RU194107U1 - THERMAL-ACOUSTIC SILENCER OF THE VEHICLE ENGINE - Google Patents

Abstract

The utility model relates to the field of damping the noise of exhaust gases in an internal combustion engine, namely to thermoacoustic silencers of an automobile engine. The thermoacoustic silencer of an automobile engine is located in the exhaust system along the direction of their movement after the catalytic converter. The acoustic silencer includes a heat exchanger, expansion chambers, intake and exhaust manifolds. The heat exchanger is made in the form of three heat exchange sections. Each of the heat exchange sections contains internally located heat exchange tubes filled with porous metal, and externally equipped with installed inlet and outlet pipes for supplying coolant to the annulus and for draining the coolant from the annulus passing through the flow turbulators. Inside the expansion chambers, elements of sound-absorbing material and perforated walls are installed for supplying and discharging exhaust gases from the heat exchange sections and expansion chambers. The intake and exhaust manifolds contain an element of sound-absorbing material and a permeable perforated wall that repeat the configuration of the inner surface of the collectors. The technical result consists in increasing the efficiency of the thermoacoustic silencer of an automobile engine, which has smaller dimensions and a reduced weight of the structure. 2 s.p. f-ly, 3 ill.

Description

The utility model relates to mechanical engineering, in particular to engine building, and can be used to dampen the noise of the release of gases in an internal combustion engine.

At present, reactive and absorption silencers, as well as combined reactive absorption silencers, are widespread. However, the desire to create silencers with efficiency in a wide range of frequencies leads to a complication of the design and an increase in weight and size parameters. In addition, silencers providing noise reduction over 35 dB create a large aerodynamic resistance to the exhaust gases passing through them (hereinafter referred to as exhaust gas), which leads to high pumping losses in the engine.

One of the promising ways to reduce exhaust emission noise is to use the thermoacoustic effect, which consists in lowering the temperature of the exhaust gas. The thermoacoustic silencer of an automobile engine that implements the aforementioned effect can be used in addition to a basic silencer to fulfill the prospective requirements for the noise level produced by automobile engines. In this case, the overall dimensions of the base muffler can be reduced.

A silencer for an automobile exhaust system is known in the art for reducing sound pressure levels by cooling an exhaust gas (JP 2012154251 A, 08.16.2012). The muffler is based on the use of a thermoacoustic cooling device, which is a thermoacoustic engine installed in the exhaust system of an automobile ICE. Thermoacoustic cooling device consists of a sealed loop pipe with a working fluid, heat exchangers for heating and cooling the working fluid, as well as a regenerative heat exchanger. This design of the muffler has increased overall dimensions of the exhaust system, which makes it difficult to use as part of modern passenger cars, and increases the cost of the exhaust system.

The closest analogue (prototype) of the proposed utility model is a thermoacoustic exhaust silencer (KR 20090042340 A, 04/30/2009), in which exhaust gas noise is reduced by cooling them. The silencer installed in the exhaust system contains a serially connected inlet pipe, a housing that creates resistance to exhaust gas flow, and an exhaust pipe, and a heat exchanger that is mounted on the exhaust pipe and reduces the temperature of the exhaust gas. The body that creates resistance to the exhaust gas flow is a catalytic converter or silencer. The heat exchanger contains exhaust heat dissipation plates made of a ceramic structure with square cells, metal wool, capillary porous materials and special stainless steel nets. The internal space of the heat exchanger used to move the coolant (hereinafter referred to as the coolant) is formed by several radial channels and an annular channel located outside the heat exchange elements. The coolant supply to the heat exchanger is organized from the side of its lateral surface and is directed into one of the radial channels.

Separate execution of a heat exchanger for cooling exhaust gas and a noise reduction device can lead to an increase in the mass and size parameters of a thermoacoustic silencer, since each component must have its own housing, a connecting line and fastening elements.

In addition, the organization of coolant supply and the absence of any guiding elements that regulate the flow of coolant in the channel can cause an uneven distribution of coolant in the space between the heat exchange elements. As a result of this, unequal operating conditions of heat-exchange elements will arise, under which the cooling rate of part of the heat-exchange elements will differ. The result will be a decrease in the efficiency and specific heat output of the heat exchanger as a whole.

