GB2248271A

GB2248271A - Introducing a fluid into another fluid flow

Info

Publication number: GB2248271A
Application number: GB9120116A
Authority: GB
Inventors: Bruce Norman Stephen Mudford
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-09-28
Filing date: 1991-09-20
Publication date: 1992-04-01
Anticipated expiration: 2011-09-20
Also published as: MX9101273A; ZA917649B; WO1992006289A1; AU8613891A; GB9021162D0; GB2248271B; GB9120116D0

Abstract

The invention relates to apparatus for providing a fluid flow, comprising means in the form of a plate (11) defining a main fluid flow passage (13) and an additional fluid flow passage (31), for admitting air where the main passage is a passage for vapourising fluid fuel, a needle valve (38) to control flow in the passage (31) and a separate device (14) which defines a venturi via portion (26, 27) of a through bore, the device being locatable in the main fluid flow passage (13) and having a plurality of through spaced apart bores extending into the venturi, which effectively comprises the main fluid flow passage when the device (14) is in the plate (11). The same plate (11) may be used with different devices (14) to cater for different flow characteristics required.

Description

VENT3RI DEVICE AND APPARATUS INCORPORATING SAME The invention relates to a venturi device and apparatus incorporating same, such as a fuel supply system of an internal combustion engine.

In a venturi, a fluid flow conduit is restricted to a narrower bore and at or near the narrow portion of the bore, an inlet is often provided to the conduit for additional fluid. Various methods have been suggested for controlling the flow of the additional fluid such as a spring loaded ball valve, the compression of the spring being adjustable to adjust the flow of air past the ball valve.

This arrangement can lead to difficulties when the assembly is desired to be adapted for different associated equipment or different operational performance.

It is accordingly an object of the invention to seek to mitigate these disadvantages.

According to a first aspect of the invention there is provided a device for insertion into apparatus for providing a fluid flow, comprising a body having a through passage defining a venturi, and a plurality of spaced apart bores extending into the through passage.

The body may be cylindrical thereof. This provides a relatively simple constructional method.

The bores may be spaced circumferentially around the body.

The body may have an external annular groove and the bores may be in the groove. This provides a relatively simple yet efficient way of feeding the bores.

The bores may be adjacent a throat of the venturi, for example just downstream thereof.

The body may have means to locate the device or insertion into apparatus providing fluid flow.

The locating means may comprise an external flange or lip projecting from the body.

The lip or flange may be at one end of the body.

The venturi may include a portion of greater diameter than the throat thereof, and these bores may open into said portion.

According to a second aspect of the invention there is provided apparatus for providing a fluid flow, comprising means defining a main fluid flow passage and an additional fluid flow passage, means to control flow of fluid in the additional fluid flow passage, and a device adapted for insertion in the main fluid flow passage and having a through passage defining a venturi and a plurality of spaced apart bores extending into the through passage, the arrangement being such that the through passage comprises the main fluid flow passage when the device is inserted in the means.

The means may comprise a plate means adapted for mounting on a fluid flow provider.

The plate means may be adapted by through holes for receiving securing means.

The main fluid passage may have locating means for the device.

The locating means may comprise a recess in the plate adjacent the main fluid flow passage.

The main fluid flow passage may be substantially cylindrical and the additional flow passage may be disposed in the plate means substantially radially of the main fluid flow passage.

The control means may ccmprise an obturating device which may be adjustable to control the passage of fluid along the additional fluid flow passage.

The obturating means may comprise a needle valve projecting into the additional fluid flow passage intermediate the length thereof.

The needle valve may be adjustable by a spring biassed screw thread whereby the needle valve may be mounted in a bore in the plate means.

The obturating device may comprise a pressure operated valve means.

The pressure operated valve means may comprise a tube which may define the additional fluid flow passage and which may mount under bias a ball valve.

The ball valve may be mounted under bias of a spring.

The apparatus may include a plurality of separate devices adapted for insertion in the main fluid flow passage whereby the apparatus is adaptable for accommodating different fluid flow requirements.

This provides a particularly simple yet efficient way of servicing several different sizedcarburettors, for example.

According to a third aspect of the invention there is provided an induction system of an internal combustion engine comprising primary fuel vaporisation means, and an inlet manifold for receiving vaporised fuel, and apparatus as hereinbefore defined mounted therebetween.

The primary fuel vaporisation means may comprise a carburettor, and the device may extend into the outlet passage fram the carburettor.

This provides for relatively efficient vaporisation of fuel.

