GB2226119A

GB2226119A - Combined liquefied gas evaporator-gas pressure regulator

Info

Publication number: GB2226119A
Application number: GB8928396A
Authority: GB
Inventors: Angel Yordanov Dimitrov; Dyanko Baychev Dyankov; Slavcho Syoyanov Zechev
Original assignee: BURGASAUTOTRANSPORT FA
Current assignee: BURGASAUTOTRANSPORT FA
Priority date: 1988-12-15
Filing date: 1989-12-15
Publication date: 1990-06-20
Also published as: DE3941341A1; FR2640694B3; FR2640694A1; BG47752A1; HUT52211A; DD301919A9; GB8928396D0

Abstract

A combined liquefied gas evaporator-gas pressure regulator comprises a housing (1) having inlet (2) and outlet (15) fuel conduits connected respectively to high pressure (A) and low pressure (B) reduction chambers in the housing with a first spring loaded valve (10, 11, 12) being provided between the two reduction chambers and with the two reduction chambers additionally being communicable through a third chamber (C) for use during idling of an internal combustion engine to which connection of the outlet fuel conduit is made, in use, which third chamber includes control means (18, 19) for closing off entry thereinto of gas from the high pressure reduction chamber which is itself provided with preheating means for liquefied gas supplied as fuel, in use, to the inlet fuel conduit (2) to promote evaporation of the liquefied gas in the high pressure reduction chamber, a second spring loaded valve (3, 4, 5) communicating the high pressure reduction chamber (A) with the inlet fuel conduit (2) in which regulator, each of the high pressure and low pressure reduction chambers and the third chamber is spanned by a diaphragm, with the diaphragms (6, 13) in the high pressure and low pressure reduction chambers being positioned to actuate operation of said first spring loaded valve and the control means (18, 19) for closing off communication between the high pressure reduction chamber (A) and the third chamber (C) a control (22) screw disposed below the diaphragm (18) of the third chamber and drivable by spring means (19) against the diaphragm of the third chamber. <IMAGE>

Description

1 G, - - j_ El r -1 COMBINED LIQUEFIED GAS EVAPORATOR-GAS PRESSURE

REGULATOR This invention relates to a combined liquefied gas evaporator-gas pressure regulator which can be used in mechanical engineering, particularly in internal combustion engines operating with liquified gas fuel.

A known combined liquefied gas evaporator-gas pressure regulator consists of a housing having inlet and outlet fuel conduits connected respectively to gas pressure reduction chambers for low and for high pressure operation respectively. The chambers incorporate working diaphragms and are interconnected by a conduit in which there is mounted a valve actuated by the working diaphragm of the low pressure chamber by means of a rocker arm. Between the inlet fuel conduit and the high pressure reduction chamber there is also mounted a valve which is actuated by an associated working diaphragm by means of a rocker arm. There is additionally provided a third fuel chamber whose utilisation is effected during idling of the engine.

This third fuel chamber is provided with a working diaphragm and connected via a control screw to the outlet fuel conduit. The housing for the overall device additionally comprises an independent preheating chamber in which water circulates via inlet and outlet pipes and which is branched off from the cooling system of the engine. A starting electromagnet is mounted in association with the low pressure reduction chamber.

Such a combined liquefied gas evaporator-gas pressure regulator has a number of disadvantages including unreliable operation because of the rapid failure of the working diaphragms as a result of the wide temperature differences under different operating conditions. The device also contains a large number of componentsg thereby rendering difficult maintenance and repair thereof. The connecting passages within the C device tend to have a small throughput capacity. Should there be a rupture of the working diaphragm of the high pressure reaction chamber there is the possibility of gas leakage to the atmosphere. Gas leakage may also take place through the control screw for idling revolutions. It is impossible to guarantee accurate metering of vaporised.liquid gas fuel under different operating cofiditions because of the possibility of maintaining constant thermal conditions in the combined liquefied gas evaporator-gas pressure regulator.

