FR2653179A1 - EXHAUST GAS RECYCLING VALVE FOR A THERMAL ENGINE. - Google Patents

Abstract

The known exhaust gas recycling valves for thermal engines, in particular for automobile use, consist of a body (2) with an exhaust gas channel (3) having an inlet region, a seat region of valve and an outlet region, and a valve head (7), the rod (8) of which protrudes from the body and is connected to a membrane (12) of a membrane box (13), the chamber of which can being evacuated has a spring (16) exerting on the diaphragm and therefore on the valve a force in the direction of the valve seat tend to be noisy due to pulsations of the exhaust gases. To remedy this, the exhaust gas recycling valve according to the invention comprises magnetic means (18, 22) capable, in the closed position of the valve, of exerting a closing force on the latter.

Description

The present invention relates to a gas recycling valve

  exhaust for an internal combustion engine, consisting of a body with an exhaust gas channel comprising an inlet region, a valve seat region and an outlet region, and a valve head cooperating with the seat and whose rod protrudes from the body and is connected

  to a membrane of a membrane box whose chamber suscep-

  tible to be evacuated presents a spring which exerts on the membrane and therefore on the valve a force in direction

valve seat.

  Exhaust gas recirculation valves of this kind, known for example from the German utility model No

  8714505.7 are used to order a recycling of exhaust gas

  depending on the state of charge of the heat engine, in order to reduce various pollutants in the exhaust gases, such as nitrogen oxides and by recycling

  also partly carbon monoxide and hydrocarbons

  bures, which form during the combustion of the mixture

bustible.

  In these exhaust gas recirculation valves there is

  do however in certain regions of the character diagram

  téristique of the engine, as a result of the gas pulsation

  exhaust, vibrations of the spring-mass system.

  The valve stem then oscillates with the diaphragm, the valve head and the spring at the frequency of the motor, so that in the interval just before the opening and closing of the valve head on the valve seat necessarily make annoying noises due to the upper part of the valve head and the body

  or the valve head and the valve seat collide

quent quickly.

  Consequently, the object of the present invention is to provide an exhaust gas recycling valve of the defined type.

  above, so that this disadvantage does not occur

duise more.

  This object is achieved according to the invention with regard to an exhaust gas recycling valve for an engine.

  thermal, consisting of a body with an exhaust gas channel

  Pement having an inlet region, a valve seat region and an outlet region, and a valve head cooperating with the valve seat and whose rod protrudes from the body and is connected to a diaphragm a membrane box whose chamber capable of being evacuated has a spring acting on the membrane and

  so on the valve an effort towards the seat of support

  pope, by the fact that the valve is stressed, in its closed position, by additional means exerting

  a closing force, the diaphragm box can advantageously

  carefully in the closed position of the valve be

  vented through a throttle.

  One embodiment of the exhaust gas recycling valve according to the invention consists in that the additional means exerting a closing force consists of a magnet which is mounted in the membrane box and cooperates with constituent elements of the valve that act as a frame. The magnet being produced either as an electromagnet controlled by an electric control device, or as a permanent magnet. In the latter case, the permanent magnet is advantageously mounted on a

  axially displaceable carrier plate by an adjusting screw.

  In the case where in the valve closed position

  the membrane box is vented through

  diary of a constriction, the valve stem acts advantageously-

  ment on equipment with adjustable valve.

  The invention is based on the thesis that the noise produced

  by the exhaust gas recirculation valve is favored

  laughed in particular in the lower part of the stroke by a characteristic curve of relatively flat opening. Thanks to the additional closing force acting in this region on the valve, the noise produced can

  to be avoided to a large extent. For this, an electro-

  magnet is mounted and supplied with current via a control unit according to certain parameters

  of the motor (e.g. speed, load, temperature

  erasure, etc.), so that it becomes possible

  using magnetic force to vary the character

  valve specification as a function of load and / or speed of rotation. Thus, in the lower part of the characteristic curve, a jump or discontinuity function is established, so that the valve head lifts up a little later than normal but in an accelerated manner.

  as a result of the valve seat and arises during the process

  known to close earlier and jump on the valve seat.

  In a simpler and less expensive variant one or more

  permanent magnets, which are mounted in such a way

  on a magnet carrier plate only during the process of

  exhaust gas recirculation valve

  the magnetic force acts against the pneumatic force

  tick produced by the vacuum in the control pressure space, take on the task of varying the characteristic curve. When the balance of forces is exceeded, an abrupt functioning occurs, of the kind

  jump, and the valve head lifts accordingly quickly-

  ment of its seat. The intensity of the jump depends on the magnetic force and the air gap in the magnetic circuit and is made adjustable by an adjusting screw which is connected to the magnet holder. Advantageously, it can thus also be compensated for tolerances. An advantage also consists in obtaining an extension of the service life of the valve since the fact that the beat, repeated in the manner of pulsations, of the valve head against the seat is reduced. The wear of these building elements

is reduced.

