AT520737B1 - Air intake system for a combustion engine - Google Patents

Abstract

The invention relates to an air intake system (7) for an internal combustion engine (1) having an intake manifold assembly (8) which has at least one first intake manifold (9) and at least one second intake manifold (10), wherein per cylinder (2) from the first intake manifold (8). 9) at least a first single suction line (17) and per cylinder (2) from the second intake manifold (10) at least a second single intake (18) emanates, and wherein the first (17) and the second intake (18) upstream a transfer opening (22) for connection to a cylinder head (21) to a total intake line (19) unite, in which - at least one exhaust gas recirculation line (14) - in particular as exhaust manifold for several cylinders (2) - second intake manifold (10) opens , To avoid torque drops in the full load range, it is provided that the flow connection between the second intake manifold (10) and the total intake pipe (19) by a downstream of the second intake manifold (10) arranged - preferably controllable - shut-off valve (25) is closable.

Description

Description: The invention relates to an air intake system for an internal combustion engine, with an intake manifold arrangement which has at least one first intake manifold and at least one second intake manifold, at least one first individual intake line per cylinder from the first intake manifold and at least one second per cylinder from the second intake manifold Single intake line goes out, and wherein the first and the second intake line upstream of a transition opening for connection to a cylinder head combine to form an overall intake line, wherein at least one exhaust gas recirculation line opens into the second intake manifold, which is designed in particular as an exhaust manifold for multiple cylinders Flow connection between the second intake manifold and the entire intake line can be closed by a preferably controllable shut-off element arranged downstream of the second intake manifold.

At the beginning of each intake stroke of a piston internal combustion engine, a negative pressure wave is generated in the intake system, which propagates downstream in the intake system and is then reflected at the end of the system, either at the opening to the atmosphere or to a buffer tank. It is known to design the intake system in such a way that the positive pressure wave reaches the intake opening immediately before the intake valve closes, as a result of which additional intake air can be conveyed into the combustion chamber and the so-called charge level can be increased. Numerous intake systems are known in which an inertia or resonance effect of the intake air is used to increase the degree of charging. However, in these systems the period of oscillation of the pressure wave in the intake system can only be coordinated with the opening and closing frequency of the intake valve to achieve sufficient vibration charging within a limited speed range, which is determined by the shape of the intake line. For this reason, intake systems have already been proposed in which, for example, the length of the intake line can be changed as a function of the engine speed in order to obtain a vibration charging effect over a wider speed range.

DE 37 11 096 A1 describes an intake system for an internal combustion engine with a plurality of individual intake lines, each of which is connected to the cylinder with its downstream ends. A connecting line is provided for connecting the individual suction lines to one another and a flap valve is arranged at each connection point of the connecting line to the individual suction lines, which can be adjusted between a fully open position and a closed position by means of an actuating device. The actuating device actuates the flap valves depending on the operating state of the internal combustion engine.

From DE 198 00 079 B4 an air intake system for an internal combustion engine with an air collector is known, which is connected to the cylinders by means of individual intake lines. The air intake system also has a power collector that is common to all individual intake lines, which connects them to one another or shuts them off from the individual intake lines. A long single suction line starts from the air collector and a short single suction line starts from the power collector, whereby the two individual suction lines unite to form an overall suction line before entering the cylinder. The flow through the short individual suction lines can be regulated by means of a rotary valve.

The publications US 5,088,454 A and US 5,144,918 A show similar air intake systems for internal combustion engines with two differently long suction paths, between which can be switched by means of actuators.

[0006] JP 2014 224 509 A discloses an air intake system for an internal combustion engine with an intake manifold arrangement with a first intake manifold and a second intake manifold, each of which emanates from individual intake lines. An exhaust gas recirculation line opens into the second exhaust gas collector. For each cylinder, a first individual intake line originating from the first intake manifold and one from the second intake manifold unite

AT 520 737 B1 2019-07-15 Austrian

Patent office ler outgoing second individual intake line to a total intake line, which leads to the respective cylinder. The flow connection between the second intake manifold and the entire intake line can be closed by a shut-off element arranged downstream of the second intake manifold. Similar air intake systems are also known from EP 855 502 A2 or DE 30 11 580 A1 or DE 691 20 632 T2.

