EP3186496A1

EP3186496A1 - Assembly for an air circuit of a heat engine

Info

Publication number: EP3186496A1
Application number: EP15763053.4A
Authority: EP
Inventors: Nicolas Martin
Original assignee: Valeo Systemes de Controle Moteur SAS
Current assignee: Valeo Systemes de Controle Moteur SAS
Priority date: 2014-08-28
Filing date: 2015-08-26
Publication date: 2017-07-05
Anticipated expiration: 2035-08-26
Also published as: FR3025245A1; CN107076011A; US10400665B2; US20170254258A1; EP3186496B1; WO2016030628A1; FR3025245B1

Abstract

The invention relates to a fluid assembly (1) comprising: a first pipe (11), a second pipe (12) forming a bypass of a portion of the first pipe (11), comprising a compressor (15), and a switching system (10) for switching the fluid into either the second pipe (12) or said portion, having a first configuration allowing the fluid to circulate in the portion, and comprising a supporting member exerting a torque configured to keep the system (10) in the first configuration, and at least one area blocking the inlet or the outlet of the second pipe when the system (10) is in the first configuration, the system (10) being able to enter a second configuration allowing the fluid to circulate in the second pipe (12), the supporting member being such that the torque that it exerts on the system (10) drops when the system (10) passes from the first configuration to the second configuration.

Description

Set for a thermal engine air circuit

The present invention relates to an assembly for a heat engine air circuit.

The invention applies in particular, but not exclusively, in the field of the automobile, the heat engine then allowing to propel the vehicle.

The assembly comprises a first conduit and a second conduit forming a bypass of a portion of the first conduit, the first and second conduits being adapted to be traversed by a fluid. The assembly also comprises a fluid switching system for varying the distribution of the fluid between the portion of the first pipe and the second pipe.

It is known to provide the switching system with an actuator for varying the distribution of the fluid between the portion of the first pipe and the second pipe. Such an actuator, however, has a cost and requires a suitable control law.

The invention aims to overcome this disadvantage while ensuring the desired distribution of fluid between the portion of the first pipe and the second pipe.

The invention achieves this, in one of its aspects, with the aid of an assembly for a heat engine air circuit, comprising:

a first pipe capable of conveying fluid,

a second pipe extending between an inlet in the first pipe and an outlet in the first pipe, so as to form a bypass of a portion of the first pipe, the second pipe comprising a pressure variation source, and

a system for routing the fluid in one of the second pipe and in said portion of the first pipe, the switching system having a first configuration allowing the fluid to circulate predominantly in said portion of the first pipe, the system referral system comprising:

a holding member exerting a torque configured to bring or maintain said switching system in the first configuration, and

at least one of an area closing in this first configuration all or part of the inlet of the second pipe, and an area closing in this first configuration all or part of the output of the second pipe,

the switching system being arranged to pass into a second configuration allowing the fluid to circulate mainly in the second pipe when the pressure variation generated in the second pipe by the source exceeds a predefined value, this pressure variation then exerting on the said zones of the referral system a torque allowing this passage in the second configuration, despite the torque exerted by the holding member, the holding member being such that the torque exerted on the switching system decreases when the switching system passes from the first to the second configuration.

The invention allows the total torque, consisting of the torque exerted by the pressure variation source to which is added the torque exerted by the holding member, is strictly positive when the switching system passes from the first to the second. configuration. It is thus possible to compensate for the effect of the decrease in the torque exerted by the source as the switching system from the first to the second configuration passes.

The switching system may be arranged to go from the first configuration in the second configuration or the second configuration in the first configuration only by the action of the holding member and / or the source of pressure variation.

The assembly may be devoid of an actuator dedicated to the passage of the switching system from the first to the second configuration.

The above set takes advantage of the presence in the second conduit of the pressure variation source to change the configuration of the switching system. Thanks to the zone or zones closing in the first configuration at least partly the inlet of the second pipe and / or at least partly the output of the second pipe, this pressure variation is capable of generating a torque on the pipe system. switching, allowing to modify the configuration of the latter. The invention thus allows the pressure variation source to act as an actuator causing the switching system to pass from the first to the second configuration, instead of an actuator dedicated to this passage and comprising for example an axis moving the referral system.

