May 4, 1943. H. R. RICARDO 2,318,333 INTERNAL COMBUSTION ENGINE OPERATING on the - TWO-STROKE CYCLE with LIQUID FUEL Injection Filed Jan

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May 4, 1943. H. R. RICARDO 2,318,333 INTERNAL COMBUSTION ENGINE OPERATING ON THE - TWO-STROKE CYCLE WITH LIQUID FUEL INJEcTIoN Filed Jan. 17, 1940 ‘ 4 Sheets-Sheet 1 May 4, 1943. H. R. RICARDO ~ 2,318,333 INTERNAL COMBUSTION ENGINE OPERATING ON THE TWO-STROKE CYCLE WITH LIQUID FUEL INJECTION Filed Jan. 17, 1940 \ 4 Sheets-Sheet 2

mu,’ 7 A ttIn'ney .( May 4, 1943. ' H, R, RICAYRDO I 2,318,333 INTERNAL COMBUSTION ENGINE OPERATING ON THE TWO-STROKE CYCLE WITH LIQUID FUEL INJECTION , Filed Jan. 17, 1940 4 Sheets-Sheet 3

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A Home): May 4, 1943. ' H. R. RICARD/O 2,318,333 . INTERNAL COMBUSTION ENGINE OPERATING ON THE TWO-STROKE CYCLE WITH LIQUID FUEL INJECTION Filed Jan. 17, 1940 4 Sheets-Sheét 4

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A Home) ‘Patented. May 4, 1943 I 2,318,333 ,

UNITED; STATES PATENT OFFICE ’

INTERNAL COMBUSTION ENGINE organ- ING ON The 'rwo-s'rnoxn CYCLE wrrII uoom FUEL INJECTION - _ Harry Ralph Ricardo,_ London, England Application January 17, 1940, Serial No. 314,323 Q / In Great Britain‘ January 17, 1939 c _ 4 Claims. ((1123-32) This invention relates internal combustion s only through one or more relatively narrow pas

