FR3106368A1 - VEHICLE CATALYTIC CONTAINER INTENDED TO REDUCE POLLUTANT EMISSIONS - Google Patents

Abstract

The invention relates to a catalytic converter (1) for a vehicle comprising: a catalyst (2) having a longitudinal axis (X), an inner shell (3) surrounding said catalyst (2), an outer shell (6) surrounding said inner shell (3), the outer shell (6) and the inner shell (3) being spaced from one another so as to form between them an annular space (9), A first flange (10) integral with said inner shell (3) and said outer shell (6), a second flange (11) integral with said inner shell (3) and said outer shell (6), a heating device (13), said heating device (13) being disposed in said annular space (9). Figure 1

Description

VEHICLE CATALYTIC CONVERTER DESIGNED TO REDUCE POLLUTANT EMISSIONS

One aspect of the invention relates to a vehicle catalytic converter making it possible to reduce pollutant emissions during cold engine driving phases of the vehicle, in particular an automobile. Another aspect of the invention relates to a vehicle, in particular a motor vehicle, equipped with such a catalytic converter.

It is known from the state of the art of exhaust gas pollution control devices from motor vehicle engines equipped with heating means. Patent application FR 2986561 A1 describes an example of such a pollution control device. It can be seen in the figures of this patent application, a gaseous reducer storage module provided with storage material reservoirs in the form of several cartridges, each provided with heating means whose electrical supply is controlled by control means of the electronic type. These heating means surround part of the external casing of the cartridges and are controlled in temperature by the control means. By heating, the heating means heat the storage material through the wall of the cartridges and thus make it possible to control the desorption of a reducing agent at the appropriate time. Means are also provided for mechanically securing the heating means to a frame also supporting the cartridges. The cartridges and the heating means are installed under the chassis of a vehicle and are covered by a casing. The particular assembly offers the possibility of replacing the cartridges without it being necessary to disassemble the heating means.

If these various solutions proposed in the state of the art can be used for gaseous reducer storage modules, they are however not suitable for an application to a catalytic converter. Indeed, since no protective casing is placed under the vehicle, the application of such technology to a catalytic converter would be a source of significant damage to the heating means of the catalytic converter.

The object of the invention is to overcome the drawbacks of the prior art by proposing a vehicle catalytic converter intended to effectively reduce exhaust gas pollutants while ensuring significant durability of the catalytic converter and its constituent elements.

• Un catalyseur présentant un axe longitudinal,
• Une virole interne entourant le catalyseur,
• Une virole externe entourant la virole interne, la virole externe et la virole interne étant espacée l’une de l’autre de sorte à former entre elles un espace annulaire,
• Un premier flasque solidaire de la virole interne et de la virole externe,
• un deuxième flasque solidaire de la virole interne et de la virole externe, le premier flasque et le deuxième flasque étant espacés l’un de l’autre selon l’axe longitudinal.
• un dispositif de chauffage, le dispositif de chauffage étant disposé dans l’espace annulaire et entre le premier flasque et le deuxième flasque.

To this end, the invention thus relates, in its broadest sense, to a vehicle catalytic converter comprising:

• A catalyst having a longitudinal axis,
• An internal shroud surrounding the catalytic converter,
• An outer shroud surrounding the inner shroud, the outer shroud and the inner shroud being spaced apart from each other so as to form an annular space therebetween,
• A first flange integral with the inner shroud and the outer shroud,
• a second flange integral with the inner shroud and the outer shroud, the first flange and the second flange being spaced from each other along the longitudinal axis.
• a heating device, the heating device being arranged in the annular space and between the first flange and the second flange.

Thanks to the invention, and more particularly to the heating device, it is possible to preheat the catalyst so as to reduce the pollutants of the exhaust gases when the internal combustion engine is still cold, for example at start-up. Furthermore, the heating device is advantageously positioned in a space isolated from the catalyst and from the outside so that the heating device is protected not only from the exhaust gases, but also from the external environment. In other words, the catalyst heating means are protected from shocks and external attacks. This arrangement makes it possible to increase the durability of the heating device.

In addition to the characteristics which have just been mentioned in the previous paragraph, the vehicle catalytic converter according to one aspect of the invention may have one or more additional characteristics among the following, considered individually or in all technically possible combinations.

According to one aspect of the invention, an opening is provided in the outer shroud, the catalytic converter further comprising a flap for closing the opening. Thus, in the event of failure of the heating device, the opening made in the outer shroud thus allows an operator to access the heating device so as to be able to replace it without it being necessary to dismantle the entire catalytic converter.

