US3080818A

US3080818A - Fuel injection device

Info

Publication number: US3080818A
Authority: US
Inventors: Robert J Wirsching
Original assignee: Daimler Benz AG
Current assignee: Daimler Benz AG
Priority date: 1958-03-28
Filing date: 1959-03-26
Publication date: 1963-03-12
Anticipated expiration: 1980-03-12

Description

March 12, 1963 R. J. WIRSCHING 'FUEL INJECTION DEVICE 2 Sheets-Sheet 1 Filed March 26, 1959 G RN 0/ 1 mm 2 2 6 J. T m m 6 um w; I "m". &. m A nw i 1& p .Q tu M m mm m w BY M57 A TTORNE March 12, 1963 R. J. WIRSCHING 3,0 3

FUEL INJECTION DEVICE Filed March 26, 1959 2 Sheets-Sheet 2 INVENTOR. ROBERT .1 W/RSCH/NG ATTORNEY United States Patent Ofitice 3,080,818 FUEL INJECTION DEVICE Robert J. Wirsching, Korntal, near Stuttgart, Germany,

assiguor to Daimler-Benz Aktiengesellschaft, Stuttgart,

Germany Filed Mar. 26, 1659, Ser. No. 802,047 Claims priority, application Germany Mar. 28, 1958 8 Claims. (Cl. 103-2) The present invention relates to a fuel injection device, and-more particularly to a fuel injection pump, preferably for multi-cylinder diesel engines.

The present invention seeks a construction and arrangement of such a fuel injection pump which makes possible to achieve an accurate metering and distribution of the injection to the individual cylinders. Simultaneously therewith, the present invention seeks to achieve a relatively small constructional size of the injection pump and to assure safe and reliable operation thereof at all times. The present invention is characterized by a rotating cylindrically-shaped distributor which is provided along the surface thereof with an annular groove which in turn is in communication with the fuel supply lines. The cylindrically-shaped distributor is thereby provided with a number of longitudinal grooves, preferably extending in the longitudinal direction of the distributor which are brought into communication during rotation of the distributor with the connecting channels or lines for the individual nozzles. In that manner, the longitudinal grooves effectively become, for a relatively short interval of time during rotation of the distributor, fuel-supply connecting channels between the annular groove and the fuel-supply lines leading to the nozzles.

A control slide valve member having a control edge is provided, according to a further development of the main inventive concept of the fuel injection pump in accordance with the present invention, which is axially displaceable within the distributor constructed as a sleeve and which does not partake in the rotary movement thereof. Radial return-flow or discharge bores are arranged in the annular groove of the distributor which are opened by the control edge of the control slide valve member during rotation of the distributor and thereby open up or render free a path into a pressureless space to the fuel which is under pressure in the annular groove and in the longitudinal grooves. In that manner, the injection operation is terminated and the fuel quantity is accurately metered. The control takes place by the axial displacement of the control slide valve member within the sleevelike distributor. Depending on the position of the cohtrol edge, which forms the delimitation or boundary of an approximately wedge-shaped channel, the radial return flow or discharge bores of the distributor are opened sooner or later, and the fuel-supply operation is maintained operative for a relatively longer or shorter period of time. p The annular groove of the distributor is in direct communication with the cylinder of the injection pump. The longitudinal axis of the cylinder is appropriately arranged transversely to the longitudinal axis of the control member. The cylinder itself is arranged with respect to the distributor opposite the suction bore.

Additionally, according to a further feature of the present invention, the injection pump is constructed as a double-piston pump the pistons of which are driven by means of one pivot lever each from a common multi-cam disk in a respective direction toward each other. The drive shaft for the multi-cam disk may thereby simultaneously drive the distributor. For that purpose, a gear wheel each is mounted on thedistributor and on the drive shaft which are in meshing engagement with each other ..'and which have the same number of gear teeth. As a result thereof, the same rotational speed and at the same time the particular position required for the prevailing operating condition is thereby assured for the distributor as well as for the multi-cam disk. For reasons of simplification of manufacture, assembly and repair, the drive shaft is appropriately arranged parallel to the distributor.

