DE102014003442A1 - Valve unit, such as exhaust flap unit for motor vehicles - Google Patents

Abstract

The invention relates to an exhaust system, in particular with an exhaust valve device, in particular for use in motor vehicles.

Description

The invention relates to a valve unit for combustion units, such as internal combustion engines, esp. For motor vehicles, consisting of a pipe section, a valve shaft mounted on this and immersed in this valve shaft, on which a pipe section located in the valve flap is provided and the flap shaft is operatively connected to an output shaft of a drive means to move the valve flap between two end positions, a maximum open position and a maximum closed position, back and forth.

In such exhaust valves, in particular when they are motor-driven, for example via a cable, a linkage or directly or indirectly with the interposition of a transmission (usually a worm gear) of an engine, such as a particular provided on the exhaust valve electric motor, it may happen that This actuator fails, either due to power failure or mechanical defects. If this happens in a closed or practically closed position of the valve flap, it comes first to an uncontrolled pressure increase, which can then lead to an uncontrolled Sillstand the prime mover with damage to the same or other components in the drive train, which in turn brings with it a risk of accidents, which can be dramatic especially with motorcycles. Here comes as a special risk nor the impact of splashing water in the region of the exhaust valve added, which is associated with a shock-like cooling of the hot exhaust pipe and can lead to Klappenklemmern. In order to reduce the effects of such caused by electrical or mechanical disturbances failures of the actuators, it is already known to provide emergency measures, so with the additional use of a capacitor which is to ensure by means of additional control in a power failure, a minimum opening angle of the valve. However, this means a considerable extra effort and it is also both such control means and such a capacitor itself susceptible to failure, especially since the exhaust system is the system with the largest vibration amplitudes in the drive train.

The present invention has for its object to eliminate the disadvantages of the previously known exhaust valve arrangements and to provide simple, inexpensive and safe measures for the operation of particular motor vehicles, which can be used in exhaust duct systems, eg. B. in connection with cylinder deactivation, exhaust gas recirculation, backpressure control, exhaust gas catalysts or to influence the combustion or exhaust noise. Also, there is still the possibility to influence the noise behavior.

This is achieved according to the invention in devices of the type mentioned by such an embodiment of the valve flap and / or associated pipe section that remains in the closed position between the inner contour of the pipe section and the valve flap a gap. Thus, in the "closed" position of the valve flap - also referred to as a diaphragm - a cross-sectional difference, or - seen in the flow direction - a difference of the effective areas of inner tube contour and valve flap, or a distance between the circumferential contours of the valve flap and the inner contour of opposite contours of the pipe section, to produce a targeted, predetermined leakage, which is greater than that guaranteed by the usual manufacturing tolerances resulting leakage and the at least still emergency running properties of the internal combustion engine.

This can be achieved according to an inventive feature in that the usually having at least a substantially circular cross-section valve flap and / or usually also has an at least substantially circular cross-section having a pipe section deviating from the circular cross-section (s). It may be the cross-section of the pipe section, as usual, have a circular cross-section and the aperture be at least approximately elliptical (or vice versa), wherein the large axis of the valve flap is aligned transversely to the flap shaft. The end position of the flap can be provided transversely to the longitudinal direction of the pipe section or defined before reaching the transverse position and by stopping the flap contours in the region of its longer semi-axis on the contours of the pipe, or it can be provided a separate stop. Such an embodiment in any case excludes the above-mentioned flap clamps and reliably ensures the existence of emergency running properties in the case of defects in the actuator, especially since this function guaranteed by the invention is not dependent on other units, but this function of the already existing components by the invention Design of the same is met.

However, a valve unit according to the invention can also be characterized in that the valve flap has at least one flattening, a cutout, a recess or the like at its outer circumference.

It is a special feature of the invention that the exhaust system in the field of Valve flap a predetermined, targeted leakage, and thus also has a targeted, predetermined leak that is greater than the already resulting from the usual manufacturing methods leakage or leakage and these are just chosen so that emergency running properties of the vehicle are guaranteed. Here, a minimum leakage, so a cross-sectional difference, or - seen in the flow direction - a difference between the surfaces of the inner tube and valve flap, or a distance between peripheral contours of the valve flap and the inner contour of opposite contours of the pipe section of up to 30%, preferably between 20-30%, particularly advantageously between 20 and 25%, but in particular be at least 5%.

