GB1576236A - Distributor assembly for use with a fuel pump - Google Patents

Description

(54) A DISTRIBUTOR ASSEMBLY FOR USE WITH A FUEL PUMP (71) I, BENJAMIN BIRENBAUM, a Canadian citizen residing at 505 Keele Street, Toronto, Ontario, Canada, do hereby declare the invention, for which I pray that a patent may be granted to me and the method by which it is to be performed, to be particularly described in and by the following statement: The specification described a fuel injection pump inwhich a distributor assembly is used with a pump unit for the distribution of equal fuel quantities to the cylinders of a multi-cylinder internal combustion engine.

The pump unit operates such that the number of deliveries of fuel metered by the pump equal the number of firing strokes in the associated engine with the distributor assembly connecting each of the cylinders within the engine in turn to the pump unit by means of delivery channels. Only one cylinder is in communication via the distributor with the pump unit at any one time.

Background of the Invention There are presently two general types of fuel injection pumps including the common in-line type and the distributor type. The effectiveness of both types is limited due to the fact that the degree of pressure and the amount of fuel delivered to each cylinder changes over time which results in an unequal supply of fuel and an untuned engine. Some of the cylinders burn too lean and the others burn too rich, so there is excess fuel consumption, a loss of engine power and smoking at lower R.P.M. The unequal distribution occurs as a result of wear which increases the more the pump is used.

It is therefore a prime object of the present invention to provide a distributor assembly for a fuel injection pump which assembly is highly durable and which supplies equal quantities of fuel charges to each cylinder of an internal combustion engine.

It is another object of the present invention to provide a distributor assembly in which the metered amount of fuel delivered to each cylinder is consistent from cylinder to cylinder throughout the working or life span of the fuel injection pump.

Brief Summary of the Invention The above objects are achieved according to this invention by providing a distributor assembly including a plurality of plunger type valves used for the sole purpose of distributing fuel from a pump unit to the cylinders of a multi-cylinder internal combustion engine. The purpose of the pump is to pump and meter fuel to the distributor assembly. The pump unit itself is not involved in the distribution of fuel.

Each of the cylinders in the multi-cylinder engine is provided with a delivery duct and that delivery duct is connected to the pump unit by the distributor assembly. Only one delivery duct is in communication with the pump unit at any one time, so that the delivery ducts of the various cylinders are connected to the pump unit in sequence.

Each of the distributor plunger type valves is operated by means of a flat-faced distributor cam lobe. As a result of the construction of the cam lobe, the distributor plunger valves are held in a stationary position while connecting the delivery ducts to the pump unit throughout the entire delivery stroke of the plunger of the pump unit. Due to the stationary position of the distributor plunger valves throughout the delivery stroke of the pump plunger the wear on the individual distributor plungers, bores and fuel ports is less than the wear on distributor assemblies in which the distributor valves are constantly moving. In the present arragement, the quantity of fuel distributed to each cylinder is consistent from cylinder to cylinder over time as the unit operates.

Brief Description of the Drawings The aforementioned and other objects, advantages and features of the present invention will become apparent in the following detailed description of the preferred embodiments according to this invention, having reference to the accompanying drawings in which: Figure 1 is a cross-sectional view of a fuel injection pump head incorporating a distributor assembly according to this invention.

Figure 2 is a representative section of the fuel injection pump head of Figure 1 taken along the lines 2-2.

Figure 3 is a representative sectional view of the fuel injection pump head of Figure 1 taken along the lines 3-3.

Figure 4 is a front elevational view of the fuel injection pump head of Figure 1 mounted on a pump housing.

Figure 5 is a front elevational view of a cam mechanism for operating the distributor valve plungers according to this invention.

Figure 6 is an isometric cross-sectional view of pump unit for pumping and metering fuel to the distributor assembly according to this invention.

Figure 7 is a front cross-sectional view of the pump unit of Figure 6 when adjusted to meter a different quantity of fuel.

Figure 8 is a side elevational view representative of the bottom portions of the pump unit shown in Figures 6and 7.

Figure 10 is a sectional view of one of the distributor valves shown in Figure 1.

Figure 11 is a part sectional elevational view of another embodiment of a fuel injection pump head showing an alternative method of delivering fuel from the distributor assembly to the cylinders of an engine.

