecting with the inlet ports, a carburetor 34 mounted on the inlet manifold and an inlet air cleaner 36 carried by the carburetor.

Engine 10 further includes a crankcase ventilation systemhaving an inlet conduit 38 which connects the engine air cleaner 36 with the interior of one of the en-- gine rocker covers 40. The interior of rocker cover 40.

communicates through passages, not shown, with the engine crankcase 14 which, in turn, communicates through additional internal passages with the other engine rocker cover 42.-A crankcase ventilation flow control valve 44 is mounted in rocker cover 42 and connects through an outlet conduit 46 with the inlet manifold 32 of the engine. FIGS. 2 4 disclose in detail the construction of the crankcase ventilation flow control valve 44 of FIG. 1. Valve 44 is shown to include a multi -piece housing 48 which is made up of a tubular body member 50 formed of sheet metal and secured by crimping at 52 to a formed outlet member 54. Member 54 includes an integral outlet fitting 56 over which conduit 46 is resiliently retained. The member 54 also retains, in an enlarge'd portion adjacent fitting 56, an annular insert 58 which includes a flow control orifice 60 anda longitudinally extending annular stop portion 62. A backfire washer 64 is received in the end of member 50 opposite from the insert 58 and includes a central opening 66. The portion of housing 48 adjacent the backfire washer 64 is received within a rubber grommet 68 secured within the rocker cover 42 so as to provide for receiving crankcase vapors, including engine blowby gases, from the interior of the engine crankcase to pass through the opening 66 and orifice 60 of the valve housing and into the engine induction system.

Within housing 48 there is reciprocably located a valve element or plunger 70. Plunger 70 includes an elongated bodyportion 72 connecting with an enlarged head portion 74 which extends radially beyond the body portion into rubbing contact with the walls of the housing 48. The head portion is provided with a plurality of cutouts 76 to' permit a flow of crankcase vapors past the head at all times except when the head is seated against the backfire washer 64 in which condi-' tion it closes the opening 66. The plunger body is made up of a generallytapereld fiow control portion 78 which extends to the end of the plunger opposite from head 74 and a deep square-edged undercut deposit storage portion 80 extending between the head 74 and the flow control portion 78. Flow control portion 78 tapers generally from its smaller end to its larger end and is free to rub against the orifice 60 during movement therein. The smaller end of portion 78 is positioned within orifree 60 when the'head portion 74 is against the backfire washer 64 and the larger end is positioned within orifice 60 when the head portion 74 is against the stop 62. A coil spring 84 is provided which extends between the insert member 58 and the underside of head portion 74 and acts to bias the plunger 70 downwardly, as shown in the drawing, in a direction to permit increased flow through the orifice 60'. g

In operation, the vacuum created in the engine inlet manifold 32 causes a reduction in pressure in the conduit 46 and outlet fitting 56 downstream of the orifice 60. This creates a flow of crankcase vapors through the valve 44, the amount of which is controlled by the position of the valve plunger 70. When the difference in pressure across the plunger is high, as when the engine is idling and inlet manifold vacuum is high, plunger 70 is urged upwardly against the force of spring 84 to a position at or near that shown in FIG. 3 of the drawing.

' In most instances the valve will be sized so that the plunger head 74 is close to but not against the stop 62 when the engine is idling but will contact the stop as shown in FIG. 3 during the highervacuurn conditions which exist during engine deceleration. In the position shown in FIG. 3, the maximum diameter of the plunger control portion 72 is within the orifice 60 so that a maximum restriction to flow exists and the passage of crankcase vapors is limited accordingly.

It should be noted that the undercut deposit storage portion 80 is arranged so that one end thereof also extends within the orifice 60 when the plunger head is against stop 62. In this way, deposits, which may collect upon the control surfaces of portion 72 from the crankcase vapors which flow over its surface, will be scraped off by rubbing action of portion 72 against the inner diameter of orifice 60 and deposited within the storage portion 80. In this way, adherent deposits are moved inwardly to the smaller diameter portion of the plunger so that they do not block the flow of crankcase vapors when the plunger is at or near the idle position. In addition, the fact that the deposit storage area is made so as not to extend completely through the orifice at any time prevents this portion from having any significant effect upon the rate of flow through the orifice which is instead controlled by the adjacent larger diameter end of the flow control portion 72.

The term crankcase ventilation valve is used herein as it is a common identifying term for such valves and is not intended to indicate any limitation on their use which, it should be understood, may include application in engines which have no crankcase or in other engine systems.

