FR2926126A1 - Three-way control valve for comburent intake system of exhaust gas recirculation internal combustion engine in vehicle, has closing unit that is driven with temporal phase shift relative to driving of another closing unit by driving part - Google Patents

Abstract

The valve (10) has two closing units arranged in two inlet ways (1, 2) of the valve, respectively, where the closing units occupy opening, closing and intermediate positions. One of the closing units drives the other closing unit into the closing or opening position, and is driven into the closing or opening position by a driving part. The latter closing unit is driven with a temporal phase shift relative to the driving of the former closing unit. The former closing unit is in the form of a closing flap (121), and the latter closing unit is in the form of a closing head (131).

Description

The invention relates to a three-way valve in an oxidizer intake system of an internal combustion engine with exhaust gas recirculation (EGR).

Traditionally, a three-way valve is used downstream of the engine to receive, on a single inlet, a flow of exhaust gas from the engine. This input stream is separated by the valve into two output streams directed respectively to a recirculation line, for injecting a fraction of the exhaust gas into the engine intake pipe, and to an exhaust pipe.

The downstream and upstream terms are defined as a function of the flow direction, the gases moving from upstream to downstream in a pipe.

In order to reduce nitrogen dioxide emissions, it is known to recirculate the exhaust gases in a recirculation line, redirecting a fraction of the exhaust gases to the engine outlet in the inlet pipe upstream. of the motor. This recirculation has the effect of slowing down the combustion of the mixture and absorbing a portion of the calories, which decreases the combustion temperature and the emission of nitrogen dioxide. In order to further reduce the combustion temperature during operation of the engine with high load, that is to say at high engine speed, the exhaust gases are generally cooled by means of an EGR heat exchanger.

The valve disposed at the exhaust is subjected to high temperature and pressure stresses because the exhaust gases are at a high temperature after combustion in the engine and are expelled with a high speed. It is therefore necessary that the valve is made of materials resistant to these constraints. Such valves, not to mention their price, are complex to assemble and maintain.

It is also known three-way valves disposed in the intake pipe upstream of the engine. These valves receive on their two inputs a flow of fresh air from outside and a flow of recirculated exhaust gas from the recirculation pipe. The valve is subjected to lower temperature stresses since the recirculated gases are cooled by the EGR heat exchanger in the recirculation line. The use in intake of a valve for the exhaust is not suitable, because a three-way exhaust valve is only usable with one inlet and two outlets, while a valve on the intake comprises two entrances and an exit. In addition, such a valve has a high cost and does not measure the fraction of exhaust gas to mix with fresh air.

This is why the applicant has sought to develop a new type of three-way valve, simpler, to overcome at least some of these disadvantages.

Thus, the invention relates to a three-way valve for use in an intake pipe of an internal combustion engine with recirculation of the exhaust gas comprising at least two closure means disposed respectively in two channels of the valve, said closure means being adapted to occupy an open position and a closed position and at least one intermediate position, a first of said closure means being arranged to drive a second of said closure means into one of when the first closing means is driven into one of the closing and opening positions by a drive member, the second closing means is driven with a temporal phase shift relative to when driving the first closure means.

The phase shift, when opening or closing the channels of the valve 25 allows to accurately set the degrees of opening of the channels over time and thus optimize the performance of the engine.

It will be noted that the term "intermediate position" designates for the closure means a stable position that can be occupied in a discrete manner. This is not a position through which the closure means would pass continuously.

Preferably, the first closure means is driven with a temporal phase shift relative to the driving of the drive member. Preferably, a closing means comprises a guide pin and a toothed wheel with a driving groove, the guide finger being inserted into the driving groove.

The cooperation of a guide finger and a drive groove advantageously makes it possible to parameterize the duration of the phase shift of said closing means. More preferably, a closure means comprises a closure head and a closure seat, the head being arranged to cooperate with the seat to close the valve channel in which said closure means is disposed.

Still preferably, another closure means comprises a shutter in the valve path in which is disposed said other closure means.

Preferably, said closing means comprises a valve stem, a drive cam and a disengagement cam, the disengagement cam being connected externally and coaxially to the drive cam, the drive cam being externally and coaxially connected to the valve stem.

Advantageously, the valve stem has radial drive arms protruding out of the drive grooves and disengagement grooves formed respectively in the drive cam and the disengagement cam.

