Intake manifold for a heat engine having an optimized recirculation gas mixer - Patents.com

Abstract

An intake circuit (10) for a heat engine, comprising a burnt gas recirculation system (30) intended to be positioned between an air compression element and an upper portion of a combustion chamber (11) hollowed out of a cylinder head (20) of the engine, the intake circuit comprising the cylinder head, an intake manifold (12) with a plenum (16), and an intake duct (21), characterized in that the recirculation system (30) comprises a burnt gas injection duct (17) leading to the plenum (16), said duct (17) being capable of transporting burnt gases against the flow of intake air (32). [Selected figure] Figure 2

Description

[Technical field]

[0001] The present invention relates to motor vehicle internal combustion or heat engines.

[0002] The invention relates more particularly to an intake manifold of a heat engine, comprising a device for mixing burnt gases.

[0003] The invention also relates to a recirculation system for the burnt gases of a heat engine. [Background technology]

[0004] prior art The present invention relates to an internal combustion engine, in particular intended to be equipped in a motor vehicle, employing means for recirculating burnt gases.

[0005] The invention more particularly relates to a means for recirculating the burnt gases of an internal combustion engine, either output by the exhaust circuit of the engine, either directly as close as possible to the exhaust manifold, in which case the burnt gases are considered to be at high pressure, or in a pollution abatement system downstream of the exhaust manifold, in which case the burnt gases are considered to be at low pressure, or output from an oil separation step passing through an oil separator, in which case the burnt gases are known as blow-by gases.

[0006] The standards with regard to pollution and consumption, especially of internal combustion engines fitted in motor vehicles, are becoming increasingly stringent in industrialized countries. The automotive industry is therefore currently seeking technical solutions to meet these obligations without excessively sacrificing the performance of the heat engine or its cost. A known technique for reducing pollution of such internal combustion engines is to recirculate the burnt gases, i.e. to return a portion of the burnt gases to the intake air and mix it with the fresh air drawn in, in order to reduce the nitrogen oxides. This technique consists in reinjecting a portion of the exhaust gases into the combustion chamber of the engine, depending on the operating conditions of the engine, which has the effect of proportionally reducing the amount of oxidant gases, thus lowering the combustion temperature and, as a result, reducing the production of NOx, i.e. nitrogen oxides.

[0007] For example, a commonly employed process involving low pressure burnt gases is the "external recirculation" of exhaust gases using an EGR (exhaust gas recirculation) valve to recirculate the exhaust gases, opening and closing the line connecting the exhaust manifold to the intake manifold of the engine. The EGR valve allows a predetermined amount of gases taken from the exhaust to be injected at the intake, depending on the operating conditions of the engine.

[0008] Burnt gases are typically injected into the engine intake manifold or directly into the engine intake duct between the engine intake manifold and the combustion chamber during engine intake.

[0009] Thus, the publication EP 1 447 533-A1 proposes a direct injection of the blow-by gases into an intake duct leading to the combustion chamber of the engine: the gases pass through a channel which leads into the intake duct.

[0010] A drawback of this type of injection is that the mixture formed by the blow-by gases and air is not optimal, which can limit the performance of the engine.

[0011] As is known, the burnt gases can be collected in a recirculation ramp extending approximately parallel to the longitudinal axis X of the engine. An intake channel leads to the ramp, which connects the ramp to one of the intake ducts of the engine.

[0012] Thus, US Patent Application Publication No. 20090301448(A1) proposes a lamp for collecting blow-by gases injected into the intake duct of an engine.

[0013] In the same way as the previous type of injection, the intake channel for the burnt gases leads directly to the intake duct leading to the combustion chamber, which does not allow optimal mixing of the burnt gases and air before entering the combustion chamber, which can reduce the performance of the engine.

[0014] Publication FR2946699-A1 discloses a lamp for collecting burnt gases, which runs parallel to the axis of the engine and is connected to an intake manifold plenum arranged downstream of an air / water heat exchanger in the direction of air flow, the connection being made by a channel leading to the plenum.

[0015] A drawback of this type of burnt gas injection is also the mixing of the burnt gas and air which is not optimal and tends to reduce engine performance.

[0016] US Patent Application Publication No. 2015002078(A1) proposes the injection of burnt gases into the plenum of a heat engine intake manifold by a duct penetrating upstream into the plenum of the intake manifold, the duct having gas injection orifices facing the combustion chamber.

