GB1569655A

GB1569655A - Control devices for supplying gaseous fuel to a carburettor

Info

Publication number: GB1569655A
Application number: GB26225/77A
Authority: GB
Original assignee: ZALOKAR Z
Current assignee: ZALOKAR Z
Priority date: 1976-06-24
Filing date: 1977-06-23
Publication date: 1980-06-18
Also published as: DE2727515A1; LU77596A1; YU154076A; FR2356012A1; NL7706935A; BE855915A

Description

(54) IMPROVEMENTS IN OR RELAMNG TO CONTROL DEVICES FOR SUPPLYING GASEOUS FUEL TO A CARBURETTOR (71) We, MIRKO LINDTNER, of Celovska 44, 61000 Ljubljana; PETERCUSIK, of Kristanova 26, 68000 Novo Mesto; FRANC KORI > IK, of Skofijica 84, 61291 Skofljica; and ZARKO ZALOKAR, of Periceva 46, 6100 Ljubljana, all in Yugoslavia, and all Yugoslavian Citizens, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to control devices for supplying gaseous fuel to a carburettor.

A known fuel control arrangement for use in internal-combustion engines operating with gaseous fuel, comprises a control device having a casing equipped with a diaphragm biased by a spring and having a shaft fixed at its centre, which shaft engages one end of a control lever, whose other end, near pivot of the lever, engages a valve arranged at the bottom of the casing. The lever is biased by a regulating spring, one end of which rests upon a plate supported by an adjusting or regulating screw which is pivotally fastened to the bottom of said casing. The other end of said spring presses via a spring-plate against said control lever. Said valve is connected via a pipe connection located on one side of the casing, an evaporator, a further valve and a pressure reducing valve to a tank containing liquefied gaseous fuel.On the other side of the casing is a pipe connection for the gas supply pipe leading to the carburettor.

This known arrangement has the following drawback. Safety of operation is not sufficient because if the remote-controlled gas valve for supplying gas to said control device does not close, (i.e. if the ignition system is switched on,) and the engine out of operation, the gas can stream into the carburettor and thus escape into the open air.

An object of the invention is to provide a control device which obviates the abovementioned drawback.

According to the invention, there is provided a control device for supplying gaseous fuel to a carburettor of an internal combustion engine, the device comprising: a main chamber having an inlet for receiving gaseous fuel and an outlet for delivering gaseous fuel; regulating means for maintaining the pressure of gaseous fuel at a suS stantially constant value in said chamber; and a safety closing device arranged to prevent ingress of gaseous fuel via said inlet when the control device is not in use.

Preferably, said regulating means comprises: a valve means arranged in said inlet and movable to vary the flow of gaseous fuel through said inlet; a diaphragm biased by resilient means and disposed in a wall of said chamber and movable in response to changes in pressure within the chamber; and a link member connected to the diaphragm and to the valve means so that said movement of the diaphragm is transmitted to the valve means which is thereby so moved, in use of the device, as to tend to maintain the pressure within the chamber at said constant value.

Preferably, said link member has two arms and is generally L-shaped, one end of the member being pivotally mounted in the chamber, and the other end being connected to the diaphragm, the member being connected to said valve means at a point intermediate said one end and the apex of said L-shaped member.

Preferably, said link member is connected to the diaphragm via a shaft extending substantially from the centre of the diaphragm.

Preferably, said resilient means is constituted by a spring acting between a sleeve and the centre of the diaphragm, the sleeve being threaded so that its position relative to said chamber is adjustable by rotation thereby to provide for fine setting of said constant value.

Preferably, there is provided a control means arable to effect an increase in said pressure for temporary increased power output of said engine.

Preferably, said control means is operable to vary the biasing force on said diaphragm.

Preferably, said spring acts against a plate provided within said sleeve which plate forms part of said control means and is slidable within said sleeve against the action of a return spring.