The distributor rotates in an axial bore of a solid body or block, and the pressure lines with the pressure connecting pieces and the pressure valves thereof are arranged in bores extending radially with respect to the distributor bore.

Consequently, the pressure lines leading to the individual nozzles are in direct communication with the aforementioned longitudinal grooves of the distributor.

The actuating mechanisms for the pistons are disposed within recesses in the central region of the cylinder-shaped solid body or block. Since both pistons are disposed opposite one another within the pressure cylinder, the re-' cesses for the actuating mechanisms are also arranged opposite each other.

As already mentioned, the injection operation is controlled by axial displacement of the control slide valve member within the rotating distributor. The control slide valve member is provided at one end thereof with an internal thread into which is threadably secured an adjustable threaded bolt member which is operatively connected with a return spring and a pneumatically operated membrane member. Furthermore, a lever is operatively connected with the control slide valve member which serves as start-and-stop lever and is actuated from outside the fuel injection housing.

The drive shaft for the multi-cam disk may be provided, according to still another feature in accordance with the present invention, at the head end with an eccentric or cam member which in turn actuates the plunger of a fuel pump connected with the injection pump hous- Accordingly, it is an object of the present invention to provide a fuel injection device for internal combustion engines which is simple in construction, relatively inexpensive in manufacture and which is extremely reliable in operation.

Another object of the present invention resides in the provision of a fuel injection pump for internal combustion engines which renders possible an accurate metering of the fuel quantity injected to the individual cylinders.

Still another object of the present invention is the provision of a control system for a fuel injection pump which is relatively simple in construction yet very accurate in controlling the injection operation, particularly as to the duration thereof.

A still further object of the present invention is the provision of a drive arrangement for a fuel injection pump which assures at all times the proper positioning of all the driven parts of the injection pump in relation to the rotary position of the crankshaft of the engine.

These and other objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing, which shows, for purposes of illustration only, one embodiment in accordance with the present invention, and wherein: 7

FIGURE 1 is an axial lognitudinal cross-sectional view of the entire pump aggregate in accordance with the present invention taken along line II of FIGURE 2,

FIGURES 2 and 3 are transverse cross-sectional views through the entire pump housing taken along lines IIII and II-II of FIGURE 1,

FIGURE 4 is a partial cross-sectional view on an enlarged scale of certain details shown in FIGURE 1, and

FIGURES 5, 6 and 7 are partial cross-sectional views Patented Mar.12, 1963 taken along lines V-V, VIVI and VII-VII of FIGURE 4.

Referring now to the drawing, wherein like reference numerals are used throughout the various views to designate corresponding parts, and more particularly to FIGURES 1, 2 and 3, reference numeral 1 designates the pump housing which accommodates in the upper and larger portion thereof a cylindrieally-shaped solid body or block 2 and which is provided in the lower portion thereof with main bearings 4 and 5' for the drive shaft 3. The solid cylindrical body or block 2 is provided with an axial bore and several radial bores leading to this axial here.

The distributor 6 is rotatably arranged Within the axial bore provided in the solid body 2. The distributor 6 is constructed in a sleeve-shaped manner. The distributor 6 surrounds the control slide valve member 7 which is arranged within the distributor 6 so as to be axially displaceable. A gear wheel 8 is mounted on the end of the distributor 6 protruding beyond the cylindrically-shaped solid block 2 which gear wheel 8 is in meshing engagement with another gear Wheel 9 mounted on the drive shaft 3. The distributor 6 is provided within the central region thereof along the outside thereof with an annularly shaped groove 10' which is in communication with four radial bores 11 and two longitudinal grooves 12 (FIGURES 4-7).

The control valve member 7 axially movable within the distributor 6 extends with one end thereof beyond the distributor 6. This one end is provided with an internal thread into which an adjustable threaded bolt member 13 is threadably secured. The threaded bolt member 13 is rigidly connected with a coil spring 14- serving as return spring and with a membrane member 15. Additionally a lever 16 is operatively connected or acts on the control slide valve member 7 within the region of the internal thread thereof. The protruding end of the control slide valve member 7 is provided with an angle lever or hell crank 17 which, in cooperation with a threaded pin 18, forms an abutment.