The US 5,005,553 A shows an internal combustion engine with an air intake system, which has a first and a second intake manifold. A flow path, which consists of a single suction line originating from the first suction manifold and a total suction line, has a U-shaped curved line area, the second suction manifold being arranged outside the first flow path with respect to the U-shaped curvature.

[0008] From AT 512 890 B1 an internal combustion engine with an exhaust system and an intake system is known, the intake system having an intake manifold. For exhaust gas recirculation, an EGR distributor strip for cylinder-selective exhaust gas recirculation is provided, into which an EGR flow path for recirculated exhaust gas opens. The EGR manifold is connected to the cylinder intake lines from the intake manifold. The recirculated exhaust gas is controlled via an exhaust gas control valve which is arranged upstream of the EGR distributor strip in the EGR flow path. Such arrangements have the disadvantage that gas dynamic effects are at least partially disturbed, in particular in the full-load range of the internal combustion engine, since the EGR distributor strip is permanently connected to the inlet lines. This adversely affects the maximum available torque and deteriorates the full load performance.

The object of the invention is to avoid torque drops in the full load range.

Starting from an air intake system of the type mentioned, this object is achieved in that the exhaust gas recirculation line opens centrally into the second intake manifold.

This central feedback has the advantage that there is a good uniform distribution of the recirculated exhaust gas between the cylinders and all cylinders are loaded evenly.

Particularly in the full load range, especially at low engine speeds, the shut-off element can block the flow connection between the second intake manifold and the entire intake line. This prevents gas-dynamic effects from being disturbed by the second intake manifold. Thus, the resonance behavior of the first intake manifold and the first individual intake line can be fully used, whereby the degree of filling and thus the torque in the full load range can be significantly improved. At higher speeds, however, the shut-off device is opened at full load, with a shortened resonance length then acting. The result of this is that the charge is increased at higher speeds, the exhaust gas recirculation valve remaining closed in this case, ie at full load.

[0013] The internal combustion engine has at least one cylinder and, in particular, is multi-cylinder. The second individual intake line of each cylinder can be shut off by a shut-off device. The second individual intake lines are opened or closed simultaneously by the shut-off devices.

In order to save components and space and to facilitate the control of the shut-off devices, it is advantageous if the shut-off device is formed by a rotary valve arrangement or a flap arrangement, the rotary valve arrangement or flap arrangement preferably being designed to control at least two second suction lines simultaneously.

An embodiment variant of the invention provides that in the exhaust gas recirculation line upstream of the second intake manifold, an exhaust gas control valve, preferably downstream 2/9

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Patent office is arranged an exhaust gas cooler. The amount of recirculated exhaust gas is thus controlled separately to shut off the second intake line. The shut-off device can thus have a simple open / close control with only two positions.

In order to achieve optimal gas dynamic effects, it is advantageous if the first individual suction line has a greater length than the second individual suction line. Optimal resonance behavior can be achieved if the second intake manifold is arranged adjacent to the first intake manifold.

The available space can be used as best as possible if a first flow path between the first intake manifold and the transfer opening, which consists of a first individual intake line and overall intake line, has a U-shaped curved line area, it being particularly advantageous if the second intake manifold and / or the second individual intake line - based on the U-shaped curvature of the line area - is arranged outside the first flow path and forms a second flow path which is connected to the first flow path in terms of flow.

Extremely effective resonance charging effects both in the low and in the higher engine speed range of the internal combustion engine can be achieved if the second individual suction line opens upstream of the U-shaped curved line area of the first flow path and thus combines the first and the second flow path. This has the advantage that a continuous flow is ensured and a stall in the U-shaped line area is avoided.