A device and apparatus embodying the invention are hereinafter described, by way of example, with reference to the accompanying drawings : - Fig.l is a plan of apparatus for providing a fluid flow according to the invention; Fig.2 is a section on line 2-2 in Fig.l; Fig.3 is a side elevation of a device, or venturi insert, for insertion in the apparatus of Fig. 1; Fig.4 is a part section on line BB through the insert of Fig.3; Fig.5 is a side elevational view of the apparatus of Fig.l; Fig.6 is a plan view of an alternative embodiment of apparatus according to the invention; and Fig.7 is a section on line A-A' of Fig.6.

Referring to the drawings, particularly Figs. 3-4, there is shown a device or venturi insert 14 for insertion into apparatus for providing a fluid flow, comprising a body 21 having a through passage defining a venturi having a venturi throat between parts 26 and 27, and a plurality of spaced apart bores extending into the through passage.

An apparatus or venturi assembly comprises a main body plate 11 having fixing holes 12, one on either side of a main fluid flow passage or bore 13 in which fits or is located the venturi insert 14 which is formed with an external flange or lip 15. The main bore 13 has an enlarged end portion to form a recess 16 to receive the lip 15. The lip 15 forms means for locating the insert in the bore 13.

The device 14, shown particularly in Figs. 3 & 4, comprises a cylindrical body 21 having an external annular groove 23 in which the plurality of spaced apart bores 24 are situated radially of the through passage and equally spaced around the device 14 and leading fran the annular groove 23 to the internal bore of the device 14.

As can be seen in Fig.5, the through passage or internal bore of the cylindrical body 21 of the insert 14 has an upper restricted cylindrical portion 26 into which the bores 24 extend and a tapered or conical portion 27 diverging towards the edge of the device 14 opposite the flange or lip 15. When fluid flows through the device or insert 14, the reduction in the bore 26, 27 caused by the tapered portion 27 causes an increase in velocity and decrease in pressure which draws additional fluid through the bores 24 into the fluid flow.

Flow of additional fluid into the device or insert 14 is controlled by obturating means in the form of a needle valve, shown in Figs. 1 & 2. A radial passage 31 extends fram a connector 32 for a flexible tube (not shown) which is screwed into a fixing hole 33 at the end of the radial passage 31. At an intermediate point 38 along the passage 31, a needle valve 34 is mounted in order to control the cross-section of the passage 31 at the point 38, the adjustment being made by rotating a screw head 35 of the valve 34 under the control of biassing means in the form of a spring 36.

In an alternative embedizent (not shown), the bores 24 for the additional fluid are located downstream of the constricted portion 26 in a portion of the venturi having a greater diameter than that of the constricted portion. After passing through the constricted portion, the main flow is still at increased velocity and decreased pressure by the time it reaches the bores 24 and so still draws in additional fluid.

The apparatus or venturi assembly shown in the drawings can be used to adapt an existing internal combustion engine by fitting the main body between primary fuel vaporisation means such as a carburettor, and a main inlet manifold. It is intended that the body plate 11 should be mounted between the carburettor and the main inlet manifold of an internal combustion engine, all being fixed together by bolts passing through the fixing holes 12, the bore 13 being of the appropriate diameter to coincide with the outlet of the carburettor, with the tapered portion 27 extending into the outlet passage of the carburettor. The bolts clamp the main body plate to the inlet manifold, so that the device 14 is clamped in position by the inlet manifold.It would however be possible to adapt the device 14 and the plate 11 so that the device extends into the manifold rather than into the carburettor, the insert then being clamped by the carburettor. The apparatus may be used with a fuel injector instead of a carburettor.

If different sizes of carburettor outlets (or inlet manifold inlets) are encountered, separate devices of differing characteristics such as size 14 can be used with the same main body plate 11. When the engine is running, the needle valve 34 is adjusted to control the flow of additional fluid into the venturi device or insert 14 until the desired performance of the engine is achieved. If different operating parameters are to be arranged, a device 14 selected fram the separate devices for for example with a different size shape of bore constriction or a different arrangement of bores 24 can be substituted in the main body plate 11.

Referring now to Figs. 6 and 7, there is shown an alternative embodiment having obturating means which replaces the radial passage 31 and needle valve, whilst achieving a similar result.

Adjacent to converging portion are provided bores like bores 24, a tube 111, and adjustable member 112, a female thread threaded on a male thread on tube 111, and which is lockable in position by a lock nut 113. The adjustable member 112 has a partially closed end in which a ball 115 seats on surfaces of an aperture to form a ball valve, the ball being held in position by biassing means such as a spring 117,may be connected to an existing air filter on the engine by means of a pipe or tube. There is a clear passageway from the valve seat 115 through the tubes 111 ,131 to the air intake into aperture 102.