A wedge-shaped channel or groove 19 (FIGURES 1 and 4) is machined into the other end of the control slide valve member 7 which includes an inclined control edge 20 (FIGURESI and 4). The wedge-shaped channel 19 and the inclined control edge 29 are disposed within the region of the annular groove 16 of the distributor 6.

The radial bores provided in the solid cylindricallyshaped block 2 are constructed so as to have diameters decreasing in a steplike manner toward the center of this block. Pressureconnecting-pieces 21 (FIGURE 3) for the individual fuel injection nozzles are threadably secured in the radial bores. The pressure valves of any suitable known construction are arranged within the pressure-connecting pieces 21. Pressure channels 22 are in communication or adjoin the pressure-connecting pieces 21 in the direction toward the distributor 6. The suction connecting piece 23 (FIGURE 2) provided with a suction valve of any suitable construction is arranged in a further radial bore of solid block 2. The suction connecting piece 23 is directly in communication over a channel 24 with the annular groove 10 of the distributor 6.

The pump channel 25 (FIGURES 1 and 6) is disposed opposite the suction channel 24 in relation to the distributor 6 which pump channel 25 establishes the connection or communication between the pump cylinder 26 and the annular groove 10. Two oppositely disposed pump pistons 27 and 28 (FIGURE 2') operate within pump cylinder 26 in mutually opposite directions. The two

pistons

27 and 28 are actuated by two pivot levers 31 and 32 (FIGURE 2) against the force of

coil springs

29 and 30. The two

coil springs

29 and 30 are disposed intwo oppositely disposed bores or recesses of the solid cylindrically-shaped body 2.

A multi-cam disk 33, which is provided with four

individual cam portions

34, 35, 36 and 37 (FIGURE 2), is mounted on the drive shaft 3 between the

main bearings

4 and 5. The multi-cam disk 33 is in operative connection with the pivot levers 31 and 32 over appropriate roller members of suitable conventional construction. By reason of the symmetric arrangement of the pivot levers 31 and 32, the support and bearing of the cam-and-drive shaft 3 is almost completely relieved of any loads or stresses. The drive shaft 3 extends with one end thereof beyond the pump housing 1. At the place where the drive shaft 3 protrudes beyond the pump housing 1,,the latter is provided with a flange 38 (FIG- URE l) which is sealed with respect to the drive shaft 3 by means of an appropriate seal 39. The other end 49 of the drive shaft may be used for purposes of driving the supply pump which is not illustrated in detail in the drawing and which may be of any suitable construction.

FIGURES 4 to 7 show in greater detail the area of the distributor 6 and of the control slide valve member 7 as well as of the solid block 2 Within the region of the annular groove 10. Two cross-sectional views through the pressure bores 22 and 22 as well as 22 and 22 are shown in FIGURES 5 and 7, respectively, while FIGURE 6 shows a cross-sectional view through the suction bore.

Operation The operation of the fuel injection pump and control arrangement in accordance with the present invention is as follows:

The energy necessary for the operation of the pump is supplied from any other suitable device or prime mover, for example, from the starter or the engine, either directly or indirectly to thereby impart the necessary rotary movement to drive shaft 3. The rotating shaft 3 drives the distributor 6 over gear wheels 9 and 8. Simultaneously therewith, the multi-cam disk 33 rotates which thereby moves or actuates the pivot levers 31 and 32 sequentially four times per revolution and therewith effectuates four piston strokes of the

pistons

27 and 28 per revolution of drive shaft 3. As a result of the movements of the

pistons

27 and 28, fuel is drawn in over suction connection piece 23 and suction channel 24 which fuel is supplied over the annular groove 10 and a longitudinal groove 12 into a pressure channel, for example, the pressure channel 22 of FIGURES 4 and 5. Since the drive shaft 3 and the control distributor 6 are in direct operative engagement with each other over gear wheels 8 and 9, both of these parts rotate in synchronism, i.e., for each pressure stroke one of the pressure channels 22; through 22 is connected with the pressure space 26 of the pump. The drive shaft 3 and the distributor 6 have to rotate in unison with the crankshaft in order that the injection takes place each time in the desired position of the engine pistons.

