GB2248274A

GB2248274A - I.c. engine fuel supply manifold

Info

Publication number: GB2248274A
Application number: GB9120374A
Authority: GB
Inventors: Alfredo Terzi; Flavio Giovannini
Original assignee: Weber SRL
Current assignee: Weber SRL
Priority date: 1990-09-28
Filing date: 1991-09-25
Publication date: 1992-04-01
Anticipated expiration: 2011-09-25
Also published as: GB2248274B; GB9120374D0; IT9067731A1; FR2667360B1; DE4131967C2; FR2667360A1; IT1241694B; DE4131967A1; IT9067731A0

Abstract

The manifold is formed of a tube 1 with injector connectors 2 and an inner tube 3 defining a supply duct 8 therebetween and has a fuel pressure regulator 7 and a diaphragm 14 for damping fuel pressure fluctuations in the supply duct. The location of the regulator 7 and the diaphragm 14 and the orientation of the manifold fuel supply and discharge connectors 22, 23 may vary (Figs. 2 to 4). <IMAGE>

Description

1 c 1 TUEL SUPPLY MANIFOLD FOR A SUPPLY LINE FOR AN INTERNAL COMBUSTION

ENGINE, OF THE TYPE HAVING ELECTROMAGNETICALLY-OPERATED FUEL METERING AND ATOMISING VALVES" The present invention relates to a fuel supply manifold for a supply line for an internal combustion engine which is arranged to supply fuel under pressure to a plurality of electromagnetically-operated fuel metering and atomising valves.

Manifolds of this type normally include a first tubular body which has a plurality of connectors f or the said valves and a second tubular body, normally disposed within the first and defining therewith a duct for supplying the fuel to the connectors, the duct being bounded by the inner and outer surfaces of the first and second tubular bodies respectively.

Such manifolds also include a pressure regulator which is arranged to keep the fuel pressure in the supply duct at a predetermined value; the regulators comprise essentially an inlet port and an outlet port for the fuel which communicate with the fuel supply duct def ined above and with a discharge duct for the fuel respectively, and an obturator member arranged to allow the fuel to flow 2 from the inlet port to the outlet port when the pressure in the supply duct exceeds a predetermined value. The pressure regulator is normally disposed in a seat in the manifold.

Manifolds of the type described above have the disadvantage that they do not provide a correct supply of fuel to the metering and atomising valves, particularly when the manifolds are used in supply lines in which the opening phases of the fuel metering and atomising valves occur simultaneously in all cylinders of the engine. Indeed, in any case of this type of operation, since the pump which supplies the fuel causes sharp, rapid pressure oscillations in the supply duct to the manifold, is vibrations, that is pressure waves, may be triggered in the fuel within the manifold itself and, not being damped by the pressure regulator, impede its operation and consequently have a harmful effect on the supply of fuel to the metering and atomising valves.

The object of the present invention is to provide a manifold of the type just indicated which eliminates the disadvantage described above.

Another object of the invention is to provide a manifold of the type indicated which is very compact, of small bulk and is consequently quick and simple to install in 3 an engine of a motor vehicle.

These objects are achieved by means of a fuel supply manifold for a fuel supply line for an internal combustion engine which is arranged to supply fuel under pressure to a plurality of electromagnetically-operated fuel metering and atomising valves, comprising essentially; a f irst tubular body having a plurality of connectors for the valves; a second tubular body disposed within the first and defining therewith a duct for supplying fuel to connectors, the duct being bounded by the inner and outer surfaces of the first and second tubular bodies respectively; a pressure regulator for maintaining the fuel pressure in the supply duct at a predetermined value, the pressure regulator comprising essentially an inlet port and an outlet port for the fuel communicating respectively with the fuel supply duct and with a fuel discharge duct and an obturator member for allowing the fuel to flow from the inlet port to the outlet port when the pressure in the supply duct exceeds a predetermined value, the pressure regulator being disposed in a seat in the manifold; characterised in that it includes:

a vibration damping unit for damping the pressure 4 waves in the fuel in the supply duct, the unit comprising essentially a deformable diaphragm acted upon by a spring, the diaphragm forming one wall of the fuel supply duct so that vibrations in the fuel within the duct are damped by the deformation of the diaphragm.

In order to provide a better understanding of the structure of the supply manifold of the invention, a more detailed description of the manifold itself will now be given, by way of example, with reference to the appended drawings in which:

Figures 1 to 4 show longitudinal sections of various embodiments of the supply manifold of the invention.

