FR2640694A1 - Evaporator/pressure-reducing device - Google Patents

Abstract

The present invention relates to an evaporator/pressure-reducing device comprising, in a casing 1, an intake pipe 2 and a discharge pipe 15 for the fuel, which are respectively connected to a high-pressure pressure-reducing chamber A, and to a low-pressure pressure-reducing chamber B. A valve 4 is mounted between the said intake pipe 2 and the high-pressure pressure-reducing chamber A, and another valve 11 is mounted between the two pressure-reducing chambers A, B to which chambers is connected a third chamber C for idling of the engine, provided with an adjustment screw 22. In the three chambers are mounted diaphragms 6, 13, 18 and a chamber D for a preheat liquid is formed around the high-pressure pressure-reducing chamber A. The valves 4, 11 are actuated directly by the respective diaphragms 6, 13 and the adjusting screw 22, associated with a spring 19, is mounted above the diaphragm 18 of the chamber C for idling of the engine, the spaces respectively formed below the diaphragms 6, 13 of the two pressure-reducing chambers being moreover connected together. Use in gas engines.

Description

The present invention relates to an evaporator-

  regulator which can be used in the technological field of engines, and in particular in internal combustion engines operating using a gaseous fuel. There is an evaporator-expansion valve which consists of a casing comprising an inlet pipe and a fuel outlet pipe, respectively connected to two expansion chambers, one at high pressure and the other at low pressure, these two chambers being provided with active mbhrenes and connected to each other by a conduit in which is mounted a valve actuated by the active membrane of the low pressure chamber, under the control of a rocker lever. Between the fuel intake pipe and the high pressure expansion chamber, there is also mounted a valve which is actuated by a respective active membrane, under the control

  a rocker lever. There is also a third sleeping room.

  engine idling system, fitted with an active diaphragm and connected by means of an adjusting screw to the exhaust duct

  fuel. Inside the housing, there is also a chamber

  independent preheating bre in which circulates the water supplied, through tubular inlet and outlet connections, by the engine cooling circuit. A starting electromagnet is also

  associated with the low pressure expansion chamber.

  The disadvantages of this known evaporator-regulator are manifold. Firstly, its operation is not reliable due to the rapid wear of the active membranes, due to the large temperature differences in the various operating states, also due to the large number of components which complicates the maintenance operations. and repair as well as due to the low flow authorized by the connection orifices. There is also a risk of gas leaking into the atmosphere in the event of a rupture of the active diaphragm of the high pressure expansion chamber and through the adjustment screw for idling. Accurate dosage of gaseous fuel in

  the different operating states of the engine is also im-

  possible because of the impossibility of maintaining

  constant temperature conditions in the evaporator-

  regulator. The main object of the present invention is therefore to develop an evaporator-expansion valve characterized by improved reliability in service and by easier maintenance and repair operations, as well as by eliminating the risk of leaks.

  gas in the atmosphere and by improving the mixing under conditions

  constant operating temperature.

  This object is achieved by an evaporator-regulator which comprises a casing in which are machined an inlet pipe and a fuel outlet pipe, respectively connected to two separate fuel expansion chambers, one at pressure

  high and the other at low pressure. Between the intake duct

  valve and the high pressure expansion chamber, a valve is mounted

  eg loaded by a spring. The high pressure expansion chamber is connected to the low pressure expansion chamber through a port which is also closed by a spring loaded valve. For the

  engine idling, a third fuel chamber is provided

  rant, connected to the two expansion chambers and provided with an adjustment screw. The three fuel chambers contain active membranes

  which delimit on each side of each of them independent spaces

  dants. There is also a separate preheating chamber in the housing which is connected to the engine cooling circuit by

  an inlet tubing fitting and an outlet tubing fitting. Compliance-

  In accordance with the invention, the valves located between the fuel intake duct and the high pressure chamber and between the latter and the low pressure chamber are actuated directly by the membranes.

  respective assets. The adjusting screw, associated with a spring, is

  tee immediately below the membrane of the fuel chamber assigned to the engine idling, to limit the stroke of the

  diaphragm with a regulated flow area of the orifice for the passage of the

  burant towards the high pressure chamber. In addition, the enclosed space, formed below the active membrane of the high pressure chamber, is connected, by a conduit, to the fuel space of the chamber.

  low pressure relief valve and, facing the tubular connection of

  for the preheating liquid, an electromagnetic valve is mounted

  that which is inserted into an electrical circuit with a relay and a sensor

  located in the fuel drain pipe.

