MXPA98009935A - Device of circulation of a - Google Patents

Abstract

The present invention relates to an air suction arrangement for a post-connected equipment, of the type in which adjustment devices are arranged in the area of the air circulation path to vary the circulation geometry for the circulating air , which is characterized in that the total cross section of the air circulation path is subdivided into individual air circulation channels and the air circulation paths in the different circulation channels can be governed by the adjustment devices to influence the length affective and the effective cross section of the air suction arrangement in its totalid

Description

AIR CIRCULATION DEVICE The present invention relates to an air circulation arrangement for an equipment, for example an internal combustion engine, which requires a certain air flow for its operation, according to the exordium of claim 1 and the subordinate claim 6. In order to achieve optimum performance in internal combustion engines known for automotive vehicles, suction systems are preferred, which have variable suction lengths and which consequently allow adaptation to the different operating requirements of the vehicle. motor. In this case, noise attenuation also plays an important role. By way of example, an air suction device for an internal combustion engine of German Patent DE-OS 40 41 786 is already known, in which a controllable clamping member provided for varying the opening is provided. through which the aspirated air circulates The closing member is located in a transverse channel disposed between two suction channels, said closing member being open or closed by means of control signals generated by an electronic control circuit. of control depend on the number of revolutions of the combustion engine and the temperature of the outside air, which is determined by means of a temperature sensor. "To achieve an improvement of the performance in the process of energy transformation _ of an engine of internal combustion for a range of operation that is well below the rated power of the engine and consequently a decrease in combustion In connection with the distance traveled, a selective disconnection of certain cylinders in the internal combustion engine is frequently carried out. In addition to the usual positioning of the throttle valve to control engine torque, the number of active cylinders can also be decreased. The cylinders that do not contribute to the moment. they are mechanically driven, but they are not fed with fuel. In the case of such cylinder disconnection, the pulsation of the aspirated air is also modified. A typical application of this cylinder disconnection is the reversal of a 6-cylinder internal combustion engine from 6-cylinder operation to 3-cylinder operation. Although each suction pulse caused by each one of these cylinders does not vary in the suction device seen by itself, the 6-cylinder cyclic operation causes another trajectory in the pulsation curve than in the case of 3-cylinders. . In this case the low sounds of snoring are particularly disturbing; these low-tone components can only be reduced by costly sound attenuators by reflection (for example Helmho tz resonators) taking into account the small constructive space available in a motor vehicle. However, for many other application cases, the resonance behavior of the suction arrangement is of paramount importance, the critical space often also representing the available space. Purpose The present invention has the purpose of developing an air circulation arrangement according to the exordium of claim 1 and of the subordinate claim 6 in a simple manner in such a way that for different operating states of the connected equipment, optimum operating conditions are obtained. and particularly noise suppression. Advantage of the present invention The air circulation arrangement according to the present invention solves the proposed purposes with the criteria indicated in the characteristic part of claim 1 and of the subordinate claim 6. The circulation arrangement of air according to the present invention is particularly advantageous in that an adaptation to different load states can be carried out by varying the suction path and the air suction geometry., by way of example, by varying the number of active cylinders of an internal combustion engine, particularly as regards the optimization of the noise emission. The present invention describes a flexible system for sucking different air flow rates, particularly under pulsating air current conditions. By means of the two adjustment devices according to claim 1, it is possible to carry out in a particularly advantageous manner an inversion of the air circulation paths which are between said adjustment devices or trajectories. of sound propagation through at least three circulation channels, by way of example constituted by flexible sleeves. In the case of the inventive embodiment, a throttle valve in each adjustment device can take two reversal positions, with which it can be achieved by deflecting the air current, either through an air circulation path or through an air flow path. long and narrow air circulation path or sound propagation path, short and wide. An air circulation arrangement generally has an air filter with a suction hose on the inlet side. These parts constitute a Helmholtz resonator connected in series - whose resonance frequency follows from the following formula: frßI = 340 / 2p A / 1 * V fres = "Resonance frequency, A = Transverse section of the channel resulting from fl air circulation, 1 = Length of the resulting channel of air circulation, V = - Volume of the air filter After a widening of the cross section due to the opening in parallel of the three air circulation channels, a triplication results • 10 of the resonance frequency and in the case of an - increase of the length when connecting the three air circulation channels in a tripartition of the resonance frequency. In an application case the lower value can be imported approximately by way of example 25Hz and the upper value can import approximately 75Hz. The attenuation of sound takes place accordingly in the case of sounds above the frequency of 35 Hz or 106 Hz. According to one embodiment, the axes of The throttle valve of both adjusting devices can be rigidly coupled together, thereby resulting in a simple arrangement to achieve the conditions described above. For this purpose, the adjustment devices can be arranged directly on a pair or in an overlapping manner, whereby both throttle valve shafts can be easily coupled together, requiring only one positioning motor to be driven. For a more exact adjustment both butterfly valves are elastically pre-stressed. According to another embodiment, a third adjustment position of the throttle valves is also possible, in which only one throttle valve is moved, the throttle valves consequently having different adjustment positions. If only one throttle valve is displaced as an example from the adjustment position with long and narrow flow channels, the actual length of the air flow channel is shortened in terms of attenuation by factor 3, but the area of the cross section. The resonance frequency ~ is consequently increased by the factor 3 and takes the value of 43.3 Hz according to the example described above, this intermediate position can be used accordingly for an intermediate speed of one motor speed. internal combustion.