Expediently, there is provided a plate spring acting between said link member and a pivotably mounted L-shaped lever whose position is adjustable by turning of a setting screw to provide rough regulation of said control device.

In a preferred embodiment of the invention, there is provided a safety closing device arranged to prevent ingress of gaseous fuel via said inlet when the device is not in use.

Preferably, said closing device comprises a resiliently biased member acting on said link member in a sense such as to close said valve means.

Preferably, said closing device comprises: a second chamber within said main chamber and sealed therefrom, one wall of the second chamber being constituted by a further diaphragm on which is mounted said member acting on the link member; a spring within the second chamber acting on said diaphragm; and an inlet to said second chamber for connection to a zone of said carburettor which is at relatively low pressure during use, so that the pressure within said second chamber can be thereby reduced to arrest closing action of the closing device.

According to a further aspect of the invention, there is provided a fuel control arrangement for an internal combustion engine and comprising: a control device according to said one aspect; and a carburettor connected to said outlet to receive gaseous fuel from said control device, the inlet of the control device being connected via a pressure reducer to an evaporator for evaporating liquefied gaseous fuel.

Preferably, said evaporator is connected to a high-pressure tank via a valve assembly which also contains said pressure reducer.

Preferably, said control means of the control device is connected to a butterfly valve of the carburettor for movement therewith.

Preferably, said evaporator comprises a tube assembly having two concentric tubes joined together at one end of the assembly, there being two partition walls extending radially of the tubes at respective diametrally opposed positions, extending longitudinally of the tubes parallel to their common axis and extending between the tubes, said walls not extending to said joined end so that two chambers of semi-annular cross-section are formed, the chambers being linked at said joined end, there being respective inlet and outlet ports opening into respective ones of the chambers at the other end of said assembly, and there being a jacket for liquid heating medium surrounding said tube assembly and having inlet and outlet ports for said medium one port being laterally of said axis, and the other being on said axis in the region of said other end, so that said medium can pass within and without said assembly whilst being sealed from the space between said tubes.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 shows a fuel control arrangement including a control device according to the invention; Figure 2 shows a remote-controlled valve provided with a pressure reducer; Figure 3a shows an evaporator for liquefied gas in lateral section; Figure 3b shows a transverse section of the evaporator of Figure 3a; and Figure 4 shows a control device according to the invention.

Figure 1 shows a fuel control arrangement for an internal combustion engine running on gaseous fuel stored in liquefied state in a high-pressure tank. The arrangement includes a tank 1 for liquefied gaseous fuel (propane or butane) on which is mounted a delivery valve-assembly 2 comprising a feed valve and a safety valve. Said delivery valve-assembly 2 is connected via a highpressure pipe 3 to a remote-controlled valve assembly 4 provided with a pressure reducer.

Valve assembly 4 is connected by means of pipes 5 and 6 to an evaporator 7 or 8, which can be such as to operate on hot water or on exhaust gases. Gaseous fuel from the evaporator passes through pipe 6 to the pressure reducer of assembly 4 and thence via pipe 9 to a control device 10. Reinforced rubber tube 11 connects device 10 to a carburetttor 13. The device 10 is connected by means of a pushing Bowden cable 15 to a lever of a butterfly valve 14 of a carburettor 13 actuated by the accelerator control of the engine. From the low pressure chamber of carburettor 13 pipe 16 leads into a safety self-closing device 47 located in device 10 (see Figure 4). The carburettor 13 is for petrol operation of the engine connected by a corresponding pipe to a remote-controlled valve 20 for controlling the supply of petrol.

Valve 20 is connected by means of electrical cable 19 to an electrical switch 17, which is connected by cable 18 to remote-controlled valve assembly 4.

