US3189012A

US3189012A - Crankcase ventilation system

Info

Publication number: US3189012A
Application number: US339391A
Authority: US
Inventors: John W Humphreys
Original assignee: Johnson Products Inc
Current assignee: Johnson Products Inc
Priority date: 1964-01-22
Filing date: 1964-01-22
Publication date: 1965-06-15
Anticipated expiration: 1982-06-15
Also published as: DE1997141U; GB1069136A

Description

June 15, 1965 J. w. HuMPHREYs CRANKCASE VENTILATION SYSTEM Filed Jan. 22, 1964 FIG.I

INVENTOR. Jay/V zd. #0MM/kfw FIG. 4

' atmosphere.

United States Patent O 3,189,012 CRANKCASE VENTlLATION SYSTEM John W. Humphreys, Muskegon, Mich., assignor t Johnson Products, Inc., Muskegon, Mich., a corporation of Michigan Filed Jan. 22, 1964, Sor. No. 339,391 Claims. (Ci. 123-119) This invention relates to a crankcase ventilation system, and more particularly to a unique crankcase air inlet valve in combination with a positive pressure crankcase exhaust control system to the intake manifold.

This invention relates to my prior invention in Patent No. 3,108,581, assigned to the assignee herein.

My prior invention, disclosed and claimed in the above identied patent, utilizes a sealed crankcase exhausting system to the intake manifold. A ow control valve is in the connecting conduit. lt allows tiow of blow-by gases from the crankcase to the manifold when opened by a control element exposed on one side to atmospheric or other standard pressure and on the other side to positive crankcase pressure. Thus, it opens in response to the excess of crankcase pressure over atmospheric pressure to exhaust blow-by gases to the manifold. No gases are allowed to ow out of the sealed crankcase to the atmosphere. Also, the usual substantial air intake directly from the atmosphere to the crankcase is eliminated, to thereby control sludging due to cold air flow and dust into the crankcase.

Extensive testing and use of the patented system on vehicles of various types has proven its uniqueness, operativeness, and advantages. However, recent testing and use of the system on engines of road-type vehicles having engines at least partially worn, has shown the necessity of 'a modification of the system for optimum performance under these conditions.

It has been found that worn engines employing the novel system on a sealed crankcase experience a substantial crankcase vacuum or negative pressure when the vehicle is decelerating under closed throttle conditions. Closed throttle deceleration typically occurs when a vehicle is using the engine as a braking force, for example, when going down a long hill. The vacuum is caused by the continued reverse flow of gases from the crankcase through the engine cylinders around the pistons to the combustion chambers, instead of vice versa.

This phenomenon and its result can be explained as follows: An engine is normally operating as an air pump. Air is pumped through the carburetor and induction system by the downward motion of the piston. During this time, the intake valve is open. The intake valve is then closed and the air mixed with fuel from the carburetor) is compressed by the upward motion of the piston. The charge is then red by the spark plug,

pushing the piston downward for the power stroke. The

exhaust valve is opened after the power stroke and the piston returns to the upward position, pushing the burned exhaust gases into the exhaust manifold and out to the The amount of air being pumped through the engine depends on the position of the carburetor throttle plate. During deceleration, with t-he throttle plate closed, practically no air is pumped through the engine because of the restriction at the carburetor. The pumping eifort, however, is being continued by the pistons. The result is that a high vacuum (up to 26 Hg) is created in the intake manifold. During the intake stroke of the piston, this vacuum is also present in the combustion chamber and the combustion cycle produces relatively little pressure rise in the combustion chamber. Since the average combustion chamber pressures during deceleration are well below atmospheric pressure, crankcase gases are drawn past the piston rings into the comice bustion chamber, and past the intake valve-to-valve guide clearance into the intake manifold. As an engine wears, the amount of gases drawn from the crankcase during deceleration increases, which reduces crankcase pressures below atmospheric pressure to such an extent as to be detrimental.

It is an object of this invention to provide a pressure operated crankcase ventilation system as useful for worn engines of road vehicles as engines in good condition, by providing a crankcase ventilation cap that prevents any crankcase exhaust flow to the atmosphere, but also prevents any substantial vacuum or negative pressure from forming in the crankcase.

It is another object of this invention to provide an internal combustion with controlled gaseous flow and complete pressure control between the intake manifold, the crankcase7 and the atmosphere, to effect optimum oper ating conditions with minimum sludge formation in the crankcase and no exhausting of noxious fumes from the crankcase to the atmosphere.