According to one aspect of the invention, the catalytic converter comprises a compressible flame-retardant element, the compressible flame-retardant element being at least partially compressed between the heating device and the outer shroud. It follows that the heating device is pressed against the outer surface of the inner shroud and is thus held in position. Furthermore, as the heating device is placed in contact with the inner shroud, the heat is propagated efficiently in the inner shroud, then in the catalyst.

According to one aspect of the invention, the fireproof compressible element is also refractory to heat. As a result, the heat emitted by the heater is contained inside the catalytic converter and effectively heats the catalyst.

According to one aspect of the invention, the heating device surrounds at least a portion of the inner shroud.

According to one aspect of the invention, the catalytic converter comprises at least two heating devices. Thus, the dimensions of the heater are such that, depending on the dimensions of the catalyst, it is possible to adapt the number of heaters to the catalyst.

According to one aspect of the invention, the heating device is arranged over the total length of the catalyst. This characteristic makes it possible to heat the total length of the catalyst and thereby increases its efficiency.

According to one aspect of the invention, the heating device is a heating resistor or a network of heating resistors. Such a heating device is simple to implement and does not require any complex element, such as for example a circulation pump.

According to one aspect of the invention, the inner shroud is a flanged shroud. In this implementation, the first flange is formed by a first flange disposed at a first circumferential end of the inner shroud and the second flange is formed by a second flange disposed at a second circumferential end of the inner shroud. This feature makes it possible to reduce the number of parts required to axially close the annular space.

Another aspect of the invention relates to a vehicle comprising a catalytic converter according to at least one of the embodiments of the aforementioned invention, the vehicle further comprising:

a device for programming a catalyst preheating schedule,

a temperature probe constructed and arranged to measure the temperature of the heating device,

a device for automatically controlling the heating device according to said programmed preheating schedule and the temperature of the measured heating device.

The invention and its various applications will be better understood on reading the following description and examining the accompanying figures.

schematically illustrates a vehicle catalytic converter according to one embodiment of the invention.

schematically illustrates an embodiment of an inner shroud that includes a vehicle catalytic converter according to the invention.

schematically represents an embodiment of an opening made in an outer shroud of a vehicle catalytic converter according to the invention.

schematically represents a hatch obstructing an opening made in an outer shroud as illustrated in Figure 3.

schematically represents an embodiment of a catalytic converter according to the invention equipped with a compressible flame-retardant element.

illustrates an embodiment of a heating device that includes a catalytic converter according to the invention.

illustrates another embodiment of a heating device that includes a catalytic converter according to the invention.

represents an implementation of a catalytic converter according to the invention provided with three heating devices.

illustrates an embodiment of a motor vehicle according to the invention equipped with a catalytic converter.

Figure 1 shows a schematic representation of a vehicle catalytic converter according to one implementation of the invention. In this implementation, the catalytic converter 1 comprises a catalyst 2 supported by an internal shroud 3. The catalyst 2 has a longitudinal axis X (in other words an axis of revolution). Catalyst 2 can for example be force-fitted into inner shroud 3. In this case, outer surface 4 of catalyst 2 is in contact with inner surface 5 of inner shroud 3.

The catalytic converter 1 further comprises an outer shroud 6 surrounding the inner shroud 3. They are spaced apart so as to form between them an annular space 9. More particularly, the inner surface 7 of the outer shroud 6 and the outer surface 8 of the inner shroud 3 are spaced apart so as to form between them an annular space 9. In an exemplary embodiment, the inner shroud 3 and the outer shroud 6 are coaxial with the longitudinal axis X. In addition, the inner shroud 3 has a diameter smaller than the diameter of the outer shroud 6. This arrangement makes it possible to form the annular space 9.

The catalytic converter 1 also comprises a first flange 10 integral with the inner shroud 3 and the outer shroud 6. The catalytic converter 1 further comprises a second flange 11 integral with the inner shroud 3 and the outer shroud 6. the fact that the first flange 10 and the second flange 11 are mechanically linked to the inner shroud 3 and to the outer shroud 6. For example, the first and second flanges 10 and 11 can be welded 12, clipped or even screwed onto the inner shroud 3 and on the outer shroud 6.

In this embodiment, the first flange 10 is formed by a first flat ring, the inner circumferential surface of which is welded to the inner shroud 3 and the outer circumferential surface is welded to the outer shroud 6. The second flange 11 is itself formed by a second flat ring, the inner circumferential surface of which is welded to the inner shroud 3 and the outer circumferential surface is welded to the outer shroud 6

It should be noted that the first flange 10 and the second flange 11 are spaced from each other along the longitudinal axis X. In other words, the first flange 10 and the second flange 11 are spaced axially from each other. and axially close the annular space 9. According to embodiments, the annular space may have a circular or oval section.

