FR2545539A1 - PILOT SYSTEM FOR RECYCLING EXHAUST GAS IN THE SUCTION TUBE OF AN INTERNAL COMBUSTION ENGINE - Google Patents

Abstract

THIS EXHAUST GAS RECYCLING PILOT SYSTEM IN THE VACUUM TUBE 2 OF AN INTERNAL COMBUSTION ENGINE HAS AN EXHAUST GAS VALVE 7 WHICH CONTAINS A MEMBRANE 9 WITH THE CHAMBER 11 SUBJECTED TO A CONTROL PRESSURE GENERATED BY PRIMARY CONTROL VALVE 14. THE OPENING CHARACTERISTIC WHEN THE INCREASED ENGINE LOAD DEPENDS ON THE CONSTANT OF SPRING 12 OF EXHAUST VALVE 7 WHILE THE CLOSURE CHARACTERISTIC IS FUNCTION OF THE REPORTING OF THE ACTUAL SURFACES OF TWO MEMBRANES RIGIDALLY CONNECTED TO THE OTHER IN THE PRIMARY CONTROL VALVE 14.

Description

1 - The present invention relates to a pilot system for recycling gases

exhaust in the tubing

  of an internal combustion engine, this system

  including an exhaust gas valve

  in a recycle line and constituted by a valve and a membrane connected thereto and subjected to the action of a spring, the diaphragm chamber of this

  valve being, through a-conduct of

  a control pressure on which a primary control valve with two

  rooms separated by a membrane.

  Pilot schemes of this kind serve to

  kill an exhaust gas recycle according to the engine's internal combustion engine, in order to limit

  the emission of various harmful substances into the exhaust gas

  particularly the emission of nitric oxides, hydro-

  carbides and carbon monoxide The effect of such a re-

  cycling is generally known and several pilot systems have already been designed and put into operation on

  internal combustion engines fitted to vehicles.

  The patent application DE 2,362,359 describes a system

  very simple pilot system consisting of an exhaust valve installed in a

  recycling line and a valve for setting

  mosphere controlled by the throttling device of a carburettor With the venting valve can be generated in the diaphragm chamber subject to

  at the suction pressure of the internal combustion engine

  dull, for the pneumatic maneuvering of the exhaust valve, a mixed pressure by which

  this valve is controlled in such a way that it

  an exhaust gas recirculation corresponding to

a known characteristic curve.

  Patent DE 2 315 734 discloses another pilot system in which the gas valve

  The exhaust system is also equipped with a single

  brane and subjected to a mixed pressure composed of the

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  suction pressure and atmospheric pressure, this mixed pressure being generated by a primary control valve operating according to the pressure

exhaust gas.

  In addition, various systems are known

  exhaust gas recirculation gulators, for example

  From that described in patent DE 2528760 But these systems are equipped with gas valves

  exhaust systems, composed of several members

  branes and which can be operated only with considerable regulating equipment, so that these systems can not be compared if only for reasons of price to the pilot systems whose exhaust valve comprises only one

only membrane.

  These pilot systems are relatively inexpensive to

  realize are, however, not exempt from some

  which may adversely affect the action of the recy-

  exhaust cling on harmful substances and

  Correct design of the internal combustion engine In particular, this concerns, on the one hand, the wear to which the venting valve is subject and which makes the recycling of the exhaust gases deviate from the curve. theoretical, on the other hand of the air supply

  parasite in the suction tubing, especially when

  the engine is idling or close

  of idling, this parasitic air not passing through the car-

  thus causing, in the two known pilot systems, variations in engine speed and deviations from the values on which

  the exhaust gases were set to idle.

  The object of the invention is therefore, starting from a system

  pilot scheme of the species described in the preamble, to

  so that said disadvantages are removed.

