Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/52—Systems for actuating EGR valves
  • F02M26/53—Systems for actuating EGR valves using electric actuators, e.g. solenoids
  • F02M26/54—Rotary actuators, e.g. step motors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/65—Constructional details of EGR valves
  • F02M26/70—Flap valves; Rotary valves; Sliding valves; Resilient valves

Definitions

• the present invention relates to a valve for controlling the quantity of exhaust gas recycled in an exhaust gas recirculation system of an internal combustion engine.
• Exhaust gas recirculation (EGR) systems are already known intended, in internal combustion engines, to recycle part of the exhaust gases at the intake into the cylinders.
• EGR exhaust gas recirculation
• Such recycling of gases, generally inert, and therefore not participating in combustion, makes it possible to lower the combustion temperature, which has the effect of reducing the rate of nitrogen oxides (NOx) present in exhaust, and therefore to limit the pollution caused by such an engine.
• NOx nitrogen oxides
• valve of the type comprising a disc that is movable in rotation and provided with a light cooperating with a fixed orifice, and motor means for driving this disc in rotation, in particular a stepping motor.
• the present invention aims to overcome these drawbacks.
• the subject of the invention is a valve for controlling the quantity of exhaust gas recycled into an exhaust gas recirculation system of an internal combustion engine, characterized in that it comprises a shutter member disposed in a duct to cooperate in a substantially sealed manner, in the closed position, with a stop member, and rotary actuating means for driving said shutter member from its closed position to an open position, said means rotary actuator comprising a stator and a rotor provided, one with at least one magnet and the other with at least one control winding, the stator and the rotor being mounted so that in the absence current in the control winding, the shutter member is pressed against the stop member at least partially by the residual magnetic forces.
• the effort of applying one member to the other is therefore provided at least partially or entirely by the magnet.
• the shutter member is driven directly by said rotary actuating means.
• the shutter member can be a flap mounted in said conduit on the axis of rotation of the rotary actuating means. More particularly, the walls of said duct can form two shoulders in opposite directions on either side of the axis of the flap, said shoulders forming abutment members and cooperating with the edges of the flap to provide sealing.
• the shutter member is driven by said rotary actuating means via a cam.
• This embodiment has the advantage that one can choose as desired the stroke of the shutter member according to that of the actuating means.
• the shutter member can be a valve arranged to be driven in translation by said rotary actuating means via said cam.
• Said cam may comprise a first substantially cylindrical part secured to the shutter member and blocked in rotation, on which helical grooves are formed arranged to cooperate with balls arranged in cells of a second piece secured to the actuating means rotary and locked in translation.
• Said cam can also be formed at the end of a lever mounted on the axis of rotation of the drive means and cooperates with a shoulder of the valve stem.
• said cam comprises a first part secured to the rotary actuating means, on which helical grooves are formed arranged to cooperate with rollers mounted on a second piece locked in rotation and secured to the member shutter.
• the valve according to the invention comprises a helical ramp coaxial with the output shaft of the rotary actuating means and driven in rotation by said actuating means, arranged to cooperate with a follower roller cam likely to cause the shutter member.
• FIG. 1 is a perspective view of a valve according to a first embodiment of the invention
• FIG. 2 is another perspective view, in section, of the valve of Figure 1;
• FIG. 3 is an exploded perspective view of a valve according to a second embodiment of the invention.
• - Figure 4 is an axial sectional view of the valve of Figure 3;
• - Figure 5 is a perspective view, in section, of a valve according to a third embodiment of the invention.
• FIG. 6 is an axial sectional view of the valve of Figure 5, mounted on a mounting support;
• FIG. 7 is a graph illustrating the operation of the invention.
• FIG. 8 is an exploded perspective view of a valve according to another embodiment of the invention.
• FIG. 9 is an axial sectional view of the valve of Figure 8.