The embodiment-mechanics of the embodiment described last is carried out by means of a drive cam provided on a throttle valve shaft so that in a certain angular range of rotation of the directly operated throttle valve the other throttle valve is not dragged In the case of a preferred embodiment of the present invention, namely the operation of an internal combustion engine with a variable number of cylinders, the noise emissions in these operating phases are considerably differentiated. The frequency characteristic of the suction pulses is determined not only by the oscillations of the cylinder pulses, but also by the harmonic waves. The frequency characteristic of the 6-cylinder engine can be described substantially by the synergism of the sinusoidal oscillations of the 6th and 12th harmonics, the amplitudes being considerably smaller than the cylinder pulses. In contrast, the cycle of a 3-cylinder engine oscillates almost exclusively as a sinusoidal wave of the third harmonic and the amplitude increases in this case above the value of the individual pulse, which can cause a difference in the level of the emission of noise of 13dB. According to the present invention, noise emissions can be substantially reduced in the case of operation with disconnected cylinders with an adjustment position of the "long-narrow" air flow path. Particularly the very loud snoring sounds caused by the full-load engine, which are easily transmitted to the passenger cabin in the usual vehicle types and transmitted in amplified form by resonance to the ears of the occupants, can be suppressed successfully. From the foregoing, it can be seen that, in order to reduce the noise emission, in addition to the volume of the suction device, the dimensions of the so-called acoustic neck provided in the suction tube for the attenuation effect are decisive. The narrower and longer the tube segment the lower the frequency at which attenuation occurs. With the inventive embodiment according to claims 6 to 12, it is also possible to carry out in a particularly advantageous manner an elongation and narrowing of the suction path to achieve a better attenuation of the low frequency components. one of two inner tubes can cause the diversion of the sucked air.

