US2073604A

US2073604A - Fuel distributing valve

Info

Publication number: US2073604A
Application number: US1490A
Authority: US
Inventors: Beeh Louis
Original assignee: American Bosch Arma Corp
Current assignee: Ambac International Corp
Priority date: 1935-01-12
Filing date: 1935-01-12
Publication date: 1937-03-16
Anticipated expiration: 1954-03-16

Description

L. BEH

FUEL DISTRIBUTING VALVE FiledJan. 12. 1935 A III. lla

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Patented Mar. 16, 1937 UNITED STATES PATENT OFFICE FUEL DISTRIBUTING VALVE Application January 12, 1935, serial No. 1,490

3 Claims.

This invention relates to a fuel supply system and more particularly to a fuel supply system for internal combustion engines of the injection type.

In internal combustion engines of this type 5 it has heretofore been proposed to provide a fuel supply chamber common to al1 cylinders of the engine, which supply chamber is maintained under high pressure and placed' in communication with the engine cylinders in proper sequence by means of distributing valves driven in synchronism with the engine.

In such constructions the fuel supply chamber must be a very strong construction to withstand the high pressures, 4000 pounds' or more per square inch necessary to provide the desired atomization of the fuel.

Heretofore in some constructions such supply chambers have been formed as a part of the housing of the distributing mechanism. Such construction is desirable in that a unitary structure is provided which is easy of assembly, but such structures are necessarily heavy since all parts are made of material capable of withstanding the high pressure to which vthe supply chamberis subjected.

It is one of the objects of .this invention to provide alight construction in which the distributing mechanism is provided -in a unitary structure.

with the supply chamber, but which structure is of great strength at all points subject to the high pressure of the fuel.

To this endI provide a hollow member of bronze or steel to form the supply chamber and cast the housing for the remaining elements of the system about this member, the casting being of light material, such as aluminum.

A further difficulty experienced with devices of this` nature resides in the fact`that due to the maintained pressure of the supply chamber it is diicult to reduce pressure at the fuel nozzle 'suiciently rapidly to prevent drip. In injection engines of the type in which fuel is supplied to the engine by a separate pump for each cylinder itis possible to completely reduce the pressure in the fuel line at or about the end of the pumpsstroke by opening a relief valve. readily available to the present type of injection system, due to the fact that the fuelis continuously under high pressure in the main supply chamber. To provide such systems with some means to prevent drip, it has heretofore been proposed to provide a mechanically actuated piston which withdraws fuel from the supply line after the distributor valve is closed. Such a construction involves additional gearing lfor the Such a system is not drive of the drip prevention plunger. It is one of the objects of this invention to provide a structure in which this function is performed by the movement of the distributor valve itself.

It is a further object of this invention to lpro- `5 vide a structure in which the pressure of the fuel acts as a return spring for all reciprocating parts, thereby avoiding numerous difculties arising in practice in connection with the use of springs in such structures. 10

Other objectsfwill in part be obvious and in part be pointed out hereinafter.

To the attainment of the aforesaidobjects and ends, the invention still further resides in the novel details of construction, combination and l5 arrangement of parts, all of which will be first fully described in the following detailed description, then be particularly pointed out in the appended claims, reference being had to the accom panying drawing, inwhich: i 20 Fig'. ,l shows a transverse section with parts in side elevation through the housing of one form t of distributor Vconstructed in accordance with my invention; Fig. 2 is a diagram showing the complete fuel supply circuit; Fig. 3 shows a longitudi- 25 nal section, with parts in side elevation, of the preferred form of the fuel injector.

Referring to Fig. 1, reference numeral I0 indicates a housingwhich is preferably a casting of light alloys, such as aluminum. In this hous- 30 ing is cast a high pressure metal insert I2 which may be made out of bronze o-r steel alloys. It

'will be understood that in the manufacture of the device, either the insert I2 may be formed rst and the housing I0 cast thereabout, or where 35 desired the housing. I0 may be first cast and the insert I2 subsequently cast .in the .preformed housing. In either case a unitary, integral str ucture is formed. The object of this feature is to create an apparatus light in'weight and strong 40 in pressureresistin'g qualities.

The insert I2 is hollow, defining a high pressure supply chamber I3 in which fuel is maintained under high pressure in a manner which will be hereinafter described. Mounted into the insert 45 I2 is a valve housing I4 containing the valveA I6 andy the valve,seating plunger I8. Adjacent to this valve housing I4 is mounted the housing 20 of the valve actuating plunger 22. Both the valve housing III 'andthe plunger housing 20 are held 50 in position in the housing I0 by a nut 24. The plunger 22 is operated through a lever 26 by the cam 2li.I The lever 26 is adjustably pivoted on an eccentricr shaft 30. y

In the operation of the form shown in this 55 figure, fuel is compressed by any well known means, such as plunger or gear pumps, into the high pressure supply chamber I3. Upon actuation of lever 26 by cam 28, the plunger 22 and 5 valve I6 are lifted until the lower edge of the valve I6 uncovers one'end of a passage I5 in the valve housing I 4. This permits fuel to ow from chamber I3 through passage I5 to a chamber 2| formed in housing or liner 20 above plunger 22, and thence 10 by way of a passage 23 leading to the fuel injection nozzle. It will be understood that the nozzle I terminated by the downward movement of the valve I6 closing the passage I5 and it will be observed that after this closure the valve I6 moves downwardly for some distance before it comes to 25 rest on seat I1. This permits retraction of the plunger 22 for some distance after the fuel supply from chamber I3 has been cut off, thus reducing pressure in chamber 2| and consequently withdrawing fuel from passage 23 and the connecting 30 passages leading to the fuel nozzle, causing a quick closure thereof and preventing drip there-y from.