• FIG. 10 is an exploded perspective view of a valve according to yet another embodiment of the invention.
• FIG. 11 is an axial sectional view of the valve of Figure 10.
• FIG. 12 is an axial sectional view of a valve according to yet another embodiment of the invention
• the valve of Figures 1 and 2 essentially comprises a motor 1 of a type which will be described below -after and, mounted on the output shaft of this motor, a shutter 2.
• the shutter 2 pivots in a duct shown diagrammatically by the dashed lines 3, this duct being connected to the valve by the flange 4 in which the shutter 2 is swivel mounted. It can be seen more particularly in FIG. 2 that the shutter 2 is capable of pivoting by a quarter of a turn between a completely open position, where it is parallel to the duct 3, and a completely closed position, where it is perpendicular to this duct and bearing on abutment surfaces 5 formed in the flange 4.
• the abutment surfaces 5 are perpendicular to the axis of the duct 3 and are directed one in one direction, and the other in the opposite direction, so that the edges of the flap 2 are supported on these two surfaces 5 when it is closed, thus forming a seal.
• the gas pipe is formed by a first cylindrical pipe 10 of relatively large section, into which a second substantially cylindrical pipe 11 opens, of smaller diameter and whose axis is substantially perpendicular to the axis of the cylinder 10.
• the two conduits are here made in one piece.
• the end 12 of the conduit 11 inside the cylinder 10 supports a valve seat 13 to form a seal with a valve head 14.
• the part constituted by the cylinders 10 and 11 is extended opposite the cylinder 11 by a housing 15 opening into the cylinder 10 to receive the actuation mechanism of the valve 14.
• the housing 15 is itself extended by a housing 16 capable of receiving the actuating motor of the aforementioned mechanism, this motor not being shown in the figures but being of the type described below.
• a bell 17 is mounted integral with the output shaft of the engine and is therefore locked axially.
• This bell 17 has holes 18 capable of receiving balls 19. Consequently, the motor drives the balls 19 in rotation in a plane perpendicular to the axis of this motor.
• the balls 19 are also engaged in helical tracks
• the part 21 also comprises an inner bush 25 in which the rod 26 of the valve 14 is fixed after this rod has passed through the guide part 23.
• the tracks 20 may of course not be helical in the strict mathematical sense of the term, so that the valve lift is not necessarily proportional to the angle of rotation of the motor, but can be adjusted at will by an appropriate conformation tracks.
• the valve of Figures 5 and 6 is also a globe valve.
• the valve actuation mechanism is here housed in a substantially cylindrical housing 30 and is actuated by a motor 31, the operation of which will be described below.
• the actual valve 32 is arranged to cooperate with a valve seat 33 disposed at the end of a tubular conduit 34 formed in the axial extension of the housing 30.
• the tubular conduit 34 is arranged to be engaged in a first bore 35 of a support piece 36.
• This tubular conduit 34 also comprises a lateral orifice 37 disposed opposite a second bore 38 formed in the part 36 with its axis pe ⁇ endicular to that of the first bore 35.
• the valve 32 consequently controls the flow of fluid in the bores 35 and 38.
• the rod 39 of the valve 32 is guided by a guide member 40 mounted in the housing 30.
• This rod has its free end comprising a shoulder 41 arranged to receive one end of a helical spring 42, the other end of which bears on the bottom 43 of the housing 30.
• the end of the rod 39 forms another shoulder 44 oriented towards the valve 32 opposite to the shoulder 41.
• This shoulder 44 cooperates with cam surfaces 45 of a cam 46 mounted on the output shaft 47 motor 31.
• the motors 1 16, 31 used in the three embodiments which have just been described are of the angular solenoid type, which comprise a rotor and stator provided one with at least one magnet and the other with at least one control winding.
• the control winding is supplied with voltage slots with constant frequencies and variable duty cycle (RCO).
• RCO variable duty cycle
• the current which results from the application of these voltage slots is substantially constant with a few undulations.
• This motor is here always associated with elastic return means which have only been shown here in the third embodiment in the form of the compression helical spring 42.
