GB2248273A

GB2248273A - I.c. engine fuel supply manifold

Info

Publication number: GB2248273A
Application number: GB9120373A
Authority: GB
Inventors: Giuseppe Risi; Mauro Mengoli
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: FR2667361A1; IT9053267V0; DE4131952A1; GB9120373D0; FR2667361B3; IT220614Z2; GB2248273B; IT9053267U1

Abstract

The supply manifold comprises a tube 1 having injector connectors 2, an inner tube 3 defining a fuel supply duct 4 therebetween and a pressure regulator 7 for maintaining a constant pressure in the fuel supply duct. The second tube 3 is made from an elastically-deformably plastics material to absorb pressure fluctuations in the duct 4. <IMAGE>

Description

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1 "FUEL SUPPLY MANIFOLD WITH A VIBRATION-DAMPING ACTION FOR A FUEL SUPPLY LINE OF AN INTERNAL COMBUSTION ENGINE" The present invention relates to a fuel supply manifold for the supply line of 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 having a plurality of connectors for the said valves and a second tubular body disposed within the first and defining therewith a duct for supplying the fuel to the is connectors, the duct being bounded by the inner and outer surfaces respectively of the first and second tubular bodies.

Manifolds of this type also include a pressure regulator for maintaining the fuel pressure within the supply duct at a predetermined value. The regulator comprises essentially an inlet port and an outlet port for the fuel communicating respectively with the supply duct and with the chamber within the second tubular body; this chamber communicates with the exhaust. The fuel is supplied to the supply duct defined between the first and second tubular bodies through an inlet connector; when the 1 2 pressure in this duct exceeds a predetermined value, a certain quantity of fuel is discharged through the pressure regulator into the chamber within the second tubular body to be discharged to the exhaust; for this purpose, the pressure regulator has an obturator member which is arranged to allow fuel under pressure to flow from the inlet port to the outlet port of the regulator itself when the fuel pressure in the supply duct exceeds a predetermined value.

Supply manifolds of the type described in brief have the disadvantage that they do not enable fuel to be,supplied correctly to the fuel metering and atomising valves whenever these valves are operated so as to initiate the fuel injection phases in the respective cylinders simultaneously, or when sudden, sharp pressure variations occur in the supply duct to the manifold. In these cases, it is found that vibrations are triggered in the fuel within the manifold with the consequence that the fuel injection into the cylinders is irregular and nonuniform.

The object of the present invention is to provide a fuel supply manifold of the type described in brief, which is free from the disadvantage just mentioned and which c:an thus enable fuel to be supplied correctly to the cylinders even when the injection phases of the various i 3 f uel metering and atomising valves start at the same instant and also where there are sudden, sharp pressure variations in the fuel within the supply duct.

This object is achieved by means of a fuelsupply manif old f or a f uel supply line of an internal combustion engine for supplying fuel under pressure to a plurality of electromagnetically-operated, fuel metering and atomising valves, comprising essentially:

a first tubular body having a plurality of connectors for the valves and a second tubular body disposed within the first body and defining therewith a supply duct for supplying fuel to the connectors, the duct being bounded by the inner surface and the outer is surface of the first and second tubular bodies respectively; a pressure regulator for maintaining the fuel pressure within 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 supply duct and with the chamber within the second tubular body, the second tubular body communicating with the exhaust, characterised in that:

the second tubular body is made from an elastically deformable material so as to allow the volume andlor shape of the fuel supply duct to vary when sudden, sharp pressure variations occur within it.

4 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 drawing in which Figure 1 is a longitudinal section through a supply manifold of the invention and Figure 2 is an end view thereof.

With ref erence to the drawing, the supply manifold of the invention comprises essentially a tubular body 1 having a plurality of connectors 2 for electromagnetically- 1 operated, fuel metering and atomising valves, known per se and not therefore shown. The manifold also includes a second tubular body 3 disposed within the f irst and defining therewith a fuel supply duct 4 in communication with the connectors 2 and bounded by the inner surface 5 and the outer surf ace 6 of the tubular bodies 1 and 3 respectively.

A pressure regulator 7 forms part of the manifold of the invention and is arranged to keep the fuel pressure within the duct 4 at a predetermined value; this regulator comprises essentially an inlet port 8 and an outlet port 9 for the fuel communicating respectively with the supply duct 4 and with the chamber 10 within the second tubular body 3. The pressure regulator 7, which is known per se, comprises essentially a housing in which an obturator member is movable, the member being arranged to keep the passage between the inlet port 8 and the outlet port 9 normally closed when the fuel pressure within the supply duct 4 is below a predetermined value and to open this passage when the pressure exceeds the said value.

