RU2134356C1 - Multicylinder internal combustion engine - Google Patents

Abstract

FIELD: mechanical engineering; multicylinder internal combustion engines with fuel injection into cylinders. SUBSTANCE: internal combustion engine has cylinder head with intake holes in which intake valves are fitted, intake branch pipes with means for fuel delivery laid directly from intake holes and opening in gas collecting receiver connected to air cleaning system. Side wall of receiver has connecting holes for said branch pipes, and one of end face walls has through neck by means of which receiver space is connected to air cleaning system. Receiver accommodates also noise-and-gas fluctuations damper made of porous noise-absorbing material permeable to gas. Novelty is that damper is made in form of convex diaphragm placed in receiver neck overlapping its through passage. Diaphragm has streamlined shape arching towards receiver space. Diaphragm can be provided with through perforation holes, and conductivity (porosity) of diaphragm structure can differentially increase from its periphery to center. EFFECT: enlarged operating capabilities. 4 cl, 12 dwg

Description

 The invention relates to engine building, in particular, to multi-cylinder internal combustion engines with fuel injection into cylinders.

 In the intake systems of carburetor internal combustion engines (hereinafter ICE), the presence of diffuser elements provides a weakening of the resonant properties of the system as a whole, because due to the significant active resistances of these elements, the system becomes less “sound” (i.e., the resonant frequencies are partially damped). This, to a certain extent, is a positive factor, because on the one hand, cylinder filling losses (loss of effective power, deterioration in engine efficiency) are compensated for due to a decrease in the resonant amplitudes of the pulsations of the volumetric air flow (and the increase in the hydraulic resistance of the system is known to be proportional to the square of the amplitude of the pulsations of the gas flow). On the other hand, the suppression of resonant pulsations of gas in the intake system of the internal combustion engine is favorable from the point of view of sound (noise) radiation into the environment produced by both the open ends of the air intake pipes of the air cleaner (aerodynamic noise) and the vibrating walls of the intake system elements (structural, cabinet noise).

 Thus, the elimination of the carburetor as a conservative device that does not provide high environmental characteristics of the internal combustion engine and the vehicle as a whole ("coarse" fuel dosage, evaporation of fuel vapor from the carburetor, etc.) and the use of electronic fuel injection system necessitates the use of devices in the internal combustion engine design additional attenuation or elimination of the above adverse events. For this purpose, the use of a wide variety of devices is currently known.

 So, for example, the Japanese company "Yamaha Motor" in the application N 61-244824, F 02 B 27/00, publ. 10/31/86, to reduce ripple and noise, suggests using two receivers, parallel and in series, connected to the pipeline route.

 The Japanese company "Honda Motor" in the application N 63-219866, F 02 M 35/10, publ. 09/13/88, suggests using two separate air lines connecting the air purifier and the receiver with two controlled throttles to reduce intake noise when suction is used to close the auxiliary channel at low revs and open both connecting pipelines at high revs. The same company in the application N 61-190159, F 02 M 35/12, publ. 14.01.87, in order to ensure sound attenuation in a wide range of frequencies, it proposes to connect two sound attenuation devices to the inlet pipe - a 1/4 dead-end wave resonator and a resonant chamber.

 EPO N 0278117, F 02 B 27/00, publ. 08/17/88, to use the effects of increasing the filling of the cylinders, by suppressing resonant pulsations of the gas by adding them in antiphase, it is proposed to use mutually agreed additional resonant tubes and an additional receiver.

 The Austrian company "AVL" in the application of Germany N 3820607, F 01 B 25/00, publ. 12/29/88, to expand the frequency range of the effective operation of the additional resonator, offers to carry out its design of variable volume depending on the speed of rotation of the crankshaft.

 The Japanese company "Nippon Radzieta" in the application of Japan N 62-48047, F 01 N 1/02, publ. 12.10.87, proposes, in order to increase the effect of damping noise, instead of using large-sized complex designs of silencers, use an anti-resonance inlet pipe, including a controlled noise or vibration source, an electromagnetic valve, receiving acoustic sensors, and a control processor.