The combination of the radial drive arms with drive grooves and disengagement grooves makes it possible to parameterize the phase shift of said closure means by controlling its speed and its degree of opening.

The invention will be better understood with the aid of the following description of several embodiments of the valve of the invention with reference to the appended drawing in which:

FIG. 1 shows a perspective view of a first embodiment of the three-way valve of the invention; - Figure 2 shows a top view of the valve of Figure 1; Figure 3 shows another perspective view of the valve of Figure 1; FIG. 4 represents a linear development view of the position of the radial drive arm in the disengagement and drive grooves; FIG. 5 is a perspective view of a second embodiment of the 3-way valve of FIG. the invention; FIG. 6 represents an exploded view of a means for closing the valve of FIG. 5; and FIG. 7 represents a view from above of the valve of FIG. 5. Referring to FIG. 1, the three-way valve 10 comprises two input channels 1, 2 and an output channel 3. The two channels 1, 2 are closed respectively by a shutter 121 and a shutter 131 forming a valve resting on a seat 132 disposed in the path 2. By internal or external, or inside or outside, will be heard, in the description, internal or external, or inner or outer, to a shaft or rod, radially, relative to its axis.

The shutter shutter 121 is connected to a rotary shaft 122 mounted in the track 1 along an axis X1. The surface of the shutter shutter 121 corresponds to the section of the track 1 in which the shutter 121 is disposed. Thus, in the closed position, no fluid can cross the way 1.

The shaft 122 is terminated, at its upper end, by a transverse portion 123 of which two guide fingers 124A and 124B extend parallel to the shaft 122. The shaft 122 is fixed between the guide fingers 124A and 124B, in the center of the transverse portion 123.

With reference to FIG. 2, the shutter 121 is rotated by a gear 125 via guide fingers 124A, 124B. The gear 125 includes drive grooves 125A, 125B forming portions of circular arcs in the central portion of the wheel 125. The gear wheel 125 is pierced at its center by a through hole 126 into which the rotary shaft 122, the guide fingers 124A, 124B, is inserted. respectively in the drive grooves 125A, 125B of the toothed wheel 125. Referring to FIG. 3, stop pieces 127, 128 are arranged to block the rotation of the end of the guide pin 124B and thus keep the shutter 121 in the open or closed position. The stop parts 127, 128 are here fixed elements belonging to the vehicle casing.

A helical return spring 129 makes it possible to elastically return the shutter flap 121 in the open position after it has been rotated. The coil spring 129, fixed on the rotary shaft 122, has its two ends fixed to the stop pieces 127, 128.

The gear wheel 125 is driven by a drive gear 165 which will be presented later. When rotating the wheel 125 about its axis, the flap 121 can be rotated by the shaft 122 according to the position of the guide fingers 124A, 124B in the drive grooves 125A, 125B.

In order to explain the different closing phases of the shutter flap 121, reference is made to FIG. 2, which represents the shutter flap 121 in the open position. The guide fingers 124A, 124B are in an abutment position in the hour ends of the drive grooves 125A, 125B of the toothed wheel 125. The transverse portion 123 is aligned parallel to the axis of the track 1, the shutter shutter 121 being in the open position.

The term "clockwise end" of a groove of a disc, the end with which a finger abuts when it travels the groove in the clockwise direction relative to the axis of the disc. Similarly, the term trigonometric end, the end with which a finger abuts when it travels the groove in the counterclockwise direction, which is the opposite direction of clockwise.

When the gearwheel 125 is rotated in the clockwise direction about the axis X1, the drive grooves 125A, 125B are free to rotate about the axis X1 without transmitting power to the shaft 122, the fingers in the grooves 125A, 125B relative to the wheel 125. The gear 125 is rotated while the shutter 121 remains in the open position. The closure of the channel 1 is thus performed with a temporal phase shift.

The gearwheel 125 continues to rotate in a clockwise direction until the trigonometric ends of the grooves 125A, 125B engage the guide fingers 124A, 124B, which are then abutted with the grooves 125A, 125B . The gear wheel 125 transmits the rotational movement to the shutter 121 through the rotary shaft 122 and guide fingers 124A, 124B.

