US1687176A - Means for injecting liquid fuel into internal-combustion engines - Google Patents

Description

Oct. 9, 1928. 1,687,176

s. D. OLSEN MEANS FOR INJECTING LIQUID FUEL INTO INTERNAL COMBUSTION ENGINES Filed March 18, 1925 Patented Oct. 9, 1928.

UNITED STATES :PATENT OFFICE.

$IMON DOKK OLSEN, LONDON, ENGLAND, ASSIGNOR TO THE OLSEN ENGINE SYNDI- GATE LIMITED, 0]? LONDON, ENGLAND, A BRITISH COMPANY.

MEANS FOR INJECTING LIQUID FUEL INTO INTERNAL-COMBUSTION ENGINES.

Application filed. March 18, 1925, Serial No.

This invention has reference to means for injecting liquid fuel into internal-combustion engines of the type in which an explosive charge is formed in a small injector cylinder connected with the working cylinder, and is forced into the latter by a springpressed plunger which is retracted by a cam after each injection stroke.

The invention relates more particularly to arrangements of this kind in which a portion of the compressed air in the working cylinder enters the injector cylinder and after mixing with the liquid fuel or oil to form the charge, is driven back into the engine cylinder by the plunger.

The main object of the invention is to ensure more perfect formation or atomization of the charge'and more efiicient distribution and ignition thereof in the working cylinder, this being attained by a double action, that is to say the charge in the injector cylinder being formed in two stages as it were, one stage during the backward stroke of the plunger, and the other during its forward stroke.

To this end according to one example or construction, of such a double-action injector, which is specially intended for small engines working on' the Diesel principle, the plunger is combined with an independentlymoving valve for closing the passage to the injector cylinder, this valve having also an extension piece with a head or enlargement acting both as a spreader and distributor and also as a throttlingl device for the orifice by which the charge 'nally enters the cylinder.

Another example or construction is intended primarily for use with two-stroke engines to obviate the waste in the latter due tothe unavoidable carrying away of fueloil spray or vapour along with the exhaust. It may however be applied to four-stroke engines if desired, and may be used both with light-oil, paraifin or spirit, and also with heavy oil. It may be used with either low or high compresslon and with spark" plug ignition, or in engines having self-ignition on the Diesel principle.

In this construction the injector cylinder is double-ended, the .oil or liquid fuel being taken in abovethe piston and then forced into the space below the piston as the latter rises, through a suitable port or by-pass. As it is discharged into the lower part of the 16,457, and in Great Britain April 30, 1924.

cylinder, it mixes with the air therein which has ust come from the engine cylinder, and the mixture is forced out as the piston descends, being sprayed into the engine cylinder for ignition as the working charge in the usual way.

In the accompanying diagrammatic drawmgs:

F ig. 1 represents a longitudinal section of an darrangement suitable for a Diesel engine, an

Fig. 2 illustrates a detail thereof.

Figs. 3 to 7 are diagrams showing the parts at different stages of the working stroke.

Fig. 8 illustrates the arrangement as applicable to a two-stroke engine.

Referring more particularly. to Fig. l:

a represents the top or end of the engine cylinder, 6 the injector cylinder which is in the form of a hollow block or plug firmly secured therein, 0 being the injector plunger and cl the spindle of the independent valve 6 which works down the centre of said plung- 5 which is screwed on the bottom of the cyli inder b and forms the end cap thereof.

This passage 72, is made in twoparts of different diameters; lln the wider part the above valve 6 works, whilst the narrower part is adapted to receive the head 7 of the throttling device and spreader. The mouth h of the passage forms the actual injection orifice. Y

The shoulder between the two parts of the passage h forms-the valve seat and from a point at one side of it an inclined tangential by-pass i (see also Fig. 2) leads up towards the side of the injector chamber near the. opening k of the inlet passage or passages k through which the oil is fed in under The valve-spindle d extends axially through the injector plunger 0. and both of them are adjustable and are operated independently for instance through levers d and. c beingretracted by separate cams, and returned to give their working stroke by springs. These cams and sprin s are not shown for the sake of clearness, their action and arrangement bein obvious.

The parts are so timed that when the plunger 0 has completed its forward working or injecting stroke, the valve 6 (see Fig. 3) is also in its forward and closed position, and the conical head or projection f which it carries is thrust out slightly into the engine cylinder towards the working piston 02 The valve 6 and spreader 7 remaining in this position, the plunger 0 retires slig tly (see Fig. 4) and a small quantity of oil enters the device through the inlet passage 70 after the commencement of the movement till of the piston d toward the right.

The plunger 0 then makes a further backward movement (see Fig. 5) to ensure the reduction and elimination of any residual pressure in the device, whilst the valve 6 opens to its fullest extent, and allows compressed (and therefore hot) air from the engine cylinder, due to the piston a continuing the -compression stroke, to flow through the Toy-pass a" into the injector chamber h, where it strikes the oil which has just entered by 70, and partly forms it into a spray or vapor, at the same time heat ing it. This is the first stage of the formation of the charge.