According to the present invention, there is provided a combined liquefied gas evaporator-gas pressure regulator comprising a housing having inlet and outlet fuel conduits connected respectively to high pressure and low pressure reduction chambers in the housing, with a first spring loaded valve being provided between the two reduction chambers and with the two reduction chambers additionally being communicable through a third chamber for use during idling of an internal combustion engine to which connection of the outlet fuel conduit is made, in use, which third chamber includes control means for closing off entry thereinto of gas from the high pressure reduction chamber which is itself provided with preheating means for liquefied gas supplied as fuel, in use, to the inlet fuel conduit to promote evaporation of the liquefied gas in the high pressure reduction chamber, a second spring loaded valve communicating the high pressure reduction chamber with the inlet fuel conduit, in which regulator, each of the high pressure and low pressure reduction chambers and the third chamber is spanned by a diaphragm, with the diaphragms in the high pressure and low pressure reduction chambers being positioned to actuate operation of said first spring loaded valves and the control means for closing off communication between the high pressure reduction chamber and the third chamber comprising a control screw disposed below the diaphragm of the third chamber and drivable by spring means against the diaphragm of the third chamber.

The present invention enables there to be achieved reliable operation of a combined liquefied gas evaporator-gas pressure regulator as a result of the elimination of narrow connecting fuel conduits and rocker arms, thereby facilitating maintenance and repair. 0 The various conduits are conveniently milled in a monlithic housing block.

According to a preferred embodiment of the invention, a space below the diaphragm of the high pressure reduction chamber communicates via a conduit with a space below the diaphragm of the low pressure reduction chamber. This enables the possibility of gas leakage to the atmosphere in the event of rupture of the diaphragm of the high pressure reduction chamber to be avoided. Moreover, the device of the invention enables gas leakage to the atmosphere to be avoided in the event of depressurization of the control means for the diaphragm of the third chamber.

Finally, according to a further embodiment of the invention, an electromagnetic valve in duct means for supply of preheating liquid to the preheating chamber, in electrical communication with a relay and a temperature detector associated with the outlet fuel conduit. This arrangement enables a constant temperature state of the components of the combined liquefied gas evaporator-gas pressure regulator to be achieved. This is favourable for achieving a longer operating life of all rubber components, including working diaphragms and seals, as well as a better mixing of fluids within the device.

For a better understanding of the invention and to _1 k show how the same can be carried into effect, reference will now be made by way of example only to the accompanying drawing which is a cross-section through a preferred form of device embodying the invention, the section being taken axially with respect to the gas pressure reduction chambers.

The combined liquefied gas evaporator-gas pressure regulator shown in the drawing comprises two gas pressure reduction chambers, a high pressure reduction chamber A and a low pressure reduction chamber B as well as a fuel chamber C which is operative during idling of the engine. These chambers are integrated within a common housing 1 in which there is formed a horizontal fuel conduit 2 for introduction of liquified fuel gas to the chamber A in the inlet to which there is mounted a valve seat 3 having a central opening in which a closure member 4 is seated, which closure member may be pressed against the seat 3 by a spring 5.

The reduction chamber A has the following characteristics: a diaphragm 6 spans the chamber A, being clamped against the housing 1 by a cover 7 in which is mounted a spring 8 which is positioned to act on the closure member 4 via the diaphragm 6. A finned plate 9 is mounted in the reduction chamber A to assist in heat distribution for evaporating the liquefied gas.

Mounted in the housing 1 between reduction chambers A and B is a valve seat 10 having a central opening in which a closure member 11 is seated. The closure member is pressed by a spring 12 against the seat 10.