While the-invention has been described by reference to a preferred embodiment, it should be apparent that various changes could be made within the scope of the inventive concepts taught and, accordingly, the invention is intended to be limited only by the language of the following claims.

I claim:

1. A flow control valve for use with an internal combustion engine to control the flow of blow-by gases or the like to the engine induction system, said valve comprising a housing defining a fluid flow path and having a flow control orifice in said flow, path,

a valve plunger within said housing, said plunger having an elongated body including a flow control portion of variable cross sectional area longitudinally thereof, which is reciprocably movable within said orifice in response to pressure differentials across the valve plunger to control fluid flow through the orifice, and

stop means in the housing and engagable by the valve plunger only at one predetermined position thereof to stop movement of the valve plunger in one direction at said predetermined position within said orifice,

said valve plunger body having an undercut portion adjacent the flow control portion, said undercut portion being positioned so that one end thereof extends into but does not pass through the orifice when said valve plunger is against said stop means, whereby said undercut portion forms a storage volume for adherent deposits scraped from the surface of the plunger body flow control portion during its movement within the orifice.

2. A crankcase ventilation valve for use with an internal combustion engine to control the flow of blow-by beyond said predetermined position in one direction,

said deposit collection portion being formed by a substantial undercut of the elongated portion, said deposit collection portionextending from adjacent the head to a point, on the body portion which enters but does not pass through the orifice when the head moves into engagement with the stop means.

3. A crankcase ventilation valve for use with an internal combustion engine to control the flow of blow-by gases and vapors into the engine induction system, said valve comprising a housing having a fluid flow control orifice therein, a valve plunger reciprocably carried in said housing and having an elongated body portion and a head at one end thereof, said body portion including a sharp-edged undercut forming a deposit collection portion adjacent the head and a generally tapered flow control portion having a larger diameter, endthe end of said larger diameter portion adjacent said undercut is within said orifice to provide a maximum flow restriction, and

spring means in said housing and biasing said plunger in a flow increasing direction away from said stop means.

Claims

1. A flow control valve for use with an internal combustion engine to control the flow of blow-by gases or the like to the engine induction system, said valve comprising a housing defining a fluid flow path and having a flow control orifice in said flow path, a valve plunger within said housing, said plunger having an elongated body including a flow control portion of variable cross sectional area longitudinally thereof, which is reciprocably movable within said orifice in response to pressure differentials across the valve plunger to control fluid flow through the orifice, and stop means in the housing and engagable by the valve plunger only at one predetermined position thereof to stop movement of the valve plunger in one direction at said predetermined position within said orifice, said valve plunger body having an undercut portion adjacent the flow control portion, said undercut portion being positioned so that one end thereof extends into but does not pass through the orifice when said valve plunger is against said stop means, whereby said undercut portion forms a storage volume for adherent deposits scraped from the surface of the plunger body flow control portion during its movement within the orifice.

2. A crankcase ventilation valve for use with an internal combustion engine to control the flow of blow-by gases and vapors into the engine induction system, said valve comprising a housing having an orifice therein to restrict fluid flow therethrough, a valve element in said housing and having an elongated body portion and a head at one end thereof, said body portion including a deposit collection portion adjacent the head and a generally tapering flow control portion on the end opposite the head, and stop means in the housing and engagable by the head only at one predetermined position of the valve element to prevent movement of the valve element beyond said predetermined position in one direction, said deposit collection portion being formed by a substantial undercut of the elongated portion, said deposit collection portion extending from adjacent the head to a point on the body portion which enters but does not pass through the orifice when the head moves into engagement with the stop means.

3. A crankcase ventilation valve for use with an internal combustion engine to control the flow of blow-by gases and vapors into the engine induction system, said valve comprising a housing having a fluid flow control orifice therein, a valve plunger reciprocably carried in said housing and having an elongated body portion and a head at one end thereof, said body portion including a sharp-edged undercut forming a deposit collection portion adjacent the head and a generally tapered flow control portion having a larger diameter, ending immediately adjacent the deposit collection portion, and a smaller diameter at its end opposite from the head, said flow control portion being free to rub the edges of said orifice during reciprocation therein, stop means in the housing and engagable by the head in only one predetermined position of the plunger to prevent movement of the plunger in one direction beyond said predetermined position wherein the end of said larger diameter portion adjacent said undercut is within said orifice to provide a maximum flow restriction, and spring means in sAid housing and biasing said plunger in a flow increasing direction away from said stop means.