US2420550A - Liquid fuel injection apparatus - Google Patents

Description

May 13, 1947. R. MILLER LIQUID FUEL INJECTION APPARATUS Filed Oct. 20, 1942 2 Sheets-Sheet 1 l I z 1 I I l I l I I l I l l l I l l l l l l I a '1 INVENTOR Ralph Mil/er Anomv May 13, 1947. R. MILLER LIQUID FUEL INJECTION APPARATUS Filed Oct. 20, 1942 2 Sheets-Sheet 2 INVENTOR Ra/ h Mil/er A'rro Y Patented May 13, 1947 LIQUID FUEL INJECTION APPARATUS Ralph Miller, Bufialo, N. Y. Application October 20, 1942, Serial No. 462,673

7 Claims.

This invention relates to liquid fuel injection apparatus.

An object of the present invention is to provide improved fuel injection apparatus for use in high power internal combustion engines, adapted to provide correctly atomized fuel in metered quantityduring the short duration of injection existing in engines especially of the high speed, high output type.

A further object is to provide an apparatus as aforesaid in which the valve mechanism of the injector nozzle is acted upon, in a desired manner, in both an opening and closing direction, by liquid under pressure from a common source of supply.

Other and further objects of the invention will appear from the following description, the accompanying drawings and the appended claims.

Referring to the drawings forming a part of this application, Figure 1 is an elevation of a preferred embodiment of the fuel injection apparatus of the present invention, the injector nozzle and a metering valve being shown partly in axial section, a part being broken away, part of a cam shaft mechanism forming part of an internal combustion engine also being shown, partly in transverse section; Fig. 2 is a view similar to Fig. 1, showing another embodiment ,of the invention, parts beingbroken away; Fig. 3 is an elevation, partly in axial section, of an injector nozzle and metering valve unitary structure; :and Fig. 4 is a section on the line IV-IV of Fig. 1, parts being broken away.

Referring to Fig. 1 of the drawings, the fuel injection apparatus of the present invention, indicated generally by the reference numeral l, includes a source of fuel supply 2, a metering valve 3, and an injector nozzle 4. The source of fuel supply 2 is indicated diagrammatically and may be any conventional apparatus adapted 'to supply fuel under constant pressure to a delivery pipe 5 which is branched to extend from the source 2 to the metering valve and to the injector nozzle, as will later more fully appear.

For examp1e,the source 2 may be a pump-drawing fuel from a fuel tank (not shown) and pumping it through pipe 5, the pump being provided with means (not shown) for regulating the delivery pressure. It is contemplated that a'single source 2 will provide for all the injector nozzles and metering valves of an engine, there being an with branches for each of the nozzles and metering valves.

The metering valve 3 includes a hollow base 6 adapted to be secured to an appropriate part of the engine over a cam shaft 1 and cam 8, the cam having a cam face 8a. The cam engages a roller 9 journalled to a crosshead Ill which slides vertically in the hollow interior of base 6. A housa cap l3, secured on top of the housing by a threaded connection, and open at the bottom to the interior of the base 6.

A reciprocating valve element i4 is disposed in the cylinder l2, its upper end being spaced from cap [3 and its lower end extending into the interior of base 6 and resting on top of crosshead ID. A coil spring l5, disposed in the cylinder i2 and compressed between the cap l3 and element l4, holds the element in engagement with the crosshead iii. The top of the element i4 is reduced to provide a spring retainer iii. A vent I1 is formed in the cap I3 and opens into the top of the cylinder 12.

Element II has a reduced portion l8 intermediate its ends, providing a chamber l9 defined by the reduced portion It, the adjacent portion of the wall of the cylinder H, a horizontal transverse shoulder 20 on the element at the upper edge of the reduced portion T8, and a curved transverse shoulder 2l on the element at the lower edge of the reduced portion l8. The shoulder 21 has two identical portions, one on each side of a diameter of the element. Each portion has a central high point from which point the portion curves downwardly on either side thereof.

Ports 22 and 23 are formed in the housing wall,

port 22 being in continuous communication with chamber I9 and port 23 being adapted to open into the chamber i9' when element I4 is in lowered position. When the metering valve is adjusted for maximum fuel injection the high points of the shoulder 2| will be on the same diametrical plane of cylinder 12 as the port 23, as shown in Fig. 1.

Two other ports 24 and 25, below ports 22 and 23 respectively, are formed in the housing wall. Element M has another reduced portion 26, spaced below portion l8, providing achamber 21 with which port 24 is in continuous communication and into which port 25 is adapted to open when the element I4 is in raised position. Chamber 2'! is defined by the reduced portion 26, the adjacent portion of the wall of cylinder l2, a horizontal transverse shoulder 28 on the element at the lower edge of the reduced portion 26, and a curved transverse shoulder 29 on the element at the up- 3 per edge of the reduced portion 26. Shoulder 29 is parallel to shoulder 2|, as is clearly shown in Fig. 1. The portion of the element between shoulders 2| and 29 forms a cut-off valve membe 30 for closing port 23 instantaneously with opening of port 25, or vice versa.

