CA1070562A - Device for supplying fuel to injectors of a combustion engine - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A device for supplying fuel to injectors of a combustion engine.
Said device is improved, particularly with regard to the control and the adjustment of the quantity of fuel pumped and the simplicity of construction of the device in that stop means in-cludes an axially shiftable wedge member and means for axially shifting said wedge member, a control rod and a stop at one end of said control rod which engages said wedge, said control rod passing axially through said wedge member and fixed at its free end to said means for axially shifting, spring means urging said wedge against said stop, said wedge member receiving said control rod with clearance to allow said control rod to rotate with res-pect thereto while allowing said wedge member to shift laterally with respect to said control rod.

Description

~.0705~Z

The invention relates to a device for supplying fuel to injectors of a combustion engine.
The invention has for its object to provide a further improvement of the prior device, particularly with regard to the control and the adjust-ment of the quantity of fuel pumped and the simplicity of construction of the device.
The invention provides in a device for supplying fuel to an atomizer of a combustion engine, a housing having a cylinder therein, a coupling member having an abutment member, a displacer body slidably received in said cylin-der and defining a pump chamber therewith, said displacer body being connect-ed to said coupling member in offset relation to said abutment member, drive means for moving said coupling member back and forth to reciprocate said displacer body within said cylinder, rigid stop means for engagement by said abutment member to limit movement of said coupling member and thereby control the stroke of said displacer body, inlet valve means for allowing fuel to flow into said pump chamber as said displacer body moves in that direction increa~ing the volume of said chamber, and outlet valve mPans for allowing fuel to 10w out of said pump chamber when the displacer body is moved in the opposlte direction to decrease the volume of said pump chamber, the improve-ment wherein: said stop means includes an axially shiftable wedge member and means for axially shifting said wedge member, a control rod and a stop at one end of said control rod which engages said wedge, said control rod passing axially through said wedge member and fixed at its free end to said means for axially shifting, spring means urging said wedge against said stop, said wedge member receiving said control rod with clearance to allow said control rod to rotate with respect thereto while allowing said wedge member to shift laterally with respect to said control rod.
The many steps to be taken in accordance with the invention, pre-ferably applied in conjunction, are disclosed in the Claims and will be explained in the following description with reference to a drawing. In the drawing:

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Figure 1 is a perspective elevation, partly broken away, of a preferred embodiment of a device in accordance with the invention, Figure 2 is a plan view, partly broken away, of the device of Figure 1, Figure 3 is a sectional view taken on the line III-III in Figure 2, Figure 4 is a sectional view taken on the line IV-IV in Figure 3, showing schematically the connection with a combustion engine, Figure 5 is an enlarged sectional view of a detail V in Figure 4, Figure 6 shows an electrical circuit diagram for use in the device of Figure 1, Figure 7 is an enlarged sectional view taken on the line VII-VII
in Figure 2, Figure 8 (on the first sheet of drawings) is an enlarged, longitu-dinal sectional view of a detail VIII in Figure 2, Figure 9 (on the first sheet of drawings) shows on an enlarged scale a detail IX of Figure 8, Figure 10 (on the first sheet of drawings) is a sectional view corresponding to Figure 9 in the dismounted state, and Figure 11 shows a variant of detail XI in Figure 1.
The device 1 comprises a cast or spray-cast aluminium frame 3.
Magnet plates 5 are stacked up in a jig and interconnected at their outer edges by glue 7. Two pairs of electromagnets 2 are firmly secured by means of bolts 6 between the

-3-1071~562 frame 3 and a lid 4. Each of the electro-magnets 2 comprises a core 10 formed by a packet of magnet plates 5 and an energi~ing coil 14 surrounding said core 10. Beneath each electro-magnet 2 the frame 3 has a wide air passage 8 allowing air to pass for cooling the electro-magnets 2. A plate-shaped armature 18 is adapted to reciprocate between each pair of alternately energized magnets 2. Each armature 18 is pivoted by an end 9 in a slot 13 of a bearing element 11 of synthetic resin, preferably Arnite, embedded in a bearing block 12, which is integral with the frame 3.
At the free end 15 each armature 18 holds a cross-shaped coupling member 20, with which are connected two displacer bodies 22 of two fuel pumps 32. The stroke of the displacer bodies 22 is determined by adjustable actuating means arranged on either side of the coupling members 20 and formed by two wedges 26 and 33.
Each pump 32 comprises a pump chamber 29 accommodated in a pump housing 42 and having a fuel inlet 27 and a fuel outlet 28, each of them leading to an atomizer 30 of a combustion enqine 31. The inlet valve 39 and the outlet valve 41 are arranged in a separate valve housing 43, to be arran~ed in the housing 42, said valve 20 housing comprising three parts to be interconnected i.e. an inlet seat 44 , a tube 45 secured to the former by cement 160 and an outlet seat 46 secured in place in said tube 45 by cement 17.
The inlet seat 44 to be connected with a fuel supply pump 40 has at the beginning a filter 49 of filter gauze and an annular groove 19 receiving a seal 50 for isolation from the pumn housing 42. The tube 45 has an external annular groove 51 and a channel 52, through which the space 53 of the valve housing 43 between the inlet valve 39 and the outlet valve 41 communicates with the pump chamber 29.