The control device 10 shown in Figure 4 has a housing 40 enclosing a chamber provided at one end with an inlet 41 for connec tion to supply pipe 9 (see Figure 1). - In- this inlet is arranged a valve 42. At the side of housing 40 an L-shaped link member 43 is pivotally mounted on pivot 44. Between pivot 44 and its apex, member 43 is connected to valve 42. At its end remote from pivot 44, member 43- is connected to a shaft 57 which in turn is fixed to the centre of an diaphragm 51. The diaphragm is urged inwardly of the housing by a spring 53 which presses against a plate 54, this plate cooperating with a pushing Bowden cable 15 (Figure 1). Said plate 54 is arranged in a threaded sleeve 55 which is screwed into cover 52 of said device and may be rotated to provide fine regulation by varying -the tension of spring 53.Plate 54 is maintained in position within sleeve 55 by a return spring 56. At the other side of housing 40 is provided the safety self-closing device 47 consisting of diaphragm 48 fixed by means of clamp ring 49 to a corresponding housing, which is by means of a pipe 16 connected to an inlet 50 (Figure 4) in communication with said low-pressure chamber of carburettor 13 (Figure 1). Upon said diaphragm 48 is mounted a shaft 45. Between the inner side of said diaphragm 48 and said housing is arranged a spring 46. Shaft 45 presses against L-shaped link member 43 which is biased by a plate spring 58 which presses against an L-shaped adjusting lever 59 pivotally fixed on a pivot 60 and provided with a screw 61 for rough regulation of the control device.Housing 40 also has an outlet 62 for pipe 11 intended for the delivery of gas to the carburettor through corresponding connection 12 at the carburettor.

Evaporator 7 of Figure 1 is shown in detail in Figure 3a. It consists of an end plate 28 supporting an inner tube 29, coaxially surrounded by a middle tube 30, around which is coaxially arranged an outer tube 31 closed at its end remote from plate 28 and having at the other end a lateral side pipe connection 35 for discharging hot water. Said outer tube 31 is welded to plate 28. Round the extension of the axis of symmetry of said inner tube 29, plate 28 is provided with a pipe connection 32 for receiving hot water. On sides of plate 28 there is an inlet 36 for liquefied gas and an outlet 39 for gaseous fuel. Inlet 36 and outlet 39 are in communication with the annular space between middle tube 30 and inner tube 29.As shown more clearly in Figure 3b, between said middle tube and said inner tube 29, i.e. in said annular space, are arranged two radially extending partition walls 38 extending along said tubes 29 and 30 and ending before the lower ends in Figure 3a of said tubes 29 and 30. At the lower ends, tubes 29 and 30 are divergently and conically shaped respectively and joined to each other. By such arrangement, said pipe connection -32 can supply - hot water through inner channel: 33 and communicates with pipe connection 35 for the outlet of hot water. Inlet 36 for the intake of liquefied gas is -similarly in communicatio:l with pipe connection 39 for the outlet of evaporated gaseous fuel.

Figure 2 shows the remote-controlled valve assembly 4 of Figure 1 in greater detail. It- comprises a housing 22 provided with pipe connection 23 for the connection to tank 1 for liquefied gas, a channel 24 communicating with a remote-controlled valve 21, a pipe connection 25 for the supply of liquefied gas to evaporator 7, a pipe connection 26 for receiving gaseous fuel from evaporator, and a pipe connection 27 for the communication with control device 10, (see Figure 1).

The fuel control arrangement operates as follows: Liquefied fuel from tank 1 flows through delivery valve-assembly 2 and high-pressure pipe 3, and enters valve-assembly 4 through pipe connection 23. The fuel then flows through channel 24 (Figure 2) to remote controlled valve 21. When said valve 21 is open, liquefied gas flows to pipe connection 25 and proceeds through pipe 5 to evapora- tor 7. It enters inlet pipe connection 36, flows through channel 37 and is heated and evaporated. Then in gaseous form it flows through pipe connection 39 and through pipe 6 to pipe connection 26 of valveassembly 4 provided with a pressure reducer.

