WO2004090304A1

WO2004090304A1 - Switching unit in the intake system of a reciprocating piston combustion engine

Info

Publication number: WO2004090304A1
Application number: PCT/AT2004/000121
Authority: WO
Inventors: Peter Steinrück; Bernhard Spiegl
Original assignee: Hoerbiger Valvetec Gmbh
Priority date: 2003-04-09
Filing date: 2004-04-07
Publication date: 2004-10-21
Also published as: ATA5492003A; AT412987B

Abstract

In order to enable a pulse charging that improves the torque curve, the intake system (1) of a reciprocating piston combustion engine (2) is provided with a switching unit comprising a shut-off element (8), which is connected upstream from the combustion chamber-side controlled intake opening (6), and which, in an independently controllable manner, occludes the intake line (3) by displacing, during a partial range of the working cycle, switching elements (9, 10) relative to one another, said switching elements having flow-through openings (14, 14', 14'', 22, 22') and blocking surfaces (16). The switching elements (9, 10) consist of a fixed sealing plate (12, 12') with a large number of flow-through openings (14, 14'') and of a blocking plate (15, 15', 15''), which can be displaced parallel to the sealing surface (13) of the sealing plate (12, 12') and which has a corresponding large number of blocking surfaces (16) that close the flow-through opening (14, 14'') of the sealing plate (12, 12') in one switching position and open it in another switching position. The flow channels (17) in the sealing plate (12, 12') and blocking plate (15, 15', 15'') are formed by channel walls (18) that extend continuously and in a manner that promotes flowing. This enables a simple and rapid switching from the open position, which virtually does not inhibit the flow-through, to the closing position.

Description

Switch unit in the intake system of a reciprocating piston internal combustion engine

The invention relates to a switching unit in the intake system of a reciprocating internal combustion engine, with an upstream of the combustion chamber-controlled inlet opening, the inlet line by elatiwerschieb of flow openings and blocking surfaces having switching elements in a portion of the cycle independently controllable closing shut-off device.

Switching units of this type are known and enable so-called pulse charging and also load control of reciprocating piston internal combustion engines. By means of the additional shut-off device in the inlet line, which closes or releases the inlet cross-section extremely quickly at certain times during the suction stroke, considerable torque increases can be achieved over the entire usable speed range of the internal combustion engine - but especially at low engine speeds.

In the case of reciprocating piston internal combustion engines, the aim is usually to achieve the most uniform, high torque characteristic possible from idling to high speeds, but this can only be approximated with great effort, since due to the resonance behavior of the inflowing charge quantity in the inlet line, most of the measures for optimizing the torque only in one very limited speed band effect. Naturally aspirated engines are operated with variable intake manifold lengths or resonance flap systems in the intake manifold in order to keep the torque characteristic as high as possible up to the partial load range. Another known possibility for increasing the torque is represented by variable valve trains for the intake valves, by means of which the valve timing can be shifted to optimize the gas exchange. Another means of increasing torque, which is mostly used in diesel engines, is exhaust gas turbochargers or mechanical superchargers, with which additional air or an ignitable mixture is conveyed into the combustion chamber, but pronounced torque weaknesses still remain below certain speed limits.

The concept of pulse charging already mentioned at the beginning enables, at least theoretically, the nominal torque of the engine to be maintained down to idling speed without resonance flap variation in the intake line, it being particularly advantageous that the increased air or mixture mass required in the event of a sudden increase in load with extremely short response or delay times in the combustion chamber is available.

The basic idea of this pulse charging lies in influencing the incoming charge through an inlet opening controlled upstream of the combustion chamber side (i.e. the inlet valve or the inlet opening controlled by the piston or the like). arranged independent shut-off device, by means of which the load can be measured as required or increased compared to natural suction. A so-called dynamic charging is achieved in that the opening and closing processes of this additional shut-off device can be controlled depending on the operating parameters of the engine and relative to the movement of the inlet valve and piston. Through the additional shut-off device, the actual start of intake can be delayed with respect to the opening of the intake valve, which can increase the charge, especially at low engine speeds, because by delaying the opening of the additional shut-off device after opening the intake valve, the first in the intake port between the additional shut-off device and the inlet valve, the charge located in the previous work cycle expands into the combustion chamber, whereupon a vacuum is created as a result of the increase in volume caused by the piston movement. The pressure difference in front of and behind the additional shut-off device leads to a correspondingly high flow rate of the charge then flowing into the combustion chamber after it has opened. This flow rate is braked towards the end of the piston stroke, as a result of which a dynamic pressure increase in the cylinder takes place before the inlet valve closes. The backflow of charge from the combustion chamber is then prevented by timely closing the additional shut-off element, which, as mentioned, after the closing of the inlet valve for the next work cycle, increased pressure remains between the inlet valve and the additional shut-off element.

