DE202021003282U1 - Reflective silencer with 360° scene control - Google Patents

Abstract

Reflection silencer with a tunable path length and adjustable back pressure, characterized in that the path length is determined by a tuning tube that is immersed to an adjustable depth and the back pressure is determined by a rotating link at the outlet.

Description

BACKGROUND OF THE INVENTION

In the case of 4-stroke motorcycles with a high cylinder volume, an overall noise is required that conveys the "beefy" character of the machine, even when complying with noise protection regulations. The exhaust noise is the decisive component here.

Absorption silencers, which direct exhaust gases, e.g. through a perforated cylinder into an "acoustic sump" through surrounding insulating materials such as glass or metal wool, cause "blunt" noise emissions and, in extreme cases, "sewing machine noise".

With "Big Bikes", however, a rather rumbling, deep fundamental tone is expected, with clicking overtones that correspond to the vibrations felt on a heavy machine.

This sound cannot be achieved with the absorption dampers. Here, detour sound dampers (also called reflection dampers) are used, in which the feedback of the acoustic shock waves causes a cancellation of sound peaks by recoupling in front of the outlet.

This means that a sound level that is limited in terms of measurement technology can be combined with the impression of massive power development.

The crux of the matter, however, is that the phase cancellation is frequency-selective depending on the sound path and the speed of the engine, so that the proportions of the direct and deflected exhaust blast must be matched at predetermined speeds in order to generate a specific sound pattern that is suitable for the respective machine should be distinctive.

This is usually caused by adapted restriction of the transition from the manifold outlet to a tailpipe to the sound outlet.

However, the individual biker often has individual preferences and intentions and wants modifications, even if these sometimes tend to worsen the performance of the machine compared to the factory setting.

There are therefore a large number of retrofittable exhaust systems that change the sound of a machine within the scope of the approval limits - and in some cases beyond.

In order to allow variations here, silencers are often equipped with adjusting elements to modify the sound path. In the simplest form, this is a valve flap that closes or opens the detour into the bypass or enables a middle position.

Apart from the fact that these, with the euphemistic designation of an additional "racing setting", suggest the rule-compliant execution in the normal position and the admissibility of such modifications, the aim of such measures is to be able to create a "pithy" or "beefy" sound individually, and this as far as possible within the allowable limits.

OBJECT OF THE INVENTION

The object of the present invention is therefore to enable an individual adjustment of the exhaust system without violating the rules.

STATE OF THE ART

In addition to a large number of absorption silencers for motorcycles, such as U.S. 8,256,569 B1 , are reflection silencers, known for internal combustion engines since the 1970s, e.g U.S. 3,842,940 and SU 1694 944 A1 , later in connection with catalytic emission control; eg under JP 200 529 099 3A and under contract; Usage of the Helmholtz resonator effect under JPH0640319U.

From 1990, these were also used for motorcycles, albeit initially in combination with absorption damping as in JP 2009 041 562A and, although not explicitly described for motorcycles, under CN 10 877 9692B and CN 110 735 689A , such as CN 2012 025 13Y , as well as dedicated for racing vehicles under CN 11 2081642A .

EP1099829 already describes such a system with reflection damping in the beginning, although the restriction of the passage from the main pipe into the expansion pipe is determined by the diameter of its perforations and is therefore not changeable.

DE 10 2009 036 559 A1 does it similarly. however, complements it with a restriction backdrop at the end of the primary tube, too U.S. 7,484,591 B2 , the previous patent by the same inventor, uses a variable baffle plate to control the gas flows in the main pipe. However, such valve devices in the exhaust system of internal combustion engines tend to quickly become sooty and then jam in the case of rotatable links.

SOLUTION

The basic solution for this is the combination of a partial closure of the main path of the exhaust gases via the circular surface of the outer tube with tuning through variable immersion depth of the tuning tube, which determines the path length of the sound passing through and thus the frequency range of the primary noise cancellation.

A restriction link at the end of the primary pipe affects the volume of the bypass and thus the intensity of the damping. According to the invention, their design is such that a rotatable connecting link disk is designed behind an inlet disk of the same size with a double slot rounded on both sides, the overlap of which determines the passage.

