WO2008017673A1 - System for storing an additive and injecting it into the exhaust gases of an engine - Google Patents

System for storing an additive and injecting it into the exhaust gases of an engine Download PDF

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Publication number
WO2008017673A1
WO2008017673A1 PCT/EP2007/058189 EP2007058189W WO2008017673A1 WO 2008017673 A1 WO2008017673 A1 WO 2008017673A1 EP 2007058189 W EP2007058189 W EP 2007058189W WO 2008017673 A1 WO2008017673 A1 WO 2008017673A1
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WO
WIPO (PCT)
Prior art keywords
additive
tank
injector
venturi
storing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP2007/058189
Other languages
French (fr)
Inventor
François Dougnier
Joel Op De Beeck
Vincent Potier
Jules-Joseph Van Schaftingen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Plastic Omnium Advanced Innovation and Research SA
Original Assignee
Inergy Automotive Systems Research SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Inergy Automotive Systems Research SA filed Critical Inergy Automotive Systems Research SA
Publication of WO2008017673A1 publication Critical patent/WO2008017673A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion
    • F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/22—Control of additional air supply only, e.g. using by-passes or variable air pump drives
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/30—Arrangements for supply of additional air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N2260/00—Exhaust treating devices having provisions not otherwise provided for
    • F01N2260/02—Exhaust treating devices having provisions not otherwise provided for for cooling the device
    • F01N2260/022—Exhaust treating devices having provisions not otherwise provided for for cooling the device using air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
    • F01N2570/14—Nitrogen oxides
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/08—Adding substances to exhaust gases with prior mixing of the substances with a gas, e.g. air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/11—Adding substances to exhaust gases the substance or part of the dosing system being cooled
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1453—Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1493—Purging the reducing agent out of the conduits or nozzle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion
    • F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the system used by most vehicle manufacturers for reducing NOx emissions to the required value generally consists in carrying out a selective catalytic reaction with reducing agents such as urea ("Urea SCR” or selective catalytic reduction using ammonia generated in situ in the exhaust gases by decomposition of urea).
  • reducing agents such as urea ("Urea SCR” or selective catalytic reduction using ammonia generated in situ in the exhaust gases by decomposition of urea).
  • Application WO 03/033111 itself describes a metering system using a pump including a purge device, but which has the drawback of by-passing the pump (and the neighbouring conduit sections) present in the injection line. Such a system is therefore not very reliable. Moreover, recourse to a pump involves a relatively high cost.
  • the present application aims to solve these problems by proposing a system for storing a reducing additive and injecting it into the exhaust gases of an engine, which is simultaneously simple, effective, reliable and inexpensive. It is based on the novel idea of using a venturi-type device to suck up the additive, with the advantage that the devices using this effect are simple, robust and inexpensive and may also be used to purge the conduits of the system.
  • the present invention relates to a system for storing an additive and injecting it into the exhaust gases of an internal combustion engine of a vehicle, said system comprising a tank for storing the additive, an injector and a device for transporting the additive from the tank to the injector via an injection line, said device being of the venturi type and capable of sucking up the amount of additive necessary for optimizing its effect regardless of the location of the additive tank in the vehicle.
  • the additive in question within the scope of the invention is preferably a reducing agent capable of reducing the NOx present in the exhaust gases of internal combustion engines.
  • a reducing agent capable of reducing the NOx present in the exhaust gases of internal combustion engines.
  • ammonia used directly (which has the associated safety and corrosion drawbacks) or generated in situ in the exhaust gases from a precursor such as urea (which enables the aforementioned drawbacks to be avoided).
  • the invention gives good results with urea and, in particular, with aqueous solutions of urea. Eutectic water / urea solutions (comprising 32.5% by weight of urea) are well suited.
  • the present invention may be applied to any internal combustion engine likely to generate NOx in its exhaust gases. It may be an engine with or without a fuel return line (that is to say, a line returning the surplus fuel not consumed by the engine to the fuel tank). It is advantageously applied to diesel engines, and in particular to vehicle diesel engines and particularly preferably to the diesel engines of heavy goods vehicles.
  • the system according to the invention comprises at least one tank intended for storing the additive and at least one injection line intended for carrying the additive to an exhaust pipe of the engine.
  • This line is equipped at its end with an injector that enables the additive to be injected into the exhaust gases.
  • this line also comprises a venturi device for carrying the additive from the additive tank to the injector, this device therefore using a venturi suction effect.
  • the system according to the invention does not comprise a pump or any other device that puts the additive solution under pressure in order to be able to inject it into the exhaust gases.
