US2323304A - Automatic pressure control for engines - Google Patents

Description

July 6, 1943- R. H. BCSWMAN v 2,323,304

AUTOMATIC PRESSURE CONTROL FOR ENGINES l Filed Dec. 17, 1941 Patented July 6, 1943 AUTOMATIC PRESSUREI CONTROL FOR OFFICE ENGIN Fort r Unitedv States Ind.

Applicata@ December 17, 1941, serial No. 423.3% 7 olaimg (ci. 12e-182') (Granted under the act ci' amended April 30, 1928;

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to apparatus for controlling the compression of engines, particularly those engines of the Diesel type which have a high compression ratio.

An object of this invention is to provide automatic means for opening the valves in an engine cylinder during the initial starting period and .to provide automatic means responsive to a condition of the engine for allowing those valves to be operated sequentially.

Another object of this invention is to provide means which facilitate starting an engine.

Another object of this invention is to provide a safety device which will stop operation of the engine when its lubricating system fails, and to prevent subsequent starting of the engine as'long as the cause of failure is present.

Another object of this invention is to provide means which facilitate starting an internal combustlon engine and which also becomesoperative to stop operation of the engine when the pressure in the lubricating system of the engine falls below a certain value.

Another object of this invention is to provide means which radically reduces the torque required to start combustion engines, particularly Diesel engines.

Another object of this invention is to` provide means to facilitate starting so that a smaller starting unit and battery may be employed.

Another object of this invention is to providev means which allow a higher starting speed in internal combustion engines.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawing in which:

Fig. 1 discloses a plan view of the rocker arm mounted on its housing and taken substantially on line of Fig. 2.

Fig. 2 discloses a section through the rocker arm assembly taken substantially on line 2 2 of Fig. 1 and discloses the rocker arm in operating relationship to the cam shaft and lubricating system of the engine.

Fig. 3 is a view of the rocker arm assembly taken substantially on line 3 3 .of Fig. 1.

Referring to the drawing wherein like numerals designate like parts, the system disclosed in Fig. 2 includes the internal combustion engine March 3, 1883, as are o. a. '157) cylinder lll androne of its associated valves which is normally biased in closed position by its spring l2. Valve I may be the inlet valve or the exhaust valve for the gases of the engine and in the drawing valve is an exhaust valve. Cyl'- inder l@ may be either water cooled or air cooled and may be provided with passageways i3y for cooling iiuid.

Valve stem Ha has fastened thereto the spring seat |13 having a at surface la upon 'which the rocker arm roller 'tais adapted to roll as the rocker' arm l5 is pivoted about its axis.

Rocker'arm I6 has a circular hollow portion .96h (Fig. 3) into which fluid cylinder l1 snugly ts so that the rocker arm may pivot on the outside surface of cylinder Il; cylinder is held stationary on the housing I8 due to the clamping action of circular flanges lla, |9a against housing i3 when the closure member i9 is screwed into the cooperating portion of the fluid cylinder. Circular inner housing flanges |811; |80 limit the movement of the rocker arm in the axial direction of the fluid cylinder.

rI'he fluid cylinder I1 has a piston 2| therein having a projection 2|a which is adapted to pass through the axially extending aperture Hb and to be guided by the walls of aperture l'lb when the piston 2| is moved. Spring 22 disposed between the piston 2| and uid cylinder wall llc normally biases the piston 2| to its furthermost left position as in Fig. 3. An oil tight slid-y ing connection is made between the cylinder |l and its piston 2| by mounting piston rings on the piston 2| as is well understood in the art.

Closure member I9 has fastened thereto, by welding or other means, tubing 2li through which fluid (oil) passes into the fluid cylinder via closure member opening Iilb. Fluid pressure from theengine lubricating system causes piston 2| to move to the right in Fig. 3 against the action of spring 22.

Rocker arm I6 has a groove |611 into which piston projection 2|a vmay extend only when rocker arm is in a position corresponding to the open position of valve in that case the rocker arm I6 is locked and cannot move in a clockwise 'direction (Fig. 2) and hence the valve is held open until piston projection 2|a is vWithdrawn in fluid cylinder Il is high enough -to overcome the biasing action of spring 22 then piston 2| will move to the right (Fig. 3) carrying along with it piston projection 2|a which moves into housing grooverlagso that the motion of rocker arm |6 will not be blocked by the piston projection; when the pressure in the iluid cylinder I1 due to the pressure in the lubricating system falls below a predetermined value as related to the tension of spring 22 then piston projection zla will return into the rocker arm groove Ia and lock the rocker arm.

The rocker arm I6 is actuated by circular push rod 30 having the circular extension 30a which which is resiliently telescoped within a hollow portion within push rod 30 by means of spring 23 in the hollow portion. This resilient telescopic connection allows unrestricted movement of the push rod 30 when the rocker arm I6 is locked by piston projection 2Ia; and while the rocker arm is locked sufficient force is transmitted to the rocker arm IB through resiliently coupled extension 30a so that the piston projection 2Ia may freely float into groove lila without substantial friction between piston projection 2Ia and the rocker arm walls which define groove Nia, when the predetermined uid pressure has built up in uid cylinder l1, Thus, with this feature a small cylinder and piston may be used and the rocker arm bearing which includes the nuid cylinder may be made compact.