Port 23 is formed by a bore extending across cylinder l2 so that there is a port 23a diametrically opposite port 23. Ports 23 and 23a are connected by a U-shaped passage 231), best shown in Fig. 4, and formed by three bores closed at their outer ends by plugs. Port 25 is similarly made with a port 25a and passage 25b. Thus,

when element I4 is in raised position, with valve member 36 closin both ports 23 and 25, oil under pressure in port 23 fills passage 23b and port 23a, and oil under pressure in port 25 fills passage 25b and port 25a, balancing the action of the oil under pressure on the element l4, thereby preventing an unbalanced lateral force thereon. Similarly, when element I4 is in lowered position, as shown in Fig. 1, oil under pressure in port 25 is balanced by oil under pressure in port 25a. Ports 23a and 25a are controlled by the shoulders 2| and 29 similarly to ports 23 and 25.

Element I4 is rotatable for adjustment to vary the timing of opening and closing of the ports 23-2311 and 2525a and to thereby vary the duration of the injection period. The adjusting mechanism, indicated generally by the numeral 3|, is of substantially conventional design and will therefore be briefly described. It includes a gear 32 mounted in the housing H and supported by the base 6 against vertical movement and having depending spaced lugs 33 providing guideways for guides 34 on the element l4. In the present instance the guides 34 are shown as square-headed studs pressed into holes formed in the element. This permits axial movement of the element |4 relative to the gear 32 while insuring rotative movement of the element with the gear 32. Gear 32 is in mesh with a rack 35 which may be manually operated or operated by a governor (not shown), in a well-known manner, to rotate the gear and element for varying the opening and closing of the ports as aforesaid.

The injector nozzle 4 is adapted to be secured, in the usual manner, in a bore in a cylinder head of the internal combustion engine and to project therethrough opening into a cylinder thereof, the cylinder and cylinder head not being shown. The nozzle 4 includes a hollow housing 36 open at the bottom and closed at the top by a head 31 which is threaded partially into the hollow interior of the housing 36, thereby providing a chamber 38 below the head 31. A nozzle member 39 is disposed in the chamber 38 and extends through the bottom of the housing 36 and exteriorly downwardly therefrom. It is supported by means of shoulder 40' and 4| formed respectively on the housing 36 and nozzle membe 39.

A spacer or washer 42 is disposed between the top of the member 39 and the bottom of head 31, head 31 being screwed tightly against the washer 42 thereby holding the member 39 tightly in the housing.

The member 39 has injection jets 43 adapted to open into the engine cylinder. These injection jets open into a bore 44 provided at its upper end with a port or valve seat 45. An injection fuel chamber 46 is formed in the member 39 above the valve seat 45 and one or more fuel passages 41 (one being shown) open into cham-' ber 46 and extend upwardly therefrom to an annular groove 48 formed in the upper face of the member 39. An annular groove 49 is formed in the upper face of the washer 42 and is connected to the groove 48 by one or more fuel passages 50, one being shown.

A passage 5| formed in the head 31 opens at its lowe end into groove 49 and extends upwardly through the head and opens through the outer face of the head. A chamber 52 is formed in the head adjacent the washer 42. A passage 53, formed in the head, opens at its lower end into chamber 52 and extends therefrom upwardly through the head and opens through the outer face of the head. Washer 42 has a central orifice 54, which opens at the top into chamber 52 and which is tapered at the bottom providing a seat 54a diverging toward a cylinder 55 formed axially in the member 39, the cylinder 55 opening at its lower end into chamber 46.

A needle valve 56 for coaction with seat 45 is disposed in chamber 46. A pressure-responsive plunger 51 is disposed in cylinder 55 and is. formed integral with valve 56. Valve 56 is of a smaller diameter than plunger 51 providing a shoulder 58. The upper end of plunger 51 is spaced from seat 54a, when the valve is closed, providing a chamber 59 and permitting a small axial movement of the plunger 51, as will later be more fully described, to raise valve 56 oil seat 45. As chamber 59, orifice 54 and chamber 52 are in continual communication they combine to form a loading fuel chamber. A stem 60 is disposed in orifice 54 in spaced relation with the wall thereof, and extends into chamber 59, and is formed integral with plunger 51. The stem 60 is of smaller diameter than plunger 51 providing a shoulder 6|. The upper end of stem 60 is disposed in chamber 52. A spring seat or washer 62 is supported on top of stem 60, and a coil spring 63 seats on this washer and is compressed between the washer and the opposite top wall of chamber 52. Washer 62 is of less diameter than chamber 52.