In addition, when the engine is operating under conditions of high inlet manifold vacuum, such as when the throttle valve is closed or almost closed during phases of de-acceleration or idling, atmospheric pressure acting on the exposed surface of ball 115 causes it to trove away fran aperture 116 against the force of spring 117 and so admit additional air through tubes 111 and 131 and bores 110. This air then mixes with fuel vapour from the carburettor. Thus the effective air to fuel ratio of the ccmbustion mixture is increased during the idling and de-acceleration phases which is beneficial in the reduction of exhaust pollutants fram the engine. The degree of opening of the ball valve and the inlet vacuum, at which the ball valve opens may be adjusted by the movement of adjustable member 112 to vary the force exerted on ball 115 by spring 117.

It will be understood from the foregoing that a device and apparatus as hereinbefore described and embodying the invention provides an assembly in which a venturi construction is formed in a component (the device 14) separate fram the main body plate 11, and a venturi in which the additional fluid is supplied to the main fluid flow at a plurality of spaced locations. This provides for thorough, uniform mixing and vaporisation of a vaporisable liquid fuel prior to canbustion.

Claims

1. A device for insertion into apparatus for providing a fluid flow, comprising a body having a through passage defining a venturi, and a plurality of spaced apart bores extending into the through passage.

2. A device according to Claim 1, the body being cylindrical.

3. A device according to Claim 2, the bores being spaced circumferentially around the body.

4. A device according to Claim 3, the body having an external annular groove, the bores being in the groove.

5. A device according to any preceding claim, the bores being adjacent a throat of the venturi.

6. A device according to any preceding claim, the body having means to locate the device on insertion into apparatus providing fluid flow.

7. A device according to Claim 6, the locating means comprising an external flange or lip projecting from the body.

8. A device according to Claim 7, the lip or flange being at one end of the body.

9. A device according to any preceding claim, the venturi including a portion of greater diameter than the throat thereof.

10. A device according to Claim 9, the bores opening into said portion.

11. Apparatus for providing a fluid flow, comprising means defining a main fluid flow passage and an additional fluid flow passage, means to control flow of fluid in the additional fluid flow passage, and a device adapted for insertion in the main fluid flow passage and having a through passage defining a venturi and a plurality of spaced apart bores extending into the through passage, the arrangement being such that the through passage comprises the main fluid flow passage when the device is inserted in the means.

12. Apparatus according to Claim 11, the means comprising a plate means adapted for mounting on a fluid flow provider.

13. Apparatus according to Claim 12, the plate means being adapted by through holes for receiving securing means.

14. Apparatus according to Claim 12 or Claim 13, the main fluid passage having locating means for the device.

15. Apparatus according to Claim 14, the locating means comprising a recess in the plate adjacent the main fluid flow passage.

16. Apparatus according to Claim 15, the main fluid flow passage being substantially cylindrical and the additional flow passage being disposed in the plate means substantially radially of the main fluid flow passage.

17. Apparatus according to Claim 16, the control means comprising an obturating device which is adjustable to control the passage of fluid along the additional fluid flow passage.

18. Apparatus according to Claim 17, the obturating means comprising a needle valve projecting into the additional fluid flow passage intermediate the length thereof.

19 Apparatus according to Claim 18, the needle valve being adjustable by a spring biassed screw thread whereby the needle valve is mounted in a bore in the plate means.

20. Apparatus according to Claim 17, the obturating device comprising a pressure operated valve means.

21. Apparatus according to Claim 20, the pressure operated valve means ccmprising a tube defining the additional fluid flow passage and mounting under bias a ball valve.

22. Apparatus according to Claim 21, the ball valve being mounted under bias of a spring.

23. Apparatus according to any of Claims 11 to 22, including a plurality of separate devices adapted for insertion in the main fluid flow passage whereby the apparatus is adaptable for acccmcdating different fluid flow requirements.

24. An induction system of an internal combustion engine, comprising primary fuel vaporisation means, and an inlet manifold for receiving vaporised fuel, and apparatus according to any of Claims 11 to 23 mounted therebetween.

25. An indication system according to Claim 24, the primary fuel vaporisation means comprising a carburettor.

26. An induction system according to Claim 25, the device extending into the outlet pasage from the carburettor.

27. An induction system according to Claim 25, the device extending into the inlet passage of the inlet manifold.

28. A device for insertion into apparatus for providing fluid flow, substantially as hereinbefore described with reference to the accompanying drawings.

29. Apparatus for providing a fluid flow, substantially as hereinbefore described with reference to the accompanying drawings.

30. An induction system for an internal combustion engine, substantially as hereinbefore described with reference to the accompanying drawings.