engines operating on the two-stroke cycle with sages. " v > / liquid fuel injection but employing fuel which is ' Where the combustion chamber in the cylinder always spark-ignited and thus distinctfrom en- ’ head, is of a bulbous form, theidiameter of the gines operating with compression ignition. throat or mouth is ‘such that the cone ofvfuel de-' According tothis invention an engine operat - livered from the injector along the cylinder axis ing on the two-stroke cycle is provided with a will pass substantially .clearthrough the mouth sleeve valve and 'has‘end to end scavenging the into the cylinder, avoiding as far as practicable fuel being injected directly into the cylinder by .a fuel 'particles ‘striking the wall of the throat, timed pump which delivers the fuel from an in 10 In other words the diameter of the cone of fuel jector located in the end of the cylinder adjacent where it passes through the mouth or throat is to the sparking plug or plugs and remote‘ from less than the minimum diameter of the mouth?‘ the piston controlled scavenge ports, thechar Thus substantially the whole of the fuel injected acter and direction of the fuel spray, the axis of will meet and mingle with the airentering the which is substantially coincident with the cyl-_ 15 cylinder after the uncovering of the scavenge inder axis, and the timing of the fuel injection ports by the piston and as this air ?ows towards causing the fuel to meet the entering air and the inner end of the cylinder to displace ‘the ex mingle with it during the latter part of the haust gases as they ?ow out over the inner end scavenging period. Scavenge ports are formed. of the sleeve through the exhaust ports, which as in the sleeve which register with ports in the 20 mentioned are located at the wall of the cylinder 'wall of the cylinder itself. when the ports in towards its inner end. ‘- ‘ the sleeve are uncovered by the‘piston. The ‘The face ‘of the piston may be flat or dished exhaust gases ?ow out over- the inner end of the vover the whole or greater part of its face or be sleeve and through ports formed in the wall of otherwise formed as found desirable. The face of the cylinder towards its inner end. The timing of 25 the 'piston should be symmetrical, that is to say the fuel injection may be arranged so that the ' distinct from pistons of known type having asym injection period ends at the same angular tim metrical depressions in or projections on their‘ ing at all loads, but commences earlier with in faces. . , ~ ' creased load. ' -- The improved engine preferably operates with The fuel injector itself may be disposed in the 30 a compression ratio of the order - ot' approxi~ head of the cylinder so that the axis of the/in; ‘ mately 7 to 1. ' jector is coincident with the cylinder axis. For The accompanying drawings illustrate by way constructional reasons, however, the injector may of example two alternative constructions that be arranged so that its axis lies at‘an angle to may be employed in carrying the invention \into the cylinder axis, but then the nozzle is formed 35 practice. In thesedrawings-—. ' so that the fuel jet itself will have its axis sub Figure 1 is a diagrammatic sectional eleva- - stantially coincident- with the cylinder axis. The tion of a cylinder of the improved'engine show formation of the cylinder head and of the fuel jet ingv a construction‘in which the cylinder head is itself are symmetrical with respect to'the cylin- ' formed with a‘. conical combustion chamber der, the contour of the combustion chamber in 40 therein. 1 ' " _ I the cylinder head varying, however, as found con‘ Figure 2 is a partial sectional elevation showing venient. For example this combustion chamber the gearing arrangement. ‘. . . - may be conical or bulbous. That is to say it may Figure 2A is a sectional elevation in the plane comprise a bulb which is a ?gure of revolution of the crankshaft axis showing a‘ single cylinder about the cylinder axis and communicates with 45 engine [embodying the present invention the head‘ the cylinder through ' a somewhat constricted of the cylinder in this case having in it a combus throat or mouth; the diameter of the latter, how tion chamber of bulbous form; > v - - ever, being of such size in relation to the maxi Figure 3 is a sectional elevation in a plane at _ mum diameter of the bulb in a plane normal to ‘ right angles to the plane‘of Figure1'2 showing the the cylinder axis,‘ and to the diameter of the .570 same construction as is illustrated in? Figure 2. cylinder that the combustion chamber falls with _ Referring to Figure 1‘ the cylinder A‘ is provided in the category of such chambers which are desig with one ormore air ‘inlet or‘scavenge ports B nated as being in “open” communication with situated where they will be uncovered by the pis= the cylinder, as distinct from a combustion ton C towards the end'of'its outstroke.. These chamber which communicates ‘with the cylinder ports are preferably ‘symmetrically. arranged and l 2 2,318,333 . . V p lead from a scavenge air belt surrounding the cyl ' to the plunger axis. This gives a constant cut-0t! inder. The exhaust ports D are formed in'a simi _ to the fuel delivery. \, lar way in the cylinder wall towards its inner end . - Referring now to Figure 2A of the drawings, in these ports opening intoan exhaust gas belt. the single cylinder engine here shown the cylinder The sleeve valve E has ports E1 therein which at A has in thewhead F1 a combustion chamber H1 the proper time in the cycle will register with the of bulbous form. That