ITRE20060047A1 - EXHAUST SYSTEM FOR EXHAUST GAS OF INTERNAL COMBUSTION ENGINES - Google Patents

Abstract

An exhaust gas plant for internal combustion engines, comprising an exhaust evacuation line (7) of the exhaust gases, an antiparticulate filter (1) located so as to intercept the exhaust evacuation line (7), an auxiliary branch (63) connected to the exhaust evacuation line (7) for by-passing the antiparticulate filter (1), diverter means for deviating (64), for selectively deviating the exhaust gas internally of the auxiliary branch (63), and a control system which commands the diverter means for deviating (64) in accordance with a geographical location of a vehicle to which the exhaust gas plant is associated.

Description

DESCRIPTION

of the Italian Patent for Industrial Invention entitled:

"EXHAUST SYSTEM FOR EXHAUST GASES

OF COMBUSTION ENGINES

INTERNAL "

The present invention relates to an exhaust system for the exhaust gases of internal combustion engines, typically of Diesel engines.

More particularly, it relates to an exhaust system which comprises at least one anti-particulate filter, which is adapted to retain the particulate which is allowed to pass by the conventional gas treatment devices placed upstream of the filter itself.

As is known, one of the major sources of pollution of diesel engines for motor vehicles, typically of buses and cars, is the emission into the atmosphere, through the exhaust gases, of particulate matter, i.e. a set of dust and unburnt carbonaceous particles, oxides metallic and similar, which remain suspended in the air. In order to reduce the emission of particulate matter into the atmosphere, in recent years there has been a constant evolution of diesel engines for motor vehicles which, thanks to sophisticated injection systems designed to improve the combustion of diesel fuel, have made it possible to reduce the production of particulate matter.

In addition, passive particulate filters have been developed, fomible both as original equipment and as accessories, which are intended to be installed in the terminal section of the exhaust line, to retain the particulate and prevent its release into the atmosphere.

Generally, said particulate filters are rather delicate, and can be damaged when crossed by exhaust gases at a temperature and / or pressure above certain critical values.

For this reason, exhaust systems fitted with a passive particulate filter usually include an auxiliary branch placed to bypass the filter itself, and means for diverting the flow of exhaust gases into said auxiliary branch, when the temperature is / or the pressure of the gases upstream of them exceed predetermined limit values.

For the same reason, moreover, passive particulate filters cannot even be regenerated on board the vehicle, but need to be disassembled whenever they become clogged, in order to replace them.

A particularly serious drawback of these known filters is in the fact that they become clogged rather quickly, thus requiring frequent maintenance interventions, and high downtime of the vehicles on which they are installed.

However, the applicant noted that the use of the particulate filter is necessary above all in the use of the vehicle in an urban cycle, where the low engine speeds, the frequent accelerations and the numerous stops, generally lead to a worse combustion of the diesel fuel and therefore a higher percentage of particulate matter in the exhaust gases, and where pollution is more harmful due to the high number of vehicles in circulation and the high population density.

Conversely, in the use of the vehicle in an extra-urban cycle, the need to filter the exhaust gases is less felt, both due to the lower quantity of unburnt particles emitted by the engines, and to the lower overall concentration of pollutants and inhabitants in the areas crossed.

The object of the present invention is to make available an exhaust gas exhaust system which allows to selectively use the particulate filter only when necessary, effectively increasing its useful life and thus overcoming the aforementioned drawback of the prior art.

A further object of the invention is to achieve the aforementioned objective in the context of a simple, rational and low-cost solution.

In a general sense, said purposes are achieved by means of an exhaust system which comprises a line for conveying the exhaust gases, a particulate filter placed to intercept said conveying line, an auxiliary branch connected to the conveying line to bypass said particulate filter, and diverting means for selectively diverting the exhaust gases into said auxiliary branch.

According to the invention, the exhaust system comprises a control system which controls said deviating means according to the geographical location of the vehicle with which the exhaust system is associated.

