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
  • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
  • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
  • F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
  • F01N3/025—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust
  • F01N3/0253—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust adding fuel to exhaust gases
• • 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
  • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
  • F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
• • 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
  • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
  • F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
  • F01N13/0097—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series the purifying devices are arranged in a single housing
• • 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
  • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
  • F01N13/011—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more purifying devices arranged in parallel
• • 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
  • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
  • F01N3/0821—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents combined with particulate filters
• • 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
  • F01N3/2033—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using a fuel burner or introducing fuel into exhaust duct
• • 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
  • F01N3/204—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using an exhaust gas igniter, e.g. a spark or glow plug, without introducing fuel into exhaust duct
• • 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
  • F01N3/2053—By-passing catalytic reactors, e.g. to prevent 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
  • F01N2410/00—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device
  • F01N2410/02—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device in case of high temperature, e.g. overheating of catalytic reactor
• • 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
  • F01N2410/00—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device
  • F01N2410/04—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device during regeneration period, e.g. of particle 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
  • F01N2410/00—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device
  • F01N2410/06—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device at cold starting
• • 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
  • F01N2410/00—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device
  • F01N2410/12—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device in case of absorption, adsorption or desorption of exhaust gas constituents
• • 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
  • F02D2200/0802—Temperature of the exhaust gas treatment apparatus
• • 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
  • F02D41/1454—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 an oxygen content or concentration or the air-fuel ratio
• • 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 present invention relates to an exhaust gas purifying system of an internal combustion engine.
• An exhaust gas from an internal combustion engine contains harmful substances such as NOx (nitrogen oxide) .
• NOx nitrogen oxide
• a NOx catalyst for purifying the exhaust gas of NOx is provided in an exhaust system of the internal combustion engine in order to decrease emissions of these harmful substances.
• a temperature of the NOx catalyst is low, there might be a case that a NOx purifying efficiency decreases. Accordingly, the temperature of the NOx catalyst needs increasing up to a temperature at which the exhaust gas can be sufficiently purified of NOx.
• the exhaust gas from the internal combustion engine contains particulate matters (PM) ofwhichamain component is carbon.
• PM particulate matters
• Aknown technology for preventing the emissions of these particulate matters into the atmospheric air involves providing an exhaust system of the internal combustion engine with a particulate filter (which will hereinafter simply be termed a [filter]) for trapping (scavenging) the particulate matters .
• a particulate filter which will hereinafter simply be termed a [filter]
• scavenging the particulate matters
• a temperature of the filter is raised by increasing the temperature of the exhaust gas introduced into the filter, andthe trappedparticulate matters are removed by oxidation, thus scheming to regenerate the exhaust gas purifying performance of the filter (which will hereinafter be referred to as a [PM regenerating process] ) .
• the filter temperature needs increasing up to the temperature at which the particulate matters trapped by the filter can be sufficiently removed by oxidation.
• An exhaust passageway of the internal combustion engine is formed of a single exhaust pipe on an upstream side of the exhaust gas purifying device, and a portion configuring a passageway through which the exhaust gas passes and a portion provided with a catalyst heating up the exhaust gas by emitting heat upon being supplied with a reducing agent, are provided in parallel with each other in the exhaust pipe. Then, in the exhaust gas flowing through the exhaust pipe, allocation of a quantity of the exhaust gas passing through the catalyst heating up the exhaust gas and a quantity of the exhaust gas passing through the passageway, is set changeable.