  • it makes it possible to obtain a suction flow rate such that the additive tank may be positioned anywhere in the vehicle (in other words: the suction effect that this device makes it possible to obtain is sufficient to be able to cover the whole range of flow rates required without having to be assisted by a gravity effect).
  • the flow rates required depend on the amounts required by the catalyst and also the injection frequency and time.
  • the venturi device is preferably capable of providing a flow rate ranging from 0.5 to 100 1/h.
  • the venturi effect may be obtained by any known device using a jet or a stream of fluid capable of creating a suction effect.
  • this fluid is a gas, and more particularly preferably, an "inert" gas, i.e. one that is not very likely or is unlikely to interfere with the SCR reaction.
  • this fluid and the additive will be mixed and injected together into the exhaust gases.
  • It is preferably air (and in particular compressed air, as, for example available on heavy goods vehicles equipped with a compressed-air braking system) or exhaust gases (and in particular pressurized exhaust gases that come, for example, from a turbocharger of the engine).
  • An independent source of compressed air also gives good results.
  • gases from a turbocharger makes it possible to reheat the additive solution by passing through the venturi, which is advantageous.
  • the heat of the gas is indeed useful for vaporizing the urea solution, or even for forming ammonia.
  • venturi devices There are a large number of venturi devices on the market. Within the scope of the invention, it is possible to envisage a water-aspirator type venturi by reversing the gas and liquid inlets.
  • the system according to the invention generally comprises a device that makes it possible to meter the exact amount of additive required.
  • This device may be integrated into the injector (in other words: the injector may be a so- called “active" injector or injector/metering device) or be composed of an additional device such as a metering valve for example.
  • the latter variant is preferred as it makes it possible to separate the metering and injection functions, which increases the reliability of the system and makes it possible to improve the robustness of the injector.
  • the metering valve generally has an opening which is controlled in terms of frequency and time. The preferred choice focuses on piezoelectric or solenoid type valves which can be operated electronically.
  • this metering valve may either directly meter out the amount of additive or meter out the amount of fluid activating the venturi and consequently the flow of additive sucked up.
  • the latter variant is preferred as it in fact allows the saving of a valve: that in the line going from the tank to the venturi.
  • the system according to the invention comprises a computer connected to the metering valve.
  • This computer may be especially dedicated to this function; alternatively it may be integrated into the central computer of the vehicle that in particular controls the operation of the engine (ECU or engine control unit) or into any other computer present in the vehicle (such as that of the fuel system control unit or FSCU).
  • the venturi device may also be used to purge the system, which therefore generally comprises additional valves and/or line sections for this purpose.
  • the system according to the invention comprises a device for cooling the injector.
  • this device may consist of a return of additive to the tank.
  • it is preferably a gas expansion chamber surrounding the injector.
  • this gas is the fluid that drives the venturi, and the chamber is connected to the reserve of this fluid by a line called a cooling line.
  • Figure 1 represents a variant with a metering valve in the line going from the tank to the injector, and Figure 2, a variant where the metering valve is present in the line driving the venturi.
  • Figure 1 represents one variant of the system according to the invention comprising an additive tank (1) containing an ammonia precursor (aqueous (eutectic) solution of urea comprising 32.5% by weight of urea) and an injection line (2) going from the tank (1) to an injector (5) located at the exhaust pipe (7).
  • the injection line (2) comprises a metering valve (6) and a venturi (3) supplied with air compressed by a compressor (4) via a line equipped with a valve (8).
  • the valve(s) (6, 8) are two-position on/off valves.
  • valve (8) In normal (injection of additive) operating mode, the valve (8) is open between the compressor (4) and the venturi (3), and the metering valve (6) is open between the tank (1) and the venturi (3). The amount of solution injected is measured out using the metering valve (6).
  • the purge of the lines is carried out according to the following steps:
  • Step 1 closing the valve (6) between the tank (1) and the venturi (3); sending compressed air into the venturi (3) through the valve (8) allowing the portion of the line (2) downstream of the valve (6) up to the injector (5) to be purged.
  • Step 2 turning the valves (6) and (8) so as to purge the portion of the line
  • Figure 2 represents a variant where the metering valve (6) is this time present in the compressed-air line and therefore makes it possible to indirectly control the amounts of ammonia precursor solution injected.
  • the injector (5) is equipped with an expansion chamber (9) enabling it to be cooled following the expansion of the gases transported from the compressor (4) by the conduit (10).
  • the injector (5) and its cooling chamber (9), the venturi device (3) and the line (2) are purged with compressed air when the valve (6) connects the compressor (4) with a conduit (11) linked to the injector (5) and by doing this, injects compressed air through the injector (5) then through the venturi device (3), then through the line (2) up to the tank (1).