More particularly, said control system controls the deviating means so that the flow of the exhaust gases is engaged to pass exclusively into the particulate filter during urban journeys, where the release of the particulate is more harmful; while it is engaged to pass exclusively in the auxiliary bypass branch during extra-urban journeys.

In this way, the exploitation of the particulate filter is efficiently rationalized, the useful life of which is consequently increased.

According to a preferred embodiment of the invention, the control system comprises a remote device

independent from the vehicle, which is able to interact with an on-board device placed on the vehicle itself to detect the geographical location of the latter, for example by means of a technology such as "telepass", "citypass", satellite or similar.

Alternatively, the control system can simply comprise a device for controlling the diverter means, which can be manually activated by the driver.

Further characteristics and advantages of the invention will become evident from reading the following description provided by way of non-limiting example, with the aid of the figures illustrated in the attached tables, in which:

Figure 1 schematically shows an exhaust system according to the invention;

Figures 2 and 3 show, in longitudinal section, the branch manifold of Figure 1, shown respectively during operation in the urban cycle and during operation in the extra-urban cycle.

The exhaust system 6, object of the present invention, comprises a usual conveyance line 7 designed to guide the exhaust gases coming out of an internal combustion engine 8, typically a Diesel engine, towards the external environment.

Said conveyance line 7 is generally intercepted by a plurality of devices for the treatment of the exhaust gases, and in particular, by a catalytic converter 9 and by a silencer device 10 suitable for being crossed in series by the flow of exhaust gases.

Normally, the silencer device 10 is located downstream of the catalytic muffler 9, with respect to the direction of flow of the exhaust gases.

The conveying line 7 also comprises a three-way branch manifold 60, provided with an inlet duct 61 for the exhaust gas, from which a first outlet terminal 62 and a second outlet terminal 63 branch off.

Said branch manifold 60 is located in the terminal portion of the conveying line 7, downstream of the catalytic converter 9 and of the silencer device 10, with respect to the direction of outflow of the exhaust gases, or integrated in the silencer device 10 itself.

The first terminal 62 of the manifold 60 is intercepted by a passive filter 1, which is designed to filter the exhaust gases in order to retain the particulate allowed to pass by the upstream devices, and in particular, the particulate having dimensions smaller than PM10, that is to say that can be classified among the fine powders.

The second terminal 63, on the other hand, is substantially an auxiliary branch which bypasses said filter 1, so as to prevent the flow of exhaust gases from passing through it.

In the example shown, said second terminal 63 is efferent directly into the atmosphere, in the sense that it flows outside without being intercepted by any other exhaust gas treatment device.

According to the invention, the branch manifold 60 comprises diverter means adapted to selectively divert the exhaust gases towards the terminal 62 or towards the terminal 63.

As shown in Figures 2 and 3, said diverter means comprise a diverter valve formed directly inside the body of the branch manifold 60.

This diverter valve essentially consists of a throttle shutter body 64, hinged inside the manifold 60, which is mechanically connected to actuator means known per se, for example an electric motor, adapted to move it selectively between a first and a second working position.

In the first working position it completely closes the second terminal 63 and opens the first terminal 62 (see fig.2), so that the exhaust gases pass exclusively through the particulate filter 1; while in the second working position it opens the second terminal 63 and completely closes the first terminal 62 (see fig.

3), engaging the entire flow of exhaust gases to exit directly into the atmosphere.

According to the invention, the displacements of the throttle body 64 are controlled by an appropriate control system (not shown), which is able to detect the geographical location of the vehicle to which the exhaust system 6 is associated, and to consequently control the actuator means of the diverter valve.

More specifically, the control system is configured so as to arrange the throttle body 64 in the first working position, when the vehicle is inside an urban center, and to place it in the second working position, when the vehicle is located outside urban centers.

According to a preferred embodiment of the invention, the control system of the diverter valve comprises a remote device, external and independent from the vehicle, which is able to interact by means of radio signals or other electronic signals with an on-board device placed on the vehicle itself. , to detect the geographical location of the latter.