The problem solved by the utility model is aimed at developing a thermoacoustic silencer for an automobile engine that reduces exhaust gas noise by cooling them, having compact dimensions, reliable and efficient operation, and at the same time, its level of noise reduction is not inferior to analogues,

moreover, the specified development

should lead to a decrease in fuel consumption in the operating temperature regime (heating), which will increase the efficiency of the engine used with the developed thermoacoustic silencer.

The technical result consists in increasing the efficiency of the thermoacoustic silencer of an automobile engine having smaller dimensions and reduced mass of the structure.

The technical result is achieved by the fact that the thermo-acoustic silencer of an automobile engine, placed in the exhaust system in the direction of their movement, after the catalytic gas converter, includes a heat exchanger through which coolant passes, reducing the temperature of the engine exhaust, and the silencer also includes two chambers extensions, inside of which are installed elements of sound-absorbing material and perforated walls that repeat the configuration of the inner surface of the chambers located m I’m waiting for three heat-exchange sections in turn, which act as a heat exchanger, each of the heat-exchange sections containing heat exchanging pipes inside, filled with porous metal, and outside equipped with inlet and outlet pipes for supplying coolant to the annulus and for draining the coolant from the annulus passing through flow turbulators, while the outlet and inlet nozzles of the adjacent heat exchange sections are connected to each other using a straight pipe, and for supplying and discharging exhaust gas from heat-exchanging sections and expansion chambers, the intake and exhaust manifolds containing an element of sound-absorbing material and a permeable perforated wall that repeat the configuration of the inner surface of the collectors, while heat-exchanging sections, expansion chambers, are introduced into the composition of the thermoacoustic silencer , intake and exhaust manifolds form a single modular housing.

The design of the thermoacoustic silencer also has the following additional differences:

- the intake and exhaust manifolds have a conical shape, which limits the aerodynamic drag during expansion and contraction of the exhaust gas flow, and with respect to the intake manifold, the selected shape also contributes to the uniform distribution of the exhaust gas flow at the inlet to the heat exchange pipes;

- heat exchange sections, expansion chambers, intake and exhaust manifolds have mounting flanges that are connected to each other by fasteners, and a sealing element is located between the flanges, the specified type of fastening of thermoacoustic silencer elements allows the design to be modular with easily replaceable parts, which ensures a cheaper production process and simplifying the replacement of faulty design modules.

The utility model is illustrated by three drawings, which shows a General view of the thermoacoustic silencer of an automobile engine (Fig. 1), a longitudinal section of a muffler (Fig. 2) and a cross section of a third heat-exchange section of a muffler (Fig. 3).

The thermoacoustic silencer consists of three heat-exchange sections 1, each of which is equipped with two mounting flanges 2, sealing 3 and fastening 4 elements and contains inside the heat-exchange pipes 5 filled with porous metal 6. Moreover, the flanges 2 of the heat-exchange sections 1 are also tube sheets for the heat-exchange bundle pipes 5, providing a checkerboard arrangement of heat transfer pipes 5, and the volume limited by the inner surface of the heat exchange section 1 and the outer surfaces of the heat transfer pipes 5 is formed shell space 7 section 1.

Each heat exchange section 1 is equipped with inlet 8 and outlet 9 nozzles installed externally, which are used, respectively, for supplying coolant to the annulus 7 and for draining the coolant from the annulus 7, while ensuring hydraulic connection between the annulus 7 of each heat exchange section 1 of the nozzle 8 and 9 are connected in series using flex 10.

The perpendicular arrangement of the nozzles 8 and 9 relative to the heat exchange tubes 5 provides for the counter-transverse movement of the coolant and exhaust gas.

The composition of the thermoacoustic silencer includes expansion chambers 11 located between the heat exchange sections 1 and provided with mounting flanges 12. Inside the expansion chambers 11, elements of sound-absorbing material 13 and permeable perforated walls 14 are installed that repeat the configuration of the inner surface of the chambers 11.