Other particularly advantageous developments of the present invention are indicated in the dependent claims. Next, exemplary embodiments of the air circulation arrangement according to the present invention will be described in connection with the drawings, in which: Figure 1 illustrates a cross-section through a first embodiment with a tube segment of an air circulation arrangement provided with two inner tubes in initial state. Figure 2 illustrates a cross-section through a tube segment of an aspiration arrangement with two inner tubes in inverted state. Figures 3 and 4 are representations of the oscillatory behavior of a 3-cylinder engine and a 6-cylinder engine. Figure 5 'illustrates the course of the attenuation effect curves of an acoustic neck as a function of frequency with different numbers of cylinders. Figure 6 illustrates another preferred embodiment in a representation in principle of the air circulation arrangement with three circulation channels capable of being inverted. Figure 7 illustrates in detail the adjustment devices according to Figure 6 c-on mobile butterfly valves arranged in the circulation channels. DESCRIPTION OF THE EXEMPLARY EMBODIMENTS FIG. 1 shows a first exemplary embodiment with a tube segment 1 of a suction arrangement for an internal combustion engine not illustrated here, through which a flow of air flows. air according to arrow 2, in particular arrows 2.0, 2.1 and 2.2. A first inner tube 3 rigidly connected to said tube segment 1 is concentrically arranged in the tube segment 1. Between said first inner tube 3 and the inner sleeve of the tube segment 1, a second inner tube 4 movable in the direction is submerged. axial The second inner tube 4 can be displaced axially to such an extent that it rests in a sealed manner against a stop plate 5. Said stop plate in the present case also serves as a holding means for the first inner tube 3. The first inner tube 3 has at its lower end in the stop plate 5 a plurality of ports 6, the suction air circulating through said ports towards the interior of the first inner tube 3 when the second inner tube 4 according to figure 1 does not it is completely displaced inwards. At the upper end of the second displaceable inner tube 4 a plurality of ports 7 and a sealing disc 8 are provided, whose functions will be described below in connection with Figure 2. The aspirated air flows according to Figure 1 in a parallel direction (arrow 2.0, 2.1 and 2.2) through interstitial chambers 9 and 10 as well as through the inner tube 3. In the case of this described embodiment, the movable inner tube 4 takes the position indicated in figure 1 prior to a reversal of operation with 6 cylinders to operation with 3 cylinders, allowing said position a "parallel circulation of air through the three tubular chambers.The path of air circulation imports L and the circulation cross section has the value 3 * A, where A represents the cross-sectional area of one of the tubular chambers 3. In FIG. 2, the second inner tube 4 is displaced downwards in a The same is supported with its lower end in a sealed manner against the stop plate 5. This forces the circular sucked air through the first interstitial chamber 9 (arrow 2.3), the air being diverted by the shut-off disk 8. towards the ports 7, the air circulating back into the second interstitial chamber 10 against the direction of aspiration (arrow 2.4). At the end of the second interstitial chamber 10 the air passes through ports ~ 6 provided in the first inner tube and flows according to arrow 2.5. According to arrow 2 an air circulation path has materialized accordingly, which measures three times from inside to outside the length of the tube segment 1. After the reversal of operation with 6 cylinders to operation with 3 cylinders, the second displaceable inner tube 4 has inventively taken the left stop position according to the figure 2. The air circulation path now imports 3 * L, and the circulation cross section imports "A". The reduction in a third of the cross section and the triplication of the air circulation path can be considered as neutral in terms of aerodynamic resistance since with the inversion towards the air circulation path according to figure A a state is simultaneously adjusted of operation of the engine, in which due to the lower power requirement a correspondingly lower air flow is drawn. Based on figures 3 to 5 the attenuation behavior of the air suction arrangement according to the exemplary embodiment described above will be described. 3 shows the time course of the pulsing sequence of the suction pulses in the case of operation with 3 cylinders and in FIG. 4 in the case of operation with 6 cylinders. The cycle of the 6-cylinder engine according to Figure 4 illustrates the concurrence of the sinusoidal oscillations of the 6th and 12th harmonic of a 720 ° work cycle, being able to recognize that the amplitudes of the resulting oscillation are substantially smaller than that of a individual pulse. In contrast to the previously described, the 3-cylinder cycle according to Figure 3 oscillates almost exclusively with sinusoidal waves of the third harmonic, increasing the amplitude above the value of the individual impulse. In the case of a number of revolutions of the engine of for example 3000 Rpm results in the case of operation with 6 cylinders a disturbing frequency of 15OHz, while it imports 75Hz in the case of operation with 3 cylinders. By way of calculation, a ratio between amplitudes of 1: 4.5 is obtained in the case of a 6-cylinder operating reversal with 3-cylinder operation, which is important for a noise level difference of 13 dB.