• an exhaust gas purifying system of an internal combustion engine comprising: an exhaust gas purifying device provided in an exhaust passageway of the internal combustion engine, purifying an exhaust gas passing through the exhaust passageway andheatedup to a predetermined temperature or higher with the result that purifying capability thereof is improved; exhaust gas temperature increasing means provided on an upstream side of the exhaust gas purifying device in the exhaust passageway; and reducing agent adding means provided on the upstream side of the exhaust gas temperature increasing means in the exhaust passageway and adding a reducing agent to the exhaust gas passing through the exhaust passageway, an improvement is characterized in that the exhaust gas temperature increasing means includes: an exhaust gas temperature increasing catalyst provided in a single exhaust pipe configuring the exhaust passageway so that an exhaust gas flow-through area trough which the exhaust gas should pass is left, supplied with the reducing agent added from the reducing agent adding means and thereby emitting heat; and an exhaust gas flow rate control device controlling, in the exhaust gas passing though the exhaust pipe, allocation of a quantity of the exhaust gas passing the exhaust gas flow-through area and a quantity of
• the NOx catalyst in the case of purifying the exhaust gas of the NOx by the NOx catalyst provided in the exhaust system of the internal combustion engine, the NOx catalyst needs to have a temperature equal to or higher than an activation temperature at which the NOx can be occluded. Further, in the case of executing the PM regenerating process on the filter provided in the exhaust system, it is required that a temperature of the filter be kept equal to or higher than a temperature at which the particulate matters trapped by the filter can be removed by oxidation.
• the exhaust gas not passing through the exhaust gas temperature increasing catalyst is to flow directly into the NOx catalyst or the filter.
• a bypath via which the exhaust gas bypasses the exhaust gas temperature increasing catalyst is provided separately from the exhaust pipe.
• the exhaust passageway comes to have a complicated structure, and there was a possibility that mountability on a vehicle declines or it becomes difficult to reduce costs.
• the exhaust gas temperature increasing means is provided on the upstream side of the exhaust gas purifying device in the exhaust passageway.
• the exhaust gas temperature increasing catalyst is provided in the single exhaust pipe configuring the exhaust passageway so as to occupy part of the section of the exhaust pipe, and a remaining area of the section of the exhaust pipe is set as the exhaust gas flow-through area throughwhich the exhaust gas passes .
• the exhaust gas flow rate control device can control, in the exhaust gas flowing through the exhaust pipe, the allocation of the quantity of the exhaust gas passing through the exhaust gas flow-through area and the quantity of the exhaust gas passing through the exhaust gas temperature increasing catalyst.
• the exhaust gas temperature increasing catalyst and the exhaust gas flow-through area can be formed in parallel with each other in an interior of the single exhaust pipe configuring the exhaust passageway, and hence a contact area between the exhaust gas temperature increasing catalyst and the external portion of the exhaust passageway can be decreased to the greatest possible degree . Further, when the exhaust gas passes through the exhaust gas flow-through area, the heat of the exhaust gas can be efficiently transferred to the exhaust gas temperature increasing catalyst . As a result thereof, the heat retaining property of the exhaust gas temperature increasing catalyst can be improved.
• both of the exhaust gas temperature increasing catalyst and the exhaust gas flow-through area through which the exhaust gas passes can be provided in the single exhaust pipe, and the structure can be thus simplified, whereby the mountability of the exhaust gas purifying system on the vehicle can be improved, and the cost reduction can be also attained.
• the exhaust gas flow-through area may be disposed in a central portion in section perpendicular to an exhaust gas pass-through direction in the exhaust pipe, and the exhaust gas temperature increasing catalyst may be disposed outwardly of the exhaust gas flow-through area within the section.
• the temperature of the exhaust gas purifying device tends to be high at its central portion and becomes lower as it gets closer to a peripheral portion thereof. This is attributed to an escape of the heat into the outside air from the outer peripheral portion of the exhaust gas purifying device.
• the exhaust gas flow-through area throughwhich the exhaust gas passes is disposed at the central portion in the section perpendicular to an exhaust gas pass-through direction in the exhaust pipe, and the exhaust gas temperature increasing catalyst is disposed outside of the exhaust gas flow-through area within the section ,
• the exhaust gas temperature increasing catalyst can be distributed over the outer peripheral portion in the section perpendicular to the exhaust gas pass-through direction in the exhaust pipe.