 Japanese company "Hitachi seisakuse" in the application of Japan N 2-4840, F 16 L 55/04, publ. 01/30/90, in order to reduce fluctuations in the piping system, it proposes that the pipeline branch into at least two channels, at different distances from the branch point to place expansion chambers that reflect direct incident waves back to the pulsation source (engine cylinder), and the distance between the walls of the chambers is selected a certain way.

 The English branch of the Ford Motor company in the application of Great Britain N 2203488, F 02 B 29/00, publ. 10.19.88, to suppress gas pulsations and noise in the intake manifold, provides for the installation of an “anti-sound” device in the form of a special loudspeaker or a special reservoir with an electrovalve.

 Japanese company Nissan Jidosia in Japanese application N 51-23656, F 02 B 37/00, publ. 05/08/89, to reduce the intake noise of the internal combustion engine and increase its power, due to a decrease in the reverse current of the charge air, it is proposed to use a special muffler design in the form of an expansion chamber with internal tubes of a certain ratio of diameters and a certain distance of the pipe sections between each other.

 The Canadian branch of Siemens-Bendix in US Pat. No. 4,934,343, F 02 M 35/00, for damping gas flow noise, without significantly affecting the hydraulic resistance of the inlet tract, provides for the use of two diffuser sections in a bifurcated section of the gas pipeline that provide phase shift and compensation of pulsation amplitudes when they are added in the connection zone.

 The French company Peugeot in French patent N 2536792, publ. 06/22/84, the use of a throttling plate or diffuser insert narrowing the inlet section of the inlet pipe to reduce the intake noise of ICE with direct fuel injection is claimed. The throttle washer or diffuser insert to ensure the required efficiency is located in the antinode wave of the vibrational velocity of the gas stream at some given speed mode of operation of the internal combustion engine. An obvious disadvantage of the device is the increase in hydraulic resistance of the intake system due to narrowing of the bore and, as a consequence, the deterioration of power, economic and environmental (toxic) parameters of ICE. Also, the location of the throttle washer or diffuser insert in one specific place of the inlet path allows you to effectively act on only one resonant frequency and multiple odd harmonics, i.e. there is a limited impact on individual high-speed engine operation modes.

 The American branch of the company Siemens Bendix in US patent N 4907547, F 02 M 35/10, publ. 03/13/90, to suppress noise and pulsations in the intake system of the engine, it is proposed to use a special wave reflector located across the inlet pipe of one of the cylinders and a pair of cylinders on a rotating roller, which, when turned, provides selective opening of one of the neighboring inlet pipes of the engine cylinder.

 The Japanese company Mazda Motor in ЕВП N 0376299, F 02 M 35/12, publ. 07/04/90, to suppress gas pulsations and noise in the intake system of the internal combustion engine, a special device is provided for suppressing each of the resonant harmonics of pulsations that are multiples of λ (0.5 + n) the lengths of the resonant waves of pulsations, where n is an integer equal to zero or more than zero .

 The German company Volkswagen in the application of Germany N 3742322, F 02 M 35/10, publ. 07.07.88, it is planned to dampen the fluctuations in the flow of intake air in the internal combustion engine due to the inclusion of an additional “soothing” receiver with elastic walls in the intake tract, in which, due to the elastic deformation of the receiver walls, due to the pulsating effect of the gas flow, pulsation energy will be converted into thermal energy in an elastic wall material with high internal friction of the material (rubber). The obvious disadvantages of such a system include the high cost of the device, the instability of the operational characteristics of the elastic wall, low durability, the risk of untreated air entering the ICE cylinders when the elastic wall is damaged, significant sound emission from the “pulsating” elastic wall, etc.

 Analyzing and summarizing the results of the above patent review, it should be concluded that all of the above devices to improve acoustic performance and reduce gas-dynamic pulsations in the intake systems of ICEs and, accordingly, improve their power, economic and environmental performance are associated with the use of additional expansion or resonance chambers connected in parallel and sequentially to the intake tract using electronic systems for the formation of artificial anti communication signals to compensate actual signals ripple and noise, using additional receivers, additional controlled ducts and chambers with variable volume, branched gazovodov fazoupravlyaemymi with diffuser sections.

