EP2245349B1 - Two-shutter three-way valve - Google Patents

Description

The invention relates to a three-way valve with two flaps and this invention arises from an EGR loop problem of an internal combustion engine of a motor vehicle, comprising, with reference to the figure 7 in the appendix, the engine 21, an exhaust manifold 22 for the combustion gases, a turbine 25 for a turbo-compressor 24, the exhaust gas recirculation loop (EGR) 28, with a cooler 29 and the three-way valve 30 low pressure disposed upstream of the compressor 26 of the turbo-compressor 24 and connected to it by its output and having two inputs for receiving fresh air and the cooled exhaust gas, a mixture whose pressure is increased in the compressor 26, and an intake manifold 23 of the engine for receiving the exhaust gas and the compressor air.

The patent application US 2005/0241702 A1 has a valve according to the preamble of claim 1.

The three-way valve could also be arranged on the cold side of the engine, with an inlet downstream of the compressor of the turbo-compressor, and two outputs respectively connected to the exhaust and the cooler of the EGR loop.

The EGR loop aims to reduce the emission of nitrogen dioxide, by reducing the combustion temperature, by slowing down the combustion of the combustion mixture and absorbing part of the calories. The cooler of the EGR loop makes it possible to lower the combustion temperature at high speed (high load).

• Le débit de l'air frais dans la voie d'arrivée de l'air de la vanne EGR étant maximum,
• on ouvre progressivement la voie des gaz EGR dans la vanne et,
• avant que le débit des gaz EGR dans la vanne n'augmente plus,
• on ferme progressivement la voie d'arrivée de l'air frais pour continuer de faire croître le débit des gaz EGR, suivant une courbe monotone croissante.

To return to the three-way valve arranged on the side of the intake manifold, on the cold side, several operating modes of the three-way valve and therefore of the engine can be envisaged. The engine may only receive fresh air with no recirculated exhaust. The engine can receive fresh air mixed with a portion of the exhaust gas, the pressure difference between the exhaust and the intake of the engine being sufficient to ensure the recirculation of the exhaust gas. When the pressure difference is not sufficient for gas recirculation exhaust system and to ensure the correct EGR rate, it can create a throttling against pressure of the exhaust path downstream of the EGR loop, thereby forcing a portion of the exhaust gas to the intake path of the engine. This solution, by its complexity, however, is not very satisfactory and it is preferable to use the EGR loop as follows.

• The fresh air flow rate in the EGR air intake channel is maximum,
• the EGR gas channel is gradually opened in the valve and,
• before the flow of EGR gas in the valve increases,
• the fresh air inlet is gradually closed to continue to increase the flow of the EGR gas, following a monotonous curve increasing.

The invention of the present concerns first, but not exclusively, a tri-way valve with two flaps to be able to use the EGR loop as defined above and which is of a good price and a footprint as small as possible . Naturally, the Applicant does not intend to limit the application of the valve of the invention to the use developed above of the EGR loop and therefore his invention will generally concern any three-way valve two shutters that must be operated with a temporal phase shift. In this case, the one mentioned above, the two flaps are arranged in the two input channels of the valve, in the other, in the two output channels.

Thus, the invention relates to a three-way valve with two flaps respectively arranged in two of the three channels of the valve comprising means for controlling and actuating the flaps to cause them to pivot from one to the other of two positions. opening and closing of the tracks, characterized in that there are provided single control means for the two flaps and actuating means arranged to be controlled by the single control means and to actuate the two flaps with a temporal phase shift.

• les moyens d'actionnement comprennent une cinématique d'engrenages attaquée par un pignon dentée de l'arbre du moteur de commande et qui engrène avec une roue dentée cylindrique intermédiaire à deux dentures coaxiales, respectivement de rapports d'engrenage différents,
• la roue intermédiaire coopère avec deux couronnes dentées solidaires en rotation des deux volets.

Preferably, the control means comprise a DC motor,

• the actuating means comprise gear kinematics driven by a toothed pinion of the control motor shaft and which meshes with an intermediate cylindrical gearwheel with two coaxial teeth, respectively of different gear ratios,
• the intermediate wheel cooperates with two integral toothed crowns in rotation of the two flaps.

In the preferred embodiment of the valve of the invention, the flaps are arranged in its two inlet channels, the valve then being a cold-side EGR loop valve, connected to the intake manifold of a combustion engine. internal combustion of a motor vehicle.

• les figures 1a, 1b, 1c, 1d illustrent les quatre modes d'utilisation de la vanne trois voies de la boucle EGR dont l'utilisation particulière et décrite ci-après ;
• les figures 2a, 2b, 2c représentent les courbes de débit d'air (1a), de débit naturel de gaz d'échappement EGR (dgn) et de débit, forcé selon le procédé d'utilisation, de gaz d'échappement EGR (dgf), en fonction des positions angulaires (α) des volets correspondants ;
• la figure 3 est une vue en perspective de la cinématique d'une vanne trois voies à deux volets, selon l'invention, volet d'air ouvert et volet des gaz fermé ;
• la figure 4 est une vue de la vanne de la figure 3, volet des gaz en position d'ouverture partielle ;
• la figure 5 est une vue de la vanne de la figure 3, volet des gaz ouvert et volet d'air fermé ;
• la figure 6 est une vue partielle en perspective de la cinématique d'une vanne trois voies selon une variante du mécanisme de déphasage temporel de la fermeture du volet d'air par rapport à l'ouverture du volet des gaz et
• la figure 7 représente de façon simplifiée, la boucle EGR utilisée selon le mode illustré sur la figure 1.