• FIG. 7 illustrates the characteristic curves of these motors, the torque being represented as a function of the angular elongation for a certain number of average intensities. It can be seen that this motor provides constant torque over a certain angular range ⁇ ,, ⁇ 2 for a given value of the intensity. More particularly, this torque is zero for a zero current and increases as a function of the intensity which traverses the control winding. If we observe the curve with zero current, we observe that, on both sides of the range ai, ⁇ 2 the torque takes a non-zero value which tends to bring the rotor into an angular position of equilibrium 0: 3 or ⁇ 4 where, again, the torque is zero.
• the motor has an indifferent equilibrium range ai, 0.2 and, on either side of this range, two equilibrium points 0: 3, 04.
• the elongations ⁇ 3 and or are also zero torque equilibrium points.
• the angular elongation of equilibrium against the action of the return spring is between ai and 0: 2, depending on the intensity.
• the equilibrium points 0.3 and or correspond to the case where the poles of the magnets are interposed with those of the windings at equal distance from each other.
• the indifferent equilibrium range ai, ⁇ 2 corresponds to the case where these poles at least partially overlap.
• the stator of the motor is calibrated relative to the structure of the valve so that, in the absence of current in the control winding, that is to say for an RCO equal to 1, the torque applying the flap 2 to its stops 5 or the valves 14, 32 on their seats 13, 33 either maximum or close to its maximum, as for example with a respective setting equal to 015 or 05.
• This gives maximum sealing without supplying any current. It is observed that, on the other hand, it will be necessary to provide a certain minimum intensity for detaching the flap or the valve from its seat, for example a current I, for an initial setting of ⁇ without taking account of the force exerted at the origin by the spring.
• FIGs 8 to 1 1 show variants of the embodiment of Figures 3 and 4, in which an engine of the same type as described above is used.
• the rotation stop of the member 121 (homologous to the member 21 of Figures 3 and 4) is obtained not using balls, but using of fingers 122 integral with the fixed guide member 123 and passing through the member 121. This crossing is effected by oblong holes 124 elongated radially to avoid hyperstatism which would risk jamming the member 121.
• the drive in rotation is obtained by balls 219 cooperating with helical tracks 220, as before.
• a sealing bell 125 is mounted integral with the valve to cooperate with the guide member 123 and prevent a rise of the gases along the valve stem.
• rollers 219 are crimped in a support 224 secured to the valve stem, and the member 221 is rotated by the motor. This rotation of the member 221 consequently causes an axial displacement of the support 224, and therefore of the valve.
• This arrangement has the advantage of avoiding the use of balls, relatively difficult to assemble, and which can cause jamming due to the components of radial forces which they induce.
• a helical ramp 301 coaxial with the motor shaft is rotated by this motor.
• This ramp is arranged to push a roller 302 integral with the rod 303 of the valve 304, against the action of a spring 305.
• the ramp could also be double-acting, and therefore positively drive the valve in both directions. It will be noted that, in the embodiments of FIGS. 10 to
• valve is mounted in the opposite direction to the previous embodiments.
• the casing therefore has a mounting orifice, closed by a plug 306.
• the opening and closing of the valve are produced by a rotary motor.
• This motor is here such that in the absence of control current, the valve is kept closed by the residual magnetic forces.
• the advantages of this solution could be waived by using elastic means in all of these valves as in the prior art.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Exhaust-Gas Circulating Devices (AREA)
• Valve Device For Special Equipments (AREA)
• Electrically Driven Valve-Operating Means (AREA)
• Magnetically Actuated Valves (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=9492108

Family Applications (1)

Country Status (6)

Cited By (2)

Families Citing this family (5)

Family Cites Families (4)

• 1996
  • 1996-05-14 FR FR9605974A patent/FR2748780B1/fr not_active Expired - Fee Related
• 1997
  • 1997-05-14 EP EP97924094A patent/EP0918925B1/de not_active Expired - Lifetime
  • 1997-05-14 AU AU29671/97A patent/AU2967197A/en not_active Abandoned
  • 1997-05-14 WO PCT/FR1997/000856 patent/WO1997043538A1/fr active IP Right Grant
  • 1997-05-14 AT AT97924094T patent/ATE215671T1/de not_active IP Right Cessation
  • 1997-05-14 DE DE69711639T patent/DE69711639T2/de not_active Expired - Fee Related

Non-Patent Citations (1)

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