Detailed Description of the Preferred Embo diments According to this Invention Referring primarily to Figure 1, a fuel injection pump comprises a hydraulic pump head generally indicated at P including a pump head casing 1 and a pump unit having a pump plunger 5 reciprocable within a cylinder bore formed by bushing 6, as best shown in Figure 6. Located below the pump plunger is a camshaft following roller3 rotatably mounted in its camshaft follower 2.

The fuel injection pump head is mounted in a pump housing as shown in Figure 4. The pump housing, which does not constitute part of the present invention includes a cam shaft 39 provided with a cam lobe 40. The cam shaft is driven by an engine (not shown) and the cam lobe reciprocates pump plunger 5 within its cylinder bore through roller 3 and follower 2. The pump unit meters and pumps fuel to the distributor assembly arranged around it.

Provided in the pump housing is a shaft 43 provided with a pinion gear 44. Shaft 43 and gear 44 are driven from the shaft 39 by means of a reduction gear assembly generally indicated at G. Pinion gear 44 meshes with a ring gear 25 of a distributor cam 23 mounted at the base of the fuel injection pump head. Cam 23 is provided with a flat-faced distributor cam lobe 24. Distributor cam 23 rotates about bearings 26.

Arranged around pump plunger 5 are a plurality of distributor valves including valve plungers 16 mounted in their respective cylinders formed by means of bushings 15. Each of the distributor valve plungers 16 is provided at its lower end with a distributor cam follower 28 and a distributor follower roller 29, rotatably mounted therein. The distributor valve plungers are reciprocated within their respective cylinders in succession by cam lobe24 of distributor cam 23 through rollers 29 and follower 28.

Fuel is supplied by means of a low pressure supply pump (not shown) to fuel reservoir 12 through fuel supply duct 11, as shown in Figure 3. Duct 11 extends from inlet 11a to reservoir 12 and back to outlet port 11b to a pressure equalizer check valve 13, which is mounted at the outlet port for equalizing pressure in the system so as to provide fuel circulation with a fuel tank (not shown) for pump cooling and air venting.

The fuel (under low pressure) which is in the pump fuel reservoir 12 enters the pump cylinder chamber through inlet drillings 7 while the pump plunger 5 is held in its lowest position by means of plunger pressure spring 4. As cam shaft 39 is rotated, lobe 40 lifts pump plunger 5 through roller 3 and follower 2 upwardly through a delivery stroke to its uppermost position, as shown in Figure 1. The fuel, which is under pressure throughout the delivery stroke, lifts pump check valve 51 up off its seat in pump check valve body 50, against the pressure of spring 52. As the fuel passes from the pump cylinder it enters a plurality of delivery ducts 14 which are drillings in the pump casing extending from the check valve through the pump casing to the distributor valves. The number of delivery ducts equals the number of cylinders in the engine.

Pump plunger 5 includes two opposing helical slots 8 (only one of which can be seen in the drawings). Slots 8 are machined in the upper part of the pump plunger in the area of inlet drillings 7. The purpose of the slots is to meter fuel as follows. The relation of the helical slots with respect to the inlet drillings 7 changes with partial rotation of pump plunger 5, thereby determining the effect part of the delivery stroke of the pump plunger. In Figure 6, the effective length of the delivery stroke is indicated by the length of arrow A. In Figure 7, the effective length of the delivery stroke is indicated by arrow B. In Figure 7 the delivery part of the stroke is completed before the pump plunger reaches its top position because the inlet drillings are unveiled by the two helical slots.The fuel, which is delivered into the pump chamber but which is not pumped by the pump, flows back to fuel supply reservoir 12.

Pump plunger 5 is rotated partially through the axial movement of control rack 10 provided with gear teeth 10a which mesh with gear teeth 9a of a control sleeve 9, as shown in Figure 2. Pump plunger 5 includes at its lower end a pair of radial extensions 62 which are engaged in slots of the control sleeve formed by downward extensions 61, as shown in Figure 8. Therefore, the pump plunger rotates with the control sleeve.

Also provided in the pump head is a pump bushing adjusting sleeve having two toothlike projections 56 at its lower end which extend into slots 56a provided at the upper end of bushing 6. Adjusting sleeve 55 includes at its upper end a flange provided with extended slots 63 through which extend securing bolts 57. Threaded into sleeve 55 is a check valve retainer 53 housing the check valve spring and having a vent drilling 54 sealed by sealing cap 58 having a vent screw 59.