The pressure variation source may be an electric supercharger disposed in the second conduit.

Such an electric supercharger can quickly supply the engine with compressed air when the engine runs at low speed or a sudden increase in load. This compressor for example seconds then a

turbocharger associated with the engine, to remedy the turbocharger's important response time, also called "turbolag".

The holding member may be selected in accordance with the source of variation of pressure, in order to allow the passage of the switching system in the second configuration from the predefined value of pressure variation generated by the pressure variation source. .

The switching system may comprise at least one pivoting flap when the system passes from the first to the second configuration, and vice versa.

In an exemplary embodiment of the invention, the holding member may comprise a spring and a lever rigidly coupled to the flap, lever through which the pair of maintenance is exerted on the flap, the spring comprising a fixed end and a movable end moving, in particular in translation relative to the lever, when the flap passes from the first in the second configuration, the displacement to vary the lever arm .

The spring may be a compression spring.

The spring may be a tension spring.

The lever may comprise a housing in which can move a pin secured to the movable end of the spring to vary the lever arm.

The holding member may define a path guiding the movement of the pin in the housing so that the lever arm takes a succession of predefined values when the switching system passes from the first to the second configuration.

The holding member may comprise a fixed cam and the path may be a cam path.

The lever can be rigidly coupled to the flap.

The path can define a curvature in eccentric circles.

Alternatively, the path may define a curvature arranged so that the total torque exerted on the flap, consisting of the torque exerted by the pressure variation source to which is added the torque exerted by the holding member, is strictly positive when the switching system goes from the first into the second configuration.

Independently or in combination with the foregoing immediately, the surface of the zone or zones closing at least in part the inlet and / or the outlet of the second pipe may be chosen to allow the passage of the switching system in the second configuration from the predefined value of pressure variation generated by the source of variation of pressure.

In the first configuration of the switching system, said zone can close all of the inlet of the second conduit or the entire output of said second conduit.

In this first configuration, the entire fluid can thus borrow the portion of the first pipe, leaks near in the referral system.

In the second configuration of the switching system, all or part of the fluid can take the second conduit. The term "predominantly" used above should be understood to mean both "more than half the flow rate of the fluid in the first pipe upstream of the inlet of the second pipe" than "the total flow of the fluid in the first pipe upstream of the entrance to the second pipe ".

The first and second lines may be part of the engine intake circuit.

The electric supercharger may be disposed downstream of an exhaust gas recirculation loop (EGR) outlet. The electric supercharger can be arranged upstream, downstream or parallel to the turbocharger compressor.

According to a first variant of the implementation example mentioned above, the pivoting flap of the switching system is disposed at the inlet of the second pipe.

According to this first variant, the inlet and the outlet of the second pipe can be arranged at a distance from one another in the first pipe.

According to this first variant, said shutter has, when the switching system is in the first configuration:

a first part extending in the first pipe, outside the inlet of said second pipe, and

a second part closing all or part of the inlet of the second pipe and defining said zone of the switching system,

so that when a pressure variation corresponding to a vacuum at the inlet of the second pipe and generated by the source exceeds the preset value, this pressure variation causes the flap to pivot in a position in which the first part closes all or part of said portion of the first pipe and wherein the second portion extends into the second pipe while allowing the fluid to flow mainly in the second pipe, according to the second configuration of the switching system.

The shutter can then be sucked into the second pipe due to the pressure variation, changing the distribution of the fluid between the portion of the first pipe and the second pipe.

The section of the first part of the component may be smaller than the section of the second part of the component. Such a ratio between these sections can promote the pivoting of the flap to move from the first configuration in the second configuration as soon as low values of pressure variation are reached in the second pipe.

In the second configuration, the shutter can close the access to the portion of the first pipe, so that all the fluid is directed to the pressure variation source.

According to a second variant of the implementation example mentioned above, the pivoting flap of the switching system is disposed at the outlet of the second pipe.

According to this second variant, the shutter has, when the switching system is in the first configuration, a part closing all or part of the output of the second pipe and defining said zone of the switching system, so that when a pressure variation corresponding to an overpressure at the outlet of the second pipe and generated by the source exceeds the preset value, this pressure variation causes the flap to pivot in a position in which said part closes all or part of said portion of the first pipe, according to the second configuration of the switching system.