The invention is explained below with reference to the embodiment shown in the non-limiting figures.

1 shows an internal combustion engine with an air intake system according to the invention, [0022] FIG. 2 shows an air intake system according to the invention in a first embodiment variant in a side view and [0023] FIG. 3 shows an air intake system according to the invention in a top view.

1 schematically shows an internal combustion engine 1 with four cylinders 2, with an intake system 3, an exhaust system 4 with exhaust gas aftertreatment devices 5 and an exhaust gas recirculation system 6 for recirculating exhaust gases from the exhaust system 4 into the intake system 3.

The intake system 3 has an air intake system 7 with an intake manifold arrangement 8, which includes a first intake manifold 9 and a second intake manifold 10. The first intake manifold 9 is connected to an air line 11 which is common to all cylinders 2 and in which a throttle valve 12 is arranged. An air filter 13 is arranged in the air line 11 upstream of the throttle valve 12.

The exhaust gas recirculation system 6 has an exhaust gas recirculation line 14 branching off from the exhaust system 4 and opening into the second intake manifold 10, in which an exhaust gas cooler 15 and an exhaust gas control valve 16 are arranged.

The second intake manifold 10 is arranged not far from the first intake manifold 9, in particular adjacent to the first intake manifold 9.

The first 9 and the second intake manifold 10 extend in the longitudinal direction of the internal combustion engine 1 across all four exemplary cylinders 2. For each cylinder 2, the first intake manifold 9 has a first individual intake line 17 and the second intake manifold 10 has a second individual intake line 18. Before entering the respective cylinder 2, the first individual intake line 17 and the second individual intake line 18 combine to form an overall intake line 19. The overall intake line 19 has in the region of a connecting flange 20 for connection to a cylinder head 21 of the internal combustion engine 1 an over 3/9

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Patent office occurs opening 22.

The first intake manifold 9, the first individual intake line 17 and the overall intake line 19 form a first flow path P1 for the intake air for each cylinder 2. A second flow path P2, indicated by dashed lines in FIG. 2, for the recirculated exhaust gas and the intake air is formed by the second intake manifold 10, the second individual intake line 18 and the overall intake line 19. The first flow path P1 is connected in terms of flow to the second flow path P2 by this arrangement and is thus routed together in the overall intake line 19.

Each first flow path P1 has, per cylinder 2 between the first intake manifold 9 and the transition opening 22, a U-shaped curved line area 23, which is predominantly formed by the overall intake line 19. The second intake manifold 10 and the second individual intake lines 18 are arranged outside the first flow paths P1, with reference to the U-shaped curved line regions 23. Every second individual suction line 18 opens transversely at the beginning of the entire suction line 19 in front of the U-shaped curved line area 23, as shown in FIG. 2.

As is shown schematically in FIG. 2, a shut-off element 25, for example formed by a rotary slide valve arrangement or flap arrangement, is arranged in the area of the junction 24 of the first individual suction line 17 and the second individual suction line 18. With this controllable shut-off device 25 arranged downstream of the second intake manifold 10, the flow connection between the second intake manifold 10 and the overall intake line 19 can be interrupted. The flow connection through the shut-off device 25 is interrupted, for example, when there is a high load requirement or in the full load range of the internal combustion engine 1 at low speeds. The interruption prevents the volume of the second intake manifold 10, the second first individual intake line 18 and the exhaust gas recirculation line 14 from having a disadvantageous effect on the gas dynamic effects in the intake system. Loss of torque can thus be avoided.

If the exhaust gas recirculation is used, the exhaust gas control valve 16 in the exhaust gas recirculation line 14 and the shut-off element 25 are opened and the flow path between the second intake manifold 10 and the transfer opening 22 is established.

If the exhaust gas recirculation - for example in the torque range - is no longer used, the exhaust gas recirculation line 14 together with the second intake manifold 10 and the second individual intake lines 17 is decoupled by the shut-off element 25 and there is no more torque loss.