Due to the provision of the extended slots, sleeve 55 can be partially rotated to provide the initial setting for the metering of fuel. If proper adjustment cannot be achieved through the use of control rack 10, then further metering can be accomplished through the adjustment of sleeve 55. Therefore when metering through the use of the rack, control sleeve 9 and plunger 5 are rotated with respect to bushing 6. When metering through the use of the adjustment sleeve, bushing 6 is rotated relative to the control sleeve and pump plunger.

Referring to Figure 10, each distributor valve includes drilling 18 which passes through bushing 15 to form a continuation of one of the delivery ducts 14. Located at the upper end of drilling 18 is an annular channel 31, only half of which appears in Figure 10. Located above bushing 15 is a delivery valve body 20 having an annular channel 32 at its lower end in communication with channel 31. Extending upwardly from channel 32 are drillings 33 leading to the interior of the delivery body. Bushing 15 and delivery valve body 20 are retained by fitting 22.

Each of the distributor valve plungers includes an annular groove 17. When the individual distributor valve plungers are in a distributing position, groove 17 is aligned with drilling 18. Annular channels 31 and 32 as well as drillings 33 form a continuation of the delivery duct and drilling. The valve plungers also include drillings 34 for the purpose of breathing during operation of the distributor. An annular groove and outlet drilling 35 is provided in bushing 15 for collecting any possible seeping fuel, some of which lubricates the valve plunger.

Drilling 35 is connected with drilling 36 extending through the pump casing and leading to the pump fuel reservoir 12.

Each of the distributor valves operates in the following manner: As distributor cam 23 is rotated, the flat-faced distributor cam lobe 24 lifts each of the cam follower rollers and its follower 28 of the distrbutor valves in succession, thereby lifting each of the distributor valve plungers in sequence within their bushings. While one of the distributor valve plungers is in an upper open position held by cam lobe 24, the remaining distributor valve plungers are held, by pressure springs 30, in their lowermost closed positions on cam 23 through their followers and follower rollers, as indicated by the distributor valve plunger shown in the left-hand portion of the Figure 1. The distributor valve plunger in the right-hand portion of Figure 1 is in its uppermost open position.

As is to be understood from the drawings and due to the close fit between each of the valve plungers and its respective bushing, drillings or delivery passages 18 are cut off from delivery ducts 14 when the distrbutor valve plungers are in their lowermost position. However, when a distributor valve plunger is lifted by means of cam lobe 24 of cam 23, the distributor valve plunger annular groove 17 is in alignment with drilling 18, thereby making a continuous path around the valve plunger body so that fuel flows from the pump unit through duct 14 and drilling 18 via annular groove 17. As earlier mentioned, although all the ducts are full of fuel under pressure, fuel cannot pass around more than one distributor valve body plunger at any one time because distributor cam 23 is only provided with one cam lobe.

The reason for the flat upper face of the cam lobe is to provide a distributing system in which the successively operated distributor valve plungers remain stationary when in the distributing position. The length of cam lobe 24 is such that the plungers are held in the distributing position throughout the entire delivery stroke of the pump plunger.

In conventional systems, the fuel under pressure acts as an abrasive against the ports of the fuel passage as the components move during the distribution of fuel. In the present system there is no abrasion because the distributor valve plungers are stationary during distribution. Therefore, referring to Figure 1, the delivery valve plunger shown on the right hand portion of the drawing is maintained in a position where annular groove 17 is in alignment with drilling 18 through the entire upstroke of plunger 5.

Returning to Figure 4, the pump housing, which may contain a governor (not shown) includes a control lever shaft 48. A pump control lever 49, which may be operated manually is connected with positioning rack 10 through intermediate linkage 46 and intermediate lever 47 mounted on the control lever shaft. The fuel output of the fuel pump is determined by the positioning of the pump control lever 49, which may be positioned to provide for a maximum or minimum R.P.M. position. The pump control lever is held in idle position by idle stop piston screw 45, which may be pressed inwardly to permit the control rack to be moved to a stop or neutral position in which no fuel is delivered.