Plunger 51 is of the same diameter throughout so that throughout its travel it is afiected only by pressures in chambers 46 and 59. When the apparatus is in the position shown in Fig. 1, that is to say, when the cam 80. is not in engagement with roller 9, the pressure in chambers 46 and 59 is similar and no leakage past plunger 51 can occur. During injection,.when the pressure in chamber 46 is the higher, plunger 51 will be in engagement with the tapered seat 54a, closing orifice 54, and preventing leakage past plunger 51 and any resulting drop in pressure in chamber '46. The engagement of plunger 51. and seat 54a is line engagement, so that the full top surface of the plunger 51, i. e., the shoulder 6| and top of stem 60, is subject to the pressure prevailing in chamber 52.

Delivery pipe 5 has a branch 64 connected to port 22 and a branch 65 connected to passage 5|. If desired pipe 5 could go directly to either of these ports and a separate pipe go from the source 2 to the other port. A branched pipe 66 is connected at one end to passage 53 and extends through one branch 61 to port 23, and through another branch 68 to port 25. A pipe 69 is connected at one end to port 24 and at the other end opens to'the exterior of the fuel injection apparatus to the atmosphere or to a place of low pressure, for instance to the fuel supply tank (not shown).

The operation of the fuel injection apparatus is as follows: Fuel injection chamber 46 is in continuous communication with source 2 as aforeby the needle valve 56.

said so that fuel is maintained in chamber 46 at'a. constant pressure. This is true regardless of the operation of the metering valve. As shown in Fig. 1, the metering valve is in a position wherein needle valve 56 closes bore 44. At such time fuel under constant pressure from source 2 fills pipe'5,

port 22 (through branch 64), chamber I9, port 23, pipe 66 (through branch 61), passage 53, chamber 52, orifice 54, and chamber 59. Thus fuel under the same pressure acts on both shoulders ofplunger 51. However the fuel above plunger 51 acts on surfaces equal to the entire cross-sectional area of the plunger 51 (the pressure faces of shoulder 6| and stem 60), whereas fuel below plunger 51 acts on a lesser area, (the pressure faces of shoulder 58 and the portion of valve 56 in chamber 46), this latter area being smaller by the area of the bore 44 and seat 45. Thus the total fuel pressure holding the needle valve 56 closed is greater than the total fuel pressure acting to open same. Furthermore, the needle valve 56 is urged downwardly by the additive force of spring 63. Port 25 is closed from port 24 by valve member 30 as element I4 is in its lowermost position, as shown in Fig. 1.

The rotation of cam shaft I in the direction of the arrow 41 brings cam face 811 into engagement with roller 9, lifting crosshead I and element l4. Shoulder 2| closes ports 2323a instantaneously with the opening of ports 2525a by shoulder 29. As port M is opened to a place of lower pressure than the pressure of the fuel on shoulder 6| and stem 66, this latter pressure immediately drops, for instance to atmospheric pressure. However, as chamber 36 is in continuous communication with source 2 the pressure is maintained below .the plunger 5i, and this pressure exerts a force.

sufficiently greater than the force of the reduced pressure on shoulder 6|, stem 60 and that of spring 63 to force the plunger 51 and needle valve 56 quickly upward, further compressing the spring 63. Bore Mi is thereby opened to chamber 46 and injection through jets 43 follows. Due to the quick opening of bore M; and to the available supply of fuel under high pressure in chamber 16, only correctly atomized fuel is injected through jets 43 at the beginning of injection and no starting dribbling of fuel occurs.

. Injection continues until element l4 moves downward sufficiently for shoulder 29 to close ports 25-25a and shoulder 2| to open ports 23 2311, once again opening chambers 59 and 52 above plunger 5! to the full pressure of the fuel in source 2.

When the needle valve is in raised position immediately after opening of ports 23-4311, the effective fuel pressures urging the plunger down- 'ward and urging the plunger upward are balarea acted upon in a valve-opening direction then being the entire pressure face of valve 56 and the pressure face of shoulder 58. Only the spring 63 now exerts an efiective force forcing the plunger 51 downward. However, as the needle valve 56 approaches the seat 45 the efiective fuel pressure urging the plunger 51 upward is reduced, due to the throttling action as bore 44 is being closed, resulting in an increase in the effective fuel pressure force urging the plunger 51 downward, augmenting the force exerted by the spring 63, and efiecting quick closing of bore 44 This quick closing insures complete atomization of the fuel to the end of the injection period, preventing dribbling of fuel into the cylinder and thereby preventing the accompanying undesirable injection conditions caused by such dribbling, as will later more fully appear.

A modification of the invention is exemplified by the fuel injection apparatus shown in Fig. 2, and indicated generally by the reference numeral 10. The apparatus differs from the apparatus I only in the metering valve and parts for operating same, the source of supply and the injector nozzle being the same as in Fig. 1, and where referred to, reference will be had to Fig. 1, similar reference numerals being employed.