With reference to FIG. 1, the return spring 129 twists, to be wound, as the shaft 122 is rotated clockwise, the force exerted by the wheel 125 preventing the spring 129 to unfold.

Thus, during the rotation of the driving wheel 165, the shutter 121 closes with a certain phase shift. The length of the arc portions of the drive grooves 125A, 125B makes it possible to define the duration of the phase shift and to parameterize the valve 10 according to its mode of use.

When the guide pin 124B is stopped by the stop piece 127, the closed position of the shutter 121 is reached. If the wheel 125 continues to rotate in a clockwise direction, the shutter 121 remains held in the closed position. However, if the wheel 125 is no longer driven, the return spring 129 unwinds and drives the shaft 122 in a counter-clockwise rotation, the shutter 121 being then in the open position.

Referring to Figure 3, the channel 2 of the three-way valve 10 is closed by a closure means in the form of a closure head 131 forming a valve resting on a seat 132 disposed in the channel 2. The shutter head 131 is mounted on a valve stem 130 extending along an axis X2. The valve stem 130 translates along its axis in the track 2 in order to match the closure head 131 with the seat 132.

Referring to FIGS. 1 and 3, the valve stem 130 is terminated at its upper end by two radial drive arms 133A, 133B diametrically opposed and orthogonal to the axis X2, the arms 133A, 133B forming with the rod 130 T. The two radial drive arms 133A, 133B are terminated at their ends by two locking shoulders 134A, 134B which can be seen in FIG. 2. The radial drive arms 133A, 133B pass successively through a cam 160 of the valve and a cam 170 disengaging the valve. With reference to FIG. 1, the cam 170 is shown in transparency to distinguish the passage of the arm 133A in the drive cam 160 disposed within the disengagement cam 170. The valve drive cam 160 is in the form of a cylinder extending coaxially and externally to the valve stem 130, the drive cam 160 extending coaxially and internally to the disengagement cam 170. The cam 160 for driving the valve comprises two diametrically opposed grooves 161A, 161B for driving, formed in its transverse envelope, out of which the radial drive arms 133A, 133B project respectively.

With reference to FIG. 4, the driving groove 161A is in the form of an L in linear development, the radial drive arms 133A, 133B thus being able to translate into the cam 160 for driving the valve according to a horizontal portion and a vertical portion.

The drive cam 160 is connected to the toothed wheel 165 by a cylindrical motion transmission member 162, extending coaxially with the valve stem 130 along the axis X2. The rotation of the gear wheel 165 is transmitted to the drive cam 160 to move the drive grooves 161A, 161B and to change the position of the radial drive arms 133A, 133B. The toothed wheel 165 is here driven for a not shown drive member such as an electric motor.

A return means 139 resiliently removes the sealing head 121 in the open position after the valve stem 130 has been rotated. The means 139 is here a helical spring 139 fixed on the cylindrical motion transmission element 162, the two ends of the spring being fixed to the motor casing.

In order to allow raising and lowering of the valve stem 130 in the track 2, a valve disengagement cam 170 is associated with the drive cam 160. The valve disengagement cam 170 is in the form of a cylinder extending coaxially and externally to the drive cam 160. Disengagement grooves 171A, 171B are formed in the cylindrical casing of the cam 170. Disengagement grooves 171A, 171B having the shape of a helix portion as shown in Figure 3. Referring to Figure 4, the disengagement groove 171A is in the form of a curve portion in linear development.

The radial drive arms 133A, 133B successively pass through the drive grooves 161A, 161B and the disengagement grooves 171A, 171B, through which the locking shoulders 134A, 134B of the radial drive arms 133A, 133B project respectively, the locking shoulders 134A, 134B guiding and holding the radial arms 133A, 133B in the grooves.

Disengagement cam 170 is here fixedly connected to the internal casing of the vehicle engine.

In order to explain the different closing phases of the channel 2, reference is made to FIG. 2 showing the shutter head 131 in the open position and FIG. 4 representing the position of the arm 133A in the grooves 161A and 171A. .

The radial drive arms 133A, 133B are located at the horizontal trigonometric ends of the Ls formed by the drive grooves 161A, 161B and at the lower ends of the helical grooves 171A, 171B of the disengagement cam 170. The sealing head 131 is here in the low position which allows the passage of fluid in the channel 2 as shown in Figure 3.