In summarizing the operation of the mechanical fuel pump, only one of the distributor valves is held in an open position by flat-faced distributor cam lobe 24 at any one time. When the distributor valve is in its open position the pump plunger 5 moved upwardly through a delivery stroke, and fuel passes around valve 51 through delivery duct 14 to the delivery valve via drilling 18 extending through distributor valve bushing 15. Annular groove 17 permits passage of the fuel around the distributor valve plunger when it is in the open position. Groove 17 therefore forms a continuation of delivery passage 18. From there the fuel passes via annular channels 31 and 32 to drilling 33 into the bore of delivery valve body 20.The fuel which is under pressure forces delivery valve 19 against spring 21 off its seat and thereafter flows from the distributor through the passage provided in fitting 22.

The same sequence of events occurs each time distributor cam 23 provided with cam lobe 24 moves each of the distributor valves to an open position.

Each of the distributor valves is held in an open position connecting the channel 18 throughout the entire delivery stroke of pump plunger 5. The diameter of the distributor cam would of course be increased with an increasing number of distributor valves, and the number of distributor valves would equal the number of cylinders in the multi-cylinder engine in which the injection fuel pump is to be used.

According to another embodiment of the invention, Figure 11 shows a different distributor valve arrangement which operates on the same principle as that shown in Figures 1 to 10. A mechanical fuel pump generally indicated at P2 includes distributor valves 65 which operate in the same manner as the distributor valves 16. However, according to this embodiment, each distributor valve cylinder 66 is simply a bore within the pump casing itself and does not include a bushing.

Each distributor valve 65 reciprocates with a close fit in its bore.

Fuel is metered and pumped by a pumping unit (not shown) through fuel delivery passage 67 to the cylinder bore. When the distributor valve is in a closed position, i.e., its lowermost position, no fuel can pass around the distributor valve plunger.

However, when the distributor valve plunger is in its upper open position, fuel flows around groove 71 to passage 69, which in this embodiment extends laterally rather than vertically of the distributor assembly.

Threaded into the side of the pump casing is a nipple 73 having an internal passage 75 which is connected to passage 69. Fitted into nipple 73 is a tubular fitting 77 provided with a delivery passage 79. Delivery passage 79 is in turn connected to passage 75. When distributor valve 75 is in its open position, the fuel passing around annular groove 71 flows through lateral passages 69 and 75 and upwardly through vertical delivery passage 79.

WHAT I CLAIM IS: 1. A distributor assembly for use with a pump unit metering and pumping fuel to said distributor assembly, said distributor assembly being provided with a plurality of distributor valves including valve plungers which distribute fuel to the cylinders of a multi-cylinder internal combustion engine, a distributor cam having a single raised flat distributor lobe for orbiting between and moving said valve plungers in succession from a non-distributing to a stationary distributing position and for holding said valve plungers in said distributing position during the pumping of fuel to said assembly, spring means for returning said valve plungers to said non-distributing position and a plurality of fuel delivery ducts extending to said distributing valves, each of said distributor valves distrbuting in succession fuel to its respective cylinder.

2. A distributor assembly as claimed in Claim 1, wherein said distributor valves include bored distributor valve bushings with said valve plungers reciprocating in succession in a close fit in said bores of said valve bushings, said delivery ducts extending through said bushings and being interrupted by said distributor valve plungers when in their non-distrbuting positions, said valve plungers being provided with annular grooves which align with said delivery ducts when said valve plungers are in their distributing positions to permit the flow of fuel around said valve plunger from the pump unit to the cylinders of the multicylinder internal combustion engine.

3. A distributor assembly as claimed in Claim 2 wherein said distributor valves are arranged about said pump unit, said valve plungers are cylindrical in shape and said