Still another object of this invention is to provide a crankcase ventilation system useful for any internal combustion engine without adjustments or modifications to suit the particular engine, and which remains highly effective to control gaseous flow in worn engines of road vehicles.

A further object of this invention is to provide a crankcase exhaust control system that prevents exhaust outflow to the atmosphere and admits small controlled amounts of air to the crankcase from the atmosphere just sufficient Ito prevent detrimental excess vacuum but small enough to limit sludging to an insignificant amount.

Another object of this invention is to provide a crankcase ventilation system especially useful for worn engines lthat are subjected to closed throttle deceleration.

Another object of this invention is to provide a novel crankcase liller tube cap with the capacity of controlling atmospheric air intake into a sealed crankcase in regulated small quantities to prevent substantial crankcase vacuum, by effecting one-way ow control to the crankcase, and preventing exhausting of noxious fumes to the atmosphere while allowing limited inux of atmospheric air with minimum sludging.

These and several other objects of this invention will become apparent upon studying the following specification in conjunction with the drawings in which:

FIG. l is an end elevational view of an engine of this inventive combination;

FIG. 2 is a side elevational view of the novel oil filler tube cap forming part of this system;

FIG. 3 is a sectional view of the cap in FIG. 2; and

FIG. 4 is a sectional elevational view of the pressure ow control part of the novel system.

The novel system 10 illustrated in FIG. 1 includes an internal combustion engine 12 having a crankcase 14, an intake manifold 16, and an oil pan 18, and a filler tube 20. The system includes gaseous Vapor flow control means 2.2 from crankcase 14 to intake manifold 16, and includes crankcase vacuum relief means 24 in the rform of an oil filler cap on filler tube 2i).

The ow control cap -24 is formed of a housing shell 26, having a recessed area 28 to tit over the iiller tube 20. The lower peripheral edge of the housing includes a planar, annular retention groove 30 receiving and retaining an annular resilient ring 32 preferably of a resilient rubber material to retain the cap on the filler tube by friction, and to seal the connection.

An annular dividing partition 34 extends across the central portion of the housing between its ends. It includes a central depression 36 forming a spring seat 37. The depression has an axial control opening 38 within the peripheral spring seat. The cross section of any Ytheperipheral inner wall `of housing 25.) The pocket of the U receives an annularresilientstop 40ct rubber for abutment of the upper end of the filler tube Y2.1i'. An Y upper annular valve seat 42 rests upon and is secured to the Vparti-tion'lid.4 g

An annular filter Y44 is positioned inthe upper halfrof Vthecap between the upper end andjthe partition. I t is .between thecentrgalkv passageway` portion of the cap and a v plurality of atmospheric inlet ports 46.l `Consequently, a passageway meansis'forrned from ports 46 through posits on the butterfly valve .tend to be washedoli by the Y to the engine... ThereforeLto relieve thisV condition, when the pressure diterential between the atmospheric standard pressure land the negative crankcasekpressure or vacuum becomes a predetermined amount, "the pressurejdifferf ential Yshifts the plate check valve-4`8 against the bias of valve port 47, through depression portand cavity Y28 l to the fillery tube. ,This passageway and more specifically valve port 47, is normally closed lbyna plate type, oneway check valve 48.vbiased; byman 1annular compression springrSlOagainst Yvalve seat` 42. j The biasingforce of this springfis calculated to cause the valve Vto open only with Ia predetermined pressure differential between atmospheric air at ports/46v and a negativer crankcase presf morebspeifcally V totlrie intake manifold 16,-is achieved with ow control mechanismY 22.. .y

:This `flow controlY mechanism includes a conduit-formed by connector 60, rubber hose 62 between this connector ynector.ttfbetweenthe central` portion Y64 and an outliow conduit 68` from `the side pan .'20 of` the engine block. Preferably, `an oilsepaprator 72 is attachedv tothe inside of the side pan toy lprevent 'n oil flow uptheconduit system.