[0017] A disadvantage of this type of injection is that not only does the penetrating duct cause a pressure drop in the air flow to the combustion chamber, but it also tends to produce a less than optimal mixture, reducing engine performance. Summary of the Invention

[0018] The object of the present invention is to propose an intake circuit with recirculation of burnt gases for a gasoline or diesel heat engine, remedying the above-mentioned drawbacks and improving the intake circuits with mixing of burnt gases for heat engines known in the prior art, in order to provide an optimal mixing of the recirculated burnt gases with air before entering the combustion chamber, while causing little, if any, pressure drop in the gas flow.

[0019] The internal combustion engine according to the invention has a gas recirculation system, which includes the withdrawal of burnt gases, which may be high pressure burnt gases from the exhaust circuit of the engine upstream of the pollution abatement system, for example from the exhaust manifold of the engine, or from the pollution abatement system or downstream of the system, or from oil vapors, which may be withdrawn downstream of the oil separator. The recirculation system allows the burnt gases to be drawn into the intake of the engine by injection of the gases into the intake manifold plenum, minimizing the pressure drop and optimizing the mixing of the gases with the fresh intake air.

[0020] The invention relates to an intake circuit for a heat engine, comprising a recirculation system for burnt gases or blow-by gases, positioned between an air compression element and at least one upper part of a combustion chamber which is part of the cylinder head of the engine, the intake circuit comprising a cylinder head, an intake manifold and at least one intake duct, the recirculation system comprising at least one burnt gas injection duct bounded by a side wall, an upper wall and a lower wall in the direction of air flow, leading to a plenum of the manifold, the duct being capable of transporting the gases in countercurrent to the intake air flow.

[0021] Advantageously, the system comprises at least one burnt gas injection duct, which leads to the plenum of the manifold and is capable of conveying gases countercurrent to the airflow so as to improve the mixing of the gases with the air before entering the combustion chamber of the engine. The gases are first directed countercurrent to the intake airflow and then directed back towards the intake duct, thereby improving the mixing of the gases with the intake air. The arrangement of the injection duct in the plenum is provided so as to cause little pressure drop in the airflow.

[0022] According to a further feature of the invention, - at least one ejection duct leads into the plenum coincident with the axis of at least one associated intake duct;

[0023] Advantageously, the injection duct extends substantially coincident with the axis of the at least one intake duct so as to convey the burnt gases which are mixed and led to the intake duct. - an outlet of at least one injection duct into the plenum is spaced apart from an outlet of at least one associated intake duct into the plenum;

[0024] Advantageously, the outlet of the at least one injection duct into the plenum is remote from the outlet of the at least one associated intake duct into the plenum so that the burnt gases and the intake air are better mixed before entering the at least one associated intake duct. At least one injection duct has a tubular channel penetrating into the plenum of the manifold.

[0025] Advantageously, the injection ducts are cylindrical and straight to minimize pressure drop of the burnt gas flow, especially during injection into the plenum of the manifold.

[0026] Advantageously, the injection duct has a tubular channel penetrating into the plenum of the manifold, in order to obtain an optimal position for the injection of the burnt gases into the plenum, midway through the intake flow, improving mixing. The tubular channel has an opening facing upstream in the air flow direction.

[0027] Advantageously, the tubular channels have openings facing upstream in the airflow, allowing better injection of the burnt gases and better diffusion and mixing of the burnt gases within the airflow. The tubular channel is provided with an oblique opening facing in the upstream direction of the intake air flow.

[0028] Advantageously, the tubular channels have bevelled openings, the openings facing in the upstream direction of the airflow to allow optimal mixing of the burnt gases with the intake air. The tubular channel extends in the upstream direction of the air flow from a deflection wall which can direct the air flow towards an opening connected to an intake duct.

[0029] Advantageously, in order to reduce the pressure drop when the mixture of air and burnt gases is taken into the intake duct, the plenum is bounded by side walls, an upper wall, a lower wall and a downstream airflow deflection wall capable of directing the airflow towards an opening connected to the intake duct.

[0030] The tubular channel extends from the deflecting wall in the upstream direction of the gas flow to direct the gas in the upstream direction of the intake air flow and thus as a counterflow to the intake air flow. - The deflection wall and the tubular channel are made in one piece.