 Known internal combustion engine company "Mazda Motor", described in the application EPO N 0379926, F 02 M 35/12, publ. 08/01/90, containing a cylinder head, with inlet openings in which inlet valves are installed, inlet nozzles extending directly from the inlet openings and exiting into the gas collection receiver, the side wall of which is provided with connecting holes for the said nozzles, and mounted along the receiver cavity, mounted on its end wall is a fitting. Three resonant silencers are connected to the engine intake system (between the throttle and the air cleaner), which are directly connected to the receiver volume, the pipe between the receiver and the air cleaner chamber and the volume of the air cleaner chamber, respectively.

 The effectiveness of the use of each individual soundproofing element, effective only in a narrow frequency (speed) range, necessitates the joint use of three of these silencers simultaneously.

 But, given the wide speed mode of the engine, the presence of a large number of natural frequencies of oscillations of individual elements of the gas ducts, resonating when they coincide with the frequencies (or their multiple harmonics) of forced oscillations (gas pulsations during the opening and closing of the intake valves and at the time of phase overlap in the processes gas inlet and outlet in ICE), the use of even several highly tuned parallel-connected resonators cannot provide the required efficiency over the entire operating range s and loads, and it is only able to suppress or somewhat compensate for the most pronounced "acoustic defects" of the system in separate (separate) modes, which is confirmed by the illustrations of experimental estimates given in the application.

 The disadvantages of such an intake system are also obvious from the point of view of material consumption, limited layout options in the cramped space of the engine compartment of the car, as well as the adverse effect on the change in the coefficient of excess air during the intake in unsteady modes of intense acceleration of the car engine.

 As a prototype adopted an internal combustion engine, patent of the Russian Federation N 2078220, class. F 02 B 29/02, publ. 04/27/97, bull. N 12, comprising a cylinder head with inlet openings in which inlet valves are installed, equipped with fuel supply means (for example, nozzles) inlet pipes extending directly from the inlet openings and exiting into a gas collection receiver connected to the air cleaning system, the side wall of which is provided with connecting openings for the aforementioned nozzles, and installed in the cavity of the receiver, mounted on its side wall fitting, which is placed inside the receiver, its output is connected to the air system cleaning the engine, while the nozzle is made of a gas-permeable, sound-absorbing material, and its length is not less than the distance from the attachment point of the nozzle on the receiver to the most distant cut of the connecting hole, extreme with respect to the attachment point of the inlet nozzle.

 The intake engine intake system has a high noise suppression and gas pulsation suppression in a wide frequency and speed ranges of the engine and does not complicate the overall layout of the vehicle components in its rather cluttered space of the engine compartment.

 As applied to ICE intake systems, the receivers of which have an approximately regular cylindrical body shape, the described technical solution is the most optimal damping gas pulsation and noise-reducing design. However, in the practice of designing and manufacturing ICE intake systems, depending on the specific location of the engine, its components, systems and elements in the engine compartment, very often the receiver body acquires a very different shape, sometimes not only without a central axis of symmetry, in particular, even close not reminiscent of the right cylindrical. In such cases, to place a fitting in the receiver cavity, the length of which would overlap the connecting holes of the inlet pipes of all engine cylinders, becomes impossible or extremely difficult. Thus, the prototype narrowed the field of practical implementation of the object of the invention, since it is feasible only in intake systems, the receiver of which has a fairly regular geometric shape with a central axis of symmetry.

 The objective of the invention is the expansion of the field of practical implementation while ensuring high efficiency of noise suppression and suppression of gas pulsations in the path of the engine intake system in a wide frequency and speed ranges of its operation, as well as reducing material consumption, simplifying the design and manufacturing and assembly technology, cheapening the design, further simplifying the layout solutions for placing the units in the engine compartment, due to the possibility of choosing almost any form of the receiver body.