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The tube 45 has a further annular groove 55 receiving a seal 56.
All valve housings 43 are simultaneously enclosed in the pump housing 42 by means of a lid 100 with the interposition of a layer of elastic material 101. In order to avoid penetration of soil into the valve housing 43, particularly when the valve housing 43 as a unit is still located outside the pump housing 42 the fuel inlet 27 as well as each fuel outlet is provided with a filter. For example, a cylindrical filter 102 of filter gauze is arranged in the recess 51 and a filter 103 of filter gauze is enclosed in the fuel outlet 104 with the aid of a valve sto~ 105, which limits the maximum height of elevation of the outlet valve 41 and which is formed by a sleeve having radial recesses 106. The inlet valve 39 and the outlet valve 41 com~rise each a valve body 78 of a synthetic resin and a conper supporting ring 57 for a valve spring 58.
Into each pump housing 42 is pressed a hard steel cyllnder 59 with close forced fit. The pump housings 42 are pairwise arranged coaxially opposite one another and spaced apart from one another by the front faces 60 of the cylinders 59 by means of connecting members by a distance t. Thesé connecting members are formed by fitting pins 61 and tapped sleeves 62, rigidly connecting the pump housings 42 with the frame 3. The front faces 60 are accurately held in relatively parallel positions by means of the fitting pins 61. The tapped sleeves 62 constitute in addition the connecting nipples for the fuel supply conduits 107 and the fuel return conduits 108 leading to the tank 99 and a pressure control-valve 152 included therein and connected with a return outlet 109. The return outlet 109 com-municates through a channel 110 of the pump chambers 29 with ~0705~;Z

the fuel inlet 27. Thus the fuel circulates at a high rate through the device 1 so that the fuel is not excessively heated in the device 1. It is therefore possible to mount the device 1 at a fairly hot place, for example, directly on the combustion engine 31.
In each of the two pump housings 42 a vent screw 98 common to two pump chambers 29 seals a vent channel 97, which opens out at the top of the pump housings 42 so that the emerging fuel is collected in a fuel leak collecting space 96. The vent channel 97 com-municates with the pump chambers 29 through inclined channels 94.
The vent screw ~8 is covered by a screw ~5.
The displacer bodies 22 are each made of a synthetic resin, preferably a superpolyamide and are each formed by a cup-shaped piston 63, a guide collar 64 engaging the pump chamber 29 and an axially extending, elastically deformable tie member 65, whose end 92 is secured with the interposition of glue 91 in a wide bore g3 of a guide member 90 of a hard steel coupling member 20.
~wing to the clearance between the tie member 65 and the bore 93 the piston 63 with the guide collar 64 is displaceable in a radial directlon with respect to the guide member 90. The device 1 com-prises two cross-shaped coupling members 20 by which the dis-placer bodies 22 of each pair of fuel pumps 32 are coupled with one another. Each coupling member 20 is connected by means of an elastic coupling 66 with an armature 18. The elastic coupling 66 comprises an elastic ring 67, accommodated in the coupling member 20 and surrounding a pin 68 of the armature 18 and pre-ferably made of a superpolyamide.
The displaced volume of each fuel pump 32 is determined by the stroke of the coupling member 20, which is adapted to re-ciprocate by means of a ball-shaped arm 79 between the wedges 26 ~C~7~56Z
and 33. In order to obtain an accurate adjustment of said stroke both the coupling member 20 and the wedges 26 and 33 are made of hard steel, whilst the wedges 26 and 33 accommodated each in a guide groove 89 in a pump housing 42 are in engagement with a pump housing 42 with the interposition of a supporting layer 88 of a synthetic resin, preferably Arnite (Trademark for polyethylene tereph~halate). In order to avoid excessive wear of these parts the comparatively small overall bulk of the coupling member 20 and the two displacer bodies 22 connected with the former is separated from the com-paratively large bulk of the armature 18 by using the elastic coupling 66.
At each stroke the coupling member 20 butts against a comparatively hard stop, whilst the bulk of the armature 18 continues to move over a small distance and is arrested resiliently.
Two housing blocks 69 comprise each two joined pump housings 42, between which wedges 26 and 33 are arranged to serve as common control-means for each of the pumps 32. The distance t and the coupling members 20 are particularly small since the wedges 26 and 33 are held in guide grooves 89 of the pump housings 42 so that inaccuracies of the fuel displacements due to deformation of coupllng members and/or to mounting defects are slight. A
~atisfactory seal of the piston 63 is obtained since the guide member 90 guided in the cylinder 59 absorbs the tilting forces produced by the arm 79 forming a stop member striking a wedge 26 or 33 beyond the axial line 85 of the cylinder 59. In order to ensure a long life-time of the device 1 each guide member 90 is coated with a wear-resistant material 87, preferably Rilsan (Trademark for nylon-ll, a polyamide resulting from poly-condensation of omega-amino-undecanoic acid), which is applied by dipping and subsequently machined to the prescribed size.
In the unmounted state illustrated in Figure 10 the sealing rim 86 of the piston 63 projects radially beyond the 10705~Z