For purposes of metering the injection quantity, the n ection operation is terminated sooner or later in the in ection device according to the present invention. The termination of the injection operation takes place by openmg the annular groove 10 which contains the fuel under pressure. The termination and duration of the interruption of the injection operation is dependent on the respective axial position of the control slide valve member 7. The annular groove 10 is provided at the bottom thereof with four radial return flow or discharge bores 11 (FIGURES l and 6) which are sequentially swept or passed over by the wedge-shaped channel 19 provided in control slide valve member 7. As soon as the control edge 20 of the wedge-shaped channel 19 renders free or opens up a discharge bore 11, the fuel under pressure flows over the discharge bore 11 and the wedge-shaped channel 19 into a pressureless space within the pump housing. The injection operation is therewith terminated and interrupted for such period of time as the wedgeshaped channel 19 renders free the respective discharge bore 11. The duration of the release of the respective discharge bore 11 or, in other words, the period of time of termination of the injection operation is, therefore, dependent on the axial position of the inclined control edge 20, i.e., on the width of the elfective wedge-shaped channel 19. The width of the wedge-shaped channel 19 increases toward the right end of the control valve member 7 as seen in FIGURES 1 and 4. With an axial displacement of the control slide valve member 7, the period of time of termination of the injection operation may thereby be varied and the fuel injection quantity may thereby be accurately metered.

For purposes of axial displacement of the control slide valve member 7, the latter is connected with a membrane member 15 and a return spring 14. The membrane member 15 is pneumatically actuated depending on the vacuum prevailing in the inlet manifold of the engine (not shown). For purposes of adjusting to full load position, an angle lever or bell-crank 17 (FIGURE 1) is additionally pivotally connected as abutment .at the control slide valve member 7.

While I have shown and described only one embodiment in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of many changes and modifications within the spirit and scope of the present invention, and I, therefore, do not wish to be limited to the details described and illustrated herein but intend to cover all such changes and modifications thereof as are encompassed by the scope of the appended claims.

I claim:

1. A distributor arrangement for a fuel injection pump having a casing, especially for multi-cylinder engines, comprising rotating cylindrically-shaped distributor means provided with an annular groove along the outer surface thereof, fuel input line means including a suction line in communication with said annular groove and check valve means in said suction line, at least one injection nozzle, a connecting channel for each individual injection nozzle, means forming fuel-carrying channels including a number of grooves extending longitudinally of said cylindrically-shaped distributor means on the outer surface thereof, said grooves extending in the longitudinal direction of said distributor means for sequentially bringing into communication said annular groove with the individual connecting channels during the rotation of said distributor means, said distributor means being of sleeve-like construction, a control member provided with control edge means and non-rotatably supported within said sleeve-like distributor means, said annular groove being provided with radial discharge bores in communication with said first-mentioned fuel-carrying grooves, low pressure space in said fuel injection pump casing, said control edge means effectively and sequentially opening said discharge bores by establishing a communication between respective discharge bores and said low pressure space during rotation of said distributor means, and pump means adjacent to and in communication with said annular groove including a piston-cylinder assembly for drawing in fuel through said fuel input line means and said annular groove and for placing the fuel therein under pressure whereby said fuel passes from said assembly back through said annular groove and into said connecting channels through the longitudinal grooves, and drive means for said pump means and said distributor means.