g A buttery valve-76 is mountedon ja pivot axis Y'Z8 in the central portion V64` to close Voi` the Vpassage when' closed, and allowgaseous owrfrom the crankcase to thev intake manifold whenropenedfvary'ing .amountsa Ay pivotv link 8*,0 is'afxed to' shaft 78 externally of conduit section 64'. The upper end of `this/link 80 is pivotally attached y toa cross .reeiprocable 1ink782, the other endof which is aixed -to` retentionA plates 84' on OplDOsite sides of diaphragm' y'actuator' 86. This diaphragm 86 isY generally l circular in' configuration 'with link-.82 attached vto. the center thereof; Thelperiphery' of the/diaphragmA isf retained between two halves 9i) and 92 of'a pressure control housing. This pressure control housing has one side Vor chamberreriposed to atmospheric :pressure through ports 94, and theother vside vexposed to crankcase. pressureV through'k a crankcase pressure sensing Stube 96. This tube extends from this chamber down to Vtube portion64 onv the crankcase sideof'buttery valve`76. v

In operation, check valve`48i in the liller cap is normally. biased to a 'closed position.V operating :conditinsfblwaby occurs `from the cylinders sure'v above' atmospheric.

phragm 86 overthe atmospheric norm or standard, to shift the diaphragm. This shiftsthe link-agegto rotate the bu-ttery. valve a proportionate amountandrjallow crankcase jgaseous flow past the valve into the intake,

manifold. .As soon as the. .pressure differential disappears the lvalve is closed. lThe butterfly valve itselflis 'not responsive to a pressure diiferential between the intake 'manifold andthe crankcase.

Itis not opened by manifold va-cuum. Rather. the pressure responsive means or diaphragmr 86 which controls the valve, opens None ofthe crankcasefvapors moveinto Undernormal4 engine Y of the engine past the'pistons to increase crankcase pres- The crankcase pressure in the conduit creates apositive pressure diiferential on diaspringk Thisv allows fent'ry off a small controlled amount of filteredA atmospheric air into the crankcase to eliminate*A `this differential. It will bezr'ealized that the amount ofair necessaryl'tofrelieve the. vacuum'` is normally insignificant so' that sludging. caused yby'e'nt-r'y of cold air into the crankcase will not be ,a problem..A

Therefore, nofmatter whatthe condition of the engine .or the conditions of operation, the gaseous pressure conditions and ow .are completely controlled throughout the crankcase and intake manifold system of the engine, to maintainfat at optimum. performing conditions. lCold air entry into'th'e crankcase is Akept-atfa minimum. The crankcase .is sealed 'to prevent vexhausting Aof noxious fumes to the atmosphere.

Additionall objectsA of this -inventionfwillfoccur to those skilled in the art upon studying the foregoing form of this invention and the principles involved.` Also 'it is conceivable that certainstructural modifications can be made in'thesystein described -or in the valvingfmechanism withy out departingfrom the inventivexconcept taught., Therefore, this invention isvntto be limited to the particular details of the prefr'redffor'm'illustrated,fbut.only by the scope of the appendedgclaims and the Areasonably equivalent structures to those dettined therein.

Ivclaim: f K f. g Y K i1. An. engine ,assembly comprising: an internalV combustion engine including a sealed crankcase and intake manifold means; conduit vmeans extending-from said sealed crankcaseto said intake vmanifold' means; gaseous iiow regulator means for said conduit including a valving means anda vpressure responsive. element operatively associated with saidvalving'm'eans to open and close it;.said pressure Y responsive-elementbeing responsive to the pressure differential between positive crankcase pressure over a standard pres-sure ,to'open said valving'means and allow tlow of gases from said lcrankcase to` said intake'manifold upon an increase in crankcase'pressure over said standard pressure and `causing said valving means to close upon a decrease 'of crankcase pressure to said standard pressure; and a oneway normally closed Y valve bet-Ween said crankcase and the surroundingatmospheresubjecty to opening upon Y av decrease in crankcase pressure a'predetermined amount below afmsplieric pre'ssure't'o lopen and admita small Vquantity of atmospheric air to said crankcase until crank- 1v' case pressure increasesabovesaid predetermined amount.

'Y 2. An engine assembly comprising: an internal combustion engine including asealed crankcase and intake mani- :fold "'r'neansgrconduit means eritendin'gV from said sealed crai'ikoasey to saidintakemanifoldmeansg gaseous flow regulator means for said conduit including a'valving means v and a pressure responsive element operativelyyassociated .with saidvalvingrnieans to open and'close it; said pressure responsive,elementfbeingresponsive to thel pressure dif- I' ferential between positive crank-case pressure over aV standard-pressureJt-o open'said vali/ingv means and allow-flow of gases from'said cran-lecase to said intake mani-foldupon an increasein crankcase pressure over said standard pressure, and responsive to close said valving'meansupon a decrease in crankcase pressure below'saidst'andard pressure; a r'one-.way {normally-closed liow'control valving means'between said crankcase and agaseous supply'means,

preventingfoutllow `ofgases from said ycrankcase to the 5 atmosphere and responsive to open with a decrease of crankcase pressure below a predetermined minimum to allow gaseous inow to increase said crankcase pressure above said minimum.