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

System for storing an additive and injecting it into the exhaust gases of an internal combustion engine of a vehicle, said system comprising a tank (1) for storing the additive, an injector (5) and a device (3) for transporting the additive from the tank to the injector via an injection line (2), said device being of the venturi type sing an exhaust gas from a urbo charge connected to the engine and capable of sucking up the amount of additive necessary for optimizing its effect regardless of the location of the additive tank in the vehicle.

Description

System for storing an additive and injecting it into the exhaust gases of an engine
With the Euro IV standard on exhaust emissions from vehicles soon coming into effect, devices for pollution control of NOx (or nitrogen oxides) must be put in place.
The system used by most vehicle manufacturers for reducing NOx emissions to the required value generally consists in carrying out a selective catalytic reaction with reducing agents such as urea ("Urea SCR" or selective catalytic reduction using ammonia generated in situ in the exhaust gases by decomposition of urea).
In order to do this, it is necessary to equip the vehicles with a tank containing a urea solution and also a device for metering the amount of urea to be injected into the exhaust line.
With a view to facilitating the operation and re-starting of such a system in case of freezing, it is advantageous to periodically purge the conduits that have transported the urea for the purpose of clearing them of liquid additive deposits, which are capable of solidifying in the event of freezing. In particular, it is advantageous to purge the line connecting the additive tank to the injector (or injection line). This also makes it possible to avoid using a complex device for reheating the urea conduits. Such a purge device is the subject of Application WO 2006/064028 in the name of the Applicant. As regards the metering and injection of the urea solutions into the exhaust gases, several systems have been described in the prior art.
Thus, Application US 2002/0081239 itself describes several solutions which are respectively: metering by simple gravity; use of a pump; and the fact of pressurizing the tank either via compressed air, or by mechanical pressure exerted on a flexible wall of the tank. This application does not provide a purge system.
Application WO 03/033111 itself describes a metering system using a pump including a purge device, but which has the drawback of by-passing the pump (and the neighbouring conduit sections) present in the injection line. Such a system is therefore not very reliable. Moreover, recourse to a pump involves a relatively high cost. The present application aims to solve these problems by proposing a system for storing a reducing additive and injecting it into the exhaust gases of an engine, which is simultaneously simple, effective, reliable and inexpensive. It is based on the novel idea of using a venturi-type device to suck up the additive, with the advantage that the devices using this effect are simple, robust and inexpensive and may also be used to purge the conduits of the system. It should be noted in this regard that the aforementioned US application mentions the use of a venturi effect but only for mixing the urea with compressed air, where appropriate, and not for sucking up the solution from the tank. Therefore, the system which is described therein must either be equipped with an additional suction means (for example, a pump), or be positioned in the vehicle so that the solution can flow by gravity (see § [0036]), which is constricting from a system architecture point of view.
For this purpose, the present invention relates to a system for storing an additive and injecting it into the exhaust gases of an internal combustion engine of a vehicle, said system comprising a tank for storing the additive, an injector and a device for transporting the additive from the tank to the injector via an injection line, said device being of the venturi type and capable of sucking up the amount of additive necessary for optimizing its effect regardless of the location of the additive tank in the vehicle.
The additive in question within the scope of the invention is preferably a reducing agent capable of reducing the NOx present in the exhaust gases of internal combustion engines. Advantageously it is ammonia used directly (which has the associated safety and corrosion drawbacks) or generated in situ in the exhaust gases from a precursor such as urea (which enables the aforementioned drawbacks to be avoided). The invention gives good results with urea and, in particular, with aqueous solutions of urea. Eutectic water / urea solutions (comprising 32.5% by weight of urea) are well suited.
The present invention may be applied to any internal combustion engine likely to generate NOx in its exhaust gases. It may be an engine with or without a fuel return line (that is to say, a line returning the surplus fuel not consumed by the engine to the fuel tank). It is advantageously applied to diesel engines, and in particular to vehicle diesel engines and particularly preferably to the diesel engines of heavy goods vehicles. The system according to the invention comprises at least one tank intended for storing the additive and at least one injection line intended for carrying the additive to an exhaust pipe of the engine. This line is equipped at its end with an injector that enables the additive to be injected into the exhaust gases. According to the invention, this line also comprises a venturi device for carrying the additive from the additive tank to the injector, this device therefore using a venturi suction effect. In particular, the system according to the invention does not comprise a pump or any other device that puts the additive solution under pressure in order to be able to inject it into the exhaust gases. In addition, it makes it possible to obtain a suction flow rate such that the additive tank may be positioned anywhere in the vehicle (in other words: the suction effect that this device makes it possible to obtain is sufficient to be able to cover the whole range of flow rates required without having to be assisted by a gravity effect). The flow rates required depend on