Conveniently, the pressure regulator 7 is housed within a seat 13 formed in one end of the first tubular body 1.

One end of the second tubular body 3 is coupled to a connector 14 of the pressure regulator 7 into which the outlet port 9 opens while the other end of the second tubular body 3 is coupled to a bush 15 in which a discharge port 16 is formed which communicates with a corresponding exhaust connector 17.

Conveniently, the bush 15 is housed in a sleeve 18 inserted in a cooperating seat 19 in the other end of the first tubular body 1. Moreover this latter body has an inlet connector 20 for the supply of fuel to the supply duct 4; conveniently, the sleeve 18 is attached to the tubular body 1 by means of a bracket 21 with arms 22, 23 and 24: the first of these arms has an aperture in which the inlet connector 20 is inserted, the second has a recess in which the connector 17 is inserted while the third arms 24 embrace the sleeve 18.

6 In accordance with the invention, the second tubular body 3 is made from an elastically-deformable material so as to allow the volume and/or shape of the fuel supply duct 4 to vary when sudden sharp pressure variations occur within it.

Conveniently the material is a rubber mixture, an elastomer or a thermoplastics resin.

The manifold described operates as follows. Fuel is supplied under pressure through the inlet connector 20 to the supply duct 4; the fuel can then reach the fuel metering and atomising valves through the corresponding connectors 2. When the pressure in the supply duct 4 exceeds a predetermined value, it acts on the pressure regulator 7 to cause the obturator member of this regulator to move so as to open the fuel passage between the inlet duct 8 and the outlet duct 9: thus a certain quantity of fuel flows into the chamber 10 within the tubular body 3 and from there through the port 16 and the outlet connector 17 to the exhaust.

Should the pressure variations in the fuel be sudden and very high, such as those caused by the fuel-supply pump which supplies the fuel to the manifold, or whenever the supply device is arranged so that the injection cycles for the fuel metering and atomising valves start at the 9 7 same instant, the tubular body 3 def orms elastically because of the deformability of the material of which it is made; thus the correct pressure is re-established in the supply duct 4 almost instantaneously and prevents the triggering of vibrations in the fuel itself. Thus the second tubular body 3, as well as allowing fuel to be discharged from the pressure regulator 7 to the exhaust connector 17, also acts effectively to damp vibrations and regulate the pressure: this action is due to the elastic deformation of the wall of the tubular body 3, a deformation which occurs substantially radially.

1 Clearly modifications and variations may be made to the embodiment of the present invention described, both in the form and in the arrangement of the various parts, without thereby departing from the scope of the invention itself.

8

Claims

1. A fuel supply manifold for a fuel supply line of an internal combustion engine for supplying 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 and a second tubular body (3) disposed within the first body and defining therewith a supply duct for supplying fuel to the connectors, the duct being bounded by the inner surface (5) and the outer surface (6) of the first and second tubular bodies is respectively; a pressure regulator (7)f or maintaining the fuel pressure within the supply duct (4) at a predetermined value, the pressure regulator comprising essentially an inlet port (8) and an outlet port (9) for the fuel communicatingrespectively with the supply duct (4) and with the chamber (10) within the second tubular body (3), the second tubular body (3) communicating with the exhaust. characterised in that:

the second tubular body (3) is made from an elastically def ormable material s6 as to allow the volume and/or shape of the fuel supply duct (4) to vary when j 1 9 sudden, sharp pressure variations occur within it.

2. A manifold according to claim 1, characterised in that the second tubular body (3) is made f rom a rubber mixture.

3. A manifold according to claim 1, characterised in that the second tubular body (3) is made from an elastomer.

4. A manifold according to claim 1, characterised in that the second tubular body (3) is made from a thermoplastics resin.

is

5. A manifold according to any one of the preceding claims, characterised in that the pressure regulator (7) is housed in a seat (13) formed in one end of the first tubular body (1), a connector (14) of the pressure regulator (7), which is formed with the discharge port (9), being fitted in a first end of the second tubular body (3) a second end of which receives a bush (15) fixed to the other end of the first tubular body (1).

6. A manifold according to claim (5), characterised in that the bush (15) is housed in a sleeve (18) f ixed to 1 the said other end of the first tubular body (1).

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