Known arrangements with such additional shut-off devices (see, for example, DE 2938118 AI, DE 3737826 AI or also WO 00/03131) have the disadvantage that the relatively large masses to be moved over relatively long switching paths with the required, extremely short switching times between completely open and tight locked state (in the range of about 1 ms) require very complex and therefore fault-prone drive and control concepts that quickly cancel out the achievable advantages.

The object of the present invention is to improve a switching unit of the type mentioned at the outset in such a way that the disadvantages of the known arrangements of this type are avoided and that, in particular with structurally simple and reliable means, precise control of the additional shut-off element in the inlet line is possible.

This object is achieved in accordance with the present invention in a switching unit of the type mentioned in the introduction in that the shut-off element as switching elements is a sealing plate fixed in the flow path with a multiplicity of flow openings formed on a sealing surface and an immediately adjacent one parallel to the sealing surface of the Sealing plate displaceable blocking plate with a corresponding plurality of blocking surfaces that close the throughflow openings of the sealing plate in one switching position and release in another switching position, and that flow channels proceeding from the throughflow openings with continuously and streamlined channel walls in the sealing plate and in the areas of the blocking plates free of blocking surfaces Lock plate are provided. The sealing or blocking plates, which are thus adjacent to one another in the manner of gratings with complementary throughflow openings or blocking surfaces, offer the largest possible free throughflow surface in the open state of the shutoff element, so that a pressure drop in the charge flowing in the inlet line is avoided as far as possible. Due to the large number of individual flow openings, the actual switching path between the two switching positions - "open" on the one hand and "closed" on the other - can be drastically reduced in a very simple and effective manner, for example compared to the rotary or roller valves known from the prior art mentioned at the beginning, which has very advantageous effects with regard to the shortest possible switching times with the least possible stress on the switching elements and the changeover drive. As a result of the channels that flow from the flow-through openings of the sealing plate and from the corresponding channels that run from the blocking-surface-free areas of the blocking plate, the flow can be influenced as little as possible in the area of the shut-off element, which overall enables very precise and nevertheless robust control of the charge flowing in the inlet system or necessary exact influence on the vibrations of the charge column in the inlet system allows.

In a further preferred embodiment of the invention, it is provided that the cross-sectional area of each of the flow channels gradually decreases slightly along the flow path, so that flow separation and flow losses caused thereby are further reduced in the area of the shut-off element.

According to a preferred further embodiment of the invention, it can also be provided that the entire cross section of the flow channels in the narrowest cross section essentially corresponds to the inlet and outlet cross section of the inlet line in front of and behind the switching unit. Together with the configurations of the flow channels already described, the effect of the opened switching unit on the flowing charge can thus be kept as low as possible.

In a further preferred embodiment of the invention, on the side of the relatively displaceable locking plate opposite the sealing plate, there is a fixed guide plate with flow openings corresponding to the sealing plate and, in the open state of the shut-off element, flow channels with a total of continuous flow and flow. conveniently running channel walls provided. This means that the locking plate, which is slidable for switching, can be made relatively thin, the relatively long, flow-optimized flow channels required to ensure the undisturbed flow through the shut-off element in the open state being formed in the fixed plates (sealing plate and guide plate) provided on both sides. Thus, the displaceable locking plate can also consist, for example, of plastic and in any case be designed with a very small mass to be moved for switching, so that the accelerations and decelerations of the displaceable locking plate required for the short switching times can be achieved with low drive energy or braking or impact energy ,

In a particularly preferred further embodiment of the invention it is provided that the locking plate can be moved electromagnetically or electromotively between the two switching positions and is preferably in the open switching position when de-energized. This enables a simple and precisely controlled switching drive, the open switching position also being able to be held, for example, by one or more tension or compression springs.

According to another advantageous embodiment of the invention, the locking plate can be lifted off the sealing surface of the sealing plate by means of a lifting device, preferably an electromagnet, and thus before the movement into the other switching position. Thus, the friction between the displaceable locking plate and the fixed sealing plate itself can be practically completely avoided during the switching movement, which enables a further reduction in the drive energy to be used or an increase in the switching speed with reduced wear.

In a particularly preferred further embodiment of the invention, it is provided that the throughflow openings in the direction of the displacement of the locking plate have a significantly smaller dimension than transversely thereto, which in the simplest way brings a corresponding further shortening of the necessary switching paths while increasing the advantages already mentioned in this regard.