The invention will be better understood with the aid of the following description of a mode of use of the three-way valve of the invention as well as of the three-way valve itself, with reference to the drawing in the appendix, on which

• the Figures 1a, 1b, 1c, 1d illustrate the four modes of use of the three-way valve of the EGR loop, the particular use of which is described below;
• the Figures 2a, 2b, 2c represent the curves of air flow (1a), natural flow of exhaust gas EGR (dgn) and flow, forced according to the method of use, exhaust gas EGR (dgf), depending on the positions angular (α) corresponding flaps;
• the figure 3 is a perspective view of the kinematics of a three-way valve with two flaps, according to the invention, open air flap and closed flap gas;
• the figure 4 is a view of the valve of the figure 3 , flap of gases in partial open position;
• the figure 5 is a view of the valve of the figure 3 , open gas shutter and closed air shutter;
• the figure 6 is a partial perspective view of the kinematics of a three-way valve according to a variant of the temporal phase-shift mechanism of the closure of the air shutter with respect to the opening of the flap of the gases and
• the figure 7 represents, in a simplified way, the EGR loop used according to the mode illustrated in FIG. figure 1 .

The EGR valve 1 of Figures 1a, 1b, 1c , schematically, comprises an air inlet 2, a recirculated exhaust gas inlet 3 and an air and gas outlet 4.

The valve 1 is here a two-part valve, a flap 5 in the air inlet duct 2 and a flap 6 in the gas inlet duct 3.

Firstly, the air flap 5 is in an angular position (0 °) allowing a maximum air flow in the track 2 and the arrival flap of the gases 6, in an angular position (90 °) shutting off way 3.

Then, without the air flap 5 being rotated, the gas inlet flap 6 begins to pivot to progressively open the track 3 to the exhaust gas EGR ( figure 1a ). This is the zone 1 of the curves 2. Then, the air flap 5 remaining in the same position of maximum opening of the air inlet 3, the flap of the gas 6 pivots to considerably open the way of gas 6 ( figure 1b ). This is the zone II of the curves 2. In a certain angular position of the flap of the gases 6, here 35 °, that is to say after a rotation of 55 °, the flow of the gases in the way 3 does not increase substantially and, while continuing to rotate the flap of the gas 6, then starts to rotate the air flap 5 to close the air inlet duct 2, with a corresponding phase shift, and thus, force the engine to draw more EGR gas ( figure 1c ).

Enter Zone III curves 2, the exhaust flow curve bending to continue to rise.

This zone III extends until the gas flap 6 reaches the angular position 0 ° maximum opening of the gas inlet channel 3 and the air flap is in the angular position (90 °) shutting the air inlet 2.

For the implementation of the supply of the three-way EGR valve 1, as defined above, this three-way valve has the kinematics which will now be described with reference to the Figures 3 to 5 .

The kinematics of the three-way valve 1 comprises a gear extending, here, between a DC motor 7 and two shafts 51, 61 for rotating the air flap 5 and the gas flap 6, respectively. The two shafts 51, 61 extend parallel to each other.

The shaft 14 of the motor 7 is secured to a pinion 8 for driving an intermediate toothed wheel 9 bearing a peripheral toothing 10 and a central toothing 11.

The peripheral toothing 10 of the intermediate wheel meshes with a ring gear 12 for rotating the air flap 5. The ring gear 12 is free to rotate relative to the axis 51 of the flap 5. The rotational drive this flap 5 by the ring 12 is via a drive finger 15 which is itself integral in rotation with the axis 51 of the flap 5. This finger 15 is disposed at rest against an adjustable stop 16 integral with the body of the valve (not shown). The ring 12 has an angular notch 17 adapted to allow the free rotation of the ring 12 on a defined angular sector, without driving the finger 15, that is to say the flap 5. It is when the ring 12 is driven in rotation beyond this angular sector, in one direction or the other, that the edge of the notch 17 then drives the finger 15.

The central toothing 11 of the intermediate wheel 9 meshes with a ring gear 13 driving in rotation of the flap of the gases 6: The ring gear 13 is integral in rotation with the axis 61 of the flap 6.

The flap 6 is therefore rotated directly by the rotation of the ring 13, while the flap 5 is rotated only when the ring 12 rotates the finger 15.