 The essence of the invention lies in the fact that in the known internal combustion engine containing a cylinder head with inlet openings, in which there are inlet valves equipped with fuel supply means, inlet pipes extending directly from the inlet openings and leaving the gas collection receiver connected to the air-cleaning system, the side wall of which equipped with connecting holes for the named pipes, and the end wall is equipped with a hole through which the cavity of the receiver is connected to the air cleaning system, and wherein the noise damping element secured and gas pulsations is made of gas-permeable sound-absorbing material called the element is a diaphragm overlying orifice receiver neck, i.e. in the zone of a sharp jump in the wave resistance of the gas duct (intake path). The diaphragm may have a regular convex shape towards the receiver cavity, for example, the shape of a cone, hemisphere, trapezoid. At the same time, the diaphragm may be provided with one or more through holes of perforation. The permeability (conductivity) of the structure of the diaphragm can differentially increase from the walls of the hole (the fixing point of the diaphragm) towards its center (the geometric center of the hole in which the diaphragm is mounted).

 Due to the fact that such a device is arranged in a fairly close zone to the inlet valve and cylinder - the main source of pulsations and noise of the inlet system, and this zone is characterized by the maximum concentration of acoustic energy, in contrast to the impact on the design parameters of the air purifier, far removed from this zone , the efficiency of suppressing noise and gas pulsations at the inlet can be achieved to a much higher degree with minimal structural impact on the ICE intake system.

 In fact, the plot of the sound pressure distribution on the first eigenmode of the intake tract, which is most responsible for the resonance phenomena of the tract, is characterized by a cosine wave with a maximum value in the valve area and a minimum value in the area of the air cleaner chamber. Accordingly, placing the noise and ripple suppression devices closer to the source of noise and ripple, i.e. to the zone of maximum concentrations of wave energy, it is possible to increase the efficiency of their use.

 At the same time, the aforementioned gas-permeable sound-absorbing membrane is a compact and uncomplicated fabrication design, which has a low material consumption in comparison with the prototype. Moreover, the membrane design is practically independent of the geometric features of the receiver, which makes it possible to use it in a variety of intake systems equipped with receivers.

 As in the prototype, the design of the receiver with a diaphragm located inside it, made of gas-permeable sound-absorbing material, can be considered as a silencer with active friction in series.

The invention is illustrated in the drawings, where:
- in FIG. 1 shows a fragment of the inventive engine (gas supply path to the engine cylinders),
- in FIG. 2 shows the connection of the neck of the receiver with an air purification system,
- in FIG. 3 shows a fragment of the gas supply path from the neck of the receiver in which the diaphragm is installed (one of the possible design options) to the engine inlet valve,
- in FIG. Figure 4 shows the connection of the neck of the receiver with the intake pipe of the engine, in which (the connection) has a diaphragm, the conductivity of which increases from the walls of the receiver to the center of the cross section of its neck (controlling the conductivity of the membrane also involves changing its thickness, using different sizes of through cells and t .P.)
- in FIG. 5 shows a similar view to FIG. 3 connection, with a diaphragm perforated by one central hole, convex into the cavity of the receiver,
- in FIG. 6 ... 11 show some preferred options for the possible design of the diaphragms,
- in FIG. 12 shows the results of experimental evaluations of the acoustic effectiveness of the claimed device.

 The internal combustion engine comprises a cylinder head 1 with inlet openings 2 in which inlet valves (not shown) are provided, equipped with fuel supply means (not shown) inlet pipes 4, extending directly from inlet openings 2 and exiting into the gas collection receiver 6 connected to the air purification system 5 , the side wall of which is provided with connecting holes 7 for the named pipes 4, and a diaphragm 9 mounted in its receiver 6, mounted on its neck 8. The diaphragm 9 is made of gas permeable and a sound absorbing material covers the mouth of the passage section 8 of the receiver 6.

 A symmetrical, streamlined geometric shape of the diaphragm convex towards the volume of the receiver 6 is preferred, as shown in FIG. 5 ... 10, for example in the form of a hollow cone, a truncated cone, a hemisphere, moreover, the diaphragm 9 can be solid (Fig. 6-8), or perforated with one or more through holes (Fig. 9-11). In addition, FIG. 3, the porosity (conductivity) of the diaphragm structure can smoothly increase from its outer edges to the center of the diaphragm.

 Additionally, the figures show: the end wall 10, in which the neck 8 of the receiver 6 is made, a pipe with a throttle valve 11, an inlet pipe 12 and an air intake pipe 13 of the air cleaner 14.

