US1552174A

US1552174A - Method of and apparatus for reducing engine vibration

Info

Publication number: US1552174A
Application number: US389912A
Authority: US
Inventors: Willard C Kress
Original assignee: Individual
Current assignee: Individual
Priority date: 1920-06-18
Filing date: 1920-06-18
Publication date: 1925-09-01
Anticipated expiration: 1942-09-01

Description

sept.. l,

Filed June 18. 1920 Patented Sept. 1 1925.

UNITED STATES PATENT OFFICE.

WILLARD c. xREss, or BUrrAL'o, NEW Yonx.

l.Application led .Tune 18, 1920. Serial No. 389,912.

To all 'whom z't may concern:

Be it known that I, WTLLARD C. KREss, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented new and useful Improvements in Methods of and Apparatus for Reducing Engine Vibration, of which vvthe following is a specification.

This invention relates to multicylinder engines and more particularly to internal combustion engines of the single acting type such as are employed in automobiles.

The object of the invention is the provision vof a novel method of-and apparatus for reducing vibration of the engine and increasing its eiciency.

In its preferred embodiment, the improvements consist essentially in making the usual crank case air or fluid-tight and creating and maintaining a `fluid pressure therein. to provide a sustaining medium under the pistons, and in order that ascending pistons of the engine may be returned largely by descending pistons through the intervening body of compressed fluid, lthus lgreatly relieving the crank-shaft from the reciprocating load. and diminishing vibration.

The accompanying drawing represents ar posed between these sections to render thecrank case practically air tight.

Jcurnaled in. bearings 12 in the upper section of the crank case is the' engine crankshaft 13 and bolted to the upper side of said section is the cylinder block 14 in which the pistons 15 reciprocate, the'latter being connected to the crank shaft by the usual connecting rods 16, so that some of the pistons ascend while others descend.` Suitable packing 17 is interposed betweenl the 'cylinder block and the upper crank case section 10 to insure a pressure tight/jointA 'between' these parts.

In order to form a pressure tight joint at the rear end of the crank case where the crank shaft 13 projects therethrough, packing rings 18 are provided on said shaft which are ittcd the bore of a' col1ar19 suitably 'secured to the rear wall of the crank case.

The several engine-cylinders open at their lower ends into the crank case, in a manner common to this typeof engine.

lThe means for producing and maintaining a fluid pressure in the crank-case, are preferably constructed las -followsz- Bolted or otherwise secured to the front end of the crank case so as to form a pressure-tight joint therewith, isl an air .or pres-l sure pump 20, in the base 21 of which is 6 5 journaled an auxiliary crank shaft 22 preferably driven from the main crank shaft 13 of the engine. As'shown in the drawing, the front end of the engine crank shaft is provided with a reduced extension 23 which projects through .the front wall of the crank case and to which the adjacent bored end 24of the auxiliary crank shaft 22 is connected by a key 25 or other suitable r means. To establish a` pressure-tight joint 7 4 at the front end of the crank case where the engine' crank shaft projects therethrough packing rings 26'are mounted on the rear end 24 of the auxiliary crank shaft 22 which are fitted in the bore of`a collar 27 suitably 80 `secured to the adjacent wall of the engine crank case.

28 represents the cylinder of the pressure pump in which the piston 29 reciprocates the latter being connected to the crankshaft 22 by a connecting rod 3Q. .Arranged in the cylinder head 31 is a port 32 communiL eating with the atmosphere 4and controlled by an inlet valve 33 which opens inwardly by the suction produced on the downward stroke of the piston of said cylinder. This valve is ,yieldingly held to its seat by a spring 34 surrounding the stem 35 of the valve and bearing at its lower end against the top of the cylinder head and at its upper end against a washer 36 adjustably held on the stem by a nut 37. 38 indicates the outlet port of the pump controlled by a valve 39, which opens outwardly by thepressure produced in the cylinder on the upward stroke of the piston', and whichisyielding- Iy held to its seat by a spring 40 surrounding the stem 41 of said valve which is pref-` erably guided in a plug 42 screwed into the 105 upper side of the cylinder head. The air expelled through the Outlet port 38 enters a chamber 43 in the Cylinder had which 48 of the valve and adiust-ably mounted thereon by a nut 49.