2. A fuel injection pump, especially for multi-cylinder diesel engines, comprising a solid block provided with an axial bore, cylindrically-shaped distributor means rotatably supported within said axial bore and provided with an annular groove along the outer surface thereof, fuel input line means including a suction bore in communication with said annular groove and check valve means for said suction bore, a plurality of injection nozzles, a connecting channel for each individual injection nozzle effectively forming a pressure line to conduct therethrough fuel under pressure to the individual nozzles, and means including at least one groove extending essentially in the longitudinal direction of said distributor means on the outer surface thereof for bringing said annular groove into communication with the individual connecting channels during the rotation of said distributor means, pump means in communication with said annular groove including a cylinder having the longitudinal axis thereof extending essentially transversely to the longitudinal axis of said distributor means, and piston means in said cyll inder for drawing in fuel through said fuel input line means and said annular groove and for placing the fuel under pressure whereby said fuel passes from said cylinder, back through said annular groove and into said connecting channels through said longitudinal groove, said cylinder being disposed opposite to said suction bore in relation to said distributor in proximity to said annular groove and in direct communication therewith, and drive means for said pump means and for said distributor means. I

3. A fuel injection pump according to claim 2, wherein said piston means for said pump means includes two pistons disposed in said cylinder, and wherein said drive means includes a drive shaft and a common multi-cam disk attached .to said drive shaft, and lever means for driving said pistons in opposite directions with respect to each other from said multi-cam disk.

4. A fuel injection pump, especially for multi-cylinder engines, comprising rotating cylindrically-shaped distributor means provided with an annular groove along the outer surface thereof, fuel input line means including a suction line in communication with said annular groove and check valve means in said suction line, a plurality of injection nozzles, a connecting channel for each individual injection nozzle, means including a number of grooves on the outer surface of said distributor means for bringing into communication said annular groove with the individual connecting channels during the rotation of said distributor means, and control valve means including a radially extending discharge groove in said distributor means and a. non-rotatable control slide valve member disposed within said last-mentioned groove for efiectively metering the quantity of fuel injected by each nozzle by varying the length of the injection period by said control valve means, pump means adjacent to and in communication with said annular groove including a piston-cylinder assembly for drawing in fuel through said fuel input line means and said annular groove and for placing the fuel therein under pressure whereby said fuel passes fromsaid cylinder, back through said annular groove and into said connecting channels through said number of grooves, and

drive means for said pump means and for said distributor means.

5. A fuel injection pump according to claim 4, wherein said control slide valve member is a non-rotatable pinlike member extending within the distributor means, said pin-like control member being provided at one end thereof with an internal thread, an adjusting bolt member threadably secured within said internal thread, means including a return spring and a membrane member operatively connected with said bolt member to adjustably move said pin-like control member in dependence on the pressure in the inlet manifold.

6. A fuel injection pump, especially for multi-cylinder diesel engines comprising a solid block provided with an axial bore, a cylindrically-shaped distributor rotatably supported within said axial bore and provided with an annular groove along the outer surface thereof, with radial discharge bores in communication with said annular groove, and with a plurality of grooves in communication with said annular groove and extending in the longitudinal direction of said distributor or the outer surface thereof, a first radial bore in said block accommodating therein fuel input means including a suction line in direct communication with said annular groove and suction valve means, a plurality of injection nozzles, additional radial bores in said block, each of said additional bores accommodating therein a connecting piece provided with pressure valve means and a fuel supply line leading to a corresponding injecting nozzle, said additional radial bores and said longitudinal grooves being so arranged relative to each other that the former are brought sequentially into communication with the latter during rotation of said distributor, pump means in direct communication with said annular groove including means for drawing in fuel through said first radial bore and placing the fuel under pressure in said longitudinal grooves, drive means common to both said pump means and said distributor, a nonrotatable control member within said distributor, said control member being provided with a wedge-shaped channel effectively sweeping past said discharge bores during rotation of said distributor, and control means axially displacing said control member to thereby vary the fuel quantity injected.

7. A fuel injection pump according to claim 6, wherein said pump means includes two pistons, two recesses in said block for accommodating therein said pistons, cam means on said drive means and two levers operatively connecting said cam means with said pistons to actuate the same in mutually opposite directions.