the amounts required by the catalyst and also the injection frequency and time. In particular, the venturi device is preferably capable of providing a flow rate ranging from 0.5 to 100 1/h. According to the invention, the venturi effect may be obtained by any known device using a jet or a stream of fluid capable of creating a suction effect. Preferably, this fluid is a gas, and more particularly preferably, an "inert" gas, i.e. one that is not very likely or is unlikely to interfere with the SCR reaction. Indeed, by definition this fluid and the additive will be mixed and injected together into the exhaust gases. It is preferably air (and in particular compressed air, as, for example available on heavy goods vehicles equipped with a compressed-air braking system) or exhaust gases (and in particular pressurized exhaust gases that come, for example, from a turbocharger of the engine). An independent source of compressed air also gives good results. It should however be noted that the use of gases from a turbocharger makes it possible to reheat the additive solution by passing through the venturi, which is advantageous. The heat of the gas is indeed useful for vaporizing the urea solution, or even for forming ammonia.
There are a large number of venturi devices on the market. Within the scope of the invention, it is possible to envisage a water-aspirator type venturi by reversing the gas and liquid inlets.
The system according to the invention generally comprises a device that makes it possible to meter the exact amount of additive required. This device may be integrated into the injector (in other words: the injector may be a so- called "active" injector or injector/metering device) or be composed of an additional device such as a metering valve for example. The latter variant is preferred as it makes it possible to separate the metering and injection functions, which increases the reliability of the system and makes it possible to improve the robustness of the injector. The metering valve generally has an opening which is controlled in terms of frequency and time. The preferred choice focuses on piezoelectric or solenoid type valves which can be operated electronically.
It should be noted that this metering valve may either directly meter out the amount of additive or meter out the amount of fluid activating the venturi and consequently the flow of additive sucked up. The latter variant is preferred as it in fact allows the saving of a valve: that in the line going from the tank to the venturi.
Usually, the system according to the invention comprises a computer connected to the metering valve. This computer may be especially dedicated to this function; alternatively it may be integrated into the central computer of the vehicle that in particular controls the operation of the engine (ECU or engine control unit) or into any other computer present in the vehicle (such as that of the fuel system control unit or FSCU).
According to one preferred variant of the invention, the venturi device may also be used to purge the system, which therefore generally comprises additional valves and/or line sections for this purpose. According to another preferred variant of the invention, which may or may not be used in conjunction with the previous one, the system according to the invention comprises a device for cooling the injector. In the case of an active (metering) injector, this device may consist of a return of additive to the tank. However, within the scope of the invention, it is preferably a gas expansion chamber surrounding the injector. According to one particularly advantageous variant, this gas is the fluid that drives the venturi, and the chamber is connected to the reserve of this fluid by a line called a cooling line.
The purge and/or cooling of the injector are also controlled by the aforementioned computer, if necessary. The present invention is illustrated, in a non-limiting manner, by Figures 1 and 2, which each relate to a different variant. Figure 1 represents a variant with a metering valve in the line going from the tank to the injector, and Figure 2, a variant where the metering valve is present in the line driving the venturi. In these figures, identical numbers denote identical components. Figure 1 represents one variant of the system according to the invention comprising an additive tank (1) containing an ammonia precursor (aqueous (eutectic) solution of urea comprising 32.5% by weight of urea) and an injection line (2) going from the tank (1) to an injector (5) located at the exhaust pipe (7). The injection line (2) comprises a metering valve (6) and a venturi (3) supplied with air compressed by a compressor (4) via a line equipped with a valve (8). The valve(s) (6, 8) are two-position on/off valves.
In normal (injection of additive) operating mode, the valve (8) is open between the compressor (4) and the venturi (3), and the metering valve (6) is open between the tank (1) and the venturi (3). The amount of solution injected is measured out using the metering valve (6). The purge of the lines is carried out according to the following steps:
Step 1 : closing the valve (6) between the tank (1) and the venturi (3); sending compressed air into the venturi (3) through the valve (8) allowing the portion of the line (2) downstream of the valve (6) up to the injector (5) to be purged. Step 2: turning the valves (6) and (8) so as to purge the portion of the line
(2) between the valve (6) and the tank (1) via injection of compressed air to the valve (8), then to the metering valve (6) and next to the tank (1).
Figure 2 represents a variant where the metering valve (6) is this time present in the compressed-air line and therefore makes it possible to indirectly control the amounts of ammonia precursor solution injected.
The injector (5) is equipped with an expansion chamber (9) enabling it to be cooled following the expansion of the gases transported from the compressor (4) by the conduit (10).
The injector (5) and its cooling chamber (9), the venturi device (3) and the line (2) are purged with compressed air when the valve (6) connects the compressor (4) with a conduit (11) linked to the injector (5) and by doing this, injects compressed air through the injector (5) then through the venturi device (3), then through the line (2) up to the tank (1).

