FR3058185A1 - AIR INTAKE CIRCUIT OF A SUPERCHARGED ENGINE - Google Patents

Abstract

The invention relates to an air intake circuit of a supercharged engine engine comprising a compressor (5) placed in said circuit and a bypass circuit (18) comprising a discharge valve (19) and allowing conveying compressed gases downstream of the compressor (5) to an area (26) of the intake line upstream of said compressor (5). The main characteristic of an intake circuit according to the invention is that the section (25) of the bypass circuit (18) between the discharge valve (19) and said zone (26) comprises at least two branches (27). , 28) adapted to convey the gases to the zone (26), said branches (27, 28) being implanted in a conduit (26) delimiting said zone.

Description

® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY © Publication number:

(to be used only for reproduction orders)

©) National registration number

058 185

60498

COURBEVOIE © Int Cl ⁸ : F02 D 23/00 (2017.01)

PATENT INVENTION APPLICATION

A1

©) Date of filing: 28.10.16. (© Priority: © Applicant (s): RENAULT S.A.S. - FR. @ Inventor (s): LHERAUD NICOLAS. ©) Date of availability of the request: 04.05.18 Bulletin 18/18. ©) List of documents cited in the preliminary search report: See the end of this booklet (© References to other related national documents: ® Holder (s): RENAULT S.A.S .. ©) Extension request (s): (© Agent (s): IPSILON Simplified joint-stock company.

The air intake circuit of a supercharged engine.

FR 3 058 185 - A1

The invention relates to an air intake circuit of a supercharged vehicle engine comprising a compressor (5) placed in said circuit and a bypass circuit (18) comprising a discharge valve (19) and allowing '' conveying compressed gases downstream of the compressor (5) to a zone (26) of the intake line located upstream of said compressor (5).

The main characteristic of an intake circuit according to the invention is that the section (25) of the bypass circuit (18) comprised between the discharge valve (19) and said zone (26) comprises at least two branches (27 , 28) capable of conveying the gases towards the zone (26), said branches (27, 28) being located in a conduit (26) delimiting said zone.

AIR INTAKE CIRCUIT OF A SUPERCHARGED ENGINE

The invention relates to an air intake circuit of a supercharged engine.

On a supercharged spark ignition engine, it is necessary to quickly drop the excess pressure downstream of a supercharging compressor each time the throttle valve is closed. The pressure is dropped to improve the reliability of the compressor wheel. For this, some engines can use a relief valve located downstream of the compressor, which returns air to the compressor inlet.

For example, application FR2986274 describes a method of controlling a supercharging carried out by means of an engine architecture comprising a compressor coupled to a turbine, an intake manifold and a bypass circuit of said compressor controlled by a valve. discharge, said circuit for deflecting part of the supercharged gases downstream of the compressor to an area located upstream of said compressor. Such a method makes it possible to determine the conditions for opening the relief valve.

However, in general, when it decides to open the discharge valve, an unacceptable noise is produced at the opening thereof, by recirculation of the compressed air in the low pressure section of the intake circuit of air. This noise then goes up the entire low pressure intake circuit, before being radiated by the intake port, then transmitted to the passenger compartment.

To solve this noise problem, current or previous applications use traditional acoustic devices between the source and the air intake mouth, such as Helmholtz resonators, quarter waves, foams, or ducts porous. But all these devices just attenuate the noise without preventing it from occurring, and moreover require a rigorous and precise installation to be really effective. These devices are expensive and cumbersome solutions in the engine compartment of motor vehicles.

An air intake circuit of a supercharged engine according to the invention makes it possible to attenuate, or even cancel, at its source the noise emitted by the discharge valve, by overcoming in particular the drawbacks noted in the 'state of the art.

For a good understanding of the invention, the concepts of "bypass" and "bypass circuit" are equivalent.

The invention relates to an air intake circuit of a supercharged vehicle engine comprising a compressor placed in said circuit and a bypass circuit comprising a discharge valve and making it possible to convey compressed gases downstream of the compressor to an area of the intake line located upstream of said compressor.

The main characteristic of an air intake according to the invention is that a section of the bypass circuit between the relief valve and said zone comprises at least two branches capable of conveying the gases to the zone, said branches being located in a conduit delimiting said zone. In this way, the gas flows coming from the different branches which are in communication with the duct delimiting the zone, penetrate both into said duct and into the other branches, significantly limiting the quantity of gas brought up into said duct. In this way, the noise produced in said conduit and caused by the opening of the valve is greatly reduced. Indeed, part of this noise is evacuated at the level of these branches, greatly attenuating the noise going up in the admission circuit to the admission entrance. The conduit can for example be constituted by a cylindrical tube and the branches can for example be constituted by cylindrical tubes. The vehicle engine is a heat engine which may for example be petrol or diesel. The bypass circuit is a circuit mounted in parallel on the main air intake circuit. It is assumed, for example, that the compressor is coupled to a turbine placed on an exhaust line, to form a turbocharger. Alternatively, the compressor can also be an electric compressor.

