US 2278245 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
March 31, 1942- F. coLELL 2,278,245. 'i
INTERNAL COMBUSTION ENGINE ^OF THE COMPRESSION IGNITION TYPE Filed Feb.V 5, 1959 havo( T; iedvh-CO le,
Parente' Manci; 194?.`
',INTERNALCOMBUSTION ENGlNE Ortner;l x CoivIPnESSVIoNj-IGiSiTIIQNLTYBE i Richard iedrch eeil', dgiial'sto'; isiriinnr-v ham, EnglandgpassignontolThe-Austin Motor Company, Limited, Northfield, Birmingham,
A InyGreatzBritain February I5, 1938` selanaflcl. 10a-i141): Thev inventionr relates v:internal ,combustion Q engines ofthe Dieselor compression ignitionf type. Itis well known that sucheng'inesare sub-` ject to a defect,v known as Diesel Knock, caused apparently by combustion'delay, and with a view to avoiding orV lessening thisdefect` it has been proposed to arrange forY the vvin'jectiorlfof. a small quantity'of fuel prior to the main injection, thisv being known as apilot-'injection. It has been found that such an injection greatly lessens the effect of knock.
To effect such pilot injection', it has vipeenll'rfih-v posed to provide vtwofselzvaratek fuel injection* pumps delivering fuel to two separate nozzles and through two separate v-non-returnvalves, but
such arrangement involves the use of a large number of additional parts with .increasedv errpense and weight. It has also beenproposed to vprovide two fuel pumps'supplying f uel'to a com-` mon nozzle; but this does not `greatlysimplify the construction and necessitates a large volume of fuel between thepumps and thenozzle,'and` necessitates two non-return valves; It has also`r been proposed to provide only a single fuel rpumpV supplyingvfuel to a single nozzle;jbut this necessif- Ji tates the use of two operative surfacesona single cam which is unsatisfactory as it does-not.A leave` t sufficient time for two'i consecutive-injections and a pause between.v f g l According to this invention, two pump cylinderseach having a suction port are useda'main-pump cylinder for the main charge andra pilot pump cylinder for the pilot charge, and the two pumps are connected in such a wayvthat theorie pumpdelivers its charge through'the suctionjport of the other, fromwhere it flows -to the nozzle via the. non-return valve'. Thus there l 'is `afirst pump, fuel from which passes through the cylin-v the main pump.
The supply of fuel to the second pump cylinder passes through the delivery port of the rst pump cylinder, via the cylinder and suction-port of the i-lrst pump,v the piston of the latter pumpvbeing der of a second pump, but either of vthese` may be arranged to move forward just priorA to, or justV after, the forward movement of vthesecond'pisv ton, andL in such va way that the secondv piston can displace fuel backwards into thev suctionl chamber through the rst pump.
A convenient embodiment of .the inventionv is described .with reference to the drawing herewith which is a vertical section illustrating the fuel injection system of a compression ignition engine,
said system being arranged accordingto' the invention;l
,fuel injection' nozzle `B the 'nonqreturn l valve and eine main fueip'umpylinder' 11i-"whichfW'i'kS the main piston D" havingl a fladfE `the dium. kof a rollerjd 4turnably` mounted ,inl @slide 10 en, @integral wants-e piston. The 1arte-r is .alge provided-with a', ipair of rm's'j 'd4 werking in a pair-of's'lots' y' in a turnablefsfleeve'J which has, at yfits upper-end, spur teeth il-ve'n'gaging with/a .rackr j? moved: jby the l:engine governor, Vwhereby the vlatter'aots; .to rotate thehmainfpiston, all thesepartsbeingusual,practlcei Y V Kis thef cylinder of them-pilot. umpin which works the pilot "pistonnMhaving -a head m which also: has itsl lowerv edge vrof J helical form. Itf* also has agroove m1 connecting ,thespace above the frotatedfsl'milarlyas is the 'mainfpisjton'- by'arack Ythe medium offa roller q and doublefrarmed lever the pilot cylinder Kthrough` the-Wall thereof. SV is a second port'leading-from :the uppei'en'd of thepilot cylinder to themainlcylinder-,C v,also
through the wallthereof.
The operation is as follows; 1 The vpilot cam operatesv first .andgrockspthe lever q1 thus causing the pilot piston t'o'"inove upf.