In the example, the motor 7, by its pinion 8, rotated in the counterclockwise direction, drives the intermediate wheel 9 in rotation in the direction of clockwise. In turn, the wheel 9, by its teeth 10, 11 drives, in the opposite direction of the needles, the two toothed rings 12, 13, which are thus rotated by the same intermediate wheel 9, but via two gear teeth 10, 11. The gear ratio between the shaft 14 of the motor 7 and the flap of the gas 6 is here 15.67, the ratio between the shaft 14 and the air flap 5 when is driven being 6.67.

The phase shift mechanism of the closure of the air shutter 5 will now be described.

The Figures 3, 4 , and 5 show the crowns and toothed wheels at different stages of rotation of the pinion 8.

Of the figure 3 to the figure 4 , the rings 12 and 13 are driven in the opposite direction of the clockwise causing the opening of the flap 6 while the flap 5 remains stationary and thanks to the angular notch 17. On the position of the figure 4 , one of the edges of this notch 17 comes into contact with the finger 15.

The rotation of the ring 12 then continues towards the position shown figure 5 , the finger 15 (and therefore the flap 5) then being rotated. The shutter 5 thus closes with a temporal phase shift allowed by the notch 17.

An alternative embodiment of the phase shift mechanism is shown in FIG. figure 6 . According to this variant, a cross member 50 with two radial arms 52, 53 is mounted on the shaft 51 of the flap 5. Each of the arms 52, 53 comprises at its end a driving pin 54, 55, extending substantially parallel to the tree 51.

In the ring gear 12 are formed two circular lights 56, 57 for driving fingers 54, 55 in circular translation. The fingers 54, 55 extend respectively in these two lights 56, 57.

As long as the fingers 54, 55 are not resting against one of the bottoms 58 of the slots 56, 57, the shaft 51 and the air shutter 5 can not be rotated. As soon as the fingers 54, 55 abut against the respective bottoms of the two lights 56, 57, the ring gear 12 drives them with it, causing the flap 5 to rotate.

To ensure the correct operation of the three-way valve, the angular opening of the lights must be less than 180 °. If α _g is the angle of rotation of the gas flap 6, α _a , the angle of rotation of the air flap 5, the relation (1) must be satisfied. $$\left({\mathrm{\alpha }}_{\mathrm{boy\; Wut}}-{\mathrm{\alpha }}_{\mathrm{at}}\right)\times \frac{{\mathrm{\alpha }}_{\mathrm{boy\; Wut}}}{{\mathrm{\alpha }}_{\mathrm{at}}}<\mathrm{180}$$

If we consider α _g = 90 ° ( figure 2b ), then the angle of rotation α _a of the air flap 5 must satisfy the relation (2) $${\mathrm{\alpha }}_{\mathrm{at}}>30°$$

doit alors satisfaire la relation (3) $$\mathrm{R}<3$$

The gear ratio $\mathrm{R}=\frac{\alpha \mathrm{boy\; Wut}}{\alpha \mathrm{at}}$

must then satisfy the relationship (3) $$\mathrm{R}<3$$

In the example mentioned above, we considered $$\mathrm{R}=\frac{15,67}{6,67}=2,35$$

The circular lights 56, 57 are formed in the ring 12 relative to the toothed sector of the ring 12 taking into account the amplitude of the angular rotation of the gas flap 6 before the air flap 5 begins to rotate.

The valve that has just been described is remarkable for its uniqueness of control, at the single level of the DC motor 7, which makes it a better price and a smaller footprint.

This control can be performed using an H bridge, well known to those skilled in the art, with two pairs of switches in series and the component to be controlled - here the motor - connected to the two midpoints of the two pairs of switches, the two pairs being connected between a battery voltage and ground.

Claims (6)

1. Three-way valve (1) with two flaps (5, 6) respectively positioned in two of the three paths (2, 3) of the valve and comprising means (7-12) for controlling and actuating the flaps (5, 6) to make them pivot from one to the other of two positions in which the paths (2, 3) are either open or closed, characterized in that single control means (7) are provided for both flaps (5, 6), and there are actuating means (9-12) designed to be controlled by the single control means (7, 8) and to actuate the two flaps (5, 6) with a temporal phase shift, so that by continuing to make the second flap (6) pivot, the first flap (5) is made to start to pivot in order to close the corresponding path (2).
2. Three-way valve according to Claim 1, in which the control means comprise a dc motor (7).
3. Three-way valve according to Claim 2, in which the actuating means comprise a drivetrain (9-12) the input to which comes from a toothed pinion (8) of the shaft of the control motor (7) and which meshes with an intermediate cylindrical gearwheel (9) with two coaxial tooth set (10, 11).
4. Three-way valve according to Claim 1, in which the intermediate gear (9) collaborates with two annulus gears (12, 13) that rotate as one with the two flaps (5, 6).
5. Three-way valve according to one of Claims 1 to 4, in which the flaps (5, 6) are positioned in its two inlet paths (2, 3), the valve then being an EGR loop valve for the cold side, connected to the intake manifold of a motor vehicle internal combustion engine.
6. Three-way valve according to Claim 5, in which the temporal phase shift used by the actuating means is designed to prevent the flow rate of EGR gases from increasing further and to thus force the engine to take in more EGR gas.

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