RU2633255C1 - Device for catalytic cleaning of exhaust gases of internal combustion engine - Google Patents

Abstract

FIELD: engine devices and pumps.

SUBSTANCE: device contains a catalytic converter consisting of a body with an inlet and an outlet cones, an inlet and an outlet branch pipes and a perforated unit of catalyst and a distributor of exhaust gas flow located inside the body. The exhaust gas flow distributor is made in form of a plate located at the outlet of catalyst unit for displacement along the axis of catalyst converter. The plate is kinematically connected with the outlet cone and/or outlet branch pipe of the body of the catalytic converter by means of a mechanism of movable fastening.

EFFECT: increase efficiency of purification from toxic substances to levels complying with the perspective ecological regulations due to reduction of overall dimensions and extension of service life of devices for toxicity reduction.

4 cl, 9 dwg

Description

The invention relates to the field of ecology of mechanical engineering, in particular to the creation of environmentally friendly engines by catalytic controlled cleaning of exhaust gases of an internal combustion engine from toxic substances.

From the technical literature it is known that when designing catalytic converters, an important task is to ensure uniformity of the exhaust gas flow rate over the entire inlet surface of the catalyst block. When the exhaust gas enters the inlet cone in front of the catalyst block, the flow expands, but the bulk of the gas is directed through the central part of the catalyst block. The pattern of the distribution of the exhaust gas flow rate at the outlet of the catalyst block, obtained from the solution of the gas-dynamic problem by the finite element method, is shown in FIG. 1. As you can see, the velocity distribution over the cross section of the catalyst block has a substantially non-uniform form. In addition, the exhaust gases come in pulses with a speed and, accordingly, a flow variable in time, which exacerbates this unevenness due to the wave process of exposure of the catalyst pores.

A device for purifying exhaust gases is known (Japanese patent JP H 05141234 (A) - 1993-06-08), in which, in order to increase the uniformity of the distribution of the exhaust gas flow over the entire volume of the catalyst block, the inlet and outlet surfaces of the catalyst block are respectively convex and concave.

As calculations showed, a similar shape of the catalyst block significantly improves the uniformity of flow through the catalyst block at low exhaust gas rates. In the modes of operation of the internal combustion engine with a high flow rate, changes in the velocity profile are not significant. In addition, the substrate of the catalyst block of this form is difficult to manufacture, which increases the cost of the catalytic converter.

A device for cleaning exhaust gases is described in patent US 8747760, applicant GM GLOBAL TECH OPERATIONS INC, publ. 06/10/2014, in which, in order to increase the uniformity of the distribution of the exhaust gas flow over the entire volume of the catalytic unit in the first embodiment, the inlet surface of the unit is convex.

As previously indicated, that calculations showed, a similar form of the catalyst block significantly improves the uniformity of flow through the catalyst block at low exhaust gas flow rates. In the modes of operation of an internal combustion engine with a high exhaust gas flow rate, changes in the velocity profile are not significant. In addition, the substrate of the catalyst block of this form is difficult to manufacture, which increases the cost of the catalytic converter.

In a second embodiment of the device of US Pat. No. 8747760, an exhaust gas flow divider is installed in the inlet cone of the catalytic converter. This design allows you to redistribute the flow at all operating modes, but at low costs due to the uneven pulsed flow of exhaust gases, it is difficult to predict their distribution.

The prototype of the proposed technical solution is the device described in patent US 7451594 B2 (application US 2006070375 A1), publ. 04/06/2006, in which the exhaust gas flow distributor is installed in the input cone of the catalytic converter in the form of a plate with curly, sectoral, radially located slots. This embodiment is one of the variants of the known method of increasing the uniformity of the distribution of the exhaust gas flow over the cross section of the catalyst block — the installation of so-called “flow distributors” (impellers) in front of the catalyst block.

The disadvantage of this device is a significant increase in the back pressure of the catalytic converter, especially at high flow rates. In addition, as the flow passes through narrow radial sector cuts located almost perpendicular to the flow, numerous turbulences are formed, which are noise generators.

An object of the invention is to increase the efficiency of purification of exhaust gases of an internal combustion engine from toxic substances to levels that meet promising environmental standards by reducing the size and increasing the resource of devices for reducing toxicity.

The technical problem is solved in that a device for the catalytic purification of exhaust gases of an internal combustion engine, comprising a catalytic converter, consisting of a housing with inlet and outlet cones, inlet and outlet nozzles and located inside the housing of the perforated catalyst block and the exhaust gas distributor, the distributor being made in in the form of a plate located at the exit of the catalyst block with the possibility of movement along the axis of the catalytic converter, while Ting kinematically connected to the output cone and / or the outlet nozzle housing of the catalytic converter by means of movable fastening mechanism.

The mechanism of the movable mounting of the plate is made in the form of a controlled drive made with the possibility of changing the distance of the plate from the output end of the catalyst block depending on the operating mode of the engine.

The mechanism for movable mounting of the plate is made in the form of a spring.