It will be observed that no springs are utilized for the closing movement of valve I6, this motion 35 being effected by pressure of the fuel in chamber' I3 acting upon the valve seating plunger I8 which is reciprocative in valve housing I4, and which rests upon the upper end of valve I6. A passage 32 is provided in the valve housing I4 connecting 40 the space below the plunger I8 with a fuel tank under atmospheric pressure so that the pressure in chamber I3 is not resisted by pressure of fuel leaking around plunger I 8 to the lower side there- .of. It readily will be seen that this construction 45 eliminates the necessityfor springs, thereby entirely avoiding the difllculty of adjusting these elements for wear and also avoiding trouble arising from crystallization of the metal forming the spring which arises in practice'due to the con- 50 tinued flexing thereof. f

The disposition of parts in the complete supply system will best'be understood by reference to the diagrammatic disclosure of. the same in Fig. 2. Referring to this figure,'reference numeral 10 55 indicates the main supply tank which may be at atmbspheric pressure and from which fuel is drawn by a high pressure pump, one of the cylinders ofl which,is indicated at 12. Fuel'is forced V by the pump 12 through pipe' 13 to the high pres-v 60 sure chamber 43. From thence it passes by way of passages 44 to the distributor valves 46 and thence by way of passages 14 to the nozzles 19 which are mounted in the usual manner on the engine. The chamber 43u is also in communica- 65 tion by way of reduction valve 64 with a4 low pressure chamber 62 in such a manner that when the pressure in chamber 43 is maintained at about 4000 pounds per square -inch, the pressure in the low pressure,A chamber will preferably be about 70 `1000 pounds per square inch. Pressure inl excess 1 oi this is `relieved by valve 66 which conducts the excess fuelby way of pipe J8 to the supply tank 10. The low pressure chamber 62 communicates by way of pipe 16 having branches 11 with the 7 5 outerend of each of the injection valves 18.

'I'he injection valve, details of which may be seen in Fig. 3, consists of a housing 80 and a nozzle member 8| connected therewith by means of a nut 82. A valve 83 is seated in the nozzle member 8| and provided with a stem 84 extending through the housing 80. A diaphragmv 85 closes the outer end of the housing 80 and is held in position by a nipple 86 which is adapted to be connected to pressure branch 11 of pressure line 16 connected with the low pressure chamber 62.y

' Upon closure of the valves 46 the supply of fuel to the nozzle member ceases and immediately thereafter isl withdrawn by further downward movement of the valve member in the manner previously described. The constant pressure in chamber 81 now acts as a spring to force the valve 83 tightly upon its seat.

It will be understood that in practice the injec- Y tion valves may be mounted on the cylinders of the engine to inject the fuel directly thereinto or they may be mounted to inject fuel into the air intake manifold. In the appended words "injection engine are intended to include all types of engines having an injector to which fuel is supplied under pressure.

In connection with engines of either type the advantages described above are desirable though it will be obvious that the feature of preventing drip is especially useful in connection with the engines of the direct injection type.

It will thus be seen that my invention provides a fuel supply system which is free from springs throughout. It will likewise be seen that drip is effectively prevented in a fuel supply systeml of the common rail type; that a drop in the fuel supply pressure during the injection period ls Yautomatically prevented by the opening movement ofthe control valve itself or of parts connected therewith; and that a light, strong, compact and easily assembled structure is provided.

valve, said valve'including a cylindrical member reciprocative in a bore having a lateral passage f adapted to communicate with a source of fluid under pressure, said bore having a reduced portion spaced from said 4lateral passage and providing a stop forI said cylindrical member; actuating means for said valve including, a plunger;

' a second bore of larger diameter than said cylin drical member in which said plunger reciprocates;

a discharge passage leading from said second bore; and a stem connecting said plunger and said cylindrical member of lesser diameter than they reduced portion of said bore, whereby when said valve is in open positionfluid flows from said source through said lateral passage, said first mentioned bore, said reduced portion, said second bore and thence to said discharge passage, and

'1.,In a fuel injection engine: a fuel distributing aoraeoa whereby upon closure of said lateral passage further movement of said plunger reduces the pressure in said discharge passage.

2. In a fuel injection engine, a fuel distributing device including a pair of cylindrical members of different diameters, cylinder b ores in which said members reciprocate, a passage adapted to communicate with a source of uid under pressure, said passage opening into the smaller of said bores at a point which is normally closed by one of said members, a discharge passage leading from the space of the other of said bores beyond the innermost point of travel of the member therein, and means eiective during an intermediate portion of one stroke of said members for establishing communication between said rst mentioned passage and said space, said difference in diameters of said cylindricalmembers causing a reduction of pressure in said space on the reverse stroke thereof.

3. In a fuel injection engine, a distributing valve, said valve including a cylindrical member, a bushing having .a bore in which said member reciprocates, a passage adapted to communicate with a source of fluid under pressure opening into said bore and positioned to be opened during an intermediate portion of the stroke of said valve, a second cylindrical member of larger diameter than said first cylindrical member, a second bushing providing a second bore in which said second cylindrical member reciprocates, means for actuating said members, means providing communi cation between said passage and said second bore after a predetermined movement of said valve in one direction, and a discharge passage communicating with said second bore at a point beyond the innermost position of said second cylindrical member.

LOUIS BEEH. 4 ein