[0031] Advantageously, the deflection wall and the tubular channel are made in one piece, for easier manufacture as well as easier attachment to the cylinder head and formation of the plenum. The recirculation system comprises a supply rail extending transversely to the air flow axis, the rail being connected to at least one gas injection duct.

[0032] Advantageously, the recirculation system comprises a supply rail connected to the burnt gas circuit, the rail extending transversely to the direction of air flow and parallel to the axis of the engine so as to be able to blow into all of the intake ducts of the engine. The supply rail is either hollowed out in the cylinder head or is fixed to the lower wall of the plenum or is fixed to the upper wall of the plenum.

[0033] Advantageously, the supply rail, which extends transversely to the intake air flow, is hollowed out of the cylinder head or is fixed to the bottom wall or to one of the bottom or top walls of the plenum, which allows both simple circuitry and easy implementation. - The supply rail is connected to the outlet of the blow-by gas separator.

[0034] Preferably, the supply rail is connected to an outlet of the blow-by gas separator to return the blow-by gas to the intake. - The supply rail is connected to the exhaust gas circuit.

[0035] Preferably, the supply rail is connected to a circuit for burnt gases from the exhaust of the engine, the gases being capable of being high pressure burnt gases or low pressure burnt gases.

[0036] Further features and advantages of the invention will become apparent from reading the following description of particular embodiments of the invention, given as non-limiting examples and illustrated in the accompanying drawings, in which: [Brief description of the drawings]

[0037] [Figure 1] FIG. 1 is a schematic cross-sectional view of an intake circuit of a heat engine. [Diagram 2] 1 is a schematic cross-sectional view of a cylinder head and an intake manifold according to a first embodiment of the present invention. [Diagram 3] 1 is a schematic top view of a cylinder head having an intake circuit according to the present invention; [Figure 4] 4 is a schematic cross-sectional view of a cylinder head and intake manifold according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Detailed explanation of the figure In the following description, the same reference numerals denote the same parts or parts having similar functions.

[0039] In this specification, the expression "opening" is understood to mean the surface of the duct for the passing gas, this part being, as the case may be, transverse to the axis of the duct or at an angle to the axis of the duct.

[0040] The terms "upstream / downstream" refer to the direction of air flow in the intake circuit.

[0041] The terms "upper / lower" refer to a longitudinal axis perpendicular to a horizontal plane parallel to the mating surfaces of the crankcase and cylinder head of the described engine.

[0042] Thermal or internal combustion engines of motor vehicles have both systems for reducing the pollution caused by burnt gases from the combustion chambers of the engine, and supercharging systems for improving the efficiency of the engine.

[0043] To reduce pollution, it is known to return at least a portion of the burnt gases to the intake air of the engine, which is then mixed with the fresh air before it enters the cylinders of the engine. A distinction is made between several types of recirculation of the burnt gases: low pressure recirculation, which involves taking off the burnt gases downstream of a pollution abatement device, such as a catalytic converter, in the direction of the exhaust gas flow, or high pressure recirculation, in which the burnt gases are drawn off upstream of the pollution abatement device, preferably at the outlet of the cylinder head of the engine. The burnt gases, called high pressure burnt gases, are thus taken off in an exhaust manifold fixed to the exhaust face of the cylinder head of the engine.

[0044] The burnt gases can therefore come from an oil vapour separator and are called blow-by gases. The separator is generally placed at the top of the engine. It allows the separation of the oil contained in the vapours from the gases. The oil is then returned by an oil return circuit to an oil sump, preferably arranged at the bottom of the engine, and the gases can be returned towards the intake of the engine.

[0045] Generally, according to FIG. 1, the heat engine 100 has a crankcase 101 with at least one cylinder 102 in which a piston can slide along the axis of at least one cylinder, and a cylinder head 20 covering the upper part of the crankcase and thus sealing at least one combustion chamber 11. The combustion chamber is delimited by the respective walls of the cylinder, the piston and the cylinder head 20. The intake ducts 21 and the exhaust lines connecting the combustion chamber 11 of each cylinder to the intake circuit 10 and the exhaust circuit, respectively, are hollowed out of the cylinder head. The intake circuit 10 is fixed to the cylinder head 20 by an intake face 23. The exhaust circuit is fixed to the cylinder head by an exhaust face (not shown) symmetrically facing the intake face with respect to a vertical median plane passing through the longitudinal axis X of the engine.

