FR2700581A1 - Gas exhaust system for IC-engine - Google Patents

Abstract

The exhaust passes through tubes (1-3) which open out to a collector (4). The exhaust gas is cooled directly (20), as it discharges into the collector. The cooling may be by water injected into the collector. The tubes may enter the collector to discharge the gas tangentially along the length of its wall, in a turbulent manner. The injection may be from a nozzle, with a jet (24) arranged parallel to the collector axis (5). In addition, the exhaust collector output is connected to a condensing and washing flexible junction (13).

Description

Engine exhaust system
internal combustion
The present invention relates to an exhaust system of an internal combustion engine, a diesel engine or a gasoline engine.

In such an engine, the gases leaving the cylinders are at a relatively high temperature. It follows that the temperature of the wall of the exhaust manifold as well as that of the gases leaving this exhaust manifold are too high to, without risk of explosion and without special arrangement, allow the use of such a engine in an oxidizing atmosphere, such as for example on oil drilling platforms, or in premises where flammable or explosive pulverulent materials are produced, or certain chemicals.

This is why the exhaust pipes, at the outlet of the cylinders of an internal combustion engine, as well as the exhaust manifold, into which these pipes open, are often surrounded by envelopes in which a coolant circulates. , usually water, thus indirectly cooling the exhaust gases.

When the temperature of the gases reaches significant values, greater than 500 degrees C, or even close to 1000 degrees C, such a cooling process may not be fully effective, except then providing an oversized cooling circuit, with a heat exchanger external cooling water temperature with large radiation area and an additional circulation pump.

The present invention aims to overcome this drawback.

The present invention relates to a gas exhaust system for cylinders of an internal combustion engine comprising, at the outlet of the cylinders, pipes opening into an exhaust manifold and gas cooling means, characterized in that the cooling means include means for direct cooling of the gases flowing in the manifold.

By direct cooling, it is necessary to mean a cooling by direct action, complementary to that of generally provided intermediate elements, such as external envelopes, whereby the efficiency is notably increased.

In the preferred embodiment of the system of the invention, the cooling means comprise means for injecting water into the collector.

Even more preferably, the pipes opening into the manifold so that the gases flow there tangentially along its wall in a swirling movement, the injection means comprise a nozzle for injecting a jet oriented substantially parallel to the axis of the collector.

The water jet is thus sprayed by the exhaust gases from the pipes in a mist which is deposited on the internal wall of the collector and which instantly cools the gases, the wall of the collector and the external cooling water.

Advantageously, a cooled flexible hose is connected at the outlet of the collector, in which the mist condenses and washes the exhaust gases, annihilating the aldehydes, which would otherwise irritate the mucous membranes of the personnel serving, and, when the flexible hose connects the exhaust manifold has a safety output stack, while preserving this stack from premature fouling by carbon dioxide particles washed by the recondensed fog.

The invention will be better understood with the aid of the following description of the preferred embodiment of the exhaust system of the invention, with reference to the appended drawing, in which - Figure 1 is an overall schematic view of the
exhaust system - Figure 2 is an axial sectional view of the manifold
and the system's exhaust manifolds
figure 1 ; - Figure 3 is a cross-sectional view of the
manifold and system exhaust manifold
of Figure 1 and - Figure 4 is an axial sectional view of the flange
direct cooling jet injection from
Figure 1 system.

The combustion gas exhaust system shown in the drawing, here of a diesel engine, comprises, at the outlet of the cylinders, exhaust pipes, of which three, 1, 2, 3 are shown, which open into a manifold 4 with axis 5. The collector 4 is surrounded by an external envelope 6 for the circulation of an indirect cooling fluid, in this case water, just like the pipes 1-3 which are thus each surrounded, an external casing 7 for indirect cooling. The indirect cooling circuit comprises an exchanger or radiator assembly 8 with a filling plug 9, connected, downstream and in series, to a circulation pump 10 and to the external cooling envelopes, those of the pipes 1-3, of the manifold 4 and of other bodies which will be discussed below.