During rotation of the gearwheel 165 clockwise about the axis X2, the drive grooves 161A, 161B are rotated until the radial drive arms 133A, 133B enter respectively in abutment with the bases of the L, that is to say the intersection of the vertical and horizontal portions of the drive groove 161A, 161B. During the translation of the radial drive arms 133A, 133B into the horizontal portion of the drive grooves 161A, 161B, these remain at the lower end of the disengagement grooves 171A, 171B, the track 2 thus remaining opened.

The gear wheel 165 continues to rotate clockwise, the cam 170 forcing the radial drive arms 133A, 133B to translate vertically in the drive grooves 161A, 161B rotating about the axis X2. The helical ascending of the radial drive arms 133A, 133B is guided by the disengagement grooves 171A, 171B as shown in FIG. 4, the radial arms 133A, 133B performing the same function as guide fingers.

The shape of the disengagement grooves 171A, 171B advantageously makes it possible to parameterize the ascending speed of the valve stem 130, the degree of opening of the channel 2 being able to be controlled also.

The spring 139 twists as the radial arms 133A, 133B rotate, the rotation of the wheel 165 preventing the unwinding of the spring 139. When the radial arms 133A, 133B reach the vertical ends of the driving grooves 161A 161B and the upper ends of the disengagement grooves 171A, 171B, the valve head 131 rests on the seat 132, the channel 2 is then completely closed. The combination of drive grooves 161A, 161B and disengagement 171A, 171B makes it possible to control the opening of the track 2 and to define the duration of the phase shift with respect to the rotation of the wheel 165, the horizontal portion of the grooves d the drive 161A, 161B advantageously defining the phase shift duration.

As previously described, the toothed wheel 165 meshes with the toothed wheel 125 to control the opening of the track 1. Each of the tracks is closed or opened with a temporal phase shift whose duration is parameterizable. The engine performance is thus optimized, both at the intake and at the exhaust.

In another embodiment of the invention, with reference to FIG. 5, the channels 1, 2 of the three-way valve 20 are closed respectively by closure shutters 221, 321. The shutter flaps 221, 321 are respectively connected to rotary shafts 222, 322 extending along X200 and X300 axes. The surfaces of the shutters 221, 321 correspond to the sections of the tracks 1, 2 in which the flaps 221, 321 are respectively arranged.

Referring to Figure 6, the rotary shafts 222, 322 are inserted successively into disengaging disks 260, 360, in gears 250, 350 and guide members 230, 330 respectively. The rotary shafts 222, 322 are respectively terminated at their upper ends by locking members 291, 391 for holding together the various elements traversed by the shafts 222, 322.

With reference to FIG. 6, the disengaging discs 260, 360 are respectively pierced with central holes 262, 362 and respectively comprise grooves 261, 361. The grooves 261, 361 have substantially an arc shape whose end trigonometric device forms an oblique disengagement notch 261A, 361A. The disengagement disks 260, 360 are fixedly held in the internal casing of the motor.

The toothed wheels 250, 350 are respectively pierced with central holes 252, 352 and comprise grooves 251, 351. The grooves 251, 351 have substantially a circular arc shape whose trigonometric end forms a radial translation notch 251A, 351A. The gears 250, 350 are respectively movable about the axes X200 and X300.

The guide members 230, 330 comprise radial drive grooves 231, 331 and guide fingers 235, 335 respectively. A guide member 230, 330 is in the form of an arm whose radial drive groove traverses substantially over its entire length, the guide pin being fixed orthogonally to a longitudinal end of the arm.

The shafts 222, 322 pass respectively through the radial drive grooves 231, 331 of the guide members 230, 330, the guide members 230, 330 being respectively fixed to the ends of the shafts 222, 232 by locking members 291, 391. The locking members 291, 391se are in the form of a cylinder in which is formed a diametrical locking groove corresponding to the narrowing section of the upper ends of the shafts 222, 232. The narrowing section of the shaft 222, 322 s threads into the locking groove to hold together the various elements traversed by the shaft 222, 322 as shown in FIG.

In order to explain the different closing phases of the track 2, reference is made to FIG. 7 showing the closing means of the track 2 in the closed position.