 Opening the intake valve causes a pressure differential in the cylinder tank, which is formed by the surfaces of the piston bottom and the combustion chamber (behind the valve) and in the environment. In this case, the vibrational pulse in the form of elastic waves propagates with the speed of sound in the air filling the inlet tract, as a result of which the air volumes of the inlet pipes 4 are closed with the intake valves closed (dead-end waveguides) and the sound fields and gas-dynamic gas pulsations interact and are connected in the pipes 4, which complicates the uncoupling (separating) action of the receiver 6, the formation of a sound field in the space of the receiver 6, the reflection of sound waves from the walls of the receiver 6 towards to the quick valves of the nozzles 4 and the “displacement” of sound energy into the inlet pipe 12, as into a transmitting waveguide with a certain acoustic conductivity (a certain acoustic resistance) and makes it necessary to abruptly overcome the growth of acoustic resistance when elastic waves pass through the diaphragm 9 through its porous structure, as a result what is the dissipation of vibrational (sound) energy in the porous breathable sound-absorbing material of the diaphragm 9 due to friction of the oscillating parts c gas and energy losses due to microdynamic deformation of the material and the conversion of this vibrational energy into heat. Also, in addition to dissipating the vibrational energy of the gas in the porous material of the diaphragm 9, the sound insulation of the system grows in the direction of the inlet section of the air intake pipe 13, due to the additional reflection of the sound waves back towards the inlet valves.

 Due to the fact that the gas-permeable convex diaphragm 9 does not narrow the bore of the neck 8 of the receiver 6 (due to the developed surface of the diaphragm in the form of convex surfaces), as a result of the damping of the gas pulsations by the diaphragm 9, the hydraulic resistance of the intake system as a whole decreases at a given gas flow rate, sucked into the cylinders and passing through the receiver 6 (the hydraulic resistance of the tract during transportation of the pulsating gas flow is determined by the square of the amplitude values of the pulsations).

 The physical and mathematical model of the dynamic state of the object described above is as follows.

Each of the 4 cylinders of the four-stroke internal combustion engine during its operation generates a series of suction pulses. This sequence of pulses creates oscillations (pulsations) of the gas volumetric flow rate with a fundamental frequency:
f ₁ = n / 2 • 60, Hz
and multiple frequencies:
f _m = m • f ₁ , Hz
where m = 1, 2, 3;
n is the number of revolutions per min.

и по фазе: для 4-цилиндрового двигателя происходит сдвиг по фазе для первой гармоники, равный

где k - порядок следования импульсов по цилиндрам в соответствии с порядком работы цилиндров. Для первого цилиндра k=1, для второго k=4, для третьего k=2, для четвертого k=3.Fluctuations in gas flow in different cylinders are shifted in time:

and in phase: for a 4-cylinder engine there is a phase shift for the first harmonic equal to

where k is the order of the pulses along the cylinders in accordance with the order of the cylinders. For the first cylinder k = 1, for the second k = 4, for the third k = 2, for the fourth k = 3.

где C - скорость звука, м/с
p = 1, 2, 3,...π = 3.14 rad
For the nth harmonic, the time shift is the same, but in phase;
φ _m = m • φ ₁ , rad
An engine with a receiver in the intake system helps ensure separate cylinder pressurization due to a significant break in the dynamic connections between the nozzles and the receiver volume. On the other hand, the mutual independence of the wave phenomena in the pipes connecting the receiver to the cylinders leads to a sharper development of gas oscillations in each pipe separately. These resonant oscillations appear at the natural frequencies of the nozzles

where C is the speed of sound, m / s
p = 1, 2, 3, ...

L _{n is the} length of the pipe, m

At the lowest resonant frequency (f ⁽¹⁾ ), others associated with the nozzles of the mass of gas (directly in the receiver and adjacent elements) are partially involved in the system that forms the resonant circuit.

Due to the asymmetry of the acoustic loads generated by the receiver design, the acoustic loads on the nozzles of individual cylinders are different and this leads to a slight mismatch of the resonant frequencies (f ⁽¹⁾ ) of the individual nozzles. Therefore, the resonant oscillations of the gas arising in one of them (at its resonant frequency) are not suppressed by the vibrations coming to the receiver from other nozzles, even if the initial pulses from the cylinders are compensated (go in antiphase).