The shutter can then be pushed out of a position opposite the outlet of the second pipe because of the variation in pressure, changing the distribution of the fluid between the portion of the first pipe and the second pipe.

The shutter, regardless of the configuration of the routing system, may extend only in the first pipe: next to the output of the second pipe in the first configuration, and remote from this output in the second configuration.

In the second configuration, the flap can close the portion of the first conduit, so that all fluid is directed to the source of pressure variation.

According to this second variant, the shutter may, in a plane perpendicular to its pivot axis, extend only on one side of said axis.

According to this first and second variant, the switching system may thus comprise only one flap to modify the distribution of fluid in the portion of the first pipe and in the second pipe.

According to a third variant of the implementation example mentioned above, the referral system comprises:

a first pivoting flap disposed at the inlet of the second duct, in particular identical to the shutter according to the first embodiment of the invention, and

- A second pivoting flap disposed at the outlet of the second pipe, in particular identical to the flap according to the second example of implementation of the invention.

According to this third variant:

the first component has, when the switching system is in the first configuration, a first part extending in the first conduit, outside the inlet of said second conduit, and a second part closing all or part of the first conduit; entering the second conduit and defining one of said switch system zones,

the second component having, when the switching system is in the first configuration, a part closing all or part of the output of the second conduit and defining another of said zones of the switching system,

so that when a pressure variation corresponding to a vacuum at the inlet of the second pipe and an overpressure at the outlet of the second pipe and generated by the source exceeds the preset value, this pressure variation causes, according to the second configuration of the referral system:

the pivoting of the first flap in a position in which the first part of the first flap closes all or part of said portion of the first duct and in which the second flap part of the first component extends in the second conduit while allowing the fluid to circulate mainly in this second conduit, and

- The pivoting of the second flap in a position in which said portion of the second flap closes all or part of said portion of the first pipe.

According to this third variant, the inlet and the outlet of the second pipe may be completely or partially closed off by separate shutters when the switching system is in the first configuration, whereas two separate shutters placed in series may close at all. or part of the first pipe when the steering system is in the second configuration.

According to this third variant, the holding member may comprise:

a first spring and a first lever rigidly coupled to the first flap, the first lever through which the holding torque is exerted on the first flap, the first spring comprising a fixed end and a moving end moving, in particular in translation by report to said first lever, when the first component passes from the first to the second configuration, the displacement allowing to vary the lever arm, and

a second spring and a second lever rigidly coupled to the second flap, the second lever through which the holding torque is exerted on the second flap, the second spring comprising a fixed end and a movable end moving, in particular in translation by report to said second lever, when the second flap passes from the first into the second configuration, the displacement to vary the lever arm.

In this way, the torque exerted by the holding member on each of the first and second flaps can decrease as the switching system passes from the first to the second configuration.

According to a fourth variant of the implementation example mentioned above, the inlet and the outlet of the second pipe are disposed adjacently in the first pipe, and the pivoting flap of the switching system is disposed at the times at said input and output.

The inlet and outlet of the second conduit may be formed by openings along a straight portion of the first conduit.

According to this fourth variant, a single component replaces the first and second components of the third variant.

According to this fourth variant, said shutter has, when the switching system is in the first configuration:

a second part closing all or part of said input and forming one of said zones of the switching system, and a first part closing all or part of said output and forming another of said zones of the switching system,

so that, when a pressure variation corresponding to an overpressure at the outlet of the second pipe and a vacuum at the inlet of the second pipe and generated by the source exceeds the preset value, this pressure variation causes the pivoting of the shutter in a position in which the first part closes all or part of said portion of the first pipe and in which the second part extends in the second pipe while allowing the fluid to circulate mainly in this second pipe, according to the second configuration of the referral system.

The positioning of this flap promotes its pivoting since the second part is sucked into the second pipe due to the depression at the inlet thereof while the first part is pushed out of a position opposite the exit of the second pipe because of the overpressure prevailing there.

The pivot axis of the flap can separate the first part of the second part of the flap. The ratio between the section of the first part of the flap and the section of the second part of the flap can be greater than one, such a ratio favoring the pivoting of the flap as soon as low values of pressure variation are reached in the second duct.