If, for example, high speed and high load are driven - ie without exhaust gas recirculation - the shut-off element 25 is open and the exhaust gas control valve 16 in the exhaust gas recirculation line 14 is closed. The second intake manifold 10 and the second individual intake line 17 thus provide an additional resonator volume, which is also used as an exhaust manifold for distributing the exhaust gas to the individual cylinders 2.

Fig. 3 shows an air intake system 7 with an intake manifold assembly 8, which has a first intake manifold 9 and a second intake manifold 10. The first intake manifold 9 is connected to an air line 11 which is common to all cylinders 2 and in which a throttle valve 12 is arranged. Starting from the first air collector 9, first individual suction lines 17 and total suction lines 19 lead to transfer openings 22 for connection to the cylinders.

The arranged above the first intake manifold 9 second intake manifold 10 is designed as a distributor for recirculated exhaust gas. The exhaust gas recirculation line 14 of the exhaust gas recirculation system 6 opens into the second intake manifold 10 centrally, that is to say centrally in relation to the longitudinal extent of the second intake manifold extending over several cylinders. Second individual intake lines 18 lead from the second intake manifold 10 to the total 4/9

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Suction lines 19, where they open at an acute angle and via oval inlet openings 26 and unite with the first individual suction line 17. The shut-off devices 25 are arranged between the second intake manifold 10 and the inlet openings 26, preferably in the region of the mouths into the overall intake lines, and can be adjusted between a closed and an open position by means of an actuator 28 via a common shaft 27.

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Patent Office

Claims (9)

claims 1. Air intake system (7) for an internal combustion engine (1), with an intake manifold arrangement (8) which has at least one first intake manifold (9) and at least one second intake manifold (10), with the first intake manifold (9) per cylinder (2) at least one first individual intake line (17) and at least one second individual intake line (18) for each cylinder (2) from the second intake manifold (10), and the first (17) and the second intake line (18) upstream of a transfer opening (22) for connection to a cylinder head (21) to form an overall intake line (19), at least one exhaust gas recirculation line (14) opening into the second intake manifold (10), which is designed in particular as an exhaust manifold for several cylinders (2), whereby the flow connection between the second intake manifold (10) and the entire intake line (19) through a preferably controllable shut-off device (25) arranged downstream of the second intake manifold (10) can be closed, characterized in that the exhaust gas recirculation line (14) opens centrally into the second intake manifold (10). 2. Air intake system (7) according to claim 1, characterized in that the shut-off element (25) is formed by a rotary valve arrangement or a flap arrangement. 3. Air intake system (7) according to claim 2, characterized in that the shut-off device (25) is designed to control at least two second intake lines (18) of two cylinders (2) simultaneously. 4. Air intake system (7) according to any one of claims 1 to 3, characterized in that an exhaust gas control valve (16), preferably downstream of an exhaust gas cooler (15), is arranged in the exhaust gas recirculation line (14) upstream of the second intake manifold (10). 5. Air intake system (7) according to one of claims 1 to 4, characterized in that the first individual intake line (17) has a greater length than the second individual intake line (18). 6. Air intake system (7) according to one of claims 1 to 5, characterized in that the second intake manifold (10) is arranged adjacent to the first intake manifold (9). 7. Air intake system (7) according to any one of claims 1 to 6, characterized in that a first flow path (P1) between the first intake manifold (9) and the transfer opening consisting of a first individual intake line (17) and a total intake line (19) (22) has a U-shaped curved line region (23). 8. Air intake system (7) according to claim 7, characterized in that the second intake manifold (10) and / or the second individual intake line (18) - based on the U-shaped curvature of the curved line region (23) - outside the first flow path (P1 ) is arranged. 9. Air intake system (7) according to claim 7 or 8, characterized in that the second individual intake line (18) opens upstream of the U-shaped curved line region (23) of the first flow path (P1).