• the exhaust gas flow rate control device may be set capable of selecting, by controlling the allocation, a state where substantially an entire quantity of the exhaust gas flowing through the exhaust pipe passes through the exhaust gas flow-through area, a state where substantially the entire quantity of the exhaust gas flowing through the exhaust pipe passes through the exhaust gas temperature increasing catalyst, and a state where substantially the entire quantity of the exhaust gas flowing through the exhaust pipe passes through both of the exhaust gas flow-through area and the exhaust gas temperature increasing catalyst.
• the exhaust gas flow rate control device selects the state where substantially the entire quantity of the exhaust gas flowing through the exhaust pipe passes through the exhaust gas temperature increasing catalyst, and the reducing agent adding means adds the reducing agent to the exhaust gas , whereby the exhaust gas temperature increasing catalyst is supplied with the entire quantity of the exhaust gas and can get the reducing reaction caused by the reducing agent.
• the exhaust gas flow rate control device selects the state where substantially the entire quantity of the exhaust gas flowing through the.exhaust pipe passes through the exhaust gas flow-through area, whereby the exhaust gas can be flowed directly into the exhaust gas purifying device without passing through the exhaust gas temperature increasing catalyst.
• the exhaust gas purifying device can be heated up by a thermal energy of the exhaust gas. Further, when the temperature of the exhaust gas purifying device is high and in a low-load operation, the exhaust gas temperature increasing catalyst can be restrained from becoming an excessively high temperature by flowing a comparatively low-temperature exhaust gas directly into the exhaust gas purifying device.
• the high-temperature exhaust gas can be restrained from further flowing into the exhaust gas temperature increasing catalyst. This makes it possible to restrain the exhaust gas temperature increasing catalyst from becoming the excessively high temperature.
• the temperature of the exhaust gas discharged from the internal combustion engine is low such as when in the low-load operation, the low-temperature exhaust gas can be restrained from flowing into the exhaust gas temperature increasing catalyst. This makes it feasible to restrain the decrease in temperature of the exhaust gas temperature increasing catalyst.
• the exhaust gas flow rate control device selects the state where the exhaust gas flowing through the exhaust pipe passes through both of the exhaust gas flow-through area and the exhaust gas temperature increasing catalyst, whereby the exhaust gas heated up as it passes through the exhaust gas temperature increasing catalyst and the exhaust gas not passing through the exhaust gas temperature increasing catalyst can be flowed in a properlymixed state thereof into the exhaust gas purifying device. This enables improvement of controllability of the temperature of the exhaust gas purifying device.
• the reducing agent adding means may add the reducing agent to the exhaust gas passing through the exhaust passageway, and the exhaust gas flow rate control device may control the allocation in order to make substantially the entire quantity of the exhaust gas flowing through the exhaust pipe pass through the exhaust gas temperature increasing catalyst, and the exhaust gas flow rate control device may, after the reducing agent added from the reducing agent adding means has reached the exhaust gas temperature increasing catalyst, control the allocation in order to decrease, in the exhaust gas flowing through the exhaust pipe, the quantity of the exhaust gas passing through the exhaust gas temperature increasing catalyst .
• the reducing agent adding means adds the reducing agent to the exhaust gas flowing through the exhaust passageway, and the exhaust gas flow rate control device controls the allocation in order for the exhaust gas temperature increasing catalyst to admit the passage of substantially the entire quantity of the exhaust gas flowing trough the exhaust pipe. Under this control, the reducing agent added from the reducing agent adding means can be efficiently led to the exhaust gas temperature increasing catalyst.
• the exhaust gas flow rate control device controls, in the exhaust gas flowing through the exhaust pipe, the allocation in order to decrease the quantity of the exhaust gas passing through the exhaust gas temperature increasing catalyst.