In all of the above, the fluid may be a gas, such as air, recirculated exhaust gas from the exhaust of the engine, or a mixture of air and recirculated exhaust gas.

In all the above, the electric supercharger may comprise a variable reluctance motor, having for example a nominal power of between 1 and 10 kW, for example 5.5 kW for a rotation speed of 70 000 rpm .

Alternatively, the electric supercharger may comprise a permanent magnet motor.

The set is for example integrated with an automobile.

The invention also relates to a fluid control assembly of a heat engine, comprising:

at least one pipe capable of conveying fluid,

at least one flap disposed in the pipe, the flap being arranged to pass between the first configuration and the second configuration, and

a holding member exerting on said flap, a pair configured to recall or hold the flap in the first configuration,

the holding member being such that the torque it exerts on the flap decreases when the flap passes from the first into the second configuration. In the first configuration, the assembly can be arranged so that the flap defines a maximum passage section for the fluid in the pipe.

In the second configuration, the assembly can be arranged so that the flap defines a minimum passage section for the fluid in the pipe.

Alternatively, in the first configuration, the assembly may be arranged so that the flap defines a minimum passage section for the fluid in the pipe.

In the second configuration, the assembly can be arranged so that the flap defines a maximum passage section for the fluid in the pipe.

In one or other of the above variants, the assembly may comprise a pressure variation source arranged to exert on the flap a torque configured to move the flap into the second configuration when the pressure variation generated. by the source exceeds a predefined value, despite the torque exerted by the holding member.

All the features of the foregoing invention apply separately or in combination with this other aspect of the invention.

The invention will be better understood on reading the following description of non-limiting examples of implementation thereof and on examining the appended drawing in which:

FIGS. 1 and 2 schematically represent an example of an assembly according to the invention, respectively in the first and in the second configuration of the switching system,

FIGS. 3 and 4 schematically represent another example of an assembly according to the invention, respectively in the first and in the second configuration of the switching system, and

FIGS. 5 to 7 show schematically an example of a holding member according to the invention, of at least one of the shutters of the referral system of FIGS. 1 and 2 or of the shutter of the referral system of FIGS. 3 and 4.

FIG. 1 shows an example of an assembly 1 for a heat engine air circuit. This is for example a vehicle engine, operating for example with gasoline or diesel. The assembly 1 is in the example part of the engine intake circuit. It is for example disposed downstream of the outlet in the intake circuit of an exhaust gas recirculation loop (EGR).

The assembly 1 may also be associated with a mechanical compressor forming part of a turbocharger and not shown in the figures.

Set 1 includes:

a first pipe 11 capable of conveying fluid, a second pipe 12 extending between an inlet 13 in the first pipe 11 and an outlet 14 in the first pipe 11.

As shown in FIG. 1, the second pipe thus forms a bypass of a portion 9 of the first pipe 11. Conversely, the portion 9 of the first pipe makes it possible to bypass the second pipe 12.

The second conduit 12 comprises an electric supercharger 15 forming a source of pressure variation. This electric supercharger compressor 15 can assist the turbocharger particularly at low speed or in case of sudden increase in load. This electric supercharger 15 comprises in the example considered a variable reluctance motor.

The first conduit 11 comprises in the example considered a referral system 10 which comprises:

a pivoting flap 16 disposed at the inlet 13 of the second duct 12, and

a pivoting flap 17 disposed at the outlet 14 of the second duct 12.

When the flaps 16, 17 are in the position shown in Figure 1, the switching system 10 is in a configuration hereinafter called "first configuration".

The flap 16 comprises in the example of FIGS. 1 and 2 a first portion 21 and a second portion 22 connected by a pivot axis 40. This pivot axis 40 is located substantially at the junction between the inlet 13 of the second conduit 12 and the first conduit 11, extending opposite said inlet 13.In the first configuration of the switching system 10, the first portion 21 extends into the first conduit 11. The first portion 21 extends for example parallel to the axis along which extends the first pipe at the inlet 13, so that the closure of said first pipe by the first portion 21 is reduced when the switching system 10 is in the first configuration.