The composition of the thermoacoustic silencer includes inlet and exhaust manifolds 15 and 16, designed to supply and exhaust exhaust from the heat exchange sections 1 and expansion chambers 11.

Each of the collectors 15 and 16 is equipped with mounting flanges 17 and contains inside an element of sound-absorbing material 18 and a permeable perforated wall 19, which repeat the configuration of the inner surface of the collectors 15 and 16.

The acoustic silencer is located in the exhaust system of the automobile engine after the catalytic converter along the exhaust direction. The selected location of the silencer is due to the need to supply high temperature exhaust gas to the catalyst, which is required for the implementation of redox reactions in the presence of a catalyst.

Exhaust gas having a high residual energy and temperature at the outlet of the engine enters the intake manifold 15 of the muffler, which has an extension of the bore in the longitudinal direction.

Moving along the expanding intake manifold 15, the exhaust stream takes an unbroken form of movement relative to the inner perforated wall 19 of the intake manifold 15, and also has a fairly uniform distribution of the velocity field at the outlet of the intake manifold 15.

The perforated wall 19 of the intake manifold 15 allows the exhaust gas to penetrate into the cavity filled with sound-absorbing material 18. As a result of this, a dissipative reduction in the part of the exhaust gas noise is provided by the loss of acoustic energy by friction in the sound-absorbing material.

Then the exhaust gas flow enters the tube space of the first heat exchange section 1, in which it moves through heat exchange tubes 5 filled with elements of porous metal 6. The conical shape of the intake manifold 15 ensures uniform distribution of the exhaust gas flow at the entrance to the heat exchange tubes 5.

When the exhaust gas moves through the elements of the porous metal 6, an increase in the gas velocity inside the heat exchange pipes 5 occurs, resulting in an increase in the heat transfer coefficient from the exhaust gas to the elements of the porous metal 6 and the walls of the heat exchange pipes 5. As a result, the heat exchange efficiency from the exhaust gas side increases.

Also, the use of porous metal elements 6 makes it possible to increase the thermal power transmitted from the exhaust gas, which becomes possible due to an increase in the heat-exchange surface area.

After passing through the first (by the exhaust gas movement) heat exchange section 1, the exhaust gas enters the first (by the exhaust gas movement) expansion chamber 11, in which the gas flow expands. Through the perforated wall 14 of the expansion chamber 11, a part of the exhaust gas enters the cavity with sound-absorbing material 13, in which the exhaust gas dissipatively decreases.

Next, the exhaust gas stream sequentially passes through the second heat exchange section 1, the second expansion chamber 11 and the third heat exchange section 1, in which the similar processes described above occur.

At the outlet of the third heat exchange section 1, the exhaust gases enter the exhaust manifold 16 having a narrowing of the bore in the longitudinal direction. The selected configuration of the exhaust manifold 16 is aimed at reducing the negative impact that occurs when reducing the area of the bore.

The conical shape of the intake 15 and exhaust 16 collectors can reduce turbulence in the exhaust gas flow, affecting the overall aerodynamic resistance of the thermoacoustic silencer.

To cool the exhaust gas in the heat exchange sections 1, coolant (hereinafter referred to as the coolant) is used, which is supplied to the annular spaces 7 of each heat exchange section 1.

In the heat exchange sections 1, an anti-transverse flow pattern of the coolant relative to the exhaust gas is organized, according to which the coolant through the inlet pipe 8 from the external cooling circuit (not shown in the drawings) first enters the annulus 7 of the third heat exchange section 1, in which the transverse flow around the heat exchange pipes 3.

During movement in the annular space 7, the coolant passes through the flow turbulators (not shown in the drawings), which increase the heat exchange surface area and the heat transfer coefficient between the coolant and the outer surface of the heat transfer tubes 5. The result is an increase in the heat power transmitted by the coolant in the heat exchange sections 1 thermoacoustic silencer.

The joint work of porous metal and flow turbulators allows to achieve a high heat transfer coefficient, which reduces the overall dimensions and the cost of heat exchange sections 1.