• Theallocationbeing thus controlled after the reducing agent has reached the exhaust gas temperature increasing catalyst, the flow rate of the exhaust gas passing though the exhaust gas temperature increasing catalyst decreases, and therefore the reducing agent can be restrained from passing intact through the exhaust gas temperature increasing catalyst. Then, the reducing agent can be stayed for a sufficiently long period of time in the exhaust gas temperature increasing catalyst. As a result, the sufficient reducing reaction can be caused in the exhaust gas temperature increasing catalyst, and the temperature of the exhaust gas discharged from the exhaust gas temperature increasing catalyst can be increased more surely.
• the exhaust gas flow rate control device may, during a decelerating operation of a vehicle mounted with the internal combustion engine, control the allocation in order to decrease, in the exhaust gas flowing through the exhaust pipe, the quantity of the exhaust gas passing through the exhaust gas temperature increasing catalyst.
• the temperature of the exhaust gas discharged from the internal combustion engine decreases.
• the temperature of the exhaust gas temperature increasing catalyst decreases, and there is a possibility that the temperature of the exhaust gas becomes hard to increase efficiently .
• the exhaust gas temperature increasing catalyst often has a smaller thermal capacity than the exhaust gas purifying device has, and hence there are many cases in which the temperature thereof especially tends to decrease due to the passage of the low-temperature exhaust gas .
• the exhaust gas flow rate control device may, in the exhaust gas flowing through the exhaust pipe, decrease the guantity of the exhaust gas passing through the exhaust gas temperature increasing catalyst.
• FIG. l isa view showing an internal combustion engine according to a first embodiment of the present invention and showing outlines of configurations of an exhaust system and a control system thereof;
• FIG.2 is a flowchart showing an exhaust gas purifying device temperature increasing routine in the first embodiment of the present invention
• FIG. 3 is a flowchart showing another example of the exhaust gas purifying device temperature increasing routine in the first embodiment of the present invention
• FIG. 4 is a view showing an exhaust gas temperature increasing device according to a second embodiment of the present invention and showing an outline of configuration of an exhaust gas purifying device;
• FIG. 5 is a view showing the exhaust gas temperature increasing device according to the second embodiment of the present invention and showing another mode of the outline of configuration of the exhaust gas purifying device;
• FIG. 6 is a view showing the exhaust gas temperature increasing device according to the second embodiment of the present invention and showing still another mode of the outline of configuration of the exhaust gas purifying device.
• FIG . l isa view showing an internal combustion engine according to a first embodiment and showing outlines of configurations of an exhaust system and a control system thereof .
• An internal combustion engine 1 shown in FIG. 1 is classified as a diesel engine. Note that an interior of the internal combustion engine 1 and an intake system thereof are omitted in FIG. 1.
• an exhaust gas purifying device 10 which purifies the exhaust gas from NOx and particulate matters (e.g., soot), is disposed downstream in the exhaust pipe 5.
• an exhaust gas temperature increasing device 11 which increases the temperature of the exhaust gas purifying device 10 by increasing a temperature of the exhaust gas flowing into the exhaust gas purifying device 10, is disposed upstream of the exhaust gas purifying device 10 in the exhaust pipe 5.
• This exhaust gas temperature increasing device 11 is partitioned by a partition pipe 11a having approximately the same diameter as a diameter of the exhaust pipe 5 off into an internal pipe portion lib and an external pipe portion lie.
• the internal pipe portion lib is provided with a flow rate control valve Hd that determines how a flow rate of the exhaust gas flowing through the internal pipe portion Hb and a flow rate of the exhaust gas flowing through the external pipe portion Hc are allocated by changing a flow rate of the exhaust gas passable through the internal pipe portion Hb.
• the external pipe portion Hc is provided with an oxidation catalyst He having oxidation capability so that the external pipe portion Hc is filled with the oxidation catalyst He.
• a fuel adding valve 12 for adding a fuel as a reducing agent to the exhaust gas flowing through the exhaust pipe 5 is disposed on the upstream side of the exhaust gas temperature increasing device 11 in the exhaust pipe 5.
• the exhaust gas temperature increasing device 11 corresponds to exhaust gas temperature increasingmeans .
• the oxidation catalyst He corresponds to an exhaust gas temperature increasing catalyst.
