FR2463851A1 - - Google Patents

Abstract

EXHAUST DEVICE FOR INTERNAL COMBUSTION ENGINE, SHAPED FROM A MATERIAL OF HIGH THERMAL CONDUCTIVITY, INCLUDING AN INLET AND OUTLET PORT AND CHARACTERIZED BY THE FACT THAT SEVERAL THIN BRANCHED 4A, 4B, 4C, 4D DUCTS ARE PREPARED BETWEEN INPUT PORT 2 AND OUTPUT 3 SO AS TO DIVIDE THE EXHAUST GAS COMING FROM THE INPUT PORT INTO PARTIAL CURRENTS AND TO JOIN THESE PARTIAL CURRENTS AT THE OUTPUT, THE DUCTS BRANCHES BEING SPACED BETWEEN THEM SO AS TO ALLOW ATMOSPHERIC AIR TO PASS THROUGH THE SPACES CONTAINED BETWEEN THEM, THESE BRANCHED DUCTS HAVING A DIFFERENT LENGTH FROM ONE OF THE OTHERS.

Description

The invention relates to an exhaust device designed to be attached to

an engine exhaust manifold

internal combustion.

  In an exhaust device of the above type, it is desirable to allow the smooth flow of exhaust gas, not to create significant resistance and also

  reduce the noise of the exhaust gas released into the

mosphere. However, it is very difficult to fully and simultaneously fulfill the above conditions, since

  we could get a reduction in exhaust noise

  by creating a relatively large resistance in the exhaust system. For example, in a known exhaust system, complicated flow passages have the shape of a labyrinth so as to regularize

  the pulsation of the engine exhaust gas and thus, to re-

  reduce the noise of the gas released into the atmosphere. This reduction-

noise is practically proportional to the compli-

  cation of flow passages. However, the complicated flow passages oppose a smooth flow of the exhaust gas by creating a significant resistance in the exhaust device so that the counter pressure opposite the engine in the exhaust device becomes

  excessive, causing loss of engine power.

  It is therefore an object of the invention to provide an exhaust device for an internal combustion engine which can satisfactorily reduce noise.

  exhaust gas without creating a high back pressure.

  Another object is to provide an exhaust device for an internal combustion engine which is very structurally

  simple and little storytelling.

According to the invention, an escape device is proposed.

Pement for internal combustion engine, formed of a material of high thermal conductivity, having an inlet port and an outlet port and characterized in that several thin branched conduits are provided between

the inlet and the outlet so as to divide

  ser in partial currents the exhaust gas coming from the inlet orifice and to join these partial currents to the outlet orifice, the branched conduits being spaced apart so as to allow atmospheric air to

  pass through the spaces between them, these branched ducts

  each having a length different from each other.

  A preferred embodiment is characterized in that each of the inlet and outlet orifices is a narrow opening elongated transversely, that each of the

  branched ducts has a practically rectan section

flattened gular and the branched ducts are curved

outwards with different radii of curvature.

Other objects and features of the invention appear

tront in the detailed description below, relating to

  preferential modes of execution and referring to the

attached sins on which:

  Figure 1 is a cutaway perspective of a device

  tif according to a first embodiment of the invention; Figure 2 a section along Figure II-II of Figure 1; Figure 3 an explanatory view showing the series connection of the devices, according to a second embodiment of the invention and Figure 4 a side view of the devices of the

  Figure 3, incorporated into the exhaust pipe of an automobile.

  We will consider Figures 1 and 2 which show a pre-

  mier mode of execution of the invention; an escape device

  pement 1 is formed of a material of high thermal conductivity such as an aluminum alloy. In this embodiment, the device 1 is formed from thin sheets of

  so as to increase the heat transmission. The disposi-

  tif 1 has an inlet port 2 and an outlet port 3, relatively flattened and elongated transversely, located

  in the same horizontal plane. Entrance 2 communicates

  as with the outlet 3 by four branched conduits 4a to 4d which are separated from each other independently in their

  intermediate part between the inlet and outlet openings

  tie but meet in the vicinity of the inlet ports 2

  and outlet 3. At least three conduits 4b to 4d are light-

curved with different radii of curvature so that all the conduits. have different lengths L to L4 between the inlet 2 and outlet 3 ports. In this device, each duct has a flattened rectangular section and is spaced from the adjacent duct by a spacing

arched 5.

The exhaust device 1 of the invention is designed to be incorporated into the exhaust pipe of an automobile internal combustion engine. For example, the orifice

  2 of the exhaust device 1 is connected to a collar

engine exhaust reader by a fitting (not shown

felt) with a circular opening connected to the outlet

  exhaust manifold and a flattened opening

  linked to the inlet orifice 2 of the device according to the invention.