The second unfavorable acoustic phenomenon is associated with the excitation of the first asymmetric resonant form of gas oscillations in the receiver. As a rule, its frequency is close (or a multiple) to one of the natural frequencies of gas oscillations in the pipe, which leads to a resonant amplification of sound radiation from the system, especially at frequencies of odd harmonics of the fundamental frequency of the suction process (f ₁ ). This implies the transfer of amplified sound radiation from the receiver to the intake system towards the free open end of the air intake pipe of the air cleaner. On the path of this transmission chain, this sound radiation will transform (vary in spectral composition, partially amplify or attenuate in amplitude) throughout the transmission path (intake pipe 12, air cleaner 14, air intake pipe 13, engine compartment and the environment).

 Given the important role of the receiver in the formation of acoustic loads acting directly on the inlet pipes, and on their interaction with each other, on the one hand, and on the transfer of acoustic energy through a free transmission circuit (through the intake system) into the environment, on the other hand, It is logical to pose the problem of introducing into the receiver an effective sound-blocking element for the free transfer of acoustic energy.

 Moreover, as was already noted above, the locally proposed impact zone (receiver cavity) is a zone of high concentration of sound energy, as well as the fact that under resonant regimes the gas in the system oscillates like gas in strongly interconnected volumes with disturbed (insufficient) separation of air volumes (i.e. the main function of the receiver is violated - the separation of the cylinders with obtaining their improved filling due to dynamic boost). In this case, such a proposed element for improving the basic functions is the diaphragm 9.

 Since the convex diaphragm 9 is made of a gas-permeable material (for example, metal rubber, porous mesh material or other similar materials), the structure is a homogeneous structure (although for the strength of the structure the diaphragm may contain rigid skeletal reinforcement), it does not narrow the passage section of the neck of the receiver 8, completely blocking it, damping low-frequency resonant pulsations in the receiver space, as a result of this pulsation damping, the hydraulic otivleny intake system at a predetermined flow rate of gas sucked into the cylinder and passing through the receiver. Reducing the hydraulic resistance of the intake tract in some cases can improve the filling of the cylinders with a fresh charge, and, accordingly, improve the power, economic and toxic characteristics of the engine.

 The geometric shape of the diaphragm, the thickness of its walls, the porosity of the structure of the diaphragm, are chosen experimentally, depending on the specific design of the engine and its intake tract. The convex shape and perforation of the diaphragm through holes (if necessary) can additionally avoid the growth of hydraulic resistance in the intake path.

 Below are the results of the performed experiments, which make it possible to judge the rather high efficiency of the proposed technical solution.

 Presented on the charts of Appendix No. 1, the results of experimental evaluations of the acoustic efficiency of the claimed device on a 4-cylinder 16-valve with electronic fuel injection VAZ engine with a working volume of 1.5 l show that the total noise levels of the intake emitted by a free cut of the air intake pipe of the air purifier are significantly reduced in the entire controlled speed range of the engine (at certain speed modes, a decrease in the overall levels reaches 8 dBA), which is mainly due mainly absorption of sound energy in the mid-frequency range 63 ... 2000 Hz.

Claims (4)

 1. A multi-cylinder internal combustion engine containing a cylinder head with inlet openings, in which inlet valves are installed, equipped with fuel supply means inlet branch pipes that extend directly from the inlet ports and exit into a gas collection receiver connected to the air cleaning system, the side wall of which is provided with connecting holes for the said branch pipes , and one of the end walls is equipped with a passage through which the cavity of the receiver is connected to the air system cleaning, and a silencing and gas pulsation silencing element located in the receiver, made of porous gas-permeable sound-absorbing material, characterized in that the noise and gas pulsating silencing element is made in the form of a convex diaphragm located in the neck of the receiver and overlapping its passage section.  2. The engine according to claim 1, characterized in that the diaphragm has the correct shape of the body of revolution, convex towards the cavity of the receiver.  3. The engine according to claims 1 and 2, characterized in that at least one through hole of the perforation is made in the diaphragm.  4. The engine according to claims 1 to 3, characterized in that the conductivity of the structure of the diaphragm differentially increases from its periphery of the edges towards the geometric center.

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