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
  • 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
  • F01N9/00—Electrical control of exhaust gas treating apparatus
  • F01N9/002—Electrical control of exhaust gas treating apparatus of filter regeneration, e.g. detection of clogging
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2200/00—Input parameters for engine control
  • F02D2200/02—Input parameters for engine control the parameters being related to the engine
  • F02D2200/08—Exhaust gas treatment apparatus parameters
  • F02D2200/0812—Particle filter loading
• • 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
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
  • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
  • F02D41/1466—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being a soot concentration or content
  • F02D41/1467—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being a soot concentration or content with determination means using an estimation
• • 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
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
  • F02D41/1473—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the regulation method
  • F02D41/1475—Regulating the air fuel ratio at a value other than stoichiometry
• • 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
• • 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 refers to the field of exhaust gas treatment lines (ATS: After Treatment Systems) of the type based on PM-CAT filters, also known as POC (Particulate Oxidation Catalyst), PM-Kat or Flow-through filters (FTF) or Open particulate filters or Partial flow filter (PFF) or Partial filter technology (PFT) or PM oxidation catalyst or PM filter catalyst.
• PM-CAT filters also known as POC (Particulate Oxidation Catalyst), PM-Kat or Flow-through filters (FTF) or Open particulate filters or Partial flow filter (PFF) or Partial filter technology (PFT) or PM oxidation catalyst or PM filter catalyst.
• PM-CAT filters In order to capture the carbonaceous particulate matter.
• PM-CAT filters unlike the DPF filters (Diesel particulate filter) , are open filters, in the sense that the alveoli made in the body of the filter are open and allow the passage of the gases in any saturation condition of the filter itself.
• the particulate matter is actually filtered by centrifugation, which causes the particulate matter to collide with and to settle within the porous walls of the alveoli, where it gets trapped.
• PM- Metalit TM of Emitec. It comprises alternating layers of corrugated metal foil and porous sintered metal fleece. The corrugated foil is formed to direct the gas flow so it impinges onto the metal fleece. The internal surfaces of the PM-Cat do not have catalyst coatings.
• the filtering power of PM-CAT filters is between 50% and 90%, thus they are to able to retain all the particulate matter until the alveoli are full the gas can flow through the filter without being treated.
• both the PM-CAT and the DPF filters are coupled with a DOC (Diesel Oxidation Catalyst), which is arranged upstream of the respective filter and promotes the production of O 2 , in order to facilitate a natural reaction of the first type, namely promoting the reaction of the carbonaceous soot with the O 2 in order to generate CO/C02 according to the reaction
• DOC Diesel Oxidation Catalyst
• Such reaction is said to occur naturally or passively when the filter reaches an interval of temperatures comprised between 220°C and 450°C approximately. This depends on the operating conditions of the heat engine. Thus such regeneration is called low temperature passive regeneration of the first type.
• a high temperature passive or natural regeneration is also known, and occurs when the filter reaches temperatures exceeding 550°C. Such natural regeneration of the second type is very rare.
• PM-CAT filters may be provided as part of the original equipment or they can be bought aftermarket and installed on the vehicle, since such devices do not affect the management devices of the heat engine.
• DPF filters are closed filters, they completely filter the exhaust gases and they tend to clog due to the saturation of particulate matter, in spite of the presence of such passive regeneration process.
• high temperature active regeneration cycles with temperatures from 560°C and an average value of 650°C, are commanded and managed by a control unit, in order to promote a reaction of the second type, this time being active, namely generating CO/CO 2 from the reaction of the accumulated carbonaceous soot C with the oxygen 0 2 , thus freeing the DPF filter and allowing the engine apparatus/exhaust line (ATS) to restore its original performance.
• a control unit in order to promote a reaction of the second type, this time being active, namely generating CO/CO 2 from the reaction of the accumulated carbonaceous soot C with the oxygen 0 2 , thus freeing the DPF filter and allowing the engine apparatus/exhaust line (ATS) to restore its original performance.
• ATS engine apparatus/exhaust line
• the gas temperature at the inlet of the DOC is usually held about at 400-450°C. Then due to the presence of HC, exothermal reactions are carried out within the DOC, so as the temperature at the outlet of the DOC increases by reaching said regeneration temperatures 560° - 650°C necessary for the filter following (downstream) the DOC.
• DPF filters cannot be installed aftermarket on vehicles that are not equipped with them originally, since they cannot manage the active regeneration cycles.
• Type-approval cycles performed by type-approval authorities include the test of the functioning of the heat engine according to predefined engine speed/power /time curves.
• the engine apparatus/exhaust line passes the type approval tests.
• Type approval cycles and emission limits change according to the type of vehicle. The actual operating conditions of the vehicle may be very different from the type approval cycles conditions.
• the vehicles originally equipped with PM-CAT filters may be used in a way different from the type-approval curves, thus the filters can be completely saturated and the particulate matter produced by the heat engine will be almost totally released in the environment .