Figure 5 shows the attenuation curves as a function of frequency for both operating states. By means of curve 30, the attenuation path has been indicated in the case of operation with 6 cylinders and with curve 31 the attenuation path has been indicated in the case of operation with 3 cylinders. In order to optimize the attenuation behavior, it should be noted that in addition to the magnitude of the volume, the dimensions of the acoustic neck are decisive for the attenuation effect. The narrower and longer a tube segment the lower the frequency at which attenuation occurs. The aim of the packs in terms of the acoustic field must be to arrive at the resonance frequency fres below the excitation frequency since the desired attenuation only takes place from the value v2 * fres. This results in the consequence that during the change of operation with 6 cylinders to operation with 3 cylinders the resonance frequency of the attenuator tube segment 1 should be reduced by the factor of 3.77 if an increase in the acoustic level is desired. The aforementioned demands in turn modifications in the dimensions of the attenuation neck or of the length and cross-sectional area with a total effective ratio of 14.22. As illustrated in figure 5, in the case of this supposed case of materialization of the operation with 6 cylinders the resonance frequency would import 66Hz and the attenuation would import with 150Hz 12dB (curve 20). After the reversal to 3-cylinder operation the excitation frequency would be 75Hz and the attenuation should import 25dB due to the more intense excitation at 13dB. With the air suction arrangement according to this embodiment, it is achieved that the acoustic levels evaluated can be maintained since the 75Hz tone is evaluated at 9.5dB (A) weaker than the 150Hz tone. In this context, a tuning to the resonance frequency of 22Hz is sufficient, which represents a frequency reduced by the factor 3. The tone of 75Hz presented in this case is attenuated by 20dB (curve 31). The inventive embodiment according to FIGS. 1 and 2 consequently allows a triplication of the length of the attenuator neck and a reduction by three of the area of its cross-section, which leads to the desired success. In figure 6 there is illustrated another preferred embodiment 11 of the air circulation arrangement according to the present invention, through which the air circulates as indicated by the arrows 12. Between two adjustment devices 13 and 14 three air circulation channels 15, 16 and 17 have been arranged, the direction of circulation in the air circulation channels 15, 16 and 17 can be inverted by butterfly valves 18 and 19 (not visible in this figure). The air circulation channels 15, 16 and 17 are preferably made of flexible material so that said air circulation arrangement 11 can also be arranged in a location of a piece of equipment (for example in the vehicle's engine compartment) Figure 7 shows in detail the adjustment devices 13 and 14 with their throttle valves 18 and 19. The throttle valves 18 and 19 can be rotated on the throttle axes 20 and 20. 21, said wing axes 20 and 21 being able to be kinematically coupled -among each other, as can be seen in principle from FIG. 6. In case the throttle valve 18 is positioned in the position indicated in FIG. 6 in the adjusting device 14. , the air stream is conducted according to the arrows 12 through a lower ong 22 towards the circulation channel 15 (compare figure 6) and subsequently towards an ong 23 of the device Adjustment 13. By positioning the throttle valve 19 in the adjusting device 13, the air is further conducted through an ong 24 in the circulation channel 16, thereby reaching the air with an ong 25 of the adjusting device 14. Also in this case the return air is conducted by means of the positioning of the butterfly valve 18 through an ong 26 in the circulation channel 17, passing the air through an ong 27 to the adjustment device 13, through the which can flow outwards.

In the case of the air flow path described above, it is therefore a series connection of the three circulation channels 15, 16 and 17, resulting in a long, narrow and effectively attenuating path. " another position of the butterfly valves 18 and 19, ie in the respective open state illustrated with dotted lines, all the openings of the adjustment elements 13 and 14 are open so that the air can flow in parallel "through all the circulation channels 15, 16 and 17. In this way a short and wide air circulation path is obtained through the three "circulation channels 15, 16 and 17. In the present case the axes 20 and 21 of the butterfly valves 18 and 19 are mechanically coupled to each other, being generally adjusted in mutually parallel manner and driven by the same servomotor, taking the same position in the respective adjustment device 13 or 14. By means of non-illustrated dragging cams arranged on one of the butterfly shafts 20 or 21, directly actuated or indirectly driven, the indirectly driven butterfly valve 18 or 19 can remain within a certain angular range of rotation in the initial position, thus resulting in another adjustment position. In said last adjustment position the air circulates only through one of the three circulation channels 15, 16 or 17, obtaining with respect to the adjustment position initially described a shortening in the factor 3 of the length of the circulation path of air with the same cross section. When a subsequent rotation of the driven shaft takes place, the adjustment position corresponding to parallel currents results from the effect of the drive cam.

Claims (14)

