Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D21/00—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas
  • F02D21/06—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas peculiar to engines having other non-fuel gas added to combustion air
  • F02D21/08—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas peculiar to engines having other non-fuel gas added to combustion air the other gas being the exhaust gas of engine
• • 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 ; Methods of operation or control of catalytic converters
  • F01N3/2006—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
• • 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 ; Methods of operation or control of catalytic converters
  • F01N3/2006—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
  • F01N3/2046—Periodically cooling catalytic reactors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
  • F02M26/22—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with coolers in the recirculation passage
  • F02M26/23—Layout, e.g. schematics
  • F02M26/25—Layout, e.g. schematics with coolers having bypasses
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/02—EGR systems specially adapted for supercharged engines
  • F02M26/04—EGR systems specially adapted for supercharged engines with a single turbocharger
  • F02M26/05—High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
  • F02M26/22—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with coolers in the recirculation passage
  • F02M26/33—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with coolers in the recirculation passage controlling the temperature of the recirculated gases
• • 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 invention relates to a method and an apparatus for a combustion engine with a catalyst which is designed to clean engine exhaust gases.
• the invention also relates to a diesel engine for a heavy vehicle which incorporates such an apparatus.
• Catalysts are commonly used in today's vehicle engines with the object of reducing various kinds of harmful components in exhaust gases.
• a problem of today's catalysts for vehicle engines is that they function best within a limited temperature range which constitutes their working range and that they cannot work optimally at temperatures outside that working range. This means that if the catalyst is designed to work within a certain temperature range, its effectiveness will be reduced at temperatures outside that range, thereby leading to increased emissions of harmful substances from the engine.
• the catalyst will work with reduced effectiveness during those parts of the driving cycle in which the exhaust temperature is such that the working temperature of the catalyst is outside the working range. During those parts of the driving cycle, the discharge of various harmful substances will therefore be increased.
• Attempts to deal with this problem have inter alia involved devices for providing the catalyst with a separate heating device to ensure that the catalyst works as far as possible within a stated prescribed operating temperature range.
• that solution entails a relatively expensive device which is sensitive to operational disturbances resulting in increased cost and in sensitivity to operational disturbances.
• Another solution involves driving with heightened exhaust back-pressure, i.e. by setting an exhaust damper, resulting in increased application of power even when operating at low load, at the cost of causing the vehicle to consume more fuel.
• One object of the present invention is to indicate a method and a device whereby the problems of the state of the art are eliminated or at least reduced.
• a particular object of the invention is to provide an economic and operationally reliable solution whereby the catalyst is allowed to work within its working range.
• the invention is combined advantageously with cooled exhaust gas feedback, which is particularly relevant in high-power driving.
• a preferred arrangement for making this possible is to incorporate an exhaust cooler which is connected or bypassed respectively to supply cooled or uncooled gases to the engine's inlet. Such an arrangement allows easy and reliable regulation with a minimum of ductwork and valve devices to be adjusted.
• Fig. 1 depicts schematically a combustion engine with equipment for exhaust gas feedback
• Fig. 2 depicts a flowchart of a method for exhaust gas feedback.
• ref. 1 denotes a multi-cylinder turbocharged combustion engine of diesel type, with an exhaust manifold 2 and an inlet manifold 3.
• the exhaust gases from the exhaust manifold 2 are led via an exhaust line 4 to a catalyst 5 before being discharged to the environment.
• the engine may for example be intended to power a heavy vehicle.
• the exhaust gases Upstream from the catalyst 5, the exhaust gases pass through a turbo unit incorporating a turbine 6 which drives a compressor 7 situated in an air inlet line 8 to provide supercharging of the engine.
• a transfer line 9 for transferring exhaust gases to the inlet side of the engine is situated between the exhaust line 4 and the air inlet line 8.