'A5 the space above'it isfull offfuel, the pls'tonfat first` causes fuel to flow back -tothechamber''P'I `buty the piston head in advancing covers the-'port 1'1. when the fuel, having; no escapa-isfo'rced vlip throughthe port'S andv-thencethrough the main cylinder C to the-nonreturn: valve B and so. to
the fuel ,nozzlev in the .engine cylinder (not shown). As soon as the bottoni edge of thefhead of the piston' M passes the bottoin'of- .theport' the pilot injection is ,finishedand fuercan flow back via the groove m to the chamber-P. v"Mean-- time, the cam .F' has commencedv to raise the main vpistonDand its head E movesto close the port S; but since the head of the piston M has reopened the port R, the piston D can, at first, re-
turn fuel through the ports S and R to the chamber P. As soon, however, as the head E closes the port S, the fuel cannot flow back, and therefore, further movement of the main piston forces fuel past the non-return valve for the main charge. As soon as the bottom edge of the head E passes the bottom of the port S, the main in- .lection is finished, and the fuel can flow back to the chamber P via the port e, cylinder K and port R, this latter being still open. Each piston head in passing back over its respectiveport will cause a certain amount of vacuum in the space above; but this will be rapidly filled up as soon as both piston heads reopen the4 ports of `their respective cylinder.
It will now be clear that the cylinder K may, if desired, be the larger cylinder and act as the main pump cylinder, but in such case the other y piston then acting as the pilot piston, must be that which moves forward first, the cams being,r
so placed as to conform to this condition.
Having fully described my invention what I `claim and desire to secure by letters Patentfis:
1. In a fuel injection apparatus for use` with an engine of the compression ignition type, the combination' of a fuel port, a non-return valve for the fuel port, a main fuel pump cylinder, a main piston working therein, a pilot pump cylinder, a pilot piston working therein, a fuel supply chamber Acommon to the aforesaid main fuel pump cylinder and pilot pump cylinder, each of said cylinders having a suction port, each cylinder also havinga delivery port, the pilot pump cylinder being positioned in proximity to and in communication with the main fuel pump cylinder, said cylinders being alternately in communication with the aforesaid fuel supply chamber with which the aforesaid suction ports communicate, whereby the piston ofthe one cylinder first causes fuel to flow back in to the common fuel supply chamber, fuel being then forced to the other cylinder through the suction port thereof V'and from said cylinder to the non-return valve and so to the fuel port in the engine cylinder.
l2. In a fuel injection apparatus for-v use withpiston working therein, a pilot pump cylinder, a pilot piston working therein, each cylinder having a suction port, a fuel supply passage alternately in communication with the suction port ofthe pilot pump and with the main fuel pump cylinder, either of the aforesaid pumps may deliver its charge to the other pump cylinderthrough the suction port thereof, said fuel passing thence to said non-return valve, the fuel passing to said other pump cylinder and destined to be pumped by the piston of said other cylinder passing from said fuel supply chamber through said suction port of said first named cylinder and Working therein, va pilot pump cylinder ana a pilot piston working therein, the pilot-pump cylpump cylinder through the suction port thereof,
said fuel passing thence to said non-return valve whereby fuel passing to said main pump cylinder and destined to be pumped by .the main piston passes from said fuel supply chamber through said-suction port of the pilot pump cylinder and thence through such cylinder and the suction port of the main pump cylinder and whereby during the part of the forward stroke of the said main piston fuel can flowl back to the aforesaid fuel supply chamber via the pilot pump cylinder.
3. In a fuel injection apparatus for use with an engine of the compression ignition type, the combination of a fuel p ort, a non-return valve for said port, a. main fuel pump cylinder, a main inder being positioned in proximity to the main pump cylinder, a common passage forming the outlet from Ithe one pump cylinder and the inlet to the other pump cylinder, an outlet passage from said other pump cylinder leading to the non-return.valve, a fuel supply chamber and a .passage leading therefrom tothe said one pump cylinder, whereby the on pump piston may, at each operation, draw a charge of fuel from said chamber and force it through the other pump cylinder tothe non-return valve, and whereby said other pump piston mayat each operation, draw a charge from the said one pump cylinder and, during the rst part of its forcing stroke, return a portion of the fuel to the supply chamber backthrough said one pump cylinder and Y during the latter part of-itsstroke force another portion of the fuel to the non-returnvalve.
5. In a fuel injection apparatus for-use with anengine of the fuel injection type having, in respect of each engine cylinder, afuel injection port and a non-return fuel valve, thecombination of a main pump cylinder and a main piston working therein, a pilot pump cylinder and a Vpilot piston working therein, the pilot pump cylinder being posiioned in proximity to the main pump cylinder, a common passage forming the outlet from thepilot pump cylinder and the inlet to the main pump cylinder, an outlet passage from the main pump cylinder leading to the nonduring the first partof its forcing stroke, return a .portion of the fuel to the supply chamber back through said pilot pump cylinder and during the latter part of its stroke forcel another portion of the fuel to the non-return valve.
RICHARD FRIEDRICH COLELL.