In a particularly preferred further embodiment of the invention, the throughflow openings are designed as radially aligned slots in the essentially disk-shaped sealing or guide plate, which correspond in the opened state of the shut-off element with corresponding flow channels of the likewise disk-shaped blocking plate which can be rotated between the two switching positions. A type of rotary slide valve is thus created, which, however, for switching over from one to the other switching position only essentially by the width of the throughflow openings in the circumferential direction certain short switching paths (jerky either by a small angle back and forth or continuously in the manner of a stepper motor drive) must be carried out, which enables simple and precise control of the charge flowing in the intake system to achieve the aforementioned advantages of pulse charging.

In a preferred further embodiment of the invention, the housing of the switching unit can be designed as a barrel-like extension of the flow path in the inlet line and, centrally as a narrowing of the streamlined free flow path, can carry the housing of the movement arrangement of the locking plate, with a hub-like carrier for the fixed part on the housing of the movement arrangement Sealing or guide plate and the movable locking plate is formed. This enables a structurally simple design of the switching unit that can be integrated relatively easily into the intake system of the internal combustion engine.

The invention is explained in more detail below on the basis of the exemplary embodiments shown schematically in the drawing. 1 shows a schematic partial section through a reciprocating piston internal combustion engine in the area of the intake system equipped with a switching unit according to the invention, FIG. 2 shows the enlarged detail of the switching unit from FIG. 1 in another switching position, FIG. 3 shows the locking plate from the in the 4 and 5 in a representation similar to FIG. 2, another embodiment of a switching unit according to the invention, FIG. 6 the partial development of a longitudinal section along the line VI-VI in FIG. 7, showing a longitudinal section through a further embodiment of a switching unit according to the invention, Fig. 8 shows the partial cross section along the line VIII-VIII in Fig. 7 and Fig. 9 and 10 schematic sections along the line XX in Fig. 7 in different switching positions of the switching unit.

1 is in the intake system 1 of a reciprocating piston internal combustion engine 2, only shown symbolically - in the inlet line 3 between an inlet opening 6 controlled on the side of the combustion chamber 4 by means of a poppet valve 5 and the inlet manifold 7 - the inlet line 3 in a partial area of the working cycle independently of the poppet valve 5 controllably closing shut-off device 8 is arranged. According to a more detailed representation of various embodiments in FIGS. 2 to 10, as switching elements 9, 10, a sealing plate 12 fixed in the flow path (arrow 11) with a plurality of through-openings 14 formed on a sealing surface 13 and an immediately adjacent one parallel to the sealing surface 13 of the sealing plate 12 displaceable blocking plate 15 with a corresponding plurality of blocking surfaces 16 closing the throughflow openings 14 of the sealing plate 12 in one switching position and releasing in another switching position. Starting from the flow-through openings 14 are in the open switch position according to FIG Fig. 1 - continuous flow channels 17 with steadily and streamlined channel walls 18 provided in the sealing plate 12 and in the areas of the blocking plate 15 free of blocking surfaces 16 - their entire cross section along the flow path essentially always the inlet and outlet cross section of the inlet line 3 before and corresponds behind the switching unit according to the invention. The cross-sectional area of each of the flow channels 17 can steadily decrease slightly along the flow path (in the direction of arrow 11), thus avoiding flow separation on the channel walls 18.

The locking plate 15 can be moved by means of an electromagnet 19 against the force of a spring 20 from the open position shown in FIG. 1 to the closed position shown in FIG. 2 and is therefore de-energized in the open switching position according to FIG. 1, which means that the entire switching unit is included Power failure remains ineffective and practically does not affect the normal function of the internal combustion engine.

3 to 5, a stationary guide plate 21 with flow openings 14 'corresponding to the sealing plate 12 and in the open state (according to FIG. 4) is on the side of the blocking plate 15' which can be made relatively thin on the sealing plate 12. of the shut-off element 8, a total of continuous flow channels 17 with channel walls 18 that run continuously and in an aerodynamically favorable manner. The mass of the locking plate 15 'to be moved between the open switching position according to FIG. 4 and the closed switching position according to FIG. 5 can be drastically reduced compared to the locking plate 15 (FIGS. 1 and 2) which is relatively thick due to the necessary flow channels 17, which is significant places lower demands on the electromagnet 19 or on any movement end stops and the like, and thus greatly accommodates the implementation of the shortest possible switching times with simple and reliable means.