To remove the coolant from the annular space of the third heat exchange section 1, an exhaust pipe 9 is used, which is connected to the inlet pipe 8 of the second heat exchange section 1. A flexible pipe 10 is used to connect, simplifying the work during the assembly of a thermoacoustic silencer.

A feature of the mutual arrangement of the inlet 8 and the outlet 9 nozzles on the three heat exchange sections 1 is shown in FIG. 3. The nozzles 8 and 9 have a parallel arrangement with offset axes. As a result of this solution, the movement of the coolant in the cross section of the annular space 7 is consistent with the location of the heat exchange tubes 5, thereby reducing the hydraulic resistance of the annular space 7 of the heat exchange sections 1.

Since the annular spaces 7 of each heat exchange section 1 are hydraulically interconnected, as a result of which the coolant passes successively through each section 1, the processes described for the third heat exchange section 1 are completely repeated for the second and first heat exchange sections 1.

Through the exhaust pipe 9 of the first heat exchange section 1, the coolant returns to the external cooling circuit. Note that said circuit is hydraulically connected to the engine cooling system and the vehicle interior heater.

For the circulation of the coolant through the annular space 7 of the heat exchange sections 1, a circulation pump is used (not shown in the drawings). To control the flow of coolant through the heat exchange sections 1, an electric drive of the circulation pump is used. For example, in the idle and warm-up modes of a cold engine, the coolant flow rate decreases, while in medium and high load-speed modes, the flow rate increases.

The inventive thermoacoustic silencer allows you to achieve the maximum reduction in the noise level of exhaust emissions, up to 5-6 dB, depending on the load-speed mode of the engine. At the same time, the use of thermal power obtained by cooling the exhaust gas ensures a reduction in the engine warm-up time by at least 10%, as well as a reduction in fuel consumption in the heating mode by more than 5%.

The reduction in the overall dimensions of the thermoacoustic silencer is achieved through the use of the compact heat exchanger described above with high specific power, as well as the implementation of the modular design of the thermoacoustic silencer, which uses a series connection of heat exchange sections and expansion chambers without the use of intermediate connecting elements, i.e. using a single (one) modular housings for all elements of a thermoacoustic silencer.

In this way, an increase in the operational efficiency of the thermoacoustic silencer of an automobile engine having smaller dimensions and reduced construction weight is achieved.

In addition, the efficiency of the engine, which is used with the thermoacoustic silencer being developed, is increased due to the recovery of the exhaust gas thermal energy, which reduces the time it takes the engine to reach the operating temperature mode after a cold start, and also reduces the fuel consumption in this mode.

Claims (3)

1. The thermoacoustic silencer of an automobile engine, located in the exhaust system in the direction of their movement, after the catalytic converter, which includes a heat exchanger through which coolant passes, lowering the temperature of the exhaust gases of the engine, characterized in that it includes two expansion chambers inside which are installed elements of sound-absorbing material and perforated walls that repeat the configuration of the inner surface of the chambers located between the three me heat-exchange sections in turn, which act as a heat exchanger, each of the heat-exchange sections containing internally located heat-exchange pipes filled with porous metal, and provided externally with installed inlet and outlet nozzles for supplying coolant to the annulus and for draining the coolant from the annulus passing through flow turbulators, while the outlet and inlet nozzles of the adjacent heat exchange sections are connected to each other by means of a flexible inlet pipe, and for supplying and discharging exhaust gases from heat-exchange sections and expansion chambers, inlet and outlet manifolds are introduced into the composition of the thermoacoustic silencer, which contain an element of sound-absorbing material and a permeable perforated wall inside, which repeat the configuration of the collectors inner surface, while heat-exchange sections, expansion chambers , intake and exhaust manifolds form a single modular housing. 2. Thermoacoustic silencer for an automobile engine according to claim 1, characterized in that the intake and exhaust manifolds are conical in shape. 3. The thermoacoustic silencer of an automobile engine according to claim 1, characterized in that the heat exchange sections, expansion chambers, intake and exhaust manifolds have fixing flanges that are connected to each other by fixing elements, and a sealing element is located between the flanges.

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