Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/021—Introducing corrections for particular conditions exterior to the engine
  • F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
  • F02D41/027—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus
  • F02D41/029—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus the exhaust gas treating apparatus being a particulate filter
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/30—Controlling fuel injection
  • F02D41/38—Controlling fuel injection of the high pressure type
  • F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
  • F02D41/402—Multiple injections
  • F02D41/405—Multiple injections with post injections
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2250/00—Engine control related to specific problems or objectives
  • F02D2250/11—Oil dilution, i.e. prevention thereof or special controls according thereto
• • 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
  • Y02T10/40—Engine management systems

Definitions

• the present invention relates to the field of aftertreatment of exhaust gases and more particularly relates to a post-treatment process of the exhaust gas.
• diesel engines are designed to produce as little exhaust emissions as possible, with the rest to be converted by exhaust aftertreatment systems.
• Diesel engines by their specific operation, emit in their exhaust gas polluting soot or particles.
• a filter called particulate filter
• This filter retains the particles that accumulate within it as and when the engine is used. This accumulation of particles eventually clogs the filter, creating a strong counter pressure to the engine exhaust, which significantly reduces its performance.
• the particles contained in the particulate filter are burned during a regeneration phase. Initialization and maintenance of particle combustion in the filter is achieved by raising the internal temperature of the particulate filter.
• the activation of the various regeneration assistance means is controlled by the engine control computer (ECU) which determines, as a function of several parameters including the soot loading of the particulate filter, the instant of regeneration as well as its duration and the injection parameters during this phase.
• ECU engine control computer
• the thermal necessary for the regeneration of the particle storage elements is obtained by means of additional injections, either during the expansion phase of the cylinder, or directly in the exhaust line.
• the adjustment of the injection is carried out for example by a loop on the temperature at the outlet of the oxidation catalyst, or on the upstream temperature of the particulate filter.
• the exotherm for providing the temperature necessary for the regeneration of the particulate filter is achieved by a post-injection in the combustion chamber of the engine, or by an additional injection directly into the exhaust line called for example injection of the fifth injector.
• the postinjection is performed in the engine cylinders, the introduction of the amount of fuel is achieved through the addition of two post injections.
• the first post injection or near post injection is to inject the fuel after the main injection, the crankshaft having an angle between 20 and 70 ° after top dead center. This injection is intended to burn completely in the cylinder so as to produce a rise in the temperature before the turbine and therefore at the inlet of the catalyst.
• the close post injection thus allows a sensible production of energy on the crankshaft.
• the combustion is only partial and generates a quantity of reducing agents, that is to say the exotherm in the oxidation catalyst.
• the second post injection or post injection remote is to inject the fuel, the crankshaft having an angle between 100 and 150 ° after the top dead center.
• This injection is intended to produce the amount of reducing agents (unburned hydrocarbons (HC)) necessary to reach the input temperature level of the particulate filter required during their treatment in the catalyst (DOC).
• HC unburned hydrocarbons
• DOC catalyst
• the computer adapts the use of the post-injection and / or the fifth injector depending on the operating point.
• WO200757268 proposes for example to divide the post-injection in order to limit the dilution of the fuel in the oil at low flow points.
• JP2007023961 proposes to adapt the post-injection according to the cylinders.
• the document FR2660012 proposes to spray the fuel directly into the particulate filter to expand the use of the fifth injector at low speeds and temperatures, which does not necessarily imply points of low operating speed / load.
• the document US20050000209 proposes a system with a pre-chamber of heating for spraying heated fuel directly into the exhaust line to improve the thermals on certain operating zones.
• the present invention proposes a strategy aimed at reducing the cost of dilution related to the use of post-injection while increasing the area of use of the injector in the exhaust line.
• an object of the invention is a method of post-treatment of the exhaust gases of a combustion engine, characterized in that during the regeneration phases of an oxidation means, at least one post is carried out fuel injection into a combustion chamber coupled to an injection from an exhaust injector disposed in the exhaust line.
• a method combining the use of the fifth injector and the post-injection extends the range of use of the fifth injector and limits dilution at low speed / load.
• the post-injection and the exhaust injection can be carried out on specific operating points, the post-injection and the exhaust injection can be carried out on operating points of low speed / load,