The push rod 30 is coupled to the cam shaft 24 of the engine in a conventional manner whereby as the shaft 24 rotates push rod 30 will be raised and lowered as cam 24a revolves. The cam shaft 24 is geared .to the main crank shaft (not shown) of the engine by conventional means (not shown).

A pump 25 is coupled to cam shaft 24 by means of gearing or the chain drive 26 so that oil from the engine crank case (not shown) may be pumped to the cam shaft bearings 21, 28 conduit 29 and also to the fluid cylinder l1 via conduit 20 when pump 25 is operated. The oil intake pipe 26 extends downwardly into the usual crank case (not shown) and carries an oil strainer 21 on its extreme kend.

In Figure 2, the cam 24a is shown not in its highest position but in a position approaching the highest position and the push rod shoulder 30b is just about to engage the cooperating shoulder 30e on 30a. As the cam 24a moves from the position shown in Fig. 2 to its highest position, rocker arm I6 will be rotated counterclockwise a small amount and valve Il will open further; sufcient clearance in groove 16a for piston projection 2Ia is provided so as to accommodate this small amount of rocker arm counterclockwise movement and. it is within that range of movement that the piston projection 21a may be retracted from the groove Ilia without friction between projection 2Ia and the walls which denne groove |6a.

l'When the piston projection 2la is retracted from the rocker arm groove laagainst compression spring 22 due to oil pressure no impediment is then present for the conventional movement of rocker arm I6 and rocker arm compression spring l2 will then be permitted to close valve Il in the conventional period of its cycle. Thus, when projection 2la is withdrawn from rocker arm groove I6a the conventional fuel compression will occur in cylinder Il! and conventional igniting means (not shown) will serve to ignite the compressed fuel in ,cylinder lll.

It is understood, of course, that the engine is started by auxiliary conventional driving means (not shown) and the purpose, inter alla, of the means disclosed herein is to hold the cylinder valve Il of the engine open until the auxiliary conventional driving means (not shown) has through imparted a large amount of momentum to the operating parts of the engine; the exact amount of momentum in this instance is measured in terms of the pressure developed in the engine lubricating system as the auxiliary conventional driving meansv (not shown) moves the movable parts of the engine. The term auxiliary conventional driving means in this specification is meant to include a conventional manual operable crank engageable with the conventional crank shaft which is coupled to the cam shaft 24 or is meant to include an auxiliary motor, such as electric, which is releasably coupled to the conventional crank shaft (not shown).

Also, since the position ofthe locking piston projection 2|a is related to the pressure in the lubricating system it is clear that if the lubricating system should fail when the engine is operated in response to fuel supplied to it, the cylinder valve Il will be blocked open with the result that the engine will eventually come to a standstill.

I claim:

l. A system for controlling the operation of an engine having a cylinder and a cooperable valve for controlling the pressure in said cylinder,

means for actuating the valve in its normal cycle including a rocker arm, said system comprising a fluid cylinder having an aperture and upon which the rocker arm is pivotally mounted,

a piston in the fluid cylinder and having a projectionadapted to pass through the fluid cylinder aperture, means on the rocker arm and cooperating with the piston projection for positively locking the rocker arm, a fluid supply means for imparting pressure to said uid, and means for conduct-ing said fluid under pressure to actuate the piston projection.

2. In an internal combustion engine having a rocker arm, a fluid cylinder having an axially extending aperture, a pair of spaced flanges on .the cylinder, a piston in the cylinder and having a projection extending through the aperture and adapted to move in the aperture, said rocker arm being pivotally mounted on the cylinder and between the flanges, and said rocker arm having an axially extending groove for the reception of the piston projection.

3. The same as in claim 2 and resilient means between a portion of the cylinder and the piston for normally holding the piston projection in the rocker arm groove.

4. In an internal combustion engine having a rocker arm, a uid cylinder having an axially extending aperture, a housing having a, pair'of spaced supports, a pair of spacedflanges on the cylinder and adapted to clamp the housing supports, a piston in the cylinder and having a projection extending through the aperture and adapted to move in the aperture, means for pivotally mounting the rocker arm on the cylinder and between the housing flanges, said rocker arm having an axially extending groove for .the reception of the piston projection, and one of said supports having a groove aligned with the cylinder aperture for the reception of the piston projection.

5. A system for controlling the compression of an engine having a cylinder, a cooperable valve for controlling the pressure in said cylinder, a pivot and a rocker arm carried by said pivot for actuating said valve in the normal operation thereof, said vsystem comprising a piston received in said pivot, means on said piston for locking said rocker arm in an open position of said valve, and fluid means responsive to the operation of the engine for actuating said piston.

6. A system for controlling the compression of an engine having a cylinder, a cooperable rocker arm in an open position of the valve and fluid means responsive to operation of the engine for actuating said piston to remove said means on said piston from locking position.

'1. A system for controlling the compression of an engine having a cylinder; a cooperable valve for controlling the pressure in said cylinder, and a rocker arm for actuating said valve, said system comprising a hollow pivot xedwith respect to the engine for supporting the rocker arm, a piston in said pivot., a longitudinal slotl in said pivot, a projection on said piston engageable in one position of the piston with both said slot and said rocker arm, spring means associated with saidl piston normally biasing said projection into said slot to lock the rocker arm in a position with the said valve open, and fluid means responsive to operation of the engine for actuating said piston to remove said projection from said slot against the pressure of said spring means. t

RAYMOND BOWMAN.

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