Advantageously, the section of the branch circuit comprises an even number of branches, the branches being located in the conduit so as to constitute pairs of branches facing each other around said conduit. Indeed, so that noise attenuation is optimized, each branch is located in the conduit so as to find itself opposite another branch. In this way, a larger fraction of gas from a branch will enter the branch opposite. Two branches are assumed to be located opposite one another if their longitudinal axes, or neutral fibers, are aligned and overlapping.

Preferably, the cross section of the gases in each of the branches is less than the cross section of the gases in the duct.

Preferably, the gas passage sections in the branches are identical.

Advantageously, the conduit is cylindrical, the section of the branch circuit comprising two branches implanted in said conduit in diametrically opposite manner. This is a simple configuration limiting the number of branches installed in the conduit, and making it possible to greatly reduce the noise produced by the opening of the relief valve.

Advantageously, the gas passage section in each of the branches is substantially equal to half of the section passage section if it consisted of a single branch.

Preferably, each branch ends in a rectilinear segment implanted in the conduit. In this way, the gases will tend to penetrate the duct without being disturbed by swirling movements, facilitating the penetration of the gases into the branch located opposite.

Preferably, the length of the rectilinear segment is between 2 times and 5 times its internal diameter. This ratio makes it possible to obtain an optimized length of each branch as a function of its internal diameter in order to obtain a straight and undisturbed gas outlet in the conduit.

According to a first preferred embodiment of an intake circuit according to the invention, the relief valve is offset, the bypass circuit being separate from the compressor. In this way, the bypass circuit comprising the discharge valve is independent of the compressor and can therefore be mounted separately from it.

According to another preferred embodiment of an intake circuit according to the invention, the relief valve is integrated in a casing of the compressor. For this configuration, the position of the relief valve is fixed relative to that of the compressor, allowing good reproducibility of mounting an intake line according to the invention.

An intake circuit according to the invention has the advantage of being particularly effective, by attenuating the noise produced by the opening of the discharge valve from its source, by means of an original geometry of the bypass circuit comprising said . A consequence of this advantage is that such an intake circuit is simple and space-saving in design, in particular avoiding the use of bulky means and requiring good mounting precision, to counteract the noise once it this was created.

A detailed description is given below of a preferred embodiment of an intake circuit according to the invention, with reference to the following figures,

FIG. 1 is a schematic view of the architecture of an internal combustion engine of the state of the art, comprising a turbocharger as well as a bypass circuit comprising a relief valve,

FIG. 2A is a side view of a compressor and of a branch circuit of an intake circuit according to the invention,

FIG. 2B is a view from another angle of the compressor and of the branch circuit of FIG. 2A,

FIG. 3 is an enlarged schematic view of the connection zone between a branch circuit and an intake duct of an intake circuit according to the invention,

FIG. 4A is a schematic and partial view of a first embodiment of an intake circuit according to the invention,

FIG. 4B is a schematic and partial view of a second embodiment of an intake circuit according to the invention.

Referring to FIG. 1, an example of an internal combustion engine structure 1 involving a turbocharger 2, comprises an air inlet 3, an air filter 4, a duct 30 for conveying air to the compressor 5, then a pipe 6 connecting said compressor 5 to an intake manifold 7 placed upstream of the engine 8, for conveying supercharged air to said engine 8, passing through a supercharged air cooler 9 (RAS). The exhaust gases exit from the engine 8 via an exhaust manifold 10, which convey said burnt gases to the turbine 11 by means of a connecting pipe 1 2, the air leaving the turbine 11 being oriented towards a catalyst 13 before being evacuated to the outside of the vehicle. The flow of supercharged air is regulated in the pipe 6 by means of a valve, which can advantageously be constituted by a throttle housing 14 placed between the cooler 9 and the intake manifold 7. The throttle housing 14 comprises a valve 17 of pivoting regulation, being able to open or close according to the phases of use of the engine. The exhaust gases can be sent directly to the catalyst 13, without passing through the turbine 11, by means of a bypass 15 equipped with a relief valve type valve 16, said valve 16 being urged to regulate the flow of gas passing through the bypass 15, and therefore, consequently, the gas flow passing through the turbine 11.

This engine structure 1 also comprises a bypass 18 at the compressor 5, for conveying supercharged air from a downstream area of said compressor 5 located upstream of the throttle body 14, to an upstream area of the compressor 5 located downstream of the filter air 4. The air flow passing through this bypass 18 is controlled by means of a discharge valve 19, for example a pneumatic or electric valve, placed in said bypass 18. This bypass 18 at the compressor 5, when 'it is open, makes it possible to lower the pressure of the supercharged gases produced in the line 6 by the compressor 5, by evacuating a part of these gases. This engine structure 1 has here a first pressure sensor 20 of supercharged air located between the RAS 9 and the throttle body 14, and a second sensor 21 placed in the intake manifold 7, the pressure measurements acquired by these two sensors 20, 21 dictating the configuration of the butterfly housing 14 as well as that of the relief valve 19.

The intake circuit includes all the elements between the air inlet 3 and the intake manifold 7, itself being assumed to be included in said circuit.