The plate has a convex shape, and the convexity is directed against the flow of exhaust gases.

These signs allow you to solve the technical problem and achieve the following technical results:

- acceleration of the heating of the catalyst block during startup;

- increasing the uniformity of use of the active surface of the catalyst block depending on the flow rate and speed of the exhaust gas;

- reducing the redundancy of the working volume of the catalyst block under unloaded conditions at low exhaust gas rates;

- increase the resource of the catalytic converter.

An apparatus for the catalytic treatment of exhaust gases of an internal combustion engine, a circuit of which is shown in FIG. 2 includes a catalytic converter 1, consisting of a housing with inlet 2 and outlet 4 cones, inlet 8 and outlet 5 nozzles and located inside the housing of the perforated catalyst block 3 and the exhaust gas distributor. The distributor is made in the form of a plate 6, which is located at the exit of the catalyst unit 3 with the possibility of movement along the axis of the catalytic converter and is kinematically connected to the output cone and / or output pipe of the catalytic converter housing using the mechanism 7 of the movable mount.

The mechanism 7 of the movable mounting of the plate is made in the form of a controlled drive made with the possibility of changing the distance of the plate from the output end of the catalyst unit depending on the engine operating mode, for example, in the form of a lever mechanism, the specific implementation of which is determined by the law of movement and is performed according to known dependencies and laws of mechanics. In this case, the drive of the mechanism can be computerized with the possibility of implementing the law of movement, depending on many parameters of the internal combustion engine and its design. This is not the subject of the proposal and for this reason is not described in detail.

The mechanism for moving the plate mount is made in the form of a spring. This design is the simplest.

The plate has a convex shape, and the convexity is directed against the flow of exhaust gases.

When starting, the plate 6 on the mechanism 7 of the movable mount is pressed against the rear cut of the catalyst block 3 and overlaps the central part of the passage section of the catalyst block 3 (Fig. 3). In this case, the peripheral part of the catalyst block 3 is quickly heated by exhaust gases moving at a low speed, and a relatively long heat exchange time and good heat transfer to the catalyst block 3.

In the initial state and at low exhaust costs, the plate 6 on the mechanism 7 of the movable mount is pressed against the rear cut of the catalyst block 3 and overlaps the central part of the passage section of the catalyst block 3 (Fig. 3). In this case, the central part of the catalyst block 3 is not used, the peripheral part of the catalyst block 3, through which the exhaust gases pass, does not create significant back pressure at low flow rates.

The calculated volumetric distribution of the flow velocity in the longitudinal section of the catalytic converter is shown in FIG. 4 and further in the form of gradations of gray from black - minimum speed to white - maximum speed.

With an increase in the flow rate of exhaust gases and, correspondingly, an increase in pressure on the plate, it opens the passage to the exhaust gases, including in the flow regime the central part of the catalyst block 3 (Figs. 5 and 6). At maximum costs, the passage around the plate is fully open.

By changing the surface area of the active part of the catalyst unit 3 (the total surface area of the microchannels of the catalyst unit 3) involved in the process of catalytic neutralization of exhaust gases, the indicated technical results are achieved. When only peripheral zones with lower exhaust gas flow rates and lower temperatures are used in partial modes (in comparison with the maximum speed and / or load modes), the resource of the unit and its efficiency increase, due to which it is possible to reduce its size and / or decrease the load with precious metals .

The mechanism of the movable mount can be made in the form of an elastic element and adjusted to a different pressure drop on the catalyst unit 3. The plate may have a convex shape, and the convexity is directed against the flow of exhaust gases (Fig. 7).

Using the convex shape of the plate, it is possible to achieve a more uniform distribution of the flow rate at the outlet of the catalyst block 3 both at low exhaust gas rates when the plate is pressed against the surface of the catalyst block 3 (Fig. 8) and at high exhaust gas rates when the plate is on a greater distance from the surface of the catalyst block 3 (Fig. 9). Moreover, at low costs, the peripheral part of the catalyst block 3 is actively involved in the catalytic reaction.

Claims (4)

1. A device for the catalytic treatment of exhaust gases of an internal combustion engine, comprising a catalytic converter, consisting of a housing with inlet and outlet cones, inlet and outlet nozzles and located inside the housing of the perforated catalyst block and the exhaust gas distributor, characterized in that the exhaust gas distributor made in the form of a plate located at the exit of the catalyst unit with the possibility of movement along the axis of the catalytic converter, at m plate is kinematically connected to the outlet cone and / or the outlet nozzle housing of the catalytic converter by means of movable fastening mechanism. 2. The device according to p. 1, characterized in that the mechanism of the movable mounting of the plate is made in the form of a controlled drive made with the possibility of changing the distance of the plate from the output end of the catalyst unit depending on the operating mode of the engine. 3. The device according to p. 1, characterized in that the mechanism for movable mounting of the plate is made in the form of a spring. 4. The device according to any one of paragraphs. 1-3, characterized in that the plate has a convex shape, and the convexity is directed against the flow of exhaust gases.

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