3 shows a blocking plate 15 'as an example, the flow openings 22 corresponding to the flow openings 14 and 14' of the sealing plate 12 and guide plate 21 are divided over the length for reasons of strength. While the specific position, size and arrangement of the flow openings 14, 14 'and 22 is arbitrary within wide limits or can simply be chosen so that a flow cross section corresponding to the inlet or outlet cross section of the inlet line 3 is ensured, the flow openings have but in the direction of the displacement of the locking plate in a particularly advantageous manner a much smaller dimension than transverse to it, which allows short switching paths with a correspondingly positive influence on the overall construction. 4 and 5, the guide plate 21, which is fixed in the direction of the switching movement of the locking plate 15 ', can be moved to a small extent perpendicular to the sealing surface 13 and is pressed against the locking plate 15' in the direction of the sealing plate 12 by means of springs 23 in order to support the sealing action. Instead of this constant - and thus during the switching movement of the locking plate 15 'also increasing the friction of the same on the sealing plate 12 and the guide plate 21 - force action on the guide plate 21 could also be a switchable action, for example via clocked switchable electromagnets instead of the springs 23, whereby over a corresponding construction or arrangement could then easily be ensured that the locking plate 15 'has a slight play to the sealing plate 12 and the guide plate 21 during the switching movement.

While the relative displacement of the throughflow openings 14, 14 'and the blocking surfaces 16 or the throughflow openings 22 in the exemplary embodiments according to FIGS. 1 to 5 takes place linearly back and forth, in the exemplary embodiment according to FIGS. 6 to 10 it is provided that the throughflow openings 14 "or 22 'are formed as radially aligned slots in the essentially disk-shaped sealing plate 12' or guide plate 21 ', which in the open state (shown in FIG. 6 above or FIG. 10) of the shut-off element with corresponding flow channels or Flow openings of the likewise disc-shaped and rotatable between the two switching positions blocking plate 15 "correspond. The housing 24 of the switching unit is designed as a barrel-like extension of the flow path in the inlet line 3 and carries the housing 25 of the movement arrangement 26 of the blocking plate 15 "centrally as a restriction of the aerodynamically designed free flow path. On the housing 25 of the movement arrangement 26 there is a hub-like carrier 27 for the fixed sealing plate 12 ', the likewise fixed guide plate 21' and the movable locking plate 15 "are formed. Overall, the inner and outer flow restriction and the arrangement of the individual flow channels 17, which can also be seen specifically in FIG. 10, is designed such that the entire cross section of the flow channels is essentially always (and at least in the narrowest cross section) the inlet and outlet cross section of the inlet line 3 before and behind the switching unit.

The flow channels 17 or the flow openings 14 "and 22 'are thus arranged in a radial division or orientation in this embodiment. The relatively displaceable locking plate 15" is essentially designed as a disk which can be rotated about the central axis 28 and whose drive is via a special, at least two-pole electric motor 29 takes place. The center position of the two pole pairs 30 and 31 of the electric motor 29 can be offset according to FIG. 8 by the switching angle 32, that is half the pitch angle of the flow channels 17 according to FIG. 10, which is one when a pole pair is designed as a permanent magnet currentless preferred position of the arrangement, preferably in the open state, results. When the other pole pair is energized, the rotor 33 of the electric motor 29 rigidly connected to the blocking plate 15 ″ is rotated by the switching angle 32.

The bearing of the rotor 33 is designed according to FIG. 7 so that the two bearings 34, 35 enable precise radial guidance of the rotor 33, but at the same time allow longitudinal play, which is illustrated, for example, by the design of the bearing 35 as an angular contact ball bearing (or as Tapered roller bearings or the like) is possible. In the embodiment shown, this bearing 35 also absorbs axial forces in the flow direction (arrow 11).

In the stator 36 of the electric motor 29, a lifting magnet 37 is integrated, which can exert a force directed against the direction of flow (arrow 11) on the rotor 33 when the current is applied accordingly.

The following function of the switching unit can thus be implemented:

1 in front of the inlet valve of an internal combustion engine, not shown here, is closed at the beginning of the intake stroke, that is, the lock plate 15, which can be rotated about the central axis 28, closes the flow channels 17 according to FIG. 9. The lifting magnet 37 is there so excited that he overcomes the forces caused by the suction from the inlet opening of the internal combustion engine, acting on the locking plate 15 "and pulls the locking plate 15" firmly and tightly onto the sealing surface 13 of the sealing plate 12 '.