8. A fuel injection pump according to claim 7, wherein said drive means includes a drive shaft, one gear wheel on said drive shaft, another gear wheel on said distri'outor in meshing engagement with said first-mentioned gear wheel, and both of said gear wheels having the same number of teeth.

10 References Cited in the file of this patent UNITED STATES PATENTS 2,210,067 Cummins Aug. 6, 1940 2,243,861 Hautzenroeder June 3, 1941 2,385,089 Lerner Sept. 18, 1945 15 2,599,522 Coe June 3, 1952 2,667,840- High Feb. 2, 1954 2,674,236 Humber Apr. 6, 1954 2,759,422 Miller Aug. 21, 1956 2,827,852 Links Mar. 25, 1958 20 2,883,934 Roosa Apr. 28, 1959 FOREIGN PATENTS 680,145 Great Britain Oct. 1, 1952 933,182 Germany Sept. 22, 1955

Claims

1. A DISTRIBUTOR ARRANGEMENT FOR A FUEL INJECTION PUMP HAVING A CASING, ESPECIALLY FOR MULTI-CYLINDER ENGINES, COMPRISING ROTATING CYLINDRICALLY-SHAPED DISTRIBUTOR MEANS PROVIDED WITH AN ANNULAR GROOVE ALONG THE OUTER SURFACE THEREOF, FUEL INPUT LINE MEANS INCLUDING A SUCTION LINE IN COMMUNICATION WITH SAID ANNULAR GROOVE AND CHECK VALVE MEANS IN SAID SUCTION LINE, AT LEAST ONE INJECTION NOZZLE, A CONNECTING CHANNEL FOR EACH INDIVIDUAL INJECTION NOZZLE, MEANS FORMING FUEL-CARRYING CHANNELS INCLUDING A NUMBER OF GROOVES EXTENDING LONGITUDINALLY OF SAID CYLINDRICALLY-SHAPED DISTRIBUTOR MEANS ON THE OUTER SURFACE THEREOF, SAID GROOVES EXTENDING IN THE LONGITUDINAL DIRECTION OF SAID DISTRIBUTOR MEANS FOR SEQUENTIALLY BRINGING INTO COMMUNICATION SAID ANNULAR GROOVE WITH THE INDIVIDUAL CONNECTING CHANNELS DURING THE ROTATION OF SAID DISTRIBUTOR MEANS, SAID DISTRIBUTOR MEANS BEING OF SLEEVE-LIKE CONSTRUCTION, A CONTROL MEMBER PROVIDED WITH CONTROL EDGE MEANS AND NON-ROTATABLY SUPPORTED WITHIN SAID SLEEVE-LIKE DISTRIBUTOR MEANS, SAID ANNULAR GROOVE BEING PROVIDED WITH RADIAL DISCHARGE BORES IN COMMUNICATION WITH SAID FIRST-MENTIONED FUEL-CARRYING GROOVES, LOW PRESSURE SPACE IN SAID FUEL INJECTION PUMP CASING, SAID CONTROL EDGE MEANS EFFECTIVELY AND SEQUENTIALLY OPENING SAID DISCHARGE BORES BY ESTABLISHING A COMMUNICATION BETWEEN RESPECTIVE DISCHARGE BORES AND SAID LOW PRESSURE SPACE DURING ROTATION OF SAID DISTRIBUTOR MEANS, AND PUMP MEANS ADJACENT TO AND IN COMMUNICATION WITH SAID ANNULAR GROOVES INCLUDING A PISTON-CYLINDER ASSEMBLY FOR DRAWING IN FUEL THROUGH SAID FUEL INPUT LINE MEANS AND SAID ANNULAR GROOVE AND FOR PLACING THE FUEL THEREIN UNDER PRESSURE WHEREBY SAID FUEL PASSES FROM SAID ASSEMBLY BACK THROUGH SAID ANNULAR GROOVE AND INTO SAID CONNECTING CHANNELS THROUGH THE LONGITUDINAL GROOVES, AND DRIVE MEANS FOR SAID PUMP MEANS AND SAID DISTRIBUTOR MEANS.