With reference to FIG. 7, when the toothed wheel 350 is rotated in the clockwise direction about the X300 axis by a not shown drive member, the guide pin 335 moves in the grooves 351, 361, 10 relative to the toothed wheel 350. Still referring to FIG. 7, in a closed position of the track 2, the guide pin 335 is located at the hour end of the driving groove 351, in the radial notch 351A, and at the trigonometric end of the release groove 361.

During the rotation of the toothed wheel 350 in the clockwise direction, the guide pin 335, abutting in the radial notch 351A, is rotated by the drive groove 351, the guide pin 335 transmitting its movement. rotation to the shutter 321 which passes from a closed position to an open position. The opening of the shutter 321 is progressive, the guide pin 335 sliding in the arcuate portion of the groove 361 until reaching the oblique notch 361A, located at the clockwise end of the groove 361. In the oblique portion 361A of the groove, the guide pin 335 is moved away from the axis of rotation which causes a translation of the guide member 330 with respect to the shaft 322 in the guide groove 331, until the guide pin 335 abuts in the hour end of the oblique notch 361A. The opening of the channel 2 is then complete.

The guide pin 335 is then no longer in abutment position in the radial notch 351. The rotation of the toothed wheel 350 is continued, the guide pin 335 traversing the arc portion of the groove 351 in the groove 351. the direction trigonometric relative to the disengagement wheel 360. The channel 2 remains open despite the rotation of the toothed wheel 350. There is a phase shift between the drive means and the closure means.

It goes without saying that the phase shift could also occur before the opening of the track. It would suffice to drive the wheel 350 in rotation in the opposite direction.

The closure / opening mechanism of the closure means of the channel 1 is similar to that previously described.

The combination of the two closure means provided with their phase shift means makes it possible to coordinate the respective opening of the channels 1, 2. The three-way valve, as shown, makes it possible to optimize the performance of the motor 10 by adjusting the phase shift and the degree of opening of the different channels.

Claims (12)

claims A three-way valve for use in an intake pipe of an internal combustion engine with exhaust gas recirculation comprising at least two closure means disposed in two lanes (1, 2) of the valve (10, 20), said closure means being able to occupy an open position and a closed position as well as at least one intermediate position, a first of said closure means being arranged to drive a second said closing means in one of the closing and opening positions, the first closing means being driven into one of the closing and opening positions by a drive member, the second closing means is driven with a temporal phase shift with respect to the driving of the first closure means. 2. Valve according to claim 1, wherein the first closure means is driven with a temporal phase shift relative to the driving of the drive member. 3. Valve according to one of claims 1 to 2, wherein one of the closing means comprises a return means (129, 139) arranged to return said closure means in a rest position after being driven. 4. Valve according to one of claims 1 to 3, wherein a closing means comprises a guide pin (124A, 124B, 133A, 133B, 235, 335) and a toothed drive wheel (125, 165, 250 , 350) with a drive groove (251, 261), the guide pin (124A, 124B, 133A, 133B, 235, 335) being inserted into the drive groove (251, 261). 5. Valve according to one of claims 1 to 4, wherein said closure means comprises a closure head (131) and a closure seat (132), the head (131) being arranged to cooperate with the seat (132) to close the valve channel in which said closure means is disposed. The valve of one of claims 1 to 5, wherein said closure means comprises a valve stem (130), a cam (160) for driving and a cam (170) for disengaging, the cam (170) of disengagement being externally and coaxially connected to the drive cam (160), the drive cam (160) being externally and coaxially connected to the valve stem (130). The valve of claim 6, wherein the valve stem (130) has radial drive arms (133A, 133B) projecting from the driving grooves (161) and disengagement grooves (171) formed therein. respectively in the drive cam (160) and the disengagement cam (170). Valve according to claim 7, wherein the driving grooves (161) are L-shaped. 9. Valve according to claim 4, wherein another closure means comprises a shutter (121) in the path of the valve in which is disposed said other closure means. 10. A valve according to claim 9, wherein said other closure means comprises a disengaging disk (260) in which a disengaging groove (261) is formed. The valve of claim 10, wherein the drive (251, 351) and disengagement (261, 361) grooves respectively comprise a radial translation notch (251A, 351A) and a notch (261A, 361A) of oblique clearance. 12. A valve according to claim 9, wherein stop members (127, 128) of the motor housing are arranged to lock the rotation of the guide pin (124B).