Based on 1 to 4c Let the invention be explained in more detail:

It shows 1 the invention in connection with an exhaust flap in view,

2 the exhaust flap in a section gem. line II-II,

3 an enlarged section III 2 .

the 4a - 4c Another inventive design options of exhaust pipe and flap in a representation from the line IV-IV of 3 ,

The exhaust flap A is shown in the form of a prefabricated unit with an exhaust pipe 1 from a closed tube profile used in an exhaust system, eg. B. is welded. A lower and an upper bearing point 2 . 3 with bushings 2a . 3a and bearing elements received therein 4 . 5 serve for the storage of the valve flap shaft 6 , Both sockets are gas-tight with the pipe 1 connected, z. B. welded.

The warehouse 4 the lower depository 2a is a plain bearing with axial bearing function, what the shaft 6 with a bunch 6a against the lower end face of the bearing 4 is applied and under the action of an axial spring force.

The lower bearing point is gastight to the outside via a lid 7 completed.

A console 8th using U-thighs 8a on the pipe 1 is welded together, serves together with a holding plate attached thereto 9 for supporting the actuating means B, here a cable. A coil spring 10 On the one hand, it supports itself with one end 10a on an upwardly directed boom 9a of the retaining plate 9 off and on the other with their other end 10b on a down-facing boom 12a a lower disc 12 from. The disc 12 , the rotation with the shaft 6 connected together with a disk 13 on which it is attached, the pulley for the soul of the cable B.

The feather 10 is designed to be on the shaft 6 fastened valve flap holds in an open position when the cable is released by a drive motor accordingly. In this position, the spring urges the boom 12b the disc 12 against the effective as a stop boom 9b of the retaining plate 9 , The feather 10 , a compression spring, exerts over the disc 12 , the wave 6 and the bundle provided for this purpose 6a an axial bias on the end face of the bearing element 4 out.

The open position of the panel 11 , ie the resting position, is both in 1 as well as in 2 presented in a very excellent position. According to the 1 and 2 here is the aperture 11 opposite the pipe 2 flatter, namely elliptical. It has a deviating from the usually circular design, in the present embodiment, ie with the large semi-axis transverse to the valve shaft 6 arranged. Such a design is particularly, but not exclusively, advantageous in the context of damper actuators, in which - instead of the in 1 shown cable drive - an electric drive motor is used, which directly or indirectly the flap shaft 6 drives. Such drives can be designed to be self-locking and in which, if no energy for adjustment is required, the power is turned off to save energy. This drive motors can be self-locking for themselves, z. B braked or blocked od. Like. Or it may be a drive motor downstream unit, such as a transmission with self-locking, such as a worm gear, be provided in the power transmission. However, such drives have the disadvantage that in a power failure, when the panel is then just in or at least approximately closed position, the same can not be moved out of this position and the engine comes to an uncontrolled halt. This can occur especially in motorcycles even when closed Aperture yes, because it is located directly in the hot gas flow, faster and stronger thermal expansion experiences than the exhaust pipe - a shock-like cooling of the exhaust pipe takes place, such as by the action of water spray and thus jamming of the aperture occurs - especially on motorcycles with catastrophic consequences.

Out 1 it can be seen that in the closed position 11a Dashed line shown aperture 11 opposite the pipe 1 flatter, at least approximately elliptical, with its small half-axis in Direction of the wave 6 , is formed so that here even with unusual actuators nor a minimum throughput or a targeted leakage or leakage according to the passage at 14 , ie according to the difference of the effective areas of flap 11 and pipe 1 is guaranteed. It has been found that a minimum leakage of up to 30% may be appropriate, advantageously between 20-30%, more preferably between 20 and 25%, preferably between 10 and 20, but at least 5%.

But this effect can also be achieved by the tube and the flap or only the flap have a shape deviating from the circular shape and a targeted minimum leakage is provided therebetween, which is (clearly) above the resulting by the usual manufacturing tolerances column. The plant of the flap on the pipe in the closed valve position can then be done by stopping the same with at least one shaft further away.