[0046] The longitudinal axis X of the engine is generally parallel to the axis of the crankshaft contained in the engine.

[0047] Fresh air 40 is drawn in from outside the vehicle and then mixed with the burnt gases 41 in an intake manifold 12 fixed to the intake wall 22 on the side of the intake face 23 of the cylinder head 20 of the engine. The mixture is then conveyed to the combustion chamber 11 of the engine via an intake duct 21. At the top of each cylinder of the crankcase 101, the mixture of air and burnt gases is injected into the combustion chamber where it is mixed with fuel to cause an explosion, thereby producing the burnt gases. The burnt gases are then pushed out of the combustion chamber via an exhaust line towards an exhaust circuit fixed to the cylinder head on the side of the exhaust face of the engine.

[0048] The present invention relates to an intake circuit 10 for a heat engine, comprising a recirculation system 30 for returning burnt gases to the intake of the engine.

[0049] Burnt gases are understood to be gases from the exhaust circuit or blow-by gases.

[0050] In the remaining description, the return of blow-by gases to the intake will be described to make the invention easier to understand, however, the burnt gases may be high pressure or low pressure burnt gases or a mixture of burnt gases.

[0051] As is known, fresh intake air 40 is drawn in from the front of the vehicle and passes through an intake circuit in order to be injected into the respective combustion chambers 11 of the cylinders. The intake air is first filtered by an air filter to remove impurities and dust carried by the intake air. It is also known that the pressure of the drawn in gases can then be increased to better fill at least one cylinder of the engine with a fuel / air mixture in order to improve the performance of the engine. Thus, the power density of the engine, together with its power, is increased and the engine consumption is reduced. An intake compression stage is therefore arranged between the air filter and the engine. This compression stage (not shown) can be formed by a compression stage of a turbocharger or by an electric compressor.

[0052] Downstream of the compression stage, the compressed air is hot and its density is reduced, which is detrimental to the engine's performance. It is therefore useful to have an intake air cooling stage adjacent to the compressor (not shown), downstream of it in the direction of air circulation from the compressor. This cooling stage can consist of a cooler 14, more specifically an air / water heat exchanger. Water at a suitable temperature passes through the heat exchanger 14 to remove some of the heat from the compressed air.

[0053] The compressed and cooled air 40 is then conducted to an intake manifold 12 for controlling the flow of air admitted to the combustion chambers. The manifold is fixed by a flange 13 to a fixed wall 22 on the intake face 23 of the engine's cylinder head 20, and conducts the compressed and cooled air to an intake duct 21 hollowed out in the cylinder head. The cylinder head intake duct 21 has a particular shape and profile depending on the type of engine, e.g. diesel or spark ignition.

[0054] The cooler 14 is also known as WCAC, which stands for water charge air cooler. The manifold 12 is substantially characterized by a plenum 16 or charge chamber before entering the intake duct 21 of the cylinder head. The manifold 12 is downstream of the WCAC heat exchanger 14, and in our embodiment the manifold 12 and the WCAC heat exchanger 14 share the same casing. The casing is fixed to a fixed wall 22 of the cylinder head. The fixed wall 22 extends in a plane, for example inclined with respect to a horizontal plane that is parallel to the mating surface 25 between the cylinder head and the crankcase. This inclination allows easier installation of the cooler and more reliable retention.

[0055] The plenum 16 is bounded in the direction of air flow by side walls, an upper wall 36 and a lower wall 35 .

[0056] 1 to 4, the cooler 14 and the intake manifold 12 are integrally formed 15 .

[0057] The following description is given for one cylinder for ease of understanding, however, the engine according to the invention has at least one cylinder and the invention proposes an injection duct for each cylinder.

[0058] According to Figures 1 to 4, the recirculation system 30 comprises a supply rail 31 for burnt gases, which is connected to the exhaust circuit or to the gas outlet from an oil vapour separator (not shown).

[0059] Preferably, the intake rail 31 extends parallel to the longitudinal axis X of the engine. The rail can be obtained by drilling a hole in the cylinder head, which means that it is arranged inside the cylinder head, as shown in Figures 1 and 2, or it can be fixed to an element of the intake circuit 10 of the engine, which means that it is arranged outside the engine, as shown in Figure 4. The intake rail makes it possible to transport the burnt gases to the intake of the engine.