• the internal pipe portion lib corresponds to an exhaust gas flow-through area.
• the fuel adding valve 12 corresponds to reducing agent adding means.
• the flow rate control valve Hd configures an exhaust gas flow rate control device .
• the exhaust gas purifying device 10 in the first embodiment is a device constructed so that a wall-flow type filter composed of a porous base material supports an oxidation catalyst typified by platinum (Pt) and NOx occlusion agent typified by potassium (K) and cesium (Cs) .
• the exhaust gas purifying device 10 does not necessarily have to, however, be a device that support the NOx occlusion agent, wherein, for example, the NOx catalyst may be separately independently provided in the exhaust pipe 5.
• an electronic control unit (ECU) 35 for controlling the internal combustion engine 1 and the exhaust system is provided.
• This ECU 35 is a unit for performing, in addition to controlling an operating state etc of the internal combustion engine 1 in accordance with operating conditions of the internal combustion engine 1 and in response to a request of a driver, the control of an exhaust gas purifying system including the exhaust gas purifying device 10, the exhaust gas temperature increasing device 11 and the fuel adding valve 12.
• Unillustrated sensors related to the control of the operating state of the internal combustion engine 1 such as an airflow meter, a crank position sensor and an accelerator position sensor, are connected via electric wirings to the ECU 35, wherein output signals of these sensors are inputted to the ECU 35.
• an unillustrated fuel injection valve etc for combustion in the internal combustion engine 1 is connected via the electric wiring to the ECU 35, and, in addition, the flow rate control valve Hd, the fuel adding valve 12 etc in the first embodiment are connected via the electric wirings to the ECU 35, whereby these connected components are controlled.
• the ECU 35 is equipped with a CPU (Central Processing Unit (Central Processing Unit (Central Processing unit (Central Processing unit (Central Processing unit (Central Processing unit (CPU)).
• CPU Central Processing Unit
• ROM Read-Only Memory
• RAM Random Access Memory
• the ROM is preinstalled with programs for executing various categories of control of the internal combustion engine 1 and is stored with a map registered with data.
• the programs preinstalled in the ROM of the ECU 35 include, as one category of the program, a PM regenerating process routine (of which an explanation is omitted) for regenerating PM trapping (scavenging) capability of the exhaust gas purifying device 10, a NOx reduction process routine for reducing and thus purifying the NOx occluded in the NOx catalyst in the exhaust gas purifying device 10, similarly a SOx regenerating process routine (of which an explanation is omitted) for reducing and thus purifying SOx occluded in the NOx catalyst in the exhaust gas purifying device 10, and, in addition, an exhaust gas purifying device temperature increasing routine in the first embodiment, which will be described later on.
• the exhaust gas purifying device 10 when starting up the internal combustion engine 1 according to the first embodiment, if a temperature of the exhaust gas purifying device 10 is low, there might be a case in which the NOx catalyst in the exhaust gas purifying device 10 does not yet reach an activation temperature and is therefore incapable of sufficiently purifying the NOx in the exhaust gas that is discharged from the internal combustion engine 1. Then, the exhaust gas discharged from the internal combustion engine 1 is released without purifying the exhaust gas of the NOx, and such a possibility might arise that the emission is deteriorated.
• the first embodiment shall take such a contrivance that when starting up the internal combustion engine 1, if the temperature of the exhaust gas purifying device 10 is low, a quantity of the exhaust gas passing though the internal pipe portion lib is decreased or zeroed by driving the flow rate control valve Hd on a valve-closing side, and the fuel is added as a reducing agent from the fuel adding valve 12.
• the fuel added from the fuel adding valve 12 is efficiently supplied to the oxidation catalyst lie, and reducing reaction is efficiently caused in the oxidation catalyst He, thereby increasing the temperature of the exhaust gas discharged from the oxidation catalyst He.
• This operation enables the high-temperature exhaust gas to flow into the exhaust gas purifying device 10, whereby the exhaust gas purifying device 10 can be immediately warmed up.