The operation of the engine is as follows:

Assuming the engine to be running, the pump-shaft 22 is compelled to turn with the engine crank shaft 13, reciprocating the pump-piston 29. On the downward stroke of this piston, air under atmospheric pres.- sure enters the pump cylinder through the` port 32, and on its upward stroke said piston expelsthe air from the cylinder through the outlet port 38 into the chamber 43 and thence through the passage 44 into the engine crank-case. Thus, a pressure is built up in said case which acts as av power-transmitting Huid or cushion between the adjacent ends of the several pistons, whereby a portion of the explosion-pressure exerted on a descending piston is simultaneously exerted through the cushion on an ascending vpiston to effect its return stroke, with the result that the strain .or reciprocating load incident to raising or returning the pistons is'largely removed from the crank shaft and the connecting rods, thus reducing vibration to the minimum. This cushioning or pressure medium acts with equa-l pressure on the bottoms of theascending and descending pistons, which are all of equal areas, and

the pressure is thus neutralized and does not retard the movement of the pistons. It is evident that such pressure maintains a constant upward torque or pull on the crank shaft, connecting rods and pistons, but without resisting rotation of said crank shaft or movement of the pistons. The explosive forceor pressure acting on a descending piston does not turn the crank shaft solely through the customary direct thrust of the piston and connecting rod, but a considerable portion of that force is exerted indirectly on the crankshaft through the moving. or displaced air cushion which acts ou the ascending piston or pistons and causes them to pull upward on the cranks of the shaft. While the explosion stroke is thus transmitted to the crank shaft partly1 through the ascending-piston or pistons, it

. is evident that the shaft is relieved'from a considerable part of the reciprocating load, beca-use, after descending, a piston is not returned.' solely by the connecting rod and Crank pin but is in a great measure r6' turned by the descending piston and the movmg air cushion. It follows that vibra-' necting rods, resulting in destructive wear and vibration. By providing a sustaining and transmitting medium of compressed air or similar fluid under and between the pistons,such reciprocating load or the strain of the'return stroke of the piston is taken olithe crank shaft,.as above explained, reducing vibration and securing the above-mentioned advantages.

Any required pressure may be maintained. in the crank case by adjusting the nut 49 to increase or decrease the tension of the spring 4:

The degree of' air pressure necessary t0 neutralize the inertia loads at the vforward end'of the'piston stroke is dependent upon the effective area of the piston and the weight of the reciprocating mass, and to secure maximum eiiiciency, it is ldesirable to vary the pressure according to the speeds, since it is apparent that greater pressure is l required at high speeds than at low speeds.,

The most eiicient pressure for any given speed can readily be determined in practice, and is merely a matter of adjusting the regulating nut 49. For example, an engine having a cylinder with a three-inch bore and a three-inch stroke, with a reciprocating `mass weighing two pounds and a crank rotating at a speed of 4,00() R. P. M., will require a fluid pressure in the crank case of approximately one hundred and forty pounds to the square inch.

It will be observed that the fluid-tight crank case forms a fluid-pressure chamber or conduit with which the adjacent open ends of the several engine cylinders communicate and byI which they are connected, so that thel pressure fluid acts as a powertransmitting medium between'the descending and ascending pistons whose lower ends are exposed thereto.

The engine cylinders as well as the crank case are fluid-tight at all times, and a practically constant and uniform air pressure or tension is therefore maintained in the crank case and against the lower ends of the pistons throughout their forward and backward strokes.

I claim as my invention:

1.k The herein described method of relieving the crank shaft of a single acting multiple-cylinder Iinternal combustion en ine from the reciprocating load to reduce vi ration, which consists in transmitting the Lasagni 8h posed medium of compressed Huid, confined front ends of the oppositely-moving pis- 10 under pressure. tons being exposed to the pressure-medium 2. The combination of a single acting in said conduit, whereby the movement of a multicylnder internal combustion engine, descending piston is transmitted to an as- 5 a fluid pressure conduit communicating with cending piston by said pressure-medium,

and'connecting the engine cylinders, said and means for producing fluidfpressure in u conduitl and said cylinder being fluid-tight to said conduit. prevent the release of Huid and maintain a substantially constant pressure therein, the WILLARD C. `KRESS.