The first part 21 further extends out of the second pipe 12 while the second part 22 forms an area 2 of the switching system 10 closing, in the first configuration, the inlet 13 of the second pipe 12. part 22 extends for example in this first configuration opposite the inlet 13 of the second pipe 12 while being in the first pipe 11.

The flap 17 comprises in the example considered a pivot axis 41. As can be seen in FIG. 1, the flap 17 extends, when observed in a plane perpendicular to said pivot axis 41, only one only side of this axis 41. The pivot axis 41 is located substantially at the junction between the outlet 14 of the second pipe 12 and the first pipe 11, facing this outlet 14. In this example, the flap 17 forms a zone 3 of the referral system 10 closing in the first configuration the output 14 of the second conduit 12. The flap 17 is for example opposite said output 14 while extending into the first conduct 11.

In the first configuration of the referral system 10, the fluid flowing in the first pipe 11 upstream of the second pipe 12 flows mainly in the portion 9 of the first pipe 11 bypassing the second pipe 12.

The path then traveled by the fluid is represented by the arrows 50. The term

The "majority" employed above should be understood as meaning "more than half the flow rate of the fluid in the first pipe 11 upstream of the inlet 13 of the second pipe 12".

When leak zones exist at each of the flaps 16, 17 while the switching system 1 is in the first configuration, part of the fluid can thus borrow the second pipe 12.

FIG. 2 shows the assembly 1 of FIG. 1 in a second configuration. In this second configuration, the first portion 21 of the flap 16 closes the portion 9 of the first pipe 11 and the second portion 22 of the flap 16 extends into the second pipe 12 without closing it. Still in this configuration, the shutter 17 closes the portion 9 of the first pipe 11. In this second configuration, the portion 9 of the first pipe is thus doubly closed, on the one hand by the flap 16 near the entrance 13 of the second pipe 12, and secondly by the flap 17 near the outlet 14 of the second pipe 12.

In this second configuration, the fluid flows mainly through the second pipe 12, the first pipe 11 being traversed by the fluid only outside the portion 9. Thus, the fluid is drifted on a portion of the path that he borrowed in Figure 1 and then flows along the path represented by the arrows 51.

Each flap 16, 17 is held or brought into position as shown in Figure 1, by a holding member 72 shown in Figures 5-7 and described below.

As will now be described, the invention allows the configuration of the switching system 10 to be changed from the first configuration described above with reference to FIG. 1 to the second configuration described above with reference to FIG. The passage from the first to the second configuration is obtained without the use of a dedicated actuator to rotate the flaps 16 and 17, in particular without the use of an electric actuator, pneumatic or electromagnetic.

The assembly 1 passes from the first configuration in the second configuration when the electric supercharger 15 generates a pressure variation exceeding one predefined value for supplying compressed air to the heat engine. In this example, this pressure variation corresponds to a vacuum at the inlet 13 of the second pipe 12 and to an overpressure at the outlet 14 of the second pipe 12.

Due to this variation in pressure, a torque is exerted on each flap 16, 17 via the zones 2, 3 of the latter, these zones 2, 3 extending opposite the second pipe when the system referral is in the first configuration.

When the torque exerted on each flap 16 or 17 due to the overpressure generated by the electric supercharging compressor 15 becomes greater than a predefined value which is in the example described greater than the restoring torque exerted on said flap by the control member. corresponding maintenance 72, the latter pivots, so that the switching system 10 is in the second configuration.

The electric supercharger 15 thus plays the role of an actuator causing the passage of flaps 16 and 17 of the first in the second configuration.

When the pressure variation generated by the electric supercharging compressor 15 exerts on each flap 16, 17 a lower torque than the restoring torque exerted by the corresponding holding member 72, the flaps 16 and 17 are returned to the position of the first configuration.

FIG. 3 shows another example of assembly 1 different from that which has just been described with reference to FIGS. 1 and 2 in that:

the inlet 13 and the outlet 14 of the second pipe 12 are disposed adjacently in the first pipe 11, so that the portion 9 is of reduced size, and

- The switching system 10 comprises a single pivoting flap 18 disposed both at the inlet 13 and the outlet 14 of the second pipe 12.

When the flap 18 is in the position shown in Figure 3, the switching system 10 is in the first configuration.