3. An engine assembly comprising: an internal combustion engine including an intake manifold and a sealed cr'ankcase; a gas conduit between said manifold and crankcase; crankcase pressure responsive ilow control valvng means for said conduit for blow-by gases from said crankcase to said manifold; said tlow control valving means being substantially responsive only to positive crankcase pressures over a standard pressure; and negative pressure relief means for said crank-case to relieve negative pressure occurring in said crankcase more than a predetermined value with respect to a standard pressure.

4. An engine assembly comprising: an internal cornbustion engine having an air intake means and a sealed crankcase; ilow conduit means from said crankcase to said intake means; valve means in said flow conduit'means, and valve actuator means responsive to a predetermined diterential of crankcase pressure over atmospheric pressure to open and allow flow of blow-by gases from said crankcase to said intake means; and normally closed, oneway, vacuum-relief valving means between said crankcase and the atmosphere, responsive to a predetermined differential of atmospheric pressure over crankcase pressure to open and admit a controlled quantity of atmospheric air to relieve the vacuum.

5. An engine assembly, comprising: an internal combustion engine having an air intake means, a sealed crankcase, and a iller tube; flow conduit means from said crankcase to said intake means; valve means in said flow conduit means, and valve actuator means responsive to a predetermined pressure differential of crankcase pressure over atmospheric pressure to open and allow ilow of blow-by gases from said crankcase to said intake means; oil ller cap on the end of said filler tube including seal means between said cap and liller tube; passage means through said cap communicant with said tube and the atmosphere; and normally closed valve means in said cap, openable against a bias only in response to a predetermined pressure differential of atmospheric pressure over crankcase pressure to allow inflow of regulated quantities of atmospheric air to relieve said pressure differential.

References Cited by the Examiner UNITED STATES PATENTS 2,716,398 8/55 McMullen 123-119 3,080,994 3/ 63 Chausson 222-44 3,083,862 4/63 Bowden Z22-44 3,108,581 10/63 Humphreys 123-119 3,145,697 8/64 Barr 123--1 19 3,160,487 12/64 Risse et al 55-417 RICHARD B. WILKINSON, Primary Examiner.

KARL I ALBRECHT, Examiner.

Claims

1. AN ENGINE ASSEMBLY COMPRISING: AN INTERNAL COMBUSTION ENGINE INCLUDING A SEALED CRANKCASE AND INTAKE MANIFOLD MEANS; CONDUIT MEANS EXTENDING FROM SAID SEALED CRANKCASE TO SAID INTAKE MANIFOLD MEANS; GASEOUS FLOW REGULATOR MEANS FOR SAID CONDUIT INCLUDING A VALVING MEANS AND A PRESSURE RESPONSIVE ELEMENT OPERATIVELY ASSOCIATED WITH SAID VALVING MEANS TO OPEN AND CLOSE IT; SAID PRESSURE RESPONSIVE ELEMENT BEING RESPONSIVE TO THE PRESSURE DIFFERENTIAL BETWEEN POSITIVE CRANKCASE PRESSURE OVER A STANDARE PRESSURE TO OPEN SAID VALVING MEANS AND ALLOW FLOW OF GASES FROM SAID CRANKCASE TO SAID INTAKE MANIFOLD UPON AN INCREASE IN CRANKCASE PRESSURE OVER SAID STANDARD PRESSURE AND CAUSING SAID VALVING MEANS TO CLOSE UPON A DECREASE OF CRANKCASE PRESSURE TO SAID STANDARD PRESSURE; AND A ONE-WAY NORMALLY CLOSED VALVE BETWEEN SAID CRANKCASE AND THE SURROUNDING ATMOSPHERE SUBJECT TO OPENING UPON A DECREASE IN CRANKCASE PRESSURE A PREDETERMINED AMOUNT BELOW ATMOSPHERIC PRESSURE TO OPEN AND ADMIT A SMALL QUANTITY OF ATMOSPHERIC AIR TO SAID CRANKCASE UNTIL CRANKCASE PRESSURE INCREASES ABOVE SAID PREDETERMINED AMOUNT.