guide collar 64. The sealing rim 86 is sharp so that in the mounted state it assumes the satisfactorily sealing form shown in Figure 9 and has a long lifetime, particularly if the cylinder 59 is formed by a silver steel sleeve.
The armature 18 engages an adjustable setting me~ber extending at right angles to the direction of movement of said armature 18 and being formed by a set screw 84. The armature 18 is adapted to pivot about the axial line 85 and is turned about said axial line 85 during the mounting operation so that the end 9 enters the slot 13 open at the top in the bearing element 11 and is received between the set scre~ 84 and a spring 111 in a recess 112, the armature 18 being subsequently urged against the set screw 84, which closes the slot 13. By means of the set screw 84 ~ the amplitude of the armature 18 turning about the axial line 85 is adjusted and hence the spot of engagement of the ball-shaped arm 79 on the stop faces of the wedges 26 and 33 extending obliquely to the reciprocatory movement of the armature 18.
The wedge 26 is driven by a piston 80 of a control-cylinder 73 communicating downstream of an air inlet valve 113 with the air inlet manifold 72 of a combustion engine 31. The control-cylinder 73, the length of which is held at a minimum, is centered with respect to the frame 3 by means of a centering disc 114, which extends into the bore 115 of the control-cylinder 73 and in a centering hole 116 of the frame 3. The control-cylinder 73 is adapted to turn about the centering disc 114 and to be fixed in the desired position by clamping means formed by cla~ping screws 117 and clamps 119 engaging an external groove 118 of the control-cylinder 73.
The top side of the control-cylinder 73 communicates through re-cesses 121 in the centering disc 114 and recesses 122 in the frame 3 10705tiZ