With reference first of all to Figure 1, the manifold of the invention comprises essentially a first tubular body 1 having a plurality of connectors 2 each of which is arranged to enable the connection of an electromagnetically-operated fuel metering and atomising valve of known type. The manifold also includes a second tubular body 3, within the first and substantially coaxial therewith, which, together with the first tube, defines a duct 4 for supplying fuel to the connectors 2; the said duct is bounded by the inner surface 5 and the outer surface 6 respectively of the tubular bodies 1 and 3.

A pressure regulator generally indicated 7, of known type, forms part of the manifold of the invention and is arranged to keep the f uel pressure in the duct 4 at a predetermined value; the regulator comprises essentially a casing 8 formed with an inlet port 7i and an outlet port 7u for the fuel which communicate respectively with the supply duct 4 and with a fuel discharge duct 9 which, in the embodiment of Figure 1, is formed within the second tubular body 3. The pressure regulator 7 also includes an obturator member (not shown) housed within the casing 8 and arranged to allow fuel to flow from the inlet port 7i to the outlet port 7u when the pressure in the supply duct 4 exceeds a predetermined value.

In the embodiment of Figure 1, the pressure regulator is housed in a seat 10 in the tubular body 1 and is f ixed therein by means of a suitable collar 11.

In accordance with the invention, the manifold includes a vibrationdamping unit generally indicated 13 which is arranged to damp vibrations in the fuel within the duct 4; this unit comprises essentially a deformable diaphragm 14 acted upon by a spring 15; these two members are located within a cup-shaped body 16 which, in the embodiment of Figure 1, is fixed to the end of the tubular body 1 which is opposite that to which the pressure regulator 7 is fixed.

is 6 In accordance with the invention, the damping unit 13 is disposed in the manifold in such a manner that the diaphragm 14 essentially forms one wall of the fuel supply duct 4 and any vibrations which occur in the fuel within the duct itself are damped by the deformation of the diaphragm. Conveniently, two discs 17 are fixed to the central part of the diaphragm, one of the discs providing an abutment for one end of the spring 15 while the other is arranged to bear on a stop rod 18 when the damping unit is in the rest condition shown in Figure 1.

Moreover, the periphery of the diaphragm 14 bears against an annular seat 19 at the said end of the tubular body 1 and the edge of the cup-shaped body 16 is bent back towards the seat itself so as to clamp it to the manifold together with the diaphragm.

In the embodiment of Figure 1, the first tubular body comprises two interconnected parts indicated la and ib; the second of these includes, essentially, a portion of a supply duct 20 and a pair of discharge ports 21 connected to the duct 9 within the second tubular body 3. As is clearly seen in Figure 1, the damping unit 13 is fixed to one end of the part la while the pressure regulator 7 is fixed to one end of the part lb.

The manifold also includes a fuel inlet connector 22 7 which communicates with the supply duct 4 and a discharge connector 23 connected to the ports 21: in the embodiment of Figure 1, the axes of the inlet and discharge connectors are parallel to each other and disposed at the right-hand end of the manifold.

In the embodiments of Figures 3 and 4, the damping unit 13 is fixed to the seat 10 formed at one end of the part la of the first tubular body 1 while the pressure regulator 7 is fixed in a second seat 26 formed in the part lb of the body; the axes of the seats 10 and 26 are perpendicular to each other. In the embodiment of Figures 3 and 4, the second tubular body 3 puts the fuel supply duct 4 in communication with the inlet port 7i of the pressure regulator 7; for this purpose, the left-hand end of the body 3 is located at a certain distance from the diaphragm 14 of the damping unit 13 and the righthand end of the body communicates with the ports 27 formed in the part lb which in turn communicate with the inlet port 7i of the pressure regulator 7.

Moreover, the seat 10 of the damping unit 13 houses a bush 28 for keeping the left-hand end of the tubular body 3 centred and for constituting a stop for the diaphragm 14 of the damping unit 13.

The fuel supply duct 4 communicates with a fuel inlet 8 connector 29 formed in the part lb; fuel discharge ports 30 are formed in this same part and communicate with a discharge connector 31.

The embodiments 3 and 4 differ from each other solely in the f orm of the part lb of the tubular body 1; in the embodiment of Figure 3, the righthand end of the tubular body 3 is inserted in a seat 32 formed in the part lb while in the embodiment of Figure 4, a sleeve 33 projecting axially from the part lb is inserted in the right hand-end of the tubular body 3; moreover, in the two cases, the angles between the axes of the inlet and outlet connectors 29 and 31 differ.

The embodiment of Figure 2 differs from that of Figure 1 solely in the form of the part lb of the tubular body 1; in fact, while in Figure 1 the outlet connector 23-is perpendicular to the axis of the part 1b and is parallel to that of the inlet connector 22, in the embodiment of Figure 2, the axes of the inlet and outlet connectors 22 and 23 are not parallel to each other nor to the longitudinal axis of the manifold.