The adjustability over a rotation angle of 360° has the effect that sooting on the connecting discs shears off in the other disc area due to "over-tightening", burning in the gas flow and thus being eliminated.

Both can be dynamically tuned in such a way that, depending on both parameters - the immersion depth of the tuning tube, which primarily determines the frequency range of the cancellation, as well as the back pressure due to the shutter angle and thus the permeability of the congestion backdrop, which determines the intensity of the cancellation. Thus, the damping in different frequency ranges and thus the "sound" of the machine can be determined.

In the simplest case, the backdrop as well as the immersion depth of the tube can be adjusted manually, but this only selects one sound characteristic.

However, an electronically controlled setting can be designed in such a way that, for example, a sound that has been evaluated as positive for certain speeds is achieved - e.g. dark bubbling when stationary, then rumbling and aggressive sawing at high speeds.

This is done by controlling the tuning tube, e.g. with the help of a toothed rack and a small servo motor, on the side of the outlet restriction by rotating the widely adjustable storage gate with several, specifically permeable discs.

An inventive step towards this is to avoid their sooting by designing the guide and blocking element of the connecting link as discs with two radially symmetrical elongated holes and thereby making the blocking element rotatable in both directions or rotatable by 360°.

In the event of jamming, the connecting link can be released again by turning it in the opposite direction. In addition, the setting range for the combination with the path length adjustment is larger.

character list

• 1 zeigt den Innenrohrkranz (1)
• 2 zeigt Feststehenden Ring mit Langloch(2)
• 3 zeigt den losen Ring mit Langloch (3)
• 4 zeigt den Käfig (4) mit vier Innenfedern (8) mit Rastkugeln (9)
• 5 zeigt den Adapter-Ring mit Langloch (5)
• 6 zeigt den Feststehenden Innenring (6)
• 7 zeigt die Adapter Endkappe mit Langloch (7)
• 8a zeigt den in den Käfig (4) integrierte losen Ring mit Langloch (3) sowie vier Innenfedern (8) mit Rastkugeln (9) in Position.
• 8b zeigt die Anordnung der Bauteile zueinander.

Assuming that the basic design of such dampers is known, the representation in the following figures is limited to the novelty

• 1 shows the inner tube wreath (1)
• 2 shows fixed ring with slot(2)
• 3 shows the loose ring with slot (3)
• 4 shows the cage (4) with four inner springs (8) with detent balls (9)
• 5 shows the adapter ring with slot (5)
• 6 shows the stationary inner ring (6)
• 7 shows the adapter end cap with elongated hole (7)
• 8a shows the loose ring with slot (3) integrated into the cage (4) and four inner springs (8) with locking balls (9) in position.
• 8b shows the arrangement of the components in relation to one another.

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US8256569B1 [0013]
• US3842940 [0013]
• SU 1694944 A1 [0013]
• JP2005290993A [0013]
• JP2009041562A [0014]
• CN 108779692B [0014]
• CN 110735689A [0014]
• CN201202513Y[0014]
• CN 112081642A [0014]
• EP 1099829 [0015]
• DE 102009036559 A1 [0016]
• US7484591B2 [0016]

Claims (8)

Reflection silencer with a tunable path length and adjustable back pressure, characterized in that the path length is determined by a tuning tube that is immersed to an adjustable depth and the back pressure is determined by a rotating link at the outlet. reflection silencer claim 1 , characterized in that the rotating link consists of 2 or more discs with radial slots. reflection silencer claim 2 , characterized in that depending on the rotational position overlapping connecting discs determine passage and dynamic pressure. reflection silencer claim 1 - 3 , characterized in that the slotted discs can be rotated through 360°. reflection silencer claim 4 , characterized in that the rotation of the discs is adjustable by one or more servomotors. reflection silencer claim 1 , characterized in that the tuning tube can be moved in or out of the muffler with a changing immersion depth. reflection silencer claim 6 , characterized in that the immersion depth is controlled by a servomotor with a threaded spindle. reflection silencer claim 1 , characterized in that the parameters of the dynamic pressure adjustment and the adjustment of the path length are program-controlled as a function of the speed of the motor.

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