• the exhaust gas temperature increasing device 11 is disposedwithin the exhaust pipe 5 without branching the exhaust pipe 5 configuring an exhaust passageway.
• the internal pipe portion Hb and the external pipe portion Hc are provided within the exhaust pipe 5, and the oxidation catalyst He is disposed so that the external pipe portion Hc is filled with the oxidation catalyst He.
• the exhaust gas temperature increasing device 11 takes a configuration that makes it harder for the heat of reaction that is generated in the oxidation catalyst lie to effuse outside than in the configuration of branching off into the exhaust passageway containing the oxidation catalyst and the bypath, and hence a heat retaining property of the oxidation catalyst lie can be improved.
• the oxidation catalyst lie is disposed in the external pipe portion lie within the exhaust pipe 5, and therefore the high-temperature exhaust gas can be supplied concentratedly to an outer peripheral portion of a front edge surface of the exhaust gas purifying device 10. As a result, a central portion of the front edge surface of the exhaust gas purifying device 10 can be restrained from having a excessively higher temperature than at the outer peripheral portion, whereby the exhaust gas purifying device 10 can be uniformly warmed up on the whole.
• FIG .2 shows the exhaust gas purifying device temperature increasing routine in the first embodiment, and this is a routine for increasing a temperature of the NOx catalyst up to the activation temperature if the NOx catalyst of the exhaust gas purifying device 10 does not yet reach the activation temperature.
• This routine is executed by the ECU 35 at an interval of predetermined time during the operation of the internal combustion engine 1.
• a catalyst temperature T defined as the temperature of the NOx catalyst of the exhaust gas purifying device 10 is acquired.
• This catalyst temperature T may be deduced in a way that detects a temperature of cooling water of the internal combustion engine 1 by use of an unillustrated cooling water temperature sensor, and the temperature of the exhaust gas discharged from the exhaust gas purifying device 10 may also be detected directly by an unillustrated exhaust gas temperature sensor.
• a relationship between elapsed time since the startup of the internal combustion engine 1 has begun and the catalyst temperature T is previously obtained, and the catalyst temperature T may also be deduced from the elapsed time since the startup of the internal combustion engine 1 has begun .
• the operation proceeds to S102.
• InS102 it is judgedwhether the catalyst temperature T is equal to or higher than the activation temperature of the NOx catalyst in the exhaust gas purifying device 10. Then, when judging that the catalyst temperature T is equal to or higher than the activation temperature of the NOx catalyst in the exhaust gas purifying device 10, the exhaust gas purifying device 10 is judged to be in a state capable of purifying the exhaust gas of the NOx that is discharged from the internal combustion engine 1, and hence the operation proceeds to S107.
• the flow rate control valve Hd is fully opened. Through this valve opening, the exhaust gas discharged from the internal combustion engine 1 flows directly into the exhaust gas purifying device 10 and is purified of the NOx therein.
• the judgment that the fuel added from the fuel adding valve 12 reaches the oxidation catalyst lie may be made by reading, into the ECU 35, an output of an unillustrated air-fuel ratio sensor provided upstream immediately of the oxidation catalyst lie, and may also be made by knowing that the temperature of the oxidation catalyst lie starts abruptly increasing.
• a relationship between the operating state of the internal combustion engine 1 and a period of time till the fuel added from the fuel adding valve 12 reaches the oxidation catalyst lie is mapped beforehand, and the above judgment may be made based on whether or not there is an elapse of the time read from the map in accordance with the operating state of the internal combustion engine 1 when executing the exhaust gas purifying device temperature increasing routine since the fuel has been added from the fuel adding valve 12. If it is judged in S105 that the fuel does not yet reach the oxidation catalyst lie, the operation returns to a status before the process in S105, wherein it is again judged in S105 whether the fuel added from the fuel adding valve 12 reaches the oxidation catalyst lie or not. Then, the process in S105 is repeatedly executed till judging that the fuel reaches the oxidation catalyst lie. Subsequently, when judging in S105 that the fuel reaches the oxidation catalyst lie, the operation proceeds to S106.