The reduction chamber B has the following characteristics: it is closed by a diaphragm 13 which is clamped between the housing 1 and a cover 14 and the space above the diaphragm is connected via an opening in cover 14 with the atmosphere. The space below the diaphragm communicates via an outlet fuel conduit 15 with the engine carburetor. The fuel chamber C for use C, during idling of the engine is Positioned near the valve seat 10 and has a cover 16 which communicates via an opening 17 with chamber B. The cover 16 clamps a diaphragm 18 against the housing 1 and beneath the former there is disposed a spring 19 which acts on the diaphragm 18 for driving fuel through an opening 20 which is formed in the cover 16 and which communicates via a conduit 21 with the reduction chamber A. in the wall of the housing 1 below the diaphragm 18 there is mounted a control screw 22. The space below the diaphragm 18 has an outlet passage 23 for connection to the input manifold of an internal combustion engine. Also formed within the housing 1 and continuing into the cover 7 is a conduit 24 which connects the space below the diaphragm 6 of chamber A to the space below the diaphragm of chamber B. Between the housing 1 and the cover 7. there is formed around the reduction chamber A a pre-heating chamber D which is connected to an inlet pipe connection 25 and an outlet pipe connection 26 to the cooling system of the engine. Within the inlet pipe connection 25 and adjacent housing 1 there is mounted an electromagnetic valve 27 which is included in a common electric circuit with relay 28 and temperature.detector 29 which is mounted to the outlet fuel conduit 15.

Operation of the combined liquefied gas evaporator-gas pressure regulator shown in the drawing takes place as follows:

When an internal combustion engine with which the combined liquefied gas evaporator-gas pressure regulator is to be used is not in operation. that is there is no supply of liquefied gas to the fuel conduit 2. the spring 8 presses the diaphragm 6 in the direction of the valve seat 3 so that the closure member 4 is not pressed against the valve seat and the reduction chamber A is in communication with the t) conduit 2. At this time, the closure member 11 is pressed under the action of spring 12 against the valve seat 10. The diaphragm 13 of reduction chamber B is in a neutral position since the pressure on both sides thereof is equal to the prevailing atmospheric pressure. The diaphragm 18 in chamber C is subject to the action of spring 19 so as to block the access to the fuel delivery hole 20 leading to the connecting conduit 21. The electromagnetic valve 27 is open and allows the flow of preheating liquid towards chamber D.

When liquefied fuel is to be delivered to the combined liquefied gas evaporator-gas pressure regulator, it passes through conduit 2 and through the opening in valve seat 3 to fill the space above the diaphragm 6 of reduction chamber A. As a result of this, the fuel is vaporised and the pressure on the diaphragm 6 is increased. When the force produced by the gas on diaphragm 6 becomes equal to the force exerted by spring 8, the diaphragm 6 is displaced towards the cover 7 and operation of closure member 4 is released. The action of the spring 5 and liquid pressure on the closure member 4 result in closure taking place at the valve seat 3.

When the internal combustion engine is started, a vacuum is produced in the carburetor and this vacuum extends via the outlet fuel conduit 15 to the space below the diaphragm 13 of reduction chamber B. As a result of the difference then produced between the pressures on both sides of diaphragm 13, the latter is displaced towards the opening in valve seat 11 which is opened as the force of the spring 12 is overcome. As a result, gas in reduction chamber A is able to pass into reduction chamber B and, when its pressure has become equal to atmospheric pressures diaphragm 13 returns towards its initial-position adjacent cover 14 and closure member 11 closes valve seat 10 under the action 1 r L of spring 12 and the pressure of gas in reduction chamber A. As a result of the passage of part of the gas from chamber A to chamber B, the pressure in chamber A is reduced and as a result, spring 8 is able to press the diaphragm 6 against the closure member 4 to open up again the opening in valve seat 3 and enable a new quantity of liquefied gas to enter reduction chamber A, evaporate and increase the pressure within it. Under the action of the gas pressure, the diaphragm 6 is again displaced towards the cover 7 while the closure member 4 closes the opening in the valve seat 3. Supply of gas to the internal combustion engine will thus have taken place via reduction chambers A and B. Operation of the idling system in the device according to the invention is as follows:

