US2019298A - Internal combustion engine - Google Patents

Description

Oct. 29, 1935. H. FISCHER 2,019,298

INTERNAL GOMBUSTIN ENGINE Filed Apri 1 25, 1932 13 gwn/roc H HNS FTSIJHER.

Patented Oct. 29, 1935 UNITED STATES PATENT OFFICE INTERNAL CONIBUSTION ENGINE Hans Fischer, Milwaukee, Wis., assigner to The Falk Corporation, Milwaukee, Wis., a corpora- This invention relates to internal combustion engines tion of Wisconsin Application April 25, 1932, Serial No. 607,271

4 Claims,

of the type wherein the fuel, ordinarily oil, is injected into an air charge previously admitted to the combustion space.

One object of the present invention is the provision of an improved engine of this type which will operate smoothly and eiciently throughout a wide range of speed. This I have accomplished use of a novel combination and arrangeby the ment of parts which function to effect an unusually prompt and sure ignition of the fuel charge substantially at the instant of fuel injection and to effect an early and complete combustion of the fuel without producing an explosive effect. The

ignition lag characteristic of the Diesel cycle has thus been substantially eliminated, making possible emcient operation at relatively high speeds, and at the same time the explosive effect characteristic of the Otto cycle has been avoided, thus keeping the mechanical stresses within relatively low limits so as to permit the safe use of a relatively light construction.

Another object is the provision of improved means for effecting a violent turbulence of the fuel and air charge during combustion so as to promptly effect a complete and thorough mixture thereof and thereby insure vcomplete combustion of the fuel within a very early stage of each working stroke.

Other more specic objects and advantages will appear from the following description of an illustrative embodiment of the present invention.

The single gure of the accompanying drawing is an axial sectional view of the head end of an engine cylinder constructed in accordance with the present invention.

The engine selected for illustration is designed to carry out a four stroke cycle, but the invention may be applied with equal advantage to engines of the two stroke cycle type.

The cylinder shown at III is provided with the usualwater jacket II and with a water cooled head I2 with which the reciprocating piston I3 coacts to form the expansible combustion space or chamber I4. 'Ihe cylinder is also equipped with the usual inlet and exhaust valves (not shown) each of which controls communication between the chamber I4 and one of the usual pair of conduits I5 formed in the head.

An inwardly flaring throat I6, formed in the head I2 communicates with the chamber I4 and forms in effect an extension or continuation of a longitudinally tapered pre-combustion chamber I1. I8 who Chamber I1 is preferably formed in a plug se upper end is slightly enlarged and (Cl. 12S-32) flanged, as at I9, so as to seat rmly against an internal shoulder within a pocket 20 formed in the cylinder` head. The plug I8 is retained in place by a hollow plug 2| adapted to receive and. support the fuel injection nozzle 22, both plugs 5 I8 and 2| and nozzle being secured in the pocket 20 by an appropriate Iclamp structure, including the bolts 23.

Except for a detail hereinafter mentioned, the nozzle 22 is of a type commonly employed for in- 10 jecting fuel under pump pressure. In this instance the nozzle 22 is arranged to project an oil spray a into and axially of the chamber I1, the tip 24 of the nozzle being provided with an auxiliary orifice designed to direct an auxiliary oil l5 spray b through a narrow slot 25 formed in the side of the plug I8.

Except for the upper supporting end thereof, the plug I8 is spaced from the interior walls of the pocket 20 to provide a narrow peripheral 20 clearance space 26 and end clearance space 21, so as to effectively check transmission of heat to the water cooled cylinder head and thereby maintain the plug I8 at a relatively high temperature during operation of the engine, and also for an addi- 25 tional purpose which will later appear. The clearance spaces 26 and 21 are of a width approximating the width of the slot 25.

A second pre-combustion chamber 28 is provided, disposed to receive fuel from that auxiliary 30 spray b projected through the side slot 25. Chamber 28 is formed in a sleeve like member 28 positioned within a side opening 30 formed in the cylinder head I2 with the sleeve preferably spaced from the walls of the opening so as to maintain the walls of the sleeve at a relatively high temperature. The sleeve 29 is supported by an integral head 3I securely fixed within the outer shouldered end of the opening 3D. The inner 'open end of the chamber 28 communicates directly 40 with the peripheral clearance space 26 surrounding the plug I8.

The stroke of the piston I3 is preferably such that, at compression dead center, it barely avoids contact with the inner face of the head I2, so that practically all of the air has been displaced from the space I4 within the cylinder proper, although some departure fromthat condition will not defeat the purposes of the present invention.

In the drawing the piston I3 is moving upwardly on a compression stroke compressing the fresh air charge ahead of it into the throat I6 and chamber I1, and through the clearance spaces 26 andv21 and slot 25 into the chamber 28. 55 y is, thereby increased so Just before compression dead center, fuel under pump pressure is injected through the nozzle 22 to form the sprays a and b. The fuel injection preferably begins about ten degrees ahead of dead center, although this timing may be ad vanced or retarded in accordance with variations in engine speed. For higher speeds an earlier injection is desirable.