[0060] The injection duct 17 is fluidly connected to the intake rail 31 and the plenum 16. The duct is generally cylindrical and straight so as to minimize the pressure drop of the burnt gas flow. Preferably, the injection duct 17 is arranged to lead to the plenum 16 of the manifold upstream of the intake duct connected to the associated cylinder. The injection duct allows an injection of the burnt gas 41 to mix with the intake air, which is then led to the associated intake duct leading to the cylinder. In this description, there is one intake duct 21 for each cylinder of the engine. Typically, the intake duct 21 leads to two secondary intake branches (not shown) that lead to the combustion chamber of the cylinder.

[0061] According to FIG. 3, the intake circuit comprises an intake rail 31, which extends parallel to the longitudinal axis X of the engine and transversely to the direction E of the flow of intake air in the plenum 16 of the intake manifold. An injection duct 17, whose axis is substantially perpendicular to the axis of the intake rail 31, opens at a first end into the intake rail 31 and at a second, opposite end into the plenum 16. The number of injection ducts 17 is preferably equal to the number of cylinders of the engine. Thus, the injection ducts 17 extend perpendicularly to the axis X of the engine from the injection rail 31 in the associated cylinder along the axis X of the engine. Each injection duct opens into the plenum 16 in line with the axis of the intake duct 21. More precisely, the projection of the outlet of the injection duct 17 into the plenum 16 in the horizontal plane is arranged within the projection of the axis of the associated intake duct in the same horizontal plane, as shown in FIG. 3. The outlet of the intake duct into the plenum is disposed generally forward of the inlet of the associated intake duct 21. Each of the injection ducts 17 extends linearly and is directed from the wall of the plenum 16 in the upstream direction A of the intake air flow for conveying the burnt gases in a counterflow to the intake air flow direction. m This has led to the following.

[0062] 2-4, the airflow is represented by arrows 32 and the injection of burnt gases into the plenum is represented by arrows 33.

[0063] The injection duct 17 preferably comprises a tubular channel 18 penetrating the plenum along the intake duct 21, preferably away from the outlet of the intake duct 21 into the plenum 16, so as to optimally position the injection point of the burnt gases 41 in the flow of intake air 40. The tubular channel extends from the wall of the plenum in the upstream direction A of the flow of intake air. m The distance may for example be greater than 20 mm so as to allow optimal mixing of the burnt gases with the intake air before entering the intake duct 21 leading to the cylinder.

[0064] Preferably, the tubular channel 18 is substantially inclined along a vertical plane relative to the axis of flow E of the intake air 40, as shown in Figs.

[0065] The tubular channel 18 is arranged at its free end 18' in the upstream direction A of the air flow. m The openings may be cut at an angle, for example, and may be oriented in the upstream direction A of the air flow. m The opening is directed toward the

[0066] Thus, the burnt gases 41 are directed counter-flow to the flow of intake air 40 and then returned in the direction of intake air to the intake duct 21, thereby substantially improving mixing of the burnt gases with the air before they enter the intake duct 21.

[0067] 2, the tubular channel 18 extends from an inclined deflection wall 34 that downstream bounds the plenum 16. According to a preferred embodiment, the plenum 16 comprises a portion hollowed out from the cylinder head 20.

[0068] 1-4, the deflection wall 34 is inclined with respect to the axis of the flow of air E. More precisely, the axis perpendicular to the deflection wall intersects, in a vertical plane, with the axis of the flow of air E. The tubular channel 18 can present an inclination with respect to an axis perpendicular to the surface of the deflection wall 34, or can be substantially parallel to the axis, so as to present an inclination with respect to the axis of the flow of gas E.

[0069] Preferably, the tubular channel 18 and the deflection wall 34 are made as one piece, for example obtained by molding. As the tubular channel 18 and the deflection wall 34 are not exposed to high temperatures, they can be made from a plastic material.

[0070] 4, the supply rail 31 is fixed below a lower wall 35 that defines the boundary of the plenum. The injection ducts 17 run through the lower wall 35 in the upstream direction A of the air flow, at an angle to an axis perpendicular to the inner surface of the wall. m The injection duct 17 passes through the intake air in the upstream direction A. m or into a tubular channel 18 which preferably extends from the lower wall 35 at an angle in a direction directed towards the heat exchanger 12 .