The catalytic converter 1 comprises a heating device 13. The heating device 13 is arranged in the annular space 9 formed by the inner shroud 3 and the outer shroud 6 and between the first flange 10 and the second flange 11. Thus, the heating device 13 is isolated from the flow of exhaust gases.

The heating device 13 can be formed by a heating resistor or by a network of heating resistors, also called electric heating mat. The heating device 13 is electrically connected to the electrical network of the vehicle. In this exemplary embodiment, the heating device 13 is arranged over the total length of the catalyst 2.

The catalytic converter 1 further comprises an inlet cone 14 and an outlet cone 15 for the exhaust gases. Thus, the flow of exhaust gases 16 is inserted into the inlet cone 14, crosses the catalyst 2 to then exit via the outlet cone 15. Being placed in a closed space constituted by an internal shroud 3, a shroud external 6, a first flange 10 and a second flange 11, the heating device 13 is never in contact with the flow of exhaust gases.

The catalytic converter 1 is therefore fitted with an electric heating device 13 which is controlled by the vehicle control system (not shown). The heating device 13 is also connected to the electrical network of the vehicle (not shown). The rise in temperature of the heating device 13 induces a rise in temperature of the catalyst 2. The rise in temperature takes place by thermal convection from the heating device 13 towards the catalyst 2. This rise in temperature is controlled by the control system of the vehicle and makes it possible to reach the optimum operating temperature of catalyst 2. Thus, in terms of temperature, the pollutants emitted by the cold engine are trapped or eliminated by catalyst 2.

FIG. 2 schematically illustrates an embodiment of an inner shroud that comprises a catalytic converter 1 of a vehicle according to the invention. In this implementation, the inner shroud 3 is a flanged shroud. In other words, the first flange 10 is formed by a first circumferential flange at one end of the inner shroud 3 and the second flange 11 is formed by a second circumferential flange at the other end of the inner shroud 3 This particular arrangement facilitates the assembly of the elements of the catalytic converter 1.

FIG. 3 schematically represents an embodiment of an opening made in an outer shroud of a vehicle catalytic converter according to the invention. This opening 17 allows the introduction of the heating device 13 within the annular space 9 formed between the inner shroud and the outer shroud 6. The electrical connection 18 of the heating device 13 with the electrical network of the vehicle can be made at the through this opening 17. Thus, in the event of a failure, it is possible to replace the heating device 13 without it being necessary to dismantle the catalytic converter 1.

Figure 4 schematically shows a closing hatch obstructing an opening made in an outer shroud as shown in Figure 3. In this case, the catalytic converter 1 comprises a closing flap 19 of the opening 17. This closing flap 19 can for example be secured to the outer shroud 6 by screwing 20 or any other means. Thus, the heating device is not only isolated from the flow of exhaust gases but also from the external environment, namely dust, mud, or stones. This closing hatch 19 is removable so as to be able to allow access to the heating device 13 with a view to replacing it or even repairing it in the event of a failure. The heating device 13 can for example be assembled by screwing to the catalytic converter 1. The electrical connection 18 of the heating device 13 to the electrical network of the vehicle can be made through an orifice made in the closing flap 19.

FIG. 5 schematically represents an embodiment of a catalytic converter according to an implementation of the invention. In this implementation, the catalytic converter 1 comprises a compressible flame-retardant element 21. The compressible flame-retardant element 21 is at least partially compressed between the outer surface 22 of the heating device 13 and the inner surface 7 of the outer shroud 6. This compressible fireproof element 21 makes it possible to place the heating device 13 in contact with the inner shroud 3 so that the heat can propagate effectively in the inner shroud 3, then in the catalyst 2. This compressible fireproof element 21 allows in in addition to holding the heating device 13 in position. Indeed, in one implementation, the heating device 13 can be positioned around the inner shroud 3 and held in position by this fireproof compressible element 21.

The fireproof compressible element 21 can also be refractory to heat. Thus, the heat emitted by the heating device 13 is directed towards the center of the catalyst 2. This feature makes it possible to avoid heat loss outside the outer shroud 3.

FIG. 6 schematically represents an embodiment of a catalytic converter according to an implementation of the invention. In this implementation, the heating device 13 surrounds only a portion of the inner shroud 3. Such an arrangement makes it possible to reduce the cost of the catalytic converter and also to facilitate the assembly of the latter.

FIG. 7 schematically represents an embodiment of a catalytic converter according to an implementation of the invention. In this implementation, the heating device 13 surrounds the entire inner shroud 3. Thus, the heat is evenly distributed around the catalyst 2.

FIG. 8 schematically represents an embodiment of a catalytic converter according to an implementation of the invention. In this implementation, the catalytic converter 1 comprises three heating devices 13. The three heating devices 13 are held in position by a fireproof compressible element 21. Thus, it is possible to use the same type of heating device 13 for catalytic converters with different dimensions.