  To achieve this object, the invention has provided the following provisions: a) one of the chambers of the primary control valve

  is connected through a line

  of the suction pipe upstream of a throttle valve and, via the control line, to the exhaust valve, while the other chamber is, via a pipe, connected to the section of this pipe downstream of said butterfly, b) said other chamber is isolated from the atmosphere by a second membrane which is rigidly connected to the first membrane by a connecting piece, has a

  effective area larger than this first mem-

  brane and is prestressed against atmospheric pressure

  by an adjustable spring, and c) in the part which connects the two membranes to one another is arranged a plate forming a valve which is subjected to the action of a spring and controls on the one hand a mouth, located in the body of the primary control valve, said pipe connected to the section of the suction pipe upstream of said butterfly, on the other hand a valve seat of a section

  tube of said connecting piece connected to the atmosphere.

  phere. The advantage provided by these provisions is that it is possible to use an exhaust valve which has only one membrane, not subject to wear and no supply of unwanted air This results

  a constant speed of the engine at idle speed and a

  longer in time of body fractions

harmful (CO) exhaust gases.

  An exemplary embodiment of the invention is described below with reference to the accompanying drawing; on this last

  FIG. 1 is a diagram of a combustion engine

  internally equipped with a pilot system according to the invention.

  tion, and FIG. 2 is a sectional view of the valve of

  primary control of the pilot system according to fig 1.

  The internal combustion engine 1 is equipped with a Dira tion 2 astern pipe and a throttle valve 3 and sue exhaust gas pipe 4, said butterfly 3 can be part of a mixture preparation device which has not been shown in

  drawing A recycling line 5 derives from

  exhaust pipe 4 which opens into a section 6

  of the suction pipe 2 downstream of the butterfly

  tranglement 3, an exhaust valve 7 being disposed in the path of the recycle line 5

  to order the section This valve 7 is constituted

  killed by a valve 8 and a membrane 9 connected to this valve; it is housed in a body 10 which forms a

  membrane chamber 11 in which is disposed a

  fate 12 which urges the membrane 9 in the direction

  The diaphragm chamber 11 is connected via a control line 13 to a primary control valve 14 which is itself connected via lines 15, 16 to a section 17.

  of the suction pipe 2 located upstream of the papillary

  3 and the section 6 of the same pipe downstream of this butterfly The mouth of the pipe 15 in the section 17 of the suction pipe 2 located upstream of the butterfly 3 passes c 8 downstream of the latter, so in the section 6, when the throttle valve 3 is opened, so that this mouth is subjected to the depression of the engine and that the latter is transmitted both by the pipe 15 and by the pipe 16 to the valve of

primary control 14.

  FIG. 2 shows the primary control valve 14 in its body 18 in which two membranes 19, 20

  which have unequal effective surfaces and are

  rigidly connected to one another by a connecting piece 21 subdivide this body into three chambers 22, 23 and 24 The chamber 22 communicates through an opening with the atmosphere; the chamber 23 is connected by the pipe 16 to the section 6 of the suction pipe 2, and the chamber 24 is connected via

  line 15 to section 17 of the suction pipe.

  and via the control line

  13 at the exhaust valve 7.

  In the chamber 24 a spring 25 adjustable by means

  a corner 32 and a screw 33 tends to repel the members

branes 19, 20 to the chamber 22.

  The connecting piece 21 of the membranes 19, 20 is

  designed as a hollow body and has a section

  axial tubular section 28 forming a seat 26 for a plate-shaped valve 27 This axial tubular section 28 opens via a filter lining

  29 in the chamber 22 communicating with the atmosphere.

  When the suction pressure prevailing in the chamber

  23 is not low enough to cause a displacement.

  cementing the membranes 19, 20 against the force of the spring in the chamber 24, the plate 27 is applied by a spring 30 to the valve seat 26: formed in the connecting piece 21 A displacement of the membranes 19,

  20 is made possible by the membrane 20 which has the

  largest effective face, and this displacement continues, when the suction pressure has reached

  a corresponding value less than the pressure

  mospheric, until valve 27 comes into effect

  against the mouth 31 of line 15 connected to the

  section 17 of the suction pipe 2; this stamp

  is then blocked If the suction pressure is

  ration continues to decline, the displacement of

  branes 19, 20 continues and the plate 27 is separated from its seat 26 in the connecting piece 21, against the force exerted on it by the spring 30.

  this being the case, the chamber 24 is put under atmospheric pressure.

  phérique by the tubular section 28 in the room of

liaison 21.