[0071] According to another embodiment, not shown, the injection rail 31 is fixed on the top wall 36 of the plenum. The injection ducts 17 are arranged to face the top wall 36 in the upstream direction A of the air flow at an angle to an axis perpendicular to the inner surface of the wall. m The injection duct 17 passes through the intake air in the upstream direction A. m or into a tubular channel 18 which preferably extends from the upper wall 36 at an angle in a direction directed towards the heat exchanger 12 .

[0072] The tubular channel 18 is preferably arranged at its free end 18' in the upstream direction A of the gas flow. m The opening is directed toward the

[0073] The openings can be formed by an inclined cut on the tubular channel, and the openings are aligned in the upstream direction A of the intake air flow. m or, in this case, facing the heat exchanger 12.

[0074] Preferably, the tubular channel 18 has a smaller cross-sectional area to reduce the pressure drop in the air flow.

[0075] The object is achieved. The burnt gas recirculation system 10 for the intake circuit according to the invention makes it possible to improve the mixing of gas and air without causing an excessive pressure drop in the intake flow.

[0076] Of course, the present invention is not limited solely to the embodiments described above by way of example, but includes all its variants.

[0077] For example, the tubular channels can be replaced by protrusions on the inner surface of the deflecting wall or below the manifold.

[0078] The tubular channel 18 may also extend parallel to an axis perpendicular to the lower wall 36 or the deflection wall 34, and may extend in the upstream direction A of the air flow. mIt may have an opening for injection of burnt gases directed towards the

[0079] Another exemplary embodiment is a tubular channel having a free end 18′ facing the upstream direction A of the air flow. m The nozzle may have a radial opening facing the nozzle.

Claims

1. An intake circuit (10) for a heat engine, comprising: a recirculation system (30) for gases output from said heat engine, adapted to be positioned between an intake compression stage and an upper portion of a combustion chamber (11) hollowed out in a cylinder head (20) of the engine, the intake circuit (10) comprises the cylinder head, an intake manifold (12) with a plenum (16), and at least one intake duct (21); In the intake circuit (10), the recirculation system (30) comprises at least one injection duct (17) leading to the plenum (16); the injection duct (17) is capable of conveying the gas in counterflow to the flow of intake air (32); the at least one injection duct (17) leads to a tubular channel (18) penetrating the plenum (16) of the intake manifold (12); The intake circuit (10), characterized in that the tubular channel (18) extends in an upstream direction of the flow of the intake air (32) from a deflection wall (34) capable of directing the flow of the intake air (32) towards the outlet of the at least one intake duct (21).

2. 2. An intake circuit (10) according to claim 1, characterized in that, in a top view, each of the at least one injection duct (17) is aligned with a central axis of one of the at least one intake ducts (21) in the flow direction of the intake air (32).

3. 3. An intake circuit (10) according to claim 1 or 2, characterized in that the outlet of the at least one injection duct (17) into the plenum is remote from the outlet of the at least one intake duct (21) into the plenum.

4. 4. An intake circuit (10) according to any one of claims 1 to 3, characterized in that the tubular channel (18) has an opening facing in the upstream direction (Am) of the flow of the intake air (32).

5. 5. An intake circuit (10) according to any one of claims 1 to 4, characterized in that the tubular channel (18) has an oblique opening facing in the upstream direction (Am) of the flow of the intake air (32).

6. 6. A suction circuit (10) according to any one of the preceding claims, characterized in that the deflection wall (34) and the tubular channel (18) are made in one piece.

7. 7. The intake circuit (10) according to any one of claims 1 to 6, characterized in that the recirculation system (30) comprises a supply rail (31) extending transversely to the air flow axis (E), said supply rail being connected to said at least one injection duct (17).

8. 8. The intake circuit (10) according to claim 7, characterized in that the supply rail (31) is hollowed out of the cylinder head (20) or is fixed to one of the lower wall (35) or the upper wall (36) of the plenum (16).

9. An intake circuit (10) according to claim 7 or 8, characterised in that the supply rail (31) is connected to the outlet of a blow-by gas separator.

10. 9. An intake circuit (10) according to claim 7 or 8, characterized in that the supply rail (31) is connected to an exhaust gas circuit.

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