is to say the chamber in scavenge ports B in the cylinder wall. The actual this instance is substantially spherical having a inflow of scavenge air is controlled by the move large mouth H2 which gives open communication ment of the piston C over these ports E1 in the between thechamber and the end of the cylinder. sleeve the dimensions of these ports being deter 10 The diameter of this mouth H2 is less than the mined accordingly and broadly speaking being maximum diameter of the chamber H1 and the severally smaller than the corresponding port or cone of fuel delivered into the chamber by the ports B in the wall of the cylinder itself. The centrally placed injector J has a diameter less movement of the sleeve E determines the uncov than the diameter of the mouth H2 where this ering of the exhaust ports D the exhaust gases fuel cone passes through the mouth into the cyl ?owing out from these ports in the cylinder wall inder. Two sparking plugs G are conveniently ar but over the end of the sleeve E. ranged oppositely in the chamber H1 and sym The cylinder head F is preferably detachable metrically with respect to the cylinder axis, the and in the example shown in Figure 1 is conical centre of the bulbous chamber lying in this axis. with two sparking plugs G which are symmetri 20 The face of the cylinder head F1 around the cally, that is oppositely, disposed towards the in mouth H2 of the combustion chamber H1 is slight- . ner and smaller end of the cone which consti ly conical. The face of the piston C is conven tutes the contour of’ the combustion chamber H. iently dished as shown. These plugs are thus adjacent to the fuel injector The scavenge air enters by way of the passage J which is mounted centrally at the inner end of B2 into the scavenge air belt B1 and passes thence the conical combustion chamber. In this case the through the ports‘ B when the ports E1 in the fuel injector 'is mounted with its axis coincident sleeve E register with these scavenging air ports with the cylinder axis and delivers the timed fuel and the ports in the sleeve-are uncovered by the jet in a cone J 1 with an apex angle of the order of piston. The ‘air thus entering the cylinder meets the cone of injected fuel which mingles with the approximately 30°-35°, the conical combustion 30 chamber H having a larger apex angle, say of air. The exhaust gases pass out over the top the order of 60°. The angles of the cone of fuel edge of the sleeve valve E and by way of the ports spray and of the combustion chamber are such Din the wall of the cylinder A into the exhaust in relation to the diameter of the cylinder A. and gas belt D1 whence these gases pass away through the distance from the injector nozzle to the piston the manifold D2, D3 (see. Figure 3). C that when the piston is on the outer dead centre The fuel pump K which is conveniently of some the fuel, if it were then injected,_would strike known type has two_ cylinders the plungers in the face of the piston without the margin of the which are actuated by cams arranged at 180° cone ?rst striking the wall of the sleeve E. Thus apart so that‘ when fuel is being delivered by the fuel spray will meet directly the scavenging 40 the one plunger through one of the delivery pipes air entering through all the scavenge ports B and K1 to the injector J, the other. pump cylinder is will mingle with the entering air just before these being charged by the plunger in that cylinder ports are covered by the piston on‘ its in-stroke. which is moving in the opposite direction. The that is- to say during the latter part of the scav pump is driven at half engine ‘speed ‘and the drive - enge period. conveniently comprises the gear wheels L, L1 the The scavenge ports E1 in the sleeve E are prefer latter being on a shaft L2 driven by‘a chain L3 ably so formed that the in-flowing air is not given from the engine crankshaft M. This arrange any circulatory motion within the cylinder due to ment enables the engine to be ‘run at a higher the action or form of the sleeve ports. speed than that at which the pump will function ’ By arranging the fuel injection so that the start satisfactorily while the pump will deliver an in of the injection period may be varied while main jection of fuel into the cylinder at every revolu taining constant the termination of this period, tion of the crankshaft. The magneto N is driven_ economic running is obtainable. As the load de _ through .the chain L3 and gear wheels L, L1 by creases and the amount of fuel injected is also means of which the pump is driven as described decreased, it is desirable for economic reasons to above. ' r cause the injection period to commence later. The cylinder casting A in which are the ex Conversely, to obtain greater or‘ maximum power haust ports D may have between these ports bars - the period of injection should begin earlier. In A1 extending in the direction of the cylinder each case the termination of the injection period » length these bars being cooled by water passages A2 through them. ‘Owing to the movements of should be ?xed. 60 To enable this variation in the fuel’ injection the sleeve E the bars A1 serve to carry lubricant period to be effected a fuel pump of known type from that part of the cylinder bore which lies may be used having a plunger which is rotatable below the exhaust ports D to the part of- that in its cylinder for the purpose of varying the tim bore which lies above these ports. ' I ll'ig of the fuel injection, ‘this rotation varying the The lubrication of the cylinder bore is effected