The flap 18 comprises in the example of FIG. 3, a first portion 31 and a second portion 32 connected by a pivot axis 33. This pivot axis 33 is located substantially at the junction between the inlet 13 and the output 14 of the second pipe 12, opposite the inlet 13.

In the first configuration of the switching system 10, the first portion 31 and the second portion 32 extend in the first conduit 11. These first 31 and second 32 portions extend for example parallel to the axis in which s' extends the first pipe 11 at the inlet 13 and outlet 14 of the second pipe 12, so that the closure of the first pipe 11 by these first 31 and second 32 parts is reduced. The first part 31 forms the zone 3 of the referral system 10 closing the outlet 14 of the second conduit 12 while the second part 32 forms in this example the zone 2 of the referral system 10 closing the inlet 13 of the second conduct 12 when the switching system 10 is in the first configuration.

The path then traveled by the fluid is represented by the arrows 60.

FIG. 4 shows the assembly 1 of FIG. 3 in a second configuration. In this second configuration, the first portion 31 of the flap 18 closes the portion 9 of the first pipe 11 and the second portion 32 of the flap 18 extends into the second pipe 12 without closing it.

In this second configuration, the fluid flows mainly through the second pipe 12, the first pipe 11 being traversed by the fluid only outside the portion 9. Thus, the fluid is drifted on a portion of the path that he borrowed in Figure 1 and then flows along the path represented by the arrows 61.

The flap 18 is held or brought into position as shown in Figure 3, by a holding member 72 shown in Figures 5-7 and described below.

As described with reference to FIGS. 1 and 2, the invention makes it possible to change the configuration of the switching system 10 from the first configuration described above with reference to FIG. 3 to the second configuration described above with reference to FIG. FIG. 4. The assembly 1 passes from the first configuration in the second configuration when the electric supercharger 15 generates a variation of pressure to supply compressed air to the heat engine. In this example, this pressure variation corresponds to a vacuum at the inlet 13 of the second pipe 12 and to an overpressure at the outlet 14 of the second pipe 12.

Due to this variation in pressure, a torque is exerted on the flap 18 via the zones 2, 3 of the latter extending opposite the second pipe when the switching system is in the first configuration. This torque allows, as described above the passage of the switching system 10 of the first in the second configuration.

FIGS. 5 to 7 show an example of a holding member 72 of the shutter 18 of the switching system of FIGS. 3 and 4, the shutter 18 being respectively in the first configuration, in an intermediate configuration between the first and the second configuration and in the second configuration. Although described in relation to the assembly 1 of FIGS. 3 and 4, the holding member 72 of FIGS. 5 to 7 is adaptable to any one of the flaps 16, 17 and 18 of the assemblies of FIGS. 1 and 2.

The holding member 72 comprises in the example described, a compression spring70 and a lever 71 rigidly coupled to the flap 18.

The holding member 72 exerts a holding torque on the flap 18 by means of the lever 71.

The compression spring 70 comprises in this example, a fixed end 77 integral with a fixed pin 74 and a movable end 78 integral with a movable pin 75. The fixed pin 74 allows the fixed end 77 to make a movement rotating around it but maintains this fixed end 77 so that no translational movement is possible.

As described below, the mobile pin 75 is movable in translation, in a radial direction relative to the axis of pivoting 33, 40, 41 of rotation of the flap 17, 18. Thus, while moving, it allows the movable end 78 to perform a translation movement relative to the fixed pin 74 and rotation around the movable pin 75.

The lever 71 comprises in this example a housing formed of an oblong hole 76 in which can move a pin 75 integral with the movable end of the spring to vary the lever arm.

The holding member 72 comprises in the example described, a fixed cam 80. This cam 80 comprises a cam track 73 in which the moving pin 75 protrudes. In this example, the cam path 73 defines a curvature in eccentric circles with respect to the pivot axis 33, 40, 41.

Thus, the cam path 73 guides the movement of the movable pin 75 in the housing 76 so that the lever arm takes a succession of predefined values, when the switching system passes from the first to the second configuration. Thus, the movable pin 75 is movable according to a compound movement due to the displacement of the latter in the cam path 73 and in the housing 76.

The lever 71 is moved when the switching system passes from the first to the second configuration.

