US3357414A

US3357414A - Vacuum breaker for internal combustion engines

Info

Publication number: US3357414A
Application number: US432538A
Authority: US
Inventors: Meserve Forrest Clayton
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-02-15
Filing date: 1965-02-15
Publication date: 1967-12-12
Anticipated expiration: 1984-12-12

Description

Dec. 12, 1967 c MESERVE 3,357,414

v VACUUM BREAKER FOR INTERNAL COMBUSTION ENGINES Filed Feb. 15, 1965 3 Sheets-Sheet 1 FIG. I

Movin Towards Idle Position INVENTOR.

Y r MW ZZZ? Dec. 12, 1967 F. c MESERVE 3,357,434

VACUUM BREAKER FOR INTERNAL COMBUSTION ENGI Filed Feb. 15, 1965 NBS 3 Sheets-Sheet :3

FIG. 2

Deceleroting in Idle Position INVENTOR.

Dec. 12, 1967 F. C MESERVE.

VACUUM BREAKER FOR INTERNAL, COMBUSTION ENGINES Filed Feb. 15, 1965 SOL. RELAY 5 Sheets-Sheet .3

FIG. 3

United States Patent 3,357,414 VACUUM BREAKER FOR INTERNAL COMBUSTION ENGINES Forrest Clayton Meserve, 19 Peters St., North Andover, Mass. 01845 Filed Feb. 15, 1965, Ser. No. 432,538 3 Claims. (Cl. 123-119) ABSTRACT OF THE DISCLOSURE A vacuum breaker for internal combustion engines comprising a casing having an air passage leading to the intake manifold of the engine with valve seats of respectively large and small areas and a single valve controlling the passage, the valve being spring-biased toward said seats, and a throttle controlled air valve for admitting atmospheric pressure to the area of said valve between the seats for unseating the valve in opposition to said spring.

This invention comprises a new and improved vacuum breaker for use with internal combustion engines for the purpose of reducing the high vacuum in the cylinders and intake manifold when the carburetor valve is closed but the engine is still turning over.

The action of such vacuum is objectionable because it causes oil to be sucked past the piston rings where it will be burned in the cylinders with the formation of carbon and also because it creates noxious exhaust fumes.

The device of my invention not only relieves the engine of this vacuum when it is not wanted but permits free influx of fresh air and so reduces overheating of the engine during deceleration.

To this end the vacuum breaker of my invention includes in its structure a casing having an air passage leading to the intake manifold of the engine with valve seats of respectively large and small area controlling the passage. In the passage is a valve body having spaced shoulders fitting the respective valve seats, means for holding the valve in closed position on both seats, and a valved air passage in the casing leading to the valve seat of larger area.

This deceleration valve automatically opens, venting the inlet manifold to the atmosphere, when the butterfly valve closes and the vacuum is high, and closes when the vacuum becomes reduced to approximately two inches or before the engine stalls.

Other deceleration valves have been produced but have not been satisfactory because of popping in the carburetor, mufiler explosions and stalling of the engine, due to an excessively lean fuel mixture caused by the failure of the deceleration valve to close before the carburetor butterfly valve is opened.

In the vacuum breaker of my invention I have eliminated the formation of a lean mixture and resultant popping, stalling and muflier explosions by installing a damper between the valve and the carburetor-to-manifold passage. This damper is actuated by the carburetor linkage so that when the foot throttle is depressed the damper is closed just before the carburetor butterfly opens, and is opened just after the butterfly valve closes.

The valve of my improved breaker is of a diminishing resistance type, and spring actuated so that a vacuum higher than that created at idle engine speed is required to open it. It is held open by the flow of air until the flow is reduced nearly to that required for idle speed and then automatically returns the manifold to pressure required for idling.

To insure that this valve does not open prematurely and that it does not flutter when closing, it has incorporated in its design two-stage atmospheric exposure. This design normally exposes only one-half the piston area to the atmosphere, except at the exact time when the valve is to open. At this time a cam-operated valve admits atmospheric pressure to the entire surface of the piston. This provides twice the normal load on the springs and as a result the piston is lifted off its seat, opening the valve to its full extent instantly.

These and other features of the invention will be best understood and appreciated from the following description of a preferred embodiment thereof selected for purposes of illustration and shown in the accompanying drawings in which FIGS. 1 and 2 are views in elevation partly in section showing the valve in closed and open positions, and

FIGS. 3 and 4 are fragmentary views illustrating modified constructions.

In the drawings a carburetor of conventional type is shown as secured to the intake manifold 10 of a gas engine through a T-fitting 11 and a flanged collar 12. The carburetor 13 has an overhead air inlet 14 and the flow of its combustible gas mixture is controlled by a butterfly shoulder valve 15 mounted on a shaft 16 journaled in the collar 12.

The valve shaft 16 is connected to a rocker arm 17 having lost motion relation with an upstanding arm 19 operated by a throttle rod 18. The arm 17 is connected to a spring 20 tending at all times to maintain the butterfly valve 15 in closed position.

The arm 19 is journaled on shaft 16 and a T-shaped sector head 21 with a curved surface from which projects a one-way tripping latch 22 arranged to depress and open a ball valve 23 located in position to be contacted by the latch in the counter-clockwise movement of the head 21. When the head 21 is moved in the opposite direction the latch 22 yields without affecting the valve 23.

The ball valve 23 controls an air passage 24 formed in a tubular casing 25 connected through a coupling 26 to the threaded transverse outlet 27 of the T 11. At its outer end the casing 25 receives a threaded nipple 28 forming an air inlet passage.

Within the casing 25 are formed two annular valve seats. The smaller is formed by an annular shoulder 29 and the larger by an annular shoulder 30.