1. CLAIMS 1. - Aspiration arrangement of "air for a post-connected equipment, of the type in which it has been arranged in the area of" the air suction path adjustment devices to vary the air circulation geometry for the air circulating, CHARACTERIZED because the total cross section of the air circulation path is subdivided into individual circulation channels and the air circulation paths in the different circulation channels are adjustable by means of the adjustment devices to influence the effective length and the effective cross section of the entire air suction arrangement. 2. - air aspiration arrangement according to claim 1, characterized in that it has at least three air circulation channels, which are connected at their ends in each case to an interior opening of the adjustment devices and because in each of said adjustment devices are provided with butterfly valves, which in a first control position guide the air flow from the input in the first adjustment device through the air circulation channels successively in alternating directions towards the exit in the second adjustment device and the air flow being conducted in a second control position from the "input in the first adjustment device in a parallel fashion through all the flow channels to the outlet in the second adjustment device. - Air aspiration arrangement according to claim 2, CHARACTERIZED because the butterfly valves (they are mounted in c rotate the case rotatably on an axis, circulating the air with the butterfly valves (in a first control position in parallel through the three air circulation channels and being closed by the butterfly valves (18,19) in a second position In each case, two openings of the adjusting devices (so that they are closed towards the inlet or towards the outlet), however, a current of air between these openings on the side directed to the circulation channels is possible. __ 4. - Air aspiration arrangement according to claim 3, CHARACTERIZED because the axes (of both butterfly valves (are rigidly coupled to each other and are driven in common by means of a positioning motor. 5. - Air aspiration arrangement according to claim 3, CHARACTERIZED because the axes of both throttle valves (are actuated jointly by means of a positioning motor and are mutually coupled so that the directly driven shaft or the indirectly driven shaft presents a cam 6.- Air suction arrangement as a suction device for an internal combustion engine - - in which the direct drive shaft causes an adjustment of the throttle valve. provided in the area of the air suction path means for varying the air circulation geometry for the sucked air, characterized in that at least one tube segment with at least two inner tubes is provided in the air suction path. The diameters of said tubes are sized in such a way that the first inner tube and the second inner tube can to be displaced one inside the other in the tube segment _because - means have been provided to vary the air suction path in the tube segment, by means of which the air circulates either in a parallel direction through the tube segment and the inner tubes or through which the air circulates through interstitial chambers formed by the tube segment and the inner tubes, which are connected successively in changing directions, as well as through the first inner tube that is in the most inside. 7. Air aspiration arrangement according to claim 6, CHARACTERIZED in that the first inner tube is firmly anchored in the tube segment, having provided in the first inner tube at least one port for air intake and because the second inner tube provided with ports and sealing elements is movable on the first tube inside the tube segment so that in the initial position the air circulates in parallel through all the interstitial chambers and through the first inner tube and in the inverted position there is a serial connection of the following suction paths: - air circulates in the suction direction through a first interstitial chamber defined between the tube segment and the second inner tube; at the end of this first interstitial chamber the air circulates in the opposite direction through the interstitial chamber defined between the first inner tube "and the second inner tube, and - at the end of the second interstitial chamber the air passes to the first inner tube and circulates in the direction of suction outside the tube segment 8. - air aspiration arrangement according to claim 7, characterized in that - in the inverted position is defined by means of the at least one port provided in the first inner tube a via link from the interstitial chamber to the outlet channel by: on top of the end of the second inner tube, which is on the suction side, because - the second inner tube has at least one port to communicate the first interstitial chamber with the second interstitial chamber, and because at the other end of the second movable inner tube a sealing ring has been provided to seal out the ambient interstitial cameras. 9. Air aspiration arrangement according to claim 7 or 8, characterized in that it comprises a stop plate, in whose area openings are provided for air in the suction way and which also constitutes a stop for said end of the second inner tube movable in the inverted position and in which the first inner tube is firmly attached. 10. Air aspiration arrangement according to at least one of claims 7 to 9, characterized in that the second inner tube is displaceable on support elements that are provided externally on the first stationary inner tube. 11. Suction arrangement according to at least one of claims 7 to 10, characterized in that the second inner tube is displaceable on support elements provided internally in the tube segment. 12. - air aspiration arrangement according to at least one of claims 7 to 11, characterized in that the control pulses necessary for the displacement of the second inner tube are generated by a hydraulic system of a motor vehicle based on the active number of cylinders of the internal combustion engine. 13. - air aspiration arrangement according to at least one of claims 1 to 5, characterized in that it is a suction arrangement for an internal combustion engine of a motor vehicle. 14.- Air aspiration arrangement according to claim 13, characterized in that the automotive vehicle has a device for disconnecting a part of the cylinders of the internal combustion engine. SUMMARY The present invention relates to an air suction arrangement for a post-connected equipment, of the type in which adjustment devices have been arranged in the area of the air circulation path to vary the circulation geometry for the air circulating, which is characterized in that the total cross section of the air circulation path is subdivided into individual air circulation channels and the air circulation paths in the different circulation channels are able to control the air flow through the adjustment devices. about the effective length and the effective cross section of the air suction arrangement ep.