The manifold described above operates as follows. The fuel is supplied to the supply duct 4 through the inlet connector 22 and from this duct passes through the connectors 2 to the fuel metering and atomising valves; 9 when the pressure in the duct 4 exceeds a predetermined value, the obturator member (not shown) of the pressure regulator 7 puts the inlet port 7i in communication with the outlet port 7u of the regulator itself and hence a certain quantity of fuel may be delivered to the exhaust through the discharge duct 9, the ports 21 and the connector 23.

When there are sharp, rapid variations in the fuel pressure in the duct 4, triggered for example by a high rate of flow of the fuel which is to be supplied to the fuel metering and atomising valves whenever these initiate the injection phases at the same instant, or because of sharp pressure variations generated by the fuel-supply pump, the damping unit 13 can intervene to damp these vibrations. Since the diaphragm 14 of this unit constitutes essentially a wall of the fuel supply duct 4, the pressure reigning at any instant within the duct acts on this diaphragm: hence, when vibrations are triggered, these are damped by the deformability of the diaphragm itself which is loaded by the spring 15 and which, essentially, allows the volume of the supply duct 4 to increase by small amounts.

The operation of the manifold of the embodiments of Figures 3 and 4 is similar to that just described and may easily be determined from the drawings themselves.

It is clear that the described embodiments of the present invention may be modified and varied, both in form and in the arrangement of the various parts, without thereby departing from the scope of the invention.

11

Claims

1.. A fuel supply manifold f or a fuel supply line f or an internal combustion engine which is arranged to supply fuel under pressure to a plurality of electromagnetically-operated fuel metering and atomising valves, comprising essentially; a first tubular body (1) having a plurality of connectors (2) for the valves; a f irst tubular body (1) having a plurality of connectors (2) for the valves; a second tubular body (3) disposed within the first and defining therewith a duct (4) for supplying the fuel to the connectors, the duct being bounded by the inner surface (5) and the outer surface (6) respectively of the first and second tubular bodies; a pressure regulator (7) for maintaining the fuel pressure in the supply duct (4) at a predetermined value, the pressure regulator comprising essentially an inlet port (7i) and an outlet port (7u) for the fuel - communicating respectively with the fuel supply duct (4) and with a fuel discharge duct (9) and another obturator member for allowing the fuel to flow from the inlet port (7i) to the outlet port (7u) when the pressure in the supply duct exceeds a predetermined value, the pressure regulator being disposed in a seat (10) in the manifold; 12 characterised in that it includes:

a vibration damping unit (13) for damping the pressure waves in the fuel in the supply duct (4), the unit comprising essentially a deformable diaphragm (14) acted apon by a spring (15), the diaphragm forming one wall defining the fuel supply duct (4) so that the vibrations in the fuel within the duct are damped by the deformation of the diaphragm (14).

2. A manifold according to claim 1 characterised in that the damping unit (13) is f ixed to one end of the first tubular body (1) so that the diaphragm (14) of the unit defines one end of the supply duct.

3. A manifold according to claim 1, characterised in that the damping unit (13) includes a cup-shaped housing (16) which houses the spring (15) and against the edge of which bears the diaphragm (14), the housing being fixed to an annular seat (19) at the end of the first tubular body 1.

4. A manifold according to one of the preceding claims, characterised in that the first tubular body (1) includes two interconnected parts (1a and 1b), the pressure regulator (7) being f ixed in a seat (10) formed at one end of a f irst (1a) of the parts of the f irst tubular body (1) and the damping unit (13) being f ixed to one end 13 of the second (ib) of the parts of the first tubular (1) -

5. A manifold according to claim 4, characterised in that the outlet port of the pressure regulator (7u) communicates with the chamber within the second tubular body (3) which forms the fuel discharge duct (9).

6. A manifold according to claim 4 or claim 5, characterised in that the second tubular body (3) communicates with dispharge ports (21) formed in the second part (1b) of the tubular body (1).

is

7. A manifold according to one of claims 1 to 3, characterised in that the first tubular body (1) includes two interconnected parts (1a, 1b), the damping unit (13) being fixed to a first seat (10) formed at one end of a first (1a) of the parts of the first tubular body (1) and the pressure regulator (13) being fixed in a second seat (2 6) in the second (ib) of the parts of the first tubular body (1), the axes of the seats (10, 26) being perpendicular to each other.

8. A manifold according to claim 7, characterised in that the second tubular body (3) puts the fuel supply duct (4) into communication with the inlet port (7i) of the pressure regulator (7), the fuel discharge port (30) 4 j - 14 being formed in the second part (1b) of the f irst tubular body (1).

9. A fuel supply manifold for a fuel supply line of an internal combustion engine, substantially as described and illustrated in the appended drawings.