The metering valve is indicated by the numeral 1|. It includes a housing 12 having in its upper portion .a central bore providing a chamber 13,

and an axial bore of smaller diameter than the just below the seat 16 opening into the cylinder 14. Another port 18 is formed in the housing wall below port Tl, also opening into the cylinder 14. A port 19 is formed in the housing wall opposite and opening into chamber 13. Chamber i3 is closed at the top by a two-pieceplug and cap device secured to the housing 12 by a threaded connection.

A valve member 8| is disposed in chamber 13 for coaction with seat 16. A stem 82, formed integral with the valve member is disposed in the cylinder 14, its lower end being above port 18. A balancing portion 83, integral with valve member 8|, extends upwardly therefrom into a recess 83a formed in the plug of device 80, the portion 83 reducing the surface on top of member Bl upon which oil under pressure in chamber i3 can work. Recess 83a is vented to the atmosphere. The stem 82 is reduced just below the valve mem ber, providing with the opposite portion of the defining wall of cylinder it, a chamber 84 in continuous communication with port Ti. A coil spring 85 disposed in chamber 13 and compressed between the plug of device 89 and a washer supported on valve member 8|, exerts a force urging valve member 8| toward seat 16. An axial'bore 86 extends through the stem 82, valve member 8| and partially through portion 83, tak- A rod 81 is disposed in cylinder 14 below stem 62, its upper end being adapted to engage stem 82 and its lower end extending below housing 12 and engagin a wedge 88 pivoted to an arm 89 extending from a shaft 90; which may have its bearings (not shown) in any suitable part of the engine. In a multi-cylinder engine, wedge 85 may be wideenough to extend under all of the metering valves. Wedge 88 may be adjusted manually or automatically, as desired, and have means (not shown)- for holding it in an adjusted position.

Rod 81 is reduced adjacent port 18, providing a chamber 9| in continuous communication with port 18, chamber 9| being defined by the reduced portion of rod 81, the opposed portion of the cylinder wall,- a portion of the bottom of stem 82 and the shoulder formed by the juncture of the reduced portion andthe rest of the rod 81. Rod 81 7 chamber 13. The top wall of rod 81 forms a valve member 92 for controlling the opening and closing of bore 86 to chamber 9|.

The mechanism for operating the valve 1| further includes a cam shaft 93, a cam 94 thereon having a cam face 944:, and a rocker arm 95 pivotally supported on a shaft 96, which may have its bearings in any suitable part of the engine. The rocker arm bears at one end, by means of a roller 91, on cam 94 and at the other end engages the under face of wedge 88. A coil spring 98, supported on a seat 99, which may be on any suitable part of the engine, and bearing against a cap I88, which in turn engages the rocker arm ,95 beneath wedge 88, exerts a force upwardly on the part of the rocker arm engaging wedge 88, the spring thereby keeping the arm in engagement with cam 94 and wedge 88 in engagement with rod'81. When cam face 94a engages roller 91, spring 85 moves valve member 8|, stem 82 and rod 81 downward until valve member 8| engages seat 16. Thereafter rod 81 descends relative to stem 82, the pressure of the oil in bore 86 acting against valve member 92.

The source 2 is connected to passage of nozzle 4 and to port 11 of valve 1| by a branched pipe I8I similar to pipe 5 of Fig. 1, there being a branch I82 connected to passage 5| and a branch I83 connected to port 11. A pipe I84 similar to pipe 69 of Fig. 1, and for a similar purpose, is connected to port 18. A pipe I85 connects port 19 with passage 53 of nozzle 4.

' The apparatus of Fig. 2 is shown in the sameoperative position as the apparatus of Fig. 1, namely, just before injection. Further rotation of cam shaft 93 in the direction of arrow b will raise roller 91 and compress spring 98-, permitting rod 81 to drop until valve member 8| seats on seat 16 and to further drop until bore 86 is opened to chamber 9|. When this happens, pipe I84, chamber 9|, bore 86, chamber 13, pipe I85 and passage 53 of nozzle 4 will be in communication, effecting a drop in pressure on top of shoulder 6| and stem 68 (of nozzle 4). As source 2 is in continuous communication with chamber 46 of nozzle 4 through branch I82 of pipe I8I, injection will occur the same as in the apparatus of Fig. 1. When cam face 94a leaves roller 91, spring 98 forces rod 81 upward closing bore 86 and raising stem 82 until valve member 8| leaves seat 16. Source 2 will then be in communication through pipe I8I with-both passages 5| and 53 of nozzle 4, communication with passage 53 being through port 11, chamber 84, chamber 13, and pipe I85.