• the predetermined opening degree is an opening degree capable of sufficiently restraining the fuel reaching the oxidation catalyst lie from passing intact through the oxidation catalyst lie and amply supplying the exhaust gas having its temperature increased in the oxidation catalyst lie to the exhaust gas purifying device 10 in order to increase the temperature of the exhaust gas purifying device 10.
• This predetermined opening degree may be previously mapped in relation with the operating state of the internal combustion engine 1 and may be , when executing SlO6, derivedby reading from the map the opening degree corresponding to the operating state of the internal combustion engine 1 on this occasion.
• the catalyst temperature increasing routine in the first embodiment is that if the temperature of the NOx catalyst in the exhaust gas purifying device 10 is lower than the activation temperature, the flow rate control valve Hd is fully closed, and the fuel is added into the exhaust gas from the fuel adding valve 12, thereby making it possible to ensure transportability enough for having the added fuel reached the oxidation catalyst He.
• the flow rate control valve Hd is opened, and the exhaust gas from the internal combustion engine 1 flows to both of the external pipe portion lie and the internal pipe portion lib, whereby the fuel reaching the oxidation catalyst lie can be refrained from passing intact through the oxidation catalyst lie within the short period of time, and the exhaust gas the temperature of which has been increased by the reducing reaction in the oxidation catalyst lie can be suppliedmore surely to the exhaust gas purifying device 10.
• the flow rate control valve Hd may be opened to a much larger opening degree, and an inflow quantity of the exhaust gas discharged from the internal combustion engine 1 into the oxidation catalyst He may thus be decreased to a greater degree.
• the low-temperature exhaust gas in the decelerating state of the internal combustion engine 1 can be refrained from flowing into the oxidation catalyst He, and the oxidation catalyst He can be also restrained from being cooled down.
• FIG. 3 shows an example of the exhaust gas purifying device temperature increasing routine in that case.
• a different point between the control in the present routine and the control in FIG.2 is that in the present routine, after judging in S105 that the fuel reaches the oxidation catalyst lie, the operation proceeds to not S106 but S201. It is judged in S201 whether the internal combustion engine 1 is in the decelerating state or not. To be specific, -an output of an unillustrated accelerator position sensor is read into the ECU 35, and it may be judged whether an accelerator tread-on quantity obtained from this value is zero or not. A state where the accelerator is not trodden on may be defined as the decelerating state.
• the exhaust gas purifying device 10 can be warmed up more surely. It should be noted that in the first embodiment, when the internal combustion engine 1 is judged to be in the decelerating state in S201, if the flow rate control valve Hd is fully opened in S107, it follows that the low-temperature exhaust gas flows directly into the exhaust gas purifying device 10. In this case also, however, the exhaust gas purifying device 10 has a larger thermal capacity than the oxidation catalyst lie has, and hence such a problem, it is considered, is hard to occur that the exhaust gas purifying device
• the second embodiment will exemplify another configuration of the exhaust gas temperature increasing device 11 explained in FIG. 1.
• FIG. 4 is a view showing an outline of the configuration of the exhaust gas temperature increasing device 11 in the second embodiment .
• a first mode of the second embodiment is that as illustrated in FIG. 4(A), an exhaust gas purifying device 20 and an exhaust gas temperature increasing device 21 are substantially egualized in their diameters and are provided within a pipe having the same diameter. According to the first mode, the exhaust gas can be more smoothly flowed into the exhaust gas purifying device 20 without disturbing the flow of the exhaust gas discharged from the exhaust gas temperature increasing device 21.
• a stepped portion 21f in FIG. 4 (A) is not positioned between the exhaust gas temperature increasing device 21 and the exhaust gas purifying device 20. It is therefore possible to restrain a large amount of heat from escaping outwardly of the exhaust pipe 5 because the exhaust gas discharged from the oxidation catalyst 21e flows against the stepped portion 21f.