Preferably, the remote device is able to emit the aforementioned signals, which are then picked up and received by the on-board device.

In particular, said remote device can be associated with a fixed station, located for example along an access / exit road from a built-up area, and be able to detect the passage of the vehicle near said fixed station.

Alternatively, said remote device and on-board device can also be part of a satellite localization system of the vehicle, in which a specific map of the vehicle's movement area is implemented, of the type typically used in the so-called "navigators. satellite ".

Finally, a simpler but still effective embodiment of the invention provides that said control system of the diverter valve includes a manual loading device, for example a special button placed inside the passenger compartment, which can be manually activated from the driver.

In this case, at the entrance to the city center, the driver of the vehicle can manually switch the diverter valve to the position in which it forces the exhaust gases to pass through the filter 1; while at the exit of the urban center, the valve can be switched to the position in which it passes the exhaust gases in the auxiliary branch 63, directly towards the outlet into the atmosphere.

Preferably, the control system of the diverter valve, of whatever type it may be, is completed by suitable sensor means (not shown) designed to detect the pressure and / or temperature of the exhaust gases upstream of the manifold 60.

In this way, said control system engages the throttle body 64 to move to the second working position, i.e. to the position in which it prevents the passage of the exhaust gases into the filter 1, if the temperature and / or pressure of the latter is higher. at a predetermined threshold value; this, regardless of the geographical location of the vehicle.

These threshold values have a safety value, in the sense that they prevent the particulate filter 1 from being subjected to too high internal pressures and / or temperatures, which could cause its damage.

Obviously, a person skilled in the art can make numerous modifications to the exhaust system 6 described, without departing from the scope of the invention as claimed below.

Claims (12)

CLAIMS 1. Exhaust system for the exhaust gases of an internal combustion engine, comprising a conveyance line (7) for the exhaust gases, a particulate filter (1) placed to intercept said conveyance line (7), an auxiliary branch (63) connected with the conveyance line (7) to bypass said particulate filter (1), and deviator means (64) to selectively divert the exhaust gases inside said auxiliary branch (63), characterized in that it is comprising a control system which controls said deviator means (63) according to the geographical location of the vehicle with which the exhaust system is associated. 2. System according to claim 1, characterized in that said control system comprises a remote device, external and independent from said vehicle, which is able to interact with an on-board device located on the vehicle itself, to detect the geographical location of the latter. 3. System according to claim 2, characterized in that said remote device is associated with a fixed station, and is able to detect the passage of the vehicle in proximity to said fixed station. 4. System according to claim 2, characterized in that said remote device and on-board device are part of a satellite geographic location system. 5. System according to claim 2, characterized in that said remote device is able to emit signals which are received by said on-board device. 6. System according to claim 2, characterized in that said remote device and on-board device interact by means of electronic signals. 7. System according to claim 2, characterized in that said remote device and on-board device interact by means of radio signals. 8. System according to claim 1, characterized in that said control system comprises a manually operated device adapted to control said diverter means. 9. System according to claim 1, characterized in that said control system of the diverter means (64) is configured in such a way that the latter allow the passage of the exhaust gas exclusively through the particulate filter (1), when the vehicle moves in an inhabited center, and allow the passage of exhaust gases exclusively through the auxiliary branch (63), when the vehicle moves out of inhabited centers. 10. System according to claim 1, characterized in that it comprises detection means suitable for detecting the pressure and / or temperature of the exhaust gases upstream of the particulate filter (1), which detection means are connected to said system control, so that the latter controls the diverter means to prevent the passage of gases through the filter (1) when a predetermined pressure and / or temperature limit value is exceeded. 11. Plant according to claim 1, characterized in that said diverter means comprise at least one diverter valve (64) located in correspondence with the portion of the conveyance line from which said auxiliary branch (63) derives. 12. System according to claim 11, characterized in that said diverter valve comprises an obturator body (64) adapted to occupy a first working position, in which it closes the auxiliary branch (63), and a second working position, in which closes a section (62) of the conveying line (7) that leads to the particulate filter (1).