Adjustment of the metering valve 1| is effected by moving wedge 88. Assuming the position in Fig. 2 is for maximum fuel injection, and it is desired to lessen the quantity of fuel injected, it

is only necessary to move wedge 88 to the left as viewed in Fig. 2. This will effect a further movement upward of rod 81 and stem 82 (the cam 94 remaining in the position shown) and will therefore retard the time atwhich rod 81 opens bore 86 to chamber 9|, or, in other words, will retard the beginning of injection. Similarly it will hasten the termination of injection the same amount that it retards beginning, so that the injection period will be shortened.

The fuel injection apparatus shown in Fig, 3, indicated generally by the reference numeral I86, is similar to the apparatuses I and 18 in that it has three parts, the parts being the source of fuel supply (not shown in Fig. 3), the metering valve I81 and the injector nozzle I88, the valve I81 and nozzle I88 being secured together and having common parts, thereby forming a unit injector indicated by the numeral I89. Apparatus I86 is for employment in engines having an overhead cam shaft (not shown), as will presently appear.

Injector I89 includes a hollow body II8 on which is threaded, at the bottom thereof, a cap III fora purpose presently to appear. Body I'I8 has at its top a central chamber II2, therebelow another chamber II3 of lesser diameter and therebelow an axial bore providing a cylinder I I4 of lesser diameter than chamber II3, there being a shoulder II5 between chambers II2 and H3 and a shoulder II6 between chamber H3 and cylinder II4.

Cap III is hollow providing a chamber II1 between its bottom wall H8 and the bottom of body II8. A central orifice H9 is formed in wall H8, and being of lesser diameter than chamber 1, provides a shoulder I28 therebetween.

A valve element I2I is disposed in cylinder H8, chamber [I3 and chamber II2. A washer I22 is secured to the upper end of element I2I by a split snap ring I23, and washer I 22 supports a crosshead or sleeve I 24, which engages the top of element I-2I and is adapted to reciprocate in chamber II2 and to be acted upon by a rocker arm of an overhead cam shaft mechanism (not shown). An orificed washer I25 is supported on shoulder I I5, fitting freely around element I2I, and a coil spring I26 is compressed between washers I22 and I25, urging element I2I upward and holdin sleeve I24 in engagement with the rocker arm (not shown) in a well-known manner,

Apparatus ,I86includes an adjusting mechanism, indicated generally by the reference numeral I21, which is substantially like the mechanism 3I of Fig. 1 and therefore it will be but briefly described, using the same numerals as in Fig. 1 with an accent added. Mechanism I21 includes a gear 32 having upwardly extending spaced lugs 33. Gear 32 is supported on shoulder H6 and fits freely around element I2I. Guides 34' formed integrally with the element I 2| slide in the guideways formed by the lugs 33. A rack 35 meshes with gear 32'.

The port-controlling part of element I2I is similar to the corresponding part of element It (Fig. 1), taking into consideration that in Fig. 3 the cam operates from the to and therefore it will be but briefly described, using the same numerals as in Fig. 1 with an accent added. There are reduced portions I8 and 26; shoulders 2| and 29'; shoulders 28 and 28; and chambers I9 and 21'. There is further an axial bore I28 extending from the bottom face of element I2I to the reduced portion 26' and opening into the chamber 21' by means of a radial bore I29. The bottom face of element I2I is spaced from the bottom of the body 'I I8 providing a chamber into V which bore I28 opens at its lower end;

Nozzle I88 is, in the main, similar to nozzle member 39 of Fig. 1. It has a portion disposed in chamber I I1 and resting on shoulder I28, the remainder of the nozzle extending through orifice H9 and therebeyond.

A washer or spacer I38 is disposed in chamber I I1 between the nozzle I88 and bottom of the body II8. Washer I38 is shown made in two pieces but it may be made in one piece if desired.

Nozzle I88 has jets I3I, a bore I32 communicating therewith, a port or valve seat I33 at the upper end of the bore, an injection fuel chamber needle valve I38 supported on seat I33 for action therewith, and a plunger I39 integral with valve I38 and disposed in cylinder I31 in spaced relation at its upper end with washer I30, washer I30 having a. recess for a spring providing, with the space in cylinder I31 above plunger I39, a loading fuel chamber I40. A coil spring MI is disposed in chamber I40 and compressed between the top of the plunger I39 and a'washer I30 acting to force plunger I39 downward. The lower end of the recess is flared, providing a tapered seat I42 for the same purpose asseat 5411 (Fig. 1). As aforesaid, washer I30 is made in two pieces, the lower piece I44 being provided with the seat I42. A shoulder I43 is provided between valve I38 and plunger I39. A dowel I45 secures body III) and the top piece of washer I30 against relative rotation. V

A short groove I46, formed in the upper face of washer I30. is connected by a passage I41 to chamber I40, and another short groove I48, also formed in the upper face of washer I30, but spaced from groove I46, is connected by a passage I49 to groove I36, passage I49 including a bore Mite in the top piece of washer I30, a, groove I492) in the top face of piece I44, and two bores I490 connecting grooves I49! and I36.