eli‘ective length of the pump plunger, that is to by supplying oil by way of the pipe 0 to the say its stroke in relation to ?xed ports in the cyl annular groove 01 in the wall of the cylinder inder wall. In the present case such a pump may With regard to the timing of the fuel injection. be formed with the face, or other part of the it is desirable to provide means by which the plunger which determines the commencement of - proper proportions of air ‘and fuel are maintained. the injection period, inclined or with an inclined but the apparatus for eifecting this does not form edge. On the other hand the part of the plunger ,part of the present invention. which determines the end of the injection period What I claim as my invention and desire to is then constituted byv a groove‘, edge or the like secure by Letters Patent is: ‘ . which is not inclined, but lies in a.v plane normal 75 1. A sleeve valve internal combustion engine 2,318,333 ~ operating on the two-stroke cycle comprising in 3 combination a cylinder, a piston. therein, cir 'thereof as spray in the form of a hollow cone‘ \ cumfer‘entially spaced ports in the wall of the whose axis is substantially coincident with the cylinder and in the sleeve valve which are un cylinder‘ ‘axis, the diameter of this spray cone covered by the piston towards the end of its out where it passes through the mouth of the com- ‘ stroke, means for delivering scavenge air through 5 . bustion chamber being‘ less than the minimum . these ports into the cylinder, said ports being so diameter of that mouth, at least one sparking constructed and arranged as to impart to the .> plug by means of which‘the fuel charge is always admitted air no substantial rotative e?ect, ports ignited, said plug being mounted in the said com in the wall of the cylinder through whichex- ' , bustion chamber, and a fuel pump delivering fuel haust gases ?ow, said last named ports being to the said injector with such timing that the uncovered by the inner end of the sleeve valve, ’ l cone of fuel spray will meet and mingle with the a combustion chamber in the head of the cylin ‘air entering the cylinder through the scavenge der, a fuel injector centrally situated in this com- ‘ ports during the latter part of the scavenging _ bustion chamber and which injects fuel into the period as set forth. cylinder from the inner end thereof. as spray in 3. A method of operating on the two-stroke the form of a hollow cone whoseaxis is substan cycle a sleeve valve internal combustion engine, tially coincident with the cylinder axis, at least . comprising the steps of admitting scavenge air one sparking plug by means of‘ which the fuel into the engine cylinder adjacent the outer end thereof in such manner as to establish no sub charge is always ignited, said plug being mounted 20 in the combustion chamber in the cylinder head, . stantial rotation of the air within the cylinder, f = discharging exhaust gases from the cylinder ad and a fuel pump delivering fuel‘to the said in,- ‘ jacent the inner end jector .with such timing that the cone of fuel‘. thereof, injecting fuel di-. and mingle with the air enter rectly into the cylinder and axially thereof from through the scavenge ports dur the inner end during the latter part of the scav ing thelatter part of the scavenging period as' 'enging period, and so as to cause the fuel to meet v set forth. and mingle with the incoming air, spark-igniting 2. A sleeve valve internal combustion engine the fuel, and varying the instant of initiation of operating on the two~stroke cycle comprising in ffuel injection in accordance with variation in combination a cylinden-a piston therein the face engine load without substantial variation in the of which is formed symmetrical about the cylin 30 instant of termination .of. injection. ' ' ' der axis, circumferentially spaced ports in the 4. A method of operating. on the two-stroke wall of the cylinder and in'the sleeve valve whic cycle a sleeve valve internal combustion engine. are uncovered by ‘ _ comprising the steps of admitting scavenge air the piston towards the end i ' into the engine its outstroke, means for delivering scavenge air 35 cylinder adjacent the outer end ~ into an air ‘belt around the cylinder and thence -‘ thereof in such manner as to establish no sub- to these ports, said ports being ‘so constructed stantial rotation of the air within the cylinder, and arranged as to impart to the admitted air discharging exhaust gases from the cylinder ad no substantial rotative e?ect, ports in the wall > ja‘cent the inner end thereof, injecting fuel di of the cylinder through which exhaust. gases ?ow, 40 rectly into the cylinder and axially thereof from " said last named ports being uncovered by the. the inner end during the‘ latter part of the scav inner end- of the sleeve valve, a combustion cham; - - enBing period,‘ so as to form a axially directed her having a bulbous‘ form which is a ?gure of hollow cone of spray, to ‘cause the fuel to meet revolution about the cylinder axis this chamber ' and mingle with the incoming air, spark-ignit - ing the fuel, and ya opening into thev end of the cylinder by way of 45 g the instant of initiation a mouth whose diameter is less than themaxi of fuel injection in‘ accordancewith variation in the chamber but more than engine load without ‘substantialvarlation half that diameter, a fuel injector centrally situ instant of termination of injection. . ated in this combustion chamber and which in feet; fuel into the cylinder from the ‘inner end so_ .HARRY RALPH RICARDO‘.