with a fuel leak collecting space 96 so that any leakage ca~
flow via the outer side of the piston 80 and the control-cylinder 73 towards the inlet manifold 72. In order to maintain the cleanness of the control-cylinder 73 a filter of filter gauze is arranged between the centering disc 114 and the frame 3.
Externally of the control-cylinder 73, at the end remote from the wedge 26, an axially displaceable switch 82 is controlled by an extension 124 of the piston 80 for stopping the pumps 32 in the event of a drop beneath a given pressure in the inlet manifold 72. The switch 82 can be readily actuated.
A control-rod 126 extending axially across a wide bore 125 of the wedge 26 and being rigidly secured to the piston 80 is adapted to turn with respect to the wedge 26. Owing to the .. clearance between the bore 125 and the control-rod 126 and to the relative rotatability of the wedge 26 and of the control-rod 126 the high-frequency vigourous impacts of the armature 18 are hardly or not at all transferred to the piston 80.
The wedge 33 is adjustable in accordance with the engine speed. A screw rod 127 extending across the wedge 33 is adapted to turn with an amount of clearance and to be displaced in a transverse direction with respect to the wedge 33, which is urged by a spring 128 against a shoulder 129 of the screw rod 127. The top end of the screw rod 127 has a screwthread 130 engaging a screwthread piece 131 of a metal bellows barometer 133.
After evacuation the bellows 133 is closed by a nipple 132. The top end of the bellows 133 supports a diaphragm 134 of a pressure chamber 135, which communicates through a choke 136 with the inlet manifold 72. The pressure chamber 135 has an air inlet 138 controlled by an air valve 137. The air valve 137 is closed by ~7~5~Z
an electro-magnet 139, which is energized -in--accordance with the speed of the combustion engine 31. The electro-magnet 139 is each time energized unon the energization of an electro-magnet 2.
If the speed of the combustion engine 31 is high, the air valve I37 remains closed so that a high vacuu~ is produced in the pressure chamber 135, as a result of which the quantity of fuel supplied is increased. Likewise the quantity of supplied fuel increases if the barometric air pressure is high. In both cases the wedge 33 is lifted.
The pressure chamber 135 comprises a control-mem~er formed by the diaphragm 134, which is adjustably connected with the wedge 33, since the pressure chamber 135 together with the diaphragm 134 and the barometer bellows 133 is adapted to turn with respect to the screw rod 127. Since the head 140 of the screw rod 127 is prevented from turning in the guide groove 89, the starting position of the wedge 33 can be adjusted in an axial direction. After the adjustment the pressure chamber 135 is anchored by means of a safety pin 141 with respect to a holder 142.
Between the pump housings 42 and the hot electro-magnets 2 air gaps 144 are provided for heat insulation. These gaps 144 are covered by elastic stri~s 145 to prevent penetration of soil.
Each atomizer 30 has a needle 23, a conical end 21 of which is drawn by a strong spring 150 to the seat 149 so as to establish a seal. In the event of a high fuel pressure in a chamber 148 co~municating with the fuel conduit 28 and through a perforated collar 147 with a chamber 151 said end 21 is lifted fr~m the seat 149 against the action of the spring 150 (see Figure 5).
Each electro-magnet 2 is controlled by a circuitry 170 10705~Z
shown schematically in Figure 6. The transistors TR1 and TR2 to-gether with the associated resistors Rl, R2, R3, R4 and R5 and with the capacitor C constitute a monostable multivibrator. The resistor R1 and the capacitor C determine the time constant. The collector output of the transistor TR2 constitutes via the resistor R4 the input of the transistor TR3, which serves as an amplifier for the current to be passed through the coil Ll of the electro-magnet 2.
Across the coil Ll is connected a quench diode Dl. To the input terminals Kl and K2 is connected a current soucre 35, whereas - 10 the input K3 serves for the supply of a control-pulse, which may originate from a pulse generator 34, which is coupled with the engine 31. The pulse generator 34 may be coupled with a cam shaft 163 of the combustion engine 31 and has a rotating contact lS5, which alternately comes into contact with one of the four contacts 16 for the energization of the subcessive electro-magnets 2.
Each of these four contacts 16 is connected to an input terminal K3 of the circuitry 170. In this way the fuel required for each combustion cylinder is injected during each cycle of the com-bustlon engine 31 at the required instant by an atomizer 30. The order of energization of the electro-magnets 2 is chosen so that in each cycle each of the wedges 26 and 33 is briefly free of a coupling member 2a so that each of them can be displaced by a slight force. ~he switch 82 is connected between the contact 155 and the source 35 so that in disabling the switch 82 no control-pulses are given off. The electro-magnet 139 has also a circuitry 170, whose terminal K3 is connected to each of the contacts 16.
In the variant shown in Figure 11 the set screw 146 is disposed outside of the bearing element 11 on the bottom side of the armature 18, whereas the spring 111 is arranged on the top side.

Claims (2)

THE EMBODIMENTS OF THE INVENTION FOR WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a device for supplying fuel to an atomizer of a combustion engine, a housing having a cylinder therein, a coupling member having an abutment member, a displacer body slidably received in said cylinder and defining a pump chamber therewith, said displacer body being connected to said coupling member in offset relation to said abutment member, drive means for moving said coupling member back and forth to reciprocate said displacer body within said cylinder, rigid stop means for engagement by said abutment member to limit movement of said coupling member and thereby control the stroke of said displacer body, inlet valve means for allowing fuel to flow into said pump chamber as said displacer body moves in that direction increasing the volume of said chamber, and outlet valve means for allowing fuel to flow out of said pump chamber when the displacer body is moved in the opposite direction to decrease the volume of said pump chamber, the improvement wherein:
said stop means includes an axially shiftable wedge member and means for axially shifting said wedge member, a control rod and a stop at one end of said control rod which engages said wedge, said control rod passing axially through said wedge member and fixed at its free end to said means for axially shifting, spring means urging said wedge against said stop, said wedge member receiving said control rod with clearance to allow said control rod to rotate with respect thereto while allowing said wedge member to shift laterally with respect to said control rod.

2. In a device as defined in claim 1 wherein said spring means surround said rod and acts between said wedge member and said means for axially shifting.