  The advantages of the present invention lie in the improvement

  tion of the operating reliability of the evaporator-deterner,

  which results from the removal of narrow connecting conduits

  for the passage of fuel and rocker levers, facilitating

  thus maintenance and repair operations of the regulator.

  In addition, the risks of gas leaking into the atmosphere, in the event of rupture of the membrane of the high pressure expansion chamber and of depressurization around the system adjustment screw for idling, are eliminated, and we also obtain a level

  constant temperature for the evaporator components-

  regulator, which plays in favor of an increase in the duration of

  life of all rubber components - active membranes and seals -

and a better mix.

  A preferred embodiment of the present invention will now be described in more detail, but only by way of non-limiting example, with reference to the accompanying drawing, the single figure of which represents it in a sectional view taken along the axis of the rooms

of relaxation.

  The evaporator-regulator shown consists of two fuel expansion chambers, one A at high pressure and the other B at low pressure, these two chambers being integrated in a common casing 1 in which is further machined a conduit horizontal 2 for the fuel, which connects the gas inlet pipe to the expansion chamber A. In the entrance to this chamber, there is mounted a valve seat 3 in which is housed a valve 4 which is pushed against the seat 3 by a spring 5. The shape of the expansion chamber A is defined as follows: a membrane 6 is pinched against the casing 1 by a cover 7 on which a spring 8 acting on the valve 4 is supported by means of the membrane 6. In the expansion chamber A, a finned evaporation plate 9 is further mounted. Between the two expansion chambers A and B, there is a second valve seat 10 integral with the casing 1 and in which a second valve 11 is housed, etan t pushed back by a spring 12 against the seat 10. The shape of the expansion chamber B is defined as follows: a second membrane 13 is pinched against the casing 1 by a cover 14, and the space formed above this membrane is placed in communication with the atmosphere through an orifice provided in the cover 14, while the space situated below the membrane 13 is connected to the engine carburetor by a fuel evacuation duct 15. Inside the housing 1, an additional chamber is also provided.

  C for fuel, intended for idling the engine, and near

  mite from the valve seat 10, a cover 16 is mounted in which an orifice 17 is formed making the chamber C communicate with the chamber B. A third membrane 18 is further pinched against the casing 1 by this cover 16 and, below of this membrane 18, is arranged a spring

  19 which presses it against the edge of a hole 20 for passage of the

  burant which is machined in cover 16 and communicates with the chamber

  expansion valve A through a duct 21. On the casing 1, is furthermore

  e an adjustment screw 22 disposed facing the membrane 18 and the space

  mtié below this membrane is connected, by a tubular connection 23, to the suction pipe of the engine. In addition, a conduit 24 is machined in the cover 7 and in the casing 1, this conduit 24 communicating the space defined below the membrane 6 of the expansion chamber A with the space defined below the membrane 13 of the

  expansion chamber B. Between the casing 1 and the cover 7, is in or

  be provided a preheating chamber D which surrounds the expansion chamber

  te A and is connected, by a tubular inlet fitting 25 and a tubular outlet fitting 26, to the engine cooling circuit. Between the tubular inlet connection 25 and the casing 1, a valve is mounted

  fóechromagnétique 27 which is incorporated into an electrical circuit com-

  provided with a relay 28 and a temperature sensor 29 arranged in the

  fuel evacuation duct 15.

  The evaporator-regulator, according to the invention, operates as follows: When the engine is not running; that is to say when the pipe 2 for the fuel is not supplied with gas, the spring 8 pushes the diaphragm 6 towards the valve 4 and the latter is not applied against the valve seat 3 , the expansion chamber A thus communicating with the conduit 2. The valve 11 is in turn applied against the valve seat 10 under the action of the spring 12. The membrane 13 of the expansion chamber B is in its neutral position being given that the pressure prevailing on either side of this membrane is equal to atmospheric pressure. The membrane 18 located in the chamber C for idling has, for its part, closed the orifice 20 for supplying fuel to the connection conduit 21, under the action of the spring 19. The electromagnetic valve 27 is for its part open and

  therefore allows the preheating liquid to flow freely to the chamber.

bre D.

  When fuel gas is supplied to the evaporator-

  regulator; it passes through conduit 2 and through

  the central opening of the seat 3, thus filling the space situated above

  above the membrane 6 of the expansion chamber A and, at this instant, the liquefied gas passes into the gas phase and its pressure increases. When the force exerted by the gas on the membrane 6 becomes equal to the force of the spring 8, the membrane 6 is moved towards the cover 7 and releases the valve 4 which, under the action of the spring 5 and under the effect

  gas pressure in line 2, closes valve seat 3.