'I'he fuel contained in the spray b is heated to an ignition temperature during its passage between the hot walls of the slot 25 so that some of it is immediately ignited as it contacts the air in the pre-combustion chamber 28. vFurthermore, the turbulence produced in the chamber 28 by the high velocity ow of air thereinto through the narrow clearance spaces 26 and 21 and slot 25 produces a thorough mixture of the air with the fuel in spray b causing rapid combustion thereof. The instantaneous rise in pressure, resulting from this early ignition, and the maintenance of that pressure by the rapid combustion in chamber 28, causes the chamber 28 to discharge forcibly through the clearance spaces 26 and 2l into the throat I6 and also, to a lessr degree, thrcaigh the slot 25 into the pre-combustion chamber Il.

In the meantime the fuel contained in the simultaneously formed spray a absorbs heat from the walls of the chamber l1 and its temperature as to prepare the same for quick burning. It is ordinarily ignited by the hot gases discharged into chamber I1 through the slot 25, as a result of the early ignition in the chamber 28, before the temperature thereof has increased sumciently to produce auto--ignition.

An unusually prompt ignition of the fuel in both sprays is thus effected. Explosive burning, with consequent excessive peak pressures, are avoided however, and this I attribute largely to the fact that combustion of al1 of the fuel in the spray a is impossible until each particle thereof is brought into intimate contactwith air in suincient volume to support combustion, a condition attainable only by thoroughly mixing the fuel and air.

In this instance combustion continues as the piston I3 starts downwardly` on a working stroke and permits the hot gases to expand against it into the space H. During this now of unburned fuel and air from the chamber I1 through the throat I6, -the unburned fuel and air from the chamber 28, passing at high velocity through the clearance spaces 26 and 21, also enter the throat I6, causing a severe turbulence therein which is effective to thoroughly mix the unburned fuel and air and .produce rapid and thorough combustion.

Turbulence is also produced in the upper end of the chamber I1 by the admission of the hot gases thereto through slot 25, so as to thoroughly clean the nozzle tip 24 of any fuel adhering thereto. The downward flow through the chamber I1 also insures complete burning of any fuel deposits on the interior walls thereof.

Although the relationship of the volumes contained in chambers l1 and 28 and of the slot 25 and clearance spaces 26 and 21 is dependent upon many factors inherent in the design, I have attained excellent results with parts proportioned as indicated on the drawing in an engine having pistons of four and three quarters inches in diameter with a six and one half inch stroke.

I claim:- 5

1. In an internal combustion engine of the oil burning type the combination of a cylinder, a piston reciprocable therein coacting therewith to form a combustion space, an auxiliary chamber,

a throat providing unrestricted communication 10 between said chamber and space, means for forming a fuel spray in said chamber, a second auxiliary chamber, means for admitting fuel to said second chamber and a communication between said chambers including a restricted passage enl5 circling said rst named chamber through which said second auxiliary chamber discharges its contents at high velocity into said throat to thereby create a turbulence within the discharge from said rst named auxiliary chamber.

2. In an internal combustion engine of the oil burning type the combination of a cylinder, a piston reciprocable therein coacting therewith to form a combustion space, an auxiliary chamber arranged to discharge into said space, means 25 for forming a fuel spray in said chamber, a second auxiliary chamber, means for admitting fuel to said second chamber, and a communication between said chambers including means encircling said rst named chamber for directing a0. the discharge from said second chamber into the discharge from said first named chamber to create a turbulence therein.

3. In an internal combustion engine of the oil burning type the combination of a cylinder, a 35 piston reciprocable therein coacting therewith to form a combustion space, an auxiliary chamber. having uncooled walls and arranged to discharge its contents into said space, means for directing' a fuel spray into said chamber, a second aux- 40 iliary chamber having uncooled walls, means for admitting fuel to said second chamber, and a. communication between said chambers including means encircling said ilrst named chamber for directing the discharge from said second cham- 45 ber into the discharge from said ilrst named. chamber.

4. In an internal combustion engine the combination of a cylinder having a head, a piston reciprocable in said cylinder and coacting with 50 a throat leading from said pocket to said space 55":

and communicating with said chamber, said head having a side opening therein communicating with said pocket, a second hollow open ended plug xed in said opening and forming a second auxiliary chamber communicating with said 30- pocket, a slot formed in the side of said ilrst named plug, fuel injection means for directing a fuel spray into said iirst named Yauxiliary chamber and for directing a second spray throughsaid slot into said second auxiliary chamber, and a 05 narrow clearance space between said first named plug and pocket through which the discharge` from said second auxiliary chamber is directed' into the discharge from said first named auxiliary chamber.

HANS FISCHER.

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