Claims

C L A I M S
1. - System for storing an additive and injecting it into the exhaust gases of an internal combustion engine of a vehicle, said system comprising a tank for storing the additive, an injector and a device for transporting the additive from the tank to the injector via an injection line, said device being of the venturi type using an exhaust gas from a turbocharger connected to the engine and being capable of sucking up the amount of additive necessary for optimizing its effect regardless of the location of the additive tank in the vehicle.
2. - System according to the preceding claim, characterized in that the venturi device is capable of providing a flow rate ranging from 0.5 to 100 1/h.
3. - System according to either one of the preceding claims, characterized in that it comprises a metering valve.
4. - System according to the preceding claim, characterized in that the metering valve is positioned in a line that connects the venturi to a reserve of fluid driving it.
5. - System according to any one of the preceding claims, characterized in that the venturi device also enables the system to be purged.
6. - System according to any one of the preceding claims, characterized in that it comprises a device for cooling the injector.
7. - System according to the preceding claim, characterized in that the cooling device is a gas expansion chamber surrounding the injector.
PCT/EP2007/058189 2006-08-08 2007-08-07 System for storing an additive and injecting it into the exhaust gases of an engine Ceased WO2008017673A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0607209 2006-08-08
FR0607209A FR2904855A1 (en) 2006-08-08 2006-08-08 SYSTEM FOR STORING AND INJECTING AN ADDITIVE IN EXHAUST GASES OF AN ENGINE