The manifold 4, on one side, is closed by the wall 11 of an injection flange 12 and, on the other side, is opened on a flexible pipe 13 which connects it to a safety stack 14, itself even connected to a rigid outlet pipe 15. The flexible pipe 13 and the safety stack 14 are also each surrounded by an external cooling jacket 16, 17. In the fluid circuit introduced above, external cooling and indirect, the spaces provided by the envelopes 6 of the manifold 4, 16 of the hose 13 and 17 of the stack 14 are in series between the pump 10 and the exchanger 8.

The flexible pipe 13 is here connected to the safety output stack 14 by a rectifier 18 for deflecting the exhaust gases which also surrounds the outer casing 17. As for the stack 14, conventionally, it comprises a series of flat washers suitably spaced from each other.

The pipes 1-3, as best shown in FIG. 3, are connected, inclined on the axis 5, tangentially to the cylindrical wall 4 of the manifold after narrowing 19 aimed at increasing the pressure, and therefore the speed, of the gases of cylinder exhaust.

Thanks to this, the gases, arriving in the collector, flow there tangentially along its wall, in a vortex movement.

The exhaust system comprises a second circuit 20 for cooling the exhaust gases, no longer indirect, but direct. This circuit 20 comprises, in addition to the injection flange 12 and upstream thereof, a reservoir 21, in this case cooling water, and a circulation pump 22 supplied by the reservoir 21. The bottom, or wall, 11 of the flange 12 is pierced with a small through hole 23, here less than half a millimeter in diameter, with an axis parallel to that of the manifold 4, serving as an injection nozzle. Under the action of the pump 22, a water jet 24 can therefore be injected directly inside the collector 4, substantially parallel to its axis 5. The orifice 23 is arranged so that its axis (24) cuts the path of gases flowing from pipes 1-3. I1 can be drilled in an angular or dihedral space of about 15 to 20 degrees extending from a generator of the manifold diametrically opposite to the zone into which the exhaust pipes open 1-3 and on either side of the plane diametral of the collector passing through this generator and this zone. It will also be advantageous for the injection orifice 23 to open into the manifold 4 by a conical flare 25 with an opening substantially equal to 60 degrees.

Thus, the water jet 24 is sprayed by the exhaust gases from the pipes 1-3 in a mist which is deposited on the internal wall of the manifold 4 and which instantly cools these gases, the wall of the manifold and the water from the external cooling circuit 8, 10, 6, 16, 17. In the flexible pipe 13, the mist condenses and washes the exhaust gases by annihilating the aldehydes and preserving the exit safety stack 14 from being crushed premature by carbonic particles. The washed gases and the condensate are discharged through the outlet pipe 15.

It should be noted that if, inadvertently, the engine turns over, there is no risk that the direct cooling water will be sucked through the pipes towards the cylinders and will damage the engine. I1 is so because of the inclination of the tubes on the axis of the manifold and their narrowing increasing the pressure and speed of the gases in their area of connection to the manifold, constituting an obstacle to any possible entry of water.

Claims (7)

1. Gas exhaust system of cylinders of a  internal combustion engine comprising, at the outlet of the  cylinders, tubes (1-3) opening into a  exhaust manifold (4) and means for  gas cooling, characterized in that  the cooling means include means  (20) direct cooling of flowing gases  in the collector (4) 2. Exhaust system according to claim 1, in  which the cooling means (20)  include means (23) for injecting water  in the manifold (4). 3. Exhaust system according to claim 2, in  which the pipes (1-3) opening into the  manifold (4) so that the gases flow there  tangentially along its wall in a  vortex movement, means of injection  (20) include a nozzle (23) for injecting a jet  (24) oriented substantially parallel to the axis (5)  of the manifold (4). 4. Exhaust system according to claim 3, in  which the injection nozzle (23) is arranged so that  its axis (24) intersects the path of gases flowing from  pipes (1-3) in the manifold (4). 5. Exhaust system according to one of claims  2 to 4, in which the manifold (4) is connected in  outlet to a flexible pipe (13) for condensation and  washing. 6. Exhaust system according to one of claims  2 to 5, in which a stack of  exit safety (14). 7. Exhaust system according to one of claims 1  to 6, in which the tubes (1-3) open into  the collector (4), inclined on its axis (5), by a  pressure shrinkage (19) and  increase in gas speed.