• Another problem that may occur is called “blow off", wherein at certain temperatures and with some very high levels of filter saturation, high flow rates of exhaust gases may carry away the soot on the walls of the alveoli, releasing it in the environment .
• diagnosis systems detecting the saturation level of the PM-CAT filters are adopted.
• An example of such systems is given in WO2012082268.
• a first aim of the present invention is to reduce the manufacturing and installation costs of exhaust gas treatment systems (ATS).
• Another aim of the present invention is to prolong the service life of PM-CAT filters.
• a further aim of the present invention is to improve the exhaust gas treatment systems based on PM-CAT filters, so that they can be more efficient, safe, and even suitable to very low-power work cycles.
• the service life of PM-CAT filters is prolonged and their functioning is more constant and reliable in time, to the point that the treatment systems based on such filters are suitable to be installed on all vehicle categories.
• PM-CAT filters - that do not have any superficial treatment with noble metals (platinum, palladium, etc.) - may used also in fields where only DPF filters have been used so far.
• It is also object of the present invention an internal combustion engine comprising the aforementioned exhaust gas treatment system and a vehicle comprising such engine.
• FIG 1 schematically shows a catalyst-filter system according to the present invention
• figure 2 schematically shows an ATS system according to the present invention, which integrates the catalyst-filter system shown in figure 1.
• the system that is object of the present invention provides the active regeneration of PM-CAT filters similarly to what happens for DPF filters.
• the active regeneration may be a process per se known, which includes, for example, the post- injection of additional fuel during some specific strokes of the engine, so that the fuel burns in the exhaust gas treatment system (in particular within the DOC) rather than in the cylinders, promoting an active reaction of the second type, namely the oxidation of the carbon residues by means of oxygen .
• the expression "to induce an active regeneration” will mean to increase the temperature of the ATS by enriching the fuel/air ratio and by fuel post- injection techniques or the like, namely independently of the work point and of the work conditions of the internal combustion engine.
• the enrichment of the fuel/air ratio is used to manage the DOC inlet temperature, while the post-in ections to manage the further temperature increasing within the DOC, exploited into the particulate filter.
• filter unable to retain all the particulate matter will refer to any open particulate filter different from DPF .
• the regeneration temperature of any filter depends also on the amount of particulate matter accumulated in the filter.
• PM-CAT filters of the same regeneration techniques as DPF filters for the same filter saturation percentage will cause an excessive increase of the temperatures reached during the regeneration process, which would damage the PM-CAT filters.
• the management of the regeneration of the PM-CAT filter is performed on the basis of a predictive estimation of the saturation level of the filter.
• a predictive estimation of the accumulation of particulate matter avoids to reach particulate levels that may bring to an uncontrollable second type regeneration, both passive and active.
• the predictive estimation is known in the field of DPF filters, but, if it was used as it is in the field of PM-CAT filters, it would be inadequate, since it would bring to an estimation of soot accumulation such that the regeneration should be five times more frequent than in the DPF filters.
• the estimator of the saturation level of the filter is based on :
• - a second model of the efficiency of the promotion of the first type reaction in order to estimate a second amount of particulate converted into CO/CO 2 , namely by a reaction based on the reduction of O 2 in NO, preferably within an interval of temperatures comprised between 220°C and 450°C;
• - a third model of the efficiency of the promotion of the second type reaction in order to estimate a second amount of particulate naturally converted into CO/CO 2 , namely by a natural reaction based on the reduction of O 2 during the functioning of the heat engine, which brings the ATS within an interval of temperatures comprised between 550°C and 650°C.
• the first amount of particulate matter gives an additional contribution, by settling in the alveoli of the PM-CAT filter, while the other two are subtracted from the first one.
• the first amount is higher than the absolute value of the sum of the other two, above all when the engine operates in low power conditions, namely when the exhaust line does not reach a temperature that is high enough to allow a natural reaction of the first type.
• the present invention teaches how to apply the active regeneration to the PM-CAT filter.
• PM-CAT filters According to laboratory tests on specific intervals of temperature, (220 - 450°C), PM-CAT filters have proven to be more efficient than DPF filters in the promotion of first type reactions having a coefficient comprised between 1.6 and 2.
• the predictive estimation in particular the second model, is modified in order to take into account the higher efficiency of the PM- CAT filters with respect to the DPF filters in promoting the reaction of the first type.
• said second amount with respect to a DPF filter, is multiplied by a coefficient comprised between 1.6 and 2.
• Such coefficient represents a ratio between the efficiency of the PM-CAT filter and of the DPF filter in promoting the natural regeneration of the first type .
• the reason of such anomalous behaviour is connected to the intrinsic characteristics of PM-CAT filters, which filtrate only 50% - 90% of the particulate produced by the heat engine.
• the first model of the grade of smoke which depends only on the characteristics of the heat engine, was weighted with a coefficient comprised between 0.5 and 0.9, namely equal to the filtration/capture/retention efficiency of the particulate matter filter.
• a first temperature sensor Tl is provided between the DOC and the PM-CAT. In this way the temperature is constantly monitored in order to avoid that it exceeds 650°C, which usually happens during the regeneration of the DPF filters. During the experimentation further problems have arisen.