In said pressure reducer, built into said valve assembly reduction of gas pressure occurs in the usual manner. The gas then flows through pipe connection 27 and pipe 9 to control device 10 and through its inlet 41 to valve 42, which is pressed shut by Shaped member 43. When the engine is not running, spring 46 acts upon diaphragm 48 and shaft 45 fixed to said diaphragm and biases member 43 with such force the valve 42 remains closed irrespective of the operation of diaphragm 51 and Bowden cable 15, and irrespective of the influence of spring 53 and plate spring 58.When the engine begins to operate, the reduced pressure in the carburettor causes lowered pressure also in the chamber safety self-closing device 47, while pressure acts upon the other side of diaphragm 48 and compresses spring 46 so that shaft 45 ceases to press upon member 43. Thus the safety self-closing device is rendered inoperative and the control device operates normally. Thus the control device operates on the basis of reduced pressure in the carburettor and on the basis of gas pressure established inside-housing 40 which pressure acts on diaphragm 51 to control the delivery of gas through pipe connection 62 and reinforced rubber pipe 11 to carburettor 13. As the pressure on diaphragm 51 drops, said diaphragm opens valve 42 by means of shaft 57 and member 43, thus allowing more gas into chamber 40.Thus the pressure in housing 40 is maintained at a substantially constant predetermined value. By means of a screw 61 rough regulation or setting of gas pressure is achieved, while fine regulation is achieved by means of rotation of threaded sleeve 55. Regulation or setting is performed in such manner as to obtain optimum gas pressure for economical running. When it is necessary to increase the engine power to its maximum the movement of the butterfly valve of carburettor 13 activates Bowden cable 15, the end thereof pushing upon plate 54, which in its turn compresses spring 53 and, consequently, increases the force on the outer side of main diaphragm 51 thereby causing greater delivery of gas to the engine.

It will also be apparent that the Bowden cable 15 is also needed during starting of the engine. It helps to release the self-closing device during starting. Without this release, ignition of the engine is rendered difficult.

WHAT WE CLAIM IS:- 1. A control device for supplying gaseous fuel to a carburettor of an internal combustion engine, the device comprising: a main chamber having an inlet for receiving gaseous fuel and an outlet for delivering gaseous fuel; regulating means for maintaining the pressure of gaseous fuel at a substantial7y constant value in said chamber; and a safety closing device arranged to prevent ingress of gaseous fuel via said inlet when the control device is not in use.

2. A control device according to Claim 1 wherein said regulating means comprises: a valve means arranged in said inlet and movable to vary the flow of gaseous fuel through said inlet; a diaphragm biased by resilient means and disposed in a wall of said chamber and movable in response to changes in pressure within the chamber; and a link member connected to the diaphragm and to The valve means so that said movement of the diaphragm is transmitted to the valve means which is thereby so moved, in use of the device, as to tend to maintain the pressure within the chamber at said constant value.

3. A control device according to Claim 2 wherein said link member has two arms and is generally L-shaped, one end of the member being pivotally mounted in the chamber. and the other end being connected to the diaphragm, the member being connected to said valve means at a point intermediate said one end and the apex of said L-shaped member.

4. A control device according to Claim 3 wherein said link member is connected to the diaphragm via a shaft extending substantially from the centre of the diaphragm.

5. A control device according to any one of Claims 2 to 4 wherein said resilient means is constituted by a spring acting between a sleeve and the centre of the diaphragm, the sleeve being threaded so that its position relative to said chamber is adjustable by rotation thereby to provide for fine setting of said constant value.

6. A control device according to any one of claims 1 to 5 wherein there is provided a control means operable to effect an increase in said pressure for temporary increased power output of said engine.

7. A control device according to claim 6 wherein said control means is operable to vary the biassing force on said diaphragm.

8. A control device according to Claim 7 when dependent on Claim 5 wherein said spring acts against a plate provided within said sleeve which plate forms part of said control means and is slidable within said sleeve against the action of a return spring.

9. A control device according to any one of Claims 2 to 8 wherein there is provided a plate spring acting between said link member and a pivotally mounted L-shaped lever whose position is adjustable by turning of a setting screw to provide rough regulation of said control device.