  The exhaust device according to the invention must be re-

  related to the automobile in a place where it is subjected to a re-

  cooling by a draft when the automobile is traveling

the.

  In such a device, the hot exhaust gas comes out

  as much of the engine exhaust manifold enters the ori-

  input port 2 of the device and branches into four

  partial rants passing through the four conduits 4a to 4d.

  Since the exhaust system is subjected to cooling by an air current, the exhaust gas which passes through the branched conduits 4a to 4d is cooled by air. The cooling effect of the present device is remarkable because the branched conduits 4a to 4d have a relatively thin and flattened shape and are formed of a material of high thermal conductivity and separated from each other so as to allow air to pass freely by the spacings. As a result of this cooling effect, the pressure of the exhaust gas arriving at the outlet

3 of the device according to the invention is remarkably dimi-

cloud. Thus, the back pressure applied to the engine by the exhaust pipe is effectively reduced which makes

  that it becomes possible to increase the engine power.

  Furthermore, since the pressure of the exhaust gas is reduced in the device, the thermal expansion of the exhaust gas discharged into the atmosphere through the outlet port 3 of the device is not as great as in the conventional exhaust system, so that noise

generated is decreased in this device.

In addition, the exhaust gas entering the orifice

  dbntrée 2 of the device 1 is divided into four streams by-

tial by branched conduits 4a to 4d which have different lengths. Consequently, the partial streams of the exhaust gas have different wave phases when they pass through the conduits and these phases interact at the outlet orifice 3 of the device. It is very easy to preset the length of the conduits 4a to 4d so that

  the amplitude of the mixed wave at the outlet orifice 3 of the device

  positive becomes much lower than that which exists at the

entry fee. This results in a further decrease in the

  noise of exhaust gas released into the atmosphere.

  In the exhaust device according to a first embodiment of the invention, the branched conduits 4b to 4d

are slightly curved with different radii of curvature

so that no noticeable pressure drop is

  gendered by the device. This structure according to the invention

allows the serial connection of several devices according to the

vention.

  Figures 2 and 3 show a second embodiment of the invention in which three exhaust devices 1

  according to the invention are connected in series to the exhaust manifold

  pation 5 of the motor 6. In the series connection of the devices

  positive according to the invention, the intermediate device 1b is turned upside down, relative to FIG. 1, and it is connected in such a way that the inlet orifice 2 of the intermediate device 1b communicates directly with the outlet orifice 3 of the adjacent device located in

upstream, while the outlet orifice 3 of the inter-

medium lb communicates directly with the inlet orifice 2 of the other adjacent device, located downstream. Preferably, the devices 1a to 1c in series are mounted below the automobile 7 and several deflectors 8 are provided on the devices so as to deflect the air flow towards

  horizontal against the outer surfaces of the ducts

mified devices according to the invention and to strengthen the ef-

cooling effect while the automobile is running.

- As can be understood from the description of the second mode

  In execution, the series connection of the devices according to the invention has the effect of cooling the exhaust gas much more, thereby greatly reducing the noise of the exhaust gas in the atmosphere. The interactions between the partial streams of the exhaust gas are also cumulatively increased while the exhaust gas passes through the branched conduits 4a to 4d. As a result, it becomes possible to significantly reduce the noise of the exhaust gas.

by presetting the length of the conduits so that the ampli-

  study of the mixed waves of the exhaust gas discharged into the

mosphere can become minimal.

Thus, the exhaust device according to the invention can replace a relatively expensive conventional silencer, which leads to an increase in the power of the engine.

  and lower fuel consumption.

  The invention has been described in connection with embodiments

  preferential but we can bring it, within the framework of the

  vention, many modifications.

Claims (5)

1. Exhaust device for combustion engine internal, formed of a material of high thermal conductivity that, comprising an inlet and an outlet and characterized in that several thin branched conduits are provided between the inlet and the outlet so as to divide the exhaust gas into partial streams coming from the inlet and bringing these   partial currents at the outlet, the branch ducts   being spaced apart so as to allow atmospheric air to pass through the spaces between them, these branched conduits having a different length each others.   2. Device according to claim 1, characterized in that each of the inlet and outlet orifices is a narrow opening elongated transversely, that each branched ducts has a practically rec-   tangled flattened and the branched conduits are bent outwards with different radii of curvature. 3. Device according to one of claims l't -, ca- characterized by the fact that it also includes several flectors attached to it so as to deflect the air flow against the external surfaces of the branched conduits, while an automobile equipped with the device is moving.   4. Device according to one of claims 2 and 3, ca-   characterized by the fact that the inlet orifice, the outlet orifice and the branched conduits form cor5s between them and are   practically located in the same plane.   5. Device according to one of claims 1 to 4, ca- characterized by the fact that it is connected in series with one or   several other devices of the same structure.