Publications (1)

Publication Number Publication Date
WO2008017673A1 true WO2008017673A1 (en) 2008-02-14

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Country Status (2)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013098253A1 (en) * 2011-12-27 2013-07-04 Robert Bosch Gmbh Metering module and exhaust gas after-treatment device
EP2685060A1 (en) * 2012-07-09 2014-01-15 Albonair GmbH Reductant metering system with emptying of the reductant line after the end of metering
WO2014188056A1 (en) * 2013-05-24 2014-11-27 Wärtsilä Finland Oy Exhaust system
US9051864B2 (en) 2009-04-16 2015-06-09 Inergy Automotive Systems Research (Société Anonyme) System and process for storing an additive and injecting it into the exhaust gases of an engine

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Publication number Priority date Publication date Assignee Title
GB995835A (en) * 1963-05-29 1965-06-23 Allis Chalmers Mfg Co Treating exhaust gases of internal combustion engines
US3712065A (en) * 1970-12-04 1973-01-23 Clevepak Corp Antipollution exhaust system for an internal combustion engine
DE19806265C1 (en) * 1998-02-16 1999-07-22 Siemens Ag Low-maintenance system dosing urea solution into exhaust or effluent gases, for selective catalytic reduction
DE10129592A1 (en) * 2000-08-02 2002-02-21 Ford Global Tech Inc Reductant delivery for vehicle exhaust system includes liquid metering unit in sealed control volume of casing, mixing chamber and compressed air inlet
EP1669567A1 (en) * 2003-09-19 2006-06-14 Nissan Diesel Motor Co., Ltd. Exhaust gas purification device of engine
WO2006066043A1 (en) * 2004-12-15 2006-06-22 Donaldson Company, Inc. Control for an engine exhaust treatment system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB995835A (en) * 1963-05-29 1965-06-23 Allis Chalmers Mfg Co Treating exhaust gases of internal combustion engines
US3712065A (en) * 1970-12-04 1973-01-23 Clevepak Corp Antipollution exhaust system for an internal combustion engine
DE19806265C1 (en) * 1998-02-16 1999-07-22 Siemens Ag Low-maintenance system dosing urea solution into exhaust or effluent gases, for selective catalytic reduction
DE10129592A1 (en) * 2000-08-02 2002-02-21 Ford Global Tech Inc Reductant delivery for vehicle exhaust system includes liquid metering unit in sealed control volume of casing, mixing chamber and compressed air inlet
EP1669567A1 (en) * 2003-09-19 2006-06-14 Nissan Diesel Motor Co., Ltd. Exhaust gas purification device of engine
WO2006066043A1 (en) * 2004-12-15 2006-06-22 Donaldson Company, Inc. Control for an engine exhaust treatment system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9051864B2 (en) 2009-04-16 2015-06-09 Inergy Automotive Systems Research (Société Anonyme) System and process for storing an additive and injecting it into the exhaust gases of an engine
WO2013098253A1 (en) * 2011-12-27 2013-07-04 Robert Bosch Gmbh Metering module and exhaust gas after-treatment device
EP2685060A1 (en) * 2012-07-09 2014-01-15 Albonair GmbH Reductant metering system with emptying of the reductant line after the end of metering
WO2014188056A1 (en) * 2013-05-24 2014-11-27 Wärtsilä Finland Oy Exhaust system

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