The body H0 has formed therein a plurality of passages, as will presently appear. These passages may be formed by boring and are so shown in the drawing. Outer ends of some of the bores are closed by plugs I50 in a well-known manner.

A passage II is formed in the wall of body lit, opening therethrough adjacent the mechanism I21 and extending downwardly through the body to a point adjacent chamber I3, where it is branched, a branch I52 opening into groove I48, and a branch I53 opening into chamber I9. Passage I5I is connected by a pipe (not shown) to a source of fuel supply (not shown) similar to source 2 of Fig. 1, the pipein this embodiment not being branched.

A passage I54 is formed in the wall of body I I0, opening therethrough below mechanism I21 and extending to chamber 21'. Passage I54 is connected to a place of low pressure similar to port' 24 in Fig. 1. As is clearly shown in Fig. 3,

passage I54 is U-shaped, passing through cylinder II4 twice (in opposite, directions). An annular groove I55 is formed in the body IIO around cylinder I I4 and in communication with passage I54 (forming a part thereof) so' that the {upper portion of valve element I2I will not stop the flow through passage I54 and so that oil in groove I55 will lubricate element I2I.

The body includes another branched passage I56, opening at its lower end in groove 146 and having a branch I51 adapted to open into chamber I9 and a branch I58 adapted to open in chamber 21. Branches-I51 and I58 are made similar to ports 23 and (Fig. 1) for balancing lateral oil pressure forces on the element I2I. A valve member I59, formed by the portion of element I2I between shoulders 2I' and 29' controls the opening and closing of branches I51 and I58, as will presently appear.

The operation of the apparatus of Fig. 3 is as follows: Fuel under pressure from the source of fuel supplypasses through passage I5I, which is the only passage in direct communication with the source. Passage I5I is in continuous com munication with the source and with branch I52, groove I48, passage I 49, groove I36, passages I35 and chamber 134. Thus fuel, under constant pressure is continuously in chamber I34, for injection and for exerting a lifting force on plunger I39. Branch I53 opens continuously into chamber I9 which therefore is in continuous communication with the source of fuel supply.

Valve element I2I is shown in Fig. 3 adjusted for maximum fuel injection. Element I2I is in full raised position, with chamber I9 in communication with branch I51. Thus fuel, under the pressure of the source of fuel supply, fills.

chamber I40 and acts on top of plunger I39, chambe I40 being in communication with branch I51 through passage I4I, groove I46 and passage I56. Branch I58 is closed by valve member I59 of element I2I. Therefore the pressure of the fuel acting on shoulder I43 and-on top of plunger I39 is the same and plunger I39 is held downward, as the fuel under pressure in chamber I40 acts on a greater surface of plunge I39 than the fuel under pressure in the chamber I34, as in the nozzle of Fig. 1, and the spring I4I augments this closing pressure.

Downward movement of element I2I by the cam shaft rocker arm mechanism (not shown) acting on sleeve I24, effects closing of branch I5? simultaneously with opening of branch I58. Pressure in chamber I40 is thereby reduced as it is connected to the atmosphere or some place of low pressure by means of passage I41, groove I46, passage I56, branch I58, chamber 21, and passage I54. Pressure in chamber I34 then lifts plunger I39 and effects injection, which continues until the cam shaft mechanism permits element IZI to rise, due to the action of spring I26, to a position opening branch I51 to chamber I9. During downward movement of element I2 I. the space below element I2! is vented, preventing pressure rise therein, through bores I28 and I29, chamber 21 and passage I54.

It will be seen that the operation of the apparatus of Fig. 3 is substantially like that of Fig. 1 and no further description thereof is deemed necessary.

It will be seen from the foregoing description of three embodiments-of the present invention. that'the functions and ends attained by each of these embodiments are the same, and that therefore the advantages sought from the present invention are common to all three embodiments.

More specifically, in each embodiment the injection fuel chamber is in continuous communication with a source of fuel supply delivering fuel at a constant pressure. By constant pressure is meant that the source of fuel supply delivers pressure may be lower than at high output or high speed, and the source'of fuel supply may have automatic adjusting means for accomplishing actuating plunger, and works on a greater surface, when the valve is closed in a valve-closing direction so that the valve is hydraulically held closed and hydraulically actuated in a closing direction. This hydraulic feature is augmented by a coil spring urging the plunger in a closing direction. While the fuel actuating the plunger in a valveclosing direction is at a constant pressure, it is alternately in communication with the source of fuel supply and with the atmosphere or place of low pressure, so that its action upon the plunger isintermittent.