Although the holding member 72 of Figures 5 to 7 is associated with the flaps 16 and 18 of Figures 3 and 4, that is to say the flaps 16, 18 having a first portion 21, 31 and a second portion 22 , 32 connected by a pivot axis 33, 40, it can be adaptable to the flap 17 of Figures 1 and 2, that is to say to a flap 17 extending, when observed in a plane perpendicular to its axis pivoting 41 only on one side of this axis 41. The holding member 72 exerts a holding torque on the flap 18. This holding torque is constituted by the force exerted by the spring 70 and the lever arm. When the switching system 10 passes from the first to the second configuration, the force exerted by the spring 70 increases because the spring is compressed. In addition, the cam path 73 is configured so that the successive positions of the movable pin 75 act on the lever arm. Thus, the lever arm decreases with the passage of the switching system 10 of the first in the second configuration. The holding member 72 is thus configured so that the holding torque decreases when the switching system 10 passes from the first to the second configuration.

When the switching system passes from the first configuration to the second configuration, the first portion 31 of the flap 18 progressively opens the outlet 14 of the second duct 12 and the second portion 32 of the flap 18 progressively opens the inlet 13 of the second As a result, the torque exerted on each portion 31, 32 of the flap 18 by the electric supercharger 15 decreases as the switching system passes from the first configuration into the second configuration.

This decrease takes place even if the compressor 15 is in a constant operating regime when the switching system passes from the first configuration to the second configuration.

Thus, the total torque exerted on the flap 18, consisting of the torque generated by the compressor 15 to which is added the torque generated by the holding member 72, remains strictly positive when the switching system passes from the first configuration into the second configuration.

The phrase "including one" should be understood as synonymous with the expression

'Including at least one', except where the opposite is specified.

Claims

claims

An assembly (1) for a thermal engine air circuit, comprising:

a first pipe (11) capable of conveying fluid,

a second conduit (12) extending between an inlet (13) in the first conduit (11) and an outlet (14) in the first conduit (11), so as to form a bypass of a portion of the first pipe (11), the second pipe (12) comprising a pressure variation source (15), and

a fluid referral system (10) in one of the second conduit (12) and in said portion of the first conduit (11), the referral system (10) having a first configuration allowing the fluid to circulating predominantly in said portion of the first conduit (11), the switching system (10) comprising:

a holding member (72) exerting a torque configured to bring or maintain said switching system (10) in the first configuration, and

at least one zone (2, 3) closing in this first configuration all or part of the entry of the second conduit (12) and a zone (2, 3) closing in this first configuration all or part of the outlet of the second pipe (12),

the switching system (10) being arranged to pass into a second configuration allowing the fluid to flow mainly in the second pipe (12) when the pressure variation generated in the second pipe (12) by the source (15) exceeds a predefined value, this pressure variation then exerting on the said zone or zones (2, 3) of the referral system (10) a torque allowing this passage in the second configuration, despite the torque exerted by the holding member (72). )

the holding member (72) being such that the torque exerted on the switching system (10) decreases when the switching system (10) passes from the first to the second configuration.

2. Assembly (1) according to claim 1, being devoid of actuator dedicated to the passage of the switching system (10) of the first in the second configuration.

3. Assembly (1) according to one of the preceding claims, the pressure variation source being an electric supercharger (15) disposed in the second pipe (12).

4. Assembly (1) according to any one of the preceding claims, the switching system (10) comprising at least one pivoting flap (16, 17) and the holding member (72) comprising a spring (70) and a lever (71) rigidly coupled to the flap (16, 17), lever (71) via which the holding torque is exerted on the flap (16, 17), the spring (70) comprising a fixed end (77) and a movable end (78) moving, in particular in translation relative to the lever, when the system The switch (10) moves from the first to the second configuration, the movement being used to vary the lever arm.

5. Assembly (1) according to claim 4, the lever (71) comprising a housing (76) in which can move a movable pin (75) integral with the movable end (78) of the spring to vary the arm of the sink.

6. Assembly (1) according to claim 5, the holding member (72) defining a path (73) guiding the displacement of the movable pin (75) in the housing (76) so that the lever arm takes a succession of predefined values when the switching system (10) passes from the first to the second configuration.