  Once the internal combustion engine is dismantled, it

  a vacuum is established in the respective mixing device which trans-

  put, through the fuel evacuation duct 15, into the space formed

  below the diaphragm 13 of the expansion chamber B. It then results from the pressure difference thus produced between the two sides of the diaphragm 13, that the latter is displaced in the direction of the valve 11 and forces the latter to release the central opening of the valve seat by overcoming the force of the spring 12. At this instant, the gas contained in the expansion chamber A penetrates into the expansion chamber B and, when its pressure becomes equal to atmospheric pressure, the membrane 13 returns to its initial position relative to the cover 14 and the valve 11 closes the seat 10 under the action of the spring 12 and

  under the effect of the gas pressure inside the expansion chamber

  te A. Following the passage of part of the gas in the expansion chamber B, the pressure prevailing in the expansion chamber A decreases and then, the spring 8 pushes the membrane 6 against the valve 4 which thus frees the opening valve seat center 3; it then enters the expansion chamber A, a new quantity of liquefied gas which evaporates and raises the pressure inside this chamber. Under the effect of the gas pressure, the membrane 6 is again moved in the direction of the cover 7, thus compressing the spring 8, while the

  valve 4 closes the central opening of the valve seat 3. The power supply

  tion in gas is thus achieved through the expansion chambers

  te A and B. The operation of the system for idling, in the evaporator-regulator according to the invention, is as follows: When idling the engine, it is established, below the butterfly valve gases in the carburetor, a vacuum which is transmitted, by

  a respective conduit and the tubular connector 23, in the space delimited

  below the membrane 18, and the latter, overcoming the force of the spring 19, moves towards the adjustment screw 22 and thus discovers the outlet orifice 20. The gas then passes from the expansion chamber A into the chamber expansion valve B, flowing through the connection duct 21 and the orifices 20 and 17 and, from the expansion chamber B, it enters the carburetor passing through the duct 15. The quantity of gas delivered is determined by the distance "a" between the adjusting screw

22 and the membrane 18.

  For the evaporation of the liquefied gas in the evaporator-regulator,

  we use the heat dissipated by the circulating liquid

  engine cooling cooked, which circulates, in the pre-

  heating D formed in the housing 1. To guarantee a constant temperature

  aunt with gas leaving the evaporator-regulator, and- influ-

  ink the load factor of the motor favorably and increase

  also ter the service life of the membranes and rubber seals,

  an automatic regulation system is also provided which operates

  ne as follows: the temperature sensor 29 records the temperature of the gas leaving the evaporator-expansion valve and, in the event of a temperature variation, the relay 28 is activated and switches

  in the direction of '' opening or closing the electromagnetic valve

  that 27 which regulates the admission of the preheating liquid into the chamber D. The preheating chamber D only envelops the expansion chamber A, because it is there that the liquefied gas must evaporate most intensively. The evaporation process is also intensified by the evaporation plate 9 which increases the heat exchange surface. The function of the conduit 24 attached to the expansion chamber A-is as follows: in the event of an emergency, such as for example following a rupture of the membrane 6, the gas passes through it and enters the conduit 24 from which it is transferred into the space of the expansion chamber B, which is connected to the carburetor of the engine. We avoid

  sort of gas leaks into the atmosphere.

Claims (1)

CLAIM   4-Evaporator-regulator comprising a housing (1)   in which an intake duct (2) and an exhaust duct are machined   cuation (15) for fuel, respectively connected to a high pressure expansion chamber (A) and to a low pressure expansion chamber (B), and in which a valve (4,11), loaded by a spring ( 5, 12), is mounted, on the one hand, between said intake duct (2) and the high pressure expansion chamber (A) and, on the other hand, between the   two relaxation chambers (A, B), while at these two relaxation chambers   tent is connected to a third chamber (C) for idling the engine, provided with an adjustment screw (22), and that in the three chambers are mounted active membranes (6,13,18), a preheating chamber (D) provided with an inlet tubular connection (25) and an outlet tubular connection (26) for the preheating liquid being further provided around the high pressure expansion chamber ( A), characterized in that the valves (4,11) are actuated directly by the respective mebs (6,13), in that the adjusting screw (22), associated with a spring (19), is mounted below the membrane (18) of the chamber (C)   assigned to idling the engine, in that the space formed   below the active membrane (6) of the high pressure expansion chamber (A) is connected by a conduit (24) to the space formed below the active membrane (13) of the low pressure expansion chamber   (B) and in that, facing the inlet tubing connection (25) for the liquid   preheating, is mounted an electromagnetic valve (27) which is inserted into an electrical circuit with a relay (28) and a sensor   temperature (29) placed in the fuel evacuation pipe (15).