As previously described in relation to the operation of the apparatus of Fig. 1, but now describing all three embodiments, the nozzle valve is initially moved in a closing direction by the coilv spring, until the pressure of the fuel acting to move the plunger in a valve-opening direction is throttled. Thereafter, the pressure of the fuel acting to move the plunger in a valve-closing direction predominates, this latter pressure and the coil spring effecting a quick, sharply defined termination of injection, preventing dribbling of fuel into the cylinder, and thereby preventing the consequential poor combustion features common where dribbling occurs. Dribbling is prevented, as aforedescribed, at the beginning of injection by the constant high pressure fuel in the fuel injection chamber and by the quiclg raising of the valve of the injector nozzle.

In former injection apparatus, where it has been attempted to sharply terminate injection when the engine is running at high output, pressure surgesffhave occurred in the fuel delivery line, and these surges often result in a reopening of the injection valve at a Wrong time, and in a breaking of pipe line connections. These surges are produced by the high frequency intermittent pressures occurring in the lines between the inj ection pump and nozzle and is greatly augmented by the restriction in size of injection fuel passages, pipes and chambers, such restriction being required where the fuel pressure acting to open the injection valveQisQntermittent. In accordance with the preseiitinvention, injection fuel passages, pipes and chambers need not be restricted, but, on the other hand, because they are filled with fuel under constant pressure, may be made large enough so that pressure surges are not set up. Thus after injections and pipe breakage are prevented.

While there have been hereinbefore described approved embodiments of this'invention, it will be'understood that many and various changes and modifications in form, arrangement of parts and details of construction thereof may be made without departing from the spirit of the invention and that all such changes and modifications as fall within the scope of the appended claims are contemplated as a part of this invention.

The invention claimed and desiredto be secured by Letters Patent is:

1. Liquid fuel injection mechanism comprising a housing having a longitudinal-cylinder for a plunger, a fuel chamber opening into said cylinder at one end thereof and having an opening opposite said cylinder providing a valve seat, and a passage opening into said chamber for directly and continuously supplying injection fuel under pressure thereto; a plunger mounted in said cylinder for free sliding movement having an end, including a shoulder, adjacent said chamber, and a stem extending therefrom terminating in a valve for said seat, said end providing a fuel pressure surface, the opposite end of said plunger 12 being adjacent the opposite end of said cylinder and providing a dual element serving as both a fuel pressure surface and a valve, said housing further having a seat element at said opposite end of said cylinder for said dual element and engaging with the peripheral edge of the adjacent end of said plunger and a fuel passage opening through said'seat element for alternate transmission and release of fuel pressure respectively to and from said dual element, said duel element being closed when said stem valve is open, said dual element pressure surface, when said dual element valve is closed, being at least equal in effective pressure area to the effective pressure area of said plunger shoulder-stem end when said stem valve is open;

- and a spring urging said dual element from said seat element, said plunger operating to control said stem valve through cooperation of said spring and the pressures of said fuel upon said surfaces.

2. Liquid fuel injection mechanism comprising a housing having a longitudinal cylinder for a plunger, a fuel chamber opening into said cylinder at one end thereof and having an opening opposite said cylinder providing a valve seat, and a passage opening into said chamber for supply ing fuel under pressure thereto; a plunger mounted in said cylinder for free sliding movement having an end, including a shoulder, adjacent said chamber, and a stem extending therefrom terminating in a. valve for said seat, said end providing a fuel pressure surface, the opposite end of said plunger being adjacent the opposite end of said cylinder and providing a duel element serving as both a fuel pressure surface and a valve, said housing further having a seat element at said opposite end of said cylinder for said dual element and a fuel passage opening through said seat element for alternate transmission and release of fuel pressure respectively to and from said dual element, said last mentioned passage including a chamber spaced from said seat element, and said dual element including a shoulder and a stem extending into said last mentioned passage and terminating in a spring seat in said passage chamber; and a compression spring in said passage chamber supported on said spring seat, urging said dual element shoulder from said seat element, said plunger operating to control said stem valve through cooperation of said spring and the pressures of said fuel upon said surfaces.

3. Liquid fuel injection mechanism comprising a housing having a longitudinal cylinder for a plunger, a fuel chamber opening into said cylinder at one end thereof and having an opening opposite said cylinder providing a valve seat, and a passage opening into said chamber for directly and continuously supplying fuel under pressure thereto; a plunger mounted in said cylinder for free sliding movement having an end, including a shoulder, adjacent said chamber, and a stem extending therefrom terminating in a valve for said seat, said end providing a fuel pressure surface, the opposite end of said plunger being adjacent the opposite end of said cylinder and'providing a dual element serving as both a fuel pressure surface and a valve, said housing further having a seat element at said opposite end of said cylinder for said dual element engaging in a line contact with outside peripheral end edge of said 'plunger and a fuel passage terminating in a chamber adjacent to. and opening through said seat element, said last mentioned passage being for alternate transmission and release of fuel pressure respectively to and from said dual element; and a compression spring in said passage chamber and engaging on said dual element for, urging said dual element from said seat element, said plunger operating to control said stem valve through 'cooperation of said spring and the pressures of said fuel upon said surfaces.