  An effect similar to that obtained for the two exemplary embodiments described above can also be obtained with an embodiment in which the valve stem is connected to an adjustable valve device which is open in the closed position of the valve. so the box

  membrane is vented through a shutter

  payment. Opening the valve closes

  the valve equipment connected to it and it

  causes a sudden drop in control pressure and, therefore, a jump or discontinuity function of the curve

opening characteristic.

  Examples of embodiment of the invention are described below with reference to the accompanying drawings in which: - Figure 1 shows, in section, an exhaust gas recycling valve;

  - Figure 2 shows, in section, another form of realization

  sation of an exhaust gas recycling valve; and - Figure 3 shows, also in section, a third

  embodiment of a gas recirculation valve

exhaust.

  Figure 1 shows an exhaust gas recycling valve

  part 1 for a heat engine, the valve being formed by a body 2 which is designed to be attached to the engine and has an exhaust gas channel 3 with an inlet region 4, a seat region valve 5 and an outlet region 6. The valve seat 5 cooperates with a valve head 7 whose rod 8 protrudes partially from the body 2 and is guided in a guide sleeve 10 fitted in an opening 9 of the body. The valve stem 8 projecting from the body 2 is connected by means of two membrane discs 11 to a membrane 12 of a membrane box 13 fixed to the body 2 and the chamber of which can be evacuated by the 'through a pressure fitting 14, receives a membrane spring 16 bearing on the one hand in the dome-shaped upper part of the chamber 15 and on the other hand on the disc

membrane 11.

  An electromagnet 18 which, mounted on a support plate 17

  at the level of the socket 8 and engaging around the former

  outer end of the valve stem 8, is constituted by an electric coil 19 fitted with a core 20 with

  magnetic return and a magnetic return plate 21 coo-

  father with a pot forming a frame 22 fixedly connected

  to the upper diaphragm disc 11 and is controlled by the

  conductor 23 via a control unit

  24 to which functional parameters can be communicated

  motor operation (eg speed, load, motor temperature, etc.), so that it is possible, for example depending on the speed and load, to vary the magnetic force and thus adjust the jump function, or discontinuity, of the valve stem 8. Other positions of the electromagnet 18 on or in the exhaust gas recycling valve

are also conceivable.

  Another embodiment of an exhaust gas recycling valve 1 of a construction similar to that of FIG. 1 is shown in FIG. 2. Several

  permanent magnets 25 are mounted on a holder plate

  magnets 26 which can be axially displaced via

  diary of an adjusting screw 28 which can be locked with a lock nut 27. The magnet holder plate 26 and the permanent magnets 25 form, with a pot forming a magnetic return 29, mounted on the membrane disc 11, a gap 30, so that the intensity of the jump, or discontinuity, of the characteristic opening curve depends on the importance

  of this air gap and the magnetic force of the permanent magnets

  nents. By displacement of the permanent magnets 25 in the magnetic circuit (variation of the air gap), the intensity of the jump, or discontinuity, becomes adjustable and tolerances

can be compensated.

  FIG. 3 shows a third embodiment of an exhaust gas recycling valve in which the valve stem 8 is connected by means of a tension spring 31 to the shutter 32 of a piece of equipment valve 33, which can be screwed into the chamber 15, capable of being evacuated, of the membrane box 13. In the closed state, the membrane box 13 is vented by means of a throttle 34 of the valve equipment 33. During the opening process, when the valve head 7 is raised from the seat 5, the valve equipment 33 closes so as to obtain a sudden drop in pressure command and, consequently, a jump function,

  or discontinuity, of the characteristic opening curve.

Claims (7)

Claims   1.- Exhaust gas recycling valve for engine   thermal, consisting of a body with an exhaust gas channel   Pement having an inlet region, a valve seat region and an outlet region, and a valve head cooperating with the valve seat and whose rod protrudes from the body and is connected to a diaphragm a diaphragm box whose chamber capable of being evacuated has a spring which exerts on the diaphragm and therefore on the valve a force in the direction of the valve seat, characterized in that the valve is stressed, in the closed position , by additional means   (18; 25) exerting a closing force.   2.- Exhaust gas recycling valve according to the resale   dication 1, characterized in that the means for exerting a closing force is formed by a magnet which is mounted in the membrane box (13) and cooperates with elements (22,29)   components of the valve which play the role of reinforcement.   3.- Exhaust gas recycling valve according to the resale   dication 2, characterized in that the magnet is designed as an electromagnet (18) which is controlled by a device electrical control (24).   4.- Exhaust gas recycling valve according to the resale   dication 2, characterized in that the magnet is made as a permanent magnet (25).   5.- Exhaust gas recycling valve according to the resale   dication 4, characterized in that the permanent magnet (25)   is mounted on an axially distributed magnet carrier plate (26)   adjustable by an adjusting screw (28).   6.- Exhaust gas recycling valve according to the pre-   Ambule of claim 1, characterized in that, in the closed position of the valve, the diaphragm box (13) is vented by means of a throttle (34).   7.- Exhaust gas recycling valve according to the resale   dication 6, characterized in that the valve stem (8)   acts on equipment with adjustable valve (33).