During idling of the engine, a vacuum is produced below the throttling valve in the carburetor, which vacuum extends via an appropriate conduit and pipe connection 23 to the space below the diaphragm 18. The existence of this vacuum enables the diaphragm 18 to overcome the force of the spring 19 and be displaced towards the control screw 22, thereby opening access to the outlet opening 20. Gas can now pass from reduction chamber A via the connecting conduit 21 and openings 20 and 17 into reduction chamber B whence, via fuel conduit 15, it passes to the carburetor. The quantity of gas delivered is determined by the distance "a " between the control screw 22 and the diaphragm 18.

Evaporation of the liquefied gas in the device of the invention takes place under the effect of the heat of liquid in the cooling system of the internal combustion engine, which circulates through the preheating chamber D formed in the housing 1. To en ure a. constant temperature of gas emerging from the embined liquefied gas evaporator-gas pressure regulator, thereby influencing positively the loading factor of the engine and increasing the service life of the diaphragm and the rubber seals associated with the device, there is provided an automatic regulating system which operates as follows. The thermal detector 29 records the temperature of the gas leaving the combined liquefied gas evaporator-gas pressure regulator and, should there be a variation in temperature, the relay 28 is actuated and switches on or off as required the electromagnetic valve 27 which regulates the access of preheating liquid to the chamber D. The preheating chamber D surrounds only the reduction chamber A since it is there that intensive evaporation of the liquefied fuel gas must take place. The process of evaporation is also intensified by virtue of the presence of the finned evaporating plate 9, which increases the heat exchange area available.

The purpose of conduit 24 used to communicate the underside of diaphragm 6 with reduction chamber B is that in an emergency, such as rupture of diaphragm 6, gas will pass through it, enter conduit 24 and be removed to the interior of reduction chamber B which is connected to the carburetor of an internal combustion engine. In this way, gas leakage into the atmosphere is prevented.

k laims; 1. A combined liquefied gas evaporator-gas pressure regulator comprising a housing having inlet and outlet fuel conduits connected respectively to high pressure and low pressure reduction chambers in the housing, with a first spring loaded valve being provided between the two reduction chambers and with the two reduction chambers additionally being communicable through a third chamber for use during idling of an internal combustion engine to which connection of the outlet fuel conduit is made, in use, which third chamber includes control means for closing off entry thereinto of gas from the high pressure reduction chamber which is itself provided with preheating means for liquefied gas supplied as fuel, in use, to the inlet fuel conduit to promote evaporation of the liquefied gas in the high pressure reduction chamber, a second spring loaded valve communicating the high pressure reduction chamber with the inlet fuel conduit, in which regulator, each of the high pressure and low pressure reduction chambers and the third chamber is spanned by a diaphragm, with the diaphragms in the high pressure and low pressure reduction chambers being positioned to actuate operation of said first spring loaded valves and the control means for closing off communication between the high pressure reduction chamber and the third chamber comprising a control screw disposed below the diaphragm of the third chamber and drivable by spring means against the diaphragm of the third chamber.

2. A combined liquefied gas evaporator-gas pressure regulator according to claim 1. wherein a space below the diaphragm of the high pressure reduction chamber communicates via a conduit with a space below the diaphragm of the low pressure reduction chamber.

3. A combined liquefied gas evaporator-gas pressure regulator as claimed in claim 1 or 2, which additionally comprises an electromagnetic valve in duct means for supply of preheating liquid to the preheating chamber, in electrical communication with a relay and a temperature detector associated with the outlet fuel conduit.

4. A combined liquefied'gas evaporator-gas pressure regulator substantially as hereinbefore described with reference to and as shown in the accompanying drawing.

PuhUsbaiU990aa7hePatent Office,State House, 66171 High Holborn. London WCIR 4TP. Further copiesmaybe obtainedfrom The PatentOffice. Wes Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent, Co.n. 1/87