The valve 6 then half closes (see Fig. 6) so that the sprayer-head f lies right in the injector orifice 71, and partly closes or throttles it At the same time the main or injector lunger 0 moves forward and the partly formed charge is driven through the hy-pass i and thence through the throttled oritice 7L1, whereby the atomization becomes very com, lete and the charge is forced into the cylin er and past the conical head or sprayer 7" with a whirling spiral motion due to the tangential position of the passa e.

This finishes the second stage or the formation of the charge. As the latter enters the working cylinder, the explosion takes place spontaneously owing to the heat due to the compression, in the well-known manner.

The valve 6 then closes (see Fig. 7) and shuts the injector on? completely from the working cylinder, and hoth it and the valve remain at rest till the end of the working stroke in the engine. The plunger then begins to retire, and the alcove operations are repeated.

It will thus be seen that there is a clear double action as it were. the charge being partly formed as the air flows from the engine into the injector cylinder and the,

mamas or fairly easily. The rod or stem 0 of the piston passes out through a closed conical cover or gland b llt is acted on by a powerful spring 0 which tends to force the piston downward or, forward and by a camactuated lever 0 which moves it backward counter to the spring, as above mentioned. The cam ma be of any suitable shape, as even a pear-shaped cam will allow the piston or plunger 0 to work sharply enough when the engine is running at full speed. In one side of the cylinder is the oil-inlet orifice k which 'ust clears the topv of the plunger 0 when t e latter is in its lowest position. lln the opposite side but lower down is the discharge orifice from aby-pass i, which must clear the bottom of the piston 1 when the latter is fully raised, (see dotted lines). The ends of the plunger or piston may be made slightly inclined or askew so that by turning it round, the exact degrees of clearance at the orifice can be regulated I or adjusted with great nicety. The side of the piston 0 has a groove or recess in which is fitted a short piece or strip Z which is pressed against the cylinder wall near the oil inlet h by springs Z It serves (like a slide valve) to ensure proper closing of the latter as the piston moves up and down, so that the closure is complete notwithstandin that the piston is an easy fit in the cy inder. I The fuel oil inlet pipe is may also he graduated or controlled by a needle valve or as desired.

Centrally in the bottom of the injector is a conical openin 71. through which the charge is forced into the engine c linder, This opening may resemble a smal valve seat, and the piston carries opposite to it, a central pinor finger f which can enter it freely but has a conical or valve-like portion e to tit this valve seat. When the piston or plungerc is right down, the valve-like opening 71, is closed entirely, whereas when the piston is drawn right u or backward, the pin or finger f is with rawn clear out of it (see dotted lines)- and it isdeft fully open. Tn intermediate positions the pin f is in the opening and almost olosesvit, so giving a very restricted passage and ensuring good atomizing.

The lay-pass 71 extends down through the lllll lift) wall of the cylinder. It opens at one end into the top of the latter and at theother end into the bottom thereof; just below the raised position of the piston (see dotted line) as stated.

When the piston c is right down, a small quantity of oil enters through the side inlet descends or makes its forward stroke, it com pletes the mixture of oil-spray and air as it forces it back into the engine cylinder. At the same time it also covers and closes the bypass i, so that as it continues to descend, a vacuum is formed at the top of the cylinder ready to receive or suck in the next charge of oil through the inlet pipe or port It.

It may be mentioned that the injector piston need only have a rather slack or easy it in the cylinder, a fair amount of clearance being an advantage in fact in many cases. Thus the inconvenience of a tightly fitting or packed piston is avoided, and the wear and tear are correspondingly reduced. The only part which requires to be really tight is the slide-piece Z controlling the oil inlet 76.

Obviously the above arrangements may be modified in various wa s in carrying the invention into practice without departing from the general nature thereof.

1 claim:

1. lln a liquid fuel injector, the combination of an injector cylinder, a plunger working therein, means for supplying fuel to the space in front of said plunger, a lay-pass through which air is admitted from the engine cylinder at a point near the fuel inlet or preliminary atomization of the fuel, and means caried by said plunger for restricting, during the actual injection, the passage leading into the engine cylinder, substantially as described.

2. In a liquid-fuel injector, the combination of an injector cylinder, an oil-supply opening to one end thereof, a valve-controlled inlet leading to the engine cylinder, a by-pass from said oil-supply opening to near the valve seat, a plunger in which the valve stem works axially, a stem with an venlarged head for restricting the injection inlet, and means for operating the plunger and valve independently of each other, substantially as described.

3. lln a liquid-fuel injector, the combination of an injector cylinder, an oil-supply opening into one end thereof, a valve-controlled inlet passage leading to the engine cylinder for the flow of the charge one way and for that of compressed air the other Way, a valve seat at the end of said passage remote from the engine cylinder, a bypass from said inlet extending to near the valve seat, a plunger, a valve spindle working axially therein, and a stem on said valve for restricting the inlet at the moment of the injection, substantially as described.

4'. The combination ofan injector secured direct in the end of an engine cylinder, an inlet passage at the inner end of said injector leading direct to the engine cylinder made of two difierent diameters with a valveseat between them, a; plunger working in said injector, a valve for closing said passage, and a device for restricting the same during injection, substantially as described.

In testimony whereof ll afix my signature.

srMoN noun cases.

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