• FIG. 4 (B) illustrates another mode of the second embodiment.
• the oxidation catalyst 21e is provided not in the external pipe portion 21c but in an internal pipe portion 21b. With this arrangement, the oxidation catalyst 21e does not abut on the external portion of the exhaust pipe 5, whereby the heat retaining property of the oxidation catalyst 21e can be more enhanced.
• FIG. 5 shows a state where the flow rate control valve 21d is opened, while FIG. 5 (B) shows a state where the flow rate control valve 21d is fully closed.
• FIG. 6 illustrates still another mode of the second embodiment.
• an electro-thermic heater 21g is provided in the oxidation catalyst 21e. Then, when heating up the exhaust gas purifying device 20, tobeginwith, the electro-thermic heater 21g is electrified to emit the heat, thereby increasing the temperature of the oxidation catalyst 21e itself. When done so, it is feasible to increase the temperature of the oxidation catalyst 21e itself over the activation temperature more surely and to raise the temperature of the exhaust gas flowing into the exhaust gas purifying device 20 more certainly.
• a glow plug 21h is provided upstream immediately of the oxidation catalyst 21e. Then, when heating up the exhaust gas purifying device 20, at first, the glow plug 21h is electrified to emit the heat, the temperature of the oxidation catalyst 21e itself is increased, and the temperature of the exhaust gas passing through the external pipe portion 21c is raised. Then, the fuel is added from the fuel adding valve 12. With this operation, the temperature of the oxidation catalyst 21e itself can be increased over the activation temperature with more of the certainty, and the temperature of the exhaust gas discharged from the oxidation catalyst 21e can be further increased. Accordingly, the temperature of the exhaust gas flowing into the exhaust gas purifying device 20 can be raised more certainly.
• the embodiments discussed above have exemplified the case of warming up the exhaust gas purifying device 10 or 20 when starting up the internal combustion engine 1.
• the configurations and the control in the embodiments discussed above maybe applied to a case of increasing the temperature of the NOx catalyst or of the filter in a SOx poisoning recovery process and in the PM regenerating process of the filter in the exhaust gas purifying device 10 or 20.
• the embodiments discussed above have exemplified the example of adding the fuel as the reducing agent from the fuel adding valve 12, however, these embodiments may be applied to the exhaust gas purifying system that involves using urea water as the reducing agent. Moreover, these embodiments may also be applied to the exhaust gas purifying system of the internal combustion engine other than the diesel engine. In addition, these embodiments may also be applied to the exhaust gas purifying system adding the fuel as the reducing agent by executing the sub-injection such as VIGOM injection, POST injection, etc., from a fuel injection valve of the internal combustion engine .
• the sub-injection such as VIGOM injection, POST injection, etc.
• full-close state of the flow rate control valve Hd in the embodiments discussed above does not necessarily mean completely closed state of valve . It can include the state that the flow rate control valve Hd is closed to a sufficiently small opening degree with which substantially an entire quantity of the exhaust gas from the internal combustion engine 1 can flow into the oxidation catalyst He.
• the temperature of the exhaust gas purifying device in the exhaust system of the internal combustion engine can be increased more efficiently or more surely with the much simpler configuration.

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• 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)
• Processes For Solid Components From Exhaust (AREA)
• Filtering Of Dispersed Particles In Gases (AREA)
• Exhaust Gas Treatment By Means Of Catalyst (AREA)

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• 2005
  • 2005-03-28 JP JP2005091485A patent/JP2006274838A/ja active Pending
• 2006
  • 2006-03-28 CN CNA200680001358XA patent/CN101080557A/zh active Pending
  • 2006-03-28 EP EP06730956A patent/EP1864004A1/en not_active Withdrawn
  • 2006-03-28 US US11/795,338 patent/US20080120966A1/en not_active Abandoned
  • 2006-03-28 WO PCT/JP2006/307008 patent/WO2006104240A1/en active Application Filing

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