10. A control device according to any one of Claims 1 to 9 wherein said dosing device comprises a resiliently biased member acting on said link member in a sense such as to close said valve means.

11. A control device according to Claim 10 wherein said closing device comprises: a second chamber within said main chamber and sealed therefrom, one wall of the second chamber being constituted by a further diaphragm on which is mounted said member acting on the link member; a spring within the second chamber acting on said diaphragm; and an inlet to said second chamber for connection to a low pressure zone of said carburettor so that the pressure within said second chamber can be thereby reduced to arrest closing action of the dos- ing device.

12. A control device substantially as hereinbefore described with reference of Figure 4 of the accompanying drawings.

13. A fuel control arrangement for an internal combustion engine and comprising: a control device according to any one of the preceding Claims; and a carburettor connected to said outlet to receive gaseous fuel from said control device, the inlet of the control device being connected via a pressure reducer to an evaporator for evaporating liquefied gaseous fuel.

14. An arrangement according to Claim 13 wherein said evaporator is connected to a high-pressure tank via a valve-assembly which also contains said pressure reducer.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. 13. As the pressure on diaphragm 51 drops, said diaphragm opens valve 42 by means of shaft 57 and member 43, thus allowing more gas into chamber 40. Thus the pressure in housing 40 is maintained at a substantially constant predetermined value. By means of a screw 61 rough regulation or setting of gas pressure is achieved, while fine regulation is achieved by means of rotation of threaded sleeve 55. Regulation or setting is performed in such manner as to obtain optimum gas pressure for economical running.When it is necessary to increase the engine power to its maximum the movement of the butterfly valve of carburettor 13 activates Bowden cable 15, the end thereof pushing upon plate 54, which in its turn compresses spring 53 and, consequently, increases the force on the outer side of main diaphragm 51 thereby causing greater delivery of gas to the engine. It will also be apparent that the Bowden cable 15 is also needed during starting of the engine. It helps to release the self-closing device during starting. Without this release, ignition of the engine is rendered difficult. WHAT WE CLAIM IS:-

1. A control device for supplying gaseous fuel to a carburettor of an internal combustion engine, the device comprising: a main chamber having an inlet for receiving gaseous fuel and an outlet for delivering gaseous fuel; regulating means for maintaining the pressure of gaseous fuel at a substantial7y constant value in said chamber; and a safety closing device arranged to prevent ingress of gaseous fuel via said inlet when the control device is not in use.

15. An arrangement according to Claim

13 or 14 wherein said control means of the control device is connected to a butterfly valve of the carburettor for movement therewith.

16. An arrangement according to any one of Claims 13 to 15 wherein said evaporator comprises a tube assembly having two concentric tubes joined together at one end of the assembly, there being two partition walls extending radially of the tubes at respective diametrally opposed tposi- tions, extending longitudinally of the tubes parallel to their common axis and extending between the tubes, said walls not extending to said joined end so that two chambers of semi-annular cross-section are formed, the chambers being linked at said joined end, there being respective inlet and outlet ports opening into respective ones of the chambers at the other end of said assembly, and there being a jacket for liquid heating medium surrounding said tube assembly and having inlet and outlet ports for said medium, one port being laterally of said axis, and the other being on said axis in the region of said other end, so that said medium can pass within and without said assembly whilst being sealed from the space between said tubes.

17. An arrangement according to Claim 16, the evaporator being substantially as hereinbefore described with reference to Figure 3 of the accompanying drawings.

18. An arrangement according to Claim 14 or any one of Claims 15 to 17 as dependent on Claim 14, wherein said valve assembly is substantially as hereinbefore described with reference to Figure 2 of the accompanying drawings.

19. A fuel control arrangement including a control device according to Claim 1 and being substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.

20. An internal combustion engine having a fuel control arrangement according to any one of Claims 13 to 19.