According to IVa is the leakage generated by using a conventional, at least approximately circular aperture 11aa in a deviating from the circular cross-section, here elliptical and designed as a profile tube pipe section 1a an exhaust system. In special applications, it may also be advantageous to design both components, panel and pipe section, each having a different cross-section of the circular cross-section with a corresponding passage in the "closed" end position of the flap. But it may also - if necessary, regardless of whether in the most closed position of the valve over the beyond given by the tolerances leakage or an overflow loss of volume is present or not - be advantageous in certain applications, at least the pipe section of the exhaust valve unit and before and / or underlying areas of the exhaust pipe system also, and that over at least substantial longitudinal sections to design with a deviating from the circular cross-section, z. B. also in cramped space or space and for these sections also use profile tube.

According to a further inventive idea also - regardless of the use of exhaust valves - or even exhaust flaps spaced areas of the exhaust pipe system with a circular cross-section substantially, and deviating more than the usual tolerances cross-section, be configured and these sections of profile tube , z. Example of flat tube with at least approximately constant profile, which extend over longer portions of the exhaust pipe system than is the case in transition areas from one to another pipe profile or other pipe dimensions. It may also be advantageous to use this cross section deviating from the circular cross-section together with the valve flap before the end of the exhaust system, ie directly as Abgasanlagenende, even instead of a tailpipe, wherein the cross section of the end portion of the exhaust system, as well as the valve flap, so the entire optical Design of this area, the design of the vehicle and / or the desired noise behavior can be adjusted. This can also be advantageous in cases where previously several, z. B. two exhaust pipes open into a common tailpipe. Instead, the two exhaust system pipe ends can now be provided with a correspondingly designed aperture together with valve flap (s). Such inventive embodiments are described in the German patent application ... (own character K 0213), which is hereby incorporated in full in the present application.

The 4b and 4c show further design options for generating a targeted and predictable leakage in the most closed end position of the flaps 11b and 11c in housings 1b and 1c where the notches, cutouts, flats 11ba . 11bb . 11 bc or the like as a single profiling or more on the flap, even distributed unevenly, can be provided. To achieve this purpose but can also-optionally additionally- at least the corresponding, the diaphragm opposite pipe section have a corresponding bulge. Also, the aperture can be perforated accordingly.

In 3 that a section III of the 2 shows, is finally the design of the depository 3 explained in more detail. After inserting the shaft 6 together with the plain bearing 4 from below through the bushing 2a and with its upper portion through the bearing bush 3a and the insertion of the bearing body shown in dashed lines 5 that is relatively loose between shaft 6 and socket 3a is the same, by applying a predetermined force F z. B. compressed by means of an annular punch until it is the gray deposited form 5a has assumed and wherein a plastic material displacement is carried out and the bearing element 5 now both the wave 6 as well as the sleeve 3a seals and the shaft 6 is also stored. The degree of deformation is in addition to the pressure to be applied also determined by the axial path by which the bearing sleeve is compressed by the punch, both of which must be taken into account to ensure sufficient permanent deformation of here soft graphite reinforced with a wire mesh bearing body without endangering the cohesion of the bearing body.

Claims (8)

Valve unit, consisting of a pipe section, a valve shaft mounted on this and immersed in this valve shaft, on which a tubular valve flap is provided and the flap shaft is operatively connected to an output shaft of a drive means to the valve flap between an open position and a closed position back and forth to move, characterized in that in the closed position between the inner contour of the pipe section and the valve flap remains a gap. Valve unit, in particular according to claim 1, characterized in that the valve flap and / or the pipe section has a deviating from an at least substantially circular cross-section cross-section (s). Valve unit, in particular according to claim 1 or 2, characterized in that the valve flap is formed flat with respect to the tube. Valve unit, in particular according to one of claims 1 to 3, characterized in that the valve flap is at least approximately elliptical. Valve unit, in particular according to one of claims 1 to 4, characterized in that the large semi-axis of the valve flap is aligned at least approximately transversely to the flap shaft. Valve unit, in particular according to one of claims 1 to 5, characterized in that the valve flap at its outer periphery at least one flattening, a cutout, a recess od. Like. Has. Exhaust system using a valve unit, in particular according to one of claims 1 to 6, characterized in that the exhaust system in the region of the valve flap has a predetermined, targeted leakage, which is greater than the leakage produced by the usual manufacturing methods. Exhaust system using a valve unit, in particular according to one of claims 1 to 7, characterized in that the exhaust system in the region of the valve flap has a predetermined, targeted leakage, which is greater than the resulting by the usual manufacturing methods or tolerances leakage.

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