• the transfer line 9 is provided with a bypass line 15 which incorporates an exhaust cooler 10 for cooling the gases transferred to the engine, h addition, the line 9 incorporates a section 9a which is situated beside the exhaust cooler 10 and through which exhaust gases can pass from the engine's exhaust side to the engine's inlet side without passing through the exhaust cooler 10.
• This section which incorporates a controllable valve 11, thus makes it possible to transfer uncooled exhaust gases to the engine's inlet side.
• the transfer line 9 also incorporates a second valve 12 which is controllable to regulate the whole exhaust gas quantity transferred between the exhaust side and the inlet side of the engine 1.
• a control unit 13 which in practice may take the form of an integrated part of a control unit for an engine which incorporates an apparatus according to the invention, is designed to regulate the valves 11 and 12 on the basis of measured, calculated or estimated exhaust temperature, and hence the working conditions for the catalyst 5.
• an exhaust temperature gauge 20 may with advantage be incorporated in the exhaust line 4 downstream from the turbine 6.
• the control unit 13 has sensors connected to it which deliver signals representative of exhaust temperature 20, accelerator pedal position 21 and engine speed 22. The possibility of other sensors being connected to the control unit 13 is not excluded.
• Fig.2 illustrates a sequence of a method for regulating the valves 11 and 12 which is performed under the control of the control unit 13:
• the exhaust temperature is calculated from a value of said momentary fuel quantity.
• other parameters may also be taken into account, e.g. outside temperature, vehicle speed etc.
• the exhaust temperature calculated at 16 is compared with a prescribed exhaust temperature range within which a catalyst forming part of the system exhibits optimum or at least good operation. If the exhaust temperature calculated at 16 is found to be below the prescribed range, a control system (13 in Fig. 1) is activated at 18 to supply uncooled exhaust gases to the engine's inlet side.
• the extent of the exhaust gas temperature range within which the catalyst works well depends on the type of catalyst, how it is dimensioned and how attuned it is to expected operating situations. In the case of diesel engines, particularly those intended for motor vehicles, the exhaust gas temperature during normal miscellaneous operation may range far beyond what a normal catalyst can reasonably be expected to handle with good cleaning results. A normal range typically covers about 200°C for a conventional catalyst for a combustion engine of a heavy vehicle. Exhaust temperatures below or above that range entail impaired effectiveness. Exhaust temperatures above the range may also damage the catalyst, so it is very important that the latter be designed to cope reliably with operating situations in which particularly high exhaust temperatures may be expected.
• Ref. 19 denotes the end of the sequence.
• Fig. 2 may be supplemented so that the guidance of exhaust gases to the engine's inlet side can ensure that cooled gases can be transferred in operating conditions which entail high engine load and problems of smoke in exhaust gases, or when necessary for other reasons.
• valves 11 and 12 are preferably such that the respective valve is either fully open or fully closed, since this type of operation is simpler than the control of proportional valves. According to the invention, however, the possibility of the valves 11 and/or 12 being variably controllable, whether in certain steps or steplessly between fully open and fully closed, is not excluded.
• catalysts of the kind here intended work optimally within a certain temperature range. This means that their effectiveness is reduced at catalyst temperatures outside that temperature range. Preventing the catalyst being exposed to too high exhaust temperatures is taken care of according to one aspect of the invention by sufficient cooled gases being transferred to the inlet side of the engine to bring the temperature down to the intended level. A function to this effect may also be added to the flowchart in Fig. 2.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Exhaust Gas After Treatment (AREA)
• Exhaust-Gas Circulating Devices (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)
• Combined Controls Of Internal Combustion Engines (AREA)

Applications Claiming Priority (3)

Publications (1)

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Family Applications (1)

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Citations (5)

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• 2001
  • 2001-11-30 SE SE0104037A patent/SE523514C2/sv not_active IP Right Cessation
• 2002
  • 2002-11-27 WO PCT/SE2002/002178 patent/WO2003046354A1/en active Application Filing
  • 2002-11-27 JP JP2003547767A patent/JP2005510652A/ja active Pending
  • 2002-11-27 EP EP02791146A patent/EP1463880A1/de not_active Withdrawn
  • 2002-11-27 AU AU2002365540A patent/AU2002365540A1/en not_active Abandoned

Patent Citations (5)

Non-Patent Citations (1)

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