FIG. 9 schematically represents an example of a motor vehicle fitted with a catalytic converter in accordance with one embodiment of the invention. In this implementation, the vehicle 23 comprises a catalytic converter 1 conforming to at least one of the embodiments presented in support of the preceding figures 1 to 8. The vehicle 23 further comprises a device 24 for programming a preheating schedule for the catalyst 2. Thus, a first programming step via a man-machine interface is carried out by a user of the vehicle. In a different embodiment, this first step can be carried out by a learning algorithm (or artificial intelligence) of the user's habits which, after analyzing the rhythm and start-up cycle, will anticipate the preheating of the catalyst. For example, if the user starts his vehicle every morning at the same time, then the learning algorithm will program a catalyst preheating schedule without the user having to intervene.

The vehicle 23 further comprises a temperature sensor 25 built and arranged to measure the temperature of the heating device 13. This temperature sensor 25 makes it possible to measure the temperature of the catalyst 2.

The vehicle also comprises an automatic piloting device 26 of the heating device 13 depending on the preheating schedule programmed by the user or artificial intelligence and the temperature of the heating device 13 measured by the temperature sensor 25. Thus , for example, in a predetermined time interval, for example 5 minutes before the cold start of the heat engine, the automatic control device 26 of the heating device triggers the electrical supply of the heating device 13 so as to preheat the catalyst 2 prior to the starting of the heat engine of the vehicle 23. The temperature sensor 25 informs the automatic pilot device 26 of the temperature of the catalyst 2 so that the automatic pilot device 26 can effectively regulate the temperature of the catalyst 2.

In general, the catalytic converter according to the aspects of the invention presented above makes it possible to protect the device for heating the exhaust gases by placing it in an isolated volume and also allows the temperature rise of the catalyst by thermal convection. The closing hatch provides access allowing the replacement of the heating device without imposing a complete replacement of the catalytic converter. This arrangement makes it possible to greatly reduce the pollutants during the cold engine running phases of the vehicle. The preheating of the catalyst is in fact ensured by a heating device and does not require any additional element such as for example a circulation pump.

Claims (10)

Vehicle catalytic converter (1) comprising:

• A catalyst (2) having a longitudinal axis (X),
• An inner shroud (3) surrounding said catalyst (2),
• said catalytic converter (1) being characterized in that it further comprises:
• An outer shroud (6) surrounding said inner shroud (3), said outer shroud (6) and said inner shroud (3) being spaced from each other so as to form between them an annular space (9),
• A first flange (10) integral with said inner shroud (3) and said outer shroud (6),
• a second flange (11) integral with said inner shroud (3) and said outer shroud (6), said first flange (10) and said second flange (11) being spaced apart along said longitudinal axis ( X),
• a heater (13), said heater (13) being disposed in said annular space (9) and between said first flange (10) and said second flange (11).

Vehicle catalytic converter (1) according to Claim 1, characterized in that an opening (17) is provided in the outer shroud (6), the said catalytic converter (1) further comprising a hatch (19) for closing the said opening (17). Vehicle catalytic converter (1) according to any one of the preceding claims, characterized in that the catalytic converter (1) comprises a compressible flame-retardant element (21), the compressible flame-retardant element (21) being at least partially compressed between the heater (13) and the outer shroud (6). Vehicle catalytic converter (1) according to Claim 3, characterized in that the flame-retardant compressible element (21) is also heat-resistant. Vehicle catalytic converter (1) according to any one of the preceding claims, characterized in that the heating device (13) surrounds at least a portion of the inner shroud (3). Vehicle catalytic converter (1) according to any one of the preceding claims, characterized in that the catalytic converter (1) comprises at least two heating devices (13). Vehicle catalytic converter (1) according to one of Claims 1 to 5, characterized in that the heating device (13) is arranged over the entire length of the catalyst (2). Vehicle catalytic converter (1) according to any one of the preceding claims, characterized in that the heating device (13) is a heating resistor or a network of heating resistors. Vehicle catalytic converter (1) according to any one of the preceding claims, characterized in that the inner shroud (3) is a shroud with flanged edges, the first flange (10) being formed by a first flanged edge disposed at a first circumferential end of the inner shroud (3) and the second flange (11) being formed by a second flanged edge arranged at a second circumferential end of the inner shroud (3). Vehicle (23), characterized in that it comprises a catalytic converter (1) according to at least one of the preceding claims, said vehicle (23) further comprising:

• a device (24) for programming a preheating schedule for the catalyst (2),
• a temperature sensor (25) constructed and arranged to measure the temperature of the heating device (13),
• an automatic piloting device (26) of said heating device (13) according to said programmed preheating schedule and the temperature of said heating device (13) measured.