To open the shut-off element 8, the power supply to the lifting magnet 37 is first switched off, so that the compressive forces acting on the locking plate 15 "release it from the sealing plate 12 '. The minimal axial movement of the rotor 33 including locking plate 15" thus initiated is limited by the bearing 35 , By applying a magnetization directed against the permanent magnet in one pole pair (30 or 31) and a corresponding magnetization in the other pole pair, the switchover to the open position shown in FIG. 10 now takes place. Either a suitably designed stop can be provided for limiting the initiated rotary movement, or the locking plate 15 "can be positioned exclusively via the electromagnetically applied moments. Because of the small angle of rotation for the changeover and the low mass of the locking plate 15", both are also no problem with short switching times.

To close the shut-off element 8, the energization of the two pole pairs 30, 31 is reversed again and, after reaching the closed position (FIG. 9), the lifting magnet 37 is reactivated and the blocking plate 15 "is thus pulled back onto the sealing surface 13 of the sealing plate 12 ' in the pulse charging process described above, usually for the Duration of the compression and working stroke of the internal combustion engine between the inlet valve and the additional shut-off device, an overpressure is locked, the pressing of the locking plate 15 "to the sealing plate 12 'also takes place automatically or supported by the differential pressure applied to the locking plate 15", thus magnetizing of the solenoid 37 can also be omitted for the duration of these two cycles.

claims:

Claims

claims:

1. Switching unit in the inlet system (1) of a reciprocating piston internal combustion engine (2), with an inlet opening (6) controlled upstream of the combustion chamber, the inlet line (3) by relative displacement of flow openings (14, 14 ', 14 ", 22, 22') and blocking surfaces (16) having switching elements (9, 10) in a partial region of the work cycle, which independently lockable shut-off device (8), characterized in that the shut-off device (8) as switching elements (9, 10) has a sealing plate (12, 12 ') fixed in the flow path ) with a plurality of flow openings (14, 14 ") formed on a sealing surface (13) and an immediately adjacent blocking plate (15, 15 ', 15") which can be displaced parallel to the sealing surface (13) of the sealing plate (12, 12') one of the flow openings (14, 14 ") of the sealing plate (12, 12 ') which closes in one switching position and releases in another switching position a corresponding plurality of blocking surfaces (16 ), and that from the flow openings (14, 14 ', 14 ", 22, 22') continuous flow channels (17) with continuous and streamlined channel walls (18) in the sealing plate (12, 12 ') and in the Barrier areas (16) free areas of the locking plate (15, 15 ', 15 ") are provided.

2. Switching unit according to claim 1, characterized in that the cross-sectional area of each of the flow channels (17) along the flow path (arrow 11) decreases continuously slightly.

3. Switching unit according to claim 1 or 2, characterized in that the entire cross section of the flow channels (17) in the narrowest cross section essentially corresponds to the inlet and outlet cross section of the inlet line (3) before and after the switching unit.

4. Switching unit according to one of claims 1 to 3, characterized in that on the sealing plate (12 ') opposite side of the displaceable locking plate (15', 15 ") a fixed guide plate (21, 21 ') with the sealing plate (12' ) corresponding flow openings (14 ', 22') and in the open state of the shut-off element (8) a total of continuous flow channels (17) with continuously and streamlined channel walls (18) is provided.

5. Switching unit according to one or more of claims 1 to 4, characterized in that the locking plate (15, 15 ', 15 ") electromagnetically or electromotively between the is movable in both switch positions and is preferably de-energized in the open switch position.

6. Switching unit according to claim 5, characterized in that the locking plate (15 ") with a lifting device, preferably an electromagnet (37), is in communication and before the movement into the other switching position of the sealing surface (13) of the sealing plate (12th ') can be lifted off.

7. Switching unit according to one or more of claims 1 to 6, characterized in that the through-flow openings (14, 14 ', 14 ", 22, 22') in the direction of the displacement of the locking plate (15, 15 ', 15") are essential have a smaller dimension than transverse to it.

8. Switching unit according to one or more of claims 1 to 7, characterized in that the flow openings (15 ") are designed as radially aligned slots in the substantially disk-shaped sealing or guide plate (12 ', 21') which in The opened state of the shut-off element (8) corresponds to corresponding flow channels of the locking plate (15 "), which is also disk-shaped and rotatable between the two switching positions.

9. Switching unit according to claim 8, characterized in that the housing (24) of the switching unit is designed as a barrel-like extension of the flow path in the inlet line (3) and centrally as a narrowing of the aerodynamically designed free flow path, the housing (25) of the movement arrangement of the locking plate ( 15 "), a hub-like carrier (27) for the fixed sealing or guide plate (12 ', 21') and the movable locking plate (15") being formed on the housing (25) of the movement arrangement.