Description of operation

  When the internal combustion engine is idling, there prevails in the section 6 of the suction pipe 2 located downstream of the throttle valve 3 a low suction pressure which propagates in the chamber 23 by the intermediate of the pipe 16, so that the resulting forces exerted thereby on the membranes 19, 20 (the membrane 20 has an effective area greater than that of the membrane 19) has exceeded the force of the spring 25 and applied the connecting piece 21 with the valve plate 27 against the mouth 31 of the pipe 15, at the same time as the plate 27 has disengaged the valve seat 26 in the connecting piece 21 Therefore, a setting of 1 atmosphere of the chamber 24 and, through the control line 13, the diaphragm chamber 11 of the exhaust valve, so that the valve is closed and no exhaust gas flows

by the recycling line 5.

  When the internal combustion engine is running at full speed, there is a high suction pressure, insufficient to overcome the force of the spring 25, so that the connecting piece 21 with the plate forming

  valve 27 is remote from the mouth 31 and that

  For this reason, the chamber 24 is no longer at atmospheric pressure, but subjected to the suction pressure because, as a result of the position

  throttle full throttle 3

  of the pipe 15 in the suction pipe 2 is now located in the section 6 downstream of

  this butterfly This suction pressure acts, by the in-

  intermediate of the control line 13, also in

  the diaphragm chamber 11 of the exhaust gas valve 7

  but does not cause displacement of the membrane 9

  against the force of the spring 12; this valve is therefore

  When the engine load falls, the suction pressure goes down until the diaphragm 11 is moved against the force of the spring 12, so that the valve 7 opens up more and more. mesufre that the

  engine load continues to decrease, depending on

6 -

  the characteristic of the spring and until a maximum of

mum be reached.

  In the lower partial load range the displacement of the connecting piece 21 in the primary control valve 14 into the field of contact between the plate 27 and the mouth 31 generates a mixed pressure composed of the suction pressure and

  atmospheric pressure, this mixed pressure increases

  as the suction pressure decreases, so that the spring 12 in the exhaust valve 7 overcomes the force of the diaphragm and starts the closing movement of the valve 7 of the

exhaust gas.

-S - R WYID 7 CA-ITO 8s S

  1 Ovstème pilote to recycle Laz of Escape

  in the induction pipe (2) of an internal combustion engine, comprising an exhaust valve (7) installed in a recirculation pipe (5) and consisting of a valve (8) and a diaphragm (9) connected to it and subjected to the action of a spring, the diaphragm chamber (11) of this valve being, via a control line (13), subjected to a pressure of control on which influences a primary control valve (14) having two chambers (23, 24) separated by a diaphragm (19), this pilot system is N tremarquablee N what it meets the following features:

  a) one (24) of the chambers (23, 24) of the

  primary mandrel (14) is connected via a line (15) to the tubular section (17)

  suction nozzle (2) upstream of a throttle

  (3) and, via the control line (13), to the exhaust valve (7),

  while the other chamber (23) is, through

  diaire of a pipe (16), connected to the section (6) of this pipe downstream of said butterfly; b) the said other chamber (23) is sealed with respect to the atmosphere by a second membrane (20) which is rigidly connected to the first (19), has an effective surface area greater than that of the first membrane (19); ) and is prestressed

  against atmospheric pressure by a spring

  25), and c) in the connecting piece (21) of the two diaphragms (19,) is disposed a valve plate (27) which is subjected to the action of a spring (30) and controls a mouth (31) located in the body (18) of the primary control valve (14), said pipe (15) connected to the section (17) of the

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  intake pipe (2) upstream of said throttle valve (3), on the other hand a valve seat (26) of a tubular section (28) of said connecting piece

(21) connected to the atmosphere.

  2 pilot system for recycling exhaust gas according to claim 1, characterized in that said adjustable spring (25) can be adjusted by means of an adjusting screw (33) acting on it via a corner (32) and a

inclined plane (33).