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. groove 17 is in alignment with drilling 18 through the entire upstroke of plunger 5. Returning to Figure 4, the pump housing, which may contain a governor (not shown) includes a control lever shaft 48. A pump control lever 49, which may be operated manually is connected with positioning rack 10 through intermediate linkage 46 and intermediate lever 47 mounted on the control lever shaft. The fuel output of the fuel pump is determined by the positioning of the pump control lever 49, which may be positioned to provide for a maximum or minimum R.P.M. position. The pump control lever is held in idle position by idle stop piston screw 45, which may be pressed inwardly to permit the control rack to be moved to a stop or neutral position in which no fuel is delivered. In summarizing the operation of the mechanical fuel pump, only one of the distributor valves is held in an open position by flat-faced distributor cam lobe 24 at any one time. When the distributor valve is in its open position the pump plunger 5 moved upwardly through a delivery stroke, and fuel passes around valve 51 through delivery duct 14 to the delivery valve via drilling 18 extending through distributor valve bushing 15. Annular groove 17 permits passage of the fuel around the distributor valve plunger when it is in the open position. Groove 17 therefore forms a continuation of delivery passage 18. From there the fuel passes via annular channels 31 and 32 to drilling 33 into the bore of delivery valve body 20.The fuel which is under pressure forces delivery valve 19 against spring 21 off its seat and thereafter flows from the distributor through the passage provided in fitting 22. The same sequence of events occurs each time distributor cam 23 provided with cam lobe 24 moves each of the distributor valves to an open position. Each of the distributor valves is held in an open position connecting the channel 18 throughout the entire delivery stroke of pump plunger 5. The diameter of the distributor cam would of course be increased with an increasing number of distributor valves, and the number of distributor valves would equal the number of cylinders in the multi-cylinder engine in which the injection fuel pump is to be used. According to another embodiment of the invention, Figure 11 shows a different distributor valve arrangement which operates on the same principle as that shown in Figures 1 to 10. A mechanical fuel pump generally indicated at P2 includes distributor valves 65 which operate in the same manner as the distributor valves 16. However, according to this embodiment, each distributor valve cylinder 66 is simply a bore within the pump casing itself and does not include a bushing. Each distributor valve 65 reciprocates with a close fit in its bore. Fuel is metered and pumped by a pumping unit (not shown) through fuel delivery passage 67 to the cylinder bore. When the distributor valve is in a closed position, i.e., its lowermost position, no fuel can pass around the distributor valve plunger. However, when the distributor valve plunger is in its upper open position, fuel flows around groove 71 to passage 69, which in this embodiment extends laterally rather than vertically of the distributor assembly. Threaded into the side of the pump casing is a nipple 73 having an internal passage 75 which is connected to passage 69. Fitted into nipple 73 is a tubular fitting 77 provided with a delivery passage 79. Delivery passage 79 is in turn connected to passage 75. When distributor valve 75 is in its open position, the fuel passing around annular groove 71 flows through lateral passages 69 and 75 and upwardly through vertical delivery passage 79. WHAT I CLAIM IS:

1. A distributor assembly for use with a pump unit metering and pumping fuel to said distributor assembly, said distributor assembly being provided with a plurality of distributor valves including valve plungers which distribute fuel to the cylinders of a multi-cylinder internal combustion engine, a distributor cam having a single raised flat distributor lobe for orbiting between and moving said valve plungers in succession from a non-distributing to a stationary distributing position and for holding said valve plungers in said distributing position during the pumping of fuel to said assembly, spring means for returning said valve plungers to said non-distributing position and a plurality of fuel delivery ducts extending to said distributing valves, each of said distributor valves distrbuting in succession fuel to its respective cylinder.

2. A distributor assembly as claimed in Claim 1, wherein said distributor valves include bored distributor valve bushings with said valve plungers reciprocating in succession in a close fit in said bores of said valve bushings, said delivery ducts extending through said bushings and being interrupted by said distributor valve plungers when in their non-distrbuting positions, said valve plungers being provided with annular grooves which align with said delivery ducts when said valve plungers are in their distributing positions to permit the flow of fuel around said valve plunger from the pump unit to the cylinders of the multicylinder internal combustion engine.

3. A distributor assembly as claimed in Claim 2 wherein said distributor valves are arranged about said pump unit, said valve plungers are cylindrical in shape and said

distributdr valve bushings include annular grooves for collecting fuel seeping along the sides of said valve plungers.

4. A distributor assembly as claimed in Claim 3 further including a plurality of delivery valves, each having a bored delivery valve body with an annular channel in communication with a delivery duct and a fuel passage extending from the said annular channel to said bore of said delivery valve body, said delivery valves being spring loaded to a closed position in said bores of said delivery valve body and moving to a delivery position when under pressure from fuel distributed by said distributor assebly.

5. A distributor assembly substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.