4'. Liquid iuel injection mechanism comprising a housing having an injection chamber, a single discharge, passage leading from said chamber with an inwardly facing valve seat in said passage and controlling all movement of fluid out of said chamber, and a piston chamber opening into said injection chamber and approximately aligned with, and of greater cross sectional area than, said seat at said opening, a piston element slidingly fitting said piston chamber at the end opening into said injection chamber and having at one end a valve portion reduced incross section and engaging with said seat when said piston element moves toward the seat to prevent discharge of fuel from said injection chamber through said passage, a connection directly connected to said injection chamber for continuously supplying thereto, fuel under injection pressure, saidhousing having a control chamber at the end of said piston chamber opposite the end of said injection chamber, a second valve seat in said control'chamber engaged by the outer peripheral end edge of said piston element in piston element maximum diameter line to line contact therewith when that element moves away from said first valve seat, and from which its separates when said piston element moves to engage said first valve seat, a spring acting on said piston element and urging it in a direction .to engage said first valve seat, and a valve controlled duct leading to said control chamber, and opening piston element snding endwise in said space and having at one end, a valve portion reduced in cross section and extending across said injection chamber, into engagement with said seat at one end of movement of said element, said body having a valve seat in said control chamber enclosing an area, by line to line contact of piston element maximum diameter with the other end of said piston element, at least as large as the effective opening pressure area on said element in said injection chamber when said element is unseated from said outlet valve seat, a duct connected to said injection chamber for supplying thereto fuel directly and continuously under injection pressure, and means for supplying at will to said element in said control chamber, a force urging it in a direction to engage said outlet seat, including a, duct opening through the area defined by said seat in said control chamber, for supplying fluid under pressure to the adjacent end face of said piston element.

7. Liquid fuel injection mechanism comprising a housing having a longitudinal cylinder for a plunger, a fuel chamber opening into said cylinder at one end thereof and having an opening opposite said cylinder providing a valve seat, and a passage opening into said chamber for directly and continuously supplying injection fuel uhder pressure thereto; a plunger mounted in said cylinder for free sliding movement having an end, including a shoulder, adjacent said chamber, and

, a stem extendingtherefrom terminating in a valve therein through said second valve seat, whereby variation 'of the fluid pressure in said control chamber may control the injection of fluid through said discharge passage.

5. Liquid fuel injection mechanism comprising a body having a plunger space with an injection chamber at one end and a control chamber at the other end, said body having a single discharge passage from said injection chamber with an outlet valve seat facing the injection chamber, a piston element sliding endwise in said space and having at one end, a valve portion reduced in cross section and extending across said injection chamber, into engagement with said seat at one end of movement of said element, said body having a concave seat in said control chamber engaged by the periphery of the end edge of the adjacent end of said element in piston element maximum diameter line to line contact therewith at the other end of movement of said element in said space, a spring urging said element towards sai d outlet seat, a duct connected to said injection chamber for supplying thereto injection fuel directly and continuously under injection pressure, and a connection to said confor said seat, said end providing a fuel pressure surface, the opposite end of said plunger being adjacent the opposite end of said cylinder and providing a duel element serving as both a fuel pressure surface and a valve, said housing further having a seat element at said opposite end of said cylinder for said dual element and a fuel passage opening through said seat element for alternate transmission and release of fuel pressure respectively to and from said dual element, said seat element being concave and said plunger opposite end at its peripheral edge being engageable in line contact ofmaximum diameter with said concave seat element whereby substantially line contact between said elements is provided when said elements are engaged to close the fuel passage opening through said seat element: and

trol chamber through the passage defined by said concave seat for supplying against the adjacent end of said element a. fluid under a variable pressure, while injection pressure remains in said I injection chamber.

6. Liquid fuel injection mechanism comprising outlet valve seat facing the injection chamber, a.

a spring urging said dual element from said seat element, said plunger operating to control said stem valve through cooperation of said spring and the pressures of said fuel upon said surfaces.

' RALPH MILLER.

REFERENCES orrnn UNITED STATES PATENTS Number Name Date 620,829 Batchelor Mar. 7, 1899 2,274,315 Amery Feb. 24, 1942 I 681,172 Koenig Aug. 20, 1901 1,800,127 Wilson Apr. 7, 1931' 2,150,574 Amery Mar. 14, 1939 2,027,360 Alden Jan. 14, 1936 2,053,312 Amery Sept. 8, 1936 1,802,933 Von Salis Apr. 28, 1931 2,245,974 Griswold June 17, 1941 FOREIGN PATENTS Number Country Date France Feb. 28,1918

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