• a close post-injection and at least one remote post-injection can be carried out, the distant post-injection can be divided into two injections,
• the volume of fuel to be injected during the post-injection can be divided into a post-remote injection number.
• the invention also relates to a device for post-treatment of exhaust gases implementing such a method, said device being disposed in an exhaust line of a combustion engine, and comprising a first oxidation means, a second oxidation means, placed downstream of said first oxidation means, a fuel introduction means, arranged upstream of the first oxidation means relative to the direction of flow of the exhaust gas, between the output of the combustion engine and the inlet of the first oxidizing means, characterized in that the first oxidizing means is an oxidation catalyst for a diesel engine.
• the second oxidation means may be a particulate filter.
• the invention also relates to a use of an injection of an injector at the exhaust and at least one remote post-injection during a regeneration phase of an oxidation means, the oxidation means being preferably a particulate filter.
• the invention also relates to a vehicle comprising such a device for aftertreatment of the exhaust gases.
• - Figure 1 is a schematic overview of the device according to the invention.
• - Figure 2 shows an injection diagram depending on the crankshaft angle of the combustion engine, for example for a setting where the main injection "main” is keyed substantially at 0 ° v (crankshaft), the "post-close” substantially at 50 ° v, and the “post-far” substantially at 120 ° v.
• FIG. 1 shows an exhaust gas after-treatment device disposed on a duct or an exhaust line 10, downstream of a combustion engine 4, for example four-cylinder engine equipped with a injection system 5.
• the exhaust line 10 comprises oxidation means 1, 2 formed by a diesel catalytic oxidation catalytic converter called DOC, downstream of which is disposed a particulate filter 2.
• oxidation means 1, 2 formed by a diesel catalytic oxidation catalytic converter called DOC, downstream of which is disposed a particulate filter 2.
• the exhaust line 10 comprises a fuel introduction means 3, such as a fuel injector called the fifth injector, upstream of the catalytic oxidation catalyst 1 relative to the direction of flow of the exhaust gas, between the exit of the combustion engine and the inlet of the oxidation catalyst 1.
• a fuel introduction means 3 such as a fuel injector called the fifth injector
• an exhaust gas post-treatment process comprises a stage in which at least one fuel injection post-injection coupled to an injection from the injector is carried out. 3. At least one post-injection and the exhaust injection are preferably carried out at specific operating points. Indeed, as specified in the description above, in areas where the thermal is sufficient, for example substantially between 3 bars and 13 bars of effective average pressure (PME), the injection from the fifth injector is sufficient.
• PME effective average pressure
• Post-injection and supplemental injection are performed on low speed / load operating zones.
• close post-injection and at least one remote post-injection are performed.
• the post-injection is divided into two distant post injections.
• the use of the fifth injector coupled to this "triple post-injection" advantageously preserves the thermal created by the close post injection while decreasing the dilution related to the post-injection remote.
• the number of remote post injection is given by way of example, the total volume of fuel to be injected during the remote post-injection can be divided into several injections so as to obtain a better homogeneity of the gas mixture. exhaust - fuel and less exchange with cylinder walls.
• This "triple post-injection" allows an increase in the inlet temperature of the engine turbine, which causes an increase in the inlet temperature of the catalytic oxidation catalyst 1 to a level higher than the temperature that allows the priming of the catalyst, which makes it possible to burn the hydrocarbons passing through the catalytic oxidation catalyst 1.
• This exhaust gas aftertreatment process both reduces hydrocarbon emissions and decreases fuel dilution in the oil while ensuring effective regeneration of the particulate filter in low operating zones. /charge.
• Such a method allows a better control of the regeneration of the particulate filter on operating zones at low speed / load, and an efficient treatment of hydrocarbons in these zones by increasing the temperature before turbine and the inlet temperature. from DOC 1.
• This method can advantageously be implemented by any post-treatment device that requires a high thermal associated with a DOC, such as a trap of nitrogen oxide (NOx-T rap) or hydrogen sulphide (H2S-Trap) or other.
• a DOC such as a trap of nitrogen oxide (NOx-T rap) or hydrogen sulphide (H2S-Trap) or other.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Exhaust Gas After Treatment (AREA)
• Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
• Processes For Solid Components From Exhaust (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (3)

Family Cites Families (6)

• 2007
  • 2007-12-21 FR FR0760185A patent/FR2925598A1/fr not_active Withdrawn
• 2008
  • 2008-12-11 WO PCT/EP2008/067278 patent/WO2009083415A1/fr active Application Filing
  • 2008-12-11 EP EP08868902A patent/EP2232034A1/de not_active Withdrawn

Non-Patent Citations (1)

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