Referring to FIGS. 2A and 2B, the branch 18 comprising the discharge valve 19 has an upstream section 22 connecting a conduit 23 of the intake circuit located downstream of the compressor 5 to a cavity 24 enclosing the discharge valve 19, and a downstream section 25 connecting said cavity 24 to a duct 26 of the intake circuit located upstream of said compressor 5. This downstream section 24 is here divided into two branches 27, 28 each connecting the cavity 24 to said upstream duct 26. The cavity 24 containing the discharge valve 19 and the upstream conduit 26 are cylindrical, and the two branches 27, 28 are implanted in said cavity 24 in diametrically opposite directions and are implanted in said upstream conduit 26 in diametrically opposite directions. Each branch 27, 28 thus comprises a first rectilinear segment 29 implanted in the cavity 24, extended by a second curved segment 30 itself extended by a third rectilinear segment 31 opening into the upstream conduit 26, said first segment 29 and said third segment 31 being here parallels. In this way, each branch can have a C-shaped or U-shaped profile. Each of the two branches 27, 28 is composed of a cylindrical tube connecting the cavity 24 to the upstream conduit 26, the two branches 27, 28 having the same diameter. Preferably, the length of the third segment 31 is greater than or equal to three times its diameter to allow the gas flowing in the branch 27, 28 to open into the upstream conduit 26 without being disturbed.

The gases compressed in the conduit 23 located downstream of the compressor 5, can be evacuated towards the upstream conduit 26, via the bypass 18 by means of an opening of the discharge valve 19. The gases thus first pass through the section upstream 22 of the bypass 18, then through the cavity 24 housing the discharge valve 19.

Referring to Figure 3, said gases then progress in the two branches 27, 28 to open into the upstream conduit 26 of the intake circuit. Due to the particular arrangement of the arrival of these two branches 27, 28 in the upstream channel 26, namely by being diametrically opposite, a fraction of the gases coming from one of the two branches 27, 28 and emerging in the channel upstream 26, will rush into branch 27, 28 located opposite, thereby reducing the fraction of gases brought up in said upstream channel 26 towards the air inlet 3. This phenomenon is reciprocal with the other branch 27 , 28 and therefore benefits the two branches 27, 28. Consequently, the quantity of gases coming from the branches 27, 28 of the bypass 18 and intended to go up in the intake circuit up to the intake inlet 3 , is greatly reduced, thus greatly attenuating or even canceling out the noise associated with the rise of gases in said circuit.

Referring to FIG. 4A, according to a first preferred embodiment of an air intake circuit according to the invention, the discharge valve 19 is offset so that the bypass 18 is external to the compressor 5. For this configuration the compressor 5 and the bypass 18 are two independent elements which must be mounted separately, while respecting a certain rigor and a certain precision.

Referring to FIG. 4B, according to a second preferred embodiment of an air intake circuit according to the invention, the discharge valve 19 is integrated into a casing 32 of the compressor 5. For this configuration, the compressor 5 and the discharge valve 19 are combined to form a compact assembly that is easy to assemble.

Claims (10)

REVENDI CATI ONS 1. Air intake circuit of a supercharged vehicle engine comprising a compressor (5) placed in said circuit and a bypass circuit (18) comprising a discharge valve (19) and making it possible to convey compressed gases downstream of the compressor (5) to a zone (26) of the intake circuit located upstream of said compressor (5), characterized in that a section (25) of the bypass circuit (18) included between the valve (19 ) of discharge and said zone (26) comprises at least two branches (27, 28) capable of conveying the gases towards the zone (26), and in that said branches (27, 28) are implanted in a conduit (26) delimiting the said zone. 2. Intake circuit according to claim 1, characterized in that the section (25) of the branch circuit (18) comprises an even number of branches (27, 28), and in that the branches (27, 28) are implanted in the conduit (26) so as to constitute pairs of branches (27, 28) facing each other around said conduit (26). 3. Intake circuit according to any one of claims 1 or 2, characterized in that the cross section of the gases in each of the branches (27, 28) is less than the cross section of the gases in the duct (26 ). 4. Intake circuit according to any one of claims 1 to 3, characterized in that the gas passage sections in the branches (27, 28) are identical. 5. Intake circuit according to any one of claims 1 to 4, characterized in that the duct (26) is cylindrical, and in that the section (25) of the branch circuit (18) comprises two branches (27 , 28) located in said conduit (26) in diametrically opposite manner. 6. Intake circuit according to claim 5, characterized in that the gas passage section in each of the branches (27, 28) is substantially equal to half of the gas passage section in the section (25) if it consisted of a single branch. 5 7. Intake circuit according to any one of claims 5 or 6, characterized in that each branch (27, 28) ends in a segment (31) rectilinear implanted in the conduit (26). 8. Intake circuit according to claim 7, characterized in that the length of the rectilinear segment (31) is between 2 times and 5 times 10 its internal diameter. 9. Intake circuit according to any one of claims 1 to 8, characterized in that the relief valve (19) is offset and in that the bypass circuit (18) is separate from the compressor (5). 10. Intake circuit according to any one of claims 1 to 8, characterized in that the relief valve (19) is integrated in a housing (32) of the compressor (5). 1/2