Within the casing 12 is mounted a cylindrical valve 31 carrying on its outer end a washer 32 which cooperates with the valve seat 29 to completely close the air inlet passage when seated as shown in FIG. 1. The valve body is shouldered to fit within the valve seat 30 thus forming a second closure for the air passage 28. The air passage 24 leads into the valve chamber in an area surrounding the valve 31 in position to admit air at atmospheric pressure against an annular area of the shoulder of the valve 31.

The valve 31 is normally maintained in closed position by toggle springs 33 supported at their outer ends by a shoulder in the coupling 26. The springs 33 are selected and arranged to balance the valve body 31 in closed position against the normal vacuum created in the running engine. However, when the throttle valve 15 is closed, shutting off or reducing the flow of combustible gas and so increasing the vacuum, the valve 23 is opened by the reverse movement of the throttle rod and atmospheric pressure is admitted to the annular outer area of the valve body thus overcoming the resistance of the springs 33 and snapping the valve body into full open position admitting full flow of fresh air through the inlet passage 28 to the manifold and subjecting the full circular area of the valve 31 to atmospheric pressure.

The opening of the ball valve 23 causes the first stage atmospheric exposure of the cylindrical valve 31 under relatively low pressure but sufficient to overcome the toggle springs 33. The second stage atmospheric exposure of the valve 31 then takes place under augmented pressure acting on the full circular area of the valve.

A damper valve 34 is mounted on a shaft 35 in the outlet 0f the T 11 and provided with a counterweight head 36 which tends to hold the valve normally in open position thus leaving the air passage 28 entirely under control of the valve 31. However when the system requires fluid pressure, as for operating brakes, the valve 34 is moved to closed position as indicated in FIG. 1 by cam action of the sector head 21 on a short arm projecting from the shaft 35.

The valve 34 may, however, be controlled through a solenoid 50 as suggested in FIG. 4. The solenoid operates a rod 51 having an operating connection with the arm of the valve 34 and in circuit with a switch 52 that may be located in convenient reach of the driver or included in the backing light circuit.

An alternative construction for causing the valve 31 to open is shown in FIG. 3 where an elbow fitting 40 is substituted for the nipple 28 of FIGS. 1 and 2. To this fitting is secured a solenoid 41 operating a plunger and rod 42 that is arranged to contact the .outer end of the valve 31 and push it off its seats against the action of the springs 33."1'he solenoid is in circuit with a switch 44- arranged to be closed by action of the latch 22 when the center head 21 is moved upwardly toward driving position.

In normal operation at moderate speeds the manifold pressure may rise as high as 27 inches or more. In deceleration under these circumstances there is unbalance between the ratio of air and fuel drawn into the manifold. This causes a continual flow of unburned gas through the exhaust and continues until the engine reaches idling speed. When the throttle is closed and the manifold pressure increased the two-stage valve automatically opens thus reducing the manifold pressure to about 7 inches. Then the air flow maintains the wide open valve position until the manifold pressure is reduced to about two inches at which time the air flow rate balances the requirement of the idling engine. When this condition is reached the valve automatically closes so that the manifold may return to its normal pressure.

Having thus disclosed my invention and described in detail a preferred embodiment thereof I claim as new and desire to secure by Letters Patent:

1. A vacuum breaker comprising a single tubular casing having an air passage leading to the carburetor and the intake manifold of an internal combustion engine, concentrically arranged and longitudinally spaced valve seats associated with said passage, a valve body having concentric shoulders fitting the respective valve seats in said tubular casing, toggle springs holding the valve closed upon one of said valve seats, a normally closed air passage in said casing leading to the other of said valve seats, an air valve for admitting atmospheric pressure to the second of said valve seats, for unseating the valve body in opposition to said toggle spring, and saidvacuum breaker being characterized in that the air valve -is opened by a rocking cam having a 10st motion connection with the carburetor valve of the engine.

2. A vacuum'breaker comprising a single tubular casing having an air passage leading to the carburetor and the intake manifold of an internal combustion engine, concentrically arranged and longitudinally spaced valve seats associated with said passage, a valve body having concentric shoulders fitting the respective valve seats in said tubular casing, toggle springs holding the valve closed upon one of said valve seats, a normally closed air passage in said casing leading to the other of said valve seats, an air valve for admitting atmospheric pressure to the second of said valve seats, for unseatting the valve body in opposition to said toggle spring, and said vacuum breaker being characterized in that an additional butterfiy valve is provided in said air passage with connections to said rocking cam for closing the passage to reestablish vacuum in the manifold.

3. A vacuum breaker as described in claim 1, further characterized in that a damper valve is provided in said first mentioned air passage with means for closing said damper valve independently of the main valve.

References Cited UNITED STATES PATENTS MARK NEWMAN, Primary Examiner.

AL LAWRENCE SMITH, Examiner.

Claims

1. A VACUUM BREAKER COMPRISING A SINGLE TUBULAR CASING HAVING AN AIR PASSAGE LEADING TO THE CARBURETOR AND THE INTAKE MANIFOLD OF AN INTERNAL COMBUSTION ENGINE, CONCENTRICALLY ARRANGED AND LONGITUDINALLY SPACED VALVE SEATS ASSOCIATED WITH SAID PASSAGE, A VALVE BODY HAVING CONCENTRIC SHOULDERS FITTING THE RESPECTIVE VALVE SEATS IN SAID TUBULAR CASING, TOGGLE SPRINGS HOLDING THE VALVE CLOSED UPON ONE OF SAID VALVE SEATS, A NORMALLY CLOSED AIR PASSAGE IN SAID CASING LEADING TO THE OTHER OF SAID VALVE SEATS,