• PM-CAT filters unlike DPF filters, allow the passage of unburnt hydrocarbons, since the PM-CAT filter does not have any superficial treatment with noble metals (platinum, palladium, etc.) that can remove/convert the HC .
• noble metals platinum, palladium, etc.
• the present invention such problem has been solved by increasing the temperature at the inlet of the DOC to a minimum value of 500°C and to an optimal value of 550°C.
• the second temperature sensor T2 arranged upstream of the DOC and the first temperature sensor Tl arranged between the DOC and the PM-CAT allow to monitor in detail the regeneration process.
• such optimal interval of temperatures is reached by enriching the mixture, namely by lowering the lambda which represents the ratio between air and fuel.
• the temperature control strategy just upstream the PM-CAT namely by means of Tl, allows to ensure a temperature of about 600 +/-50°C in the PM-CAT, which is lower than the regeneration temperature of the DPF .
• the control of temperature at the filter namely at the outlet of the DOC, can be controlled through the post injections suitable to carry out the exothermal reaction within the DOC needed for increasing of 50-100°C the temperature of the gas flow through the filter.
• the temperature difference between the inlet and the outlet of the DOC is at least 50°C lower than in the DOC of the know systems .
• the lambda varies in relation to the power/torque required to the engine, but the enriching that is necessary to promote the reaction, preferably of the second type, since it is more rapid, combined with the normal decrease of the lambda may result as intolerable, since the remarkable grade of smoke of the engine, above all when the power requests exceed 40% of the maximum power, induces the system to release particulate matter beyond the admissible limits. This happens because the PM-CAT filter is an open filter .
• maps of fuel supply/grade of smoke, different from the ones of the normal operating conditions of the vehicle have been used in order to give a lower limit to lambda corresponding to values between 1.5 and 1.1.
• the fuel supply map is unchanged until a remarkable torque/power is required, namely exceeding a preset threshold, for example 50% of the maximum power. Beyond such threshold, a device limiting the enrichment intervenes, namely a limiting device which avoids that the lambda goes below the aforementioned values.
• the enrichment curve is smoothed, according to any law, for example in the lambda interval between 1.5 and 1.1, wherein the lower limit, 1.1, cannot be passed.
• a filter-saturator may be used in order to avoid the enrichments to exceed 1.1 - intended as a lower limit - and possibly to level/smooth the progression of the enrichment in the interval between 1.5 and 1.1, wherein 1.1 is the lower limit.
• filter for the limiting means, is attributed to a logical function commonly used to program the engine control units through controllist ic schemes.
• An example of limiting means is given for example on US20040084015.
• intervals of intervention of the limiting means may be varied according to the characteristics of the engine, to the presence of the supercharging, etc..
• a PM-CAT filter can be used as an alternative to a DPF filter in the field of the DPF filter usage.
• the service life of the PM- CAT filter can be extended extraordinarily and the use of the vehicle can be also very different from the usage curves of the type-approval cycles. An optimal behaviour of the system can be guaranteed regardless of its usage.
• FIG. 1 shows a schematic view of a portion of the ATS system that is object of the present invention, comprising a catalyst C and an open-part iculate filter F with a first temperature sensor placed between the catalyst and the filter .
• a second temperature sensor T2 is placed upstream of the catalyst C and a lambda sensor is placed upstream the second temperature sensor T2.
• FIG. 2 shows an overall schematic view of the ATS system interacting with an internal combustion engine E.
• the estimator is integrated in the ECU which is connected to the aforementioned sensors Tl, T2, lambda and which controls the injection and the post-in ection of the fuel by means of the injectors J in the cylinder chambers of the internal combustion engine E.
• the present invention may advantageously be realized by means of a computer program, which comprises program code means performing one or more steps of said method, when said program is run on a computer.
• program code means performing one or more steps of said method
• the scope of the present patent is meant to cover also said computer program and the computer-readable means that comprise a recorded message, such computer-readable means comprising the program code means for performing one or more steps of such method, when such program is run on a computer.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Exhaust Gas After Treatment (AREA)
• Processes For Solid Components From Exhaust (AREA)

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• 2013
  • 2013-07-31 ES ES13756332T patent/ES2729005T3/es active Active
  • 2013-07-31 EP EP13756332.6A patent/EP2880291B1/de active Active
  • 2013-07-31 WO PCT/EP2013/066087 patent/WO2014020063A1/en active Application Filing
  • 2013-07-31 EP EP13755974.6A patent/EP2880289A1/de not_active Withdrawn
  • 2013-07-31 WO PCT/EP2013/066091 patent/WO2014020065A1/en active Application Filing
  • 2013-07-31 EP EP13755975.3A patent/EP2880290B1/de active Active
  • 2013-07-31 ES ES13755975T patent/ES2700145T3/es active Active
  • 2013-07-31 WO PCT/EP2013/066089 patent/WO2014020064A1/en active Application Filing

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